Mast cell chymase in pulmonary hypertension.

Mast cells are known to be involved in various types of tissue remodelling but their role in pulmonary hypertension is still poorly understood. Two subtypes of mast cells have recently been identified by demonstrating one protease, chymase. This enzyme might be implicated in vascular remodelling. The changes in mast cells in lung tissue from three patients with primary or secondary pulmonary hypertension were therefore investigated. Compared with tissue from four control subjects the number of mast cells in the three patients was markedly increased, which suggests that chymase containing mast cells are involved in tissue remodelling accompanied by fibrotic changes in primary and secondary pulmonary hypertension.