Wound healing related agents: Ongoing research and perspectives

Chitosan-based injectable hydrogel with multifunction for wound healing: A critical review

Different types of clinical wounds are difficult to treat while infected by bacteria. Wound repair involves multiple cellular and molecular interactions, which is a complicated process. However, wound repair often suffers from abnormal cellular functions or pathways that result in unavoidable side effects, so there is an urgent need for a material that can heal wounds quickly and with few side effects. Based on these needs, hydrogels with injectable properties have been confirmed to be able to undergo self-healing, which provides favorable conditions for wound healing. Notably, as a biopolymer with excellent easy-to-modify properties from a wide range of natural sources, chitosan can be used to prepare injectable hydrogel with multifunction for wound healing because of its outstanding flowability and injectability. Especially, chitosan-based hydrogels with marked biocompatibility, non-toxicity, and bio-adhesion properties are ideal for facilitating wound healing. In this review, the characteristics and healing mechanisms of different wounds are briefly summarized. In addition, the preparation and characterization of injectable chitosan hydrogels in recent years are classified. Additionally, the bioactive properties of this type of hydrogel in vitro and in vivo are demonstrated, and future trend in wound healing is prospected.

Mussel inspired 3D elastomer enabled rapid calvarial bone regeneration through recruiting more osteoprogenitors from the dura mater

Currently, the successful healing of critical-sized calvarial bone defects remains a considerable challenge. The immune response plays a key role in regulating bone regeneration after material grafting. Previous studies mainly focused on the relationship between macrophages and bone marrow mesenchymal stem cells (BMSCs), while dural cells were recently found to play a vital role in the calvarial bone healing. In this study, a series of 3D elastomers with different proportions of polycaprolactone (PCL) and poly(glycerol sebacate) (PGS) were fabricated, which were further supplemented with polydopamine (PDA) coating. The physicochemical properties of the PCL/PGS and PCL/PGS/PDA grafts were measured, and then they were implanted as filling materials for 8 mm calvarial bone defects. The results showed that a matched and effective PDA interface formed on a well-proportioned elastomer, which effectively modulated the polarization of M2 macrophages and promoted the recruitment of dural cells to achieve full-thickness bone repair through both intramembranous and endochondral ossification. Single-cell RNA sequencing analysis revealed the predominance of dural cells during bone healing and their close relationship with macrophages. The findings illustrated that the crosstalk between dural cells and macrophages determined the vertical full-thickness bone repair for the first time, which may be the new target for designing bone grafts for calvarial bone healing.

Microneedle System with Biomarker-Activatable Chromophore as Both Optical Imaging Probe and Anti-bacterial Agent for Combination Therapy of Bacterial-Infected Wounds and Outcome Monitoring

Wounds infected with bacteria, if left untreated, have the potential to escalate into life-threatening conditions, such as sepsis, which is characterized by widespread inflammation and organ damage. A comprehensive approach to treating bacterial-infected wounds, encompassing the control of bacterial infection, biofilm eradication, and inflammation regulation, holds significant importance. Herein, a microneedle (MN) patch (FM@ST MN) has been developed, with silk fibroin (SF) and tannic acid-based hydrogel serving as the matrix. Encapsulated within the MNs are the AIEgen-based activatable probe (FQ-H2O2) and the NLRP3 inhibitor MCC950, serving as the optical reporter/antibacterial agent and the inflammation regulator, respectively. When applied onto bacterial-infected wounds, the MNs in FM@ST MN penetrate bacterial biofilms and gradually degrade, releasing FQ-H2O2 and MCC950. The released FQ-H2O2 responds to endogenously overexpressed reactive oxygen species (H2O2) at the wound site, generating a chromophore FQ-OH which emits noticeable NIR-II fluorescence and optoacoustic signals, enabling real-time imaging for outcome monitoring; and this chromophore also exhibits potent antibacterial capability due to its dual positive charges and shows negligible antibacterial resistance. However, the NLRP3 inhibitor MCC950, upon release, suppresses the activation of NLRP3 inflammasomes, thereby mitigating the inflammation triggered by bacterial infections and facilitating wound healing. Furthermore, SF in FM@ST MN aids in tissue repair and regeneration by promoting the proliferation of epidermal cells and fibroblasts and collagen synthesis. This MN system, free from antibiotics, holds promise as a solution for treating and monitoring bacterially infected wounds without the associated risk of antimicrobial resistance.

The transformation of multifunctional bio-patch to hydrogel on skin wounds for efficient scarless wound healing

Hydrogels have been widely used in various biomedical applications, including skin regeneration and tissue repair. However, the capability of certain hydrogels to absorb exudate or blood from surrounding wounds, coupled with the challenge in their long-term storage to prevent bacterial growth, can pose limitations to their efficacy in biological applications. To address these challenges, the development of a multifunctional aloin-arginine-alginate (short for 3A) bio-patch capable of transforming into a hydrogel upon absorbing exudate or blood from neighboring wounds for cutaneous regeneration is proposed. The 3A bio-patch exhibits outstanding features, including an excellent porous structure, swelling properties, and biodegradability. These characteristics allow for the rapid absorption of wound exudates and subsequent transformation into a hydrogel that is suitable for treating skin wounds. Furthermore, the 3A bio-patch exhibits remarkable antibacterial and anti-inflammatory properties, leading to accelerated wound healing and scarless repair in vivo. This study presents a novel approach to the development of cutaneous wound dressing materials.

Electrospun membranes chelated by metal magnesium ions enhance pro-angiogenic activity and promote diabetic wound healing

Diabetic wounds, resulting from skin atrophy due to localized ischemia and hypoxia in diabetic patients, lead to chronic pathological inflammation and delayed healing. Using electrospinning technology, we developed magnesium ion-chelated nanofiber membranes to explore their efficacy in antibacterial, anti-inflammatory, and angiogenic applications for wound healing. These membranes are flexible and elastic, resembling native skin tissue, and possess good hydrophilicity for comfortable wound bed contact. The mechanical properties of nanofiber membranes are enhanced by the chelation of magnesium ions (Mg2+), which also facilitates a long-term slow release of Mg2+. The cytocompatibility of the nanofibrous membranes is influenced by their Mg2+ content: lower levels encourage the proliferation of fibroblasts, endothelial cells, and macrophages, while higher levels are inhibitory. In a diabetic rat model, magnesium ion-chelated nanofibrous membranes effectively reduced early wound inflammation and notably accelerated wound healing. This study highlights the potential of magnesium ion-chelated nanofiber membranes in treating diabetic wounds.

