Ioannis Karamouzis

Metabolic and cardiovascular outcomes in patients with Cushing’s syndrome of different aetiologies during active disease and 1 year after remission

Objective  Cushing’s syndrome is associated with several comorbidities responsible for the increased cardiovascular risk, not only during the active phase but also after disease remission.

Role of mineralocorticoid receptors on the hypothalamus-pituitary-adrenal axis in humans.

This clinical review will summarize the available data regarding the role of mineralocorticoid receptors (MRs) on the hypothalamus–pituitary–adrenal (HPA) axis control in physiological and pathological conditions and in the memory processes involved in the control and appraisal of a stress event. MRs are predominantly expressed in the limbic structures, with the hippocampus being the main localization, although MRs are also found at the hypothalamic level. It is known that hyppocampal MRs control the proactive feedback involved in the maintenance of the basal HPA activity, mainly at the nadir of the circadian rhythm. In physiological conditions, the administration of pharmacological doses of both MR antagonists and agonists is able to interact with the HPA activity, modifying the quiescent phase-nadir of the circadian rhythm, although some data in the literature do not support these observations. Also, in a physiological condition such as aging, an enhanced HPA axis activity is found in the time window, when MRs are predominantly occupied by cortisol circulating levels, possibly reflecting an MR impairment in this period of life. In pathology, major depression has been correlated to MR qualitative-quantitative alterations which could reflect differences on psychological and physiological responses, possibly predicting psychopathologies. Most of the remarks reported in this review seem to indicate, in agreement with animal data, a role played by MRs in the delicate control of the HPA axis in humans and the possible predisposition to the development of pathologies in case of their alterations.

Glucose metabolism in patients with subclinical Cushing’s syndrome

This clinical review will summarize the available data regarding the effect of either physiological or increased glucocorticoid concentrations on glucose metabolism and insulin-sensitivity, in order to clarify the role, if any, of subclinical Cushing’s syndrome (SCS), a status of altered hypothalamic–pituitary–adrenal axis secretion in the absence of the classical signs or symptoms of overt cortisol excess, in patients with adrenal incidentalomas (AI) and diabetes mellitus type 2. Focusing on patients with SCS associated to AI, while there is convincing evidence in the literature that even a mild hyper cortisolemia is associated with alterations of glucose metabolism, evidence is insufficient to conclude that the simple correction of chronic, even mild, hypercortisolism can completely revert metabolic, mainly glycemic alterations. At the same time, considering the variability of the prevalence of Cushing’s syndrome in patients with diabetes mellitus type 2 reported in the literature, no agreement does exist whether screening for CS can be useful and recommended in those patients.

BClI polymorphism of the glucocorticoid receptor gene is associated with increased obesity, impaired glucose metabolism and dyslipidaemia in patients with Addison's disease.

Although glucocorticoids are essential for health, several studies have shown that glucocorticoids replacement in Addisons disease might be involved in anthropometric and metabolic impairment, with increased cardiovascular risk, namely if conventional doses are used. As the effects of glucocorticoids are mediated by the glucocorticoid receptor, encoded by NR3C1 gene, different polymorphisms in the NR3C1 gene have been linked to altered glucocorticoid sensitivity in general population as well as in patients with obesity or metabolic syndrome.

Effect of acute and prolonged mineralocorticoid receptor blockade on spontaneous and stimulated hypothalamic–pituitary–adrenal axis in humans

