Rate Of Reepithelialization Research Articles

R-Ras regulates vascular permeability, but not overall healing in skin wounds.

Wounds close by keratinocytes migrating from the edge of the wound and re-epithelializing the epidermis. It has been proposed that the major stimuli for wound closure are blood-derived growth factors, chemokines and cytokines. The small GTPase R-Ras, a known integrin activator, also regulates vascular permeability during angiogenesis, and blood vessels lacking R-Ras leak plasma proteins constantly. We explored whether the access to blood-derived proteins influences skin wound healing in R-Ras knockout (KO) mice. In skin wounds, R-Ras expression was mostly restricted to the vasculature in the granulation tissue. Angiogenic blood vessels in the R-Ras KO mice were significantly more permeable than in wild-type (WT) controls. Although the distances between epidermal tongues, and the panniculus carnosus muscles, were significantly longer in R-Ras KO than WT controls before the granulation tissue formation took place, there were no differences in the wound closure or re-epithelialization rates or granulation tissue formation. These findings were also corroborated in a special splint excision wound model. Our study shows that although R-Ras does not influence the skin wound healing itself, the blood vessels lacking R-Ras are leaky and thus could facilitate the access of blood-derived proteins to the wound.

Effects of human adipose-derived mesenchymal stem cells and platelet-rich plasma on healing of wounds with full-thickness skin defects in mice

Effects of human adipose-derived mesenchymal stem cells and platelet-rich plasma on healing of wounds with full-thickness skin defects in mice

Novel Biodegradable Polymeric Microparticles Facilitate Scarless Wound Healing by Promoting Re-epithelialization and Inhibiting Fibrosis.

Despite decades of research, the goal of achieving scarless wound healing remains elusive. One of the approaches, treatment with polymeric microcarriers, was shown to promote tissue regeneration in various in vitro models of wound healing. The in vivo effects of such an approach are attributed to transferred cells with polymeric microparticles functioning merely as inert scaffolds. We aimed to establish a bioactive biopolymer carrier that would promote would healing and inhibit scar formation in the murine model of deep skin wounds. Here we characterize two candidate types of microparticles based on fibroin/gelatin or spidroin and show that both types increase re-epithelialization rate and inhibit scar formation during skin wound healing. Interestingly, the effects of these microparticles on inflammatory gene expression and cytokine production by macrophages, fibroblasts, and keratinocytes are distinct. Both types of microparticles, as well as their soluble derivatives, fibroin and spidroin, significantly reduced the expression of profibrotic factors Fgf2 and Ctgf in mouse embryonic fibroblasts. However, only fibroin/gelatin microparticles induced transient inflammatory gene expression and cytokine production leading to an influx of inflammatory Ly6C+ myeloid cells to the injection site. The ability of microparticle carriers of equal proregenerative potential to induce inflammatory response may allow their subsequent adaptation to treatment of wounds with different bioburden and fibrotic content.

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.

Evaluation of corneal epithelial wound healing after penetrating keratoplasty in patients receiving a new matrix therapy agent (regenerating agent).

Complete epithelial wound healing is a milestone in early postoperative care after penetrating keratoplasty. The re-epithelialization rate after penetrating keratoplasty was measured in patients receiving a new matrix therapy agent (regenerating agent, Cacicol®) that mimics heparan sulphates. This was a prospective, open-label, uncontrolled, single-centre observational study. A total of 33 consecutive patients (33 eyes) who underwent an 8.25-mm diameter penetrating keratoplasty were treated with regenerating agent eye drops: one drop in the operating theatre immediately after graft, then on alternate days. Patients were divided into those at low risk (13 patients) and high risk (20 patients) of delayed wound healing, and follow-up was performed by digital slit lamp with fluorescein-dye testing repeated daily at a fixed time. Dye area was measured using ImageJ freeware. The main endpoint was epithelial healing after regenerating agent therapy. The mean ± standard deviation time to complete healing for all patients was 2.7 ± 1.1 (median: 3, range: 1-6) days. This was obtained on Day 1 for 15% of patients, Day 2 for 33%, Day 3 for 88%, Day 4 for 94% and Day 6 for 100%. There was no significant difference between low- and high-risk patients. The area of epithelial defect decreased by a mean ± standard deviation of 75% ± 22% between Day 1 and Day 2, corresponding to a mean ± standard deviation wound-healing rate of 11.5 ± 6.5 mm2/D. There were no systemic or local side effects related to regenerating agent. These preliminary data suggest that regenerating agent could be a useful, non-invasive therapeutic approach in postoperative management of penetrating keratoplasty with the potential to accelerate re-epithelialization.

