TNF and pulmonary arterial hypertension: Preclinical investigations using models of PAH induced by MCT and hypoxia have linked the activation of the NF-κB pathway to elevated levels of IL-1β, IL-6, and TNF in both serum and lung tissues.214 For instance, at the animal level, a study utilizing an MCT-PAH model in rats demonstrated an increase in the relative expression levels NF-κB p65 in the lungs.