Then, as demonstrated in Figure 2D, after the densities of the PRDC bands on Western blotting are normalized to the density of the corresponding GAPDH band, further linear regression analysis revealed that lung PRDC protein level negatively correlated with the severity of MCT-PAH as measured by RVSP, PASP, mPAP and RVHI. This evidence concerns the gene GREM2 and pulmonary arterial hypertension.