Meta-analysis and Systematic Review of Skin Graft Donor-site Dressings with Future Guidelines.

Background:Many types of split-thickness skin graft (STSG) donor-site dressings are available with little consensus from the literature on the optimal dressing type. The purpose of this systematic review was to analyze the most recent outcomes regarding moist and nonmoist dressings for STSG donor sites.Methods:A comprehensive systematic review was conducted across PubMed/MEDLINE, EMBASE, and Cochrane Library databases to search for comparative studies evaluating different STSG donor-site dressings in adult subjects published between 2008 and 2017. The quality of randomized controlled trials was assessed using the Jadad scale. Data were collected on donor-site pain, rate of epithelialization, infection rate, cosmetic appearance, and cost. Meta-analysis was performed for reported pain scores.Results:A total of 41 articles were included comparing 44 dressings. Selected studies included analysis of donor-site pain (36 of 41 articles), rate of epithelialization (38 of 41), infection rate (25 of 41), cosmetic appearance (20 of 41), and cost (10 of 41). Meta-analysis revealed moist dressings result in lower pain (pooled effect size = 1.44). A majority of articles (73%) reported better reepithelialization rates with moist dressings.Conclusion:The literature on STSG donor-site dressings has not yet identified an ideal dressing. Although moist dressings provide superior outcomes with regard to pain control and wound healing, there continues to be a lack of standardization. The increasing commercial availability and marketing of novel dressings necessitates the development of standardized research protocols to design better comparison studies and assess true efficacy.

Effects of quercetin on human oral keratinocytes during re-epithelialization: An in vitro study

BackgroundThe width of keratinized mucosa plays an important role in esthetic and functional outcomes of dental implants. Lack of keratinized mucosa may lead to poor oral hygiene and greater soft-tissue recession. This study aimed at assessing the potential of quercetin in promoting human oral keratinocyte (HOK) proliferation and re-epithelialization in vitro. Materials and MethodsHOK were detected in the absence or presence of test substances. The Cell Counting Kit-8 was used to assess cell viability and proliferation capacity. Re-epithelization was assessed using a keratinocyte monolayer scratch assay. Cell migration was monitored via Transwell chambers. Porphyromonas gingivalis lipopolysaccharide was used to stimulate keratinocytes for mimicking the inflammatory situation. mRNA expression of inflammatory cytokines (interleukin-1beta, IL-1β and tumor necrosis factor alpha, TNF-α), cell adhesion molecules (Integrin-α6, Integrin-β4), and growth factors (transforming growth factor beta 1,TGF-β1 and transforming growth factor beta 3, TGF-β3) were estimated using RT-qPCR. Protein contents of TGF-β1 and TGF-β3 were investigated by enzyme-linked immunosorbent assay. ResultsMultiplex analysis revealed that quercetin enhances HOK proliferation via an upregulation of adhesion molecules (Integrin-α6β4). Additionally, re-epithelialization rate was significantly greater in the presence of quercetin than in the control (P < 0.01). Furthermore, 20 μM of quercetin increases both mRNA and protein levels of TGF-β3 under basal and wound conditions without affecting TGF-β1 production. Expressions of pro-inflammatory cytokines were downregulated by quercetin treatment. ConclusionQuercetin promotes HOKs proliferation and oral re-epithelialization in vitro.

Use of a novel chitosan-based dressing on split-thickness skin graft donor sites: a pilot study.

