Dressings, Topical Therapy, and Negative Pressure Wound Therapy

A novel hydrogel containing 4-methylcatechol for skin regeneration: in vitro and in vivo study

Skin damages are usual physical injuries and different studies have been done to improve wound healing. Hydrogel due to its properties like a moist environment and cooling wound site is a good option for wound treatment. In this study, we evaluated the consequence of using alginate/chitosan hydrogel contained various dosages of 4-Methylcatechol (0, 0.1, 1% (W/W)) on wound healing. After hydrogel fabrication, different tests like SEM, swelling, release, weight loss, and hemo- and cytocompatibility were done to characterize fabricated hydrogels. Finally, the rat model was used to assess Alginate/Chitosan hydrogel's therapeutic function containing 0.1 and 1% of 4-Methylcatechol. The pore size of hydrogel was between 24.5 ± 9 and 62.1 ± 11.63 µm and about 90% of hydrogel was lost after 14 days in the weight loss test. Blood compatibility and MTT assay showed that hydrogels were nontoxic and improved cell proliferation. In vivo test showed that Alginate/Chitosan/0.1%4-Methylcatechol improved wound healing and the results were significantly better than the gauze-treated wound. Our results showed dose depending effect of 4-Methylcatechol on wound healing. This study shows the treatment effect of 4-Methylcatechol on wound healing and the possibility of using it for treating skin injuries.

Antibacterial Hydrogel Sheet Dressings Composed of Poly(vinyl alcohol) and Silver Nanoparticles by Electron Beam Irradiation

Advanced wound dressings that can deliver potent antibacterial action are still much in need, especially for treating wound infections caused by drug-resistant bacteria. In this research, we utilized electron beam (EB) irradiation to develop antibacterial hydrogel sheet dressings from poly(vinyl alcohol) (PVA) and silver nanoparticles (AgNPs) in a two-step processing and evaluated their bactericidal efficacy, as well as the AgNP release. The effect of the irradiation dose on the swelling, gel fraction, network parameters, and mechanical properties of the hydrogels was first determined to establish the optimal doses for the two-step processing. The prototypic hydrogel sheets were then formed in the first EB irradiation and served as a matrix for the AgNP synthesis by the reduction of the silver nitrate precursors during the second EB irradiation. The diffusion assay showed that the minimal inhibition concentration (MIC) of the AgNP-load hydrogels was 0.25 and 0.5 mg/cm2 against Escherichia coli and Staphylococcus aureus, respectively. At these MIC levels, the released AgNPs increased sharply before reaching the maximum, ~950 and 1800 ppb, at 24 h as analyzed by atomic absorption. Therefore, we successfully demonstrated that this two-step processing by EB irradiation provides a convenient platform to fabricate AgNP-loaded hydrogel dressings that can be further developed for wound healing.

Tissue healing changes on wounds in rats after treatment with Hancornia speciosa latex in cream-gel formulation

PURPOSE

Hancornia speciosa latex has shown pharmacological potential in wound healing processes due to its angiogenic, osteogenic, and anti-inflammatory activities. The aims of this study were to carry out a cream-gel formulation with 5, 10 and 25% of H. speciosa serum latex and to evaluate its potential to stimulate the skin regeneration in rats' wounds.

METHODS

One hundred and twenty rats were divided into five groups: neutral control with saline (G1), cream-gel based on H. speciosa latex serum at 5% m/v (G2), cream-gel at 15% m/v (G3), cream-gel at 25% m/v (G4), and cream-gel (G5). The animals were euthanized at three, seven, 14 and 21 days after the injury induction, and some parameters were analyzed: wound contraction, necrosis, fibrin, polymorphonuclear and mononuclear infiltrates, fibroblast, angiogenesis, hemorrhage, and collagen.

RESULTS

The therapeutic treatment with cream-gel at 15 and 25% is beneficial in the inflammatory phase of healing processes since it increased the angiogenesis and proliferation of mononuclear infiltrations in wounds. Regarding wound contraction, the treatment with cream-gel (5 and 15%) induced a higher rate of contraction in the proliferative phase. The 15% cream-gel formulation stimulated a greater production of collagen in the injured tissues.

