CXCR4 and pulmonary arterial hypertension: Pulmonary vascular expression of both CXCL12 and CXCR4 has been demonstrated in lungs from rats with Sugen/hypoxia PH and in patients with PAH (80) and inhibition of the expression or binding of CXCR4/CXCL12 reverses MCT-induced PH in rats (81).