Chiara Simeoli

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.

Cardiovascular Disease in Cushing’s Syndrome: Heart versus Vasculature

Cushing’s syndrome (CS) causes metabolic abnormalities that determine an increased cardiovascular risk not only during the active phase of the disease but also for a long time after cure. Cardiovascular complications, such as premature atherosclerosis, coronary artery disease, heart failure, and stroke, in patients with CS cause a mortality rate higher than that observed in a normal population. The increased cardiovascular risk is mainly due to metabolic complications, such as metabolic syndrome, but also to vascular and cardiac alterations such as atherosclerosis and cardiac structural and functional changes. In the clinical management of patients with CS the focus should be on identifying the global cardiovascular risk and the aim should be to control not only hypertension but also other correlated risk factors, such as obesity, glucose intolerance, insulin resistance, dyslipidemia, endothelial dysfunction and the prothrombotic state. Considering that remission from hypercortisolism is often difficult to achieve and that the cardiovascular risk can persist even during disease remission, care and control of all cardiovascular risk factors should be one of the primary goals during the follow-up of these patients.

Safety of long-term treatment with cabergoline on cardiac valve disease in patients with prolactinomas

OBJECTIVE Cabergoline (CAB) has been found to be associated with increased risk of cardiac valve regurgitation in Parkinsons disease, whereas several retrospective analyses failed to detect a similar relation in hyperprolactinemic patients. The current study aimed at investigating cardiac valve disease before and after 24 and 60 months of continuous treatment with CAB only in patients with hyperprolactinemia. SUBJECTS AND METHODS Forty patients (11 men and 29 women, aged 38.7 ± 12.5 years) newly diagnosed with hyperprolactinemia entered the study. Cumulative CAB dose ranged from 12 to 588 mg (median 48 mg) at 24 months and 48-1260 mg (median 149 mg) at 60 months. All patients underwent a complete trans-thoracic echocardiographic examination. Valve regurgitation was assessed according to the American Society of Echocardiography. RESULTS At baseline, the prevalence of trace mitral, aortic, pulmonic, and tricuspid regurgitations was 20, 2.5, 10, and 40% respectively, with no patient showing clinically relevant valvulopathy. After 24 months, no change in the prevalence of trace mitral (P=0.78) and pulmonic (P=0.89) regurgitations and of mild aortic (P=0.89) and tricuspid (P=0.89) regurgitations was found when compared with baseline. After 60 months, the prevalence of trace tricuspid regurgitation was only slightly increased when compared with that after 24 months (37.5%; P=0.82), but none of the patients developed significant valvulopathy. No correlation was found between cumulative dose and prevalence or grade of valve regurgitation at both evaluations. Prolactin levels normalized in all patients but one. CONCLUSION CAB does not increase the risk of significant cardiac valve regurgitation in prolactinomas after the first 5 years of treatment.

Is diabetes in Cushing's syndrome only a consequence of hypercortisolism?

OBJECTIVE Diabetes mellitus (DM) is one of the most frequent complications of Cushings syndrome (CS). The aim of this study was to define the changes in insulin sensitivity and/or secretion in relation to glucose tolerance categories in newly diagnosed CS patients. DESIGN Cross-sectional study on 140 patients with CS. METHODS A total of 113 women (80 with pituitary disease and 33 with adrenal disease, aged 41.7±15.7 years) and 27 men (19 with pituitary disease and eight with adrenal disease, aged 38.1±20.01 years) at diagnosis were divided according to glucose tolerance into normal glucose tolerance (CS/NGT), impaired fasting glucose and/or impaired glucose tolerance (CS/prediabetes), and diabetes (CS/DM) groups. RESULTS Seventy-one patients had CS/NGT (49.3%), 26 (18.5%) had CS/prediabetes and 43 (30.8%) had CS/DM. Significant increasing trends in the prevalence of family history of diabetes (P<0.001), metabolic syndrome (P<0.001), age (P<0.001) and waist circumference (P=0.043) and decreasing trends in HOMA-β (P<0.001) and oral disposition index (DIo) (P<0.002) were observed among the groups. No significant trends in fasting insulin levels, area under the curve for insulin (AUCINS), Matsuda index of insulin sensitivity (ISI-Matsuda) and visceral adiposity index were detected. CONCLUSIONS Impairment of glucose tolerance is characterized by the inability of β-cells to adequately compensate for insulin resistance through increased insulin secretion. Age, genetic predisposition and lifestyle, in combination with the duration and degree of hypercortisolism, strongly contribute to the impairment of glucose tolerance in patients with a natural history of CS. A careful phenotypic evaluation of glucose tolerance defects in patients with CS proves useful for the identification of those at a high risk of metabolic complications.

