Development of a PHMB hydrogel‐modified wound scaffold dressing with antibacterial activity

Current wound scaffold dressing constructs can facilitate wound healing but do not exhibit antibacterial activity, resulting in high infection rates. We aimed to endow wound scaffold dressing with anti‐infective ability by polyhexamethylenebiguanide (PHMB). We prepared PHMB hydrogel at varying concentrations (0.25%, 0.5%, 1%, 2%) and assessed release and cytotoxicity. PHMB hydrogel was added to the wound scaffold dressing to generate a PHMB hydrogel‐modified wound scaffold dressing. Wound healing and infection prevention were evaluated using a full‐thickness skin defect model in rats. In vitro, the hydrogel PHMB release time positively correlated with PHMB concentration, with 1% allowing sufficiently long release time to encompass the high‐incidence period (3‐5 days) of infection following wound scaffold dressing implantation. Implantation of 1% PHMB hydrogel into the skin did not cause adverse responses. in vitro cytotoxicity assays showed the PHMB hydrogel‐modified wound scaffold dressing did not significantly affect proliferation of fibroblasts or vascular endothelial cells, 99.90% vs 99.84% for fibroblasts and 100.21% vs 99.28% for vascular endothelial cells at 21 days. Transplantation of PHMB hydrogel‐modified wound scaffold dressing/unmodified wound scaffold dressing on the non‐infected wounds of rats yielded no significant difference in relative vascularization rate, 47.40 vs 50.87 per view at 21 days, whereas bacterial content of the wound tissue in the PHMB hydrogel‐modified wound scaffold dressing group was significantly lower than the unmodified wound scaffold dressing group, (1.80 ± 0.35) × 10³ vs (9.34 ± 0.45) × 10³ at 14 days. Prevalence of persistent wound infection in the rats receiving PHMB hydrogel‐modified wound scaffold dressing transplantation onto infected wounds was significantly lower than the unmodified wound scaffold dressing group, 30% vs 100%. PHMB hydrogel‐modified wound scaffold dressing exhibited suitable antibacterial ability, and its biological activity did not significantly differ from that of the unmodified wound scaffold dressing, thereby allowing it to effectively prevent infection following wound scaffold dressing implantation.     

NF-κB and COX-2 repression with topical application of hesperidin and naringin hydrogels augments repair and regeneration of deep dermal wounds

IntroductionWound injury is common and causes serious complications if not treated properly. The moist dressing heals wounds faster than other dressings. Therefore, we sought to study the effect of hesperidin/naringin hydrogel wound dressing or their combinations on the deep dermal wounds in mice.MethodsA rectangular full thickness skin flap of 2.5 × 1.5 cm was excised from depilated mice dorsum and the wound was fully covered with 5% hesperidin/5% naringin hydrogel or both in the ratio of 1:1, 2:1, or 1:2, respectively once daily until complete healing of the wound. Data were collected on wound contraction, mean wound healing time, collagen, DNA, and nitric oxide syntheses, glutathione concentration, superoxide dismutase activity, and lipid peroxidation throughout healing. Expression of NF-κB and COX-2 were also estimated in the regenerating granulation tissue using Western blot.FindingsDressing of wounds with 5% hesperidin hydrogel led to a higher and early wound contraction and significantly reduced mean wound healing time by 5.7 days than 5% naringin or combination of hesperidin and naringin hydrogels in the ratio of 1:1, 2:1, or 1:2. Hesperidin hydrogel wound dressing caused higher collagen and DNA syntheses than other groups at all times after injury. Glutathione concentration and superoxide dismutase activity increased followed by a decline in lipid peroxidation in regenerating wounds after hesperidin/naringin hydrogel application and a maximum effect was observed for hesperidin alone. The hesperidin/naringin hydrogel suppressed NF-κB and COX-2 expression on days 6 and 12.ConclusionsApplication of 5% hesperidin hydrogel was more effective than 5% naringin or combination of hesperidin and naringin gels (1:1, 2:1 or 1:2) indicated by a greater wound contraction, reduced mean wound healing time, elevated collagen and DNA syntheses, rise in glutathione concentration, and superoxide dismutase activity followed by reduced lipid peroxidation, and NF-κB, and COX-2 expression.     

