Continue to promote the construction of the discipline system of wound repair with Chinese characteristics / 中华烧伤杂志

The repair of various kinds of complex and difficult-to-heal wounds is a major national demand for disease treatment in new era. Since the National Health Commission approved the establishment of wound repair departments in medical institutions with suitable condition at all levels in 2019, remarkable achievement has been achieved in the construction of the discipline system of wound repair in China in the past 3 years. In this paper, I would like to summarize the fruitful achievements in the field of wound repair in China in the past 3 years and put forward some suggestions for the next development of the discipline.

Effect of human decidua mesenchymal stem cells-derived exosomes on the function of high glucose-induced senescent human dermal fibroblasts and its possible mechanism / 中华烧伤杂志

Objective: To establish a high glucose senescent model of human dermal fibroblasts (HDFs), and to investigate the effects of exosomes derived from human decidua mesenchymal stem cells (dMSCs) on the proliferation, migration, and apoptosis of senescent HDFs and possible mechanism. Methods: The experimental research method was used. From January to March 2021, discarded foreskin tissue was collected for isolation and culture of primary HDFs from 4 male phimosis patients (aged 18-22 years) admitted for circumcision in the Fourth Medical Center of the PLA General Hospital. The 6th passage of HDFs were taken and divided into low glucose group and high glucose group according to the random number table, and subsequently cultured in low-glucose complete medium and high-glucose complete medium, respectively, with medium changed every 72 h without subculturing. After 10 days of culture, the cells were taken and measured for cellular senescence using the β-galactosidase kit at 24 h after seeding; the expression of senescence-related proteins p16 and p53 was assessed by Western blotting at 48 h after seeding; cell proliferation was detected at 24, 48, and 72 h after seeding using the cell counting kit 8 (CCK-8) method; the cell proliferation was evaluated by 5-ethynyl-2'-deoxyuridine (EdU) staining method, cell cycle and apoptosis were measured by flow cytometry after 48 h of seeding; Transwell experiment was used for the calculation of cell migration rate at 24 h after seeding. The human dMSCs were taken and cultured for 48-72 h from which the exosomes were extracted by differential high speed centrifugal method. The morphology of dMSC exosomes was observed by transmission electron microscopy, the particle size distribution of dMSC exosomes was measured by nanoparticle tracking analysis, and the expression of dMSC-exosomes marker proteins CD9 and tumor susceptibility gene101 (TSG101) were detected by Western blotting. The dMSC exosomes and high-glucose complete medium-induced senescent HDFs were co-cultured for 24 hours, then PKH67 kit was used to detect the uptake of exosomes by HDFs. High-glucose complete medium-induced senescent HDFs were taken and divided into high glucose alone group, high glucose+low concentration of exosomes group, and high glucose+high concentration of exosomes group according to the same method above. The high-glucose complete medium with equal volume of phosphate buffered saline, dMSC exosomes with final concentration of 50 μg/mL, and dMSC exosomes with final concentration of 100 μg/mL were added to the corresponding groups for conventional cell culture, respectively. After grouped, the cell proliferation, cell cycle and apoptosis as well as cell migration were detected by CCK-8 method and EdU staining method, flow cytometry, and Transwell experiment at the corresponding time points as before, respectively. Based on the previous results, high-glucose complete medium-induced senescent HDFs were taken and divided into high glucose alone group and high glucose+high concentration of exosomes group for the same treatment. After being grouped and cultured for 48 h, real-time fluorescent quantitative polymerase chain reaction was used to evaluate the mRNA expression of senescent-related microRNA (miR)-145-5p, miR-498, miR-503-5p, calcium/calmodulin dependent protein kinase 1D (CAMK1D), phosphates and tensin homologue deleted on chromosome ten (PTEN) gene, and Cyclin D1 in high glucose alone group and high glucose+high concentration of exosomes group. Data were statistically analyzed with analysis of variance for factorial design, one-way analysis of variance, least significant difference t test, and independent sample t test. Results: At 24 h after seeding, the rate of β-galactosidase-positive staining of HDF in high glucose group was (38.4±4.2)%, which was significantly higher than (16.5±2.2)% of low glucose group (t=4.65, P<0.01). At 48 h after seeding, the expression levels of senescence-related proteins p16 and p53 both were significantly higher in HDFs of high glucose group than those in low glucose group (with t values of 11.85 and 3.02, respectively, P<0.05 or P<0.01). At 0, 24, 48, and 72 h after seeding, the cell proliferation viability of HDFs in high glucose group was all significantly lower than in low glucose