Hydrogen peroxide disrupts scarless fetal wound repair

Wound healing in db/db mice with type 2 diabetes using non-contact exposure with an argon non-thermal atmospheric pressure plasma jet device

A non-thermal atmospheric pressure plasma jet (APPJ) may stimulate cells and tissues or result in cell death depending on the intensity of plasma at the target; therefore, we herein investigated the effects of non-thermal plasma under non-contact conditions on the healing of full-thickness wounds in diabetic mice (DM+ group) and normal mice (DM- group). A hydrogen peroxide colorimetric method and high performance liquid chromatography showed that APPJ produced low amounts of reactive oxygen and nitrogen species. Ten-week-old male C57BL/6j mice with normal blood glucose levels (DM- group) and 10-week-old male C57BLKS/J Iar-+Leprdb/+Leprdb mice (DM+ group) received two full-thickness cutaneous wounds (4 mm in diameter) on both sides of the dorsum. Wounds were treated with or without the plasma jet or argon gas for 1 minute and were then covered with a hydrocolloid dressing (Hydrocolloid), according to which mice were divided into the following groups: DM+Plasma, DM+Argon, DM+Hydrocolloid, DM-Plasma, DM-Argon, and DM-Hydrocolloid. Exudate weights, wound areas, and wound area ratios were recorded every day. Hematoxylin and eosin staining was performed to assess re-epithelialization and α-SMA immunohistological staining to evaluate the formation of new blood vessels. Non-thermal plasma under non-contact conditions reduced the production of exudate. Exudate weights were smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups. The wound area ratio was smaller for plasma-treated wounds, and was also smaller in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups on days 1-21 (p<0.01). Wound areas were smaller in the DM-Plasma group than in the DM-Argon group until day 14 and differences were significant on days 1-5 (p<0.01). The percentage of re-epithelialization was significantly higher in the DM+Plasma group than in the DM+Argon and DM+Hydrocolloid groups (p<0.01). The number of new blood vessels that had formed by day 7 was significantly higher in the DM+Plasma group than in the DM+Hydrocolloid and DM+Argon groups (p<0.05). These results indicate that treatment with the current non-thermal plasma APPJ device under non-contact conditions accelerated wound healing in diabetic mice.

The effects of mouthwashes in human gingiva epithelial progenitor (HGEPp) cells

OBJECTIVES

The gingiva epithelium accounts for a significant proportion of the surface around the tooth. An inflammatory reaction occurs in the presence of bacterial biofilm, adhesion is reduced, and the depth of the sulcus gingivalis increases. The most common antiseptic agents in oral rinses are chlorhexidine digluconate (CHX) and cetylpyridinium chloride. We examined long-lasting effects of residual concentrations of eight commercially available rinses. Our main goals were (i) to analyze the effect of different chemical compositions on cell proliferation, (ii) to examine apoptosis, and (iii) cell morphology on human epithelial progenitor cell line (HGEPp).

MATERIALS AND METHODS

Cell proliferation was measured in a real-time system (0-48 h) by impedimetry (xCELLigence). Apoptosis was measured with labeled Annexin-V (BD-FACScalibur).

RESULTS

Changes in proliferation were measured at certain concentrations: (i) H₂O₂ proved to be cytotoxic at almost all concentrations; (ii) low concentrations of CHX (0.0001%; 0.0003%) were proliferation inducers, while higher concentrations were cytotoxic; (iii) for ClO₂, advantageous proliferative effect was observed over a broad concentration range (0.06-6 ppm). In mouthwashes, additives in the formulation (e.g., allantoin) appeared to influence cellular responses positively. Apoptosis marker assay results suggested a low-level activation by the tested agents.

CONCLUSIONS

Mouthwashes and their reference compounds proved to have concentration-dependent cytotoxic effects on human gingival epithelial cells.

CLINICAL RELEVANCE

A better understanding of the effects of mouthwashes and their reference compounds is particularly important. These concentration-dependent effects (cytotoxic or proliferation inducing) interfere with human cells physiology while being used in the fight against the pathogenic flora.

Hydrogen Peroxide: Its Use in an Extensive Acute Wound to Promote Wound Granulation and Infection Control - Is it Better Than Normal Saline?

