Human Amniotic Mesenchymal Stromal Cells Research Articles

Amniotic membrane and amniotic cells: Potential therapeutic tools to combat tissue inflammation and fibrosis?

In addition to the placenta, umbilical cord and amniotic fluid, the amniotic membrane is emerging as an immensely valuable and easily accessible source of stem and progenitor cells. This concise review will focus on the stem/progenitor cell properties of human amniotic epithelial and mesenchymal stromal cells and evaluate the effects exerted by these cells and the amniotic membrane on tissue inflammation and fibrosis.

Human Mesenchymal Stem Cells from Adipose Tissue and Amnion Influence T-Cells Depending on Stimulation Method and Presence of Other Immune Cells

Mesenchymal stem cells (MSCs) are multipotent progenitor cells exerting immunomodulatory effects on cells of the innate and adaptive immune system. It has been shown that an inflammatory milieu is required for the activation of MSC-mediated immunomodulation, and interferon-γ (IFN-γ) plays an important role in this process. We determined the influence of IFN-γ on human adipose-derived stem cells (ASCs) and human amniotic mesenchymal stromal cells (hAMSCs). We further evaluated the effect of MSCs on stimulated T-cells and peripheral blood mononuclear cells (PBMCs) in a cell-contact independent setting. On IFN-γ treatment, ASCs and hAMSCs possessed significantly higher antiproliferative properties and showed surface characteristics of nonprofessional antigen presenting cells (HLA-DR(+)CD40(med+)CD54(high)) with a possible regulatory phenotype (PD-L1(+)PD-L2(+)). The effect of ASCs and hAMSCs on cytokine secretion and T-cell activation was dependent on stimulation method and cellular context. Although ASCs and hAMSCs highly inhibited cytokine secretion of stimulated PBMCs, this was not observed in the case of purified T-cells. The presence of ASCs even favored the secretion of pro-inflammatory cytokines including IFN-γ by T-cells, although T-cell proliferation was efficiently inhibited. Further, ASCs enhanced the number of CD69(+) T-cells independent of the stimuli and cellular context. Interestingly, ASCs significantly suppressed CD25 expression on phytohemagglutinin stimulated PBMCs but had no effect on αCD3/αCD28 stimulated cells. Depending on the stimulation method and cellular context, immune cells create a specific cytokine milieu in vitro, thus differently influencing MSCs and, in turn, affecting their action on immune cells.

Human mesenchymal stem cells and renal tubular epithelial cells differentially influence monocyte-derived dendritic cell differentiation and maturation

Mesenchymal stem cells (MSCs) possess immunosuppressive properties. But also fully differentiated human renal tubular epithelial cells (RTECs) are able to modulate T-cell proliferation in vitro. In this study we compared two MSC populations, human adipose derived stem cells (ASCs) and human amniotic mesenchymal stromal cells (hAMSCs), and RTECs regarding their potential to inhibit monocyte-derived dendritic cell (DC) differentiation and maturation in indirect co-culture. In the presence of hAMSCs and RTECs, monocytes stimulated to undergo DC differentiation were inhibited to acquire surface phenotype of immature and mature DCs. In contrast, ASCs showed only limited suppressive capacity. Secretion of IL-12p70 was suppressed in hAMSC co-cultures and high IL-10 levels were detected in all co-cultures. Prostaglandin E 2 was found in ASC and hAMSC co-cultures, whereas soluble human leukocyte antigen-G was highly elevated only in RTEC co-cultures. Thus, inhibition of DC generation by MSCs and RTECs might be mediated by different soluble factors.