Mechanisms of delayed wound healing by commonly used antiseptics

Oxidative stress responses in biofilms

Oxidizing agents are low-molecular-weight molecules that oxidize other substances by accepting electrons from them. They include reactive oxygen species (ROS), such as superoxide anions (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (HO-), and reactive chlorine species (RCS) including sodium hypochlorite (NaOCl) and its active ingredient hypochlorous acid (HOCl), and chloramines. Bacteria encounter oxidizing agents in many different environments and from diverse sources. Among them, they can be produced endogenously by aerobic respiration or exogenously by the use of disinfectants and cleaning agents, as well as by the mammalian immune system. Furthermore, human activities like industrial effluent pollution, agricultural runoff, and environmental activities like volcanic eruptions and photosynthesis are also sources of oxidants. Despite their antimicrobial effects, bacteria have developed many mechanisms to resist the damage caused by these toxic molecules. Previous research has demonstrated that growing as a biofilm particularly enhances bacterial survival against oxidizing agents. This review aims to summarize the current knowledge on the resistance mechanisms employed by bacterial biofilms against ROS and RCS, focussing on the most important mechanisms, including the formation of biofilms in response to oxidative stressors, the biofilm matrix as a protective barrier, the importance of detoxifying enzymes, and increased protection within multi-species biofilm communities. Understanding the complexity of bacterial responses against oxidative stress will provide valuable insights for potential therapeutic interventions and biofilm control strategies in diverse bacterial species.

Functionalization of Bacterial Cellulose with the Antimicrobial Peptide KR-12 via Chimerical Cellulose-Binding Peptides

Bacterial-derived cellulose (BC) has been studied as a promising material for biomedical applications, including wound care, due to its biocompatibility, water-holding capacity, liquid/gas permeability, and handleability properties. Although BC has been studied as a dressing material for cutaneous wounds, to date, BC inherently lacks antibacterial properties. The current research utilizes bifunctional chimeric peptides containing carbohydrate binding peptides (CBP; either a short version or a long version) and an antimicrobial peptide (AMP), KR-12. The secondary structure of the chimeric peptides was evaluated and confirmed that the α-helix structure of KR-12 was retained for both chimeric peptides evaluated (Long-CBP-KR12 and Short-CBP-KR12). Chimeric peptides and their individual components were assessed for cytotoxicity, where only higher concentrations of Short-CBP and longer timepoints of Short-CBP-KR12 exposure exhibited negative effects on metabolic activity, which was attributed to solubility issues. All KR-12-containing peptides exhibited antibacterial activity in solution against Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). The lipopolysaccharide (LPS) binding capability of the peptides was evaluated and the Short-CBP-KR12 peptide exhibited enhanced LPS-binding capabilities compared to KR-12 alone. Both chimeric peptides were able to bind to BC and were observed to be retained on the surface over a 7-day period. All functionalized materials exhibited no adverse effects on the metabolic activity of both normal human dermal fibroblasts (NHDFs) and human epidermal keratinocyte (HaCaT) epithelial cells. Additionally, the BC tethered chimeric peptides exhibited antibacterial activity against E. coli. Overall, this research outlines the design and evaluation of chimeric CBP-KR12 peptides for developing antimicrobial BC membranes with potential applications in wound care.

Autologous adipose-derived stromal vascular fraction and platelet concentrates for the treatment of complex perianal fistulas

BACKGROUND

Complex perianal fistulas are a major challenge for modern surgery since 10-35% of patients have functional problems after treatment. Sphincter-saving techniques have a wide range of efficacy (10-80%). We hypothesised that autologous adipose-derived stromal vascular fraction in combination with platelet rich plasma is a new therapeutic strategy with enhanced cure and function preservation rates.

METHODS

Adult patients with complex cryptoglandular perianal fistulas were treated with injection of autologous adipose-derived stromal vascular fraction in combination with platelet rich plasma around and inside the fistulous tract between May 2018 and April 2019 at the General and Emergency Surgery Operative Unit of the University Hospital "P. Giaccone" of Palermo. Fistulas were confirmed by magnetic resonance imaging. Patients completed the Short Form-36 score on quality of life and the Wexner and Vaizey scores on faecal incontinence, and they were functionally studied using a three-dimensional anorectal manometry. The clinical and functional follow-up was performed at 1 year and 2 years after surgery.

RESULTS

Nine patients (4 males, 5 females; median age 42 years [19-63 years]) with high trans-sphincteric or horseshoe fistulas were treated. The average number of previous surgeries per patient was 4.8. At 1 year follow-up, 77.7% of patients were cured, while at 2 years there was 1case of relapse. The variation in Short Form-36 score in cured patients was not significant (p = 0.0936). No statistically significant differences were found in continence scores.

CONCLUSIONS

The proposed treatment is a treatment option that preserves sphincter integrity and function, potentially avoiding postoperative incontinence and the need of repeated treatments.

Histopathological Evaluation of the Healing Process of Standardized Skin Burns in Rabbits: Assessment of a Natural Product with Honey and Essential Oils

Skin burns are one of the most difficult medical problems. Recently, studies have been directed towards development of natural products in order to identify effective and safe remedies. In the present study, we evaluated the efficacy of a natural composite (formulated from honey and essential oils) compared with MEBO® (0.25% β-sitosterol) and DERMAZIN® creams (1% silver-sulfadiazine) in the treatment of thermally induced skin burns. For this purpose, four burn-wounds were created on the back of male New Zealand rabbits (n = 10) using a thermal stamp under the effect of general anesthesia. Each wound represents one of the following groups: non-treated, natural composite-cream, MEBO®-cream, and silver-sulfadiazine treated groups, respectively. Treatments were applied once a day topically until one of these wounds appeared to be healed grossly. The non-treated group received no treatment. Grossly, skin burns have been healed after 28 days of the treatment in all groups except of the non-treated group. The healing efficacy of the natural composite, MEBO® and silver-sulfadiazine creams was quite similar macroscopically. However, microscopically, the epidermal layer of the composite-cream treated group was more mature than those of both MEBO® and silver-sulfadiazine creams treated groups. In conclusion, the tested composite may be a promising effective and inexpensive treatment of skin burns.