CONTEXT Mineralocorticoid receptors (MRs) in the hippocampus display an important role in the control of the hypothalamic-pituitary-adrenal (HPA) axis, mediating the proactive feedback of glucocorticoids, which maintains the basal HPA activity. The systemic administration of MR antagonists enhances spontaneous and CRH-stimulated ACTH, cortisol, and DHEA secretion, while the effects of chronic treatment with MR antagonists are scanty. Our study was performed in order to clarify this point. DESIGN ACTH, cortisol, and DHEA levels were studied during the infusion of placebo, canrenoate, a MR antagonist (CAN, 200 mg i.v. bolus at 1600 h followed by 200 mg infused over 4 h), and human CRH (hCRH; 2.0 microg/kg i.v. bolus at 1800 h) before and during the last week of 28-day treatment with CAN (200 mg/day p.o.) in eight young women. RESULTS Pre-treatment sessions: CAN and hCRH administration increased ACTH, cortisol, and DHEA levels versus placebo (P<0.05). Post-treatment sessions: during placebo infusion, cortisol and DHEA were significantly amplified versus pre-treatment session (P<0.05), while ACTH levels were not modified; CAN infusion, differently from pre-treatment session, was not able to significantly increase ACTH, cortisol, and DHEA levels; ACTH, cortisol, and DHEA responses to hCRH were amplified with respect to pre-treatment session, although statistical significance was obtained for cortisol and DHEA only. CONCLUSIONS MR blockade by acute CAN administration significantly enhances the HPA activity in the afternoon, during the quiescent phase of the circadian rhythm. At the same period, prolonged treatment with CAN amplifies both spontaneous and CRH-stimulated activities of the HPA axis, while it blunts the HPA responsiveness to a further MR-mediated stimulation.

Enhanced oxidative stress and platelet activation in patients with Cushing's syndrome.

Cushing Syndrome (CS) is implicated by increased cardiovascular risk (CVR) leading to increased morbidity and mortality. Oxidative stress (OS) and platelet activation (PA) are associated with increased CVR. However, scarce data of OS in CS exist. Our objective was to determine the oxidant–antioxidant balance in CS.

Neuroendocrine effects of Citalopram, a selective serotonin re-uptake inhibitor, during lifespan in humans

Objective: Serotonergic system contributes to the regulation of hypothalamus-pituitary-adrenal axis. In humans, serotonergic agonists increase PRL, ACTH, and cortisol, while serotonin (5HT) influence on GH is controversial. Central 5HT activity and neuroendocrine function change during lifespan. Design: To clarify the neuroendocrine response to 5HT across lifespan, we assessed ACTH, cortisol, DHEA, PRL, and GH responses to citalopram (CT) in young adults (YA) (no.=12, 29.2±1.7 yr mean±SEM), middle aged (MA) (no.=12, 54.3±0.9 yr), and elderly (ES) (no.=12, 69.3±0.9 yr) males. All the subjects received placebo (saline iv over 120 min) or CT (20 mg iv over 120 min). Blood samples were taken every 15 min up to 240 min. Results: During placebo, ACTH, cortisol, GH, and PRL were similar in all groups while DHEA showed an age-dependent reduction from middle age (p<0.001). During CT, ACTH, and cortisol were higher than during placebo in YA (p<0.05) and even more in MA (p<0.01 vs placebo, p<0.05 vs YA); in ES, the increase of both ACTH and cortisol (p<0.05 vs placebo) was lower than in MA (p<0.05) and higher than in YA (p<0.05 for cortisol only). No changes were observed for DHEA, GH, and PRL in any group. Conclusions: Corticotrope response to CT is age-dependent in normal men, being amplified starting from middle age, suggesting precocious changes in the serotonergic neuroendocrine control during lifespan. CT is a useful tool to evaluate the age-dependent serotonergic function in humans.

Effects of cetrorelix, a GnRH-receptor antagonist, on gonadal axis in women with functional hypothalamic amenorrhea.

Background. Gonadotropin Releasing Hormone (GnRH) antagonists (GnRHa) suppress gonadotropin and sex-steroid secretion. In normal women, acute GnRHa administration induces inhibitory effect on pituitary-gonadal axis, followed by Luteinizing Hormone (LH) rebound. Functional hypothalamic amenorrhea (HA) is characterised by impaired gonadotropin secretion and hypogonadism secondary to blunted GnRH pulsatility. Methods. We studied the effects of a GnRHa, cetrorelix (CTX 3.0 mg), in six women with HA (age 30.7 ± 3.2 years; BMI 21.5 ± 1.7 kg/m2) and six control subjects (CS, 28.2 ± 0.6 years; 22.6 ± 0.9 kg/m2) on LH, Follicle-Stimulating Hormone (FSH) and oestradiol levels over 4 h (08.00–12.00 am) before, +24 h and +96 h after CTX; LH, FSH, and oestradiol were also evaluated at +6, +8, +12, +48, +72 h after CTX. Results. CS: CTX reduced (p < 0.05) LH, FSH, and oestradiol (nadir at +12 h, +24 h, and +24 h); LH rebounded at +96 h, FSH and oestradiol recovered at +48 h and +72 h. The 4-h evaluation showed LH and FSH reduction (p < 0.05) at +24 h, with LH rebound at +96 h. HA: CTX reduced (p < 0.05) LH, FSH, and oestradiol, (nadir at +24 h, +48 h, and +48 h, recovery at +48 h, +72 h, and +96 h). The 4-h evaluation showed gonadotropin reduction (p < 0.05) 24 h after CTX, without any rebound effect. Conclusions. One single CTX dose still modulates gonadotropin secretion in HA. Its ‘paradoxical’ stimulatory effect on gonadotropins needs to be verified after prolonged administration.

