cathepsin-g and Reperfusion-Injury

Neutrophil activation to release granules containing proteases and other enzymes is a primary cause of tissue damage during ischemia/reperfusion injury. Because the contribution of specific granule enzymes to this injury remains poorly defined, the role of cathepsin G in renal ischemia/reperfusion injury was tested. Bilateral renal ischemia led to the expiration of 64% of wild-type mice within 4 days of reperfusion, whereas all cathepsin G-deficient mice survived. Serum creatinine increased to similar levels at 24 hours after reperfusion and then decreased to background in both groups of mice. Ischemic kidneys from both groups had similar levels of neutrophil infiltration and of CXCL1, CXCL2, and myeloperoxidase protein 9 hours after reperfusion, but at 24 hours, these acute inflammatory response components were decreased more than 50% in kidneys from cathepsin G-deficient versus wild-type mice. Ischemic kidneys from surviving wild-type mice had severe tubular necrosis and tubular cell apoptosis 24 hours after reperfusion with subsequent development of fibrosis 30 days later. In contrast, ischemic kidneys from cathepsin G-deficient mice had a 70% decrease in tubular cell apoptosis with little detectable collagen deposition. These data identify cathepsin G as a critical component sustaining neutrophil-mediated acute tissue pathology and subsequent fibrosis after renal ischemia/reperfusion injury.

Topics: Animals; Apoptosis; Cathepsin G; Cathepsins; Chemokine CXCL1; Chemokines, CXC; Creatinine; Enzyme-Linked Immunosorbent Assay; Fibrosis; In Situ Nick-End Labeling; Inflammation; Kidney; Mice; Neutrophil Infiltration; Peroxidase; Reperfusion Injury; Serine Endopeptidases

Reperfusion injury remains a significant problem after lung transplantation and is thought to be in part mediated by neutrophils. Ulinastatin inhibits release of elastase and cathepsin G from neutrophil granules. We hypothesized that inhibition of these neutrophi endopeptidases (proteases) would attenuate pulmonary reperfusion injury.. With an isolated, whole blood-perfused, ventilated rabbit lung model, we studied the effects of ulinastatin. All lungs were flushed with cold Euro-Collins solution, harvested en bloc, stored inflated at 4 degrees C for 18 hours, and reperfused with whole blood. The 18-hour control lungs (n = 8) were stored and reperfused. Low-dose (n = 8) and high-dose (n = 7) groups were treated with total doses of ulinastatin of 25,000 and 50,000 units, respectively, during flush and reperfusion. An additional control group of lungs (n = 8) was harvested, flushed, and immediately reperfused.. The pulmonary artery pressure was significantly lower in the high-dose group than in the 18-hour control group (36.7 +/- 1.8 vs 44.8 +/- 2.9 mm Hg, p = 0.034). The percentage decrease in dynamic airway compliance was significantly less in the high-dose group than in the 18-hour control group (-13.8% +/- 4.4% vs -25.1% +/- 3.7%, p = 0.032). Both low-dose and high-dose ulinastatin treatments did not result in a significant improvement in oxygenation with respect to the 18-hour control group (72.2 +/- 25.8 vs 32.5 +/- 4.9 mm Hg, p = 0.21).. Ulinastatin diminishes reperfusion injury after 18 hours of hypothermic pulmonary ischemia, with resultant improvements in pulmonary artery pressure and airway compliance. Improvement in pulmonary function after preservation and reperfusion with a neutrophil endopeptidase inhibitor confirms the role of endopeptidases in reperfusion injury and suggests an intervention to reduce their detrimental effects on early graft function.

Topics: Animals; Blood Pressure; Cathepsin G; Cathepsins; Female; Glycoproteins; Hypertonic Solutions; Hypothermia, Induced; Leukocyte Elastase; Lung Compliance; Lung Transplantation; Male; Neutrophils; Organ Preservation; Oxygen Consumption; Pancreatic Elastase; Protease Inhibitors; Pulmonary Artery; Rabbits; Reperfusion; Reperfusion Injury; Serine Endopeptidases; Serine Proteinase Inhibitors; Trypsin Inhibitors