Extracts of Rheum palmatum and Aloe vera Show Beneficial Properties for the Synergistic Improvement of Oral Wound Healing

Various local and systemic factors compromise oral wound healing and may lead to wound dehiscence, inflammation, or ulcers. Currently, there is a lack of topical therapeutical options. Thus, this study aimed to investigate the effect of Aloe vera (AV) and Rheum palmatum root (RPR) on oral wound healing capacity in vitro. The effect of AV and RPR on human primary fibroblast viability and migration was studied by measuring metabolic activity and gap closure in a scratch assay. Furthermore, cell cycle distribution and cytoskeletal features were analyzed. Antimicrobial activity against the oral pathogen Porphyromonas gingivalis was evaluated by broth microdilution assay. AV and RPR increased fibroblast migration after single agent treatment. Synergistic effects of the plant extract combination were observed regarding cellular migration which were confirmed by calculation of the phenomenological combination index (pCI), whereas the cell cycle distribution was not influenced. Furthermore, the combination of AV and RPR showed synergistic antibacterial effects as determined by the fractional inhibitory concentration index. This study demonstrated that the combination of AV and RPR can promote the migration of human primary fibroblasts in vitro and exert antimicrobial efficacy against P. gingivalis, suggesting these compounds for the topical treatment of wound healing disorders.

Robbing Peter to Pay Paul: Chlorhexidine gluconate demonstrates short-term efficacy and long-term cytotoxicity

Wound cleansing agents are routine in wound care and preoperative preparation. Antiseptic activity intends to prevent contaminating microbes from establishing an infection while also raising concerns of cytotoxicity and delayed wound healing. We evaluated the cytotoxicity of five clinically used wound cleaning agents (saline, povidone iodine, Dove® and Dial® soaps, and chlorhexidine gluconate [CHG]) using both an ex vivo and in vivo human skin xenograft mouse model, in contrast to classical in vitro models that lack the structural and compositional heterogeneity of human skin. We further established an ex vivo wound contamination model inoculated with ~100 cells of Pseudomonas aeruginosa or Staphylococcus aureus to evaluate antimicrobial efficacy. Scanning electron microscopy and confocal microscopy were used to evaluate phenotypic and spatial characteristics of bacterial cells in wound tissue. CHG significantly reduced metabolic activity of the skin explants, while all treatments except saline affected local cellular viability. CHG cytotoxicity persisted and progressed over 14 days, impairing wound healing in vivo. Within the contamination model, CHG treatment resulted in a significant reduction of P. aeruginosa wound surface counts at 24 h post-treatment. However, this effect was transient and serial application of CHG had no effect on both P. aeruginosa or S. aureus microbial growth. Microscopy revealed that viable cells of P. aeruginosa reside deep within wound tissue post-CHG application, likely serving as a reservoir to re-populate the tissue to a high bioburden. We reveal concerning cytotoxicity and limited antimicrobial activity of CHG in human skin using clinically relevant models, with the ability to resolve spatial localization and temporal dynamics of tissue viability and microbial growth.

Meticillin-susceptible Staphylococcus aureus pyomyositis and cellulitis in right thigh of a 15-year-old boy: a case study

Pyomyositis is a purulent infection of striated muscle and postoperative management remains the mainstay. If delayed primary wound closure is not managed in a timely manner, it often results in recurrent infection and sinus tract creation. Cavity wounds with sinus formation are known to complicate treatment, are problematic to manage and persist for long periods of time. The aim of this case report is to present the challenges in the assessment and management of a sinus tract with deep cavity wound, between the vastus lateralis and biceps femoris muscles, originating from liquefaction of a haematoma. Our review of the literature revealed limited research evidence in the management of deep cavity wounds. This is a rare case where the sinus tract route which leads to the rim-shaped cavity is embedded deep between the muscles, posing a high risk of recurrent infection from the premature closure of the wound tract. Successful management was attributed to: the accuracy in the initial wound assessment; appropriate dressing plans; the rationale for each action; and an outcome goal as each treatment progressed. Daily dressing change and reassessment of the wound was required to ensure progress and to address any complications in a timely manner. Finally, concerns of the patient and their family and regular discussions on the treatment plans are important to encourage adherence with management goals.

Cytotoxicity and Wound Closure Evaluation in Skin Cell Lines after Treatment with Common Antiseptics for Clinical Use

In recent years, new therapies, such as skin cell lines injections, have emerged to promote re-epithelialization of damaged areas such as chronic ulcers or to treat patients with severe burns. Antiseptics are commonly used during wound clinical management to avoid serious infections, but they may delay the healing process due to their apparent cytotoxicity to skin cells. The cytotoxicity of ethanol, chlorhexidine digluconate, sodium hypochlorite, povidone iodine and polyhexanide was evaluated in this in vitro study on human fibroblasts and keratinocytes. Treatments were applied to each cell type culture every 48 h for 14 days. To determine the cytotoxic of antiseptics, cell viability (Live/Dead^®) and cell proliferation (AlamarBlue™) assays were performed on cell monolayers. Cell migration capacity was evaluated with a wound closure assay. Results showed how chlorhexidine digluconate and ethanol significantly reduced the viability of keratinocytes and inhibited cell migration. Povidone iodine followed by chlorhexidine digluconate significantly reduced fibroblast cell viability. Povidone iodine also inhibited cell migration. Sodium hypochlorite was the least detrimental to both cell types. If epithelial integrity is affected, the wound healing process may be altered, so the information gathered in this study may be useful in selecting the least aggressive antiseptic after treatment with new emerging therapies.

Effect of dental antiseptic agents on the viability of human periodontal ligament cells

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Cell viability is key for tissue regeneration.

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Dental antiseptics were cytotoxic in periodontal ligament cells.

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Real-time impedimetry proved to be a non-invasive method to monitor cell viability.

Objectives

We aimed to study whether or not various dental antiseptic agents affect the viability and proliferation of human periodontal ligament cells (PDLCs).

Materials and methods

Human PDLCs were isolated from a total of 10 surgically extracted impacted third molars and were.

cultured in-vitro. The cells were exposed to commonly used dental antiseptics, including chlorhexidine, cetylpyridinium chloride, triclosan, povidone-iodine and sodium bicarbonate for ultra-short-term (10, 20, 30 sec), short-term (10, 20, 30 min) and long-term (24, 48 h) at various concentrations. Cell morphology was observed with light microscopy. Cell viability was studied with impedimetric real-time xCELLigence and resazurin-based alamarBlue® assays. We used one-way ANOVA with Tukey’s and Bonferroni test (p < 0.05) for statistical analysis.

