Preclinical testing of acellular and polyphenol-stabilized arterial xenografts in sheep

Cardiovascular disease is a global leading cause of death, prompting coronary heart diseases and peripheral artery diseases due to atherosclerotic artery narrowing. Currently, the most used vascular grafts are autologous arteries and veins. While considered the gold standard for small-diameter vascular replacements (<6 mm), these autologous vessels have limitations, including the need for invasive harvesting and unsuitability for some patients. Tissue-engineered vascular grafts have become a possible treatment in future cardio-vascular graft surgery. These grafts are designed to incorporate living cells, allowing for physiological remodeling.

Cell-free porcine vascular xenografts were implanted surgically into the left carotid arteries of seven recipient sheep, and the subsequent inflammatory and clinical responses were monitored over the following 12 weeks. All seven sheep were euthanized humanely after that period, and a histological examination of the implant site was carried out.

Results showed that endothelial cells had colonized the luminal surface of the cell-free scaffold, and evidence of calcification associated with the transplant site was absent. This indicates that the material is biocompatible and capable of being repopulated. In two recipients, thrombus occlusions formed.

We conclude that using a three-dimensional cell-free porous arterial grafting technique may have the potential for in vivo host cellular repopulation in arterial graft surgical treatments.