Sisi Yang

Controlled water vapor transmission rate promotes wound-healing via wound re-epithelialization and contraction enhancement

A desirable microenvironment is essential for wound healing, in which an ideal moisture content is one of the most important factors. The fundamental function and requirement for wound dressings is to keep the wound at an optimal moisture. Here, we prepared serial polyurethane (PU) membrane dressings with graded water vapor transmission rates (WVTRs), and the optimal WVTR of the dressing for wound healing was identified by both in vitro and in vivo studies. It was found that the dressing with a WVTR of 2028.3 ± 237.8 g/m2·24 h was able to maintain an optimal moisture content for the proliferation and regular function of epidermal cells and fibroblasts in a three-dimensional culture model. Moreover, the dressing with this optimal WTVR was found to be able to promote wound healing in a mouse skin wound model. Our finds may be helpful in the design of wound dressing for wound regeneration in the future.

A survey on the current status of burn rehabilitation services in China

BACKGROUND In China, there is a very long history of burn wound treatment, but the specialised burn care units were set up only from 1958. With more than 50 years of practice, great achievements have been made in burn wound care and operations in the country. However, in terms of burn rehabilitation, the development appears to be slow. In order to determine the current status of burn rehabilitation services in China, a survey was conducted to various burn centres in China. METHODS A comprehensive survey was conducted as well as to collect data related to (1) the admissions and staffing of the burn centres; (2) availability of rehabilitation services, number and educational background of specialised personnel dedicated in burn rehabilitation therapy; and (3) the difficulties leading to the lag of the burn rehabilitation services. The survey was sent to the chiefs of 87 burn centres via e-mail and they were requested to fill out the survey questionnaire and to send it back. For those who did not respond within 1 month, a reminder was sent. RESULTS There are totally 39 (44.8%) burn centres responding to our survey. These centres were geographically distributed in nearly 70% of the administrative provinces in China; hence, the results could well represent the current burn care system. Most centres have recognised the importance of rehabilitation therapy and remarkable improvements of outcome in burn patients have been achieved. There are a very huge number of burn patients that need rehabilitation therapy, but most centres face the problems of shortage of rehabilitation therapists, which apparently could lead to the difficulties in delivering a quality rehabilitation programme for patients. Although the time of rehabilitation therapy is instituted far earlier than before, it is still not widely accepted in the acute burn care stage. There are more specialists joining the burn centre and becoming members of the professional burn team. However, professional education and training in the burn specialty appear to be sparse. There is room for improvement. Problems that impede the progress of rehabilitation therapy are: lack of rehabilitation knowledge in medical staff as well as the public, the shortage of specialised personnel and relatively low educational background of this team, lack of standard guidelines for rehabilitation treatment instructions and lack of funding from the government. CONCLUSION After 20 years of clinical practice, rehabilitation concepts are well accepted and many forms of rehabilitation techniques are carried out in most burn centres that responded to the survey. Yet, the results also indicate that there is a short history of rehabilitation practice among the burn centres. There is a burning need to enhance the development of rehabilitation services so as to meet the demands of management of severely burned patients in China. Some suggestions are made to improve the current burn rehabilitation services which would include: (1) provide rehabilitation education programmes for burn surgeons, therapists, nurses, as well as patients, families and the public; (2) set up standard guidelines for clinical instruction of rehabilitation therapy; (3) build an interdisciplinary burn team; (4) more investigation and research on the physical and psychological outcomes of burn patients; and (5) implement administrative measures in terms of staffing, funding and offering insurance to burn survivors.