Neuropsychiatric disorders in Cushing's syndrome

Endogenous Cushings syndrome (CS), a rare endocrine disorder characterized by cortisol hypersecretion, is associated with psychiatric and neurocognitive disorders. Major depression, mania, anxiety, and neurocognitive impairment are the most important clinical abnormalities. Moreover, patients most often complain of impairment in quality of life, interference with family life, social, and work performance. Surprisingly, after hypercortisolism resolution, despite the improvement of the overall prevalence of psychiatric and neurocognitive disorders, the brain volume loss at least partially persists and it should be noted that some patients may still display depression, anxiety, panic disorders, and neurocognitive impairment. This brief review aimed at describing the prevalence of psychiatric and neurocognitive disorders and their characterization both during the active and remission phases of CS. The last section of this review is dedicated to quality of life, impaired during active CS and only partially resolved after resolution of hypercortisolism.

Effect of Cabergoline on Metabolism in Prolactinomas

Introduction: Hyperprolactinemia has been implicated in the pathogenesis of obesity and glucose intolerance and is reportedly associated with an impaired metabolic profile. The current study aimed at investigating the effects of 12- and 60-month treatment with cabergoline (CAB) on metabolic syndrome (MetS) in patients with prolactinomas. Patients and Methods: 61 patients with prolactinomas (13 men, 48 women, 41 with microadenoma, 20 with macroadenoma), aged 34.4 ± 10.3 years, entered the study. In all patients, prolactin (PRL) and metabolic parameters were assessed at diagnosis and after 12 and 60 months of continuous CAB treatment. MetS was diagnosed according to NCEP-ATP III criteria. Results: Compared to baseline, CAB induced a significant decrease in PRL with complete normalization in 93% of patients after the 60-month treatment. At baseline, MetS prevalence was significantly higher in patients with PRL above (34.5%) than in those with PRL lower (12.5%) than the median (129 μg/l, p = 0.03). MetS prevalence significantly decreased after 12 (11.5%, p = 0.039) and 60 (5.0%, p = 0.001) months compared to baseline (28.0%). At both evaluations the lipid profile significantly improved compared to baseline. Fasting insulin and homeostatic model assessment of insulin resistance significantly decreased after 1 year of CAB (p = 0.012 and p = 0.002, respectively) and further improved after 60 months (p = 0.000). The visceral adiposity index significantly decreased after the 60-month treatment (p = 0.000) compared to baseline. At the 5-year evaluation CAB dose was the best predictor of percent decrease in fasting insulin (t = 2.35, p = 0.022). Conclusions: CAB significantly reduces MetS prevalence and improves the adipose tissue dysfunction index. The improvement in PRL, insulin sensitivity and other metabolic parameters might reflect the direct effect of CAB.

Effect of once-daily, modified-release hydrocortisone versus standard glucocorticoid therapy on metabolism and innate immunity in patients with adrenal insufficiency (DREAM): a single-blind, randomised controlled trial

BACKGROUND Conventional treatment of patients with adrenal insufficiency involves administration of glucocorticoids multiple times a day and has been associated with weight gain and metabolic impairment. The optimal glucocorticoid replacement therapy for these patients is highly debated because of the scarcity of evidence from randomised trials. We aimed to establish whether the timing and pharmacokinetics of glucocorticoid replacement therapy affect the metabolism and immune system of patients with adrenal insufficiency. METHODS We did a single-blind randomised controlled trial at two reference university hospitals in Italy. Eligible patients (aged 18-80 years) with adrenal insufficiency were on conventional glucocorticoid therapy and had been stable for at least 3 months before enrolment. Patients were randomly assigned (1:1) with a computer-generated random sequence stratified by type of adrenal insufficiency and BMI to continue conventional glucocorticoid therapy (standard treatment group) or to switch to an equivalent dose of once-daily, modified-release oral hydrocortisone (switch treatment group). Outcome assessors were masked to treatment allocation. The primary outcome was bodyweight change from baseline to 24 weeks. Secondary outcomes included immune cell profiles, susceptibility to infections, and quality of life. Efficacy analyses included all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT02277587. FINDINGS Between March 1, 2014, and June 30, 2016, 89 patients with adrenal insufficiency were randomly assigned to continue standard glucocorticoid therapy (n=43) or to switch to once-daily, modified-release hydrocortisone (n=46). At 24 weeks, bodyweight reduction was superior in patients in the once-daily hydrocortisone group compared with those in the standard treatment group (-2·1 kg [95% CI -4·0 to -0·3] vs 1·9 kg [-0·1 to 3·9]; treatment difference -4·0 kg, 95% CI -6·9 to -1·1; p=0·008). Additionally, patients in the once-daily hydrocortisone group had more normal immune cell profiles, reduced susceptibility to infections, and improved quality of life compared with the standard glucocorticoid therapy group. We observed no difference in frequency or severity of adverse events between the two intervention groups, although a lower cumulative number of recurrent upper respiratory tract infections was observed with once-daily hydrocortisone than with standard treatment (17 vs 38; p=0·016). Most adverse events were mild; three serious adverse events occurred in each group, of which one adverse advent (arthritis) in the switch treatment group could be considered drug related. INTERPRETATION Patients with adrenal insufficiency on conventional glucocorticoid replacement therapy multiple times a day exhibit a pro-inflammatory state and weakened immune defence. Restoration of a more physiological circadian glucocorticoid rhythm by switching to a once-daily, modified-release regimen reduces bodyweight, normalises the immune cell profile, reduces recurrent infections, and improves the quality of life of patients with adrenal insufficiency. FUNDING Italian Ministry of University and Research.

