Combined Amniotic Membrane and Self-Powered Electrical Stimulator Bioelectronic Dress Promotes Wound Healing

Human amniotic membranes (hAMs) are widely used as wound management biomaterials, especially as grafts for corneal reconstruction due to the structure of the extracellular matrix and excellent biological properties. However, their fragile nature and rapid degradation rate hinder widespread clinical use. In this work, we engineered a novel self-powered electronic dress (E-dress), combining the beneficial properties of an amniotic membrane and a flexible electrical electrode to enhance wound healing. The E-dress displayed a sustained discharge capacity, leading to increased epidermal growth factor (EGF) release from amniotic mesenchymal interstitial stem cells. Live/dead staining, CCK-8, and scratch-wound-closure assays were performed in vitro. Compared with amniotic membrane treatment alone, the E-dress promoted cell proliferation and migration of mouse fibroblast cells and lower cytotoxicity. In a mouse full-skin defect model, the E-dress achieved significantly accelerated wound closure. Histological analysis revealed that E-dress treatment promoted epithelialization and neovascularization in mouse skin. The E-dress exhibited a desirable flexibility that aligned with tissue organization and displayed maximum bioactivity within a short period to overcome rapid degradation, implying great potential for clinical applications.

Microvascular Fragment-Loaded Platelet-Rich Plasma Dressing Promotes Cutaneous Wound Healing

Objective: Chronic wounds represent a considerable burden for the affected patients and the health care system. To overcome this problem, effective treatment strategies are urgently required. In this study, we tested a novel approach by combining platelet-rich plasma (PRP) and microvascular fragments (MVF) to create a prevascularized gel dressing. Approach: MVF were enzymatically isolated from the epididymal fat pads of transgenic green fluorescent protein (GFP)+ C57BL/6J donor mice. Subsequently, 5,000 MVF were suspended in 10 μL murine PRP as carrier and transferred into full-thickness skin wounds within dorsal skinfold chambers of C57BL/6J wild-type mice (PRP+MVF). Wound healing in comparison to empty wounds (control) and wounds filled with PRP alone was repeatedly analyzed throughout 14 days by means of stereomicroscopy, histology, and immunohistochemistry. Results: Planimetric assessment of the wound size over time revealed a significantly accelerated and improved healing of PRP+MVF-treated wounds when compared with PRP-treated and empty control wounds. These wounds also exhibited a significantly higher density of blood and lymph vessels, which originated from the GFP+ MVF isolates and effectively promoted granulation tissue formation inside the skin defects. Innovation: This study is the first to combine PRP and MVF for the improvement of wound healing. Conclusion: The combination of PRP and MVF represents a promising approach for the future treatment of wounds that do not heal spontaneously due to poor wound-healing conditions.

Origin and development of primary animal epithelia

Epithelia are the first organized tissues that appear during development. In many animal embryos, early divisions give rise to a polarized monolayer, the primary epithelium, rather than a random aggregate of cells. Here, we review the mechanisms by which cells organize into primary epithelia in various developmental contexts. We discuss how cells acquire polarity while undergoing early divisions. We describe cases where oriented divisions constrain cell arrangement to monolayers including organization on top of yolk surfaces. We finally discuss how epithelia emerge in embryos from animals that branched early during evolution and provide examples of epithelia-like arrangements encountered in single-celled eukaryotes. Although divergent and context-dependent mechanisms give rise to primary epithelia, here we trace the unifying principles underlying their formation.

Comparison of the Effectiveness of a Novel Matrix-Modified Bovine Collagen Membrane With a Conventional Bovine Collagen Membrane for Oral Mucosal Defects: A Single-Center Study

Background Surgical procedures such as excision of a growth or lesion lead to soft tissue or oral mucosal defects. These defects require a proper surgical dressing to promote better wound healing and to avoid infection and scarring. A collagen membrane is one of the most commonly used surgical dressings because of its ease of adaptability to defects and its inherent ability to promote epithelialization and inhibition of pain through the indirect mechanism of preventing infection of the surgical site. Collagen also serves as a reservoir of regenerative factors. The regenerative potential increases as porosity decreases. The novel bovine-derived collagen membrane used in this current study has an average porosity of 20 microns which increases the availability of regenerative factors. Objective  The aim of this study was to compare the effectiveness between a novel matrix-modified bovine collagen membrane (SurgiColl) and a conventional bovine collagen membrane for promoting wound healing for oral mucosal or soft tissue defects. Materials and methods This clinical trial was conducted in the Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospital. The sample size of the study was 20, divided into two groups: novel bovine collagen (Surgicoll-Mesh) (Group 1) and conventional bovine collagen (Group 2) with 10 participants in each group. The randomization process was adopted. The parameters assessed were epithelialization, granulation, and wound contraction at the end of two weeks. All the parameters were assessed using a standardized visual assessment scale. Statistical analysis was done using IBM SPSS Statistics for Windows, Version 23.0 (Released 2015; IBM Corp., Armonk, New York, United States), and an independent sample t-test was done at 95% confidence interval. A p-value of less than 0.05 was considered statistically significant. Results The difference in epithelialization between the two groups was statistically significant with a p-value of 0.015 (<0.05). The difference in granulation tissue formation between the two groups was statistically significant with a p-value of 0.015 (<0.05). The difference in wound contraction at the end of two weeks between the two groups was also statistically significant with a p-value of 0.005 (<0.05). Group 1 showed superior results compared to Group 2 for all the outcomes assessed. Conclusion  The novel bovine-derived collagen membrane (SurgiColl-Mesh) was superior in its properties of wound healing for oral mucosal or soft tissue defects than the conventional bovine collagen membrane.

SMAD2/3 signaling regulates initiation of mouse Wolffian ducts and proximal differentiation in Müllerian ducts

Male and female reproductive tracts develop from anterior intermediate mesoderm with similar differentiation processes. The anterior intermediate mesoderm develops into the mesonephros, and the Wolffian duct initiates by epithelialization in the mesonephros. The Müllerian duct invaginates from the coelomic epithelium of the cranial mesonephros for ductal formation and is then regionalized into proximal to caudal female reproductive tracts. In this study, we focused on the epithelialization of the Wolffian duct, initiation of the Müllerian duct, and the regionalization step of the Müllerian ducts as a continuous process. By using intermediate mesodermal cells from mouse pluripotent stem cells, we identified that inhibition of SMAD2/3 signaling might be involved in the differentiation into mesenchymal cells, after which mesonephric cells might be then epithelialized during differentiation of the Wolffian duct. Aggregation of coelomic epithelial cells might be related to initiation of the Müllerian duct. Transcriptomic analysis predicted that consensus sequences of SMAD3/4 were enriched among highly expressed genes in the proximal Müllerian duct. SMAD2/3 signaling to regulate differentiation of the Wolffian duct was continuously activated in the proximal Müllerian duct and was involved in proximal and oviductal regionalization. Therefore, SMAD2/3 signaling may be finely tuned to regulate differentiation from initiation to regionalization steps.

Study the Effect of Calendula officinalis Extract Loaded on Zinc Oxide Nanoparticle Cream in Burn Wound Healing

The skin, the body's largest organ, acts as a protective barrier against pathogens and environmental damage. Skin burns can result from heat, chemicals, friction, or electricity. Nanoscience has recently been utilized to create ointments and creams for burns. Zinc oxide nanoparticles are crucial due to their antimicrobial and antioxidant properties. In this study, a cream containing nanoparticles was loaded with calendula extract, and its ability to promote tissue healing was investigated in Wistar rats with skin burns. The zinc oxide nanoparticles were chemically synthesized and loaded with calendula extract. The morphology and physicochemical properties of the nanoparticles were confirmed by SEM, ZETA size, XRD, and FTIR assays. The MTT technique was employed to assess the cream's impact on fibroblast growth. The antimicrobial activity of the nanoparticles was investigated against Pseudomonas using the MIC method. Real-time PCR was used to determine the expression of the Bax and Bcl-2 genes in aeruginosa. The results showed that zinc oxide nanoparticles at high concentrations increased the proliferation of the fibroblast cells. Histopathological studies showed granulation and epithelialization of the tissue without any hemorrhage or tissue infection during the first days of treatment with this cream. The animal models treated with the cream showed an increase in Bcl-2 gene expression and a decrease in Bax expression. We concluded that zinc oxide nanoparticles loaded with calendula extract have a practical effect in healing burn wounds due to their unique antibacterial properties of zinc oxide nanoparticles and their anti-inflammatory and wound-healing effects. The synergistic effect of these two substances significantly improved the healing process. This newly developed cream can be introduced as a successful and viable treatment option in burn wounds.

