Highly efficient local delivery of endothelial progenitor cells significantly potentiates angiogenesis and full-thickness wound healing

Granular Porous Nanofibrous Microspheres Enhance Cellular Infiltration for Diabetic Wound Healing

Diabetic foot ulcers (DFUs) are a significant challenge in the clinical care of diabetic patients, often necessitating limb amputation and compromising the quality of life and life expectancy of this cohort. Minimally invasive therapies, such as modular scaffolds, are at the forefront of current DFU treatment, offering an efficient approach for administering therapeutics that accelerate tissue repair and regeneration. In this study, we report a facile method for fabricating granular nanofibrous microspheres (NMs) with predesigned structures and porosities. The proposed technology combines electrospinning and electrospraying to develop a therapeutic option for DFUs. Specifically, porous NMs were constructed using electrospun poly(lactic-co-glycolic acid) (PLGA):gelatin short nanofibers, followed by gelatin cross-linking. These NMs demonstrated enhanced cell adhesion to human dermal fibroblasts (HDF) during an in vitro cytocompatibility assessment. Notably, porous NMs displayed superior performance owing to their interconnected pores compared to nonporous NMs. Cell-laden NMs demonstrated higher Young's modulus values than NMs without loaded cells, suggesting improved material resiliency attributed to the reinforcement of cells and their secreted extracellular matrix. Dynamic injection studies on cell-laden NMs further elucidated their capacity to safeguard loaded cells under pressure. In addition, porous NMs promoted host cell infiltration, neovascularization, and re-epithelialization in a diabetic mouse wound model, signifying their effectiveness in healing diabetic wounds. Taken together, porous NMs hold significant potential as minimally invasive, injectable treatments that effectively promote tissue integration and regeneration.

Collaborative Enhancement of Diabetic Wound Healing and Skin Regeneration by Recombinant Human Collagen Hydrogel and hADSCs

Stem cell-based therapies hold significant promise for chronic wound healing and skin appendages regeneration, but challenges such as limited stem cell lifespan and poor biocompatibility of delivery systems hinder clinical application. In this study, an in situ delivery system for human adipose-derived stem cells is developed (hADSCs) to enhance diabetic wound healing. The system utilizes a photo-crosslinking recombinant human type III collagen (rHCIII) hydrogel to encapsulate hADSCs, termed the hADSCs@rHCIII hydrogel. This hydrogel undergoes local crosslinking at the wound site, establishing a sturdy 3D niche suitable for stem cell function. Consequently, the encapsulated hADSCs exhibit strong attachment and spreading within the hydrogels, maintaining their proliferation, metabolic activity, and viability for up to three weeks in vitro. Importantly, in vivo studies demonstrate that the hADSCs@rHCIII hydrogel achieves significant in situ delivery of stem cells, prolonging their retention within the wound. This ultimately enhances their immunomodulatory capabilities, promotes neovascularization and granulation tissue formation, facilitates matrix remodeling, and accelerates healing in a diabetic mouse wound model. Collectively, these findings highlight the potential of the conveniently-prepared and user-friendly hADSCs@rHCIII hydrogel as a promising therapeutic approach for diabetic wound treatment and in situ skin regeneration.

Laponite/lactoferrin hydrogel loaded with eugenol for methicillin-resistant Staphylococcus aureus-infected chronic skin wound healing

Severe bacterial infections can give rise to protracted wound healing processes, thereby posing a significant risk to a patient's well-being. Consequently, the development of a versatile hydrogel dressing possessing robust bioactivity becomes imperative, as it holds the potential to expedite wound healing and yield enhanced clinical therapeutic outcomes. In this context, the present study involves the formulation of an injectable multifunctional hydrogel utilizing laponite (LAP) and lactoferrin (LF) as foundational components and loaded with eugenol (EG). This hydrogel is fabricated employing a straightforward one-pot mixing approach that leverages the principle of electrostatic interaction. The resulting LAP/LF/EG2% composite hydrogel can be conveniently injected to address irregular wound geometries effectively. Once administered, the hydrogel continually releases lactoferrin and eugenol, mitigating unwarranted oxidative stress and eradicating bacterial infections. This orchestrated action culminates in the acceleration of wound healing specifically in the context of MRSA-infected wounds. Importantly, the LAP/LF/EG2% hydrogel exhibits commendable qualities including exceptional injectability, potent antioxidant attributes, and proficient hemostatic functionality. Furthermore, the hydrogel composition notably encourages cellular migration while maintaining favorable cytocompatibility. Additionally, the hydrogel manifests noteworthy bactericidal efficacy against the formidable multidrug-resistant MRSA bacterium. Most significantly, this hydrogel formulation distinctly expedites the healing of MRSA-infected wounds by promptly inducing hemostasis, curbing bacterial proliferation, and fostering angiogenesis, collagen deposition, and re-epithelialization processes. As such, the innovative hydrogel material introduced in this investigation emerges as a promising dressing for the facilitation of bacterial-infected wound healing and consequent tissue regeneration.

