MEKT1 Could Be a Potential New Therapy for Treating Cushing’s Disease

MEKT1, a type of therapy called a PPAR-γ agonist, acts to reduce levels of the adrenocorticotropic hormone and could be a potential new therapy for Cushing’s disease, according to researchers.

Their study, “Inhibitory Effects of a Novel PPAR-γ Agonist MEKT1 on Pomc Expression/ACTH Secretion in AtT20 Cells,” was published in the journal PPAR Research.

Cushing’s disease is caused by a tumor in the pituitary gland — generally a type of tumor called an adenoma that produces high levels of adrenocorticotropic hormone (ACTH).

ACTH causes the adrenal glands to make too much cortisol, leading to the classic symptoms associated with Cushing’s disease.

PPAR-gamma (PPAR-γ) is a transcription factor protein (meaning it regulates the levels of certain genes by acting through other proteins), and is seen in high levels in the normal human pituitary and in ACTH-secreting pituitary adenomas.

The Pomc gene is a precursor molecule to ACTH. While it is known that PPAR-γ plays a role in regulating Pomc levels, its mechanism has not yet been clarified in pituitary cells.

PPAR-γ agonists — agents that activate PPAR-γ — include the medications rosiglitazone and pioglitazone, both of which are used to treat type 2 diabetes. Some studies have shown that rosiglitazone and pioglitazone have an effect on Pomc suppression, which would lead to lower levels of ACTH and help treat patients with Cushing’s disease.

However, the benefits of PPAR-γ agonists in the treatment of Cushing’s disease are still controversial.

Researchers examined the effects of a new PPAR-γ agonist, MEKT1, on Pomc levels and ACTH secretion using a mouse pituitary tumor-derived cell line called AtT20 cells. They also compared its effects with the well-established PPAR-γ agonists rosiglitazone and pioglitazone.

AtT20 cells were treated with either MEKT1, rosiglitazone, or pioglitazone at various concentrations ranging from 1 nM to 10 μM (micrometers) for 24 hours.

Results showed that 10 μM of MEKT1 significantly inhibited Pomc gene levels compared to rosiglitazone and pioglitazone. Additionally, ACTH secretion from AtT20 cells was also significantly inhibited by the agonist.

To see if it worked to decrease Pomc levels by acting specifically on PPAR-γ, researchers eliminated the PPAR-γ protein using a technique called siRNA knockdown. In this case, the effects of MEKT1 on Pomc levels were significantly halted.

It is known that other proteins, such as Nur77, Nurr1, and Tpit activate Pomc levels by binding to the promoter region of Pomc — the area of the gene responsible for activating gene levels.

To determine whether these proteins could be targeted by MEKT1, researchers also looked at levels of Nur77, Nurr1, and Tpit. The PPAR-γ agonist was found to significantly suppress the levels of the three genes that encode these proteins.

“Although clinical trials of MEKT1 are needed to determine its drug efficacy in the future, it can be speculated that MEKT1 is much more effective than the previously recognized PPAR-γ agonists rosiglitazone, and pioglitazone for the suppression of Pomc expression/ACTH secretion from our in vitro [laboratory] research,” they added.

Results from this study suggest MEKT1 could be a potential new therapy for the treatment of Cushing’s disease.

From https://cushingsdiseasenews.com/2018/06/12/mekt1-could-be-potential-therapy-treatment-cushings-disease/

Health Alert: Adrenal Crisis Causes Death in Some People Who Were Treated with hGH

Doctors conducting the follow-up study of individuals treated with hGH looked at causes of death among recipients and found some disturbing news. Many more people have died from a treatable condition called adrenal crisis than from CJD (MaryO’Note: Creutzfeldt-Jakob Disease). This risk does not affect every recipient. It can affect those who lack other hormones in addition to growth hormone. Please read on to find out if this risk applies to you. Death from adrenal crisis can be prevented.

Adrenal crisis is a serious condition that can cause death in people who lack the pituitary hormone ACTH. ACTH is responsible for regulating the adrenal gland. Often, people are unaware that they lack this hormone and therefore do not know about their risk of adrenal crisis.

Most people who were treated with hGH did not make enough of their own growth hormone. Some of them lacked growth hormone because they had birth defects, tumors or other diseases that cause the pituitary gland to malfunction or shut down. People with those problems frequently lack other key hormones made by the pituitary gland, such as ACTH, which directs the adrenal gland to make cortisol, a hormone necessary for life. Having too little cortisol can be fatal if not properly treated.

