Growth factors and chronic wound healing: past, present, and future

Computational therapeutic repurposing of tavaborole targeting arginase-1 for venous leg ulcer

Venous leg ulcers (VLUs) pose a growing healthcare challenge due to aging, obesity, and sedentary lifestyles. Despite various treatments available, addressing the complex nature of VLUs remains difficult. In this context, this study investigates repurposing boronated drugs to inhibit arginase 1 activity for VLU treatment. The molecular docking study conducted by Schrodinger GLIDE targeted the binuclear manganese cluster of arginase 1 enzyme (2PHO). Further, the ligand-protein complex was subjected to molecular dynamic studies at 500 ns in Gromacs-2019.4. Trajectory analysis was performed using the GROMACS simulation package of protein RMSD, RMSF, RG, SASA, and H-Bond. The docking study revealed intriguing results where the tavaborole showed a better docking score (-3.957 Kcal/mol) compared to the substrate L-arginine (-3.379 Kcal/mol) and standard L-norvaline (-3.141 Kcal/mol). Tavaborole interaction with aspartic acid ultimately suggests that the drug molecule binds to the catalytic site of arginase 1, potentially influencing the enzyme's function. The dynamics study revealed the compounds' stability and compactness of the protein throughout the simulation. The RMSD, RMSF, SASA, RG, inter and intra H-bond, PCA, FEL, and MMBSA studies affirmed the ligand-protein and protein complex flexibility, compactness, binding energy, van der waals energy, and solvation dynamics. These results revealed the stability and the interaction of the ligand with the catalytic site of arginase 1 enzyme, triggering the study towards the VLU treatment.

Design, fabrication, and evaluation of keratin and pectin incorporated supramolecular structured zero-oxidation state selenium nanogel blended 3D printed transdermal patch

This study investigates the synthesis of selenium nanoparticles (SeNPs), owing to the low cost and abundance of selenium. However, the toxicity of SeNP prompts the development of a selenium nanocomposite (SeNC) containing pectin, keratin, and ferulic acid to improve the bioactivity of Se[0]. Further, incorporating the SeNC in a suitable formulation for drug delivery as a transdermal patch was worth studying. Accordingly, various analytical techniques were used to characterize the SeNPs and the SeNC, confirming successful synthesis and encapsulation. The SeNC exhibited notable particle size of 448.2 ± 50.2 nm, high encapsulation efficiency (98.90 % ± 2.4 %), 28.1 ± 0.45 drug loading, and sustained drug release at pH 5.5. Zeta potential and XPS confirmed the zero-oxidation state. The supramolecular structure was evident from spectral analysis endorsing the semi-crystalline nature of the SeNC and SEM images showcasing flower-shaped structures. Further, the SeNC demonstrated sustained drug release (approx. 22 % at 48 h) and wound-healing potential in L929 fibroblast cells. Subsequently, the SeNC loaded into a gelling agent exhibited shear thinning properties and improved drug release by nearly 58 %. A 3D printed reservoir-type transdermal patch was developed utilizing the SeNC-loaded gel, surpassing commercially available patches in characteristics such as % moisture uptake, tensile strength, and hydrophobicity. The patch, evaluated through permeation studies and CAM assay, exhibited controlled drug release and angiogenic properties for enhanced wound healing. The study concludes that this patch can serve as a smart dressing with tailored functionality for different wound stages, offering a promising novel drug delivery system for wound healing.

Growth factors and growth factor gene therapies for treating chronic wounds

Chronic wounds are an unmet clinical need affecting millions of patients globally, and current standards of care fail to consistently promote complete wound closure and prevent recurrence. Disruptions in growth factor signaling, a hallmark of chronic wounds, have led researchers to pursue growth factor therapies as potential supplements to standards of care. Initial studies delivering growth factors in protein form showed promise, with a few formulations reaching clinical trials and one obtaining clinical approval. However, protein-form growth factors are limited by instability and off-target effects. Gene therapy offers an alternative approach to deliver growth factors to the chronic wound environment, but safety concerns surrounding gene therapy as well as efficacy challenges in the gene delivery process have prevented clinical translation. Current growth factor delivery and gene therapy approaches have primarily used single growth factor formulations, but recent efforts have aimed to develop multi-growth factor approaches that are better suited to address growth factor insufficiencies in the chronic wound environment, and these strategies have demonstrated improved efficacy in preclinical studies. This review provides an overview of chronic wound healing, emphasizing the need and potential for growth factor therapies. It includes a summary of current standards of care, recent advances in growth factor, cell-based, and gene therapy approaches, and future perspectives for multi-growth factor therapeutics.

The Efficacy of Local Autologous Platelet-Rich Plasma Prepared by Single and Double Spin Methods in the Treatment of Chronic Ulcer

BACKGROUND

Chronic nonhealing ulcers present significant challenges in diabetic, dermatological, and surgical patients. Platelet-rich plasma (PRP), enriched with bioactive factors, offers promise for wound healing enhancement. This study evaluates PRP's efficacy, prepared via single and double spin methods in nonhealing chronic ulcers.

METHODS

 Twenty-two patients aged 18-65 years participated and 100 mL of blood was drawn into citrate phosphate dextrose adenine (CPDA) bags with all aseptic precautions. PRP was prepared by single and double spin methods. Patient serum and 10% calcium gluconate were added to fibrin gel. PRP was injected around the ulcer and then dressed. Dressings were changed on the fifth, 15th, and 20th days with PRP. Evaluation occurred on day 30 using surface area and volume assessments by both methods.

RESULTS

The single spin PRP group and double spin PRP group had 11 patients each with hemoglobin range of 10.79±1.88 to 12.63±2.22 g/dL. Initial lesions (16.27 cm²) significantly reduced to 14.76 cm² after double spin PRP sessions (p=0.005) and Initial lesions (9.87 cm²) significantly reduced to 7.65 cm² after single spin PRP sessions (p=0.005). Platelet count differences between whole blood and PRP were significant (p<0.05).

CONCLUSIONS

The single spin PRP method exhibited considerable improvements in healing parameters, showcasing its potential for chronic ulcer management.

Tissue Regeneration on Rise: Dental Hard Tissue Regeneration and Challenges-A Narrative Review

Background

As people live longer, there is an increasing need for hard tissue regeneration and whole-tooth regeneration. Despite the advancements in the field of medicine, the field of regenerative dentistry is still challenging due to the complexity of dental hard tissues. Cross-disciplinary collaboration among material scientists, cellular biologists, and odontologists aimed at developing strategies and uncovering solutions related to dental tissue regeneration. Methodology. A search of the literature was done for pertinent research. Consistent with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 Statement, the electronic databases looked at were PubMed, Science Direct, Scopus, and Google Scholar, with the keyword search "hard dental tissue regeneration."

Results

Database analysis yielded a total of 476 articles. 222 duplicate articles have been removed in total. Articles that have no connection to the directed regeneration of hard dental tissue were disregarded. The review concluded with the inclusion of four studies that were relevant to our research objective.

Conclusion

Current molecular signaling network investigations and novel viewpoints on cellular heterogeneity have made advancements in understanding of the kinetics of dental hard tissue regeneration possible. Here, we outline the fundamentals of stem hard dental tissue maintenance, regeneration, and repair, as well as recent advancements in the field of hard tissue regeneration. These intriguing findings help establish a framework that will eventually enable basic research findings to be utilized towards oral health-improving medicines.