Protein/polysaccharide-based hydrogels loaded probiotic-mediated therapeutic systems: A review

The natural characteristics of protein/polysaccharide-based hydrogels, as a potential drug delivery platform, have attracted extensive attention. Probiotics have attracted renewed interest in drug research because of their beneficial effects on host health. The idea of using probiotics loaded on protein/polysaccharide-based hydrogels as potential drugs to treat different diseases has been put forward and shows great prospects. Based on this, in this review, we highlight the design strategy of hydrogels loaded probiotic-mediated therapy systems and review the potential diseases that have been proved to be treatable in the laboratory, including promoting wound healing and improving intestinal health and vaginal health, and discuss the challenges existing in the current design.

SOX family transcription factors as therapeutic targets in wound healing: A comprehensive review

The SOX family plays a vital role in determining the fate of cells and has garnered attention in the fields of cancer research and regenerative medicine. It also shows promise in the study of wound healing, as it actively participates in the healing processes of various tissues such as skin, fractures, tendons, and the cornea. However, our understanding of the mechanisms behind the SOX family's involvement in wound healing is limited compared to its role in cancer. Gaining insight into its role, distribution, interaction with other factors, and modifications in traumatized tissues could provide valuable new knowledge about wound healing. Based on current research, SOX2, SOX7, and SOX9 are the most promising members of the SOX family for future interventions in wound healing. SOX2 and SOX9 promote the renewal of cells, while SOX7 enhances the microvascular environment. The SOX family holds significant potential for advancing wound healing research. This article provides a comprehensive review of the latest research advancements and therapeutic tools related to the SOX family in wound healing, as well as the potential benefits and challenges of targeting the SOX family for wound treatment.

Synergistic effects of electroactive antibacterial material and electrical stimulation in enhancing skin tissue regeneration: A next-generation dermal wound dressing

OBJECTIVE

We aimed to develop an electroactive antibacterial material for the treatment of skin wound diseases.

METHOD

To this aim, we modified chitosan (CS), a biocompatible polymer, by coupling it with graphene (rGO) and an antimicrobial polypeptide DOPA-PonG1. The material's effect on skin injury healing was studied in combination with external electrical stimulation (EEM). The structure, surface composition, and hydrophilicity of the modified CS materials were evaluated using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and contact angle measurements. We studied NIH3T3 cells cultured with modified materials and subjected to EEM to assess viability, adhesion, and tissue repair-related gene expression.

RESULTS

SEM data demonstrated that rGO was distributed uniformly on the surface of the CS material, increasing surface roughness, and antimicrobial peptides had minimal impact on surface morphology. FTIR confirmed the uniform distribution of rGO and antibacterial peptides on the material surface. Both rGO and DOPA-PonG1 enhanced the hydrophilicity of CS materials, with rGO also improving tensile strength. The dual modification of CS with rGO and DOPA-PonG1 synergistically increased antibacterial efficacy. Cellular events and gene expression relevant to tissue repair process were enhanced by these modifications. Furthermore, EEM accelerated epidermal regeneration more than the material alone. In a rat skin wound model, DOPA-PonG1@CS/rGO dressing combined with electrical stimulation exhibited accelerated healing of skin defect.

CONCLUSION

Overall, our results demonstrate that CS materials modified with rGO and DOPA-PonG1 have increased hydrophilicity, antibacterial characteristics, and tissue regeneration capacities. This modified material in conjunction with EEM hold promise for the clinical management for dermal wounds.

Stem cell-derived exosomes: emerging therapeutic opportunities for wound healing

Wound healing is a dynamic and highly sequential process involving a series of overlapping spatial and temporal phases, including hemostasis, inflammation, proliferation, and tissue remodeling. Mesenchymal stem cells (MSCs) are multipotent stem cells with self-renewal, multidirectional differentiation potential, and paracrine regulation. Exosomes are subcellular vesicular components 30-150 nm in size and are novel carriers of intercellular communication in regulating the biological behaviors of skin cells. Compared to MSCs, MSC-derived exosomes (MSC-exos) possess lower immunogenicity, easy storage, and highly effective biological activity. MSC-exos, mainly derived from adipose-derived stem cells (ADSCs), bone marrow-derived MSCs (BMSCs), human umbilical cord MSCs (hUC-MSCs), and other stem cell types, play a role in shaping the activity of fibroblasts, keratinocytes, immune cells, and endothelial cells in diabetic wounds, inflammatory wound repair, and even wound-related keloid formation. Therefore, this study focuses on the specific roles and mechanisms of different MSC-exos in wound healing, as well as the current limitations and various perspectives. Deciphering the biological properties of MSC-exos is crucial to providing a promising cell-free therapeutic tool for wound healing and cutaneous regeneration.

Multifunctional Bletilla striata polysaccharide/copper/peony leaf sponge for the full-stage wound healing

Conventional wound dressings fail to satisfy the requirements and needs of wounds in various stages. It is challenging to develop a multifunctional dressing that is hemostatic, antibacterial, anti-inflammatory, and promotes wound healing. Therefore, this study aimed to develop a multifunctional sponge dressing for the full-stage wound healing based on copper and two natural products, Bletilla striata polysaccharide (BSP) and peony leaf extract (PLE). The developed BSP-Cu-PLE sponges were characterized by SEM, XRD, FTIR, and XPS to assess micromorphology and elemental composition. Their properties and bioactivities were also verified by the further experiments, whereby the findings revealed that the BSP-Cu-PLE sponges had improved water absorption and porosity while exhibiting excellent antioxidative, biocompatible, and biodegradable properties. Moreover, the antibacterial test revealed that BSP-Cu-PLE sponges had superior antibacterial activity against S. aureus and E. coli. Furthermore, the hemostatic activity of BSP-Cu-PLE sponges was significantly enhanced in a rat liver trauma model. Most notably, further studies have demonstrated that the BSP-Cu-PLE sponges could significantly (p < 0.05) accelerate the healing process of skin wounds by stimulating collagen deposition, promoting angiogenesis, and decreasing inflammatory cells. In summary, the BSP-Cu-PLE sponges could provide a new strategy for application in clinical setting for full-stage wound healing.

Why traditional herbal medicine promotes wound healing: Research from immune response, wound microbiome to controlled delivery

Impaired wound healing in chronic wounds has been a significant challenge for clinicians and researchers for decades. Traditional herbal medicine (THM) has a long history of promoting wound healing, making them culturally accepted and trusted by a great number of people in the world. However, for a long time, the understanding of herbal medicine has been limited and incomplete, particularly in the allopathic medicine-dominated research system. The therapeutic effects of individual components isolated from THM are found less pronounced compared to synthetic chemical medicine, and the clinical efficacy is always inferior to herbs. In the present article, we review and discuss underlying mechanisms of the skin microbiome involved in the wound healing process; THM in regulating immune responses and commensal microbiome. We additionally propose few pioneer ideas and studies in the development of therapeutic strategies for controlled delivery of herbal medicine. This review aims to promote wound care with a focus on wound microbiome, immune response, and topical drug delivery systems. Finally, future development trends, challenges, and research directions are discussed.

