Treatment of chronic, nonhealing abdominal wound in a liquid environment

A multifunctional sateen woven dressings for treatment of skin injuries

Cutaneous wounds with impaired healing such as diabetic ulcers and burns constitute major and rapidly growing threat to healthcare systems worldwide. Accelerating wound healing requires the delivery of biological factors that induce angiogenesis, support cellular proliferation, and modulate inflammation while minimizing infection. In this study, we engineered a dressing made by weaving of composite fibers (CFs) carrying mesenchymal stem cells (MSCs) and a model antibiotic using a scalable sateen textile technique. In this regard, two different sets of CFs carrying MSCs or an antimicrobial agent were used to generate a multifunctional dressing. According to cell viability and metabolic activity as CCK-8 and live/dead with qRT-PCR results, more than %90 the encapsulated MSCs remain viable for 28 days and their expression levels of the wound repair factors including ECM remodeling, angiogenesis and immunomodulatory maintained in MSCs post dressing manufacturing for 14 days. Post 10 days culture of the dressing, MSCs within CFs had 10-fold higher collagen synthesis (p < 0.0001) determined by hydroxyproline assay which indicates the enhanced healing properties. According to in vitro antimicrobial activity results determined by disk diffusion and broth microdilution tests, the first day and the total amount of release gentamicin loaded dressing samples during the 28 days were higher than determined minimal inhibition concentration (MIC) values for S. aureus and K. pneumonia without negatively impacting the viability and functionality of encapsulated MSCs within the dressing. The dressing is also flexible and can conform to skin curvatures making the dressing suitable for the treatment of different skin injuries such as burns and diabetic ulcers.

Topical Drug Delivery in the Treatment of Skin Wounds and Ocular Trauma Using the Platform Wound Device

Topical treatment of injuries such as skin wounds and ocular trauma is the favored route of administration. Local drug delivery systems can be applied directly to the injured area, and their properties for releasing therapeutics can be tailored. Topical treatment also reduces the risk of adverse systemic effects while providing very high therapeutic concentrations at the target site. This review article highlights the Platform Wound Device (PWD) (Applied Tissue Technologies LLC, Hingham, MA, USA) for topical drug delivery in the treatment of skin wounds and eye injuries. The PWD is a unique, single-component, impermeable, polyurethane dressing that can be applied immediately after injury to provide a protective dressing and a tool for precise topical delivery of drugs such as analgesics and antibiotics. The use of the PWD as a topical drug delivery platform has been extensively validated in the treatment of skin and eye injuries. The purpose of this article is to summarize the findings from these preclinical and clinical studies.

Delivery of topical gentamicin cream via platform wound device to reduce wound infection—A prospective, controlled, randomised, clinical study

The platform wound device (PWD) is a wound coverage system that is designed to decrease wound infection rates by allowing for direct delivery of topical antibiotics and antimicrobials while creating a sealed, protective barrier around the area of injury. This study evaluated the safety and efficacy of the PWD as a protective dressing and a delivery system for topical antibiotics compared to the current standard of care (SoC). This was a multi-center, prospective, randomised, controlled clinical trial. The wounds were treated with the PWD with gentamicin cream or SoC dressings. The wounds were evaluated before the start of treatment and after 48-96 hours via clinical assessment, photographs, and qualitative bacterial swabs for bacterial analysis. The delivery of gentamicin via the PWD was safe and did not cause any adverse effects. The treatment decreased both inflammation and bacterial growth during the study period. No significant differences in the SoC were observed. The PWD is a transparent and impermeable polyurethane chamber that encloses and protects the injured area. The delivery of topical gentamicin via the PWD was safe and effective. Clinical assessment for infection found the PWD to be non-inferior to the current SoC treatment options.

Moist Wound Healing with Commonly Available Dressings

Significance: A moist wound environment has several benefits that result in faster and better quality of healing. It facilitates autolytic debridement, reduces pain, reduces scarring, activates collagen synthesis, facilitates and promotes keratinocyte migration over the wound surface, and supports the presence and function of nutrients, growth factors, and other soluble mediators in the wound microenvironment. Recent Advances: Wound dressings can be utilized to create, maintain, and control a moist environment for healing. Moist wound dressings can be divided into films, foams, hydrocolloids, hydrogels, and alginates. We are also including negative pressure wound therapy systems in the moist dressings. Critical Issues: An optimal wound dressing should provide a moist environment and have an optimal water vapor transmission rate (WVTR) and absorptive capacity. It should also protect the wound against trauma and contamination and be easy to apply, painless to remove, and esthetically acceptable or even pleasing. Future Directions: Interventions, particularly dressing changes, by medical caregivers are labor intensive and expensive and there should be a continuous effort to reduce their number per week. Smart dressings with integrated microsensors and delivery capabilities that would allow wireless real-time monitoring and treatment of the wound would be very advantageous. This way the state of the wound as well as the wear time of the dressing could be assessed without dressing removal or visit to the wound care center. In addition, an ability to adjust the WVTRs to the exudate level of the wound (or having a large absorptive capacity without changing the WVTR) would be useful. This feature would guarantee an optimal level of hydration of the wound surface throughout the treatment.

