Management of Diabetes Mellitus in Acromegaly and Cushing’s Disease with Focus on Pasireotide Therapy

Abstract: Patients suffering from acromegaly and Cushing’s Disease (CD) face the risk of several clinical complications. The onset of diabetes mellitus (DM) is among the most important: exposure to elevated growth hormone or cortisol levels is associated with insulin resistance (IR). DM contributes to increasing cardiovascular risk for these subjects, which is higher compared to healthy individuals. Hyperglycemia may also be caused by pasireotide, a second-generation somatostatin receptor ligand (SRLs), currently used for the treatment of these diseases. Accordingly, with 2014 medical expert recommendations, the management of hyperglycemia in patients with CD and treated with pasireotide is based on lifestyle changes, metformin, DPP-4 inhibitors (DPP-4i) and, subsequently, GLP-1 Receptor Agonists (GLP-1 RAs). There is no position for SGLT2-inhibitors (SGLT2-i). However, a very recent experts’ consensus regarding the management of pasireotide-induced hyperglycemia in patients with acromegaly suggests the use of GLP-1 RAs as first line treatment (in suitable patients) and the use of SGLT2-i as second line treatment in patients with high cardiovascular risk or renal disease. As a matter of fact, beyond the hypoglycemic effect of GLP1-RAs and SGLT2-i, there is increasing evidence regarding their role in the reduction of cardiovascular risk, commonly very high in acromegaly and CD and often tough to improve despite biochemical remission. So, an increasing use of GLP1-RAs and SGLT2-i to control hyperglycemia is desirable in these diseases. Obviously, all of that must be done with due attention in order to minimize the occurrence of adverse events. For this reason, large studies are needed to analyze the presence of potential limitations.

Keywords: acromegaly, Cushing’s disease, pasireotide, hyperglycemia, diabetes mellitus, cardiovascular risk

Introduction

Acromegaly and Cushing’s Disease (CD) are rare but weakening endocrine diseases.

Acromegaly is usually caused by a growth hormone (GH)-secreting pituitary adenoma, with subsequent excess of insulin-like growth factor (IGF-1).1 CD is characterized by hyperproduction of cortisol due to an adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma.2 Impaired glucose metabolism and the onset of DM are common clinical conditions resulting from these diseases. The worsening of glycemic control might also be caused by treatment with somatostatin receptor analogs, more specifically with pasireotide.

Pasireotide, a second-generation somatostatin receptor ligand (SRLs), is currently used for the treatment of acromegaly and CD.3,4

In the management of acromegaly, long-acting pasireotide is recommended at a starting dose of 40 mg monthly (potentially up-titrated to 60 mg) in patients with poorly controlled or uncontrolled disease after failure with first generation SRLs. Several Randomized Control Trials (RCTs) have shown better outcomes in achieving biochemical control compared to octreotide and lanreotide, both in parallel arms as well as in a cross-over evaluation.5,6 In CD, pasireotide is approved for the treatment of persistent hypercortisolism after a surgical procedure or when surgery is not feasible or refused, at a start dose of 0.6 mg twice daily (potentially up titrated to 0.9 mg twice daily).7,8

Hyperglycemia and Increased Cardiovascular Risk in Acromegaly and CD

Impaired glucose metabolism is one of the comorbidities associated with acromegaly and CD, uniquely linked to the pathophysiology of the diseases. As a matter of fact, in acromegaly, the prevalence of altered basal glucose ranges between 7 and 22%, of altered glucose tolerance between 6 and 45%, and of diabetes between 19 and 56%.9 Additionally, disorders of carbohydrate metabolism occur in 14–74% of the patients among the various forms of hypercortisolism while the prevalence of diabetes varies between 21 and 47%.10

The pathogenesis of insulin resistance (IR) in acromegaly is due to multiple factors: GH exerts its effects both directly by inducing gluconeogenesis, glycogenolysis and lipolysis and promoting IR in the liver and peripheral tissues, as well as indirectly through IGF-1.11 GH stimulates the hydrolysis of triglycerides and the production of free fatty acids from adipose tissue, and this increased synthesis of free fatty acids leads to a decrease in insulin-mediated glucose uptake by inhibiting glucose transporters GLUT-1 and GLUT-4.12,13 Moreover, GH suppresses key insulin signaling pathways involved in stimulating glucose transport in muscle and adipose tissue and inhibiting glucose production in the liver.14

The effects of IR secondary to the excess of GH are initially compensated by the increased secretion of insulin from the pancreatic beta cells, which, however, diminishes over time, favoring the onset of prediabetes and diabetes.15,16 Once the beta cell function is affected, the glucose metabolism disorders persist even after the acromegaly is cured.17 Although physiologically IGF-1 improves glucose homeostasis, the chronic excess of GH in acromegaly that causes IR greatly exceeds the possible beneficial effects of IGF-1 on insulin sensitivity.18

Similar to the excess of GH, hypercortisolism affects carbohydrate metabolism mainly in liver, skeletal muscles, and adipose tissue.19 In the liver, excess glucocorticoids stimulate gluconeogenesis by activating numerous genes involved in the hepatic gluconeogenesis, stimulating lipolysis and proteolysis with increasing substrates for gluconeogenesis, potentiating the action of glucagon and inhibiting glycogenogenesis.20

In the muscle, hypercortisolism induces IR by interfering with different components of the insulin-signaling cascade, as well as by stimulating proteolysis and loss of muscle mass. All this reduces the capacity of the muscle to synthesize glycogen and uptake most of the postprandial glucose from circulation.21

Additionally, hypercortisolism causes an increase in visceral obesity and a relative reduction in peripheral adipose tissue, and this “shift” is closely associated with metabolic syndrome and worsens IR. Moreover, the excess of cortisol influences the synthesis and release of hormones from adipose tissue, mainly adipokines, further contributing to the development of IR.21

Glucocorticoids inhibit the synthesis and secretion of insulin. Also in CD, there is an initial transient phase characterized by the increase in insulin secretion as an adaptive mechanism to IR, but later the chronic exposure to higher levels of cortisol induces pancreatic beta cell apoptosis, loss of beta cell function and the subsequent development of diabetes.20,22

The involvement of the bone system in affecting glucose homeostasis has also been found: in fact, long-term exposure to glucocorticoids causes a reduction in circulating osteocalcin that can increase IR.23

Furthermore, two studies in humans24,25 suggested that secretion of incretins (glucagon-like peptide-1, GLP-1 and glucose dependent insulinotropic peptide, GIP) was unaffected by dexamethasone administration, but their insulinotropic effects of on beta-cells were reduced.

The worsening of glycemic control and the onset of DM are also important limitations in the management of some patients treated with pasireotide.26,27 This topic will be further explored in a subsequent paragraph.

As is well known, hyperglycemia contributes to increasing cardiovascular risk, which is already very high in patients with acromegaly or CD.28,29

Cardiovascular disease is the leading cause of death in 23–50% of patients with acromegaly in different studies.9 Hypertension affects about 33% of the patients, ranging from 11 to 54.7%,30 and it is strongly related with typical cardiac implications of acromegaly as valvulopathy, arrhythmias and cardiomyopathy.

In the large Liege Acromegaly Survey database of 3173 acromegalic patients from 10 European countries,31 left ventricular hypertrophy was present in 15.5% at time of diagnosis. The most common manifestations of cardiopathy are biventricular hypertrophy, diastolic-systolic dysfunction, and valvular regurgitation.32 Certainly, the severity of cardiac disease is correlated with age, duration of acromegaly, GH and IGF-1 levels (both vascular growth factors which stimulate collagen deposition) and long-standing hypertension.33 In the worst cases, hypertrophic cardiopathy can evolve into Left Ventricular Systolic Dysfunction (LVSD), the last stage of cardiac disease, with recurring hospitalizations and very high mortality rates.34 Acromegaly is also associated with sleep apnea (ranging from 45 to 80% of the cases).35

Similarly, in CD cardiovascular disease is the leading cause of death: a retrospective study involving 502 patients (83% in remission) with a median follow-up of 13 years36 demonstrated a standardized mortality ratio (SMR) of 3.3 (95% CI 2.6–4.3) for CV disease, in particular 3.6 (95% CI 2.5–5.1) for ischemic cardiac disease and 3.0 (95% CI 1.4–5.7) for stroke. SMR related cardiovascular disease remained higher also after biochemical remission (2.5, 95% CI 1.8–3.4).36 Cardiovascular remodeling caused by hypercortisolism is frequently irreversible: at 5 years post-remission, coronary artery plaques persisted in 27% of subjects vs 3% of control.37 As a result, the risk for ischemic events remains above that of the general population.38

Hypertension is highly prevalent in patients with hypercortisolism: the majority (80–85%) of patients have hypertension at diagnosis and 9% may have required hospital admission because of the hypertension crisis before the diagnosis of hypercortisolism.39 Also, after remission, hypertension results are highly prevalent, as shown in two different studies (50% and 40%, respectively).40,41 Up to 70% of the patients with active CD present abnormal left ventricular mass parameters, whereas systolic and diastolic function were usually normal. Rarely, patients present dilatative cardiopathy and severe HF.42 Moreover, greater incidence of hypokalemia exposes patients to fatal arrhythmias.

Finally, both obesity and dyslipidemia, frequently occurring in these diseases, do not normalize despite biochemical remission.

Mechanisms of Pasireotide-Induced Hyperglycemia

Pasireotide is a multi-receptor targeted SRL, with action on different somatostatin receptors (SSTR). Pasireotide binds with high affinity to SSTR-1, 3 and 5 and lower to SSTR-2 than first generation SSA. More specifically, the affinity for SSTR-5, several times greater than those of octreotide and lanreotide, explains the efficacy of pasireotide: this binding causes the suppression of ACTH and GH, accompanied by tumor volume reduction.43,44

However, this mechanism causes the alteration of glucose metabolism because the binding is not specific to pituitary cells. Stimulation of pancreatic SSTR-5, expressed more in Langerhans islet beta cells than alfa cells (87% vs 44%), suppresses insulin secretion much more than glucagon secretion.45

Pasireotide appears to inhibit the secretion of incretin hormones GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) in health volunteers after oral glucose tolerance test (OGTT),46 even if a recent study showed no differences in incretin levels and their response to mixed meal tolerance test (MMTT) in CD patients,47 suggesting a main role of direct inhibition of beta-cells activity. However, a reduced intra-islet paracrine effect of GLP-1 cannot be excluded whereas an increased IL-6 mediated GLP-1 secretion in CD may disguise pasireotide inhibitory effect.47,48 Furthermore, pasireotide has no effect on hepatic and peripheral insulin sensitivity.46

Pasireotide-induced hyperglycemia is less pronounced following multiple dosing, and it appears even reversible upon discontinuation of the drug,49 as shown in a pharmacokinetic analysis of single-dose administration, in which mean glucose levels increased to 200 mg/dL (11.1 mmol/L) and returned to euglycemia approximately 23 hours later.50

Not all patients treated with pasireotide develop impaired glucose tolerance or DM: the prevalence of these conditions in CD is respectively 21–64% and 20–47%,51 whereas in acromegaly it is 6–45% and 16–65%.9 This suggests that glycemic control prior to the treatment and a preceding DM, could be predictive of the extent of hyperglycemia.

In the PAOLA study6 a fasting blood glucose (FBG) > 100 mg/dL (5.5 mmol/L) at baseline correlated with higher FBG and higher HbA1c during treatment with pasireotide, while patients with acromegaly < 40 years of age were less likely to experience hyperglycemia than older patients.

Moreover, in acromegalic patients, the up-titration to a dose of 60 mg was associated with a 21–36% increased risk of hyperglycemia.52,53 Other factors that could increase the risk of hyperglycemia were a Body Mass Index > 30 kg/m², hypertension and dyslipidemia at baseline.54

Superimposable results were obtained in another Phase III study,55 always performed in subjects with acromegaly: it was reported that up to 45% of patients with baseline FBG between 100 (5.5 mmol/L) and 126 mg/dL (7.0 mmol/L) had FBG levels ≥126 mg/dL (7.0 mmol/L) after 26 months of pasireotide.55

Also, in CD, preexisting DM or impaired glucose tolerance increased the risk of hyperglycemia-related adverse events (AEs) with pasireotide, although severe AEs were not reported.7

A meta-analysis showed a lower frequency of hyperglycemia-related AEs in acromegalic patients treated with pasireotide monthly (57.3–67.0%) in comparison to those who received it twice daily for CD (68.4–73.0%).27 Also, the rate of discontinuation due to hyperglycemia was higher in CD trials (6.0% and 5.3%) than that in acromegaly trials (3.4% and 4.0%).5–7,56 The reasons for these findings are unknown.

