COL18A1 and pulmonary arterial hypertension: The identified proteins have different roles in the context of PAH: some of them play a role in pulmonary vascular remodeling (RAGE, MMP-2); others are indicative of cardiac dysfunction (NT pro-BNP and IGFBP-7), whereas others are involved in angiogenesis (Collagen IV, endostatin, IGFBP-2, neuropilin-1).