Antibiotic-Containing Agarose Hydrogel for Wound and Burn Care

Wound infections cause inflammation, tissue damage, and delayed healing that can lead to invasive infection and even death. The efficacy of systemic antibiotics is limited due to poor tissue penetration that is especially a problem in burn and blast wounds where the microcirculation is disrupted. Topical administration of antimicrobials is an attractive approach because it prevents infection and avoids systemic toxicity, while hydrogels are an appealing vehicle for topical drug delivery. They are easy to apply to the wound site by being injectable, the drug release properties can be controlled, and their many characteristics, such as biodegradation, mechanical strength, and chemical and biological response to stimuli can be tailored. Hydrogels also create a moist wound environment that is beneficial for healing. The purpose of this study was to formulate an agarose hydrogel that contains high concentrations of minocycline or gentamicin and study its characteristics. Subsequently, the minocycline agarose hydrogel was tested in a porcine burn model and its effect as a prophylactic treatment was studied. The results demonstrated that 0.5% agarose in water was the optimal concentration in terms of viscosity and pH. Bench testing at room temperature demonstrated that both antibiotics remained stable in the hydrogel for at least 7 days and both antibiotics demonstrated sustained release over the time of the experiment. The porcine burn experiment showed that prophylactic treatment with the agarose minocycline hydrogel decreased the burn depth and reduced the number of bacteria as efficiently as the commonly used silver sulfadiazine cream.

The use of moist exposed burn ointment (MEBO) for the treatment of burn wounds: a systematic review

Moist exposed burn ointment (MEBO) is an oil-based herbal paste, purported to be efficacious in managing burn wounds and more commonly used in Asia and the Middle East. A PRISMA-compliant systematic review was performed to analyse the evidence for the use of MEBO on burn wounds. Wound healing rate was the primary outcome of interest. PubMed-listed randomised controlled trials (RCTs) comparing the efficacy of MEBO with placebo, standard care or other therapies in the treatment of partial thickness burns in adults and children were eligible for inclusion (November 2019). Six RCTs were eligible. The majority of trials comparing wound healing between MEBO and SSD favoured MEBO (two of three). There may be improved healing in MEBO-treated wounds vs. those treated with povidone-iodine + bepanthenol cream. There was no difference between MEBO and Acquacel Ag, but Helix Aspersa had faster healing rates than MEBO. However, all evidence was from moderately to poorly reported trials with a high risk of bias, thereby limiting the strength of this evidence. In conclusion, the evidence for MEBO in English-language literature was poor and inconsistent with respect to wound healing rate and analgesis compared to 1% SSD, Acquacel Ag, Helix aspersa cream and povidone-iodine + bepanthenol cream. Blinded RCTs comparing MEBO to both placebo and other common topical treatments may further improve the confidence in concluding their analysis. There is some evidence that MEBO is as safe as its comparators as shown by the low complication rate.

Immediate Treatment of Burn Wounds with High Concentrations of Topical Antibiotics in an Alginate Hydrogel Using a Platform Wound Device

Objective: There is an unmet need to improve immediate burn care, particularly when definitive treatment is delayed. Therefore, the purpose of this project was to formulate a hydrogel that contains very high concentrations of antibiotics and validate its use together with a platform wound device (PWD) for the immediate care of burns. Approach: The hydrogel properties were optimized by using a rheometer, differential scanning calorimetry, and liquid chromatography-mass spectrometry and were tested in an infected porcine burn model. Immediately, after burn creation, the burns were infected with different bacteria. Subsequently, the burns infected with Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii were covered with the PWD and treated with a single dose of hydrogel containing 1000 × minimum inhibitory concentration of vancomycin, gentamicin, and minocycline, respectively. On day 7 or 45, the animals were euthanized, and the burns were harvested for histology and quantitative bacteriology. Results: 0.625% was the best alginate concentration for the hydrogel in terms of viscosity, stability, and drug release. The porcine studies demonstrated that vancomycin-, gentamicin-, and minocycline-treated tissues contained significantly less bacteria and reduced depth of tissue necrosis in comparison to controls. Innovation: The PWD represents a platform technology that begins at the point of the first treatment by protecting the wound and allowing administration of topical therapeutics. The device can be adapted to enclose any size burn over any contour of the body. Conclusion: Antibiotics can be delivered safely in very high concentrations in a hydrogel using the PWD, and burn infections can be treated successfully with this method.