Background: Hydrogen peroxide (H₂O₂) is used as a topical antiseptic in contaminated wounds caused by road traffic accidents. It kills bacteria by producing oxidation through local, nascent, free oxygen radicals. It also removes dirt from the wound due to its frothing action. H₂O₂ is synthesized by various cells as an active biochemical agent that affects cell biological behavior through complex chemical reactions. H₂O₂ has also been used as a wound cleaning agent, removing debris, preventing infection, and causing hemostasis due to its exothermic reaction with blood. Despite its widespread use, there is scanty literature on its use to promote granulation tissue formation. Objective: In the orthopaedics literature, studies on H₂O₂ use are very limited and its potential is underestimated. In the present study, we would like to report our protocol of use of H₂O₂ for its tremendous potential for stimulating granulation and early wound healing. Material and Methods: A total of 53 patients with large acute extensive lower limb contaminated wounds reported to the emergency department have been included with and without lower limb fracture. In group A (43 patients) wound management was done using 7% H₂O₂ and group B (10 patients) was treated by only saline dressing as a control group. Results: In the present study, daily dressing by 7% H₂O₂ solution and provide solution gives excellent results compared to the Saline group. Granulation tissue appeared much earlier with a mean SD 6.3 ± 6.8 days in the hydrogen peroxide group as compared to the Saline group where granulation tissue appeared in 9.3 ± 8.4 days. Conclusion: Spontaneous wound healing is a controlled balance between destructive and healing processes. It is mandatory to remove damaged tissue to promote healing by secondary intention and minimize infection. The dynamic effect of H₂O₂ promotes faster healing, stimulates granulation, and minimizes infection by oxidative stress.

Role of hydrogen peroxide in intra-operative wound preparation based on an in vitro fibrin clot degradation model

Three per cent hydrogen peroxide (H₂O₂) is widely used to irrigate acute and chronic wounds in the surgical setting and clinical experience tells us that it is more effective at removing dried-on blood than normal saline alone. We hypothesise that this is due to the effect of H₂O₂ on fibrin clot architecture via fibrinolysis. We investigate the mechanisms and discuss the clinical implications using an in vitro model. Coagulation assays with normal saline (NaCl), 1% and 3% concentrations of H₂O₂ were performed to determine the effect on fibrin clot formation. These effects were confirmed by spectrophotometry. The effects of 1%, 3% and 10% H₂O₂ on the macroscopic and microscopic features of fibrin clots were assessed at set time intervals and compared to a NaCl control. Quantitative analysis of fibrin networks was undertaken to determine the fibre length, diameter, branch point density and pore size. Fibrin clots immersed in 1%, 3% and 10% H₂O₂ demonstrated volume losses of 0.09-0.25mm³/min, whereas those immersed in the normal saline gained in volume by 0.02±0.13 mm³/min. Quantitative analysis showed that H₂O₂ affects the structure of the fibrin clot in a concentration-dependent manner, with the increase in fibre length, diameter and consequently pore sizes. Our results support our hypothesis that the efficacy of H₂O₂ in cleaning blood from wounds is enhanced by its effects on fibrin clot architecture in a concentration- and time-dependent manner. The observed changes in fibre size and branch point density suggest that H₂O₂ is acting on the quaternary structure of the fibrin clot, most likely via its effect on cross-linking of the fibrin monomers and may therefore be of benefit for the removal of other fibrin-dependent structures such as wound slough.

A Murine Incisional Fetal Wound-Healing Model to Study Scarless and Fibrotic Skin Repair

The ideal response to skin injury is the complete regeneration of normal tissue without scar formation. This regenerative response is known to occur at early stages of embryonic development but is lost as the skin becomes more mature. In more developed skin, the wound-healing response is suboptimal and results in the formation of scar tissue. Scar tissue can be a significant clinical concern, causing skin dysfunction as well as psychosocial issues related to poor aesthetic outcomes. Mouse models of fetal wound healing can be useful for understanding what regulatory pathways lead to skin regeneration and scarless healing in less developed skin or scarring and fibrotic healing in more developed skin. Here, a reproducible incisional wound model in developing mice is described that our lab has used repeatedly to study scarless and fibrotic fetal wound healing.