Relieving Macrophage Dysfunction by Inhibiting SREBP2 Activity: A Hypoxic Mesenchymal Stem Cells-Derived Exosomes Loaded Multifunctional Hydrogel for Accelerated Diabetic Wound Healing

Macrophage dysfunction is one of the primary factors leading to the delayed healing of diabetic wounds. Hypoxic bone marrow mesenchymal stem cells-derived exosomes (hyBMSC-Exos) have been shown to play an active role in regulating cellular function through the carried microRNAs. However, the administration of hyBMSC-Exos alone in diabetic wounds usually brings little effect, because the exosomes are inherently unstable and have a short retention time at the wounds. In this study, a multifunctional hydrogel based on gallic acid (GA) conjugated chitosan (Chi-GA) and partially oxidized hyaluronic acid (OHA) is prepared for sustained release of hyBMSC-Exos. The hydrogel not only exhibits needs-satisfying physicochemical properties, but also displays outstanding biological performances such as low hemolysis rate, strong antibacterial capacity, great antioxidant ability, and excellent biocompatibility. It has the ability to boost the stability of hyBMSC-Exos, leading to a continuous and gradual release of the exosomes at wound locations, ultimately enhancing the exosomes' uptake efficiency by target cells. Most importantly, hyBMSC-Exos loaded hydrogel shows an excellent ability to promote diabetic wound healing by regulating macrophage polarization toward M2 phenotype. This may be because exosomal miR-4645-5p and antioxidant property of the hydrogel synergistically inhibit SREBP2 activity in macrophages. This study presents a productive approach for managing diabetic wounds.

Hyaluronic acid hydrogels with excellent self-healing capacity and photo-enhanced mechanical properties for wound healing

A continuously stable moist healing environment is immensely beneficial for wound healing, which can be availably achieved by providing an in situ hydrogel with enough strength resembling skin tissue and self-healing ability. Herein, through a dual-crosslinking strategy, hyaluronic acid-based hydrogels with excellent self-healing capacity and enhanced mechanical properties are fabricated via the acylhydrazone linkages and subsequent photocrosslinking based on hydrazide-modified sodium hyaluronate and aldehyde-modified maleic sodium hyaluronate. The hydrogels demonstrate the fast gelation process (< 1 min), the controlled swelling behaviors, and the good biocompatibility. Notably, they possess enhanced mechanical strength similar to the human dermis (∼ 2.2 kPa). Also, they can self-heal rapidly with a self-healing efficiency of ∼90 % at 6 h. Based on this, the hyaluronic acid-based hydrogels, without any biological factors involved, can facilitate the full-thickness skin wound reconstruction process by accelerating the three phases of the wound repair, including reducing wound inflammation in the inflammatory phase, promoting angiogenesis in the proliferative phase, and promoting the deposition and reconstruction of collagen in the remodeling phase. The produced hyaluronic acid hydrogel can serve as an ideal candidate for wound healing.

Bioactive-Glass-Based Materials with Possible Application in Diabetic Wound Healing: A Systematic Review

Diabetes affected 537 million adults in 2021, costing a total of USD 966 billion dollars in healthcare. One of the most common complications associated with diabetes corresponds to the development of diabetic foot ulcers (DFUs). DFUs affect around 15% of diabetic patients; these ulcers have impaired healing due to neuropathy, arterial disease, infection, and aberrant extracellular matrix (ECM) degradation, among other factors. The bioactive-glass-based materials discussed in this systematic review show promising results in accelerating diabetic wound healing. It can be concluded that the addition of BG is extremely valuable with regard to the wound healing rate and wound healing quality, since BG activates fibroblasts, enhances M1-to-M2 phenotype switching, induces angiogenesis, and initiates the formation of granulation tissue and re-epithelization of the wound. In addition, a higher density and deposition and better organization of collagen type III are seen. This systematic review was made using the PRISMA guideline and intends to contribute to the advancement of diabetic wound healing therapeutic strategies development by providing an overview of the materials currently being developed and their effect in diabetic wound healing in vitro and in vivo.

