The Wound Healing Process

A mathematical model for wound healing in the reef-building coral Pocillopora damicornis

Coral reefs, among the most diverse ecosystems on Earth, currently face major threats from pollution, unsustainable fishing practices , and perturbations in environmental parameters brought on by climate change. Corals also sustain regular wounding from other sea life and human activity. Recent reef restoration practices have even involved intentional wounding by systematically breaking coral fragments and relocating them to revitalize damaged reefs, a practice known as microfragmentation. Despite its importance, very little research has explored the inner mechanisms of wound healing in corals. Some reef-building corals have been observed to initiate an immunological response to wounding similar to that observed in mammalian species. Utilizing prior models of wound healing in mammalian species as the mathematical basis, we formulated a mechanistic model of wound healing, including observations of the immune response and tissue repair in scleractinian corals for the species Pocillopora damicornis. The model consists of four differential equations which track changes in remaining wound debris, number of cells involved in inflammation, number of cells involved in proliferation, and amount of wound closure through re-epithelialization. The model is fit to experimental wound size data from linear and circular shaped wounds on a live coral fragment. Mathematical methods, including numerical simulations and local sensitivity analysis, were used to analyze the resulting model. The parameter space was also explored to investigate drivers of other possible wound outcomes. This model serves as a first step in generating mathematical models for wound healing in corals that will not only aid in the understanding of wound healing as a whole, but also help optimize reef restoration practices and predict recovery behavior after major wounding events.

Recombinant human amelogenin promotes wound healing by enhancing angiogenesis

The first barrier of the human body is the skin, and more serious harm may occur when skin wound healing is delayed. One of the components of enamel matrix proteins is amelogenin, which inhibits inflammation and promotes periodontal tissue regeneration. However, its role in skin wound healing and angiogenesis is inconclusive. Thus, this study aimed to assess the therapeutic effect of recombinant human amelogenin (rhAM) on mouse skin wounds and to determine its effect on angiogenesis and its underlying mechanism. rhAM was expressed in Escherichia coli and purified using the optimized acetic acid method. A skin injury mouse model was established to explore the effects of rhAM on skin wound healing. After treatment with rhAM for 7 days, the wound healing rate was calculated, and the therapeutic effect of rhAM on skin wounds was assessed using hematoxylin & eosin (HE), Masson, and CD31 immunofluorescence staining. The expression of growth and inflammatory factors in wound tissues were detected using Western Blot. In addition, the rhAM effects on the proliferation and migration of human umbilical vein endothelial cells (HUVEC) and mouse fibroblasts (NIH 3T3) were studied in vitro using the Cell Counting Kit-8, cell scratch, cytoskeleton staining, and qPCR. The rhAM effect on HUVEC angiogenesis and its potential mechanism was studied using tube formation and Western Blot. The results showed that the purity of the obtained rhAM was more than 90 % using the optimized acetic acid method, and high-dose rhAM treatment could improve wound healing rate in mice. Additionally, more blood vessels and collagen were produced in the skin wound, and the expression of angiopoietin-related protein 2 (ANGPTL2) and transforming growth factor (TGF)-β1 was upregulated; however, that of interleukin-6 was down-regulated. We also found that rhAM promoted the proliferation and migration of HUVEC and NIH 3T3, the mRNA levels of vascular endothelial growth factor (VEGF), fibroblast growth factor, TGF-β1 and ANGPTL2 in HUVEC cells were upregulated, and expression of VEGF and phosphorylation of the p38 mitogen-activated protein kinase were activated. Therefore, rhAM could promote skin wound healing by upregulating angiogenesis and inhibiting inflammation.

Application of metal-organic frameworks in infectious wound healing

Metal-organic frameworks (MOFs) are metal-organic skeleton compounds composed of self-assembled metal ions or clusters and organic ligands. MOF materials often have porous structures, high specific surface areas, uniform and adjustable pores, high surface activity and easy modification and have a wide range of prospects for application. MOFs have been widely used. In recent years, with the continuous expansion of MOF materials, they have also achieved remarkable results in the field of antimicrobial agents. In this review, the structural composition and synthetic modification of MOF materials are introduced in detail, and the antimicrobial mechanisms and applications of these materials in the healing of infected wounds are described. Moreover, the opportunities and challenges encountered in the development of MOF materials are presented, and we expect that additional MOF materials with high biosafety and efficient antimicrobial capacity will be developed in the future.

Nanocellulose-based platforms as a multipurpose carrier for drug and bioactive compounds: From active packaging to transdermal and anticancer applications

The nanocellulose has unique characteristics, such as biocompatibility, good mechanical strength, and low cytotoxicity. The nanocellulose crystalline portion is responsible for good mechanical resistance, while the amorphous portion is responsible for flexibility. Such features make it a promising candidate for multiple applications related to the modulation of substance release: targeted cancer therapy, transdermal drug delivery, and controlled-release packaging materials. Thus, in this study, we discussed nanocellulose as a multipurpose material for drug delivery and bioactive compound carriers in controlled delivery systems with varied applications in pharmaceutic fields. Herein, we focus on understanding key factors such as i) polymer-drug interactions and surface modification strategies in controlled release rates, ii) therapeutic efficacy, and iii) biocompatibility aspects. The tunable chemistry surface plays a fundamental approach limiting the quick release of active substances in drug delivery systems. Several works on a pre-clinical stage of investigation were overviewed, reporting robust evidence on nanocellulose to design bioactive compounds/drug delivery carriers based on stimuli-responsive drug release and controlled delivery systems for higher efficiency in cancer therapies, purposing target therapy and reduced side effects. Nanocellulose was also identified as a solid candidate material in active packaging for pharmaceutical products. Cellulose nanocrystals and bacterial cellulose demonstrated strong potential to overcome the challenge of controlled release profile and open novel insights in advanced active packaging materials for pharmaceutics with controlled release of antioxidant and antimicrobial substances. Moreover, the concept overview in this work might be extended in active food packaging technologies to flavor-releasing/absorbing systems or antimicrobial/antioxidant carriers for extending the shelf life of foods.

Wound-healing effect of topical nanoemulsion-loaded cream and gel formulations of Hippophae rhamnoides L. (sea buckthorn) fruit oil and their acute dermal toxicity study on female SD rats

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of topical nanoemulsion (NE)-loaded cream and gel formulations of Hippophae rhamnoides L. (sea buckthorn [SBT]) fruit oil for wound healing.

MATERIALS AND METHODS

The NE-loaded cream and gel formulations of H. rhamnoides L. (SBT) fruit oil (IPHRFH) were prepared and evaluated for their wound-healing activity on female Sprague-Dawley (SD) rats. They were further divided into groups (seven) and the wound-healing activity was determined by measuring the area of the wound on the wounding day and on the 0th, 4th, 8th, and 10th days. The acute dermal toxicity of the formulations was assessed by observing the erythema, edema, and body weight (BW) of the rats.

RESULTS

The topical NE cream and gel formulations of H. rhamnoides L. (SBT) fruit oil showed significant wound-healing activity in female SD rats. The cream formulation of IPHRFH showed 78.96%, the gel showed 72.59% wound contraction on the 8th day, whereas the positive control soframycin (1% w/w framycetin) had 62.29% wound contraction on the 8th day. The formulations also showed a good acute dermal toxicity profile with no changes significantly affecting BW and dermal alterations.

CONCLUSIONS

The results of this study indicate that topical NE-loaded cream and gel formulation of H. rhamnoides L. (SBT) fruit oil are safe and effective for wound healing. The formulations showed no signs of acute dermal toxicity in female SD rats.