On the other hand, it has been acknowledged that other drugs, commonly used for the treatment of acromegaly or CD, may affect glucose metabolism leading to clinical benefits, even during pasireotide therapy. In fact, in acromegalic subjects, cabergoline can improve glucose tolerance,57 whereas pegvisomant reduces fasting glucose levels and improves insulin sensitivity.58,59 Similar results have been highlighted for ketoconazole,60 metyrapone61 and osilodostrat62 in studies involving patients with CD.

Antidiabetic Drugs with Proven Cardiovascular Benefits

The evidence from Cardio Vascular Outcome Trials with GLP-1 RAs and SGLT2-i have revolutionized the management of Type 2 Diabetes Mellitus (T2DM). As reaffirmed in the recent American Diabetes Association-European Association for the Study of Diabetes (ADA-EASD) Consensus, the treatment approach must be holistic and person-centered, with four main areas of interest: glycemic control, weight loss, CV risk reduction and renal protection.63

In a network meta-analysis of 453 trials assessing glucose-lowering medications from nine drug classes, the greatest reductions in HbA1c were seen with GLP-1 RAs.64 Another meta-analysis comparing the effects of glucose-lowering drugs on body weight and blood pressure indicated the greatest efficacy for reducing body weight with GLP-1 RAs, whereas the greatest reduction in blood pressure is seen with the SGLT2-i.65

Among GLP-1 RAs, liraglutide (at a dose of 1.8 mg daily),66 dulaglutide (at a dose 1.5 mg weekly)67 and injectable semaglutide (at a dose of 0.5 and 1 mg weekly)68 reduced the incidence of three point-MACE (Major Adverse Cardiovascular Events) and the progression of CKD (Chronic Kidney Disease) through the reduction of albuminuria.

With regard to SGLT2-i, empagliflozin and canagliflozin reduced the incidence of three point-MACE.69,70 Empagliflozin, dapagliflozin and canagliflozin demonstrated improvement of CKD in trials with specific renal outcomes, and the first two also demonstrated this benefit in patients without T2DM.71–73 Another significant clinical benefit is the reduction of hospitalization for heart failure (HF), demonstrated also in patients without T2DM for empagliflozin and dapagliflozin, both with reduced ejection fraction (HFrEF)74,75 and preserved ejection fraction (HFpEF).76,77

The Current Management of Pasireotide-Induced Hyperglycemia

Several studies, performed with different designs, evaluated the impact of pasireotide on glucose metabolism. The principal results are summarized in Table 1.5–8,78–85

Table 1 Main Studies Regarding the Use of Pasireotide in Acromegaly and in Cushing’s Disease

It’s undeniable that impairment of glucose metabolism occurred: generally, in all studies the number of subjects with diabetes and prediabetes increased, HbA1c levels were higher and anti-hyperglycemic treatments were required. Metformin, DPP-4i and insulin were commonly used to treat hyperglycemia, whereas GLP-1 RAs and SGLT2-i were given only in a small number of cases.

Nevertheless, a recent randomized multicenter study involving 81 patients with acromegaly or CD receiving pasireotide86 and uncontrolled hyperglycemia with metformin or other oral antidiabetic medications (acarbose or sulfonylureas), evaluated the effects of two different regimens of treatment (incretin-based therapy vs insulin). All 38 patients randomized to an incretin-based therapy (acromegaly, n = 26; CD, n =12) received sitagliptin; 28 of them switched to liraglutide. Twelve patients (31.6% [CD, n = 6; acromegaly, n = 6]) randomized to incretin-based therapy received insulin as rescue therapy. The results have shown a trend for better control of HbA1c with incretin-based therapy. Furthermore, in the same study, 109 patients who received pasireotide did not develop hyperglycemia requiring antidiabetic treatment.86 These findings suggest that impaired glucose metabolism or onset of DM during pasireotide therapy are manageable in most patients, without the need for treatment discontinuation.

Accordingly, given the above-mentioned evidence, glycemia should be monitored in all patients treated with pasireotide in order to intercept an initial alteration of glucose metabolism which could be either prediabetes or DM, according to the indications of ADA.87 In patients treated with pasireotide, FBG and HbA1c levels tend to increase during the first 1–3 months of treatment and stabilize thereafter.88

Regarding CD, in 2014, a medical expert recommendation on pasireotide-induced hyperglycemia was published.89 In this, an HbA1c target value less than 7.0–7.5% (53–58 mmol/L) is established, avoiding as much as possible the risk of hypoglycemia. Patients in euglycemia prior to therapy must be monitored: they should self-check FBG and postprandial glucose (PPG) levels during the day, precisely twice in the first week and once weekly later. Instead, patients with prediabetes and DM must be monitored closely (after 1, 2 and 4 weeks), and they should self-check blood glucose values up to six times per day during the first week, and at least four times per day thereafter.26,89

Medical treatment should always include dietary modification and exercise. Metformin is the first line-therapy, unless contraindicated or not tolerated. If glycemic control is not reached or maintained with monotherapy, combination therapy with drugs targeting the incretinic axis is recommended:89 a Phase I study90 in 19 healthy volunteers randomized to pasireotide 600 μg sc bid alone or co-administered with antidiabetic drugs (metformin 500 mg bid, nateglinide 60 mg tid, vildagliptin 50 mg bid and liraglutide 0.6 daily) demonstrated greater effects of vildagliptin and liraglutide in minimizing hyperglycemia.

Therefore, therapy with a DDP-4i is suggested in a first step combination. Only in the case of failure to reach the HbA1c target, the replace of DDP-4i with a GLP-1 RAs is recommended. If pasireotide-induced hyperglycemia remains uncontrolled with combinations containing metformin and DPP-4i or GLP-1 RAs, experts’ recommendations suggest the beginning of basal insulin therapy. If the individual HbA1c targets are not achieved or the postprandial glucose levels remains elevated, prandial insulin can be added.89

Instead, in acromegaly, a very interesting experts’ consensus statement regarding the management of pasireotide-induced hyperglycemia has been recently published.91 It suggests monitoring blood glucose prior to initiation of pasireotide treatment, through the determination of HbA1c or FBG or the execution of OGTT. Patients are divided into three risk categories related to glycemic status: normal glucose tolerance (NGT) patients at low risk, NGT patients at high risk and prediabetic or diabetic patients. In low-risk patients with no worsening of glycemic control, self-measurement of blood glucose (FBG and PPG) once every week is considered sufficient. In high-risk patients who do not have elevated blood glucose levels, weekly self-monitoring (FBG and PPG) is recommended in the first three months. In patients with pre-existing hyperglycemia, daily self-monitoring in recommended with at least one FBG and one PPG, ideally as multiple-point profiles.91 Further, when possible and economically feasible, high-risk patients should temporarily be equipped with continuous glucose monitors (CGMs) to detect elevated blood glucose levels early and determine deviations from the time in range precisely. During treatment with pasireotide, HbA1c measurements should be routinely performed every three months and at least with each IGF-1measurement.91

For the treatment of hyperglycemia, this recent experts’ consensus statement represents an important leap forward from a conceptual point of view. As a matter of fact, glycemic targets are not strictly fixed but an individualized approach for each patient is suggested. Moreover, CV risk is introduced as a factor influencing the choice of antidiabetic drugs.

Obviously, lifestyle intervention (physical activity, healthy sleep, high-quality nutrition) is always suggested. Metformin is indicated as a first-line medication but, considering the high CV risk of acromegalic subjects, GLP-1 RAs with proven CV benefits could also be considered as a first-line treatment. DPP-4i are considered a viable alternative to GLP-1 RAs in case of gastrointestinal side-effects.91

However, studies demonstrated that 10–30% of acromegalic patients show a paradoxical increase in GH (PI-GH) during 75-g OGTT.3 This is probably due to the action of GIP, which is higher in acromegalic patients, particularly in those with hyperglycemia, and that is likely able to increase the secretion of GH.92,93 As is well known, DPP-4i reduce the incretin-degrading enzyme DPP-4 and thus increase the concentration of active incretins, including GIP. Accordingly, a recent study showed that sitagliptin, administered one hour before 75-g OGTT, increase GH in acromegalic patients, especially in those with PI-GH.94 For this reason, acromegalic patients should be carefully monitored for a potential worsening of the underlying disease during treatment with a DPP- 4i.

The use of SGLT2-i is recommended only as second-line treatment for patients with high CV risk and/or renal disease, despite their high prevalence in acromegaly.91 This is justified by the increased risk of diabetic ketoacidosis (DKA), a severe condition related to treatment with SGLT2-i, in acromegalic subjects.95–97 However, patients safely treated with pasireotide and SGLT2-i are reported.98

The addition of insulin may be considered, but it should ideally be used as an adjunct to metformin and at least one other therapeutic agent.

Obviously, in case of poor glycemic control despite treatment with several anti-hyperglycemic drugs, the dose reduction or even the discontinuation of pasireotide should be considered.

A Potential Change of Perspective and Open Issues

Considering the complex cardiovascular profile of patients with acromegaly and CD, a much greater use of GLP-1 RAs and SGLT2-i might be necessary if DM occurs. There are at least three important aspects that support this consideration: glycemic control, cardiovascular protection, and weight loss.

Accordingly, both in acromegaly and CD, the use of GLP-1 RAs contributes to the achievement of these three main goals, providing an important possibility to enhance the quality of life and to decrease the mortality of patients, with evident advantages compared to DDP-4i and insulin.86,91,99 In this regard, co-agonists of GLP-1 and GIP, such as tirzepatide, with their extraordinary impact in terms of HbA1c reduction and weight loss, represent a theoretically intriguing therapeutic option for the future, despite the current lack of data in acromegaly and CD.

SGLT2-i are not included in the expert recommendations for the patients with CD.89 Currently, there is not enough evidence to support their use, even if their impact on cardiorenal risk might be valuable.

The same reasoning could apply to the acromegalic subjects. In particular, the very favorable benefit of SGLT2-i on HF risk could be extremely crucial.

A proposal for an approach to contrasting hyperglycemia, also taking into account the higher cardio-renal risk, in acromegaly and CD is depicted in Figure 1.

Figure 1 Proposal for a new approach to treat hyperglycemia in patients with acromegaly or Cushing’s Disease, with or without pasireotide treatment. The restoration of euglycemia should be achieved with concomitant reduction in terms of weight and cardiovascular risk, improving quality of life and decreasing mortality.

Notes: The choice of anti-hyperglycemic drugs should be driven by high CV risk and not by the concomitant treatment for acromegaly and CD. In patients with dual therapy at baseline (Metformin + SGLT2-i or GLP-1 RAs) and glycemic control not achieved, follow the same indications reported in the figure. Consider DPP-4i in case of intolerance at SGLT2-i and GLP-1 Ras; Consider BASAL INSULIN as first therapy in case of severe glycometabolic state (HbA1c > 10%, FBG > 300 mg/dL, clinical signs of catabolism). In patients with high risk of ketoacidosis and positive anamnesis for recurrent genitourinary infections, SGLT2-i should be avoided.

Potential limits are higher costs and the risk of AEs. It is well known that the most common AEs of GLP-1 RAs are gastrointestinal (nausea, vomiting, and diarrhea) and tend to occur during initiation and dose escalation, diminishing over time.100 Same AEs are noted with pasireotide, even if described as non-severe.

Another AE common to both treatments (pasireotide and GLP-1 RAs) are cholelithiasis and gallbladder disease. Different meta-analysis of RCTs confirmed that GLP1-RAs are associated with an increased risk of cholelithiasis, in the absence of any relevant increase in the risk of pancreatitis and pancreatic cancer.101,102 It is notable that in the study which compared incretin-based and insulin therapy, patients in the latter group had a higher incidence of gallbladder or biliary-related AEs (23.3% vs 13.2%).86

Instead, as reported in the recent consensus about the management of hyperglycemia in acromegaly, a potential limit for the use of SGLT2-i is the risk of DKA, a condition characterized by hyperglycemia, metabolic acidosis and ketosis (pH ≤ 7.3, bicarbonate ≤ 15 mmol/L, anion gap > 12 mmol/L), fortunately rare in acromegaly, considering it concerns only 1% of all cases and it often occurs only in the initial disease manifestation.103 During treatment with SGLT2-i, DKA occurs in the absence of hyperglycemia, and so it also known as euglycemic diabetic ketoacidosis (EuDKA).104 The suggested mechanism behind the EuDKA is the reduction of insulin requirement in patient treated with SGLT2-i due to massive glycosuria, with concomitant increased gluconeogenesis (driven by an increase of glucagon), release of free fatty acid and subsequent propensity to ketone production.105

It is noteworthy that GH and cortisol themselves increase lipolysis, the lipid oxidation rate and so ketone bodies. Moreover, the shift in the insulin/glucagon ratio as observed in pasireotide treatment is thought to be especially prone to this metabolic complication, warranting greater caution.103

It’s essential to consider the higher risk of DKA or EuDKA during treatment with SGLT2-i, but it’s equally necessary to specify that their incidence appears significantly lower compared to that of a fatal cardiovascular event, both in acromegaly and CD. As a matter of fact, a multicenter retrospective study, during 2015–2020, in 9940 persons with T2DM treated with SGLT2-i has shown that the overall prevalence of DKA is around 0.43% (with 0.25% for EuDKA).106 Furthermore, even some real-life evaluations conducted in subjects with Type 1 Diabetes, a clinical condition with a well-known high risk of DKA and in which the use of SGLT2-i is actually contraindicated, have shown similar data: Stougard et al107 have observed an incidence of DKA equal to 0% in patients treated with SGLT2-i whereas Anson et al108 have observed a lower risk of DKA and associated hospitalization in subjects treated with SGLT-2i compared to those treated with GLP-1 RAs (obviously, as an adjunct to insulin therapy).