Anti-Inflammatory Effect of Fermented Cabbage Extract Containing Nitric Oxide Metabolites with Silica

The aim of this study was to evaluate the anti-inflammatory effect of fermented cabbage extract (FC) containing nitric oxide metabolites with silica (FCS) on 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced atopic dermatitis (AD) in BALB/c mice. Atopic dermatitis-like allergic contact dermatitis was induced by DNFB challenge in the ear after DNFB sensitization on the dorsal skin of mice. FCS alleviated the severity of atopic dermatitis-like skin lesions. In addition, epidermis thickness of the ear and penetration of inflammatory cells in atopic dermatitis-like skin lesions were decreased after topical application of FCS. The serum levels of TNF-α and IL-4 were measured in atopic dermatitis mice using ELISA kits, which were observed to be significantly decreased after topical application of FCS. This study demonstrates that the FCS can be used as a potential therapeutic for the treatment and prevention of AD.

A Multifunctional Hydrogel for Simultaneous Visible H2 O2 Monitoring And Accelerating Diabetic Wound Healing

Diabetic wound is one of the chronic wounds that is difficult to heal, and effective treatment of it still confronts a great challenge. Monitoring the variation of diabetic wound microenvironment (such as hydrogen peroxide (H2 O2 )) can understand the wound state and guide the wound management. Herein, a multifunctional hydrogel with the abilities of monitoring the H2 O2 concentration, alleviating oxidative stress and promoting wound healing is developed, which is prepared by encapsulating manganese-containing bioactive glass (MnBG) and CePO4 :Tb in biocompatible gelatin methacryloyl (GelMA) hydrogel (CPT-MnBG-Gel). On the one hand, the H2 O2 -dependent fluorescence quenching effect of the CePO4 :Tb contributes to visible monitoring of the H2 O2 concentration of wounds via smartphone imaging, and the CPT-MnBG-Gel hydrogel can effectively monitor the H2 O2 level of 10.35-200 µmol L-1 . On the other hand, MnBG can alleviate oxidative stress and promote the proliferation, migration and differentiation of fibroblasts and endothelial cells in vitro owing to the bioactive Mn and Si ions, and in vivo evaluation also demonstrates that the CPT-MnBG-Gel hydrogels can effectively accelerate wound healing. Hence, such multifunctional hydrogel is promising for diabetic wound management and accelerating wound healing.

Sonic hedgehog signaling promotes angiogenesis of endothelial progenitor cells to improve pressure ulcers healing by PI3K/AKT/eNOS signaling

BACKGROUND

Pressure ulcer is a severe disease in the paralyzed and aging populations. Endothelial progenitor cells (EPCs) are able to regulate ulcer healing by modulating angiogenesis, but the molecular mechanism is still obscure. Sonic hedgehog (SHH) signaling contributes to angiogenesis in various diseases and has been identified to modulate EPCs function. Here, we aimed to explore the significance of SHH signaling in EPCs function during pressure ulcers.

METHODS

The EPCs were isolated and characterized by the expression of DiI-acLDL and bind fluorescein iso-thiocyanate UEA-1. Cell proliferation was detected by cell counting kit 8 (CCK-8). The DiI-acLDL and bind fluorescein iso-thiocyanate UEA-1 were analyzed by immunofluorescent analysis. The angiogenesis of EPCs was analyzed by tube formation assay. The pressure ulcers rat model was constructed, the wound injury was analyzed by H&E staining and angiogenesis was analyzed by the accumulation of CD31 based on immunofluorescent analysis.

RESULTS

The expression of patched-1 and Gli-1 was enhanced by SHH activator SAG but reduced by SHH inhibitor cyclopamine in the EPCsThe PI3K, Akt, eNOS expression and the Akt phosphorylation were induced by SAG, while the treatment of cyclopamine presented a reversed result. The proliferation and migration of EPCs were enhanced by SAG but repressed by cyclopamine or PI3K/AKT/eNOS signaling inhibitor Y294002, in which the co-treatment of Y294002 could reverse the effect of SAG.

