Biomaterial-based mechanical regulation facilitates scarless wound healing with functional skin appendage regeneration.

Scar formation resulting from burns or severe trauma can significantly compromise the structural integrity of skin and lead to permanent loss of skin appendages, ultimately impairing its normal physiological function. Accumulating evidence underscores the potential of targeted modulation of mechanical cues to enhance skin regeneration, promoting scarless repair by influencing the extracellular microenvironment and driving the phenotypic transitions. The field of skin repair and skin appendage regeneration has witnessed remarkable advancements in the utilization of biomaterials with distinct physical properties. However, a comprehensive understanding of the underlying mechanisms remains somewhat elusive, limiting the broader application of these innovations. In this review, we present two promising biomaterial-based mechanical approaches aimed at bolstering the regenerative capacity of compromised skin. The first approach involves leveraging biomaterials with specific biophysical properties to create an optimal scarless environment that supports cellular activities essential for regeneration. The second approach centers on harnessing mechanical forces exerted by biomaterials to enhance cellular plasticity, facilitating efficient cellular reprogramming and, consequently, promoting the regeneration of skin appendages. In summary, the manipulation of mechanical cues using biomaterial-based strategies holds significant promise as a supplementary approach for achieving scarless wound healing, coupled with the restoration of multiple skin appendage functions.

Surgical amputation for patients with diabetic foot ulcers: A Chinese expert panel consensus treatment guide.

Background: Diabetic foot disease is a serious complication of diabetes mellitus. Patients with diabetes mellitus have a 25% lifetime risk for developing a foot ulcer, and between 14% and 24% of patients require a major or minor lower limb amputation due to severe gangrene. However, decisions concerning whether to amputate or whether to perform a major or minor lower limb amputation, and how best to determine the amputation plane remain unclear. Methods: To consolidate the current literature with expert opinion to make recommendations that will guide surgical amputation for patients with diabetic foot ulcers. A total of 23 experts experienced in surgical treatment of patients with diabetic foot ulcers formed an expert consensus panel, and presented the relevant evidence, discussed clinical experiences, and derived consensus statements on surgical amputation for patients with diabetic foot ulcers. Each statement was discussed and revised until a unanimous consensus was achieved. Results: A total of 16 recommendations for surgical amputation for patients with diabetic foot ulcers were formulated. The experts believe that determination of the amputation plane should be comprehensively evaluated according to a patient's general health status, the degree of injury, and the severity of lower limb vasculopathy. The Wagner grading system and the severity of diabetic lower extremity artery disease are important criteria when determining the degree of amputation. The severity of both diabetic foot infection and systemic underlying diseases are important factors when considering appropriate treatment. Moreover, consideration should also be given to a patient's socioeconomic status. Given the complexities of treating the diabetic foot, relevant issues in which consensus could not be reached will be discussed and revised in future. Conclusion: This expert consensus could be used to guide doctors in clinical practice, and help patients with diabetic foot ulcers gain access to appropriate amputation treatment.

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 (SG), 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), carcino-embryonic 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 a 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: EDA overexpression drove HDF conversion into iSGCs in SG culture medium (SGM). qPCR indicated significantly increased mRNA levels of the SG markers CK5, CK18 and 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. CONCLUSION: 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.

Small extracellular vesicles from mesenchymal stem cells: A potential Weapon for chronic non-healing wound treatment.

Chronic non-healing wounds have posed a severe threat to patients mentally and physically. Behavior dysregulation of remaining cells at wound sites is recognized as the chief culprit to destroy healing process and hinders wound healing. Therefore, regulating and restoring normal cellular behavior is the core of chronic non-healing wound treatment. In recent years, the therapy with mesenchymal stem cells (MSCs) has become a promising option for chronic wound healing and the efficacy has increasingly been attributed to their exocrine functions. Small extracellular vesicles derived from MSCs (MSC-sEVs) are reported to benefit almost all stages of wound healing by regulating the cellular behavior to participate in the process of inflammatory response, angiogenesis, re-epithelization, and scarless healing. Here, we describe the characteristics of MSC-sEVs and discuss their therapeutic potential in chronic wound treatment. Additionally, we also provide an overview of the application avenues of MSC-sEVs in wound treatment. Finally, we summarize strategies for large-scale production and engineering of MSC-sEVs. This review may possibly provide meaningful guidance for chronic wound treatment with MSC-sEVs.

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.

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.

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 whole-cell 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. CONCLUSION: 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.

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-qPCR 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 neuron-like 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, NeuN, and Synapsin 1 and motor neuron markers HB9, ISL1, CHAT, and VAChT. 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. CONCLUSION: 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.

Berberine: A Traditional Natural Product With Novel Biological Activities.