CONCLUSIONS

H. speciosa cream-gel is a low-cost herbal medicine which can aid in tissue repair.

Waterproof dressing combined with sodium chloride to promote healing in acute wounds: a case report from an Indonesian hospital

In this case study, the wound healing process of a patient who had undergone an appendectomy and whose wound was treated with waterproof dressing was analysed, and the coverage of granulation tissue was tracked. This study aimed to re-evaluate the use of waterproof dressing, combined with sodium chloride, on acute wounds in an Indonesian hospital. Data were collected and evaluated through the use of the Nursing Outcomes Classification (NOC) observation method. A waterproof dressing and sodium chloride (NaCl) were administered once every 2 days to promote wound healing. After three rounds (14 days) of using waterproof dressing, granulation tissue formed over the surface of the wound base. The end result of healing by primary intention was complete return to function, with minimal scarring and loss of skin appendages. Waterproof dressing was considered to be effective and characterised by the formation of 93.2% granulation tissue; epithelialisation was observed covering between 75-100% of the wound area. No complications occurred during the intervention.

Enhancing wound healing dressing development through interdisciplinary collaboration

The process of wound healing includes four phases: Hemostasis, inflammation, proliferation, and remodeling. Many wound dressings and technologies have been developed to enhance the body's ability to close wounds and restore the function of damaged tissues. Several advancements in wound healing technology have resulted from innovative experiments by individual scientists or physicians working independently. The interplay between the medical and scientific research fields is vital to translating new discoveries in the lab to treatments at the bedside. Tracing the history of wound dressing development reveals that there is an opportunity for deeper collaboration between multiple disciplines to accelerate the advancement of novel wound healing technologies. In this review, we explore the different types of wound dressings and biomaterials used to treat wounds, and we investigate the role of multidisciplinary collaboration in the development of various wound management technologies to illustrate the benefit of direct collaboration between physicians and scientists.

Skin wounds, the healing process, and hydrogel-based wound dressings: a short review

Skin wounds are damage to the epithelial layer and the integrity of living tissue. The healing mechanism is dynamic and complex, and often treatments with wound dressings help in tissue regeneration, reducing the risk of infections. Polymeric hydrogels become good candidates for wet curing process. These materials prevent dehydration of the tissue and avoid discomfort to the patient when changing the dressing. In this short review, we demonstrate the importance of the healing process, the types of skin wounds, and the hydrogels that are potentially attractive as wound dressings.

Comparison of closed incision negative pressure wound therapy with conventional dressing for reducing wound complications in emergency laparotomy

OBJECTIVE

The aim of this study was to compare the post-operative effects of closed incision negative pressure wound therapy with conventional dressing in emergency laparotomy.

METHODS

This study was conducted from 1st November 2018 to 31st March 2020 in ABVIMS & Dr. R.M.L. Hospital, New Delhi. The potential candidates for the study were patients of 18 years and above who were admitted in surgical emergency and underwent emergency laparotomy by a midline incision. Fifty random patients were alternatively allotted to group A (25 patients) and group B (25 patients). In the patients of group A, closed incision negative pressure wound therapy (ciNPWT) was applied on midline closed wound after an exploratory laparotomy procedure. The patients in group B, standard dry gauze dressing was done.

RESULTS

The mean age of patients in group A and group B were 46.76±12.20 and 41.96±8.33 years, respectively (p-value-0.11). The wound infection was present in 12% of cases in group A and 32% in group B, but when we calculate the p-value, it was found to be statistically non-significant (p-value-0.08). Similarly, seroma formation and wound dehiscence were found less in group A as compared to group B but not reached up to a statistically significant limit (p-value 0.55 and 0.38 respectively). The frequency of dressing change was 1-2 per week in 92% of cases in group A while it was 3-4 per week in 68% of cases in group B. The mean time of the frequency of dressing change was 1.24±0.72 per week and 4.28±1.90 per week in both the groups respectively (p-value <0.001). There was no significant (p>0.05) difference in the duration of hospital stay between group A (mean hospital stay 8.20±2.34 days) and group B (mean hospital stay 8.21±3.37 days).