Additionally, in acromegalic subjects treated with pegvisomant, in monotherapy or in combination with pasireotide, the incidence of the EuDKA should be reduced. In fact, a reciprocal positive interaction could be achieved because SGLT2-i attenuate the hyperglycemic effect by decreased insulin secretion, meanwhile pasireotide in combination with pegvisomant mitigates the hyperglucagonemia induced by SGLT2-i. Also, pegvisomant decreases lipid oxidation via extrahepatic suppression of Growth Hormone Receptor in different tissues.109

Hence, it seems reasonable to encourage the use of SGLT2-i even in acromegalic patients treated with pasireotide, especially in those with well-controlled disease, modest hyperglycemia and undergoing combined treatment with pegvisomant. It should be helpful to advise them to discontinue therapy with SGLT2-i in case of intercurrent illnesses that may cause a reduction in carbohydrates intake and dehydration (eg, infections and gastroenteritis), and to not skip doses in the case of contextual insulin therapy. SGLT2-i should be avoided in patients with poorly controlled disease.

The same considerations could also be applied to patients with poorly controlled CD.

Another potential limit for the use of SGLT2-i, especially in CD patients for the overall increased risk of infection in this disease, is the higher prevalence of genitourinary infections, reported in both clinical trials and real world evidence. These infectious events are usually mild, and their prevalence is related to sex and a prior positive history of genital infections. In fact, the risk appears higher in females, and among them, in those with previous infections.110 Moreover, it is interesting to underline that in the study of McGovern et al110 the use of corticosteroids, a clinical condition similar to CD, higher values of HbA1c were not associated with significant additional infection risk in subjects treated with SGLT2-i.

Therefore, it is good clinical practice to suggest meticulous intimate hygiene to patients treated with SGLT-2i, avoiding the use of this class of drugs in those with positive anamnesis for genitourinary infections, especially for females.

It is also worth noting that neither GLP-1 RAs nor SGLT2-i cause hypoglycemia, another condition that significantly increases cardiovascular risk and mortality, as demonstrated in the ACCORD trial.111

Finally, a recent case report112 showed the positive effect of a combined therapy of GLP-1 RAs and SGLT2-i on pasireotide-induced hyperglycemia in a patient with CD. After the failure of metformin and DPP-4i, multiple daily insulin injections and, after two days, dulaglutide 0.75 mg were initiated. After improvement of glycemic control, 10 mg of empagliflozin was started and insulin discontinued. After 3 months, hypercortisolemia and glucose impairment were well-regulated, and the patient’s health improved overall.112

Despite several limits (not optimal use of insulin, short follow-up, lack of data regarding other parameters), this is an example of a treatment that is not glycemic-centered but focused to prevent and improve hypercortisolemia-related complications.

Needless to say, further investigations are needed to analyze the above-mentioned considerations and to overcome the limited findings available.

Ethics Statement

This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution and considerations, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Funding

The authors did not receive support from any organization for the submitted work.

Disclosure

The authors declare that they have no competing interests in this work.

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Diagnostic dilemma in Cushing’s syndrome: discrepancy between patient-reported and physician-assessed manifestations

Purpose

Early diagnosis and immediate treatment of Cushing’s syndrome (CS) are critical for a better prognosis but remain a challenge. However, few comprehensive reports have focused on this issue or investigated whether patient-reported manifestations are consistent with physician-assessed symptoms of CS. This study aimed to clarify the differences in patient-reported and physician-assessed manifestations of signs and symptoms of CS that prevent early diagnosis.

Methods

This single-center retrospective study included 52 patients with CS (16 with Cushing’s disease and 36 with adrenal CS). Upon clinical diagnosis, medical records were used to independently review the patient-reported and physician-assessed manifestations of typical (such as purple striae and proximal myopathy) and nonspecific features (such as hirsutism and hypertension). The correlations and differences between the patient-reported and physician-assessed manifestations were then analyzed.

Results

We observed a positive correlation between the total number of manifestations of nonspecific features reported by patients and those assessed by physicians, but not for typical features. Moreover, manifestations reported by the patients were less frequent than those assessed by physicians for typical features, leading to discrepancies between the two groups. In contrast, there were no differences in most nonspecific features between the patient-reported and physician-assessed manifestations. Notably, the concordance between patient-reported and physician-assessed manifestations of typical features was not associated with urinary free cortisol levels.

Conclusion

Regardless of disease severity, patients often do not complain of the typical features of CS that are crucial for formulating a diagnosis.

Introduction

Endogenous Cushing’s syndrome (CS) is caused by chronic and excessive glucocorticoid exposure. This occurs primarily due to adrenocorticotropic hormone (ACTH)-producing pituitary tumors (Cushing’s disease; CD) or cortisol-producing adrenal tumors (adrenal Cushing’s syndrome; ACS) [1]—and has a high mortality rate owing to cardiovascular disease, severe infection, and suicide, even when diagnosed and treated appropriately [12]. Moreover, the prognosis is poor if the disease is not adequately treated or remains undiagnosed [2]. Therefore, early diagnosis and immediate intervention are important, as remission of CS due to surgical and pharmacological treatment can reduce the risk of mortality [34].
CS is a rare disease with a prevalence of 57 per million individuals and an annual incidence of 3.2 per million, and its epidemiology is consistent across various regions worldwide [56]. Most symptoms and signs of CS are common in general metabolic disorders, including obesity, hypertension, osteoporosis, and diabetes mellitus [7]. However, CS should be suspected if these symptoms appear as unusual features for their age [18]. Consequently, the identification of CS is challenging and labor-intensive [1910]. In fact, recent research revealed that a definitive diagnosis of CD (the most common form of CS), took an average of 3.8 ± 4.8 years from the onset of symptoms, and patients typically consulted 4.6 ± 3.8 medical professionals before this disease was identified [11]. Typical features of CS include symptoms of moon face, central obesity, or buffalo hump [12], which are similar to other symptoms such as primary obesity and therefore can lead to misdiagnosis. Furthermore, although purple striae or thin skin with an increased propensity for bruising are other typical features of CS [12], these attributes are not commonly acknowledged by the general population [19].
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Attempts have been made to diagnose CS early, including the development of scoring systems to estimate the pre-test probability of CS and facial image analysis software to diagnose the specific facial features of CS [1315]; however, these have not yet been used widespread or fully and the early diagnosis of CS remains dependent on the experience-based medical skills of the clinical staffs [16].
Additionally, although it is difficult for patients to recognize complex and nonspecific symptoms [1718], the significance of patients recognizing their illness has recently been reported for various diseases such as heart failure and malignant carcinoma [1921]. It is widely acknowledged that patients’ self-recognition can result in early detection of the disease, reduce its severity and recurrence, and enhance their quality of life [19]. In patients with endocrine diseases, there is increasing focus on issues surrounding self-recognition [2224]. For example, a previous study focusing on acromegaly reported a discrepancy between patient-reported and physician-reported manifestations and indicated that resolving this discrepancy could shorten the time to diagnosis [25].
Identifying CS may be challenging for primary care physicians who are yet to specialize. Therefore, endocrinologists with extensive experience in CS have often noticed that patients and these physicians struggle to identify the symptoms of CS; however, few comprehensive reports have focused on this issue or investigated whether patient-reported manifestations are consistent with physician-assessed symptoms of CS.
Therefore, this study aimed to investigate the unreported manifestations of CS among individuals referred to non-specialist healthcare providers, including primary care physicians, and to recognize potential challenges with the current diagnosis of CS with the goal of facilitating early detection.
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Materials and methods

Patients, study design, and data collection

This single-center retrospective study was conducted to identify the discrepancies between patient-reported and physician-assessed symptoms and investigate the factors causing these differences.
From September 2004 to December 2022, 199 patients were referred to our department at a tertiary medical institution upon suspicion, evaluation, or follow-up for hypercortisolism. Of these patients, 92 were newly diagnosed with CS (36 with CD, 51 with ACS, and 5 with ectopic ACTH syndrome) based on the diagnostic guidelines [3812], with a diagnosis confirmed by pathological evaluation after surgical resection [26]. However, 35 patients were excluded due to a lack of detailed clinical data on the manifestations at diagnosis. Similarly, we excluded individuals diagnosed with ectopic ACTH syndrome because of the lack of comprehensive information on symptoms reported by the patients and primary care physicians due to the rapid progression and severity of this disease. Therefore, 52 patients (16 with CD and 36 with ACS) were enrolled in this study.
Upon clinical diagnosis, the manifestations included in the comprehensive standardized interview at the time of diagnosis and those assessed by the physician through collaborative assessment with multiple board-certified endocrinologists as routine practice were independently reviewed from the medical records. We categorized these manifestations reviewed from the medical records into the following two categories based on the diagnostic guidelines including those of the Japan Endocrine Society: typical features, including moon face, central obesity or buffalo hump, purple striae of ≥1 cm, thin skin and easy bruising, and proximal myopathy; and nonspecific features (shown as atypical in Japan Endocrine Society’s guideline), including hypertension, menstrual abnormalities, acne, hirsutism, peripheral edema, glucose metabolism impairment, osteoporosis, pigmentation (which is not expected in patients with ACS), and mental abnormalities [1812]. Central obesity or buffalo hump can also be observed in pseudo CS. However, in this study, features were classified as the same typical feature according to clinical guidelines [1227]. We also reviewed the biochemical findings, comorbidities, duration from the initial recognition of CS-related symptoms to diagnosis, and number of medical institutions visited before diagnosis.
The present retrospective study was performed in accordance with the Declaration of Helsinki and approved by the Ethics Committee of Kobe University Hospital (Approval No. 1351). The patients had the option of an opt-out process, and all procedures were part of routine medical care.

Definition of patient-reported and physician-assessed manifestations

In the context of routine clinical care, physicians asked the patients about the presence or absence of manifestations and comorbidities (e.g., hypertension, menstrual abnormalities, glucose metabolism impairment, osteoporosis, and mental abnormalities), which were documented in the medical records. These reports in the medical records were defined as patient-reported manifestations in this study. In contrast, the manifestations and comorbidities of CS were assessed within several weeks after the patient was referred to our department for suspected CS. Additional diagnostic information on comorbidities is provided in the subsequent section. Physician-assessed manifestations were subsequently defined based on these findings.

Comorbidities of Cushing’s syndrome

All comorbidities were diagnosed according to the appropriate guidelines [2830]. For example, hypertension was diagnosed if patients were taking oral antihypertensive medication or had more than grade 1 hypertension (≥140/90 mmHg) in a treatment-naïve state [28]. Moreover, glucose metabolism impairment—including diabetes mellitus, impaired glucose tolerance, and impaired fasting glucose—was diagnosed based on the results of blood glucose levels during fasting and after a 75-g oral glucose tolerance test, as well as hemoglobin A1c (HbA1c) levels [29]. Patients taking medications for diabetes mellitus at the time of CS diagnosis were also categorized as having diabetes.
Other comorbidities included mental abnormalities, menstrual abnormalities, and the presence of osteoporosis. Mental abnormalities were defined as the use of anxiolytic medications, sleeping pills, or antidepressants prescribed by experienced psychologists, and menstrual abnormalities were defined as women with irregular menstrual cycles. Furthermore, the presence of osteoporosis was defined as bone mineral density (BMD) of <–2.5 standard deviations (SD) of the T-score of the lumbar vertebrae (L2–L4), femoral neck, or distal radius measured using dual-energy x-ray absorptiometry (DXA; Horizon A DXA System), and/or an experience of a fragility fracture [30]. As per the specifications of the measurement system employed, L1 was not included in the assessment. The Z-score was also employed as a diagnostic reference among young adults. Patients also diagnosed with osteoporosis who were receiving medications for this disease.