CONTEXT: Having been used for thousands of years to treat gastrointestinal diseases, the natural isoquinoline alkaloid, berberine, has exhibited a wide spectrum of biochemical and pharmacological effects in studies of recent years. OBJECTIVE: The review intended to examine the many novel bioactivities of berberine, including antidiabetic, anticancer, neuroprotective, anti-inflammatory, and anti-atherosclerotic actions. DESIGN: The research team searched the MEDLINE database using PubMed, using different keyword combinations, including berberine AND diabetes, berberine AND cancer, berberine AND (neuron OR brain), berberine AND inflammation, and "berberine AND atherosclerosis to find studies evaluating the various effects exerted berberine. CONCLUSION: Berberine is a promising multipotent agent to combat diabetes, cancer, Alzheimer's disease, and other diseases.

Critical role of the endogenous renin-angiotensin system in maintaining self-renewal and regeneration potential of epidermal stem cells.

A tightly controlled activity of renin-angiotensin system (RAS) including renin, angiotensin-converting enzymes (ACEs), and angiotensin II (Ang II) receptors is critical not only for maintaining systemic hemodynamics and blood volume but also for controlling cell proliferation, differentiation, and tissue remodeling in target organs. ACE inhibitors or Ang II receptor type 1 (AT1R) blockers are widely used as first line drugs for the treatment of cardiovascular diseases that are caused by chronical activation of RAS. However, about 15% of patients using ACE inhibitors develop side effects in the skin and the underlying mechanisms have been poorly understood or even neglected. Herein we show an endogenous RAS in maintaining self-renewal and regeneration potential of epidermal stem cells (ESCs) thereby contributing to wound healing. Firstly, we found that ESCs may express ACE, and its members in wound edges were positively associated with wound healing in Captopril-treated rats. Secondly, we demonstrated that human ESCs had a functional RAS including ACE1, ACE2, Ang II, AT1R, and AT2R. ACE-Ang II axis maintains human ESC function via activation of both AT1R and AT2R, which are negatively regulated by each other. Ang II-induced activation of extracellular signal-regulated kinase (ERK) and signal transducers and activators of transcription (STAT)1 and STAT3 was mediated by the negative cross-talk between AT1R and AT2R in human ESCs. These results suggest that Ang II is a critical regulator of ESC function and ESC-mediated epidermal regeneration. Inappropriate interruption of Ang II-operated signaling may prejudice ESC function leading to impaired skin wound healing or even disease.

Complicated HCV subtype expansion among drug users in Guangdong province, China.

Guangdong Province is one of the most developed and populous provinces in southern China. The subtype situation of hepatitis C virus (HCV) in Guangdong remains unknown. The aim of this study was to investigate and estimate the HCV subtypes in drug users (DU) using a city-based sampling strategy to better understand the characteristics of HCV transmission in Guangdong. Archived plasma samples (n = 1074) from DU who were anti-HCV positive in 2014 were selected randomly from 20 cities in Guangdong Province. Subtypes were determined based on core and/or E1 sequences using phylogenetic analysis. The distributions of HCV subtypes in DU and different regions were analyzed. A total of 8 genotypes were identified. The three main HCV subtypes in DU in Guangdong were 6a (63.0%), 3a (15.2%), and 3b (11.8%). Significant differences were discovered among different registered residency and regions but not among genders, marital status, education level, or drug use patterns. HCV subtype 3b was significantly higher in Guangdong residents than in non-Guangdong residents. In contrast, HCV subtype 6a was significantly lower in Guangdong residents than in non-Guangdong residents. Subtype 1b in eastern Guangdong (eastern) was significantly lower, while 6a was significantly higher when compared with other regions. Subtype 3a in the Pearl River Delta (PRD) region was significantly higher, while 3b was significantly lower when compared with other regions. In western Guangdong, HCV subtype 3a was significantly lower when compared with other regions. Additionally, in northern Guangdong subtypes 1b and 3b were significantly higher, while 6a was significantly lower when compared with other regions. Our study revealed the diversity and distribution of HCV subtypes in DU in nearly all the cities in Guangdong. The results provide essential information that will allow the establishment of specific intervention strategies that may help prevent HCV transmission.

Synthetic poly(vinyl alcohol)-chitosan as a new type of highly efficient hemostatic sponge with blood-triggered swelling and high biocompatibility.

