Mesenchymal stem cell effect on lymphocyte apoptosis is partially contact dependent. (P1056)

Abstract

Although a vast evolution in mesenchymal stem cell (MSCs) knowledge and their immunomodulatory properties, still unexplored fields, such as, its effect on T cell death. This study objective was to evaluate MSCs effect on PHA activated lymphocyte (CD3+) apoptosis in vitro. CD3+ co-cultivated with MSC presented less early apoptosis (EA) and late apoptosis/necrosis (LN) determined by Annexin V and Annexin V/Propidium Iodide co-expression, compared to the ones without MSC. After 48hs of MSC co-cultivation CD3+ EA mean was lower (9.1+2.8) then without MSC (12.7+2.0), the same was observed for LN that was lower (28.0+13) then without MSC (41.9+13) p<0.05. To assess if this effect on lymphocytes were contact dependent, the co-cultivation was performed with or without 0.2µm transwell, and we observed that is partially contact, dependent since the CD3+ EA mean after 72hs of MSC co-cultivation (25.0+3.3) was lower than with transwell (32.7+4.0), but both were inferior than without MSC (45.0+7.3). Next, to evaluate cell type specificity, lymphocytes were co-cultivated with MSC, fibroblast and HUVEC. CD3+ cells presented less EA when co-cultured with MSC and fibroblast then with HUVEC. After 72hs of lymphocytes co-cultivation with MSC (n=4) (29.95+0.29) and fibroblast (30.70+1.62) EA were significant lower compared to HUVEC (38.85+1.33) p<0.05. These results have shown that the MSC effect on CD3+ is partially contact dependent, and similar for MSCs and fibroblast, but not for HUVEC.