Hormone assay

In this study, blood samples were collected after an overnight fast. Subsequently, serum cortisol levels were measured using a chemiluminescent enzyme immunoassay [CLEIA] (TOSOH, Tokyo, Japan, RRID:AB_3099658) or enzyme immunoassay [EIA] (TOSOH, Tokyo, Japan, RRID:AB_3076600). Similarly, plasma ACTH levels were measured using a CLEIA (TOSOH, Tokyo, Japan, RRID:AB_3099657, or Siemens, Tokyo, Japan, RRID:AB_2909441) and EIA (TOSOH, Tokyo, Japan, RRID:AB_2783633). In both methods, the measurements showed good correlation and no conversion was required [3132].
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Urinary free cortisol (UFC) levels were also measured using radioimmunoassays (RIA; TFB, Tokyo, Japan, RRID:AB_2894408) or chemiluminescent immunoassays (CLIA; Siemens, Tokyo, Japan, RRID:AB_2893154). Using the following formula, the UFC levels measured by RIA were then corrected to the value measured by CLIA: Y = 0.832X − 4.23 (Y = UFC levels using CLIA, X = UFC levels using RIA) [33].

Statistical analysis

All statistical analyses were performed using SPSS ver. 28.0 software (IBM Corp., Armonk, NY, USA). All continuous variables were analyzed using the Shapiro–Wilk normality test to confirm a normal distribution, whereas Fisher’s exact test was used to analyze categorical data. Between the two groups, differences in normally or non-normally distributed data were compared using the unpaired Student’s t-test or the Mann–Whitney U test, respectively.
Cohen’s kappa coefficient was used to describe the concordance between the patient-reported and physician-assessed manifestations. As previously reported [192034], the concordance based on the value of Cohen’s kappa coefficient was rated as follows: 0.00–0.20 for “Slight,” 0.21–0.40 for “Fair,” 0.41–0.60 for “Moderate,” 0.61–0.80 for “Substantial,” and 0.81–1.00 for “Almost Perfect.” For correlation analysis between two variables of non-normally distributed data, we used Spearman’s rank correlation coefficient. Multivariate logistic regression analyses were then performed to investigate variables associated with the discrepancies between patient-reported and physician-assessed manifestations.
The results are presented as mean ± SD for normally distributed data and median [interquartile range] for non-normally distributed data, and differences were considered statistically significant when the P value was <0.05.
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Results

Clinical characteristics of the patients

We included 52 patients diagnosed with CS in this study. Their clinical characteristics are presented in Table 1. Notably, this group consisted of 5 males and 47 females, with a mean age of 49.4 ± 15.8 years, median body mass index (BMI) of 23.0 [21.3–28.0] kg/m2, and median UFC level of 272.1 [126.0–435.0] µg/day. Of the CS patients, 16 had CD and 36 had ACS, which is consistent with epidemiological data on CS observed in Asians (including Japanese individuals); however, this differed from epidemiological data from Western countries [3536]. Regarding comorbidities, 43 patients were diagnosed with hypertension—of which 34 were prescribed antihypertensive medications—with a mean systolic blood pressure (BP) of 136.4 ± 21.5 mmHg and diastolic BP of 83.5 ± 15.0 mmHg. In addition, 44 patients were diagnosed with glucose metabolism impairment—of which, 20 were prescribed oral hypoglycemic agents and/or insulin—with a median fasting serum glucose level of 99.5 [87.3–116.5] mg/dL and median HbA1c level of 6.3% [5.7–7.4]. Moreover, 29 patients were diagnosed with osteoporosis, of which 4 were prescribed antiosteoporosis medication, with BMD T-score SDs of -1.54 ± 1.39, -1.76 ± 1.12, and -0.50 [-1.53–0.50] for the lumber spine, femoral neck, and distal radius, respectively. Notably, the UFC levels were higher in patients with CD than in those with ACS (412.6 [243.2–1,100.3] vs. 215.3 [114.0–387.8] µg/day); however, there were no significant differences attributed to sex, age, BMI, or the proportion of patients with respect to comorbidities, including hypertension and glucose metabolism impairment, between patients with CD and ACS.

Table 1

Clinical characteristics of the patients
Total
CD
ACS
CD vs. ACS P value
Number of men/women
5/47
1/15
4/32
1.00
Age (years)
49.4 ± 15.8
54.3 ± 19.2
47.2 ± 13.8
0.14
BMI (kg/m2)
23.0 [21.3–28.0]
24.7 [22.2–30.0]
22.8 [20.8–26.4]
0.17
Midnight F (µg/dL)
20.1 [16.0–23.5]
20.2 [13.9–24.7]
20.1 [16.9–23.0]
0.97
F after LDDST (μg/dL)
21.2 ± 6.9
24.2 ± 10.1
19.7 ± 4.2
0.11
UFC (μg/day)
272.1 [126.0–435.0]
412.6 [243.2–1,100.3]
215.3 [114.0–387.8]
0.02
Basal ACTH (pg/mL)
2.0 [0.0–53.9]
83.2 [57.4–169.9]
0.0 [0.0–2.1]
<0.01
Systolic BP (mmHg)
136.4 ± 21.5
140.5 ± 20.7
134.6 ± 21.8
0.36
Diastolic BP (mmHg)
83.5 ± 15.0
83.1 ± 14.3
83.6 ± 15.5
0.90
Use of antihypertensive drugs, n (%)
34 (65)
13 (81)
21 (58)
0.13
FSG (mg/dL)
99.5 [87.3–116.5]
110.0 [102.0–142.8]
92.5 [83.3–114.3]
0.01
HbA1c (%)
6.3 [5.7–7.4]
6.8 [5.9–8.6]
6.0 [5.7–7.1]
0.08
Use of OHA and/or insulin, n (%)
20 (38)
9 (56)
11 (31)
0.12
LS BMD T-score (SD)
−1.54 ± 1.39
−1.00 ± 1.38
−1.79 ± 1.35
0.07
LS BMD Z-score (SD)
−0.78 ± 1.37
0.13 ± 1.11
−1.20 ± 1.28
<0.01
FN BMD T-score (SD)
−1.76 ± 1.12
−1.73 ± 1.54
−1.78 ± 0.88
0.92
FN BMD Z-score (SD)
−0.79 ± 1.01
−0.39 ± 1.10
−0.99 ± 0.92
0.10
Radius BMD T-score (SD)
−0.50 [−1.53–0.50]
−0.30 [−2.50–0.40]
−0.60 [−1.30–0.60]
0.79
Radius BMD Z-score (SD)
0.60 [−0.60–1.50]
1.50[−0.60–1.80]
0.50[−0.50–1.00]
0.33
Use of antiosteoporosis drugs, n (%)
4 (8)
1 (6)
3 (8)
1.00
Time to diagnosis (months)
44.0 [13.3–125.3]
43.0 [15.0–128.3]
47.5 [12.5–125.3]
0.87
Number of medical institutions before diagnosis
3.0 [2.0–5.0]
3.0 [2.0–5.0]
3.0 [3.0–5.8]
0.23
The results are presented as mean ± SD for normally distributed data and median [interquartile range] for non-normally distributed data
CD Cushing’s disease, ACS adrenal Cushing’s syndrome, BMI body mass index, F cortisol, LDDST low-dose dexamethasone suppression test, UFC urinary free cortisol, ACTH adrenocorticotropic hormone, BP blood pressure, FSG fasting serum glucose, HbA1c hemoglobin A1c, OHA oral hypoglycemic agents, BMD bone mineral density, LS lumber spine, FN femoral neck
The median duration from the patients’ initial recognition of CS-related manifestations to diagnosis was 44.0 [13.3–125.3] months, and it took more than 3 years to diagnose CS in 30 patients (58%). Furthermore, the median number of medical facilities visited by patients before diagnosis was 3.0 [2.0–5.0]; however, there were no significant differences in the duration or number of medical institutions between patients with CD and those with ACS.

Frequency and concordance between patient-reported and physician-assessed CS-related manifestations

Each manifestation reported by a patient or assessed by a physician is shown vertically for individual cases in Fig. 1. Compared with nonspecific features, typical features appeared to not be reported by the patients but were only assessed by the physicians. In addition, compared to nonspecific features, there were fewer cases in which the manifestations reported by the patients were consistent with those assessed by physicians for typical features.

https://static-content.springer.com/image/art%3A10.1007%2Fs12020-024-03935-9/MediaObjects/12020_2024_3935_Fig1_HTML.png

Fig. 1

Consistency between patient-reported and physician-assessed manifestations for each individual case. The consistencies or discrepancies between patient-reported and physician-assessed manifestations are shown. Vertical lines represent manifestations in individual patients. CD Cushing’s disease, ACS adrenal Cushing’s syndrome
Consistent with the impact of these visually distinctive presentations shown in Fig. 1, no correlation was observed in the number of typical features between patient-reported and physician-assessed manifestations (r = –0.20, P = 0.16) (Fig. 2A), whereas a positive correlation was found for nonspecific features (r = 0.62, P < 0.01) (Fig. 2B). Moreover, the total number of patient-reported manifestations of typical features was lower than that of physician-assessed manifestations (1.0 [0.0–2.0] vs. 3.5 [3.0–4.0], P < 0.01), and four of the five typical features were reported less frequently by patients than by physicians, except for proximal myopathy (Table 2A). According to Cohen’s kappa coefficient, the concordance between patient-reported and physician-assessed manifestations was marked as “Fair” to “Slight,” indicating a discrepancy for all typical features. Similarly, the total number of patient-reported manifestations of nonspecific features was also lower than that in physicians (2.5 [2.0–3.0] vs. 4.0 [3.0–5.0], P < 0.01). However, except for glucose metabolism impairment or osteoporosis, there were no differences in the frequencies of nonspecific features between patient-reported and physician-assessed manifestations, and the concordance of the nonspecific features between the patient-reported and physician-assessed manifestations was “Almost perfect” for menstrual abnormality and “Substantial” for mental abnormality and hypertension, whereas that for glucose metabolism impairment and osteoporosis was “Fair.” This suggests that the discrepancy between patient-reported and physician-assessed manifestations was more significant for typical than for nonspecific features. However, no differences in these discrepancies were observed between patients with CD and those with ACS (Table 2B, C).

https://static-content.springer.com/image/art%3A10.1007%2Fs12020-024-03935-9/MediaObjects/12020_2024_3935_Fig2_HTML.png

Fig. 2

Correlation between the total number of patient-reported and physician-assessed manifestations. Correlations between the total number of patient-reported and physician-assessed manifestations are shown for typical (A) and nonspecific features (B). CD is plotted by ×, and ACS is plotted by ○. The Spearman’s rank correlation coefficients and P value are presented. CI confidence interval, CD Cushing’s disease, ACS adrenal Cushing’s syndrome
Table 2

