New Insights in Cushing Disease Treatment With Focus on a Derivative of Vitamin A

Dual effects of 9-cis retinoic acid on ACTH-dependent hyperplastic adrenal tissues

Retinoids play a pivotal role in adrenal development and differentiation. Recent clinical trials revealed therapeutic potential of both all-trans and 9-cis retinoic acid in patients with cortisol excess due to a pituitary ACTH-secreting adenoma and indicated that retinoids might act also on the adrenal. Aim of the present study was to evaluate the effect of 9-cis retinoic acid on adrenals from patients with ACTH-dependent Cushing’s syndrome. Adrenal specimens from six patients with Cushing’s disease were incubated with 10 nM–1 µM 9-cis retinoic acid with and without 10 nM ACTH. Cortisol secretion was measured by immunoassay and expression of genes involved in steroidogenesis as well as retinoic acid action were evaluated by real-time RT-PCR. Incubation with 10–100 nM 9-cis retinoic acid increased spontaneous cortisol secretion and expression of STAR and CYP17A. On the other hand, in wells treated with ACTH, 9-cis retinoic acid markedly diminished ACTH receptor upregulation and no stimulatory effect on cortisol secretion or steroidogenic enzyme synthesis was observed. ACTH itself increased ligand-induced retinoic acid receptor expression, possibly enhancing sensitivity to retinoic acid. Our findings indicate that the effect of 9-cis retinoic acid in presence of ACTH is distinct from unchallenged wells and support the hypothesis of a direct adrenal action in patients with Cushing’s disease.

Vitamin A failed to ameliorate clinical signs in dogs with pituitary-dependent hypercortisolaemia

BACKGROUND

In dogs with pituitary-dependent hypercortisolaemia, retinoic acid was shown to lower cortisol, reduce pituitary tumour size and decrease clinical signs when administered for six months. Oral vitamin A (retinol) has been used to treat various canine dermatoses in which retinoic acid has been efficacious.

OBJECTIVES

To determine if orally administered vitamin A lowers cortisol and reduces clinical signs in dogs with pituitary-dependent hypercortisolaemia over a five month period.

METHODS AND MATERIALS

Five dogs were enrolled in this study. Diagnosis of hypercortisolaemia was based on the presence of at least three clinical signs and one abnormal screening test. Diagnosis of pituitary-dependent disease was based on low dose dexamethasone suppression (LDDS) test results and symmetrical adrenal glands on ultrasound. Adrenocorticotropic hormone (ACTH) stimulation testing and adrenal ultrasound were performed at each visit. Plasma was collected at each visit and stored at -80°C for batch analysis of endogenous ACTH at conclusion of the study.

RESULTS

Four dogs completed the study. A fifth dog died from complications of hypercortisolaemia before the third month. One dog showed improvement in clinical signs, yet there was no significant decrease in adrenal gland size or cortisol concentrations. Endogenous ACTH concentrations at the fifth month were decreased from baseline in two dogs and increased from baseline in one dog. The treatment had no adverse effects.

CONCLUSIONS AND CLINICAL IMPORTANCE

Results from this study failed to show an improvement in clinical signs or cortisol concentration after five months of oral daily vitamin A in dogs with hypercortisolaemia.

Management of patients with persistent or recurrent Cushing's disease after initial pituitary surgery

INTRODUCTION

Treatment options for persistent and recurrent Cushing's disease (CD) include an individualized approach for repeat surgery, medical treatment, radiation therapy (RT), and bilateral adrenalectomy (BLA).

AREAS COVERED

In this expert opinion perspective, the authors review the latest treatment(s) for persistent/recurrent CD. A PubMed search was undertaken (English articles through May 2020) and relevant articles discussed. Repeat pituitary surgery should be considered in most patients with proven hypercortisolism; there is potential for cure with low risk of major complications. Medical therapy is valuable either alone, while awaiting the effects of RT, or in preparation for BLA. Medical therapy includes steroidogenesis inhibitors, agents that act at the pituitary or glucocorticoid receptor level, and novel agents in development. Radiation therapy has been used successfully to treat CD, but hypopituitarism risk and delayed efficacy (improved with radiosurgery) are major drawbacks. Laparoscopic BLA is safe and effective in patients with severe, difficult-to-manage hypercortisolism, but long-term follow-up is required as corticotroph tumor progression can develop.

EXPERT OPINION

Treatment of persistent/recurrent CD is challenging. Most patients require >1 therapy to achieve long-lasting remission. There is currently no ideal single treatment option that provides high and rapid efficacy, low adverse effects, and preserves normal pituitary-adrenal axis function.

Medical Management of Cushing's Syndrome: Current and Emerging Treatments

Endogenous Cushing's syndrome is a chronic disease associated with increased morbidity and mortality if not appropriately treated. Recurrence and/or persistence of hypercortisolemia after surgical treatment, especially for Cushing's disease, are high, and long-term medical treatment is used to decrease cortisol levels and risk of metabolic comorbidities. Medical treatment is also often required while waiting for radiation effects to take place. In some cases, severe or life-threatening hypercortisolism must be urgently and medically treated, via intravenous medications or with combination therapy, before patients can undergo surgery. In the last decade, medical treatment has progressed from a few steroidogenesis inhibitors to three novel drug groups: new inhibitors for steroidogenic enzymes with possibly fewer side effects, pituitary-directed drugs that aim to inhibit the pathophysiological pathways of Cushing's disease, and glucocorticoid receptor antagonists that block cortisol's action. Understanding the pathophysiology of Cushing's syndrome has also led to the identification of potential targets that may decrease adrenocorticotrophic hormone and/or cortisol excess, and/or decrease tumor cell proliferation, and induce senescence or apoptosis. We provide here a review of current and near-future medical options to treat Cushing's syndrome, and discuss updates on clinical trials and the efficacy and safety of novel or in-development drugs, as well as future potential targets.

Treatment challenges in pediatric Cushing's disease: Review of the literature with particular emphasis on predictive factors for the disease recurrence

Cushing's disease (CD) is a rare endocrine condition caused by a corticotroph pituitary tumor that produces adrenocorticotropic hormone. The current state of knowledge of CD treatment is presented in this article including factors that can be helpful in predicting remission and/or recurrence of the disease. The primary goals in CD treatment are quick diagnosis and effective, prompt treatment as the persistent disease is associated with increased morbidity and mortality. Cooperation of a team consisting of experienced pediatrician/adult endocrinologist, neuroradiologist, transsphenoidal neurosurgeon and (if necessary) radiotherapist contribute to the best treatment effects.