Formulation of a reactive oxygen producing calcium sulphate cement as an anti-bacterial hard tissue scaffold

Prophylactic antibiotic bone cements are extensively used in orthopaedics. However, the development of antimicrobial resistance to antibiotics, demonstrates a need to find alternative treatments. Herein, an antimicrobial honey (SurgihoneyRO-SHRO) has been successfully incorporated into a calcium sulphate (CS) based cement to produce a hard tissue scaffold with the ability to inhibit bacterial growth. Antimicrobial properties elicited from SHRO are predominantly owed to the water-initiated production of reactive oxygen species (ROS). As an alternative to initially loading CS cement with SHRO, in order to prevent premature activation, SHRO was added into the already developing cement matrix, locking available water into the CS crystal structure before SHRO addition. Promisingly, this methodology produced > 2.5 times (715.0 ± 147.3 μM/mL/g) more ROS over 24 h and exhibited a compressive strength (32.2 ± 5.8 MPa) comparable to trabecular bone after 3 weeks of immersion. In-vitro the SHRO loaded CS scaffolds were shown to inhibit growth of clinically relevant organisms, Staphylococcus aureus and Pseudomonas aeruginosa, with comparable potency to equivalent doses of gentamicin. Encouragingly, formulations did not inhibit wound healing or induce an inflammatory response from osteoblasts. Overall this study highlights the prophylactic potential of CS-SHRO cements as an alternative to traditional antibiotics.

Formulation of an antimicrobial superabsorbent powder that gels in situ to produce reactive oxygen

The enzymatic oxidation of glucose to produce reactive oxygen species (ROS) provides honey with antimicrobial efficacy. This mechanism offers an alternative to traditional antibiotics; however, topical use of honey is limited due to its adherent and highly viscous properties. This study aims to overcome these issues by engineering a powder-based system that eases delivery and offers in situ activation of ROS. Starch based drying agents were utilised to enable freeze drying of a medical honey, with methylated-β-cyclodextrin (MCD) enabling the highest active incorporation (70%) while still producing a free-flowing powder. Addition of a superabsorbent, sodium polyacrylate (≤40%) was shown to facilitate in situ gelation of the powder, with an absorption capacity of up to 120.7 ± 4.5 mL g^-1. Promisingly efficacy of the optimised superabsorbent powder was demonstrated in vitro against several clinically relevant Gram-negative and Gram-positive bacteria (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa). Alongside this no adverse effects were observed against human dermal fibroblasts. Application of the superabsorbent powder in an ex-vivo porcine wound model revealed capability to form a protective hydrogel barrier in less than 1 min. Overall, this novel ROS producing superabsorbent powder has potential to tackle topical infections without using traditional antibiotics.

The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions

INTRODUCTION

The Mulcahy salvage fundamentally altered the management of penile prosthesis infections (PPI). Central to this procedure is a sequence of antiseptic irrigations that aims to remove and eradicate pathogenic microflora from the infected field, thus preparing for immediate reimplantation. The antiseptic solutions and their respective concentrations, however, have never been evaluated for efficacy.

AIM

This review critically examines 3 commonly used antiseptic irrigation solutions (povidone-iodine [PVI], hydrogen peroxide [H₂O₂], and chlorhexidine gluconate [CHG]) in terms of their antimicrobial activity, cytotoxicity, and clinical use.

METHODS

A PubMed literature review was performed on articles published between 2003 and 2018. Both preclinical as well as clinical studies from various surgical disciplines were included in this review.

MAIN OUTCOME MEASURE

The original salvage protocol selected for irrigation solutions at concentrations that are likely detrimental to native tissue.

RESULTS

All 3 agents demonstrate in vitro cytotoxic effects at subclinical concentrations, but H₂O₂ is associated with the most significant deleterious properties. It does not seem to broaden antimicrobial coverage beyond what is covered by PVI. Dilute PVI (0.35-3.5% with exposure time of at least 3 minutes) possesses the most robust clinical evidence as an intraoperative adjunct, reducing the incidence of postoperative infectious complications. chlorhexidine gluconate is a promising new agent but lacks clinical data.

CLINICAL IMPLICATION

Improvements in the salvage protocol are warranted based on current evidence. Careful selection of lavage solution and usage of the lowest necessary concentration will help achieve desired antimicrobial activity while avoiding native tissue cytotoxicity. Strength and limitation: The study is limited by its retrospective nature, and the heterogeneity of literature reviewed precluded a formal meta-analysis. Furthermore, future studies will need to address the roles of normal saline and antibiotic irrigations as intraoperative adjuncts for infection prevention.