group (with t values of 4.13, 9.90, and 15.12, respectively, P<0.01). At 48 h after seeding, the rate of EdU-positive staining of HDFs in high glucose group was obviously lower than that of low glucose group (t=3.83, P<0.05). At 48 h after seeding, the percentage of G2/M+S subpopulations in three subpopulations (G0/G1, S, and G2/M) of HDF cycle was significantly lower in high glucose group than that in low glucose group (t=8.74, P<0.01). At 24 h after seeding, the number of HDFs migrated through the filter membrane to the lower chamber was 37±6 in high glucose group, which was significantly less than 74±7 in low glucose group (t=8.42, P<0.01). At 48 h after seeding, the HDF apoptosis rate was significantly higher in high glucose group than in low glucose group (t=8.48, P<0.01). The dMSC exosomes were cup-shaped or round vesicles with well-defined edges and uniform size distribution. The size of dMSC exosomes was basically in the range of 80-200 nm. Exosomal markers including CD9 and TSG101 were positively presented on the dMSC exosomes. After being co-cultured for 24 hours, the dMSC exosomes were taken up intracellularly by HDFs and mainly distributed around the nucleus of HDFs. After being grouped and cultured for 24, 48, and 72 h, the HDF proliferation viabilities in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly higher than in high glucose alone group (with t values of 6.36, 6.10, 7.76, 8.92, 12.17, and 10.74, respectively, P<0.01), the HDF proliferation viability in high glucose+high concentration of exosomes group was significantly higher than in high glucose+low concentration of exosomes group (with t values of 7.92, 4.82, and 4.72, respectively, P<0.01). After being grouped and cultured for 48 h, the percentages of EdU-positive HDFs in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly higher than in high glucose alone group (with t values of 5.32 and 9.88, respectively, P<0.01), the percentage of EdU-positive HDFs in high glucose+high concentration of exosomes group was notably higher than in high glucose+low concentration of exosomes group (t=5.27, P<0.01). After being grouped and cultured for 48 h, the proportion of G0/G1 subpopulation in both high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group was distinctly lower (with t values of 3.81 and 4.31, respectively, P<0.05), while the proportion of G2/M+S subpopulation was markedly higher (with t values of 3.81, 4.31, respectively, P<0.05) than in high glucose alone group. After being grouped and cultured for 24 h, the number of HDFs migrated through the filter membrane in both high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group was significantly higher than in high glucose alone group (with t values of 10.14 and 13.39, respectively, P<0.01), the number of HDFs migrated through the filter membrane in high glucose+high concentration of exosomes group was significantly increased than in high glucose+low concentration of exosomes group (t=6.27, P<0.01). After being grouped and cultured for 48 h, the HDF apoptosis rates in high glucose+low concentration of exosomes group and high glucose+high concentration of exosomes group were both significantly lower than in high glucose alone group (with t values of 3.72 and 5.53, respectively, P<0.05 or P<0.01). After being grouped and cultured for 48 h, compared with those in high glucose alone group, the mRNA expression levels of miR-145-5p and miR-498 were both obviously higher (with t values of 13.03 and 8.90, respectively, P<0.01), while the mRNA expression level of miR-503-5p was significantly lower (t=3.85, P<0.05) in high glucose+high concentration of exosomes group. After being grouped and cultured for 48 h, compared with those in high glucose alone group, the mRNA expression levels of CAMK1D and PTEN gene were both significantly lower (with t values of 8.83 and 5.97, respectively, P<0.01), while the mRNA expression level of Cyclin D1 was significantly higher in high glucose+high concentration of exosomes group (t=4.03, P<0.05). Conclusions: The dMSC exosomes are capable of improving cell proliferation and migration, and inhibiting cell apoptosis of high-glucose senescent HDFs. This may be related to the mechanism by which the increased expressions of intracellular miR-145-5p and miR-498 inhibit the expression of CAMK1D and PTEN gene, and the decreased expression of miR-503-5p promote the expression of Cyclin D1.

Establishment of "Chinese way" for trauma and burn management based on the engineered growth factors research and application / 中华烧伤杂志

Innovation and translation application are important topics that have been discussed repeatedly in national community of science and technology in recent years. We do a systemic review about the research and development history of growth factors, their application in trauma and burn management in China, and the conception and experience about the establishment of "Chinese way" for trauma and burn management in the process of constructing a disciplinary system for wound treatment with Chinese characteristics. It is our hope that these precious experiences will provide references and inspiration to our peers, especially the young generation in their research.

