In situ forming injectable MSC-loaded GelMA hydrogels combined with PD for vascularized sweat gland regeneration

Dear Editor,Three dimensional(3D)bioprinted extracellular matrix(ECM)can be used to provide both biochemical and biophysical cues to direct mesenchymal stem cells(MSCs)differentiation,and then differentiated cells were isolated for implantation in vivo using surgical procedures.However,the reduced cell activity after cell isolation from 3D constructs and low cell retention in injured sites limit its application[1].Methacrylated gelatin(GelMA)hydrogel has the advantage of fast crosslinking,which could resemble complex architectures of tissue construct in vivo[2].Here,we adopted a noninvasive bioprinting procedure to imitate the regenerative microenvironment that could simultaneously direct the sweat gland(SG)and vascular differentiation from MSCs and ultimately promote the replacement of glandular tissue in situ(Fig.1a).

Medical rescue of naval combat: challenge and future

There has been no large-scale naval combat in the last 30 years. With the rapid development of battleships, weapons manufacturing and electronic technology, naval combat will present some new characteristics. Additionally, naval combat is facing unprecedented challenges. In this paper, we discuss the topic of medical rescue at sea: what challenges we face and what we could do. The contents discussed in this paper contain battlefield self-aid buddy care, clinical skills, organized health services, medical training and future medical research programs. We also discuss the characteristics of modern naval combat, medical rescue challenges, medical treatment highlights and future developments of medical rescue at sea.

Acid fibroblast growth factor reduces rat intestinal mucosal damage caused by ischemia-reperfusion insult

AIM: To detect the effects of acid fibroblast growth factor (aFGF) on apoptosis and proliferation of intestinal epithelial cells in differentiation or proliferation status to explore the protective mechanisms of aFGF.METHODS: Wistar rats were randomly divided into sham-operated control group (C, n = 6), intestinal ischemia group (I,n = 6), aFGF treatment group (A,n =48) and intestinal ischemia-reperfusion group (R, n = 48). Apoptosis of intestinal mucosal cells was determined with terminal deoxynucleotidyl transferasemediated dUTP-biotin nick-end labeling (TUNEL)technique. Proliferating cell nuclear. antigen (PCNA)protein expression and distribution were detected with immunohistochemical method. Plasma levels of D-lactate were determined with modified Brandts method.RESULTS: In A group, administration of exogenous aFGF could improve intestinal histological structure and decrease plasma D-lactate levels at 2-12 h after the reperfusion compared with R group. The apoptotic rates and PCNA protein expressions were not increased until 2 h after reperfusion and were maximal at 12 h. After reperfusion for 2-12 h, the apoptotic rates were gradually augmented along the length of jejunal crypt-villus units.Administration of aFGF could significantly reduce the apoptotic response at 2-12 h after reperfusion (P＜0.05).Apoptosis rates in villus and crypt epithelial cells in A group at 12 h after reperfusion were (62.5±5.5)% and (73.2±18.6)% of those in R group, respectively.Treatment of aFGF could apparently induce protein expression of PCNA in intestinal mucosal cells of A group compared with R group during 2-12 h after reperfusion (P＜0.05). There were approximately 1.3- and 1.5-times increments of PCNA expression levels in villus and crypt cells in A group at 12 h after reperfusion compared with R group, respectively.CONCLUSION: Intestinal I/R insult could lead to histological structure change and apoptotic rate increment. The protective effects of aFGF against ischemia/reperfusion in rat intestinal mucosa might be partially due to its ability to inhibit ischemia/reperfusioninduced apoptosis and to promote cell proliferation of crypt cells and villus epithelial cells.

Exogenous acid fibroblast growth factor inhibits ischemia-reperfusion-induced damage in intestinal epithelium via regulating P53 and P21WAF-1 expression

