Transplant of the Abdominal Rectus Fascia in rats, first report of a novel experimental technique

Abstract

Background: After intestinal or multivisceral transplant, closing the abdominal wall can be challenging, as negative pressure dressing or synthetic meshes pose risks like infections and fistulas. Clinical practice has evolved from vascularized abdominal wall transplants to non-vascularized Abdominal Rectus Fascia (TxARF). Although it was successful, many immunological aspects remain unknown, highlighting the need for further research. Methods: The technique was developed by reproducing the technical aspects of the procedure described for humans in rats (Wistar and Sprague Dawley). Twenty-six Isogenic and Allogeneic TxARF procedures were performed and followed until 30 and 120 post-transplant days (PTD). The non-implanted fascias served as a control group. Rats were then re-assessed for engraftment on 7, 11, 30 and 120 PTD. Fascia samples were taken to assess neovascularization by quantifying cell composition and blood vessels using H&E and Orcein staining. Results: All animals (N=26) survived at 30 and 120 PTD, with 4 (15.4 %) developed subcutaneous serum collection. Upon reoperation, grafts showed neovascularization. No adhesions were observed between the intestines and the grafts. The principal cell compound of the fascia was represented by Fibroblasts (18.35 cells/field) and Myocytes (6.57 cells/field). A significant increment of the number of blood vessels were observed during the period studied (p=0.046). Conclusions: Our report on TxARF in rats, proves the feasibility of this experimental and translational model, showing similar results to those published in the clinical field. Further studies are required to evaluate the immunogenicity as well as the changes in ARF overtime.