CONCLUSIONS

Thus, we found that SHH signaling activated angiogenesis properties of EPCs to improve pressure ulcers healing by PI3K/AKT/eNOS signaling. SHH signaling may serve as the potential target for attenuating pressure ulcers.

Prussian blue nano-enzyme-assisted photodynamic therapy effectively eradicates MRSA infection in diabetic mouse skin wounds

Antibiotic therapy can induce the generation of severe bacterial resistance, further challenging the usability of currently available drugs and treatment options. Therefore, it is essential to develop new strategies to effectively eradicate drug-resistant bacteria. Herein, we have reported a combinational strategy for the eradication of drug-resistant bacteria by using chlorin e6 (Ce6) loaded Prussian blue nanoparticles (PB NPs). This nanocomplex showed strong catalase activity and photodynamic properties. In vitro experiments demonstrated that CPB-Ce6 NPs effectively kill MRSA by generating ROS under laser irradiation. Meanwhile, the nano-enzyme activity of CPB NPs can decompose H2O2 in the bacterial microenvironment to upregulate the O2 level, which in turn alleviates hypoxia in the microenvironment and improves the antibacterial effect of PDT. In vivo results demonstrated that CPB-Ce6 NPs with laser irradiation effectively cleared MRSA and promoted infected wound repair in a diabetic mouse model and normal mice through upregulating VEGF. Moreover, CPB-Ce6 NPs showed excellent biosafety profiles in vitro and in vivo. From our point of view, this PDT based on PB NPs with nano-enzyme activity may provide an effective treatment for infections associated with drug-resistant microbes and tissue repair.

3D-Printed Functional Hydrogel by DNA-Induced Biomineralization for Accelerated Diabetic Wound Healing

Chronic wounds in diabetic patients are challenging because their prolonged inflammation makes healing difficult, thus burdening patients, society, and health care systems. Customized dressing materials are needed to effectively treat such wounds that vary in shape and depth. The continuous development of 3D-printing technology along with artificial intelligence has increased the precision, versatility, and compatibility of various materials, thus providing the considerable potential to meet the abovementioned needs. Herein, functional 3D-printing inks comprising DNA from salmon sperm and DNA-induced biosilica inspired by marine sponges, are developed for the machine learning-based 3D-printing of wound dressings. The DNA and biomineralized silica are incorporated into hydrogel inks in a fast, facile manner. The 3D-printed wound dressing thus generates provided appropriate porosity, characterized by effective exudate and blood absorption at wound sites, and mechanical tunability indicated by good shape fidelity and printability during optimized 3D printing. Moreover, the DNA and biomineralized silica act as nanotherapeutics, enhancing the biological activity of the dressings in terms of reactive oxygen species scavenging, angiogenesis, and anti-inflammation activity, thereby accelerating acute and diabetic wound healing. These bioinspired 3D-printed hydrogels produce using a DNA-induced biomineralization strategy are an excellent functional platform for clinical applications in acute and chronic wound repair.

Photocatalytic Ag/AgBr-MBG for Rapid Antibacterial and Wound Repair

In daily life and during surgery, the skin, as the outermost organ of the human body, is easily damaged to form wounds. If the wound was infected by the bacteria, especially the drug-resistant bacteria such as methicillin-resistant staphylococcus aureus (MRSA), it was difficult to recover. Therefore, it was important to develop the safe antimicrobial strategy to inhibit bacterial growth in the wound site, in particular, to overcome the problem of bacterial drug resistance. Here, the Ag/AgBr-loaded mesoporous bioactive glass (Ag/AgBr-MBG) was prepared, which had excellent photocatalytic properties under simulated daylight for rapid antibacterial activity within 15 min by generating reactive oxygen species (ROS). Meanwhile, the killing rate of Ag/AgBr-MBG against MRSA was 99.19% within 15 min, which further reduced the generation of drug-resistant bacteria. In addition, Ag/AgBr-MBG particles could disrupt bacterial cell membranes, showing the broad-spectrum antibacterial properties and promoting tissue regeneration and infected wound healing. Ag/AgBr-MBG particles might have potential applications as a light-driven antimicrobial agent in the field of biomaterials.

