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PubMed | The First Peoples Hospital of Foshan Foshan and Sun Yat Sen University
Type: Journal Article | Journal: International journal of clinical and experimental pathology | Year: 2014

Hypertrophic scars are fibroproliferative disorders of excessive wound healing after skin injury. Vascular endothelial growth factor (VEGF)-induced angiogenesis plays a major role in fibrogenesis and hypertrophic scar formation. Over recent years, there has been a major interest in homeobox gene regulation of VEGF-VEGFR mediated angiogenesis in dermal tissue. In the current study, we investigated the role of homeobox genes in the epidermis, for their role in angiogenesis, with a focus on epidermal-mesenchymal interactions. As epidermal stem cells (ESCs) have a central role in epidermal homeostasis, we tested the hypothesis that these cells play a key role in the pathogenesis of hypertrophic scars through the HOXA9-VEGF/VEGFR signaling pathways. We found significant differences in the expression of homeobox A9 in hyperplastic scar tissue during different phases of development. These differences coincided with similar regulations in VEGF expression and with the distribution of ESCs. HOXA9 is expressed in cultured human ESCs in vitro. Antisense suppression of HOXA9 expression was found to suppress VEGF levels in ESCs. Together these findings indicate that homeobox A9 regulates the expression of VEGF in ESCs.


PubMed | The First Peoples Hospital of Foshan Foshan
Type: Journal Article | Journal: International journal of clinical and experimental pathology | Year: 2013

The management of burns and injuries using novel treatment strategies involving epidermal stem cells (ESC) requires a better understanding of the biology of these cells, in particular, their isolation and the maintenance of their unique characteristics in culture. The purpose of this study was to describe an improved method for isolating putative ESC from fetal rat skin and to maintain them long term in culture. Single ESC suspensions were obtained from fetal rat skin by enzyme digestion containing 0.5% neutral protease. The target cells were harvested by rapid adherence on type IV collagen plates and were cultured in complex DMEM. After primary isolation, cells were continuously cultured in K-serum free medium. After reaching 70-80% confluence, the cells were digested with 0.25% trypsin at 37C for 5-10 minutes, and passaged at a ratio of 1:2. The cultured ESC showed good growth, resulting in cell viability of over 98%. Four days later, clones containing 100-200 cells were detected, showing cobblestone-like characteristics. The rapidly adherent cells were positive for keratin 15, 19 and P63. Eighty three percent of cells expressed 1 integrin. The growth-curve showed that the rapidly adherent cells were in the exponential growth phase. The protocol described in this paper provides a simplified and effective method to isolate and maintain long-term culture of epidermal stem cells from fetal rat skin. This method should be valuable for isolating and studying ESC from various transgenic rat lines that are currently available.

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