Cortisol circadian rhythm and jet-lag syndrome: evaluation of salivary cortisol rhythm in a group of eastward travelers

Novel agents to treat adrenal insufficiency: findings of preclinical and early clinical trials

INTRODUCTION

Adrenal insufficiency currently affects over 300/million population, with higher morbidity and mortality compared to the general population. Current glucocorticoid replacement therapy is limited by a lack of reliable biomarkers to guide dosing, inter-patient variation in metabolism and narrow therapeutic window. Increased morbidity and mortality may relate to unappreciated under- or over-exposure to glucocorticoids and impaired cortisol circadian rhythm. New agents are required to emulate physiological cortisol secretion and individualize glucocorticoid dosing.

AREAS COVERED

History of glucocorticoid therapy, current limitations, and novel chronotherapeutic glucocorticoid delivery mechanisms. Literature search incorporated searches of PubMed and Embase utilizing terms such as adrenal insufficiency, Chronocort, Plenadren, continuous subcutaneous hydrocortisone infusion (CHSI), and glucocorticoid receptor modulator.

EXPERT OPINION

Glucocorticoid chronotherapy is necessary to optimize glucocorticoid exposure and minimize complications. Current oral chronotherapeutics provide improved dosing functionality, but are modifiable only in specific increments and cannot accommodate ultradian cortisol variation. Current data show improvement in quality of life but not morbidity or mortality outcomes. CHSI has significant potential for individualized glucocorticoid dosing, but would require a suitable biomarker of glucocorticoid adequacy to be implementable. Avenues for future research include determining a glucocorticoid sufficiency biomarker, development of interstitial or systemic cortisol monitoring, or development of glucocorticoid receptor modulators.

Molecular Derangements and the Diagnosis of ACTH-Dependent Cushing's Syndrome

Endogenous Cushing's syndrome (CS) is associated with morbidities (diabetes, hypertension, clotting disorders) and shortens life because of infections, pulmonary thromboembolism, and cardiovascular disease. Its clinical presentation is immensely variable, and diagnosis and treatment are often delayed. Thus, there are many opportunities for basic and clinical research leading to better tests, faster diagnosis, and optimized medical treatments. This review focuses on CS caused by excessive adrenocorticotropin (ACTH) production. It describes current concepts of the regulation of ACTH synthesis and secretion by normal corticotropes and mechanisms by which dysregulation occurs in corticotrope (termed "Cushing's disease") and noncorticotrope (so-called ectopic) ACTH-producing tumors. ACTH causes adrenal gland synthesis and pulsatile release of cortisol; the excess ACTH in these forms of CS leads to the hypercortisolism of endogenous CS. Again, the differences between healthy individuals and those with CS are highlighted. The clinical presentations and their use in the interpretation of CS screening tests are described. The tests used for screening and differential diagnosis of CS are presented, along with their relationship to cortisol dynamics, pathophysiology, and negative glucocorticoid feedback regulation in the two forms of ACTH-dependent CS. Finally, several gaps in current understanding are highlighted in the hope of stimulating additional research into this challenging disorder.

Exposure to dim light at night alters daily rhythms of glucose and lipid metabolism in rats

Nocturnal light pollution has been rapidly increasing during the last decades and even though dim artificial light at night (ALAN) has been associated with metabolic diseases, its mechanism is still far from clear. Therefore, the aim of our study was to thoroughly analyze the effects of ALAN on energy metabolism, metabolites, metabolic hormones, and gene expression. Male Wistar rats were kept in either the standard light:dark (12:12) cycle or exposed to ALAN (∼2 lx) during the whole 12-h dark phase for 2 weeks. Energy metabolism was measured in metabolic cages. In addition, we measured plasma and hepatic metabolites, clock and metabolic gene expression in the liver and epididymal adipose tissue, and plasma hormone levels. In ALAN rats, we observed an unexpected transitory daytime peak of locomotor activity and a suppression of the peak in locomotor activity at the beginning of the dark period. These changes were mirrored in the respiratory exchange ratio. Plasma metabolites became arrhythmic, and plasma and hepatic cholesterol levels were increased. Lost rhythmicity of metabolites was associated with disrupted behavioral rhythms and expression of metabolic genes. In the liver, the rhythms of metabolic sensors were either phase-advanced (Ppara, Pgc1a, Nampt) or arrhythmic (Sirt1, Lxra) after ALAN. The rhythmic pattern of Ppara and Sirt1 was abolished in the adipose tissue. In the liver, the amplitude of the daily rhythm in glycogen content was attenuated, the Glut2 rhythm was phase-advanced and Foxo1 lost its daily rhythmicity. Moreover, hepatic Foxo1 and Gck were up-regulated after ALAN. Interestingly, several parameters of lipid metabolism gained rhythmicity (adiponectin, Hmgcs2, Lpl, Srebf1c) in the liver, whereas Noct became arrhythmic in the adipose tissue. Peripheral clock genes maintained their robust oscillations with small shifts in their acrophases. Our data show that even a low level of ALAN can induce changes in the daily pattern of behavior and energy metabolism, and disturb daily rhythms of genes encoding key metabolic sensors and components of metabolic pathways in the liver and adipose tissue. Disturbed metabolic rhythms by ALAN could represent a serious risk factor for the development and progression of metabolic diseases.

Genetic Basis of ACTH-Secreting Adenomas

Cushing's disease represents 60-70% of all cases of Cushing's syndrome, presenting with a constellation of clinical features associated with sustained hypercortisolism. Molecular alterations in corticotrope cells lead to the formation of ACTH-secreting adenomas, with subsequent excessive production of endogenous glucocorticoids. In the last few years, many authors have contributed to analyzing the etiopathogenesis and pathophysiology of corticotrope adenomas, which still need to be fully clarified. New molecular modifications such as somatic mutations of USP8 and other genes have been identified, and several case series and case reports have been published, highlighting new molecular alterations that need to be explored. To investigate the current knowledge of the genetics of ACTH-secreting adenomas, we performed a bibliographic search of the recent scientific literature to identify all pertinent articles. This review presents the most recent updates on somatic and germline mutations underlying Cushing's disease. The prognostic implications of these mutations, in terms of clinical outcomes and therapeutic scenarios, are still debated. Further research is needed to define the clinical features associated with the different genotypes and potential pharmacological targets.

[Medications when travelling with underlying inflammatory rheumatic disease]

Travelling poses particular challenges for patients with rheumatic diseases. This article provides specific guidance on how best to manage medication while away from home. Besides outlining advice on basic logistic issues, such as the transportation, importation and storage of drugs, the article concentrates on travelling while receiving immunosuppressive therapy and carrying narcotics. Especially when transporting narcotics, travel requires careful planning in advance in close collaboration with physicians on account of the strict and internationally diverse import restrictions on controlled substances. While travelling, all drugs should be kept in the original packaging, including the package insert and stored in carry-on luggage. A specific medical passport may be needed. Immunosuppressive and narcotic drugs require medical certificates issued by the prescribing physician, which may need to be certified by the responsible national agencies. Patients receiving glucocorticoid treatment who travel in or across multiple time zones should also be aware of how the medication impacts and interacts with circadian rhythms so as to optimize the anti-inflammatory effects of the drugs and to avoid unnecessary complications. Given the significant discrepancies in medical care and availability of medication worldwide, the article further stresses the importance of a comprehensive medical kit tailored to the patient's individual medicinal needs. Finally, as immunocompromised travellers are at increased risk of infections, advice is given on the use of anti-infective drugs and chemoprophylaxis for patients travelling to areas in which malaria is endemic as well as on their possible interactions with immunosuppressive treatment.