AIM: To detect the effect of acid fibroblast growth factor (aFGF) on P53 and P21WAF-1 expression in rat intestine after ischemia-reperfusion (I-R) injury in order to explore the protective mechanisms of aFGF.METHODS: Male rats were randomly divided into four groups, namely intestinal ischemia-reperfusion group (R),aFGF treatment group (A), intestinal ischemia group (I),and sham-operated control group (C). In group I, the animals were killed after 45 min of superior mesenteric artery (SMA) occlusion. In groups R and A, the rats sustained for 45 min of SMA occlusion and were treated with normal saline (0.15 mL) and aFGF (20 μg/kg, 0.15 mL),then sustained at various times for up to 48 h after reperfusion. In group C, SMA was separated, but without occlusion. Apoptosis in intestinal villi was determined with terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling technique (TUNEL).Intestinal tissue samples were taken not only for RTPCR to detect P53 and P21WAF-1 gene expression, but also for immunohistochemical analysis to detect P53 and P21WAF-1 protein expression and distribution.RESULTS: In histopathological study, ameliorated intestinal structures were observed at 2, 6, and 12 h after reperfusion in A group compared to R group. The apoptotic rates were (41.17±3.49)%, (42.83±5.23)%,and (53.33±6.92)% at 2, 6, and 12 h after reperfusion,respectively in A group, which were apparently lower than those in R group at their matched time points(50.67±6.95)%, (54.17±7.86)%, and (64.33±6.47)%,respectively, (P＜0.05)). The protein contents of P53and P21WAF-1 were both significantly decreased in A group compared to R group (P＜0.05) at 2-12 h after reperfusion, while the mRNA levels of P53 and P21WAF-1in A group were obviously lower than those in R group at6-12 h after reperfusion (P＜0.05).CONCLUSION: P53 and P21WAF-1 protein accumulations are associated with intestinal barrier injury induced by I-R insult, while intravenous aFGF can alleviate apoptosis of rat intestinal cells by inhibiting P53 and P21WAF-1protein expression.

Protective effects of non-mitogenic human acidic fibroblast growth factor on hydrogen peroxide-induced damage to cardiomyocytes in vitro

AIM: To study the protective effect of non-mitogenic human acidic fibroblast growth factor (FGF) on cardiac oxidative injury in vivo.METHODS: Ventricular cardiomyocytes were isolated from 1- to 3-d-old neonatal SD mice and cultured in Dulbecco's minimum essential medium supplemented with 15% fetal bovine serum under an atmosphere of 50 mL/L CO2-95% air at 37 ℃, as well as assessed by immunocytochemical assay. We constructed the cardiomyocyte injury model by exposure to a certain concentration of H2O2.Cellular viability, superoxide dismutase (SOD) activity,leakage of maleic dialdehyde and anti-apoptosis effect were included to evaluate the cardiac protective effect of non-mitogenic human acidic FGF.RESULTS: Over 50% of the cardiomyocytes beat spontaneously on the 2nd d of culture and synchronously beat after being cultured for 3 d. Forty-eight hours after plating was completed, the purity of such cultures was 95% myocytes, assessed b,y an immunocytochemical assay. Cellular viability dramatically decreased with the increasing of the concentration of H2O2. Non-mitogenic human acidic FGF showed significant resistance to the toxic effect of H2O2, significantly increased the cellular viability as well as the activity of SOD, and dramatically decreased the leakage of maleic dialdehyde as well as the cellular apoptosis rate.CONCLUSION: Hydrogen peroxide shows strong cytotoxicity to the cultured cardiac myocytes, and non-mitogenic human acidic FGF shows strong cardio-protective effect when exposed to a certain concentration of H2O2.

Small molecules facilitate single factor-mediated sweat gland cell reprogramming

Background: Large skin defects severely disrupt the overall skin structure and can irreversibly damage sweat glands(SGs), thus impairing the skin’s physiological function. This study aims to develop a stepwise reprogramming strategy to convert fibroblasts into SG lineages, which may provide a promising method to obtain desirable cell types for the functional repair and regeneration of damaged skin.Methods: The expression of the SG markers cytokeratin 5(CK5), cytokeratin 10(CK10), cytokeratin 18(CK18), carcinoembryonic antigen(CEA), aquaporin 5(AQP5) and α-smooth muscle actin(α-SMA) was assessed with quantitative PCR(qPCR), immunofluorescence and flow cytometry. Calcium activity analysis was conducted to test the function of induced SG-like cells(iSGCs). Mouse xenograft models were also used to evaluate the in vivo regeneration of iSGCs.BALB/c nude mice were randomly divided into normal group, SGM treatment group and iSGC transplantation group.Immunocytochemical analyses and starch-iodine sweat tests were used to confirm the in vivo regeneration of iSGCs.Results: Ectodermal dysplasia antigen(EDA) overexpression drove human dermal fibroblast(HDF) conversion into i SGCs in SG culture medium(SGM). qPCR indicated significantly increased mRNA levels of the SG markers CK5, CK18and CEA in iSGCs, and flow cytometry data demonstrated(4.18±0.04)% of iSGCs were CK5 positive and(4.36±0.25)%of iSGCs were CK18 positive. The addition of chemical cocktails greatly accelerated the SG fate program. qPCR results revealed significantly increased mRNA expression of CK5, CK18 and CEA in iSGCs, as well as activation of the duct marker CK10 and luminal functional marker AQP5. Flow cytometry indicated, after the treatment of chemical cocktails,(23.05±2.49)% of iSGCs expressed CK5^(+) and(55.79±3.18)% of iSGCs expressed CK18^(+), respectively. Calcium activity analysis indicated that the reactivity of iSGCs to acetylcholine was close to that of primary SG cells [(60.79±7.71)% vs.(70.59±0.34)%, ns]. In vivo transplantation experiments showed approximately(5.2±1.1)% of the mice were sweat test positive, and the histological analysis results indicated that regenerated SG structures were present in iSGCs-treated mice.Conclusions: We developed a SG reprogramming strategy to generate functional iSGCs from HDFs by using the single factor EDA in combination with SGM and small molecules. The generation of iSGCs has important implications for future in situ skin regeneration with SG restoration.