Colonizing microbiota is associated with clinical outcomes in diabetic wound healing

With the development of society and the improvement of life quality, more than 500 million people are affected by diabetes. More than 10 % of people with diabetes will suffer from diabetic wounds, and 80 % of diabetic wounds will reoccur, so the development of new diabetic wound treatments is of great importance. The development of skin microbe research technology has gradually drawn people's attention to the complex relationship between microbes and diabetic wounds. Many studies have shown that skin microbes are associated with the outcome of diabetic wounds and can even be used as one of the indicators of wound prognosis. Skin microbes have also been found to have the potential to treat diabetic wounds. The wound colonization of different bacteria can exert opposing therapeutic effects. It is necessary to fully understand the skin microbes in diabetic wounds, which can provide valuable guidance for clinical diabetic wound treatment.

Beneficial Effects of Dinitrosyl Iron Complexes on Wound Healing Compared to Commercial Nitric Oxide Plasma Generator

Nitric oxide (NO) is a gaseous molecule which plays a key role in wound healing. Previously, we identified the optimal conditions for wound healing strategies using NO donors and an air plasma generator. The aim of this study was to compare the wound healing effects of binuclear dinitrosyl iron complexes with glutathione (B-DNIC-GSH) and NO-containing gas flow (NO-CGF) at their optimal NO doses (0.04 mmol for B-DNIC-GSH and 1.0 mmol for NO-CGF per 1 cm²) in a rat full-thickness wound model over a 3-week period. Excised wound tissues were studied by light and transmission electron microscopy and immunohistochemical, morphometrical and statistical methods. Both treatments had an identical stimulating impact on wound healing, which indicated a higher dosage effectiveness of B-DNIC-GSH compared to the NO-CGF. B-DNIC-GSH spray application reduced inflammation and promoted fibroblast proliferation, angiogenesis and the growth of granulation tissue during the first 4 days after injury. However, prolonged NO spray effects were mild compared to NO-CGF. Future studies should determine the optimal B-DNIC-GSH solution course for a more effective wound healing stimulation.

Schinus terebinthifolius Leaf Lectin (SteLL) Reduces the Bacterial and Inflammatory Burden of Wounds Infected by Staphylococcus aureus Promoting Skin Repair

Staphylococcus aureus is commonly found in wound infections where this pathogen impairs skin repair. The lectin isolated from leaves of Schinus terebinthifolius (named SteLL) has antimicrobial and antivirulence action against S. aureus. This study evaluated the effects of topical administration of SteLL on mice wounds infected by S. aureus. Seventy-two C57/BL6 mice (6−8 weeks old) were allocated into four groups: (i) uninfected wounds; (ii) infected wounds, (iii) infected wounds treated with 32 µg/mL SteLL solution; (iv) infected wounds treated with 64 µg/mL SteLL solution. The excisional wounds (64 mm2) were induced on the dorsum and infected by S. aureus 432170 (4.0 × 106 CFU/wound). The daily treatment started 1-day post-infection (dpi). The topical application of both SteLL concentrations significantly accelerated the healing of S. aureus-infected wounds until the 7th dpi, when compared to untreated infected lesions (reductions of 1.95−4.55-fold and 1.79−2.90-fold for SteLL at 32 µg/mL and 64 µg/mL, respectively). The SteLL-based treatment also amended the severity of wound infection and reduced the bacterial load (12-fold to 72-fold for 32 µg/mL, and 14-fold to 282-fold for 64 µg/mL). SteLL-treated wounds show higher collagen deposition and restoration of skin structure than other groups. The bacterial load and the levels of inflammatory markers (IL-6, MCP-1, TNF-α, and VEGF) were also reduced by both SteLL concentrations. These results corroborate the reported anti-infective properties of SteLL, making this lectin a lead candidate for developing alternative agents for the treatment of S. aureus-infected skin lesions.

A Novel Peptide from Polypedates megacephalus Promotes Wound Healing in Mice

Amphibian skin contains wound-healing peptides, antimicrobial peptides, and insulin-releasing peptides, which give their skin a strong regeneration ability to adapt to a complex and harsh living environment. In the current research, a novel wound-healing promoting peptide, PM-7, was identified from the skin secretions of Polypedates megacephalus, which has an amino acid sequence of FLNWRRILFLKVVR and shares no structural similarity with any peptides described before. It displays the activity of promoting wound healing in mice. Moreover, PM-7 exhibits the function of enhancing proliferation and migration in HUVEC and HSF cells by affecting the MAPK signaling pathway. Considering its favorable traits as a novel peptide that significantly promotes wound healing, PM-7 can be a potential candidate in the development of novel wound-repairing drugs.

A Biomimetic Smart Nanoplatform as “Inflammation Scavenger” for Regenerative Therapy of Periodontal Tissue

Introduction

The functional reconstruction of periodontal tissue defects remains a clinical challenge due to excessive and prolonged host response to various endogenous and exogenous pro-inflammatory stimuli. Thus, a biomimetic nanoplatform with the capability of modulating inflammatory response in a microenvironment-responsive manner is attractive for regenerative therapy of periodontal tissue.

Methods

Herein, a facile and green design of engineered bone graft materials was developed by integrating a biomimetic apatite nanocomposite with a smart-release coating, which could realize inflammatory modulation by “on-demand” delivery of the anti-inflammatory agent through a pH-sensing mechanism.

Results

In vitro and in vivo experiments demonstrated that this biocompatible nanoplatform could facilitate the clearance of reactive oxygen species in human periodontal ligament stem cells under inflammatory conditions via inhibiting the production of endogenous proinflammatory mediators, in turn contributing to the enhanced healing efficacy of periodontal tissue. Moreover, this system exhibited effective antimicrobial activity against common pathogenic bacteria in the oral cavity, which is beneficial for the elimination of exogenous pro-inflammatory factors from bacterial infection during healing of periodontal tissue.

Conclusion

The proposed strategy provides a versatile apatite nanocomposite as a promising “inflammation scavenger” and propels the development of intelligent bone graft materials for periodontal and orthopedic applications.