Treatment with hGH does not cause adrenal crisis, but because a number of people lacking growth hormone also lack ACTH, adrenal crisis has occurred in some people who were treated with hGH. In earlier updates we have talked about how adrenal crisis can be prevented, but people continue to die from adrenal crisis, which is brought on by lack of cortisol. These deaths can be prevented. Please talk to your doctor about whether you are at risk for adrenal crisis.

  • Why should people treated with hGH know about adrenal crisis? Among the people who received hGH, those who had birth defects, tumors, and other diseases affecting the brain lacked hGH and often, other hormones made by the pituitary gland. A shortage of the hormones that regulate the adrenal glands can cause many health problems. It can also lead to death from adrenal crisis. This tragedy can be prevented.
  • What are adrenal hormones? The pituitary gland makes many hormones, including growth hormone and ACTH, a hormone which signals the adrenal glands to make cortisol, a hormone needed for life. If the adrenal gland doesn’t make enough cortisol, replacement medications must be taken. The most common medicines used for cortisol replacement are:
    • Hydrocortisone
    • Prednisone
    • Dexamethasone
  • What is adrenal crisis? Adrenal hormones are needed for life. The system that pumps blood through the body cannot work during times of physical stress, such as illness or injury, if there is a severe lack of cortisol (or its replacement). People who lack cortisol must take their cortisol replacement medication on a regular basis, and when they are sick or injured, they must take extra cortisol replacement to prevent adrenal crisis. When there is not enough cortisol, adrenal crisis can occur and may rapidly lead to death.
  • What are the symptoms of lack of adrenal hormones? If you don’t have enough cortisol or its replacement, you may have some of these problems:
    • feeling weak
    • feeling tired all the time
    • feeling sick to your stomach
    • vomiting
    • no appetite
    • weight loss

    When someone with adrenal gland problems has weakness, nausea, or vomiting, that person needs immediate emergency treatment to prevent adrenal crisis and possible death.

  • Why are adrenal hormones so important? Cortisol (or its replacement) helps the body respond to stress from infection, injury, or surgery. The normal adrenal gland responds to serious illness by making up to 10 times more cortisol than it usually makes. It automatically makes as much as the body needs. If you are taking a cortisol replacement drug because your body cannot make these hormones, you must increase the cortisol replacement drugs during times of illness, injury, or surgery. Some people make enough cortisol for times when they feel well, but not enough to meet greater needs when they are ill or injured. Those people might not need cortisol replacement every day but may need to take cortisol replacement medication when their body is under stress. Adrenal crisis is extremely serious and can cause death if not treated promptly. Discuss this problem with your doctor to help decide whether you need more medication or other treatment to protect your health.
  • How is adrenal crisis treated? People with adrenal crisis need immediate treatment. Any delay can cause death. When people with adrenal crisis are vomiting or unconscious and cannot take medicine, the hormones can be given as an injection. Getting an injection of adrenal hormones can save your life if you are in adrenal crisis. If you lack the ability to make cortisol naturally, you should carry a medical ID card and wear a Medic-Alert bracelet to tell emergency workers that you lack adrenal hormones and need treatment. This precaution can save your life if you are sick or injured.
  • How can I prevent adrenal crisis?
    • If you are always tired, feel weak, and have lost weight, ask your doctor if you might have a shortage of adrenal hormones.
    • If you take hydrocortisone, prednisone, or dexamethasone, learn how to increase the dose when you become ill.
    • If you are very ill, especially if you are vomiting and cannot take pills, seek emergency medical care immediately. Make sure you have a hydrocortisone injection with you at all times, and make sure that you and those around you (in case you’re not conscious) know how and when to administer the injection.
    • Carry a medical ID card and wear a bracelet telling emergency workers that you have adrenal insufficiency and need cortisol. This way, they can treat you right away if you are injured.

Remember: Some people who lacked growth hormone may also lack cortisol, a hormone necessary for life. Lack of cortisol can cause adrenal crisis, a preventable condition that can cause death if treated improperly. Deaths from adrenal crisis can be prevented if patients and their families recognize the condition and are careful to treat it right away. Adrenal crisis is a medical emergency. Know the symptoms and how to adjust your medication when you are ill. Taking these precautions can save your life.

From https://www.niddk.nih.gov/health-information/endocrine-diseases/national-hormone-pituitary-program/health-alert-adrenal-crisis-causes-death-people-treated-hgh

Cushing’s Syndrome Eludes Treatment Paradigm or Standard Approach to Care

Results of two systematic reviews indicate that while surgery is the preferred treatment, many patients present with contraindications without an accepted management paradigm leaving clinicians to follow a patient-centric approach to care.

