Epigenetic Mechanisms Modulated by Glucocorticoids With a Focus on Cushing Syndrome

Posted on April 19, 2024 by MaryO

Abstract

In Cushing syndrome (CS), prolonged exposure to high cortisol levels results in a wide range of devastating effects causing multisystem morbidity. Despite the efficacy of treatment leading to disease remission and clinical improvement, hypercortisolism-induced complications may persist. Since glucocorticoids use the epigenetic machinery as a mechanism of action to modulate gene expression, the persistence of some comorbidities may be mediated by hypercortisolism-induced long-lasting epigenetic changes. Additionally, glucocorticoids influence microRNA expression, which is an important epigenetic regulator as it modulates gene expression without changing the DNA sequence. Evidence suggests that chronically elevated glucocorticoid levels may induce aberrant microRNA expression which may impact several cellular processes resulting in cardiometabolic disorders.

The present article reviews the evidence on epigenetic changes induced by (long-term) glucocorticoid exposure. Key aspects of some glucocorticoid-target genes and their implications in the context of CS are described. Lastly, the effects of epigenetic drugs influencing glucocorticoid effects are discussed for their ability to be potentially used as adjunctive therapy in CS.

epigenetic, glucocorticoids, Cushing syndrome
Issue Section:

Mini-review

In Cushing syndrome (CS), adrenocorticotropic hormone (ACTH) hypersecretion by a pituitary adenoma or an ectopic source, or autonomous cortisol hypersecretion by an adrenal tumor, induces chronic endogenous hypercortisolism with loss of the cortisol circadian rhythm (1). CS is more prevalent in women than men and frequently occurs in the fourth to sixth decades of life (2).

Glucocorticoids (GC) have extensive physiological actions and regulate up to 20% of the expressed genome, mainly related to the immune system, metabolic homeostasis, and cognition. Therefore, the prolonged exposure to high cortisol levels results in a wide range of devastating effects, including major changes in body composition (obesity, muscle atrophy, osteoporosis), neuropsychiatric disturbances (impaired cognition, depression, sleep disturbances), the metabolic syndrome (obesity, hypertension, insulin resistance, and dyslipidemia), hypercoagulability, and immune suppression (3, 4). The consequences of hypercortisolism lead to compromised quality of life and increased mortality rate (5). The mortality rate in patients with CS is 4 times higher than the healthy control population (6). Risk factors such as obesity, diabetes, and hypertension contribute to the increased risk of myocardial infarction, stroke, and cardiac insufficiency. As a result, cardiovascular disease is the leading cause of the premature death in CS (5). Infectious disease is also an important cause of death in CS (5). Therefore, prompt treatment to control hypercortisolism is imperative to prevent complications and an increased mortality rate.

Despite the efficacy of treatment leading to disease remission, the clinical burden of CS improves, but does not completely revert, in every patient (7). Indeed, obesity, neuropsychiatric disturbances, hypertension, diabetes, and osteoporosis persist in a substantial number of biochemically cured patients. For instance, in a study involving 118 CS patients in remission for about 7.8 years (median), resolution of comorbidities such as diabetes occurred in only 36% of cases, hypertension in 23% of cases, and depression in 52% of the cases (8). It has been proposed that epigenetic changes as a consequence of hypercortisolism is a mechanism of the persistence of some comorbidities (9-12).

Epigenetics is a reversible process that modifies gene expression without any alterations in DNA sequence; frequently it is mediated by histone modification and DNA methylation together with microRNAs (13-15). GCs use the epigenetic machinery as a mechanism of action to regulate gene expression in physiological circumstances, such as metabolic actions and stress response. Its networks involve DNA and histone modifying enzymes, such as DNA methyltransferases (DNMTs), histone acetyltransferases (HATs), and histone deacetylases (HDACs) (16). (Fig. 1) The DNA methylation process catalyzed by DNMTs is usually associated with downregulation of gene expression (17). Histone modifications catalyzed by HAT enzymes induce gene transcription, while those by HDAC enzymes induce transcriptional repression (17). Drugs interfering with these enzymes (so-called epigenetic drugs) may affect the GC genomic actions confirming the interaction between GC and the epigenetic system (18, 19). Furthermore, GC can modulate HDAC and DNMT expression and activity (16, 19, 20). Based on these data it might be speculated that in CS, epigenetic modifications induced by long-term GC exposure plays a role in the development of the disease-specific morbidity (9, 10).

Figure 1.
Glucocorticoid (GC) and its epigenetic machinery. GC through its receptor interacts with DNA and histone modifying enzymes, such as DNA methyltransferases (DNMTs), histone acetyl transferases (HATs), and histone deacetylases (HDAC) to modulate gene expression.

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Glucocorticoid (GC) and its epigenetic machinery. GC through its receptor interacts with DNA and histone modifying enzymes, such as DNA methyltransferases (DNMTs), histone acetyl transferases (HATs), and histone deacetylases (HDAC) to modulate gene expression.

In this review we provide an overview of epigenetic aspects of GC action in physiological conditions and in the context of CS. We start with a detailed characterization of how GC, using the epigenetic system, can change chromatin structure in order to activate or silence gene expression. (Fig. 2) Subsequently, we describe the role of epigenetic mechanisms in the regulation of expression of several GC-target genes related to CS. Finally, we present the current evidence of epigenetic changes caused by the long-term of GC exposure and the potential use of epidrugs influencing GC actions.

Figure 2.
Epigenetic mechanisms of the glucocorticoid action to regulate gene expression. The GR is located in cytoplasm in a multi-protein complex; after GC binding, GR dissociates from the multi-protein complex, crosses the nuclear membrane, dimerizes, and binds to the GRE of the target gene. One of the mechanisms of action of GC is through the recruitment of co-regulators together with epigenetic enzymes, such as HAT, to change the chromatin structure, resulting in activation of gene transcription. Also, GR decreases gene expression by tethering other transcriptional factors and recruiting HDAC2, causing histone deacetylation, which leads to a repressed chromatin. GC can cause hypomethylation through downregulation in the expression of DNMT1. Abbreviations: Ac, acetylation; DNMT1, DNA methyltransferase 1; GC, glucocorticoid; GR, glucocorticoid receptor; GRE, glucocorticoid responsive elements; HAT, histone acetyltransferase; HDAC, histone deacetylases; Me: methylation.

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Epigenetic mechanisms of the glucocorticoid action to regulate gene expression. The GR is located in cytoplasm in a multi-protein complex; after GC binding, GR dissociates from the multi-protein complex, crosses the nuclear membrane, dimerizes, and binds to the GRE of the target gene. One of the mechanisms of action of GC is through the recruitment of co-regulators together with epigenetic enzymes, such as HAT, to change the chromatin structure, resulting in activation of gene transcription. Also, GR decreases gene expression by tethering other transcriptional factors and recruiting HDAC2, causing histone deacetylation, which leads to a repressed chromatin. GC can cause hypomethylation through downregulation in the expression of DNMT1. Abbreviations: Ac, acetylation; DNMT1, DNA methyltransferase 1; GC, glucocorticoid; GR, glucocorticoid receptor; GRE, glucocorticoid responsive elements; HAT, histone acetyltransferase; HDAC, histone deacetylases; Me: methylation.

Search Strategy

A search of the PubMed database was conducted using the advanced search builder tool for articles in the English language on the following terms “glucocorticoids,” “glucocorticoid receptor,” “Cushing,” “hypercortisolism,” “epigenetic,” “DNA methylation,” “histone deacetylase,” “histone acetyltransferase,” “microRNA” “fkbp5,” “clock genes,” and “POMC.” Moreover, references were identified directly from the articles included in this manuscript. The articles were selected by the authors after being carefully analyzed regarding their importance and impact.

Epigenetic Aspects of Genomic Action of Glucocorticoids

GCs regulate gene expression positively or negatively. GC-responsive genes include genes encoding for proteins associated with inflammation, metabolic processes, blood pressure and fluid homeostasis, apoptosis, cell cycle progression, circadian rhythm, and intracellular signaling (21).

The GC actions are cell type–specific (22). For instance, in an in vitro study, the comparison of GC-expressed genes between 2 cell lines, corticotroph (AtT20) and mammary (3134) cell lines, showed a different set of GC-regulated genes, revealing the cell type–specific nature of GC effects (23). GC function depends on the accessibility of glucocorticoid receptor (GR)-binding sites in the DNA of the target tissue, which in turn is mostly established during cell differentiation. Therefore, different chromatin organization explains the distinct GR-binding sites among different tissues (22, 24, 25). The chromatin accessibility is determined by histone modifications such as acetylation, methylation, phosphorylation, and/or DNA methylation, processes that are both dynamic and reversible (26).

Furthermore, gene expression is regulated in a GC-concentration-dependent manner which is tissue-specific. Only a few genes can be upregulated or downregulated at low concentrations of GC. For example, a dose of dexamethasone (Dex) as low as 0.5 nM selectively activated PER1 (period 1, transcription factor related to circadian rhythm) expression in lung cancer (A549) cells (21, 27). Additionally, continuous GC exposure or pulsed GC (cortisol fluctuation during circadian rhythm) may cause different responses with respect to gene expression (26, 28). For example, constant treatment with corticosterone induced higher levels of PER1 clock gene mRNA expression compared with pulsatile treatment, as demonstrated in an in vitro study using 3134 cell line (28).

The time course for gene expression in response to Dex is fast, with repression occurring slightly slower compared to activation. Half of activated and repressed genes are detected within, respectively, about 40 minutes and 53 minutes following Dex exposure (21).

In short, the transcriptional output in response to GC depends on cell type, as well as on the duration and intensity of GC exposure (21, 24, 26, 27). GCs act as a transcriptional regulatory factor resulting in activating or repressing the expression of genes. The GC exerts its function through binding to corticosteroid receptors, specifically, the mineralocorticoid receptor and the GR, members of the nuclear receptor superfamily (29, 30).

Glucocorticoid Receptor

The GR is located in the cytoplasm in a chaperone complex which includes heat-shock proteins (70 and 90) and immunophilins (such as FK506 binding protein [FKBP5]). Cortisol diffuses across the cell membrane and binds with high affinity to the GR. The activated GR bound to GC dissociates of the multi-protein complex and is transferred to the nucleus, where it ultimately regulates gene expression (26, 31).

