BACKGROUND: In the past, successful use of decellularized xenogenic tissue was shown in the pulmonary circulation. This study, however, evaluates a newly developed decellularized equine pericardial patch under high pressure circumstances.

MATERIAL AND METHODS: Seven decellularized equine pericardial scaffolds were implanted into the descending aorta of the juvenile sheep. The implanted patches were oversized to evaluate the durability of the decellularized tissue under high surface tension (Law of Laplace). After 4 months of implantation, all decellularized patches were inspected by gross examination, light microscopy (H&E, Serius red, Gomori, Weigert, and von Kossa straining), and immunohistochemical staining.

RESULTS: The juvenile sheep showed fast recovery after surgery. There was no mortality during follow-up. At explantation, only limited adhesion was seen at the surgical site. Gross examination showed a smooth and pliable surface without degeneration, as well as absence of aneurysmatic dilatation. Light microscopy showed a well preserved extracellular scaffold with a monolayer of endothelial cells covering the luminal side of the patch. On the outside part of the patch, a well developed neo-vascularization was seen. Host fibroblasts were seen in all layers of the scaffolds. There was no evidence for structural deterioration or calcification of the decellularized equine pericardial scaffolds.

CONCLUSIONS: In the juvenile sheep, decellularized equine tissue showed no structural deterioration, but regeneration and remodeling processes at systemic circulation.

Keywords: Blood Circulation - physiology, Calcification, Physiologic, Horses, Pericardium - cytology, Prosthesis Implantation, Sheep, Tissue Engineering, Tissue Scaffolds - chemistry