CAT and systemic lupus erythematosus: In this study, we aimed to observe and establish an animal model of SLE-associated PAH from weeks 11 to weeks 31, female MRL/lpr (Lupus), to evaluate the role of pulmonary arterial remodeling in SLE, and the mechanisms underlying the suppressive effects of Cat S inhibitors on vascular remodeling were analyzed by α-SMA staining to characterize medial vascular hypertrophy in SLE associated with PAH (SLE-PAH).