Relation of plasma carnitine and aminotransferases to alcohol dose and time of dependence.

BACKGROUND: Serum aspartate and alanine aminotransferases (AST, ALT) and plasma carnitine are all indirect biomarkers of alcohol abuse. Carnitine transfers long chain fatty acids from cytoplasm to mitochondria for β-oxidation. The aim of the study was determination the relationship between daily alcohol intake, time of alcohol dependence, plasma carnitine and serum aminotransferases.

PATIENTS AND METHODS: we studied 26 men addicted for 2-30 years, consuming ethanol 75-700 g/day (alcoholic group) and 17 healthy men (control group).

RESULTS: In alcoholics, compared to the controls, we found: a significant increase in serum: AST (p = 0.0014), ALT (p = 0.0071), AST/ALT ratio (p < 0.000); significantly lower plasma free carnitine (FC) (p = 0.0316) and total carnitine (TC) (p = 0.0349); a significant negative correlation between FC (r =-0.6200; R2 = 0.3844; p = 0.0007 ), TC (r = -0.4365; R2 = 0.1905; p = 0.0258) and time of alcohol dependence, suggesting carnitine as an indirect marker of alcohol abuse. We did not find any significant correlation between FC, TC and levels of alcohol or aminotransferase activity.

CONCLUSIONS: In the alcoholic group: an increase in serum activity of AST, ALT, AST/ALT ratio confirm liver injury; low plasma FC, TC may indicate on damage to mitochondrial β-oxidation caused by alcohol metabolites. The significantly higher plasma FC and TC in patients consuming the largest, compared to patients consuming smaller doses of alcohol, may be caused by: lowered carnitine demand of injured liver cells, decreased urinary carnitine excretion by impaired renal tubules, leakage carnitine to blood from damaged muscles by the higher amount of alcohol. The negative correlation between carnitine concentration and time of alcohol dependence may suggest the potential use of carnitine for treatment of alcohol abuse.