Split-thickness skin graft (STSG) donor site dressings can play an integral role in reducing donor site morbidity. This study tested a novel, chitosan-based wound dressing, Opticell Ag, as an STSG donor site dressing for wounds <10% total body surface area (TBSA). Between January and December 2016, the chitosan-based dressing was placed on participating patients' donor sites immediately following graft harvest and covered with a transparent occlusive dressing. Pain was evaluated on postoperative day one, before dressing change between days 5-7, and before and after dressing removal between days 10-14 using the Visual Analog Scale (VAS). The extent of re-epithelialisation was determined between day 10-14 and at one month, and healing quality was also evaluated at one month post-operatively using the Vancouver Scar Scale (VSS). A total of 19 patients were recruited, of which 16 completed the study. Patients experienced mild-to-moderate pain in their donor sites when the chitosan-based dressing was used. Pain decreased significantly between postoperative day one and days 10-14, as well as between days 5-7 and 10-14. The mean percentage of re-epithelialisation on days 10-14 was 92% and by one month was 99%. The mean VSS at one month was 3.2±1.4. There were no statistically significant differences between patients' re-epithelialisation rates or VSS scores. There were unplanned dressing changes in four patients. No donor site infections or other adverse events were identified. The chitosan-based dressing tested in this study is safe, effective, and associated with reasonable pain control and acceptable healing quality. The results suggest that it is a promising STSG donor site dressing.

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.

Healing Effects of Dried and Acellular Human Amniotic Membrane and Mepitelas for Coverage of Skin Graft Donor Areas; A Randomized Clinical Trial.

Objective:To compare the healing effects of dried and acellular human amniotic membrane and Mepitel for coverage of split-thickness graft donor site (STGDS). Methods:Twenty patients who underwent STGDS regeneration surgery in identical anatomic regions were enrolled in this randomized controlled clinical trial conducted in Hazrate Fatemeh hospital (Iran). Patients were randomly assigned in 3 groups of wound dressing; group A by Mepitel, group B AmiCare (Dried amniotic membrane) and group C OcuReg-A (Acellular amniotic membrane). Re-epithelization rate (healing time), pain sensation, scar formation and infection rate were assessed till complete healing was achieved. Results: Our results showed no significant difference between Amicare, OcuReg-A and Mepitel in the features analyzed by us including: Re-epithelization rate (healing time) P value; 0.573, Pain sensation P value: day 4 th: 0.131, day8 th: 0.93 and day 12 th: 0.365, Scar formation P value>0.05and Infection rate. Conclusion: Our findings confirmed the safety and efficacy of AmiCare (dried amniotic membrane) and OcuReg-A (Acellular amniotic membrane) in treatment of split-thickness donor site in comparison with Mepitel as a standard wound dressing. Trial registration number: IRCT201511118177N12

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy-based enhancement of engraftment integration and remodeling.

The use of dermal substitutes to treat skin defects such as ulcers has shown promising results, suggesting a potential role for skin substitutes for treating acute and chronic wounds. One of the main drawbacks with the use of dermal substitutes is the length of time from engraftment to graft take, plus the risk of contamination and failure due to this prolonged integration. Therefore, the use of adjuvant energy-based therapeutic modalities to augment and accelerate the rate of biointegration by dermal substitute engraftments is a desirable outcome. The photobiomodulation (PBM) therapy modulates the repair process, by stimulating cellular proliferation and angiogenesis. Here, we evaluated the effect of PBM on a collagen-glycosaminoglycan flowable wound matrix (FWM) in an ex vivo human skin wound model. PBM resulted in accelerated rate of re-epithelialization and organization of matrix as seen by structural arrangement of collagen fibers, and a subsequent increased expression of alpha-smooth muscle actin (α-SMA) and vascular endothelial growth factor A (VEGF-A) leading to an overall improved healing process. The use of PBM promoted a beneficial effect on the rate of integration and healing of FWM. We therefore propose that the adjuvant use of PBM may have utility in enhancing engraftment and tissue repair and be of value in clinical practice.

Impact of Hyaluronic Acid-Containing Artificial Tear Products on Reepithelialization in an In Vivo Corneal Wound Model.