Multifunctional all-in-one adhesive hydrogel for the treatment of perianal infectious wounds

Postoperative wound of perianal infectious disease represents a common but unique refractory wound in clinical practice. The reasons that hinder the wound healing process include not only the severe bacterial infection of the wound itself and the narrow and deep shape of the wound, but also its frequent bacterial contact. Therefore, the development of biofunctional dressings to aid in therapy is essential. In this study, we synthesized a new type of dressing comprising a hydrogel host based on the Schiff base principle and catechol groups between polydopamine, oxidized dextran, and quaternized chitosan, and then loaded it with traditional Chinese medicine molecules. These formed an integrated hydrogel for accelerated wound repair in a perianal infection model. The prepared hydrogels exhibited excellent wet tissue adhesion, antifouling, morphological variability, suitable swelling properties, and complete degradability, as well as remarkable contact antibacterial ability and the ability to rapidly scavenge free radicals. Hemostatic experiments showed excellent hemostatic properties, as the integrated hydrogel could instantly gel to seal the hemorrhage. Hemocompatibility and in vitro cell experiments showed that the integrated hydrogel had good biosafety and significantly promoted cell proliferation, which in turn accelerated the repair of infected whole cortexes in rats. A histomorphological evaluation showed that the integrated hydrogel promoted the recovery of normal anatomical tissue in rats by promoting the formation of collagen fibers and inhibiting inflammation. The results showed that this multifunctional integrated hydrogel has great potential for the treatment of continuously infected skin regeneration, providing a promising therapeutic strategy for postoperative wound healing in perianal infectious diseases.

The Expression and Function of lincRNA-154324 and the Adjoining Protein-Coding Gene vmp1 in the Caudal Fin Regeneration of Zebrafish

Caudal fin regeneration is regulated by a variety of mechanisms, but the role of long non-coding RNA (lncRNA) has rarely been studied. The present study aimed to describe the landscape of lncRNAs during caudal fin regeneration using whole transcriptome sequencing, and then to conduct a functional study on the target lncRNAs using real-time fluorescent quantitative PCR (RT-qPCR), in situ hybridization, and the CRISPR/Cas9 method for lncRNA gene knockout. The results of the transcriptome sequencing showed that a total of 381 lncRNAs were differentially expressed, among which ENSDART00000154324 (lincRNA-154324) was found to be highly related to caudal fin regeneration, and thus it was chosen as the target lncRNA for the subsequent functional study. The results regarding the temporal and spatial expression of lincRNA-154324 and the gene knockout results from CRISPR/Cas9 indicated that lincRNA-154324 is involved in the caudal fin regeneration of zebrafish. Importantly, we serendipitously discovered that the cis correlation coefficient between lincRNA-154324 and its neighboring gene vacuole membrane protein 1 (vmp1) is extremely high, and they are essential for the process of caudal fin regeneration. Moreover, studies have found that vmp1 plays an important role in protein secretion, organelle formation, multicellular development, and autophagy. Collectively, our result may provide a framework for the identification and analysis of lncRNAs involved in the regeneration of the zebrafish caudal fin.

Neuroinflammatory Gene Expression Analysis Reveals Pathways of Interest as Potential Targets to Improve the Recording Performance of Intracortical Microelectrodes

Intracortical microelectrodes are a critical component of brain-machine interface (BMI) systems. The recording performance of intracortical microelectrodes used for both basic neuroscience research and clinical applications of BMIs decreases over time, limiting the utility of the devices. The neuroinflammatory response to the microelectrode has been identified as a significant contributing factor to its performance. Traditionally, pathological assessment has been limited to a dozen or so known neuroinflammatory proteins, and only a few groups have begun to explore changes in gene expression following microelectrode implantation. Our initial characterization of gene expression profiles of the neuroinflammatory response to mice implanted with non-functional intracortical probes revealed many upregulated genes that could inform future therapeutic targets. Emphasis was placed on the most significant gene expression changes and genes involved in multiple innate immune sets, including Cd14, C3, Itgam, and Irak4. In previous studies, inhibition of Cluster of Differentiation 14 (Cd14) improved microelectrode performance for up to two weeks after electrode implantation, suggesting CD14 can be explored as a potential therapeutic target. However, all measures of improvements in signal quality and electrode performance lost statistical significance after two weeks. Therefore, the current study investigated the expression of genes in the neuroinflammatory pathway at the tissue-microelectrode interface in Cd14-/- mice to understand better how Cd14 inhibition was connected to temporary improvements in recording quality over the initial 2-weeks post-surgery, allowing for the identification of potential co-therapeutic targets that may work synergistically with or after CD14 inhibition to improve microelectrode performance.

Tetrahedral framework nucleic acids promote diabetic wound healing via the Wnt signalling pathway

Objectives

To determine the therapeutic effect of tetrahedral framework nucleic acids (tFNAs) on diabetic wound healing and the underlying mechanism.

Materials and Methods

The tFNAs were characterized by polyacrylamide gel electrophoresis (PAGE), atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential assays. Cell Counting Kit‐8 (CCK‐8) and migration assays were performed to evaluate the effects of tFNAs on cellular proliferation and migration. Quantitative polymerase chain reaction (Q‐PCR) and enzyme‐linked immunosorbent assay (ELISA) were used to detect the effect of tFNAs on growth factors. The function and role of tFNAs in diabetic wound healing were investigated using diabetic wound models, histological analyses and western blotting.

Results

Cellular proliferation and migration were enhanced after treatment with tFNAs in a high‐glucose environment. The expression of growth factors was also facilitated by tFNAs in vitro. During in vivo experiments, tFNAs accelerated the healing process in diabetic wounds and promoted the regeneration of the epidermis, capillaries and collagen. Moreover, tFNAs increased the secretion of growth factors and activated the Wnt pathway in diabetic wounds.

Conclusions

This study indicates that tFNAs can accelerate diabetic wound healing and have potential for the treatment of diabetic wounds.

Twenty Years Development of Tibial Cortex Transverse Transport Surgery in PR China

Tibial cortex transverse transport (TTT) surgery is an extension of the Ilizarov technique. Based on the law of tension‐stress, its primary function is to rebuild microcirculation which can relieve ischemic symptoms and promote wound healing. It has received more and more scholars' attention and has experienced a series of changes for 20 years since it entered PR China. The mechanisms involved have gradually become clear, such as the reconstruction of the polarization balance of macrophages, the promotion of vascular tissue regeneration, and the mobilization and regulation of bone marrow‐derived stem cells. TTT technique is mainly used in the treatment of chronic ischemic diseases of the lower extremities. It has recently been successfully used in the treatment of primary lymphedema of the lower extremities. A series of improvements have been made in the external fixator's style, the size of skin incision and osteotomy, and distraction method. For example, the annular external fixator has been redesigned as a unilateral external fixator, and accordion technology has been introduced. For distraction methods after surgery, there was no uniform standard in the past. The technique can also be used in combination with other treatments to achieve better effects, such as interventional therapy, negative pressure sealed drainage, 3D printing technology, traditional Chinese medicine. Nevertheless, the surgery may bring some complications, such as secondary fracture, nail infection, skin necrosis at the surgical site, etc. Reports of complications and doubts about the technique have made the TTT technique controversial. In 2020, the relevant expert consensus was published with treatment and management principles, which might guide the better application and development of this technique.