Novel Hydrogel Adjuvant of Chinese Medicine External Preparations for Accelerated Healing of Deep Soft Tissue Injuries

Traditional Chinese medicine external prescriptions have displayed excellent clinical effects for treating deep soft tissue injuries. However, the effects cannot be fully utilized due to the limitations of their dosage forms and usage methods. It is still a challenge to develop a satisfactory adjuvant of traditional Chinese medicine external prescriptions. Herein, a hydrogel adjuvant was prepared based on gallic acid coupled ε-poly-l-lysine and partially oxidized hyaluronic acid. The resulting adjuvant shows great physicochemical properties, low hemolysis rate (still much less than 5% at 5 mg/mL), excellent antibacterial ability (about 95% at 2 mg/mL), strong antioxidant ability (1.687 ± 0.085 mmol FeSO4/(g hydrogel) at 1 mg/mL), as well as outstanding biocompatibility. A clinically used Chinese medicine external preparation was selected as an example to investigate the effectiveness of the adjuvant in treating deep soft tissue injuries. The results show that the prescription can be evenly dispersed in the adjuvant. Moreover, the introduction of the prescription has not significantly changed these advanced properties of the adjuvant. Importantly, the hydrogel adjuvant significantly improves the effectiveness of the prescription in treating deep soft tissue injuries. This work offers an alternative approach to the development of a new-type adjuvant of Chinese medicine external preparations and also provides a new strategy for the combination of traditional Chinese medicine and hydrogel to treat clinical diseases.

Electrospun organic/inorganic hybrid nanofibers for accelerating wound healing: a review

Electrospun nanofiber membranes hold great promise as scaffolds for tissue reconstruction, mirroring the natural extracellular matrix (ECM) in their structure. However, their limited bioactive functions have hindered their effectiveness in fostering wound healing. Inorganic nanoparticles possess commendable biocompatibility, which can expedite wound healing; nevertheless, deploying them in the particle form presents challenges associated with removal or collection. To capitalize on the strengths of both components, electrospun organic/inorganic hybrid nanofibers (HNFs) have emerged as a groundbreaking solution for accelerating wound healing and maintaining stability throughout the healing process. In this review, we provide an overview of recent advancements in the utilization of HNFs for wound treatment. The review begins by elucidating various fabrication methods for hybrid nanofibers, encompassing direct electrospinning, coaxial electrospinning, and electrospinning with subsequent loading. These techniques facilitate the construction of micro-nano structures and the controlled release of inorganic ions. Subsequently, we delve into the manifold applications of HNFs in promoting the wound regeneration process. These applications encompass hemostasis, antibacterial properties, anti-inflammatory effects, stimulation of cell proliferation, and facilitation of angiogenesis. Finally, we offer insights into the prospective trends in the utilization of hybrid nanofiber-based wound dressings, charting the path forward in this dynamic field of research.

Effects of plasma rich in growth factors on wound healing in patients with venous ulcers

Introduction

Significant evidence suggests that plasma-rich in growth factors (PRGF) favor the repair of chronic wounds, enabling a rapid return to functionality. However, components of PRGF and their effects on persistent ulcers and epithelial tissues are not well characterized. The goals of this research were to analyze the biological properties of platelet-derived factors, to examine their effectiveness on healing of venous ulcers, and to establish a correlation with clinical and sociodemographic data.

Methods

For the preparation of PRGF, the centrifugation technique was used, obtaining a 100 % autologous and biocompatible blood sample that was treated with sodium citrate and calcium chloride. The patients were attended weekly at the outpatient clinic for nursing consultation and wound dressing changes, with PRGF application every 15 days. The treatment protocols are described, and follow-up results are reported.

Results

Initially, the patients' ulcers ranged in sizes from 4 to 84 cm2. After 12 weeks of treatment, there was a significant mean reduction of 46.2 % in ulcer area. At baseline, epithelial tissue was absent in all venous ulcers, but its presence grew significantly by the treatment period. However, the reduction of the area of the ulcers did not show significant correlation with the concentrations of the patient's growth factors.

Conclusions

Using the established protocol for PRGF isolating, it was possible to obtain a product with the presence of the six growth factors related to tissue regeneration and observed a positive response on wound healing following treatment of venous ulcers, with capacity to accelerate re-epithelialization and restore the skin functional integrity.

The Role of Growth Factor Delivery Systems on Cellular Activities of Dental Stem Cells: A Systematic Review (Part II)

OBJECTIVE

The current systematic review aims to provide the available ex vivo evidence evaluating the biological interactions of dental stem cells (DSCs) and growth factor delivery systems.

METHODS

Following the Preferred Reporting Items for a Systematic Reviews and Meta-Analyses (PRISMA) guidelines, systematic search was conducted in the electronic databases (PubMed/Medline, Scopus, Web of Science, and Google Scholar) up to January 2022. Studies evaluating the biological interactions of DSCs and growth factor delivery systems were included. The outcome measures were cell cytocompatibility, mineralization, and differentiation.

RESULTS

Sixteen studies were selected for the qualitative synthesis. The following growth factor delivery systems exhibit adequate cytocompatibility, enhanced mineralization, and osteo/odontoblast differentiation potential of DSCs: 1) Fibroblast growth factor (FGF-2)-loaded-microsphere and silk fibroin, 2) Bone morphogenic protein-2 (BMP-2)-loaded-microsphere and mesoporous calcium silicate scaffold, 3) Transforming growth factor Beta 1 (TGF-ß1)-loaded-microsphere, glass ionomer cement (GIC), Bio-GIC and liposome, 4) TGF-ß1-loaded-nanoparticles/scaffold, 5) Vascular endothelial growth factor (VEGF)-loaded-fiber and hydrogel, 6) TGF-ß1/VEGF-loaded-nanocrystalline calcium sulfate/hydroxyapatite/calcium sulfate, 7) Epidermal growth factor-loaded- nanosphere, 8) Stem cell factor/DSCs-loaded-hydrogel and Silk fibroin, 9) VEGF/BMP-2/DSCs-loaded-Three-dimensional matrix, 10) VEGF/DSCs-loaded-microsphere/hydrogel, and 11) BMP-2/DSCs and VEGF/DSCs-loaded-Collagen matrices. The included delivery systems showed viability, except for Bio-GIC on day 3. The choice of specific growth factors and delivery systems (i.e., BMP-2-loaded-microsphere and VEGF-loaded-hydrogel) resulted in a greater gene expression.

CONCLUSIONS

This study, with low-level evidence obtained from ex vivo studies, suggests that growth factor delivery systems induce cell proliferation, mineralization, and differentiation toward a therapeutic potential in regenerative endodontics.

Double hits with bioactive nanozyme based on cobalt-doped nanoglass for acute and diabetic wound therapies through anti-inflammatory and pro-angiogenic functions

Regeneration of pathological wounds, such as diabetic ulcers, poses a significant challenge in clinical settings, despite the widespread use of drugs. To overcome clinical side effects and complications, drug-free therapeutics need to be developed to promote angiogenesis while overcoming inflammation to restore regenerative events. This study presents a novel bioactive nanozyme based on cobalt-doped nanoglass (namely, CoNZ), which exhibits high enzymatic/catalytic activity while releasing therapeutic ions. Cobalt oxide "Co3O4" tiny crystallites produced in situ through a chemical reaction with H2O2 within CoNZ nanoparticles play a crucial role in scavenging ROS. Results showed that CoNZ-treatment to full-thickness skin wounds in mice significantly accelerated the healing process, promoting neovascularization, matrix deposition, and epithelial lining while reducing pro-inflammatory signs. Notably, CoNZ was highly effective in treating pathological wounds (streptozotocin-induced diabetic wounds). Rapid scavenging of ROS by CoNZ and down-regulation of pro-inflammatory markers while up-regulating tissue healing signs with proliferative cells and activated angiogenic factors contributed to the observed healing events. In vitro experiments involving CoNZ-cultures with macrophages and endothelial cells exposed to high glucose and ROS-generating conditions further confirmed the effectiveness of CoNZ. CoNZ-promoted angiogenesis was attributed to the release of cobalt ions, as evidenced by the comparable effects of CoNZ-extracted ionic medium in enhancing endothelial migration and tubule formation via activated HIF-1α. Finally, we compared the in vivo efficacy of CoNZ with the clinically-available drug deferoxamine. Results demonstrated that CoNZ was as effective as the drug in closing the diabetic wound, indicating the potential of CoNZ as a novel drug-free therapeutic approach.