Purpose: To evaluate the effect of 6 commercially available hyaluronic acid (HA)-containing topical artificial tear products on corneal reepithelialization following injury, in an in vivo mouse model.Methods: Ninety-six C57Bl/6 mice (16 per treatment group; male to female ratio, 1:1 per group) were anesthetized. Epithelial debridement was performed on 1 cornea per animal, and the debrided eye was imaged. A 30 μL masked test solution containing 1 of 6 artificial tear products was instilled, immediately on debridement, and subsequently, every 2 h, for a total of 4 administrations. At 24 h post debridement, corneas were stained with fluorescein and imaged to calculate corneal healing rate (number of fluorescein-negative corneas).Results: All 6 artificial tear products used in this study permitted the initial process of corneal wound healing. However, the corneal reepithelialization rate after 24 h was higher with Hydroxypropyl guar (HPG)/HA (53.33%) compared with other HA-containing artificial tear products [HA1 (12.5%), HA2 (26.67%), HA3 (31.25%), HA4 (6.25%), and HA5 (43.75%)]. The average area and percentage area of reepithelialization after 24 h were also higher with HPG/HA compared with other treatment groups.Conclusions: Percentage of eyes with complete corneal reepithelialization 24 h post debridement was highest with HPG/HA compared with other HA-containing artificial tear products tested. The results of this study provide additional evidence on the potential benefits of HPG/HA in the management of dry eye and its role in the rapid restoration of a healthy ocular epithelium. However, further studies are required to confirm the effects on human corneal wounds.

Investigation of eucalyptus essence 1% and its mixture with licorice gel 10% on the infected third-degree burn wound in rat model

Many people have irreversible defects and to be death due to burn wounds every year. The current study was conducted to assess the effects of eucalyptus essence (EE) and its mixture with licorice in burn wound healing in rats. One hundred fifty rats were divided to five equal groups. Twenty-four hours after induction of third-degree burn wound, inoculation of 108 colony-forming units of Pseudomonas aeruginosa (PA 103) into the burnt area was performed in form of subcutaneous. Group 1 was given no treatment, and group 2 received gel base. Group 3 (positive control) was treated with silver sulfadiazine (SSD). Groups 4 and 5 used EE 1% and its mixture with licorice gel 10%, respectively. After 3, 7, 14, 21, and 28 days, the animals were euthanized and the wound healing parameters were evaluated through macroscopic and microscopic examinations. Microscopically, the rats treated with EE and mixture gel showed better wound healing than SSD (P < 0.05). This was demonstrated by the increase in re-epithelialization rate and neovascularization moreover as expected and also macroscopic observation was completed on day 21. No infection was found in treatment groups. Finally, skin strength in EE group was better than other groups (P < 0.05). Enhanced wound contraction, histological features, and reduced reepithelialization time suggest that 1% EE may have therapeutic benefits in burn wound healing.

The Significance of Repeat Cultures in the Treatment of Severe Fungal Keratitis

To identify fungal keratitis patients who are at risk of a poor outcome and may benefit from closer follow-up or more aggressive treatment. Secondary analysis of randomized clinical trial data. We compared the clinical outcomes of patients who had positive 6-day fungal cultures with those who did not, using backward stepwise regression with covariates for all baseline clinical characteristics. Patients presenting with a smear-positive filamentous fungal ulcer and visual acuity of 20/400 or worse, and who subsequently had a 6-day fungal culture performed at the Aravind Eye Care system (India), Lumbini Eye Hospital (Nepal), or Bharatpur Eye Hospital (Nepal). The primary outcome is rate of corneal perforation and/or the need for therapeutic penetrating keratoplasty. Secondary outcomes include 3-month best spectacle-corrected visual acuity (BSCVA), 3-month infiltrate and/or scar size, and rate of re-epithelialization. Patients who tested positive at their 6-day culture had twice the hazard of experiencing a corneal perforation or the need for therapeutic penetrating keratoplasty (P= .002) than those who tested negative, even after controlling for baseline ulcer characteristics. These patients also had on average 0.26 logMAR lines worse BSCVA at 3months (P= .001). Culture positivity at day 6 was not a statistically significant predictor of 3-month infiltrate/scar-size (-0.24mm1; P= .45) or time to re-epithelialization (hazard ratio= .81; P= .31). Here we identify a uniquely valuable clinical tool, day 6 culture results, for the treatment of severe fungal keratitis. Risk stratification based on repeat culture positivity is an objective way to assess response to medical therapy and identify patients who are at high risk of a poor clinical outcome. This establishes a new standard of care for severe fungal keratitis management.