Aging Skin and Wound Healing

Responsible for many essential functions of life, human skin is made up of many components, each of which undergoes significant functional changes with aging and photodamage. Wound healing was previously thought to be defective in the elderly given the higher presence of chronic wounds and the longer time required for re-epithelialization of acute wounds. However, these notions have been challenged in recent research, which has shown that wound healing in the elderly is delayed but not defective. Poor healing of chronic wounds in older populations is more often attributable to comorbid conditions rather than age alone.

Nature-Derived Polysaccharide-Based Composite Hydrogels for Promoting Wound Healing

Numerous innovative advancements in dressing technology for wound healing have emerged. Among the various types of wound dressings available, hydrogel dressings, structured with a three-dimensional network and composed of predominantly hydrophilic components, are widely used for wound care due to their remarkable capacity to absorb abundant wound exudate, maintain a moisture environment, provide soothing and cooling effects, and mimic the extracellular matrix. Composite hydrogel dressings, one of the evolved dressings, address the limitations of traditional hydrogel dressings by incorporating additional components, including particles, fibers, fabrics, or foams, within the hydrogels, effectively promoting wound treatment and healing. The added elements enhance the features or add specific functionalities of the dressings, such as sensitivity to external factors, adhesiveness, mechanical strength, control over the release of therapeutic agents, antioxidant and antimicrobial properties, and tissue regeneration behavior. They can be categorized as natural or synthetic based on the origin of the main components of the hydrogel network. This review focuses on recent research on developing natural polysaccharide-based composite hydrogel wound dressings. It explores their preparation and composition, the reinforcement materials integrated into hydrogels, and therapeutic agents. Furthermore, it discusses their features and the specific types of wounds where applied.

NIR-activated quercetin-based nanogels embedded with CuS nanoclusters for the treatment of drug-resistant biofilms and accelerated chronic wound healing

We have developed multifunctional nanogels with antimicrobial, antioxidant, and anti-inflammatory properties, facilitating rapid wound healing. To prepare the multifunctional nanogels, we utilized quercetin (Qu) and a mild carbonization process to form carbonized nanogels (CNGs). These CNGs possess excellent antioxidative and bacterial targeting properties. Subsequently, we utilized the Qu-CNGs as templates to prepare nanogels incorporating copper sulfide (CuS) nanoclusters, further enhancing their functionality. Notably, the CuS/Qu-CNGs nanocomposites demonstrated an exceptional minimum inhibitory concentration against tested bacteria, approximately 125-fold lower than monomeric Qu or Qu-CNGs. This enhanced antimicrobial effect was achieved by leveraging near-infrared II (NIR-II) light irradiation. Additionally, the CuS/Qu-CNGs exhibited efficient penetration into the extracellular biofilm matrix, eradicating methicillin-resistant Staphylococcus aureus-associated biofilms in diabetic mice wounds. Furthermore, the nanocomposites were found to suppress proinflammatory cytokines, such as IL-1β, at the wound sites while regulating the expression of anti-inflammatory factors, including IL-10 and TGF-β1, throughout the recovery process. The presence of CuS/Qu-CNGs promoted angiogenesis, epithelialization, and collagen synthesis, thereby accelerating wound healing. Our developed CuS/Qu-CNGs nanocomposites have great potential in addressing the challenges associated with delayed wound healing caused by microbial pathogenesis.

Local contamination is a major cause of early deep wound infections following open posterior lumbosacral fusions

PURPOSE

Postoperative surgical site infection in patients treated with lumbosacral fusion has usually been thought to be caused by perioperative contamination. With the proximity of these incisions to the perineum, this study sought to determine if contamination by gastrointestinal and/or urogenital flora should be considered as a major cause of this complication.

METHODS

We conducted a retrospective review of adults treated with open posterior lumbosacral fusions between 2014 and 2021 to identify common factors in deep postoperative infection and the nature of the infecting organisms. Cases of tumor, primary infection and minimally invasive surgery were excluded.

RESULTS

489 eligible patients were identified, 20 of which required debridement deep to the fascia (4.1%). Mean age, operative time, estimated blood loss and levels fused were similar between both groups. The infected group had a significantly higher BMI. The mean time from primary procedure to debridement was 40.8 days. Four patients showed no growth, 3 showed Staphylococcus sp. infection (Perioperative Inside-Out) requiring debridement at 63.5 days. Thirteen showed infection with intestinal or urogenital pathogens (Postoperative Outside-In) requiring debridement at 20.0 days. Postoperative Outside-In infections led to debridement 80.3 days earlier than Perioperative Inside-Out infections (p = 0.007).

CONCLUSIONS

65% of deep infections in patients undergoing open lumbosacral fusion were due to early contamination by pathogens associated with the gastrointestinal and/or urogenital tracts. These required earlier debridement than Staphylococcus sp.

INFECTIONS

There should be renewed focus on keeping these pathogens away from the incision during the early stages of wound healing.

Box-Behnken design to optimize the cross-linked sodium alginate/mucilage/Aloe vera film: Physical and mechanical studies

The crosslinked sodium alginate/mucilage/Aloe vera/glycerin was optimized by different ratios of each factor to be an absorption wound dressing base for infected wound healing. Mucilage was extracted from seeds of Ocimum americanum. The Box-Behnken design (BBD) in response surface methodology (RSM) was used to construct an optimal wound dressing base with the target ranges of mechanical and physical properties of each formulation. The independent variables selected were sodium alginate (X1: 0.25-0.75 g), mucilage (X2: 0.00-0.30 g), Aloe vera (X3: 0.00-0.30 g), and glycerin (X4: 0.00-1.00 g). The dependent variables were tensile strength (Y1: low value), elongation at break (Y2: high value), Young's modulus (Y3: high value), swelling ratio (Y4: high value), erosion (Y5: low value), and moisture uptake (Y6: high value). The results showed that the wound dressing base with the most desirable response consists of sodium alginate (59.90 % w/w), mucilage (23.96 % w/w), and glycerin (16.14 % w/w) without Aloe vera gel powder (0.00 % w/w).

Enhancement of cell migration and wound healing by nano-herb ointment formulated with biosurfactant, silver nanoparticles and Tridax procumbens

Introduction

Ointments are generally used as a therapeutic agent for topical medication or transdermal drug delivery, such as wound healing and skin lesions.

Methods

In this study, Tridax procumbens plant extract (0.7 g/mL) was used to prepare herbal-infused oil as the oil phase and gelatin-stabilized silver nanoparticle (G-AgNPs) (0.3 g/mL) as the aqueous phase. To blend the oil and aqueous phases, rhamnolipid biosurfactant with a critical micelle concentration of 55 mg/L from strain Pseudomonas aeruginosa PP4 has been used for herb ointment preparation. The average size of the synthesized G-AgNPs was observed between 10-30 nm and confirmed as spherical-shaped particles by TEM analysis. Subsequently, GC-MS and FTIR characterization are used to confirm herb ointment's chemical and functional characteristics.

Results

Based on the antibacterial studies, the highest microbial growth inhibition was observed for herb ointment, about 19.5 mm for the pathogen Staphylococcus aureus at the concentration of 100 μg/mL, whereas 15.5 mm was obtained for Escherichia coli, respectively. In addition, the minimum inhibitory concentration (MIC) assay showed negligible bacterial growth at 100 μg/mL for S. aureus and E. coli, respectively. Moreover, the cell viability assay for herb ointment exhibited low cytotoxic activity at higher concentrations (100 μg/mL) in Vero cell lines. In this study, wound scratch assay showed a significant cell migration rate (90 ± 2%) in 3 days of incubation than the control (62 ± 2%).

