UNLABELLED: 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.

• Keywords
• Alkali-injured ocular surface, Corneal regeneration, Limbal stem cells, Mesenchymal stem cells, Stem cell-based therapy,
• MeSH
• Biomarkers metabolism   MeSH
• Cell- and Tissue-Based Therapy methods   MeSH
• Cell Differentiation MeSH
• Bone Marrow Cells cytology   physiology   MeSH
• Burns, Chemical pathology   therapy   MeSH
• Epithelial Cells cytology   physiology   transplantation   MeSH
• Gene Expression MeSH
• Neovascularization, Physiologic MeSH
• Rabbits MeSH
• Limbus Corneae blood supply   injuries   MeSH
• Mesenchymal Stem Cells cytology   physiology   MeSH
• Primary Cell Culture MeSH
• Cell Proliferation MeSH
• Re-Epithelialization physiology   MeSH
• Epithelium, Corneal blood supply   injuries   MeSH
• Tissue Scaffolds MeSH
• Mesenchymal Stem Cell Transplantation * MeSH
• Adipose Tissue cytology   physiology   MeSH
• Adipocytes cytology   physiology   MeSH
• Animals MeSH
• Check Tag
• Rabbits MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Biomarkers MeSH

Ocular surface defects represent one of the most common causes of impaired vision or even blindness. For treatment, keratoplasty represents the first choice. However, if corneal defects are more extensive and associated with a limbal stem cell (LSC) deficiency, corneal transplantation is not a sufficient therapeutic procedure and only viable approach to treatment is the transplantation of LSCs. When the LSC deficiency is a bilateral disorder, autologous LSCs are not available. The use of allogeneic LSCs requires strong immunosuppression, which leads to side-effects, and the treatment is not always effective. The alternative and perspective approach to the treatment of severe ocular surface injuries and LSC deficiency is offered by the transplantation of autologous mesenchymal stem cells (MSCs). These cells can be obtained from the bone marrow or adipose tissue of the particular patient, grow well in vitro and can be transferred, using an appropriate scaffold, onto the damaged ocular surface. Here they exert beneficial effects by possible direct differentiation into corneal epithelial cells, by immunomodulatory effects and by the production of numerous trophic and growth factors. Recent experiments utilizing the therapeutic properties of MSCs in animal models with a mechanically or chemically injured ocular surface have yielded promising results and demonstrated significant corneal regeneration, improved corneal transparency and a rapid healing process associated with the restoration of vision. The use of autologous MSCs thus represents a promising therapeutic approach and offers hope for patients with severe ocular surface injuries and LSC deficiency.

• MeSH
• Transplantation, Autologous MeSH
• Models, Biological MeSH
• Cell Differentiation MeSH
• Bone Marrow Cells cytology   metabolism   MeSH
• Antigens, CD metabolism   MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Mesenchymal Stem Cells cytology   metabolism   MeSH
• Intercellular Signaling Peptides and Proteins metabolism   MeSH
• Nanofibers * MeSH
• Corneal Diseases surgery   MeSH
• Cell Movement MeSH
• Stem Cell Transplantation methods   MeSH
• Mesenchymal Stem Cell Transplantation methods   MeSH
• Adipose Tissue cytology   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antigens, CD MeSH
• Intercellular Signaling Peptides and Proteins MeSH