Lack of effect of a topical regenerative agent on re-epithelialization rate of canine spontaneous chronic corneal epithelial defects: A randomized, double-masked, placebo-controlled study

Spontaneous chronic corneal epithelial defects (SCCEDs) are characteristic ulcers in dogs that are refractory to healing. The aim of the study was to evaluate the use of a topical regenerative agent to promote healing of SCCEDs. Nineteen dogs (20 eyes) were randomized to receive either regenerative agent (10 eyes) or placebo (10 eyes) every 48h following corneal debridement, which was repeated 1 week later if the SCCED had not yet healed. The mean±standard deviation time to re-epithelialization was 17.3±12.8 days for the group treated with a topical regenerative agent and 19.3±11.7 days for the group treated with a placebo; the cumulative healing rates were not statistically different (P>0.650). A positive association was found between the initial size of the ulcer and the time to re-epithelialization (r=0.555, P=0.011). Although well tolerated by dogs, there was no therapeutic advantage in using a topical regenerative agent for re-epithelialization of SCCEDs.

Effects of Lactobacillus rhamnosus (ATCC 7469) ointment on second-degree burn wound in Wistar rat

Introduction: Burn is among the traumas that impose great physical and psychological damages to the injured people. Scientists still are looking for new treatments and methods for burn management that lack the defects of previous ones. Recently, the potential of probiotic bacteria for the treatment of skin disease and problems has been investigated. Considering that the effects of probiotics are strain-dependent, the aim of current study was to evaluate the effects of Lactobacillus rhamnosus (ATCC 7469) on the process of burn wound healing. Materials and methods: After induction of second-degree burn wounds on the back of rats, they were randomly divided into experimental, vehicle control, and negative control groups. The experimental groups received a bacterial ointment for 1, 3, 7, and 14 days. The vehicle control groups received Eucerin for durations like the experimental groups. The negative control groups received no treatment in the same days. The evaluation of wound healing was conducted macroscopically by computing of the healing percent and microscopically by Hematoxylin and Eosin staining of the tissue samples of the wound area on different days. Results: The wound healing percent in the experimental group, compared with control groups, significantly increased, until the day 7 of the experiments. Moreover, the microscopic results indicate that the bacteria may have some anti-inflammatory effects. Also, the bacteria increased the rate of fibroblastic migration and re-epithelialization in the wound area.

Superiority of occipital donor sites for split-thickness skin grafting in dermatosurgery: Results of a prospective randomized controlled study.

Split-thickness skin grafts are commonly used in dermatosurgery. For occipital donor sites, retrospective studies have shown good results with respect to graft take and healing rates. Nevertheless, the majority of grafts in dermatosurgery are harvested from the thigh. To date, there has been no prospective randomized controlled study comparing occipital versus femoral donor sites. Following micrographically controlled R0 tumor resection, 108 patients were randomized prior to undergoing split-thickness skin grafting (donor site: occiput vs. thigh). Follow-up examinations were carried out on day 3, 5, 7, and 14, as well as one month and three months after surgery. Documented data included graft take rates, re-epithelialization rates at the donor site, pain, cosmetic outcome, Vancouver Scar Scale (VSS), and complications. Occipital donor sites showed significantly faster reepithelization, less pain, fewer complications, a better cosmetic outcome, and better results on the VSS. With regard to graft take rates, grafts harvested from the occiput were significantly superior on days 3 and 5. This is the first randomized controlled trial showing a significant superiority of occipital compared to femoral donor sites regarding re-epithelialization, pain, cosmetic outcome and the Vancouver Scar Scale.

Evaluation of the Role of Umbilical Cord Serum and Autologous Serum Therapy in Reepithelialization After Keratoplasty: A Randomized Controlled Clinical Trial.