GR is a transcription factor encoded by nuclear receptor subfamily 3, group C member 1 (NR3C1) gene, located in chromosome 5, and consisting of 9 exons. It is composed of 3 major functional domains, namely a DNA binding domain (DBD), the C-terminal ligand-binding domain (LBD) and the N-terminal domain (NTB). The LBD recognizes and joins the GC. NTB contains an activation function-1 (AF1) which connects with co-regulators and the members of the general transcription machinery to activate target genes. The DBD comprises 2 zinc fingers motifs that are able to identify and bind to glucocorticoid responsive elements (GREs) (32, 33).

GRα is the most expressed and functionally active GR. GRβ is another isoform which is the result of an alternative splicing in exon 9 of the GR transcript. The difference between the 2 isoforms is the distinct ligand-binding domain in GRβ. This variance prevents the GRβ from binding to GC. In fact, the GRβ counteracts GRα function by interfering with its binding to a GRE in the target gene, and GRβ expression is associated with GC resistance (32). In addition, GRβ has its own transcriptional activity which is independent and distinct from GRα (34).

Another splice variant of human GR, GRγ, is associated with GC resistance in lung cell carcinoma and childhood acute lymphoblastic leukemia (33, 35). There is an additional amino acid (arginine) in the DBD of the GRγ that reduces, by about half, the capacity to activate or suppress the transcription of the target gene, as compared with GRα (32). One study identified GRγ in a small series of corticotroph adenomas (36).

Glucocorticoid Mechanism of Action

The GR-GC complex induces or represses gene expression directly by binding to DNA, indirectly by tethering other transcription factors or yet in a composite manner that consists in binding DNA in association with binding to other co-regulators (35, 37).

The GR has the ability to reorganize the chromatin structure to become more or less accessible to the transcriptional machinery. In the classical mechanism of direct induction of gene expression, the GR dimerizes and binds to a GRE in DNA. The receptor recruits co-regulators, such as CREB binding protein, which has intrinsic histone acetyltransferase (HAT) activity that modifies the chromatin structure from an inactive to an active state. This model, called transactivation, upregulates the expression of some genes related to glucose, protein, and fat metabolism. Gene repression, on the other hand, is accomplished by GR binding to a negative GRE (nGRE) leading to the formation of a chromatin remodeling complex composed by co-repressor factors, such as NCOR1 and SMRT, and histone deacetylases (HDACs), that ultimately turn chromatin less accessible and suppress gene transcription. The gene repression through direct binding events occurs less frequently when compared to gene induction (25, 35, 38).

Another mechanism of GC action is through binding to other transcription factors (tethering). In case of switching off inflammatory genes, GR binds to transcriptional co-activator molecules, such as CREB binding protein with intrinsic HAT activity, and subsequently recruits HDAC2 to reverse histone acetylation, thus resulting in a suppression of the activated inflammatory gene (39). In the same model, GC interacts with other cofactors, such as the STAT family, to induce chromatin modifications resulting in increased gene expression (26).

Furthermore, the transcriptional dynamics of some genes follow a composite manner. In this model, GR, in conjunction with binding to GRE, also interacts with cofactors in order to enhance or reduce gene expression (35).

GCs can also modulate gene expression by influencing the transcription of epigenetic modifiers. An experimental study demonstrated that GC mediated the upregulation of HDAC2 in rats exposed to chronic stress, which in turn decreased the transcription of histone methyltransferase (Ehmt2) that ultimately upregulated the expression of Nedd4. Nedd4 is a ubiquitin ligase, expression of which has been related to cognitive impairment (40). Additionally, GC was found to interact with another epigenetic eraser, namely JMJD3, a histone demethylase, suppressing its transcription in endothelial cells treated with TNFα that led to decreased expression of other genes related to the blood-brain barrier (41).

GCs have the ability to induce (de)methylation changes in DNA, ultimately affecting gene expression. The DNA methylation process triggered by GC involves the family of DNA methyltransferases (DNMT) and ten-eleven translocation (TET) protein (20, 42-44). The DNMT, DNMT1, DNMT3A, and DNMT3B are able to transfer a methyl group to a cytosine residue in DNA, forming 5-methylcytosine (5mC), which negatively impacts gene expression. In contrast, TET protein chemically modifies the 5mC to form 5-hydroxymethylcytosine (5hmC), which ultimately leads to unmethylated cytosine, positively influencing gene expression (45).

Glucocorticoids mainly induce loss of methylation events rather than gain of methylation across the genome (11, 46). The DNA demethylation process can be either active or passive. The active mechanism is linked to the upregulation of TET enzyme expression that follows GC treatment, which was described in retinal and osteocyte cell line model studies (42, 43). The passive demethylation event involves the downregulation (Fig. 2) or dysfunction of DNMT1. DNMT1 is responsible for maintaining the methylation process in dividing cells (45). In case of GC exposure, GC can cause hypomethylation through downregulation in the expression of DNMT1, a process described in the AtT20 corticotroph tumor cell model, or through GC hindering DNMT activity, particularly DNMT1, as demonstrated in the retinal cell (RPE) line (20, 42, 44).

Glucocorticoid-Induced Epigenetic Changes

There are several molecular mechanisms connecting GR activation and epigenetic modifications ultimately affecting gene expression (Fig. 2). As described above, GC uses epigenetic machinery, such as DNA and histone modifying enzymes, to restructure the chromatin in order to induce or silence gene transcription (16, 47).

In an in vitro study using murine AtT20 corticotroph tumor and neuronal cell lines, after chronic GC exposure followed by a recovery period in the absence of GC, the cells retained an “epigenetic memory” with persistence of loss of methylation content in FKBP5 gene but with no increased gene expression at baseline. The functionality of this “epigenetic memory” only became evident in a second exposure to GC, when the cells responded sharply with a more robust expression of FKBP5 gene compared to the cells without previous exposure to GC (44). Another in vitro study, using a human fetal hippocampal cell line, confirmed long-lasting DNA methylation changes induced by GC. The cells were treated for 10 days with dexamethasone, during the proliferative and cell differentiation phases of the cell line, followed by 20 days without any treatment. The second exposure to GC resulted in an enhanced gene expression of a subset of GC-target genes (48). Additionally, using an animal model subjected to chronic stress, a distinct gene expression profile was demonstrated in response to acute GC challenge compared to those without chronic stress history. The proposed mechanism was that chronic stress resulted in GC-induced enduring epigenetic changes in target genes, altering the responsiveness to a subsequent GC exposure (49).

In general, it seems that the majority of differential methylation regions (DMRs) induced by GC are loss of methylation rather than gain of methylation. In an experimental study, an association between hypomethylation and GC exposure was demonstrated in mice previously exposed to high levels of GC. Further analysis demonstrated that the genes linked with DMR were mostly related to metabolism, the immune system, and neurodevelopment (11).

Human studies have also shown that excess of cortisol can induce modifications in DNA methylation. DNA methylation data obtained from whole blood samples from patients with chronic obstructive pulmonary disease (COPD) treated with GC revealed DMR at specific CpG dinucleotides across the genome. These DMR were confirmed by pyrosequencing and annotated to genes, such as SCNN1A, encoding the α subunit of the epithelial sodium channel, GPR97, encoding G protein coupled receptor 97, and LRP3, encoding low-density lipoprotein receptor-related protein 3 (50). Furthermore, it has been proposed that the negative impact of chronic GC exposure on the immune system, which increases the risk of opportunistically infections, may be epigenetically mediated (51). In a clinical study, using whole blood samples, an analysis of genome-wide DNA methylation was performed on patients before and after exposure to GC (51). Long-term GC exposure disrupts, through a persistent modification of the cytosine methylation pattern, the mTORC1 pathway which affects CD4+ T cell biology (51).

Taken together, these data clearly show the interplay between GC signaling and methylation and histone modifications processes suggesting that GC interferes in the epigenetic landscape modulating gene expression. It is possible that most of these GC-induced epigenetic events are dynamic and temporary, while others may persist leading to long-lasting disorders. Further research to provide insight into what makes some events reversible is warranted.

Epigenetic Changes as a Consequence of Long-Term Glucocorticoid Exposure in Cushing Syndrome

The comorbidities associated with CS are associated with increased mortality mainly due to cardiovascular events (52). GC-induced comorbidities in CS may be at least in part epigenetically mediated. Previous study using whole blood methylation profile demonstrated that specific hypomethylated CpG sites induced by GC were associated with Cushing comorbidities, such as hypertension and osteoporosis (46). The study identified a methylator predictor of GC excess which could be used as a biomarker to monitor GC status (46).

The long-term exposure to high cortisol levels may be crucial for the persistence of some morbidities in CS through epigenetic changes. Hypercortisolism-induced persistent changes in visceral adipose tissue gene expression through epigenetic modifications was investigated in a translational study (12). This study combined data from patients with active CS and data from an animal model of CS in active and remitted phase. Interestingly, the study demonstrated long-lasting changes in the transcriptome of adipose tissue that were associated with histone modifications induced by GC. Therefore, these epigenetic fingerprints observed even after the resolution of hypercortisolism may elucidate the mechanism of persistent modifications in gene expression in the visceral adipose tissue (12).

With regard to the persistence of GC-induced DMR, a genome-wide DNA methylation analysis showed a lower average of DNA methylation in patients in remission of CS compared to controls. Interestingly, the most common biologically relevant affected genes were retinoic acid receptors, thyroid hormone receptors, or hormone/nuclear receptors, important genes related to intracellular pathways and regulators of gene expression (9).

In summary, this large body of evidence supports the concept that prolonged GC exposure modulates the epigenetic landscape across the genome by inducing DMR and histone modifications. Some epigenetic modifications are persistent, and this may partially explain the incomplete reversibility of some of CS features following clinical remission.

Glucocorticoid-Target Genes in Cushing Syndrome

A detailed identification and characterization of GC-target genes may shed light in the understanding of the pathophysiology and treatment response in patients with CS. For instance, the GC regulation of pro-opiomelanocortin (POMC) expression as part of the physiologic GC negative feedback may be impaired in Cushing disease (CD), which is an important mechanism for the maintenance of high GC levels (53). Another example is the interaction between GC and clock genes, which may interfere in the loss of the GC circadian rhythm and may contribute to metabolic disorders in CS (54). Furthermore, the suppressive action of GC on drug targets, such as the somatostatin receptor (subtype 2), may influence the efficacy of first-generation somatostatin receptor ligands in normalizing cortisol levels in CD (55). Here we describe how GCs using epigenetic machinery influence the expression of important target genes and their implications in CS.

