Specific electrocardiographic features associated with Cushing's disease

Relacorilant, a Selective Glucocorticoid Receptor Modulator in Development for the Treatment of Patients With Cushing Syndrome, Does Not Cause Prolongation of the Cardiac QT Interval

OBJECTIVE

To assess the effect of relacorilant, a selective glucocorticoid receptor modulator under investigation for the treatment of patients with endogenous hypercortisolism (Cushing syndrome [CS]), on the heart rate-corrected QT interval (QTc).

METHODS

Three clinical studies of relacorilant were included: (1) a first-in-human, randomized, placebo-controlled, ascending-dose (up to 500 mg of relacorilant) study in healthy volunteers; (2) a phase 1 placebo- and positive-controlled thorough QTc (TQT) study of 400 and 800 mg of relacorilant in healthy volunteers; and (3) a phase 2, open-label study of up to 400 mg of relacorilant administered daily for up to 16 weeks in patients with CS. Electrocardiogram recordings were taken, and QTc change from baseline (ΔQTc) was calculated. The association of plasma relacorilant concentration with the effect on QTc in healthy volunteers was assessed using linear mixed-effects modeling.

RESULTS

Across all studies, no notable changes in the electrocardiogram parameters were observed. At all time points and with all doses of relacorilant, including supratherapeutic doses, ΔQTc was small, generally negative, and, in the placebo-controlled studies, similar to placebo. In the TQT study, placebo-corrected ΔQTc with relacorilant was small and negative, whereas placebo-corrected ΔQTc with moxifloxacin positive control showed rapid QTc prolongation. These results constituted a negative TQT study. The model-estimated slopes of the concentration-QTc relationship were slightly negative, excluding an association of relacorilant with prolonged QTc.

CONCLUSION

At all doses studied, relacorilant consistently demonstrated a lack of QTc prolongation in healthy volunteers and patients with CS, including in the TQT study. Ongoing phase 3 studies will help further establish the overall benefit-risk profile of relacorilant.

Rationale and design of the cardiovascular status in patients with endogenous cortisol excess study (CV-CORT-EX): a prospective non-interventional follow-up study

BACKGROUND

Endogenous Cushing's syndrome (CS) results in increased cardiovascular (CV) morbidity and mortality. So far, most studies focussed on distinct disease entities rather than the integrity of the CV system. We here describe the design of the Cardiovascular Status in Endogenous Cortisol Excess Study (CV-CORT-EX), a study aiming to comprehensively investigate the health status of patients with endogenous CS (with a particular focus on CV phenotypes, biochemical aspects, quality of life, and psychosocial status).

METHOD

A prospective non-interventional cohort study performed at a German tertiary referral centre. At the time of enrolment, patients will be categorised as: (1) newly diagnosed overt CS, (2) recurrent overt CS, (3) CS in remission, (4) presence of mild autonomous cortisol excess (MACE). The target cohorts will be n = 40 (groups 1 + 2), n = 80 (group 3), and n = 20 (group 4). Patients with overt CS at the time of enrolment will be followed for 12 months after remission (with re-evaluations after 6 and 12 months). At each visit, patients will undergo transthoracic echocardiography, cardiac magnetic resonance imaging, 24-h electrocardiogram, 24-h blood pressure measurement, and indirect evaluation of endothelial function. Furthermore, a standardised clinical investigation, an extensive biochemical workup, and a detailed assessment of quality of life and psychosocial status will be applied. Study results (e.g. cardiac morphology and function according to transthoracic echocardiography and cardiac magnetic resonance imaging; e.g. prevalence of CV risk factors) from patients with CS will be compared with matched controls without CS derived from two German population-based studies.

DISCUSSION

CV-CORT-EX is designed to provide a comprehensive overview of the health status of patients with endogenous CS, mainly focussing on CV aspects, and the holistic changes following remission.

TRAIL REGISTRATION

ClinicalTrials.gov ( https://clinicaltrials.gov/ ) NCT03880513, registration date: 19 March 2019 (retrospectively registered). Protocol Date: 28 March 2014, Version 2.

Empagliflozin improves chronic hypercortisolism-induced abnormal myocardial structure and cardiac function in mice

Background:

Chronic exposure to excess glucocorticoids is frequently associated with a specific cardiomyopathy. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, has beneficial effects as it aids in the reduction of heart failure and cardiovascular mortality in hospitalized patients. The aim of this study was to investigate the effects of empagliflozin on chronic hypercortisolism-induced myocardial fibrosis and myocardial dysfunction in mice.

Methods:

Male C57BL/6J mice (6 weeks old) were randomized to control, corticosterone (CORT), and empagliflozin + CORT groups. After 4 weeks of administration, heart structure and function were evaluated by echocardiography, and peripheral blood and tissue samples were collected. Expressions of Ccl2, Itgax, Mrc1, and Adgre1 mRNA in heart tissue were evaluated by RT-PCR, and signal transducer and activator of transcription 3 (STAT3) and Toll-like receptor 4 (TLR4) protein expression were analyzed by Western blotting.

Results:

Empagliflozin effectively reduced body weight, liver triglyceride, visceral adipose volume, and uric acid in CORT-treated mice. Left ventricular hypertrophy and cardiac dysfunction were improved significantly, phosphorylated STAT3 and TLR4 were alleviated, and macrophage infiltration in the myocardium was inhibited after administration of empagliflozin in CORT-treated mice.

Conclusion:

Empagliflozin has beneficial effects on specific cardiomyopathy associated with CORT, and the results provide new evidence that empagliflozin might be a potential drug for the prevention of this disease.