Novel extracellular matrix wound dressing shows increased epithelialization of full-thickness skin wounds in dogs

OBJECTIVE

To compare the differences in the healing of surgically created full-thickness wounds in dogs treated with a novel extracellular matrix (ECM) dressing as compared with a standard wound management protocol and to investigate the effect of antibiotics in these 2 populations.

ANIMALS

15 purpose-bred Beagles, 8 female spayed and 7 males neutered, operated on, and monitored between March 14, 2022, and April 18, 2022.

METHODS

Four 2 X 2-cm full-thickness skin wounds were created on the trunks of each dog. The right-sided wounds were treated with the novel ECM wound dressing, and the left-sided wounds served as the controls. Wound planimetry and qualitative wound scores were obtained at 12 time points. Wound biopsies for histopathologic assessment of wound repair and wound inflammation were obtained at 6 time points.

RESULTS

Wounds treated with ECM had higher percent epithelization at days 7, 9, 12, and 18 postoperatively (P < .001) and better histologic repair scores (P = .024) than wounds treated by the standard protocol. Subjective wound assessment scores of wounds treated with ECM did not differ from those treated by the standard protocol at any time point.

CLINICAL RELEVANCE

Wounds treated with the novel ECM dressing epithelialized more rapidly than wounds treated by a standard protocol.

Preclinical assessment of novel longer-duration wear negative pressure wound therapy dressing in a porcine model

While reticulated open cell foam (ROCF) is a well-established dressing for negative pressure wound therapy (NPWT), there is the known potential for granulation tissue ingrowth if left in place for longer than 72 h. This may cause wound bed disruption, bleeding, and pain upon dressing removal. In addition, any retained foam fragments may elicit an adverse tissue reaction. A novel, easy to use dressing designed to utilise the advantages of ROCF while addressing its challenges has recently been created. This 7 day study investigated the utility of a novel NPWT dressing under longer-duration wear circumstances while assessing the prevalence of tissue ingrowth and ease of dressing removal in full-thickness excisional wounds utilising a porcine model. Histopathology and morphometry evaluations indicated thicker granulation tissue with, depending on the parameters assessed, either comparable or better tissue quality for wounds treated with the novel dressing. Greater re-epithelialization levels were also evident compared with ROCF. Three-dimensional imaging analysis indicated faster wound fill with a corresponding decrease in wound area with the novel dressing. Furthermore, tissue ingrowth was limited to only ROCF-treated wounds, which was not unexpected in this longer-duration wear study. The force required to remove the novel dressing was considerably lower compared with ROCF, correlating to the tissue ingrowth results. Results of this study illustrate that the novel dressing provided more favourable wound healing results compared with traditional ROCF. In addition, reduction in the risk of tissue ingrowth and low dressing peel force may allow it to be used as a longer-wear dressing.

A morphogenetic wave in the chick embryo lateral mesoderm generates mesenchymal-epithelial transition through a 3D-rosette intermediate

Formation of epithelia through mesenchymal-epithelial transition (MET) is essential for embryonic development and for many physiological and pathological processes. This study investigates MET in vivo in the chick embryo lateral mesoderm, where a multilayered mesenchyme transforms into two parallel epithelial sheets that constitute the coelomic lining of the embryonic body cavity. Prior to MET initiation, mesenchymal cells exhibit non-polarized distribution of multiple polarity markers, albeit not aPKC. We identified an epithelializing wave that sweeps across the lateral mesoderm, the wavefront of which is characterized by the accumulation of basal fibronectin and a network of 3D rosettes composed of polarized, wedge-shaped cells surrounding a central focus of apical markers, now including aPKC. Initiation of the MET process is dependent on extracellular matrix-integrin signaling acting through focal adhesion kinase and talin, whereas progression through the rosette phase requires aPKC function. We present a stepwise model for MET, comprising polarization, 3D-rosette, and epithelialization stages.

[Experience in the use of plasma exposure with the use of NO-therapy in the treatment of chronic wounds of various etiologies]

Modern treatment of wounds of various etiologies is presented as a comprehensive approach, including correction of the general somatic condition and adequate local treatment in strict accordance with the stages of the wound process. In relation to the outpatient link, it is a local gentle management of wound defects with proper treatment of the wound surface and wound management under an adequate wound coating that meets various tasks at various stages of the inflammatory process. The inclusion in the therapy of chronic wounds of electro- and radio-frequency equipment with mandatory treatment with NO-streams has a positive effect on the regeneration processes. The inclusion in the therapy of chronic wounds of plasma torch treatment generated by electrosurgical high-frequency MEDSI devices followed by mandatory treatment with NO- flows by ALFANO device has a positive effect on the regeneration processes.

A Tissue Engineered Construct for Laryngeal Regeneration: A Proof-of-Concept Device Design Study

OBJECTIVES/HYPOTHESIS

Develop a patient-specific tissue engineered construct for laryngeal reconstruction following a partial laryngectomy.

STUDY DESIGN

Bench and animal research.

METHODS

A construct made from a porous polyethylene scaffold shaped in a canine-specific configuration and seeded with autologous canine adipose-derived stem cells in fibrin glue was implanted in a canine following a partial laryngectomy. After 1 year, the construct was first evaluated in vivo with high-speed imaging and acoustic-aerodynamic measures. It was then explanted and evaluated histologically.

RESULTS

The canine study at 1 year revealed the construct provided voicing (barking) with acoustic and aerodynamic measures within normal ranges. The canine was able to eat and breathe normally without long-term support. The construct was integrated with epithelialization of all areas except the medial portion of the vocal fold structure. No anti-infective agents were needed after the standard perioperative medications were completed.

CONCLUSION

This study provided a successful first step toward developing a patient-specific composite construct for patients undergoing partial laryngectomies.

LEVEL OF EVIDENCE

Not Applicable Laryngoscope, 2022.

Plant-based Natural Products for Wound Healing: A Critical Review

Wound healing is an intricate process consisting of four overlapping phases, namely hemostasis, inflammation, proliferation, and remodelling. Effective treatment of wounds depends upon the interaction of appropriate cell types, cell surface receptors, and the extracellular matrix with the therapeutic agents. Several approaches currently used for treating wounds, such as advanced wound dressing, growth factor therapy, stem cell therapy, and gene therapy, are not very effective and lead to impaired healing. Further, repeated use of antibiotics to treat open wounds leads to multi- drug resistance. Today there is considerable interest in plant-based drugs as they are believed to be safe, inexpensive, and more suitable for chronic wounds. For example, a large number of plant- based extracts and their bioactive compounds have been investigated for wound healing. In recent years the structural and mechanistic diversity of natural products have become central players in the search for newer therapeutic agents. In the present review, a thorough critical survey of the traditionally used plant-based drugs used worldwide for wound healing with special reference to the natural products/bioactive compounds isolated and screened is presented. It is hoped that this review will attract the attention of the research community involved in newer drug design and development for wound healing.

The lysosomal trafficking regulator is necessary for normal wound healing

Non-healing wounds are a major threat to public health throughout the United States. Tissue healing is complex multifactorial process that requires synchronicity of several cell types. Endolysosomal trafficking, which contributes to various cell functions from protein degradation to plasma membrane repair, is an understudied process in the context of wound healing. The lysosomal trafficking regulator protein (LYST) is an essential protein of the endolysosomal system through an indeterminate mechanism. In this study, we examine the impact of impaired LYST function both in vitro with primary LYST mutant fibroblasts as well as in vivo with an excisional wound model. The wound model shows that LYST mutant mice have impaired wound healing in the form of delayed epithelialization and collagen deposition, independent of macrophage infiltration and polarisation. We show that LYST mutation confers a deficit in MCP-1, IGF-1, and IGFBP-2 secretion in beige fibroblasts, which are critical factors in normal wound healing. Identifying the mechanism of LYST function is important for understanding normal wound biology, which may facilitate the development of strategies to address problem wound healing.

Mastoid obliteration and external auditory canal reconstruction with silicone block in canal wall down mastoidectomy

OBJECTIVE

To prevent cavity problems in canal wall down mastoidectomy, silicone block for mastoid obliteration was used.

