OxymiRs in cutaneous development,wound repair and regeneration

The state of tissue oxygenation is widely recognized as a major microenvironmental cue that is known to regulate the expression of coding genes. Recent works have extended that knowledge to demonstrate that the state of tissue oxygenation may potently regulate the expression of microRNAs (miRs). Collectively, such miRs that are implicated in defining biological outcomes in response to a change in the state of tissue oxygenation may be referred to as oxymiRs. Broadly, oxymiRs may be categorized into three groups: (A) the existence (expression and/or turnover) of which is directly influenced by changes in the state of tissue oxygenation; (B) the existence of which is indirectly (e.g. oxygen-sensitive proteins, metabolites, pH, etc.) influenced by changes in the state of tissue oxygenation; and (C) those that modify biological outcomes to changes in the state of tissue oxygenation by targeting oxygen sensing pathways. This work represents the first review of how oxymiRs may regulate development, repair and regeneration. Currently known oxymiRs may affect the functioning of a large number of coding genes which have hitherto fore never been linked to oxygen sensing. Many of such target genes have been validated and that number is steadily growing. Taken together, our understanding of oxymiRs has vastly expanded the implications of changes in the state of tissue oxygenation. This emerging paradigm has major implications in untangling the complexities underlying diseases associated with ischemia and related hypoxic insult such as chronic wounds.     

Syndecans in wound healing, inflammation and vascular biology

Syndecans are heparan sulphate proteoglycans consisting of a type I transmembrane core protein modified by heparan sulphate and sometimes chondroitin sulphate chains. They are major proteoglycans of many organs including the vasculature, along with glypicans and matrix proteoglycans. Heparan sulphate chains have potential to interact with a wide array of ligands, including many growth factors, cytokines, chemokines and extracellular matrix molecules relevant to growth regulation in vascular repair, hypoxia, angiogenesis and immune cell function. This is consistent with the phenotypes of syndecan knock-out mice, which while viable and fertile, show deficits in tissue repair. Furthermore, there are potentially important changes in syndecan distribution and function described in a variety of human vascular diseases. The purpose of this review is to describe syndecan structure and function, consider the role of syndecan core proteins in transmembrane signalling and also their roles as co-receptors with other major classes of cell surface molecules. Current debates include potential redundancy between syndecan family members, the significance of multiple heparan sulphate interactions, regulation of the cytoskeleton and cell behaviour and the switch between promoter and inhibitor of important cell functions, resulting from protease-mediated shedding of syndecan ectodomains.     

Roles of wound geometry, wound size, and extracellular matrix in the healing response of bovine corneal endothelial cells in culture

It has classically been accepted that the healing of narrow wounds in epithelia occurs by the formation of a contractile actin cable, while wide wounds are resurfaced by lamellipodia-dependent migration of border cells into the denuded area. To further investigate the general validity of this idea, we performed systematic experiments of the roles of wound geometry, wound size, and extracellular matrix (ECM) in wound healing in monolayers of bovine corneal endothelial cells, a system shown here to predominantly display any of the two healing mechanisms according to the experimental conditions. We found that, in this system, it is the absence or presence of the ECM on the wound surface that determines the specific healing mode. Our observations demonstrate that, independent of their size and geometry, wounds created maintaining the ECM heal by migration of cells into the wound area, while ECM removal from the wound surface determines the predominant formation of an actin cable. While the latter mechanism is slower, the actin cable permits the maintainance of the epithelial phenotype to a larger extent during the healing process, as also confirmed by our finding of a more conserved localization of cadherin and vinculin. We also introduce a model that simulates experimental findings about the dynamics of healing mechanisms, both for the maintenance or removal of the ECM on the wound surface. The findings of this study may contribute to the understanding of physiological and pathological aspects of epithelial wound healing and to the design of therapeutic strategies.     

The lacrimal gland: development,wound repair and regeneration

The lacrimal gland (LG) is important as it has a significant role in maintaining the stability of the microenvironment of the ocular surface. When a loss of function occurs in the LG, a significant reduction in tear production and dry eye disease (DED) may occur. A mammalian LG is a secretory gland consisting of acini and ducts. The interaction between epithelial cells and mesenchymal cells plays a major role during development and the self-restoration process of the gland. Some factors, such as fibroblast growth factor 10 and bone morphogenetic protein 7, are associated with these processes. Though several strategies for LG regeneration have been established, there is still a long way to go before there is clarity about LG stem cells. In this review, current knowledge on LG development, LG self-repair, DED and correlative regeneration therapies are summarized.     

