Matrix metalloproteinase 7 in diagnosis and differentiation of pulmonary arterial hypertension

Pulmonary arterial hypertension is a severe disease for which diagnosis often is delayed. Matrix metalloproteinases have been suggested to play a role in vascular remodeling and pulmonary hypertension development. Our aim was therefore to investigate the potential role of matrix metalloproteinases as biomarkers in diagnosis and differentiation of pulmonary arterial hypertension in relation to various causes of dyspnea and pulmonary hypertension. Using proximity extension assays, 10 matrix metalloproteinases and associated proteins were analyzed in venous plasma from healthy controls (n = 20), as well as patients diagnosed with pulmonary arterial hypertension (n = 48), chronic thromboembolic pulmonary hypertension (n = 20), pulmonary hypertension due to heart failure with preserved (n = 33) or reduced (n = 36) ejection fraction, and heart failure with reduced ejection fraction and heart failure with preserved ejection fraction without pulmonary hypertension (n = 15). Plasma levels of matrix metalloproteinase‐2, ‐7, ‐9, ‐12 and TIMP‐4 were elevated (p < 0.01) in pulmonary arterial hypertension compared to controls. Plasma levels of matrix metalloproteinase‐7 were furthermore lower (p < 0.0081) in pulmonary arterial hypertension than in all the other disease groups, but higher compared to controls (p < 0.0001). Receiver operating characteristic analysis of matrix metalloproteinase‐7 resulted in sensitivity of 58.7% and a specificity of 83.3% for detecting pulmonary arterial hypertension among the other disease groups. Plasma matrix metalloproteinase‐7 may provide a potential new diagnostic tool to differentiate pulmonary arterial hypertension from other causes of dyspnea, including heart failure with or without pulmonary hypertension and healthy controls. Matrix metalloproteinase‐7 may furthermore be involved in the development of pulmonary hypertension and pulmonary arterial hypertension. Future studies investigating the clinical usefulness of matrix metalloproteinase‐7 in the differentiation and earlier diagnosis of pulmonary arterial hypertension, as well as its relationship to pulmonary arterial hypertension pathogenesis, are encouraged.