Application of limiting antigen avidity enzyme immunoassay for estimating HIV-1 incidence in men who have sex with men / 中华流行病学杂志

Objective: To estimate the incidence of HIV-1 infection in men who have sex with men (MSM) in key areas of China through HIV-1 limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA), analyze the deviation from the actual results and identify influencing factors, and provided reference for improving the accuracy of estimation results. Methods: Based on the principle of the cohort randomized study design, 20 cities were selected in China based on population size and the number of HIV-positive MSM. The sample size was estimated to be 700 according to the HIV-1 infection rate in MSM. MSM mobile phone app. was used to establish a detection appointment and questionnaire system, and the baseline cross-sectional survey was conducted from April to November 2019. LAg-Avidity EIA was used to identify the recent infected samples. The incidence of HIV-1 infection was calculated and then adjusted based on the estimation formula designed by WHO. The influencing factors were identified by analyzing the sample collection and detection processes. Results: Among the 10 650 blood samples from the participants, 799 were HIV-positive in initial screening, in which 198 samples (24.78%) missed during confirmation test. Only 621 samples were received by the laboratory. After excluding misreported samples, 520 samples were qualified for testing. A total of 155 samples were eventually determined as recent infection through LAg-Avidity EIA; Based on the estimation formula , the incidence of HIV-1 infection in MSM in 20 cities was 4.06% (95%CI:3.27%-4.85%), it increased to 5.53% (95%CI: 4.45%-6.60%)after the adjusting for sample missing rate. When the sample missing rate and misreporting rate were both adjusted, the incidence of HIV-1 infection in the MSM increased to 5.66% (95%CI:4.67%-6.65%). The actual incidence of HIV-1 infection in MSM in the 20 cities might be between 4.06% and 5.66%. Conclusions: Sample missing and misreporting might cause the deviation of the estimation of HIV-1 infection incidence. It is important to ensure the sample source and the quality of sample collection and detection to reduce the deviation in the estimation of HIV-1 infection incidence.

Effects of in situ cross-linked graphene oxide-containing gelatin methacrylate anhydride hydrogel on wound vascularization of full-thickness skin defect in mice / 中华烧伤杂志