Network of Extracellular Traps in the Pathogenesis of Sterile Chronic Inflammatory Diseases: Role of Oxidative Stress and Potential Clinical Applications

Significance: Extracellular traps (ETs) represent structured frameworks that comprised DNA embellished with histones and granular proteins extruded by immune cells in response to various stimuli. Immune cells contribute to adverse effects of chronic inflammation via ET generation, promoting the release of nuclear chromatin, reactive oxygen species (ROS), and bioactive proteins into the extracellular matrix. Recent Advances: The occurrence of ET formation has been documented across diverse immune cell types. The excessive production of ROS during the activation of these cells has the potential to initiate substantial DNA damage, culminating in chromosome decondensation. The inflammatory microenvironment fosters ROS and ET generation, impacting tissue microenvironment remodeling. Recent studies reveal ET involvement in sustaining persistent inflammation, promoting angiogenesis, and initiating thrombotic processes. Critical Issues: This review elucidates ET participation in chronic inflammatory disease etiology, detailing ROS-dependent and ROS-independent ET formation mechanisms and their contextual manifestations. It discusses diverse immune cell-derived ETs in the inflammatory milieu and their responses to therapies. Furthermore, the review emphasizes the significance of ETs as potential biomarkers and envisions prophylactic strategies against ET-associated chronic inflammation. Future Directions: Subsequent investigations are warranted to uncover the intricate mechanisms governing the resolution of inflammation through ETs in normal physiological processes. Moreover, a comprehensive understanding of the aberrant pathways driving ET formation in persistent inflammation is imperative. Prospective research endeavors should focus on executing expansive clinical studies to discern the involvement of ETs in both the diagnostic and prognostic facets of inflammatory diseases, thereby shedding light on their prospective utility as biomarkers.

Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine

Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.

Surface material of acoustic transmitters influences the inflammatory response of rainbow trout (Oncorhynchus mykiss) during long-term implantation

Telemetry tags are a widely used technology for tracking animals that are difficult to observe in their natural environment. This technology has been increasingly used to monitor and study populations of high value salmonid species in Canadian waters. This study expands on a previous study of the impacts of tag implantation on the immune system of Rainbow Trout (Oncorhynchus mykiss). Pro-inflammatory cytokines and protein level markers were examined in fish that underwent peritoneal implantation of three tag types and compared to a sham surgery control group. The different materials on the surface of the tags showed differential immune induction extending over a two-month period. This included peritoneal total protein, IL-1β protein, the immunoglobulins IgT and IgM, as well as pro-inflammatory transcripts in the spleen. These results are suggestive of a prolonged, costly foreign body response which may be differentially induced by the different types of tag coating, with ceramic tags being least immunogenic. Examining tag impacts at the level of the immune system will facilitate the development of more biocompatible tags which will improve data fidelity. This will support more effective strategies for the management of fisheries resources.

Thermosensitive and antioxidant wound dressings capable of adaptively regulating TGFβ pathways promote diabetic wound healing

Various therapies have been utilized for treating diabetic wounds, yet current regiments do not simultaneously address the key intrinsic causes of slow wound healing, i.e., abnormal skin cell functions (particularly migration), delayed angiogenesis, and chronic inflammation. To address this clinical gap, we develop a wound dressing that contains a peptide-based TGFβ receptor II inhibitor (PTβR2I), and a thermosensitive and reactive oxygen species (ROS)-scavenging hydrogel. The wound dressing can quickly solidify on the diabetic wounds following administration. The released PTβR2I inhibits the TGFβ1/p38 pathway, leading to improved cell migration and angiogenesis, and decreased inflammation. Meanwhile, the PTβR2I does not interfere with the TGFβ1/Smad2/3 pathway that is required to regulate myofibroblasts, a critical cell type for wound healing. The hydrogel's ability to scavenge ROS in diabetic wounds further decreases inflammation. Single-dose application of the wound dressing significantly accelerates wound healing with complete wound closure after 14 days. Overall, using wound dressings capable of adaptively modulating TGFβ pathways provides a new strategy for diabetic wound treatment.

Research progress on the role of PDGF/PDGFR in type 2 diabetes

Platelet-derived growth factors (PDGFs) are basic proteins stored in the α granules of platelets. PDGFs and their receptors (PDGFRs) are widely expressed in platelets, fibroblasts, vascular endothelial cells, platelets, pericytes, smooth muscle cells and tumor cells. The activation of PDGFR plays a number of critical roles in physiological functions and diseases, including normal embryonic development, cellular differentiation, and responses to tissue damage. In recent years, emerging experimental evidence has shown that activation of the PDGF/PDGFR pathway is involved in the development of diabetes and its complications, such as atherosclerosis, diabetic foot ulcers, diabetic nephropathy, and retinopathy. Research on targeting PDGF/PDGFR as a treatment has also made great progress. In this mini-review, we summarized the role of PDGF in diabetes, as well as the research progress on targeted diabetes therapy, which provides a new strategy for the treatment of type 2 diabetes.

Immune Fitness, Migraine, and Headache Complaints in Individuals with Self-Reported Impaired Wound Healing

Background

Having chronic wounds and impaired wound healing are associated with psychological distress. The current study aims to evaluate migraine and headache complaints in young adults with self-reported impaired wound healing.

Methods

A survey was conducted among N=1935 young adults (83.6% women), 18-30 years old, living in the Netherlands. Wound healing status was verified, immune fitness was assessed using a single-item rating scale, and ID Migraine was completed. In addition, several questions were answered on past year's headache experiences (including frequency, quantity, type, location, and severity).

Results

In both the control group (p < 0.001) and the IWH group (p = 0.002) immune fitness was significantly lower among those that reported headaches compared to those that reported no headaches. Individuals with self-reported impaired wound healing (IWH) scored significantly higher on the ID Migraine scale, and individuals of the IWH group scored significantly more often positive for migraine (ie, an ID Migraine score ≥2). They reported a younger age of onset of experiencing headaches, and significantly more often reported having a beating or pounding headache than the control group. Compared to the control group, the IWH group reported being significantly more limited in their daily activities compared to the control group.

Conclusion

Headaches and migraines are more frequently reported by individuals with self-reported impaired wound healing, and their reported immune fitness is significantly poorer compared to healthy controls. These headache and migraine complaints significantly limit them in their daily activities.

Wound Dressing Modifications for Accelerated Healing of Infected Wounds

Infections that occur during wound healing involve the most frequent complications in the field of wound care which not only inhibit the whole process but also lead to non-healing wound formation. The diversity of the skin microbiota and the wound microenvironment can favor the occurrence of skin infections, contributing to an increased level of morbidity and even mortality. As a consequence, immediate effective treatment is required to prevent such pathological conditions. Antimicrobial agents loaded into wound dressings have turned out to be a great option to reduce wound colonization and improve the healing process. In this review paper, the influence of bacterial infections on the wound-healing phases and promising modifications of dressing materials for accelerated healing of infected wounds are discussed. The review paper mainly focuses on the novel findings on the use of antibiotics, nanoparticles, cationic organic agents, and plant-derived natural compounds (essential oils and their components, polyphenols, and curcumin) to develop antimicrobial wound dressings. The review article was prepared on the basis of scientific contributions retrieved from the PubMed database (supported with Google Scholar searching) over the last 5 years.