Healing of full-thickness wounds treated with lyophilized cultured keratinocyte cell lysate in genetically diabetic mice

The effect of a lyophilized cell lysate prepared from cultured human keratinocytes on the healing of full-thickness wounds was evaluated in an impaired healing model. Full-thickness wounds (8 mm in diameter) were made on the dorsal areas of female genetically diabetic mice C57 BL/KsJ (db/db) and their normal (db/+) littermates. Wounds were covered with an occlusive polyurethane film dressing and were treated for 5 days either with the lyophilized cell lysate from cultured human keratinocytes prepared in phosphate-buffered saline solution or with phosphate-buffered saline solution. In normal (db/+) mice, all wounds were closed 16 days after wounding, and more than 90% of the wound closure was due to wound contraction. Wound contraction accounted for a similar extent of wound closure in both lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. In contrast, in the diabetic (db/db) mice, after histologic examination of the wounds 32 days after wounding, four of ten lyophilized cell lysate-treated wounds and four of seven phosphate-buffered saline-treated wounds were found to be closed. Moreover, applications of lyophilized cell lysate from cultured human keratinocytes to full-thickness wounds in diabetic db/db mice significantly decreased the contribution of contraction to wound closure. Day 32 after wounding, contraction contribution to wound closure amounted to 57.7%+/- 4.7% and 80.4%+/- 3.2% (mean +/- standard error of the mean, p < 0.005) of the initial wound areas, respectively, for lyophilized cell lysate-treated and phosphate-buffered saline solution-treated wounds. At this time of wound healing, the thickness of the dermis was increased 1.7-fold by the keratinocyte cell lysate treatment, but neither epithelial migration from the wound edges nor the thickness of the regenerated epithelium were significantly affected. In conclusion, in diabetic (db/db) mice the application of lyophilized cell lysate from cultured human keratinocytes influenced the healing of the dermis and wound contraction, but had no effect on reepithelialization.     

Peroxide‐based oxygen generating topical wound dressing for enhancing healing of dermal wounds

Oxygen generating biomaterials represent a new trend in regenerative medicine that aims to generate and supply oxygen at the site of requirement, to support tissue healing and regeneration. To enhance the healing of dermal wounds, we have developed a highly portable, in situ oxygen generating wound dressings that uses sodium percarbonate (SPO) and calcium peroxide (CPO) as chemical oxygen sources. The dressing continuously generated oxygen for more than 3 days, after which it was replaced. In the in vivo testing on porcine full‐thickness porcine wound model, the SPO/CPO dressing showed enhanced wound healing during the 8 week study period. Quantitative measurements of wound healing related parameters, such as wound closure, reepithelialization, epidermal thickness and collagen content of dermis showed that supplying oxygen topically using the SPO/CPO dressing significantly accelerated the wound healing. An increase in neovascularization, as determined using Von Willebrand factor (vWF) and CD31 staining, was also observed in the presence of SPO/CPO dressing. This novel design for a wound dressing that contains oxygen generating biomaterials (SPO/CPO) for supplying topical oxygen, may find utility in treating various types of acute to chronic wounds.     

Exogenous calreticulin improves diabetic wound healing

A serious consequence of diabetes mellitus is impaired wound healing, which largely resists treatment. We previously reported that topical application of calreticulin (CRT), an endoplasmic reticulum chaperone protein, markedly enhanced the rate and quality of wound healing in an experimental porcine model of cutaneous repair. Consistent with these in vivo effects, in vitro CRT induced the migration and proliferation of normal human cells critical to the wound healing process. These functions are particularly deficient in poor healing diabetic wounds. Using a genetically engineered diabetic mouse (db/db) in a full‐thickness excisional wound healing model, we now show that topical application of CRT induces a statistically significant decrease in the time to complete wound closure compared with untreated wounds by 5.6 days (17.6 vs. 23.2). Quantitative analysis of the wounds shows that CRT increases the rate of reepithelialization at days 7 and 10 and increases the amount of granulation tissue at day 7 persisting to day 14. Furthermore, CRT treatment induces the regrowth of pigmented hair follicles observed on day 28. In vitro, fibroblasts isolated from diabetic compared with wild‐type mouse skin and human fibroblasts cultured under hyperglycemic compared with normal glucose conditions proliferate and strongly migrate in response to CRT compared with untreated controls. The in vitro effects of CRT on these functions are consistent with CRT's potent effects on wound healing in the diabetic mouse. These studies implicate CRT as a potential powerful topical therapeutic agent for the treatment of diabetic and other chronic wounds.     