Discussion

As a result, the biosurfactant-based nano-topical herb ointment revealed a low cytotoxic and higher cell migration capacity. Altogether, these findings highlighted the utility of this herb ointment in therapeutic applications such as wound healing.

Evidence-based management of keloids and hypertrophic scars in dermatology

While normal, controlled wound-healing results in scars that are nearly imperceptible, hypertrophic scars (HTS) and keloids are the result of an abnormal wound-healing process that can leave unsightly, difficult-to-treat lesions. While such scars are classically associated with surgical incisions, they may also result from burns or accidental trauma to the skin. Several different measures can be taken to prevent the formation of scars or treat those that have already formed. Prevention focuses on reducing inflammation during the wound-healing process, and minimizing tension in the lesion when appropriate. Treatments range from non-invasive modalities such as pressure therapy, topicals, and symptom management, to invasive methods such as injections, lasers, and even surgery. While some treatments, such as corticosteroid injections, have been used in the treatment of HTS and keloids for decades, other newer therapies have only been described in case reports or are still in early phases of clinical trials. Because optimal scar management will not be the same for every patient, further investigation of newer agents and methods is warranted and may benefit a great number of patients. This paper will review the evidence-based management of scars, including current widely used treatment options and promising newly emerging therapies.

Alginate-Based Materials Loaded with Nanoparticles in Wound Healing

Alginate is a naturally derived polysaccharide widely applied in drug delivery, as well as regenerative medicine, tissue engineering and wound care. Due to its excellent biocompatibility, low toxicity, and the ability to absorb a high amount of exudate, it is widely used in modern wound dressings. Numerous studies indicate that alginate applied in wound care can be enhanced with the incorporation of nanoparticles, revealing additional properties beneficial in the healing process. Among the most extensively explored materials, composite dressings with alginate loaded with antimicrobial inorganic nanoparticles can be mentioned. However, other types of nanoparticles with antibiotics, growth factors, and other active ingredients are also investigated. This review article focuses on the most recent findings regarding novel alginate-based materials loaded with nanoparticles and their applicability as wound dressings, with special attention paid to the materials of potential use in the treatment of chronic wounds.

Molecular hydrogen promotes wound healing by inducing early epidermal stem cell proliferation and extracellular matrix deposition

BACKGROUND

Despite progress in developing wound care strategies, there is currently no treatment that promotes the self-tissue repair capabilities. H₂ has been shown to effectively protect cells and tissues from oxidative and inflammatory damage. While comprehensive effects and how H₂ functions in wound healing remains unknown, especially for the link between H₂ and extracellular matrix (ECM) deposition and epidermal stem cells (EpSCs) activation.

METHODS

Here, we established a cutaneous aseptic wound model and applied a high concentration of H₂ (66% H₂) in a treatment chamber. Molecular mechanisms and the effects of healing were evaluated by gene functional enrichment analysis, digital spatial profiler analysis, blood perfusion/oxygen detection assay, in vitro tube formation assay, enzyme-linked immunosorbent assay, immunofluorescent staining, non-targeted metabonomic analysis, flow cytometry, transmission electron microscope, and live-cell imaging.

RESULTS

We revealed that a high concentration of H₂ (66% H₂) greatly increased the healing rate (3 times higher than the control group) on day 11 post-wounding. The effect was not dependent on O₂ or anti-reactive oxygen species functions. Histological and cellular experiments proved the fast re-epithelialization in the H₂ group. ECM components early (3 days post-wounding) deposition were found in the H₂ group of the proximal wound, especially for the dermal col-I, epidermal col-III, and dermis-epidermis-junction col-XVII. H₂ accelerated early autologous EpSCs proliferation (1-2 days in advance) and then differentiation into myoepithelial cells. These epidermal myoepithelial cells could further contribute to ECM deposition. Other beneficial outcomes include sustained moist healing, greater vascularization, less T-helper-1 and T-helper-17 cell-related systemic inflammation, and better tissue remodelling.

CONCLUSION

We have discovered a novel pattern of wound healing induced by molecular hydrogen treatment. This is the first time to reveal the direct link between H₂ and ECM deposition and EpSCs activation. These H₂-induced multiple advantages in healing may be related to the enhancement of cell viability in various cells and the maintenance of mitochondrial functions at a basic level in the biological processes of life.

Recent Advances in Biodegradable Polymers and Their Biological Applications: A Brief Review

The rising significance of the field of biopolymers has driven the rapid progress of this distinctive class of polymeric materials in the past decades. Biodegradable polymers have acquired much attention because they play an essential role in humans' lives due to their specific tunable electrical conductivity and biodegradability characteristics, making them fascinating in many applications. Herein, we debated the recent progress in developing biodegradable polymers and their applications. Initially, we introduce the basics of conducting and biodegradable polymers, trailed by debates about the effective strategies currently used to develop biopolymers. Special importance will focus on the uses of biodegradable polymers in drug delivery and tissue engineering, as well as wound healing, demonstrating the recent findings, and uses of several biodegradable polymers in modern biological uses. In this review, we have provided comprehensive viewpoints on the latest progress of the challenges and future prospects involving biodegradable polymers' advancement and commercial applications.

Public Knowledge About How Common Chronic Diseases Affect Wound Healing Postoperatively in Aseer Region

Background

Wound healing has classically been described to occur in three phases, regardless of the mechanism of injury. These phases are the inflammatory, proliferative, and remodeling phases. Chronic diseases adversely affect the wound healing process, and more needs to be done for different policies, such as adjustment of drug therapy, diet, or behavior to help rapid wound healing. Diabetes, auto-immune diseases, obesity, malnutrition, cardiovascular disease, chronic renal disease, and cancers are the frequent co-morbidities affecting wound healing.

Aim

To assess the public knowledge about how common chronic diseases affect wound healing postoperatively in Aseer Region.

Methodology

A descriptive cross-sectional study targeting the general population living in the Aseer region for at least a year. Data were collected using a pre-structured electronic questionnaire initiated by the researchers after an intense literature review and experts’ consultation. The study questionnaire covered participants’ data, smoking and medical history, surgical history, and participant knowledge items. A questionnaire was used as a digital survey and distributed to all participants in a private and anonymous process.

Results

A total of 502 participants completed the study questionnaire. Participants' ages ranged from 18 to 60 years, with a mean age of 34.6 ± 12.9 years old. A total of 294 (58.6%) participants were males, and 341 (67.9%) were university graduates. Exact 430 (85.7%) know that Supervision and control of Diabetes Mellitus help in wound healing, 369 (73.5%) reported that Chronic diseases delay wound healing, and 449 (89.4%) think that commitment to therapeutic and preventive plans before and after any surgical procedure contributing in rapid wound healing for chronic diseases patients. As for the effect of chronic diseases on a surgical wound, 320 (63.7%) reported delayed wound healing, 241 (48%) knew it may increase the infection, and 186 (37.1%) reported it might Decrease blood supply to the site of a wound.

Conclusions

In conclusion, the study revealed that more than half of the population in Aseer regions were knowledgeable regarding the effect of chronic diseases on post-optative wound healing, especially for the benefit of a commitment to therapeutic and preventive plans before and after any surgical procedure.

