Circadian Rhythm and Sleep Disruption: Causes, Metabolic Consequences and Countermeasures.

Circadian (∼ 24 hour) timing systems pervade all kingdoms of life, and temporally optimize behaviour and physiology in humans. Relatively recent changes to our environments, such as the introduction of artificial lighting, can disorganize the circadian system, from the level of the molecular clocks that regulate the timing of cellular activities to the level of synchronization between our daily cycles of behaviour and the solar day. Sleep/wake cycles are intertwined with the circadian system, and global trends indicate that these too are increasingly subject to disruption. A large proportion of the world's population is at increased risk of environmentally-driven circadian rhythm and sleep disruption, and a minority of individuals are also genetically predisposed to circadian misalignment and sleep disorders. The consequences of disruption to the circadian system and sleep are profound and include myriad metabolic ramifications, some of which may be compounded by adverse effects on dietary choices. If not addressed, the deleterious effects of such disruption will continue to cause widespread health problems; therefore, implementation of the numerous behavioural and pharmaceutical interventions that can help restore circadian system alignment and enhance sleep will be important

Appetite-regulating hormones from the upper gut: disrupted control of xenin and ghrelin in night workers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)ObjectiveShift work is associated with circadian rhythm disorder, impaired sleep and behavioural changes, including eating habits, predisposing to obesity and metabolic dysfunctions. It involves a neuro-hormonal dysregulation of appetite towards positive energy balance, including increased ghrelin and decreased leptin, but little is known about other hormones, such as xenin, derived from the upper gut (like ghrelin), and lower gut hormones. Our objective was to compare night workers with day workers in relation to appetite-regulating hormones and other metabolic parameters. DesignCross-sectional, observational study. ParticipantsTwenty-four overweight women, divided into night shift workers (n=12) and day shift workers (n=12). MeasurementsBMI, waist circumference, fat mass percentage; diet composition; Pittsburgh Sleep Quality Index; lipids; adipokines; meal tolerance test curves of glucose, insulin, ghrelin, PYY3-36, oxyntomodulin, xenin, GLP-1; insulin sensitivity (Stumvoll index). ResultsNight workers, as compared with day workers, had greater body fat mass percentage and tendency to greater waist circumference despite similar BMI; greater energy intake; impaired sleep; lower insulin sensitivity; increased triglycerides and tendency to increased C-reactive protein; similar levels of leptin and other adipokines. Night workers had a blunted post-meal suppression of ghrelin (AUCi(0-60min) 19<bold>41399</bold> vs -141<bold>9</bold>+/- 9<bold>0</bold>ng/ml<bold>60</bold>min, P<0<bold>01</bold>); blunted rise of xenin (AUC(0-180min) 8690<bold>9</bold>+/- 2988<bold>2</bold> vs 28504<bold>4</bold>+/- 20308<bold>3</bold>pg/ml<bold>180</bold>min, P<0<bold>01</bold>) and similar curves of PYY3-36, oxyntomodulin and GPL-1. ConclusionCompared with day workers within the same BMI range, night workers presented a disrupted control of ghrelin and xenin, associated with behavioural changes in diet and sleep and increased adiposity and related metabolic alterations.796807811Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Evaluation of serum xenin and ghrelin levels and their relationship with nonalcoholic fatty liver disease and insulin resistance in obese adolescents

Aim Xenin is a peptide of the neurotensin/xenopsin/xenin family secreted from gastric cells and other tissues. The first aim of this study was to investigate the serum xenin and ghrelin levels in obese children and compare the patients with healthy controls. The second aim was to compare the xenin levels in patients with nonalcoholic fatty liver disease (NAFLD) and also with insulin resistance with the patients without these complications