Abstract
Bone marrow derived mesenchymal stem cells (BM-MSCs) have been shown to enhance wound healing; however, the mechanisms involved are barely understood. In this study, we examined paracrine factors released by BM-MSCs and their effects on the cells participating in wound healing compared to those released by dermal fibroblasts. Analyses of BM-MSCs with Real-Time PCR and of BM-MSC-conditioned medium by antibody-based protein array and ELISA indicated that BM-MSCs secreted distinctively different cytokines and chemokines, such as greater amounts of VEGF-α, IGF-1, EGF, keratinocyte growth factor, angiopoietin-1, stromal derived factor-1, macrophage inflammatory protein-1alpha and beta and erythropoietin, compared to dermal fibroblasts. These molecules are known to be important in normal wound healing. BM-MSC-conditioned medium significantly enhanced migration of macrophages, keratinocytes and endothelial cells and proliferation of keratinocytes and endothelial cells compared to fibroblast-conditioned medium. Moreover, in a mouse model of excisional wound healing, where concentrated BM-MSC-conditioned medium was applied, accelerated wound healing occurred compared to administration of pre-conditioned or fibroblast-conditioned medium. Analysis of cell suspensions derived from the wound by FACS showed that wounds treated with BM-MSC-conditioned medium had increased proportions of CD4/80-postive macrophages and Flk-1-, CD34- or c-kit-positive endothelial (progenitor) cells compared to wounds treated with pre-conditioned medium or fibroblast-conditioned medium. Consistent with the above findings, immunohistochemical analysis of wound sections showed that wounds treated with BM-MSC-conditioned medium had increased abundance of macrophages. Our results suggest that factors released by BM-MSCs recruit macrophages and endothelial lineage cells into the wound thus enhancing wound healing.
Highlights
Optimum healing of a cutaneous wound requires a wellorchestrated integration of the complex biological and molecular events of cell migration and proliferation, extracellular matrix (ECM) deposition, angiogenesis and remodeling [1,2,3]
To examine protein levels of cytokine released by Bone marrow derived mesenchymal stem cells (BM-MSCs) and dermal fibroblasts, we performed antibody-based protein array analysis of fibroblast- or MSC-conditioned medium under hypoxic or normoxic conditions, which reacted to 88 cytokines including 32 murine cytokines and 79 human cytokines (23 cytokines were redundant, Figure 2A and Table 3)
Fifteen cytokines at differential expression levels were found; of them 13 cytokines were apparently higher in BM-MSC-conditioned medium including EGF, KGF, IGF-1, glial cell line-derived neurotrophic factor (GDNF), platelet derived growth factor-BB (PDGF-BB), VEGF-a, Ang-1, EPO, TPO, macrophage inflammatory protein (MIP)-1, MIP-2, MCP-5 and soluble tumor necrosis factor receptor-1, and two cytokines were lower including IL6 and osteoprotegrin in BMMSC-conditioned medium, compared to fibroblast-conditioned medium (Figure 2A and Table 3)
Summary
Optimum healing of a cutaneous wound requires a wellorchestrated integration of the complex biological and molecular events of cell migration and proliferation, extracellular matrix (ECM) deposition, angiogenesis and remodeling [1,2,3]. As the major stromal cells in the bone marrow, BM-MSCs have been known to release factors such as erythropoietin (EPO) and granulocyte colonystimulating factor (G-CSF) supporting the survival, proliferation and differentiation of hematopoietic stem/progenitor cells. Many of these factors have recently been shown to enhance repair/regeneration of non-hematopoietic tissues [9,10]. Fibroblasts have been used clinically in patients to treat diabetic or venous skin ulcers, but the benefit remains controversial [11,12]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have