Coagulation protein function VII - Diametric effects of acetaldehyde on factor VII and factor IX function

The first metabolite of ethanol, acetaldehyde, has the ability to form addu cts with proteins and alter their function. It has been shown that acetalde hyde reacts with various proteins of the blood coagulation pathway and, sub sequently, produces a prolongation of the clotting time. This study evaluat ed the function of clotting proteins from the extrinsic coagulation pathway (factor VII) and the intrinsic coagulation pathway (factor IX) when preinc ubated with acetaldehyde as compared to a control and compared to preincuba tion with ethanol. Prior to use in a clotting assay, incubation times with acetaldehyde, ethanol, and the control were the same for both factors VII a nd IX. An automatic fibrometer measured the clotting times, Factor VII prei ncubated with acetaldehyde prolonged the clotting time. However, factor IX preincubated with acetaldehyde actually decreased the clotting time. Of int erest, both factors VII and IX preincubated with acetaldehyde produced stat istically significant results when compared to the control and ethanol. Thi s experiment indicates that acetaldehyde, in forming an adduct with protein s of the blood coagulation pathway, may induce a conformational change of f actors VII and IX so as to either increase or decrease the clotting time. T herefore, it is possible that some of the deranged coagulation in alcohol a busers may be a final net result of the interaction of acetaldehyde and pro teins of the coagulation pathway.