CONCLUSION

Diluted PVI (0.35-3.5% for 3 minutes) may be beneficial in the prevention of PPI. Evidence supports its use both in the setting of primary implantation as well as salvage of infected hardware. An improved, evidence-based protocol may increase positive outcomes of urologic prosthetic surgery. Pan S, Rodriguez D, Thirumavalavan N, et al. The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions. J Sex Med 2019;16:781-790.

Beta-caryophyllene enhances wound healing through multiple routes

Beta-caryophyllene is an odoriferous bicyclic sesquiterpene found in various herbs and spices. Recently, it was found that beta-caryophyllene is a ligand of the cannabinoid receptor 2 (CB2). Activation of CB2 will decrease pain, a major signal for inflammatory responses. We hypothesized that beta-caryophyllene can affect wound healing by decreasing inflammation. Here we show that cutaneous wounds of mice treated with beta-caryophyllene had enhanced re-epithelialization. The treated tissue showed increased cell proliferation and cells treated with beta-caryophyllene showed enhanced cell migration, suggesting that the higher re-epithelialization is due to enhanced cell proliferation and cell migration. The treated tissues also had up-regulated gene expression for hair follicle bulge stem cells. Olfactory receptors were not involved in the enhanced wound healing. Transient Receptor Potential channel genes were up-regulated in the injured skin exposed to beta-caryophyllene. Interestingly, there were sex differences in the impact of beta- caryophyllene as only the injured skin of female mice had enhanced re-epithelialization after exposure to beta-caryophyllene. Our study suggests that chemical compounds included in essential oils have the capability to improve wound healing, an effect generated by synergetic impacts of multiple pathways.

Antimicrobial emulsions: Formulation of a triggered release reactive oxygen delivery system

The enzyme glucose oxidase mediates the oxidation of glucose to produce reactive oxygen species (ROS), such as hydrogen peroxide. This reaction and its products are key to providing honey with its antimicrobial properties. Currently, honey is an adherent, highly viscous product that produces ROS by means of a water-initiated reaction. These properties reduce clinical usability and present a formulation problem for long term stability. This study aims to engineer a water-in-oil emulsion containing an engineered honey (SurgihoneyRO™) that is easy to administer topically and is controllably activated in-situ. Paraffin oil continuous emulsions formulated using the emulsifier polyglycerol polyricinoleate displayed shear-thinning characteristics. Viscosities between 1.4 and 19.3 Pa·s were achieved at a shear rate representative of post-mixing conditions (4.1 s^-1) by changing the volume of the dispersed phase (30-60%). Notably, this wide viscosity range will be useful in tailoring future formulations for specific application mechanisms. When exposed to water and shear, these emulsion systems were found to undergo catastrophic phase inversion, evidenced by a change in conductivity from 0 μS in the non-aqueous state, to >180 μS in the sheared, inverted state. Encouragingly, sheared formulations containing ≥50% SurgihoneyRO™ generated sufficient levels of ROS to inhibit growth of clinically relevant Gram-positive and Gram-negative bacteria. This study demonstrates an ability to formulate ROS producing emulsions for use as an alternative to current topical antibiotic-based treatments. Promisingly, the ability of this system to release water-sensitive actives in response to shear may be useful for controlled delivery of other therapeutic molecules.

Zebrafish fin-derived fibroblast cell line: A model for in vitro wound healing

The goal of this study was to develop and characterize a cell line from the caudal fin tissue of zebrafish and also its application as an in vitro model to study the effect of H₂ O₂ in wound healing. Fibroblastic cell line was developed using explant culture method from caudal fin tissue of zebrafish and characterized. This cell line was named as DrF cell line. The DrF cells treated with 0-10 µM/ml H₂ O₂ were tested for viability, proliferation and motility by MTT assay, trypan blue assay and chemotaxis assay, respectively. Among the different concentrations of H₂ O₂ , 4 µM was found to be nontoxic to study cell migration in in vitro scratch wound assay. Furthermore, the expression of proliferating cell nuclear antigen (PCNA) and chemokine receptor (CXCR4) genes was carried by qPCR. The cell survival, proliferation and migration were extremely enriched at 4 µM level of H₂ O₂ . We observed accelerated wound closure in DrF cells treated with H₂ O_2. The qPCR results indicated that H₂ O₂ markedly up-regulated mRNA expression of PCNA and CXCR4. The findings from our study suggest that H₂ O₂ at low levels promotes cell survival, proliferation, migration and wound healing in DrF cells.