FKBP5

FK506 binding protein (FKBP5) plays an important role in the regulation of hypothalamic-pituitary-adrenal (HPA) system (56). As part of the GC negative feedback loop, GC binds to hypothalamic and pituitary GR. In the cytoplasm, GR is bound to a multi-protein complex including FKBP5. FKBP5 modulates GR action by decreasing GR binding affinity to GC and by preventing GR translocation from cytoplasm to nucleus (57, 58). In other words, an increase of FKBP5 expression is inversely correlated with GR activity and results in GC resistance leading to an impaired negative feedback regulation in the HPA axis (59).

FKBP5 is a GC-responsive gene; its upregulation by GC is part of an intracellular negative short-feedback loop (60). The mechanism by which GC regulates FKBP5 expression was shown to include inhibition of DNA methylation (44). In a model for CS, mice treated with corticosterone for 4 weeks had a reduced level of DNA methylation of FKBP5 in DNA extracted from whole blood, which was strongly correlated in a negative manner with GC concentration. Interestingly, a negative correlation was also observed between the degree of FKBP5 gene methylation measured at 4 weeks of GC exposure and the percentage of mice visceral fat (61). Accordingly, previous studies have provided compelling evidence of decreased methylation in the FKBP5 gene in patients with active CS compared to healthy control (10, 46). Even in patients with CS in remission, previous data have suggested a small decrease in FKBP5 methylation levels compared to healthy controls (9, 10). In an in vitro study, it was demonstrated that, by decreasing DNMT1 expression, GC is able to reduce FKBP5 methylation levels and, therefore, increase its expression (44).

Likewise, FKBP5 mRNA is also sensitive to GC exposure. A time-dependent increase in blood FKBP5 mRNA after single-dose prednisone administration has been demonstrated in healthy humans (62). Accordingly, patients with ACTH-dependent CS had higher blood FKBP5 mRNA levels compared with healthy controls, and after a successful surgery, FKBP5 mRNA returned to baseline levels (63). Furthermore, in another study, blood FKBP5 mRNA was inversely correlated with FKBP5 promoter methylation and positively correlated with 24-hour urine free cortisol (UFC) levels in patients with CS (46). Taken together, this fine-tuning of FKBP5 DNA methylation and mRNA according to the level of GC suggests that FKBP5 can be used as a biomarker to infer the magnitude of GC exposure.

POMC and Corticotropin-Releasing Hormone

The partial resistance of the corticotroph adenoma to GC negative feedback is a hallmark of CD. Indeed, the lack of this inhibitory effect constitutes a method to diagnose CD, that is, with the dexamethasone suppression test. One of the mechanisms related to the insensitivity to GC can be attributed to GR mutations which are, however, rarely found in corticotrophinomas (64). Another mechanism that was uncovered in corticotroph adenomas is an overexpression of the HSP90 chaperone resulting in reduced affinity of GR to its ligand and consequently GR resistance (53, 65).

In addition, the loss of protein expression of either Brg1, ATPase component of the SWI/SNF chromatin remodeling complex, or HDAC2 has been linked to GC resistance in about 50% of some adenomas (66). The trans-repression process on POMC transcription achieved by GC involves both the histone deacetylation enzyme and Brg1. One mechanism of corticotropin-releasing hormone (CRH)-induced POMC expression is through an orphan nuclear receptor (NR) related to NGFI-B (Nur77). NGFI-B binds to the NurRE sequence in the promoter region of POMC gene and recruits a co-activator to mediate its transcription. In a tethering mechanism, the GR directly interacts with NGFI-B to form a trans-repression complex, which contains the GR itself, Brg1, the nuclear receptor, and HDAC2; the latter being essential to block the gene expression through chromatin remodeling process (53, 66).

In CD, hypercortisolism exerts a negative feedback at CRH secretion from the hypothalamus (67). The mechanism involved in GR-induced suppression of CRH expression is through direct binding to a nGRE in the promoter region of CRH gene and subsequent recruitment of repressor complexes. In a rat hypothalamic cell line, it was demonstrated that Dex-induced CRH repression occurs through coordinated actions of corepressors involving Methyl-CpG-binding protein 2 (MeCP2), HDAC1, and DNA methyltransferase 3B (DNMT3B). Possibly, GR bound to nGRE recruits DNMT3B to the promoter in order to methylate a specific region, subsequently binding MeCP2 on these methylated sites followed by the recruitment of chromatin modify corepressor HDAC1, ultimately resulting in CRH suppression. Another possibility is that 2 independent complexes, one consisting of GR with DNMT3 for the methylation and the other the MeCP2, bound to methylated region, interact with HDAC1 to induce repression (68).

Clock Genes

The clock system and the HPA axis are interconnected regulatory systems. Cortisol circadian rhythm is modulated by the interaction between a central pacemaker, located in the hypothalamic suprachiasmatic nuclei, and the HPA axis (69). At the molecular level, mediators of the clock system and cortisol also communicate with each other, both acting as transcription factors of many genes to influence cellular functions.

In CS, the impact of chronic GC exposure on clock genes expression was recently evaluated using peripheral blood samples from patients with active disease compared with healthy subjects. The circadian rhythm of peripheral clock gene expression (CLOCK, BMAL, PER1-3, and CRY1) was abolished as a result of hypercortisolism, and that may contribute to metabolic disorders observed in Cushing patients (70). Another study, which investigated persistent changes induced by hypercortisolism in visceral adipose tissue, found that the expression of clock genes, such as PER1, remained altered in association with persistent epigenetic changes in both H3K4me3 and H3K27ac induced by hypercortisolism even after the resolution of hypercortisolism (12). This suggests that chronic exposure to GC may induce sustained epigenetic changes that can influence clock genes expression. Nevertheless, further studies are warranted to better elucidate how long-term exposure to GC impacts clock genes expression using the epigenetic machinery.

Glucocorticoid Effects on MicroRNAs

Along with histone modification and DNA methylation, microRNAs (miRNAs) have emerged as an epigenetic mechanism capable of impacting gene expression without changing DNA sequence (15). Interestingly, miRNA expression itself is also under the influence of epigenetic modifications through promoter methylation like any other protein-encoding genes (71).

MicroRNAs are small (about 20-25 nucleotides in length) non-coding RNAs that are important in transcriptional silencing of messenger RNA (mRNA). By partially pairing with mRNA, miRNAs can either induce mRNA degradation or inhibit mRNA translation to protein. MiRNAs regulate the translation of about 50% of the transcriptome, allowing them to play an important role in a wide range of biological functions, such as cell differentiation, proliferation, metabolism, and apoptosis under normal physiological and pathological situations. Some miRNAs can be classified as oncogenes or tumor suppressing genes, and aberrant expression of miRNAs may be implicated in tumor pathogenesis (71-73).

Insight into the regulation of miRNA expression is, therefore, crucial for a better understanding of tumor development and other human diseases, including cardiac, metabolic, and neurological disorders (73, 74). There are different regulatory mechanisms involved in miRNA expression, including transcriptional factors such as GR-GC. GC may modulate miRNA expression through direct binding to GRE in the promoter region of the host gene, as observed in hemopoietic tumor cells (75). In addition to transcriptional activation, in vascular smooth muscle cells, Dex treatment induces downregulation of DNMT1 and DNMT3a protein levels and reduces the methylation of miRNA-29c promoter, resulting in an increased expression of miRNA-29c (76). Interestingly, it was demonstrated that the increased expression of miRNA-29 family (miRNA-29a, -29b, and -29c) associates with metabolic dysfunction, such as obesity and insulin resistance, which pertains to CS (77, 78). With regard to metabolic dysfunction, miRNA-379 expression was shown to be upregulated by GC and its overexpression in the liver resulted in elevated levels of serum triglycerides associated with very low-density lipoprotein (VLDL) fraction in mice (79). In obese patients, the level of hepatic miRNA-379 expression was higher compared to nonobese patients and positively correlated with serum cortisol and triglycerides (79). Hence, GC-responsive miRNA may be, at least in part, a mediator to GC-driven metabolic conditions in CS.

In pathological conditions, such as seen in CS, prolonged exposure to an elevated cortisol level results in a wide range of comorbidities. It can be hypothesized that the chronic and excessive glucocorticoid levels may induce an aberrant miRNA expression that might impact several cellular processes related to bone and cardiometabolic disorders. A recent study addressed the impact of hypercortisolism on bone miRNA of patients with active CD compared to patients with nonfunctional pituitary adenomas. Significant changes in bone miRNA expression levels were observed, suggesting that the disruption of miRNA may be partially responsible for reduced bone formation and osteoblastogenesis (80). Similarly, altered expression levels of selected miRNAs related to endothelial biology in patients with CS may point to a contribution to a high incidence of cardiovascular disorders in Cushing patients (81). Therefore, dysregulated miRNAs as a consequence of high cortisol levels may underpin the development and progression of comorbidities related to CS. To the best of our knowledge, it is currently not clear whether miRNA dysregulation persists after resolution of hypercortisolism, thus contributing to the persistence of some comorbidities. This hypothesis needs to be further investigated.

MicroRNA can also be used as a diagnostic tool in CS. A study was performed to identify circulating miRNA as a biomarker to differentiate patients with CS from patients with suspected CS who had failed diagnostic tests (the control group) (82). It was observed that miRNA182-5p was differentially expressed in the CS cohort compared to the control group; therefore, it may be used as a biomarker (82). However, a large cohort is necessary to validate this finding (82). In corticotroph tumors, downregulation of miRNA 16-1 expression was observed relative to normal pituitary tissue (83). In contrast, the plasma level of miRNA16-5p was found to be significantly higher in CD compared to ectopic Cushing (EAS) and healthy controls (84). This finding suggests that miRNA16-5p may be a biomarker capable to differentiate the 2 forms of ACTH-dependent Cushing (84).