METHODS

In this retrospective cohort study, 39 patients (21 males and 18 females) underwent canal wall down mastoidectomy and mastoid obliteration using silicone block. We evaluated the postoperative outcome, the time until epithelialization of the cavity, graft success rate, and the hearing outcome.

RESULTS

The time until complete epithelialization of the mastoid cavity was 35.5 ± 5.4 days. We had a graft success rate of 100% during the follow-ups. The postoperative evaluation revealed 36 dry ears (92.3%) patients without any cavity problems. However, one ear developed granulation tissue, and two ears had partially exposed silicone block, which required revision mastoidectomy. Regarding hearing outcomes, a complication such as deaf ear was not reported.

CONCLUSION

Silicone block is safe and suitable for mastoid obliteration and external auditory canal reconstruction in canal wall down mastoidectomy.

LEVEL OF EVIDENCE

4.

Bacterial Cellulose as a Potential Bio-Scaffold for Effective Re-Epithelialization Therapy

Currently, there are several therapeutic approaches available for wound injury management. However, a better understanding of the underlying mechanisms of how biomaterials affect cell behavior is needed to develop potential repair strategies. Bacterial cellulose (BC) is a bacteria-produced biopolymer with several advantageous qualities for skin tissue engineering. The aim here was to investigate BC-based scaffold on epithelial regeneration and wound healing by examining its effects on the expression of scavenger receptor-A (SR-A) and underlying macrophage behavior. Full-thickness skin wounds were generated on Sprague-Dawley rats and the healing of these wounds, with and without BC scaffolds, was examined over 14 days using Masson’s trichome staining. BC scaffolds displayed excellent in vitro biocompatibility, maintained the stemness function of cells and promoted keratinocyte differentiation of cells, which are vital in maintaining and restoring the injured epidermis. BC scaffolds also exhibited positive in vivo effects on the wound microenvironment, including improved skin extracellular matrix deposition and controlled excessive inflammation by reduction of SR-A expression. Furthermore, BC scaffold significantly enhanced epithelialization by stimulating the balance of M1/M2 macrophage re-programming for beneficial tissue repair relative to that of collagen material. These findings suggest that BC-based materials are promising products for skin injury repair.

The wound healing effect of local leukocyte platelet-rich plasma after total hip arthroplasty: A randomized controlled trial

Rapid wound closure is important after arthroplasty procedures to prevent postoperative complications. Platelets are rich in growth factors and leukocytes contribute to innate immunity. We hypothesized that topical leukocyte platelet-rich plasma (L-PRP) derived from the blood of patients would be beneficial to wound healing. In this randomized controlled trial, patients subjected to elective total hip arthroplasty (THA) were assigned by concealed allocation either L-PRP application onto the sutured fascia or no application (control) after the THA intervention. In addition, all patients received 1.5 g protein/kg, 5 g L-arginine, 500 mg vitamin C and 44 mg zinc daily over the 4-week postoperative period to obtain optimal nutrition. The primary endpoint was complete healing of the skin incision. The secondary endpoints were blood transfusions, length of hospital stay, pain and wound infections. Sixteen patients in the L-PRP group and 17 patients in the control group completed the trial. L-PRP treatment accelerated complete wound healing after 3 weeks (seven in the L-PRP group vs. zero in the control group, p = 0.003) and after 4 weeks (12 in the L-PRP group vs. six in the control group, p = 0.037). No postoperative superficial wound infections occurred within 4 weeks, and there were no significant differences in the other secondary outcomes. L-PRP generated in 10 sex-matched healthy volunteers revealed increased concentrations of platelets (5.8-fold) and leukocytes (2.3-fold) compared with those in whole blood. Furthermore, the concentration of keratinocyte mitogen epidermal growth factor in L-PRP (380 ± 130 pg/ml, mean ± SD) was higher (p < 0.001) than that in serum (130 ± 26 pg/ml). In conclusion, a single intraoperative local application of L-PRP promoted wound healing after THA, possibly mediated by EGF receptor agonists.

Effectiveness Of Reactive Oxygen Species In An Oil-Based Medication For Healing Burn Wounds: A Case Series

Oxygen is considered a key element in the complex tissue repair process. O3-Oil antiseptics are obtained from the chemical reaction between ozone and unsaturated fatty acids of vegetable oils. The purpose of this study was to assess the effectiveness of a commercially available O3-Oil in the management of recalcitrant burn wounds. This study involved 20 patients with mid-deep and deep burn wounds (average TBSA approximately 23%, range 7-35%). Patient average age was 47 years (range 26-74 years), 8 were male. The presence of exudate, pain and delayed re-epithelialization, absence of tissue necrosis and/or sepsis were the inclusion criteria for the topical use of O3-Oil. In each patient two clinically similar areas were identified and treated every 48 hours with O3-Oil (Group 1) and conventional medication (Group 2). All the patients had positive bacterial culture results before treatment. A quicker reduction of exudates and pain and a progressive and faster bacterial load reduction was observed in Group 1. Negative cultures were obtained after 4 days on average in Group 1 (range 1-7 days) and 8 days in Group 2 (range 5-11 days). The present study demonstrated that Novox® provides a significant antibacterial effect, while stimulating reparative processes. According to our experience, the use of gel or pad is useful for re-epithelializing lesions, while the impregnated gauzes, which tend to adhere to the wound, are better used on lesions with granulation tissue.

Cell intercalation driven by SMAD3 underlies secondary neural tube formation

Body axis elongation is a hallmark of the vertebrate embryo, involving the architectural remodeling of the tail bud. Although it is clear how neuromesodermal progenitors (NMPs) contribute to embryo elongation, the dynamic events that lead to de novo lumen formation and that culminate in the formation of a 3-dimensional, neural tube from NMPs, are poorly understood. Here, we used in vivo imaging of the chicken embryo to show that cell intercalation downstream of TGF-β/SMAD3 signaling is required for secondary neural tube formation. Our analysis describes the events in embryo elongation including lineage restriction, the epithelial-to-mesenchymal transition of NMPs, and the initiation of lumen formation. We show that the resolution of a single, centrally positioned lumen, which occurs through the intercalation of central cells, requires SMAD3/Yes-associated protein (YAP) activity. We anticipate that these findings will be relevant to understand caudal, skin-covered neural tube defects, among the most frequent birth defects detected in humans.

A non-canonical type 2 immune response coordinates tuberculous granuloma formation and epithelialization

The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.

Amnion and collagen-based blended hydrogel improves burn healing efficacy on a rat skin wound model in the presence of wound dressing biomembrane

BACKGROUND

A burn wound is one of the most frequent and devastating injuries for patients which requires extensive care. Early treatment of burn wounds improves healing significantly.

OBJECTIVE

This study was designed to investigate the efficacy of amnion and collagen-based hydrogels on cutaneous burn wound healing in rats with covering membrane.

METHODS

We prepared a novel cell free hydrogel comprising human amnion, rabbit collagen, carboxymethyl cellulose sodium salt, citric acid, methyl paraben, propyl paraben, glycerin and triethanol amine. The wound covering membrane was developed from rabbit collagen and prawn shell chitosan. Beside swelling ratio, water absorption, equilibrium water content, gel fraction and spreadability analysis, in vitro cytotoxicity and biocompatibility tests were performed for the formulated hydrogels. Following the skin irritation study, second-degree burns were created on the dorsal region of the rats and the gels were applied with/without covering membrane to study the wound contraction and re-epithelialization period.

RESULTS

The formulated hydrogels were observed non-cytotoxic and compatible with human blood cells. No erythema and edema were found in skin irritation assay confirming the safety and applicability. Hydrogel consisting in a combination of amnion and collagen demonstrated significantly rapid wound healing, driven by complete re-epithelialization (16.75 ± 0.96 days) and closure by wound contraction (72 ± 3.27%, P < 0.0000009) when wound dressing membrane was used, whereas this gel alone healed about 62.5 ± 4.43% (P < 0.00001) and required 18.75 ± 0.50 days to complete re-epithelialization. Additionally, the gel with covering membrane treated group had maximum average body weight, food and water intake.

CONCLUSION

The amnion and collagen-based blended gel offers alternative possibilities to treat skin wounds when covered with film, which could overcome the limitations associated with modern therapeutic products such as high costs, long manufacturing times, complexities, storing, and presence of living biomaterials.

