ESR2 and pulmonary arterial hypertension: ERβ is essential for preserving the ECM composition in the lung, and its loss results in altered lung structure and systemic hypoxia.310 In rat models of MCT-PAH, ERβ activation mitigates vascular remodeling, suppresses inflammation, and improves RV function.313 These mechanisms emphasize the role of ERβ in reducing oxidative damage and maintaining RV resilience during PH progression.