ALPHA-1-ANTITRYPSIN IS DEGRADED AND NONFUNCTIONAL IN CHRONIC WOUNDS BUT INTACT AND FUNCTIONAL IN ACUTE WOUNDS - THE INHIBITOR PROTECTS FIBRONECTIN FROM DEGRADATION BY CHRONIC WOUND FLUID ENZYMES

Fluid obtained from chronic and acute wounds were examined for the pre sence of fibronectin, alpha 1-antitrypsin, and proteinases capable of degrading both proteins. Immunoblot analysis of fluids from ten chroni c wounds revealed that fibronectin and alpha 1-antitrypsin were degrad ed in nine of ten samples. In contrast, both fibronectin and alpha 1-a ntitrypsin were intact in acute wound fluids. The degradation of the i nhibitor and fibronectin occurred in the same wound fluids, and these two events correlated perfectly. Chronic or acute wound fluid proteins were coupled to benzamidine Sepharose 6B beads and incubated with fib ronectin or alpha 1-antitrypsin. Chronic wound fluid proteins degraded fibronectin in the presence of ethylenediaminetetraacetate, leupeptin , cystatin, and pepstatin but not in the presence of phenylmethylsulfo nyl fluoride. Acute wound fluids and normal human serum did not contai n enzymes capable of degrading fibronectin. These data suggest that se rine proteinases are responsible for fibronectin degradation in chroni c wound fluids. Chronic wound fluids that contained degraded alpha 1-a ntitrypsin also contain proteinases capable of degrading alpha 1-antit rypsin from human serum, Acute wound fluids and normal human serum did not contain enzymes capable of degrading alpha 1-antitrypsin. The inh ibitor from acute wound fluids bound to one of its targets, trypsin. I n contrast, the fragment(s) of alpha 1-antitrypsin from chronic wound fluids did not bind trypsin. Chronic wounds associated with degraded f ibronectin and the inhibitor contained ten- to forty-fold more elastas e activity than acute wounds. The degradation of fibronectin by chroni c wound fluid enzymes was inhibited by al-antitrypsin in a dose-depend ent manner. Collectively, these results demonstrate that there are enz ymes in chronic wounds that perturb the function of alpha 1-antitrypsi n and allow fibronectin degradation by uninhibited serine proteinases.