Regenerative medicine in China:main progress in different fields

Regenerative medicine(RM) is an emerging interdisciplinary field of research and China has developed the research quickly and impressed the world with numerous research findings in stem cells,tissue engineering,active molecules and gene therapy.Important directions are induced differentiation of induced pluripotent stem and embryo stem cells as well as somatic stem cell differentiation potential and their application in trauma,burns,diseases of aging and nerve regeneration.The products Activ Skin and bone repair scaffolds have been approved and are applied in the clinic,and similar products are being studied.About 10 engineered growth-factor drugs for repair and regeneration have been approved and are used in the clinic.Gene therapy,therapeutic cloning and xenotransplantation are some of the strategies being studied.However,China needs to develop standards,regulations and management practices suitable for the healthy development of RM.Aspects that should be strengthened include sound administrative systems,laws,and technical specifications and guidelines;conservation of stem cell resources;emphasis on training and retention of talented stem cell researchers;and reasonable allocation of resources,diversification of investment and breakthroughs in key areas.Finally,broad and deep international cooperation is necessary.

Repair cell first,then regenerate the tissues and organs

Wound healing,tissue repair and regenerative medicine are in great demand,and great achievements in these fields have been made.The traditional strategy of tissue repair and regeneration has focused on the level of tissues and organs directly;however,the basic process of repair at the cell level is often neglected.Because the cell is the basic unit of organism structure and function;cell damage is caused first by ischemia or ischemia-reperfusion after severe trauma and injury.Then,damage to tissues and organs occurs with massive cell damage,apoptosis and even cell death.Thus,how to achieve the aim of perfect repair and regeneration?The basic process of tissue or organ repair and regeneration should involve repair of cells first,then tissues and organs.In this manuscript,it is my consideration about how to repair the cell first,then regenerate the tissues and organs.

Military medicine in China: Old topic, new concept

Military medicine is important in both war and peace. In China, military medicine plays a key role in supporting and maintaining health, in preventing injuries and diseases in military staff and in enhancing the military armed forces during war. Additionally, military medicine participates in actions such as emergency public health crises, natural disasters, emerging conflicts and anti-terrorist campaigns during peacetime. In this paper, we summary the current condition and achievements in military medicine in China and provide our perspective for its future.

Efficient and rapid conversion of human astrocytes and ALS mouse model spinal cord astrocytes into motor neuron-like cells by defined small molecules

Background: Motor neuron degeneration or loss in the spinal cord is the characteristic phenotype of motor neuron diseases or spinal cord injuries. Being proliferative and located near neurons, astrocytes are considered ideal cell sources for regenerating neurons.Methods: We selected and tested different combinations of the small molecules for inducing the conversion of human and mouse astrocytes into neurons. Microscopic imaging and immunocytochemistry analyses were used to characterize the morphology and phenotype of the induced neurons while RT-q PCR was utilized to analyze changes in gene expression. In addition, whole-cell patch-clamp recordings were measured to examine the electrophysiological properties of induced neurons.Results: The results showed that human astrocytes could be rapidly and efficiently converted into motor neuronlike cells by treatment with defined small molecules, with a yield of over 85% motor neuron-like cells attained. The induced motor neuron-like cells expressed the pan-neuronal markers TUJ1, MAP2, Neu N, and Synapsin 1 and motor neuron markers HB9, ISL1, CHAT, and VACh T. During the conversion process, the cells did not pass through a proliferative neural progenitor cell intermediate. The induced motor neurons were functional, showing the electrophysiological properties of neurons. The same chemical cocktail could induce spinal cord astrocytes from an amyotrophic lateral sclerosis mouse model carrying a SOD1 mutation to become motor neuron-like cells that exhibited a decrease in cell survival and an increase in oxidative stress compared to that observed in wild-type MNs derived from healthy mice. Moreover, the chemical induction reduced oxidative stress in the mutant astrocytes.Conclusions: The results of the present study demonstrated the feasibility of chemically converting human and mouse astrocytes into motor neuron-like cells that are useful for neurodegenerative disease modeling and regenerative medicine.

