Peritonitis increases MMP-9 activity in peritoneal effluent from CAPD patients

Patients undergoing long-term continuous ambulatory peritoneal dialysis (CA PD) sometimes experience ultra-filtration failure. Mesothelial basement mem brane thickening and the accumulation of submesothelial fibrotic tissue are common features of the diseased peritoneum, Peritonitis can lead to ultraf iltration failure, but the precise mechanism is not clear, The key enzymes in extra-cellular matrix (ECM) remodeling, namely matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), are produced b y human peritoneal mesothelial cells. Using peritoneal effluent from 13 CAP D patients with peritonitis and 7 noninfected CAPD control individuals, we examined MMP and TIMP activities by gelatin and reverse zymography. Latent and activated types of MMP-2 and -9, and TIMP-1 and -2 were identified in p eritoneal effluent (from all CAPD patients). Levels of latent and activated type MMP-9, as well as of TIMP-1 activities were higher at the onset of pe ritonitis than either during the recovery phase of peritonitis and/or in co ntrol individuals. Activated MMP-9 activity positively correlated with leuk ocyte numbers and IL-6 levels in peritoneal effluent. Activities of MMP-2 a nd TIMP-2 in peritoneal effluent did not change between the onset of perito nitis and recovery. We concluded that increased MMP-9 and TIMP-1 levels mig ht be associated with peritoneal ECM remodeling during peritonitis. Copyrig ht (C) 2001 S. Karger AG, Basel.