Regenerative potential of partially differentiated mesenchymal stromal cells in a mouse model of a full-thickness skin wound

Macroscopic, Histologic, and Immunomodulatory Response of Limb Wounds Following Intravenous Allogeneic Cord Blood-Derived Multipotent Mesenchymal Stromal Cell Therapy in Horses

Limb wounds are common in horses and often develop complications. Intravenous multipotent mesenchymal stromal cell (MSC) therapy is promising but has risks associated with intravenous administration and unknown potential to improve cutaneous wound healing. The objectives were to determine the clinical safety of administering large numbers of allogeneic cord blood-derived MSCs intravenously, and if therapy causes clinically adverse reactions, accelerates wound closure, improves histologic healing, and alters mRNA expression of common wound cytokines. Wounds were created on the metacarpus of 12 horses. Treatment horses were administered 1.51-2.46 × 10⁸ cells suspended in 50% HypoThermosol FRS, and control horses were administered 50% HypoThermosol FRS alone. Epithelialization, contraction, and wound closure rates were determined using planimetric analysis. Wounds were biopsied and evaluated for histologic healing characteristics and cytokine mRNA expression. Days until wound closure was also determined. The results indicate that 3/6 of treatment horses and 1/6 of control horses experienced minor transient reactions. Treatment did not accelerate wound closure or improve histologic healing. Treatment decreased wound size and decreased all measured cytokines except transforming growth factor-β3. MSC intravenous therapy has the potential to decrease limb wound size; however, further work is needed to understand the clinical relevance of adverse reactions.

In vivo administration of G9a inhibitor A366 decreases osteogenic potential of bone marrow-derived mesenchymal stem cells

Epigenetic mechanisms such as histone methylation are considered as one of the most important mediators that control stem cell behaviors such as proliferation, senescence and differentiation. G9a, a histone methyltransferase, has recently generated intense attention as potential target for controlling many diseases such as cancers. The aim of the present study was to evaluate the effect of in vivo administration of A366, a G9a inhibitor, on proliferative and differentiation potential of bone marrow-derived mesenchymal stem cells (BM-MSCs). We inhibited G9a using intraperitoneally administration of A366, and we evaluated BM-MSC proliferation and differentiation behaviors in vitro. Colony formation assay of BM-MSCs at primary culture showed that in vivo administration of A366 reduced the colony forming capacity of BM-MSCs. Moreover, PDT of BM-MSC isolated from A366-treated rats was higher than control, especially in the early passages. BM-MSC isolated from A366-treated rats showed higher adipogenic potential compared to the control at the early passages as determined by gene expression and Oil Red staining. Whereas, osteogenic potential of BM-MSC isolated from A366-treated rats was lower than control, especially at early passages. Our results suggest that the epigenetic modifier such as A366, which seems to be a therapeutic approach for controlling diseases such as cancer, might also influence the proliferation and differentiation capacity of MSCs both in vitro and in vivo. Moreover, epigenetic modifying chemicals seem to be a strategy to manipulate MSC expansion capacity and differentiation propensity, as well as to efficiently involvement of MSCs in tissue homeostasis, cell-based therapy and tissue engineering.