fibrinopeptide-b and Pleural-Effusion

The ability of various peptides cleaved by plasmin from human fibrinogen and fibronectin or fibrinogen- and fibronectin- related synthetic peptides to induce histamine release from mast cells and collagenase and elastase from PMN-leukocytes was examined. Low molecular weight fibrinogen degradation products showed dose dependent secretion of collagenase. These peptides (mol. wt. 1.4 kD) at the concentration of 10(-5) M released about 47% of collagenase and 13% of elastase. Synthetic fibrinopeptides A and B had a similar strong collagenase releasing potency and also released histamine from mast cells. Peptides from plasmin digestion of fibronectin containing cell attachment site with sequence Arg-Gly-Asp-Ser and also synthetic peptide reproducing this amino-acid sequence at the concentration of 1000 micrograms/ml released about 50% of collagenase and 55% of elastase from PMN-leukocytes. Moreover peptides containing cell attachment and gelatin binding site induced histamine release from mast cells. The association of fibrinogen and fibronectin degradation with activation of mast cells may motivate the treatment with antihistaminic drugs of all pathological conditions where the intensive protein degradation takes place.

Topics: Animals; Ascitic Fluid; Cell Degranulation; Collagenases; Fibrinopeptide A; Fibrinopeptide B; Fibronectins; Histamine Release; In Vitro Techniques; Male; Mast Cells; Models, Biological; Neutrophils; Pancreatic Elastase; Pleural Effusion; Rats; Rats, Wistar

Pleural fluid from an early, active phase of BCG-induced pleurisy was compared with fluid from late, healing phase, characterized by fibrinous adhesions. Exudates were tested for proteolytic activity on chromogenic peptide substrates designed for plasmin, tissue plasminogen activator, factor Xa, thrombin and plasma kallikrein. Considerable activity of active-phase pleural fluid was found on all of these substrates, and significantly lower values in the healing phase. Most exudates from both stages had very low fibrinogen concentration. Fibrinopeptide A, fibrinolytic products and antiplasmin were found in all exudates. Little or no fibrinolytic effect of pleural fluid was demonstrable on plasminogen free fibrin plates, despite the high activities on the low molecular weight substrates. Occurrence of alpha 2-macroglobulin-enzyme complexes is suggested as an explanation. The experimental results indicate that protease of the fibrinolytic and coagulation systems are active in the chronic inflammation of pleurisy, with higher levels of activity in active pleurisy phase.

Topics: alpha-2-Antiplasmin; Animals; Blood Coagulation; Factor X; Factor Xa; Female; Fibrinogen; Fibrinolysin; Fibrinolysis; Fibrinopeptide A; Fibrinopeptide B; Guinea Pigs; Kallikreins; Male; Mycobacterium bovis; Plasminogen Activators; Pleural Effusion; Thrombin; Tuberculosis, Pleural