Management of skin graft donor site in pediatric patients with tumescent technique and AQUACEL® Ag foam dressing

Split thickness skin graft donor sites are challenging to manage in children because of patient fear and anxiety. Therefore, strategies that minimize the frequency of dressing change are beneficial. This paper describes a technique to simplify wound care for split thickness skin graft donor sites. A tumescent solution of saline containing 0.25% bupivacaine with epinephrine is infiltrated into the graft donor site. Skin grafts are harvested with an electric dermatome. The donor sites are dressed with AQUACEL^® Ag Foam, which is a sodium carboxymethylcellulose hydrofiber dressing that contains silver ions. A total of 17 split thickness skin grafts were performed with this technique. Patient age ranged from 2.4 year to 16.9 years (average 12 years). The AQUACEL^® Ag Foam dressings were removed at an average of 23 days (range 11 to 31 days) at which time complete donor site epithelialization was seen in 13/17 (76.5%) patients. The remaining 4 patients had < 5% of the donor site that had not epithelialized; these went on to heal uneventfully with a brief period of petrolatum gauze dressing changes. Two patients had foul smelling discharge under the dressing that resolved promptly with dressing removal. The above technique allows the primary dressing to stay in place long enough for epithelialization to take place. The obviation of dressing changes in the early post-operative period results in patient comfort and care giver convenience.

Accelerated Wound Closure of Deep Partial Thickness Burns with Acellular Fish Skin Graft

Thermal injuries are caused by exposure to a variety of sources, and split thickness skin grafts are the gold standard treatment for severe burns; however, they may be impossible when there is no donor skin available. Large total body surface area burns leave patients with limited donor site availability and create a need for treatments capable of achieving early and complete coverage that can also retain normal skin function. In this preclinical trial, two cellular and tissue based products (CTPs) are evaluated on twenty-four 5 × 5 deep partial thickness (DPT) burn wounds. Using appropriate pain control methods, DPT burn wounds were created on six anesthetized Yorkshire pigs. Wounds were excised one day post-burn and the bleeding wound beds were subsequently treated with omega-3-rich acellular fish skin graft (FSG) or fetal bovine dermis (FBD). FSG was reapplied after 7 days and wounds healed via secondary intentions. Digital images, non-invasive measurements, and punch biopsies were acquired during rechecks performed on days 7, 14, 21, 28, 45, and 60. Multiple qualitative measurements were also employed, including re-epithelialization, contraction rates, hydration, laser speckle, and trans-epidermal water loss (TEWL). Each treatment produced granulated tissue (GT) that would be receptive to skin grafts, if desired; however, the FSG induced GT 7 days earlier. FSG treatment resulted in faster re-epithelialization and reduced wound size at day 14 compared to FBD (50.2% vs. 23.5% and 93.1% vs. 106.7%, p < 0.005, respectively). No differences in TEWL measurements were observed. The FSG integrated into the wound bed quicker as evidenced by lower hydration values at day 21 (309.7 vs. 2500.4 µS, p < 0.05) and higher blood flow at day 14 (4.9 vs. 3.1 fold change increase over normal skin, p < 0.005). Here we show that FSG integrated faster without increased contraction, resulting in quicker wound closure without skin graft application which suggests FSG improved burn wound healing over FBD.

Wound healing in immunocompromised dogs: A comparison between the healing effects of moist exposed burn ointment and honey

Background and Aim:

Natural topical products have been used to enhance wound healing, especially in immunocompromised animals. The aims of this study were to evaluate and to compare the effects of moist exposed burn ointment (MEBO) and honey on the healing of full-thickness skin wounds in immunocompromised dogs.

Materials and Methods:

The study was conducted using 12 adults, apparently healthy mongrel dogs. Immunosuppression was induced in six dogs by oral administration of prednisone (2 mg/kg) and azathioprine (2 mg/kg), once a day for 21 days. On each dog, a total of 9, 1.5 cm in diameter full-thickness skin circular wounds were created aseptically in the thoracolumbar area under general anesthesia using customized skin punch biopsy kit. In a random fashion, three wounds in each dog were treatment using MEBO (contains b-sitosterol, baicalin, and berberine as active ingredients in a base of beeswax and sesame oil), honey or no treatment (control), once per day for 21 days. Wounds were grossly evaluated once a day for signs of inflammation or infection. In addition, biopsy specimens and digital imaging data of each wound were obtained on days 7, 14, and 21 for histopathological evaluation of the healing process.

Results:

Wounds in immunocompromised dogs appeared to heal significantly in a slower fashion than in non-immunocompromised counterparts. Digital analysis data showed that MEBO-treated wounds expressed better epithelialization area, faster contraction, and smaller wound area percentage when compared with honey-treated wounds. Histopathological analysis showed significantly higher angiogenesis scores in MEBO-treated wounds when compared with other treatments.

Conclusion:

Results of this study showed that MEBO resulted in significant enhancement of wound healing in both healthy and immunocompromised dogs. However, when compared to honey, the wound healing effect of MEBO was superior to that of honey.

Experimental Study of the Effect of Biological Matrixes with Stabilized and Non-Stabilized Platelets on Reparative Process in the Wound Equivalent to Deep Burn

We studied reparative effect of platelet-filled biological matrixes in the treatment of mice with wounds equivalent to deep burn. The wound coatings were based on decellularized dermal matrix without platelets (control), with native platelets, and with platelets stabilized with 2.5 μM nanosilver. In 3 days, the epithelial layer and derma were absent in all groups and extensive scab was formed. Dermal matrix with platelets simulated intensive migration of macrophages and fibroblasts to the wound bottom; in the control group, this migration was absent. In 14 days, granulation tissue appeared in the wound bottom in animals of all groups; in the experimental groups, the number of vessels was 2-4-fold higher than in the control, though the number of inflammatory cells in experimental groups remained high. On day 21, the scab on the most of the wound area was absent in all animals of the experimental groups and epithelialization and hair growth were pronounced, comparing to control. Nevertheless, in experiment dermal layer was not already completed, inflammation reaction remained.

In vitro Antioxidant and in vivo Wound Healing Activities of the 80% Methanol Extract and Solvent Fractions of Seeds of Brassica carinata A. Braun (Brassicaceae) in Mice

Background

Brassica carinata is one of the traditional medicinal plants used in Ethiopia for the treatment of wounds and other diseases. However, the plant has not been scientifically validated, and thus the present study evaluated the in vitro anti-oxidant and the in vivo wound healing activity of the crude extract and solvent fractions of B. carinata seeds in mice.

Materials and Methods

The crude extract was prepared by maceration using 80% methanol and formulated as 5% and 10% w/w ointments for topical application. The acute dermal toxicity was performed in female albino rats based on Organization for Economic Cooperation and Development (OECD) guideline number 434. Excision and incision wound healing models were used to evaluate the wound healing activities of crude extract and solvent fractions ointments in mice. Wound healing parameters such as wound area contraction and the period of epithelialization were determined in an excision model, whereas tensile strength was determined in an incision model. Moreover, the crude extract and solvent fractions were evaluated for the free radical scavenging activities in DPPH assay.

Results

The acute dermal toxicity test showed that a limit dose of 2,000 mg/kg of 10% w/w crude extract ointment did not cause dermal toxicity in mice. In the excision wound model, the data revealed that 10% w/w ointment exhibited a significant wound contraction (from day 6 to 16, P<0.001) effect with a significant decrease in epithelization period (at day 14, P<0.001). In addition, 5% ointment of the crude extract showed a significant effect in wound contraction (from day 8 onwards, P<0.01) and epithelization period (at day 16, P<0.01). Despite all fractions being shown to promote wound healing, 10% w/w aqueous and ethyl acetate fractions showed a significant wound contraction (P<0.001) effect starting from the 4th day onwards. Besides, the maximum antioxidant activity was seen in the aqueous fraction with an IC50 value of 3.45±0.12 mg/mL.

Conclusion

The present study demonstrated that the 80% methanol extract and solvent fractions of the seeds of B.carinata possess potential wound healing and anti-oxidant effects, supporting the traditional use of the plant for wound management.

The Effect of Inflammation on the Healing Process of Acute Skin Wounds Under the Treatment of Wounds with Injections in Rats

PURPOSE

To study the effects of inflammation on the healing process of rats' acute skin wounds during treatment with different injections.