With commentary by Eliza B. Geer, MD

Cushing’s syndrome may arise from an endogenous glucocorticoid excess is either adrenocorticotropic hormone (ACTH)-dependent or ACTH-independent; each variation has numerous underlying causes, including pituitary tumor, adrenal tumor, or other unknown causes.

Although rare, ectopic Cushing’s syndrome results from a non-pituitary ACTH-producing source. Cushing’s disease, a type of Cushing’s syndrome, affects an estimated 1.2 to 2.4 million people each year, and is caused by an ACTH-secreting pituitary adenoma.1

While surgery is preferred for treatment of Cushing's syndrome many patients need a medical approach instead.

Gaining insights into treatment preferences and efficacy for Cushing’s syndrome were the focus of two separate systematic reviews and meta-analyses, both published in the journal, Pituitary: one regarding medical treatments for Cushing’s syndrome,2 and the other comparing endoscopic versus microscopic transsphenoidal surgery for Cushing’s disease.3

Assessing Medical Management of Cushing’s Syndrome

The meta-analysis examining medical care of individuals with Cushing’s syndrome encompassed 1520 total patients across 35 studies, most of whom had Cushing’s disease.2 However, only 2 of the 35 studies were randomized trials, highlighting the lack of and clear need for controlled clinical trials on medical therapies for Cushing’s syndrome.

Surgery is typically first-line treatment—whether transsphenoidal pituitary adenomectomy for Cushing’s disease,4 removal of the ACTH-producing tumor in ectopic Cushing’s syndrome or adrenalectomy in ACTH-independent Cushing’s syndrome.5

However, many patients require medical therapy owing to contraindications for surgery, for recurrent disease, or to control cortisol secretion prior to surgery or radiotherapy. Results of the meta-analysis reflected wide-ranging normalization of cortisol levels depending upon the agent used– from 35.7% for cabergoline to nearly 82% for mitotane in Cushing’s disease.2 Combination therapy (medications used either together or sequentially) was shown to increase effectiveness in normalizing cortisol levels.2

In an interview with EndocrineWeb, Eliza B. Geer, MD, medical director of the Multidisciplinary Pituitary and Skull Base Tumor Center at Memorial Sloan Kettering Cancer Center in New York City, noted that most medical therapies for Cushing’s syndrome are used off-label (in the US), and thus may lack clinical trial efficacy and safety data; consequently, this review provides useful information for treatment selection. However, Dr. Geer said there was substantial diversity of treatments reviewed in this paper – including tumor-directed therapies, cortisol synthesis inhibitors, an adrenolytic therapy, and a receptor blocker, used alone or in combination.

Further, treatments used in the studies addressed a range of Cushing’s etiologies and reflected heterogeneous study designs (for example follow-up ranged from 2 weeks to 11.5 years).2  As such, she said, “findings provided by this review should be viewed in the context of a broader clinical understanding of Cushing’s treatment.”

Specifically, Dr. Geer said, “Dr. Broersen’s analysis found that efficacy of medical therapy was improved by prior radiotherapy. But we know that radiotherapy is recommended on an individualized basis in only a fraction of Cushing’s patients, depending on tumor behavior and treatment history. Also, the fact that mitotane was shown here to have the highest efficacy of all therapies does not make this the appropriate treatment for all, or even most, Cushing’s patients; mitotane is adrenolytic and has a high rate of significant adverse effects.”

Too Many Questions Persist, Necessitating Focus on Attaining Management Paradigm

Dr. Geer also highlighted the need for answers to basic questions when investigating Cushing’s treatments: How do we define ‘successful’ treatment? What goals of care can patients expect? Which cortisol measurements and cut-offs can be used? How do we define clinical remission—resolution of which symptoms and comorbidities? She said Cushing’s syndrome is one of the most challenging endocrine diseases to treat because of the lack of an accepted, universal treatment or management paradigm.

Treatment is often multimodal and always multidisciplinary, with patient-specific decision trees that must consider many factors, including goals of care, treatment history, disease etiology and severity, tumor behavior, and individual responses to medical therapies, she told EndocrineWeb.

She concluded, “While Broersen et al’s study provides a useful review of available medical therapies, it reinforces something we already know about the treatment of Cushing’s: Expertise is required.”