Objective: To prepare graphene oxide (GO)-containing gelatin methacrylate anhydride (GelMA) hydrogel and to investigate the effects of in situ photopolymerized GO-GelMA composite hydrogel in wound vascularization of full-thickness skin defect in mice. Methods: The experimental study method was used. The 50 μL of 0.2 mg/mL GO solution was evenly applied onto the conductive gel, and the structure and size of GO were observed under field emission scanning electron microscope after drying. Human skin fibroblasts (HSFs) were divided into 0 μg/mL GO (without GO solution, the same as below) group, 0.1 μg/mL GO group, 1.0 μg/mL GO group, 5.0 μg/mL GO group, and 10.0 μg/mL GO group treated with GO of the corresponding final mass concentration, and the absorbance value was detected using a microplate analyzer after 48 h of culture to reflect the proliferation activity of cells (n=6). HSFs and human umbilical vein vascular endothelial cells (HUVECs) were divided into 0 μg/mL GO group, 0.1 μg/mL GO group, 1.0 μg/mL GO group, and 5.0 μg/mL GO group treated with GO of the corresponding final mass concentration, and the migration rates of HSFs at 24 and 36 h after scratching (n=5) and HUVECs at 12 h after scratching (n=3) were detected by scratch test, and the level of vascular endothelial growth factor (VEGF) secreted by HSFs after 4, 6, and 8 h of culture was detected by enzyme-linked immunosorbent assay method (n=3). The prepared GO-GelMA composite hydrogels containing GO of the corresponding final mass concentration were set as 0 μg/mL GO composite hydrogel group, 0.1 μg/mL GO composite hydrogel group, 1.0 μg/mL GO composite hydrogel group, and 5.0 μg/mL GO composite hydrogel group to observe their properties before and after cross-linking, and to detect the release of GO after soaking with phosphate buffer solution for 3 and 7 d (n=3). The full-thickness skin defect wounds were made on the back of 16 6-week-old female C57BL/6 mice. The mice treated with in situ cross-linked GO-GelMA composite hydrogel containing GO of the corresponding final mass concentration were divided into 0 μg/mL GO composite hydrogel group, 0.1 μg/mL GO composite hydrogel group, 1.0 μg/mL GO composite hydrogel group, and 5.0 μg/mL GO composite hydrogel group according to the random number table, with 4 mice in each group. The general condition of wound was observed and the wound healing rate was calculated on 3, 7, and 14 d of treatment, the wound blood perfusion was detected by laser Doppler flowmetry on 3, 7, and 14 d of treatment and the mean perfusion unit (MPU) ratio was calculated, and the wound vascularization on 7 d of treatment was observed after hematoxylin-eosin staining and the vascular density was calculated (n=3). The wound tissue of mice in 0 μg/mL GO composite hydrogel group and 0.1 μg/mL GO composite hydrogel group on 7 d of treatment was collected to observe the relationship between the distribution of GO and neovascularization by hematoxylin-eosin staining (n=3) and the expression of VEGF by immunohistochemical staining. Data were statistically analyzed with analysis of variance for repeated measurement, one-way analysis of variance, and Tukey's method. Results: GO had a multilayered lamellar structure with the width of about 20 μm and the length of about 50 μm. The absorbance value of HSFs in 10.0 μg/mL GO group was significantly lower than that in 0 μg/mL GO group after 48 h of culture (q=7.64, P<0.01). At 24 h after scratching, the migration rates of HSFs were similar in the four groups (P>0.05); at 36 h after scratching, the migration rate of HSFs in 0.1 μg/mL GO group was significantly higher than that in 0 μg/mL GO group, 1.0 μg/mL GO group, and 5.0 μg/mL GO group (with q values of 7.48, 10.81, and 10.20, respectively, P<0.01). At 12 h after scratching, the migration rate of HUVECs in 0.1 μg/mL GO group was significantly higher than that in 0 μg/mL GO group, 1.0 μg/mL GO group, and 5.0 μg/mL GO group (with q values of 7.11, 8.99, and 14.92, respectively, P<0.01), and the migration rate of HUVECs in 5.0 μg/mL GO group was significantly lower than that in 0 μg/mL GO group and 1.0 μg/mL GO group (with q values of 7.81 and 5.33, respectively, P<0.05 or P<0.01 ). At 4 and 6 h of culture, the VEGF expressions of HSFs in the four groups were similar (P>0.05); at 8 h of culture, the VEGF expression of HSFs in 0.1 μg/mL GO group was significantly higher than that in 0 μg/mL GO group and 5.0 μg/mL GO group (with q values of 4.75 and 4.48, respectively, P<0.05). The GO-GelMA composite hydrogels in the four groups were all red liquid before cross-linking, which turned to light yellow gel after cross-linking, with no significant difference in fluidity. The GO in the GO-GelMA composite hydrogel of 0 μg/mL GO composite hydrogel group had no release of GO at all time points; the GO in the GO-GelMA composite hydrogels of the other 3 groups was partially released on 3 d of soaking, and all the GO was released on 7 d of soaking. From 3 to 14 d of treatment, the wounds of mice in the 4 groups were covered with hydrogel dressings, kept moist, and gradually healed. On 3, 7, and 14 d of treatment, the wound healing rates of mice in the four groups were similar (P>0.05). On 3 d of treatment, the MPU ratio of wound of mice in 0.1 μg/mL GO composite hydrogel group was significantly higher than that in 0 μg/mL GO composite hydrogel group, 1.0 μg/mL GO composite hydrogel group, and 5.0 μg/mL GO composite hydrogel group (with q values of 10.70, 11.83, and 10.65, respectively, P<0.05 or P<0.01). On 7 and 14 d of treatment, the MPU ratios of wound of mice in the four groups were similar (P>0.05). The MPU ratio of wound of mice in 0.1 μg/mL GO composite hydrogel group on 7 d of treatment was significantly lower than that on 3 d of treatment (q=14.38, P<0.05), and that on 14 d of treatment was significantly lower than that on 7 d of treatment (q=27.78, P<0.01). On 7 d of treatment, the neovascular density of wound of mice on 7 d of treatment was 120.7±4.1 per 200 times of visual field, which was significantly higher than 61.7±1.3, 77.7±10.2, and 99.0±7.9 per 200 times of visual field in 0 μg/mL GO composite hydrogel group, 1.0 μg/mL GO composite hydrogel group, and 5.0 μg/mL GO composite hydrogel group (with q values of 12.88, 7.79, and 6.70, respectively, P<0.01), and the neovascular density of wound of mice in 1.0 μg/mL GO composite hydrogel group and 5.0 μg/mL GO composite hydrogel group was significantly higher than that in 0 μg/mL GO composite hydrogel group (with q values of 5.10 and 6.19, respectively, P<0.05). On 7 d of treatment, cluster of new blood vessels in wound of mice in 0.1 μg/mL GO composite hydrogel group was significantly more than that in 0 μg/mL GO composite hydrogel group, and the new blood vessels were clustered near the GO; a large amount of VEGF was expressed in wound of mice in 0.1 μg/mL GO composite hydrogel group in the distribution area of GO and new blood vessels. Conclusions: GO with mass concentration lower than 10.0 μg/mL had no adverse effect on proliferation activity of HSFs, and GO of 0.1 μg/mL can promote the migration of HSFs and HUVECs, and can promote the secretion of VEGF in HSFs. In situ photopolymerized of GO-GelMA composite hydrogel dressing can promote the wound neovascularization of full-thickness skin defect in mice and increase wound blood perfusion in the early stage, with GO showing an enrichment effect on angiogenesis, and the mechanism may be related to the role of GO in promoting the secretion of VEGF by wound cells.

