HIF1A and pulmonary arterial hypertension: Lactate, as a promoter of angiogenesis, increases angiogenesis through HIF-1α stabilization to promote the expression of VEGF (Depping et al., 2008) Furthermore, studies have shown that the progression of PAH is due to VEGF (Wang et al., 2022) and Arginase (Arg) (Ji et al., 2022) overexpression.