RESUMO
BACKGROUND: Mesenchymal stromal cells (MSC) have been proposed as a promising complement to standard immunosuppression in solid organ transplantation because of their immunomodulatory properties. The present work addresses the role of adipose-derived MSC (Ad-MSC) in an experimental model of acute rejection in small bowel transplantation (SBT). MATERIAL/METHODS: Heterotopic allogeneic SBT was performed. A single dose of 1.5x106 Ad-MSC was intra-arterially delivered just before graft reperfusion. Animals were divided into CONTROL (CTRL), CONTROL+Ad-MSC (CTRL_MSC), tacrolimus (TAC), and TAC+Ad-MSC (TAC_MSC) groups. Each Ad-MSC groups was subdivided in autologous and allogeneic third-party groups. RESULTS: Rejection rate and severity were similar in MSC-treated and untreated animals. CTRL_MSC animals showed a decrease in macrophages, T-cell (CD4, CD8, and Foxp3 subsets) and B-cell counts in the graft compared with CTRL, this decrease was attenuated in TAC_MSC animals. Pro- and anti-inflammatory cytokines and some chemokines and growth factors increased in CTRL_MSC animals, especially in the allogeneic group, whereas milder changes were seen in the TAC groups. CONCLUSION: Ad-MSC did not prevent rejection when administered just before reperfusion. However, they showed immunomodulatory effects that could be relevant for a longer-term outcome. Interference between tacrolimus and the MSC effects should be addressed in further studies.