METHODS

The study was carried out on Wistar rats, on which square wounds were simulated in the back region. Four groups of wounds were studied. On the day of the simulation (day 0), solutions of the drugs were injected into the wounds: an isotonic sodium chloride solution (Control group), mesenchymal stem cells (SC group), collagen (Collagen group), and a deproteinized hemoderivative of calf blood (DHB group). Within 2 weeks, the wound healing process was assessed by observing and calculating changes in the wound areas, temperatures, and epithelialization levels. On days 3, 7, and 14, wound tissue samples were taken for histological examination, morphological analysis of the healing process, and quantitative assessment of granulation layers' leukocyte infiltration.

RESULTS

A correlation between the process of inflammation and epithelization during the healing of skin wounds was established. The anti-inflammatory effect of SC injection on the wound edge tissues was determined, as well as the pro-inflammatory effect of DHB, and the absence of effects on the inflammation course under the collagen treatment. Compared to the control group, the transition from the exudative phase of inflammation to the proliferative phase was faster, as well was wound epithelialization in the SC and Collagen groups. A negative correlation between the level of tissue temperature in the center of wounds and their area were recorded, which intensified over time.

CONCLUSION

The severity and duration of the inflammation process during wound healing were ambiguous with the use of different injection treatments. This should compel clinicians to use different markers of drug therapy effectiveness during wound healing. Excessive leukocyte infiltration with a low temperature of wounds and a large scab were markers of delayed wound healing.

USP15 Enhances Re-epithelialization Through Deubiquitinating EIF4A1 During Cutaneous Wound Repair

Re-epithelialization is a fundamental process in wound healing that involves various cytokines and cells during cutaneous barrier reconstruction. Ubiquitin-specific peptidase 15 (USP15), an important member of the deubiquitinating enzymes (DUBs), removes ubiquitin chains from target proteins and maintains protein stability. However, the dynamic role of USP15 in epithelialization remains unclear. We aimed to investigate the regulatory function of USP15 in re-epithelialization. An excisional wound splinting model was established to evaluate the re-epithelialization rate in Usp15 knockout (KO) mice. Coimmunoprecipitation (Co-IP) and mass spectrum analyses were performed to identify USP15-interacting proteins. RNA-sequencing was performed for transcriptome analysis in keratinocytes and uploaded into NODE database (http://www.biosino.org/node, accession numbers: OEP000770 and OEP000763). First, a significant delay in epithelialization was observed in the Usp15 KO mice. Moreover, inhibition of cell migration and proliferation was observed in the USP15-silenced keratinocytes (HaCaTs). Moreover, we revealed for the first time that USP15 could interact with eukaryotic initiation factor 4A-1 (EIF4A1), thereby promoting translational efficacy in keratinocytes, which is essential for keratinocyte proliferation and migration. Conclusively, the USP15-EIF4A1 complex significantly accelerated re-epithelialization in wound healing. These observations helped elucidate the function and mechanisms of USP15 in modulating re-epithelialization in wound healing, providing a promising target for refractory wound treatment.

Depletion of langerin+ cells enhances cutaneous wound healing

Langerin is a C-type lectin receptor that is expressed on Langerhans cells and langerin-positive dermal dendritic cells in the skin. Little is known about the function of langerin⁺ cells in wound healing. In this study, the effects of ablation of langerin⁺ cells on healing of a full-thickness excision wound were investigated using the langerin-DTR depletable mouse. Strikingly, depletion of langerin⁺ cells resulted in more rapid reduction in wound area. Accelerated wound healing in the langerin⁺ -cell-depleted group was characterized by enhanced neo-epidermis and granulation tissue formation, and increased cellular proliferation within the newly formed tissues. Accelerated healing in the absence of langerin⁺ cells was associated with increased levels of granulocyte-macrophage colony-stimulating factor, F4/80⁺ cells and blood vessels within the granulation tissue. These data support an inhibitory role for langerin⁺ cells during wound healing. Therapies that suppress langerin⁺ cells or their function may therefore have utility in progressing the healing of wounds in humans.

The Effect of External Auditory Canal Packing Duration on Healing After Endoscopic Cartilage Myringoplasty

INTRODUCTION

The external auditory canal (EAC) packing is widely used in otosurgery and is considered to promote hemostasis and to support tympanic membrane grafts. However, few studies have investigated the effects of packing removal time on healing.

OBJECTIVE

We investigated the effect of EAC packing duration on healing after endoscopic cartilage myringoplasty in patients with chronic tympanic membrane perforations (TMPs).

MATERIALS AND METHODS

Patients with chronic TMPs who underwent endoscopic "push-through" cartilage myringoplasty were divided into early and late groups based on the length of time before EAC packing was removed. The graft success rate, eardrum appearance, and hearing gain were assessed 3 months after surgery.

RESULTS

The study included 137 patients. Three months after surgery, the graft success rate was 83.5% (66/79) in the early group and 94.8% (55/58) in the late group (P = .042). The graft was displaced in 8 (10.1%) patients in the early group and in 1 (1.7%) patient in the late group (P = .050). No epithelialization was found on the surface of the grafts in the early group, whereas epithelialization was nearly complete 4 weeks after surgery in the late group.

CONCLUSIONS

Delaying removal of the EAC packing after endoscopic cartilage myringoplasty may promote tympanic membrane better healing and cartilage graft epithelialization and improve the appearance of the eardrum.

The ocular surface after simple limbal epithelial transplant (SLET): A high-resolution OCT study of the early postoperative period

Simple limbal epithelial transplantation (SLET) is an emerging technique for treating unilateral limbal stem cell deficiency. We report the high-resolution, anterior segment optical coherence tomography (OCT) features of the first 2 weeks of a patient undergoing SLET for an old acid injury of the right eye, repeatedly from postoperative day 1 through day 14. Three out of 11 explants with the subjacent human amniotic membrane (hAM) and the overlaid bandage contact lens were imaged. The hAM was intact and of the same thickness throughout the study period; the sub-hAM space increased from day 3 to 9 and disappeared by day 10; the explants started thinning from day 3 with the fibrin around them starting to decrease from day 2 and completely disappeared by day 4. Epithelialization occurred between day 8 and 14 and proceeded more rapidly towards the limbus than centrally. There was no change of the corneal stromal thickness or reflectivity. This case report uses high-definition, spectral-domain OCT to document the events on the ocular surface after a successful SLET surgery and opens up an avenue to study epithelialization in a convenient and noninvasive manner.

Tissue Augmentation in Wound Healing: the Role of Endothelial and Epithelial Cells

Introduction

Wounds and their complications present a frequent cause of morbidity and mortality in everyday clinical practice. In order to reduce the wound burden, much effort has been directed into the physiology of healing and new therapeutic approaches.

Aim

This paper provides an overview from the literature about the role of endothelial and epithelial cells in tissue filler employment for wound healing.

Material and Methods

The scientific literature was reviewed through PubMed, Medline and Science Direct. The articles were chosen in correlation with the study objective and their scientific relevance.

Results

Successful wound healing depends on many diverse processes, cell types and molecular mediators. The definitive aim of wound healing is a properly healed wound. Tissue fillers are becoming an important alternative in wound management, although augmentation of soft tissue can present a demanding problem due to the difficulties in tissue survival. In order to prevent its failure, an optimal vascular network needs to form from wound edges into the filler.

Conclusions

Because of the importance of chemotaxis and angiogenesis in various physiological and pathological processes, both events present an extensive area of intense research. Additionally, epithelial cells are needed to cover the wound defect and sealing the wound environment from outer world.

Cdc42 Effector Protein 3 Interacts With Cdc42 in Regulating Xenopus Somite Segmentation

Somitogenesis is a critical process during vertebrate development that establishes the segmented body plan and gives rise to the vertebra, skeletal muscles, and dermis. While segmentation clock and wave front mechanisms have been elucidated to control the size and time of somite formation, regulation of the segmentation process that physically separates somites is not understood in detail. Here, we identified a cytoskeletal player, Cdc42 effector protein 3 (Cdc42ep3, CEP3) that is required for somite segmentation in Xenopus embryos. CEP3 is specifically expressed in somite tissue during somite segmentation. Loss-of-function experiments showed that CEP3 is not required for the specification of paraxial mesoderm, nor the differentiation of muscle cells, but is required for the segmentation process. Live imaging analysis further revealed that CEP3 is required for cell shape changes and alignment during somitogenesis. When CEP3 was knocked down, somitic cells did not elongate efficiently along the mediolateral axis and failed to undertake the 90° rotation. As a result, cells remained in a continuous sheet without an apparent segmentation cleft. CEP3 likely interacts with Cdc42 during this process, and both increased and decreased Cdc42 activity led to defective somite segmentation. Segmentation defects caused by Cdc42 knockdown can be partially rescued by the overexpression of CEP3. Conversely, loss of CEP3 resulted in the maintenance of high levels of Cdc42 activity at the cell membrane, which is normally reduced during and after somite segmentation. These results suggest that there is a feedback regulation between Cdc42 and CEP3 during somite segmentation and the activity of Cdc42 needs to be fine-tuned to control the coordinated cell shape changes and movement required for somite segmentation.

