Rosario Pivonello

Prolactin and Autoimmunity

The interrelationship between prolactin (PRL) and the immune system have been elucitaded in the last decade, opening new important horizons in the field of the immunoendocrinology. PRL is secreted not only by anterior pituitary gland but also by many extrapituitary sites including the immune cells. The endocrine/paracrine PRL has been shown to stimulate the immune cells by binding to PRL receptors. Increased PRL levels, frequently described in autoimmune diseases, could depend on the enhancement of coordinated bi-directional communications between PRL and the immune system observed in these diseases. Hyperprolactinemia has been described in the active phase of some non organ-specific autoimmune diseases, as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and organ-specific autoimmune diseases, as celiac disease, type 1 diabetes mellitus, Addisons disease, autoimmune thyroid diseases. In these diseases PRL increases the syntesis of IFNγ and IL-2 by Th1 lymphocytes. Moreover, PRL activates Th2 lymphocytes with autoantibody production. Of particular interest is the association between hyperprolactinemia and levels of anti DNA antibodies, islet cell antibodies (ICA), thyreoglobulin antibodies (TgAb), thyroperoxidase antibodies (TPOAb), adrenocortical antibodies (ACA), transglutaminase antibodies (tTGAb) in SLE, in type 1 diabetes mellitus, in Hashimotos thyroiditis, in Addisons disease and in celiac disease, respectively. High levels of PRL have been also frequently detected in patients with lymphocytic hypophysitis (LYH). Several mechanisms have been invoked to explain the hyperprolactinemia in LYH. The PRL increase could be secondary to the inflammatory process of the pituitary gland but, on the other hand, this increase could have a role in enhancing the activity of the immune process in LYH. Moreover, the detection of antipituitary antibodies targeting PRL-secreting cells in some patients with idiopathic hyperprolactinemia suggests the occurrence of a possible silent LYH in these patients. Finally, the role of anti-prolactinemic drugs to inactivate the immune process in LYH is still discussed.

Increased prevalence of tricuspid regurgitation in patients with prolactinomas chronically treated with cabergoline.

BACKGROUND Cabergoline, a dopamine receptor-2 agonist used to treat prolactinomas, was associated with increased risk of cardiac valve disease in Parkinsons disease. OBJECTIVE Our objective was to evaluate prevalence of cardiac valve regurgitation in cabergoline-treated patients with prolactinomas. DESIGN AND SETTING An observational, case-control study was conducted at a university hospital. PATIENTS Fifty treated patients (44 women and six men) and 50 sex- and age-matched control subjects participated; 20 de novo patients were also studied. INTERVENTION In the treated patients, the last cabergoline dose was 1.3 +/- 1.3 mg/wk (<1 mg/wk in 44%, 1-3 mg/wk in 46%, and >3 mg/wk in 10%). Treatment duration was 12-60 months in 32% and more than 60 months in 68%. The cumulative (milligrams x months of treatment) dose of cabergoline ranged from 32-1938 mg (median 280 mg). MEASUREMENTS Valve regurgitation was assessed according to the recommendations of the American Society of Echocardiography. RESULTS In de novo patients, treated patients, and controls, the prevalence of mild regurgitation of mitral (35, 22, and 12%, P = 0.085), aortic (0, 4, and 2%, P = 0.59), tricuspid (55, 30, and 42%, P = 0.13) or pulmonic (20, 12, and 6%, P = 0.22) valves was similar. Conversely, the prevalence of moderate tricuspid regurgitation was higher in the treated patients (54%) than in de novo patients (0%) and controls (18%, P < 0.0001). Moderate tricuspid regurgitation was more frequent in patients receiving a cumulative dose above the median (72%) than in those receiving a lower dose (36%, P = 0.023). A higher systolic (P = 0.03) and diastolic blood pressure (P < 0.0001) was found in patients with than in those without moderate tricuspid regurgitation. CONCLUSION Moderate tricuspid regurgitation is more frequent in patients taking cabergoline (at higher cumulative doses) than in de novo patients and control subjects, but the clinical significance of this finding has not been established. A complete echocardiographic assessment is indicated in patients treated long term with cabergoline, particularly in those requiring elevated doses.

Cushing's Syndrome

Cushings syndrome is a rare endocrine disease characterized by cortisol hypersecretion, induced mainly by a pituitary tumor (Cushings disease) or, rarely, by an adrenal or an ectopic neuroendocine tumor. Cushings syndrome is associated with severe morbidities and an increased mortality. The major systemic complications and the main cause of death are represented by cardiovascular disease. The prognosis of the disease is mainly affected by the difficulties in the diagnosis and treatment of the disease, which remain a considerable challenge.

Dopamine receptor agonists for treating prolactinomas

Prolactinomas are the most common hormone-secreting pituitary tumours and cause infertility and gonadal and sexual dysfunction in both sexes. The approach to prolactinomas has changed in the last 25 years thanks to the availability of dopaminergic drugs characterised by a potent prolactin-inhibitory effect, a tumour shrinking effect associated with a satisfactory tolerability. In more recent years, cabergoline (1-[(6-allelylergolin-8β-yl)carbonyl]-1-[3-(dimethylamino) propyl]-3-ethyl-urea), an ergoline derivative with potent, selective and long-lasting inhibitory activity on prolactin release, has been used to suppress prolactin secretion in women with hyperprolactinaemia. Cabergoline was shown to be significantly more effective than bromocriptine in inducing a complete biochemical response and clinical efficacy and was better tolerated than bromocriptine in the majority of patients. Notable tumour shrinkage until tumour disappearance was observed during cabergoline treatment in most patients with macroprolactinoma and it was also proven effective in patients resistant to or with a poor response to bromocriptine. In view of the limited data on cabergoline-associated pregnancies and the long half-life of the drug, it is currently recommended that women hoping to become pregnant, once ovulatory cycles have been established, should discontinue cabergoline therapy 1 month before they intend to conceive. However, no data concerning negative effects on pregnancy or offspring have been reported. The great efficacy of this compound together with its excellent tolerability makes this drug the current treatment of choice for the majority of patients with hyperprolactinaemic disorders.

