Changes in concentrations of type IV collagen and tissue inhibitor of metalloproteinase-1 in patients with paraquat poisoning

Respiratory failure is one of the major causes of death in patients with paraquat poisoning. In paraquat-poisoned lungs, abnormal extracellular matrix regulation occurs. The aim of the present study is to determine whether serum concentrations of type IV collagen and tissue inhibitor of metalloproteinase-1 (TIMP-1) are altered during the course of paraquat poisoning and whether haemoperfusion therapy affects these concentrations. Twenty-one patients were admitted within 3 h after ingestion of paraquat and all patients received direct haemoperfusion therapy. Five out of 21 patients survived and 16 patients died within 28 days. Plasma paraquat concentrations in nonsurvivors (5740 ± 380 µg l-1) were not significantly different from those in survivors ( 5920 ± 280 µg l-1) before treatment. Haemoperfusion reduced these concentrations in both non-survivors (120 ± 7 µg l-1) as well as survivors (136 ± 9 µg l-1) on day 5. Serum concentrations of type IV collagen and TIMP-1 in survivors showed little change between day 1 (type IV collagen, 90.4 ± 3.6 ng ml1; TIMP-1, 172.2 ± 7.0 ng ml-1) and day 5 (type IV collagen, 92.6 ± 4.2 ng ml-1; TIMP-1, 174.2 ± 7.2 ng ml-1). In contrast, these concentrations in non-survivors on day 5 (type IV collagen, 143.6 ± 7.8 mg ml-1; TIMP-1, 246.8 ± 13.6 ng ml-1) were significantly higher than those on day 1 (type IV collagen, 88.4 ± 4.2 ng ml-1, P < 0.01; TIMP-1, 170.6 ± 9.2 ng ml-1, P < 0.05). These data suggest that serum concentrations of type IV collagen and TIMP-1 may be useful indicators for the development of respiratory failure in patients with paraquat poisoning.