Characterization of silk fibroin-based microneedles and in vitro study of stromal cell-derived factor-1-loaded microneedles on adipose stem cell recruitment

Silk fibroin (SF) has good biocompatibility, degradability and mechanical properties. In this study, SF-based microneedle (MN) patches were fabricated as stromal cell-derived factor-1 (SDF-1) carriers that may be used for adipose stem cell (ASC) recruitment. Therefore, SF was chosen as the main MN material to achieve sustained drug release. In addition, the variations in SF-based MN crystallinity after water annealing treatment were also determined. The results indicated that SF-based MN patches were successfully fabricated with a 3M™ commercial template and Polydimethylsiloxane mold. Through optical coherence tomography, it was found that all of the SF-based MN patches prepared in this study had sufficient strength to penetrate the skin to a depth of approximately 400 μm. Sustained release of the model drug-dextran from the SF-based MNs was demonstrated. Although SF-based MNs release SDF-1 in a sustained manner, the quantity released can be regulated and improved. Subsequently, dual-layer SDF-1-loaded MNs fabricated with a gelatin tip and SF body were prepared to enhance SDF-1 release for ASC recruitment. SF-based MNs can show good penetration ability and provide good sustained release while dual-layer MNs can regulate the amount of drug released, which could present an alternative for stem cell therapy.

Examination of the effects of kefir on healing factors in a mice burn model infected with E.coli, S.aureus and P.aeruginosa using qRT-PCR

Burn areas are susceptible to bacterial growth and infections, particularly in cases with lengthy periods of hospital stay. Burn wound healing, which involves various molecular and cellular mechanisms, continues to be a significant problem. Growth factors and cytokines play an active and vital role in wound healing. In the present study, the effects of kefir on wound healing in a 2nd-degree mouse burn model infected with e.coli, s.aureus and p.aeruginosa were investigated in vitro. In order to clarify the effects of kefir in the wound healing process, the macroscopic changes in kefir-applied scar tissue as well as wound depth and width were examined and IL-1α, IL-1β, IL-6, IL-8, IL-10 and TNF-α, VEGF, TGF-β protein levels were determined using the qRT-PCR method. The findings of the present study show that kefir has a positive impact on the factors playing a role in wound healing and accelerates the healing process.

Fabrication and Bioactivity of Peptide-Conjugated Biomaterial Tissue Engineering Constructs

Tissue engineering combines materials engineering, cells and biochemical factors to improve, restore or replace various types of biological tissues. A nearly limitless combination of these strategies can be combined, providing a means to augment the function of a number of biological tissues such as skin tissue, neural tissue, bones, and cartilage. Compounds such as small molecule therapeutics, proteins, and even living cells have been incorporated into tissue engineering constructs to influence biological processes at the site of implantation. Peptides have been conjugated to tissue engineering constructs to circumvent limitations associated with conjugation of proteins or incorporation of cells. This review highlights various contemporary examples in which peptide conjugation is used to overcome the disadvantages associated with the inclusion of other bioactive compounds. This review covers several peptides that are commonly used in the literature as well as those that do not appear as frequently to provide a broad scope of the utility of the peptide conjugation technique for designing constructs capable of influencing the repair and regeneration of various bodily tissues. Additionally, a brief description of the construct fabrication techniques encountered in the covered examples and their advantages in various tissue engineering applications is provided.

Effect of ascorbic acid and epidermal growth factor in a rat tibia defect

PURPOSE

Bone repair aims to restore the anatomical, biomechanical, and functional integrity of the affected structure. Here we study the effects of ascorbic acid (AA) and epidermal growth factor (EGF) applied in a single dose and in combination on the repair of a noncritical bone defect model.

METHODS

Twenty-four rats were divided into four groups: an intact G-1 control group, and three groups that underwent a noncritical bone defect in the right tibia: G-2 treated with AA, G-3 treated with EGF, and G-4 treated with AA in combination with EGF. After 21 days of treatment, rats were sacrificed, the tibias were dissected and a destructive biomechanical analysis of three-point flexion test was performed in a universal testing machine; the values of stiffness, resistance, maximum energy, and energy at maximum load were statistically compared.

RESULTS

G-3 and G-4 recovered the biomechanical properties of strength and stiffness of an intact tibia 3 weeks after their application. Not so the energy and energy at maximum load. For G-2, only the stiffness of an intact tibia was recovered.

CONCLUSIONS

EGF and AA-EGF applied to a noncritical bone defect in the rat tibia favors the recovery of bone resistance and stiffness.

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.

Botulinum Toxin Type A for the Treatment of Skin Ulcers: A Review Article

The normal biological wound healing process consists of three precisely and highly programmed phases that require optimal conditions including internal and external factors. Any negative factors that disrupt the sequence or time frame of the healing mechanism can result in a non-healing wound or chronic ulcers. Botulinum neurotoxin A (BoNT-A) which is generally known as anti-contraction of muscles has been reported as a successful treatment in various types of chronic ulcers. The aim of this study is to review the outcome of treatment with BoNT-A for chronic skin ulcers. The results demonstrated some positive effects of BoNT-A on chronic ulcers. Ischemic ulcers secondary to Raynaud’s phenomenon seem to be the most promising type of ulcers that have benefited from BoNT-A. The rationale behind using BoNT-A to fasten the wound healing process is also discussed. Further clinical trial studies should be conducted to affirm the efficacy of wound healing using BoNT-A administration.

Identification of Angiogenic Cargoes in Human Fibroblasts-Derived Extracellular Vesicles and Induction of Wound Healing

A complete redevelopment of the skin remains a challenge in the management of acute and chronic wounds. Recently, the application of extracellular vesicles (EVs) for soft tissue wound healing has received much attention. As fibroblasts are fundamental cells for soft tissues and skin, we investigate the proangiogenic factors in human normal fibroblast-derived EVs (hNF-EVs) and their effects on wound healing. Normal fibroblasts were isolated from human skin tissues and characterized by immunofluorescence (IF) and Western blotting (WB). hNF-EVs were isolated by ultracentrifugation and characterized using transmission electron microscopy and WB. The proangiogenic cargos in hNF-EVs were identified by a TaqMan assay and a protein array. Other in vitro assays, including internalization assays, cell counting kit-8 analysis, scratch wound assays, WBs, and tube formation assays were conducted to assess the effects of hNF-EVs on fibroblasts and endothelial cells. A novel scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue was applied onto full-thickness skin wounds in mice. The wound healing therapeutical effect of hNF-EVs was assessed by calculating the rate of wound closure and through histological analysis. Isolated hNF was confirmed by verifying the expression of the fibroblast markers vimentin, αSMA, Hsp70, and S100A4. Isolated hNF-EVs showed intact EVs with round morphology, enriched in CD81 and CD63, and devoid of the cell markers GM130, Calnexin, and Cytochrome C. Our TaqMan assay showed that hNF-EVs were enriched in miR130a and miR210, and protein arrays showed enriched levels of the proangiogenic proteins’ vascular endothelial growth factor (VEGF)-D and CXCL8. Next, we found that the internalization of hNF-EVs into hNF increased the proliferation and migration of hNF, in addition to increasing the expression of bFGF, MMP2, and αSMA. The internalization of hNF-EVs into the endothelial cells increased their proliferation and tube formation. A scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue accelerated the wound healing rate in full-thickness skin wounds in mice, and the treatments increased the cellular density, deposition, and maturation of collagens in the wounds. Moreover, the scaffold-free noninvasive delivery of hNF-EVs with or without fibrin glue increased the VEGF and CD31 expression in the wounds, indicating that hNF-EVs have an angiogenic ability to achieve complete skin regeneration. These findings open up for new treatment strategies to be developed for wound healing. Further, we offer a new approach to the efficient, scaffold-free noninvasive delivery of hNF-EVs to wounds.

Phytochemistry and Biological Activity of Medicinal Plants in Wound Healing: An Overview of Current Research

Wound healing is a complicated process, and the effective management of wounds is a major challenge. Natural herbal remedies have now become fundamental for the management of skin disorders and the treatment of skin infections due to the side effects of modern medicine and lower price for herbal products. The aim of the present study is to summarize the most recent in vitro, in vivo, and clinical studies on major herbal preparations, their phytochemical constituents, and new formulations for wound management. Research reveals that several herbal medicaments have marked activity in the management of wounds and that this activity is ascribed to flavonoids, alkaloids, saponins, and phenolic compounds. These phytochemicals can act at different stages of the process by means of various mechanisms, including anti-inflammatory, antimicrobial, antioxidant, collagen synthesis stimulating, cell proliferation, and angiogenic effects. The application of natural compounds using nanotechnology systems may provide significant improvement in the efficacy of wound treatments. Increasing the clinical use of these therapies would require safety assessment in clinical trials.