Promotive effects of four herbal medicine ARCC on wound healing in mice and human

Background

Traditional Chinese medicine (TCM) had been extensively used in China for wound management and had shown great potential in wound treatment while its mechanism is still needed to be addressed.

Objective

The present study sought to investigate the therapuetic effect of the TCM ARCC on acute and chronic wounds.

Methods

Here, using the ultra‐low temperature preparation method, the mixed ultramicro powder prepared with Angelica (A), Angelica (R), Calcined Gypsum (C) and Caleramide (C) named as ARCC. The effects of ARCC on wound healing in adult and aged mice were comparatively evaluated through a full‐thickness skin defect model. In addition, we randomly selected 10 patients aged 55 to 70 years from a cohort of 500 patients with diabetic feet to assess their prognosis.

Results

As the results showed that the healing rate had delayed in aged mice compared to adult mice, while ARCC prominently augmented the healing process in aged mice. Moreover, ARCC treatment wounds in aged mice showed accelerated re‐epithelization, enhanced granulation tissue formation, and increased vascularization, which was similar to that of adult mice. Furthermore, ARCC also achieved therapeutic effects in diabetic foot patients, accelerating wound healing. The results found that foot ulcers improved significantly 7 days after the ARCC administration, and 80% of patients were healed within 1 month.

Discussion

In the present study, ARCC was found to have therapeutic effects on both acute and chronic wounds in animal models. ARCC also demonstrated therapeutic effects in diabetic feet, which promoted wound healing, prevented wound infection, and avoided the risk of further surgery or amputation. All these evidences suggested ARCC was a promising approach for wound treatment.

Conclusions

ARCC might be recommended as a promising therapeutic medication in diabetic and chronic refractory wounds.

Managing Wound Healing with a High-Risk Patient: A Case Report

Wound healing is a complex, multi-step process. This process begins immediately after skin damage. The outcome of wound healing depends on the quality of each stage of this process: a normal or pathological scar. Violation of wound healing entails a decrease in the function of scar tissue as well as aesthetic dissatisfaction with the patient. This problem is especially important in aesthetic surgery. Patients who have come for beauty feel frustration, obtaining pathological scars. We have been dealing with the problem of wound healing after plastic surgery for about 10 years. Our approach includes the assessment of the risk of pathological wound healing and the treatment of high-risk patients. The risk assessment includes historical data on wound healing, signs of connective tissue dysfunction (especially patients with connective tissue dysplasia), and genetic polymorphisms of genes responsible for the structure of the components of the extracellular matrix of the skin. In the future, patients with a high risk of pathological scarring can be prescribed treatment after surgery. This article presents a clinical case in which we demonstrate our approach.

Bletilla striata polysaccharide modified collagen fiber composite sponge with rapid hemostasis function

Emergencies often result in uncontrollable bleeding, which is thought to be the leading cause of death at the scene of the injured. Among various hemostasis scenarios, collagen fiber (CF) is gradually replacing traditional hemostatic materials due to its superior properties and ease of sourcing from animals. Herein, we use CF and the natural herbaceous Bletilla striata as raw materials to prepare a collagen fiber-oxidized Bletilla striata composite hemostatic sponge (CFOB). During the cross-linking process, the triple helix structure of collagen stays intact, and its porous three-dimensional network structure brings excellent bulkiness and water absorption properties. Experiments show that the optimal amount of sponge CFOB-10, namely oxidized Bletilla striata polysaccharide 0.5 mg/mL and CF 5 mg/mL, only needed 25 ± 4.06 s for hemostasis time in the rat liver hemorrhage model. In addition, CFOB meets the safety performance requirements of cytotoxicity classification standard 0. Therefore, the optimal amount of CFOB is an excellent new hemostatic material with application potential.

Graphical Abstract

A novel hydrogel based on Bletilla striata polysaccharide for rapid hemostasis: Synthesis, characterization and evaluation

The purpose of this study is to develop a new polysaccharide-based hydrogel. The Box-Behnken design was used to optimize the optimal synthesis conditions of the hydrogel, with the swelling parameters as indicators. The findings of rheologic tests confirm that free radical polymerization and the introduction of linear polymers improved the mechanical strength of the hydrogel. Combined with the characterization results, the gel mechanism of BSP-g-PAA/PVA DN hydrogel was proposed. The intermolecular association and entanglement increase, which effectively dissipates energy, thereby enhancing the mechanical properties of the hydrogel. In vitro blood compatibility experiments show that DN hydrogel has a low hemolysis rate and a good coagulation effect. The material is non-cytotoxic to L929 cells. The hepatic haemorrhage and mouse-tail amputation models of rats and mice were used to further evaluate the in vivo wound sealing and hemostatic properties of the hydrogel. The blood loss and hemostatic time were significantly lower than those of the control group, indicating that the hydrogel has excellent hemostatic effects. Therefore, the obtained BSP-g-PAA/PVA DN network hydrogel has good comprehensive properties and is expected to be used as a hemostatic material or a precursor of a drug carrier and a tissue engineering scaffold.

Dermal Fibroblast Migration and Proliferation Upon Wounding or Lipopolysaccharide Exposure is Mediated by Stathmin

The dermal fibroblast is a crucial executor involved in wound healing, and lipopolysaccharide is a key factor in initiating the migration and proliferation of the dermal fibroblasts, followed by wound healing. However, the underlying molecular mechanism is still unknown. In this study, we demonstrated that stathmin increased concomitantly with p38/MAPK pathway activation by lipopolysaccharide stimulation of the human dermal fibroblast (HDF), which induced microtubule (MT) depolymerization followed by increased HDF migration and proliferation. In contrast, the application of taxol, the small interfering RNA transfection of stathmin, or the application of the p38/MAPK inhibitor SB203580 suppressed MT depolymerization and HDF migration and proliferation. Additionally, the overexpression of a MKK6(Glu) mutant, which constitutively activated p38/MAPK, resulted in MT depolymerization and, subsequently, promoted HDF migration and proliferation. Our data reveal a crucial role of stathmin in HDF migration and proliferation. These findings will provide new targets and strategies for clinical interventions in wound healing.

