Increased plasma monocyte chemoattractant protein-1 level in idiopathic pulmonary arterial hypertension

Objective: Monocyte chemoattractant protein-1 (MCP-1), a pro-inflammatory chemokine, has potent chemoattractant activity for monocytes/macrophages. We sought to investigate the clinical significance of MCP-1 in idiopathic pulmonary arterial hypertension (IPAH). Methods: This study included 28 patients with IPAH, seven patients with pulmonary arterial hypertension (PAH) related to collagen vascular disease, and 13 healthy subjects. Plasma MCP-1 levels were measured together with serum IL-6 and tumour necrosis factor-alpha (Tau Nu F-alpha) levels. Results: Circulating levels of MCP-1, IL-6 and Tau Nu F-alpha were significantly higher in patients with IPAH than in healthy controls, although they were lower than in patients with PAH related to collagen vascular disease. Plasma MCP-1 did not significantly correlate with any haemodynamic variables. However, plasma MCP-1 levels correlated negatively with the disease duration (time from symptom onset). Conclusions: Plasma MCP-1 levels were elevated in patients with IPAH, and this elevation was particularly marked in the early stage of disease. Taking into account the chemoattractant activity of MCP-1, these results imply a contribution of MCP-1 to the development of pulmonary hypertension.