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

Cortisol secretion and abnormalities of glucose metabolism in nondiabetic patients with hypertension

OBJECTIVE

Glycometabolic changes are associated with hypercortisolism in Cushing's syndrome. Because impaired glucose tolerance (IGT) and insulin resistance are frequently detected in patients with essential hypertension, we hypothesized that in these patients, early glycometabolic abnormalities might be related to differences in regulation of cortisol secretion.

METHODS

In a cross-sectional study, we included 155 nondiabetic, essential hypertensive patients who were free of organ complications. The homeostasis model assessment (HOMA) index and the area under the curve of plasma glucose (AUC-glucose) and insulin (AUC-insulin) concentration following an oral glucose tolerance test were measured, together with daily plasma cortisol (8 a.m., 3 p.m. and 12 a.m.; AUC-cortisol) and 8 a.m. cortisol after 1 mg overnight dexamethasone suppression test (DST).

RESULTS

IGT was present in 27% of patients who were older and had higher BMI, plasma triglycerides and uric acid, AUC-cortisol and DST-cortisol, and lower HDL-cholesterol. Frequency of IGT increased progressively across tertiles of DST-cortisol, together with levels of glycated hemoglobin, fasting insulin and C-peptide, HOMA-index, AUC-glucose, and AUC-insulin. AUC-cortisol and DST-cortisol were directly correlated with insulin, C-peptide, HOMA-index, AUC-glucose, and AUC-insulin. Multivariate regression analysis showed that DST-cortisol was directly and independently correlated with HOMA index, AUC-glucose, and AUC-insulin. In a logistic regression model, both AUC-cortisol and DST-cortisol independently predicted IGT.

CONCLUSION

Daily cortisol and cortisol response to DST are independent determinants of IGT and insulin resistance in nondiabetic patients with hypertension, suggesting that even subtle differences in regulation of cortisol secretion might increase the risk of these patients to develop diabetes.

Cushing Syndrome in Childhood

We describe a 15-year-old boy who presented with low back pain due to vertebral compression fractures, growth deceleration, excessive weight gain, rounded facies, dorsocervical fat pad, and hypertension. He was diagnosed as having Cushing syndrome (CS) due to primary pigmented nodular adrenocortical disease resulting in excess cortisol produced by the adrenal glands, leading to disruption of the hypothalamic-pituitary-adrenal axis. The most common cause of CS is exogenous glucocorticoids, with endogenous causes being extremely rare, often leading to delay in diagnosis or misdiagnosis. Herein, we review clinical presentation, screening for hypercortisolism, and decision-making in the diagnosis of CS, as well as therapeutic approaches. The wide range of clinical presentations in pediatric CS and the rarity of the condition can lead to difficulty in the recognition, diagnosis, and subsequent management of these patients. CS can be difficult to differentiate from more common exogenous obesity, and outpatient screening of cortisol excess is challenging. Early recognition and treatment of CS is necessary to avoid multisystemic complications, and patients with suspected endogenous CS should be referred to a tertiary care center with experienced pediatric endocrinology and surgery specialists. Further confirmatory diagnostic tests are necessary to distinguish corticotropin-independent from corticotropin-dependent forms of CS, including a high-dose dexamethasone suppression test, a corticotropin-releasing hormone stimulation test, and imaging. There can be challenges to the evaluation of CS, including complex inpatient testing and difficulty with localization on imaging. Long-term sequelae of CS, including adrenal insufficiency, obesity, hypertension, and mental health disorders, may remain despite definitive surgical treatment, meriting close follow-up with the primary care clinician and subspecialists.

Glucocorticoid Receptor Antagonism Improves Glucose Metabolism in a Mouse Model of Polycystic Ovary Syndrome

Context

Polycystic ovary syndrome (PCOS) is a complex metabolic disorder associated with obesity, insulin resistance, and dyslipidemia. Hyperandrogenism is a major characteristic of PCOS. Increased androgen exposure is believed to deregulate metabolic processes in various tissues as part of the PCOS pathogenesis, predominantly through the androgen receptor (AR). Notably, various metabolic features in PCOS are similar to those observed after excess glucocorticoid exposure.

Objective

We hypothesized that glucocorticoid receptor (GR) signaling is involved in the metabolic symptoms of PCOS.

Methods

In a PCOS model of chronic dihydrotestosterone (DHT) exposure in female mice, we investigated whether GR signaling machinery was (de)regulated, and if treatment with a selective GR antagonist alleviated the metabolic symptoms.

Results

We observed an upregulation of GR messenger RNA expression in the liver after DHT exposure. In white adipose tissues and liver we found that DHT upregulated Hsd11b1, which encodes for the enzyme that converts inactive into active glucocorticoids. We found that preventive but not therapeutic administration of a GR antagonist alleviated DHT-induced hyperglycemia and restored glucose tolerance. We did not observe strong effects of GR antagonism in DHT-exposed mice on other features like total fat mass and lipid accumulation in various tissues.

Conclusion

We conclude that GR activation may play a role in glucose metabolism in DHT-exposed mice.

Practical therapeutic approach in the management of diabetes mellitus secondary to Cushing's syndrome, acromegaly and neuroendocrine tumours

Cushing's syndrome, acromegaly and neuroendocrine disorders are characterized by an excess of counterregulatory hormones, able to induce insulin resistance and glucose metabolism disorders at variable degrees and requiring immediate treatment, until patients are ready to undergo surgery. This review focuses on the management of diabetes mellitus in endocrine disorders related to an excess of counterregulatory hormones. Currently, the landscape of approved agents for treatment of diabetes is dynamic and is mainly patient-centred and not glycaemia-centred. In addition, personalized medicine is more and more required to provide a precise approach to the patient's disease. For this reason, we aimed to define a practical therapeutic algorithm for management of diabetes mellitus in patients with glucagonoma, pheochromocytoma, Cushing's syndrome and acromegaly, based on our practical experience and on the physiopathology of the specific endocrine disease taken into account. This document is addressed to all specialists who approach patients with diabetes mellitus secondary to endocrine disorders characterized by an excess of counterregulatory hormones, in order to take better care of these patients. Care and control of diabetes mellitus should be one of the primary goals in patients with an excess of counterregulatory hormones requiring immediate and aggressive treatment.

Relationship Between Appetite-Related Peptides and Frailty in Older Adults

BACKGROUND

Frailty, is a geriatric syndrome that reduces the resistance to stress situations caused by activities of daily living and increases morbidity and mortality. We hypothesized that a decrease in orexigenic peptides or an increase in anorexigenic peptides might be associated with frailty. We aimed to investigate the relationship between frailty and six appetite-related peptides: ghrelin, neuropeptide Y (NPY), agouti-related peptide (AgRP), cocaine-amphetamine-associated peptide (CART), peptide YY, and alpha MSH (α-MSH).

METHODS

This cross-sectional study was conducted on 85 older adults who visited the outpatient clinic. All patients underwent comprehensive geriatric assessment. Frailty status was assessed using the Fried frailty index. Plasma levels of six appetite-related peptides were studied.

RESULTS

The mean age was 73.7 ± 5.4 years, 27 (31.8%) of the patients were male, and 32 of the patients (37.6%) were frail. While plasma levels of ghrelin, NPY and AgRP were significantly lower in frail patients, CART and α-MSH levels were higher compared to non-frail patients (p < .05 for all). Peptide YY was found to be higher in the frail group, however, the difference did not reach statistical significance (p = .052). In multivariate logistic regression analysis, the ghrelin, AgRP, CART, and α-MSH levels were independent predictors of frailty. Moreover, a weak correlation was found between all peptides(except NPY) and handgrip strength and Lawton-Brody score.

CONCLUSION

Ghrelin, AgRP, CART, and α-MSH levels were found to be independent predictors of frailty. Our results suggest that appetite-related peptides might be playing roles in the pathogenesis of frailty. Further larger prospective studies are needed to test this hypothesis.