To evaluate the role of umbilical cord serum (UCS) and autologous serum (AS) therapy in reepithelialization of corneal graft after keratoplasty in a randomized controlled trial. A total of 105 eyes with epithelial defect (ED) after keratoplasty (penetrating keratoplasty-67 and anterior lamellar keratoplasty-38) on the first postoperative day were included in the study. The eyes were randomized into three groups: UCS (n=35), AS (n=35), and artificial tears (AT) (n=35). All patients received standard postoperative medical therapy. The primary outcome measure was time to epithelialization, and secondary outcome measures were best-corrected visual acuity and graft clarity. The ED healed completely in 103 eyes. The mean time for complete reepithelialization was 2.5±2.1, 3.1±2.2, and 4.5±1.4 days in UCS, AS, and AT groups, respectively. The mean percentage decrease in the size of the ED was significantly better in the UCS and AS groups as compared with the AT group (P=0.001). The rate of reepithelialization was comparable between the AS and UCS groups (P=0.3). On bivariate analysis, significant correlation was found between the mean size of postoperative ED, grade of the donor cornea (P=0.001), and the presence of preoperative ED (P=0.001). No complications were associated with the use of serum therapy. Most of the cases of postkeratoplasty corneal ED can be managed with AT only. The serum therapy (AS/UCS) helps in the faster reepithelialization of postkeratoplasty ED as compared with AT and may be considered as a treatment option for early epithelial healing.

Wound Healing from Dermal Grafts Containing CD34+ Cells Is Comparable to Wound Healing with Split-Thickness Skin Micrografts

Epidermal stem cells present in the skin appendages of the dermis might be crucial in wound healing. In this study, the authors located these cells in the dermis and evaluated their contribution to full-thickness wound healing in a porcine model. Four sequentially deeper 0.35-mm-thick skin grafts were harvested from the same donor site going down to 1.4 mm in depth (layers 1 through 4). The layers were minced to 0.8 × 0.8 × 0.35-mm micrografts and transplanted (1:2) onto full-thickness porcine wounds. Healing was monitored up to 28 days and biopsy specimens were collected on days 6 and 10. Multiple wound healing parameters were used to assess the quality of healing. The authors' results showed that wounds transplanted with layer 2 (0.35 to 0.7 mm) and layer 3 (0.7 to 1.05 mm) micrografts demonstrated reepithelialization rates comparable to that of split-thickness skin graft (layer 1, 0.00 to 0.35 mm; split-thickness skin graft) at day 10. At day 28, dermal micrografts (layers 2 and 3) showed quality of healing comparable to that of split-thickness skin grafts (layer 1) in terms of wound contraction and scar elevation index. The amounts of epidermal stem cells [cluster of differentiation (CD) 34] and basal keratinocytes (KRT14) at each layer were quantified by immunohistochemistry. The analysis showed that layers 2 and 3 contained the most CD34 cells and layer 1 was the richest in KRT14 cells. The immunohistochemistry also indicated that, by day 6, CD34 cells had differentiated into KRT14 cells, which migrated from the grafts and contributed to the reepithelialization of the wound.

New polylactic acid/ cellulose acetate-based antimicrobial interactive single dose nanofibrous wound dressing mats

New single dose interactive extracellular matrix (ECM) mimicking nanofibrous wound dressings based on polylactic acid (PLA) and cellulose acetate (CA) were developed, characterized and investigated for wound treatment. The antimicrobial agent, thymoquinone (TQ) was selected and incorporated into the scaffolds for preventing common clinical infections, and to accelerate the rate of wound closure and re-epithelialization. The newly fabricated TQ-loaded PLA/CA wound dressings offered many advantages such as mimicking the ECM via the 3D nanofibrous structure, and promoted the cell proliferation due to the hydrophilicity and bioactivity of CA. The wound dressings also prevented the bacterial infection in the early stages due to presence of TQ, and maintained the minimum possible bacterial load in the wound area through the sustained release of the drug for 9days. In vivo assessment demonstrated that TQ-loaded PLA: CA (7:3) scaffolds significantly promoted the wound healing process by increasing re-epithelialization and controlling the formation of granulation tissue. The obtained results suggest that the developed TQ-loaded PLA/CA nanofibrous mats could be ideal for wound dressing applications.