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Wound healing is a multi-step process that includes multiple cellular events such as cell proliferation, cell adhesion, and chemotactic response as well as cell apoptosis. Accumulating studies have documented the significance of stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor 4 (CXCR4) signaling in wound repair and regeneration. However, the molecular mechanism of regeneration is not clear. This review describes various types of tissue regeneration that CXCR4 participates in and how the efficiency of regeneration is increased by CXCR4 overexpression. It emphasizes the pleiotropic effects of CXCR4 in regeneration. By delving into the specific molecular mechanisms of CXCR4, we hope to provide a theoretical basis for tissue engineering and future regenerative medicine., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Li, Liu, Ji, Li, Xiang, Zhou, Gao, Zhang, Sun, Fu and Li.)

Full-thickness skin wounds are common accidents. Although healing can be achieved by treatments like autologous skin grafts, donor site morbidity is hardly evitable. In this article, we provide compelling evidence demonstrating that artificial dermal template (ADT)-treated wound healing is achieved by regrowth of skin epidermis as well as adnexa without skin grafts by use of rodent models. First, by fixating a chamber to the wound edge, we confirmed that wound healing was achieved by regeneration instead of contracture. We found highly proliferative cells in adnexa in the newly formed skin. In the distal edge of newly formed skin, we identified immature hair follicles at early developing stages, suggesting they were newly regenerated. Second, we observed that the Lgr5-positive hair follicle stem cells contributed to formation of new hair follicles through a lineage tracing model. Also, Lgr6-positive cells were enriched in distal edge of newly developed skin. Finally, WNT signaling pathway mediators were highly expressed in the new skin epidermis and adnexa, implying a potential role of WNT signaling during ADT treatment-stimulated skin regrowth. Taken together, our findings demonstrated that full skin regrowth can be induced by ADT treatment alone, thus arguing for its wide clinical application in skin wound treatment.

A high matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 (MMP9/TIMP1) ratio is associated with poor ulcer healing, yet how the ratio of MMP9/TIMP1 changes in diabetic foot ulcers (DFUs) with infection and how these changes may affect wound healing remain unclear. Therefore, the objective of this investigation was to explore relationships among the MMP9/TIMP1 ratio, infection, and DFUs. After being informed of the details of this study, 32 patients signed consent forms. Skin biopsies were performed for all patients. Wound tissues were obtained from all patients with wounds, and healthy skin samples were collected from patients without wounds during orthopedic surgery. Microbial cultures were obtained using the samples from diabetic patients with wounds. All patients were divided into 4 groups according to colony-forming units (CFUs) per gram of tissue (>1 × 10 6 or <1 × 10 6 ): group A (diabetic wounds with high quantities of bacteria), group B (diabetic wounds with low quantities of bacteria), group C (diabetic patients without wounds), and group D (nondiabetic patients with wounds). In addition, the biopsies were evaluated by both reverse transcription-quantitative polymerase chain reaction and Western blotting to assess the levels of MMP9, TIMP1, and vascular endothelial growth factor (VEGF). The results show that for both mRNA and protein, expression of MMP9 (fold change 1.14 ± 0.12 vs 0.60 ± 0.08 vs 0.39±0.09 vs 0.13 ± 0.06, P < .01) decreased, whereas that of TIMP1 (1.01 ± 0.09 vs 2.86 ± 0.85 vs 4.88 ± 0.83 vs 7.29 ± 1.55, P < .01) and VEGF (1.01 ± 0.22 vs 3.55 ± 0.97 vs 5.72 ± 0.55 vs 6.92 ± 1.55, P < .01) increased from group A to group D. These results suggest that an increase in the MMP9/TIMP1 ratio in infected DFUs may induce a decrease in VEGF expression.

Objective: This study aimed to evaluate the effectiveness of podiatrists in preventing diabetic foot ulcers (DFUs) in China. Method: The study was a prospective investigation. A total of 300 patients were enrolled from May 2016 to May 2018 in Handan Central Hospital, China. All patients who participated in this study had been diagnosed with type 2 diabetes, according to the International Classification of Diseases (ICD-10). All participants underwent our survey, which included basic patient data and information about DFUs. The patients were followed for one year, during which time they received appropriate intervention from podiatrists, including lifestyle guidance, callus resection, tinea grinding and ingrown nail correction. At the end of the year all the patients were surveyed again. The data before and after the year were statistically compared. Results: The results showed that the incidence of DFUs in patients with diabetes was significantly decreased after one year of intervention from podiatrists (20.7% versus 6.7%, p<0.001). Additionally, there was a negative correlation between the number of intervention visits and the number of DFU occurrences (Spearman correlation coefficient: –0.496, p<0.001). Furthermore, we found that 68 patients with a history of DFUs or amputation had an obviously reduced incidence of DFUs after intervention by a podiatrist (89.7% versus 27.9%, p<0.001). We also investigated other foot risk factors in all participants, such as limb neuropathy (76.3%), lower extremity vascular disease (65.7%) and foot paralysis (43.7%). Conclusion: The results of this study help in understanding the situation of patients with diabetes in China and to prove that standardised podiatrist intervention has an important role in inhibiting the occurrence and development of DFUs. [ABSTRACT FROM AUTHOR]

