A potent tryptase inhibitor nafamostat mesilate dramatically suppressed pulmonary dysfunction induced in rats by a radiographic contrast medium

Abstract

1 Intravenous injection of ioxaglate (4 g iodine kg 71), an iodinated radiographic contrast medium, caused a marked protein extravasation, pulmonary oedema and a decrease in the arterial partial oxygen pressure in rats. 2 All of these reactions to ioxaglate were reversed by the pretreatment with gabexate mesilate (10 and 50 mg kg 71, 5 min prior to injection) or nafamostat mesilate (3 and 10 mg kg 71 ), in which the inhibition was complete after injection of nafamostat mesilate (10 mg kg 71 ). 3 Both gabexate mesilate and nafamostat mesilate inhibited the activity of puri®ed human lung tryptase, although the latter compound was far more potent than the former. 4 Ioxaglate enhanced the nafamostat-sensitive protease activity in the extracellular¯uid of rat peritoneal mast cell suspensions. 5 Tryptase enhanced the permeability of protein through the monolayer of cultured human pulmonary arterial endothelial cells. Ioxaglate, when applied in combination with rat peritoneal mast cells, also produced the endothelial barrier dysfunction. These eects of tryptase and ioxaglate were reversed by nafamostat mesilate. 6 Consistent with these ®ndings, immuno¯uorescence morphological analysis revealed that tryptase or ioxaglate in combination with mast cells increased actin stress ®bre formation while decreasing VE-cadherin immunoreactivity. Both of these actions of tryptase and ioxaglate were reversed by nafamostat mesilate. 7 These ®ndings suggest that tryptase liberated from mast cells plays a crucial role in the ioxaglateinduced pulmonary dysfunction. In this respect, nafamostat mesilate may become a useful agent for the cure or prevention of severe adverse reactions to radiographic contrast media. British Journal of Pharmacology (2003) 138, 959 ± 967. doi:10.1038/sj.bjp.0705121 Keywords: Radiographic contrast media; vascular hyperactivity; pulmonary edema; endothelial barrier function; tryptase; actin stress ®bre; VE-cadherin Abbreviations: BSA, bovine serum albumin; HBSS, Hank's balanced salt solution; HPAECs, human pulmonary arterial endothelial cells; PAR-2, proteinase-activated receptor-2; PBS, phosphate buered saline; RCM, radiographic contrast media; t-Boc-Phe-Ser-Arg- IntroductionIn spite of increasing use of radiographic contrast media (RCM), no eective prevention or therapy for the anaphylactoid reactions, including bronchospasm, dyspnea, laryngeal oedema and pulmonary oedema accompanying respiratory distress, induced by the intravascular injection of RCM has yet been established. The pulmonary oedema is a serious lifethreatening adverse event, although the incidence is rare. The RCM-induced pulmonary oedema is a non-cardiogenic type and appears to be related to the increase in pulmonary vascular permeability subsequent to the activation of in¯ammatory cascade or the release of a variety of chemical mediators (Bouachour et al., 1991). Although the precise mechanisms underlying the RCM-induced vascular hyperpermeability or pulmonary dysfunction remain to be clari®ed, several lines of evidence have suggested that ...

Mast Cell Tryptase Stimulates DLD-1 Carcinoma Through Prostaglandin- and MAP Kinase-Dependent Manners

“…This finding indicated that DLD-1-proliferating effects of PAR-2 stimulation was mediated by the production of PGs. Nafamostat mesilate was reported to be a very potent inhibitor of human tryptase (10,11,17). Therefore, we determined the antagonizing effects of nafamostat on tryptase-induced proliferation of DLD-1 cells.…”

“…Several serine proteinases such as trypsin or trypsin-like proteinase have been suggested to be candidates for PAR-2 agonist proteinase. Among them, mast cell tryptase was reported to be an agonist proteinase for PAR-2 in vascular endothelial cells (10,11). Mast cells are present in mucosa and submucosal tissue of the gastrointestinal tract and there have been many reports suggesting the involvement of mast cells in the growth of tumor tissues through the stimulation of angiogenesis by the active substances released from mast cells (12 -15).…”

Physiology and Pathophysiology of Proteinase-Activated Receptors (PARs): Role of Tryptase/PAR-2 in Vascular Endothelial Barrier Function

“…We have already found in rats that RCM causes extravasation of plasma proteins in lungs, pulmonary edema (18,19), and respiratory dysfunction characterized by the decrease in arterial PaO 2 and increase in PaCO 2 (20,21) immediately (within 10 min) after intravenous injection. These actions of RCM are partially blocked by histamine H 1 -and H 2 -receptor antagonists, while markedly attenuated by cromoglycate, a mast cell stabilizer, and depletion of mast cells by repeated injection of compound 48 / 80 (22).…”

“…Therefore, the RCM-induced acute lung injury may be mediated by mast cell ingredients. Indeed, RCM stimulates the release of pre-formed chemical mediators such as histamine (23 -26) and tryptase (21,27,28) from mast cells without affecting the release of newly synthesized mediators such as leukotrienes B 4 and C 1 , or prostaglandin D 2 (29,30).…”

“…In cultured monolayer of bovine aortic endothelial cells (BAEC) (15) or human pulmonary arterial endothelial cells (HPAEC) (21), RCM causes a marked and concentration-dependent increase in the permeability of proteins, when it is applied in combination with mast cells. The RCM-induced increase in endothelial permeability is suppressed by cromoglycate and nafamostat (15), thereby suggesting that the barrier dysfunction is mediated predominantly by mast cell tryptase.…”