Platelet monoamine oxidase B activity as a state marker for alcolism: Trend over time during withdrawal and influence of smoking and gender

Abstract

Aims and methods: The present study evaluated time-related changes in platelet monoamine oxidase B (MAO-B) activity in an Italian cohort of alcohol-dependent subjects (n = 98) during early abstinence, and the effect of potential confounding factors, such as gender and smoking status, on the temporal trend of the enzyme activity. Results: While still under the influence of ethanol (time point T1), the mean value of platelet MAO-B activity in alcoholics was 6.4 ± 3.1 nmol/mg of protein/h. This increased by >40% (to 9.3 ± 4.4 nmol/mg of protein/h) after 8 days of withdrawal (T2), and remained stable thereafter (T3 and T4: 15 and 22 days of abstinence, respectively). In a cohort of 138 healthy subjects, MAO activity levels averaged 9.9 ± 0.9 nmol/mg of protein/h. In the group of alcoholic patients, alcohol intake cessation was confirmed by the progressive decrease of serum % carbohydrate-deficient transferrin (CDT), which was pathologically above the reference limits (6%) at T1 (7.8 ± 3.3%), declined to 6.6 ± 2.1% at T2 and reached physiological values at T3 and T4. In a subgroup of cirrhotic alcoholics, %CDT did not decrease over time, while MAO activity rose after the first week of abstinence, without further change at T3 and T4. During early withdrawal, neither gender nor tobacco smoking affected the temporal pattern of MAO activity. Conclusions: MAO-B can be regarded as a state marker of alcohol consumption. The temporal pattern of platelet MAO-B activity may be used for the diagnostic assessment of alcoholism and early abstinence, regardless of gender and smoking status.