Nitric Oxide Enhances Keratinocyte Cell Migration by Regulating Rho GTPase via cGMP-PKG Signalling

Objective Nitric oxide (NO) has been shown to improve wound healing, but the mechanism underlying this function is not well defined. Here, we explored the effect of NO on the migration of a human keratinocyte cell line (HaCaT) and its possible mechanism. Methods The effects of NO on HaCaT cells in the presence of different concentrations of the NO donor sodium nitroprusside (SNP) were evaluated in a cell migration assay. Subsequently, the cytoskeleton reorganization of cultured HaCaT cells stained with rhodamine-phalloidin was observed with a confocal laser scanning microscope. The mRNA expression and active proteins of CDC42, Rac1 and RhoA in the cultured cells were determined via RT-PCR and pull-down assays, respectively. Furthermore, the roles of various inhibitors or agonists specific to cGMP, PKG and CDC42, Rac1, RhoA in the effects of NO on HaCaT cell migration, F-actin stress fibre formation, and Rho GTPase expression were observed. Results It was also found HaCaT cell migration was increased by SNP in a dose-dependent manner, and the other two NO donors either spermine NONOate or SNAP had almost the same effects on HaCat cell migrations. The formation of F-actin stress fibres in SNP-treated HaCaT cells was increased. The mRNA expression and the active proteins of CDC42, Rac1 and RhoA were found to be upregulated after SNP treatment. Similar effects were observed after the cells were treated with a cGMP or PKG agonist. Additionally, the SNP-mediated upregulation of the mRNA expression and the active proteins of CDC42, Rac1 and RhoA were inhibited by the addition of an inhibitor of cGMP or PKG. Moreover, the SNP-mediated promoting effects of migration and cytoskeleton reorganization were inhibited by treatment with inhibitors of cGMP, PKG, CDC42, Rac1 and RhoA respectively. Conclusion Our data indicated that the stimulatory effects of NO on cell migration of HaCaT cells are mediated by the cGMP signalling pathway via the upregulation of Rho-GTPase expression, which might promote cytoskeleton reorganization.

P311 promotes renal fibrosis via TGFβ1/Smad signaling

P311, a gene that was identified in 1993, has been found to have diverse biological functions in processes such as cell proliferation, migration and differentiation. However, its role in fibrosis is unknown. We previously observed that P311 is highly expressed in skin hypertrophic scars. In this study, P311 over-expression was detected in a subset of tubular epithelial cells in clinical biopsy specimens of renal fibrosis; this over-expression, was found concurrent with α-smooth muscle actin (α-SMA) and transforming growth factor beta1 (TGFβ1) expression. Subsequently, these results were verified in a mouse experimental renal fibrosis model induced by unilateral ureteral obstruction. The interstitial deposition of collagen, α-SMA and TGF-β1 expression, and macrophage infiltration were dramatically decreased when P311 was knocked out. Moreover, TGFβ/Smad signaling had a critical effect on the promotion of renal fibrosis by P311. In conclusion, this study demonstrate that P311 plays a key role in renal fibrosis via TGFβ1/Smad signaling, which could be a novel target for the management of renal fibrosis.

CD86 Is an Activation Receptor for NK Cell Cytotoxicity against Tumor Cells

CTLA4Ig has been successfully used in the clinic for suppression of T cell activation. However, patients treated with CTLA4Ig experienced reduced incidence of tumors than predicted, but the underlying mechanism remains unknown. In this paper, we showed that brief administration of CTLA4Ig significantly reduced tumor metastasis and prolonged the survival of host mice bearing B16 melanoma. Depletion of NK cells prior to CTLA4Ig administration eliminated the CTLA4Ig-mediated anti-tumor activity. CTLA4Ig enhanced NK cell cytotoxicity to tumor cells via up-regulation of NK cell effecter molecules CD107a and perforin in vivo. In addition, we demonstrated that, upon activation, NK cells could significantly increase the expression of CD86 both in vitro and in vivo, and ligation of CD86 with CTLA4Ig significantly increased the ability of NK cells to kill tumor cells. Furthermore, a human NK cell line that expressed high level of CD86 was directly activated by CTLA4Ig so that killing of tumor targets was enhanced; this enhanced killing could be inhibited by blocking CD86. Our findings uncover a novel function of CTLA4Ig in tumor immunity and suggest that CD86 on NK cells is an activating receptor and closely involved in the CTLA4Ig-mediated anti-tumor response.

Three-Dimensional Histological Structures of the Human Dermis.