A novel recombinant human collagen hydrogel as minced split-thickness skin graft overlay to promote full-thickness skin defect reconstruction

To overcome limited donor-site availability in patients with extensive burns, split-thickness skin grafts (STSGs) are sometimes minced into micrografts (MGs) to improve the expansion ratio of the grafts, but this may reduce wound healing. We aimed to produce a novel hydrogel as an overlay of minced STSGs to improve wound healing. The new hydrogel was produced using recombinant human collagen type III powder as a raw material. Morphological and physical characteristics (degradation and swelling rate), cytotoxicity, and cell viability of the hydrogel were evaluated in vitro. A full-thickness in vivo skin defect model was constructed with male Sprague-Dawley rats. The animals were randomly assigned to experimental and control groups in which the new hydrogel and Vaseline gauze, respectively, were overlaid on minced STSGs to repair and regenerate skin wound. The healing rates and recovery status were compared between the two groups. The hydrogels exhibited good water retention properties and a suitable degradation rate, which can promote the proliferation and migration of wound healing-related cells in vitro. Further, using the hydrogel as an overlay accelerated wound closure and angiogenesis, increased dermal tissue and basement membrane formation, enhanced collagen synthesis and wound healing-related growth factor expression, while reducing scar formation compared to the Vaseline gauze group. In conclusion, the novel, low-cost recombinant human collagen hydrogel can accelerate wound closure and improve wound healing when used as an overlay of minced STSGs. The new hydrogel could become a new treatment option for traumatic skin wounds caused by burns or injuries.     

Full‐thickness splinted skin wound healing models in db/db and heterozygous mice: Implications for wound healing impairment

The excisional dorsal full‐thickness skin wound model with or without splinting is widely utilized in wound healing studies using diabetic or normal mice. However, the effects of splinting on dermal wound healing have not been fully characterized, and there are limited data on the direct comparison of wound parameters in the splinted model between diabetic and normal mice. We compared full‐thickness excisional dermal wound healing in db/db and heterozygous mice by investigating the effects of splinting, semi‐occlusive dressing, and poly(ethylene glycol) treatment. Two 8‐mm full‐thickness wounds were made with or without splinting in db/db and heterozygous mice. Body weights, splint maintenance, wound contraction, wound closure, and histopathological parameters including reepithelialization, wound bed collagen deposition, and inflammation were compared between groups. Our results show that silicone splint application effectively reduced wound contraction in heterozygous and db/db mice. Splinted wounds, as opposed to nonsplinted wounds, exhibited no significant differences in wound closure between heterozygous and db/db mice. Finally, polyethylene glycol and the noncontact dressing had no significant effect on wound healing in heterozygous or db/db mice. We believe these findings will help investigators in selection of the appropriate wound model and data interpretation with fully defined parameters.     

Acceleration of wound contraction and healing with a photocrosslinkable chitosan hydrogel

Application of ultraviolet light irradiation to a photocrosslinkable chitosan aqueous solution resulted in an insoluble, flexible hydrogel like soft rubber within 60 seconds. In order to evaluate its accelerating effect on wound healing, full-thickness skin incisions were made on the backs of mice and subsequently a photocrosslinkable chitosan aqueous solution was added into the wound and irradiated with UV light for 90 seconds. Application of the chitosan hydrogel significantly induced wound contraction and accelerated wound closure and healing compared with the untreated controls. Histological examination also showed an advanced contraction rate on the first 2 days and tissue fill rate on days 2 to 4 in the chitosan hydrogel-treated wounds. Furthermore, in cell culture studies, chitosan hydrogel culture medium supplemented with 5% fetal-bovine serum was found to be chemoattractant for human dermal fibroblasts in an invasion chamber assay using filters coated with Matrigel and in a cell migration assay. Due to its ability to accelerate wound contraction and healing, chitosan hydrogel may become accepted as an occlusive dressing for wound management.     