Results

Both alamarBlue® and xCELLigence analysis results were in agreement that ultra-short-term contact with cetylpyridinium chloride ≥ 0.01 mg/ml, chlorhexidine ≥ 1 mg/ml, triclosan ≥ 1 mg/ml and povidone-iodine ≥ 1 mg/ml as well as long-term exposure to cetylpyridinium chloride ≥ 0.001 mg/ml, chlorhexidine ≥ 0.01 mg/ml, triclosan ≥ 1 mg/ml, povidone-iodine ≥ 1 mg/ml and sodium bicarbonate ≥ 10 mg/ml was able to reduce the viability of human PDLCs significantly. According to the half-maximal inhibitory concentration (IC50) the rank of cytotoxicity was cetylpyridinium chloride > chlorhexidine > triclosan > povidone-iodine > sodium bicarbonate.

Conclusions

Our findings suggest that the tested antiseptic agents were cytotoxic to human PDLCs at lower than practically applied concentrations in dental interventions.

Effect of Chlorhexidine Digluconate in Early Wound Healing of Human Gingival Tissues. A Histological, Immunohistochemical and Biomolecular Analysis

Chlorhexidine digluconate (CHX) is considered the gold standard for oral cavity antiseptic treatment. Nevertheless, several in vitro studies have reported detrimental effects in oral tissue repair. The aim of the present study was to evaluate the in vivo effect of post-surgical CHX mouth rinse on gingival tissue (G) 24 h after injury. G biopsies were obtained in three patients 24 h after surgery with the indication of post-surgical 0.12% CHX use and were compared with those obtained from the same patients without any antiseptic use. Changes in collagen production, cell proliferation, and apoptosis were examined by histological and Ki-67/P53 immunohistochemical analysis. Fibrotic markers (COL1A1, αSMA), proapoptotic protein (BAX) expression, and wound healing-related gene modulation (RAC1, SERPINE1, TIMP1) were analyzed by quantitative real-time PCR analysis. CHX was able to reduce cellular proliferation and increase collagen deposition, proapoptotic molecule and fibrotic marker expression, and myofibroblast differentiation, reduce expression of RAC1 and trigger expression of SERPINE1 and TIMP1, showing “scar wound healing response” pattern. This study assessed for the first time the in vivo effects of CHX on gingival tissue. The demonstration of a CHX-induced fibrotic transformation, leading to scar repair, supports the need for new post-surgical clinical protocols based on a strategic and personalized use of CHX.

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.

Estrategias de protección antimicrobiana en el cuidado de heridas: evidencia para el uso de apósitos recubiertos con DACC

BACKGROUND

Antimicrobial resistance (AMR) is one of the most serious health threats globally. The development of new antimicrobials is not keeping pace with the evolution of resistant microorganisms, and novel ways of tackling this problem are required. One of such initiatives has been the development of antimicrobial stewardship programmes (AMS). The use of wound dressings that employ a physical sequestration and retention approach to reduce bacterial burden offers a novel approach to support AMS. Bacterial-binding by dressings and their physical removal can minimise their damage and prevent the release of harmful endotoxins.

OBJECTIVE

To highlight AMS to promote the correct use of antimicrobials and to investigate how dialkylcarbamyl chloride (DACC)-coated dressings can support AMS.

METHOD

MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify articles relating to AMS, and the use of wound dressings in the prevention and treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent wound infection in a way that does not kill or damage the microorganisms were reviewed.

RESULTS

The evidence demonstrated that using bacterial-binding wound dressings that act in a physical manner (eg, DACC-coated dressings) to preventing infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS.

CONCLUSION

Some wound dressings work via a mechanism that promotes the binding and physical sequestration and removal of intact microorganisms from the wound bed (eg, a wound dressing that uses DACC technology to prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.

Antisense yycG modulates the susceptibility of Staphylococcus aureus to hydrogen peroxide via the sarA

Background

The infectious pathogen Staphylococcus aureus (S. aureus) is primarily associated with osteomyelitis. Hydrogen peroxide drainage is an effective antimicrobial treatment that has been adopted to combat S. aureus infections. Previous investigations have indicated that the antisense RNA (asRNA) strategy negatively modulates S. aureus YycFG TCS, and it significantly disrupts biofilm formation. However, the effects of the antisense yycG RNA (ASyycG) strategy on the susceptibility of biofilm-producing S. aureus to hydrogen peroxide and the mechanisms underlying this effect have not been elucidated to date.

Results

Overexpression of ASyycG inhibited the transcription of biofilm formation-related genes, including sarA and icaA. Additionally, the CFU counts and the live bacterial ratios of ASyycG biofilm-producing S. aureus treated with H₂O₂ were notably reduced across the groups. Notably, the predicted promoter regions of the sarA and icaA genes were directly regulated by YycF.

Conclusions

ASyycG was observed to sensitize biofilm-producing S. aureus to H₂O₂ intervention synergistically via the sarA and thus may represent a supplementary strategy for managing osteomyelitis. However, future in-depth studies should attempt to replicate our findings in animal models, such as the rat osteomyelitis model.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02218-x.

Nanoceutical Adjuvants as Wound Healing Material: Precepts and Prospects

Dermal wound healing describes the progressive repair and recalcitrant mechanism of 12 damaged skin, and eventually, reformatting and reshaping the skin. Many probiotics, nutritional supplements, metal nanoparticles, composites, skin constructs, polymers, and so forth have been associated with the improved healing process of wounds. The exact mechanism of material-cellular interaction is a point of immense importance, particularly in pathological conditions such as diabetes. Bioengineered alternative agents will likely continue to dominate the outpatient and perioperative management of chronic, recalcitrant wounds as new products continue to cut costs and improve the wound healing process. This review article provides an update on the various remedies with confirmed wound healing activities of metal-based nanoceutical adjuvanted agents and also other nano-based counterparts from previous experiments conducted by various researchers.

Antimicrobial stewardship strategies in wound care: evidence to support the use of dialkylcarbamoyl chloride (DACC)- coated wound dressings

BACKGROUND

Traditionally, infections are treated with antimicrobials (for example, antibiotics, antiseptics, etc), but antimicrobial resistance (AMR) has become one of the most serious health threats of the 21st century (before the emergence of COVID-19). Wounds can be a source of infection by allowing unconstrained entry of microorganisms into the body, including antimicrobial-resistant bacteria. The development of new antimicrobials (particularly antibiotics) is not keeping pace with the evolution of resistant microorganisms and novel ways of addressing this problem are urgently required. One such initiative has been the development of antimicrobial stewardship (AMS) programmes, which educate healthcare workers, and control the prescribing and targeting of antimicrobials to reduce the likelihood of AMR. Of great importance has been the European Wound Management Association (EWMA) in supporting AMS by providing practical recommendations for optimising antimicrobial therapy for the treatment of wound infection. The use of wound dressings that use a physical sequestration and retention approach rather than antimicrobial agents to reduce bacterial burden offers a novel approach that supports AMS. Bacterial-binding by dressings and their physical removal, rather than active killing, minimises their damage and hence prevents the release of damaging endotoxins.