Platelet-Released Growth Factors Influence Wound Healing-Associated Genes in Human Keratinocytes and Ex Vivo Skin Explants

Platelet-released growth factors (PRGFs) or other thrombocyte concentrate products, e.g., Platelet-Rich Fibrin (PRF), have become efficient tools of regenerative medicine in many medical disciplines. In the context of wound healing, it has been demonstrated that treatment of chronic or complicated wounds with PRGF or PRF improves wound healing in the majority of treated patients. Nevertheless, the underlying cellular and molecular mechanism are still poorly understood. Therefore, we aimed to analyze if PRGF-treatment of human keratinocytes caused the induction of genes encoding paracrine factors associated with successful wound healing. The investigated genes were Semaphorin 7A (SEMA7A), Angiopoietin-like 4 (ANGPLT4), Fibroblast Growth Factor-2 (FGF-2), Interleukin-32 (IL-32), the CC-chemokine-ligand 20 (CCL20), the matrix-metalloproteinase-2 (MMP-2), the chemokine C-X-C motif chemokine ligand 10 (CXCL10) and the subunit B of the Platelet-Derived Growth Factor (PDGFB). We observed a significant gene induction of SEMA7A, ANGPLT4, FGF-2, IL-32, MMP-2 and PDGFB in human keratinocytes after PRGF treatment. The CCL20- and CXCL10 gene expressions were significantly inhibited by PRGF therapy. Signal transduction analyses revealed that the PRGF-mediated gene induction of SEMA7A, ANGPLT4, IL-32 and MMP-2 in human keratinocytes was transduced via the IL-6 receptor pathway. In contrast, EGF receptor signaling was not involved in the PRGF-mediated gene expression of analyzed genes in human keratinocytes. Additionally, treatment of ex vivo skin explants with PRGF confirmed a significant gene induction of SEMA7A, ANGPLT4, MMP-2 and PDGFB. Taken together, these results describe a new mechanism that could be responsible for the beneficial wound healing properties of PRGF or related thrombocytes concentrate products such as PRF.

Antioxidant, anti-inflammatory, and wound healing effects of topical silver-doped zinc oxide and silver oxide nanocomposites

Silver nanoparticles (Ag-NPs), silver oxide nanoparticles (AgO-NPs), and zinc oxide nanoparticles (ZnO-NPs) have healing, antibacterial, and antioxidant properties. Furthermore, Ag-NPs and ZnO-NPs also have anti-inflammatory properties. In this study, we synthesized a nanocomposite using Ag-ZnO and AgO-NPs (Ag-ZnO/AgO NPs). The structural and morphological properties of nanocrystals and nanocomposite were investigated by X-ray diffraction and scanning electronics microscopic. The wurtzite crystalline structure of Ag-ZnO and two morphologies for the nanocomposite (nanorods and nanoplatelets) were determined. Topical treatment with 1% Ag-ZnO/AgO NPs was compared to untreated wounds (control group). Wounds were induced in the dorsal region of BALB/c mice and evaluated after 3, 7, 14, and 21 days of treatment. The nanocomposite demonstrated anti-inflammatory and antioxidant capacities. In addition, wounds treated with Ag-ZnO/AgO NPs showed accelerated closure, non-cytotoxicity, especially on keratinocytes and collagen deposition, and increased metalloproteinases 2 and 9 activity. The nanocomposite improved healing by reducing the inflammatory process, protecting tissues from damage caused by free radicals, and increasing collagen deposition in the extracellular matrix. These characteristics contributed to the accelerated wound closure process. Thus, Ag-ZnO/AgO NPs show potential for can be a strategy for topical use in formulations of new drugs to treat wounds.

ROS-Scavenging Therapeutic Hydrogels for Modulation of the Inflammatory Response

Although reactive oxygen species (ROS) are essential for cellular processes, excessive ROS could be a major cause of various inflammatory diseases because of the oxidation of proteins, DNA, and membrane lipids. It has recently been suggested that the amount of ROS could thus be regulated to treat such physiological disorders. A ROS-scavenging hydrogel is a promising candidate for therapeutic applications because of its high biocompatibility, 3D matrix, and ability to be modified. Approaches to conferring antioxidant properties to normal hydrogels include embedding ROS-scavenging catalytic nanoparticles, modifying hydrogel polymer chains with ROS-adsorbing organic moieties, and incorporating ROS-labile linkers in polymer backbones. Such therapeutic hydrogels can be used for wound healing, cardiovascular diseases, bone repair, ocular diseases, and neurodegenerative disorders. ROS-scavenging hydrogels could eliminate oxidative stress, accelerate the regeneration process, and show synergetic effects with other drugs or therapeutic molecules. In this review, the mechanisms by which ROS are generated and scavenged in the body are outlined, and the effects of high levels of ROS and the resulting oxidative stress on inflammatory diseases are described. Next, the mechanism of ROS scavenging by hydrogels is explained depending on the ROS-scavenging agents embedded within the hydrogel. Lastly, the recent achievements in the development of ROS-scavenging hydrogels to treat various inflammation-associated diseases are presented.

Identification and localization of growth factor genes in the sea cucumber, Holothuria scabra

The sea cucumber Holothuria scabra is both an economically important species in Asian countries and an emerging experimental model for research studies in regeneration and medicinal bioactives. Growth factors and their receptors are known to be key components that guide tissue repair and renewal, yet validation of their presence in H. scabra has not been established. We performed a targeted in silico search of H. scabra transcriptome data to elucidate conserved growth factor family and receptor genes. In total, 42 transcripts were identified, of which 9 were validated by gene cloning and sequencing. The H. scabra growth factor genes, such as bone morphogenetic protein 2A (BMP 2A), bone morphogenetic protein 5-like (BMP5-like), neurotrophin (NT) and fibroblast growth factor 18 (FGF18), were selected for further analyses, including phylogenetic comparison and spatial gene expression using RT-PCR and in situ hybridization. Expression of all genes investigated were widespread in multiple tissues. However, BMP 2A, BMP5-like and NT were found extensively in the radial nerve cord cells, while FGF18 was highly expressed in connective tissue layer of the body wall. Our identification and expression analysis of the H. scabra growth factor genes provided the molecular information of growth factors in this species which may ultimately complement the research in regenerative medicine.

Arginase Signalling as a Key Player in Chronic Wound Pathophysiology and Healing

Arginase (ARG) represents an important evolutionarily conserved enzyme that is expressed by multiple cell types in the skin. Arg acts as the mediator of the last step of the urea cycle, thus providing protection against excessive ammonia under homeostatic conditions through the production of L-ornithine and urea. L-ornithine represents the intersection point between the ARG-dependent pathways and the urea cycle, therefore contributing to cell detoxification, proliferation and collagen production. The ARG pathways help balance pro- and anti-inflammatory responses in the context of wound healing. However, local and systemic dysfunctionalities of the ARG pathways have been shown to contribute to the hindrance of the healing process and the occurrence of chronic wounds. This review discusses the functions of ARG in macrophages and fibroblasts while detailing the deleterious implications of a malfunctioning ARG enzyme in chronic skin conditions such as leg ulcers. The review also highlights how ARG links with the microbiota and how this impacts on infected chronic wounds. Lastly, the review depicts chronic wound treatments targeting the ARG pathway, alongside future diagnosis and treatment perspectives.