Three-dimensional bioprinted microstructure promotes proliferation and viability of murine epithelial stem cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of different microstructures prepared by three-dimensional (3D) bioprinting on proliferation and viability of the murine epithelial stem cells in vitro.</p><p><b>METHODS</b>3D cell-laden microstructures were constructed using 3 different printing nozzles with diameters of 210, 340, and 420 µm. Fluorescence microscopy and the live/dead assay kit were used to observe the proliferation and viability of the murine epithelial stem cells in the microstructures.</p><p><b>RESULTS</b>All the 3D cell-laden micro-structures were capable of promoting the proliferation of murine epithelial stem cells. In the 3 groups of micro-structures, the cell viability decreased significantly with time until 7 days after printing (P<0.01), but at 14 days after the printing, the cell viability increased significantly as compared with that at 7 days (P<0.01). The viability of the cells was significantly higher in the microstructure printed using a 420 µm nozzle than in the microstructures printed with 210 µm and 340 µm nozzles (P<0.01).</p><p><b>CONCLUSION</b>The microstructure printed with a 420 µm nozzle can stably promote the proliferation of murine epithelial stem cells and maintain a high level of cell viability, suggesting the feasibility of constructing tissue-engineered epidermis and full-thickness skin graft using 3D bioprinting technique.</p>

Comparison of the histological morphology between normal skin and scar tissue / 华中科技大学学报（医学）（英德文版）

Skin wound healing is a complex event, and interrupted wound healing process could lead to scar formation. The aim of this study was to examine the morphological changes of scar tissue. Pathological staining (HE staining, Masson's trichrome staining, methenamine silver staining) was used to evaluate the morphological changes of regenerating epidermis in normal skin and scar tissue, and immunofluorescence staining to detect the expression of collagen IV, a component of basement membrane (BM), and the expression of integrinβ4, a receptor for BM laminins. Additionally, the expression of CK14, CK5, and CK10 was measured to evaluate the proliferation and differentiation of keratinocytes in normal skin and scar tissue. The results showed that the structure of the skin was histologically changed in scar tissue. Collagen IV, expressed under the epidermis of normal skin, was reduced distinctly in scar tissue. Integrinβ4, expressed in the basal layer of normal skin, was found absent in the basal layer of scar tissue. Additionally, it was found that keratinocytes in scarring epidermis were more proliferative than in normal skin. These results indicate that during the skin wound healing, altered formation of BM may affect the proliferation of keratinocytes, reepithelial and tissue remodeling, and then result in scar formation. Thus, remodeling BM structure during wound repair may be beneficial for improving healing in cutaneous wounds during clinical practice.

Comparison of the histological morphology between normal skin and scar tissue / 华中科技大学学报（医学）（英德文版）

Skin wound healing is a complex event, and interrupted wound healing process could lead to scar formation. The aim of this study was to examine the morphological changes of scar tissue. Pathological staining (HE staining, Masson's trichrome staining, methenamine silver staining) was used to evaluate the morphological changes of regenerating epidermis in normal skin and scar tissue, and immunofluorescence staining to detect the expression of collagen IV, a component of basement membrane (BM), and the expression of integrinβ4, a receptor for BM laminins. Additionally, the expression of CK14, CK5, and CK10 was measured to evaluate the proliferation and differentiation of keratinocytes in normal skin and scar tissue. The results showed that the structure of the skin was histologically changed in scar tissue. Collagen IV, expressed under the epidermis of normal skin, was reduced distinctly in scar tissue. Integrinβ4, expressed in the basal layer of normal skin, was found absent in the basal layer of scar tissue. Additionally, it was found that keratinocytes in scarring epidermis were more proliferative than in normal skin. These results indicate that during the skin wound healing, altered formation of BM may affect the proliferation of keratinocytes, reepithelial and tissue remodeling, and then result in scar formation. Thus, remodeling BM structure during wound repair may be beneficial for improving healing in cutaneous wounds during clinical practice.