Medical treatment of Cushing's disease with concurrent diabetes mellitus

Cushing's disease (CD) is a severe endocrine disorder characterized by chronic hypercortisolaemia secondary to an overproduction of adrenocorticotropic hormone (ACTH) by a pituitary adenoma. Cortisol excess impairs normal glucose homeostasis through many pathophysiological mechanisms. The varying degrees of glucose intolerance, including impaired fasting glucose, impaired glucose tolerance, and Diabetes Mellitus (DM) are commonly observed in patients with CD and contribute to significant morbidity and mortality. Although definitive surgical treatment of ACTH-secreting tumors remains the most effective therapy to control both cortisol levels and glucose metabolism, nearly one-third of patients present with persistent or recurrent disease and require additional treatments. In recent years, several medical therapies demonstrated prominent clinical efficacy in the management of patients with CD for whom surgery was non-curative or for those who are ineligible to undergo surgical treatment. Cortisol-lowering medications may have different effects on glucose metabolism, partially independent of their role in normalizing hypercortisolaemia. The expanding therapeutic landscape offers new opportunities for the tailored therapy of patients with CD who present with glucose intolerance or DM, however, additional clinical studies are needed to determine the optimal management strategies. In this article, we discuss the pathophysiology of impaired glucose metabolism caused by cortisol excess and review the clinical efficacy of medical therapies of CD, with particular emphasis on their effects on glucose homeostasis.

Effects of Anterior Pituitary Adenomas' Hormones on Glucose Metabolism and Its Clinical Implications

Pituitary adenomas have recently become more common and their incidence is increasing yearly. Functional pituitary tumors commonly secrete prolactin, growth hormones, and adrenocorticotropic hormones, which cause diseases such as prolactinoma, acromegaly, and Cushing's disease, but rarely secrete luteinizing, follicle-stimulating, thyroid-stimulating, and melanocyte-stimulating hormones. In addition to the typical clinical manifestations of functional pituitary tumors caused by excessive hormone levels, some pituitary tumors are also accompanied by abnormal glucose metabolism. The effects of these seven hormones on glucose metabolism are important for the treatment of diabetes secondary to pituitary tumors. This review focuses on the effects of hormones on glucose metabolism, providing important clues for the diagnosis and treatment of related diseases.

Clinical, pathophysiologic, genetic and therapeutic progress in Primary Bilateral Macronodular Adrenal Hyperplasia

Patients with primary bilateral macronodular adrenal hyperplasia (PBMAH) usually present bilateral benign adrenocortical macronodules at imaging and variable levels of cortisol excess. PBMAH is a rare cause of primary overt Cushing's syndrome, but may represent up to one third of bilateral adrenal incidentalomas with evidence of cortisol excess. The increased steroidogenesis in PBMAH is often regulated by various G-protein coupled receptors aberrantly expressed in PBMAH tissues; some receptor ligands are ectopically produced in PBMAH tissues creating aberrant autocrine/paracrine regulation of steroidogenesis. The bilateral nature of PBMAH and familial aggregation, led to the identification of germline heterozygous inactivating mutations of the ARMC5 gene, in 20-25% of the apparent sporadic cases and more frequently in familial cases; ARMC5 mutations/pathogenic variants can be associated with meningiomas. More recently, combined germline mutations/pathogenic variants and somatic events inactivating the KDM1A gene were specifically identified in patients affected by GIP-dependent PBMAH. Functional studies demonstrated that inactivation of KDM1A leads to GIP-receptor (GIPR) overexpression and over or down-regulation of other GPCRs. Genetic analysis is now available for early detection of family members of index cases with PBMAH carrying identified germline pathogenic variants. Detailed biochemical, imaging, and co-morbidities assessment of the nature and severity of PBMAH is essential for its management. Treatment is reserved for patients with overt or mild cortisol/aldosterone or other steroid excesses taking in account co-morbidities. It previously relied on bilateral adrenalectomy; however recent studies tend to favor unilateral adrenalectomy, or less frequently, medical treatment with cortisol synthesis inhibitors or specific blockers of aberrant GPCR.

Animal Models of Cushing's Syndrome

Endogenous Cushing's syndrome is characterized by unique clinical features and comorbidities, and progress in the analysis of its genetic pathogenesis has been achieved. Moreover, prescribed glucocorticoids are also associated with exogenous Cushing's syndrome. Several animal models have been established to explore the pathophysiology and develop treatments for Cushing's syndrome. Here, we review recent studies reporting animal models of Cushing's syndrome with different features and complications induced by glucocorticoid excess. Exogenous corticosterone (CORT) administration in drinking water is widely utilized, and we found that CORT pellet implantation in mice successfully leads to a Cushing's phenotype. Corticotropin-releasing hormone overexpression mice and adrenal-specific Prkar1a-deficient mice have been developed, and AtT20 transplantation methods have been designed to examine the medical treatments for adrenocorticotropic hormone-producing pituitary neuroendocrine tumors. We also review recent advances in the molecular pathogenesis of glucocorticoid-induced complications using animal models.

Fresh insights into glucocorticoid-induced diabetes mellitus and new therapeutic directions

Glucocorticoid hormones were discovered to have use as potent anti-inflammatory and immunosuppressive therapeutics in the 1940s and their continued use and development have successfully revolutionized the management of acute and chronic inflammatory diseases. However, long-term use of glucocorticoids is severely hampered by undesirable metabolic complications, including the development of type 2 diabetes mellitus. These effects occur due to glucocorticoid receptor activation within multiple tissues, which results in inter-organ crosstalk that increases hepatic glucose production and inhibits peripheral glucose uptake. Despite the high prevalence of glucocorticoid-induced hyperglycaemia associated with their routine clinical use, treatment protocols for optimal management of the metabolic adverse effects are lacking or underutilized. The type, dose and potency of the glucocorticoid administered dictates the choice of hypoglycaemic intervention (non-insulin or insulin therapy) that should be provided to patients. The longstanding quest to identify dissociated glucocorticoid receptor agonists to separate the hyperglycaemic complications of glucocorticoids from their therapeutically beneficial anti-inflammatory effects is ongoing, with selective glucocorticoid receptor modulators in clinical testing. Promising areas of preclinical research include new mechanisms to disrupt glucocorticoid signalling in a tissue-selective manner and the identification of novel targets that can selectively dissociate the effects of glucocorticoids. These research arms share the ultimate goal of achieving the anti-inflammatory actions of glucocorticoids without the metabolic consequences.

Long-term morbidity and mortality in patients with Cushing's syndrome

Increased multisystem morbidity and mortality in patients with Cushing's syndrome comprise clinical problems and challenges, both at the time of diagnosis and in remission. Relevant comorbidities and clinical problems include hypertension, diabetes, overweight, myopathy and a high risk for acute complications such as infections and venous thrombembolism. Although there are therapy recommendations for most of these comorbidities, there is a lack of large, prospective studies to confirm and optimise them. Mortality is especially high during active disease and within the first year after diagnosis, as a result of cardiovascular events, infections and suicide. All in all, interdisciplinary therapy management is important for reducing morbidity and mortality over the long-term.

Glucose and lipid metabolism abnormalities in Cushing's syndrome

Prolonged excess of glucocorticoids (GCs) has adverse systemic effects leading to significant morbidities and an increase in mortality. Metabolic alterations associated with the high level of the GCs are key risk factors for the poor outcome. These include GCs causing excess gluconeogenesis via upregulation of key enzymes in the liver, a reduction of insulin sensitivity in skeletal muscle, liver and adipose tissue by inhibiting the insulin receptor signalling pathway, and inhibition of insulin secretion in beta cells leading to dysregulated glucose metabolism. In addition, chronic GC exposure leads to an increase in visceral adipose tissue, as well as an increase in lipolysis resulting in higher circulating free fatty acid levels and in ectopic fat deposition. Remission of hypercortisolism improves these metabolic changes, but very often does not result in full resolution of the abnormalities. Therefore, long-term monitoring of metabolic variables is needed even after the resolution of the excess GC levels.

β-cell function and insulin sensitivity contributions on incident diabetes in patients with endogenous Cushing's syndrome

OBJECTIVE

To evaluate the relative contributions of β-cell function and insulin sensitivity on the deterioration of glucose tolerance from OGTT in patients with endogenous CS.

