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Vinyl chloride (VC) is a ubiquitous environmental contaminant for which human risk is incompletely understood. We have previously reported that high occupational exposure to VC directly caused liver damage in humans. However, whether VC may also potentiate liver injury from other causes is not known. C57Bl/6J mice were administered chloroethanol (CE), a major metabolite of VC, and lipopolysaccharide (LPS) 24 h after CE. Samples were harvested for determination of liver damage, inflammation, and changes in carbohydrate and lipid metabolism. In mice, CE exposure alone caused no detectable liver damage. LPS exposure caused inflammatory liver damage, oxidative stress, lipid accumulation, and glycogen depletion; the effect of all of these variables was potentiated by CE pre-exposure. In vitro experiments suggest that VC metabolite chloroacetaldehyde (CAA) directly damages mitochondria, which may explain the sensitization effect observed in vivo Moreover, co-exposure of cells to CAA and TNFα caused increased cell death, supporting the hypothesis of sensitization by VC metabolites. Taken together, these data demonstrate that exposure to VC/metabolites at levels that are not overtly hepatotoxic can potentiate liver injury caused by another hepatotoxicant. This serves as proof-of-concept that VC hepatotoxicity may be modified by an additional metabolic stress such as endotoxemia, which commonly occurs in acute (eg, sepsis) and chronic (eg, NAFLD) diseases., (© The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background Interactions between the liver, the gut, and the immune system are critical components of alcoholic liver disease (ALD). The aim of this study was to explore the associations between alcohol-induced liver injury, endotoxemia, and inflammation at admission and over time during abstinence, as well as to examine the sex-related differences in these parameters in alcohol-dependent individuals admitted to an alcohol treatment program. Methods A cohort of 48 otherwise healthy participants with alcohol use disorder, but no clinical signs of alcoholic liver injury (34 males [M]/14 females [F]) admitted to an alcohol detoxification program, was stratified into 2 groups based on baseline plasma alanine aminotransferase (ALT) levels (as a marker of liver injury). Group 1 (ALT < 40 U/l, 7M/8F) and Group 2 (ALT ≥ 40 U/l, 27M/6F) were identified. Plasma biomarkers of liver damage, endotoxemia, and inflammation were examined at baseline, day 8, and day 15 of the admission. The drinking history was also evaluated. Results Sixty-nine percent of patients had elevated ALT and other markers of liver damage, including aspartate aminotransferase and cytokeratin 18 (CK18 M65 and CK M30) at baseline, indicating the presence of mild ALD. Elevated CK18 M65:M30 ratio suggested a greater contribution of necrotic rather than apoptotic hepatocyte cell death in the liver injury observed in these individuals. Females showed greater elevations of liver injury markers compared to males, although they had fewer drinks per day and shorter lifetime duration of heavy drinking. Liver injury was associated with systemic inflammation, specifically, elevated plasma tumor necrosis factor-alpha levels. Compared to patients without liver injury, patients with mild ALD had greater endotoxemia (increased serum lipopolysaccharide levels), which decreased with abstinence and this decrease preceded the drop in CK18 M65 levels. Conclusions The study documented the association of mild alcohol-induced liver injury and endotoxemia, which improved with 2 weeks of abstinence, in a subset of individuals admitted to an alcohol detoxification program. [ABSTRACT FROM AUTHOR]