It, thus, appears that in this animal model of PAH, the RV remodelling primarily involves cardiomyocyte hypertrophy, CFs overgrowth, and the myofibroblastic transformation of these cells towards the expression of α-SMA and DDR2 [49], rather than collagen deposition (fibrosis) in the myocardial interstitial spaces [7, 47, 50]. The gene discussed is ACTA1; the disease is pulmonary arterial hypertension.