AIM

Our objective is to highlight AMS for the promotion of the judicious use of antimicrobials and to investigate how dialkylcarbamoyl chloride (DACC)-coated dressings can support AMS goals.

METHOD

MEDLINE, Cochrane Database of Systematic Reviews, and Google Scholar were searched to identify published articles describing data relating to AMS, and the use of a variety of wound dressings in the prevention and/or treatment of wound infections. The evidence supporting alternative wound dressings that can reduce bioburden and prevent and/or treat wound infection in a manner that does not kill or damage the microorganisms (for example, by actively binding and removing intact microorganisms from wounds) were then narratively reviewed.

RESULTS

The evidence reviewed here demonstrates that using bacterial-binding wound dressings that act in a physical manner (for example, DACC-coated dressings) as an alternative approach to preventing and/or treating infection in both acute and hard-to-heal wounds does not exacerbate AMR and supports AMS.

CONCLUSION

Some wound dressings work via a mechanism that promotes the binding and physical uptake, sequestration and removal of intact microorganisms from the wound bed (for example, a wound dressing that uses DACC technology to successfully prevent/reduce infection). They provide a valuable tool that aligns with the requirements of AMS (for example, reducing the use of antimicrobials in wound treatment regimens) by effectively reducing wound bioburden without inducing/selecting for resistant bacteria.

Effects of Buprenorphine, Chlorhexidine, and Low-level Laser Therapy on Wound Healing in Mice

Systemic buprenorphine and topical antiseptics such as chlorhexidine are frequently used in research animals to aid in pain control and to reduce infection, respectively. These therapeutics are controversial, especially when used in wound healing studies, due to conflicting data suggesting that they delay wound healing. Low-level laser therapy (LLLT) has been used to aid in wound healing without exerting the systemic effects of therapies such as buprenorphine. We conducted 2 studies to investigate the effects of these common treatment modalities on the rate of wound healing in mice. The first study used models of punch biopsy and dermal abrasion to assess whether buprenorphine HCl or 0.12% chlorhexidine delayed wound healing. The second study investigated the effects of sustained-released buprenorphine, 0.05% chlorhexidine, and LLLT on excisional wound healing. The rate of wound healing was assessed by obtaining photographs on days 0, 2, 4, 7, and 9 for the punch biopsy model in study 1, days 0, 1, 2, 4, 6, 8, 11, and 13 for the dermal abrasion model in study 1, and days 0, 3, 6, and 10 for the mice in study 2. Image J software was used to analyze the photographed wounds to determine the wound area. When comparing the wound area on the above days to the original wound area, no significant differences in healing were observed for any of the treatment groups at any time period for either study. Given the results of these studies, we believe that systemic buprenorphine, topical chlorhexidine, and LLLT can be used without impairing or delaying wound healing in mice.

Episiotomy wound healing by Commiphora myrrha (Nees) Engl. and Boswellia carteri Birdw. in primiparous women: A randomized controlled trial

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Persian medicine manuscripts refer to plants such as Commiphora myrrha (Nees) Engl. (myrrh) and Boswellia carteri Birdw. (frankincense), which could be used to improve wound healing process. Since that time, local midwives in Iran continue to provide these herbs to precipitate episiotomy wound healing.

AIM OF THE STUDY

To investigate the efficacy and safety of myrrh- and frankincense-based sitz-baths on episiotomy wound healing in primiparous women.

MATERIALS AND METHODS

This randomized controlled trial was conducted on 90 primiparous women with singleton pregnancies after normal vaginal delivery at Hafez hospital affiliated to Shiraz University of Medical Sciences from July to October 2019. Study participants were randomly allocated in three groups (2 intervention groups and 1 control group). Women in intervention groups were assigned to receive either 10-min sitz-bath of myrrh extract or frankincense extract twice a day for 1 week. While the women in control group received the betadine sitz-bath for the same period of time. The main outcome was the episiotomy wound healing, which was measured using the REEDA scale before intervention, on 2nd and 7th postpartum days.

RESULTS

An improvement in the episiotomy wound healing was significantly greater in patients receiving myrrh than those receiving the frankincense or betadine on 2nd (p = 0.003 and p < 0.001) and 7th (p = 0.043 and p = 0.015) postpartum days. However, the total REEDA score was not statistically different between the frankincense and betadine groups on 2nd and 7th postpartum days (p > 0.05).

CONCLUSION

The present results suggest that myrrh was more efficient than frankincense and betadine in healing of the episiotomy wound and could be recommended as a safe natural therapy.

Investigating the effect of antiseptic solution on the release of interleukin-6 and transforming growth factor beta 1 from human gingival fibroblasts using wound healing assays

This in vitro study evaluated the effect of different antiseptics and different concentrations thereof in a model of wound healing using human gingival fibroblasts. The fibroblasts were rinsed with four different antiseptic solutions: sodium hypochlorite (HYP), hydrogen peroxide (H₂O₂), chlorhexidine digluconate (CHX), and benzalkonium chloride (BC). The effect on the release of interleukin-6 (IL-6) and transforming growth factor beta 1 (TGF-β1) was investigated using enzyme-linked immunosorbent assays (ELISAs). In addition, the effects of the antiseptics on wound healing at 1, 12, 24, and 48 h were assessed through a wound healing assay. The viability of the fibroblasts rinsed with antiseptics was investigated with respect to the concentrations inhibiting cell growth by 50% (IC₅₀), 25% (IC₂₅), and ≤2% (IC₂). A statistically significant increased release of IL-6 was obtained with BC IC₂₅ and IC₂ after 12, 24, and 48 h (P < 0.01). For TGF-β1, no significant release was found for CHX IC₂ after 24 and 48 h or for IC₅₀ and IC₂₅ after 12 h. There was no significant effect on wound healing capacity for CHX or for BC IC₂₅ and IC₂. This study demonstrated that antiseptic rinses of human gingival fibroblasts alter the release of IL-6 and TGF-β1 and impact wound healing capacity, with both BC and CHX conferring neutral effects.

Optimizing Breast Pocket Irrigation: The Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL) Era

BACKGROUND

Specific antimicrobial breast pocket irrigations have been proven over the past 20 years to reduce the incidence of capsular contracture by a factor of 10, and the emergence of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) and its link to bacteria/technique has created renewed interest in different antimicrobial breast pocket preparation agents. Our previous studies have identified that both Betadine-containing and non-Betadine-containing antimicrobial irrigations provide excellent broad-spectrum bacterial coverage. The current science of BIA-ALCL has implicated the Gram-negative microbiome as a key in pathogenesis.

