Protease inhibitors in plasma and faecal extracts from patients with active inflammatory bowel disease

The level and functional activity of the major protease inhibitors in plasma and faecal extracts were analysed in 26 consecutive patients admitted during their first attack of acute severe colitis. The patients were retrospectively divided into two groups: one with total colitis and another with distal colitis. The patients with total colitis had a significantly lower alpha 2-macroglobulin level in plasma than normal individuals and patients with distal disease, whereas no difference in the levels of alpha 1-protease inhibitor, antichymotrypsin, antithrombin III, and alpha 2-antiplasmin was noted between the two groups. The protease-inhibiting capacity was saturated, and free proteolytic activity was present in the faecal extracts. In the extracts complex formation was demonstrated between leukocyte proteases and the antiproteases alpha 1-protease inhibitor and alpha 2-macroglobulin. It is concluded that the low plasma level of alpha 2-macroglobulin in patients with severe total colitis is mainly due to a consumption caused by complex formation with proteases, as earlier demonstrated in patients with acute pancreatitis and sepsis.