Emerging Nitric Oxide and Hydrogen Sulfide Releasing Carriers for Skin Wound Healing Therapy

Nitric oxide (NO) and hydrogen sulfide (H₂ S) have been recognized as important signalling molecules involved in multiple physiological functions, including wound healing. Their exogenous delivery has been established as a new route for therapies, being the topical application the nearest to commercialization. Nevertheless, the gaseous nature of these therapeutic agents and their toxicity at high levels imply additional challenges in the design of effective delivery systems, including the tailoring of their morphology and surface chemistry to get controllable release kinetics and suitable lifetimes. This review highlights the increasing interest in the use of these gases in wound healing applications by presenting the various potential strategies in which NO and/or H₂ S are the main therapeutic agents, with focus on their conceptual design, release behaviour and therapeutic performance. These strategies comprise the application of several types of nanoparticles, polymers, porous materials, and composites as new releasing carriers of NO and H₂ S, with characteristics that will facilitate the application of these molecules in the clinical practice.

Preparation of Foam Dressings Based on Gelatin, Hyaluronic Acid, and Carboxymethyl Chitosan Containing Fibroblast Growth Factor-7 for Dermal Regeneration

Wound recovery close to the function of the native skin is the goal of wound healing. In this study, we prepared foam dressings (FDs; 2-GHC-FD-1–9, 5-GHC-FD-1–9, and 10-GHC-FD-1–9) composed of various concentrations of gelatin, hyaluronic acid, and carboxymethyl chitosan, which are chemically interconnected through amide bond formation, for evaluating wound healing. Tensile and cell proliferation tests showed that 2-GHC-FD-1–9 are suitable for wound dressing. For further evaluation, three types of FDs, 2-GHC-FD-1, 2-GHC-FD-4, and 2-GHC-FD-8 were chosen. The results of animal intradermal reactivity, water vapor transmission rate, and absorption rate of the three FDs indicated that 2-GHC-FD-8 is the most appropriate scaffold for wound healing. For wound healing acceleration, various concentrations of fibroblast growth factor-7 (FGF-7) was soaked in 2-GHC-FD-8 (2-GHC-FD-8/F1-6) and evaluated by using scanning electron microscopy, cell proliferation, release behavior, and in vivo animal tests. The FDs showed interconnected porous structures, increased cell proliferation until 8.0 × 10⁻¹¹ M, controlled release with initial burst within 1 h, and sustained release for 48 h. The results of the animal test showed an appropriate concentration of FGF-7 for wound healing. In addition, 2-GHC-FD-8 is a suitable scaffold for wound healing. Therefore, we suggest that 2-GHC-FD-8/F3 is a useful wound dressing for accelerating wound healing.

Discovery of Hyperstable Noncanonical Plant-Derived Epidermal Growth Factor Receptor Agonist and Analogs

Here, we report the discovery of the first plant-derived and noncanonical epidermal growth factor receptor (EGFR) agonist, the 36-residue bleogen pB1 from Pereskia bleo of the Cactaceae family. We show that bleogen pB1 is a low-affinity EGFR agonist using a suite of chemical, biochemical, cellular, and animal experiments which include incisor eruption and wound-healing mouse models. A focused positional scanning pB1 library of Ala- and d-amino acid scans yielded a high-affinity pB1 analog, [K29k]pB1, with a 60-fold-improved EGFR affinity and mitogenicity. We show that the potency of [K29k]pB1 and the epidermal growth factor (EGF) is comparable in a diabetic mouse wound-healing model. We also show that both bleogen pB1 and [K29k]pB1 are hyperstable, being >100-fold more stable than EGF against proteolytic degradation. Overall, our discovery of a noncanonical proteolytic-resistant EGFR agonist scaffold could open new avenues for developing wound healing and skin regeneration therapeutics and biomaterials.

Bioresponsive supramolecular hydrogels for hemostasis, infection control and accelerated dermal wound healing

Injectable, drug-releasing hydrogel scaffolds with multifunctional properties including hemostasis and anti-bacterial activity are essential for successful wound healing; however, designing ideal materials is still challenging. Herein, we demonstrate the fabrication of a biodegradable, temperature-pH dual responsive supramolecular hydrogel (SHG) scaffold based on sodium alginate/poly(N-vinyl caprolactam) (AG/PVCL) through free radical polymerization and the subsequent chemical and ionic cross-linking. A natural therapeutic molecule, tannic acid (TA)-incorporated SHG (AG/PVCL-TA), was also fabricated and its hemostatic and wound healing efficiency were studied. In the AG/PVCL-TA system, TA acts as a therapeutic molecule and also substitutes as an effective gelation binder. Notably, the polyphenol-arm structure and diverse bonding abilities of TA can hold polymer chains through multiple bonding and co-ordinate cross-linking, which were vital in the formation of the mechanically robust AG/PVCL-TA. The SHG formation was successfully balanced by varying the composition of SA, VCL, TA and cross-linkers. The AG/PVCL-TA scaffold was capable of releasing a therapeutic dose of TA in a sustained manner under physiological temperature-pH conditions. AG/PVCL-TA displayed excellent free radical scavenging, anti-inflammatory, anti-bacterial, and cell proliferation activity towards the 3T3 fibroblast cell line. The wound healing performance of AG/PVCL-TA was further confirmed in skin excision wound models, which demonstrated the potential application of AG/PVCL-TA for skin regeneration and rapid wound healing.

Electrospun nanofibers promote wound healing: theories, techniques, and perspectives

At present, the clinical strategies for treating chronic wounds are limited, especially when it comes to pain relief and rapid wound healing. Therefore, there is an urgent need to develop alternative treatment methods. This paper provides a systematic review on recent researches on how electrospun nanofiber scaffolds promote wound healing and how the electrospinning technology has been used for fabricating multi-dimensional, multi-pore and multi-functional nanofiber scaffolds that have greatly promoted the development of wound healing dressings. First, we provide a review on the four stages of wound healing, which is followed by a discussion on the evolvement of the electrospinning technology, what is involved in electrospinning devices, and factors affecting the electrospinning process. Finally, we present the possible mechanisms of electrospun nanofibers to promote wound healing, the classification of electrospun polymers, cell infiltration favoring fiber scaffolds, antibacterial fiber scaffolds, and future multi-functional scaffolds. Although nanofiber scaffolds have made great progress as a type of multi-functional biomaterial, major challenges still remain for commercializing them in a way that fully meets the needs of patients.

Fibroblast Growth Factor in Diabetic Foot Ulcer: Progress and Therapeutic Prospects

Diabetic foot ulcer (DFU) is a combination of neuropathy and various degrees of peripheral vasculopathy in diabetic patients resulting in lower extremity infection, ulcer formation, and deep-tissue necrosis. The difficulty of wound healing in diabetic patients is caused by a high glucose environment and various biological factors in the patient. The patients' skin local microenvironment changes and immune chemotactic response dysfunction. Wounds are easy to be damaged and ulcerated repeatedly, but difficult to heal, and eventually develop into chronic ulcers. DFU is a complex biological process in which many cells interact with each other. A variety of growth factors released from wounds are necessary for coordination and promotion of healing. Fibroblast growth factor (FGF) is a family of cell signaling proteins, which can mediate various processes such as angiogenesis, wound healing, metabolic regulation and embryonic development through its specific receptors. FGF can stimulate angiogenesis and proliferation of fibroblasts, and it is a powerful angiogenesis factor. Twenty-three subtypes have been identified and divided into seven subfamilies. Traditional treatments for DFU can only remove necrotic tissue, delay disease progression, and have a limited ability to repair wounds. In recent years, with the increasing understanding of the function of FGF, more and more researchers have been applying FGF-1, FGF-2, FGF-4, FGF-7, FGF-21 and FGF-23 topically to DFU with good therapeutic effects. This review elaborates on the recently developed FGF family members, outlining their mechanisms of action, and describing their potential therapeutics in DFU.