Engineered multi-functional, pro-angiogenic collagen-based scaffolds loaded with endothelial cells promote large deep burn wound healing

The lack of vascularization associated with deep burns delays the construction of wound beds, increases the risks of infection, and leads to the formation of hypertrophic scars or disfigurement. To address this challenge, we have fabricated a multi-functional pro-angiogenic molecule by grafting integrin αvβ3 ligand LXW7 and collagen-binding peptide (SILY) to a dermatan sulfate (DS) glycosaminoglycan backbone, named LXW7-DS-SILY (LDS), and further employed this to functionalize collagen-based Integra scaffolds. Using a large deep burn wound model in C57/BLK6 mice (8-10 weeks old, 26-32g, n = 39), we demonstrated that LDS-modified collagen-based Integra scaffolds loaded with endothelial cells (ECs) accelerate wound healing rate, re-epithelialization, vascularization, and collagen deposition. Specifically, a 2 cm × 3 cm full-thickness skin burn wound was created 48 h after the burn, and then wounds were treated with four groups of different dressing scaffolds, including Integra + ECs, Integra + LDS, and Integra + LDS + ECs with Integra-only as the control. Digital photos were taken for wound healing measurement on post-treatment days 1, 7, 14, 21, 28, and 35. Post-treatment photos revealed that treatment with the Intgera + LDS + ECs scaffold exhibited a higher wound healing rate in the proliferation phase. Histology results showed significantly increased re-epithelialization, increased collagen deposition, increased thin and mixed collagen fiber content, increased angiogenesis, and shorter wound length within the Integra + LDS + ECs group at Day 35. On Day 14, the Integra + LDS + ECs group showed the same trend. The relative proportions of collagen changed from Day 14 to Day 35 in the Integra + LDS + ECs and Integra + ECs groups demonstrated decreased thick collagen fiber deposition and greater thin and mixed collagen fiber deposition. LDS-modified Integra scaffolds represent a promising novel treatment to accelerate deep burn wound healing, thereby potentially reducing the morbidity associated with open burn wounds. These scaffolds can also potentially reduce the need for autografting and morbidity in patients with already limited areas of harvestable skin.

Current and future outlook of loaded components in hydrogel composites for the treatment of chronic diabetic ulcers

Due to recalcitrant microangiopathy and chronic infection, traditional treatments do not easily produce satisfactory results for chronic diabetic ulcers. In recent years, due to the advantages of high biocompatibility and modifiability, an increasing number of hydrogel materials have been applied to the treatment of chronic wounds in diabetic patients. Research on composite hydrogels has received increasing attention since loading different components can greatly increase the ability of composite hydrogels to treat chronic diabetic wounds. This review summarizes and details a variety of newly loaded components currently used in hydrogel composites for the treatment of chronic diabetic ulcers, such as polymer/polysaccharides/organic chemicals, stem cells/exosomes/progenitor cells, chelating agents/metal ions, plant extracts, proteins (cytokines/peptides/enzymes) and nucleoside products, and medicines/drugs, to help researchers understand the characteristics of these components in the treatment of diabetic chronic wounds. This review also discusses a number of components that have not yet been applied but have the potential to be loaded into hydrogels, all of which play roles in the biomedical field and may become important loading components in the future. This review provides a "loading component shelf" for researchers of composite hydrogels and a theoretical basis for the future construction of "all-in-one" hydrogels.

Chitosan and carboxymethyl cellulose-based 3D multifunctional bioactive hydrogels loaded with nano-curcumin for synergistic diabetic wound repair