Frequencies of patient-reported and physician-assessed manifestations and their concordance. A. All patients (n = 52). B. Patients with CD (n = 16). C. Patients with ACS (n = 36)
Patient-reported
Physician-assessed
P value of Fisher’s exact test
Concordance with Cohen’s kappa coefficient
A
Typical features
Moon face, n (%)
20 (39)
48 (92)
<0.01
Slight
Central obesity or buffalo hump, n (%)
13 (25)
44 (85)
<0.01
Slight
Purple striae, n (%)
3 (6)
15 (29)
<0.01
Fair
Thin skin and easy bruising, n (%)
15 (29)
43 (83)
<0.01
Slight
Proximal myopathy, n (%)
21 (40)
27 (52)
0.33
Slight
Nonspecific features
Hypertension, n (%)
39 (75)
43 (83)
0.47
Substantial
Menstrual abnormalities, n (%)
11 (21)
11 (21)
1.00
Almost perfect
Acne, n (%)
7 (14)
13 (25)
0.21
Moderate
Hirsutism, n (%)
3 (6)
10 (19)
0.07
Moderate
Peripheral edema, n (%)
24 (46)
28 (54)
0.56
Fair
Glucose metabolism impairment, n (%)
24 (46)
44 (85)
<0.01
Fair
Osteoporosis, n (%)
7 (14)
29 (56)
<0.01
Slight
Pigmentation, n (%)
0 (0)
5 (10)
0.06
Mental abnormalities, n (%)
17 (33)
17 (33)
1.00
Substantial
B
Typical features
Moon face, n (%)
6 (38)
14 (88)
0.01
Slight
Central obesity or buffalo hump, n (%)
6 (38)
15 (94)
<0.01
Slight
Purple striae, n (%)
2 (13)
4 (25)
0.56
Moderate
Thin skin and easy bruising, n (%)
4 (25)
13 (81)
0.06
Slight
Proximal myopathy, n (%)
8 (50)
8 (50)
1.00
Slight
Nonspecific features
Hypertension, n (%)
16 (100)
15 (94)
0.78
Slight
Menstrual abnormalities, n (%)
5 (31)
5 (31)
1.00
Almost perfect
Acne, n (%)
1 (6)
3 (19)
0.56
Moderate
Hirsutism, n (%)
2 (13)
4 (25)
0.56
Moderate
Peripheral edema, n (%)
8 (50)
10 (63)
0.56
Slight
Glucose metabolism impairment, n (%)
10 (63)
15 (94)
0.14
Slight
Osteoporosis, n (%)
4 (25)
9 (56)
0.15
Slight
Pigmentation, n (%)
0 (0)
5 (31)
0.14
Mental abnormalities, n (%)
5 (31)
6 (38)
0.78
Moderate
C
Typical features
Moon face, n (%)
14 (39)
34 (94)
<0.01
Slight
Central obesity or buffalo hump, n (%)
7 (19)
29 (81)
<0.01
Slight
Purple striae, n (%)
1 (3)
11 (31)
<0.01
Slight
Thin skin and easy bruising, n (%)
11 (31)
30 (83)
<0.01
Slight
Proximal myopathy, n (%)
13 (36)
19 (53)
0.24
Slight
Nonspecific features
Hypertension, n (%)
23 (64)
28 (78)
0.30
Substantial
Menstrual abnormalities, n (%)
6 (17)
6 (17)
1.00
Almost perfect
Acne, n (%)
6 (17)
10 (28)
0.40
Moderate
Hirsutism, n (%)
1 (3)
6 (17)
0.11
Fair
Peripheral edema, n (%)
16 (44)
18 (50)
0.81
Fair
Glucose metabolism impairment, n (%)
14 (39)
29 (81)
<0.01
Fair
Osteoporosis, n (%)
3 (8)
20 (56)
<0.01
Slight
Pigmentation, n (%)
0 (0)
0 (0)
Mental abnormalities, n (%)
12 (33)
11 (31)
1.00
Almost perfect
The frequencies of patient-reported and physician-assessed manifestations were compared using Fisher’s exact test. The concordance between patient-reported and physician-assessed manifestations was evaluated with Cohen’s kappa coefficient, and its coefficients were defined as follows: 0.00–0.20 for “Slight,” 0.21–0.40 for “Fair,” 0.41–0.60 for “Moderate,” 0.61–0.80 for “Substantial,” and 0.81–1.00 for “Almost perfect”
CD Cushing’s disease, ACS adrenal Cushing’s syndrome
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We performed logistic regression analyses using UFC to investigate whether excess cortisol levels influenced the discrepancy between patient-reported and physician-assessed manifestations. Notably, we observed no association between UFC levels and discrepancies between patient-reported and physician-assessed manifestations in the univariate or multivariate logistic regression analyses adjusted for sex and age (Table 3A). In addition, no association was observed after adjusting for other variables such as BMI and disease duration. Similarly, we found that the serum cortisol levels after the low-dose dexamethasone suppression test (LDDST) were not associated with discrepancies between patient-reported and physician-assessed manifestations (Table 3B). Thus, these disparities were shown to be insignificant when directly related to the severity of CS.

Table 3

Logistic regression analyses of the discrepancies between the patient-reported and physician-assessed manifestations. A. Variables associated with UFC levels. B. Variables associated with serum cortisol levels after the LDDST
Univariate
Multivariate 1 (sex- and age-adjusted)
Multivariate 2 (BMI-adjusted)
Multivariate 3 (disease duration-adjusted)
A
Moon face
1.000 (0.999–1.001)
1.000 (0.999–1.001)
1.000 (0.998–1.002)
1.000 (0.999–1.001)
Proximal myopathy
1.000 (0.999–1.001)
1.000 (0.999–1.001)
1.000 (0.998–1.001)
1.000 (0.998–1.001)
Thin skin and easy bruising
1.000 (0.998–1.001)
1.000 (0.999–1.001)
1.000 (0.999–1.001)
1.000 (0.998–1.001)
Central obesity or buffalo hump
1.001 (1.000–1.003)
1.001 (1.000–1.003)
1.001 (1.000–1.003)
1.001 (1.000–1.003)
Purple striae
1.000 (0.999–1.002)
1.000 (0.998–1.002)
1.001 (0.999–1.003)
1.000 (0.999–1.002)
B
Moon face
0.998 (0.919–1.084)
0.999 (0.919–1.086)
1.000 (0.920–1.088)
0.997 (0.918–1.082)
Proximal myopathy
1.007 (0.925–1.097)
1.007 (0.924–1.097)
1.007 (0.925–1.097)
1.006 (0.924–1.096)
Thin skin and easy bruising
1.022 (0.939–1.112)
1.018 (0.934–1.109)
1.023 (0.940–1.113)
1.019 (0.937–1.109)
Central obesity or buffalo hump
0.979 (0.890–1.078)
0.978 (0.865–1.105)
0.981 (0.875–1.099)
0.978 (0.887–1.078)
Purple striae
0.998 (0.919–1.084)
0.999 (0.919–1.086)
1.000 (0.920–1.088)
0.997 (0.918–1.082)
The results are presented as odds ratios (95% confidence intervals)
UFC urinary free cortisol, BMI Body Mass Index, LDDST low-dose dexamethasone suppression test

Discussion

In the present study, we highlight the challenges associated with the diagnosis of CS—a condition resulting from excessive glucocorticoid exposure—and elucidate the divergence between patient-reported and physician-assessed manifestations. Thus, this study may aid in the early detection of CS by identifying symptoms that patients are unable to recognize based on the disparities between patient-reported and physician-assessed manifestations of CS.
In this study, the number of patient-reported manifestations of both typical and nonspecific features was lower than that of physician-assessed manifestations, suggesting that CS symptoms may have been overlooked by relying solely on patient reports. Additionally, analysis of the concordance between patient-reported and physician-assessed manifestations revealed a tendency for these manifestations to be inconsistent for both typical and nonspecific features, with a tendency to be more significant for typical features. Furthermore, the UFC and serum cortisol levels after the LDDST, which represent the severity of CS, were not associated with the concordance of manifestations between patients and physicians, suggesting that even in cases of severe CS, patients may not recognize their symptoms. These findings imply that typical features, which are essential for diagnosing CS, may be difficult for patients to recognize and poorly identified or conveyed to patients by non-specialist physicians, who are typically the first to interact with individuals with CS. The importance of educating healthcare providers such as primary care physicians, family physicians and gynecologists for early diagnosis of CS should be highlighted.
According to a previous report on the diagnostic history of 176 patients with CD, 83% of the patients visited their family physician for manifestations such as weight gain and hypertension, while 46% visited a gynecologist for menstrual abnormalities before the diagnosis of CD [11]. Thus, the typical features of CS were not recognized. The examination may reveal nonspecific features. However, individuals who are non-specialists may not recognize these features as indications of CS. Therefore, patients are often unaware of the potential complications associated with CS. This is consistent with the results of our study, in which patient-reported and physician-assessed manifestations were more consistent for hypertension and menstrual abnormalities than for other manifestations such as typical features, glucose metabolism impairment, and osteoporosis. This makes diagnosis challenging as non-specialist physicians and, more prominently, patients may not recognize the full range of symptoms associated with CS, especially the typical features with high diagnostic value. In addition, older patients diagnosed with CS present with a lower BMI and waist circumference than younger patients [37], and they typically do not exhibit symptoms commonly associated with CS such as skin alterations, depression, hair loss, hirsutism, and reduced libido. These findings may further complicate the diagnosis of CS in elderly patients.
By evaluating only the patient-reported manifestations, it appears that manifestations such as peripheral edema and proximal myopathy were more common. Possibly, these symptoms were not considered features of CS by physicians, in comparison to the degree of symptoms experienced by the patients. However, this may not necessarily imply diminishing the significance of the patient’s signs and symptoms, as these manifestations can be considered as the unidentified complaints and may result in a postponement of the diagnosis of CS. Patients may be experiencing symptoms that physicians do not perceive, indicating the importance of interview and physical examination. Further investigation is needed to elucidate underlying factors.
Considering the rarity of CS, it is crucial to suspect and diagnose the condition based on clinical symptoms and perform the appropriate screening tests without over- or under-screening [7]. Although CS screening in patients with diabetes mellitus and hypertension has been reported to lead to a diagnosis in only 0–0.7% and 0.1–0.5% of these patients, respectively [3841], it is ineffective in terms of false positives and cost [9]. Therefore, patients with typical features that are highly specific for CS, such as purple striae, easy bruising, and proximal myopathy [1812], as well as those with obesity, diabetes mellitus, or hypertension in combination with these features, should be screened for CS [727]. However, our results suggest that these symptoms are unlikely to be self-recognized. Therefore, the appropriate screening measures must be implemented to establish an early and effective diagnosis of CS.
In these situations, it is crucial for physicians to utilize their knowledge and experience to suspect CS based on symptoms such as typical features [10]. It has been reported that years of clinical experience in endocrine practice can contribute to the estimation of the pre-test probability of CS [16]. In contrast, non-specialists are less likely to encounter patients with CS in their lifetime, which can make it difficult to properly suspect CS [9]. From this perspective, it is of utmost importance that family physicians and general internists are knowledgeable regarding the manifestations that require screening for CS, as early diagnosis of this uncommon and severe condition is crucial [11]. Therefore, it is important for physicians who routinely treat patients presenting with common symptoms such as obesity, diabetes mellitus, and hypertension to meticulously interview and observe for any indicators of CS, even if the patient does not recognize them. Failure to adopt an appropriate tone in these situations may cause the disease to become undetectable.
In rare disorders such as CS, in addition to enhancing public recognition of the disease, the appropriate sharing of information and provision of specialized care in clinical practice remain important issues [42]. Early identification of such rare diseases can be achieved by promoting an understanding of the disease and its symptoms among family, friends, and patients who may be the first to recognize the signs and symptoms in an individual. In fact, in a questionnaire survey of 340 patients with CS across 30 countries, the diagnosis of CS was made in 5.6% of cases by the patients themselves and in 0.9% by their family or friends [43]. In the present study, we found that it took more than 3 years to diagnose CS in 58% of the cases. If CS and its symptoms are popularized among the public, the typical features of CS could be more readily reported to physicians and the time to diagnosis might be shorter. Furthermore, a primary care physician who is well-educated and knowledgeable is crucial in ensuring that the concerns of such individuals are not overlooked.
This study has some limitations. First, this single-center retrospective study included a relatively small sample size with few male patients. Second, CD and ACS have different pathologies; therefore, the frequencies of several CS-related manifestations will differ depending on their subtypes [344]. However, in this study, there was no difference in the discrepancies between patient-reported and physician-assessed manifestations in patients with CD or ACS. Nonetheless, it is crucial that comprehensive research is conducted in larger patient populations with a focus on employing methods that accurately reflect the pathophysiology of CD and ACS. Third, patient reports may be inaccurate in terms of onset and duration because they depend on the patient’s memory. Fourth, the endocrinologists who examined the patients differed, which may have affected the presence or absence of physician-assessed manifestations. Finally, this study investigated the differences between the manifestations reported by patients and those assessed by endocrinologists, although the evaluations conducted by primary care physicians, which are crucial for the early detection of CS, were not available. Future research is needed to investigate the differences in recognizing manifestations between non-specialist physicians and endocrinologists with extensive experience in CS and to examine the changes before and after education for these non-specialists to determine if they can lead to earlier diagnosis of CS.
In conclusion, endocrinologists have been shown to be aware of CS-related symptoms, especially typical features, whereas patients do not recognize these manifestations, even when the disease is severe. Therefore, the key to the early diagnosis and treatment of CS is a more proactive approach of questioning and examining patients suspected of having the disease.

Acknowledgements

We thank all the physicians and medical assistants who were involved in this study. We are grateful to all the laboratory members for their excellent discussions and fruitful suggestions. We also thank Editage (www.​editage.​jp) for English language editing.

Compliance with ethical standards

Conflict of interest

The authors declare no competing interests.

