Matrix metalloproteinase-9 concentrations in critically ill patients.

Matrix metalloproteinase-9 is involved in the processing of cytokines during sepsis. We studied 10 critically ill patients within 12 h of fulfilling the American Consensus Conference criteria for severe sepsis and compared the results with 12 critically ill non-septic control patients and eight healthy subjects. Total matrix metalloproteinase-9 concentrations were measured on days 1, 2 and 3. The median admission Acute Physiological and Chronic Health Evaluation II score was 19.5 (range 13-27) in the septic patients and 20.5 (range 7-28) in the non-septic patients. Four patients from each group died within 28 days. Matrix metalloproteinase-9 concentrations were elevated significantly in both groups of patients compared with healthy subjects (p = 0.0004) but there was no difference between patients with and without sepsis. Matrix metalloproteinase-9 levels did not change with time, and there was no difference between survivors and those who died. We conclude that matrix metalloproteinase-9 represents a non-specific marker of systemic inflammation.