Biopolymer-based thermoresponsive injectable hydrogels with multifunctional tunable characteristics containing anti-oxidative, biocompatibility, anti-infection, tissue regeneration, and/or anti-bacterial are of abundant interest to proficiently stimulate diabetic wound regeneration and are considered as a potential candidate for diversified biomedical application but the development of such hydrogels remains a challenge. In this study, the Chitosan-CMC-g-PF127 injectable hydrogels are developed using solvent casting. The Curcumin (Cur) Chitosan-CMC-g-PF127 injectable hydrogels possess viscoelastic behavior, good swelling properties, and a controlled release profile. The degree of substitution (% DS), thermal stability, morphological behavior, and crystalline characteristics of the developed injectable hydrogels is confirmed using nuclear magnetic resonance (¹H NMR), thermogravimetric analysis, scanning electron microscopy (SEM), and x-ray diffraction analysis (XRD), respectively. The controlled release of cur-micelles from the hydrogel is evaluated by drug release studies and pharmacokinetic profile (PK) using high-performance liquid chromatography (HPLC). Furthermore, compared to cur micelles the Cur-laden injectable hydrogel shows a significant increase in half-life (t_1/2) up to 5.92 ± 0.7 h, mean residence time (MRT) was 15.75 ± 0.76 h, and area under the first moment curve (AUMC) is 3195.62 ± 547.99 μg/mL*(h)² which reveals the controlled release behavior. Cytocompatibility analysis of Chitosan-CMC-g-PF127 hydrogels using 3T3-L1 fibroblasts cells and in vivo toxicity by subcutaneous injection followed by histological examination confirmed good biocompatibility of Cur-micelles loaded hydrogels. The histological results revealed the promising tissue regenerative ability and shows enhancement of fibroblasts, keratinocytes, and collagen deposition, which stimulates the epidermal junction. Interestingly, the Chitosan-CMC-g-PF127 injectable hydrogels ladened Cur exhibited a swift wound repair potential by up-surging the cell migration and proliferation at the site of injury and providing a sustained drug delivery platform for hydrophobic moieties.

Natural Carrier-Free Binary Small Molecule Self-Assembled Hydrogel Synergize Antibacterial Effects and Promote Wound Healing by Inhibiting Virulence Factors and Alleviating the Inflammatory Response

Methicillin-resistant Staphylococcus aureus (MRSA)-infected skin wounds have caused a variety of diseases and seriously endanger global public health. Therefore, multidimensional strategies are urgently to find antibacterial dressings to combat bacterial infections. Antibacterial hydrogels are considered potential wound dressing, while their clinical translation is limited due to the unpredictable risks and high costs of carrier excipients. it is found that the natural star antibacterial and anti-inflammatory phytochemicals baicalin (BA) and sanguinarine (SAN) can directly self-assemble through non-covalent bonds such as electrostatic attraction, π-π stacking, and hydrogen bonding to form carrier-free binary small molecule hydrogel. In addition, BA-SAN gel exhibited a synergistic inhibitory effect on MRSA. And its plasticity and injectability allowed it to be applied as a wound dressing. Due to the matched physicochemical properties and synergistic therapeutic effects, BA-SAN gel can inhibit bacterial virulence factors, alleviate wound inflammation, promote wound healing, and has good biocompatibility. The current study not only provided an antibacterial hydrogel with clinical value but also opened up new prospects that carrier-free hydrogels can be designed and originated from clinically used small-molecule phytochemicals.

Bioinspired multifunctional injectable hydrogel for hemostasis and infected wound management

Routine wound management faces significant challenges including rebleeding and bacterial infection that affect millions of people each year. However, conventional wound dressings (e.g., gauze, bandage) are limited to simply cover the injured surfaces and rarely show special functionality to promote the wound recovery. Currently, injectable hydrogels have been widely designed as multifunctional wound dressings to manage the hemostatic and wound healing process. Nevertheless, the integration of multiple functions through simple composition and easy construction is still difficult and hardly achieved. Herein, we reported a bioinspired multifunctional injectable hydrogel (CQCS@gel) consisted of only two components, catechol-functionalized quaternized chitosan (CQCS) and dibenzaldehyde-terminated poly(ethylene glycol) (DB-PEG₂₀₀₀). The building blocks endowed CQCS@gel with tissue-adhesive, antibacterial, antioxidant, self-healing and pH-responsive properties. Based on the in vivo hemostatic study, quick hemostasis for acute tissue injuries such as liver and carotid wounds was realized owing to the rapid gelation rate and strong tissue-adhesiveness of CQCS@gel. Moreover, CQCS@gel remarkably boosted the chronic recovery process of MRSA-infected cutaneous wounds by promoting collagen deposition, hair follicles regeneration and angiogenesis. Overall, this multifunctional injectable hydrogel shows potentials as a universal wound dressing in clinical applications, enabling both hemostasis and infected wound management. STATEMENT OF SIGNIFICANCE: This is the first report showing the multifunctional injectable hydrogel (CQCS@gel) consisted of catechol-functionalized quaternized chitosan and dibenzaldehyde-terminated poly(ethylene glycol). The incorporation of quaternary ammonium groups imparted the CQCS@gel with outstanding contact-active bacterial killing efficiency and the catechol moieties enhanced its tissue adhesive and antioxidant properties. Moreover, the reversible imine crosslinks endowed the CQCS@gel with self-healing and pH-responsive drug release capabilities. These multiple functions were integrated into a single injectable hydrogel system with easy availability and low cost. In vitro and in vivo results showed that the newly designed hydrogel was biocompatible, realized successful sealing hemostasis under multiple bleeding scenarios and enabled accelerated healing of infected skin wounds.