Fibroblasts Close a Void in Free Space by a Purse-String Mechanism

The mechanism by which stromal cells fill voids in injured tissue remains a fundamental question in regenerative medicine. While it is well-established that fibroblasts fill voids by depositing extracellular matrix (ECM) proteins as they migrate toward the wound site, little is known about their ability to adopt an epithelial-like purse-string behavior. To investigate fibroblast behavior during gap closure, we created an artificial wound with a large void space. We discovered that fibroblasts could form a free-standing bridge over deep microvoids, closing the void via purse-string contraction, a mechanism previously thought to be unique to epithelial wound closure. The findings also revealed that myosin II mediated contractility and intercellular adherent junctions were required for the closure of the fibroblast gap in our fabricated three-dimensional artificial wound. To fulfill their repair function under the specific microenvironmental conditions of wounds, fibroblasts appeared to acquire the structural features of epithelial cells, namely, contractile actin bundles that span over multiple cells along the boundary. These findings shed light on a novel mechanism by which stromal cells bridge the 3D gap during physiological processes such as morphogenesis and wound healing.

Autophagy Plays Multiple Roles in the Soft-Tissue Healing and Osseointegration in Dental Implant Surgery-A Narrative Review

Dental endo-osseous implants have become a widely used treatment for replacing missing teeth. Dental implants are placed into a surgically created osteotomy in alveolar bone, the healing of the soft tissue lesion and the osseointegration of the implant being key elements to long-term success. Autophagy is considered the major intracellular degradation system, playing important roles in various cellular processes involved in dental implant integration. The aim of this review is an exploration of autophagy roles in the main cell types involved in the healing and remodeling of soft tissue lesions and implant osseointegration, post-implant surgery. We have focused on the autophagy pathway in macrophages, endothelial cells; osteoclasts, osteoblasts; fibroblasts, myofibroblasts and keratinocytes. In macrophages, autophagy modulates innate and adaptive immune responses playing a key role in osteo-immunity. Autophagy induction in endothelial cells promotes apoptosis resistance, cell survival, and protection against oxidative stress damage. The autophagic machinery is also involved in transporting stromal vesicles containing mineralization-related factors to the extracellular matrix and regulating osteoblasts' functions. Alveolar bone remodeling is achieved by immune cells differentiation into osteoclasts; autophagy plays an important and active role in this process. Autophagy downregulation in fibroblasts induces apoptosis, leading to better wound healing by improving excessive deposition of extracellular matrix and inhibiting fibrosis progression. Autophagy seems to be a dual actor on the scene of dental implant surgery, imposing further research in order to completely reveal its positive features which may be essential for clinical efficacy.

Assessment of Bacterial Nanocellulose Loaded with Acetylsalicylic Acid or Povidone-Iodine as Bioactive Dressings for Skin and Soft Tissue Infections

Bacterial nanocellulose (BNC) is a novel nanomaterial known for its large surface area, biocompatibility, and non-toxicity. BNC contributes to regenerative processes in the skin but lacks antimicrobial and anti-inflammatory properties. Herein, the development of bioactive wound dressings by loading antibacterial povidone-iodine (PVI) or anti-inflammatory acetylsalicylic acid (ASA) into bacterial cellulose is presented. BNC is produced using Hestrin-Schramm culture media and loaded via immersion in PVI and ASA. Through scanning electron microscopy, BNC reveals open porosity where the bioactive compounds are loaded; the mechanical tests show that the dressing prevents mechanical wear. The loading kinetic and release assays (using the Franz cell method) under simulated fluids present a maximum loading of 589.36 mg PVI/g BNC and 38.61 mg ASA/g BNC, and both systems present a slow release profile at 24 h. Through histology, the complete diffusion of the bioactive compounds is observed across the layers of porcine skin. Finally, in the antimicrobial experiment, BNC/PVI produced an inhibition halo for Gram-positive and Gram-negative bacteria, confirming the antibacterial activity. Meanwhile, the protein denaturation test shows effective anti-inflammatory activity in BNC/ASA dressings. Accordingly, BNC is a suitable platform for the development of bioactive wound dressings, particularly those with antibacterial and anti-inflammatory properties.

Bilayer Hydrogels for Wound Dressing and Tissue Engineering

A large number of different skin diseases such as hits, acute, and chronic wounds dictate the search for alternative and effective treatment options. The wound healing process requires a complex approach, the key step of which is the choice of a dressing with controlled properties. Hydrogel-based scaffolds can serve as a unique class of wound dressings. Presented on the commercial market, hydrogel wound dressings are not found among proposals for specific cases and have a number of disadvantages—toxicity, allergenicity, and mechanical instability. Bilayer dressings are attracting great attention, which can be combined with multifunctional properties, high criteria for an ideal wound dressing (antimicrobial properties, adhesion and hemostasis, anti-inflammatory and antioxidant effects), drug delivery, self-healing, stimulus manifestation, and conductivity, depending on the preparation and purpose. In addition, advances in stem cell biology and biomaterials have enabled the design of hydrogel materials for skin tissue engineering. To improve the heterogeneity of the cell environment, it is possible to use two-layer functional gradient hydrogels. This review summarizes the methods and application advantages of bilayer dressings in wound treatment and skin tissue regeneration. Bilayered hydrogels based on natural as well as synthetic polymers are presented. The results of the in vitro and in vivo experiments and drug release are also discussed.

Molecular Targets of Pinocembrin Underlying Its Regenerative Activities in Human Keratinocytes

Pinocembrin is one of the well-known compounds in the group of flavonoids. The pharmacological activities of pinocembrin in association with wound-healing activities have been reported. However, its effects on the aspect of cellular interaction underlying growth and survival are still unidentified in human keratinocytes. Our previous study reported that Boesenbergia rotunda potently stimulated survival and proliferation of a human keratinocyte cell line (HaCaT). On the basis that pinocembrin is revealed to be one of the major constituents of this plant, we aimed to define the survival- and proliferation-enhancing effects of this compound at the cellular level. Results from the current study confirmed that pinocembrin induced an increase in HaCaT cell number. At the signaling perspective, we identified that pinocembrin significantly triggered ERK1/2 and Akt activation. The stimulating effects of pinocembrin were clearly inhibited by MEK and PI3K inhibitors authenticating that proliferation- and survival-promoting activities of pinocembrin were mainly acted on these two signaling cascades. Altogether, we successfully identified that pinocembrin functions to induce keratinocyte proliferation and survival, at least by provoking MAPK and PI3K pathways. Our study encourages the fact that pinocembrin is one of the interesting natural flavonoid compounds to be developed as a wound closure-promoting agent.

Smartphone-based wound dressings: A mini-review

In spite of remarkable progress in the field of wound curation, treatment of chronic wounds remains a challenge for medical services. The constant rise in the number of patients with chronic wounds and their related financial burden has caused concern for the healthcare system. The complicated and dynamic nature of chronic wounds has increased the curation time and difficulty of wound healing with conventional bandages. Efficient healing of these wounds requires new bandages with the ability of real-time monitoring, data analysis, and drug delivery, which protect the wound against infection and accelerate the treatment process. The recent development of smartphone applications and digital equipment in medicine provides an opportunity for significant improvement in wound care through the incorporation of “smart” technologies into clinical practice. The focus of this review is to provide an overview of the current status of smartphones and digital technology in the management of wounds.