老年难愈性创面患者临床特征及创面细菌学分析

目的 分析老年难愈性创面患者的临床特征、创面细菌学及疗效,为临床治疗提供参考依据。方法 回顾性分析我科2012年1月至2017年12月收治的114例老年难愈性创面患者的临床资料。对患者合并内科基础疾病、生理机能状况、创面病因和部位、创面分泌物细菌和多重耐药菌分布、创面治疗效果等进行分析。结果 患者常见内科基础疾病有高血压（63例）、糖尿病（42例）、脑血管疾病（38例）和心脏病（31例）,常见生理指标异常为白蛋白降低（89例）和贫血（70例）。本组共有186处创面（37例患者有1个以上创面）,常见病因为烧伤（44.62%）、压迫（35.48%）,常见病变部位为下肢（67.74%）。创面分离出病原菌113株,革兰阴性菌占71.68%。常见菌为铜绿假单胞菌（35.40%）、金黄色葡萄球菌（25.66%）、大肠埃希菌（12.39%）。多重耐药菌检出率为71.68%（81/113）。本组创面的治疗效果为：治愈94处、好转64处、未愈28处。38.17%创面进行了手术治疗。手术治疗的疗效为治愈58处、好转10处、未愈3处,明显优于非手术治疗（Z= -6.478,P=0.000）。结论 老年难愈性创面患者合并内科基础病多、生理机能状况差,创面细菌以革兰阴性球菌为主、多重耐药菌比例高,创面治疗效果偏差,手术比例低,但手术治疗取得了较好疗效。     

Development and application of a polymicrobial, in vitro, wound biofilm model

Aims: The goal of this investigation was to develop an in vitro, polymicrobial, wound biofilm capable of supporting the growth of bacteria with variable oxygen requirements. Methods and Results: The strict anaerobe Clostridium perfringens was isolated by cultivating wound homogenates using the drip‐flow reactor (DFR), and a three‐species biofilm model was established using methicillin‐resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Cl. perfringens in the colony‐drip‐flow reactor model. Plate counts revealed that MRSA, Ps. aeruginosa and Cl. perfringens grew to 7·39 ± 0·45, 10·22 ± 0·22 and 7·13 ± 0·77 log CFU per membrane, respectively. The three‐species model was employed to evaluate the efficacy of two antimicrobial dressings, Curity? AMD and Acticoat?, compared to sterile gauze controls. Microbial growth on Curity? AMD and gauze was not significantly different, for any species, whereas Acticoat? was found to significantly reduce growth for all three species. Conclusions: Using the colony‐DFR, a three‐species biofilm was successfully grown, and the biofilms displayed a unique structure consisting of distinct layers that appeared to be inhabited exclusively or predominantly by a single species. Significance and Impact of the Study: The primary accomplishment of this study was the isolation and growth of an obligate anaerobe in an in vitro model without establishing an artificially anaerobic environment.     

巨噬细胞与创伤愈合

巨噬细胞是创伤愈合过程中一系列复杂反应中的关键环节,它调节成纤维细胞和血管内皮细胞的生物学活性,在创伤愈合过程中占有不可替代的作用。加强巨噬细胞功能和应用细胞因匀能有效地促进创伤愈合。     

瘦素与创伤愈合

瘦素作为一种多靶器官、多功能的生长因子,它在机体中具有广泛的生理作用。瘦素可能是一种新的促创伤愈合因子,它参与了创伤愈合进程的调节,腹膜内注射瘦素或局部涂抹瘦素加速了动物伤口愈合的速度。本文主要综述了近年来瘦素促进伤口愈合作用的研究现状,并从瘦素在伤口愈合过程中对上皮再生、胶原合成、血管生成、炎症反应等几方面的作用,探讨了瘦素通过调控其它促创伤愈合因子的生成及活性来发挥促伤口愈合作用的机制与途径。     

Fibronectin and wound healing

I have tried to briefly review the evidence (summarized in Table II) indicating that fibronectin is important in cutaneous wound healing. Fibronectin appears to be an important factor throughout this process. It promotes the spreading of platelets at the site of injury, the adhesion and migration of neutrophils, monocytes, fibroblasts, and endothelial cells into the wound region, and the migration of epidermal cells through the granulation tissue. At the level of matrix synthesis, fibronectin appears to be involved both in the organization of the granulation tissue and basement membrane. In terms of tissue remodeling, fibronectin functions as a nonimmune opsonin for phagocytosis of debris by fibroblasts, keratinocytes, and under some circumstances, macrophages. Fibronectin also enhances the phagocytosis of immune-opsonized particles by monocytes, but whether this includes phagocytosis of bacteria remains to be determined. In general, phagocytosis of bacteria has not appeared to involve fibronectin. On the contrary, the presence of fibronectin in the wound bed may promote bacterial attachment and infection. Because of the ease of experimental manipulations, wound healing experiments have been carried out on skin more frequently than other tissues. As a result, the possible role of fibronectin has not been investigated thoroughly in the repair of internal organs and tissues. Nevertheless, it seems reasonable to speculate that fibronectin plays a central role in all wound healing situations. Finally, the wound healing problems of patients with severe factor XIII deficiencies may occur because of their inability to incorporate fibronectin into blood clots.     

