Extracellular Vesicle Dynamics Predicting Vascular Complications and Treatment Response in Systemic Sclerosis (EVOLVE-SSc)

Extracellular Vesicle Dynamics Across the Circulatory System as Predictors of Major Vascular Complications and Therapeutic Response in Systemic Sclerosis Patients

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Systemic Sclerosis; Pulmonary Arterial Hypertension; Vascular Complications; Digital Ulcers
• Intervention / Treatment: Diagnostic test: Blood sampling, nailfold capillaroscopy

Detailed Description

Systemic sclerosis (SSc) is a multi-organ disease characterized by vascular, immune, and fibrotic changes. Vascular complications significantly contribute to mortality, disability, and healthcare costs in patients with SSc. These include digital ulcers (DUs) and associated conditions such as gangrene and osteomyelitis, as well as pulmonary arterial hypertension (PAH), all of which continue to have poor outcomes despite treatment advances. Notably, severe vascular disease increases the risk of cardiac and peripheral atherosclerosis, even in the absence of symptoms or overt risk factors. Timely management improves outcomes, but screening and prognostic stratification tools for SSc remain limited. Evidence supporting personalized treatment selection among currently available therapies is lacking.

Extracellular vesicles (EVs) are subcellular particles that facilitate the transfer of proteins, nucleic acids, and lipids between cells. They have been explored as biomarkers, therapeutic targets, and drug carriers across a wide range of diseases.

The investigators hypothesize that EVs play a direct and distinct role in the pathophysiology of multiorgan complications in SSc, particularly PAH and DUs. This hypothesis is supported by preclinical evidence demonstrating the involvement of EVs in endothelial dysfunction, intimal proliferation, immune dysregulation, and fibrosis, which are key processes in SSc pathogenesis. In mouse models, intravenously administered EVs are primarily taken up by the lungs, and PAH can be induced in healthy mice by injecting EVs isolated from pulmonary hypertensive animals. In humans, circulating EVs in the peripheral blood of patients with PAH are more abundant and exhibit distinct proteomic and transcriptomic profiles compared with those of healthy controls. Preliminary evidence further suggests that EV profiles in the venous blood of patients with SSc may correlate with disease severity and activity, although data specifically addressing vascular complications remain limited.

EVs exert biological effects through their protein, nucleic acid, and lipid cargo, as well as their ability to reach and interact with target cells. Recent studies in transgenic zebrafish have demonstrated that endogenous EVs can extravasate to distant target tissues in vivo. However, direct tracking of EVs in humans remains technically unfeasible with current methods. As a surrogate for in vivo tracking, the investigators propose characterizing circulating EVs at specific vascular locations accessible through acral vessels and during clinically indicated procedures such as right heart catheterization (RHC) and coronary angiography. These procedures, recommended for the assessment of PAH in patients with SSc, are consistent with international guidelines and pose no additional risk, making SSc an ideal model for investigating EV dynamics in humans.

This study aims to map EV characteristics across the circulatory system by evaluating changes at key anatomical sites. Sampling locations include the pulmonary artery and ascending aorta, reflecting pulmonary circulation and cardiac EV exchange, and the peripheral radial artery and cephalic vein, representing EV exchange within the acral circulation. EV profiles at these locations are expected to differ as a result of intravasation, extravasation, and collateral blood flow. Current approaches, which rely exclusively on peripheral venous sampling, lack this regional specificity and capture only the aggregate EV output.

The investigators further propose a comprehensive structural and functional evaluation of the cardiopulmonary and peripheral vascular systems to address the complex and heterogeneous nature of SSc complications. Pulmonary hypertension (PH) may arise from pulmonary vascular disease, including PAH or, less commonly, pulmonary veno-occlusive disease (group 1 PH); SSc-associated cardiac disease, including myocarditis, microvascular dysfunction, or accelerated coronary artery disease (group 2 PH); interstitial lung disease (group 3 PH); or, less frequently, chronic thromboembolic disease (group 4 PH). Similarly, DUs may result from microcirculatory failure or accelerated peripheral atherosclerotic disease. Defining the contribution of these overlapping mechanisms in individual patients is essential for interpreting and generalizing EV-related findings.

The unique characteristics of SSc among human diseases may provide broader insights into EV dynamics within the human circulatory system, potentially informing future research on other vascular and multiorgan diseases.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Diagnosis of systemic sclerosis according to the 2013 ACR/EULAR classification 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.

Diagnostic test: Blood sampling, nailfold capillaroscopy; Blood collection during right heart catheterization

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Transcardiopulmonary extracellular vesicle gradient	Arteriovenous differences between the pulmonary artery and the ascending aorta in extracellular vesicle characteristics, including particle concentration, size distribution, protein expression profile, and RNA expression profile. Treatment failure in patients with pulmonary arterial hypertension at 24 weeks, defined as the occurrence of at least one of the following events: an improvement of less than 30 meters in the 6-minute walk distance (6MWD); a reduction in NT-proBNP of less than 30% in patients with baseline levels >300 pg/mL; worsening of World Health Organization (WHO) functional class; or death due to complications of pulmonary arterial hypertension. Treatment failure in patients with recurrent digital ulcers, defined as the development of new digital ulcers or gangrene at sites previously affected by digital ulcers.	Periprocedural (during right heart catheterization).
Peripheral extracellular vesicle gradient	Arteriovenous differences between the cephalic vein and the radial artery in extracellular vesicle characteristics, including particle concentration, size distribution, protein expression profile, and RNA expression profile.	Periprocedural.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Treatment failure in participants with pulmonary arterial hypertension.	Treatment failure, defined as the occurrence of at least one of the following: improvement in 6-minute walk distance of less than 30 meters; reduction in NT-proBNP of less than 30% in participants with baseline NT-proBNP >300 pg/mL; worsening of World Health Organization functional class; or death related to pulmonary arterial hypertension.	24 weeks.
Treatment failure in participants with recurrent digital ulcers.	Development of new digital ulcers or gangrene at sites previously affected by digital ulcers.	24 weeks.

Collaborators and Investigators

• Sponsor: Fondazione Policlinico Universitario Agostino Gemelli IRCCS

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: July 9, 2026
• First Submitted That Met QC Criteria: July 16, 2026
• First Posted (Actual): July 21, 2026

Study Record Updates

• Last Update Posted (Actual): July 21, 2026
• Last Update Submitted That Met QC Criteria: July 16, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Connective Tissue Diseases; Respiratory Tract Diseases; Lung Diseases; Skin Diseases; Hypertension, Pulmonary; Skin and Connective Tissue Diseases; Pulmonary Arterial Hypertension; Scleroderma, Systemic; digital ulcers; Investigative Techniques; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Diagnostic Imaging; Diagnostic Techniques, Cardiovascular; Microscopy; Intravital Microscopy; Blood Specimen Collection; Microscopic Angioscopy
• Other Study ID Numbers: 27513

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: All data will be shared, excluding the patient's first and last name.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No