Chronic Inflammation in Non-Healing Skin Wounds and Promising Natural Bioactive Compounds Treatment

Chronic inflammation is one of the hallmarks of chronic wounds and is tightly coupled to immune regulation. The dysregulation of the immune system leads to continuing inflammation and impaired wound healing and, subsequently, to chronic skin wounds. In this review, we discuss the role of the immune system, the involvement of inflammatory mediators and reactive oxygen species, the complication of bacterial infections in chronic wound healing, and the still-underexplored potential of natural bioactive compounds in wound treatment. We focus on natural compounds with antioxidant, anti-inflammatory, and antibacterial activities and their mechanisms of action, as well as on recent wound treatments and therapeutic advancements capitalizing on nanotechnology or new biomaterial platforms.

In Vitro Direct and Indirect Cytotoxicity Comparative Analysis of One Pre-Hydrated versus One Dried Acellular Porcine Dermal Matrix

Aim: The aim of the present study was to compare the direct and indirect cytotoxicity of a porcine dried acellular dermal matrix (PDADM) versus a porcine hydrated acellular dermal matrix (PHADM) in vitro. Both are used for periodontal and peri-implant soft tissue regeneration. Materials and methods: Two standard direct cytotoxicity tests—namely, the Trypan exclusion method (TEM) and the reagent WST-1 test (4-3-[4-iodophenyl]-2-[4-nitrophenyl]-2H-[5-tetrazolio]-1,3-benzol-desulphonated)—were performed using human primary mesenchymal stem cells (HPMSCs) seeded directly onto a PDADM and PHADM after seven days. Two standard indirect cytotoxicity tests—namely, lactate dehydrogenase (LTT) and MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazoliumbromide)—were performed using HPMSCs cultivated in eluates from the matrices incubated for 0.16 h (10 min), 1 h, and 24 h in a serum-free cell culture medium. Results: The WST and the TEM tests revealed significantly lower direct cytotoxicity values of HPMSCs on the PHADM compared with the PDADM. The indirect cytotoxicity levels were low for both the PHADM and PDADM, peaking in short-term eluates and decreasing with longer incubation times. However, they were lower for the PHADM with a statistically significant difference (p < 0.005). Conclusions: The results of the current study demonstrated a different biologic behavior between the PHADM and the PDADM, with the hydrated form showing a lower direct and indirect cytotoxicity.

Design and development of thyroxine/heparin releasing affordable cotton dressings to treat chronic wounds

This research on a thyroxine/heparin-based cotton wound dressing tests angiogenic and wound healing ability of thyroxine/heparin in a chick chorionic allantoic membrane bioassay and in skin wounds in healthy rats. Commercially available cotton dressings were simply loaded with thyroxine/heparin solutions and coated with wax. Prior to undertaking the animal study, we assessed in vitro release of thyroxine/heparin from coated and uncoated cotton dressings. Both showed more than 85% release of drug over 14 days, though the lesser release was observed in wax-coated thyroxine/heparin dressing as compared to uncoated thyroxine/heparin dressing. Testing of angiogenesis through CAM assay proved good angiogenic potential of heparin and thyroxin, but the thyroxine found more angiogenic than heparin. In animal study, full-thickness skin wounds of 20 mm diameter showed good healing in both heparin and thyroxine-treated groups. But the most striking result was seen in the thyroxine-treated group where thyroxine showed significant difference with heparin-treated group and completely healed the wounds in 23 days. Thus, the study suggest that thyroxine possesses greater angiogenic and wound healing potential than heparin, and the use of thyroxine/heparin-loaded wax-coated cotton dressing could be a cost-effective option for the management of chronic wounds.

Development and Characterization of Multifunctional Wound Dressing with the Property of Anti-bacteria and Angiogenesis

Overcoming the bacterial infection and promoting angiogenesis are challenge and imperious demands in wound healing and skin regeneration. Hereby, we developed a multifunctional AMP/S1P@PLA/gelatin wound dressing fabricated by electrospinning poly (L-lactic acid) (PLA)/gelatin with antimicrobial polypeptides (AMPs) and sphingosine-1-phosphate (S1P) in order to inhibit the bacteria growth and induce angiogenesis. In our work, AMP/S1P@PLA/gelatin wound dressing was obtained by two-step method of electrospinning and dopamine adsorption. Our results showed that incorporating AMP into PLA/gelatin nanofibrous membranes significantly improved antibacterial properties against both Escherichia coli and Staphylococcus aureus. S1P releasing from AMP/S1P@PLA/gelatin nanofibrous membranes could significantly enhance tube formation. Simultaneously, we found that the AMP/S1P@PLA/gelatin nanofibrous membranes facilitated the adhesion, proliferation, and migration of human umbilical vein endothelial cells (HUVECs) and murine fibroblast (L929). AMP/S1P@PLA/gelatin membranes could also accelerate infected wound healing and skin regeneration by antibacterial and pro-angiogenesis effects. In summary, our developed AMP/S1P@PLA/gelatin nanofibrous membranes could be multifunctional dressing for infected wound healing and skin regeneration. Schematic figure to describe the characterizations and preparation of AMP/S1P@PLA/gelatin nanofibrous membranes.

Production of alginate films containing Hypericum perforatum extract as an antibacterial and antioxidant wound dressing material

The incorporation of herbal extracts in wound dressing materials is an important concept that has been researched recently. In this study, alginate films incorporated in the various ratio (0.25–1% v/v) of Hypericum perforatum extract (HPE) for potential applications of wound dressing were successfully prepared by solvent-casting method. The obtained films were examined for cytotoxicity, in vitro wound healing potential, swelling behavior, antioxidant, and antibacterial properties. When compared to the alginate film (Al) alone, HPE incorporated alginate films (HPE/Al) exhibit improved antioxidant properties according to the results of CUPRAC assay and antioxidant activity increases with the rate of HPE. Also, HPE/Al films exhibited antibacterial activity against E. coli and S. aureus, and addition with the HPE extract into films significantly increased the antibacterial activity against S. aureus. All film samples had no cytotoxic effects on fibroblast cell line and HPE/Al films showed a proliferative effect with high extract concentrations (1%) compared to extract free-films. Also, scratch assay results show that films containing 0.5% (v/v) HPE may have a positive effect on wound healing. The results have shown that the newly developed HPE incorporated alginate films are a candidate as antibacterial, and antioxidant wound dressing for use on burn or excision wounds.

Intracellular glucose starvation affects gingival homeostasis and autophagy

Human gingival fibroblasts (HGnFs) maintain periodontal tissue homeostasis through active proliferation and migration. Clinically, it is considered that the wound-healing ability of the gingival tissue is maintained even in environments with insufficient supply of nutrients, such as glucose, immediately after periodontal surgery. However, the effects of such glucose-deficient environments on HGnFs remain unclear. This study aimed to investigate the effects of low-glucose environment on HGnFs homeostasis. We evaluated gingival wound healing by examining cell proliferation and migration and collagen synthesis in HGnFs cultured in 100, 50, 25, and 0 mg/dL glucose in vitro. The cellular stress levels were determined by measuring the lactate dehydrogenase (LDH) and reactive oxygen species (ROS) levels. The glucose metabolism of HGnFs in the low-glucose concentrations was studied by measuring glucose transporter type 1 (GLUT1) mRNA expression, glucose uptake assays, lactate and ATP productions. Molecular effects were examined with a focus on the LKB1-AMPK signaling pathway. Autophagy activity in glucose-deprived HGnFs was evaluated by measuring the levels of autophagy-related proteins. Low glucose levels increased cellular stress levels, autophagy activity, and enhanced glucose metabolism through the LKB1-AMPK signaling pathway, providing more ATPs to promote wound healing. Our results regarding glucose transfer suggest the rapid healing of gingival wounds.

