Early Tissue Modifications Observed In A Non Immunosuppressed Rat Model Of Abdominal Rectus Fascia Transplant

MOREIRA, JEREMÍAS; STRINGA, PABLO; GENTILINI, MARÍA VIRGINIA; MARTÍN, PEDRO; MILESI, VERÓNICA; ARRIOLA, CONSTANZA; IVANOFF MARINOFF, IVANA; CASTRO, ARACELI; RUMBO, MARTÍN; GONDOLESI, GABRIEL EDUARDO

Chicago, Illinois

Congreso; 17th Congress of Intestinal Rehabilitation and Transplant Association; 2023

CIRTA - TTS

Introduction: The impossibility of performing an adequate closure ofthe abdominal wall after an intestinal or multivisceral transplant increasesthe occurrence of complications and post-surgical death. The use of synthetic meshes can predispose to infections and fistulas, high costs and lowavailability on the market. Within the clinic, the use of different abdominalwall transplantation techniques has been proposed, however, many immunological phenomena are still unknown, the reason why further studies arenecessary. Our aim was to characterize a new experimental model of rectus fascia transplantation.Methods: The technique was developed by reproducing the technicalaspects of “the Miami procedure” for avascular abdominal rectus fasciatransplantation (TxARF) for humans in rats. Eighteen TxARF were performed, 9 were isogenic and 9 allogeneic transplants. Sprague Dawley andWistar rats were used. Recipients were sacrificed on day 30 post-surgeryand graft samples were taken for elasticity measurement, histopathologicalevaluation by Weigert analysis for elastic fibers, Trichromic to stain collagenous connective tissue fibers, and immunohistochemistry for CD3+cells. Six non-implanted fascias were taken as a control group (Ct). Relativeamounts of CD4+ and CD8+ Tcells was determined by flow cytometry.Turnover of hematopoietic cells in the graft was analyzed by flow cytometryusing GFP+Wistar rats as recipients.Results: In the TxARF group, the 30 day survival was 100%; no adhesions between the intestines and the grafts were observed. The presence of neo-vascularization has been observed in all grafts. Isogenic andallogeneic grafts on day 30 presented less elasticity compared to the Ct(p=0.003), although no differences were observed in terms of the numberof elastic fibers observed in TxARF grafts and Ct. The mean percentage ofcollagen fibers stained was more than 10 times higher in the TxARF allogeneic and isogenic groups than in the Ct (p