Allogeneic mesenchymal stem cells improve the wound healing process of sheep skin.

BACKGROUND: Skin wound healing includes a system of biological processes, collectively restoring the integrity of the skin after injury. Healing by second intention refers to repair of large and deep wounds where the tissue edges cannot be approximated and substantial scarring is often observed. The objective of this study was to evaluate the effects of mesenchymal stem cells (MSCs) in second intention healing using a surgical wound model in sheep. MSCs are known to contribute to the inflammatory, proliferative, and remodeling phases of the skin regeneration process in rodent models, but data are lacking for large animal models. This study used three different approaches (clinical, histopathological, and molecular analysis) to assess the putative action of allogeneic MSCs at 15 and 42 days after lesion creation. RESULTS: At 15 days post-lesion, the wounds treated with MSCs showed a higher degree of wound closure, a higher percentage of re-epithelialization, proliferation, neovascularization and increased contraction in comparison to a control group. At 42 days, the wounds treated with MSCs had more mature and denser cutaneous adnexa compared to the control group. The MSCs-treated group showed an absence of inflammation and expression of CD3+ and CD20+. Moreover, the mRNA expression of hair-keratine (hKER) was observed in the MSCs-treated group 15 days after wound creation and had increased significantly by 42 days post-wound creation. Collagen1 gene (Col1α1) expression was also greater in the MSCs-treated group compared to the control group at both days 15 and 42. CONCLUSION: Peripheral blood-derived MSCs may improve the quality of wound healing both for superficial injuries and deep lesions. MSCs did not induce an inflammatory response and accelerated the appearance of granulation tissue, neovascularization, structural proteins, and skin adnexa.

Investigations of the corneal epithelium in Veterinary Medicine: State of the art on corneal stem cells found in different mammalian species and their putative application.

The existence of progenitor cells that can readily differentiate into a specific cell type is a common cellular strategy for physiological tissue growth and repair mechanisms. In the mammalian cornea, many aspects regarding the nature and location of these cells are still unclear. In the human limbus (peripheral area of the cornea) progenitor cells have been found and characterized but in non-human mammals, the picture is not so clear. In this review, we examine current knowledge about the morphology of limbus and the localization of corneal epithelial stem cells in all species studied so far, comparing data with humans. We have also explored different research directions in the veterinary field in order to discuss the: i) currently used protocols and ii) best range of treatments for ocular pathologies in which corneal stem cells are involved.