Stimulation of steroid-suppressed cutaneous healing by repeated topical application of IGF-I: different mechanisms of action based upon the mode of IGF-I delivery

BACKGROUND: Insulin-like growth factor-I (IGF-I) is accepted as a potent stimulus of wound healing when applied in combination with its binding proteins. However, there is only one study published that has investigated the effect of repeated topical application of unbound IGF-I on ischemic wound healing. The aim of this study was to show the effect of daily topical IGF-I therapy on cutaneous ulcer healing in a steroid-suppressed wound model. MATERIALS AND METHODS: Full-thickness wounds were created on the back of 40 male Sprague-Dawley rats. Before surgery, animals received depot-steroids subcutaneously. Wounds were treated daily with either a standard hydrogel dressing (control), topical IGF-I dissolved in 0.2% methylcellulose gel (IGF-I gel), or a hydrogel dressing containing IGF-I (IGF-I dressing). After 7 days of treatment, wounds were excised and measured by photoplanimetry. SMA- and PCNA-expression as well as the formation of granulation tissue were assessed in tissue sections. Results are given as median(min-max). Differences between groups were calculated by the Mann-Whitney U test. RESULTS: Subcutaneous injection of depot-steroids induced a significant delay in healing, as shown by an enlarged wound size [44(33-65) versus 25(20-35)] mm(2); P = 0.001). In steroid-treated rats, both IGF-I gel and IGF-I dressing enhanced excisional healing, as shown by a significant reduction in wound size (P = 0.0001), with IGF-I released from the dressing being even more effective than IGF-I gel (P = 0.03). However, in these animals only IGF-I released from the hydrogel dressing stimulated SMA- (P = 0.03) as well as PCNA-expression (P = 0.001) and increased granulation tissue formation (P = 0.018). CONCLUSIONS: Our data indicate that a repeated application of topical IGF-I enhances cutaneous ulcer healing. In addition, only the controlled release of IGF-I from the hydrogel dressing is capable of reversing the steroid-induced delay of healing, suggesting different mechanisms of action with respect to the mode of IGF-I delivery.     

Combination of ciclopirox olamine and sphingosine‐1‐phosphate as granulation enhancer in diabetic wounds

Granulation tissue formation requires a robust angiogenic response. As granulation tissue develops, collagen fibers are deposited and compacted. Forces generated in the wake of this process drive wound contraction to reduce the wound area. In diabetics, both angiogenesis and wound contraction are diminished leading to impaired wound healing. To emulate this pathology and to address it pharmacologically, we developed a wound healing model in the diabetic Zucker fatty rat and tested a topical proangiogenic strategy combining antifungal agent ciclopirox olamine (CPX) and lysophospholipid sphingosine‐1‐phosphate (S1P) to promote diabetic wound closure. In vitro, we demonstrated that CPX + S1P up‐regulates a crucial driver of angiogenesis, hypoxia‐inducible factor‐1, in endothelial cells. Injection of CPX + S1P into subcutaneously implanted sponges in experimental rats showed, in an additive manner, a fivefold increased endothelial infiltration and lectin‐perfused vessel length. We developed a splinted diabetic rodent model to achieve low wound contraction rates that are characteristic for the healing mode of diabetic ulcers in humans. We discovered specific dorsal sites that allowed for incremental full‐thickness excisional wound depths from 1 mm (superficial) to 3 mm (deep). This enabled us to bring down wound contraction from 51% in superficial wounds to 8% in deep wounds. While the effects of topical gel treatment of CPX + S1P were masked by the rodent‐characteristic dominant contraction in superficial wounds, they became clearly evident in deep diabetic wounds. Here, a fivefold increase of functional large vessels resulted in accelerated granulation tissue formulation, accompanied by a 40% increase of compacted thick collagen fibers. This was associated with substantially reduced matrix metalloproteinase‐3 and ‐13 expression. These findings translated into a fivefold increase in granulation‐driven contraction, promoting diabetic wound closure. With CPX and S1P analogues already in clinical use, their combination presents itself as an attractive proangiogenic treatment to be repurposed for diabetic wound healing.     