FHL2 Antagonizes Id1-Promoted Proliferation and Invasive Capacity of Human MCF-7 Breast Cancer Cells

Objective：FHL2 was previously identified to be a novel interacting factor of Id family proteins.The aim of this study was to investigate,the effects of FHL2 on Id1-mediated transcriptional regulation activity and its oncogenic activity in human breast cancer cells.Methods：Cell transfection was performed by Superfect reagent.Id1 stably overexpressed MCF-7 cells was cloned by G418 screening.The protein level of Id1 was detected by western blot analysis.Dual relative luciferase assays were used to measure the effect of E47-mediated transcriptional activity in MCF-7 human breast cancer cells.MTT assay was used to measure cell proliferation.Transwell assay was used to measure the invasive capacity of MCF-7 cancer cells.Results：The basic helix-loop-helix（bHLH） factor E47-mediated transcription activity was markedly repressed by Id1 in MCF-7 cells.This Id1-mediated repression was effectively antagonized by FHL2 transduction.Overexpression of Id1 markedly promoted the proliferation rate and invasive capacity of MCF-7 cells;however,these effects induced by Id1 were significantly suppressed by overexpression of FHL2 in cells.Conclusion：FHL2 can inhibit the proliferation and invasiveness of human breast cancer cells by repressing the functional activity of Id1.These findings provide the basis for further investigating the functional roles of FHL2-Id1 signaling in the carcinogenesis and development of human breast cancer.

Direct conversion of human fibroblasts into dopaminergic neuron-like cells using small molecules and protein factors

Background:Generation of neurons is essential in cell replacement therapy for neurodegenerative disorders like Parkinson’s disease.Several studies have reported the generation of dopaminergic(DA)neurons from mouse and human fibroblasts by ectopic expression of transcription factors,in which genetic manipulation is associated with potential risks.Methods:The small molecules and protein factors were selected based on their function to directly induce human fetal lung IMR-90 fibroblasts into DA neuron-like cells.Microscopical,immunocytochemical,and RT-qPCR analyses were used to characterize the morphology,phenotype,and gene expression features of the induced cells.The wholecell patch-clamp recordings were exploited to measure the electrophysiological properties.Results:Human IMR-90 fibroblasts were rapidly converted into DA neuron-like cells after the chemical induction using small molecules and protein factors,with a yield of approximately 95%positive TUJ1-positive cells.The induced DA neuron-like cells were immunopositive for pan-neuronal markers MAP2,NEUN,and Synapsin 1 and DA markers TH,DDC,DAT,and NURR1.The chemical induction process did not involve a neural progenitor/stem cell intermediate stage.The induced neurons could fire single action potentials,which reflected partially the electrophysiological properties of neurons.Conclusions:We developed a chemical cocktail of small molecules and protein factors to convert human fibroblasts into DA neuron-like cells without passing through a neural progenitor/stem cell intermediate stage.The induced DA neuron-like cells from human fibroblasts might provide a cellular source for cell-based therapy of Parkinson’s disease in the future.

A cross-sectional study of olfactory and taste disorders among COVID-19 patients in China

To determine the prevalence and clinical features of olfactory and taste disorders among coronavirus disease 2019(COVID-19)patients in China.A cross-sectional study was performed in Wuhan from April 3,2020 to April 15,2020.A total of 187 patients with confirmed severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)completed face-to-face interviews or telephone follow-ups.We found that the prevalence of olfactory and taste disorders was significantly lower in the Chinese cohort than in foreign COVID-19 cohorts.Females were more prone to olfactory and taste disorders.In some patients,olfactory and taste disorders precede other symptoms and can be used as early screening and warning signs.

Regional trauma system development in Shenzhen,China:an 8-year journey

Dear Editor,Since the late 1980s, trauma in China has been identified as a major public health challenge, with trafic-related fatalities accounting for 80% of accidental deaths[1]. In 2019, Shenzhen had a total population of approximately 20 million, and from 2010 to 2017, both emergency medical services and the total number of trauma patients increased, with trauma accounting for 47.0% and 38.4% of all patients in 2010 and 2017, respectively[2,3]. This report describes the efforts to implement programs and establish a trauma system in Shenzhen, China.