Epoprostenol Therapy Decreases Elevated Circulating Levels of Monocyte Chemoattractant Protein-1 in Patients with Primary Pulmonary Hypertension

Background: Primary pulmonary hypertension (PPH) is a rare disease characterized by progressively increased resistance of the pulmonary arteries associated with vascular remodeling. Infiltration of inflammatory cells in affected vessels is a common pathological finding. Monocyte chemoattractant protein-1 (MCP-1) is recognized as a potent chemotactic and activating factor for monocytes and leukocytes, but its significance in PPH is unclear. Methods and Results: Serum MCP-1 concentrations were measured in 16 PPH patients and the results were compared with those in 16 normal controls. MCP-1 concentrations in PPH patients (265.6±29.5 pg/ml) were significantly elevated compared with those in normal controls (119.6±6.9 pg/ml, p<0.0001). In 9 patients (3 men, 6 women; mean age, 29±3 years), repeated MCP-1 and hemodynamic measurements were performed prior to and during intravenous epoprostenol therapy. During a mean follow-up period of 7±1 months, MCP-1 concentrations were significantly reduced (288.8±122.8 to 185.9±117.5 pg/ml, p<0.01). Conclusion: Circulating MCP-1 concentrations are increased in PPH patients, but can alleviated by chronic intravenous epoprostenol therapy. The increase in MCP-1 might be one of the important factors responsible for the disease development in patients with PPH.