Enhanced healing of mitomycin C‐treated healing‐impaired wounds in rats with hydrosheets composed of chitin/chitosan,fucoidan, and alginate as wound dressings

To create a moist environment for rapid wound healing, a hydrosheet composed of alginate, chitin/chitosan, and fucoidan (ACF‐HS) has been developed as a functional wound dressing. The aim of this study was to evaluate the accelerating effect of ACF‐HS on wound healing for rat mitomycin C‐treated healing‐impaired wounds. Full‐thickness skin defects were made on the back of rats and mitomycin C was applied onto the wound for 10 minutes to prepare a healing‐impaired wound. After thoroughly washing out the mitomycin C, ACF‐HS was applied to the healing‐impaired wounds. The rats were later euthanized and histological sections of the wounds were prepared. The histological examinations showed significantly advanced granulation tissue and capillary formations in the healing‐impaired wounds treated with ACF‐HS on days 7 and 14, in comparison with that in alginate fiber (Kaltostat^®), hydrogel wound dressing (DuoACTIVE^®), and nontreatment (negative control). Furthermore, in cell culture studies, ACF‐HS‐absorbed serum and fibroblast growth factor‐2 was found to be proliferative for fibroblasts and endothelial cells, respectively, and ACF‐HS‐absorbed serum was found to be chemoattractive for fibroblasts. However, our results may not be strictly comparable with general healing‐impaired wound models in humans because of the cell damage by mitomycin C. In addition, more biocompatibility studies of fucoidan are essential due to the possibility of renal toxicity.     

Wound‐healing effect of adipose stem cell‐derived extracellular matrix sheet on full‐thickness skin defect rat model: Histological and immunohistochemical study

The potential use of extracellular matrix (ECM) as a source of wound dressing material has recently received much attention. The ECM is an intricate network of various combinations of elastin, collagens, laminin, fibronectin, and proteoglycans that play a key role in stimulating cell proliferation and differentiation. We evaluated the efficacy of an ECM sheet derived from human adipose tissue as a wound dressing material to enhance healing. We prepared a novel porous ECM sheet dressing scaffold from human adipose tissue. in vitro analysis of the ECM sheets showed efficient decellularisation; absence of immunostimulatory components; and the presence of a wide number of angiogenic and bioactive factors, including collagen, elastin, and proteoglycans. To evaluate in vivo efficacy, full‐thickness excisional wounds were created on the dorsal skin of a rat, and the ECM sheets; secondary healing foam wound dressing, Healoderm; or a conventional dressing were applied to each wound site. Photographs were taken every other day, and the degree of reepithelialisation of the wounds was determined. Application of an ECM sheet dressing enhanced the macroscopic wound‐healing rate on days 4, 7, and 10 compared with that in the control group. Microscopic analysis indicated that the reepithelialisation rate of the wound was higher in the ECM group compared with that in the control group; the reepithelialisation rate was better than that of the secondary healing foam wound dressing. Moreover, a denser and more organised granulation tissue was formed in the ECM sheet group compared with that in the secondary healing foam wound dressing and control groups. The ECM sheet also showed the highest microvessel density compared with the secondary healing foam wound dressing and control groups. Based on these data, we suggest that a bioactive ECM sheet dressing derived from human adipose can provide therapeutic proteins for wound healing.     

A parallel open-label trial to evaluate microbial cellulose wound dressing in the treatment of diabetic foot ulcers

The purpose of this study was to compare the rate of wound healing in diabetic foot ulcers (DFU) using either a microbial cellulose (MC) wound dressing or Xeroform? Petrolatum gauze. In a parallel, open‐label trial in which the primary outcome was the rate of wound healing and the time to wound closure, 15 ulcers in type II diabetic patients received an MC dressing. Wounds in 19 control patients with type II diabetes were treated with a Xeroform gauze dressing. All wounds were non infected, Wagner stage II or III and received standard care including debridement, non weight bearing limb support and weekly wound evaluation. The mean time to heal in the MC (±SE) treated group was 32 days ± 2·5 and for controls it was 48 days ± 4·7 (P < 0·01). The rate of weekly wound closure (mean ± SE) was 1·7 times faster in the MC‐treated group (cellulose treated, ?5·04% per week ± 0·38 versus control, ?2·93% per week ± 0·19), (P < 0·001). Among covariants tested by univariate regression, only the original wound area correlated with the time to wound closure (P < 0·001). In conclusion, with the provision of current standards of care, the application of an MC dressing to a diabetic ulcer may enhance the rate of wound healing and shorten the time course of epithelisation.     