Spatial information has been shown to be critical for cell differentiation and function. Therefore, a better understanding of skin microstructures is very important for biomimetic and bioengineered scaffolds of engineering skin. The purpose of the study was to generate collagen/elastin-based three-dimensional (3D) images of human dermis to further understand the microstructures of the skin, which is believed to be helpful in the fabrication of bionic engineered skin. Skin samples were fixed, embedded, serially sectioned, stained with aldehyde-fuchsin, and photographed as serial panoramas. Dermal subregions were divided according to dermal depth and distance to hair follicle. The porosity, pore diameters, and wall thickness of human acellular dermal matrix (ADM) were measured by microcomputed tomography (micro-CT). Three-dimensional reconstructed images of collagen and elastic fibers were generated. Our results showed that there were fewer elastic fibers in the subregions close to hair follicles than in the subregions far away from hair follicles (p<0.001), but the collagen fibers were evenly distributed. Both collagen and elastic fibers were found in fewer numbers in the layers either close to the epidermis or close to the hypodermis. The mean proportions of collagen fibers and elastic fibers in the whole dermis were 28.96%±14.63% and 8.06%±3.75%, respectively. The porosity of ADM calculated by micro-CT was 68.3%±5.8%. The mean pore diameter of ADM was 131.2±96.8 μm, and the wall thickness of pores was 207.2±251.7 μm. This study represents for the first time that 3D histological cutaneous structures have been presented, which may be helpful for the next generation of skin engineering.

Blood loss during extensive escharectomy and auto-microskin grafting in adult male major burn patients.

PURPOSE To improve the accuracy of blood loss estimation during extensive escharectomy and auto-microskin grafting on extremities in adult male major burn patients. METHOD All adult male major burn patients admitted to our center who underwent extensive escharectomy and auto-microskin graft on extremities for more than 10% TBSA during the period 1 January 2008 to 31 December 2009 were involved in this study. The blood loss during the operation was estimated by the surgeons or calculated according to the changes in hemoglobin levels. RESULTS The average burn and escharectomy areas for the 64 burn patients included in the study were 74.16 ± 16.96% and 30.27 ± 15.63% TBSA respectively. The auto-microskin donor area was 3.81% TBSA. The volumes of intra-operative calculated and estimated blood losses and transfused blood during the operation were 0.47 ml/cm2, 0.13 ml/cm2 and 0.20 ml/cm2 surgical area 77.29 ml, 20.51 ml and 32.83 ml per 1% TBSA), respectively. Within two weeks after injury surgical blood loss appeared to be greater the later the operation was carried out. Within the first week after injury the mean proportional blood loss was increased with area excised. CONCLUSION In this study the average calculated blood loss for the operation of extensive escharectomy and microskin graft in adult male major burn patient was 0.47 ml/cm2 (77.29 ml per 1% TBSA). This result will help us to predict expected blood loss more accurately.

Process of Hypertrophic Scar Formation: Expression of Eukaryotic Initiation Factor 6.

Background: Hypertrophic scar is one of the most common complications and often causes the disfigurement or deformity in burn or trauma patients. Therapeutic methods on hypertrophic scar treatment have limitations due to the poor understanding of mechanisms of hypertrophic scar formation. To throw light on the molecular mechanism of hypertrophic scar formation will definitely improve the outcome of the treatment. This study aimed to illustrate the negative role of eukaryotic initiation factor 6 (eIF6) in the process of human hypertrophic scar formation, and provide a possible indicator of hypertrophic scar treatment and a potential target molecule for hypertrophic scar. Methods: In the present study, we investigated the protein expression of eIF6 in the human hypertrophic scar of different periods by immunohistochemistry and Western blot analysis. Results: In the hypertrophic scar tissue, eIF6 expression was significantly decreased and absent in the basal layer of epidermis in the early period, and increased slowly and began to appear in the basal layer of epidermis by the scar formation time. Conclusions: This study confirmed that eIF6 expression was significantly related to the development of hypertrophic scar, and the eIF6 may be a target molecule for hypertrophic scar control or could be an indicator of the outcomes for other treatment modalities.

