Trauma-hemorrhage delays wound healing potentially by increasing pro-inflammatory cytokines at the wound site.

BACKGROUND: Studies indicate impaired wound healing after trauma. The underlying mechanism remains unknown. METHODS: Mice were subjected to midline laparotomy, and polyvinyl alcohol sponges were implanted subcutaneously before hemorrhage (35 +/- 5 mmHg for 90 minutes, resuscitated) or sham operation. Wound exudate cells from the sponges were harvested on the first, third, and fifth postoperative day and cultured for 24 hours. Interleukin (IL)-1 beta, IL-6, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-2 (MIP-2), and transforming growth factor (TGF)-beta were determined in the supernatants. IL-1 beta and IL-6 were measured in the wound fluid. RESULTS: Hemorrhage decreased collagen deposition in the wound. TGF-beta release was significantly decreased on the first and third postoperative days after hemorrhage, whereas IL-1 beta and IL-6 release was increased at 3 and 5 days after hemorrhage. Similarly, IL-1 beta and IL-6 in the wound fluid were significantly increased at 3 days after hemorrhage. CONCLUSIONS: Because increased levels of pro-inflammatory cytokines and decreased amounts of TGF-beta have been reported to impair the process of wound healing, the increased release of IL-1 beta and IL-6 and the decreased release of TGF-beta after hemorrhage might contribute to the decreased collagen production in those animals. Thus, attempts to locally change the ratio of those cytokines in trauma victims might be useful for improving wound healing in those patients.     

GHK‐Cu‐liposomes accelerate scald wound healing in mice by promoting cell proliferation and angiogenesis

Glycyl‐l ‐histidyl‐l ‐lysine (GHK)‐Cu is considered to be an activator of tissue remodeling, and has been used in cosmetic products. In this study, we prepared liposomes encapsulating GHK‐Cu and analyzed their effect on human umbilical vein endothelial cells (HUVECs) proliferation and scald wound healing in mice. The nanoscaled GHK‐Cu‐liposomes promoted HUVECs proliferation, with a 33.1% increased rate. Flow cytometry analysis showed increased cell number at G1 stage and decreased cell number at G2 stage after GHK‐Cu‐liposomes treatment. Western blotting indicated that the expression of vascular endothelial growth factor and fibroblast grow factors‐2 were both enhanced, as well as cell cycle‐related proteins CDK4 and CyclinD1. In a mice scald model, angiogenesis in burned skin treated with GHK‐Cu‐liposomes was better compared with free GHK‐Cu, and immunofluorescence analysis showed enhanced signal of CD31 and Ki67 in GHK‐Cu‐liposomes treated mice. Moreover, the wound healing time was shortened to 14 days post injury. Our results provide the evidence that GHK‐Cu‐liposomes could be utilized as a treatment for skin wounds.     

Simple wound care facilitates full healing in post-earthquake Haiti

The author provides an insight into the basic health care needs of two spinal cord injury patients who were cared for in a specially set up 25-bedded spinal cord injury unit in Haiti. While focusing on their extreme wound care requirements, the author highlights the need for adequate fluid, nutrition, hygiene and aseptic technique. Both patients were victims of the January 2010 earthquake in Port au Prince, Haiti. The author describes the basic wound care strategy for a patient with a category IV sacral pressure ulcer and another with a broken down thoracic spine surgical wound with visible metal work. This article describes how simple wound care effected the complete healing of large sacral pressure ulcers and broken down spinal surgical wounds without the need for further surgical intervention.     

维生素促进创面愈合的研究进展

创面愈合是一个复杂的病理生理过程,由多种细胞、生长因子等共同参与完成。维生素可以从不同方面、多个阶段对创面愈合起到促进作用。该文对维生素A、B、C、D、E在促进创面愈合中的作用及其相关机制的研究进展进行了综述。     

Erythropoietin stimulates wound healing and angiogenesis in mice.