Diabetic foot ulcers (DFUs) are associated with complex pathogenic factors and are considered a serious complication of diabetes. The potential mechanisms underlying DFUs have been increasingly investigated. Previous studies have focused on the three aspects of diabetic peripheral vascular disease, neuropathy, and wound infections. With advances in technology, researchers have been gradually conducting studies using immune cells, endothelial cells, keratinocytes, and fibroblasts, as they are involved in wound healing. It has been reported that the upregulation or downregulation of molecular signaling pathways is essential for the healing of DFUs. With a recent increase in the awareness of epigenetics, its regulatory role in wound healing has become a much sought‐after trend in the treatment of DFUs. This review focuses on four aspects involved in the pathogenesis of DFUs: physiological and pathological mechanisms, cellular mechanisms, molecular signaling pathway mechanisms, and epigenetics. Given the challenge in the treatment of DFUs, we are hopeful that our review will provide new ideas for peers. [ABSTRACT FROM AUTHOR]

Circular RNA (circRNA), a recently identified type of endogenous noncoding RNA, has been implicated in the occurrence and development of a variety of tumors; however, whether circ-SIRT1, derived from pre-mRNA of the parental SIRT1 gene, is involved in colorectal cancer (CRC) remains unknown, as do the potential underlying mechanisms. The expression of circ-SIRT1 in CRC cells and tissue was detected by RT-qPCR. Colony formation and Cell Counting Kit-8 assays were used to evaluate the effect of circ-SIRT1 knockdown on the proliferative ability of CRC cells. Wound healing and Transwell assays were used to assess the effect of circ-SIRT1 knockdown on the migratory and invasive capacity of CRC cells. RNA immunoprecipitation and RNA pull-down assays were employed to validate the binding of circ-SIRT1 to EIF4A3. Western blot was used to identify the changes in the expression of EIF4A3 and EMT-related proteins. The RT-qPCR results showed that circ-SIRT1 was highly expressed in CRC cells and tissue and was positively correlated with the depth of tumor invasion. Knocking down circ-SIRT1 inhibited the proliferation and invasion of CRC cells and EMT. We further found that EIF4A3 could bind to circ-SIRT1, and that overexpressing circ-SIRT1 decreased the abundance of EIF4A3 at the mRNAs of the EMT marker proteins N-cadherin and vimentin. Combined, our findings suggested that circ-SIRT1 regulates the expression of EMT-related proteins by preventing EIF4A3 recruitment to the respective mRNAs. Our results further indicate that circ-SIRT1 functions as an oncogene in CRC by promoting the proliferation, invasion, and EMT of CRC cells through the circ-SIRT1/EIF4A3/N-cadherin/vimentin pathway. [ABSTRACT FROM AUTHOR]

A sponge wound dressing comprising silk fibroin, N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride, and polyvinyl alcohol was developed for chronic wound healing. These composite sponges were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The composite sponge had a fluid uptake of 80% of its weight, and the water vapor transmission rate of 2974 ± 684 g/m2/day, indicating that the sponge could keep a moist environment around the wound bed. The Wistar rats were used to evaluate these composites for the treatment of chronic wounds. Wound healing was monitored through the macroscopic and immunological analyses. Although the wound area reduction rates were similar for the composite dressings compared to the non-woven fabrics containing wax-oil, the new composite dressings were found to be capable of improving the formation of blood vessels inside the wound beds by promoting the regrowth of skin tissues. Based on these results, using aqueous composite sponges in wound dressings, instead of oil-containing fabrics, promotes healing of chronic wounds in clinical applications. [ABSTRACT FROM AUTHOR]

The realization of coordinated infiltration of dermal and epidermal cell types, and the rapid deposition of extracellular matrix are the prerequisites for improved healing quality of large skin defects. However, presently used materials are limited for wound healing due to the inherent poor histocompatibility, low permeability, poor mechanical property and cytotoxicity. It is challenging to develop new therapeutic agents that enable timely and efficient wound healing and meanwhile there are minimal side effects to avoid chronic wounds, wound adhesions, and large scarring. Herein, we fabricated biomimetic exosomes (EMs) that enriched transforming growth factor β1 (TGF-β1) for the rapid healing of large-scale cutaneous wounds. The EM encapsulation allowed well-managed dosing of the TGF-β1 to effectively promote the wound healing process by endowing epidermal keratinocytes with a migratory feature, enhancing their stem cell properties, and resulting in accelerated in vivo wound re-epithelization. Specifically, the EMs could fast restore the function of sweat glands in a thermally injured mice model. Our work provides a promising strategy for improving the healing speed and healing quality for patients with large wounds. [Display omitted] • Biomimetic exosomes are developed for the rapid large-scale wound healing. • TGF-β1 is in situ induced and enhanced in the exosomes in a mild way. • Biomimetic exosomes promoted the restoration of functional sweat glands. • This work opens up a new sight in developing cell-free regenerative materials. [ABSTRACT FROM AUTHOR]