Dyslipidemia seems to be less frequent than other metabolic comorbidities in human Cushing’s syndrome. Nevertheless, it plays an important role in determining the global cardiovascular risk in overt and subclinical Cushing’s syndrome. In Cushing’s syndrome, there is an increase of triglyceride and total cholesterol levels whereas HDL can be at variable levels. Overt and subclinical Cushing’s syndrome share many features with metabolic syndrome including insulin resistance, abnormal fasting glucose levels, hypertension, obesity and dyslipidemia. The pathogenetic mechanisms are multifactorial, including direct and indirect cortisol action on lipolysis, free fatty acid production and turnover, very-low-density lipoprotein synthesis and fatty accumulation in the liver. AMP-activated protein kinase mediates many of glucocorticoid-induced metabolic changes. Insulin resistance plays a key role in determining lipid abnormalities. Other hormonal changes are involved including growth hormone, testosterone in men and estrogen in women, catecholamines and cytokines. In vitro, cortisol increases lipoprotein lipase in adipose tissues and particularly in visceral fat where lipolysis is activated, resulting in the release of free fatty acids into the circulation. The increase of free fatty acids may enhance the accumulation of hepatic lipids reducing glucose uptake and activating various serine kinases which results in decreased insulin signaling. Moreover, mice with a liver-specific disruption of the glucocorticoid receptor had diminished hepatic triglycerides levels. In humans, a high prevalence (up to 20%) of hepatic steatosis was also reported in patients with Cushing’s syndrome. Genetic variations in the glucocorticoid receptors may also affect the activity of cortisol, lipid metabolism and cardiovascular risk.

Objective: Corticotropin releasing hormone (CRH) test does not reliably distinguish Cushing's disease (CD) from normality or pseudo-Cushing state (PC). We assessed whether this could be achieved with a novel approach while preserving the ability of the test to distinguish CD from ectopic ACTH syndrome (EAS). Design: Retrospective/prospective study. Subjects and methods: We studied 51 subjects with CD, 7 with EAS, 26 with PC, and 31 controls (CT). Human CRH (hCRH) test was performed at 0830 h by measuring plasma ACTH and serum cortisol at K15, 0, 15, 30, 45, 60, 90, and 120 min. Results: The area under the curve-ACTH exhibited a significant negative correlation with baseline serum cortisol in CT and PC, but not in CD or EAS patients. ACTH response to hCRH was blunted in PC compared with CT, whereas peak serum cortisol was higher in PC than in CT subjects. These findings suggested that ACTH-dependent Cushing's syndrome can be diagnosed by the presence of two hCRH test parameters and excluded if either or both are absent. Application of i) basal serum cortisol O12 mg/dl and peak plasma ACTH O54 pg/ml, or ii) peak serum cortisol O21 mg/dl and peak plasma ACTH O45 pg/ml, had 91.3% (95% confidence intervals (CI) 81-97.1) and 94.8% (CI 85.6-98.9) sensitivity and 98.2% (CI 90.6-99.9) and 91.2% (CI 80.7-97) specificity respectively, in diagnosing ACTH-dependent Cushing's syndrome. The O14% serum cortisol increase from mean baseline values to the mean of 15 and 30 min values in patients who were positive for the test completely discriminated between CD and EAS. Conclusions: Simultaneous plasma ACTH and serum cortisol analysis enables the hCRH test to distinguish CD from PC and from normality, while preserving its ability to discriminate CD from EAS.

Objective: Glucocorticoid receptor (GR) polymorphisms alter glucocorticoid (GC) sensitivity and have been associated with altered metabolic profiles. We evaluate the prevalence of the four GR (NR3C1) polymorphisms BclI, N363S, ER22/23EK, and A3669G in patients with Cushing's syndrome (CS) compared with healthy controls (HC) and we investigate their role in the development of metabolic abnormalities in patients with CS according to their hormonal profile. Patients and methods: Sixty-one patients with CS and 71 sex-and age-matched HC were genotyped. Results: BclI variant was markedly higher in patients with CS compared with HC (62 vs 41%, P!0.05) while no significant differences were found among other polymorphisms. A very low frequency of N363S and the ER22/23EK was observed. In CS patients, despite the significantly increased levels of morning serum cortisol in BclI carriers compared with wild type no clinical or metabolic differences were found. In contrast, A3669G GR carriers showed a significantly reduced prevalence of type 2 diabetes mellitus compared with wild type (19 vs 68%, PZ0.001) despite the higher levels of both serum morning (21.7G6 vs 27.3G8.6 mg/dl, PZ0.009) and midnight cortisol (18.8G5.8 vs 24.0G8.0 mg/dl, PZ0.01). The negative association between diabetes and A3669G GR polymorphism remained significant when data were adjusted for potential confounding factors. Conclusions: The A3669G polymorphism of the GR gene plays a protective role in patients with CS, attenuating the effects of GC excess on glucose metabolism as shown by their reduced risk of diabetes.

This case presentation indicates that uncontrolled UFC levels during the first few months of pasireotide treatment as well as worsening of glycemic control in patients with CD and DM are not always predictive of the efficacy and tolerability and appears to support the long-term continuation of pasireotide.

In patients with CD, pasireotide rapidly reduced and normalized both UFC and LNSC levels. LNSC may be a simple, non-invasive biomarker to assess the early response to pasireotide, particularly in determining whether cortisol rhythm is normalized in patients with normalized UFC levels. Further studies are warranted.