Erythropoietin exerts hematopoietic effects by stimulating proliferation of early erythroid precursors. Nonhematopoietic effects of erythropoietin have also been shown. It may act as a new angiogenic factor in wound healing. This study aimed to investigate the effect of systemic administration of recombinant human erythropoietin on wound healing in mice. Dorsal incisional wounds were performed in mice, which were then divided into two groups; a group treated for 7 days with recombinant human erythropoietin, and a control group. Sacrificing animals on day 7, the wound tissues were collected for analysis of wound breaking strength, malondialdehyde, a marker of lipid peroxidation, hydroxyproline, an index of reparative collagen deposition, reduced glutathione levels, and for histological evaluation. The immunohistochemical determination of vascular endothelial growth factor (VEGF) which is believed to be the most prevalent angiogenic factor throughout the skin repair process, was also studied. The treatment significantly increased wound breaking strength by decreasing malondialdehyde and increasing hydroxyproline levels on day 7 after wounding. No statistically meaningful change was observed in reduced glutathione content. VEGF was immunostained significantly more on wound tissue of treated animals compared to the control group. Recombinant human erythropoietin treatment may be effective in wound healing due to inhibition of lipid peroxidation, deposition of collagen, and VEGF expression in wound area.     

胰岛素促创伤愈合的研究进展

自20世纪20年代加拿大年轻的生理学家班廷发现胰岛素后,糖尿病的治疗有了很好的控制。之后随着医学科学的发展和科研的进一步研究,人们发现胰岛素除了调节物质代谢外,还具有一定的抗炎作用及促修复细胞增殖、分化等作用。国内外诸多学者将胰岛素外用于创面,惊奇地发现胰岛素治疗组(与不治疗组比较)创面愈合时间明显缩短,愈合速度加快。本文就胰岛素促创伤愈合的可能机制作一综述。1胰岛素结构特性及促生长作用的发现胰岛素(insulin,INS)是一个分子量为56kD的酸性蛋白质,由A和B两条多肽链组成,A链有21个氨基酸残基,B链由30个氨基酸残基组…     

Dendritic cells modulate burn wound healing by enhancing early proliferation

Adequate wound healing is vital for burn patients to reduce the risk of infections and prolonged hospitalization. Dendritic cells (DCs) are antigen presenting cells that release cytokines and are central for the activation of innate and acquired immune responses. Studies have showed their presence in human burn wounds; however, their role in burn wound healing remains to be determined. This study investigated the role of DCs in modulating healing responses within the burn wound. A murine model of full‐thickness contact burns was used to study wound healing in the absence of DCs (CD11c promoter‐driven diphtheria toxin receptor transgenic mice) and in a DC‐rich environment (using fms‐like tyrosine kinase‐3 ligand, FL‐ a DC growth factor). Wound closure was significantly delayed in DC‐deficient mice and was associated with significant suppression of early cellular proliferation, granulation tissue formation, wound levels of TGFβ1 and formation of CD31⁺ vessels in healing wounds. In contrast, DC enhancement significantly accelerated early wound closure, associated with increased and accelerated cellular proliferation, granulation tissue formation, and increased TGFβ1 levels and CD31⁺ vessels in healing wounds. We conclude that DCs play an important role in the acceleration of early wound healing events, likely by secreting factors that trigger the proliferation of cells that mediate wound healing. Therefore, pharmacological enhancement of DCs may provide a therapeutic intervention to facilitate healing of burn wounds.     

A role for decorin in cutaneous wound healing and angiogenesis

Decorin is known to influence tissue tensile strength and cellular phenotype. Therefore, decorin is likely to have an impact on tissue repair, including cutaneous wound healing. In this study, cutaneous healing of both excisional and incisional full‐thickness dermal wounds was studied in decorin‐deficient (Dcn^?/?) animals. A statistically significant delay in excisional wound healing in the Dcn^?/? mice occurred at 4 and 10 days postwounding and, in incisional wounds at 4, 10, and 18 days when compared with wild‐type (Dcn^?/?) controls. Fibrovascular invasion into polyvinylalcohol sponges was significantly increased by day 18 in Dcn^?/? mice relative to Dcn^+/+ mice. The 18‐day sponge implants in the Dcn^?/? mice showed a marked accumulation of biglycan when compared with the corresponding implants in Dcn^+/+ mice. Thus, regulated production of decorin may serve as an excellent therapeutic approach for modifying impaired wound healing and harmful foreign body reactions.     

