Laura Trementino

Pathophysiology of dyslipidemia in Cushing's syndrome.

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.

Advances in the epidemiology, pathogenesis, and management of Cushing's syndrome complications.

Cushing’s syndrome (CS) is a clinical condition resulting from chronic exposure to glucocorticoid excess. As a consequence, hypercortisolism contributes significantly to the early development of systemic disorders by direct and/or indirect effects. Complications such as obesity, hypertension, diabetes, dyslipidemia, and hypercoagulability cause premature atherosclerosis and increase cardiovascular mortality. Impairment of the skeletal system is a relevant cause of morbidity and disability in these patients especially due to the high prevalence of vertebral fractures. In addition, muscle weakness, emotional lability, depression, and impairment of quality of life are very common. Clinical management of these patients is complex and should be particularly careful in identifying global cardiovascular risks and aim at controlling all complications. Although the primary goal in the prevention and treatment of complications is the correction of hypercortisolism, treatment does not completely eliminate these comorbidities. Given that cardiovascular risk and fracture risk can persist after cure, early detection of each morbidity could prevent the development of irreversible damage. In this review we present the various complications of CS and their pathogenetic mechanisms. We also suggest the clinical management of these patients based on our extensive clinical experience and on the available literature.

Coagulopathy in Cushing’s Syndrome

A hypercoagulable state and its consequent increased incidence of thromboembolic complications are reported in patients with Cushing’s syndrome (CS). These alterations are related to cortisol excess that induces prothrombotic changes in blood by several and complex mechanisms including increased levels of clotting factors, mainly factor VIII and von Willebrand factor (VWF) and impaired fibrinolytic capacity. However, it has recently been observed that the increase in VWF levels is not a constant feature of CS and that VWF response to glucocorticoids is genetically determined and depends on the presence of particular polymorphisms in the VWF gene promoter. The risk of venous thromboembolism is moreover enhanced in patients with CS by additional endogenous and exogenous risk factors such as obesity, bed rest, surgery and invasive diagnostic procedures like inferior petrosal sinus (IPS) sampling. In line with all these data, patients with active CS should be treated as having a prothrombotic disorder and undergo antithrombotic prophylaxis during IPS sampling. Special care should be taken in the immediate perioperative period in order to avoid thromboembolic events. In the absence of prospective randomized trials, preventive antithrombotic treatment (best with heparin) during IPS sampling and low-dose heparin treatment early after surgery should be suggested.

Treatment-related fatigue with sorafenib, sunitinib and pazopanib in patients with advanced solid tumors: an up-to-date review and meta-analysis of clinical trials.

Fatigue is the most common symptom associated with cancer and cancer treatment. We performed an up‐to‐date meta‐analysis to determine the incidence and relative risk (RR) of fatigue in patients (pts) with cancer treated with sorafenib (SO), sunitinib (SU) and pazopanib (PZ). PubMed databases were searched for articles published till August 2013. Eligible studies were selected according to PRISMA statement. Summary incidence, RR and 95% confidence intervals were calculated using random‐effects or fixed‐effects models based on the heterogeneity of selected studies. Fifteen studies were included in our analysis. A total of 6,996 pts was enrolled: 2,260 had renal cell carcinomas (RCC), 1,691 non‐small cell lung cancers, 1,290 breast cancers, 823 hepatocellular carcinomas, 362 soft tissue sarcomas, 304 gastrointestinal solid tumors, 165 neuroendocrine tumors and 101 melanomas. When stratified by drug, SO registered lower incidence and RR of all and high‐grade fatigue when compared to SU, whereas the difference between SO and PZ was significant only for all‐grade fatigue (p < 0.001). The difference between SU and PZ was significant for high‐grade (p < 0.001) but not for all‐grade fatigue (p = 0.52). In RCC pts, PZ showed the lower incidence and RR of all and high‐grade fatigue. The differences were significant for SU vs. SO (p < 0.001), SU vs. PZ (p < 0.001) and SO vs. PZ (p < 0.001). Treatment with SO, SU and PZ is associated with an increased incidence of fatigue in pts with cancer. Early and appropriate management is required to avoid unnecessary dose reductions and transitory or definitive treatment discontinuations.

Human corticotropin releasing hormone test performance in the differential diagnosis between Cushing's disease and pseudo-Cushing state is enhanced by combined ACTH and cortisol analysis

OBJECTIVE Corticotropin releasing hormone (CRH) test does not reliably distinguish Cushings 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 -15, 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 Cushings 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 >12 microg/dl and peak plasma ACTH >54 pg/ml, or ii) peak serum cortisol >21 microg/dl and peak plasma ACTH >45 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 Cushings syndrome. The >14% 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.

Association of glucocorticoid receptor polymorphism A3669G with decreased risk of developing diabetes in patients with Cushing's syndrome.

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 Cushings 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%, P=0.001) despite the higher levels of both serum morning (21.7±6 vs 27.3±8.6 μg/dl, P=0.009) and midnight cortisol (18.8±5.8 vs 24.0±8.0 μg/dl, P=0.01). 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.