Regenerative medicine and burn care in China / 中华烧伤杂志

In the recent 30 years, regenerative medicine has become a discipline with full vitality and hope owing to its tremendous demands in China. Chinese scientists in these areas have been making remarkable achievements in fields of stem cells, tissue engineering, and burns.

Future application of hair follicle stem cells: capable in differentiation into sweat gland cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Sweat glands (SGs) can not regenerate after complete destruction in the severe skin injury, so it is important to find a ideal stem cell source in order to regenerate functional SGs. Hair follicle stem cells (HFSCs) possess the obvious properties of the adult stem cells, which are multipotent and easily accessible. In this research, we attempted to direct the HFSCs suffered from the sweat gland cells (SGCs) special differentiation by a co-operative coculture system in vitro.</p><p><b>METHODS</b>The designed co-culture microenvironment in the transwell was consist of two critial factors: heat shocked SGCs and dermis-like mesenchymal tissue, which appeared independently in the two control groups; after induction, the purified induced SGC-like cells were transplanted into the full-thickness scalded wounds of the nude mice, after 4 weeks, the reconstructed SG-like structures were identified by immunohistochemical and immunofluorescence analysis.</p><p><b>RESULTS</b>A part of HFSCs in experimental group finally expressed SGCs phenotypes, by contrast, the control group 1 which just containing dermis-like mesenchymal tissue failed and the control group 2 consisted of heat shocked SGCs was in a poor efficiency; by immunofluorescence staining and flow cytometry analysis, the expression of HFSCs special biomarkers was down regulated, instead of the positive efficiency of SGCs special antigens increased; besides, the induced SGCs displayed a high expression of ectodysplasin A (EDA) and ectodysplasin A receptor (EDAR) genes and proteins; after cell transplantation, the youngest SG-like structures formed and be positive in SGCs special antigens, which never happened in untreated wounds (P < 0.05).</p><p><b>CONCLUSION</b>The HFSCs are multipotential and capable in differentiating into SGCs which promise a potential stem cells reservoir for future use; our special co-culture microenvironment is promising for HFSCs differentiating; the induced SGCs are functional and could work well in the regeneration of SGs.</p>

Study of regenerative medicine in China: Demands and clinical translation / 解放军医学杂志

The repair and regeneration of tissue is a well-discussed topic. Over the past 20 years, with the development of genetics, auxology, stem cell biology, and tissue engineering, tissue repair and regeneration have rapidly developed as emerging "Regenerative Medicine". Regenerative medicine has significant market demand in China. Based on national statistics, injury and poisoning patients rank third in afflictions in city hospitals (accounting for 9.13%) and rank second in afflictions in county hospitals (accounting for 14.07%). Totally, approximately one hundred million patients suffered from traumatic, genetic and metabolic diseases in China and demand reparative and regenerative medical treatment each year. The Chinese government and its related departments have always attached great importance and support to the development of regenerative medicine, and the Chinese academic circle is involved in a very wide range of diseases and injuries including regenerative medical theory and technology. Stem cell biology, organ engineering and duplication, tissue engineering research and production have developed rapidly, and great portion of these studies have started to appear in applications, which have aroused extensive concerns in international professional circle. In the next 10 years, the Chinese regenerative medical system will be further improved, in both statute and rules, clinical translation will be further accelerated. Breakthroughs are expected in induced differentiation of stem cells and synchronous repair and regeneration of multiple organs, construction of major organs by tissue engineering, large-scale applications of tissue engineering products, and other aspects.

The relationships of dressings and wound repair and tissue regeneration / 中华烧伤杂志

Advanced dressings play a key role in accelerating wound healing and enhancing wound healing quality. According to the development of new dressings, the following short remark represents my personal opinion and expectation regarding the dressings for promoting wound repair and tissue regeneration.

Enhance the establishment of wound healing centers and promote the specialized treatment of chronic skin wounds / 中华烧伤杂志

It is important to establish some comprehensive wound healing centers in order to treat those complicated chronic skin wounds. In this paper, I would like to summarize our practices in some hospitals dealing with the construction of wound healing centers and give my suggestions for their future development.

