The pathobiology of pulmonary hypertension - Endothelium

Mild to moderate pulmonary hypertension (PH) is characterized histologically by medial smooth muscle cell hypertrophy. Sever PH (primary and secondary) is characterized by the presence of intraluminal clusters of endothelial cells in pulmonary arteries. We review the evolving concepts of pulmonary endothelial cell dysfunction in severe PH. Our most recent findings indicate that mutations underlie the endothelial cell proliferation seen in PPH, suggesting that endothelial progenitor-like cells may be activated to grow and eventually disrupt pulmonary artery flow.