Limbal stem cells (LSC), which reside in the basal layer of the limbus, are thought to be responsible for corneal epithelial healing after injury. When the cornea is damaged, LSC start to proliferate, differentiate, and migrate to the site of injury. To characterize the signaling molecules ensuring communication between the cornea and LSC, we established a mouse model of mechanical corneal damage. The central cornea or limbal tissue was excised at different time intervals after injury, and the expression of genes in the explants was determined. It was observed that a number of genes for growth and differentiation factors were significantly upregulated in the cornea rapidly after injury. The ability of these factors to regulate the differentiation and proliferation of limbal cells was tested. It was found that the insulin-like growth factor-I (IGF-I), which is rapidly overexpressed after injury, enhances the expression of IGF receptor in limbal cells and induces the differentiation of LSC into cells expressing the corneal cell marker, cytokeratin K12, without any effect on limbal cell proliferation. In contrast, the epidermal growth factor (EGF) and fibroblast growth factor-β (FGF-β), which are also produced by the damaged corneal epithelium, supported limbal cell proliferation without any effect on their differentiation. Other factors did not affect limbal cell differentiation or proliferation. Thus, IGF-I was identified as the main factor stimulating the expression of IGF receptors in limbal cells and inducing the differentiation of LSC into cells expressing corneal epithelial cell markers. The proliferation of these cells was supported by EGF and FGF.

• MeSH
• Cell Differentiation genetics   MeSH
• Epidermal Growth Factor biosynthesis   metabolism   MeSH
• Fibroblast Growth Factors biosynthesis   metabolism   MeSH
• Wound Healing physiology   MeSH
• Insulin-Like Growth Factor I biosynthesis   metabolism   MeSH
• Keratin-12 biosynthesis   MeSH
• Stem Cells metabolism   MeSH
• Limbus Corneae cytology   metabolism   MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• Cell Proliferation MeSH
• Receptor, IGF Type 1 biosynthesis   metabolism   MeSH
• Epithelium, Corneal * cytology   injuries   metabolism   MeSH
• Signal Transduction MeSH
• Gene Expression Profiling MeSH
• Up-Regulation MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Epidermal Growth Factor MeSH
• Fibroblast Growth Factors MeSH
• Insulin-Like Growth Factor I MeSH
• Keratin-12 MeSH
• Receptor, IGF Type 1 MeSH

Bone marrow-derived mesenchymal stem cells (MSCs) modulate immune response and can produce significant levels of transforming growth factor-β (TGF-β) and interleukin-6 (IL-6). These 2 cytokines represent the key factors that reciprocally regulate the development and polarization of naive T-cells into regulatory T-cell (Treg) population or proinflammatory T helper 17 (Th17) cells. In the present study we demonstrate that MSCs and their products effectively regulate expression of transcription factors Foxp3 and RORγt and control the development of Tregs and Th17 cells in a population of alloantigen-activated mouse spleen cells or purified CD4(+)CD25(-) T-cells. The immunomodulatory effects of MSCs were more pronounced when these cells were stimulated to secrete TGF-β alone or TGF-β together with IL-6. Unstimulated MSCs produce TGF-β, but not IL-6, and the production of TGF-β can be further enhanced by the anti-inflammatory cytokines IL-10 or TGF-β. In the presence of proinflammatory cytokines, MSCs secrete significant levels of IL-6, in addition to a spontaneous production of TGF-β. MSCs producing TGF-β induced preferentially expression of Foxp3 and activation of Tregs, whereas MSC supernatants containing TGF-β together with IL-6 supported RORγt expression and development of Th17 cells. The effects of MSC supernatants were blocked by the inclusion of neutralization monoclonal antibody anti-TGF-β or anti-IL-6 into the culture system. The results showed that MSCs represent important players that reciprocally regulate the development and differentiation of uncommitted naive T-cells into anti-inflammatory Foxp3(+) Tregs or proinflammatory RORγt(+) Th17 cell population and thereby can modulate autoimmune, immunopathological, and transplantation reactions.

• MeSH
• Cell Differentiation immunology   MeSH
• Cell Culture Techniques MeSH
• Cytokines biosynthesis   MeSH
• Immunity MeSH
• Culture Media, Conditioned pharmacology   MeSH
• Mesenchymal Stem Cells physiology   MeSH
• Mice MeSH
• Paracrine Communication immunology   MeSH
• T-Lymphocytes, Regulatory immunology   MeSH
• T-Lymphocytes immunology   MeSH
• Inflammation immunology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cytokines MeSH
• Culture Media, Conditioned MeSH