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Chronic heavy alcohol use is known to cause gut leakiness and alcoholic liver disease (ALD), but only 30% of heavy drinkers develop increased intestinal permeability and ALD. The hypothesis of this study was that disruption of circadian rhythms is a potential risk factor in actively drinking alcoholics for gut leakiness and endotoxemia. We studied 20 subjects with alcohol use disorder (AD) and 17 healthy controls (HC, 6 day workers, 11 night workers). Subjects wore a wrist actiwatch for 7 days and underwent a 24-h dim light phase assessment and urine collection for intestinal permeability. The AD group had significantly less total sleep time and increased fragmentation of sleep ( P < 0.05). AD also had significantly lower plasma melatonin levels compared with the HC [mean area under the curve (AUC) 322.78 ± 228.21 vs. 568.75 ± 304.26 pg/ml, P = 0.03]. In the AD group, AUC of melatonin was inversely correlated with small bowel and colonic intestinal permeability (lactulose-to-mannitol ratio, r = −0.39, P = 0.03; urinary sucralose, r = −0.47, P = 0.01). Cosinor analysis of lipopolysaccharide-binding protein (marker of endotoxemia) and lipopolysaccharide every 4 h for 24 h in HC and AD subjects had a midline estimating statistic of rhythm of 5,026.15 ± 409.56 vs. 6,818.02 ± 628.78 ng/ml ( P < 0.01) and 0.09 ± 0.03 vs. 0.15 ± 0.19 EU/ml ( P < 0.05), respectively. We found plasma melatonin was significantly lower in the AD group, and lower melatonin levels correlated with increased intestinal permeability and a marker of endotoxemia. Our study suggests the suppression of melatonin in AD may promote gut leakiness and endotoxemia.

Background: Alterations in the sleep -wake cycle leads to decreased melatonin secretion and it may be associated with sleep disorders and cancer risk. Exposure of light at night and rotating night shift decrease the melatonin production due to acute suppression of pineal melatonin secretion during night work has been suggested to increases cancer risks. Aims & Objectives: The objectives of the present study were to investigate the effect of light exposure at night on circadian pattern of 6-Sulfatoxy melatonin levels in night shift nursing professionals. Material and Methods: 62 healthy nursing professionals of both genders performing day and night shifts (continuous 9 days night shift with alternate day shifts) were recruited. Urine samples were collected at around 8 hour intervals (afternoon sample: between 13:00 to 15:00, night samples between 22:00 to 01:00 and morning samples between 05:00 to 08:00) while they were performing night duties and repeated when they were assigned day duties. Night melatonin level was decreased as compared to morning melatonin. Results: Night melatonin level was found declined as compared to morning level and this pattern was significant when compared night melatonin between night (16.71 ± 11.98) vs day shift (22.71 ± 13.25) and morning melatonin level between night (20.07 ± 14.13) vs day shifts (28.26 ± 14.14) (p