Rapid and effective hemostasis for a noncompressible hemorrhage is the key to control bleeding and reduce mortality. Chitosan (CS) has been widely used as a popular hemostatic dressing; however, irregularly shaped wounds present in emergencies limit the performance of CS powder. To improve the hemostatic effect of CS, we modified it with poly(vinyl alcohol) (PVA), a fast-swelling sponge triggered by water. The novel synthetic PVA-CS was prepared by cross-linking PVA and CS during foaming and crosslinking reactions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction were utilized to analyze the characteristics of PVA-CS. In vitro, the swelling ratio and blood clotting ability were evaluated in different groups with various weight ratios or degrees of deacetylation of the CS, and the cytocompatibility and cell attachment on the material were analyzed by human dermal fibroblast (HDF) cell testing. In vivo, the hemostatic effects were evaluated in Sprague-Dawley rats and Bama miniature pigs in a femoral artery hemorrhage model or gunshot wound experiment. PVA-CS presents robust mechanical strength, rapid water-triggered swelling and a fast absorption speed. As compared with gauze and PVA, which are widely used in first aid, PVA-CS sponges showed an improved blood clotting ability and increased blood cell and platelet adhesion and activation. The PVA-CS sponges also showed high biocompatibility in cell viability, cell proliferation and cell attachment bioassays. Furthermore, in vivo evaluation of the PVA-CS sponges revealed excellent hemostatic performance and enhanced wound healing with increased re-epithelialization and decreased granulation tissues. The results of this study strongly support the use of these composite sponges for noncompressible hemorrhage in acute trauma and ballistic injuries.

Efficacy and safety of extracorporeal shock wave therapy for acute and chronic soft tissue wounds: A systematic review and meta-analysis.

This study aimed to evaluate and compare the effects of extracorporeal shock wave therapy (ESWT) and conventional wound therapy (CWT) for acute and chronic soft tissue wounds. All English-language articles on ESWT for acute and chronic soft tissue wounds indexed in PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, Cochrane Library, Physiotherapy Evidence Database, and HealthSTAR published prior to June 2017 were included, as well as corresponding articles cited in reference lists of related review articles. The methodological quality of the selected studies was assessed with the Cochrane Collaboration's "risk of bias" tool. Study design, subject demographics, wound aetiology, treatment protocols, assessment indexes, and follow-up duration were extracted. The fixed or random-effects model was used to calculate the pooled effect sizes according to studies' heterogeneity. Ten randomised controlled trials (RCTs) involving 473 patients were included in this systematic review and meta-analysis. The meta-analysis showed that ESWT statistically significantly increased the healing rate of acute and chronic soft tissue wounds 2.73-fold (odds ratio, OR = 3.73, 95% confidence interval, CI: 2.30-6.04, P < .001) and improved wound-healing area percentage by 30.45% (Standardized Mean Difference (SMD) = 30.45; 95% CI: 23.79-37.12; P < .001). ESWT reduced wound-healing time by 3 days (SMD = -2.86, 95% CI:-3.78 to -1.95, P < .001) for acute soft tissue wounds and 19 days (SMD = -19.11, 95% CI: -23.74 to -14.47, P < .001) for chronic soft tissue wounds and the risk of wound infection by 53% (OR = 0.47, 95% CI: 0.24-0.92, P = .03) when compared with CWT alone. Serious adverse effects were not reported. ESWT showed better therapeutic effects on acute and chronic soft tissue wounds compared with CWT alone. However, higher-quality and well-controlled RCTs are needed to further assess the role of ESWT for acute and chronic soft tissue wounds.

[Three-dimensional bioprinted microstructure promotes proliferation and viability of murine epithelial stem cells in vitro].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Comparative Proteomic Analysis of the Effect of the Four-Herb Chinese Medicine ANBP on Promoting Mouse Skin Wound Healing.

Traditional Chinese medicine has great potential to improve wound healing. ANBP, the mixture of 4 Chinese herbs- Agrimoniapilosa, Nelumbonucifera, Boswelliacarteri, and Pollen typhae-is effective in trauma treatment while its mechanism is still elusive. In this study, quantitative proteomics and bioinformatics analyses were performed to decipher the possible roles of ANBP in accelerated wound healing of mouse skin. Among all 3171 identified proteins, 90, 71, 80, and 140 proteins were found to be differently expressed in 6 hours, 3 days, 7 days, and 14 days ANBP-treated tissues compared with corresponding control tissues, respectively. The result showed that different biological processes and pathways were activated at different healing stages. At the early healing stage, ANBP treatment mainly affected several biological processes, including immune and defense response, vascular system restoration, hemostasis and coagulation regulation, lipid metabolism and signal transduction, while muscle tissue, hair, epidermis, extracellular matrix and tissue remodeling related activities were the major events in ANBP promoted later wound healing. This is the first quantitative proteome study of ANBP-treated wound tissues, which provide a new perspective for the mechanism of ANBP accelerated wound healing and is of guiding significance for clinical application of ANBP in trauma disorders cure.