The Immune Functions of Keratinocytes in Skin Wound Healing

As the most dominant cell type in the skin, keratinocytes play critical roles in wound repair not only as structural cells but also exerting important immune functions. This review focuses on the communications between keratinocytes and immune cells in wound healing, which are mediated by various cytokines, chemokines, and extracellular vesicles. Keratinocytes can also directly interact with T cells via antigen presentation. Moreover, keratinocytes produce antimicrobial peptides that can directly kill the invading pathogens and contribute to wound repair in many aspects. We also reviewed the epigenetic mechanisms known to regulate keratinocyte immune functions, including histone modifications, non-protein-coding RNAs (e.g., microRNAs, and long noncoding RNAs), and chromatin dynamics. Lastly, we summarized the current evidence on the dysregulated immune functions of keratinocytes in chronic nonhealing wounds. Based on their crucial immune functions in skin wound healing, we propose that keratinocytes significantly contribute to the pathogenesis of chronic wound inflammation. We hope this review will trigger an interest in investigating the immune roles of keratinocytes in chronic wound pathology, which may open up new avenues for developing innovative wound treatments.

Bilayered Fibrin-Based Electrospun-Sprayed Scaffold Loaded with Platelet Lysate Enhances Wound Healing in a Diabetic Mouse Model

The present study examined the effects of a bilayered fibrin/poly(ether)urethane scaffold loaded with platelet lysate by a combination of electrospinning and spray, phase-inversion method for wound healing. In particular, the poly(ether)urethane layer was obtained using by a spray phase-inversion method and the fibrin fibers network were loaded with platelet lysate by electrospinning. The kinetics release and the bioactivity of growth factors released from platelet lysate-scaffold were investigated by ELISA and cell proliferation test using mouse fibroblasts, respectively. The in-vitro experiments demonstrated that a bilayered fibrin/poly(ether)urethane scaffold loaded with platelet lysate provides a sustained release of bioactive platelet-derived growth factors. The effect of a bilayered fibrin/poly(ether)urethane scaffold loaded with platelet lysate on wound healing in diabetic mouse (db/db) was also investigated. The application of the scaffold on full-thickness skin wounds significantly accelerated wound closure at day 14 post-surgery when compared to scaffold without platelet lysates or commercially available polyurethane film, and at the same level of growth factor-loaded scaffold. Histological analysis demonstrated an increased re-epithelialization and collagen deposition in platelet lysate and growth factor loaded scaffolds. The ability of bilayered fibrin/poly(ether)urethane scaffold loaded with platelet lysate to promote in-vivo wound healing suggests its usefulness in clinical treatment of diabetic ulcers.

Challenges and New Therapeutic Approaches in the Management of Chronic Wounds

Chronic non-healing wounds are estimated to cost the US healthcare $28-$31 billion per year. Diabetic ulcers, arterial and venous ulcers, and pressure ulcers are some of the most common types of chronic wounds. The burden of chronic wounds continues to rise due to the current epidemic of obesity and diabetes and the increase in elderly adults in the population who are more vulnerable to chronic wounds than younger individuals. This patient population is also highly vulnerable to debilitating infections caused by opportunistic and multi-drug resistant pathogens. Reduced microcirculation, decreased availability of cytokines and growth factors that promote wound closure and healing, and infections by multi-drug resistant and biofilm forming microbes are some of the critical factors that contribute to the development of chronic non-healing wounds. This review discusses novel approaches to understand chronic wound pathology and methods to improve chronic wound care, particularly when chronic wounds are infected by multi-drug resistant, biofilm forming microbes.

The use of irradiated amnion dressing for the treatment of antibiotic-disinfected skin ulcer

Skin ulcers are non-healed wounds caused by inflammation of epidermis up to the dermis, which causes pain and limits body movements, significantly reducing quality of life. Amniotic membrane is a placental collagenous biomaterial with many biological and mechanical properties important for tissue engineering and regenerative medicine. The aim of this work is to evaluate the efficacy of topical antibiotic washing followed with irradiated human amniotic membrane (iHAM) dressing for treating five different types of ulcers. The current study included 15 patients who were recruited from the outpatient clinic of the Egyptian Atomic Energy Authority. Follow up of all treated cases that completed the regimen was up to 3 months. The clinical progression of all treated ulcers was quantitatively evaluated by computerized estimation of the wound size reduction based on 3D image analysis. All cases in this study showed great outcomes within several weeks of treatment depending on wound infection, ulcer depth and size, period of healing disorder, age, blood glycemia, and other clinical criteria. Patients' questionnaires revealed that pain was controlled by the first time of treatment. After 1 week post-treatment, granulation tissue was generated and observed in all patients, and all microbial colonies have been eliminated from wounds with previous infection. The current study indicated that the dressing of ulcers with iHAM induces fast healing without complication.

Treatment of hard-to-heal leg ulcers with hyaluronic acid, sodium alginate and negative pressure wound therapy

OBJECTIVE

Hard-to-heal lower extremity ulcer is a common healthcare problem and can lead to a poor quality of life (QoL). Despite the advances in wound care, conventional therapies, such as necrotic tissue debridement, cleansing, treatment of infection and local treatment with dressing application are still considered the standard of care in patients with hard-to-heal leg ulcers. However, managing hard-to-heal ulcers that do not respond well to these methods has led to new treatment strategies. In this study, the effects of hyaluronic acid (HA) and sodium alginate (SA), combined with negative pressure wound therapy (NPWT), in patients with hard-to-heal leg ulcers are evaluated.

METHOD

Patients with hard-to-heal lower extremity ulcers were treated with HA-SA combined with NPWT (HA-SA-NWPT, n=11), or conventional therapy (n=14), between June 2014 and September 2015. Demographics, comorbidities, time to complete healing and change in wound area were recorded and compared.

RESULTS

A total of 25 patients took part. Complete healing was achieved in 63.6% (n=7) of the patients in the HA-SA with NPWT group, compared with 14.3% (n=2) of the patients in the conventional therapy group (p=0.017). The mean decrease in wound size was significantly higher in the HA-SA-NPWT group than in the conventional therapy group (73.8% versus 34.8%, respectively, p=0.029). Despite a shorter healing period in the HA-SA-NPWT group than in the conventional group, no statistically significant difference was found between groups for time to complete healing (37 days versus 55 days, respectively).

CONCLUSION

These results demonstrate that the combination of HA-SA-NPWT is a promising treatment for decreasing the healing time and increasing the success rate by their synergistic effect on wound healing in hard-to-heal lower extremity ulcers. However, further studies with a larger number of patients are needed to confirm the results.

κ-carrageenan-C-phycocyanin based smart injectable hydrogels for accelerated wound recovery and real-time monitoring

Wound healing remains a healthcare challenge in patients suffering from grave tissue damage due to burn injuries and severe medical conditions like diabetes and ischemia. A repeated wound dressing in such cases leads to tissue damage, which could further inflate the wound healing. It is also challenging to analyze the depth of wound bed in these conditions, which could affect the recovery period. To address this need, we have developed an injectable hydrogel from natural polysaccharide κ-carrageenan and a pigmented protein C-phycocyanin. C-phycocyanin has wound healing, antimicrobial, antioxidant and anti-inflammatory properties along with the In-vivo fluorescence imaging ability. Gelling property of κ-carrageenan could be utilized along with C-phycocyanin as an injectable and regenerative wound dressings matrix to monitor wound healing in real-time without upsetting the healing process. The hydrogel presented herein was built from ionic crosslinking of κ-carrageenan monomers along with C-phycocyanin, which provides an interconnected network of porous material with hydrophilic surface and mechanical stiffness. This porosity allows nutrients transportation and gaseous exchange across the wound healing site for the proliferation of various cells. Hydrogel material enhances the proliferation of dermal fibroblasts in vitro without inducing inflammation along with reducing the blood clotting time with no haemolysis. We have found that κ-carrageenan-C-phycocyanin (κ-CRG-C-Pc) hydrogel not only exhibit superior haemostatic capabilities in traumatic injury condition but also provide support for rapid wound healing. Overall, these findings demonstrate the potential of κ-carrageenan-C-phycocyanin hydrogels as a wound-healing and imaging platform towards accelerating tissue repair and real-time monitoring. STATEMENT OF SIGNIFICANCE: Blood clotting and inflammation are the most crucial stages of wound healing along with appropriate monitoring of the healing process. Thus, there is a need of system that could provide point-to-point care and monitoring in this multistage process. Here, we have introduced a self healing, injectable hydrogel system with in vivo imaging abilities from κ-carragenan and C-phycocyanin. C-phycocyanin improves the stability of κ-carragenan matrix and provide support to cellular adhesion, proliferation, and migration. Its anti-inflammatory response and rapid blood clotting ability further empower its applicability in critical medical conditions and wound recovery.