Epidrugs and Glucocorticoid Action in Cushing’s Syndrome

The interest in understanding the epigenetic mechanism of GC action in the context of CS is based on reversibility of epi-marks, such as DNA methylation and histone modifications, using epidrugs (85, 86). The biological characteristics of epigenetic drugs and their target have been extensively explored. Their effectiveness as antitumor drugs have been tested on corticotroph tumors using in vitro studies (87-89). However, a limited number of studies have explored the role of epidrugs as a therapeutic tool in reversing the genomic action of GC in CS, particularly in comorbidities induced by hypercortisolism (90, 91).

The use of histone deacetylase inhibitors (HDACi) may reduce the genomic action of GC (90-92). It has been demonstrated that the use of the HDAC inhibitor valproic acid increases the acetylation level of GR, consequently attenuating the genomic action of GC. In an experimental Cushing model in rats, the use of valproic acid decreased expression of genes related to lipogenesis, gluconeogenesis, and ion regulators in the kidney that ultimately reduces hepatic steatosis, hyperglycemia, and hypertension in ACTH-infused rats (90, 91).

More studies evaluating the effects of epidrugs influencing the GC actions are warranted to further elucidate the underlying mechanisms and to explore potential treatment modalities to reverse long-lasting consequences of chronic corticoid exposure.

Conclusions

In physiologic conditions, GC are secreted in pulses following a circadian rhythm pattern, as opposed to a constant, chronic, and high GC exposure in CS. This pathological pattern may account for numerous devastating effects observed in CS (7). Yet, the expressed genome in response to chronic GC exposure may potentially be abnormal, leading to dysregulation in clock genes, among other effects.

GC levels may return to a normal circadian pattern in response to a successful treatment, but with incomplete reversibility of some CS features, which may in part be explained by epigenetic changes. The epigenetic machinery is used by GC to induce dynamic changes in chromatin to modulate gene expression. (Fig. 2) It seems that most of chromatin modifications are reversible, but some may persist resulting in long-term epigenetic changes. (Table 1)

Table 1.

Evidence of interaction between glucocorticoid and epigenetic machinery

Epigenetic changes/epigenetic enzymes Action
Histone acetylation (HAT)

  • Glucocorticoid receptors (GR) recruit co-regulators, such as CREB binding protein (CBP), which has intrinsic histone acetyltransferase (HAT) activity that modifies the chromatin structure from an inactive to an active state (25, 33, 35).
Histone deacetylation (HDAC)

  • GR recruit histone deacetylases (HDACs) to turn chromatin less accessible and suppress gene transcription (25, 35).

  • The trans-repression process on POMC transcription achieved by glucocorticoids (GC) involves the histone deacetylation enzyme (HDAC2).

  • GC mediates the upregulation of HDAC2 in rats exposed to chronic stress (40).
Histone demethylase (JMJD3)

  • GC suppress transcription of JMJD3 in endothelial cells treated with TNFα (41).
Histone modifications

  • Using ChIP-seq, a study in mice treated for 5 weeks with corticosterone showed higher levels of histone modifications (H3K4me3, H3K27ac) compared to control mice. In mice after a 10-week washout period, persistence of this epigenetic fingerprint was observed, which was associated with long-lasting changes in gene expression (12).
DNA methylation (DNMT3B) and histone deacetylation (HDAC1)

  • GC mediates CRH downregulation through DNMT3B to the promoter in order to methylate a specific region and recruitment of chromatin modify corepressor HDAC (68).
DNA hypomethylation

  • GC induces downregulation of DNMT1 in AtT20 (mouse corticotroph adenoma cell line) (20).

  • GC induces upregulation of TET enzyme expression which was described in retinal and osteocyte cell line model (42, 43).

  • An experimental study in mice previously exposed to high levels of GC showed differentially methylated regions (DMR) induced by GC treatment, of which the majority was loss of the methylation (11).

  • Reduced DNA methylation in FKBP5 gene was found in patients in active disease and also in remission state of Cushing syndrome (CS) as compared to a healthy control group (10).

  • A genome-wide DNA methylation analysis showed a lower average of DNA methylation in patients in remission of CS compared to controls (9).

  • A study using whole blood methylation profile demonstrated an association between cortisol excess and DNA hypomethylation in patients with CS (46).
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Further studies are needed to elucidate how chronic exposure to GC leads to incomplete reversibility of CS morbidities via sustained modulation of the epigenetic machinery and possibly other mechanisms. Subsequent identification of therapeutic targets may offer new perspective for treatments, for example, with epidrugs, aiming to reverse hypercortisolism-related comorbidities.

Funding

The authors received no financial support for this manuscript.

Disclosures

T.P., R.A.F., and L.J.H. have nothing to declare.

Data Availability

Data sharing is not applicable to this article, as no datasets were generated or analyzed during the current study.

From https://academic.oup.com/jcem/advance-article/doi/10.1210/clinem/dgae151/7633538?searchresult=1

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Olfactory Neuroblastoma Causing Cushing’s Syndrome Due to the Ectopic Adrenocorticotropic Hormone (ACTH) Secretion

Posted on March 27, 2024 by MaryO

Abstract

Cushing’s syndrome is a constellation of features occurring due to high blood cortisol levels. We report a case of a 47-year-old male with a history of recurrent olfactory neuroblastoma (ONB). He presented with bilateral lower limb weakness and anosmia and was found to have Cushing’s syndrome due to high adrenocorticotropic hormone (ACTH) levels from an ectopic source, ONB in this case. Serum cortisol and ACTH levels declined after tumor removal.

Introduction

Olfactory neuroblastoma (ONB), or esthesioneuroblastoma, is a rare malignancy arising from neuroepithelium in the upper nasal cavity. It represents approximately 2% of all nasal passage tumors, with an incidence of approximately 0.4 per 2.5 million individuals [1]. ONB shares similar histological features with small round blue cell neoplasms of the nose. Ectopic hormone secretion is a very rare feature associated with these tumors. Five-year overall survival is reported to be between 60% and 80% [2,3]. The age distribution is either in the fifth to sixth decade of life [4,5], or in the second and sixth decades [6].

Features of Cushing’s syndrome (moon face, buffalo hump, central obesity hypertension, fragile skin, easy bruising, fatigue, muscle weakness) are due to high blood cortisol levels [7]. It can be either primary (cortisol-secreting adrenal tumor), secondary (adrenocorticotropic hormone (ACTH)-secreting pituitary tumor, also called Cushing disease), or ectopic ACTH secretion (from a non-pituitary source). All three types share similar features [8].

Ectopic ACTH syndrome (EAS) is due to an extra pituitary tumor, producing ACTH. It accounts for 12-17% of Cushing’s syndrome cases [9]. Most cases of EAS-producing tumors are in the lungs, mediastinum, neuroendocrine tumors of the gastrointestinal tract, and pheochromocytomas [9]. Ectopic ACTH secretion from an ONB is very rare. As of 2015, only 18 cases were reported in the literature [10]. Here, we report such a case.

Case Presentation

Our patient is a 47-year-old Bangladeshi male, with a history of recurrent ONB that was resected twice in the past (transsphenoidal resection in 2016 and 2019) with adjuvant radiotherapy, no chemotherapy was given. He also had diabetes mellitus type 1 (poorly controlled) and hypertension. He presented with bilateral lower limb weakness, anosmia, decreased oral intake, loss of taste for one week, and bilateral submandibular swelling that increased in size gradually over the past two years. There was no history of fever, cough, abdominal pain, or exposure to sick contacts. The patient reported past episodes of similar symptoms, but details are unclear. The patient’s family history is positive for diabetes mellitus type 1 in both parents. Lab tests in the emergency department showed hypokalemia and hyperglycemia as detailed in Table 1. He was admitted for further workup of the above complaints.

Test Patient Results Reference Range Unit Status
Hemoglobin 14.7 13-17 g/dL Normal
White blood cell (WBC) 17.9 4-10 10*9/L High
Neutrophils 15.89 2-7 10*9/L High
Lymphocytes 1.07 1-3 10*9/L Normal
Sodium 141 136-145 mmol/L Normal
Potassium 2.49 3.5-5.1 mmol/L Low (Panic)
Chloride 95 98-107 mmol/L Low
Glucose 6.52 4.11-5.89 mmol/L Elevated
C-reactive protein (CRP) 0.64 Less than 5 mg/L Normal
Erythrocyte sedimentation rate (ESR) 2 0-30 mm/h Normal
Creatinine 73 62-106 µmol/L Normal
Uric acid 197 202.3-416.5 µmol/L Normal
Alanine aminotransferase (ALT) 33.2 0-41 U/L Normal
Aspartate aminotransferase (AST) 18.6 0-40 U/L Normal
International Normalised Ratio (INR) 1.21 0.8-1.2 sec High
Prothrombin time (PT) 15.7 12.3-14.7 sec High
Lactate dehydrogenase (LDH) 491 135-225 U/L High
Thyroid-stimulating hormone (TSH) 0.222 0.27-4.20 mIU/L Low
Adrenocorticotropic hormone (ACTH) 106 ≤50 ng/L Elevated
Cortisol (after dexamethasone suppression) 1750 Morning hours (6-10 am): 172-497 nmol, Afternoon hours (4-8 pm): 74.1-286 nmol nmol/L Elevated (failure of suppression)
24-hour urine cortisol (after dexamethasone suppression) 5959.1 <120 nmol/24 hrs nmol/24hr Elevated (failure of suppression)
Table 1: Results of blood test at the time of hospitalization. Hypokalemia and high values of adrenocorticotropic hormone and cortisol were confirmed.

On examination, the patient’s vital signs were as follows: blood pressure was 154/77 mmHg, heart rate of 60 beats per minute, respiratory rate was 18 breaths per minute, oxygen saturation of 98% on room air, and a temperature of 36.7°C. The patient had a typical Cushingoid appearance with a moon face, buffalo hump, purple striae on the abdomen, central obesity, and hyperpigmentation of the skin. Submandibular lymph nodes were enlarged bilaterally. The examination of the submandibular lymph nodes showed a firm, fixed mass extending from the angle of the mandible to the submental space on the left side. Neurological examination showed weakness in both legs bilaterally (strength 3/5) and anosmia (checked by orthonasal smell test). The rest of the neurological exam was normal.