The acute effects of hydrocortisone on cardiac electrocardiography, action potentials, intracellular calcium, and contraction: The role of protein kinase C

Hydrocortisone exerts adverse effects on various organs, including the heart. This study investigated the still unclear effects of hydrocortisone on electrophysiological and biochemical aspects of cardiac excitation-contraction coupling. In guinea pigs' hearts, hydrocortisone administration reduced the QT interval of ECG and the action potential duration (APD). In guinea pig ventricular myocytes, hydrocortisone reduced contraction and Ca²⁺ transient amplitudes. These reductions and the effects on APD were prevented by pretreatment with the protein kinase C (PKC) inhibitor staurosporine. In an overexpression system of Xenopus oocytes, hydrocortisone increased hERG K⁺ currents and reduced Kv1.5 K⁺ currents; these effects were negated by pretreatment with staurosporine. Western blot analysis revealed dose- and time-dependent changes in PKCα/βII, PKCε, and PKCγ phosphorylation by hydrocortisone in guinea pig ventricular myocytes. Therefore, hydrocortisone can acutely affect cardiac excitation-contraction coupling, including ion channel activity, APD, ECG, Ca²⁺ transients, and contraction, possibly via biochemical changes in PKC.

Morbidity of Cushing's Syndrome and Impact of Treatment

Cortisol excess in Cushing's syndrome is associated with metabolic, cardiovascular, and cognitive alterations, only partially reversible after resolution of hypercortisolism. Elevated cardiovascular risk may persist after eucortisolism has been achieved. Fractures and low bone mineral density are also described in Cushing's syndrome in remission. Hypercortisolism may induce irreversible structural and functional changes in the brain, leading to neuropsychiatric disorders in the active phase of the disease, which persist. Sustained deterioration of the cardiovascular system, bone remodeling, and cognitive function along with neuropsychological impairment are associated with high morbidity and poor quality of life before and after remission.

The risks of overlooking the diagnosis of secreting pituitary adenomas

Secreting pituitary adenomas that cause acromegaly and Cushing’s disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing tumours. The rarity of these conditions means that their diagnosis is not familiar to most non-specialist physicians. Consequently, pituitary adenomas may be overlooked and remain untreated, and affected individuals may develop serious comorbidities that reduce their quality of life and life expectancy. Because many signs and symptoms of pituitary adenomas overlap with those of other, more common disorders, general practitioners and non-endocrinology specialists need to be aware of the “red flags” suggestive of these conditions. A long duration of active disease in patients with secreting pituitary adenomas is associated with an increased risk of comorbidities and reduced quality of life. Appropriate treatment can lead to disease remission, and, although some symptoms may persist in some patients, treatment usually reduces the incidence and severity of comorbidities and improves quality of life. Therefore, correct, early diagnosis and characterization of a pituitary adenoma is crucial for patients, to trigger timely, appropriate treatment and to optimize outcome. This article provides an overview of the epidemiology of hormonal syndromes associated with pituitary adenomas, discusses the difficulties of and considerations for their diagnosis, and reviews the comorbidities that may develop, but can be prevented, by accurate diagnosis and appropriate treatment. We hope this review will help general practitioners and non-endocrinology specialists to suspect secreting pituitary adenomas and refer patients to an endocrinologist for confirmation of the diagnosis and treatment.

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.

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.

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.

[Cushing syndrome: When to suspect and how to confirm?]

Cushing's syndrome includes all the clinical manifestations induced by chronic glucocorticoid excess. The endogenous Cushing's syndrome is rare, but its prevalence, although difficult to define, is much higher in populations at risk. Data suggest that early and effective management would reduce morbidity and mortality after correction of hypercortisolism. It is not recommended to widespread test for Cushing's syndrome but targeted screening is indicated especially in the following indications: facio-troncular obesity, hypercatabolism signs, pituitary and adrenal tumor. In case of potential but less specific manifestation of Cushing's syndrome (diabetes, hypertension, osteoporosis, hypogonadism…), but unusual for age, familial background, or severity, particular attention will be paid to the clinical examination to search for signs of modest hypercortisolism which may justify screening. The positive diagnosis of Cushing's syndrome is based on two stages approach with the first tests simple and sensitive, and the second tests more specific, with investigations to determine the cause following a positive diagnosis.

Effects of Subcutaneous Pasireotide on Cardiac Repolarization in Healthy Volunteers: a Single‐Center, Phase I, Randomized, Four‐Way Crossover Study

The aim of this study was to evaluate the effects of subcutaneous pasireotide on cardiac repolarization in healthy volunteers. Healthy volunteers were randomized to one of four treatment sequences (n = 112) involving four successive treatments in different order: pasireotide 600 µg (therapeutic dose) or 1,950 µg (maximum tolerated dose) bid by subcutaneous injection (sc), placebo injection and oral moxifloxacin. Maximum ΔΔQTcI occurred 2 hours post-dose for both doses of pasireotide. Mean ΔΔQTcI was 13.2 milliseconds (90% CI: 11.4, 15.0) and 16.1 milliseconds (90% CI: 14.3, 17.9) for the 600 and 1,950 µg bid doses, respectively. Maximal placebo-subtracted change in QTcI from baseline for moxifloxacin was 11.1 (90% CI: 9.3, 12.9) milliseconds. Both pasireotide doses caused a reduction in heart rate: maximal heart rate change compared with placebo occurred at 1 hour for pasireotide 600 µg bid and at 0.5 hours for pasireotide 1,950 µg bid, with heart rate reductions of 10.4 and 14.9 bpm, respectively. At the therapeutic dose of 600 µg, pasireotide has a modest QT-prolonging effect. The relatively small increase of ∼3 milliseconds in ΔΔQTcI in the presence of a 3.25-fold increase in dose suggests a relatively flat dose–effect relationship of pasireotide on ΔΔQTcI in healthy volunteers. No safety concerns for pasireotide were identified during the study.