METHODS

We retrospectively analyzed the data of 60 patients with CS and determined the glucose metabolism and β-cell function through OGTT. Their general characteristics were retrieved. A series of parameters for assessing insulin sensitivity and β-cell function was calculated. The logistic regression model was used to investigate insulin sensitivity and β-cell function contributions on incident diabetes.

RESULTS

Of the 60 patients with CS, 10 (16.7%), 21 (35%), and 29 (48.3%) were classified as CS/ normal glucose tolerance (NGT), CS/prediabetes, and CS/diabetes mellitus (DM). Compared with the HCs, the CS/NGT patients had higher HOMA-IR and lower ISI-Matsuda but with a compensatory increase in HOMA-β. Significant decreasing trends were observed in HOMA-β, AUC_I/G and ΔI₃₀/ΔG₃₀ among CS/NGT, CS/prediabetes and CD/DM groups. The OR of incident diabetes compared with the high AUC_I/G/high ISI group was significant in the low AUC_I/G/high ISI group.

CONCLUSION

Impairment of the β-cell function had a more profound effect on incident diabetes than decreased insulin sensitivity. An approach based on an OGTT has utility for diagnosing dysglycaemia and β-cell dysfunction in patients with CS.

Very Low-Calorie Ketogenic Diet: A Potential Application in the Treatment of Hypercortisolism Comorbidities

A very low-calorie ketogenic diet (VLCKD) is characterized by low daily caloric intake (less than 800 kcal/day), low carbohydrate intake (<50 g/day) and normoproteic (1−1.5 g of protein/kg of ideal body weight) contents. It induces a significant weight loss and an improvement in lipid parameters, blood pressure, glycaemic indices and insulin sensitivity in patients with obesity and type 2 diabetes mellitus. Cushing’s syndrome (CS) is characterized by an endogenous or exogenous excess of glucocorticoids and shows many comorbidities including cardiovascular disease, obesity, type 2 diabetes mellitus and lipid disorders. The aim of this speculative review is to provide an overview on nutrition in hypercortisolism and analyse the potential use of a VLCKD for the treatment of CS comorbidities, analysing the molecular mechanisms of ketogenesis.

Pasireotide-a novel somatostatin receptor ligand after 20 years of use

Pasireotide, a novel multireceptor-targeted somatostatin receptor ligand (SRL) is characterized by a higher affinity to somatostatin receptor type 5 than type 2, unlike first-generation SRLs. Because of the broader binding profile, pasireotide has been suggested to have a greater clinical efficacy in acromegaly than first-generation SRLs and to be efficacious in Cushing's disease. The consequence of this binding profile is the increased blood glucose level in some patients. This results from the inhibition of both insulin secretion and the incretin effect and only a modest suppression of glucagon. A monthly intramuscular formulation of long-acting release pasireotide has been approved for both acromegaly and Cushing's disease treatment. This review presents data on the efficacy and safety of pasireotide treatment mostly in patients with acromegaly and Cushing's disease. Moreover, other possible therapeutic applications of pasireotide are mentioned.

Incretin Response to Mixed Meal Challenge in Active Cushing's Disease and after Pasireotide Therapy

Cushing’s disease (CD) causes diabetes mellitus (DM) through different mechanisms in a significant proportion of patients. Glucose metabolism has rarely been assessed with appropriate testing in CD; we aimed to evaluate hormonal response to a mixed meal tolerance test (MMTT) in CD patients and analyzed the effect of pasireotide (PAS) on glucose homeostasis. To assess gastro-entero-pancreatic hormones response in diabetic (DM+) and non-diabetic (DM−) patients, 26 patients with CD underwent an MMTT. Ten patients were submitted to a second MMTT after two months of PAS 600 µg twice daily. The DM+ group had significantly higher BMI, waist circumference, glycemia, HbA1c, ACTH levels and insulin resistance indexes than DM− (p < 0.05). Moreover, DM+ patients exhibited increased C-peptide (p = 0.004) and glucose area under the curve (AUC) (p = 0.021) during MMTT, with a blunted insulinotropic peptide (GIP) response (p = 0.035). Glucagon levels were similar in both groups, showing a quick rise after meals. No difference in estimated insulin secretion and insulin:glucagon ratio was found. After two months, PAS induced an increase in both fasting glycemia and HbA1c compared to baseline (p < 0.05). However, this glucose trend after meal did not worsen despite the blunted insulin and C-peptide response to MMTT. After PAS treatment, patients exhibited reduced insulin secretion (p = 0.005) and resistance (p = 0.007) indexes. Conversely, glucagon did not change with a consequent impairment of insulin:glucagon ratio (p = 0.009). No significant differences were observed in incretins basal and meal-induced levels. Insulin resistance confirmed its pivotal role in glucocorticoid-induced DM. A blunted GIP response to MMTT in the DM+ group might suggest a potential inhibitory role of hypercortisolism on enteropancreatic axis. As expected, PAS reduced insulin secretion but also induced an improvement in insulin sensitivity as a result of cortisol reduction. No differences in incretin response to MMTT were recorded during PAS therapy. The discrepancy between insulin and glucagon trends while on PAS may be an important pathophysiological mechanism in this iatrogenic DM; hence restoring insulin:glucagon ratio by either enhancing insulin secretion or reducing glucagon tone can be a potential therapeutic target.

Vitamin D Deficiency in Cushing's Disease: Before and After Its Supplementation

Background: The primary objective of the study was to assess serum 25-hydroxyvitamin D [25(OH)D] values in patients with Cushing’s disease (CD), compared to controls. The secondary objective was to assess the response to a load of 150,000 U of cholecalciferol. Methods: In 50 patients with active CD and 48 controls, we evaluated the anthropometric and biochemical parameters, including insulin sensitivity estimation by the homeostatic model of insulin resistance, Matsuda Index and oral disposition index at baseline and in patients with CD also after 6 weeks of cholecalciferol supplementation. Results: At baseline, patients with CD showed a higher frequency of hypovitaminosis deficiency (p = 0.001) and lower serum 25(OH)D (p < 0.001) than the controls. Six weeks after cholecalciferol treatment, patients with CD had increased serum calcium (p = 0.017), 25(OH)D (p < 0.001), ISI-Matsuda (p = 0.035), oral disposition index (p = 0.045) and decreased serum PTH (p = 0.004) and total cholesterol (p = 0.017) values than at baseline. Multivariate analysis showed that mean urinary free cortisol (mUFC) was independently negatively correlated with serum 25(OH)D in CD. Conclusions: Serum 25(OH)D levels are lower in patients with CD compared to the controls. Vitamin D deficiency is correlated with mUFC and values of mUFC > 240 nmol/24 h are associated with hypovitaminosis D. Cholecalciferol supplementation had a positive impact on insulin sensitivity and lipids.

Irisin and Secondary Osteoporosis in Humans

Irisin is a peptide secreted by skeletal muscle following exercise that plays an important role in bone metabolism. Numerous experiments in vitro and in mouse models have shown that the administration of recombinant irisin promotes osteogenesis, protects osteocytes from dexamethasone-induced apoptosis, prevents disuse-induced loss of bone and muscle mass, and accelerates fracture healing. Although some aspects still need to be elucidated, such as the dose- and frequency-dependent effects of irisin in cell cultures and mouse models, ample clinical evidence is emerging to support its physiological relevance on bone in humans. A reduction in serum irisin levels, associated with an increased risk of osteoporosis and bone fractures, was observed in postmenopausal women and in both men and women during aging, Recently, cohort studies of subjects with secondary osteoporosis showed that these patients have lower circulating levels of irisin, suggesting that this myokine could be a novel marker to monitor bone quality in this disease. Although there are still few studies, this review discusses the emerging data that are highlighting the involvement of irisin in some diseases that cause secondary osteoporosis.

