# In-Situ Vascular Regeneration by Host Cells of Acellular Human Saphenous Vein Implanted in Porcine Carotid Artery

## TL;DR

Researchers tested if a decellularized human vein could regenerate into a functional artery in pigs, finding that it worked without needing pre-seeding cells.

## Contribution

Demonstrated that decellularized human saphenous vein can support in-situ vascular regeneration in porcine models without pre-seeding.

## Key findings

- Decellularized human saphenous vein grafts showed signs of vascular regeneration in pigs.
- Pre-seeding with endothelial-like cells did not improve outcomes compared to unseeded grafts.
- Patency rates were 57.1% and 71.4% in unseeded and seeded groups, respectively, at 4 weeks.

## Abstract

Small vascular graft engineering may help reduce early vein graft failure. We assessed the feasibility, safety, and in vivo vascular regeneration potential of the decellularised human saphenous vein (D-hSV) with and without pre-seeding with porcine endothelial-like cells (ELCs) following grafting in porcine carotid artery (CA). A total of 14 pigs received CA grafting of control D-hSVs (n = 7) or D-hSVs seeded with ELCs (SD-hSV; n = 7). Ultrasound vascular Doppler was undertaken before and after grafting, and at 4 weeks. Outcome measures included patency, intimal thickening (IT), in situ vascular regeneration, endothelial cell (EC) coverage, neo-angiogenesis, mesenchymal–EC transition, and contractile cells. All animals reached the predefined culling point in good health, with no feasibility/safety concerns. Mild graft dilatation occurred at 4 weeks vs. baseline, with no difference between groups. In total, 9/14 grafts (64.3%) remained patent at 4 weeks (4/7 (57.1%) vs. 5/7 (71.4%) in the D-hSV and SD-hSV groups, respectively). IT increased from 17.1 ± 4.7% at baseline to 54.1 ± 12.2% at 4 weeks. Vascular regeneration occurred in all patent grafts with EC coverage, an increase in collagen and elastin, vimentin, SM-MHC-11, and calponin, with no difference between groups. The D-hSV for arterial vascular grafting is feasible and safe and associated with signs of in situ vascular regeneration by host cells at 4 weeks. Pre-seeding with ELCs did not add benefits.