Salk scientists find potential therapeutic target for Cushing’s disease

Posted on May 7, 2013 by MaryO

LA JOLLA, CA—Scientists at the Salk Institute for Biological Studies have identified a protein that drives the formation of pituitary tumors in Cushing’s disease, a development that may give clinicians a therapeutic target to treat this potentially life-threatening disorder.

The protein, called TR4 (testicular orphan nuclear receptor 4), is one of the human body’s 48 nuclear receptors, a class of proteins found in cells that are responsible for sensing hormones and, in response, regulating the expression of specific genes. Using a genome scan, the Salk team discovered that TR4 regulates a gene that produces adrenocorticotropic hormone (ACTH), which is overproduced by pituitary tumors in Cushing’s disease (CD). The findings were published in the May 6 early online edition of Proceedings of the National Academy of Sciences.

“We were surprised by the scan, as TR4 and ACTH were not known to be functionally linked,” says senior author Ronald M. Evans, a professor in Salk’s Gene Expression Laboratory and a lead researcher in the Institute’s Helmsley Center for Genomic Medicine. “TR4 is driving the growth and overexpression of ACTH. Targeting this pathway could therapeutically benefit treatment of CD.”

In their study, Evans and his colleagues discovered that forced overexpression of TR4 in both human and mouse cells increased production of ACTH, cellular proliferation and tumor invasion rates. All of these events were reversed when TR4 expression was reduced.

First described more than 80 years ago, Cushing’s disease is a rare disorder that is caused by pituitary tumors or excess growth of the pituitary gland located at the base of the brain. People with CD have too much ACTH, which stimulates the production and release of cortisol, a hormone that is normally produced during stressful situations.

While these pituitary tumors are almost always benign, they result in excess ACTH and cortisol secretion, which can result in various disabling symptoms, including diabetes, hypertension, osteoporosis, obesity and psychological disturbances. Surgical removal of the tumors is the first-line therapy, with remission rates of approximately 80 percent; however, the disease recurs in up to 25 percent of cases.

Drugs such as cabergoline, which is used to treat certain pituitary tumors, alone or in combination with ketoconazole, a drug normally used to treat fungal infections, have been shown to be effective in some patients with Cushing’s disease. More recently, mefipristone-best known as the abortion pill RU-486-was approved by the FDA to treat CD. Despite these advances in medical therapy, the Salk scientists say additional therapeutic approaches are needed for CD.

“Pituitary tumors are extremely difficult to control,” says Michael Downes, a senior staff scientist in the Gene Expression Laboratory and a co-author of the study. “To control them, you have to kill cells in the pituitary gland that are proliferating, which could prevent the production of a vital hormone.”

Previous studies have found that, by itself, TR4 is a natural target for other signaling molecules in the pituitary. Small-molecule inhibitors that have been developed for other cancers could be potentially applied to disrupt this signaling cascade. “Our discovery,” says Evans, a Howard Hughes Medical Institute investigator and holder of the March of Dimes Chair in Molecular and Developmental Biology, “might lead clinicians to an existing drug that could be used to treat Cushing’s disease.”

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Diagnostic performance of salivary cortisol in the diagnosis of Cushing’s syndrome, adrenal incidentaloma and adrenal insufficiency

Posted on May 1, 2013 by MaryO

Source

F Ceccato, Department of Medicine – DIMED, University of Padova, Endocrinology Unit, Padova, Italy.

Abstract

OBJECTIVE:

Salivary cortisol has been recently suggested for studies on the hypothalamic-pituitary-adrenal (HPA) axis: lack of circadian rhythm is a marker of Cushing’s syndrome (CS), and some authors report that low salivary cortisol levels may be a marker of adrenal insufficiency. The aim of our study was to define the role of salivary cortisol in specific diagnostic setting of HPA axis disease.

SUBJECTS AND METHODS:

We analyzed morning salivary cortisol (MSC) and late night salivary cortisol (LNSC) in 406 subjects: 52 Cushing’s disease (CD), 13 ectopic-CS, 17 adrenal-CS, 27 CD in remission (mean follow-up of 66 ± 39 months), 45 adrenal incidentalomas, 73 patients assessed of CS and then ruled out for endogenous hypercortisolism, 75 patients with adrenal insufficiency and 104 healthy subjects.

RESULTS:

A LNSC value above 5.24 ng/mL differentiated CS from controls with high sensitivity (96.3%) and specificity (97.1%), we found higher LNSC in ectopic-CS than in CD. We found no difference in MSC and LNSC levels between CD in remission and healthy subjects. Both MSC and LNSC were higher in adrenal incidentaloma than in healthy controls. MSC below 2.65 ng/mL distinguished patients with adrenal insufficiency from controls with high sensitivity (97.1%) and specificity (93.3%).

CONCLUSIONS:

salivary cortisol is a useful tool to assess endogenous cortisol excess or adrenal insufficiency and to evaluate stable CD in remission.

