The effect of acetaldehyde-glycosaminoglycan mixtures upon Factor IXa and Factor IX-Deficient Plasma

Earlier studies have shown that acetaldehyde, the primary intermediate in the biological degradation of ethanol, interacts with enzymes and zymogens of the common coagulation pathway, prolonging prothrombin time and activated partial thromboplastin time (APTT), and that acetaldehyde-glycosaminoglycans (GAGs) mixtures synergistically prolong clotting times (Brecher, A. S. (2005). In Comprehensive Handbook of Alcohol Related Pathology. Vol. 3(93), pp. 1223-1244). In this study, the effect of acetaldehyde and GAGs upon Factor IXa, an intrinsic pathway enzyme, has been investigated. Individually, acetaldehyde, heparins of various molecular weights, dermatan sulfate, and chondroitin sulfates A and C affect Factor IXa, prolonging clotting time as measured by APTT. Pre-incubation of Factor IXa with a mixture of 22.3 mM acetaldehyde and heparin(17k), heparin(6k), dermatan sulfate, or chondroitin sulfate A additively prolongs clotting times, reflecting individual, unrelated molecular mechanistic effects. In contrast, a synergistic effect is observed at the 44.7 mM acetaldehyde level with heparin(17k), heparin(3k), chondroitin sulfates A and C, and dermatan sulfate, suggesting that acetaldehyde may cross-link with the enzyme and the GAGs, forming tertiary complexes, further influencing coagulopathy. These observations upon Factor IXa present a deeper dimension to the anticoagulation effect of alcohol on the coagulation cascade.

Short- and long-term effects of acetaldehyde on plasma

The effect of low concentrations of acetaldehyde on activated partial thromboplastin time (APTT) and prothrombin time (PT) of Accuclot coagulation plasmas was monitored over a prolonged time to mimic effects observed in alcoholism. A prolongation of the APTT from 31.9 +/- 0.7 s to 32.6 +/- 0.9 s (n = 8; P =.007) was observed after a 30-min preincubation time with 140 microM acetaldehyde. However, a minimum of 3.6 mM acetaldehyde was required to extend the APTT from 36.6 +/- 1.0 s to 41.2 +/- 0.8 s (P =.001) over an 18-h exposure time. Plasma acetaldehyde levels as low as 2.24 mM caused elevation of PTs from 12.5 +/- 0.5 s to 14.4 +/- 0.2 s (P =.005) after a 24-h preincubation time. These findings seem to indicate that short-term contact of acetaldehyde with plasma, probably yielding reversible interactions, may interfere with APTTs to a greater extent than long-term contact, which would presumably yield stable, irreversible interactions. In comparing the effects of 8.94, 17.9, 89.4, and 447 mM acetaldehyde on the PTs of Level I, II, and III plasma, the PTs were most increasingly prolonged in Level III plasma and least prolonged in Level I plasma at each acetaldehyde concentration, although the plasmas have comparable protein concentrations. These findings seem to indicate that coagulation factors are sensitive to inactivation by acetaldehyde.

A perspective on acetaldehyde concentrations and toxicity in man and animals

Acetaldehyde (AcH) at a concentration of 593 mM lowers the natural fluorescence of commercial human serum by 12%. It also lowers the fluorescence of a beta-naphthylamine standard curve (recovery) in serum by 17%. These results contrast with earlier reports showing that 447 mM AcH had no effect upon fluorescence of serum or a beta-naphthylamine standard curve in serum. Because 447 mM AcH and 593 mM AcH represent 2.5% and 3.3% AcH, it is apparent that there is a narrow window between which AcH may affect fluorescence by adduct formation with blood components and exogenous fluorophores. Nonetheless, serum has the capacity to bind > 2.5% (> 447 mM) AcH without alteration in fluorescence, suggesting that serum has a great carrying capacity for AcH, undoubtedly in the form of adducts to nucleophiles. These results are discussed in the light of toxicity of AcH and ethanol, the probable significance of the approximately 30 microM free AcH that is reported in chronic alcoholics and the planning of in vitro and in vivo studies with AcH.