Pituitary surgery is first-line treatment for Cushing’s disease. Currently, there are two main techniques for transsphenoidal pituitary surgery: microscopic and endoscopic. The operating microscope provides three-dimensional vision and may be advantageous in identifying small tumors; the broader field of vision afforded by the endoscope may be advantageous for complete resection of large tumors.3  Generally, despite an absence of studies directly comparing relative remission and complication rates between microscopic versus endoscopic approaches, most surgical centers choose to use one or the other; few have both.3

Examining the Surgical Options to Manage Cushing’s Disease

The second systematic review is the first to compare remission and recurrence rates, and mortality after microscopic versus endoscopic transsphenoidal pituitary surgery for Cushing’s disease.3 The review included 97 studies of 6695 patients: 5711 individuals having the microscopic procedure and 984 undergoing endoscopic surgery.

Results of the meta-analysis found no clear difference between the two techniques in overall remission (80%) or recurrence (10%).3 Short-term mortality for both techniques was < 0.5%. However, endoscopic surgery was associated with a greater occurrence of cerebrospinal fluid leak (12.9 vs 4.0%) but a lesser occurrence of transient diabetes insipidus (11.3 vs 21.7%).3

The authors reported a higher percentage of patients in remission (76.3 vs. 59.9%) and lower percentage recurrence rates (1.5 vs 17.0%) among patients undergoing endoscopic surgery for macroadenomas.3

When interviewed regarding the second meta-analysis,3 Dr. Geer said that the potential benefit of endoscopy over microscopy has been questioned for ACTH-secreting tumors specifically since most are microadenomas.

“With the caveat that few studies (four of the 97 reviewed) compared techniques directly, Broersen et al3 found that endoscopic surgery was associated with higher remission rates compared to microscopic surgery for large tumors, but the two techniques were comparable for small tumors,” said Dr. Geer, however, “one limitation of these data is the lack of standardized criteria to define diagnosis and remission of Cushing’s among the studies reviewed.”

Need for Consistency in Clinical Trials and Surgical Expertise

The study investigators concluded, “endoscopic surgery for patients with Cushing’s disease reaches comparable results for microadenomas, and probably better results for macroadenomas than microscopic surgery,” despite the greater learning curve associated with endoscopic surgery.3 As such, based on their findings, the authors concluded that “endoscopic surgery may thus be considered the current standard of care. Microscopic surgery can be used based on neurosurgeon’s preference.” They did not respond to EndocrineWeb for a request for comment.

As more neurosurgeons receiving training with the endoscope, the preferred technique for pituitary surgery is changing. Dr. Geer said, “Broersen’s review provides reassurance that the newer endoscopic technique is at least equal to the microscope for microadenomas and may be preferred for macroadenomas.”

“However, [conclusions based on the systematic review] do not change our role as endocrinologists treating Cushing’s disease, which is to refer, when indicated, to the available neurosurgeon with the most favorable outcomes and lowest rate of complications, both of which depend directly on level of experience with the procedure and the instrument being used, whether endoscope or microscope,” she said.

The authors had no financial conflicts to declare.

From https://www.endocrineweb.com/professional/cushings/cushings-syndrome-eludes-treatment-paradigm-standard-approach-care

Tumors in Cushing’s Patients Have Distinct Genetic Profiles

A study examining the genes expressed in pituitary tumors of Cushing’s disease patients found that these tumors may be grouped into three distinct subsets.

The finding suggests that different biological processes contribute to the development of each subset, an insight that may aid in developing targeted therapies.

The study, “Gene expression profiling in human corticotrope tumors reveals distinct, neuroendocrine profiles,” was published in the Journal of Neuroendocrinology.

In Cushing disease, a pituitary tumor producing excess amounts of the adenocorticotropic hormone causes the body to produce too much cortisol.

Pituitary tumors respond differently to modulators of ACTH secretion, and patients have different disease manifestations, but what makes them differ from one another is unknown.

To determine if the genetic profile of tumors could explain the clinical diversity reported in these patients, Italian researchers evaluated 40 benign, ACTH-secreting pituitary tumors removed from patients with Cushing’s disease.

Of the 20,815 genes examined in the study, 1,259 were significantly elevated in the pituitary tumors. These were mostly involved in pathways that kept the neuroendocrine cell profile.

Based on their genetic profile, researchers were able to cluster tumors into three distinct subgroups. Samples in group A had four specific genes, associated with tumor-related processes, that were overly active. In group B, there were 313 overly active genes, involved in many of the mechanisms of hormone-secreting adenomas.