Glucocorticoid excess and COVID-19 disease

The pandemic of coronavirus disease (COVID-19), a disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is causing high and rapid morbidity and mortality. Immune system response plays a crucial role in controlling and resolving the viral infection. Exogenous or endogenous glucocorticoid excess is characterized by increased susceptibility to infections, due to impairment of the innate and adaptive immune system. In addition, diabetes, hypertension, obesity and thromboembolism are conditions overrepresented in patients with hypercortisolism. Thus patients with chronic glucocorticoid (GC) excess may be at high risk of developing COVID-19 infection with a severe clinical course. Care and control of all comorbidities should be one of the primary goals in patients with hypercortisolism requiring immediate and aggressive treatment. The European Society of Endocrinology (ESE), has recently commissioned an urgent clinical guidance document on management of Cushing's syndrome in a COVID-19 period. In this review, we aim to discuss and expand some clinical points related to GC excess that may have an impact on COVID-19 infection, in terms of both contagion risk and clinical outcome. This document is addressed to all specialists who approach patients with endogenous or exogenous GC excess and COVID-19 infection.

Metabolic comorbidities of adrenal insufficiency: Focus on steroid replacement therapy and chronopharmacology

Adrenal insufficiency (AI) is characterized by higher mortality and morbidity compared with the general population. Conventional replacement steroid therapy, currently recommended for the treatment of AI, is associated with increased frequency of metabolic comorbidities due to daily overexposure. By contrast, dual-release hydrocortisone is associated with a decreased risk of metabolic comorbidities, providing an adequate release of hydrocortisone and mimicking the physiological profile of cortisol. These favorable effects are due to a reduced daily steroid exposure that does not affect the expression of the clock genes which are involved in metabolic pathways and are regulated by the normal physiological circadian rhythm of endogenous cortisol. This narrative review focuses on the possible metabolic comorbidities of AI due to steroid replacement therapy, which evaluates the effects of conventional and novel drugs with attention to chronopharmacology.

Levoketoconazole in the Treatment of Patients With Cushing's Syndrome and Diabetes Mellitus: Results From the SONICS Phase 3 Study

Background

Cushing's syndrome (CS) is associated with numerous comorbidities, including diabetes mellitus (DM). Levoketoconazole, an orally administered ketoconazole stereoisomer, is in clinical trials for the treatment of CS.

Methods

SONICS, a prospective, open-label, phase 3 study in adults with confirmed CS and mean 24-h urinary free cortisol (mUFC) ≥1.5× ULN, included dose-titration, 6-month maintenance, and 6-month extension phases. This subanalysis evaluated the efficacy of levoketoconazole in patients with DM (n = 28) or without DM (n = 49) who entered the maintenance phase. Safety was evaluated in the overall population (N = 94) during the dose-titration and maintenance phases.

Results

Normalization of mUFC at the end of maintenance phase (EoM), without a dose increase during maintenance (SONICS primary endpoint) was observed in 46% of patients with DM (95% CI, 28 to 66%; P = 0.0006 vs null hypothesis of ≤20%) and 33% of patients without DM (95% CI, 20 to 48%; P = 0.0209). At EoM, mean HbA1c decreased from 6.9% at baseline to 6.2% in patients with DM and from 5.5 to 5.3% in patients without DM. Mean fasting blood glucose decreased from 6.85 mmol/L (123.4 mg/dl) to 5.82 mmol/L (104.9 mg/dl) and from 5.11 mmol/L (92.1 mg/dl) to 4.66 mmol/L (84.0 mg/dl) in patients with and without DM, respectively. Adverse events that were more common in patients with DM included nausea (58.3%), vomiting (19.4%), and urinary tract infection (16.7%); none prompted study drug withdrawal.

Conclusions

Treatment with levoketoconazole led to sustained normalization of mUFC and improvement in glycemic control that was more pronounced in patients with DM.

Clinical Trial Registration

(ClinicalTrials.gov), NCT01838551.

Ectopic ACTH- and/or CRH-Producing Pheochromocytomas

CONTEXT

The characteristics of catecholamine-secreting pheochromocytomas have been well studied. However, less is known about the characteristics, management and outcome in patients with ectopic adrenocorticotropic hormone (ACTH) and/or corticotrophin-releasing hormone (CRH)-secreting pheochromocytomas.

OBJECTIVE

To review the characteristics and outcomes of ACTH- and/or CRH-secreting pheochromocytomas.

DATA SOURCE

A systematic search of PubMed/MEDLINE and Web of Science, identifying relevant reports published up to 10 February 2020.

STUDY SELECTION

Original articles, including case reports and case series, reporting individual patient data from patients with ACTH- and/or CRH-secreting pheochromocytomas.

DATA EXTRACTION

Information on sex, age, symptoms at presentation, comorbidities, biochemistry, imaging, histopathology, and outcomes was extracted.

DATA SYNTHESIS

We identified 91 articles reporting on 99 cases of ACTH- and/or CRH-secreting pheochromocytomas (CRH-secreting n = 4). Median age at diagnosis was 49 years (interquartile range 38-59.5) with a 2:1 female to male ratio. Most patients presented with clinical Cushing syndrome (n = 79; 81%), hypertension (n = 87; 93%), and/or diabetes (n = 50; 54%). Blood pressure, glucose control, and biochemical parameters improved in the vast majority of patients postoperatively. Infections were the most common complication. Most cases (n = 70, 88%) with reported long-term outcome survived to publication (median follow-up 6 months).

CONCLUSION

Ectopic ACTH- and/or CRH-secreting pheochromocytoma should be considered in patients presenting with ACTH-dependent Cushing syndrome and adrenal mass. Despite the challenge in diagnosis, patient outcomes appear favorable.

Etiology, baseline clinical profile and comorbidities of patients with Cushing's syndrome at a single endocrinological center

PURPOSE

The aim of this study was to compare phenotype of patients with pituitary, adrenal and ectopic CS and identify the differences regarding biochemical parameters, clinical presentations, and comorbidities in CS patients who were diagnosed at the single endocrinological center in Wroclaw.

METHODS

The study population involved 64 patients with CS (53 women and 11 men) diagnosed in Department of Endocrinology, Diabetes and Isotope Therapy in 2000-2018. Patients were divided into three etiologic groups: pituitary dependent-CS (P-CS) (64%), adrenal dependent CS (A-CS) (25%), and CS from an ectopic source (E-CS) (11%).

RESULTS

Percentage of men in the A-CS group was significantly higher than in the other etiologic groups. ACTH, UFC, and cortisol in DST were significantly higher in E-CS group compare to P-CS and A-CS (p < 0.05). Mean potassium level in E-CS group was significantly lower than in P-CS and A-CS (p < 0.05). Median of time elapsed to diagnosis was significantly lower in the E-CS group compared with either the P-CS and the A-CS group (p < 0.01). The most frequently symptoms in CS patients were skin alterations (82.8%), weight gain (81.2%), and hypertension (81.2%).

CONCLUSIONS

The epidemiology of CS is changing toward a growing proportion of A-CS. All patients with E-CS presented a profound hypokalemia. Salient hypokalemia could be a biochemical marker more suggestive for E-CS rather than P-CS. The incidence of diabetes is more frequent in E-CS group than in P-CS and A-CS groups.

The difference between steroid diabetes mellitus and type 2 diabetes mellitus: a whole-body 18F-FDG PET/CT study

AIMS

Steroid diabetes mellitus (SDM) is a metabolic syndrome caused by an increase in glucocorticoids, and its pathogenesis is unclear. ¹⁸F-FDG PET/CT can reflect the glucose metabolism of tissues and organs under living conditions. Here, PET/CT imaging of SDM and type 2 diabetes mellitus (T2DM) rats was used to visualize changes in glucose metabolism in the main glucose metabolizing organs and investigate the pathogenesis of SDM.

METHODS

SDM and T2DM rat models were established. During this time, PET/CT imaging was used to measure the %ID/g value of skeletal muscle and liver to evaluate glucose uptake. The pancreatic, skeletal muscle and liver were analyzed by immunohistochemistry.

