Hair follicle stem cells promote cutaneous wound healing through the SDF-1α/CXCR4 axis: an animal model.

OBJECTIVE: An appropriate source of adult stem cells for therapeutic use is stem cells deriving from the hair follicle bulge. Following injury, ischaemic tissues produce a variety of cytokines and growth factors that are essential for tissue repair. This study sought to investigate the temporal effects of hair follicle bulge stem cells (HFSCs) on cutaneous wound healing in rats using the SDF-1α/CXCR4 axis. METHOD: HFSCs obtained from rat vibrissa, labeled with DiI and then special markers, were detected using flow cytometry. The animals were divided into five groups: control (non-treated, n=18), sham (PBS, n=18), AMD (treated with AMD3100, n=18), HFSC + AMD (treated with HFSCs + AMD3100, n=18) and HFSC (treated with HFSCs, n=18). A full-thickness excisional wound model was created and DiI-labeled HFSCs were injected around the wound bed. Wound healing was recorded with digital photographs. The animals were sacrificed 3, 7 and 14 days after the surgery and were used for histological (H&E, Masson's trichrome staining) and molecular (ELISA and q-PCR) assays. RESULTS: The flow cytometry results demonstrated that HFSCs were CD34-positive, nestin-positive, but Kr15-negative. The morphological analysis of the HFSC-treated wounds showed accelerated wound closure. The histological analysis of the photomicrographs exhibited more re-epithelialisation and dermal structural regeneration in the HFSC-treated wounds compared with the control group. In the HFSC + AMD group, the histological parameters improved on the same days, but showed a significant decrease compared with the HFSC group in all the days assayed. In the AMD group, there was a significant reduction in the noted parameters. qRT-PCR and ELISA showed a high expression level of SDF-1α, CXCR4 and VEGFR-2 in the HFSC-treated wounded skin tissue, but the expression of CXCR4 and VEGFR-2 showed a significant reduction in the HFSC + AMD group compared with the HFSC group. CONCLUSIONS: Based on the findings of this study, HFSC transplantation affects wound closure parameters and the expression of SDF-1α and CXCR4. As the SDF-1α expression level increases in the injured area, the HFSCs contribute to wound repair through the SDF-1α/CXCR4 axis. This result is extremely valuable because it raises the possibility of wounds healed by isolating autologous HFSCs from the patient.

The role of biodegradable engineered random polycaprolactone nanofiber scaffolds seeded with nestin-positive hair follicle stem cells for tissue engineering.

BACKGROUND: Tissue engineering is a new approach to reconstruction and/or regeneration of lost or damaged tissue. The purpose of this study was to fabricate the polycaprolactone (PCL) random nanofiber scaffold as well as evaluation of the cell viability, adhesion, and proliferation of rat nestin-positive hair follicle stem cells (HFSCs) in the graft material using electrospun PCL nanofiber scaffold in regeneration medicine. MATERIALS AND METHODS: The bulge HFSCs was isolated from rat whiskers and cultivated in Dulbecco's modified Eagle's medium/F12. To evaluate the biological nature of the bulge stem cells, flow cytometry using nestin, CD34 and K15 antibodies was performed. Electrospinning was used for the production of PCL nanofiber scaffolds. Furthermore, scanning electron microscopy (SEM) for HFSCs attachment, infiltration, and morphology, 3-(4, 5-di-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay for cell viability and cytotoxicity, tensile strength of the scaffolds mesh, and histology analysis were used. RESULTS: Flow cytometry showed that HFSCs were nestin and CD34 positive but K15 negative. The results of the MTT assay showed cell viability and cell proliferation of the HFSCs on PCL nanofiber scaffolds. SEM microscopy photographs indicated that HFSCs are attached and spread on PCL nanofiber scaffolds. Furthermore, tensile strength of the scaffolds mesh was measured. CONCLUSION: The results of this study revealed that modified PCL nanofiber scaffolds are suitable for HFSCs seeding, attachment, and proliferation. Furthermore, HFSCs are attached and proliferated on PCL nanofiber scaffolds.