Laboratory findings revealed (in Table 1) a marked hypokalemia of 2.49 mmol/L and hyperglycemia of 6.52 mmol/L. The serum cortisol level was elevated at 1587 nmol/L. Serum ACTH levels were raised at 106 ng/L (normal value ≤50 ng/L). Moreover, the high-dose dexamethasone suppression test failed to lower the serum ACTH levels and serum and urine cortisol. Serum cortisol level after the suppression test was 1750 nmol/L, while 24-hour urine cortisol after the test was 5959.1 nmol/24hr. Serum ACTH levels after the test also remained high at 100mg/L. This indicated failure of ACTH suppression by high-dose dexamethasone, which points towards ectopic ACTH production. Other blood tests (complete blood count, liver function tests) were insignificant.

A computed tomography scan with contrast (CT scan) of the chest, abdomen, and pelvis, with a special focus on the adrenals, was negative for any malignancy or masses. CT scan of the neck showed bilaterally enlarged submandibular lymph nodes and an enlarged right lobe of the thyroid with nodules. Fine needle aspiration (FNA) of the thyroid nodules revealed a benign nature. Magnetic resonance imaging (MRI) of the brain showed a contrast-enhancing soft tissue lesion (18x18x10mm) in the midline olfactory groove area with extension into the frontal dura and superior sagittal sinus, suggesting recurrence of the previous ONB. There was evidence of previous surgery also. The pituitary gland was normal (Figures 1–2).

A-brain-MRI-(T1-weighted;-without-contrast;-sagittal-plane)-shows-a-soft-tissue-lesion-located-in-the-midline-olfactory-groove-area.-Dural-surface-with-extension-into-anterior-frontal-dura.
Figure 1: A brain MRI (T1-weighted; without contrast; sagittal plane) shows a soft tissue lesion located in the midline olfactory groove area. Dural surface with extension into anterior frontal dura.

MRI: Magnetic resonance imaging

A-brain-MRI-(T2-weighted;-without-contrast;-axial-plane)-shows-a-soft-tissue-lesion-located-in-the-midline-olfactory-groove-area.
Figure 2: A brain MRI (T2-weighted; without contrast; axial plane) shows a soft tissue lesion located in the midline olfactory groove area.

MRI: Magnetic resonance imaging

Octreotide scintigraphy showed three focal abnormal uptakes in the submandibular cervical nodes. Additionally, there was a moderate abnormal uptake at the midline olfactory groove with bilateral extension (Figure 3).

Whole-body-octreotide-scan-(15-mCi-99mTc-Octreotide-IV)-demonstrates-three-focal-abnormal-uptakes:-the-largest-(5.2-x-2.4-cm)-in-the-left-submandibular-region,-and-two-smaller-ones-on-the-right,-suggestive-of-lymph-node-uptake.-Additional-abnormal-uptake-was-seen-along-the-midline-of-the-olfactory-groove-region-with-bilateral-extension.-No-other-significant-abnormal-uptake-was-identified.
Figure 3: Whole-body octreotide scan (15 mCi 99mTc-Octreotide IV) demonstrates three focal abnormal uptakes: the largest (5.2 x 2.4 cm) in the left submandibular region, and two smaller ones on the right, suggestive of lymph node uptake. Additional abnormal uptake was seen along the midline of the olfactory groove region with bilateral extension. No other significant abnormal uptake was identified.

On microscopic examination, an excisional biopsy after the transcranial resection surgery of the frontal skull base tumor showed nests and lobules of round to oval cells with clear cytoplasm, separated by vascular and hyalinized fibrous stroma (Figures 4A–4B). Tumor cells show mild to moderate nuclear pleomorphism, and fine chromatin (Figure 4C). A fibrillary neural matrix is also present. Some mitotic figures can be seen. Immunohistochemical stains revealed positive staining for synaptophysin (Figure 4D) and chromogranin (Figure 4E). Stains for CK (AE1/AE3), CD45, Desmin, and Myogenin are negative. Immunostaining for ACTH was focally positive (Figure 4F), while the specimen of the cervical lymph nodes showed the same staining, indicating metastases. The cytomorphologic and immunophenotypic features observed are consistent with a Hyams grade II ONB, with ectopic ACTH production.

Histopathological-and-immunohistochemical-findings-of-olfactory-neuroblastoma.
Figure 4: Histopathological and immunohistochemical findings of olfactory neuroblastoma.

A (100x magnification) and B (200x magnification) – hematoxylin and eosin (H-E) staining shows cellular nests of round blue cells separated by hyalinized stroma. C (400x magnification) – nuclei show mild to moderate pleomorphism with fine chromatin. D (100x magnification) – an immunohistochemical stain for synaptophysin shows diffuse, strong cytoplasmic positivity within tumor cells. E (200x magnification) – tumor cells are positive for chromogranin. F (400x magnification) – ACTH cytoplasmic expression in tumor cells.

ACTH: adrenocorticotropic hormone

For his resistant hypokalemia, he had to be given intravenous (IV) and oral potassium chloride (KCL) repeatedly. The patient underwent transcranial resection of the frontal skull base tumor. The patient received cefazolin for seven days, and hydrocortisone for four days. After transcranial resection, his cortisol level decreased to 700 nmol/L. Furthermore, ACTH dropped, and serum potassium also normalized. Subsequently, the patient was transferred to the intensive care unit (ICU) for meticulous monitoring and continued care. In the ICU, the patient developed one episode of a generalized tonic-clonic seizure, which aborted spontaneously, and the patient received phenytoin and levetiracetam to prevent other episodes. A right-sided internal jugular vein and left transverse sinus thrombosis were also developed and treated with enoxaparin sodium. Following surgery, his low potassium levels improved, resulting in an improvement in his limb weakness. His other symptoms also gradually improved after surgery. Three weeks following the primary tumor resection, he underwent bilateral neck dissection with right hemithyroidectomy, for removal of the metastases. The patient opted out of chemotherapy and planned for an international transfer to his home country for further management. Other treatments that he received during hospitalization were ceftriaxone, azithromycin, and Augmentin®. Insulin was used to manage his diabetes, perindopril to regulate his blood pressure, and spironolactone to increase potassium retention. Omeprazole was administered to prevent GI bleeding and heartburn/gastroesophageal reflux disease relief after discharge.

Discussion

ONB was first described in 1924, and it is a rare neuroectodermal tumor that accounts for 2% of tumors affecting the nasal cavity [11]. Even though ONB has a good survival rate, long-term follow-up is necessary due to the disease’s high recurrence rate [2]. ONB recurrence has been approximated to range between 30% and 60% after successful treatment of the primary tumor [12]. Recurrent disease is usually locoregional and tends to have a long interval to relapse with a mean of six years [12]. The first reported case of ectopic ACTH syndrome caused by ONB was in 1987 by M Reznik et al., who reported a 48-year-old woman with ONB who developed a Cushing-like syndrome 28 months before her death [13].

The occurrence of Cushing’s syndrome due to ectopic ACTH can occur either in the initial tumor or even years later during its course or after recurrence [3,6,9,14]. Similar to the case of Abe et al. [3], our patient also presented with muscle weakness due to hypokalemia, which is a feature of Cushing’s syndrome. Hypokalemia is present at diagnosis in 64% to 86% of cases of EAS and is resistant to treatment [9,14], as seen in our case. In our patient, the exact time of development of Cushing’s syndrome could not be ascertained due to the non-availability of previous records. However, according to the patient, he started developing abdominal obesity, pigmentation, and buffalo hump in 2021 about two years after his second surgery for ONB.

The distinction between pituitary ACTH and ectopic ACTH involves utilizing CT/MRI of the pituitary, corticotropin-releasing hormone (CRH) stimulation test with petrosal sinus blood sampling, high dose dexamethasone suppression test, and checking serum K+ (more commonly low in ectopic ACTH) [2,15,16]. In our case, a CRH stimulation test was not available but CT/MRI brain, dexamethasone test, low serum potassium, plus the postoperative fall in cortisol levels, all pointed towards an ectopic ACTH source.

Conclusions

In conclusion, this case highlights the rare association between ONB and ectopic ACTH syndrome, which developed after tumor recurrence. The patient’s unique presentation of bilateral lower limb weakness and hypokalemia can cause diagnostic challenges, emphasizing the need for comprehensive diagnostic measures. Surgical intervention proved crucial, with postoperative cortisol values becoming normal, highlighting the efficacy of this approach. The occurrence of ectopic ACTH production in ONB patients, although very rare, is emphasized, so that healthcare professionals who deal with these tumors are aware of this complication. This report contributes valuable insights shedding light on the unique ONB manifestation causing ectopic ACTH syndrome. The ongoing monitoring of the patient’s clinical features will further enrich the understanding of the course of this uncommon phenomenon in the medical literature.