PMID:

 

23610124

 

[PubMed – as supplied by publisher]
From PubMed
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Cushing’s Syndrome, Prostate Cancer and Adrenocortical Carcinoma

Posted on March 11, 2013 by MaryO

Orphagen has identified and characterized small molecule antagonists to steroidogenic factor-1 (SF-1). SF-1 binds to and regulates DNA promoter elements in the major transporters and enzymes required for adrenal steroid synthesis. It is also required for development of the adrenal gland. SF-1 antagonists inhibit cortisol secretion in adrenal cells and have potential application in two orphan indications, Cushing’s syndrome and adrenocortical carcinoma. In addition, SF-1 appears to have an important role in the progression of advanced prostate cancer.

 

cushings-adrenocortical-crop

 

Cushing’s syndrome:
An estimated 20,000 people in the US have Cushing’s, with more than 3,000 new cases diagnosed each year. The incidence is similar in Europe. Cushing’s syndrome disproportionately affects females, who make up about 75% of the diagnosed cases. Symptoms of Cushing’s syndrome can include obesity, diabetes, psychiatric disorders, osteoporosis and immune suppression. Cushing’s syndrome is caused by elevated secretion of cortisol from the adrenal gland, in association with pituitary, adrenal or other cancers.

Orphagen has identified small molecule antagonists to SF-1 that have the potential to suppress cortisol levels in all Cushing’s patients without serious side effects.

Adrenocortical carcinoma (ACC):
ACC is a rare malignancy with an extremely poor prognosis (5-year overall survival: 37-47%). Complete surgical resection offers hope for long-term survival but surgery is not an option in up to two-thirds of patients because metastasis has usually occurred by the time of diagnosis.

SF-1 is recognized as a potential mechanism-based therapeutic target for control of ACC and an SF-1 antagonist could be used in the treatment of ACC.

Pediatric ACC:
Pediatric ACC is a very rare but aggressive cancer with a long-term survival rate of about 50%. Approximately 60% of children with adrenocortical tumors are diagnosed before the age of four. The SF-1 gene is amplified and SF-1 protein is overexpressed in the vast majority of childhood adrenocortical tumors strongly implicating SF-1 in pediatric adrenocortical tumorigenesis.

Castration resistant prostate cancer (CRPC):
CRPC is the most common cancer in males. Surgery is not an option if the cancer has spread beyond the prostate gland, at which point patients typically receive hormonal therapy, essentially chemical castration. This course of therapy usually fails within two years, resulting in castration resistant prostate cancer (CRPC). Most patients eventually succumb to CRPC, which is the second leading cause of cancer deaths in men.
SF-1 antagonists may: (1) block the adrenal androgens that circumvent chemical castration, and are a primary cause of CRPC; and (2) inhibit synthesis of androgens within the prostate tumor itself, where SF-1 may control induction of enzymes for de novo androgen synthesis in treatment-resistant cancers.

From http://www.orphagen.com/research_cushings.html

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Early Detection, Treatment Needed To Reduce Risk Of Death, Cardiovascular Disease In Cushing’s Disease Patients

Posted on February 20, 2013 by MaryO

Even after successful treatment, patients with Cushing’s disease who were older when diagnosed or had prolonged exposure to excess cortisol face a greater risk of dying or developing cardiovascular disease, according to a recent study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).

Cushing’s disease is a rare condition where the body is exposed to excess cortisol – a stress hormone produced in the adrenal gland – for long periods of time.

Researchers have long known that patients who have Cushing’s disease are at greater risk of developing and dying from cardiovascular disease than the average person. This study examined whether the risk could be eliminated or reduced when the disease is controlled. Researchers found that these risk factors remained long after patients were exposed to excess cortisol.

“The longer patients with Cushing’s disease are exposed to excess cortisol and the older they are when diagnosed, the more likely they are to experience these challenges,” said Eliza B. Geer, MD, of Mount Sinai Medical Center and lead author of the study. “The findings demonstrate just how critical it is for Cushing’s disease to be diagnosed and treated quickly. Patients also need long-term follow-up care to help them achieve good outcomes.”

The study found cured Cushing’s disease patients who had depression when they started to experience symptoms of the disease had an elevated risk of mortality and cardiovascular disease. Men were more at risk than women, a trend that may be explained by a lack of follow-up care, according to the study. In addition, patients who had both Cushing’s syndrome and diabetes were more likely to develop cardiovascular disease.

The study examined one of the largest cohorts of Cushing’s disease patients operated on by a single surgeon. The researchers retrospectively reviewed charts for 346 Cushing’s disease patients who were treated between 1980 and 2011. Researchers estimated the duration of exposure to excess cortisol by calculating how long symptoms lasted before the patient went into remission. The patients who were studied had an average exposure period of 40 months.

The findings may have implications for people who take steroid medications, Geer said. People treated with high doses of steroid medications such as prednisone, hydrocortisone or dexamethasone are exposed to high levels of cortisol and may experience similar conditions as Cushing’s disease patients.