Transplantation of human bone marrow-derived mesenchymal stem cells transfected with ectodysplasin for regeneration of sweat glands / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Patients with severe full-thickness burn injury suffer from their inability to maintain body temperature through perspiration because the complete destructed sweat glands can not be regenerated. Bone marrow-derived mesenchymal stem cells (BM-MSCs) represent an ideal stem-cell source for cell therapy because of their easy purification and multipotency. In this study, we attempted to induce human BM-MSCs to differentiate into sweat gland cells for sweat gland regeneration through ectodysplasin (EDA) gene transfection.</p><p><b>METHODS</b>The dynamic expression of EDA and EDA receptor (EDAR) were firstly observed in the sweat gland formation during embryological development. After transfection with EDA expression vector, human BM-MSCs were transplanted into the injured areas of burn animal models. The regeneration of sweat glands was identified by perspiration test and immunohistochemical analysis.</p><p><b>RESULTS</b>Endogenous expression of EDA and EDAR correlated with sweat gland development in human fetal skin. After EDA transfection, BM-MSC acquired a sweat-gland-cell phenotype, evidenced by their expression of sweat gland markers by flow cytometry analysis. Immunohistochemical staining revealed a markedly contribution of EDA-transfected BM-MSCs to the regeneration of sweat glands in the scalded paws. Positive rate for perspiration test for the paws treated with EDA-transfected BM-MSCs was significantly higher than those treated with BM-MSCs or EDA expression vector (P < 0.05).</p><p><b>CONCLUSIONS</b>Our results confirmed the important role of EDA in the development of sweat gland. BM-MSCs transfected with EDA significantly improved the sweat-gland regeneration. This study suggests the potential application of EDA-modified MSCs for the repair and regeneration of injured skin and its appendages.</p>

Ponderance over tissue regeneration and regenerative medicine / 中华烧伤杂志

Research in the field of tissue regeneration is a new focus in life science and medicine in the 21st century, hereby I express my personal expectations of its research and translational application in the future.

The practice of wound healing center construction in China / 中华烧伤杂志

The construction of wound healing or wound care center in China is necessary for patients and about 10 wound healing or care centers have already been established during the past years. In this paper, we summarize their experience and expect their development in the future.

Effect of ecdysterone on the proliferation of human umbilical cord mesenchymal stem cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of ecdysterone on the proliferation of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro.</p><p><b>METHODS</b>hUCMSCs isolated by enzyme digestion from human umbilical cord tissues were cultured and identified for the surface antigens using fluorescence-activated cell sorting (FACS). The cells were treated with ecdysterone at the concentrations of 0, 25, 50, 100, 150, and 200 µg/ml, and the changes in the cell proliferation were detected using MTT assay.</p><p><b>RESULTS</b>The third-passage hUCMSCs were positive for CD29 and CD105 and negative for CD34 and CD45 as shown by flow cytometry. Treatment with ecdysterone resulted in significantly increased cell proliferation as compared to the control cells (P<0.05), but no significant differences were found in cells treated with 100, 150, and 200 µg/ml ecdysterone (P>0.05). The growth curves of the cells also demonstrated the definite effect of ecdysterone in promoting the proliferation of hUCMSCs.</p><p><b>CONCLUSION</b>Ecdysterone can promote the proliferation of hUCMSCs in vitro with the optimal concentration of 100 µg/ml, suggesting its potential value in the enrichment of mesenchymal stem cells.</p>

Cellular phenotype transdifferentiation of adipose-derived stem cells into endothelial cells / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the possibility of adipose derived stem cells (ADSCs) for wound healing by detecting cellular phenotype conversion of ADSCs into endothelial cells (ECs).</p><p><b>METHODS</b>ADSCs were isolated and cultured from adipose tissue derived from SD rats (n = 8), and maintained in Dulbecco's modified Eagle's medium (DMEM) containing 10% fetal bovine serum (FBS) in vitro. The marker antigen of P3 ADSCs was detected by analysis CD49d and CD106 antigens expression using flow cytometry, and the multipotential differentiation of P3 ADSCs were identified by specific medium inducing to differentiate into osteoblasts and adipocytes. And then, the ADSCs were cultured and induced for 3 days by condition culture medium (containing 30% superior of homogenating rat blood vessels in 10%FBS DMEM) as experimental group, and were cultured by 10% FBS DMEM as control group, and the expression of CD34 and von Willebrand factor (vWF) in ADSCs were analyzed by flow cytometry.</p><p><b>RESULTS</b>Flow cytometry analysis showed that the expression of CD49d and CD106 in ADSCs were positive (98.32 ± 0.37)% and negative (1.67 ± 0.61)%, respectively. The multipotential differentiation experiment demonstrated that the cultured P3 ADSCs can be induced to differentiate into osteoblasts and adipocytes in vitro. The positive rate of CD34 and vWF were (77.14 ± 0.76)% and (75.46 ± 0.37)% in condition medium group, higher than (1.38 ± 0.31)% and (1.70 ± 0.23)% in 10% FBS DMEM control group, respectively (P < 0.01).</p><p><b>CONCLUSION</b>The ADSCs can be induced to differentiated into ECs, suggesting that ADSCs have potential to take part in wound repair and angiogenesis.</p>