Development and evaluation of drug delivery patch for topical wound healing application

Wound treatment remains a challenge to many clinicians because of the complexities of the wound healing process. With the astonishing progress of biomedical engineering during the past few decades, conventional drug delivery systems have been evolved into smart drug delivery systems with stimuli-responsive characteristics. The objective of this study was to develop and evaluate an electromechanically actuated drug dispensation device which can release active pharmaceutical compound in a controlled fashion. Additive manufacturing was employed to design and fabricate the device. Haptic technology was used to provide stimulation for drug release, and Cicatrin was used to evaluate the drug release patterns of device. Drug release study was comprised of in vitro drug release, static study, and the purpose of this study was to develop a compliance chart for different wound conditions. The effectiveness of shortlisted drug regimen from compliance chart was validated through microbial study and animal studies. The results of animal studies were compared with commercially available drug release systems. The results of drug release studies gave different dose regimens for different wound conditions. The effective dose regimen was able to create 1-cm-wide microbial zone of inhibitions. The wound healing rate of mice for commercially available release system for five consecutive days was 10%, 10%, 20%, 40% and 50% and for test device was 10%, 30%, 60%, 90% and 100%. Hence, the device proved its effectiveness and efficacy of dosage regimen for wound healing applications through in vitro, microbial and in vivo studies. In conclusion, this device proved to be an accurate and specific drug delivery system with improved medication and therapeutic outcomes for personalized medication.

Combination Therapy of Metadichol Nanogel and Lipocalin-2 Engineered Mesenchymal Stem Cells Improve Wound Healing in Rat Model of Excision Injury

Purpose: Currently, several disorders including burns, trauma, excisional and diabetic wounds, and bedsores threaten the human health. Application of mesenchymal stem cells (MSCs) is recommended for treatment of skin disorders. However, because of oxidative stress and inflammation after skin injury, survival of transplanted MSCs is low which in turn negatively affects the efficiency of the MSCs-based therapy. In an attempt to address the aforementioned challenge and introducing a novel potential therapeutic strategy, we employed combination therapy by lipocalin 2 (Lcn2)-engineered MSCs and a Metadichol (an inverse agonist of vitamin D receptor (VDR)) nanogel in a rat model of excisional wound.

Methods: First, human umbilical cord MSCs (hUC-MSCs) was transfected by a recombinant plasmid encoding Lcn2 gene. Next, a combination of Metadichol nanogel and the engineered MSCs was co-applied on wound in rat model of excision injury. Finally the improvement of wound healing in experimental groups was evaluated by photography and histological assessments (hematoxylin and eosin staining).

Results: Our findings revealed that the repair rate was higher in the group received combination therapy comparing to control groups. Notably, Metadichol+Lcn2-MSCs showed significantly higher wound contraction rate compared to control group at all time points (P value < 0.001). Furthermore, wound repair rate was 95% 14 days after surgery, and 100% after 21 days in the treatment groups. Our results also revealed that the combination therapy improved and accelerated the wound healing process.

Conclusion: Our findings suggest a novel potential therapeutic strategy i.e. Lcn2-engineered MSCs and Metadichol for wound healing. However, further preclinical and clinical studies are required.

Microencapsulated rhEGF to facilitate epithelial healing and prevent scar formation of cesarean wound: A randomized controlled trial

OBJECTIVE

Cesarean section (CS) is a major surgical intervention that affects women at childbearing age. Scarring from CS potentially causes discomfort and psychological distress. Emerging evidence indicates that epidermal growth factor (EGF) plays crucial roles in wound healing with the potential of minimizing scar formation. This study aims to investigate the effect of microencapsulated recombinant human EGF (Me-EGF) in scar prevention. Silicone gel was incorporated as part of the routine scar treatment.

MATERIALS AND METHODS

Healthy women scheduled for cesarean delivery were enrolled and randomized to three groups: (1) no scar treatment, (2) silicone gel only, or (3) silicone gel plus Me-EGF. Vancouver Scar Scale (VSS: vascularity, pigmentation, elasticity, and height) was used for scar assessment at the 6th month and 9th month after CS.

RESULTS

A total of 60 women were enrolled, but one patient withdrew due to noncompliance with the follow-up visit requirement. Me-EGF-containing treatment group consistently scored the lowest on every parameter in the VSS scale, followed by silicone gel group, and the group with no scar treatment. Kruskal-Wallis tests indicated significant differences (p < 0.05) between Me-EGF-containing treatment group and the other two groups in vascularity, pigmentation, elasticity, and the VSS total score, at either 6th month, 9th month, or both time points. The only parameter not showing any significant between-group difference was scar height, but the pattern still remained the same, in which Me-EGF group scored better in both month 6 and 9.

CONCLUSION

Surgical incisions in lower abdomen posed challenge in scar management. Our findings suggest that Me-EGF is a potential therapeutic option for better wound healing and scar prevention.

Multi-functional effects of a nitric oxide-conjugated copolymer for accelerating palatal wound healing

The damaged site of a palatal wound is difficult to repair and often remains unclosed due to failure of the healing process, which occurs in inadequate environments of the oral cavity. Nitric oxide (NO) has effective functions in repairing damaged tissues, but it has a limitation due to short lifetime and rapid diffusion. Here, we synthesize a donor to deliver exogenous NO gas and verify its therapeutic effect for the palatal wound healing, which is known to take longer for healing due to the poor environment of warm saliva containing millions of microbes. NO was incorporated into the synthetic polymer and the NO-donors were characterized based upon their ability to release NO. The NO donor not only reduced cytotoxicity but also increased migration and proliferation in gingival fibroblasts. Moreover, the angiogenic capacity was improved by NO-donor treatment. In the palatal wound model, the NO-treatment was involved in enhancing the biological responses associated with wound healing. This strategy suggests that treatment involving controlled NO release may have beneficial effects on palatal wound healing.

Medicinal plants and their components for wound healing applications

Background

Wound is an anatomical and functional disruption of the skin following an injury. In response to the injury, wound healing is a complex process of tissue repair or remodeling. Historically, plants and plant-based constituents have been extensively used for the treatment and management of different types of wounds. In the current times, different types of biopolymers are being researched for developing economical, sustainable, stable, and effective delivery system for the treatment of wounds.

Main text

The present review article attempts to enlist medicinal plants which have been reported to be effective in the treatment of wounds. Plant constituent-based wound dressings have also been discussed systematically including patented formulations reported by different inventors.

Conclusion

The compiled data aims to update the researchers/scientists which will be helpful in providing them a directional view in understanding the role and importance of plant-based components for the treatment and management of wounds.

Orabase Promotes Oral Epithelization in a Wound Healing Rat Model: An Immunohistochemical Study

BACKGROUND

Recent evidence suggests that bone marrow-derived stem cells may have an important role in the natural process of wound healing. The aim of the present study was to examine the effect of orabase paste application on primary wound healing in a palatal rat model.

MATERIALS AND METHODS

A total of 48 six-month-old male Wistar rats weighting 427 to 650 g were included. A mid-crestal incision was made on the maxillary alveolar ridge. A full-thickness flap was raised on either side of the incision and was then repositioned and sutured. Three experimental groups were used: O-study group-orabase, N-negative control group, and I-intact control group. Half of the animals were killed on 7 days and the remaining on 14 days postoperatively. Outcome parameters included epithelial gap; inflammatory infiltration; expression of stem cell markers within the oral epithelium and stromal cells; and physical properties of stromal collagen fibers and myofibroblasts. Investigations were performed at 2 time points (7 and 14 d) during the wound healing process.