“While steroid medications are useful for treating patients with a variety of conditions, the data suggests health care providers need to be aware that older patients or those who take steroid medications for long periods could be facing higher risk,” Geer said. “These patients should be monitored carefully while more study is done in this area.”

From http://www.medicalnewstoday.com/releases/256284.php

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Adrenal Insufficiency – Female Patient found Unconscious with Syringe Nearby

Posted on October 31, 2012 by MaryO

Crew’s misdiagnosis of drug overdose could have cost patient her life

Kimberly Doran | From the October 2012 Issue |

 

A call comes in to 9-1-1 dispatch. “Help” is all that’s spoken before the operator hears the phone hit the floor. The 9-1-1 dispatcher calls back only to get a busy signal. Police and EMS are dispatched for a well-being call.

On arrival, the front door is found to be slightly ajar. The crew knocks, but there’s no reply. They find a young woman  lying on the floor, naked, and in a pool of vomit. A syringe with an unknown substance is on the ground nearby. Suspecting a drug overdose, the EMS crew begins treating the patient for this condition. The patient is unconscious with emesis around her head and face. Her vital signs are blood pressure 60/45, heart rate of 130 bpm and respiratory rate of 10.

The patient shows no signs of waking. The crew clears the airway and administers oxygen. An IV is established, and the patient is readied for transport. As the crew leaves the scene, one of the medics turns to shut the door and sees a vial under a chair. He retrieves it and notes that the label says Solu-Cortef (a glucocorticoid). He bags it for the emergency department (ED). Following his instinct, he looks around the area for medications and finds two bottles. One is labeled dexamethosone and the other is labeled fludrocortisone. He takes his findings and rushes out the door into the awaiting ambulance. During transport, the patient continues to deteriorate.

The medic administers 0.5 mg of narcan and a 500mL bolus of normal saline with no response. He radios ahead to let the hospital know that they’re en route. Now questioning the original diagnosis of drug overdose, he reports the medications he found on the scene in hopes it will help the receiving physician determine the cause of the patient’s condition.

Arrival at the ED
On arrival to the ED, the medic hands over the loaded syringe containing 2mL of unidentified solution, as well as the empty vial of Solu-Cortef and the bottles of dexamethosone and fludrocortisones.

As the crew arrives at the hospital, the ED physician meets the crew and informs them that he’s familiar with the medications. He says they’re all used for people who have various forms of adrenal insufficiency (AI). The symptoms seen in this patient coincide with life-threatening adrenal crisis. The physician administers 100 mg of Solu-Cortef via IV and within minutes, the patient rouses. In 30 minutes, she can explain what happened in the desperate moments before her crisis.

Adrenal Insufficiency
Adrenal Insufficiency (AI) is a life-threatening in which the body is unable to produce enough cortisol to sustain life. In other words, their adrenal cortex is “asleep.” People suffering from AI take daily cortisol/glucocorticoid steroid replacement because whatever adrenal function is depleted. These patients are glucocorticoid dependent. In times of injury, dehydration, illness or surgery, they require an injection of Solu-Cortef. Solu-Cortef contains both glucocorticoid and mineralocorticoid properties, helping the body to compensate during a stress event.

The adrenal medulla (inside of the adrenal gland) secretes epinephrine and norepinephrine. The adrenal cortex (outer layer of the adrenal gland) secretes cortisol and aldosterone. Cortisol, a glucocorticoid, is often called the “stress” hormone. One of cortisol’s functions is elevating blood glucose levels in times of stress. It also functions as a mediator for several inflammatory pathways.

Absence of cortisol can result in hypotension, hypoglycemia and death. Aldosterone, a mineralocorticoid, is responsible for the regulation of sodium and water. Absence of aldosterone can result in hypotension and electrolyte imbalance. AI in the prehospital setting may be difficult to recognize in the absence of a good history, including medications, to point providers in the cause of the problem. Two life-threatening conditions associated with AI include hypotension and hypoglycemia.

If not managed, these two conditions are life threatening. Prehospital treatment should include management of the patient’s airway, vascular access and fluid resuscitation. If blood glucose levels are low, the patient should receive dextrose per local protocol. It’s important to complete a thorough physical assessment and obtain a complete patient history before treating patients with this condition. Providers may confuse patients having an adrenal crisis with drug overdose patients because of their similar symptoms. Although AI is rare, it should still be considered as a potential diagnosis.

Authors’ note: Parts of the above case are taken from a true story. However, the difference is that there was no syringe on the floor, no vial under the chair and no one found the medications. The patient was treated with charcoal and diagnosed as a drug-overdose patient. She likely would have died, but her mother charged into the ED and expressed the need for Solu-Cortef. Security was called, but luckily someone listened, researched and called the patient’s treating physician. The patient was treated and released. 

From Journal of Emergency Medical Services

 

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