Innate defense regulator Peptide 1018 in wound healing and wound infection

Innate defense regulators (IDRs) are synthetic immunomodulatory versions of natural host defense peptides (HDP). IDRs mediate protection against bacterial challenge in the absence of direct antimicrobial activity, representing a novel approach to anti-infective and anti-inflammatory therapy. Previously, we reported that IDR-1018 selectively induced chemokine responses and suppressed pro-inflammatory responses. As there has been an increasing appreciation for the ability of HDPs to modulate complex immune processes, including wound healing, we characterized the wound healing activities of IDR-1018 in vitro. Further, we investigated the efficacy of IDR-1018 in diabetic and non-diabetic wound healing models. In all experiments, IDR-1018 was compared to the human HDP LL-37 and HDP-derived wound healing peptide HB-107. IDR-1018 was significantly less cytotoxic in vitro as compared to either LL-37 or HB-107. Furthermore, administration of IDR-1018 resulted in a dose-dependent increase in fibroblast cellular respiration. In vivo, IDR-1018 demonstrated significantly accelerated wound healing in S. aureus infected porcine and non-diabetic but not in diabetic murine wounds. However, no significant differences in bacterial colonization were observed. Our investigation demonstrates that in addition to previously reported immunomodulatory activities IDR-1018 promotes wound healing independent of direct antibacterial activity. Interestingly, these effects were not observed in diabetic wounds. It is anticipated that the wound healing activities of IDR-1018 can be attributed to modulation of host immune pathways that are suppressed in diabetic wounds and provide further evidence of the multiple immunomodulatory activities of IDR-1018.     

Wound currents and wound healing in the newt,Notophthalmus viridescens

Summary Wounded amphibian skin heals initially by a migration of epithelial cells from the cut edge towards the center of the wound. The density of currents leaving wounds made in Notophthalmus viridescens skin was manipulated in order to determine whether electrical fields associated with these currents might have a significant role in promoting this cell migration during wound healing. Wounds were made with either a needle (200 m) or a biopsy punch (500 m). Currents leaving the wounds were measured with a vibrating probe, and the wounds fixed at various times after wounding. When the Na⁺-dependent currents were reduced by blocking Na⁺ channels with benzamil, wound healing, as revealed by scanning electron microscopy and by paraffin histology, was impaired. These results are consistent with the hypothesis that there is an electrical component to wound healing.     

A high throughput, interactive imaging, bright-field wound healing assay

The wound healing assay is a commonly used technique to measure cell motility and migration. Traditional methods of performing the wound healing assay suffer from low throughput and a lack of quantitative data analysis. We have developed a new method to perform a high-throughput wound healing assay that produces quantitative data using the LEAP? instrument. The LEAP? instrument is used to create reproducible wounds in each well of a 96-well plate by laser ablation. The LEAP? then records bright field images of each well at several time points. A custom texture segmentation algorithm is used to determine the wound area of each well at each time point. This texture segmentation analysis can provide faster and more accurate image analysis than traditional methods. Experimental results show that reproducible wounds are created by laser ablation with a wound area that varies by less than 10%. This method was tested by confirming that neuregulin-2β increases the rate of wound healing by MCF7 cells in a dose dependent manner. This automated wound healing assay has greatly improved the speed and accuracy, making it a suitable high-throughput method for drug screening.     

Synthesis,characterization, and wound healing properties of α/γ hybrid peptides

The present work describes the synthesis, characterization, and wound healing properties of α/γ hybrid peptides: Boc-Phe-γ⁴-Phe-Val-OMe ( S1 ), Boc-^DPhe-γ⁴-Phe-Val-OMe ( S2 ), Boc-Ala-γ⁴-Phe-Val-OMe ( S3 ), Boc-^DAla-γ⁴-Phe-Val-OMe ( S4 ), Boc-Leu-γ⁴-Phe-Val-OMe ( S5 ), and Boc-^DLeu-γ⁴-Phe-Val-OMe ( S6 ). Peptides S1–S6 were screened against human keratinocytes (HaCaT) and RAW 264.7 cells. Among all, S1 - and S2 -treated cells exhibited high cell viability; S1 and S2 induced keratinocyte migration and inhibited the production of the cytokines IL-6 and TNF-α. In vivo results demonstrated that the hybrid peptides S1 and S2 accelerate wound healing in Wistar rats with 83% and 88% at 50 μg/ml, and 74% and 76% at 25 μg/ml, respectively.