Ethics approval

This study conformed to the Declaration of Helsinki guidelines and was approved by the Ethics Committee of Kobe University Hospital (Approval No. 1351).
Informed consent was obtained from all the participants using an opt-out approach.
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Targeted analysis of Ubiquitin-Specific Peptidase (USP8) in a population of Iranian people with Cushing’s disease and a systematic review of the literature

Abstract

Objective

Activating mutation in Ubiquitin-specific peptidase (USP8) is identified to enhance cell proliferation and adrenocorticotropic hormone (ACTH) secretion from corticotroph pituitary adenoma. We investigated the USP8 variant status in a population of Iranian people with functional corticotroph pituitary adenoma (FCPA). Moreover, a systematic review was conducted to thoroughly explore the role of USP8 variants and the related pathways in corticotroph adenomas, genotype-phenotype correlation in USP8-mutated individuals with FCPA, and the potential role of USP8 and epidermal growth factor receptor (EGFR) as targeted therapies in PFCAs.

Methods

Genetic analysis of 20 tissue samples from 19 patients with PFCAs was performed using Sanger sequencing. Moreover, a systematic literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, web of Sciences, and Cochrane databases were searched. The last search was performed on 20 September 2023 for all databases.

Results

In our series, we found two somatic mutations including a 7-bp deletion variant: c.2151_2157delCTCCTCC, p. Ser718GlnfsTer3, and a missense variant: c.2159 C > G, p. Pro720Arg (rs672601311) in exon 14. The Systematic review indicated USP8 variant in 35% of corticotroph adenomas, with the highest frequency (25%) in 720 code regions, p. Pro720Arg. Data regarding the impact of USP8 mutational status on clinical characteristics and outcomes in FCPAs are inconsistent. Moreover, Pasireotide as well as inhibitors of EGFR such as Gefitinib and Lapatinib, as well as USP8 inhibitors including -ehtyloxyimino9H-indeno (1, 2-b) pyrazine-2, 3-dicarbonitrile, DUBs-IN-2, and RA-9 indicated promising results in treatment of corticotroph adenomas.

Conclusion

Although the USP8EGFR system has been identified as the main trigger and target of corticotroph tumorigenesis, more precise multicenter studies are required to yield more consistent information regarding the phenotype-genotype correlation and to develop effective targeted therapies.

Peer Review reports

Introduction

Pituitary corticotroph adenoma accounts for 68% of endogenous hypercortisolism [1]. Prolonged exposure to high cortisol levels is associated with a variety of long-term complications, impaired quality of life, and increased mortality [2]. Transsphenoidal surgical excision is the treatment of choice. However, curative surgery is challenging with the initial remission rate of 65–85% and a high recurrence rate [34].

The majority of functional corticotroph adenomas (FCAs) are sporadic. Although the genetic background is not well-established, potential candidate genes are proposed for tumor initiation and progression [5]. Hotspot mutations in ubiquitin-specific peptidase (USP8) are reported in 11–62% of sporadic corticotroph adenomas [6,7,8]. USP8 is a deubiquitinating enzyme that plays an important role in enhancing cell proliferation and regulating cell cycle [9]. The mutant USP8 was found to activate the epidermal growth factor receptor (EGFR) signaling pathway ultimately promoting adrenocorticotrophic hormone (ACTH) secretion [6]. Moreover, overexpression of EGFR and its signaling pathway components in pituitary corticotroph adenoma was reported [10]; and found to be positively associated with ACTH and cortisol levels as well as tumor recurrence [10]. These outcomes suggest that USP8 and EGFR are promising biomarkers for prediction of recurrence and can be used as targeted therapy.

Thus, we conducted a study to examine the USP8 and ubiquitin-specific peptidase 48 (USP48) variations in a group of Iranian people with Cushing’s disease (CD) and carried out a systematic review of the literature regarding the USP8/EGFR and their potential role in the clinical outcomes and targeted therapy in CD.

Methods

Case series

Study population

Paraffin-embedded blocks of pituitary tumor tissue from 19 patients with ACTH-secreting pituitary adenoma who underwent transsphenoidal surgery (TSS) between 2011 and 2019 were examined. The diagnosis of CD was based on clinical features and biochemical criteria [11]. The patients clinically suspected to CD were asked to collect urine free cortisol (UFC) in two separated times and underwent overnight dexamethasone suppression test (ODST). After confirmation of ACTH-dependent Cushing’s syndrome using measurement of ACTH level, a high-dose dexamethasone suppression test (HDDST) was performed to confirm the pituitary source of hypercortisolism. Patients with equivocal results or those with pituitary tumors less than 6 mm in size were undergone inferior petrosal sinus sampling (IPSS). Patient with clinical, biochemical, and radiological evidences of CD were undergone TSS. And eventually, corticotroph adenoma was confirmed using immunohistochemically staining of tumor tissue in all patients. The study was approved by the IUMS Research Ethics Committee (IR.IUMS.REC.1398.082). It was carried out under the declaration of Helsinki and the International Conference on Harmonization of Good Clinical Practice (ICH-GCP) guidelines, and informed consent was obtained from all patients.

DNA extraction and Sanger sequencing

A 10-µm thick section of formalin-fixed and paraffin-embedded (FFPE) tissue per sample was used for genomic DNA extraction. A molecular test was performed by amplification of USP8 and USP48 hotspot exons (exon 14 and exon 10, respectively) using conventional polymerase chain reaction (PCR). USP8 was amplified by two primer pairs; USP8_F1: AGCAGAATACTTTGGAGTGATTTC and USP8_R1: TTTGGAAGGTTCCCTATCCC with 251 bp product, USP8_F2: ACCCCTCCAACTCATAAAGC and USP8_R2: GAGTAGAAACTTTGAAATACAGCAC, with 220 bp product. A 240 bp fragment of USP48 was produced using; USP48_F: CCCGCTAAAGAATAAACAAACTC and USP48_R: GCATTCTAAAACATTTGCCTGC. PCR was done in 25 µl final volume (Ampliqon 2x PCR Mix) containing 0.5 µM of each primer and 30 ng of genomic DNA for 35 cycles (94 °C for 20 s, annealing 60 °C for 20 s and extension 72 °C for 20 s). The quality of PCR products was assessed by 2% agarose gel electrophoresis. Bidirectional Sanger sequencing was performed on an ABI DNA Analyzer (Applied Biosystems), The PCR primers were also used in the sequencing reaction. CodonCode Aligner software was used to analyze hotspot exome sequencing. Sequencing data quality was evaluated using Sanger electropherograms of both forward and reverse strands. The identified somatic mutations were analyzed in DNA taken from whole blood samples, but germline mutation was not detected.

Systematic review

Overview of the systematic literature review

We performed a systematic review of the literature to identify all published papers that reported the frequency of the USP8 variant and the related pathways in corticotroph pituitary adenomas, detailed clinical presentation and outcomes of patients with and without USP8 mutation and examined the USP8 and EGFR as targeted therapy.

Search strategy

We searched the PubMed, Scopus, web of Sciences, and Cochrane databases. The date of the last search was 20 September 2023 for all databases. We did not apply any language restrictions. Search terms included: “Cushing disease”, “Cushing’s disease”, “Corticotroph adenoma”, “Cushing adenoma”, “Client Cushing disease”, “Atypical corticotroph tumor”, “Corticotroph carcinoma”, “Normal pituitary”, “Corticotroph adenoma”, “Corticotroph Tumor”, “Pituitary ACTH Hypersecretion”, “ACTH-Secreting Pituitary Adenoma”, “Mutation”, “Germline mutation”, “Sporadic mutation”, USP8, “ubiquitin specific peptidase 8”, USP48, “ubiquitin specific peptidase 48”, “Epidermal growth factor”, EGF, “Epidermal growth factor receptor” EGFR, Biomarker.

Inclusion and exclusion criteria

All published papers including original articles, case reports, and case series were included in this systematic review provided that they have reported the frequency of USP8 variant or EGFR expression in corticotroph pituitary adenomas, compared the clinical presentation and outcomes of patients with and without USP8 variant, or examined USP8 or EGFR as treatment targets in CD. Studies applying any type of tissue namely resected human pituitary adenoma tissue, primary cell cultures, cell lines, and transfected cells were included. Articles were excluded if they included different types of pituitary tumors and did not separately analyze corticotroph adenomas, or if they were written in any language other than English.

Results

Case series

Baseline characteristics of the participants

This study included 19 patients of whom 63% (n = 12) were women. They aged between 17 and 65 years. Baseline cortisol ranged between 20 and 43 mic/dl. The ACTH level ranged between 34 and 164 pg/ml. The basal UFC ranged between 316 and 1153 mic/24 h. All patients presented with micro-adenoma except for two patients, one man and one woman (supplementary Table 1).

Frequency of USP8 gene variants

Sanger sequencing of 20 CD tumors revealed two heterozygous pathogenic variants in 2 samples: the 7-bp deletion variant, c.2151_2157delCTCCTCC, p. Ser718GlnfsTer3 was found in one patient; another patient showed the missense variant, c.2159 C > G, p. Pro720Arg (rs672601311) in exon 14. The pathogenic variants were found only in tumor tissue. Targeted sequencing (exon 10) of USP48 did not detect any pathogenic variant. The somatic variations in our study are in the catalytic conserved domain of USP8 protein and lead to disruption of the interaction between USP8 catalytic domain and 14-3-3 protein (Fig. 1).

Fig. 1

figure 1

Sanger sequencing of pathogenic variants in USP8 hotspot exon. (A, B) bi-directional sequencing of heterozygous missense variant, c.2159 C > G, in tissue sample, (C) A Sanger sequencing chromatogram of the blood sample detected no germline c.2159 C > G mutation. (D) Sanger sequencing chromatograms confirm the presence of heterozygous deletion (c.2151_2157delCTCCTCC) in tissue sample of patient II

Clinical outcomes after surgery

All patients achieved biochemical and structural cures after surgery except for one man and one woman who suffered from persistent disease because the tumors were not completely resected due to invasion into the cavernous sinus. They underwent radiotherapy after surgery. These two patients did not show the USP8 variant. Moreover, one man without evidence of the USP8 variant and the two women with the USP8 variant presented with recurrence after initial remission. They presented with micro-adenoma before surgery (supplementary Table 1).

Systematic review

The search yielded 1459 initial results. Upon removing the duplications (n = 410), 1049 studies were reviewed based on the relevancy of their titles and abstracts. Having excluded 957 articles, 92 studies were selected for full-text review. After an in-depth review, 31 articles were selected based on the inclusion and exclusion criteria. A PRISMA diagram detailing the search results is shown in Fig. 2.

Fig. 2
figure 2

Flow diagram of literature search and study selection

In this systematic review we extracted the information regarding the USP8 variant and the EGFR system in corticotroph adenomas. The USP8 variant was found in 460 individuals with FCPA accounting for 35% of the population included in the related published series (Table 1). Moreover, the highest frequency of missense mutation was found in the 720 code region, p.Pro720Arg (25%), followed by 19% in p.Ser718Pro (Fig. 3). In addition, the frequency of frame-shift and in-frame deletion observed in p.Ser718del and p.Ser719del was 12% and 11%, respectively (Fig. 3).

Table 1 Results of systematic literature review
Fig. 3

figure 3

Summary of USP8 mutations in patients with CD in selected studies

USP8 variants and the related pathways in corticotroph adenomas

In a study of 42 patients with corticotroph adenomas, USP8 variants were as follows: p. P720R (found in five patients), p. S718P (found in two patients), p. P720Q (found in two patients), p. S716Y (found in one patient), and p. S716F (found in one patient) [12]. Another genetic study demonstrated mutated USP8 deubiquitinating EGFR more effectively than wild type USP8. Some variants namely p.S718del, p.718SP, and p.P720R have higher deubiquitinated activity, while others including p.S718C, p.L713R, and p.Y717C showed similar activity compared to the wild type. These variants have been shown to increase the catalytic and proteolytic activity of USP8, which ultimately leads to the activation of the EGFR pathway. High EGFR levels, in turn, stimulate POMC gene transcription and increase plasma ACTH levels [6]. In the study of Seata, the USP8 variant was found in 23% of corticotroph adenomas. The variants were heterozygous, including p.S718, p.P720 (n = 18), p.S719del (n = 10), and p.P720_723 del (n = 1). Moreover, a comparison of 5 USP8 mutant vs. 34 wild-type specimens indicated different gene expression profile. According to the results, 2 genes involving in EGF signaling, CMTM8 (CKLFlike MARVEL transmembrane domain containing 8) and MAPK15 (mitogen-activated protein kinase 15), were upregulated in USP8 variant carriers [13]. Bujko et al. found USP8 mutation in 31.3% of patients with FCA and silent corticotroph adenomas (SCA). In-frame and missense mutations were p.Ser718del (7 patients), p.Pro720Arg (5 patients), p.Ser718Pro (2 patients) and p.Pro720Gln (one patient). USP8-mutated adenomas showed higher level of POMC, CDC25A, MAPK4 but lower level of CCND2, CDK6, CDKN1B than USP8-wild-type tumors [14].

