Elevated basic fibroblast growth factor levels in patients with pulmonary arterial hypertension

Study objectives: Cellular growth in the vascular wall, including endothelial and smooth-muscle cell proliferation, is recognized as a component of the obstructive vasculopathy observed in the small vessels of the lungs in pulmonary arterial hypertension (PAH). We hypothesized that angiogenic growth factors may have a role in the molecular mechanisms underlying this cellular proliferation. Design: Case-control study. Setting: Multicenter, tertiary care hospitals. Participants: We studied 117 patients with PAH and 60 control subjects. Measurements: We measured levels of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in the blood and urine of these subjects using an enzyme-linked immunoassay. Results: Median levels of urinary and plasma bFGF were significantly higher in patients with PAH compared to normal control subjects. There was a difference in levels of urine and plasma bFGF according to etiology of pulmonary hypertension, with the highest levels seen in patients with primary pulmonary hypertension. Levels of urine or plasma VEGF were not significantly different between patients and control subjects. Conclusion: Patients with PAH have substantial alterations in urine and plasma levels of bFGF. This molecule may have a role as a mitogenic factor in the endothelial and smooth-muscle cell proliferation seen in PAH.