Current preventive measures for health-care associated surgical site infections: a review

Healthcare-associated infections (HAIs) continue to be a tremendous issue today. It is estimated 1.7 million HAIs occur per year, and cost the healthcare system up to $45 billion annually. Surgical site infections (SSIs) alone account for 290,000 of total HAIs and approximately 8,000 deaths. In today's rapidly changing world of medicine, it is ever important to remain cognizant of this matter and its impact both globally and on the individual lives of our patients. This review aims to impress upon the reader the unremitting significance of HAIs in the daily practice of medicine. Further, we discuss the etiology of HAIs and review successful preventive measures that have been demonstrated in the literature. In particular, we highlight preoperative, intraoperative, and postoperative interventions to combat SSIs. Finally, we contend that current systems in place are often insufficient, and emphasize the benefits of institution-wide adoption of multiple preventive interventions. We hope this concise update and review can inspire additional dialogue for the continuing progress towards improving patient care and patient lives.

The expression of proinflammatory genes in epidermal keratinocytes is regulated by hydration status

Mucosal wounds heal more rapidly, exhibit less inflammation, and are associated with minimal scarring when compared with equivalent cutaneous wounds. We previously demonstrated that cutaneous epithelium exhibits an exaggerated response to injury compared with mucosal epithelium. We hypothesized that treatment of injured skin with a semiocclusive dressing preserves the hydration of the skin and results in a wound healing phenotype that more closely resembles that of mucosa. Here we explored whether changes in hydration status alter epidermal gene expression patterns in rabbit partial-thickness incisional wounds. Using microarray studies on injured epidermis, we showed that global gene expression patterns in highly occluded versus non-occluded wounds are distinct. Many genes including IL-1β, IL-8, TNF-α (tumor necrosis factor-α), and COX-2 (cyclooxygenase 2) are upregulated in non-occluded wounds compared with highly occluded wounds. In addition, decreased levels of hydration resulted in an increased expression of proinflammatory genes in human ex vivo skin culture (HESC) and stratified keratinocytes. Hierarchical analysis of genes using RNA interference showed that both TNF-α and IL-1β regulate the expression of IL-8 through independent pathways in response to reduced hydration. Furthermore, both gene knockdown and pharmacological inhibition studies showed that COX-2 mediates the TNF-α/IL-8 pathway by increasing the production of prostaglandin E2 (PGE2). IL-8 in turn controls the production of matrix metalloproteinase-9 in keratinocytes. Our data show that hydration status directly affects the expression of inflammatory signaling in the epidermis. The identification of genes involved in the epithelial hydration pathway provides an opportunity to develop strategies to reduce scarring and optimize wound healing.

Effect of Polyvinylpyrrolidone-Iodine Liposomal Hydrogel on Wound Microcirculation in SKH1-hr Hairless Mice

AIM

Polyvinylpyrrolidone-iodine liposomal hydrogel (PVP-ILH) is a hydrogel formulation based on polyvinylpyrrolidone-iodine (PVP-I) and liposomes. The beneficial effects of PVP-ILH on wound healing have been previously shown. The aim of this study was to investigate the effects of topically applied PVP-ILH on wound microcirculation.

MATERIALS AND METHODS

Experiments were performed on wounds in male SKH1-hr hairless mice (n = 48). Mice were randomized into five treatment groups: mice treated with polyacrylic acid (PAA) and PAA 1:10 as well as PVP-ILH and PVP-ILH 1:10. Mice treated with sodium chloride served as control. Immediately as well as 3, 7, and 14 days after wounding, intravital fluorescent microscopy (IFM) was performed to determine wound surface area and standard microcirculatory parameters.

RESULTS

Topically administered PVP-ILH reduced wound size significantly faster compared to controls. Standard microcirculatory parameters, e.g. functional capillary density (FCD) and plasma leakage, showed no differences. FCD increases in all groups after wound creation. Using PVP-ILH, a trend towards higher FCD was observed.

CONCLUSION

The wound model in hairless mice in combination with IFM is suitable to qualitatively assess wound microcirculation over a period of 2 weeks even after topical application of pigmented ointments. PVP-ILH showed a positive effect on dermal wound healing and wound microcirculation.

Gene therapy in the treatment of lower extremity wounds

This article presents a brief overview of the etiology of chronic wounds of the lower extremities and their current medical and surgical treatment. Gene therapy as a potential tool for treating therapeutically challenging wounds is described in terms of the vectors employed in gene transfer, as well as the strategies used to promote wound healing. Results from animal model studies, as well as clinical trials, are presented.