References

  1. Thompson LD: Olfactory neuroblastoma. Head Neck Pathol. 2009, 3:252-9. 10.1007/s12105-009-0125-2
  2. Abdelmeguid AS: Olfactory neuroblastoma. Curr Oncol Rep. 2018, 20:7. 10.1007/s11912-018-0661-6
  3. Abe H, Suwanai H, Kambara N, et al.: A rare case of ectopic adrenocorticotropic hormone syndrome with recurrent olfactory neuroblastoma. Intern Med. 2021, 60:105-9. 10.2169/internalmedicine.2897-19
  4. Yin Z, Wang Y, Wu Y, et al.: Age distribution and age-related outcomes of olfactory neuroblastoma: a population-based analysis. Cancer Manag Res. 2018, 10:1359-64. 10.2147/CMAR.S151945
  5. Platek ME, Merzianu M, Mashtare TL, Popat SR, Rigual NR, Warren GW, Singh AK: Improved survival following surgery and radiation therapy for olfactory neuroblastoma: analysis of the SEER database. Radiat Oncol. 2011, 6:41. 10.1186/1748-717X-6-41
  6. Elkon D, Hightower SI, Lim ML, Cantrell RW, Constable WC: Esthesioneuroblastoma. Cancer. 1979, 44:3-1087. 10.1002/1097-0142(197909)44:3<1087::aid-cncr2820440343>3.0.co;2-a
  7. Nieman LK, Biller BM, Findling JW, Newell-Price J, Savage MO, Stewart PM, Montori VM: The diagnosis of Cushing’s syndrome: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2008, 93:1526-40. 10.1210/jc.2008-0125
  8. Chabre O: Cushing syndrome: physiopathology, etiology and principles of therapy [Article in French]. Presse Med. 2014, 43:376-92. 10.1016/j.lpm.2014.02.001
  9. Isidori AM, Lenzi A: Ectopic ACTH syndrome. Arq Bras Endocrinol Metabol. 2007, 51:1217-25. 10.1590/s0004-27302007000800007
  10. Kunc M, Gabrych A, Czapiewski P, Sworczak K: Paraneoplastic syndromes in olfactory neuroblastoma. Contemp Oncol (Pozn). 2015, 19:6-16. 10.5114/wo.2015.46283
  11. Finlay JB, Abi Hachem R, Jang DW, Osazuwa-Peters N, Goldstein BJ: Deconstructing olfactory epithelium developmental pathways in olfactory neuroblastoma. Cancer Res Commun. 2023, 3:980-90. 10.1158/2767-9764.CRC-23-0013
  12. Ni G, Pinheiro-Neto CD, Iyoha E, et al.: Recurrent esthesioneuroblastoma: long-term outcomes of salvage therapy. Cancers (Basel). 2023, 15:1506. 10.3390/cancers15051506
  13. Reznik M, Melon J, Lambricht M, Kaschten B, Beckers A: Neuroendocrine tumor of the nasal cavity (esthesioneuroblastoma). Apropos of a case with paraneoplastic Cushing’s syndrome [Article in French]. Ann Pathol. 1987, 7:137-42.
  14. Kadoya M, Kurajoh M, Miyoshi A, et al.: Ectopic adrenocorticotropic hormone syndrome associated with olfactory neuroblastoma: acquirement of adrenocorticotropic hormone expression during disease course as shown by serial immunohistochemistry examinations. J Int Med Res. 2018, 46:4760-8. 10.1177/0300060517754026
  15. Clotman K, Twickler MTB, Dirinck E, et al.: An endocrine picture in disguise: a progressive olfactory neuroblastoma complicated with ectopic Cushing syndrome. AACE Clin Case Rep. 2017, 3:278-83. 10.4158/EP161729.CR
  16. Chung YS, Na M, Ku CR, Kim SH, Kim EH: Adrenocorticotropic hormone-secreting esthesioneuroblastoma with ectopic Cushing’s syndrome. Yonsei Med J. 2020, 61:257-61. 10.3349/ymj.2020.61.3.257

From https://www.cureus.com/articles/226080-olfactory-neuroblastoma-causing-cushings-syndrome-due-to-the-ectopic-adrenocorticotropic-hormone-acth-secretion-a-case-report?score_article=true#!/

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Cushing Syndrome due to a CRH- and ACTH-Secreting Silent Pheochromocytoma

Posted on February 26, 2024 by MaryO

Highlights

  • EAS should be considered in patients presenting with rapid progression of ACTH-dependent hypercortisolism causing severe clinical and metabolic abnormalities.
  • Ectopic ACTH secretion by a pheochromocytoma should be suspected in cases of ACTH-dependent Cushing syndrome in the presence of an adrenal mass.
  • If required, medical management with steroidogenesis inhibitors can be initiated at the time of EAS diagnosis to control clinical and metabolic derangements associated with severe hypercortisolemia
  • In patients with ACTH-dependent Cushing syndrome from an ectopic source, inhibiting steroidogenesis should be reserved for cases where the initial diagnosis is unclear or patients who are not suitable candidates for surgery.
  • Unilateral adrenalectomy is indicated in the management of ACTH/CRH-secreting pheochromocytomas and is typically curative.
  • Catecholamine blockade should be started prior to surgical removal of catecholamines-secreting pheochromocytomas.
  • A multidisciplinary approach is required to diagnose and manage this condition.

Abstract

Background/Objective

Ectopic co-secretion of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) in silent (i.e., noncatecholamine-secreting) pheochromocytoma is a rare cause of Cushing Syndrome (CS).

Case Report

A 57-year-old woman rapidly developed hypercortisolism, clinically manifesting as fatigue, muscle weakness, weight gain, and worsening hypertension, and biochemically characterized by hypokalemia and marked elevation of serum cortisol and plasma ACTH. This acute presentation suggested a diagnosis of ectopic ACTH syndrome (EAS). Imaging studies revealed a right adrenal mass that enhanced after administration of the radioisotope 68Ga-DOTATATE. Plasma metanephrines were normal in two separate measurements. The possibility of a silent pheochromocytoma was considered. After controlling her hypercortisolism with metyrapone and surgical preparation with alpha blockade, the patient underwent elective right adrenalectomy. Pathology revealed a pheochromocytoma that stained focally for ACTH and CRH. Postoperatively, cortisol levels normalized, the hypothalamic–pituitary–adrenal (HPA) axis was not suppressed, and clinical symptoms from hypercortisolism abated.

Discussion

Patients who exhibit a rapid progression of ACTH-dependent hypercortisolism should be screened for ectopic ACTH syndrome (EAS). The use of functional imaging radioisotopes (such as gallium DOTA-peptides), improves the detection of ACTH-secreting tumors. Preoperative treatment with steroidogenesis inhibitors helps control clinical and metabolic derangements associated with severe hypercortisolemia, while alpha blockade prevents the onset of an adrenergic crisis.

Conclusion

We present a rare case of EAS due to a silent pheochromocytoma that co-secreted ACTH and CRH. Pheochromocytoma should be considered in patients with EAS who have an adrenal mass even in the absence of excessive catecholamine secretion.

Key words

ectopic ACTH syndrome
Cushing Syndrome
non-catecholamine-secreting pheochromocytoma

Abbreviations

EAS

ectopic ACTH syndrome
CS

Cushing Syndrome
CRH

corticotropin-releasing hormone
ACTH

adrenocorticotropic hormone
DHEA-S

dehydroepiandrosterone sulfate
UFC

urine free cortisol
PRA

plasma renin activity

Introduction

Cushing Syndrome (CS) is rare, with an estimated incidence of 0.2-5.0 per million people per year, and prevalence of 39-79 per million (1). Ectopic ACTH Syndrome (EAS), a type of CS originating from extra-pituitary ACTH-secreting tumors, is uncommon. The prevalence of CS due to ACTH-secreting adrenal medullary lesions is not well established. However, EAS is observed in approximately 1.3% of all identified cases of pheochromocytoma (2). Recognizing EAS can be challenging due to its rarity, leading to delayed diagnosis.

Neuroendocrine neoplasms can produce CRH, which can lead to the secretion of ACTH by the pituitary. In certain cases, co-secretion of ACTH and CRH by an adrenal neoplasm has been observed. Only two published cases have provided definitive biochemical and immunohistochemical evidence of exclusive CRH secretion (3).

Case Report

A 57-year-old woman with a history of well-controlled hypertension sought care due to a two-month history of 60 lb weight gain, facial rounding, easy bruising, muscle weakness, lower extremity edema and acne. Her blood pressure control had worsened, and laboratory tests showed a markedly low serum potassium level of 1.8 mmol/L while taking hydrochlorothiazide. To manage her blood pressure, she was prescribed a calcium channel blocker, an angiotensin receptor blocker, and potassium supplements. However, her symptoms worsened, and she was referred to our emergency department. Blood pressure at presentation to our hospital was 176/86 mmHg. She had characteristic features of CS, including face rounding, supraclavicular fullness, dorsocervical fat accumulation, pedal edema, oral candidiasis, multiple forearm ecchymoses, and acneiform skin eruptions. No visible abdominal striae were present. She had no family history of pheochromocytoma, or multiple endocrine neoplasia type 2.

Serum cortisol level was 128 mcg/dL (normal range: 4.6-23.4) at 5 PM, with an ACTH level of 1055 pg/mL (normal range: 6-50); serum DHEA-S level was elevated at 445 mcg/dL (normal range: 8-188). Her 24-hour urine cortisol was at 12,566 mcg (normal range: 4.0-50.0). Plasma metanephrines were normal at <25 pg/mL (normal range: <57), and plasma normetanephrine was 44 (normal range: <148). A second plasma metanephrine measurement showed similar results. Serum aldosterone level and plasma renin activity were low at 2 ng/dL (normal range: 3-16) and 0.11 ng/mL/h (normal range: 0.25-5.82), respectively. Dopamine and methoxytyramine levels were not measured. An abdominal CT revealed a 4.8 x 4.5 x 5 cm right heterogeneously enhancing adrenal mass with a mean Hounsfield Unit of 68 in the non-contrast phase, and an absolute percentage washout of 30% (Fig 1A). The left adrenal gland appeared hyperplastic (Fig 1B). An Octreoscan, which was the in-hospital available nuclear medicine imaging modality, confirmed a 5.1 cm adrenal mass that was mild to moderately avid, with diffuse bilateral thickening of the adrenal glands and no other focal radiotracer avidity. A pituitary MRI did not show an adenoma, and EAS was suspected. Further evaluation with 68Ga-DOTATATE PET/CT (Fig 2) performed after her admission demonstrated an avid right adrenal mass consistent with a somatostatin receptor-positive lesion. No other suspicious tracer uptake was detected. These findings were consistent with a neuroendocrine tumor, such as pheochromocytoma.

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Fig. 1. Preoperative abdominal computed tomography scan showing a 4.8 x 4.5 x 5 cm right heterogeneously enhancing adrenal mass with irregular borders (A) and a hyperplastic left adrenal gland (B).

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Fig 2. 68Ga-DOTATATE PET/CT showing an avid right adrenal mass.

To control her symptoms while undergoing workup, the patient received oral metyrapone 500 mg thrice daily and oral ketoconazole 200 mg twice daily. Ketoconazole was stopped due to an increase in transaminases. The dosage of metyrapone was increased to 500 mg four times daily and later decreased to alternating doses of 250 mg and 500 mg four times daily. Within 3 weeks of starting medical therapy, serum cortisol level normalized at 20 mcg/dL. The 24-hour UFC improved to 246.3 mcg/24h. She experienced gradual improvement in facial fullness, acne, and blood pressure control.