Identification of ITGB4BP as a new interaction protein of P311

AIMS P311 is an 8 kDa protein that has been shown to be of importance in the process of myofibroblast transformation, glioblastoma invasion and nerve regeneration. However, the interaction protein of P311 has yet to be found. The purpose of this study was to find the interactive protein of P311. MAIN METHODS The yeast two-hybrid system was used for screening the potential interaction proteins of P311. Joint expression of the potential interactive protein and P311 was immunohistochemically stained. The interaction between P311 and the selected protein was further confirmed by fluorescence resonance energy transfer (FRET) in pulmonary adenocarcinoma tissue sections, and by coimmunoprecipitation in HEK293. KEY FINDINGS Integrin β4 binding protein (ITGB4BP) was confirmed as the interaction protein of P311. Co-expression and interaction of ITGB4BP and P311 were demonstrated in pulmonary adenocarcinoma by both immunohistochemistry and FRET. Moreover the interaction between P311 and ITGB4BP was demonstrated by coimmunoprecipitation in HEK293. SIGNIFICANCE The interactions between P311 and ITGB4BP may be very important in the process of tumor cell differentiation and metastasis. ITGB4BP may provide a potential new target for the therapy of tumors.

P311 induces the transdifferentiation of epidermal stem cells to myofibroblast-like cells by stimulating transforming growth factor β1 expression

BackgroundEpithelial to mesenchymal transition, especially to myofibroblasts, plays an important role in wound healing, fibrosis, and carcinogenesis. Epidermal stem cells (EpSCs) are responsible for epidermal renewal and wound re-epithelialization. However, it remains unclear whether and how EpSCs transdifferentiate into myofibroblasts or myofibroblast-like cells (MFLCs). Here, we provide the first evidence showing that P311 induces EpSC to MFLC transdifferentiation (EpMyT) via TGFβ1/Smad signaling.MethodsWound healing and mesenchymal features were observed in the P311 KO and P311 WT mouse model of superficial second-degree burns. After the primary human or mouse EpSCs were forced to highly express P311 using an adenoviral vector, EpMyT was observed by immunofluorescence, real-time PCR, and western blot. The activity of TGFβ1 and Smad2/3 in EpSCs with different P311 levels was observed by western blot. The TβRI/II inhibitor LY2109761 and Smad3 siRNA were applied to block the EpMyT in P311-overexpressing EpSCs and exogenous TGFβ1 was to restore the EpMyT in P311 KO EpSCs. Furthermore, the mechanism of P311 regulating TGFβ1 was investigated by bisulfite sequencing PCR, luciferase activity assay, and real-time PCR.ResultsP311 KO mouse wounds showed delayed re-epithelialization and reduced mesenchymal features. The human or mouse EpSCs with overexpressed P311 exhibited fusiform morphological changes, upregulated expression of myofibroblast markers (α-SMA and vimentin), and downregulated expression of EpSC markers (β1-integrin and E-cadherin). P311-expressing EpSCs showed decreased TGFβ1 mRNA and increased TGFβ1 protein, TβRI/II mRNA, and activated Smad2/3. Moreover, LY2109761 and Smad3 siRNA reversed P311-induced EpMyT. Under the stimulation of exogenous TGFβ1, the phosphorylation of Smad2 and Smad3 in P311 KO EpSCs was significantly lower than that in P311 WT EpSCs and the EpMyT in P311 KO EpSCs was restored. Furthermore, P311 enhanced the methylation of TGFβ1 promoter and increased activities of TGFβ1 5′/3′ untranslated regions (UTRs) to stimulate TGFβ1 expression. P311+α-SMA+ cells and P311+vimentin+ cells were observed in the epidermis of human burn wounds. Also, P311 was upregulated by IL-1β, IL-6, TNFα, and hypoxia.ConclusionsP311 is a novel TGFβ1/Smad signaling-mediated regulator of transdifferentiation in EpSCs during cutaneous wound healing. Furthermore, P311 might stimulate TGFβ1 expression by promoting TGFβ1 promoter methylation and by activating the TGFβ1 5′/3′ UTR.