Circadian rhythm disruption and endocrine-related tumors

This review delved into the intricate relationship between circadian clocks and physiological processes,emphasizing their critical role in maintaining homeo-stasis.Orchestrated by interlocked clock genes,the circadian timekeeping system regulates fundamental processes like the sleep-wake cycle,energy metabolism,immune function,and cell proliferation.The central oscillator in the hypothalamic suprachiasmatic nucleus synchronizes with light-dark cycles,while peripheral tissue clocks are influenced by cues such as feeding times.Circadian disruption,linked to modern lifestyle factors like night shift work,correlates with adverse health outcomes,including metabolic syndrome,cardiovascular diseases,infec-tions,and cancer.We explored the molecular mechanisms of circadian clock genes and their impact on metabolic disorders and cancer pathogenesis.Specific associ-ations between circadian disruption and endocrine tumors,spanning breast,ovarian,testicular,prostate,thyroid,pituitary,and adrenal gland cancers,are highlighted.Shift work is associated with increased breast cancer risk,with PER genes influencing tumor progression and drug resistance.CLOCK gene expression correlates with cisplatin resistance in ovarian cancer,while factors like aging and intermittent fasting affect prostate cancer.Our review underscored the intricate interplay between circadian rhythms and cancer,involving the regulation of the cell cycle,DNA repair,metabolism,immune function,and the tumor microenvir-onment.We advocated for integrating biological timing into clinical consider-ations for personalized healthcare,proposing that understanding these connec-tions could lead to novel therapeutic approaches.Evidence supports circadian rhythm-focused therapies,particularly chronotherapy,for treating endocrine tumors.Our review called for further research to uncover detailed connections between circadian clocks and cancer,providing essential insights for targeted treatments.We emphasized the importance of public health interventions to mitigate lifestyle-related circadian disruptions and underscored the critical role of circadian rhythms in disease mechanisms and therapeutic interventions.

Bright artificial light at night is associated with increased body mass,poor reproductive success and compromised disease tolerance in Australian budgerigars(Melopsittacus undulatus)

Artificial light at night(ALAN)can cause circadian disruption and result in adverse behavioral and ecologi­cal effects in free-living birds,but studies on captive pet birds as companion animals have been infrequent.We studied the effects of exposure to bright ALAN on body mass,melatonin sulfate levels,reproduction and dis­ease severity in Australian budgerigars(Melopsittacus undulatus)kept in captivity.During the experiment,birds were kept under outdoor temperature,humidity and natural photoperiod from September to December.A total of 48 birds were equally split into 4 groups(6 mating pairs each)and concurrently exposed to ALAN of 200 lux with different duration(0,30,60 and 90 min).Monthly observations were recorded for all dependent parame­ters.ALAN exposure increased mass gain and suppressed melatonin levels in a dose-dependent manner,espe­cially during December.In addition,ALAN exposure in all duration groups decreased egg production and re­duced hatchability from 61%±14%in the ALAN-unexposed control group to 0%in the ALAN-exposed birds.Disease severity was also found to increase in line with the duration of ALAN exposure.In captive M.undu­latus,ALAN exposure was demonstrated to affect photoperiodic regulation with subsequent excess mass gain and reproduction impairment,and increased susceptibility to infections plausibly through duration dose-depen­dent suppression of melatonin.To the best of our knowledge,this is the first study to demonstrate a possible as­sociation between acute bright ALAN of increasing duration and both natural development of infections as well as reproductive cessation in captive birds.Our findings could be used to improve breeding conditions of captive birds.