145Biological Effects of Calreticulin on Wound Repair

Calreticulin (CRT) is a major classic Ca‐binding chaperone protein of the endoplasmic reticulum. Recently, CRT has been recognized to have widespread extracellular effects as well. In the current study we show that CRT increases both epithelial migration and granulation tissue formation in models of porcine and murine wound repair. Partial thickness wounds were created on the paravertebral area of pigs (n = 4) and 0.1% and 0.5% CRT, and PDGF (positive control) applied for 4 consecutive days. In wounds harvested at 5 days, CRT induced a 28 and 22% greater extent of reepithelialization than PDGF and Tris/Ca buffer control, respectively (% healed = 56/CRT; 40.5/PDGF; 44/control). In addition, CRT stimulated earlier granulation tissue formation in a dose‐dependent manner (cumulative dermal depth, microns: 1615/CRT; 1250/PDGF; 1325/control). A similar granulation tissue inducing effect of CRT was also observed in a steroid‐impaired pig model. As a diabetic model of wound repair, two 5 mm circular full‐thickness wounds were created on the dorsum of db/db mice; the wounds were splinted open with silicone rings and covered with occlusive dressing (n = 24). After 5 days of treatment with 0.1, 0.5, and 5% CRT, a dose‐dependent 8‐, 4.5‐, and 2‐fold increase in granulation tissue formation was observed (p < 0.05). However, there was no apparent effect on wound closure. Tissue sections showed a highly cellular dermis in the CRT treated wounds. In addition, CRT (50 pg/ml) stimulated wound closure in a scratch plate assay using fibroblasts by 45%, in 48 hrs, compared to 2% for the control. Therefore, CRT may be a novel agent for wound healing by acting as a chemoattractant for cells involved in wound remodeling and in epithelial migration. Suppported by Calretex, LLC. NJ, USA (LIG) and the Alumni Fund, Alumni Association Downstate College of Medicine (MJC).     

Local release of pioglitazone (a peroxisome proliferator‐activated receptor γ agonist) accelerates proliferation and remodeling phases of wound healing

Peroxisome proliferator‐activated receptor γ (PPARγ) is a member of the nuclear receptor superfamily known for its anti‐inflammatory and macrophage differentiation effects, as well as its ability to promote fat cell differentiation and reduce insulin resistance. Pioglitazone (Pio) is a PPARγ agonist used clinically as an anti‐diabetic agent for improving insulin sensitivity in patients with diabetes. The objective of this study was to develop a drug delivery system (DDS) for the local release of Pio to promote wound healing. Pio of low aqueous solubility was water‐solubilized by micelles formed from gelatin grafted with L‐lactic acid oligomers, and incorporated into a biodegradable gelatin hydrogel. An 8‐mm punch biopsy tool was used to prepare two skin wounds on either side of the midline of 8‐week‐old mice. Wounds were treated by the hydrogels with (Pio‐hydrogel group) or without (control group) Pio, and the wound area were observed 1, 4, 7, and 14 days after treatment. In addition, a protein assay and immunohistological stain were performed to determine the effects of the Pio‐hydrogel on inflammation and macrophage differentiation. The Pio‐hydrogels promote wound healing. Moreover, Western blotting analysis demonstrated that treatment with Pio‐hydrogels resulted in decreased levels of the cytokines MIP‐2 and TGF‐β, and increased levels of glucose‐regulating adiponectin. It is concluded that Pio‐incorporated hydrogels promote the proliferation and remodeling phases of wound healing, and may prove to be effective as wound dressings.     

The wound‐healing effects of a next‐generation anti‐biofilm silver Hydrofiber wound dressing on deep partial‐thickness wounds using a porcine model

Topical antimicrobials are widely used to control wound bioburden and facilitate wound healing; however, the fine balance between antimicrobial efficacy and non‐toxicity must be achieved. This study evaluated whether an anti‐biofilm silver‐containing wound dressing interfered with the normal healing process in non‐contaminated deep partial thickness wounds. In an in‐vivo porcine wound model using 2 pigs, 96 wounds were randomly assigned to 1 of 3 dressing groups: anti‐biofilm silver Hydrofiber dressing (test), silver Hydrofiber dressing (control), or polyurethane film dressing (control). Wounds were investigated for 8 days, and wound biopsies (n = 4) were taken from each dressing group, per animal, on days 2, 4, 6, and 8 after wounding and evaluated using light microscopy. No statistically significant differences were observed in the rate of reepithelialisation, white blood cell infiltration, angiogenesis, or granulation tissue formation following application of the anti‐biofilm silver Hydrofiber dressing versus the 2 control dressings. Overall, epithelial thickness was similar between groups. Some differences in infiltration of specific cell types were observed between groups. There were no signs of tissue necrosis, fibrosis, or fatty infiltration in any group. An anti‐biofilm silver Hydrofiber wound dressing did not cause any notable interference with normal healing processes.     