Potential molecular mechanisms of negative pressure in promoting wound healing

Negative pressure wound therapy (NPWT) has been widely used in various lesions. This study aimed to explore the biological effects of negative pressure on the polymorphonuclear neutrophils (PMNs), macrophages, and epidermal keratinocyte cells involved in wound healing. PMNs differentiated from HL‐60, macrophages were derived from THP‐1 monocytes, and keratinocytes were cultured in vitro, and they were treated with 0, ?0.03 mp, and ?0.05 mp, respectively. Cell ultrastructure; viability; apoptosis; and protein factors such as tumour necrosis factor‐α (TNF‐α), interferon‐γ (IFN‐γ), epidermal growth factor (EGF), epidermal growth factor receptor (EGFR), interleukin‐17 (IL‐17), and cell division cycle 42 (Cdc42) were determined by transmission electron microscopy (TEM), CCK8, flow cytometry (FCM), ELISA, and simple Western assays, respectively. After negative pressure stimulation, the cell ultrastructure of PMNs and macrophages cells was presented with a marked increase of lysosomes and a relative decrease of mitochondria. In addition, the cell viability was enhanced in PMNs and macrophages in a pressure‐dependent manner and apoptosis ratios were significantly reduced in PMNs and macrophages. In addition, under ?0.05 negative pressure, IFN‐γ and IL‐17 were significantly increased in PMNs or macrophages. Moreover, increased EGF and EGFR and Cdc42 levels in keratinocytes induced by the ?0.05 mpa were detected, indicating that the migration chemotaxis of keratinocyte cells was enhanced. Negative pressure might promote cell proliferation, accelerate inflammatory responses, and promote epithelialisation during wound healing by increasing IFN‐γ, IL‐17, Cdc42, EGF, and EGFR in PMNs, macrophages, or keratinocytes under different negative pressures.     

Age-dependent recruitment of neutrophils by fetal endothelial cells: implications in scarless wound healing

Purpose

Fetal dermal wounds heal with minimal inflammation and absent fibrosis. Later in gestation, a transition to adult-like healing with marked inflammation and scarring is observed. Interaction with endothelial cells (ECs) is imperative for leukocyte transmigration, a critical step in the inflammatory cascade. This study was embarked upon to determine if gestational age-dependent differences in EC function modulate changes in inflammatory response and correlate with the healing phenotype.

Methods

Fetal porcine ECs were harvested at days 65 (mid gestation), 85 (late gestation), and 100 (near-term) (term = 115 days). Confluent monolayers were activated with IL-1β at 10 and 100 ng/mL and exposed to adult neutrophils under static (n = 4 per group) and continuous flow (n = 6 per group) conditions. Neutrophil-endothelial interaction was quantified and compared using analysis of variance.

Results

Under static conditions, the lower cytokine dose elicited maximal neutrophil recruitment in later-gestation ECs, while midgestation ECs required higher stimulation. Midgestation ECs recruited significantly less neutrophils than later gestation ECs at both cytokine concentrations under flow conditions.

Conclusion

There is a gestational age-dependent variation in neutrophil recruitment by fetal ECs. With minimal stimulation, later-gestation ECs actively recruit neutrophils, whereas midgestation ECs do not. These findings correlate with the transition period to adult-like healing, supporting the potential role of fetal ECs in scarless healing.     

Anti-inflammatory treatment increases angiogenesis during early fracture healing

Objectives

Both inflammation and angiogenesis are crucial for normal fracture healing. The goal of this work was to determine how anti-inflammatory treatment affects angiogenesis during early stages of fracture repair.

Methods

Tibia fractures were created in adult mice and animals were treated with indomethacin (2?mg/kg/day), a non-steroidal anti-inflammatory drug, or PBS once a day beginning from 1 day before fracture and continuing to 6?days after fracture. Animals were killed at 7, 14, and 28?days after injury for histomorphometric analysis of fracture healing. A second group of animals were killed at 3 and 7?days after injury to measure tissue levels of VEGF and interleukin-1 beta (IL-1β). A third group of animals were killed at 3 and 7?days after injury for stereology analysis of macrophage and neutrophil infiltration and tissue vascularization.

Results

Indomethacin significantly decreased bone and cartilage formation at 7?days after fracture compared to controls. Indomethacin decreased the tissue levels of IL-1β at 3?days after fracture but did not affect the recruitment of macrophages or neutrophils to injured limbs. Indomethacin-treated fractures had similar length density and surface density of vasculature as the controls at 3?days after injury. At 7?days after fracture, vasculature in indomethacin-treated fractures exhibited higher length density and surface density than that in controls. By 28?days after injury, indomethacin-treated fractures still exhibited defects in fracture repair.

Conclusions

Anti-inflammatory treatments using indomethacin impair bone and cartilage formation and increase tissue vascularization in the callus during early fracture healing.     