Group C had 29 highly active genes, all involved in calcium influx and cell growth – mechanisms that are important for the development of ACTH-secreting adenomas.

“It appears that these tumors present a neuroendocrine cell profile but, at the same time, clearly distinct gene expression patterns [are seen] in individual subgroups,” the researchers wrote.

Looking at clinical characteristics that correlated with each subgroup, the researchers found that most group A patients  had macroadenomas (large tumors) that had invaded the sella – the compartment where the pituitary gland resides at the base of the brain. These patients were also older than those in the other two subgroups.

Some patients in group B also had macroadenomas, but no such tumors were seen in group C. However, researchers found no association between the groups and the hormonal values, clinical findings, or surgical outcomes.

Collectively, the findings add new clues to the molecular mechanisms involved in the progression of benign pituitary tumors. They also provide new ground for developing targeted therapies, the researchers said.

From https://cushingsdiseasenews.com/2018/06/22/tumors-in-cushing-disease-patients-show-distinct-genetic-profiles-study-reports/

Cushing’s Patients at Risk of Life-threatening Pulmonary Fungal Infection

Cushing’s disease patients who exhibit nodules or masses in their lungs should be thoroughly investigated to exclude fungal infection with Cryptococcus neoformans, a study from China suggests.

While rare, the infection can be life-threatening, showing a particularly worse prognosis in patients with fluid infiltration in their lungs or with low white blood cell counts in their blood.

The study, “Cushing’s disease with pulmonary Cryptococcus neoformans infection in a single center in Beijing, China: A retrospective study and literature review,” was published in the Journal of the Formosan Medical Association.

Cortisol, a hormone that is produced in excess in Cushing’s disease patients, is a kind of glucocorticoid that suppresses inflammation and immunity. Consequently, subjects exposed to cortisol for long periods, much like immuno-compromised patients, are at high risk for infections.

In Cushing’s patients, the most common infections include Pneumocystis jiroveciAspergillus fumigatus, and Cryptococcosis — 95 percent of which are caused by C. neoformans.

But while “Cushing’s disease patients are susceptible to C. neoformans, the association between pulmonary C.neoformans and [Cushing’s disease] is poorly explored,” researchers said.

In an attempt to understand the clinical characteristics of Cushing’s patients who develop C.neoformans infections, researchers in Beijing, China, reviewed the clinical records of six patients at their clinical center.

Their analysis also included six other patients whose cases had been reported in previous publications.

Patients had a mean age of 44 and 10 were diagnosed initially with high blood pressure. Seven also had diabetes mellitus.

All patients had elevated cortisol levels in their urine and high levels of the adrenocorticotropic hormone (ACTH). Ultimately, all patients were found to have masses in their pituitary glands, causing the high cortisol and ACTH levels.

Patients complained of lung symptoms, including shortness of breath after physical activity, cough, and expectoration. But they had no fever or signs of blood in the lungs, which could suggest lung infection.

A CT scan of the chest then revealed lung nodules in four patients, and lung masses in five patients. Four patients, including one with a lung mass, also had lung air spaces filled with some material (pulmonary consolidation), which was consistent with pulmonary infection.

After analyzing lung nodule/mass biopsies, lung fluids, or blood samples, all patients were diagnosed with C. neoformans pulmonary cryptococcosis.

For their infection, patients received anti-fungal drugs, including amphotericin-B, fluconazole, flucytosine, and liposomal amphotericin. Cushing’s disease, however, was treated with surgery in 10 patients and ketoconazole in two patients.

Despite the treatments, five patients died during follow-up, including four who experienced co-infections or spreading of the cryptococcal infection and one patient with extensive bleeding after surgical removal of the gallbladder.

Among them, two patients had significantly low white blood cell levels and elevated cortisol levels, and four had infiltration in their lungs, suggesting these are markers of poor prognoses.

Researchers also noted that the patients who received ketoconazole died during in the reviewed studies. They attribute this to ketoconazole’s anti-fungal properties, which may interfere with its ability to manage Cushing’s symptoms.

Given the high susceptibility of Cushing’s disease patients to C. neoformans infections, “pulmonary nodules or masses should be aggressively investigated to exclude” this potentially fatal opportunistic infection, the researchers suggested.

“The infiltration lesions in chest CT scan and lymphopenia seem to be potential to reflect the poor prognosis,” they said.

From https://cushingsdiseasenews.com/2018/06/15/pulmonary-fungal-infection-threatens-cushings-disease-patients-study/

%d bloggers like this: