The co-injection of somatic cells with embryonic stem cells affects teratoma formation and the properties of teratoma-derived stem cell-like cells

Allogenic Use of Human Placenta-Derived Stromal Cells as a Highly Active Subtype of Mesenchymal Stromal Cells for Cell-Based Therapies

The application of mesenchymal stromal cells (MSCs) from different sources, including bone marrow (BM, bmMSCs), adipose tissue (atMSCs), and human term placenta (hPSCs) has been proposed for various clinical purposes. Accumulated evidence suggests that the activity of the different MSCs is indirect and associated with paracrine release of pro-regenerative and anti-inflammatory factors. A major limitation of bmMSCs-based treatment for autologous application is the limited yield of cells harvested from BM and the invasiveness of the procedure. Similar effects of autologous and allogeneic MSCs isolated from various other tissues were reported. The easily available fresh human placenta seems to represent a preferred source for harvesting abundant numbers of human hPSCs for allogenic use. Cells derived from the neonate tissues of the placenta (f-hPSC) can undergo extended expansion with a low risk of senescence. The low expression of HLA class I and II on f-hPSCs reduces the risk of rejection in allogeneic or xenogeneic applications in normal immunocompetent hosts. The main advantage of hPSCs-based therapies seems to lie in the secretion of a wide range of pro-regenerative and anti-inflammatory factors. This renders hPSCs as a very competent cell for therapy in humans or animal models. This review summarizes the therapeutic potential of allogeneic applications of f-hPSCs, with reference to their indirect pro-regenerative and anti-inflammatory effects and discusses clinical feasibility studies.

Identification of embryonic stem cell activities in an embryonic cell line derived from marine medaka (Oryzias dancena)

This study was conducted to identify embryonic stem cell (ESC) activities of a long-term cultured embryonic cell line previously derived from blastula-stage Oryzias dancena embryos. Five sub-cell lines were established from the embryonic cell line via clonal expansion of single cells. ESC activities, including clonogenicity, alkaline phosphatase (AP) activity, and differentiation capacity, were examined in the five sub-cell lines. We observed both clonogenicity and AP activity in all five sub-cell lines, but the proportion of cells that exhibited both properties was significantly different among them. Even though we detected different formation rates and sizes of embryoid body (EB) among these cells, all lines were stably able to form EBs and further induction for differentiation showed their capability to differentiate into other cell types in a spontaneous manner. From this study, we determined that the embryonic cell lines examined possessed heterogeneous ESC activities and can be utilized as a marine model system for fish ESC-based research.

A Comparative Study of the Therapeutic Potential of Mesenchymal Stem Cells and Limbal Epithelial Stem Cells for Ocular Surface Reconstruction

Stem cell-based therapy has become an attractive and promising approach for the treatment of severe injuries or thus-far incurable diseases. However, the use of stem cells is often limited by a shortage of available tissue-specific stem cells; therefore, other sources of stem cells are being investigated and tested. In this respect, mesenchymal stromal/stem cells (MSCs) have proven to be a promising stem cell type. In the present study, we prepared MSCs from bone marrow (BM-MSCs) or adipose tissue (Ad-MSCs) as well as limbal epithelial stem cells (LSCs), and their growth, differentiation, and secretory properties were compared. The cells were grown on nanofiber scaffolds and transferred onto the alkali-injured eye in a rabbit model, and their therapeutic potential was characterized. We found that BM-MSCs and tissue-specific LSCs had similar therapeutic effects. Clinical characterization of the healing process, as well as the evaluation of corneal thickness, re-epithelialization, neovascularization, and the suppression of a local inflammatory reaction, were comparable in the BM-MSC- and LSC-treated eyes, but results were significantly better than in injured, untreated eyes or in eyes treated with a nanofiber scaffold alone or with a nanofiber scaffold seeded with Ad-MSCs. Taken together, the results show that BM-MSCs' therapeutic effect on healing of injured corneal surface is comparable to that of tissue-specific LSCs. We suggest that BM-MSCs can be used for ocular surface regeneration in cases when autologous LSCs are absent or difficult to obtain.

SIGNIFICANCE

Damage of ocular surface represents one of the most common causes of impaired vision or even blindness. Cell therapy, based on transplantation of stem cells, is an optimal treatment. However, if limbal stem cells (LSCs) are not available, other sources of stem cells are tested. Mesenchymal stem cells (MSCs) are a convenient type of cell for stem cell therapy. The therapeutic potential of LSCs and MSCs was compared in an experimental model of corneal injury, and healing was observed following chemical injury. MSCs and tissue-specific LSCs had similar therapeutic effects. The results suggest that bone marrow-derived MSCs can be used for ocular surface regeneration in cases when autologous LSCs are absent or difficult to obtain.