Cellular mechanisms of acute hypoxic pulmonary vasoconstriction

Although acute hypoxic pulmonary vasoconstriction (HPV; see Table 1) has been studied intensively for over 50 years, its mechanisms remain unclear. Understanding these mechanisms is important because HPV plays significant roles in both normal and diseased lungs. In normal lungs, HPV maximizes systemic arterial oxygen tension by diverting pulmonary blood flow from poorly ventilated hypoxic lung regions to well ventilated normoxic lung regions. In diseased lungs, where hypoxia is diffuse, HPV occurs throughout the pulmonary vasculature, resulting in pulmonary hypertension, right ventricular failure, and increased morbidity and mortality.