Stable Tracheal Regeneration Using Organotypically Cultured Tissue Composed of Autologous Chondrocytes and Epithelial Cells in Beagles

OBJECTIVES

In tracheal regeneration, the slow process of epithelialization is often a barrier to the stability and safety of the transplanted trachea. The aim of this study was to examine a new tracheal regeneration technique using organotypically cultured tissue composed of autologous cells.

METHODS

Nine beagles were prepared. Chondrocytes from auricular cartilage and epithelial cells from buccal mucosa were isolated and cultured. Tissue-engineered cartilages were fabricated with chondrocytes at a density of 1 × 10⁷ cells/mL (high-density group) and 1 × 10⁶ cells/mL (low-density group). A fabricated epithelial cell sheet was laid on a poly(lactic-co-glycolic acid) block in atelocollagen gel containing the chondrocytes, and the organotypically cultured tissues were transplanted into a partially resected trachea. The control group had only the block transplanted.

RESULTS

The tissue-engineered cartilages in the high-density group contained many viable chondrocytes and many cartilage matrices. The low-density group had abundant collagen fibers and no chondrocytes. Tracheal endoscopy revealed no deformation or atrophy at the transplant site in the high-density group. Histologically, partially hyaline cartilages covered with epithelium and lamina propria were found in the high-density group but not in the low-density and control groups.

CONCLUSIONS

Stable tracheal regeneration was achieved using organotypically cultured tissue fabricated with autologous high-density chondrocytes and epithelial cells.

Acellular dermal matrix contributes to epithelialization in patients with chronic sinusitis

BACKGROUND

Nasal endoscopic surgery is widely used for nasal diseases, including sinusitis and tumors. However, scar hyperplasia, nasal irritation, scab, and nasal obstruction delay nasal mucosal recovery, with prolonged cleaning exacerbating the patient's financial burden. Here, we presented a novel approach for the treatment of nasal mucosal defects, termed acellular dermal matrix.

METHODS

A total of 31 patients with bilateral chronic sinusitis (maxillary sinusitis and ethmoid sinusitis) underwent nasal surgery and nasal mucosal repair in September-October 2016. We divided the nasal cavities of each patient into control and acellular dermal matrix groups, randomly selected one side for nasal mucosal repair by surgery. A suitable acellular dermal matrix size was selected according to the defect in each patient. After pruning, the acellular dermal matrix was placed on the wound surface and filled with gelatin sponge. All patients were followed up for 14 weeks to compare nasal mucosal epithelialization between the control and acellular dermal matrix groups. Results：No obvious complications and adverse reactions were observed after nasal surgery. Lund-Kennedy scores in the acellular dermal matrix group were significantly decreased compared with the control group at 8 (0 (0, 1) vs. 2 (2, 4); P<0.05) weeks. Epithelialization time of eight weeks in the acellular dermal matrix groups was significantly decreased than the control group of 14 weeks.

CONCLUSION

Acellular dermal matrix provides a growth framework for the healthy mucosa on the wounded surface and reduces postoperative epithelialization time.

PEG-Plasma Hydrogels Increase Epithelialization Using a Human Ex Vivo Skin Model

In vitro cell culture methods are used extensively to study cellular migration, proliferation, and differentiation, which play major roles in wound healing but the results often do not translate to the in vivo environment. One alternative would be to establish an ex vivo model utilizing human discarded skin to evaluate therapies in a more natural setting. The purpose of this study was to institute such a model by creating ‘wounds’ in the center of a piece of discarded skin and treating them with three different biomaterials: collagen, polyethylene glycol (PEG)-fibrin, or PEG-platelet free plasma (PFP). Explants were cultured for 14 days with supernatant and microscopy images collected every 3 days to assess cytotoxicity and epithelialization. After 14 days, the explants were fixed, sectioned, and stained for cytokeratin-10 (CK-10), alpha-smooth muscle actin (α-SMA), and wheat germ (WG). Compared to controls, similar levels of cytotoxicity were detected for 12 days which decreased slightly at day 14. The PEG-PFP hydrogel-treated wounds epithelialized faster than other treatments at days 6 to 14. A 6-8 cell layer thick CK-10+ stratified epidermis had developed over the PEG-PFP hydrogel and cells co-stained by WG and α-SMA were observed within the hydrogel. An ex vivo model was established that can be used practically to screen different therapies exploring wound healing.

Cryopreserved limbal lamellar keratoplasty for peripheral corneal and limbal reconstruction

This study aimed to evaluate the outcomes and described the recovery process of cryopreserved limbal lamellar keratoplasty (CLLK) for peripheral corneal and limbal diseases. Thirteen eyes of 12 patients with a mean age of 41±23.9y were included. The average follow-up was 12.1±5.6mo. Stable ocular surface was achieved in all eyes at last follow-up. Epithelialization originated from both recipient and graft in 9 eyes. We conclude that CLLK compensates for the shortage of donor corneas and cryopreserved limbal grafts provide epithelialization sources in ocular surface reconstruction.

Oxytocin effects on experimental skin wound healing

OBJECTIVE

Oxytocin (OXY) has significant effects on mammalian behavior. Next to its role in lactation and social interactions, it is described to support better wound healing as well. However, direct OXY effects on wound healing and the regeneration of the microvascular network are still not clarified. We therefore examined the effects of OXY and an OXY receptor antagonist [atosiban (ATO)] on skin wound healing, focusing on epithelialization and neovascularization.

METHODS

Skin wound healing has been assessed using intravital fluorescence microscopy in a model of full dermal thickness wounds in the dorsal skin fold chamber of hairless mice. Animals received repetitive low or high doses of OXY or ATO. Morphological and cellular characterization of skin tissue repair was performed by histology and in vitro cell assays.

RESULTS

The assessment of skin tissue repair using this therapy regimen showed that OXY and ATO had no major influence on epithelialization, neovascularization, wound cellularity, or inflammation. Moreover, OXY and ATO did neither stimulate nor deteriorate keratinocyte or fibroblast migration and proliferation.

CONCLUSION

In summary, this study is the first to demonstrate that OXY application does not impair skin wound healing or cell behavior. However, until now, the used transmitter system seems not to be clarified in detail, and it might be proposed that it is associated with the stress response of the organism to various stimuli.

Comparative cost and clinical effectiveness of clostridial collagenase ointment for chronic dermal ulcers

Chronic dermal ulcers affect approximately 2.4-4.5 million people in the USA and are associated with loss of function, decreased quality of life and significant economic burden. Debridement is a critical component of wound care involving removal of nonviable tissue from chronic wounds to stimulate the granulation and epithelialization process. Clostridial collagenase ointment has been used as a method of wound debridement for more than 50 years and is currently the only enzymatic debriding ointment with US FDA approval. This review discusses the results of recent real-world studies that build upon the evidence demonstrating the clinical effectiveness, cost-effectiveness and safety of clostridial collagenase ointment across wound types and care settings.

Pigment epithelium-derived factor short peptides facilitate full-thickness cutaneous wound healing by promoting epithelial basal cell and hair follicle stem cell proliferation

A previous study by our group showed that a 44-amino-acid fragment of pigment epithelium-derived factor (PEDF) facilitated corneal epithelial wound healing. In the present study this fragment was shortened to obtain peptides of 18, 20 and 29 amino acids in length, and their promoting effects on the healing of full-thickness skin wounds were assessed. Peptides were delivered periodically by topical application to punch wounds of mice. The wound healing speed was evaluated by measuring the reduction of wound areas at 4 and 7 days after injury. Histological analysis with Masson's trichrome staining was used to confirm epithelialization and dermal collagen deposition. Proliferation of epithelial basal cells was documented by 5-bromo-2′-deoxyuridine incorporation. Hair follicle stem cells were identified by immunostaining for leucine-rich repeat-containing G protein-coupled receptor 6. The results indicated that the 20- and 29-amino-acid short peptides significantly reduced the time required for wound healing compared to the vehicle. Histological analysis confirmed faster epithelial cell coverage of open wounds. Treatment with the PEDF peptide fragments also contributed to granulation, tissue formation by increasing the fibroblast population and enhancing collagen deposition in the dermis. Wounds treated with PEDF peptide fragments contained more basal cells proliferated in the epithelium. Moreover, hair follicle stem cells were also stimulated to proliferate by peptide exposure. In conclusion, the present study reported the identification of two short peptides that can enhance the healing of full-thickness skin wounds following topical application. The underlying mechanisms may involve activation of basal cell proliferation and mobilization of hair follicle stem cells.