Another study investigated the molecular pathogenesis of the spectrum of corticotroph adenomas, including CD, SCA, CCA (Crooke cell adenomas), and ACTH-producing carcinoma using whole exome sequencing. The patients with ACTH-producing carcinoma showed the highest number of variants in USP8, EGFR, TP53, AURKA, CDKN1A, and HSD3B1 genes. The USP8 variant was found in c.2159 C > G (p.Pro720Arg) and was positively correlated to the tumor size. However, the USP8 variant was not present in any of the patients with CD [15].

Martins and colleagues conducted a study to investigate the USP8 variant and its contribution to gene expression of cell cycle regulators including P27/CDKN1B, CCNE1, CCND1, CDK2, CDK4, and CDK6 in 32 corticotroph adenoma. They identified variants in certain hotspot exons, namely p.720R (found in five patients), p.S718del (found in three patients), p.S718P (found in one patient), and p.S719_T723del (found in one patient). Moreover, there was no difference regarding the gene expression of the cell cycle regulators CDKN1B (P27), CCNE1 (CYCLIN-E1), CCND1 (CYCLIN-D1), CDK2, CDK4, and CDK6 according to USP8 variant status [16]. Another study investigating the USP8 variants and genes involved in cell cycle regulation observed USP variants including p. P720R (n = 8), p.720Q (n = 2), p. S718SP (n = 2), and an in-frame deletion at the 719 position (n = 8). However, USP8-mutated tumors showed lower CDKN1B, CDK6, CCND2 and higher CDC25A expression. They also observed a significantly lower level of p27 in USP8-mutated tumors as compared to the wild-type ones [17].

A comprehensive study determined the presence of EGFR at the protein and mRNA levels in different pituitary adenomas. The highest incidence of EGFR expression was found in corticotroph adenomas. The corticotroph adenomas with EGFR expression did not show p27 immunoreactivity [18].

DNA methylation regulates promoter activities. The study by Araki et al. identified a novel regulatory region in the human POMC gene which functions as a second promoter. Moreover, they indicated that this region is highly methylated in SCAs and highly demethylated in FCAs and ectopic ACTH-secreting tumors. They also demonstrated demethylation of the second promoter is associated with aggressive features of FCAs independent of the USP8 variant or EGFR signaling. In contrast, the first promoter was highly demethylated in USP8-mutated FCAs [19]. Weigand et al. indicated that p27/kip1 protein expression significantly decreased in USP8-mutated adenomas compared to the wild-type USP8 tumors. Moreover, higher expression of heat shock protein 90 (HSP90) and an increase in the phosphorylation of the transcription factor CREB was observed in mutated-USP8 adenomas [20]. Achaete-scute complex homolog 1 (ASCL1) plays an important role in cell proliferation and also regulates POMC in the cell line. In a recent study, genetic analysis of corticotroph adenomas using RNA-seq and IHC showed an increase in ASCL1expression and protein levels in both mutated and wild type USP8 among CD patients [21].

Genotype-phenotype correlation in USP8-mutated individuals with functional corticotroph adenoma

Sanger sequencing of 120 FCPAs indicated the somatic USP8 variant more frequently in women than in men, which was associated with a significant lower size and higher ACTH level. Moreover, compared to the wild-type tumors, the USP8-mutated ones display a higher level of EGFR expression with a higher staining intensity. The initial remission rate and the recurrence rate in patients initially receiving remission were comparable in both groups [7]. Another study of patients with 134 functional and 11 silent corticotroph adenomas demonstrated somatic USP8 variants only in functional adenomas, none of them occurred in silent adenomas. The USP8 variant in adults was associated with lower age, and predominantly occurred in women. Moreover, the presence of USP8 variant was inversely associated with remission [22]. In a cohort of 42 pediatric patients with FCA, five different USP8 variants (three missenses, one frame-shift, and one in-frame deletion) were identified. None of the patients were found to have gremlin USP8 variants. Patients with somatic USP8 variant were significantly older than those with wild-type USP8. However, there was no significant difference in terms of preoperative hormonal profile and tumor invasiveness between the two groups. However, somatic USP8 mutated patients showed a higher rate of recurrence after a mean follow-up of 34.7 months [23].

In a cohort of 48 FCA, patients with the USP8 variant had significantly higher levels of preoperative urine-free cortisol (UFC). But there was no difference in preoperative ACTH and cortisol level between USP8-mutated and wild-type groups. Although initial remission rate was similar in both groups, patients with USP8 variant revealed a significantly higher rate of recurrence within 10 years follow-up, with a significantly shorter time to recurrence [24]. USP8-mutated FCA patients presented with a significantly larger size of adenoma in a retrospective study. But preoperative hormonal profile and the remission rate were similar in both groups [16]. Retrospective genetic analysis of 92 FCA patients indicated that the USP8 variant was significantly higher in women than men. There was no significant difference in preoperative hormonal profile and tumor size between USP8-mutated and wild-type groups. USP8-mutated carriers were more likely to achieve surgical remission. However, after 10 years follow-up, the recurrence rate was similar in the both groups [25]. A Retrospective study of patients with 30 functional and 20 silent corticotroph adenomas showed USP8 variants in 11 and 2 adenomas, respectively. There was no difference in sex, age, preoperative hormonal profile, and size of the adenomas between patients with and without USP8 variants. However, the USP8-mutated tumors revealed a higher rate of invasiveness. Furthermore, somatostatin receptor 5 (SSRT5) was more frequent in USP8-mutated adenomas [26]. In a retrospective study of FCA patients found no difference considering age at the presentation and hormonal profile between patients with and without USP8 variants. However, macro-adenoma was more frequently seen in USP8-mutated patients. Although initial remission rate was similar in the both groups, after a median 5 (2–8) years of follow-up, USP8-mutated carriers were more likely to develop recurrence [27]. The study conducted by Bujko et al., comparing patients with USP8 mutated and wild-type corticotroph adenomas, demonstrated no difference in age, sex, preoperative hormonal profile, tumor invasiveness, proliferation index, and histology (sparsely vs. densely granulation) between the two groups. However, the USP8-mutated patients showed a higher rate of remission [28].

A cohort of Asian-Indian patients with CD identified that there was no significant difference considering age, sex, tumor size, tumor invasion, and preoperative hormonal profile of the participants with and without the USP8 variant. Moreover, the initial remission rate and long-term recurrence, after a mean follow-up of 25.3 ± 13.6 months, were also comparable in both groups [29]. Liu et al. investigated the expression of EGFR and its signaling pathways in FCAs. They demonstrated that EGFR was overexpressed in 29 of 52 patients with FCA. Moreover, the EGFR signal transducing molecules p-EGFR, p-Akt and p-Erk were upregulated in EGFR-overexpressing adenomas but not in EGFR-negative adenomas. Moreover, the expression of EGFR was positively correlated with ACTH and cortisol levels but not with age, sex, or adenoma size. After a mean follow-up of 42.8 months, 22 patients had tumor recurrence. The EGFR expression was positively associated with the recurrence rate [10].

USP8 and EGFR as potential therapeutic targets in functional corticotroph adenoma

Our systematic search yields nine studies investigating the possible role of the USP8 variant in response to the medications. Four studies evaluated the presence of SSTR5 receptors in USP8– mutated tumors. Genetic analysis of FCAs from a cohort of 39 functional and 23 silent corticotroph adenoma indicated that there was no difference regarding the age of the participants, as well as hormonal profile, size, and invasiveness of the tumor between patients with and without USP8 variants. However, USP8-mutated adenomas showed significantly higher SSRT5 expression compared to the wild-type ones [26].

In a cohort study, USP8-mutated FCA patients were dominantly women and showed lower ACTH levels and smaller tumor size, but no difference in cortisol level. Remission rate was significantly higher in USP8-mutated patients compared to the wild-type ones. Moreover, USP8-mutated adenomas were more likely to express SSTR5 [30]. Genetic analysis of 51 FFPE tumors (21 USP8-mutated and 30 wild-type) indicated significantly higher SSTR5 immunoreactivity score in USP8-mutated tumors, regardless of mutation type. Moreover, in vitro study of 24 corticotroph tumors freshly obtained after TSS indicated a significantly better response to Pasireotide treatment, defined as suppression of ACTH secretion, in human corticotroph tumors carrying USP8 variants [31].

A more recent study aimed to investigate the impact of USP8 variants on in vitro response to Pasirotide in primary cultures obtained from 7 FCAs and also in murine corticotroph tumor cells. USP8 variant in both primary cultured cells and AtT20 cells was associated with higher SSTR5 expression. Moreover, this study indicated although associated with SSTR5 upregulation, mutations at the amino acid 718 of USP8 are not associated with a favorable response to pasireotide, whereas USP8 variants at the amino acid 720 might preserve pasireotide responsiveness [32].

Inhibition of EGFR using Gefitinib, a tyrosine kinase inhibitor, in surgically resected human and canine corticotroph cultured tumors suppressed expression of POMC. Moreover, Blocking EGFR activity in mice attenuated POMC expression, inhibited corticotroph tumor cell proliferation, and induced apoptosis [33]. Araki et al. conducted a study to investigate the utility of EGFR as a therapeutic target for CD. EGFR expression was observed by 2.5 months in transgenic (Tg) mice; and aggressive ACTH-secreting pituitary adenomas with features of Crooke’s cells developed by 8 months with 65% penetrance observed. Moreover, they used the EGFR tyrosine kinase inhibitor Gefitinib to confirm reversibility of EGFR effects on ACTH. Gefitinib suppressed tumor POMC expression and downstream EGFR tumor signaling. Plasma ACTH level and pituitary tumor size was significantly lower in Gefitinib group [34].

Another experimental study investigated the effect of Lapatinib, a potent tyrosine kinase inhibitor, on ACTH production and cell proliferation in AtT-20 mouse corticotroph tumor cells. Lapatinib inhibits EGFR. In this study, Lapatinib decreased proopiomelanocortin (POMC) mRNA levels and ACTH levels in AtT-20 cells and also inhibited cell proliferation and induced apoptosis. Inhibition of EGFR signaling contributes to the inhibition of ACTH production and cell proliferation in corticotroph adenomas [35].

The effect of a potent and selective Jak2 inhibitor, SD1029, on ACTH production and proliferation investigated in mouse AtT20 corticotroph tumor cells. They observed that Jak2 inhibitor SD1029 decreased both POMC transcript levels and basal ACTH levels. These in vitro experiments suggest the Jak2 inhibitor suppresses both the autonomic synthesis and release of ACTH in corticotroph tumor cells. SD1029 was also found to inhibit AtT20-cell proliferation. In addition, SD1029 decreased and increased PTTG1 and GADD45β transcript levels, respectively. They seem to contribute, in part, in the Jak2-induced suppression of cell proliferation and ACTH synthesis [36]. An experimental study examined the effect of USP8 inhibitor on EGFR expression level, and cell viability using AtT20 cells treated with 9-ehtyloxyimino9H-indeno (1, 2-b) pyrazine-2,3-dicarbonitrile, a synthesized USP8 inhibitor. This study demonstrated that treatment with USP8 inhibitor, 9‑ehtyloxyimino9H‑indeno(1,2‑b) pyrazine‑2,3 dicarbonitrile, suppresses ACTH secretion, cell viability, and promotes cell apoptosis in AtT20 cells suggesting that USP8 inhibitor could be a new therapeutic candidate for CD [37].

Kageyama et al. investigated the effects of a potent USP8 inhibitor, DUBs-IN-2, on ACTH production and cell proliferation in mouse corticotroph tumor (AtT-20) cells. DUBs-IN-2 decreased Proopiomelanocortin (POMC) mRNA and ACTH levels. Furthermore, DUBs-IN-2 decreased At-20 cell proliferation and induced apoptosis in corticotroph tumor cells [38]. Another study explored the potential effect of the USP8 inhibitor RA-9 on USP8-WT human tumor corticotroph cells and murine AtT-20 cells. RA-9 significantly decreased cell proliferation and increased cell apoptosis in AtT-20 cells. Moreover, RA-9 reduced ACTH release by USP8-mutant cells. The combined treatment with RA-9 and pasireotide resulted in more efficient in inhibiting ACTH secretion compared with RA-9 or pasireotide alone. Furthermore, similar to pasireotide, RA-9 was able to significantly reduce phospho- ERK1/2 levels in both AtT-20 cells and primary cultured cells from corticotropinomas [39].