RESULTS

SDM rats showed increased fasting blood glucose and insulin levels, hyperplasia of islet α and β cells, increased FDG uptake in skeletal muscle accompanied by an up-regulation of PI3Kp85α, IRS-1, and GLUT4, no significant changes in liver uptake, and that glycogen storage in the liver and skeletal muscle increased. T2DM rats showed atrophy of pancreatic islet β cells and decreased insulin levels, significantly reduced FDG uptake and glycogen storage in skeletal muscle and liver.

CONCLUSIONS

The pathogenesis of SDM is different from that of T2DM. The increased glucose metabolism of skeletal muscle may be related to the increased compensatory secretion of insulin. Glucocorticoids promote the proliferation of islet α cells and cause an increase in gluconeogenesis in the liver, which may cause increased blood glucose.

Glucose metabolism in Cushing's syndrome

PURPOSE OF REVIEW

Impairment of glucose metabolism is commonly encountered in Cushing's syndrome. It is the source of significant morbidity and mortality even after successful treatment of Cushing's. This review is to understand the recent advances in understanding the pathophysiology of diabetes mellitus from excess cortisol.

RECENT FINDINGS

In-vitro studies have led to significant advancement in understanding the molecular effects of cortisol on glucose metabolism. Some of these findings have been translated with human data. There is marked reduction in insulin action and glucose disposal with a concomitant, insufficient increase in insulin secretion. Cortisol has a varied effect on adipose tissue, with increased lipolysis in subcutaneous adipose tissue in the extremities, and increased lipogenesis in visceral and subcutaneous truncal adipose tissue.

SUMMARY

Cushing's syndrome results in marked impairment in insulin action and glucose disposal resulting in hyperglycemia. Further studies are required to understand the effect on incretin secretion and action, gastric emptying, and its varied effect on adipose tissue.

Cushing's syndrome: Overview of clinical presentation, diagnostic tools and complications

Cushing's syndrome (CS) is a severe condition that results from chronic exposure to elevated circulating cortisol levels; it is a rare but potentially life-threating condition, especially when not timely diagnosed and treated. Even though the diagnosis can be straightforward in florid cases due to their typical phenotype, milder forms can be missed. Despite the availability of different screening tests, the diagnosis remains challenging as none of the available tools proved to be fully accurate. Due to the ubiquitous effect of cortisol, it is easy understandable that its excess leads to a variety of systemic complications including hypertension, metabolic syndrome, bone damages and neurocognitive impairment. This article discusses clinical presentation of CS with an eye on the most frequent cortisol-related comorbidities and discuss the main pitfalls of first- and second-line tests in endogenous hypercortisolism diagnostic workup.

Circulating Irisin Levels as a Marker of Osteosarcopenic-Obesity in Cushing's Disease

PURPOSE

To evaluate circulating irisin levels in patients with active and controlled Cushing's disease (CD).

DESIGN

Forty-four patients with CD evaluated during the active phase and after 12 months of biochemical remission and 40 controls were recruited.

METHODS

Phenotypic, anthropometric, hormonal and metabolic parameters, including insulin sensitivity estimation by homeostatic model of insulin resistance, Matsuda index and oral disposition index and circulating irisin levels were evaluated.

RESULTS

Patients with active CD showed lower irisin levels compared to controls (p<0.001) and controlled CD (p<0.001). The independent variables significantly associated with irisin were waist circumference (WC) (p=0.025), body fat percentage (BF%) (p=0.009), PTH (p=0.007) and chair rising test (CRT) (p<0.001) in active CD and WC (p=0.013), BF% (p=0.014), PTH (p=0.038), CRT (p=0.029) and urinary-free cortisol (p<0.001) in controlled CD.

CONCLUSION

Circulating irisin levels tend to be lower in patients with active CD compared to those with controlled CD and controls. They are strongly associated with osteosarcopenia and central obesity in CD and therefore may be a possible marker of diagnosis.

Dual-release hydrocortisone vs conventional glucocorticoids in adrenal insufficiency

BACKGROUND

Dual-release hydrocortisone (DR-HC) improves metabolism in patients with adrenal insufficiency. The aims of this study were to compare the cardiovascular and metabolic effects of conventional glucocorticoids (GCs) vs. DR-HC and of high vs. low doses of GCs, after 48 months of observation.

METHODS

We selected 27 patients on hydrocortisone (mean dose 17.5 ± 4.2 mg/day) and 20 patients on cortisone acetate (mean dose 37.5 ± 12.1 mg/day) who maintained this treatment (group A) and 53 patients switched to DR-HC (mean dose 22 ± 4.8 mg/day) (group B). At baseline and after 48 months, clinical and metabolic parameters and Framingham Risk Score (FRS) were obtained.

RESULTS

After 48 months, patients in group A had a significant increase from baseline in BMI (P < 0.001), waist circumference (P = 0.001), systolic blood pressure (P = 0.001), LDL cholesterol (P = 0.018), HbA1c (P = 0.020) and FRS (P = 0.002). By contrast, patients in group B had a significant decrease in BMI (P = 0.002), waist circumference (P = 0.015), diastolic blood pressure (P = 0.031), total (P = 0.006) and LDL cholesterol (P = 0.005), HbA1c (P < 0.001) and FRS (P = 0.015) compared to baseline. No significant differences between high and low doses of both conventional GCs and DR-HC were observed.

CONCLUSIONS

DR-HC is associated with an improvement of metabolic parameters and cardiovascular risk compared to conventional GCs, which are associated with a worsening of these parameters, regardless of the dose used.

The medical treatment with pasireotide in Cushing's disease: an Italian multicentre experience based on "real-world evidence"

A phase III study has demonstrated that 6-month pasireotide treatment induced disease control with good safety in 15-26% of patients with Cushing's disease (CD). The aim of the current study was to evaluate the 6-month efficacy and safety of pasireotide treatment according to the real-world evidence. Thirty-two CD patients started pasireotide at the dose of 600 µg twice a day (bid) and with the chance of up-titration to 900 µg bid, or down-titration to 450 or 300 µg bid, on the basis of urinary cortisol (UC) levels or safety. Hormonal, clinical and metabolic parameters were measured at baseline and at 3-month and 6-month follow-up, whereas tumour size was evaluated at baseline and at 6-month follow-up. At baseline, 31 patients had very mild to moderate disease and 1 patient had very severe disease. Five (15.6%) patients discontinued treatment for adverse events; the remaining 27 patients (26 with very mild to moderate disease and 1 with very severe disease), reached 6-month follow-up. Considering the group of patients with very mild to moderate disease, responsiveness, defined by the normalization (<1 the upper limit of normal range, ULN) or near normalization (>1 and ≤1.1 ULN) of UC levels, was registered in 21 patients (full control in 19 and near control in 2), corresponding to 67.7% and 80.8% according to an "intention-to-treat" or "per-protocol" methodological approach, respectively. Weight, body mass index, waist circumference, as well as total and LDL-cholesterol significantly decreased, whereas fasting plasma glucose and glycated haemoglobin significantly increased. Hyperglycaemia was documented in 81.2%, whereas gastrointestinal disturbances in 40.6% of patients. In conclusion, in the real-life clinical practice, pasireotide treatment normalizes or nearly normalizes UC in at least 68% of patients with very mild to moderate disease, with consequent improvement in weight, visceral adiposity and lipid profile, despite the occurrence or deterioration of diabetes in the majority of cases, confirming the usefulness of this treatment in patients with milder disease and without uncontrolled diabetes.

Factors predicting long-term comorbidities in patients with Cushing's syndrome in remission

PURPOSE

In Cushing's syndrome, comorbidities often persist after remission of glucocorticoid excess. Here, we aim to identify factors predicting long-term comorbidities in patients with Cushing's syndrome in remission.

METHODS

In a retrospective cross-sectional study, 118 patients with Cushing's syndrome in remission (52 pituitary, 58 adrenal, 8 ectopic) were followed for a median of 7.9 years (range 2-38) after the last surgery. Associations between baseline anthropometric, metabolic, hormonal parameters at diagnosis, and comorbidities (obesity, diabetes, hyperlipidemia, hypertension, osteoporosis, depression) at last follow-up, were tested by uni- and multivariate regression analysis.

