Validate Adipose Derived Stem Cells In Vascularized Composite Allotransplantation

Title: In Vitro Comparison of the Immunoregulatory Effects of Bone Marrow and Adipose Derived Stem Cells.Background:Both bone marrow (BMSCs) and adipose-derived (ASCs) mesenchymal stem cells have recently been described to be a promising strategy to promote transplant tolerance. However, the unique immunoregulatory properties of BMSCs and ASCs and their individual ability to suppress an alloimmune response have not been directly compared yet.Methods: BMSCs and ASCs were isolated from Lewis, Brown Norway (BN), and ACI rats. In a mixed lymphocyte reaction (MLR), CFSE-labeled Lewis rat splenocytes were cultured either1) alone,2) with irradiated Lewis splenocytes,3) with irradiated BN rat splenocytes, or4) with phytohaemagglutinin (PHA). Group3and4were further co-cultured with either varying doses of sorted BMSCs, or ASCs from different passages or media harvested from stem cell cultures to assess for immunomodulatory effects. Additionally, in Group3, MSCs were added on day3to the MLR (delayed regulation), or were removed after3-day of co-culture from the MLR (interrupted regulation).Results:BMSCs and ASCs of all strains showed similar biological properties, and displayed low immunogenicity. All allogeneic MLRs showed vigorous cell proliferation as compared to cultured cells from Groups1and2. When added to allogeneic MLRs, both BMSCs and ASCs of different origins (recipient, donor and third party) significantly suppressed allogeneic and PHA stimulation in a dose-dependent manner (p<0.05). ASCs showed superiority in suppressing both allo and non-specific regulation as compared to BMSCs (p<0.05). Stem cell culture media alone, however, did not suppress proliferation of mixed lymphocytes in any group. Moreover, in both delayed and interrupted regulation settings, the suppressive effects diminished to a very limited level (suppression rate:16.22%50.41%vs.83.39%). Interestingly, the MSCs from late passage exhibited lower regulatory potentials (10.91%vs.64.49%).Conclusion: MSCs from different tissue origins exert immunomodulation in allo-and in PHA-induced stimulation, indicating immunoregulatory effects of this type of stem cells are non-specific. In addition, the regulatory potential correlates with cell senescence.