Analyses of melatonin, cytokines, and sleep in chronic renal failure.
PURPOSE
Inflammation and oxidative stress are involved in the process of chronic renal failure (CRF). CRF patients show indication of sleep disturbances, and the melatonin rhythm, which modulates sleep, is abnormal in these patients; however, it is still unclear whether inflammation could be related to the blockage of melatonin production and sleep disturbances in this population. The aim of this study was to characterize and correlate sleep, the melatonin rhythm, and the levels of the inflammatory cytokines tumor necrosis factor (TNF) and interleukin (IL)-6 in patients with CRF and controls.


METHODS
Sleep was evaluated by the "Sleep Quality Index Pittsburgh" (PSQI) questionnaire, and melatonin and cytokine contents in saliva and blood samples, respectively, were analyzed by ELISA.


RESULTS
The CRF group scored higher on the global PSQI, which indicates a lower sleep quality and a higher prevalence of sleep disorders, than the control group. The CRF individuals also showed lower melatonin content than the control groups, both during the day and at night, and lacked rhythmicity in melatonin production. The CRF group also showed higher contents of TNF and IL-6 than the control group and a negative correlation between TNF and melatonin content.


CONCLUSION
These results suggest that the sleep disorders observed in the CRF group were probably related to the low production of melatonin observed in this population. The high level of TNF, as previously demonstrated in other pathologies, is probably involved in this blockage of melatonin production in CRF.
['Pinto|Aline Rodrigues|AR|', 'da Silva|Nathani Cristina|NC|', 'Pinato|Luciana|L|']
D000328:Adult D000368:Aged D002940:Circadian Rhythm D016207:Cytokines D005260:Female D006801:Humans D015850:Interleukin-6 D007676:Kidney Failure, Chronic D008297:Male D008550:Melatonin D008875:Middle Aged D018384:Oxidative Stress D012463:Saliva D012893:Sleep Wake Disorders D014409:Tumor Necrosis Factor-alpha
Inflammation Sleep quality Behavior Biological rhythms Immune-pineal axis