BackgroundHuman induced pluripotent stem cell-derived mesenchymal stem cells (hiPSC-MSCs) have emerged as a promising alternative for stem cell transplantation therapy. Exosomes derived from mesenchymal stem cells (MSC-Exos) can play important roles in repairing injured tissues. However, to date, no reports have demonstrated the use of hiPSC-MSC-Exos in cutaneous wound healing, and little is known regarding their underlying mechanisms in tissue repair.MethodshiPSC-MSC-Exos were injected subcutaneously around wound sites in a rat model and the efficacy of hiPSC-MSC-Exos was assessed by measuring wound closure areas, by histological and immunofluorescence examinations. We also evaluated the in vitro effects of hiPSC-MSC-Exos on both the proliferation and migration of human dermal fibroblasts and human umbilical vein endothelial cells (HUVECs) by cell-counting and scratch assays, respectively. The effects of exosomes on fibroblast collagen and elastin secretion were studied in enzyme-linked immunosorbent assays and quantitative reverse-transcriptase–polymerase chain reaction (qRT-PCR). In vitro capillary network formation was determined in tube-formation assays.ResultsTransplanting hiPSC-MSC-Exos to wound sites resulted in accelerated re-epithelialization, reduced scar widths, and the promotion of collagen maturity. Moreover, hiPSC-MSC-Exos not only promoted the generation of newly formed vessels, but also accelerated their maturation in wound sites. We found that hiPSC-MSC-Exos stimulated the proliferation and migration of human dermal fibroblasts and HUVECs in a dose-dependent manner in vitro. Similarly, Type I, III collagen and elastin secretion and mRNA expression by fibroblasts and tube formation by HUVECs were also increased with increasing hiPSC-MSC-Exos concentrations.ConclusionsOur findings suggest that hiPSC-MSC-Exos can facilitate cutaneous wound healing by promoting collagen synthesis and angiogenesis. These data provide the first evidence for the potential of hiPSC-MSC-Exos in treating cutaneous wounds.

Stem cells in human urine have gained attention in recent years; however, urine-derived stem cells (USCs) are far from being well elucidated. In this study, we compared the biological characteristics of USCs with adipose-derived stem cells (ASCs) and investigated whether USCs could serve as a potential cell source for neural tissue engineering. USCs were isolated from voided urine with a modified culture medium. Through a series of experiments, we examined the growth rate, surface antigens, and differentiation potential of USCs, and compared them with ASCs. USCs showed robust proliferation ability. After serial propagation, USCs retained normal karyotypes. Cell surface antigen expression of USCs was similar to ASCs. With lineage-specific induction factors, USCs could differentiate toward the osteogenic, chondrogenic, adipogenic, and neurogenic lineages. To assess the ability of USCs to survive, differentiate, and migrate, they were seeded onto hydrogel scaffold and transplanted into rat brain. The results showed that USCs were able to survive in the lesion site, migrate to other areas, and express proteins that were associated with neural phenotypes. The results of our study demonstrate that USCs possess similar biological characteristics with ASCs and have multilineage differentiation potential. Moreover USCs can differentiate to neuron-like cells in rat brain. The present study shows that USCs are a promising cell source for tissue engineering and regenerative medicine.

No abstract

Stimulating bone growth and regeneration, especially in patients with delayed union or non-union of bone, is a challenge for orthopaedic surgeons. Treatments employed for bone regeneration are based on the use of cells, biomaterials and factors. Among these therapies, cell treatment with mesenchymal stem cells (MSCs) has a number of advantages as MSCs: (1) are multipotent cells that can migrate to sites of injury; (2) are capable of suppressing the local immune response; and (3) are available in large quantities from the patients themselves. MSC therapies have been used for stimulating bone regeneration in animal models and in patients. Methods of application range from direct MSC injection, seeding MSCs on synthetic scaffolds, the use of gene-modified MSCs, and hetero-MSCs application. However, only a small number of these cell-based strategies are in clinical use, and none of these treatments has become the gold standard treatment for delayed or non-union of bone.