Changes of nonspecific proteinases and their inhibitors in different clinical types of myocardial infarction

Purpose: to elucidate the relationships between serum levels of nonspecific proteinases and their inhibitors in patients with complications of myocardial infarction (MI). Material and methods. This prospective short-term study included 82 patients with uncomplicated non-Q wave MI (n=27), Killip I-II Q-MI complicated by acute left ventricular failure (ALVF) (n=30), Killip III-IV Q-MI, and Killip III-IV ALVF (n=17) as well as non-survivors due to development of cardiogenic shock (n=8) and healthy controls (n=12). Serum levels of elastase-like (ELA) and trypsine-like (TLA) activities and of proteinase inhibitors (antitrypsin activity and acid-stable inhibitors) was evaluated by enzymatic method within 24 hours, 3 and 14 days after the onset of symptoms. Risk stratification was done at admission according to the GUSTO Score. Results. The levels of all nonspecific proteinases were elevated in MI patients in comparison to controls. Mean baseline ELA (0.29 vs 0.37 nMol/mL min; р<0.05) and TLA (0.33 vs 0.40 mcMol/mL min; р<0.05) were higher in patients with MI complicated by ALVF than in those with uncomplicated MI. Non-survivors showed significantly higher ELA and TLA and lower levels of proteinase inhibitors than patients with uncomplicated MI. Discussion. Proteolytic enzyme activities varied parallel to the changes of proteinase inhibitor levels. Proteinase activities were much more elevated in non-survirvors than in patients with uncomplicated MI. Decreased proteinase inhibitor levels can be considered as a marker of imbalance of proteinase-inhibitor system. Conclusions. Increase of nonspecific proteinase serum levels within 24 hours after the onset of MI is associated with the development of ALVF and unfavorable prognosis; it suggests the involvement of the proteinase-inhibitor system in pathogenesis of MI.