RESULTS

The epithelial gap closed completely after 7 days in the O group versus 14 days or more in the N group. The inflammatory reaction was relatively low and not significantly different between groups O and N. Orabase upregulated the expression of CK14, CK15, and epithelial SOX2. Connective tissue SOX2, CD34, and α-smooth muscle actin and physical properties of stromal collagen fibers were not influenced by the application of orabase.

CONCLUSIONS

Orabase promotes epithelial gap closure in a primary wound healing model in rats. The effect is exerted through promotion of epithelial differentiation from stem cells.

Biological properties of copper-doped biomaterials for orthopedic applications: A review of antibacterial, angiogenic and osteogenic aspects

Copper is an essential trace element required for human life, and is involved in several physiological mechanisms. Today researchers have found and confirmed that Cu has biological properties which are particularly useful for orthopedic biomaterials applications such as implant coatings or biodegradable filler bone substitutes. Indeed, Cu exhibits antibacterial functions, provides angiogenic ability and favors osteogenesis; these represent major key points for ideal biomaterial integration and the healing process that follows. The antibacterial performances of copper-doped biomaterials present an interesting alternative to the massive use of prophylactic antibiotics and help to limit the development of antibiotic resistance. By stimulating blood vessel growth and new bone formation, copper contributes to the improved bio-integration of biomaterials. This review describes the bio-functional advantages offered by Cu and focuses on the antibacterial, angiogenic and osteogenic properties of Cu-doped biomaterials with potential for orthopedic applications.

Comparison of the Effect of Adipocyte-derived Stem Cells and Curcumin Nanoliposomes with Phenytoin on Open Cutaneous Wound Healing in Rats

BACKGROUND

Reducing the healing time of wounds can decrease the patient&#039;s immobility time and their medical costs, leading a faster return of the patients to daily work.

OBJECTIVE

The aim of the present study is to compare the effect of adipose-derived stem cells and curcumin- containing liposomal nanoparticles with phenytoin on wound healing.

METHODS

After anesthesia of the rats, open skin ulcers were made by a bistoury blade. Subsequently, stem cells were removed from the adipose tissue of the upper border of the epididymis. The originality of stem cells was then confirmed by the flow cytometry. The fusion method was used to prepare the liposome; and also, nanoliposomal particles were confirmed by using the DLS microscope. The percentage of recovery and the cell count was measured with IMAGEJ. The expression of genes was assessed by PCR. The number of fibroblasts was counted by immunohistochemistry techniques. The amount of collagen was determined by Tri-chromosome staining, and the number of capillaries was enumerated by H &amp; E staining.

RESULTS

The expression of the TGF-&#946;1 gene, vascular number, wound healing rate and the number of fibroblasts increased significantly in adipose tissue-derived stem cells and curcumin nanoliposome groups (p&lt;0.05); the wound surface was also decreased significantly (p&lt;0.05).

CONCLUSION

Based on the results of our research, adipose tissue-derived stem cells and curcumin nanoliposomes can heal wounds efficiently.

Effect of gallium maltolate on a model of chronic, infected equine distal limb wounds

Distal limb wounds are common injuries sustained by horses and their healing is fraught with complications due to equine anatomy, prevalence of infection, and challenges associated with wound management. Gallium is a semi-metallic element that has been shown to possess antimicrobial properties and aid in wound healing in various preclinical models. The effects of Gallium have not been studied in equine wound healing. Therefore, the objective of this study was to compare healing rates between gallium-treated and untreated wounds of equine distal limbs and to demonstrate the antimicrobial effects of gallium on wounds inoculated with S. aureus. Using an established model of equine wound healing we demonstrated beneficial effects of 0.5% topical gallium maltolate on equine wound healing. Specifically we documented reduced healing times, reduced bioburden, and reduced formation of exuberant granulation tissue in wounds treated with gallium maltolate as compared with untreated wounds. Gallium appeared to exert its beneficial effects via its well-described antimicrobial actions as well as by altering the expression of specific genes known to be involved in wound healing of horses and other animals. Specifically, gallium maltolate appeared to increase expression of transforming growth factor-β in both infected and un-infected wounds. Further work is needed to document the effects of gallium on naturally occurring equine wounds and to compare the effects of gallium with other wound treatment options. These data, however, suggest that gallium may be an attractive and novel means of improving equine distal limb wound healing.

A Systematic Review on Classification, Identification, and Healing Process of Burn Wound Healing

Because of the intrinsic complexity, the classification of wounds is important for the diagnosis, management, and choosing the correct treatment based on wound type. Generally, burn injuries are classified as a class of wounds in which injury is caused by heat, cold, electricity, chemicals, friction, or radiation. On the other hand, wound healing is a complex process, and understanding the biological trend of this process and differences in the healing process of different wounds could reduce the possible risk in many cases and greatly reduce the future damage to the injured tissue and other organs. The aim of this review is to provide a general perspective for the burn wound location among the other types of injuries and summarizing as well as highlighting the differences of these types of wounds with emphasizing on factors affecting thereof.

Effect of Cord Blood Platelet Gel on wound healing capacity of human Mesenchymal Stromal Cells

BACKGROUND

Wound healing is a dynamic process, involving the recruitment of growth factors, cytokines, chemokines and cellular populations. Recently, the Cord Blood Platelet Gel (CBPG) has been applied successfully in wound closure and tissue regeneration. Moreover, its proper combination with stem cell populations such as Mesenchymal Stromal Cells (MSCs) may positively improve the wound healing process. Based on the above data, this study aimed to the evaluation of wound healing capacity of MSCs combined with CBPG under in vitro conditions.

METHODS

Initially, CBPG was developed from Cord Blood Units (CBUs). The determination of wound healing ability of MSCs was performed using the scratch wound assay. In addition, the morphological features, immunophenotypical characteristics and differentiation capacity of MSCs were evaluated.

RESULTS

Scratch wound assay results showed, that CBPG could positively stimulate the MSCs migration. Moreover, MSCs cultured in presence of CBPG were characterized by elongated shape and improved stemness properties as it was indicated by flow cytometric analysis and differentiation process.

CONCLUSION

These results clearly showed the beneficial effect of CBPG in combination with MSCs in wound healing. The proper combination of CBPG with stem cells strategy may enhance the healing process in patients with skin erosions.

Biological characterization of dehydrated amniotic membrane allograft: Mechanisms of action and implications for wound care

There is a growing clinical demand in the wound care market to treat chronic wounds such as diabetic foot ulcers. Advanced cell and tissue-based products (CTPs) are often used to address challenging chronic wounds where healing has stalled. These products contain active biologics such as growth factors and cytokines as well as structural components that support and stimulate cell growth and assist in tissue regeneration. This study addresses the in vitro biologic effects of a clinically available dehydrated amniotic membrane allograft (DAMA). The broad mechanism of action results from DAMA's biologic composition that leads to stimulation of cell migration cell proliferation, and reduction of pro-inflammatory cytokines. Results show that DAMA possesses growth factors and cytokines such as EGF, FGF, PDGFs, VEGF, TGF-β, IL-8, and TIMPs 1 and 2. Furthermore, in vitro experiments demonstrate that DAMA stimulates cell proliferation, cell migration, secretion of collagen type I, and the reduction of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. This study findings are consistent with the clinical benefits previously published for DAMA and other CTPs in chronic wounds suggesting that the introduction of DAMA to non-healing, complex wounds helps to improve the wound milieu by providing essential structural components, cytokines, and growth factors to create an appropriate environment for wound healing.