Hydrogen peroxide (H2O2): a review of its use in surgery

Hydrogen peroxide has been used in medicine for more than 100 years. It is known in surgery as a highly useful irrigation solution by virtue of both its hemostatic and its antimicrobial effects. Due to its possible negative effect on wound healing and its cytotoxic effect in higher concentrations, there are concerns about the safety of its use. The objective of this paper is to review the safety and beneficial effects of hydrogen peroxide.

Macrophages and fibroblasts during inflammation and tissue repair in models of organ regeneration

This review provides a concise summary of the changing phenotypes of macrophages and fibroblastic cells during the local inflammatory response, the onset of tissue repair, and the resolution of inflammation which follow injury to an organ. Both cell populations respond directly to damage and present coordinated sequences of activation states which determine the reparative outcome, ranging from true regeneration of the organ to fibrosis and variable functional deficits. Recent work with mammalian models of organ regeneration, including regeneration of full‐thickness skin, hair follicles, ear punch tissues, and digit tips, is summarized and the roles of local immune cells in these systems are discussed. New investigations of the early phase of amphibian limb and tail regeneration, including the effects of pro‐inflammatory and anti‐inflammatory agents, are then briefly discussed, focusing on the transition from the normally covert inflammatory response to the initiation of the regeneration blastema by migrating fibroblasts and the expression of genes for limb patterning.

Hydrogen Peroxide: A Potential Wound Therapeutic Target?

Hydrogen peroxide (H2O2) is a topical antiseptic used in wound cleaning which kills pathogens through oxidation burst and local oxygen production. H2O2 has been reported to be a reactive biochemical molecule synthesized by various cells that influences biological behavior through multiple mechanisms: alterations of membrane potential, generation of new molecules, and changing intracellular redox balance, which results in activation or inactivation of different signaling transduction pathways. Contrary to the traditional viewpoint that H2O2 probably impairs tissue through its high oxidative property, a proper level of H2O2 is considered an important requirement for normal wound healing. Although the present clinical use of H2O2 is still limited to the elimination of microbial contamination and sometimes hemostasis, better understanding towards the sterilization ability and cell behavior regulatory function of H2O2 within wounds will enhance the potential to exogenously augment and manipulate healing.

Fetal wound healing biomarkers

Fetal skin has the intrinsic capacity for wound healing, which is not correlated with the intrauterine environment. This intrinsic ability requires biochemical signals, which start at the cellular level and lead to secretion of transforming factors and expression of receptors, and specific markers that promote wound healing without scar formation. The mechanisms and molecular pathways of wound healing still need to be elucidated to achieve a complete understanding of this remodeling system. The aim of this paper is to discuss the main biomarkers involved in fetal skin wound healing as well as their respective mechanisms of action.

Pullulan hydrogels improve mesenchymal stem cell delivery into high-oxidative-stress wounds

Cell-based therapies for wound repair are limited by inefficient delivery systems that fail to protect cells from the acute inflammatory environment. Here, a biomimetic hydrogel system is described that is based on the polymer pullulan, a carbohydrate glucan known to exhibit potent antioxidant capabilities. It is shown that pullulan hydrogels are an effective cell delivery system and improve mesenchymal stem cell survival and engraftment in high-oxidative-stress environments. The results suggest that glucan hydrogel systems may prove beneficial for progenitor-cell-based approaches to skin regeneration.

Evaluation of LHP® (1% hydrogen peroxide) cream versus petrolatum and untreated controls in open wounds in healthy horses: a randomized, blinded control study

Background

Treatment and protection of wounds in horses can be challenging; protecting bandages may be difficult to apply on the proximal extremities and the body. Unprotected wounds carry an increased risk of bacterial contamination and subsequent infection which can lead to delayed wound healing. Topical treatment with antimicrobials is one possibility to prevent bacterial colonization or infection, but the frequent use of antimicrobials ultimately leads to development of bacterial resistance which is an increasing concern in both human and veterinary medicine.