Application of Electrospun Nanofiber Membrane in the Treatment of Diabetic Wounds

Diabetic wounds are complications of diabetes which are caused by skin dystrophy because of local ischemia and hypoxia. Diabetes causes wounds in a pathological state of inflammation, resulting in delayed wound healing. The structure of electrospun nanofibers is similar to that of the extracellular matrix (ECM), which is conducive to the attachment, growth, and migration of fibroblasts, thus favoring the formation of new skin tissue at the wound. The composition and size of electrospun nanofiber membranes can be easily adjusted, and the controlled release of loaded drugs can be realized by regulating the fiber structure. The porous structure of the fiber membrane is beneficial to gas exchange and exudate absorption at the wound, and the fiber surface can be easily modified to give it function. Electrospun fibers can be used as wound dressing and have great application potential in the treatment of diabetic wounds. In this study, the applications of polymer electrospun fibers, nanoparticle-loaded electrospun fibers, drug-loaded electrospun fibers, and cell-loaded electrospun fibers, in the treatment of diabetic wounds were reviewed, and provide new ideas for the effective treatment of diabetic wounds.

Amphibian-derived peptide homodimer promotes regeneration of skin wounds

Despite the increasing treatments in skin wound repair, existing therapeutic drugs cannot meet current needs. As such, skin wound repair remains a considerable clinical challenge, and thus the discovery of new pro-healing agents is crucial. Here, we identified the first naturally occurring peptide homodimer named as OA-GP11 dimer (OA-GP11d) from Odorrana andersonii (odorous frog) through the combinational methods of peptidomics and genomics. OA-GP11d was linked by the intramolecular disulfide formed by the 10^th cysteine residues from the monomer of peptide with sequence of GPLSGINAECM, which effectively promoted the repair of full-thickness and burn wounds in mice. The underlying molecular mechanisms revealed that OA-GP11d not only accelerated the migration and cell-scratch healing of mouse keratinocytes, but also activated the mitogen-activated protein kinases (MAPKs) signaling pathway (phosphorylation of p38 and ERK subgroups) in immortalized human keratinocytes (HaCaT). Besides, OA-GP11d reduced the phosphorylation of nuclear factor-κB (NF-κB) and inhibitor of NF-κB (I-κB) induced by lipopolysaccharide stimulation in mouse macrophages, and inhibited the release of associated inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-6. OA-GP11d is the first identified naturally occurring peptide dimer with significant pro-healing potency. Our results highlight the importance of amphibians as a source of novel pro-healing agents and suggest OA-GP11d as a potential new pro-regenerative drug candidate.

The Role of Extracellular Matrix in Skin Wound Healing

Impaired wound healing is one of the unsolved problems of modern medicine, affecting patients’ quality of life and causing serious economic losses. Impaired wound healing can manifest itself in the form of chronic skin wounds or hypertrophic scars. Research on the biology and physiology of skin wound healing disorders is actively continuing, but, unfortunately, a single understanding has not been developed. The attention of clinicians to the biological and physiological aspects of wound healing in the skin is necessary for the search for new and effective methods of prevention and treatment of its consequences. In addition, it is important to update knowledge about genetic and non-genetic factors predisposing to impaired wound healing in order to identify risk levels and develop personalized strategies for managing such patients. Wound healing is a very complex process involving several overlapping stages and involving many factors. This thematic review focuses on the extracellular matrix of the skin, in particular its role in wound healing. The authors analyzed the results of fundamental research in recent years, finding promising potential for their transition into real clinical practice.

Biomolecules in cell-derived extracellular vesicle chariots as warriors to repair damaged tissues

In this review, we highlight the innovative applications of biomolecules from parent cell-derived extracellular vesicles (EVs) for tissue repair that have been developed in recent years. We evaluate the underlying mechanisms and therapeutic efficacy of each therapy. In previous literature reviews, it was most common to classify the use of EVs in tissue repair by disease type. This article reviews the role of three biomolecules in EVs in tissue repair. This review first summarizes the definitions and classifications of EVs. Then, the importance and significance of treating tissue damage with EVs are discussed. In particular, EV contents for tissue repair are three main types of biomolecules: proteins, RNAs and cell growth factors. The therapeutic and repair mechanisms of the biomolecules are discussed respectively. Finally, the development prospect and potential challenges of EV contents from highly differentiated cells as specific agents for tissue repair are summarized. When EVs are used to treat diseases such as tissue or organ damage, EVs play a role in delivery, and the real repair effect is effected by the various biomolecules carried by EVs. We believe that EV biomolecules have unparalleled advantages and clinical transformation potential for tissue repair and expect this review to inspire more intensive research work in this field.

Dealing with MDR bacteria and biofilm in the post-antibiotic era: Application of antimicrobial peptides-based nano-formulation

The rapid development of multidrug-resistant (MDR) bacteria due to the improper and overuse of antibiotics and the ineffective performance of antibiotics against the difficult-to-treat biofilm-related infections (BRIs) have urgently called for alternative antimicrobial agents and strategies in combating bacterial infections. Antimicrobial peptides (AMPs), owing to their compelling antimicrobial activity against MDR bacteria and BRIs without causing bacteria resistance, have attracted extensive attention in the research field. With the development of nanomaterial-based drug delivery strategies, AMPs-based nano-formulations have significantly improved the therapeutic effects of AMPs by ameliorating their hydrolytic stability, half-life in vivo, and solubility as well as reducing the cytotoxicity and hemolysis, etc. This review has comprehensively summarized the application AMPs-based nano-formulation in various bacterial infections models, including bloodstream infections (specifically sepsis), pulmonary infections, chronic wound infections, gastrointestinal infections, among others. The design of the nanomaterial-based drug delivery systems and the therapeutic effects of the AMPs-based nano-formulations in literature have been categorized and in details discussed. Overall, this review provides insights into the advantages and disadvantages of the current developed AMPs-based nano-formulations in literature for the treatment of bacterial infections, bringing inspirations and suggestions for their future design in the way towards clinical translation.

Evaluation of the cutaneous wound healing potential of tamanu oil in wounds induced in rats

AIMS

Tamanu is a plant oil derived from the fruit and seeds of the Calophyllum inophyllum tree. Although scientific data on tamanu oil are limited, it is recommended worldwide for the treatment of abrasions, burns, diabetic wounds and scars. This study aimed to compare the wound healing efficacy of the topical use of tamanu oil with a reference drug in rats.

METHODS

Uniform wounds were induced on the dorsum of 21 rats, randomly divided into three groups. The control group received normal saline; the tamanu group received tamanu oil; and the centella group was treated with Centella asiatica. Wound healing was clinically evaluated using wound healing scoring and wound contraction. A biopsy was taken from the wound sites of each rat on days 7, 14 and 21 for histopathological evaluation.

RESULTS

Wound contraction was significantly lower in the tamanu group compared with the other groups. On day 7, the intensity of macrophage infiltration and mature granulation tissues were significantly higher in the centella and tamanu groups than in the control group. Fibrosis and collagen density were higher in the tamanu group than the other groups on day 7.

CONCLUSION

In wound healing in rats, tamanu oil accelerated the formation of macrophage-granulation tissues-fibrosis and resulted in less wound contraction.