OBJECTIVES

The aim of this study was to revisit the antimicrobial effectiveness of clinically utilized Betadine and non-Betadine solutions, along with other antimicrobial agents that have not yet been tested, against multiple organisms, including additional common Gram-negative bacteria associated with chronic breast implant infections/inflammation.

METHODS

Current and new antimicrobial breast irrigations were tested via standard techniques for bactericidal activity against multiple Gram-positive and Gram-negative strains. Test results are detailed and clinical recommendations for current antimicrobial irrigations are provided.

RESULTS

Betadine-containing irrigations were found to be superior according to the testing performed.

CONCLUSIONS

There are quite few misconceptions with regard to antimicrobial breast pocket irrigation. These are discussed and final evidence-based recommendations for practice are given.

Multifunctional Antimicrobial Nanofiber Dressings Containing ε-Polylysine for the Eradication of Bacterial Bioburden and Promotion of Wound Healing in Critically Colonized Wounds

Bacterial colonization of acute and chronic wounds is often associated with delayed wound healing and prolonged hospitalization. The rise of multi-drug resistant bacteria and the poor biocompatibility of topical antimicrobials warrant safe and effective antimicrobials. Antimicrobial agents that target microbial membranes without interfering with the mammalian cell proliferation and migration hold great promise in the treatment of traumatic wounds. This article reports the utility of superhydrophilic electrospun gelatin nanofiber dressings (NFDs) containing a broad-spectrum antimicrobial polymer, ε-polylysine (εPL), crosslinked by polydopamine (pDA) for treating second-degree burns. In a porcine model of partial thickness burns, NFDs promoted wound closure and reduced hypertrophic scarring compared to untreated burns. Analysis of NFDs in contact with the burns indicated that the dressings trap early colonizers and elicit bactericidal activity, thus creating a sterile wound bed for fibroblasts migration and re-epithelialization. In support of these observations, in porcine models of Pseudomonas aeruginosa and Staphylococcus aureus colonized partial thickness burns, NFDs decreased bacterial bioburden and promoted wound closure and re-epithelialization. NFDs displayed superior clinical outcome than standard-of-care silver dressings. The excellent biocompatibility and antimicrobial efficacy of the newly developed dressings in pre-clinical models demonstrate its potential for clinical use to manage infected wounds without compromising tissue regeneration.

Measures to reduce end-of-case wound contamination: the impact of intra-wound vancomycin powder and betadine irrigation on surgical site infections in posterior spinal fusion

STUDY DESIGN

Retrospective descriptive, single-center study.

OBJECTIVES

To determine the effect of standardized intrawound vancomycin powder and betadine irrigation on surgical site infection (SSI) rates after posterior spinal fusion (PSF) in idiopathic scoliosis. Since 2005, our pediatric spine center has implemented a series of changes to lower the risk of SSI. The most recent interventions-intrawound vancomycin powder and betadine irrigation-are applied just before closure, aiming to reduce the culture-positive bacterial contamination known to occur in many cases. We sought to determine the impact of these end-of-case measures on our center's SSI rate.

METHODS

We retrospectively reviewed patients who underwent PSF for idiopathic scoliosis at our institution from January 1, 2010, to June 30, 2018, identifying all cases that returned to the operating room for surgical debridement within 90 days of PSF. Cases were surgeon-audited to ensure inclusion of all infections that met Centers for Disease Control and Prevention (CDC) criteria for acute SSI. Vertical expandable prosthetic titanium ribs, growing rods, staged procedures, and nonidiopathic cases were excluded. Annual rates of SSIs were correlated with the initiation of each SSI prevention measure.

RESULTS

Among 740 cases of PSF for idiopathic scoliosis from 2010 to 2018, the overall acute SSI rate by CDC criteria was 0.68%. The idiopathic SSI rate dropped significantly, from 1.70 to 0.20%, after the standardized introduction of intrawound vancomycin powder and betadine irrigation before closure (p < 0.04). The implementation of these end-of-case measures in 2012-2013 was soon followed by an institution best 3.5-year SSI-free period for idiopathic cases.

CONCLUSIONS

Since intrawound vancomycin powder and betadine irrigation were added to our SSI prevention bundle, we have seen a significantly lower SSI rate after PSFs for idiopathic scoliosis. These findings suggest that anti-SSI interventions to reduce wound contamination at the end of the case may have a particularly positive impact on SSI reduction.

LEVEL OF EVIDENCE

Level III, therapeutic.

Comparison of the effect of postoperative care agents on human gingival fibroblasts: a preliminary study

Purpose:

The aim of this study is to compare effects of postoperative care agents; chlorhexidine, octenidine dihydrochloride and hyaluronic acid on human gingival fibroblasts’ viability, proliferation, apoptosis and migration.

Materials and methods:

After cell culturing; chlorhexidine, octenidine dihydrochloride and hyaluronic acid solutions were applied on cells and nothing was applied for control group. The cells were monitored to investigate cytotoxicity; the percentage of apoptotic, living and dead cells at the time of 24, 48, and 72 hours (h). A scratch wound assay was performed to detect cell migration and cells were monitored at baseline, at 24 and 48h.

Results:

At 24h, chlorhexidine showed statistically lower percentage of total apoptotic cells’ than octenidine dihydrochloride (p=0.049), hyaluronic acid (p=0.049) and control (p=0.049). At 48h, hyaluronic acid showed statistically lower percentage than chlorhexidine (p=0.049), and control (p=0.049). All agents were found to have statistically and significantly more cytotoxic than control. However, there was no difference between experimental groups for proliferation rate. Octenidine dihydrochloride showed statistically negative effects on cell migration than chlorhexidine and hyaluronic acid at 24h. Chlorhexidine and hyaluronic acid maintained migration ability of cells than octenidine dihydrochloride at 48h.

Conclusion:

All agents have similar effects on cell behavior such as viability, apoptosis and cell proliferation. However, octenidine dihydrochloride showed statistically negative effects on migration ability than chlorhexidine and hyaluronic acid.

Effect of Ascophyllan from Brown Algae Padina tetrastromatica on Cell Migration and Extracellular Matrix Stabilisation in Burn Wounds

Background:

Burn injuries are the most common injuries and a major health problem affecting communities worldwide. Many alternative therapies are used as treatment for burns. The healing efficacy of sulphated polysaccharide ascophyllan was evaluated and studied its mechanism of action on experimental burn wounds in rats.

