Stimulation of human vascular endothelial cell growth by a platelet-derived growth factor and thrombin

Repair of a vascular wound is mediated by migration and subsequent replication of the endothelial cells that form the inner lining of blood vessels. We have measured the growth response of human umbilical vein endothelial cells (HuE) to two polypeptides that are transiently produced in high concentrations at the site of a wound; the platelet-derived growth factor (PDGF) and the protease thrombin. When 10⁴ HuE cells are seeded as a dense island (2-mm diameter) in the center of a 16-mm tissue culture well in medium containing 20% human serum derived from platelet-poor plasma (PDS), no increase in cell number or colony size is observed. With the addition of 0.5 ng/ml partially purified PDGF, colony size increases and the number of cells after 8 days is 4.8 × 10⁴. When human thrombin (1 μg/ml) is added along with the PDGF, the cell number rises to 9.2 × 10⁴. Thrombin alone stimulates no increase in cell number. Although partially purified PDGF stimulates endothelial cells maintained in PDS as well as those maintained in whole blood serum (WBS), pure PDGF is active only when assayed in medium that contains WBS and is supplemented with thrombin. These results suggest the existence of a second class of platelet-derived factors that enable HuE cells to respond to the mitogenic activity of the purified platelet mitogen and thrombin.     

The wound response of the siphonous green algal genusCaulerpa III: Composition and origin of the wound plugs

Summary A complex, higly sulphated glucoxylomannogalactan has been extracted in a yield of about 1% dry weight fromC. simpliciuscula. This polysaccharide is similar in composition to sulphated polysaccharides previously isolated from otherCaulerpa species (Mackie andPercival, 1961). The most likely location of this compound in the unwounded cell is in the vacuole. This polysaccharide appears as the major component in wound plugs, forming a viscoelastic barrier between the protoplasm and the external environment. The properties of the sulphated polysaccharide were studied in an effort to understand the physiology and mechanism of wound plug formation.     

Creating Rigidly Stabilized Fractures for Assessing Intramembranous Ossification,Distraction Osteogenesis,or Healing of Critical Sized Defects

Assessing modes of skeletal repair is essential for developing therapies to be used clinically to treat fractures. Mechanical stability plays a large role in healing of bone injuries. In the worst-case scenario mechanical instability can lead to delayed or non-union in humans. However, motion can also stimulate the healing process. In fractures that have motion cartilage forms to stabilize the fracture bone ends, and this cartilage is gradually replaced by bone through recapitulation of the developmental process of endochondral ossification. In contrast, if a bone fracture is rigidly stabilized bone forms directly via intramembranous ossification. Clinically, both endochondral and intramembranous ossification occur simultaneously. To effectively replicate this process investigators insert a pin into the medullary canal of the fractured bone as described by Bonnarens⁴. This experimental method provides excellent lateral stability while allowing rotational instability to persist. However, our understanding of the mechanisms that regulate these two distinct processes can also be enhanced by experimentally isolating each of these processes. We have developed a stabilization protocol that provides rotational and lateral stabilization. In this model, intramembranous ossification is the only mode of healing that is observed, and healing parameters can be compared among different strains of genetically modified mice ^5-7, after application of bioactive molecules ^8,9, after altering physiological parameters of healing ¹⁰, after modifying the amount or time of stabilization ¹¹, after distraction osteogenesis ¹², after creation of a non-union ¹³, or after creation of a critical sized defect. Here, we illustrate how to apply the modified Ilizarov fixators for studying tibial fracture healing and distraction osteogenesis in mice.     

Regional differences in mitotic activity due to injury in mouse skin

Summary Mitotic activity adjacent to a wound inflicted at different sites in the mouse skin was measured 24 h after injury. A regional difference in the epidermal mitotic activity due to injury was noted. Mitotic activity was high in the anterior parts of the body including the head, lower in the middle to posterior regions of the body and lowest in the posterior-most parts of the body. Regional differences in epidermal mitotic activity due to injury were demonstrated in both female and male mice. The existence of a cranio-caudal gradient in epidermal response to injury is suggested.     