Palatal Wound Healing with Primary Intention in a Rat Model-Histology and Immunohistomorphometry

Background and objectives: Subepithelial connective tissue graft (SCTG) from the palate has been considered as the “gold standard” for the treatment of deep gingival recessions. A single-incision technique was reported to allow primary wound healing. A palatal single incision was performed in a rat model. The present study assessed the histology and histomorphometry of palatal wound healing following surgical closure with primary intention. Materials and Methods: Twenty-six 6-month-old male Wistar rats weighing 427–650 g. An incision was made on the maxillary palate. A full thickness flap was raised palatally, and then repositioned and sutured. Two experimental groups: S—Study group, I—Intact control group. Half of the animals were sacrificed 7 days and the remaining 14 days postoperatively. Outcome parameters included—epithelial gap; inflammatory infiltration; vascular fraction, expression of myofibroblasts and stem cell markers within the oral epithelium and stromal cells and physical properties of stromal collagen fibers. Investigations were performed at two time-points (7 and 14 days) during the wound healing process. Results: The epithelial gap closed completely after 14 days. The inflammatory reaction and vascular fraction were relatively low. Surgical trauma downregulated the expression of cytokeratin (CK) 14 and CK 15, which returned to normal after 14 days. Epithelial differentiation was mediated through upregulation of connective tissue sex- determining-region-Y-box2 (SOX2). Epithelial SOX2, CD34, alpha smooth muscle actin (αSMA) and physical properties of stromal collagen fibers were not influenced by the surgical trauma. Conclusions: Surgical trauma followed by palatal wound healing with primary intention in a rat model heals within 14 days. It induces minimal inflammatory infiltration and vascular proliferation. Epithelization is exerted through promotion of epithelial differentiation from stem cells by connective tissue SOX2.

Preparation and characterization of carboxymethyl chitosan/collagen peptide/oxidized konjac composite hydrogel

Medical dressings are used to protect damaged skin from external factors and provide a good healing environment. Hydrogels are aggregates of hydrophilic polymers and water that have a three-dimensional space and can absorb large amounts of water. It has been widely studied in the field of biomedical materials. In this study, we prepared a novel composite hydrogel combined carboxymethyl chitosan, collagen peptide and oxidized konjac, all three materials have been shown to be biocompatible. Then, we set up different hydrogels and tested hydrogels with different proportions. The structures of CMCS (carboxymethyl chitosan)/COP (collagen peptide)/OKGM (oxidized konjac) hydrogels were characterized by IR, NMR, X-ray diffraction and SEM. The effects of hydrogels on the growth of NS-FB and HS-FB cells were studied in vitro. The results of these tests show that the composite hydrogel has excellent mechanical properties and biological activity, and has potential application in wound dressing field.

Investigation of surgical technique for bronchial stump closure after lobectomy in animal model

OBJECTIVE

Bronchial fistulae following lung surgery are associated with high mortality. We examined the histological effects of mucosal ablation as a technique for closing bronchial stumps to prevent bronchial fistulae in an animal model.

METHODS

Left lower lobectomy was performed in beagles under general anesthesia. The bronchial stumps were closed using one of the following four methods: (A) manual suturing using 3-0 absorbable sutures, (B) ablation of bronchial mucosa with electric cautery and manual sutures, (C) stapling and reinforcement with manual sutures, or (D) ablation and stapling followed by reinforcement with manual sutures. Bronchial stumps were histologically evaluated on postoperative day 14.

RESULTS

No bronchial fistulae were noted in the animals during the observation period. Histologically, there were no adhesions between the bronchial mucosae at the suture and staple lesions in groups A and C. The bronchial mucosae were adherent at the ablation sites in groups B and D. Inflammatory cells, myofibroblasts, and neovascular vessels were abundant around the ablated lesions.

CONCLUSIONS

Bronchial mucosal ablation may play a key role in mucosal adhesion and tight union of the bronchial stump.

Stem cell therapy for chronic skin wounds in the era of personalized medicine: From bench to bedside

With the significant financial burden of chronic cutaneous wounds on the healthcare system, not to the personal burden mention on those individuals afflicted, it has become increasingly essential to improve our clinical treatments. This requires the translation of the most recent benchtop approaches to clinical wound repair as our current treatment modalities have proven insufficient. The most promising potential treatment options rely on stem cell-based therapies. Stem cell proliferation and signaling play crucial roles in every phase of the wound healing process and chronic wounds are often associated with impaired stem cell function. Clinical approaches involving stem cells could thus be utilized in some cases to improve a body's inhibited healing capacity. We aim to present the laboratory research behind the mechanisms and effects of this technology as well as current clinical trials which showcase their therapeutic potential. Given the current problems and complications presented by chronic wounds, we hope to show that developing the clinical applications of stem cell therapies is the rational next step in improving wound care.

Effects of Bilayer Nanofibrous Scaffolds Containing Curcumin/Lithospermi Radix Extract on Wound Healing in Streptozotocin-Induced Diabetic Rats

Impaired growth factor production, angiogenic response, macrophage function, and collagen accumulation have been shown to delay wound healing. Delayed wound healing is a debilitating complication of diabetes that leads to significant morbidity. In this study, curcumin and Lithospermi radix (LR) extract, which are used in traditional Chinese herbal medicine, were added within nanofibrous membranes to improve wound healing in a streptozotocin (STZ)-induced diabetic rat model. Gelatin-based nanofibers, which were constructed with curcumin and LR extract at a flow rate of 0.1 mL/hour and an applied voltage of 20 kV, were electrospun onto chitosan scaffolds to produce bilayer nanofibrous scaffolds (GC/L/C). The wounds treated with GC/L/C exhibited a higher recovery rate and transforming growth factor-beta (TGF-β) expression in Western blot assays. The decreased levels of pro-inflammatory markers, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), provided evidence for the anti-inflammatory effects of GC/L/C treatment. Chronic wounds treated with GC/L/C achieved better performance with a 58 ± 7% increase in recovery rate on the seventh day. Based on its anti-inflammatory and wound-healing effects, the GC/L/C bilayer nanofibrous scaffolds can be potential materials for chronic wound treatment.

Towards a Physiological Scale of Vocal Fold Agent-Based Models of Surgical Injury and Repair: Sensitivity Analysis, Calibration and Verification

Agent based models (ABM) were developed to numerically simulate the biological response to surgical vocal fold injury and repair at the physiological level. This study aimed to improve the representation of existing ABM through a combination of empirical and computational experiments. Empirical data of vocal fold cell populations including neutrophils, macrophages and fibroblasts were obtained using flow cytometry up to four weeks following surgical injury. Random Forests were used as a sensitivity analysis method to identify model parameters that were most influential to ABM outputs. Statistical Parameter Optimization Tool for Python was used to calibrate those parameter values to match the ABM-simulation data with the corresponding empirical data from Day 1 to Day 5 following surgery. Model performance was evaluated by verifying if the empirical data fell within the 95% confidence intervals of ABM outputs of cell quantities at Day 7, Week 2 and Week 4. For Day 7, all empirical data were within the ABM output ranges. The trends of ABM-simulated cell populations were also qualitatively comparable to those of the empirical data beyond Day 7. Exact values, however, fell outside of the 95% statistical confidence intervals. Parameters related to fibroblast proliferation were indicative to the ABM-simulation of fibroblast dynamics in final stages of wound healing.