Researchers found that a protein called R‑Ras, when attached to a fatty group (palmitoylation), shows up more in tiny blood‑borne particles (extracellular vesicles) of people with peripheral artery disease (PAD). Higher levels of this modified protein in the blood correlate with age, smoking, high blood pressure, and how bad the PAD is, suggesting it could serve as a blood test marker for the disease.

Human peripheral artery disease (PAD) is common and associated with amputation, heart attack, stroke, and death. Treatment options are limited by inadequate understanding of disease pathophysiology and lack of early detection strategies. R-Ras, which regulates vascular integrity, undergoes reversible palmitoylation. In mice, disrupting this process by inhibiting the enzyme acyl-protein thioesterase 1 (APT1) impairs vascular function and promotes experimental PAD. In arteries from humans with PAD we found increased palmitoylated R-Ras, which correlated with age and hypertension. Extracellular vesicles (EVs) isolated from APT1-knockdown endothelial cells were enriched in R-Ras protein, suggesting that palmitoylation promotes incorporation of R-Ras into EVs. PAD patients compared to subjects without PAD had increased serum EV R-Ras content that was positively associated with age, smoking, hypertension, and PAD severity. These findings suggest that altered R-Ras palmitoylation impacts human PAD and that EV-associated R-Ras may be an accessible biomarker for human PAD.