Mesenchymal stromal cell‐derived factors promote the colonization of collagen 3D scaffolds with human skin cells

The development of stem cell technology in combination with advances in biomaterials has opened new ways of producing engineered tissue substitutes. In this study, we investigated whether the therapeutic potential of an acellular porous scaffold made of type I collagen can be improved by the addition of a powerful trophic agent in the form of mesenchymal stromal cells conditioned medium (MSC‐CM) in order to be used as an acellular scaffold for skin wound healing treatment. Our experiments showed that MSC‐CM sustained the adherence of keratinocytes and fibroblasts as well as the proliferation of keratinocytes. Moreover, MSC‐CM had chemoattractant properties for keratinocytes and endothelial cells, attributable to the content of trophic and pro‐angiogenic factors. Also, for the dermal fibroblasts cultured on collagen scaffold in the presence of MSC‐CM versus serum control, the ratio between collagen III and I mRNAs increased by 2‐fold. Furthermore, the gene expression for α‐smooth muscle actin, tissue inhibitor of metalloproteinase‐1 and 2 and matrix metalloproteinase‐14 was significantly increased by approximately 2‐fold. In conclusion, factors existing in MSC‐CM improve the colonization of collagen 3D scaffolds, by sustaining the adherence and proliferation of keratinocytes and by inducing a pro‐healing phenotype in fibroblasts.     

基质金属蛋白酶9对糖尿病足溃疡愈合影响的研究进展

在糖尿病足患者溃疡创面分泌物中,基质金属蛋白酶9 (matrix metalloproteinase-9,MMP-9)过高是预测糖尿病足的发生及足溃疡难愈的主要指标,其可能的机制包括:高水平MMP-9降低VEGF的表达、抑制成纤维细胞的生物学行为影响糖尿病足溃疡愈合;失衡的MMP-9/TIMP-1比值影响糖尿病足溃疡愈合。选择性MMP-9抑制剂(包括小分子抑制剂、高级伤口辅料抑制剂、基于干扰基因水平表达的RNA抑制剂)可以作为促进糖尿病足溃疡愈合的手段,但仍需大样本、多中心随机对照试验以及长期随访进一步验证其疗效及安全性。现查阅近年来涉及MMP-9和糖尿病足溃疡相关的文献,综述MMP-9对糖尿病足溃疡愈合的影响及其机制研究进展。     

龙血竭胶囊合九华膏对环状混合痔术后患者创面愈合、血清炎性因子和免疫功能的影响

摘要 目的：探讨龙血竭胶囊合九华膏对环状混合痔（RMH）术后患者创面愈合、血清炎性因子和免疫功能的影响。方法：选取2016年7月~2019年12月期间我院收治的RMH患者93例,根据随机数字表法分为对照组（n=46,马应龙麝香痔疮膏治疗）和研究组（n=47,龙血竭胶囊合九华膏治疗）,比较两组患者疗效、创面愈合情况、不良反应、血清炎性因子和免疫功能。结果：治疗10 d后,研究组的临床总有效率为89.36%（42/47）,高于对照组的71.74%（33/46）（P<0.05）。两组治疗10 d后创面渗液、水肿、疼痛、创面肉芽组织评分下降,创面面积减小,且研究组低于对照组（P<0.05）。两组治疗10 d后肿瘤坏死因子-α（TNF-α）、白介素-6（IL-6）、白介素-2（IL-2）均下降,且研究组低于对照组（P<0.05）。两组治疗10 d后免疫球蛋白G（IgG）、免疫球蛋白A（IgA）、免疫球蛋白M（IgM）均升高,且研究组高于对照组（P<0.05）。研究组并发症发生率低于对照组（P<0.05）。结论：RMH患者术后采用龙血竭胶囊合九华膏治疗,疗效较好,可有效促进创面愈合,减轻炎症反应,改善机体免疫功能,同时还可减少并发症发生率。     

The cosmopolitics of flow and healing in north‐central Timor‐Leste

In north central Timor‐Leste, multi‐sensory ecological engagement is deeply entangled with conceptualisations of and approaches to people’s wellbeing. How people understand human health and wellbeing is closely related to how they understand nature or more particularly human/nature relations and distinctions across multiple timescales. Working through complex cosmopolitics and activated through cross‐temporal more‐than‐human ‘mutualities of being’, kinship networks are attuned to relational flows between ‘bodies’ and things. Rather than concentrating on the disjunctions created by the differences in the natures of beings or their ritual separation, this paper examines how relational flows between such ‘bodies’ and things open up cosmopolitical spaces for the creation and negotiation of intergenerational wellbeing.     