Wet wound healing: from laboratory to patients to gene therapy

Wet treatment of wounds has been used as an "irrigation" method since the seventh century. We have developed the concept of an in vivo tissue culture that facilitates wound healing and allows tissue engineering. A transparent, flexible, round chamber provides the wet environment. This system heals clean wounds as fast or faster than any other method, with less scarring. It allows delivery of analgesics, antibiotics, growth factors, growth media, and cells into the chamber, becoming a platform for tissue engineering. Gene therapy of the wound can be done in the chamber with growth factor and other genes. A tetracycline switch allows precise timing and amounts of expression and provides the opportunity for sequential expression of genes delivered at the same time.

Moist exposed therapy: an effective and valid alternative to occlusive dressings for postlaser resurfacing wound care

BACKGROUND

Laser resurfacing has now become an accepted and important component of facial rejuvenation. With the introduction of computerized scanning systems, the actual laser resurfacing technique has been greatly simplified; however, the final outcome still depends to a large extent on the efficiency of the postlaser wound care in promoting wound healing and preventing early and late complications. It has been repeatedly confirmed that a moist environment is the single most important external factor affecting the rate of re-epithelialization. Occlusive moisture-retentive dressings, however, are difficult to apply and maintain in position and may as well be complicated by serious infections.

OBJECTIVE

Moist exposed burn ointment has been shown to maintain adequate moisture for optimal healing by frequent ointment application without the need for a secondary overlying dressing. It would be ideal for postoperative laser care.

METHODS

Twenty-eight consecutive patients treated with coherent ultrapulse CO2 laser in Toulouse, France, were included in the trial. Moisture-retentive ointment was applied over the treated areas every 4 to 6 hours. Healing was assessed clinically and with repeated transepidermal water loss measurements. Swab cultures were taken, and pain was evaluated with a visual analog scale. Colorimetric analysis of pictures taken was statistically compared with picture analysis of 20 patients treated earlier with an occlusive dressing.

RESULTS

Uneventful timely healing occurred in all patients with minimal pain and discomfort. Healing with moist exposed therapy resulted in faster recovery of cutaneous erythema, as evidenced by colorometry.

CONCLUSION

Moist exposed burn ointment application can be safely considered a good and valid alternative to occlusive dressings for postoperative laser care.

Scar quality and physiologic barrier function restoration after moist and moist-exposed dressings of partial-thickness wounds

BACKGROUND

There is growing evidence of improved healing of full- and partial-thickness cutaneous wounds in wet and moist environments. Retention of biologic fluids over the wound prevents desiccation of denuded dermis or deeper tissues and allows faster and unimpeded migration of keratinocytes over the wound surface. It allows also the naturally occurring cytokines and growth factors to exert their beneficial effect on wound contracture and re-epithelialization. Despite all of these documented benefits, applying the moist healing principles to large surface areas, in particular to large burns, is hindered by the major technical handicap of creating and maintaining a sealed moist environment over these areas.

METHODS

From January to September 2001, healing of partial-thickness skin graft donor sites was studied in a prospective comparative study of two types of moist dressings, Tegaderm (3M Health Care, St. Paul, MN), a semipermeable membrane occlusive dressing, and moist exposed burn ointment (MEBO) (Julphar; Gulf Pharmaceutical Industries, United Arab of Emirates), an ointment that can provide a moist environment without the need of an overlying occlusive dressing. Healing was assessed both clinically and with serial measurements of transepidermal water loss (TEWL) and moisture. Following healing, scar quality was evaluated by two members of the team separately using a visual analog scale. Results were statistically analyzed.

RESULTS

Faster healing was observed clinically with MEBO application. Physiologic healing as determined by TEWL measurements occurred at an extremely significant earlier stage for MEBO, and this was associated with better scar quality, demonstrating a positive relationship between function and cosmetic appearance. Moreover, the ointment is definitely easier to apply than the occlusive self-adhesive membrane, which requires some degree of dexterity and expertise.

CONCLUSION

MEBO application is an effective and valid alternative to conventional occlusive dressings. Moreover, the observed improved anatomic and physiologic healing indicates that MEBO may have a positive effect on healing more that the mere fact of passive moisture retention.

Tissue engineering of skin

The skin plays a crucial role in protecting the integrity of the body's internal milieu. The loss of this largest organ is incompatible with sustained life. In reconstructive surgery or burn management, substitution of the skin is often necessary. In addition to traditional approaches such as split- or full-thickness skin grafts, tissue flaps and free-tissue transfers, skin bioengineering in vitro or in vivo has been developing over the past decades. It applies the principles and methods of both engineering and life sciences toward the development of substitutes to restore and maintain skin structure and function. Currently, these methods are valuable alternatives or complements to other techniques in reconstructive surgery. This review article deals with the evolution and current approaches to the development of in vitro and in vivo epidermis and dermis.