However, although Cirp‐KO rats exhibited exacerbated PAH than WT controls, less infiltration of mononuclear cells in lungs was detected (as evaluated with anti‐CD68 antibody staining, Figure S1D), which indicated inflammatory response is not one of the main factors that contribute to aggravated MCT‐induced PAH in Cirp‐KO rats. This evidence concerns the gene CD68 and pulmonary arterial hypertension.