Effects exerted by mesenchymal stem cells on monocytes obtained from patients with rheumatoid arthritis and progressive systemic sclerosis

In the context of autoimmune inflammatory diseases, the therapeutic benefits of mesenchymal stem cells (MSCs) could be found in their potential to exert immunosuppressive effects and to regulate the immune response. In pursuit of having a more complete look a the regulatory mechanisms performed by AT-MSC, we examined the influence of adipose stem cells (AT-MSC) on blood monocytes from patients with rheumatoid arthritis (RA). Comparison of the effect exerted by the soluble factors produced by AT-MSC vs. cell culture control media, on peripheral blood mononuclear cells (PBMC), showed a significant decrease in the percentage of HLA-DR expressing monocytes, 55.3% (IQR 30-65%) vs. 72% (IQR 62-81%), p = 0.001, as well as a significant decrease in mean fluorescence intensity MFI of HLA-DR was observed, 265 MFI (IQR 102-896 MFI) vs. 473 MFI IQR 160-2201 MFI), p = 0.001. The percentage of CD14 expressing monocytes and CD14 MFI, was increased in PBMC cultured with AT-MSC conditioned media as opposed to control media: 11.7% (IQR 7.6-16.5%) vs. 6.6% (IQR 4.6-11.8%), p = 0.013 and the surface expression density of CD14, 2702 (IQR 1548-3418) vs. 1540 (IQR 1146-2140), p = 0.05. sVEGF-A levels in PBMC cultures from PA patients cultured with conditioned media from AT-MSC were significantly higher than PBMC cultured with control media suppressing secretion of sVEGF-A, 5012 (IQR 2516-5054 pg/ml) vs. 561 pg/ml (IQR 288-699 pg/ml), p = 0.001.