Relationship between serum sialic acid and sialylated glycoproteins in alcoholics.
OBJECTIVE
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.
Chrostek
Lech
L
Department of Biochemical Diagnostics, Medical University, Waszyngtona 15A, Bialystok, Poland. chrostek@amb.edu.pl
Cylwik
Bogdan
B
Krawiec
Agnieszka
A
Korcz
Walenty
W
Szmitkowski
Maciej
M
D000328:Adult; D000368:Aged; D000437:Alcoholism / Q000097:blood* / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019158:N-Acetylneuraminic Acid / Q000097:blood*; D009961:Orosomucoid / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism; D000515:alpha 1-Antitrypsin / Q000097:blood
D015415:Biomarkers; D006023:Glycoproteins; D009961:Orosomucoid; D014168:Transferrin; D000515:alpha 1-Antitrypsin; D019158:N-Acetylneuraminic Acid