RESULTS

In patients with manifest comorbidities at diagnosis, remission of Cushing's syndrome resolved diabetes in 56% of cases, hypertension in 36% of cases, hyperlipidaemia in 23%, and depression in 52% of cases. In a multivariate regression analysis, age, fasting glucose, BMI, and the number of comorbidities at diagnosis were positive predictors of the number of long-term comorbidities, while baseline 24-h urinary free cortisol (UFC) negatively correlated with the persistence of long-term comorbidities. The negative relationship between baseline UFC and long-term comorbidities was also found when pituitary and adrenal Cushing's cases were analyzed separately. Baseline UFC was negatively related to the time of exposure to excess glucocorticoids.

CONCLUSIONS

Long-term comorbidities after remission of Cushing's syndrome depend not only on the presence of classic cardiovascular risk factors (age, hyperglycemia, BMI), but also on the extent of glucocorticoid excess. Lower baseline UFC is associated with a higher number of long-term comorbidities, possibly due to the longer exposure to excess glucocorticoids in milder Cushing's syndrome.

Changes in glucose metabolism based on 75-g oral glucose tolerance tests before and after surgery for adrenal Cushing's syndrome

Adrenal Cushing's syndrome (CS) is caused by cortisol-producing adrenal adenoma and is frequently accompanied by glucose metabolism disorders, which are characterized by increased insulin resistance and insufficient β-cell compensation. However, considering the rarity of CS, few studies have assessed whether the glucose metabolism disorders could be ameliorated by surgical treatment. In this case series, we evaluated glucose metabolism before and after surgery in 11 patients (10 women and 1 man) who underwent unilateral adrenalectomy for overt adrenal CS between 2005 and 2016. Patients with pre-diagnosed diabetes mellitus (DM) were excluded. Pre- and post-operative 75-g oral glucose tolerance tests were performed. Cortisol secretion decreased significantly after surgery (median 24-h urinary free cortisol: 582.0 μg/day [interquartile range: 321.0-743.0 μg/day] to 31.3 μg/day [23.6-40.6 μg/day], p = 0.001). The results of the OGTT generally improved after surgery (normal glucose tolerance/impaired glucose tolerance/DM: 2/8/1 to 8/3/0), with significant decreases in the immunoreactive insulin and glucose levels. We also found a decrease in the median homeostatic model assessment of insulin resistance (2.4 [1.4-2.8] to 1.0 [0.6-1.1], p = 0.002), and increases in the median Matsuda index (3.0 [2.3-4.5] to 8.2 [6.3-11.4], p < 0.001), median insulinogenic index (0.70 [0.22-1.51] to 1.22 [0.78-1.64], p = 0.08), and median disposition index (609.1 [237.8-1,095.2] to 1,286.0 [1,034.6-1,857.6], p = 0.002). These findings indicate that adrenalectomy for adrenal CS without overt DM may help ameliorate glucose metabolism disorders, and improve both insulin resistance and insulin secretion.

Insulin sensitivity and secretion and adipokine profile in patients with Cushing's disease treated with pasireotide

PURPOSE

To evaluate the effect of pasireotide on β-cell and adipose function in patients with Cushing's disease (CD).

METHODS

Clinical and hormonal parameters, insulin secretion evaluated by HOMA-β and by the area under the curve (AUC_2h) of C-peptide during a mixed meal tolerance test and insulin sensitivity, evaluated by the euglycaemic hyperinsulinaemic clamp, were evaluated in 12 patients with active CD, before and after 6 and 12 months of pasireotide. In addition, a panel of adipokines including leptin (Ob), leptin/leptin receptor ratio (Ob/Ob-R ratio), adiponectin, resistin, visfatin, adipocyte fatty acid binding protein (AFABP) and non-esterified fatty acids (NEFAs) was evaluated at baseline and after 12 months of pasireotide.

RESULTS

During 12 months of pasireotide treatment, a significant decrease in weight (p = 0.004), BMI (p = 0.008), waist circumference (p = 0.009), urinary free cortisol (p = 0.007), fasting insulinaemia (p = 0.007), HOMA-β (p = 0.015) and AUC_{2h c-peptide} (p = 0.017), concomitance with an increase in fasting glycaemia (p = 0.015) and HbA1c (p = 0.030), was found. With regard to adipokines, a significant decrease in Ob (p = 0.039), Ob/Ob-R ratio (p = 0.017) and AFABP (p = 0.036) was observed concomitant with a significant increase in Ob-R (p = 0.028) after 12 months of pasireotide.

CONCLUSIONS

12 months of treatment with pasireotide in CD is associated with an impairment of insulin secretion and an improvement of adipose function without any interference in insulin sensitivity.

Pasireotide treatment reduces cardiometabolic risk in Cushing's disease patients: an Italian, multicenter study

PURPOSE

Patients with Cushing's disease (CD) experience metabolic alterations leading to increased cardiovascular mortality. Recently, the visceral adiposity index (VAI) has been proposed as a marker of visceral adipose tissue dysfunction (ATD) and of the related cardiometabolic risk. We aimed to evaluate the impact of 12-month pasireotide treatment on cardiometabolic risk in CD patients.

METHODS

This is a multicentre, prospective, and observational study. Sixteen CD patients, referred to the Endocrine Units of the University Hospitals of Messina, Napoli, Padova, and Palermo (Italy), successfully treated with pasireotide for 12 month have been enrolled. In all patients, we assessed anthropometric, clinical, and biochemical parameters and calculated VAI, ATD severity, Framingham, and atherosclerotic cardiovascular disease (ASCVD) risk scores, before and after 6 and 12 months of treatment with pasireotide (1200-1800 mcg/daily).

RESULTS

Before starting pasireotide treatment, ATD was present in 7/16 patients (mild in 2/16, moderate in 3/16, and severe 2/16). After 12 months of treatment: (i) 24h-urinary free cortisol levels (p = 0.003), BMI (p < 0.001), waist circumference (p = 0.001), LDL-cholesterol (p = 0.033), total-cholesterol (p = 0.032), triglycerides (p = 0.030), VAI (p = 0.015), and ATD severity (p = 0.026) were significantly decreased as compared to baseline; (ii) ATD was present in only 1/16 patients; (iii) prevalence of diabetes mellitus (p = 0.015) and HbA1c levels (p = 0.001) were significantly increased as compared to baseline; (iv) Framingham and ASCVD risk scores were not significantly different from pre-treatment values.

CONCLUSIONS

Twelve-month pasireotide treatment significantly reduces VAI and ATD in CD patients. These positive effects on cardiometabolic risk occur despite no change in Framingham and ASCVD risk scores and the increase in the prevalence of diabetes mellitus.

Secondary Diabetes Mellitus in Patients with Endogenous Cushing’s Syndrome - Clinical Characteristics at Diagnosis

Background and aims. Endogenous Cushing’s syndrome is a rare disease associated with severe morbidity and increased mortality if untreated. Diabetes mellitus is a frequent initial complaint of these patients. Our aim was to investigate the clinical characteristics at the time of diagnosis in a cohort of patients with endogenous Cushing’s syndrome (CS).

Material and methods. A retrospective analysis of the presentation of 68 cases diagnosed with endogenous Cushing’s syndrome followed-up in our institution was performed.

Results: There were 57 women and 11 men, aged 18-74 years (mean 45.57±14.2). 38 had Cushing’s disease (CD) while 30 had adrenal CS. The most frequent signs/symptoms leading to the initial consultation and diagnostic suspicion were central obesity (55 cases, 80.88%), purple striae (28 cases, 41.1%), secondary arterial hypertension (27 cases, 39.7%), secondary diabetes mellitus (24 cases, 35.29%), hirsutism in 23/55 women (41.81%), hypogonadism in 23 cases (33.82%), proximal myopathy in 17 cases (25%), edema (10 cases, 14.7%). 13 cases (19.11%) also had secondary osteoporosis (diagnosed by dual energy x-ray absorptiometry - DXA osteodensitometry). Among the two diagnostic groups there were several differences. Proximal myopathy, secondary hypertension and diabetes mellitus were all more frequent in cases with adrenal Cushing compared to those with CD. (p= 0.011, 0.006 and 0.024, respectively). This did not reflect more severe hypercortisolism in adrenal CS, as the hormonal values were similar in the two groups.

