Extracellular Vesicle Dynamics Predicting Vascular Complications and Treatment Response in Systemic Sclerosis

Systemic sclerosis is a multisystem autoimmune disease characterized by vascular dysfunction, immune dysregulation, and progressive tissue fibrosis. Cardiopulmonary complications and peripheral vascular involvement are the principal causes of disability and mortality. Extracellular vesicles (EVs) have emerged as key mediators of paracrine intercellular communication. Preclinical studies further suggest that EVs mediate long-range inter-organ communication through the circulation. However, the inability to directly track EV trafficking in vivo in humans has limited the understanding of their contribution to systemic inter-organ communication. The investigators propose that systemic sclerosis provides a unique human model for investigating circulating EV-mediated inter-organ communication in a multisystem disease. The central hypothesis is that arteriovenous differences in the molecular and cellular characteristics of circulating EVs reflect their dynamic exchange between individual organs and the bloodstream, and that these differences are associated with disease severity. Comparison of EVs across the circulation, rather than relying exclusively on peripheral blood samples, enables a more direct assessment of organ-specific EV release and uptake. Characterizing EV dynamics along the circulatory pathway has the potential to identify novel biomarkers and therapeutic targets for systemic sclerosis while providing fundamental insights into EV-mediated inter-organ communication in humans.

Inclusion Criteria: Male and female patients aged 45-75 years Diagnosis of systemic sclerosis according to the 2013 ACR/EULAR classification criteria High risk of pulmonary arterial hypertension based on the DETECT algorithm Stable treatment with vasoactive, vasodilator, and immunosuppressive therapies for at least 3 months prior to blood sampling Exclusion Criteria: Previous diagnosis of pulmonary arterial hypertension confirmed by right heart catheterization Interstitial lung involvement affecting more than 10% of the lung parenchyma Left-sided heart failure (NYHA class 3-4) Evidence of chronic thromboembolic pulmonary disease on contrast-enhanced CT scan Major contraindications to right heart catheterization or coronary angiography Inability to provide informed consent