The possibility of a silent pheochromocytoma was considered, and a-adrenergic blockade with doxazosin 1 mg daily was started 1 month prior surgery. She underwent surgery after two months of metyrapone therapy. With an unclear diagnosis and a large, heterogeneous adrenal mass, the surgical team elected to perform open adrenalectomy for en bloc resection due to concerns for an adrenal malignancy. The tumor was well-demarcated and did not invade surrounding structures (Figure 3A). H&E-stained sections showed classic morphologic features of a pheochromocytoma (Figure 3B), with immunohistochemistry demonstrating strong immunoreactivity for synaptophysin and chromogranin, and negative SF- I and inhibin stains excluding an adrenal cortical lesion. The sections analyzed by QuPath (4) revealed that approximately 4% of ce11s were ACTH cells, often found in isolation, and had a clear, high signal-to-noise staining (Figure 3C). CRH cells were less prevalent, comprising about 2.4% of the total analyzed cells, and tended to cluster together (Figure 3D). These cells had more background staining, resulting in a lower signal- to-noise ratio.

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Figure 3. Gross and Histopathological analysis of the patient’s pheochromocytoma. (A) Image of the gross excised specimen. (B) H&E staining (200x final magnification) demonstrates prominent vascularity and cells with finely granular, eosinophilic cytoplasm and salt-and-pepper chromatin. (C) ACTH staining (200x final magnification) shows clear and isolated positive cells, representing about 4.0% of the section analyzed by QuPath. (D) CRH staining (200x final magnification) reveals tight clusters of positive cells, accounting for 2.4% of the total cells. Positive (human placenta and hypothalamus) and negative (thyroid gland) control tissues performed as expected (data not shown).

The patient’s postoperative recovery was uneventful, with a short course of hydrocortisone which was stopped 1 week after surgery after HPA axis evaluation showed normal results. After one month, hypercortisolism had resolved, as shown by a normal 24-hour UFC at 28 mcg.

Administration of dexamethasone at 11 PM resulted in suppression of morning cortisol to 0.8 and 0.6 mcg/dL 1 and 7 months after surgery, respectively. Her liver function tests normalized, and blood pressure was well-controlled with amlodipine 10 mg daily and losartan 100 mg daily. Genetic testing for pheochromocytoma predisposition syndromes is currently planned.

Discussion

EAS accounts for 10-20% of cases of ACTH-dependent CS (5). This condition can be caused by several neuroendocrine neoplasms that produce bioactive ACTH (6) In the literature, we have found 99 documented cases of EAS caused by a pheochromocytoma. Of these, 93% showed ACTH expression. Only two cases have been reported with dual staining of ACTH and CRH (7). Exclusive CRH production has only been reported in two cases (8:9). However, the true prevalence of CRH-producing pheochromocytomas might be underestimated, as most cases testing for CRH expression was not performed.

Although the clinical presentation of EAS may be highly variable, there is often a rapid onset of hypercortisolism accompanied by severe catabolic symptoms. The diagnostic process should focus on identifying the location of a potential neuroendocrine neoplasm responsible for the ACTH secretion. Sometimes the peripheral origin of ACTH must be confirmed by inferior petrosal sinus sampling (IPSS). In this case, given the clinical presentation consistent with EAS, negative pituitary MRI, and the presence of an adrenal mass that needed to be removed independently, IPSS was not performed.

Neuroendocrine neoplasms express somatostatin receptors on their surface, which allow functional imaging using [11 lln]-pentetreotide (Octreoscan). However, Octreoscan has a low sensitivity in detecting occult EAS. In cases where the tumor is in the abdomen and pelvis, Octreoscan has limited utility in locating the source of ACTH (10). This increased risk of false negatives is caused by physiological tracer uptake by the liver, spleen, urinary tract, bowel, and gallbladder. The use of Gallium-68 labeled somatostatin receptor ligands (PET/CT 68Ga-DOTATATE) is more effective in detecting somatostatin receptors (SSTR2) than [11lln]-pentetreotide due to its higher spatial resolution and affinity (11)_ This test was performed after discharge form the hospital to rule out the presence of a second, smaller neuroendocrine tumor that the Octreoscan might have missed. A new molecular imaging technique targeting CRH receptors (68Ga CRH PET/CT) has shown potential in identifying tumors expressing CRH, but its availability remains limited (12). In our patient’s case, both the Octreoscan and 68Ga- DOTATATE successfully identified the adrenal tumor as a potential ACTH/CRH secretion source.

According to relevant guidelines, presurgical adrenergic blockade is recommended for patients with biochemical evidence of catecholamine excess (13, 14). Conversely, silent pheochromocytomas can generally be operated without alpha blockade (15). Despite this, we opted to administer pre-operative alpha blockade as a precautionary measure for this patient.

Pathology examination confirmed the diagnosis of pheochromocytoma. ACTH and CRH staining demonstrated that clear and significant populations of two separate ACTH and CRH positive cells were present in the excised pheochromocytoma. ACTH/CRH cells were dispersed throughout various regions of the pheochromocytoma rather than being well-defined, separate histological entities. As a result, there is no indication that this resulted from collision tumors, but rather random mutation and expansion of tumor cells into ACTH or CRH secreting cells. These results have limitations, including variation in ACTH and CRH expressing regions due to tumor heterogeneity, nonspecific binding of polyclonal antibodies, and normal low-rate false negative/positive detection using QuPath.

Post-surgical normal HPA activity was likely due to the de-suppression of the HPA axis by medical therapy, but it may also be explained by chronic stimulation of corticotroph cells induced by ectopic CRH secretion.

The standard approach to managing EAS involves surgical intervention. However, surgery may not be a viable option in cases where the source of ACTH production is unknown. Medical therapy to reduce or block excess cortisol can be used in such circumstances.

Conclusions

In conclusion, a pheochromocytoma causing EAS should be considered even in the absence of elevated plasma metanephrines. These tumors may simultaneously express ACTH and CRH.CRH.

References

Cited by (0)

Sources of support: None

Permission in the form of written consent from patient for use of actual test results was obtained.

Cushing in silent pheochromocytoma

Clinical Relevance

This case highlights the importance of considering ectopic ACTH secretion by a pheochromocytoma in patients presenting with rapid progression and considerable clinical hypercortisolism concomitant with an adrenal mass and elevated plasma ACTH. This represents an unusual manifestation of a specific subtype of ACTH/CRH-secreting pheochromocytoma that did not exhibit catecholamine secretion

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper

∗

These 2 authors contributed equally to this work

From https://www.sciencedirect.com/science/article/pii/S2376060524000075

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Paediatric Cushing Syndrome: Prospective, Multisite, Observational Cohort Study

Posted on January 19, 2024 by MaryO

Summary

Background

Paediatric endogenous Cushing syndrome is a rare condition with variable signs and symptoms of presentation. We studied a large cohort of paediatric patients with endogenous Cushing syndrome with the aim of describing anthropometric, clinical, and biochemical characteristics as well as associated complications and outcomes to aid diagnosis, treatment, and management.

Methods

In this prospective, multisite cohort study, we studied children and adolescents (≤18 years at time of presentation) with a diagnosis of Cushing syndrome. Patients had either received their initial diagnosis and evaluation at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Bethesda, MD, USA) or been referred from other centres in the USA or outside the USA. We collected participants’ clinical, biochemical, and imaging findings and recorded their post-operative course until their latest appointment.

Findings

Of 342 paediatric patients with a diagnosis of Cushing syndrome, 193 (56%) were female and 149 (44%) male. 261 (76%) patients had corticotroph pituitary neuroendocrine tumours (Cushing disease), 74 (22%) had adrenal-associated Cushing syndrome, and seven (2%) had ectopic Cushing syndrome. Patients were diagnosed at a median of 2 years (IQR 1·0–3·0) after the first concerning sign or symptom, and patients with adrenal-associated Cushing syndrome were the youngest at diagnosis (median 10·4 years [IQR 7·4–13·6] vs 13·0 years [10·5–15·3] for Cushing disease vs 13·4 years [11·0–13·7] for ectopic Cushing syndrome; p<0·0001). Body-mass index z-scores did not differ between the diagnostic groups (1·90 [1·19–2·34] for adrenal-associated Cushing syndrome vs 2·18 [1·60–2·56] for Cushing disease vs 2·22 [1·42–2·35] for ectopic Cushing syndrome; p=0·26). Baseline biochemical screening for cortisol and adrenocorticotropin at diagnosis showed overlapping results between subtypes, and especially between Cushing disease and ectopic Cushing syndrome. However, patients with ectopic Cushing syndrome had higher urinary free cortisol (fold change in median cortisol concentration from upper limit of normal: 15·5 [IQR 12·7–18·0]) than patients with adrenal-associated Cushing syndrome (1·5 [0·6–5·7]) or Cushing disease (3·9 [2·3–6·9]; p<0·0001). Common complications of endogenous Cushing syndrome were hypertension (147 [52%] of 281 patients), hyperglycaemia (78 [30%] of 260 patients), elevated alanine transaminase (145 [64%] of 227 patients), and dyslipidaemia (105 [48%] of 219 patients). Long-term recurrence was noted in at least 16 (8%) of 195 patients with Cushing disease.

Interpretation

This extensive description of a unique cohort of paediatric patients with Cushing syndrome has the potential to inform diagnostic workup, preventative actions, and follow-up of children with this rare endocrine condition.

Funding

Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development, National Institutes of Health.

Introduction

Paediatric endogenous Cushing syndrome is a rare disorder accounting for 5–7% of all reported cases of endogenous Cushing syndrome.1, 2, 3 In children older than 5–7 years and adolescents, endogenous Cushing syndrome is most commonly caused by corticotroph pituitary neuroendocrine tumours (PitNETs) and is termed Cushing disease. By contrast, Cushing syndrome in children younger than 5 years is often associated with adrenal disorders and is termed adrenal-associated Cushing syndrome.4 Albeit rare, a third type termed ectopic Cushing syndrome is caused by neuroendocrine tumours outside the hypothalamic–pituitary axis that secrete adrenocorticotropin or corticotropin-releasing hormone.5, 6 Thus endogenous Cushing syndrome is caused by either adrenocorticotropin-dependent sources (pituitary or ectopic) or adrenocorticotropin-independent (adrenal) hypercortisolemia.

Patients with adults-onset Cushing syndrome typically present with weight gain, skin manifestations (striae, hirsutism, acne, and easy bruising), and abnormal fat deposition.7, 8, 9 Paediatric Cushing syndrome differs from adult-onset Cushing syndrome in aspects including effects on growth (weight gain with concomitant height deceleration), atypical physical presentation (such as lack of centripetal obesity or typical striae), delayed or suppressed puberty, and variable mental health problems and neurocognitive function deficits.10 Diagnosis of paediatric Cushing syndrome is therefore challenging, and delayed evaluation is common.

