MMP9 and chronic thromboembolic pulmonary hypertension: It was thus shown that CRP [23], interleukin (IL)-10 [23], monocytic chemotactic factor-1 (MCP-1) [24], macrophage inflammatory protein 1α (MIP-1α) [23], matrix metalloproteinase 9 (MMP-9) [23], CXCL-13 [25], neopterin [26], osteopontin [27], endothelial–platelet adhesion molecule 1 (PECAM-1) [28], CXCL-10 [29], CXCL-9 [29], and CCL-5 [29] are significantly increased in patients with CTEPH.