Anti-inflammatory effect of simvastatin by impeding TNF-α and interleukin-1ß pathways: antiangiogenic activity of simvastatin and simvastatin-loaded silver nanoparticles

PURPOSE

The present study was carried out to evaluate anti-inflammatory and antiangiogenic attributes of simvastatin and its nanofilms containing silver nanoparticles.

METHODS

Silver nanoparticles and simvastatin-loaded nanocomposite (SNSN) films were formulated by using polymeric solution (pectin + sericin) through casting solution method. Different in vitro and in vivo anti-inflammatory assays were performed. In addition, chick chorioallantoic membrane assay (CAM) was also employed for angiogenesis activity.

RESULTS

FTIR spectra of the film depicted the presence of intact simvastatin. Differential scanning calorimetry exhibited no endothermic expression in F9 film thermogram. The simvastatin release from all films exhibited a burst effect. Cotton-pellet induced granuloma model study showed that high dose of simvastatin and indomethacin produced comparable (p < 0.05) anti-inflammatory effect. Noteworthy, RT-PCR showed dose-dependent, anti-oedematous effect of simvastatin through downregulation of serum TNF-α and interleukin-1ß levels. While results of CAM assay exhibited remarkable anti-angiogenic potential of SNSN films showing dissolved blood vessels network macroscopically.

CONCLUSION

To reiterate, simvastatin and its SNSN films can add significant contribution to the field of biomedicines due to their promising anti-inflammatory and antiangiogenic properties, however, clinical studies are required to validate their commercial use.

Clickable and smart drug delivery vehicles accelerate the healing of infected diabetic wounds

In this study, an adipic acid dihydrazide (ADH)/ tannic acid (TA)-grafted hyaluronic acid (HA)-based multifunctional hydrogel was synthesized through a spontaneous amino-yne click reaction and used to promote the improved healing of infected diabetic wounds. This hydrogel exhibited a range of beneficial properties such as tunable gelation time, adjustable mechanical properties, pH-sensitive response characteristics, excellent injectability, the ability to readily adhere to tissue, and ultra-intimate contact capabilities. Following the encapsulation of ultrasmall Ag nanoclusters (AgNCs) and deferoxamine loaded polydopamine/ hollow mesoporous manganese dioxide (PHMD, PDA/H-mMnO₂@DFO) nanoparticles, the prepared hydrogel presented with robust antibacterial, anti-inflammatory, and pro-angiogenic properties and a desirable smart drug release profile. In this fabricated platform, PHMD was able to effectively alleviate localized oxidative stress and prolonged oxygen deprivation via the decomposition of endogenous H₂O₂ to produce O₂. Further in vivo assays revealed that this hydrogel was capable of facilitating the healing of infected wounds through the sequential engagement of antibacterial, anti-inflammatory, and pro-angiogenic activities. Together, this synthesized clickable environmentally-responsive hydrogel offers great promise as a tool that can be applied to aid in the healing of chronically infected diabetic wounds and other inflammatory conditions.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

A poloxamer/hyaluronic acid/chitosan-based thermosensitive hydrogel that releases dihydromyricetin to promote wound healing