Methods:

Ascophyllan fractions were extracted from marine brown algae Padina tetrastromatica (Dictyotaceae) and evaluated its burn wound healing potential. Full thickness burn wounds induced in male albino rats were used for in vivo study and evaluated wound healing parameters.

Results:

The results showed that Ascophyllan Fraction 3 (AF3) had no cytotoxic effect and it increases cell migration and production of VEGF in fibroblasts. AF3 significantly reduced in vitro secretion of cytokines in blood mononuclear cells treated with Lipopolysaccharide (LPS). In vivo study showed that AF3 (5%) has significant wound healing activity in albino rats and this dose was used for studying the healing mechanism. The reference control used for the study was povidone-iodine ointment. Wound area contraction and reepithelialisation was faster in AF3 (5%) administered group. When applied topically, AF3 (5%) increased hydroxyproline and hexosamine content at the wound site. Uronic acid, DNA and proteins levels were also increased. Compared to the control groups, AF3 (5%) treatment showed an increase in neovascularization and fibroblast proliferation as evidenced by histopathology of granulation tissue.

Conclusion:

Sulphated polysaccharide ascophyllan is beneficial for the wound environment as it enhances the healing process and suggested the safe usage of this algal polysaccharide as an alternative for replacing current synthetic wound healing agents in medicine.

Effect of topical ozonetherapy on gingival wound healing in pigs: histological and immuno-histochemical analysis

OBJECTIVES

In this study, the effects of ozonetherapy on secondary wound healing were evaluated histologically and immuno-histochemically.

MATERIAL AND METHODS

Material and Methods: 8 healthy pigs were used in this study. Six wounds with 10 mm in diameter were created through the punch technique on the palatinal gingiva of each pig. Ozone gas was applied on only 3 wounds (test group) and the remaining 3 were left to natural healing (control group). Biopsy samples were taken from one of the wounds in each group on the third day, from another wound of each group on the seventh day, and from another one on the tenth day. Routine histological analysis and immuno-histochemical staining were performed to investigate transforming growth factor-beta (TGF-β) and (VEGF) expressions.

RESULTS

Results: No statistical difference was found between the test and control groups in terms of collagen fibers, epithelial formation and inflammation scores. A VEGF expression found in the test group was statistically higher than control group samples taken on the 3rd and 7th day. There was no statistical difference between the test and control groups in terms of TGF-β expression on any of the sampling days.

CONCLUSIONS

Conclusion: The topical application of ozone gas could be effective in the early stages of wound healing by increasing the amount of VEGF expression. Clinical Relevance: Topical application of ozone gas may be effective in the early stages of oral wound healing.

A Step-By-Step Surgical Protocol for the Treatment of Perianal Fistula with Adipose-Derived Mesenchymal Stem Cells

Anal fistula is a challenging condition both for surgeons and patients. Recurrent fistula, Crohn's disease, or autoimmune disorders add further complexity to this situation. Numerous clinical trials have now demonstrated that cell-based therapy appears to be a good complement to fistulous surgery. As in any new treatment, especially that involving living cells, appropriate application is paramount to achieve optimal outcomes. As stem cell-based treatments are gaining a strong foothold in fistula management worldwide, we herein aim to share our mesenchymal stem cell surgical protocol. With the goal of optimizing results of this emerging therapy, we have improved and refined our protocol over the past 17 years of working with stem cells in clinical trials. The protocol consists of nine reproducible steps for mesenchymal stem cell application inside the fistulous tract, and has proven to be safe and effective in several studies, including international phase III clinical trials.

Influence of povidone-iodine on micro-tensile bonding strength to dentin under simulated pulpal pressure

Background

Previous studies had reported that bond strength deteriorate over time following the dentin surface pretreatment with chlorhexidine. Therefore, further investigations are needed to evaluate the effect of other materials such as povidone iodine.

The purpose of this study was to investigate the effects of 10% povidone-iodine pretreatment on the resin-dentin micro-tensile bond strength of a single bond adhesive system in permanent teeth over time, and compare it with 2% chlorhexidine.

Methods

Flat dentin surfaces were prepared in 63 extracted permanent teeth. Teeth were randomly assigned to a 10% povidone-iodine pretreatment, a 2% chlorhexidine pretreatment, or a control group. Composite resin blocks were built up over treated surfaces under pulp pressure simulation. The prepared specimens were assigned to three storage time, 24 h, 1 week, and 2 months. Samples were vertically sectioned to obtain specimens of 0.7 to 1.2 mm² cross-sectional area.

Results

No significant reduction of bond strength of povidone iodine group was found among the three storage times (p = 0.477). A significant reduction of bond strength for both chlorhexidine and control groups was found in the three storage times (p <  0.001).

Conclusion

Povidone iodine pretreatment of etched dentin was effective in reducing the loss of bond strength over time, while the chlorhexidine pretreatment and negative control showed significant deterioration in micro-tensile bond strength over time in permanent teeth.

Tailored antimicrobial activity and long-term cytocompatibility of plasma polymer silver nanocomposites

The deposition of coatings enabling antibacterial properties in combination with cytocompatibility remains a challenge for biomaterial applications, such as in medical devices. Silver is one of the most utilized antibacterial surface components, due to its efficacy and extensive applicability. In this work, silver-containing plasma polymer nanocomposites (single layer and multilayers) were developed and tested, with a focus on cytotoxicity and bactericidal function, on the NIH3T3 mammalian cell line as well as Gram-negative ( Pseudomonas aeruginosa) and Gram-positive ( Staphylococcus aureus) bacterial strains. The data demonstrate that a tuneable Ag⁺ release is required, allowing sufficient antimicrobial activity while retaining appropriate cytocompatibility over the entire testing period of up to eight days.

