The protein expression of canstatin in PAH rats was decreased in RV (68.0 ± 9.5% vs. Cont) (p = 0.11, Figure 2A), lung (34.8 ± 11.3% vs. Cont) (p < 0.01, Figure 2B) and kidney (67.9 ± 8.4% vs. Cont) (p = 0.13, Figure 2C) but not left ventricle (LV; 102.4 ± 15.1% vs. Cont) (Figure 2D) or liver (113.1 ± 10.1% vs. Cont) (Figure S1). Here, COL4A2 is linked to pulmonary arterial hypertension.