Multifunctional Zinc Oxide/Silver Bimetallic Nanomaterial-Loaded Nanofibers for Enhanced Tissue Regeneration and Wound Healing

Native skin repair requires wound care products that not only protect the wound from bacterial infection, but also accelerate wound closure and minimize scarring. Nanomaterials have been widely applied for wound healing due to their multifunctional properties. In a previous study, we prepared and characterized electrospinning zinc oxide/silver/polyvinylpyrrolidone/polycaprolactone (ZnO/Ag/PVP/PCL) nanofibers using ZnO and Ag nanoparticles, and evaluated their antibacterial effect in vitro. In this work, further characterization studies were performed, which confirmed that the ZnO/Ag nanoparticles were physically embedded and evenly distributed in the ZnO/Ag/PVP/PCL nanofibers, enabling the sustained release of Ag and Zn. In addition, the bimetallic nanofibers showed satisfactory fluid handling and flexibility. In vivo wound healing and histology studies showed that the ZnO/Ag/PVP/PCL nanofibers had a better anti-inflammatory, skin tissue regeneration, and wound healing effect than monometallic nanofibers or a commercially available wound plaster (Yunnan Baiyao). Therefore, ZnO/Ag/PVP/PCL bimetallic nanofibers may be a safe, efficient biomedical dressing for wound healing.

Nanocarrier-Mediated Topical Insulin Delivery for Wound Healing

Wound care has been clinically demanding due to inefficacious treatment that represents an economic burden for healthcare systems. In Europe, approximately 7 million people are diagnosed with untreated wounds, leading to a cost between 6.000€ and 10.000€ per patient/year. In the United States of America, 1.5 million people over 65 years old suffer from chronic wounds. A promising therapeutic strategy is the use of exogenous growth factors because they are decreased at the wound site, limiting the recovery of the skin. Insulin is one of the cheapest growth factors in the market able to accelerate the re-epithelialization and stimulate angiogenesis and cell migration. However, the effectiveness of topical insulin in wound healing is hampered by the proteases in the wound bed. The encapsulation into nanoparticles improves its stability in the wound, providing adhesion to the mucosal surface and allowing its sustained release. The aim of this review is to perform a standing point about a promising strategy to treat different types of wounds by the topical delivery of insulin-loaded nanocarriers.

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

INTRODUCTION

Wound injury is common and causes serious complications if not treated properly. The moist dressing heals wounds faster than other dressings. Therefore, we sought to study the effect of hesperidin/naringin hydrogel wound dressing or their combinations on the deep dermal wounds in mice.

METHODS

A rectangular full thickness skin flap of 2.5 × 1.5 cm was excised from depilated mice dorsum and the wound was fully covered with 5% hesperidin/5% naringin hydrogel or both in the ratio of 1:1, 2:1, or 1:2, respectively once daily until complete healing of the wound. Data were collected on wound contraction, mean wound healing time, collagen, DNA, and nitric oxide syntheses, glutathione concentration, superoxide dismutase activity, and lipid peroxidation throughout healing. Expression of NF-κB and COX-2 were also estimated in the regenerating granulation tissue using Western blot.

FINDINGS

Dressing of wounds with 5% hesperidin hydrogel led to a higher and early wound contraction and significantly reduced mean wound healing time by 5.7 days than 5% naringin or combination of hesperidin and naringin hydrogels in the ratio of 1:1, 2:1, or 1:2. Hesperidin hydrogel wound dressing caused higher collagen and DNA syntheses than other groups at all times after injury. Glutathione concentration and superoxide dismutase activity increased followed by a decline in lipid peroxidation in regenerating wounds after hesperidin/naringin hydrogel application and a maximum effect was observed for hesperidin alone. The hesperidin/naringin hydrogel suppressed NF-κB and COX-2 expression on days 6 and 12.

CONCLUSIONS

Application of 5% hesperidin hydrogel was more effective than 5% naringin or combination of hesperidin and naringin gels (1:1, 2:1 or 1:2) indicated by a greater wound contraction, reduced mean wound healing time, elevated collagen and DNA syntheses, rise in glutathione concentration, and superoxide dismutase activity followed by reduced lipid peroxidation, and NF-κB, and COX-2 expression.

Cytokine concentrations direct endothelial function in pregnancy and preeclampsia

Endothelial dysfunction is a prominent feature of preeclampsia, a hypertensive disorder of pregnancy, and contributes to multiple symptoms characteristic of the syndrome. A myriad of growth factors and cytokines are dysregulated in preeclampsia as compared to normal pregnancy, however, a complete appreciation of the effect of changing concentrations of these factors on endothelial function is lacking. In this study, we evaluate the effect of a variety of growth factors and cytokines on Ca2+ signaling and monolayer integrity. We report that VEGF165, TNFα, EGF, and IL-1β either improve or inhibit Ca2+ signaling depending on dose, whereas TNFα and IL-1β reduce monolayer integrity and bFGF increases monolayer integrity. Additionally, to model the effects of combinations of growth factors and cytokines, we screened for Ca2+ signaling changes in response to 16 dose combinations of VEGF165 and TNFα together. This revealed an optimal combination capable of supporting pregnancy-adapted Ca2+ signaling, and that changes in either VEGF165 or TNFα dose would result in a shift toward suppressed function. This study shows in detail how growth factor or cytokine concentration effects endothelial cell function. Such data can be used to model how changing growth factor and cytokine levels in normal pregnancy may contribute to healthy endothelial function and in preeclampsia may promote endothelial dysfunction. The results of VEGF165 and TNFα combination treatments suggest that more complex growth factor and cytokine combination modeling may be important in order to more accurately understand the effects of circulating factors on the endothelial function.

Aloe vera: A Medicinal Plant Used in Skin Wound Healing

Skin injury is a major problem threatening human physical and mental health, and how to promote wound healing has been the focus. Developing new wound dressings is an important strategy in skin regeneration. Aloe vera is a medicinal plant with a long history, complex constituents, and various pharmacological activities. Many studies have shown that A. vera plays an important role in promoting wound healing. Adding A. vera to wound dressing has become an ideal way. This review will describe the process of skin injury and wound healing and analyze the role of A. vera in wound healing. In addition, the types of wound dressing and the applications of A. vera in wound dressing will be discussed.