Another study, investigating the USP8 variants and genes involved in cell cycle regulation, looked for the role of USP8 variants or a changed p27 level in the response to Palbociclib, Flavopiridol, and Roscovitine, in vitro, using murine corticotroph AtT-20/D16v-F2 cells. They did not found any significant difference in cell viability or cell proliferation between the AtT-20/D16v-F2 cells overexpressing wild-type and mutated USP8 that were treated with cell cycle inhibitors. There was also no difference in the response to inhibitors of CKDs in the cells with overexpression of p27 and control cells [17].

Analytical conclusion

In our series, we found two USP8 variants including a 7-bp deletion variant, c.2151_2157delCTCCTCC, p. Ser718GlnfsTer3, and a missense variant, c.2159 C > G, p. Pro720Arg (rs672601311) in exon 14. Moreover, the systematic review of the published data indicated that 35% of corticotroph adenomas harbor USP8 variant the most of which was found in the 720 code region, p. Pro720Arg. Similar to the most previous studies, the USP-8 mutated patients were women, presented with micro-adenoma and experienced recurrence after initial remission.

We systematically reviewed the literature regarding the USP8 variant in corticotroph adenomas and classified the results into three categories; including USP8 variants and the related pathways, genotype-phenotype correlation in USP8-mutated individuals, and USP8 and EGFR as potential therapeutic targets.

Different USP8 variants are identified in corticotroph adenomas. Activation of the EGFR pathway is a well-established consequence of USP8 variants [615]. But there is inconsistency regarding the role of USP8 variants in cell cycle regulation in corticotroph adenomas. Some studies showed no difference in the gene expression of the cell cycle regulators CDKN1B (P27), CCNE1 (CYCLIN-E1), CCND1 (CYCLIN-D1), CDK2, CDK4, and CDK6 according to USP8 variant status [21]; while the others indicated USP8-mutated tumors have lower CDKN1B, CDK6, CCND2 and higher CDC25A expression [20]. Moreover, demethylation of the first promoter is affected with USP8 variant status [19]. However, more studies are required to establish the pathway underlying the USP8 variants.

Data regarding sex, age, hormonal level, tumor size, and clinical outcomes in USP8-mutated individuals with FCA are relatively consistent among different studies. The USP8 variant seems to be associated with younger age and is more likely to occur in women. Meta-analysis of data from ten series indicated USP8 variant is 2.63 times higher in women than in men [40]. Since CD is more prevalent in young women, the potential effect of estrogen on the growth of USP8-mutant corticotroph cells has been hypothesized. There is evidence that corticotroph cells express estrogen receptors [41]. Moreover, in vitro studies indicated estrogen can stimulate corticotroph cell proliferation mediated by EGFR signaling pathways [42]. More precise studies are required to better explain the age-sex distribution of USP8 variant in patients with CD.

Results regarding the hormonal pattern among the series are partly controversial. Two series indicated significantly higher levels of ACTH and UFC in USP8-mutated patients compared to the wild-type ones [724]. Moreover, one study demonstrated the expression levels of EGFR were positively correlated with ACTH and cortisol levels [10]. Conversely, one study showed a significantly lower ACTH level in patients with the USP8 variant [30]. However, in a systematic analysis of the two series the correlation of UFC and USP8 variant did not reach a significant difference, this might be due to the small number of cases included in the analysis [40].

There are also some discrepancies on tumor size and invasiveness in USP8-mutated tumors. Some studies indicated a significant smaller size in USP8-mutated tumors, while others showed a significant larger size in USP8-mutated tumors. But some study found no significant difference regarding tumor size and invasiveness between USP8-mutated and wild-type tumors. A recent systematic analysis of magnetic resonance imaging (MRI) findings from individuals with CD indicated USP8-mutated tumors are more likely to be less than 10 mm compared to wild-type ones [40]. Moreover, a cohort of 60 patients with FCA indicated smaller tumor size and less invasiveness in USP8-mutated tumors [30]. In contrast to these findings, a cohort of Brazilian patients observed a tendency toward more somatic USP8 variant in tumors more than 10 mm in size [40]. These discrepancies might be due to the different methods used for extraction of MRI data.

Considering the clinical outcomes, most studies indicated a higher remission rate except for one that showed a significantly lower rate of remission in USP8-mutated patients [22252830]. Moreover, some studies demonstrated a higher rate of recurrence in carriers of USP8 variant [242742]. However, other studies found no significant difference neither in the initial remission nor in the late recurrence rate between the carriers of USP8 variant and the individuals with wild-type USP8. The inconsistency in the results might be due to the lack of a systematic protocol for evaluation of these patients. Moreover, the number of patients included in the different studies was relatively low. Further multicenter prospective studies with the same protocol are required to yield more consistent information regarding the influence of USP8 variant on the clinical presentation as well as early and late outcomes of FCAs.

There are promising studies regarding USP8-targeted therapy. We found evidence that USP8-mutated tumors have higher SSRT5 expression [3031]. Moreover, in vitro studies demonstrated that Pasirotide suppressed ACTH secretion significantly more in the USP8-mutated tumors than in wild-type ones [31]. These evidences suggest that USP8 mutational status could be used as a marker of Pasirotide response in CD. Furthermore, USP8-mutated tumors are more likely to express EGFRs compared to the wild-type ones [6]. Inhibition of EGFR using Gefitinib and Lapatinib has been associated with promising results regarding the EGFR-targeting therapy in CD [33,34,35]. Moreover, experimental studies of two USP8 inhibitors, 9‑ehtyloxyimino9H‑indeno (1,2‑b) pyrazine‑2,3 dicarbonitrile and DUBs-IN-2, have shown their potential to suppress POMC expression and ACTH secretion, decrease cell proliferation, and promote apoptosis [3738].

In summary, the studies investigated the association of USP8– variants and clinical manifestations as well as clinical outcomes of the corticotroph adenomas are partly inconsistent. More precise multicenter studies are required to yield more consistent information regarding the phenotype-genotype correlation and to develop effective targeted therapies.

Data availability

The datasets used and/or analyzed during the current atudy are available from the corresponding author on reasonable request.

Abbreviations

ABI:
Applied Biosystems
ACTH:
Adrenocorticotropic Hormone
CCA:
Crooke Cell Adenomas
CD:
Cushing’s Disease
DNA:
Deoxyribonucleic Acid
EGFR:
Epidermal Growth Factor Receptor
Erk:
Extracellular Signal-Regulated Kinases
FCAs:
Functional Corticotroph Adenomas
FCPA:
Functional Corticotroph Pituitary Adenoma
FFPE:
Formalin-Fixed And Paraffin-Embedded
ICH-GCP:
International Conference On Harmonization Of Good Clinical Practice
IHC:
Immunohistochemistry
MRI:
Magnetic Resonance Imaging
PCR:
Polymerase Chain Reaction
PRISMA:
Preferred Reporting Items For Systematic Reviews And Meta-Analyses
RNA-seq:
RNA Sequencing
SCA:
Silent Corticotroph Adenomas
TSS:
Transsphenoidal Surgery
USP8:
Ubiquitin-Specific Peptidase
USP48:
Ubiquitin Specific Peptidase 48

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Acknowledgements

We thank all the participants enrolled in this study.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Iran University of Medical Sciences No. IR.IUMS.REC.1398.082.

Author information

Author notes

  1. Nahid Hashemi-Madani and Sara Cheraghi are joint first authors.

Authors and Affiliations

  1. Endocrine Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences, Tehran, Iran, No. 10, Firoozeh St., Vali-asr Ave., Vali-asr Sq, Tehran, Iran

    Nahid Hashemi-Madani, Sara Cheraghi, Zahra Emami & Mohammad E. Khamseh

  2. Department of Pathology, Firoozgar hospital, Iran University of Medical Sciences, Tehran, Iran

    Ali Zare Mehrjardi

  3. Department of Endocrinology, Arad Hospital, Tehran, Iran

    Mahmoud Reza Kaynama

Contributions

Conception and design: NHM and MEK; Development of methodology: NHM, SC and ZE; Acquisition, analysis, and interpretation of data: NHM, SC, ZE and AZM; Writing, review, and/or revision of the manuscript: NHM, SC, ZE, MRK and MEK; Administrative, technical or, material support: NHM, MEK; Study supervision: MEK; All authors read and approved the final manuscript.

Corresponding author

Correspondence to Mohammad E. Khamseh.

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Ethics approval and consent to participate

This study was performed in accordance with the 1964 Helsinki Declaration, and was approved by the Ethics Committee of Iran University of Medical Sciences. Informed consent was obtained from all individual participants included in the study.

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Not applicable.

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The authors declare no competing interests.

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Hashemi-Madani, N., Cheraghi, S., Emami, Z. et al. Targeted analysis of Ubiquitin-Specific Peptidase (USP8) in a population of Iranian people with Cushing’s disease and a systematic review of the literature. BMC Endocr Disord 24, 86 (2024). https://doi.org/10.1186/s12902-024-01619-z

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Longterm-Outcomes In Patients With Cushing’s Disease vs. Non-Functioning Pituitary Adenoma After Pituitary Surgery: An Active-Comparator Cohort Study

Abstract

Objective

There is increasing evidence that multisystem morbidity in patients with Cushing’s disease (CD) is only partially reversible following treatment. We investigated complications from multiple organs in hospitalized patients with CD compared to patients with non-functioning pituitary adenoma (NFPA) after pituitary surgery.

Design

Population-based retrospective cohort study using data from the Swiss Federal Statistical Office between January 2012 and December 2021.

Methods

Through 1:5 propensity score matching, we compared hospitalized patients undergoing pituitary surgery for CD or NFPA, addressing demographic differences. The primary composite endpoint included all-cause mortality, major adverse cardiac events (i.e., myocardial infarction, unstable angina, heart failure, cardiac arrest, ischemic stroke), hospitalization for psychiatric disorders, sepsis, severe thromboembolic events, and fractures in need of hospitalization. Secondary endpoints comprised individual components of the primary endpoint and surgical reintervention due to disease persistence or recurrence.

Results

After matching, 116 patients with CD (mean age 45.4 years [SD, 14.4], 75.0% female) and 396 with NFPA (47.3 years [14.3], 69.7% female) were included and followed for a median time of 50.0 months (IQR 23.5, 82.0) after pituitary surgery. CD presence was associated with a higher incidence rate of the primary endpoint (40.6 vs. 15.7 events per 1,000 person-years, HR 2.75; 95% CI, 1.54 to 4.90). CD patients also showed increased hospitalization rates for psychiatric disorders (HR 3.27; 95% CI, 1.59 to 6.71) and a trend for sepsis (HR 3.15; 95% CI, 0.95 to 10.40).

Conclusions

Even after pituitary surgery, CD patients faced a higher hazard of complications, especially psychiatric hospitalizations and sepsis.

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Evaluating the usefulness of plasma chromogranin A measurement in cyclic ACTH-dependent Cushing’s syndrome

Abstract

Cushing’s syndrome, a clinical condition characterized by hypercortisolemia, exhibits distinct clinical signs and is associated with cyclic cortisol secretion in some patients. The clinical presentation of cyclic Cushing’s syndrome can be ambiguous and its diagnosis is often challenging.

We experienced a 72-year-old woman with cyclic ACTH-dependent Cushing’s syndrome caused by a pulmonary carcinoid tumor. Diagnosis was challenging because of the extended trough periods, and the responsible lesion was initially unidentified. A subsequent follow-up computed tomography revealed a pulmonary lesion, and ectopic ACTH secretion from this lesion was confirmed by pulmonary artery sampling. Despite the short peak secretion period of ACTH (approximately one week), immunostaining of the surgically removed tumor confirmed ACTH positivity. Interestingly, stored plasma chromogranin A levels were elevated during both peak and trough periods.

The experience in evaluating this patient prompted us to investigate the potential use of plasma chromogranin A as a diagnostic marker of ACTH-dependent Cushing’s syndrome. A retrospective study was conducted to determine the efficacy of plasma chromogranin A in three patients with ectopic ACTH syndrome (EAS), including the present case, and six patients with Cushing’s disease (CD) who visited our hospital between 2018 and 2021. Notably, plasma chromogranin A levels were higher in patients with EAS than in those with CD. Additionally, a chromogranin A level in the present case during the trough phase was lower than that in the peak phase, and was similar to those in CD patients. The measurement of plasma chromogranin A levels could aid in differentiating EAS from CD.

Keywords: ACTH-dependent Cushing’s syndromeCyclicCarcinoidPulmonary arterial samplingChromogranin A

From https://www.jstage.jst.go.jp/article/endocrj/advpub/0/advpub_EJ24-0128/_article