Secondary Adrenal Insufficiency: Where Is It Hidden and What Does It Look Like?

Adrenal failure secondary to hypothalamic-pituitary disease is a common although underestimated and underdiagnosed condition, with serious consequences. Corticotropin deficiency can be isolated or more frequently occur in association with other pituitary hormones deficiencies. The most frequent endogenous cause of secondary adrenal insufficiency (SAI) is a tumor of the hypothalamic-pituitary region, usually associated with panhypopituitarism secondary to tumor growth or to its treatment with surgery or irradiation. Less commonly, SAI is due to nontumoral disorders including infiltrative lesions, infective processes, vascular alterations, traumatic brain injury, empty sella or genetic disorders. Finally, long-term administration of exogenous glucocorticoids can determine secondary and/or tertiary hypoadrenalism acting at the hypothalamic level and leading to prolonged suppression of the hypothalamic-pituitary-adrenal axis. It is essential to perform validated diagnostic procedures in order to promptly diagnose hypoadrenalism so as to prevent an adrenal crisis. At the same time, diagnosis is complex as no single test has sufficient sensitivity to identify all patients with SAI. Therefore, clinical judgment and follow-up are crucial for the assessment of corticotropin deficiency. Patients with persisting suggestive symptoms and/or a clinical history of higher risk for adrenal insufficiency deserve careful subsequent reassessments.

Baseline glucose homeostasis predicts the new onset of diabetes during statin therapy: A retrospective study in real life

OBJECTIVEWe evaluated the risk of altered glucose levels and new-onset diabetes (NOD) associated with statins according to glucose levels at baseline in a population treated for dyslipidemia on primary prevention for >5 years. DESIGN. The retrospective study included 308 subjects (265 on statins and 43 controls on diet) with a follow-up of 5–15 years. The cohort was classified according to glucose tolerance at both baseline and follow-up.RESULTSThe cumulative incidence of NOD was 13.6% (9.3% in controls and 13.5% in treated patients). NOD was diagnosed after 3.4±1.8 years. In the group with normal glucose levels at baseline, a family history of diabetes (OR: 3.4, 95% CI 1.3–8.9), BMI >30 kg/m2 (OR: 8.5, 95% CI 2.0–35.8), treatment with thiazide (OR: 21.9, 95% CI 1.2–384.2) and no alcohol consumption (OR: 0.3, 95% CI 0.1–0.8) reduced the risk of developing altered glucose levels or NOD. No effects of statins were seen. In the group with altered glucose levels at baseline, hypertension (OR: 5.0, 95% CI 1.0–25.3) and hypertriglyceridemia (OR: 3.5, 95% CI 1.0–11.8) increased the risk of remaining with altered glucose levels or developing NOD. Treatment with statins (OR: 7.5, 95% CI 1.5–37.4), in particular atorvastatin, was associated with an increased risk. In the whole population, statin therapy (OR: 4.0, 95% CI 1.1–14.1, p<0.020), and in particular simvastatin and atorvastatin, was associated with increased risk of altered glucose levels or NOD. Patients who developed or maintained altered glucose levels or NOD had a poor metabolic phenotype at baseline.CONCLUSIONSStatins were associated with an increased risk of NOD or altered glucose levels, mainly in subjects with altered glucose levels before the beginning of therapy. Poor metabolic phenotype and unhealthy behaviors or family history of diabetes contributed to that risk.