Clinicopathological Features and Immunohistochemical Alterations of Keratinocyte Proliferation, Melanocyte Density, Smooth Muscle Hyperplasia and Nerve Fiber Distribution in Becker's Nevus

BACKGROUND: Although Becker's nevus (BN) is a relatively common disease, the systematic studies of clinicopathological and immunohistochemical results are poorly reported. OBJECTIVE: To investigate the clinicopathological features and immunohistochemical alterations of keratinocyte proliferation, melanocyte density, smooth muscle hyperplasia and nerve fiber distribution in BN. METHODS: Clinical and pathological data were collected in 60 newly-diagnosed BN cases. Immunohistochemical stain of Ki-67, Melan-A, keratin 15, smooth muscle actin and protein gene product 9.5 was performed in 21 cases. RESULTS: The median diagnostic and onset age was 17 and 12 years, respectively. Skin lesions usually appeared on the upper trunk and upper limbs. The pathological features included the rete ridge elongation and fusion and basal hyperpigmentation. Epidermal Ki-67, Melan-A and keratin 15 expression and dermal nerve fiber length were significantly higher in lesional and perilesional skin than in normal skin (p<0.05~0.01), while smooth muscle actin expression was upregulated only in skin lesion (p<0.05). CONCLUSION: Although the clinical diagnosis of BN is often straightforward, histopathology is helpful to differentiate from other pigmentary disorders. The hyperproliferation of keratinocytes, melanocytes, arrector pili muscle and dermal nerve fibers could be involved in the pathogenesis of BN.

Effect of combination therapy with alginate dressing and mouse epidermal growth factor on epidermal stem cells in patients with refractory wounds / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The aim of this research was to determine the efficacy of combination therapy using an alginate dressing and mouse epidermal growth factor (mEGF) on proliferation and differentiation of epidermal stem cells (ESCs) in patients with refractory wounds.</p><p><b>METHODS</b>Eighteen patients (12 males and 6 females, aged from 18 to 61 years (mean 36.4 years)) with various skin wounds, were treated by dressing changing for one month. The wounds were located in the foot (11), calf (3), thigh (2) and forearm (2). The patients were randomly divided into 3 groups: alginate dressing and mEGF (group A; n = 6), mEGF (group B; n = 6) and control (group C; n = 6). Wound closure indexes were measured at 7, 14, 21 and 28 days. Samples were harvested for pathologic examination, at 7 and 14 days following treatment. Cytokeratin 10 (CK10) and cytokeratin 15 (CK15) positive cells were evaluated using the super-sensitivity (SP) immunohistochemical staining technique.</p><p><b>RESULTS</b>Wound healing was promoted in groups A and B. In group A, the wound closure index was increased significantly (P < 0.05), and in one case the maximum cure area reached 102 cm(2). Pathological examination identified a thicker epidermis, active angiogenesis and enhanced granulation in group A compared with groups B and C. Using the SP immunohistochemical staining technique, we showed that ESCs in group A were bigger in size and larger in number than in groups B and C. Overall, there was a significant difference in ESCs proliferation and differentiation between group A and group B (or C).</p><p><b>CONCLUSIONS</b>Combination therapy using an alginate dressing and mEGF shows increased proliferation and differentiation of ESCs in patients with refractory wounds compared with those treated with mEGF alone.</p>

Sox9 Increases the Proliferation and Colony-forming Activity of Outer Root Sheath Cells Cultured In Vitro

BACKGROUND: beta-catenin plays a pivotal role in hair follicle development and hair growth cycle. OBJECTIVE: The aim of this study was to identify beta-catenin-regulated genes in cultured human hair outer root sheath (ORS) cells. METHODS: Primary cultured ORS cells were transduced with recombinant adenovirus expressing N-terminal truncated beta-catenin (constitutive active form), and beta-catenin-regulated genes were identified. RESULTS: Overexpression of the constitutively active form of beta-catenin led to induction of Sox9 expression at both mRNA and protein levels. To investigate the potential role of Sox9, we made the recombinant adenovirus expressing green fluorescent protein-tagged Sox9, and then transduced into cultured ORS cells. Interestingly, Sox9 induced the expression of keratin 15, increased the proliferation of ORS cells in vitro, and enhanced colony-forming activity. CONCLUSION: Our results suggest that Sox9 is a beta-catenin-regulated gene in ORS cells, and has potential importance in the regulation of hair follicle homeostasis.

Immunohistochemical Expression of Stem Cell Markers during the Wound Healing Process of Cutaneous Burn

PURPOSE: A cutaneous wound healing requires a well-orchestrated integration of the complex biological and molecular events of cell migration and proliferation, extracellular matrix deposition, angiogenesis and remodeling. Finally, skin regeneration is the main goal. Stem cells are self-renewing multipotent progenitors with the broadest developmental potential in a given tissue at a given time. The aim of this study was to examine the role of stem cells during the wound healing process of cutaneous burn in hairless mice by using immunohistochemical stainings (nestin, cytokeratin 15 and CD31). METHODS: Each mouse received 2 burns at the dorsal area by applying a metal stick heated in boiling water. Burn wound sites were dressed with duoderm. The mice were sacrificed at 0, 2, 7, 14 and 21 days after burn. Histological findings and immunohistochemical expression for stem cell markers were observed. RESULTS: Nestin was expressed in the stromal cells beneath the epidermis, hair follices, dermal cysts and endothelial cells. Cytokeratin 15 was expressed in the epidermis except in basal cells. On 7 and 14 days after burn, the regenerated epidermis didn't express cytokeratin 15. CD31 was expressed in the endothelial cells on 7 and 14 days after burn. The amount of nestin expression was the highest. CONCLUSION: Our results showed that nestin may have various effects on burn wound healing. Cytokeratin 15 was expressed before burn and after burn. It is likely that other cytokeratin may stimulate epithelial regeneration. CD31 may act in vascular regeneration during burn healing.

In vitro culture of murine fetal epidermal stem cell and its relationship with the regeneration of follicle / 中华烧伤杂志

<p><b>OBJECTIVE</b>To isolate and culture the murine fetal epidermal stem cells (ESCs) and folliculus pili cells (FPCs) in vitro, and to observe the regeneration of hair follicle and epidermis after cografting of ESCs and FPCs.</p><p><b>METHODS</b>The ESCs were isolated by adhering to murine type IV collagen and were cultured in conditional medium. The expression level of beta1-integrin and keratin 15 in ESCs was detected. At the same time, the cell cycle and clony forming eficiency (CFE) in ESCs were also determined. The FPCs were isolated and cultured and inoculated in fibrin-gel to form FPCs-gel. A full skin equivalent was prepared by combining ESCs with FPCs-gel and was grafted onto total skin loss wounds on the back of BALB/C nude mice. The histological changes of the wounds and the hair follicles were observed at 8 - 10 weeks after the grafting.</p><p><b>RESULTS</b>There were high level expressions of beta1-integrin and keratin 15 in murine fetal ESCs. It was indicated by cell cycle analysis that cells in G1 stage accounted for 94.9% of the cells, while that in S stage, 3.5%, suggesting slow cell cycle. Nevertheless, the keratinocytes in G1 stage accounted for 74.1% and that in S stage, 17.5% of cells in control group. The CFE of ESCs was 15.3%, and it was much higher than that in control group (6.7%). The newly formed hair follicles could be found in the grafted rats but not in the control group 8 - 10 weeks after the wound healing in nude rats.</p><p><b>CONCLUSION</b>The ESCs could be successfully isolated and cultured in vitro and might participate in the formation of hair follicle structure under the induction of FPCs.</p>