Decellularised Veins as a Scaffold for in situ Vascular Tissue Engineering

Abstract

Development of new arterial-like vascular conduits for coronary and peripheral bypass grafting surgery is desirable to overcome the limitations of currently available biological and/or synthetic grafts; to reduce the incidence of early thrombosis, late intimal thickening and infection. One alternative is to use arterialised decellularised venous scaffolds. The aim of this PhD project was to assess the feasibility and suitability of human saphenous vein (hSV) decellularisation as a way to obtain effective biological cellular scaffold for vascular grafting. We identified the optimal sodium dodecyl sulphate (SDS) concentration needed to decellularise short segments of hSVs (~0.5 cm). Low concentration (0.01%) (w/v) SDS removed most of the nuclei, but this approach was not effective in removing nuclei when using ~4 cm long hSVs. Hence, a modified flow technique of decellularisation was established with successful decellularisation of longer hSV segments. Biocompatibility and integrity of decellularised hSVs were then evaluated. Methylene blue assay detected only trivial residual concentrations of SDS after decellularisation. This was biocompatible as this residual amount of SDS did not affect the viability of
porcine carotid artery endothelial cells (pCA ECs) to populate the acellular hSV
(AlamarBlue) and to proliferate (EdU proliferation assays). Next, the ECM integrity of acellular hSVs was assessed by quantifying major ECM proteins (collagen, elastin and glycosaminoglycan). Results revealed that decellularisation with ≤0.01% (w/v) SDS did not have a significant impact on ECM content. We then tested the feasibility, safety and capacity of acellular hSVs to arterialise following surgical implant with end-to-end anastomoses in pig without immunosuppression. This pilot study showed that porcine carotid artery xenograft of decellularised hSV was feasible and safe, with 50% graft
patency rate at 4 weeks and signs of in situ vascular tissue engineering by host cells. In conclusion, effective decellularisation of hSV is feasible, safe and reproducible as potential acellular vascular scaffolds. Acellular hSVs may be used as vascular acellular scaffolds either for in situ vascular engineering by host cells or following ex vivo manipulation before implantation. However, this approach warrants further investigations.

Date of Award	23 Jan 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Raimondo Ascione (Supervisor), Sarah J George (Supervisor) & Saadeh Suleiman (Supervisor)