In animal studies, Guo et al. [21] found that in monocrotaline (MCT)-treated rats, which develop severe PAH, the observed increased oxidative stress caused decreased pyruvate kinase isoenzyme type M2 (PKM2) activity, resulting in increased proliferation of pulmonary artery smooth muscle cells (PASMCs). The gene discussed is PKM; the disease is pulmonary arterial hypertension.