The macrophage accumulation and IL-6 production are regulated by PTEN, since a study on rats exposed to hypobaric hypoxia has shown that selective inhibition of PTEN in PASMCs increases their proliferation and impairs pulmonary hypertension; highlighting that depletion of PTEN exacerbated macrophage accumulation and IL-6 production (Horita et al., 2013). Here, IL6 is linked to pulmonary arterial hypertension.