Can Different Intestinal Transplantation Scenarios Alter Radioactive Tracer Uptake In A Rodent Experimental Model? A Preliminary Study

IVANA IVANOFF MARINOFF; MOREIRA JEREMÍAS; VECCHIO DEZILLIO, LEANDRO EMMANUEL; LAUSADA NATALIA; ABATE JUAN CRUZ; RODRIGO PAPA-GOBBI; MACHUCA MARIANA; ELETA MARTÍN; BAMBACCI FLORENCIA; CÚNEO LUCRECIA; GONDOLESI GABRIEL; PABLO STRINGA; MARTÍN RUMBO

Chicago, Illinois

Congreso; 18th Congress of the Intestinal Rehabilitation and Transplant Association; 2023

CIRTA - TTS

Graft rejection is one of the most common complications associated with intestinal transplantation (ITx). The current diagnosis of acute graft rejection (ACR) is made by symptomatology and endoscopic and anatomopathological studies of the intestinal mucosa. This methodology is unable to determine what occurs in all layers and along the whole length of the graft. The search for non-invasive methods for graft monitoring continues to be of much interest. Positron emission tomography (PET) is a non-invasive nuclear medicine imaging approach that allows early detection of manifestations in patients with oncological diseases or infectious processes. During a rejection event, cell populations may increase their glycolytic metabolism, and therefore their capacity to uptake the radioactive tracer F-18 fluorodeoxyglucose (FDG). The aim of this preliminary study is to relate the differences in tracer uptake in different ITx scenarios comparing to the histopathological diagnosis of ACR, to evaluate the potential utility in graft monitoring by the noninvasive PET-scan method.Allogeneic heterotopic ITxs were performed in rats (Sprague Dawley as donor, Wistar as recipient); tacrolimus 0.6 mg/kg/day was administrated subcutaneously for 7 days as immunosuppressive therapy (TAC group, N=3). Controls without interventions (control, n=4) and without immunosuppressant (w/o IS, N=1) were used. Native intestines from each tacrolimus-treated animal were analyzed. The Wu’ score (Wu et al., 2003) was used for histopathological diagnosis of ACR. The PET-scan study was performed in recipients and controls, and FDG uptake was assessed using a standardized parameter (SUV).Histopathological analysis of the graft w/o IS showed alterations compatible with moderate-severe rejection, with epithelial damage and increased mucosal infiltrate, while these same features were observed between 21 and 28 POD in the TAC group. No histological changes compatible with ACR were observed in the control samples and native intestine. The mean ± SEM SUV values were 1.9 ± 0.6, 1.8 ± 0.24, 3.97 ± 0.38 and 12.4 (in control, native, TAC and w/o IS groups, respectively).Despite exhibiting similar histopathological features, the FDG uptake in grafts from animals treated for one week with tacrolimus 0.6 mg/kg/day was reduced three-fold with respect to the allogeneic group w/o IS (p