Conclusion: If associated with certain clinical signs, some nonspecific (central obesity, edema, arterial hypertension), other more suggestive of CS (purple striae, proximal myopathy) diabetes mellitus could be the initial sign of this severe condition.

Diabetes Mellitus Secondary to Cushing's Disease

Associated with important comorbidities that significantly reduce patients' overall wellbeing and life expectancy, Cushing's disease (CD) is the most common cause of endogenous hypercortisolism. Glucocorticoid excess can lead to diabetes, and although its prevalence is probably underestimated, up to 50% of patients with CD have varying degrees of altered glucose metabolism. Fasting glycemia may nevertheless be normal in some patients in whom glucocorticoid excess leads primarily to higher postprandial glucose levels. An oral glucose tolerance test should thus be performed in all CD patients to identify glucose metabolism abnormalities. Since diabetes mellitus (DM) is a consequence of cortisol excess, treating CD also serves to alleviate impaired glucose metabolism. Although transsphenoidal pituitary surgery remains the first-line treatment for CD, it is not always effective and other treatment strategies may be necessary. This work examines the main features of DM secondary to CD and focuses on antidiabetic drugs and how cortisol-lowering medication affects glucose metabolism.

Glucose Metabolism Abnormalities in Cushing Syndrome: From Molecular Basis to Clinical Management

An impaired glucose metabolism, which often leads to the onset of diabetes mellitus (DM), is a common complication of chronic exposure to exogenous and endogenous glucocorticoid (GC) excess and plays an important part in contributing to morbidity and mortality in patients with Cushing syndrome (CS). This article reviews the pathogenesis, epidemiology, diagnosis, and management of changes in glucose metabolism associated with hypercortisolism, addressing both the pathophysiological aspects and the clinical and therapeutic implications. Chronic hypercortisolism may have pleiotropic effects on all major peripheral tissues governing glucose homeostasis. Adding further complexity, both genomic and nongenomic mechanisms are directly induced by GCs in a context-specific and cell-/organ-dependent manner. In this paper, the discussion focuses on established and potential pathologic molecular mechanisms that are induced by chronically excessive circulating levels of GCs and affect glucose homeostasis in various tissues. The management of patients with CS and DM includes treating their hyperglycemia and correcting their GC excess. The effects on glycemic control of various medical therapies for CS are reviewed in this paper. The association between DM and subclinical CS and the role of screening for CS in diabetic patients are also discussed.

The degree of urinary hypercortisolism is not correlated with the severity of cushing's syndrome

Cushing syndrome (CS) is characterized by increased morbidity and mortality compared to the general population. However, there are patients who have more clinical aggressive forms than others. Aim of the study is to evaluate whether the degree of hypercortisolism, defined by the number of times urinary free cortisol (UFC) levels exceed the upper limit of the normal range (ULN), is related to the worsening of phenotypic features, as well as metabolic and cardiovascular parameters, in a cohort of CS patients. A cross-sectional study was conducted on 192 patients with active CS, consecutively presenting at the outpatients' clinic of the University Hospitals of Ancona, Naples, and Palermo. Patients were grouped into mild (UFC not exceeding twice the ULN), moderate (2-5 times the ULN), and severe (more than 5 times the ULN) hypercortisolism. Thirty-seven patients (19.3 %) had mild, 115 (59.8 %) moderate, and 40 (20.9 %) severe hypercortisolism. A significant trend of increase among the three groups was demonstrated for 8-, 16-, and 24-h serum cortisol levels (p < 0.001) and serum cortisol after low dose of dexamethasone suppression test (p = 0.001). No significant trend of increase was found regarding phenotype and comorbidities. The degree of hypercortisolism by itself does not appear to be a sufficient parameter to express the severity of CS. Therefore, estimating the severity of CS according to biochemical parameters remains a challenge, while the clinical phenotype and the associated comorbidities might be more useful to assessing the severity of the CS.

Incompatibility between fasting and postprandial plasma glucose in patients with Cushing's syndrome

It is shown that glucocorticoids have discordant effects on plasma glucose concentration through their effects on hepatic glycogen deposition, gluconeogenesis and peripheral insulin resistance. Cushing's syndrome caused by cortisol overproduction is frequently accompanied with diabetes mellitus, but fasting plasma glucose (FPG) and post-glucose load plasma glucose levels are not examined in patients with Cushing's syndrome. The aim of this study was to investigate FPG, HbA1c and oral glucose tolerance test (OGTT) 2-h PG and their relationship in patients with Cushing's syndrome, in comparison with control subjects. Sixteen patients with Cushing's syndrome (ACTH-dependent 31%, ACTH-independent 69% and diabetes mellitus 50%) and 64 controls (32 patients with type 2 diabetes mellitus and 32 non-diabetic subjects matched for age, sex and BMI) were enrolled in this study. HbA1c and FPG in the patients with Cushing's syndrome were not different from the controls, whereas the FPG/HbA1c ratio was significantly lower in the patients with Cushing's syndrome than the controls. OGTT 2-h PG was significantly higher in the non-diabetic patients with Cushing's syndrome than the non-diabetic controls, while HbA1c was not different between both groups and FPG was significantly lower in the patients with Cushing's syndrome than the controls. HOMA-β but not HOMA-R was significantly higher in the patients with Cushing's syndrome than the controls. In conclusion, FPG was rather lower in the patients with Cushing's syndrome than the controls. Postprandial PG or post-glucose loaded PG, but not FPG, is useful to evaluate the abnormality of glucose metabolism in patients with Cushing's syndrome.

Complications of Cushing's syndrome: state of the art

Cushing's syndrome is a serious endocrine disease caused by chronic, autonomous, and excessive secretion of cortisol. The syndrome is associated with increased mortality and impaired quality of life because of the occurrence of comorbidities. These clinical complications include metabolic syndrome, consisting of systemic arterial hypertension, visceral obesity, impairment of glucose metabolism, and dyslipidaemia; musculoskeletal disorders, such as myopathy, osteoporosis, and skeletal fractures; neuropsychiatric disorders, such as impairment of cognitive function, depression, or mania; impairment of reproductive and sexual function; and dermatological manifestations, mainly represented by acne, hirsutism, and alopecia. Hypertension in patients with Cushing's syndrome has a multifactorial pathogenesis and contributes to the increased risk for myocardial infarction, cardiac failure, or stroke, which are the most common causes of death; risks of these outcomes are exacerbated by a prothrombotic diathesis and hypokalaemia. Neuropsychiatric disorders can be responsible for suicide. Immune disorders are common; immunosuppression during active disease causes susceptibility to infections, possibly complicated by sepsis, an important cause of death, whereas immune rebound after disease remission can exacerbate underlying autoimmune diseases. Prompt treatment of cortisol excess and specific treatments of comorbidities are crucial to prevent serious clinical complications and reduce the mortality associated with Cushing's syndrome.

cGMP and Brown Adipose Tissue

The second messenger cyclic guanosine monophosphate (cGMP) is a key mediator in physiological processes such as vascular tone, and its essential involvement in pathways regulating metabolism has been recognized in recent years. Here, we focus on the fundamental role of cGMP in brown adipose tissue (BAT) differentiation and function. In contrast to white adipose tissue (WAT), which stores energy in the form of lipids, BAT consumes energy stored in lipids to generate heat. This so-called non-shivering thermogenesis takes place in BAT mitochondria, which express the specific uncoupling protein 1 (UCP1). The energy combusting properties of BAT render it a promising target in antiobesity strategies in which BAT could burn the surplus energy that has accumulated in obese and overweight individuals. cGMP is generated by guanylyl cyclases upon activation by nitric oxide or natriuretic peptides. It affects several downstream molecules including cGMP-receptor proteins such as cGMP-dependent protein kinase and is degraded by phosphodiesterases. The cGMP pathway contains several signaling molecules that can increase cGMP signaling, resulting in activation and recruitment of brown adipocytes, and hence can enhance the energy combusting features of BAT. In this review we highlight recent results showing the physiological significance of cGMP signaling in BAT, as well as pharmacological options targeting cGMP signaling that bear a high potential to become BAT-centered therapies for the treatment of obesity.

