Why only a few severe alcoholics develop liver disease, scientists now have a possible explanation.
In their new study, a research team from Northwestern University and Rush University Medical Center has shown that disrupted sleep and circadian rhythms can push those vulnerable over the edge to disease.
The team studied mice that essentially were experiencing what shift workers or people with jet lag suffer: their internal clocks were out of sync with the natural light-dark cycle.
Another group of mice had circadian disruption due to a faulty gene. Both groups were fed a diet without alcohol and next with alcohol, and the team then examined the physiological effects.
The researchers found the combination of circadian rhythm disruption and alcohol is a destructive double hit that can lead to alcoholic liver disease.
"Circadian disruption appears to be a previously unrecognized risk factor underlying the susceptibility to or development of alcoholic liver disease," said Fred W. Turek, the Charles E. and Emma H. Morrison Professor of Biology at Northwestern's Weinberg College of Arts and Sciences and one of the senior authors of the paper.
The two investigators and their groups first studied the effect of circadian rhythm disruption in an animal model of colitis and noted that disruption of sleep and circadian rhythms (caused by modeling shift work and chronic jet lag in the animals) caused more severe colitis in mice.
The study was published last month by the journal Plos One.