Bone complications in patients with Cushing's syndrome: looking for clinical, biochemical, and genetic determinants.

SummaryThis is the first study examining the impact of both clinical, biochemical, and genetic determinants in the occurrence of bone complications in patients with overt Cushing’s syndrome (CS). It demonstrates that the degree and duration of hypercortisolism seem to play a major role in bone loss and fractures development in these patients.IntroductionBone loss and fractures are a common complication of CS. We investigate the role of gender, disease etiology, duration, and degree of hypercortisolism as well as the impact of glucocorticoid receptor (GR) polymorphisms on the development of bone complications in CS.MethodsFifty-two patients with active CS (38 Cushing’s disease and 14 with cortisol-secreting adrenal adenoma) were genotyped for GR polymorphisms (BclI, N363S, ER22/23EK, and A3669G). In all patients, clinical, hormonal, and biochemical markers of bone turnover, densitometric parameters [lumbar spine and left femur bone mineral density (BMD), T-score, Z-score] as well as the prevalence of bone demineralization and both vertebral and peripheral fractures were assessed.ResultsNo differences were found in bone complications according to gender, disease etiology, and genetic variants distribution. Fractured patients compared to non-fractured ones showed increased levels of urinary free cortisol (UFC) and a more compromised densitometric profile. UFC levels correlated with the occurrence of vertebral fractures (r = 0.43, p = 0.009) while midnight serum cortisol correlated with L1–L4 BMD values (r = −0.35, p = 0.04). Disease duration correlated with the presence of peripheral fractures (r = 0.36, p = 0.04).ConclusionsWhile GR gene variants as well as gender and disease etiology seem not to play a role, the degree and duration of hypercortisolism seem to be the major determinants of bone loss and fractures in this group of patients. More investigations are needed to understand the real impact of these determinants on the development of bone complications in patients with hypercortisolism.

Hypercoagulability in patients with Cushing disease detected by thrombin generation assay is associated with increased levels of neutrophil extracellular trap-related factors

Patients with Cushing disease (CD) are at increased risk of venous thromboembolism (VTE). It was surmised, but not conclusively shown that the risk is related to plasma hypercoagulability secondary to the glucocorticoids effect. This study is aimed at detecting hypercoagulability in patients with CD. Case-control study of 48 CD patients and controls enrolled at two Italian clinics for whom we assessed the thrombin-forming-potential in the presence of optimal activation of protein C obtained by adding into the assay system its main endothelial activator, thrombomodulin. These experimental conditions mimic more closely than any other test the in vivo situation. We observed enhanced thrombin-generation in CD patients, as shown by the modification of thrombin-generation parameters [i.e., shortened lag-time and time-to-peak, increased thrombin peak and endogenous thrombin potential (ETP)]. Moreover, the ETP ratio (with/without thrombomodulin), recognized as an index of hypercoagulability, was increased in patients as compared to controls. We attempted to explain such hypercoagulability by measuring both procoagulant and anticoagulant factors, and some other non-coagulation parameters (i.e., neutrophil extracellular traps (NET), recently associated with the VTE risk and/or increased hypercoagulability. We showed that the hypercoagulability in patients with CD is associated with increased levels of factor VIII and NET-related variables. We detected plasma hypercoagulability in patients with CD and found experimental explanation for its occurrence. Whether this hypercoagulability can entirely explain the occurrence of VTE in patients with CD should be investigated by ad-hoc clinical trials. However, until these studies will be available the evidence supports the concept that patients with CD are candidates for antithrombotic prophylaxis.

Pituitary adenomas, stem cells, and cancer stem cells: what’s new?

PurposeTo clarify the existence of pituitary stem cells (SCs) both in the embryonic and the postnatal gland and the role for SCs in pituitary adenomas. MethodsThis work, which does not address the pathogenesis of pituitary adenomas, reviews the latest research findings and discoveries on SCs in pituitary and cancer SCs (CSCs) in pituitary adenomas and discusses the involvement of the EMT.ResultsSeveral groups using different approaches and techniques have demonstrated the existence of SCs and CSCs and as they are major players in pituitary adenoma onset.ConclusionsAs in other benign and malignant tumors, the hypothesis that CSCs play a pivotal role in pituitary adenoma onset has been confirmed as well as the existence of a link between the epithelial-to-mesenchymal transition (EMT) process and CSC formation in epithelial tumors.

Diagnostic accuracy of increased urinary cortisol/cortisone ratio to differentiate ACTH-dependent Cushing's syndrome

Differential diagnosis between Cushings Disease (CD) and Ectopic ACTH Syndrome (EAS) may be a pitfall for endocrinologists. The increasing use in clinical practice of chromatography and mass spectrometry improves the measurement of urinary free cortisol (UFF) and cortisone (UFE). We have recently observed that cortisol to cortisone ratio (FEr) was higher in a small series of EAS; in this study we collected a larger number of ACTH‐dependent Cushings Syndrome (CS) to study the role of FEr to characterize the source of corticotropin secretion.