Relationship between Serum Gamma-Glutamyltransferase and Glutathione Antioxidant System in Patients with Liver Cirrhosis of Various Etiology

Oxidative stress involvement in liver diseases has been extensively studied. A direct assessment of the reactive species incriminated is avoided due to their short lifespan and high cost. For these reasons an inexpensive and easy to perform test for whole body oxidative stress is highly desired. This pilot study was conducted to assess the relationship between γ-glutamyl transferase (GGT) activity and markers of oxidative stress: reduced glutathione (GSH), glutathione peroxidase (GPx) activity and lipid peroxidation in patients with liver cirrhosis due to chronic ethanol consumption and viral hepatitis. Forty-eight patients with alcoholic liver cirrhosis and cirrhosis developed after HBV and HCV infection were included in this study.Blood GSH andGPxand serum GGT and MDAwere assayed and the results were statistically analyzed. The activity of serum GGT was significantly higher in the alcoholic group. The relationship between GGT activity, GSH and MDA levels was different between groups.A strong significant positive correlation between GGT and GSH was noticed for the patients from GGT Q3 and Q4 quartiles in the group of viral liver cirrhosis, while for alcoholics the relationship between GGT and GSH showed the trend for a negative correlation.The values of serum MDA differ significantly between groups (p<0.015); a very significant variation was observed at low levels of GGT activity (p<0.006). Our study demonstrates that the GSH antioxidant defense system is more compromisedin alcoholic cirrhosisand tends to correlate negatively with GGT. Even in its normal range GGT might be an early and sensitive marker of oxidative stress.