Outcomes of allogenic acellular matrix therapy in treatment of diabetic foot wounds: an initial experience

The purpose of this study was to evaluate outcomes of persons with UT grade 2A neuropathic diabetic foot wounds treated with an acellular matrix. Data were abstracted for 17 consecutive patients with diabetes--76.5% males, aged 61.5 +/- 8.5 years with a mean glycated haemoglobin of 9.2 +/- 2.2% presenting for care at a large, multidisciplinary wound care centre. All patients received surgical debridement for their diabetic foot wounds and were placed on therapy consisting of a single application of an acellular matrix graft (GraftJacket; Wright Medical Technologies, Arlington, TN, USA) with dressing changes taking place weekly. Outcomes evaluated included time to complete wound closure and proportion of patients achieving wound closure in 20 weeks. Acellular matrix therapy was used as initial therapy and was sutured or stapled in place under a silicone-based non adherent dressing. Therapy was then followed by a moisture-retentive dressing until complete epithelialisation. In total, 82.4% of wounds measuring a mean 4.6 +/- 3.2 cm(2) healed in the 20-week evaluation period. For those that healed in this period, healing took place in a mean 8.9 +/- 2.7 weeks. We conclude that a regimen consisting of moist wound healing using an acellular matrix dressing may be a useful adjunct to appropriate diabetic foot ulcer care for deep, non-infected, non-ischaemic wounds. We await the completion of further trials in this area to confirm or refute this initial assessment.     

A liposome hydrogel with polyvinyl-pyrrolidone iodine in the local treatment of partial-thickness burn wounds

Local treatment of burn injuries with conventional anti-infective preparations does not provide the moist environment that promotes fast wound healing. In a randomized controlled trial the effects of liposome polyvinyl-pyrrolidone-iodine (PVP-I) hydrogel, a novel formulation of PVP-I in a liposome hydrogel with high water-binding capacity, were investigated in 43 patients with partial-thickness burn wounds in an intraindividual comparison with a conventional silver-sulfadiazine cream. Treatment with liposome PVP-I hydrogel resulted in significantly faster complete healing of the burn wounds compared with silver-sulfadiazine cream (9.9 +/- 4.5 days versus 11.3 +/- 4.9; P < 0.015). The cosmetic result (smoothness, elasticity, appearance) was rated as excellent for 37.0% of study wounds with liposome PVP-I hydrogel compared with 13.0% of wounds treated with silver-sulfadiazine cream. Local tolerability was good; handling and change of dressing were rated as easy. Local treatment with liposome PVP-I hydrogel thus provides fast wound healing with a favorable cosmetic result.     

Novel fabrication of antibiotic containing multifunctional silk fibroin injectable hydrogel dressing to enhance bactericidal action and wound healing efficiency on burn wound: In vitro and in vivo evaluations

The development of biologically active multifunctional hydrogel wound dressings can assist effectively to wound regeneration and also has influenced multiple functions on wound injury. Herein, we designed a carbon‐based composited injectable silk fibroin hydrogel as multifunctional wound dressing to provide effective anti‐bacterial, cell compatibility and in vivo wound closure actions. Importantly, the fabricated injectable hydrogel exhibit sustained drug delivery properties, anti‐oxidant and self‐healing abilities, which confirm that composition of hydrogel is highly beneficial to tissue adhesions and burn wound regeneration ability. Frequently, designed injectable hydrogel can be injected into deep and irregular burn wound sites and would provide rapid self‐healing and protection from infection environment with thoroughly filled wound area. Meanwhile, incorporated carbon nanofillers improve injectable hydrogel strength and also offer high fluid uptake to hydrogel when applied on the wound sites. In vitro MTT cytotoxicity assay on human fibroblast cell lines establish outstanding cytocompatibility of the injectable hydrogel and also have capability to support cell growth and proliferations. In vivo burn wound animal model results demonstrate that the hydrogel dressings predominantly influenced enhanced wound contraction and also promoted greater collagen deposition, granulation tissue thickness and vascularization. This investigation''s outcome could open a new pathway to fabricate multifunctional biopolymeric hydrogel for quicker burn wound therapy and effectively prevents microenvironment bacterial infections.