Circadian disruption and sleep disorders in neurodegeneration

Disruptions of circadian rhythms and sleep cycles are common among neurodegenerative diseases and can occur at multiple levels.Accumulating evidence reveals a bidirectional relationship between disruptions of circadian rhythms and sleep cycles and neurodegenerative diseases.Circadian disruption and sleep disorders aggravate neurodegeneration and neurodegenerative diseases can in turn disrupt circadian rhythms and sleep.Importantly,circadian disruption and various sleep disorders can increase the risk of neurodegenerative diseases.Thus,harnessing the circadian biology findings from preclinical and translational research in neurodegenerative diseases is of importance for reducing risk of neurodegeneration and improving symptoms and quality of life of individuals with neurodegenerative disorders via approaches that normalize circadian in the context of precision medicine.In this review,we discuss the implications of circadian disruption and sleep disorders in neurodegenerative diseases by summarizing evidence from both human and animal studies,focusing on the bidirectional links of sleep and circadian rhythms with prevalent forms of neurodegeneration.These findings provide valuable insights into the pathogenesis of neurodegenerative diseases and suggest a promising role of circadian-based interventions.

Light therapy:a new option for neurodegenerative diseases

Given the increasing incidence of neurodegenerative disease(ND),recent research efforts have intensified the search for curative treatments.Despite significant research,however,existing therapeutic options for ND can only slow down the progression of the disease,but not provide a cure.Light therapy(LT)has been used to treat some mental and sleep disorders.This review illustrates recent studies of the use of LT in patients with ND and highlights its potential for clinical applications.The literature was collected from PubMed through June 2020.Selected studies were primarily English articles or articles that could be obtained with English abstracts and Chinese main text.Articles were not limited by type.Additional potential publications were also identified from the bibliographies of identified articles and the authors’reference libraries.The identified literature suggests that LT is a safe and convenient physical method of treatment.It may alleviate sleep disorders,depression,cognitive function,and other clinical symptoms.However,some studies have reported limited or no effects.Therefore,LT represents an attractive therapeutic approach for further investigation in ND.LT is an effective physical form of therapy and a new direction for research into treatments for ND.However,it requires further animal experiments to elucidate mechanisms of action and large,double-blind,randomized,and controlled trials to explore true efficacy in patients with ND.