Research in context

Evidence before this study

Endogenous Cushing syndrome is a rare endocrine condition. Diagnosis can be challenging and delay treatment. We searched PubMed for articles published in English on paediatric Cushing syndrome using terms “Cushing” AND “children” from database inception to May 5, 2023. Although several case series of paediatric Cushing disease were identified, only a few studies of the various causes of paediatric endogenous Cushing syndrome were available.

Added value of this study

To our knowledge, this cohort of paediatric endogenous Cushing syndrome of various causes is one of the largest sources of cumulative clinical, anthropometric, and biochemical data on the presentation, diagnosis, and management. We confirm that baseline biochemical data cannot aid differential diagnosis of Cushing syndrome subtypes. However, evidence suggests that minimally invasive stimulation tests could be a safe alternative to interventional sampling procedures such as inferior petrosal sinus sampling. We provide the prevalence of complications related to Cushing syndrome. Long-term outcomes of paediatric patients with pituitary corticotroph tumours recurrence is possible up to 8 years after initial remission.

Implications of all the available evidence

Data from this large paediatric cohort inform the evaluation, diagnosis, and long-term care of patients with paediatric Cushing syndrome. We recommend an algorithm for the diagnosis of patients and screening of complications. Screening for recurrence in patients with Cushing disease is indicated for this age group, at least for the first decade after surgery.

We have evaluated a large cohort of children and adolescents with endogenous Cushing syndrome of various causes. The aim of the study was to document anthropometric, clinical, and biochemical characteristics, complications, and outcomes of paediatric endogenous Cushing syndrome to aid clinicians in the diagnosis and management of these patients.

Section snippets

Study design and participants

In this prospective, multisite cohort study, we screened participants who, from 1995 to 2023, had enrolled in studies under protocols 97-CH-0076 (clinicaltrials.gov, NCT00001595), 95-CH-0059 (NCT00001452), and 00-CH-0160 (NCT00005927) at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD, Bethesda, MD, USA). Paediatric patients (18 years or younger at time of presentation) with a diagnosis of Cushing syndrome were eligible for inclusion in the study. We

Results

342 patients with paediatric Cushing syndrome were included in the study (table 1). 278 patients were referred from centres in the USA, and 64 patients were referred from centres outside of the USA. 261 (76%) patients were diagnosed with Cushing disease, 74 (22%) patients were diagnosed with adrenal-associated Cushing syndrome, and seven (2%) patients were diagnosed with ectopic Cushing syndrome. Patients with adrenal-associated Cushing syndrome were diagnosed at a younger age than patients

Discussion

We present extensive and unique data on presentation, diagnosis, and follow-up of paediatric patients with three diagnostic types of endogenous Cushing syndrome. Clinical and anthropometric characteristics were similar across subtypes of Cushing syndrome, but biochemical tests differed. We also present extensive information on complications; hypertension, insulin resistance, dyslipidaemia, and elevated ALT were common. Long-term follow-up of patients revealed excellent postoperative prognosis,

Data sharing

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Declaration of interests

CAS holds patents on the function of the PRKAR1A, PDE11A, and GPR101 genes and related issues; his laboratory had received research funding on GPR101, and on abnormal growth hormone secretion and its treatment by Pfizer. CAS receives support from ELPEN and has been consulting for Lundbeck Pharmaceuticals and Sync. CT reports receiving research funding on treatment of abnormal growth hormone secretion by Pfizer.

References (38)

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Cushing’s Syndrome Presenting as Non-Atherosclerotic Myocardial Infarction and Heart Failure

Posted on November 6, 2023 by MaryO

Abstract

Cushing’s syndrome is a rare cause of myocardial infarction and heart failure. Herein, we report a female patient who presented acute myocardial infarction and heart failure with reduced ejection fraction. The patient was found to have hypercortisolism secondary to adrenocortical adenoma and responded well to therapy. This case underlines the effects of hypercortisolism on the cardiovascular system. The clinical presentation of this patient is unique because non-atherosclerotic myocardial infarction is rarely reported in Cushing’s syndrome patients.

Introduction

Cushing’s syndrome is an endocrine condition associated with excessive secretion of cortisol. Hypertension, vascular atherosclerosis, and chronic cardiac remodelling and dysfunction are commonly recognized cardiovascular complications in Cushing’s syndrome patients.1 Herein, we report a rare case of Cushing’s syndrome patient with a primary diagnosis of non-atherosclerotic myocardial infarction and heart failure (HF).

Case Report

A 61-year-old female with a past medical history of chronic obstructive pulmonary disease was admitted with sudden onset chest pain on 6 February 2018. Electrocardiogram showed ST-segment elevation in leads V3–V5. Blood biochemical results of 1 h after the onset of chest pain: cardiac troponin I (cTnI) 0.06 ug/L↑, creatine kinase (CK) 63 U/L, creatine phosphokinase-MB (CK-MB) 22 U/L, aspartate transferase (AST) 19 U/L, and lactic dehydrogenase (LDH) 482 U/L. Myocardial injury markers were markedly elevated at the time point of 18 h after onset: cTnI 13.9 ug/L↑, CK 613 U/L↑, CK-MB 102 U/L↑, AST 112 U/L↑, and LDH 833 U/L↑. Due to the acute ECG changes and elevated myocardial injury markers, the patient was preliminarily diagnosed as ST-segment elevation myocardial infarction (STEMI) and underwent coronary angiography, which showed no stenosis, occlusion or dissection of coronary arteries (Figure 1). Echocardiography showed enlarged left atrial dimension (LAD, 55 mm) and left ventricular end diastolic dimension (LVDd, 57 mm), and reduced ejection fraction (EF, 33%). The patient was treated for STEMI and HF, and was started on aspirin, statin, diuretic of furosemide and spirolactone, metoprolol, and Sacubitril/valsartan (SV, initiated June, 2020). The patient was strictly adherent to the medication prescribed (Table 1).

Details are in the caption following the image

Coronary angiogram demonstrating no significant obstruction in coronary artery circulation.
Table 1. Echocardiography results
2020-06-22 2020-09-02 2021-03-29 2021-06-02 2021-09-01 2021-10-22 2021-12-21
LAD (mm) 55 55 46 52 47 44 41
LVDd (mm) 57 57 53 55 54 51 55
IVS (mm) 10 10 11 10 10 10 11
LVPW (mm) 11 11 11 10 11 9 10
EF (%) 33 30 31 39 47 49 52.5
  • EF, ejection fraction; IVS, interventricular septum; LAD, left atrium dimension; LVDd, left ventricular end diastolic dimension; LVPW, left ventricular posterior wall.

However, the patient’s condition was not improved despite optimized medication. On 26 January 2021, the patient was re-admitted with recurrent chest distress and oedema, with new symptoms of facial plethora, centripetal obesity, and hyperglycaemia (Figure S1). Abdominal CT scan showed a right adrenal adenoma (Figure 2). Cardiac magnetic resonance imaging revealed enlarged LVDd (62 mm), and reduced EF, with delayed myocardial enhancement and evidence of myocardial fibrosis and fatty deposits (Figure 3). Laboratory findings showed hypokalaemia: potassium 3.0 mmol/L, elevated serum cortisol level, low plasma ACTH level, and positive 1-mg overnight dexamethasone suppression test. Based on the above findings, the patient was diagnosed with Cushing’s syndrome and started treatment with the glucocorticoid receptor inhibitor mifepristone on 5 February 2021.

Details are in the caption following the image

Abdominal CT scan showed adrenal adenoma at the right.

Details are in the caption following the image

Cardiac magnetic resonance imaging revealed enlarged LVDd, reduced EF, with delayed myocardial enhancement, evidence of myocardial fibrosis and fatty deposits.

With mifepristone added to the previous medical therapy (aspirin, statin, sacubitril/valsartan, metoprolol and diuretic of furosemide and spirolactone, and mifepristone), the patient’s condition and cardiac function improved, and echocardiography (21 December 2021) showed increased EF (52.5%). The patient underwent partial adrenalectomy on 22 December 2021. Postoperative pathology confirmed adrenal cortical adenoma. At last follow-up on 29 May 2023, the patient showed marked improvement in face and body shape, with no complaints of chest distress or oedema (Figure S2).

Discussion

In this case, the patient was first evaluated for STEMI due to her symptoms of chest pain, and the elevated ST-segment on ECG, along with the moderately elevated troponin I and other cardiac enzyme levels. However, coronary atherosclerotic heart disease was ruled out by the normal cardiac catheterization. We presume that a possible reason for acute myocardial infarction (AMI) might be vasospastic angina due to abnormal hormone levels with Cushing’s syndrome, leading to increased excessive myocardial metabolic demand and relative myocardial hypoxia, which eventually induced myocardial infarction. Although coronary atherosclerotic heart disease is the main cause of AMI, many non-atherosclerotic processes can lead to an imbalance between decreased coronary blood flow and increased myocardial metabolic demand. To date, non-atherosclerotic myocardial infarction has rarely been reported in Cushing’s syndrome patients. Vieira JT et al. reported that a patient with Cushing’s disease was considered to have spontaneous coronary artery dissection, which is a rare reason for AMI.2

Cushing’s syndrome is associated with an increased risk of cardiac failure,3 with both structural alterations and functional impairment. In our case, the patient’s CMR imaging showed typical features of cardiac geometry, function, and fibrosis, in accordance with previous reports.4 The underlying mechanisms may be the enhanced responsiveness to angiotensin II and activation of the mineralocorticoid receptor in direct response to cortisol excess.5

Our patient responded well to the therapy of conventional anti-HF medication of sacubitril/valsartan, metoprolol, and diuretic, once mifepristone was added. This favourable response to the pharmacological regimen supports the benefits of the agents for the normalization of excess cortisol. This case indicates that early diagnosis and effective treatment of Cushing’s syndrome may be crucial in preventing irreversible cardiac dysfunction secondary to cardiovascular events and heart failure.

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (81900409 and 82172182) and the PLA Youth Training Project for Medical Science (19QNP037).

Conflict of interest

The authors declares that there is no conflict of interest.

From https://onlinelibrary.wiley.com/doi/10.1002/ehf2.14548

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