Evaluation of immunomodulatory effects of co-culture or supernatant of dexamethasone or IFN-γ-treated adipose-derived mesenchymal stem cells on spleen mononuclear cells

Although mesenchymal stem cells (MSCs) have exhibited promising immunomodulatory potential in preclinical studies, clinical studies have revealed variable results. These results often depend on environmental cues. Pre-conditioning MSCs with cytokines is one of the methods used to enhance their immunomodulatory effects. In this study, we harvested adipose-derived MSCs from mice and cultured them with different doses of the cytokine, IFN-γ, and the corticosteroid drug, dexamethasone, in order to investigate their effects on MSC immunosuppressive function. We found the co-culture or supernatant of MSCs, pre-conditioned with IFN-γ, together with spleen mononuclear cells resulted in a significant reduction of mononuclear cell proliferation. Although the supernatant of MSCs, pre-conditioned with dexamethasone, showed similar results, dexamethasone pre-conditioning of co-cultured MSCs increased mononuclear cell proliferation. The results further our understanding of immune-related effects of MSCs which may provide a basis for further in vivo studies to achieve better clinical results. We propose that pre-conditioning with cytokines might be an effective method to boost the immunomodulatory effects of MSCs.

Circulating mesenchymal stem cells, stromal derived factor (SDF)-1 and IP-10 levels increased in clinically active multiple sclerosis patients but not in clinically stable patients treated with beta interferon.

BACKGROUND: Mesenchymal stem cells (MSCs) have the capacity to migrate into the inflammatory regions in response to chemokines such as, IP-10 and SDF-1α and function as anti-inflammatory and immunomodulatory cells. METHODS: In this study we investigated the MSCs frequency in peripheral blood of Relapsing-Remitting Multiple Sclerosis (RRMS) patients in clinically active and not on disease-modifying therapy (DMT) (n = 22) and clinically stable on DMT (Interferon-ß (IFN-ß) therapy) for at least 6 months (n = 22) in comparison to sex and age-matched healthy controls (n = 25) using flow cytometry. The serum and gene expression levels of IP-10 and SDF-1a were also measured in studied groups by ELISA and Real time- PCR. RESULTS: We obtained significant high levels of circulating CD45-CD34- CD90+ and CD45-CD34- CD105+ cells in clinically active patients, not on DMT and patients under IFNß therapy compared with control group. Furthermore, a significant increase in the percentage of circulating CD45-CD34- CD105+ CD90+ cells was found in clinically active patients and not on DMT compared with control group. Serum analysis of IP-10 and SDF-1α showed a significant increase in IP10 concentration in both clinically active not on DMT (P = 0.02) and on DMT (P = 0.005) RRMS patients in comparison with controls. The expression level of SDF-1α mRNA significantly increased in clinically active not on DMT (P = 0.03), while decreased in patients under IFNß therapy (P = 0.04). The mRNA expression of IP-10 only increased in patients on DMT compared with controls (P = 0.05). CONCLUSION: Circulating MSCs, IP-10 and SDF-1α levels, increased in RRMS patients with clinically active not on DMT and IFN-ß therapy reduced circulating MSCs and SDF-1α levels.

Low and high CD8 positive T cells in multiple sclerosis patients.

Cumulating evidence points to a key role for CD8+ T cells in the pathogenesis of multiple sclerosis.CD8 expression level was believed to be present constantly on the surface of human peripheral blood T cells. However, it was shown that peripheral blood lymphocytes may be divided by the level of CD8 expression, into CD8+high and CD8+low T cells. Now it is well established that the CD8low population of CD8+ T cells demonstrates an activated effector phenotype while the CD8+high T cells have been reported to have regulatory function. In this report we used a flow cytometric assay to compare the frequency of these two subsets in multiple sclerosis patients (n=31) with healthy age- and gender-matched controls (n=18). We found that CD8+ T cells and CD8+low T cells significantly increased in secondary progressive (SP) and primary progressive multiple sclerosis (PPMS) patients in comparison to controls (p<0.0002 and p<0.004 respectively) and also RRMS (p<0.005 and p<0.017 respectively). These results demonstrated the role of CD8low T cells in progressive form of multiple sclerosis.