Comparative Effectiveness of Clostridial Collagenase Ointment to Medicinal Honey for Treatment of Pressure Ulcers

Objective: Compare enzymatic debridement using clostridial collagenase ointment (CCO) with autolytic debridement using medicinal honey in the hospital outpatient setting for treating pressure ulcers (PUs).

Approach: Retrospective deidentified electronic health records from 2007–2013 were extracted from the U.S. Wound Registry. Propensity score matching followed by multivariable analyses was used to adjust for selection bias and assess treatment effects comparing CCO-treated versus honey-treated PUs. Key outcomes included 100% granulation and epithelialization at 1 year.

Results: Five hundred seventeen CCO-treated PUs (446 patients) were matched to corresponding honey-treated PUs (341 patients). The majority of PUs were stage III (CCO 56%, honey 55%). CCO users had significantly fewer total visits (9.1 vs. 12.6; p < 0.001), fewer total selective sharp debridements (2.7 vs. 4.4; p < 0.001), and fewer PUs receiving negative pressure wound therapy (29% vs. 38%; p = 0.002) compared with honey.

Innovation: CCO-treated PUs were 38% more likely to achieve 100% granulation compared to honey-treated PUs at 1 year, p = 0.018. Mean days to 100% granulation were significantly lower for CCO-treated PUs (255 vs. 282 days, p < 0.001). CCO-treated PUs were 47% (p = 0.024) more likely to epithelialize at 1 year compared to PUs treated with honey. Mean days to epithelialization were significantly lower for PUs treated with CCO at 1 year (288 vs. 308 days; p = 0.011).

Conclusion: All stages of PUs treated with CCO achieved faster rates of granulation and subsequent epithelialization compared to PUs treated with medicinal honey as measured by real-world data collected in the hospital outpatient department care setting.

High-frequency pulsed low-level diode laser therapy accelerates wound healing of tooth extraction socket: An in vivo study

BACKGROUND AND OBJECTIVE

This study aimed to evaluate the effects of high-frequency pulsed (HiFP) low-level laser therapy (LLLT) on early wound healing of tooth extraction sockets in rats.

STUDY DESIGN/MATERIALS AND METHODS

Bilateral maxillary first molars were extracted from 6-week-old Sprague-Dawley rats. Sockets on the right were treated by HiFP low-level diode laser irradiation (904-910 nm); the left sides served as unirradiated controls. LLLT (0.28 W, 30 kHz, 200-ns pulse, 0.6% duty cycle, 61.2 J/cm² total power density) was employed immediately after extraction and every 24 hours thereafter. The maxillae including the sockets were resected 3 or 7 days after extraction. Soft-tissue healing was evaluated on days 0, 3, and 7. The bone mineral content (BMC), bone volume (BV), and bone mineral density (BMD) of the extraction sockets were evaluated by microcomputed tomography, and histomorphometric analysis was carried out on day 7. Real-time PCR analysis of osteogenic marker expression and immunohistochemical detection of proliferating cell nuclear antigen (PCNA)-positive cells were performed on day 3.

RESULTS

Compared with control sites, the un-epithelialized areas of the extracted sites were significantly reduced by irradiation (P = 0.04), and the BMC, BV, and BMD of laser-treated sites were significantly increased (P = 0.004, 0.006, and 0.009, respectively). On day 7, the mean height of newly formed immature woven bone was higher in laser-treated sites (P = 0.24). On day 3, laser-treated sites showed significantly higher osteocalcin mRNA expression (P = 0.04) and PCNA-positive cell numbers (P = 0.01).

CONCLUSION

HiFP low-level diode laser irradiation enhanced soft- and hard-tissue healing of tooth extraction sockets. Lasers Surg. Med. 48:955-964, 2016. © 2016 Wiley Periodicals, Inc.

Intercellular Adhesion-Dependent Cell Survival and ROCK-Regulated Actomyosin-Driven Forces Mediate Self-Formation of a Retinal Organoid

In this study we dissected retinal organoid morphogenesis in human embryonic stem cell (hESC)-derived cultures and established a convenient method for isolating large quantities of retinal organoids for modeling human retinal development and disease. Epithelialized cysts were generated via floating culture of clumps of Matrigel/hESCs. Upon spontaneous attachment and spreading of the cysts, patterned retinal monolayers with tight junctions formed. Dispase-mediated detachment of the monolayers and subsequent floating culture led to self-formation of retinal organoids comprising patterned neuroretina, ciliary margin, and retinal pigment epithelium. Intercellular adhesion-dependent cell survival and ROCK-regulated actomyosin-driven forces are required for the self-organization. Our data supports a hypothesis that newly specified neuroretina progenitors form characteristic structures in equilibrium through minimization of cell surface tension. In long-term culture, the retinal organoids autonomously generated stratified retinal tissues, including photoreceptors with ultrastructure of outer segments. Our system requires minimal manual manipulation, has been validated in two lines of human pluripotent stem cells, and provides insight into optic cup invagination in vivo.

•

Established a method for isolating large amounts of retinal organoids from hESCs

•

Dispase-mediated cell detachment led to self-formation of the retinal organoids

•

Intercellular adhesions in the floating cultures are required for cell survival

•

ROCK-regulated actomyosin-driven forces are required for the self-organization

UV fluorescence excitation imaging of healing of wounds in skin: Evaluation of wound closure in organ culture model

BACKGROUND AND OBJECTIVE

Molecules native to tissue that fluoresce upon light excitation can serve as reporters of cellular activity and protein structure. In skin, the fluorescence ascribed to tryptophan is a marker of cellular proliferation, whereas the fluorescence ascribed to cross-links of collagen is a structural marker. In this work, we introduce and demonstrate a simple but robust optical method to image the functional process of epithelialization and the exposed dermal collagen in wound healing of human skin in an organ culture model.

MATERIALS AND METHODS

Non-closing non-grafted, partial closing non-grafted, and grafted wounds were created in ex vivo human skin and kept in culture. A wide-field UV fluorescence excitation imaging system was used to visualize epithelialization of the exposed dermis and quantitate wound area, closure, and gap. Histology (H&E staining) was also used to evaluate epithelialization.

RESULTS

The endogenous fluorescence excitation of cross-links of collagen at 335 nm clearly shows the dermis missing epithelium, while the endogenous fluorescence excitation of tryptophan at 295 nm shows keratinocytes in higher proliferating state. The size of the non-closing wound was 11.4 ± 1.8 mm and remained constant during the observation period, while the partial-close wound reached 65.5 ± 4.9% closure by day 16. Evaluations of wound gaps using fluorescence excitation images and histology images are in agreement.

CONCLUSIONS

We have established a fluorescence imaging method for studying epithelialization processes, evaluating keratinocyte proliferation, and quantitating closure during wound healing of skin in an organ culture model: the dermal fluorescence of pepsin-digestible collagen cross-links can be used to quantitate wound size, closure extents, and gaps; and, the epidermal fluorescence ascribed to tryptophan can be used to monitor and quantitate functional states of epithelialization. UV fluorescence excitation imaging has the potential to become a valuable tool for research, diagnostic and educational purposes on evaluating the healing of wounds. Lasers Surg. Med. 48:678-685, 2016. © 2016 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.

Formins at the Junction

The actin cytoskeleton and adhesion junctions are physically and functionally coupled at the cell-cell interface between epithelial cells. The actin regulatory complex Arp2/3 has an established role in the turnover of junctional actin; however, the role of formins, the largest group of actin regulators, is less clear. Formins dynamically shape the actin cytoskeleton and have various functions within cells. In this review we describe recent progress on how formins regulate actin dynamics at cell-cell contacts and highlight formin functions during polarized protein traffic necessary for epithelialization.