Effect of ecdysterone on the proliferation of human mesenchymal stem cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of ecdysterone (EDS) on the proliferation of human bone marrow mesenchymal stem cells (hMSCs) in vitro.</p><p><b>METHODS</b>hMSCs were isolated from human bone marrow cell suspension by density gradient centrifugation. The expression of integrins CD44, CD105, CD34 and CD29 were examined by immunocytochemical method. EDS at 10, 25, 50 or 100 microg/ml were added in hMSC culture system, using the routine culture medium for hMSCs as control. The cell viability were analyzed by MTT assay and the cell cycle changes were examined by flow cytometry.</p><p><b>RESULTS</b>The optical density (OD) differed significant between the EDS treatment groups and the control group (P<0.01), and 25 microg/ml EDS group showed the highest OD value (P<0.01) without significant differences among 10, 50 and 100 microg/ml EDS groups (P>0.05). Flow cytometry showed that treatment of the cells with 25 microg/ml EDS significantly increased the cell percentages in S and G(2)M phases and the proliferation index (PI) of the cells as compared with the control group.</p><p><b>CONCLUSION</b>Within a given concentration range, EDS can promote the proliferation of hMSCs in vitro, and this effect can be the most obvious at the concentration of 25 microg/ml. The effect of EDS in promoting the proliferation of hMSCs does not positively correlate to EDS concentration administered.</p>

Dedifferentiation of epidermal cells into transit amplifying cells induced by bFGF / 南方医科大学学报

<p><b>OBJECTIVE</b>TTo explore the method for inducing the dedifferentiation of epidermal cells into their progenitor stem cells in vitro without external gene intervention.</p><p><b>METHODS</b>HEK cells obtained from Casacade were induced to reverse their differentiated process and produce immature stem-like cells, namely the dedifferentiation derived epidermal stem cells (dESCs), by induction with basic fibroblasts growth factors (bFGF) in vitro. Immunochemical staining, flow FACS analysis, RT-PCR and immunofluorescent staining were used to detect the phenotypic and functional changes of the differentiated epidermal cells, using human epidermal stem cells (ESCs) as the positive control.</p><p><b>RESULTS</b>Immunohistochemical staining revealed that the expressions of β₁-integrin, CK19 and CK14 were up-regulated, while CK10 expression was down-regulated significantly after bFGF treatment. Two-color flow cytometric analysis of α₆-integrin and CD71 showed that the percentages of α₆(+)CD71(-), α₆(+)CD71(+) and CD71(+) expressing populations reached 13.24%, 58.26% and 23.12% of the total isolated cells, as compared with those of the control (0.12%, 3.06%, 51.50%) and positive control cells (37.49%, 45.13%, 5.86%). RT-PCR analysis indicated that the relative gene expressions of β₁-integrin, CK19 and CK14 increased in bFGF treatment group, whereas the expression of CK10 was significantly suppressed. Although there was no significant difference in the expression levels of β₁ integrin, CK19 and CK10 between the bFGF-treated and the positive controls, the expression of CK14 in bFGF-treated cells showed a 1.4-fold increase as compared with that in ESCs (P < 0.05). Immunofluorescent staining showed that a regional difference in the subcellular localization of telomerase between dESCs and ESCs.</p><p><b>CONCLUSION</b>bFGF can induce the epidermal cells to convert into epidermal precursor cells. Although they are more likely to be transient amplifying cells, the method for reprogramming somatic epidermal cells into their progenitors by bFGF induction other than genetic manipulation offers a new approach to generate residual healthy stem cells for wound repair and regeneration.</p>