Relationship between serum sialic acid and sialylated glycoproteins in alcoholics.

AIMS: Total sialic acid (TSA) has been suggested as a marker for chronic alcohol abuse. It seems that the elevation of TSA during excessive alcohol consumption reflects the changes in sialylated glycoproteins in the sera. On the other hand, chronic ethanol consumption increases the desialylation rate of many serum glycoproteins. The aim of this study was to evaluate the relationship between the total and free form of sialic acid levels (FSA), and the concentration of sialylated glycoproteins in alcoholics. METHODS: We determined the serum concentration of many glycoproteins (alpha1-antitrypsin, alpha1-acid glycoprotein, haptoglobin, ceruloplasmin, transferrin, complement C3 protein, fibrinogen and immunoglobulin G) in a sample of 100 alcoholics and 30 healthy controls. Total sialic acid was determined by the enzymatic method and its free form by using a modification of the thiobarbituric acid method. RESULTS: Among alcoholics, we found increased concentrations of alpha1-antitrypsin and alpha1-acid glycoprotein but decreased levels of transferrin. The concentrations of TSA and FSA were significantly higher in alcoholics than in healthy controls. The tested glycoproteins, except for transferrin and immunoglobulin G, positively correlated with TSA and FSA. The correlations with TSA were higher than that with FSA. CONCLUSIONS: Chronic alcohol abuse alters the concentrations of some sialylated glycoproteins in the sera. The alpha1-antitrypsin, alpha1-acid glycoprotein, and transferrin are the only affected glycoproteins. The serum level of total and free form of sialic acid in the sera of alcoholics depends on the concentration of the most sialylated glycoproteins.

Serum free sialic acid as a marker of alcohol abuse.

BACKGROUND: Previous studies have shown that serum total sialic acid (TSA) concentration significantly increases during alcohol abuse. Chronic ethanol consumption impairs glycosylation of many proteins. The increased desialylation rate of serum glycoproteins is one of the effects of alcohol abuse. The aim of this study was to investigate the diagnostic value of free sialic acid (FSA) as a marker of alcohol abuse. METHODS: We determined serum FSA concentrations in the group of 156 alcoholic subjects and 35 healthy control subjects by means of a modification of the thiobarbituric acid method. The alcoholic group was divided into subgroups according to their history of abuse. RESULTS: The FSA concentration was significantly higher in alcoholic subjects than in healthy controls. The subjects who consumed alcohol for longer than a week showed significantly higher FSA level than those who consumed alcohol for a shorter period. The serum FSA concentration was significantly higher in alcoholic subjects with elevated markers of liver dysfunction. The diagnostic accuracy of FSA was high, although it did not differ from TSA, and was limited by its low sensitivity. CONCLUSIONS: This study shows that FSA concentration in the sera of alcoholic subjects is increased. The low diagnostic sensitivity is accompanied by high specificity, however the accuracy is high and similar to the accuracy of TSA. Free sialic acid does not seem to be a better marker of alcohol abuse than TSA and current markers.

[New and traditional laboratory markers of alcohol abuse in hospitalized alcohol dependent men]. / Nowe i tradycyjne laboratoryjne wskazniki nadmiernego picia alkoholu u hospitalizowanych mezczyzn uzaleznionych od alkoholu.

AIM: Evaluation of the diagnostic value (sensitivity, specificity and accuracy) of the new-carbohydrate-deficient transferrin (CDT), sialic acid (SA) and traditional (GGT, AST, ALT and MCV) markers of alcohol abuse in alcohol dependent men irrespective of the time of abstinence. METHOD: 75 alcohol dependent men admitted for treatment have been tested. The examination was performed twice: upon admission to the hospital and after 3 weeks of hospitalization. CDT was estimated using an immunoturbidimetric assay after anion-exchange chromatography and sialic acid by the enzymatic colorimetric method. The diagnostic accuracy was calculated as the area under the ROC curve (AUC). RESULTS: At the time of admission to hospital, the values of CDT and sialic acid were elevated in comparison with the control group, similarly as with the traditional tests. After 3 weeks of hospitalization all test results decreased. CDT correlated positively with AST and sialic acid with ALT and GGT. The highest diagnostic accuracy was obtained for CDT (AUC=0.89). The diagnostic accuracy of sialic acid was lower than MCV, GGT and AST, but the same as ALT (AUC=0.66). CONCLUSIONS: CDT exhibits the highest diagnostic usefulness for alcohol abuse in alcohol dependent men in different time of abstinence. The tests with high diagnostic accuracy (CDT, MCV and GGT) are still useful after 3 weeks of hospitalization (abstinence), when the remaining tests are normalized.

The diagnostic accuracy of carbohydrate-deficient transferrin, sialic acid and commonly used markers of alcohol abuse during abstinence.

BACKGROUND: The normalization of alcohol abuse markers during the abstinence depends on the time since the last drinking. The aim of this study was to evaluate the diagnostic accuracy (area under the curve-AUC, sensitivity and specificity) of CDT, sialic acid and others biochemical and hematological markers of chronic alcohol abuse during abstinence. METHODS: We studied 75 patients admitted to the treatment of alcohol dependence. The blood samples were collected upon admission to the hospital. CDT was estimated using an immunoturbidimetric assay after anion-exchange chromatography and sialic acid by enzymatic colorimetric method. RESULTS: Mean values of all markers were significantly higher. All tests, except SA, negatively correlated with time of abstinence but not with age, duration of dependence and amounts of weekly alcohol consumption. The area under the curve (AUC) for all tested markers decreased progressively during the abstinence. The highest AUC was obtained for CDT (0.98) and the lowest for ALT (0.78) when alcohol was consumed in the last week. AUC for sialic acid was lower than of CDT but higher than of ALT. CONCLUSIONS: We conclude that the diagnostic accuracy for tested laboratory markers depends on the self-reported time of abstinence being the highest for CDT in the first week of abstinence. The accuracy of sialic acid was observed between GGT and ALT.