Epigenetics of Sleep Disorders: An Emerging Field in Diagnosis and Therapeutics

The complex web of obesity: from genetics to precision medicine

INTRODUCTION

Obesity is a growing public health concern affecting both children and adults. Since it involves both genetic and environmental components, the management of obesity requires both, an understanding of the underlying genetics and changes in lifestyle. The knowledge of obesity genetics will enable the possibility of precision medicine in anti-obesity medications.

AREAS COVERED

Here, we explore health complications and the prevalence of obesity. We discuss disruptions in energy balance as a symptom of obesity, examining evolutionary theories, its multi-factorial origins, and heritability. Additionally, we discuss monogenic and polygenic obesity, the converging biological pathways, potential pharmacogenomics applications, and existing anti-obesity medications - specifically focussing on the leptin-melanocortin and incretin pathways. Comparisons between childhood and adult obesity genetics are made, along with insights into structural variants, epigenetic changes, and environmental influences on epigenetic signatures.

EXPERT OPINION

With recent advancements in anti-obesity drugs, genetic studies pinpoint new targets and allow for repurposing existing drugs. This creates opportunities for genotype-informed treatment options. Also, lifestyle interventions can help in the prevention and treatment of obesity by altering the epigenetic signatures. The comparison of genetic architecture in adults and children revealed a significant overlap. However, more robust studies with diverse ethnic representation is required in childhood obesity.

[Research Progress in the Effect of Exercise Intervention on Sleep Disorders and the Mechanisms Involved]

Sleep disorders, a common concern in modern society, seriously affect people's physical and mental health. Reported findings suggest that both acute exercise intervention and long-term regular exercise intervention can improve the disrupted sleep structure and normalize the duration and proportion of the different phases of sleep. Moreover, exercise intervention has a positive effect on the endocrine functions, the metabolic functions, the immune response, the autonomic nervous system, and cardiac functions during sleep. It is a non-medicative therapeutic strategy for improving sleep disorders. The specific type of exercise intervention (aerobic exercise, resistance exercise, or meditative movement) adopted is one of the moderating variables of exercise intervention programs. Different types of exercise improve sleep disorders by way of different mechanisms. Exercise volume and intensity are another moderating variable of exercise intervention programs. The optimal amount and intensity of exercise for different individuals to improve sleep disorders may vary. Exercise interventions implemented at the different times throughout a day can also have varying degrees of impact on sleep disorders and there is no consensus on the optimal exercise time for improving sleep quality at present. Herein, we summarized the mechanisms by which exercise intervention improves sleep disorders from four perspectives, including epigenetics, hyperarousal, human circadian rhythm, and body temperature regulation. In addition, we discussed the current gaps and prospects of research in this field, aiming to provide a theoretical basis for the development of exercise prescriptions for sleep disorders.

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

Insomnia is a stress-related sleep disorder conceptualised within a diathesis-stress framework, which it is thought to result from predisposing factors interacting with precipitating stressful events that trigger the development of insomnia. Among predisposing factors genetics and epigenetics may play a role. A systematic review of the current evidence for the genetic and epigenetic basis of insomnia was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. A total of 24 studies were collected for twins and family heritability, 55 for genome-wide association studies, 26 about candidate genes for insomnia, and eight for epigenetics. Data showed that insomnia is a complex polygenic stress-related disorder, and it is likely to be caused by a synergy of genetic and environmental factors, with stress-related sleep reactivity being the important trait. Even if few studies have been conducted to date on insomnia, epigenetics may be the framework to understand long-lasting consequences of the interaction between genetic and environmental factors and effects of stress on the brain in insomnia. Interestingly, polygenic risk for insomnia has been causally linked to different mental and medical disorders. Probably, by treating insomnia it would be possible to intervene on the effect of stress on the brain and prevent some medical and mental conditions.

An Overview of Epigenetics in Obesity: The Role of Lifestyle and Therapeutic Interventions

Obesity has become a global epidemic that has a negative impact on population health and the economy of nations. Genetic predispositions have been demonstrated to have a substantial role in the unbalanced energy metabolism seen in obesity. However, these genetic variations cannot entirely explain the massive growth in obesity over the last few decades. Accumulating evidence suggests that modern lifestyle characteristics such as the intake of energy-dense foods, adopting sedentary behavior, or exposure to environmental factors such as industrial endocrine disruptors all contribute to the rising obesity epidemic. Recent advances in the study of DNA and its alterations have considerably increased our understanding of the function of epigenetics in regulating energy metabolism and expenditure in obesity and metabolic diseases. These epigenetic modifications influence how DNA is transcribed without altering its sequence. They are dynamic, reflecting the interplay between the body and its surroundings. Notably, these epigenetic changes are reversible, making them appealing targets for therapeutic and corrective interventions. In this review, I discuss how these epigenetic modifications contribute to the disordered energy metabolism in obesity and to what degree lifestyle and weight reduction strategies and pharmacological drugs can restore energy balance by restoring normal epigenetic profiles.