Intracellular processing of epidermal growth factor by early wound healing cells

Epidermal growth factor (EGF) is a potent 53-amino-acid residue polypeptide that has been implicated in normal wound healing. Although past studies have shown that locally applied EGF accelerates wound healing, these studies have not examined intracellular events related to the processing of the growth factor. The objective of this study was to characterize both initial and later postbinding intracellular processing of EGF by a responsive cell line (osteoblasts) that is important in the healing of wounds. Cloned mouse calvarial osteoblasts (MC-3TC-E1) were incubated with radiolabeled EGF, with and without preincubation with nonlabeled EGF, for specific time intervals. Cell-associated radioactivity was characterized by nondenaturing polyacrylamide gel electrophoresis. Results showed that EGF is processed as three distinct species and that the relative proportions of these species are altered at later time periods when compared with initial processing. The patterns, similar to those reported for human fibroblasts, indicate a possible common pathway for the mitogenic signal in cells associated with the early events of wound healing. In addition, these data represent the first direct evidence that preexposure of cells to nonlabeled EGF alters the processing of radiolabeled EGF. This is significant, because cells must be exposed to EGF for 5 to 8 hours to elicit a growth response. Such data may help to explain the "lag phase" of wound healing.     

Local insulin-zinc injection accelerates skin donor site wound healing

BACKGROUND: Systemically administered insulin has been shown to accelerate wound healing. To minimize the hypoglycemic and hypokalemic effects of insulin, we investigated a new route of insulin administration by local injection into skin wounds. MATERIALS AND METHODS: Partial thickness skin donor site wounds were created on the backs of adult rabbits with a dermatome set at 0.015 inch. The wounds were covered by Aquaphor gauze (Smith and Nephew, Largo, FL), and OpSite membrane (Smith and Nephew, Hull, United Kingdom) and protected by rabbit jackets. Long-acting insulin-zinc suspension was selected for local injection. In study 1, insulin was injected into the wound at different doses, and the concentrations of blood glucose and wound insulin were measured to determine the proper dose and injection frequency. In study 2, wound healing days were compared between two groups (n = 7 each) receiving local injection of either insulin-zinc or zinc alone as control. Based on the results from study 1, a dose of 0.25 units of long-acting insulin-zinc suspension was injected into the wound every other day in the insulin group. RESULTS: After injection, 0.25 units of insulin decreased blood glucose concentration (minimum 60 mg/dL) during the first 3 h, which then returned to the preinjection level (80 mg/dL). One injection maintained wound insulin concentration above 50 muU/mL for more than 24 h. With local injection of 0.25 units insulin-zinc every other day, the wound healing time was 11.2 +/- 2.3 d, which was faster (P = 0.02) than 15.1 +/- 4.1 d in the control group. CONCLUSION: Local injection of long-acting insulin-zinc suspension accelerated skin wound healing without major systemic side effects, demonstrating its potential usefulness in burn treatment.     

LPS-pretreatment adipose-derived mesenchymal stromal cells promote wound healing in diabetic rats by improving angiogenesis

Mesenchymal stem cells (MSCs) play a key role in wound healing, and the advantages of pretreated MSCs in wound healing have previously been reported. In the present study, we investigated the impact of LPS pretreated human adipose-derived MSCs on skin wound healing in diabetic rats. We found that some improvements occurred through improving angiogenesis. Then, we scrutinized the impact of lipopolysaccharide (LPS) treatment on human adipose-derived MSCs in a high-glucose (HG) medium, as an in vitro diabetic model. In vivo findings revealed significant improvements in epithelialization and angiogenesis of diabetic wounds which received LPS pre-MSCs. Particularly, LPS pre-MSCs-treated diabetic wounds reached considerably higher percentages of wound closure. Also, the granulation tissue of these wounds had higher pronounced epithelialization and more vascularization compared with PBS-treated and MSCs-treated diabetic ones by CD31, VEGF, CD90, collagen 1, and collagen 3 immunostaining. Western-blots analyses indicated that LPS pre-MSCs led to the upregulation of vascular endothelial growth factor (VEGF) and DNMT1. In addition, significantly higher cell viability (proliferation/colonie), and elevated VEGF and DNMT1 protein expression were observed when MSCs were treated with LPS (10 ng/ml, 6 h) in HG culture media. Based on these findings, it is suggested that LPS pre-MSCs could promote wound repair and skin regeneration, in some major processes, via the improvement of cellular behaviors of MSCs in the diabetic microenvironment. The beneficial advantages of LPS treated with mesenchymal stem cells on wound healing may lead to establishing a novel approach as an alternative therapeutic procedure to cure chronic wounds in diabetic conditions.     