Cushing’s disease: the burden of illness

Cushing’s syndrome is caused by prolonged exposure to elevated cortisol levels. The most common form of endogenous Cushing’s syndrome is Cushing’s disease, which results from an adrenocorticotropic hormone-secreting pituitary tumour. Cushing’s disease is associated with increased mortality, mostly attributable to cardiovascular complications, and a host of comorbidities such as metabolic and skeletal disorders, infections and neuropsychiatric disturbances. As a consequence, Cushing’s disease substantially impairs health-related quality of life. It is crucial that the condition is diagnosed as early as possible, and that rapid and effective treatment is initiated in order to limit long-term morbidity and mortality. The initial treatment of choice for Cushing’s disease is selective transsphenoidal pituitary surgery; however, the risk of recurrence after initial surgery is high and remains so for many decades after surgery. A particular concern is the growing body of evidence indicating that the negative physical and psychosocial sequelae of chronic hypercortisolism may persist in patients with Cushing’s disease even after long-term surgical ‘cure’. Current treatment options for post-surgical patients with persistent or recurrent Cushing’s disease include second surgery, radiotherapy, bilateral adrenalectomy and medical therapy; however, each approach has its limitations and there is an unmet need for more efficacious treatments. The current review provides an overview of the burden of illness of Cushing’s disease, underscoring the need for prompt diagnosis and effective treatment, as well as highlighting the need for better therapies.

Influence of Bisphenol A on Type 2 Diabetes Mellitus

Bisphenol A (BPA) is an organic synthetic compound employed to produce plastics and epoxy resins. It is used as a structural component in polycarbonate beverage bottles and as coating for metal surface in food containers and packaging. The adverse effects of BPA on human health are widely disputed. BPA has been recently associated with a wide variety of medical disorders and, in particular, it was identified as potential endocrine-disrupting compound with diabetogenic action. Most of the clinical observational studies in humans reveal a positive link between BPA exposure, evaluated by the measurement of urinary BPA levels, and the risk of developing type 2 diabetes mellitus. Clinical studies on humans and preclinical studies on in vivo, ex vivo, and in vitro models indicate that BPA, mostly at low doses, may have a role in increasing type 2 diabetes mellitus developmental risk, directly acting on pancreatic cells, in which BPA induces the impairment of insulin and glucagon secretion, triggers inhibition of cell growth and apoptosis, and acts on muscle, hepatic, and adipose cell function, triggering an insulin-resistant state. The current review summarizes the available evidences regarding the association between BPA and type 2 diabetes mellitus, focusing on both clinical and preclinical studies.

The dual targeting of insulin and insulin-like growth factor 1 receptor enhances the mTOR inhibitor-mediated antitumor efficacy in hepatocellular carcinoma

Deregulation of mTOR and IGF pathways is frequent in hepatocellular carcinoma (HCC), thus mTOR and IGF1R represent suitable therapeutic targets in HCC. The aim of this study was to evaluate the effects of mTOR inhibitors (mTORi) and OSI-906, blocker of IGF1R/IR, on HCC cell proliferation, viability, migration and invasion, and alpha-fetoprotein (α-FP) secretion. In HepG2 and HuH-7 we evaluated, the expression of mTOR and IGF pathway components; the effects of Sirolimus, Everolimus, Temsirolimus and OSI-906 on cell proliferation; the effects of Sirolimus, OSI-906, and their combination, on cell secretion, proliferation, viability, cell cycle, apoptosis, invasion and migration. Moreover, intracellular mechanisms underlying these cell functions were evaluated in both cell lines. Our results show that HepG2 and HuH-7 present with the same mRNA expression profile with high levels of IGF2. OSI-906 inhibited cell proliferation at high concentration, while mTORi suppressed cell proliferation in a dose-time dependent manner in both cell lines. The co-treatment showed an additive inhibitory effect on cell proliferation and viability. This effect was not related to induction of apoptosis, but to G0/G1 phase block. Moreover, the co-treatment prevented the Sirolimus-induced AKT activation as escape mechanism. Both agents demonstrated to be differently effective in inhibiting α-FP secretion. Sirolimus, OSI-906, and their combination, blocked cell migration and invasion in HuH-7. These findings indicate that, co-targeting of IGF1R/IR and mTOR pathways could be a novel therapeutic approach in the management of HCC, in order to maximize antitumoral effect and to prevent the early development of resistance mechanisms.