α1-Antitrypsin Is Degraded and Non-Functional in Chronic Wounds But Intact and Functional in Acute Wounds: The Inhibitor Protects Fibronectin from Degradation by Chronic Wound Fluid Enzymes

Abstract

Fluid obtained from chronic and acute wounds were examined for the presence of fibronectin, alpha 1-antitrypsin, and proteinases capable of degrading both proteins. Immunoblot analysis of fluids from ten chronic wounds revealed that fibronectin and alpha 1-antitrypsin were degraded in nine of ten samples. In contrast, both fibronectin and alpha 1-antitrypsin were intact in acute wound fluids. The degradation of the inhibitor 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 fibronectin 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 phenylmethylsulfonyl fluoride. Acute wound fluids and normal human serum did not contain enzymes capable of degrading fibronectin. These data suggest that serine proteinases are responsible for fibronectin degradation in chronic wound fluids. Chronic wound fluids that contained degraded alpha 1-antitrypsin also contain proteinases capable of degrading alpha 1-antitrypsin from human serum. Acute wound fluids and normal human serum did not contain enzymes capable of degrading alpha 1-antitrypsin. The inhibitor from acute wound fluids bound to one of its targets, trypsin. In contrast, the fragment(s) of alpha 1-antitrypsin from chronic wound fluids did not bind trypsin. Chronic wounds associated with degraded fibronectin and the inhibitor contained ten- to forty-fold more elastase activity than acute wounds. The degradation of fibronectin by chronic wound fluid enzymes was inhibited by alpha 1-antitrypsin in a dose-dependent manner. Collectively, these results demonstrate that there are enzymes in chronic wounds that perturb the function of alpha 1-antitrypsin and allow fibronectin degradation by uninhibited serine proteinases.

Acceleration of Cutaneous Wound Healing by Transient p53 Inhibition

“…As a result, wounds of PFT-␣-treated animals exhibited a thicker and more cellular granulation tissue than wounds of vehicle (DMSO)-treated animals. The higher leukocytic recruitment in wounds of PFT-␣-treated animals may in addition contribute to the enhanced wound repair, because this inflammatory response ensues the microenvironment suitable for tissue reparation (Kainulainen et al, 1998;Rao et al, 1995) and predicts, as given in the present correlation analysis, the extent of epithelialization.…”

Neutrophils and Wound Repair: Positive Actions and Negative Reactions

“…Interestingly, a1-antitrypsin has been shown to be active in fluid collected from acute wounds, but is degraded in chronic wounds. 22,43 The degradation and inactivity of a1-antitrypsin likely contributes to excessive serine protease activity in chronic wounds. SLPI is another protease inhibitor produced by neutrophils as well as epithelial cells.…”

Inhibition by the Soluble Syndecan-1 Ectodomains Delays Wound Repair in Mice Overexpressing Syndecan-1

“…fluids may be one of the reasons why wounds do not heal even when treated with exogenous matrix and growth factors (2,(31)(32)(33). Migrating keratinocytes at the wound edge and neutrophils migrating to the wound site produce a variety of matrix metalloproteases (34 -37) and serine proteases (38,39) that help cells to migrate and cover the wound.…”