Pulmonary Hypertension Associated With Scleroderma and Connective Tissue Disease: Potential Molecular and Cellular Targets

Abstract

Systemic sclerosis (SSc) is characterized by autoimmunity, small-vessel vasculopathy, and fibrosis causing damage in multiple organ systems. Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of SSc, occurring in patients with the limited (lcSSc) and diffuse (dcSSc) forms of the disease and affecting 8% to 15% of patients.12 While pulmonary hypertension associated with connective tissue disease (CTD-PAH) has similar clinical features as idiopathic PAH, 1-year survival and freedom from hospitalization are lower in CTD-PAH.3 SSc-PAH has the worst 1-year survival rate at 82% compared with other connective tissue diseases, including systemic lupus erythematosus, mixed connective tissue disease, and rheumatoid arthritis.34 Despite the recent progress in the development of disease-targeted therapies, patients with SSc-PAH have a poorer response to treatment and a worse prognosis than other subgroups of PAH.1 Autoimmunity and prolonged vasculopathy preceding the development of clinical manifestations of SSc-PAH may play a critical role in the poorer outcome of SSc-PAH patients.1 This article will provide an overview of the recent findings related to cellular and molecular mechanisms associated with the development of PAH, with an emphasis on SSc-PAH.