[P2-49] Urinary Secretion of Oxidative Stress Markers and Melatonin in Patients with Severe Motor and Intellectual Disabilities
[Introduction] Patients with severe motor and intellectual disabilities (SMID) are associated with sleep disorders and disturbed thermoregulation, in addition to respiratory disorder. Melatonin is involved in the regulation of circadian rhythms, and also actions as a free radical scavenger and antioxidant. Here we aimed to examine urinary secretion of oxidative stress markers and melatonin in SMID patients, in order to investigate a potential role of these factors in the pathogenesis of SMID. [Methods] Subjects were composed of 24 SMID patients aged from 21 to 58 years, and age-matched 25 healthy controls. Urine samples were collected at 6:00 am. We performed enzyme-linked immunosorbent assay for oxidative stress markers, 8-hydroxy-2’-deoxyguanosine (8-OHdG), hexanoyl-lysine adduct (HEL), total antioxidant power (TAO) and a main metabolite of melatonin, 6-sulfatoxymelatonin (6-SM) using a commercial kit. Stat Flex v6 was used for statistical analysis. Ethical committee in Tokyo Metropolitan Fuchu Medical Center for the Disabled approved the study, and informed consents were provided by patients’ families and controls.
[Results] The means of urinary 8-OHdG, HEL and 6-SM in SMID were higher than those in controls. There were no significant differences in the urinary levels of TAO between them. The respiratory disturbances and sleep problems were significantly correlated with the means of 8-OHdG and 6-SM. There were no correlations between the levels of 6-SM and oxidative stress markers. [Conclusions] Interestingly, urinary secretion of melatonin was increased in SMID patients in spite of the presence of sleep problems, irrespective of changes in oxidative stress markers.
[Results] The means of urinary 8-OHdG, HEL and 6-SM in SMID were higher than those in controls. There were no significant differences in the urinary levels of TAO between them. The respiratory disturbances and sleep problems were significantly correlated with the means of 8-OHdG and 6-SM. There were no correlations between the levels of 6-SM and oxidative stress markers. [Conclusions] Interestingly, urinary secretion of melatonin was increased in SMID patients in spite of the presence of sleep problems, irrespective of changes in oxidative stress markers.