Cytotoxicity evaluation of chlorhexidine gluconate on human fibroblasts, myoblasts, and osteoblasts

Introduction: Chlorhexidine gluconate (CHX) is widely used as a preoperative surgical skin-preparation solution and intra-wound irrigation agent, with excellent efficacy against wide variety of bacteria. The cytotoxic effect of CHX on local proliferating cells following orthopaedic procedures is largely undescribed. Our aim was to investigate the in vitro effects of CHX on primary fibroblasts, myoblasts, and osteoblasts. Methods: Cells were exposed to CHX dilutions (0%, 0.002%, 0.02%, 0.2%, and 2%) for either a 1, 2, or 3-minute duration. Cell survival was measured using a cytotoxicity assay (Cell Counting Kit-8). Cell migration was measured using a scratch assay: a "scratch" was made in a cell monolayer following CHX exposure, and time to closure of the scratch was measured. Results: All cells exposed to CHX dilutions of ≥ 0.02% for any exposure duration had cell survival rates of less than 6% relative to untreated controls (p < 0.001). Cells exposed to CHX dilution of 0.002% all had significantly lower survival rates relative to control (p < 0.01) with the exception of 1-minute exposure to fibroblasts, which showed 96.4% cell survival (p = 0.78). Scratch defect closure was seen in < 24 hours in all control conditions. However, cells exposed to CHX dilutions ≥ 0.02% had scratch defects that remained open indefinitely. Conclusions: The clinically used concentration of CHX (2%) permanently halts cell migration and significantly reduces survival of in vitro fibroblasts, myoblasts, and osteoblasts. Further in vivo studies are required to examine and optimize CHX safety and efficacy when applied near open incisions or intra-wound application.

Efficacy of topical application of standardized extract of Tragopogon graminifolius in the healing process of experimental burn wounds

Tragopogon graminifolius DC. is a perennial plant from the family Asteraceae which grows in West parts of Iran. Several biological activities like antimicrobial, antioxidant and anti-inflammatory effects are reported for the plant. The aim of this study was to assess the wound healing activity of standardized extract from T. graminifolius (TG) aerial parts. Topical standardized TG extract with 5% and 10% concentrations in eucerine base was assessed for its healing properties on second degree burn in rats during a 14-day period. Biomarkers of oxidative damage including total antioxidant power, lipid peroxidation and total thiol molecules of the skin tissue samples were also evaluated. Results showed that 10%TG had the best efficacy with 80 ± 3% wound closure and tissue repair in comparison to negative control (p < 0.05). Significant reduction of tissue oxidative stress biomarkers was also observed. Histological analyses confirmed wound healing activity of TG extract, as well. Considering the antioxidative stress and anti-inflammatory activities of TG, explained by the high content of phenolic compounds of the plant, standardized TG extract could be considered as a natural remedy for the treatment of burn wounds. Further clinical studies are suggested to confirm the effectiveness of TG as a wound healing agent.

Chlorhexidine Antiseptic Irrigation Eradicates Staphylococcus epidermidis From Biofilm: An In Vitro Study

BACKGROUND

Antiseptic and antibacterial solutions used for intraoperative irrigation are intended to kill bacteria and thereby decrease the incidence of surgical site infections. It is unknown if the concentrations and exposure times of irrigation solutions commonly used for prophylaxis in clean cases (povidone-iodine 0.35% for 3 minutes) are effective against bacteria in biofilm that are present in implant infections. Currently, povidone-iodine (0.35%), chlorhexidine (0.05%), sodium hypochlorite (0.125%), and triple antibacterial solution are all being used off-label for wound irrigation after surgical débridement for orthopaedic infections.

QUESTIONS/PURPOSES

Do commonly used antibacterials and antiseptics kill bacteria in established biofilm at clinically relevant concentrations and exposure times?

METHODS

Staphylococcus epidermidis (ATCC#35984) biofilms were exposed to chlorhexidine (0.025%, 0.05%, and 0.1%), povidone-iodine (0.35%, 1.0%, 3.5%, and 10%), sodium hypochlorite (0.125%, 0.25%, and 0.5%,), and triple antibacterial solution (bacitracin 50,000 U/L, gentamicin 80 mg/L, and polymyxin 500,000 U/L) for 1, 5, and 10 minutes in triplicate. Surviving bacteria were detected by 21-day subculture. Failure to eradicate all bacteria in any of the three replicates was considered to be "not effective" for that respective solution, concentration, and exposure time.

RESULTS

Chlorhexidine 0.05% and 0.1% at all three exposure times, povidone-iodine 10% at all three exposure times, and povidone-iodine 3.5% at 10 minutes only were effective at eradicating S epidermidis from biofilm. All concentrations and all exposure times of sodium hypochlorite and triple antibacterial solution were not effective.

CONCLUSIONS

Chlorhexidine is capable of eradicating S epidermidis from biofilm in vitro in clinically relevant concentrations and exposure times. Povidone-iodine at commonly used concentrations and exposure times, sodium hypochlorite, and triple antibacterial solutions are not.

CLINICAL RELEVANCE

This in vitro study suggests that chlorhexidine may be a more effective irrigation solution for S epidermidis in biofilm than other commonly used solutions, such as povidone-iodine, Dakin's solution, and triple antibiotic solution. Clinical outcomes should be studied to determine the most effective antiseptic agent, concentration, and exposure time when intraoperative irrigation is used in the presence of biofilm.

Topical Antimicrobials in Burn Care: Part 1-Topical Antiseptics

Burn wounds disrupt the body's primary defense against invasion and colonization by microorganisms. Topical antimicrobials are one component in burn wound care. These agents suppress microbial growth to advantage skin cells and wound healing. Topical antimicrobials can be divided into 2 superclasses: antiseptics and antibiotics. We review the 4 main classes of topical antiseptics (emulsifiers, acids, oxidizers, and heavy metals) and antiseptic-impregnated dressings in current clinical use and address the mechanisms, as well as the advantages and disadvantages of each antiseptic for burn wound management.

Orthopaedic traumatology: fundamental principles and current controversies for the acute care surgeon

Multiply injured patients with fractures are co-managed by acute care surgeons and orthopaedic surgeons. In most centers, orthopaedic surgeons definitively manage fractures, but preliminary management, including washouts, splinting, reductions, and external fixations, may be performed by selected acute care surgeons. The acute care surgeon should have a working knowledge of orthopaedic terminology to communicate with colleagues effectively. They should have an understanding of the composition of bone, periosteum, and cartilage, and their reaction when there is an injury. Fractures are usually fixed urgently, but some multiply injured patients are better served with a damage control strategy. Extremity compartment syndrome should be suspected in all critically injured patients with or without fractures and a low threshold for compartment pressure measurements or empiric fasciotomy maintained. Acute care surgeons performing rib fracture fixation and other chest wall injury reconstructions should follow the principles of open fracture reduction and stabilization.

Povidone-iodine Solutions Inhibit Cell Migration and Survival of Osteoblasts, Fibroblasts, and Myoblasts

STUDY DESIGN

In vitro laboratory study.

OBJECTIVE

The purpose of this study was to identify the effect of dilute povidone-iodine (PVI) solutions on human osteoblast, fibroblast and myoblast cells in vitro.

SUMMARY OF BACKGROUND DATA

Dilute PVI wound lavage has been used successfully in spine and joint arthroplasty procedures to prevent postoperative surgical site infection, but their biologic effect on host cells is largely unknown.

