Since VSR is a core pathological change of systemic hypertension and pulmonary hypertension, it is important to further explore its mechanisms in order to better understand its pathogenesis, which would ultimately provide scientific basis for potential therapeutic targets. In vitro and in vivo experiments demonstrated that downregulated SO2/AAT pathway was involved in VSR of systemic hypertension and pulmonary hypertension. This evidence concerns the gene SERPINA1 and pulmonary arterial hypertension.