CONCLUSION

Closed incision negative pressure wound therapy has no advantages over conventional dressing in terms of post-operative complications and hospital stay. However, it reduces the frequency of dressing change significantly, which reduces the mental stress of the patient and the burden of changing daily dressing.

Negative pressure wound therapy promotes wound healing by suppressing macrophage inflammation in diabetic ulcers

Aim: This work aims to explore the biological role of negative pressure wound therapy (NPWT) in the treatment of diabetic ulcer. Materials & methods: Full-thickness skin defects were created in diabetic (db/db) and non diabetic (db/m) mice to create wound models. The mice were received NPWT or rapamycin injection. Mouse macrophage cells (Raw264.7) were treated with lipopolysaccharide to induce inflammatory response, and then received negative pressure treatment. We observed the wound healing of mice and examined gene and protein expression and CD68⁺ macrophage levels. Results: NPWT notably enhanced the wound closure ratio, and inhibited the LC3-II/LC3-I ratio and Beclin-1 expression in diabetes mellitus (DM) mice. NPWT decreased CD68⁺ macrophage levels in wound tissues of DM mice. The influence conferred by NPWT was abolished by rapamycin treatment. Negative pressure repressed the LC3-II/LC3-I ratio and the expression of Beclin-1, TNF-α, IL-6 and IL-1β in the Raw264.7 cells. Conclusion: NPWT promotes wound healing by suppressing autophagy and macrophage inflammation in DM.

Cellular benefits of single-use negative pressure wound therapy demonstrated in a novel ex vivo human skin wound model

Negative pressure wound therapy is a widely used treatment for chronic, nonhealing wounds. Surprisingly, few studies have systematically evaluated the cellular and molecular effects of negative pressure treatment on human skin. In addition, no study to date has directly compared recently available single-use negative pressure modalities to traditional negative pressure devices in a controlled setting. Here we developed a novel large-scale ex vivo human skin culture system to effectively evaluate the efficacy of two different negative pressure wound therapy modalities. Single-use and traditional negative pressure devices were applied to human ex vivo wounded skin sheets cultured over a period of 48 hours. Cellular tissue response to therapy was evaluated via a combination of histological analysis and transcriptional profiling, in samples collected from the wound edge, skin adjacent to the wound, and an extended skin region. Single-use negative pressure wound therapy caused less damage to wound edge tissue than traditional application, demonstrated by improved skin barrier, reduced dermal-epidermal junction disruption and a dampened damage response. Transcriptional profiling confirmed significantly less activation of multiple pro-inflammatory markers in wound edge skin treated with single-use vs traditional negative pressure therapy. These findings may help to explain the greater efficacy of sNPWT in the clinic, while offering a noninvasive system to develop improved NPWT-based therapies.

Polyvinyl alcohol/chitosan wound dressings loaded with antiseptics

Wound care remains a challenge in healthcare. This work aimed to develop a new polyvinyl alcohol (PVA)/chitosan (Ch) based wound dressing able to ensure protection, hydration and a controlled release of antiseptics, as alternative to actual treatments. Two distinct formulations (1:1 and 3:1, w/w) were prepared, sterilized by autoclaving and characterized concerning surface morphology, degradation over the time, mechanical properties and hydrophilicity. Both dressings revealed adequate properties for the intended purpose. The dressings were loaded with chlorhexidine (CHX) and polyhexanide (PHMB) and the drug release profiles were determined using Franz diffusion cells. The release of PHMB was more sustained than CHX, lasting for 2 days. As the amounts of drugs released by PVA/Ch 1:1 were greater, the biological tests were done only with this formulation. The drug loaded dressings revealed antibacterial activity against S. aureus and S. epidermidis, but only the ones loaded with PHMB showed adequate properties in terms of cytotoxicity and irritability. The application of this elastic dressing in the treatment of wounds in a dog led to faster recovery than conventional treatment, suggesting that the material can be a promising alternative in wound care.