An Overview of Biopolymeric Electrospun Nanofibers Based on Polysaccharides for Wound Healing Management

Currently, despite the thoroughgoing scientific research carried out in the area of wound healing management, the treatment of skin injuries, regardless of etiology remains a big provocation for health care professionals. An optimal wound dressing should be nontoxic, non-adherent, non-allergenic, should also maintain a humid medium at the wound interfacing, and be easily removed without trauma. For the development of functional and bioactive dressings, they must meet different conditions such as: The ability to remove excess exudates, to allow gaseous interchange, to behave as a barrier to microbes and to external physical or chemical aggressions, and at the same time to have the capacity of promoting the process of healing by stimulating other intricate processes such as differentiation, cell adhesion, and proliferation. Over the past several years, various types of wound dressings including hydrogels, hydrocolloids, films, foams, sponges, and micro/nanofibers have been formulated, and among them, the electrospun nanofibrous mats received an increased interest from researchers due to the numerous advantages and their intrinsic properties. The drug-embedded nanofibers are the potential candidates for wound dressing application by virtue of: Superior surface area-to volume ratio, enormous porosity (can allow oxy-permeability) or reticular nano-porosity (can inhibit the microorganisms'adhesion), structural similitude to the skin extracellular matrix, and progressive electrospinning methodology, which promotes a prolonged drug release. The reason that we chose to review the formulation of electrospun nanofibers based on polysaccharides as dressings useful in wound healing was based on the ever-growing research in this field, research that highlighted many advantages of the nanofibrillary network, but also a marked versatility in terms of numerous active substances that can be incorporated for rapid and infection-free tissue regeneration. In this review, we have extensively discussed the recent advancements performed on electrospun nanofibers (eNFs) formulation methodology as wound dressings, and we focused as well on the entrapment of different active biomolecules that have been incorporated on polysaccharides-based nanofibers, highlighting those bioagents capable of improving the healing process. In addition, in vivo tests performed to support their increased efficacy were also listed, and the advantages of the polysaccharide nanofiber-based wound dressings compared to the traditional ones were emphasized.

[Research progress of tibial transverse transport in treatment of chronic ischemic diseases of the lower extremities]

OBJECTIVE

To summarize the research progress of tibial transverse transport (TTT) in treatment of chronic ischemic diseases of the lower extremities.

METHODS

The related literature was systematically searched and the mechanisms, clinical treatment methods, clinical efficacy, indications, contraindications, and complications of TTT were discussed.

RESULTS

Based on the law of tension-stress, TTT is a new method in the treatment of chronic ischemic diseases of the lower extremities. It can relieve the ischemic symptoms, promote the wound healing, and increase the limb salvage rate. The clinical application in recent years has shown good effectiveness, and the scope of application is expanding.

CONCLUSION

Due to the current limited clinical application, the sample size of the TTT for the chronic ischemic diseases of the lower extremities is relatively small, and the follow-up time is limited. So its validity, long-term effectiveness, and bone transport standards are need further research.

Evaluation of stability and in vitro wound healing potential of melatonin loaded (lipid enriched) chitosan based microspheres

The aim of this study was to evaluate long-term stability and assess the wound healing potential of the innovative melatonin-loaded lipid-enriched hybrid system compared to conventional melatonin-loaded chitosan microspheres. The hybrid system contained nanostructured lipid carrier incorporated in the chitosan matrix, in order to modify melatonin release and alter physicochemical characteristics of the delivery system. Stability testing was performed during a six-month period under two conditions: refrigerated (5 ± 3 °C) and at room temperature (25 ± 2 °C/60 ± 5 % RH). Samples stored at both conditions were analyzed in terms of particle size, zeta potential, moisture content and thermal properties. At the end of testing, drug content was determined in all samples. Dressings wound healing potential was assessed by in vitro scratch test using human skin fibroblast cell line. Although both systems showed good stability characteristics, the addition of lipids in the system has improved its wound healing potential.

Nanocarrier-based systems for wound healing

In general, the systems intended for the treatment and recovery of wounds, seek to act as a coating for the damaged area, maintaining an adequate level of humidity, reducing pain, and preventing the invasion and proliferation of microorganisms. Although many of the systems that are currently on the market meet the purposes mentioned above, with the arrival of nanotechnology, it has sought to improve the performance of these coatings. The variety of nano-systems that have been proposed is very extensive, including the use of very different materials (natural or synthetic) ranging from polymers or lipids to systems derived from microorganisms. With the objective of improving the performance of the systems, seeking to combat several of the problems that arise in a wound, especially when it is chronic, these materials have been combined, giving rise to nanocomposites or scaffolds. In recent years, the interest in the development of systems for the treatment of wounds is notable, which is reflected in the increase in publications related to the subject. Therefore, this document presents generalities of systems involving nanocarriers, mentioning some examples of representative systems of each case.

Re-epithelialization of adult skin wounds: Cellular mechanisms and therapeutic strategies

Cutaneous wound healing in adult mammals is a complex multi-step process involving overlapping stages of blood clot formation, inflammation, re-epithelialization, granulation tissue formation, neovascularization, and remodelling. Re-epithelialization describes the resurfacing of a wound with new epithelium. The cellular and molecular processes involved in the initiation, maintenance, and completion of epithelialization are essential for successful wound closure. A variety of modulators are involved, including growth factors, cytokines, matrix metalloproteinases, cellular receptors, and extracellular matrix components. Here, we focus on cellular mechanisms underlying keratinocyte migration and proliferation during epidermal closure. Inability to re-epithelialize is a clear indicator of chronic non-healing wounds, which fail to proceed through the normal phases of wound healing in an orderly and timely manner. This review summarizes the current knowledge regarding the management and treatment of acute and chronic wounds, with a focus on re-epithelialization, offering some insights into novel future therapies.

Predictive Approach Identifies Molecular Targets and Interventions to Restore Angiogenesis in Wounds With Delayed Healing

Impaired angiogenesis is a hallmark of wounds with delayed healing, and currently used therapies to restore angiogenesis have limited efficacy. Here, we employ a computational simulation-based approach to identify influential molecular and cellular processes, as well as protein targets, whose modulation may stimulate angiogenesis in wounds. We developed a mathematical model that captures the time courses for platelets, 9 cell types, 29 proteins, and oxygen, which are involved in inflammation, proliferation, and angiogenesis during wound healing. We validated our model using previously published experimental data. By performing global sensitivity analysis on thousands of simulated wound-healing scenarios, we identified six processes (among the 133 modeled in total) whose modulation may improve angiogenesis in wounds. By simulating knockouts of 25 modeled proteins and by simulating different wound-oxygenation levels, we identified four proteins [namely, transforming growth factor (TGF)-β, vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), and angiopoietin-2 (ANG-2)], as well as oxygen, as therapeutic targets for stimulating angiogenesis in wounds. Our modeling results indicated that simultaneous inhibition of TGF-β and supplementation of either FGF-2 or ANG-2 could be more effective in stimulating wound angiogenesis than the modulation of either protein alone. Our findings suggest experimentally testable intervention strategies to restore angiogenesis in wounds with delayed healing.