Methods

Standardized wounds were created in 10 Standardbred mares. Three wounds were made in each horse. Two wounds were randomly treated with LHP^® or petrolatum and the third wound served as untreated control. All wounds were assessed daily until complete epithelization. Protocol data were recorded on day 2, 6, 11, 16, 21 and 28. Data included clinical scores for inflammation and healing, photoplanimetry for calculating wound areas and swab cytology to assess bacterial colonization and inflammation. Bacterial cultures were obtained on day 2, 6 and 16.

Results

Mean time to complete healing for LHP^® treated wounds was 32 days (95%CI = 26.9-37.7). Mean time to complete healing for petrolatum and untreated control wounds were 41.6 days (95%CI = 36.2-47.0) and 44.0 days (95%CI = 38.6-49.4) respectively. Wound healing occurred significantly faster in LHP^® wounds compared to both petrolatum (p = 0.0004) and untreated controls (p < 0.0001). There was no significant difference in time for healing between petrolatum and untreated controls. Total scores for bacteria and neutrophils were significantly (p < 0.0001) lower for LHP^® treated wounds compared to petrolatum from day 16 and onwards. Staphylococcus aureus and Streptococcus zooepidemicus were only found in cultures from petrolatum treated wounds and untreated controls.

Conclusions

Treatment with LHP^® reduced bacterial colonization and was associated with earlier complete wound healing. LHP^® cream appears to be safe and effective for topical wound treatment or wound protection.

Cell resilience in species life spans: a link to inflammation?

Species differences in life span have been attributed to cellular survival during various stressors, designated here as 'cell resilience'. In primary fibroblast cultures, cell resilience during exposure to free radicals, hypoglycemia, hyperthermia, and various toxins has shown generally consistent correlations with the species characteristic life spans of birds and mammals. However, the mechanistic links of cell resilience in fibroblast cultures to different species life spans are poorly understood. We propose that certain experimental stressors are relevant to somatic damage in vivo during inflammatory responses of innate immunity, particularly, resistance to reactive oxygen species (ROS), low glucose, and hyperthermia. According to this hypothesis, somatic cell resilience determines species differences in longevity during repeated infections and traumatic injuries in the natural environment. Infections and injury expose local fibroblasts and other cells to ROS generated by macrophages and to local temperature elevations. Systemically, acute phase immune reactions cause hypoglycemia and hyperthermia. We propose that cell resilience to somatic stressors incurred in inflammation is important in the evolution of longevity and that longer-lived species are specifically more resistant to immune-related stressors. This hypothesis further specifies Kirkwood's disposable soma theory. We suggest expanding the battery of stressors and markers used for comparative studies to additional cell types and additional parameters relevant to host defense and to their ecological specificities.

Cutaneous scarring: a clinical review

Cutaneous scarring can cause patients symptoms ranging from the psychological to physical pain. Although the process of normal scarring is well described the ultimate cause of pathological scarring remains unknown. Similarly, exactly how early gestation fetuses can heal scarlessly remains unsolved. These questions are crucial in the search for a preventative or curative antiscarring agent. Such a discovery would be of enormous medical and commercial importance, not least because it may have application in other tissues. In the clinical context the assessment of scars is becoming more sophisticated and new physical, medical and surgical therapies are being introduced. This review aims to summarise some of the recent developments in scarring research for non-specialists and specialists alike.

Overexpression of manganese superoxide dismutase in human dermal fibroblasts enhances the contraction of free floating collagen lattice: implications for ageing and hyperplastic scar formation