Amniotic epithelial cells promote wound healing in mice through high epithelialization and engraftment

Although human amniotic epithelial cells (AMEs) are an attractive source of stem cells, their therapeutic potential in wound healing has not been fully investigated. We evaluated the therapeutic potential of AMEs for wound healing. Real-time PCR showed that the epithelialization growth factors epidermal growth factor (EGF), platelet-derived growth factor (PDGF)-B and chemotactic factors interleukin-8 (IL-8 or CXCL8) and neutrophil-activating protein-2 (NAP-2 or CXCL7) were upregulated in AMEs compared with adipose-derived mesenchymal stem cells (ADMs). In vitro scratch wound assays revealed that AME-derived conditioned medium substantially accelerated wound closure. Wounds in NOD/SCID mice were created by skin excision, followed by AME transplantation. AMEs implantation significantly accelerated wound healing and increased cellularity and re-epithelialization. Transplanted AMEs exhibited high engraftment rates and expressed keratinocyte-specific proteins and cytokeratin in the wound area, suggesting direct benefits for cutaneous closure. Taken together, these data indicate that AMEs possess therapeutic capability for wound healing through the secretion of epithelialization growth factors and enhanced engraftment properties. Copyright © 2015 John Wiley & Sons, Ltd.

Wound healing: a new perspective on glucosylated tetrahydrocurcumin

Wound healing represents a dynamic set of coordinated physiological processes observed in response to tissue injury. Several natural products are known to accelerate the process of wound healing. Tetrahydrocurcumin (THC), an in vivo biotransformed product/metabolite of curcumin, is known to exhibit a wide spectrum of biological activities similar to those of native curcuminoids. The poor bioavailability of these curcuminoids limits their clinical applications. The present study highlights the percutaneous absorption and wound healing activity of glucosyl-conjugated THC (glucosyl-THC) in male Wistar rats. A high plasma concentration of glucosyl-THC (4.35 μg/mL) was found in rats 3 hours after application. A significant enhanced wound healing activity and reduced epithelialization time were observed in rats that received glucosyl-THC. This may have been due to the improved bioavailability of the glucosyl compound. The nonstaining and lack of skin-sensitive side effects render the bioconjugated glucosyl-THC a promising therapeutic compound in the management of excision wounds and in cosmetic applications, in the near future.

Evaluation of the antioxidant activity and the healing action of the ethanol extract of Calotropis procera bark against surgical wounds

The objective of the present study was to evaluate the antioxidant potential and the wound healing effect of the ethanolic extract of the bark of Calotropis procera. The antioxidant study was evaluated in vitro, using 2,2-diphenylpicrylhydrazyl (DPPH) and deoxyribose degradation assays. Wound healing was studied using excision and incision wound on normal and dexamethasone-suppressed wound healing rodent models. Alkaloids, flavonoids, proteins and phenols were screened in the extract used whereas saponins and true tannins were absent. The extract contains only 12.5 gallic acid equivalent and 399.54 rutin equivalent. It was found to inhibit DPPH and deoxyribose oxidation (IC₅₀ = 24.24 and 5.40 respectively). In vivo study demonstrated a significant reduction in the epithelialization time (P < 0.001) to 17-18 days in normal and dexamethasone treated rats following the ethanolic extract of the bark of C. procera application. The same extract also significantly increased the breaking strength in dexamethasone treated rats. Histological examination of incision wounds of treated group showed matured extracellular matrix, numerous fibroblasts. This study illustrated an excellent potential of the bark of C. procera therapy on dermal wound healing, with a tentative mechanism of action related to improved collagen deposition and reduced inflammatory reaction.

Clinical Experience with Chitosan Matrix and Cultured Fibroblasts for Burns

Introduction

Burns are an important public health challenge due to the frequency of getting burns in day-to-day life, occupational hazards, and catastrophes. Treatment of burns is complex and is associated with high morbidity and mortality. Duration and complexity of burn treatment require finding new ways of curing and rehabilitating burns. The result of burn treatment plays a significant role in post-traumatic status of a patient and his or her consequent adaptation in society. Chitosan is a natural safe non-toxic product compatible with human tissues, characterized by hydrosorbid, anticoagulant, antibacterial, and wound healing features. The study aims to show a clinical application of chitosan-pectin scaffold with cultured human skin fibroblasts in the treatment of deep burns.

Methods

The substrate was prepared by dissolving 3% chitosan in 0.5N acetic acid, which was then mixed with 3% solution of pectin dissolved in distillated water. Chitosan film was formed in a Petri dish for 20–24 hours at 20–25 °C. After drying the film, cultured allogeneic fibroblasts (patent number RK-25091) were seeded on its surface.

Results

The results from an in vitro culture study showed that human allogeneic fibroblasts could adhere well and grow on the selected scaffold with a typical morphology. During autodermoplasty surgery, cultured allogeneic fibroblasts were applied on granulating wounds of 9 patients with IIIA to IVB degree burns and limited donor resources. Wounds treated with the fibroblastseeded scaffold among all patients provided the highest level of re-epithelialization (day 5), in comparison to cell-free scaffold (day 7) and untreated surface of wounds (day 10).

Conclusion

Our results indicate the potential use of chitosan for wound healing due to its allogenic fibroblast adherence to scaffolding as well as high epithelization. This warrants further studies on chitosan for use in wounds resulting from third and fourth degree burns.

Neurolaena lobata L. promotes wound healing in Sprague Dawley rats

Background:

The leaves of the Neurolaena lobata (Asteraceae) plant are used to control diabetes and heal wounds and infections.

Aim:

The ethanolic extract of N. lobata leaf was evaluated for its ability to heal inflicted wounds in rats using the excision wound model.

Materials and Methods:

Animals were divided into three groups of six each. Test group animals were treated topically with an ethanolic extract of N. lobata (1:1 with petroleum jelly, 100 mg/kg/day). Standard and control group animals were treated with mupirocin and petroleum jelly, respectively. Treatment was given for 13 days and the wound area was measured on alternate days. Parameters of healing assessed were the rate of wound contraction, period of epithelialization and hydroxyproline content. Antimicrobial activity of the extract was observed against Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli.

Results:

Phytochemical analysis of the extract showed the presence of saponins, tannins, alkaloids and flavanoids. Extract-treated animals exhibited 87% reduction in the wound area over 13 days when compared with the control (78%) and standard (83%) groups (P < 0.05). A significant decrease in the epithelialization period was noticed with the extract-treated test group animals compared with the controls and the standard group animals (P < 0.008). The hydroxyproline content of the extract-treated animals was higher (230.5 ± 42.1) when evaluated against the control and (79.0 ± 32.2) and the standard (115.0 ± 44.5) groups (P < 0.05).

Conclusion:

Increase in the rate of wound contraction and hydroxyproline content with decrease in epithelialization time in extract-treated animals support further evaluation of N. lobata as a pharmacotherapy for wound healing.

Efficacy of Acorus calamus on collagen maturation on full thickness cutaneous wounds in rats

Background:

The rhizomes of Acorus calamus and their essential oil are widely used in the flavoring industry and production of alcoholic beverages in Europe. Recent reports have confirmed the presence of several pharmacological components in the rhizomes of A. calamus.

Objective:

The objective of this study was to find out the efficacy of topical administration of ethanolic extract of A. calamus on dermal wound healing in rats. Wound healing is a natural process occurring in living organisms, which results in a complete or partial remodeling of injured tissue and ultimately progresses to the formation of a fibrous scar. Several natural products have been reported to augment the wound healing process.

Materials and Methods:

An ethanolic extract of A. calamus was prepared and its wound-healing efficacy was studied. An excision wound was made on the back of the rat and 200 μL (40 mg/kg body weight) of the A. calamus extract was applied topically once daily for the treated wounds. The control wounds were treated with 200 μL of phosphate buffered saline.

Results:

The granulation tissues formed were removed at 4, 8 and 12 days and biochemical parameters such as deoxyribonucleic acid, total protein, total collagen, hexosamine and uronic acids were measured. The amount of type I/III collagen formed in control and treated wound tissues was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The epithelialization time, tensile strength and histological examination of the wounds were also studied. Biochemical analyses of the granulation tissues revealed a significant increase in collagen, hexosamine and uronic acid when compared with the control. The tensile strength of extract treated wounds was found to increase by 112%. A significant reduction in lipid peroxide levels suggested that A. calamus possesses antioxidant components.

Conclusions:

The results strongly confirm the beneficial effects of A. calamus in augmenting the wound healing process.