RPS27A and connective tissue disorder: However, several studies have identified considerable upregulation of RPS27A expression in the left ventricular myocardium of rats suffering from end-stage PAH (MCT-induced PAH rat model), and abnormal expression of RPS27A has been detected in the peripheral blood of patients with connective tissue disease-associated PAH, and its key regulatory role in the pathogenesis of PAH has been identified (Hołda et al., 2020; Tu et al., 2022).