Emerging role of circadian clock disruption in alcohol-induced liver disease.

The detrimental health effects of excessive alcohol consumption are well documented. Alcohol-induced liver disease (ALD) is the leading cause of death from chronic alcohol use. As with many diseases, the etiology of ALD is influenced by how the liver responds to other secondary insults. The molecular circadian clock is an intrinsic cellular timing system that helps organisms adapt and synchronize metabolism to changes in their environment. The clock also influences how tissues respond to toxic, environmental, and metabolic stressors, like alcohol. Consistent with the essential role for clocks in maintaining health, genetic and environmental disruption of the circadian clock contributes to disease. While a large amount of rich literature is available showing that alcohol disrupts circadian-driven behaviors and that circadian clock disruption increases alcohol drinking and preference, very little is known about the role circadian clocks play in alcohol-induced tissue injuries. In this review, recent studies examining the effect alcohol has on the circadian clock in peripheral tissues (liver and intestine) and the impact circadian clock disruption has on development of ALD are presented. This review also highlights some of the rhythmic metabolic processes in the liver that are disrupted by alcohol and potential mechanisms through which alcohol disrupts the liver clock. Improved understanding of the mechanistic links between the circadian clock and alcohol will hopefully lead to the development of new therapeutic approaches for treating ALD and other alcohol-related organ pathologies.