Cell-matrix interactions are of significant importance for tissue homeostasis of the skin and, if disturbed, may lead to ageing and hyperplastic scar formation. We have studied fibroblasts stably overexpressing manganese superoxide dismutase (MnSOD) with a defined capacity for the removal of superoxide anions and concomitant accumulation of hydrogen peroxide to evaluate the role of enhanced MnSOD activity on the dynamics of cell-matrix interactions in the three-dimensional collagen lattice contraction assay. MnSOD overexpressing fibroblast populated collagen lattices revealed a significantly enhanced contraction compared to collagen lattices populated with vector control cells. The enhanced collagen lattice contraction was in part due to an increase in active TGF-beta1 and the accumulation of H2O2 in MnSOD overexpressing fibroblasts populated collagen lattices. Inhibition of TGF-beta1 signalling by the ALK4,5,7 kinases' inhibitor SB431542 at least partly inhibited the enhanced collagen lattice contraction of MnSOD overexpressing fibroblasts populated lattices. In addition, supplementation of vector control fibroblast populated collagen lattices with recombinant TGF-beta1 concentration dependently enhanced the collagen lattice contraction. In the presence of the antioxidant Ebselen, a mimic of H2O2 and other hydroperoxides/peroxynitrite-detoxifying glutathione peroxidase, collagen lattice contraction and the activation of TGF-beta1 were significantly reduced in collagen lattices populated with MnSOD overexpressing fibroblasts. Collectively, these data suggest that H2O2 or other hydroperoxides or peroxynitrite or a combination thereof may function as important second messengers in collagen lattice contraction and act at least in part via TGF-beta1 activation.

Fetal wound healing using a genetically modified murine model: the contribution of P-selectin

PURPOSE

During early gestation, fetal wounds heal with paucity of inflammation and absent scar formation. P-selectin is an adhesion molecule that is important for leukocyte recruitment to injury sites. We used a murine fetal wound healing model to study the specific contribution of P-selectin to scarless wound repair.

METHODS

Linear excisional wounds were created on the dorsa of E15.5 and E17.5 gestation fetuses in wild-type and P-selectin (-/-) mice (term = 19 days). Wounds were harvested at various time-points after wounding and analyzed using histology and immunohistochemistry.

RESULTS

The E15.5 wounds in both wild-type and P-selectin (-/-) fetuses healed scarlessly and with minimal inflammation, whereas E17.5 wounds healed with fibrosis and inflammation. However, the scars of the P-selectin (-/-) wounds appeared slightly different than wild-type. There were significantly more inflammatory cells in E17.5 wild-type wounds 6 hours after injury (P < .001), but the difference was no longer significant by 24 hours. Finally, reepithelialization was slower in the E15.5 knockout wounds compared to their wild-type counterparts.

CONCLUSIONS

Absence of P-selectin delays inflammatory cell recruitment and reepithelialization of fetal wounds; however, scar formation still occurs in late gestation wounds. The contribution of specific molecules to fetal wound healing can be elucidated using murine knockout or transgenic models.

Hydrogen peroxide and wound healing: a theoretical and practical review for hair transplant surgeons

BACKGROUND

In most hair restoration practices, hydrogen peroxide has been routinely used to remove blood during and after hair transplant surgery. In other specialties, hydrogen peroxide is also used in these ways: wound cleaning, prevention of infection, hemostasis, and removal of debris. Despite its widespread use, there are still concerns and controversy about the potential toxic effect of hydrogen peroxide.

OBJECTIVE

The objective was to review all available literature including in vivo and in vitro effects of hydrogen peroxide, as well as general wound healing research.

MATERIAL AND METHODS

Literature up to and including the past three decades was investigated.

RESULTS

Two pilot studies were found, and there are not enough data examining the real impact of using hydrogen peroxide in hair transplant surgery. In other specialties, H(2)O(2) appears to have positive effects, such as stimulation of vascular endothelial growth factor, induction of fibroblast proliferation, and collagen, or negative effects, such as cytotoxicity, inhibition of keratinocyte migration, disruption of scarless fetal wound repair, and apoptosis.

CONCLUSIONS

There are not enough data in hair restoration surgery about the use of hydrogen peroxide, and it is unknown and unclear what the optimum dilution should be. Positive and negative effects were found in other specialties. Further studies are recommended. The authors have indicated no significant interest with commercial supporters.

Surgical and Traumatic Wound Infections, Cellulitis, and Myositis in Horses

Surgical site infections (SSIs) and traumatic wound management remain challenging clinical scenarios. The prevention of SSIs involves meticulous surgical technique and aftercare. Traumatic wounds require thorough evaluation to assess the involvement of synovial structures and radiographs to check for fractures. Chronic wounds can require a biopsy and histologic evaluation to obtain a diagnosis, because many underlying pathologic processes grossly appear similar but different treatment regimens are required. Early recognition and diagnosis of cellulitis and myositis enable the rapid aggressive intervention necessary for a positive outcome. Any delay in diagnosis and treatment increases the complication and mortality rates and makes these conditions difficult to treat successfully.