AIM:
Peripheral artery disease (PAD) is a common manifestation of systemic atherosclerosis affecting peripheral arteries. The underlying pathology of PAD are disorganized extracellular matrix (ECM), caused by inflammation and oxidation. Previous studies have demonstrated an important structure disorganization of the arterial tissue due to inflammatory and oxidative processes. Extracellular matrix (ECM), which is a dynamic structure, is an important part of the arterial tissue and helps to maintain its biomechanical properties. Our objectives were to investigate the structural ECM changes during atherosclerosis, and assess non-invasive ECM biomarkers as a diagnostic tool to differentiate between the different stages of PAD.

METHODS:
An histological examination was performed by Haematoxylin and eosin, Masson’s trichrome and Sirius red staining in healthy controls and PAD arteries. A quantitative proteomic study of human PAD and control arteries was performed by iTRAQ isobaric tag labelling and mass spectrometry based on nanoLC-Orbitrap technology. Specific neo-epitope ELISA biomarkers of ECM degradation (VCANM, C4M, LAM-a5, MIM, aSMA, CRPM) were measured in serum samples of PAD patients segregated by Fontaine classification.

RESULTS:
Histological analyses revealed a disorganization of arteries structures (A). Proteomics results showed important differences of extracellular matrix-related peptides between control and PAD arteries (B). The neo-epitope specific biomarkers reflected an accelerated turnover of VCANM, C4M and Lam-a5 with disease activity, being C4M the best biomarker to discriminate between Fontaine groups (C).