Role of microRNA-21 and Its Underlying Mechanisms in Inflammatory Responses in Diabetic Wounds

A central feature of diabetic wounds is the persistence of chronic inflammation, which is partly due to the prolonged presence of pro-inflammatory (M1) macrophages in diabetic wounds. Persistence of the M1 macrophage phenotype and failure to transition to the regenerative or pro-remodeling (M2) macrophage phenotype plays an indispensable role in diabetic wound impairment; however, the mechanism underlying this relationship remains unclear. Recently, microRNAs have been shown to provide an additional layer of regulation of gene expression. In particular, microRNA-21 (miR-21) is essential for an inflammatory immune response. We hypothesize that miR-21 plays a role in regulating inflammation by promoting M1 macrophage polarization and the production of reactive oxygen species (ROS). To test our hypothesis, we employed an in vivo mouse skin wound model in conjunction with an in vitro mouse model to assess miR-21 expression and macrophage polarization. First, we found that miR-21 exhibits a distinct expression pattern in each phase of healing in diabetic wounds. MiR-21 abundance was higher during early and late phases of wound repair in diabetic wounds, while it was significantly lower in the middle phase of wounding (at days 3 and 7 following wounding). In macrophage cells, M1 polarized macrophages exhibited an upregulation of miR-21, as well as the M1 and pro-inflammatory markers IL-1b, TNFa, iNos, IL-6, and IL-8. Overexpression of miR-21 in macrophage cells resulted in an upregulation of miR-21 and also increased expression of the M1 markers IL-1b, TNFa, iNos, and IL-6. Furthermore, hyperglycemia induced NOX2 expression and ROS production through the HG/miR-21/PI3K/NOX2/ROS signaling cascade. These findings provide evidence that miR-21 is involved in the regulation of inflammation. Dysregulation of miR-21 may explain the abnormal inflammation and persistent M1 macrophage polarization seen in diabetic wounds.

Vibrational stress affects extracellular signal-regulated kinases activation and cytoskeleton structure in human keratinocytes

As the outermost organ, the skin can be damaged following injuries such as wounds and bacterial or viral infections, and such damage should be rapidly restored to defend the body against physical, chemical, and microbial assaults. However, the wound healing process can be delayed or prolonged by health conditions, including diabetes mellitus, venous stasis disease, ischemia, and even stress. In this study, we developed a vibrational cell culture model and investigated the effects of mechanical vibrations on human keratinocytes. The HaCaT cells were exposed to vibrations at a frequency of 45 Hz with accelerations of 0.8g for 2 h per day. The applied mechanical vibration did not affect cell viability or cell proliferation. Cell migratory activity did increase following exposure to vibration, but the change was not statistically significant. The results of immunostaining (F-actin), western blot (ERK1/2), and RT-qPCR (FGF-2, PDGF-B, HB-EGF, TGF-β1, EGFR, and KGFR) analyses demonstrated that the applied vibration resulted in rearrangement of the cytoskeleton, leading to activation of ERK1/2, one of the MAPK signaling pathways, and upregulation of the gene expression levels of HB-EGF and EGFR. The results suggest that mechanical vibration may have wound healing potential and could be used as a mechanical energy-based treatment for enhancing wound healing efficiency.

Impaired Neovascularization in Aging

Significance: The skin undergoes an inevitable degeneration as an individual ages. As intrinsic and extrinsic factors degrade the structural integrity of the skin, it experiences a critical loss of function and homeostatic stability. Thus, aged skin becomes increasingly susceptible to injury and displays a prolonged healing process. Recent Advances: Several studies have found significant differences during wound healing between younger and older individuals. The hypoxia-inducible factor 1-alpha (HIF-1α) signaling pathway has recently been identified as a major player in wound healing. Hypoxia-inducible factors (HIFs) are pleiotropic key regulators of oxygen homeostasis. HIF-1α is essential to neovascularization through its regulation of cytokines, such as SDF-1α (stromal cell-derived factor 1-alpha) and has been shown to upregulate the expression of genes important for a hypoxic response. Prolyl hydroxylase domain proteins (PHDs) and factor inhibiting HIF effectively block HIF-1α signaling in normoxia through hydroxylation, preventing the signaling cascade from activating, leading to impaired tissue survival. Critical Issues: Aged wounds are a major clinical burden, resisting modern treatment and costing millions in health care each year. At the molecular level, aging has been shown to interfere with PHD regulation, which in turn prevents HIF-1α from activating gene expression, ultimately leading to impaired healing. Other studies have identified loss of function in cells during aging, impeding processes such as angiogenesis. Future Directions: An improved understanding of the regulation of molecular mediators, such as HIF-1α and PHD, will allow for manipulation of the various factors underlying delayed wound healing in the aged. The findings highlighted in this may facilitate the development of potential therapeutic approaches involved in the alteration of cellular dynamics and aging.

Investigation of the effects of thrombocyte-rich plasma, systemic ozone and hyperbaric oxygen treatment on intraoral wound healing in rats: experimental study

OBJECTIVE

In this study, it was aimed to evaluate and compare biochemical and histopathological effects of platelet-rich plasma (PRP), ozone and hyperbaric oxygen (HBO) on wound healing which was formed experimentally in oral cavity of rats.

MATERIALS AND METHODS

In this study, thirty-six Wistar Hannover rats with weight of 250-350 g, fed with standard feeds, were anesthetized to create intraoral wound on the hard palate. Rats were divided into four groups as the following: control group, PRP, HBO and Ozone groups. 0.1 ml of PRP was injected on the wound edges of each rat in the PRP group on days 1, 3 and 7. Each rat in the ozone group was systemically injected with 2.3-3.0 ml ozone gas on the 1st, 3rd and 7th days. The wounds of the rats in the control group were not performed anything. The rats in the HBO group were placed in the HBO pressure chamber and were treated with one session (2 h for each session) of 100% oxygen each day for 7 days. Rats in all groups were killed on the 15th day and the hard palates were excised for histopathological examination. Inflammation severity, neovascularization, fibroblast proliferation, collagen density and epithelization were evaluated.

RESULTS

The rate of intense wound closure (epithelialization intensity) was significantly higher in all the three treatment groups, the PRP group was the highest, than in the control group (p < 0.05). Fibroblast proliferation level was higher in PRP group (p < 0.05), followed by ozone, HBO and control groups, respectively. Histologically, inflammation was significantly higher in the control group than the treatment groups (p < 0.05). For the treatment groups; it was lowest in the PRP group, followed by the ozone and HBO groups, respectively. The rates of angiogenesis and collagenization were significantly higher in all the three treatment groups, the PRP group was the highest, than in the control group (p < 0.05). In this study, no significance difference was found between the groups in terms of blood glucose levels (p = 0.21).

CONCLUSION

In this study, all three treatment modalities were found to be effective in wound healing, and PRP was found to be more effective than the others.

Tissue Engineering Approaches for Enamel, Dentin, and Pulp Regeneration: An Update

Stem/progenitor cells are undifferentiated cells characterized by their exclusive ability for self-renewal and multilineage differentiation potential. In recent years, researchers and investigations explored the prospect of employing stem/progenitor cell therapy in regenerative medicine, especially stem/progenitor cells originating from the oral tissues. In this context, the regeneration of the lost dental tissues including enamel, dentin, and the dental pulp are pivotal targets for stem/progenitor cell therapy. The present review elaborates on the different sources of stem/progenitor cells and their potential clinical applications to regenerate enamel, dentin, and the dental pulpal tissues.