The hypertension of Cushing's syndrome: controversies in the pathophysiology and focus on cardiovascular complications

Cushing's syndrome is associated with increased mortality, mainly due to cardiovascular complications, which are sustained by the common development of systemic arterial hypertension and metabolic syndrome, which partially persist after the disease remission. Cardiovascular diseases and hypertension associated with endogenous hypercortisolism reveal underexplored peculiarities. The use of exogenous corticosteroids also impacts on hypertension and cardiovascular system, especially after prolonged treatment. The mechanisms involved in the development of hypertension differ, whether glucocorticoid excess is acute or chronic, and the source endogenous or exogenous, introducing inconsistencies among published studies. The pleiotropic effects of glucocorticoids and the overlap of the several regulatory mechanisms controlling blood pressure suggest that a rigorous comparison of in-vivo and in-vitro studies is necessary to draw reliable conclusions. This review, developed during the first ‘Altogether to Beat Cushing's syndrome’ workshop held in Capri in 2012, evaluates the most important peculiarities of hypertension associated with CS, with a particular focus on its pathophysiology. A critical appraisal of most significant animal and human studies is compared with a systematic review of the few available clinical trials. A special attention is dedicated to the description of the clinical features and cardiovascular damage secondary to glucocorticoid excess. On the basis of the consensus reached during the workshop, a pathophysiology-oriented therapeutic algorithm has been developed and it could serve as a first attempt to rationalize the treatment of hypertension in Cushing's syndrome.

Italian Society for the Study of Diabetes (SID)/Italian Endocrinological Society (SIE) guidelines on the treatment of hyperglycemia in Cushing's syndrome and acromegaly

Hyperglycemia is a common feature associated with states of increased growth hormone secretion and glucocorticoid levels. The purpose of these guidelines is to assist clinicians and other health care providers to take evidence-based therapeutic decisions for the treatment of hyperglycemia in patients with growth hormone and corticosteroid excess. Both the SID and SIE appointed members to represent each society and to collaborate in Guidelines writing. Members were chosen for their specific knowledge in the field. Each member agreed to produce-and regularly update-conflicts of interest. The authors of these guidelines prepared their contributions following the recommendations for the development of Guidelines, using the standard classes of recommendation shown below. All members of the writing committee provided editing and systematic review of each part of the manuscript, and discussed the grading of evidence. Consensus was guided by a systematic review of all available trials and by interactive discussions.

Italian Society for the Study of Diabetes (SID)/Italian Endocrinological Society (SIE) guidelines on the treatment of hyperglycemia in Cushing's syndrome and acromegaly

BACKGROUND

Hyperglycemia is a common feature associated with states of increased growth hormone secretion and glucocorticoid levels.

AIMS

The purpose of these guidelines is to assist clinicians and other health care providers to take evidence-based therapeutic decisions for the treatment of hyperglycemia in patients with growth hormone and corticosteroid excess.

METHODOLOGY

Both the SID and SIE appointed members to represent each society and to collaborate in Guidelines writing. Members were chosen for their specific knowledge in the field. Each member agreed to produce--and regularly update--conflicts of interest. The Authors of these guidelines prepared their contributions following the recommendations for the development of Guidelines, using the standard classes of recommendation shown below. All members of the writing committee provided editing and systematic review of each part of the manuscript, and discussed the grading of evidence. Consensus was guided by a systematic review of all available trials and by interactive discussions.

Metabolic comorbidities in Cushing's syndrome

Cushing's syndrome (CS) patients have increased mortality primarily due to cardiovascular events induced by glucocorticoid (GC) excess-related severe metabolic changes. Glucose metabolism abnormalities are common in CS due to increased gluconeogenesis, disruption of insulin signalling with reduced glucose uptake and disposal of glucose and altered insulin secretion, consequent to the combination of GCs effects on liver, muscle, adipose tissue and pancreas. Dyslipidaemia is a frequent feature in CS as a result of GC-induced increased lipolysis, lipid mobilisation, liponeogenesis and adipogenesis. Protein metabolism is severely affected by GC excess via complex direct and indirect stimulation of protein breakdown and inhibition of protein synthesis, which can lead to muscle loss. CS patients show changes in body composition, with fat redistribution resulting in accumulation of central adipose tissue. Metabolic changes, altered adipokine release, GC-induced heart and vasculature abnormalities, hypertension and atherosclerosis contribute to the increased cardiovascular morbidity and mortality. In paediatric CS patients, the interplay between GC and the GH/IGF1 axis affects growth and body composition, while in adults it further contributes to the metabolic derangement. GC excess has a myriad of deleterious effects and here we attempt to summarise the metabolic comorbidities related to CS and their management in the perspective of reducing the cardiovascular risk and mortality overall.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's 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 Cushing's 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.

Clinical and biochemical manifestations of Cushing's

INTRODUCTION

Cushing's syndrome is associated with a number of clinical manifestations and co-morbidities which may not resolve even after long-term remission leading to excessive mortality.

MATERIALS AND METHODS

This review summarizes the main manifestations of Cushing's syndrome (active or in remission) with particular focus on data from recently published literature.

CONCLUSION

Obesity and metabolic alterations, hypertension and cardio/cerebrovascular complications, hypercoagulability/thromboembolism, neuropsychiatric, muscle/skeletal and immune consequences remain the most challenging. Cardiovascular consequences and immunosuppression determine the main causes of death in Cushing's syndrome necessitating early intervention when possible.

Comorbidities in Cushing's disease

INTRODUCTION

Cushing's disease is a rare disorder characterized by overproduction of ACTH from a pituitary adenoma leading to hypercortisolemia that in turn leads to increased morbidity and mortality.

METHODS

Here we review the comorbidities associated with Cushing's disease and their impact on quality of life and mortality.

RESULTS

Recent evidence suggests that correction of hypercortisolemia may not lead to complete resolution of comorbidities associated with this condition. In particular, increased cardiovascular risk may persist despite long-term remission of hypercortisolemia. This may be related to persistence of visceral adiposity, adverse adipokine profile, glucose intolerance, hypertension, dyslipidemia, atherosclerosis and a procoagulant phenotype. Prior prolonged exposure to glucocorticoids also may have irreversible effects on the central nervous system, leading to persistent cognitive and mood alterations. Osteoporosis and fractures, especially vertebral fractures, can further add to morbidity and a poor quality of life. Normalization of cortisol levels leads to significant improvement in comorbidities but long-term data regarding complete resolution are lacking and need further study.

CONCLUSION

Early diagnosis and treatment of hypercortisolemia, aggressive management of comorbidities along with long-term follow-up is crucial for the optimal recovery of these patients.

Gender-Specific Differences in Clinical Profile and Biochemical Parameters in Patients with Cushing's Disease: A Single Center Experience

Cushing's disease (CD) is remarkably prevalent among females; however, more severe clinical presentation and adverse outcomes have been found in males. The purpose of this study was to investigate the overall clinical profile and biochemical parameters in patients with CD to identify the gender differences. Here we describe our series of CD patients referred to our medical center during 2012-2013. Among 73 cases, females presented a marked preponderance compared to males. Males had significantly higher ACTH, BMI, HbA1c, systolic blood pressure, and hemoglobin than females. For the first time, the incidence of fatty liver and hepatic function was also shown to be elevated in males. Multiple linear regression analysis was performed to further investigate the correlation of risk factors with hypokalemia, HbA1c, and systolic blood pressure. Gender and serum cortisol were associated with hypokalemia. Age, gender, and serum cortisol were significantly associated with HbA1c. Additionally, only gender was significantly associated with systolic blood pressure. Regarding clinical presentation, purple striae seemed to occur more frequently in males than in females. Thus, more severe clinical presentation, biochemical parameters, and complications were found in males than in females. Clinical professionals should pay more attention to the diagnosis and management of males with CD.