Determination of plasma α-glutathione-S-transferases in chronic alcohol abusers: Relationship with alcohol intake and liver involvement

Abstract

α-Gluthathione-S-transferases (α-GSTs) are enzymes involved in the cellular detoxifying processes; elevated circulating α-GSTs activity is considered to be an early index of liver damage. Glutathione (GSH)is the substrate for α-GST action. The aims of our study were: (1) to evaluate plasma GSH levels and α-GST activity in chronic alcohol abusers with or without liver cirrhosis; (2) to define the relationship between these two biochemical parameters; (3) to establish their clinical relevance in patients with alcohol abuse and/or liver damage. We studied 69 subjects (18 healthy subjects and 51 chronic alcohol abusers: 29 without liver cirrhosis and 22 with). Plasma α-GST activity was determined on baseline samples and every following day for a total of 10 days in five alcoholics by HEPKIT (Alpha-Biotech, Bionin International, Dublin, Ireland). GSH was determined on all subjects' baseline samples by fluorescent high-performance liquid chromatography. Alcohol intake was evaluated in all patients by determining blood-alcohol concentrations. Significant increases in plasma α-GSTs were observed in 9/29 (31%) alcoholics and 3/22 (13.6%) cirrhotics irrespective of their alcohol intake. GSH was significantly lower than normal values (P < 0.001) in all alcoholics with or without cirrhosis (controls 10.4 ± 4.8; alcoholics without cirrhosis 3.9 ± 1.4; alcoholics with cirrhosis 3.3 ± 1.6). No correlation was observed between plasma α-GST and GSH levels. Our data indicate that: (1) α-GST activity does not correlate with GSH levels in the plasma; (2) α-GSTs do not have clinical relevance as markers of recent alcohol intake; (3) in cirrhotics, α-GST does not provide more information than other liver function tests. However, plasma α-GST determination may be useful in selecting a subgroup of alcoholics in whom routine biochemical markers of liver damage are within reference ranges.