METHODS

Human primary osteoblasts, fibroblasts, and myoblasts were expanded in cell culture and subjected to various concentrations of PVI (0%, 0.001%, 0.01%, 0.1%, 0.35%, 1%) for 3 minutes. To assess the effect of PVI on cell migration, a scratch assay was performed, in which a "scratch" was made by a standard pipette tip in a cell monolayer following PVI exposure, and time to closure of the scratch was evaluated. Cell survival and proliferation was measured 48 hours post-PVI exposure using a cell viability and cytotoxicity assay.

RESULTS

Closure of the scratch defect in all cell monolayers was achieved in <24 hours in untreated controls and following exposure to PVI concentrations <0.1%. The scratch defect remained open indefinitely following exposure to PVI concentrations of ≥0.1%. PVI concentrations <0.1% did not have significant effect on survival rates compared with control for all cell types. Cells exposed to PVI ≥ 0.1% had cell survival rates of less than 6% (P < 0.05).

CONCLUSIONS

Clinically used concentration of PVI (0.35%) exerts a pronounced cytotoxic effect on osteoblasts, fibroblast, and myoblasts in vitro. Further investigation is required to systematically study the effect of PVI on tissue healing in vivo and also determine a safe and clinically potent concentration for PVI lavage.

LEVEL OF EVIDENCE

N/A.

Sub-cytotoxic concentrations of ionic silver promote the proliferation of human keratinocytes by inducing the production of reactive oxygen species

Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions (Ag⁺) on the proliferation of human skin keratinocytes (HaCaT) and the production of intracellular reactive oxygen species (ROS). After treating HaCaT cells with Ag⁺ and/or the active oxygen scavenger N-acetyl cysteine (NAC), cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine (BrdU) incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen (PCNA) immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag⁺ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10^-6 and 10^-5 mol/L Ag⁺ at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5-60 min after exposure to Ag⁺. The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10^-6 and 10^-5 mol/L Ag⁺, with 10^-5 mol/L Ag⁺ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag⁺ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag⁺ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.

Antimicrobial Activity and Cell Selectivity of Synthetic and Biosynthetic Cationic Polymers

The mammalian and microbial cell selectivity of synthetic and biosynthetic cationic polymers has been investigated. Among the polymers with peptide backbones, polymers containing amino side chains display greater antimicrobial activity than those with guanidine side chains, whereas ethylenimines display superior activity over allylamines. The biosynthetic polymer ε-polylysine (εPL) is noncytotoxic to primary human dermal fibroblasts at concentrations of up to 2,000 μg/ml, suggesting that the presence of an isopeptide backbone has greater cell selectivity than the presence of α-peptide backbones. Both εPL and linear polyethylenimine (LPEI) exhibit bactericidal properties by depolarizing the cytoplasmic membrane and disrupt preformed biofilms. εPL displays broad-spectrum antimicrobial properties against antibiotic-resistant Gram-negative and Gram-positive strains and fungi. εPL elicits rapid bactericidal activity against both Gram-negative and Gram-positive bacteria, and its biocompatibility index is superior to those of cationic antiseptic agents and LPEI. εPL does not interfere with the wound closure of injured rabbit corneas. In a rabbit model of bacterial keratitis, the topical application of εPL (0.3%, wt/vol) decreases the bacterial burden and severity of infections caused by Pseudomonas aeruginosa and Staphylococcus aureus strains. In vivo imaging studies confirm that εPL-treated corneas appeared transparent and nonedematous compared to untreated infected corneas. Taken together, our results highlight the potential of εPL in resolving topical microbial infections.

The Effect of Antiseptics on Adipose-Derived Stem Cells

BACKGROUND

Although chemical antiseptics are the most basic measure to control wound infection and frequently come into contact with subcutaneous adipose tissue, no studies have evaluated their toxicity on adipose tissue and its cell fractions. In the present study, the effects of five different antiseptics on adipose-derived stem cells were evaluated.

METHODS

Human adipose-derived stem cells were harvested from healthy donors. Adipose-derived stem cell viability was measured after treatment with different concentrations of antiseptics over 5 days. Furthermore, the effect on the proliferation, adipogenic differentiation, and apoptosis/necrosis of adipose-derived stem cells was analyzed. Finally, the mRNA expression of the stem cell markers CD29, CD34, CD73, CD90, and CD105 was detected.

RESULTS

Octenisept and Betaisodona significantly reduced cell proliferation and differentiation and led to considerable adipose-derived stem cell necrosis. Octenisept decreased stem cell viability at the lowest concentrations tested, and all stem cell markers were down-regulated by Octeniseptr and Betaisodona. Lavasept and Prontosan both led to reduced stem cell viability, proliferation, and differentiation, and increased apoptosis/necrosis, although the effects were less pronounced compared with Octenisept and Betaisodona. Adipose-derived stem cells survived treatment with mafenide acetate even at high concentrations, and mafenide acetate showed minimal negative effects on their proliferation, adipogenic differentiation, cell death, and stem cell marker expression.

CONCLUSIONS

Mafenide acetate may be regarded as a feasible antiseptic for the treatment of wounds with exposed adipose tissue because of its low adipose-derived stem cell toxicity. Lavasept and Prontosan are possible alternatives to mafenide acetate. Octenisept and Betaisodona, by contrast, may be used only in highly diluted solutions.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Hydrogen Peroxide Wound Irrigation in Orthopaedic Surgery

As the burden of deep hardware infections continues to rise in orthopaedics, there is increasing interest in strategies for more effective debridement of colonized tissues and biofilm. Hydrogen peroxide has been used medically for almost a century, but its applications in orthopaedic surgery have yet to be fully determined. The basic science and clinical research on the antiseptic efficacy of hydrogen peroxide have demonstrated its efficacy against bacteria, and it has demonstrated potential synergy with other irrigation solutions such as chlorhexidine and povidone-iodine. While hydrogen peroxide is effective in infection reduction, there are concerns with wound healing, cytotoxicity, and embolic phenomena, and we recommend against hydrogen peroxide usage in the treatment of partial knee replacements, hemiarthroplasties, or native joints. Additionally, due to the potential for oxygen gas formation, hydrogen peroxide should not be used in cases of dural compromise, when pressurizing medullary canals, or when irrigating smaller closed spaces to avoid the possibility of air embolism. Finally, we present our protocol for irrigation and debridement and exchange of modular components in total joint arthroplasty, incorporating hydrogen peroxide in combination with povidone-iodine and chlorhexidine.

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.