Umbilical cord-derived mesenchymal stem cells preconditioned with isorhamnetin: potential therapy for burn wounds

BACKGROUNDImpaired wound healing can be associated with different pathological states. Burn wounds are the most common and detrimental injuries and remain a major health issue worldwide. Mesenchymal stem cells (MSCs) possess the ability to regenerate tissues by secreting factors involved in promoting cell migration, proliferation and differentiation, while suppressing immune reactions. Preconditioning of MSCs with small molecules having cytoprotective properties can enhance the potential of these cells for their use in cell-based therapeutics.AIMTo enhance the therapeutic potential of MSCs by preconditioning them with isorhamnetin for second degree burn wounds in rats.METHODSHuman umbilical cord MSCs (hU-MSCs) were isolated and characterized by surface markers, CD105, vimentin and CD90. For preconditioning, hU-MSCs were treated with isorhamnetin after selection of the optimized concentration (5 µmol/L) by cytotoxicity analysis. The migration potential of these MSCs was analyzed by the in vitro scratch assay. The healing potential of normal, and preconditioned hU-MSCs was compared by transplanting these MSCs in a rat model of a second degree burn wound. Normal, and preconditioned MSCs (IH + MSCs) were transplanted after 72 h of burn injury and observed for 2 wk. Histological and gene expression analyses were performed on day 7 and 14 after cell transplantation to determine complete wound healing.RESULTSThe scratch assay analysis showed a significant reduction in the scratch area in the case of IH + MSCs compared to the normal untreated MSCs at 24 h, while complete closure of the scratch area was observed at 48 h. Histological analysis showed reduced inflammation, completely remodeled epidermis and dermis without scar formation and regeneration of hair follicles in the group that received IH + MSCs. Gene expression analysis was time dependent and more pronounced in the case of IH + MSCs. Interleukin (IL)-1β, IL-6 and Bcl-2 associated X genes showed significant downregulation, while transforming growth factor β, vascular endothelial growth factor, Bcl-2 and matrix metallopeptidase 9 showed significant upregulation compared to the burn wound, showing increased angiogenesis and reduced inflammation and apoptosis.CONCLUSIONPreconditioning of hU-MSCs with isorhamnetin decreases wound progression by reducing inflammation, and improving tissue architecture and wound healing. The study outcome is expected to lead to an improved cell-based therapeutic approach for burn wounds.     

Synthesis and characterization of silver nanoparticles decorated polydopamine coated hexagonal boron nitride and its effect on wound healing

BackgroundWound healing is an essential physiological process involving many cell types and their products acting in a marvellous harmony to repair damaged tissues. During the healing process, cellular proliferation and extracellular matrix remodelling stages could be interrupted by undesired factors including microorganisms and altered metabolic activities. In such a case, the process requires some external stimulants to accelerate or remediate the healing stages.MethodsIn this study, we report a multifunctional wound healing stimulating agent. In this context, hexagonal boron nitride (hBN) nanoparticles, silver nanoparticles (AgNPs) and polydopamine(pdopa) were used through mussel-inspired chemistry of dopamine to obtain pdopa coated hBN (hBN@pdopa) and AgNPs decorated hBN@pdopa (hBN@pdopa-AgNPs). These two nanostructures were investigated to observe stages of healing.ResultsAgNPs were chosen for inflammation reduction and hBN for induced cell proliferation and migration. In in vitro experiments, firstly, high cellular uptake capacity and biocompatibility of hBN@pdopa and hBN@pdopa-AgNPs were evaluated. They were also tested for their reaction against increased concentration of reactive oxygen species (ROS) in injured cells. Finally, their effect on cellular migration, intracellular tube formation and F-actin organization were monitored by light and confocal microscopy, respectively.ConclusionThe results clearly indicate that the hBN@pdopa-AgNPs significantly decrease ROS production, promote wound closure, and reorganize tube formation in cells.