Consensus on the diagnosis and management of chronic leg ulcers - Brazilian Society of Dermatology

BACKGROUND

Chronic leg ulcers affect a large portion of the adult population and cause a significant social and economic impact, related to outpatient and hospital care, absence from work, social security expenses, and reduced quality of life. The correct diagnosis and therapeutic approach are essential for a favorable evolution.

OBJECTIVE

To gather the experience of Brazilian dermatologists, reviewing the specialized literature to prepare recommendations for the diagnosis and treatment of the main types of chronic leg ulcers.

METHODS

Seven specialists from six university centers with experience in chronic leg ulcers were appointed by the Brazilian Society of Dermatology to reach a consensus on the diagnosis and therapeutic management of these ulcers. Based on the adapted DELPHI methodology, relevant elements were considered in the diagnosis and treatment of chronic leg ulcers of the most common causes; then, the recent literature was analyzed using the best scientific evidence.

RESULTS

The following themes were defined as relevant for this consensus - the most prevalent differential etiological diagnoses of chronic leg ulcers (venous, arterial, neuropathic, and hypertensive ulcers), as well as the management of each one. It also included the topic of general principles for local management, common to chronic ulcers, regardless of the etiology.

CONCLUSION

This consensus addressed the main etiologies of chronic leg ulcers and their management based on scientific evidence to assist dermatologists and other health professionals and benefit the greatest number of patients with this condition.

Are Antimicrobial Peptide Dendrimers an Escape from ESKAPE?

Significance: The crisis of antimicrobial resistance (AMR) increases dramatically despite all efforts to use available antibiotics or last resort antimicrobial agents. The spread of the AMR, declared as one of the most important health-related issues, warrants the development of new antimicrobial strategies. Recent Advances: Antimicrobial peptides (AMPs) and AMP dendrimers (AMPDs), as well as polymer dendrimers are relatively new and promising strategies with the potential to overcome drug resistance issues arising in ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) colonizing chronic wounds. Critical Issues: AMPs-AMPDs suffer from limited efficacy, short-lasting bioactivity, and concerns of toxicity. To circumvent these drawbacks, their covalent coupling to biopolymers and/or encapsulation into different drug carrier systems is investigated, with a special focus on topical applications. Future Directions: Scientists and the pharmaceutical industry should focus on this challenging subject to either improve the activity of existing antimicrobial agents or find new drug candidates. The focus should be put on the discovery of new drugs or the combination of existing drugs for a better synergy, taking into account all kinds of wounds and existing pathogens, and more specifically on the development of next-generation antimicrobial peptides, encompassing the delivery carrier toward improved pharmacokinetics and efficacy.

Preparation and Properties of Minocycline-Loaded Carboxymethyl Chitosan Gel/Alginate Nonwovens Composite Wound Dressings

As derivatives from marine natural biomaterials, alginate-based and chitosan-based biomaterials are commonly used in wound dressings. Calcium alginate fiber (CAF) dressings possess excellent absorption and unique gel forming performance, but the low bioactivity limits its application in wound healing. Carboxymethyl chitosan (CM-Chit) has excellent antibacterial activity, but the gel structure with weak mechanical properties restricts its application. In this study, minocycline (Mino)/CM-Chit solution was coated on the surface of plasma treated CAF needle-punched nonwovens, and then Mino loaded CM-Chit gel/CAF nonwovens composite dressings were fabricated by EDC/NHS (1-3-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide) crosslinking. The dressings had a porous composite structure, which allowed them to quickly absorb and store a large number of wound exudates. Skin-like tensile performance allowed the dressings to provide a better healing environment. Antibacterial assay against Escherichia coli and Staphylococcus aureus indicated that the addition of Mino significantly improved the antibacterial activity of the wound dressings. The tight structure of CM-Chit gel prevented the burst release of Mino so that the dressings had antibacterial activity in a certain period of release time. Cell culture assay showed that the dressings had excellent cell biocompatibility. As new functional dressings, the prepared composite dressings had excellent potential in the clinical healing of wounds.