Increased arterial intima‐media thickness by B‐M mode echodoppler ultrasonography in acromegaly

BACKGROUND Patients with acromegaly have an increased morbidity and mortality for cardiovascular diseases. Despite the increasing evidence for the existence of a specific cardiomyopathy in acromegaly, the presence of vascular abnormalities has been never investigated.

LCI699, a potent 11β-hydroxylase inhibitor, normalizes urinary cortisol in patients with Cushing's disease: results from a multicenter, proof-of-concept study.

INTRODUCTION The clinical features and increased mortality associated with Cushings syndrome result from a chronic excess of circulating cortisol. As LCI699 potently inhibits 11β-hydroxylase, which catalyzes the final step of cortisol synthesis, it is a potential new treatment for Cushings disease, the most common cause of endogenous Cushings syndrome. METHODS Adult patients with moderate-to-severe Cushings disease (urinary free cortisol [UFC] levels >1.5 × ULN [upper limit of normal]) received oral LCI699 for 10 weeks in this proof-of-concept study. LCI699 was initiated at 4 mg/d in two equal doses; the dose was escalated every 14 days to 10, 20, 40, and 100 mg/d until UFC normalized, whereupon the dose was maintained until treatment ended (day 70). The primary endpoint was UFC ≤ ULN or a ≥50% decrease from baseline at day 70. RESULTS Twelve patients were enrolled and completed the study. Baseline UFC ranged over 1.6-17.0 × ULN. All 12 patients achieved UFC ≤ULN or a ≥50% decrease from baseline at day 70; 11 (92%) had normal UFC levels at that time. After treatment discontinuation (day 84), UFC was >ULN in 10 patients with available measurements. Mean 11-deoxycortisol, 11-deoxycorticosterone, and adrenocorticotropic hormone levels increased during treatment and declined after discontinuation. Mean systolic and diastolic blood pressure decreased from baseline by 10.0 and 6.0 mmHg, respectively. LCI699 was generally well tolerated; most adverse events (AEs) were mild or moderate. The most common AEs included fatigue (7/12), nausea (5/12), and headache (3/12). No serious drug-related AEs were reported. CONCLUSIONS LCI699 was efficacious and well tolerated in patients with Cushings disease enrolled in this proof-of-concept study.

Medical therapy for clinically non-functioning pituitary adenomas

Surgery is the first-line treatment of patients with clinically non-functioning pituitary adenomas (NFAs). Because of lack of clinical syndrome these tumours are diagnosed with a variable delay, when patients suffer from compression symptoms (hypopituitarism, headache and visual field defects) due to the extension of the tumour outside the pituitary fossa. Surgery is followed by residual tumour tissue in most patients. In these cases, radiotherapy is generally used to prevent tumour regrowth. However, NFA cell membranes, in analogy with GH- and PRL-secreting adenomas, express somatostatin and dopamine receptors. Treatment with somatostatin analogues (SSA) and dopamine agonists (DA) induced some beneficial effects on visual field defects and was also followed by tumour shrinkage in a minority of cases. DA seem to be more effective on tumour shrinkage than SSA. More recently, a combination treatment with both SSA and DA have been tested in a few patients with interesting results. Lack of randomized, placebo-controlled trials prevents any conclusion on the efficacy of these drugs. By contrast, use of gonatotrophin-releasing hormone analogues has been abandoned.

Reversal of acromegalic cardiomyopathy in young but not in middle‐aged patients after 12 months of treatment with the depot long‐acting somatostatin analogue octreotide

background Cardiovascular disease is the most frequent cause of death of patients with acromegaly.

The Treatment of Cushing's Disease

Cushings disease (CD), or pituitary-dependent Cushings syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushings syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Pathophysiology of Diabetes Mellitus in Cushing's Syndrome

Cushing’s syndrome is commonly complicated with an impairment of glucose metabolism, which is often clinically manifested as diabetes mellitus. The development of diabetes mellitus in Cushing’s syndrome is both a direct and indirect consequence of glucocorticoid excess. Indeed, glucocorticoid excess induces a stimulation of gluconeogenesis in the liver as well as an inhibition of insulin sensitivity both in the liver and in the skeletal muscles, which represent the most important sites responsible for glucose metabolism. In particular, glucocorticoid excess stimulates the expression of several key enzymes involved in the process of gluconeogenesis, with a consequent increase of glucose production, and induces an impairment of insulin sensitivity either directly by interfering with the insulin receptor signaling pathway or indirectly, through the stimulation of lipolysis and proteolysis and the consequent increase of fatty acids and amino acids, which contribute to the development of insulin resistance. Moreover, the peculiar distribution of adipose tissue throughout the body, with the predominance of visceral adipose tissue, significantly contributes to the worsening of insulin resistance and the development of a metabolic syndrome, which participates in the occurrence and maintenance of the impairment of glucose tolerance. Finally, glucocorticoid excess is able to impair insulin secretion as well as act at the level of the pancreatic beta cells, where it inhibits different steps of the insulin secretion process. This phenomenon is probably responsible for the passage from an impairment of glucose tolerance to an overt diabetes mellitus in susceptible patients with Cushing’s syndrome.