Activation of mitosis and angiogenesis in diabetes-impaired wound healing by processed human amniotic fluid

Background

Functional characterization of human amniotic fluid (AF) proteome, 845 proteins, has revealed that top three functions are cell proliferation, movement and differentiation, events fundamental to development, and tissue repair. Although these findings fortify the idea that AF components play roles in regeneration-like fetal wound healing, it is not known whether the components endure processing. Therefore, we processed AF and tested its effects on diabetes-impaired wound healing in an animal model.

Materials and methods

Through a germfree procedure, mature and premature AF samples were collected, respectively, from the mothers of full-term and preterm infants. Excisional wounds were generated on the dorsum of diabetic rats. Wounds were treated on day 3 and harvested on day 7 postwounding. Proliferating cell nuclear antigen and alpha–smooth muscles actin, markers for mitosis and angiogenesis, respectively, were assessed by in situ immunodetection method.

Results

Significant increases in the rate of wound closure and proliferating cell nuclear antigen–expressing cells were observed in AF-treated wounds when compared with that of sham and control wounds. Likewise, the number of large vessels was significantly increased in the wounds treated with the AF. However, population of myofibroblasts was not affected by the treatment. The mature and premature AF were almost equally effective.

Conclusions

Our data, for the first time, show that processed AF accelerates diabetes-impaired wound healing by activating mitosis and angiogenesis, indicating that bioactive molecules in AF may endure processing. We believe that processed forms of this naturally designed “Cocktail” of bioactive molecules may have multiple clinical applications.     

Expression of Wnt genes in early wound healing

The Wnt family of developmental genes has previously been shown to be involved in proliferation, differentiation, and cell to cell signaling during embryogenesis. In addition, several Wnt genes have been shown to be expressed during carcinogenesis. We have investigated these genes during the wound-healing process. Wnt-4 gene expression is found in mouse wounds from 2 hours to 30 hours postwounding. The expression of Wnt-4 is also stimulated by direct trauma to murine fibroblasts in culture, and the expression is greatly enhanced by the addition of a short plasmin digest of fibrin. Therefore the regulation of Wnt-4 , appears to be complex, with expression being stimulated both by direct trauma and by the influence of clotting and fibrinolysis products. We propose that the expression of Wnt-4 in the early wound, in response to the provisional fibrin matrix, regulates cell movement and proliferation in the creation of new tissue by mechanisms related to those of embryogenesis.     

Polydeoxyribonucleotide stimulates angiogenesis and wound healing in the genetically diabetic mouse

Healing of diabetic wounds still remains a critical medical problem. Polydeoxyribonucleotide (PDRN), a compound having a mixture of deoxyribonucleotide polymers, stimulates the A2 purinergic receptor with no toxic or adverse effect. We studied the effects of PDRN in diabetes‐related healing defect using an incisional skin‐wound model produced on the back of female diabetic mice (db+/db+) and their normal littermates (db+/+m). Animals were treated daily for 12 days with PDRN (8 mg/kg/ip) or its vehicle (100 μL 0.9%NaCl). Mice were killed 3, 6, and 12 days after skin injury to measure vascular endothelial growth factor (VEGF) mRNA expression and protein synthesis, to assay angiogenesis and tissue remodeling through histological evaluation, and to study CD31, Angiopoietin‐1 and Transglutaminase‐II. Furthermore, we measured wound breaking strength at day 12. PDRN injection in diabetic mice resulted in an increased VEGF message (vehicle=1.0±0.2 n‐fold vs. β‐actin; PDRN=1.5±0.09 n‐fold vs. β‐actin) and protein wound content on day 6 (vehicle=0.3±0.07 pg/wound; PDRN=0.9±0.1 pg/wound). PDRN injection improved the impaired wound healing and increased the wound‐breaking strength in diabetic mice. PDRN also caused a marked increase in CD31 immunostaining and induced Transglutaminase‐II and Angiopoietin‐1 expression. Furthermore, the concomitant administration of 3,7‐dimethyl‐1‐propargilxanthine, a selective adenosine A2A receptor antagonist, abolished PDRN positive effects on healing. However, 3,7‐dimethyl‐1‐propargilxanthine alone did not affect wound healing in both diabetic mice and normal littermates. These results suggest that PDRN might be useful in wound disorders associated with diabetes.