Protease inhibition attenuates microvascular dysfunction in postischemic skeletal muscle.

Abstract

Neutrophils accumulate in skeletal muscle subjected to ischemia-reperfusion and appear to contribute to reperfusion-induced microvascular dysfunction. The overall objective of this study was to assess the role of the neutrophilic hydrolytic enzyme elastase in ischemia-reperfusion-induced granulocyte accumulation and microvascular dysfunction in skeletal muscle. We examined the effect of three structurally unrelated elastase inhibitors [eglin C, MeOsuc-Ala-Ala-Val-CH2Cl (MAAPV), or L-658758], administered at the onset of reperfusion, on neutrophil content and the increase in microvascular permeability induced by 4 h of ischemia and 0.5 h of reperfusion in the isolated canine gracilis muscle. Changes in vascular permeability (1 - sigma) were assessed by determining the solvent drag reflection coefficient for total plasma proteins (sigma) in the following groups: 1) 4.5 h of continuous perfusion (nonischemic), 2) ischemia-reperfusion alone, 3) ischemia-reperfusion + eglin C, 4) ischemia-reperfusion + MAAPV, and 5) ischemia-reperfusion + L-658758. Muscle neutrophil content was monitored by assessing tissue myeloperoxidase (MPO) activity in biopsies obtained at the end of the experiments. In nonischemic muscles, 1 - sigma and MPO activity averaged 0.13 +/- 0.03 and 0.7 +/- 0.2 units/g wet wt, respectively. Ischemia-reperfusion was associated with marked increases in microvascular permeability (1 - sigma = 0.39 +/- 0.02) and muscle MPO activity (8.9 +/- 1.2 units/g wet wt) that were attenuated by eglin C, MAAPV, and L-658758 (1 - sigma = 0.21 +/- 0.01, 0.22 +/- 0.02, and 0.21 +/- 0.03, respectively; MPO activity = 2.7 +/- 0.4, 2.1 +/- 0.8, and 2.8 +/- 1.8 units/g wet wt, respectively). These results suggest that granulocyte accumulation in postischemic skeletal muscle is dependent on the release of elastase from activated phagocytic cells. Moreover, neutrophilic elastase appears to play a major role in reperfusion-induced increases in microvascular permeability in skeletal muscle.

• Authors: D L Carden, R J Korthuis
• Journal: The American journal of physiology (Am J Physiol) Vol. 271 Issue 5 Pt 2 Pg. H1947-52 (Nov 1996) ISSN: 0002-9513 [Print] United States
• PMID: 8945913 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Amino Acid Chloromethyl Ketones
• Cephalosporins
• O-methylsuccinyl-alanyl-alanyl-valyl-chloromethyl ketone
• Protease Inhibitors
• Proteins
• Serine Proteinase Inhibitors
• Serpins
• eglin proteinase inhibitors
• L 658758
• Peroxidase
• Pancreatic Elastase
• Leukocyte Elastase

Topics

• Amino Acid Chloromethyl Ketones (pharmacology)
• Animals
• Capillary Permeability
• Cephalosporins (pharmacology)
• Dogs
• Female
• Ischemia (physiopathology)
• Leukocyte Elastase (antagonists & inhibitors, metabolism)
• Male
• Microcirculation (drug effects)
• Muscle, Skeletal (blood supply)
• Neutrophils (enzymology)
• Pancreatic Elastase (antagonists & inhibitors, metabolism)
• Peroxidase (metabolism)
• Protease Inhibitors (pharmacology)
• Proteins
• Reperfusion
• Serine Proteinase Inhibitors (pharmacology)
• Serpins (pharmacology)