Wounds caused by accidents and surgery are inevitable, and inflammation and microbial infection during the healing process are serious clinical challenges, resulting in slow wound healing. In this study, we created a 37 °C-sensitive hydrogel using poloxamer, chitosan and hyaluronic acid, loaded with the active substance dihydromyricetin, and further evaluated its potential for wound healing. The hydrogels were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis for their micromorphological structure, characteristic functional groups, crystal structure and thermal stability, and in vitro drug release assays showed that the hydrogel could slowly release dihydromyricetin. In addition, the hydrogels were found to exhibit good biocompatibility and significant in vitro antioxidant and anti-inflammatory activity according to hemolysis, in vitro antioxidant and anti-inflammatory tests. Methyl thiazolyl tetrazole cytotoxicity tests verified that the film was non-toxic to human keratinocyte (HaCaT) cells, while in vivo experiments showed that this hydrogel could promote skin repair by promoting skin-associated growth factor expression and inhibiting nuclear factor kappa B-mediated cellular inflammatory factors. These results demonstrated that the temperature-sensitive hydrogels loaded with dihydromyricetin could serve as potential candidates for guided skin repair.

Biopolymeric composite hydrogel loaded with silver NPs and epigallocatechin gallate (EGCG) effectively manages ROS for rapid wound healing in type II diabetic wounds

Delayed wound healing in patients having type-II diabetes mellitus (T2DM) often results in a high rate of amputation. We report an innovative Guar Gum-based macroporous hydrogel (HG) infused with an antibacterial agent (Ag NPs), and antioxidant, epigallocatechin gallate (EGCG) to address rapid wound healing and interestingly could inhibit the associated pathophysical bone infection in a high-fat-diet-induced T2DM C57BL/6 mice model. The HG-Ag-EGCG elicits scar-free wound healing in subcutaneous wounds and histopathological evidence confirmed HG-Ag-EGCG hydrogel patch elicits better wound healing through enhanced cell proliferation, mature connecting tissue fiber formation, minimum void spaces formation, and better re-epithelialization when compared with a market available hydrogel patch material (Luofucon®). Supportive of the in vivo outcomes, in vitro experiments delineated better-wound closure due to improved management of ROS by the HG-Ag-EGCG. Additionally, a favorable non-toxicity outcome assessed through both in vitro and in vivo conditions confirmed its potential applicability in clinical wound care management.

Immunoregulation in Diabetic Wound Repair with a Photoenhanced Glycyrrhizic Acid Hydrogel Scaffold

M1 macrophage accumulation and excessive inflammation are commonly encountered issues in diabetic wounds and can fail in the healing process. Hence, hydrogel dressings with immunoregulatory capacity have great promise in the clinical practice of diabetic wound healing. However, current immunoregulatory hydrogels are always needed for complex interventions and high-cost treatments, such as cytokines and cell therapies. In this study, a novel glycyrrhizic acid (GA)-based hybrid hydrogel dressing with intrinsic immunoregulatory properties is developed to promote rapid diabetic wound healing. This hybrid hydrogel consists of interpenetrating polymer networks composed of inorganic Zn²⁺ -induced self-assembled GA and photo-crosslinked methyl acrylated silk fibroin (SF), realizing both excellent injectability and mechanical strength. Notably, the SF/GA/Zn hybrid hydrogel can regulate macrophage responses in the inflammatory microenvironment, circumventing the use of any additives. The immunomodulatory properties of the hydrogel can be harnessed for safe and efficient therapeutics that accelerate the three phases of wound repair and serve as a promising dressing for the management of diabetic wounds.

A review of current advancements for wound healing: Biomaterial applications and medical devices

Wound healing is a complex process that is critical in restoring the skin's barrier function. This process can be interrupted by numerous diseases resulting in chronic wounds that represent a major medical burden. Such wounds fail to follow the stages of healing and are often complicated by a pro‐inflammatory milieu attributed to increased proteinases, hypoxia, and bacterial accumulation. The comprehensive treatment of chronic wounds is still regarded as a significant unmet medical need due to the complex symptoms caused by the metabolic disorder of the wound microenvironment. As a result, several advanced medical devices, such as wound dressings, wearable wound monitors, negative pressure wound therapy devices, and surgical sutures, have been developed to correct the chronic wound environment and achieve skin tissue regeneration. Most medical devices encompass a wide range of products containing natural (e.g., chitosan, keratin, casein, collagen, hyaluronic acid, alginate, and silk fibroin) and synthetic (e.g., polyvinyl alcohol, polyethylene glycol, poly[lactic‐co‐glycolic acid], polycaprolactone, polylactic acid) polymers, as well as bioactive molecules (e.g., chemical drugs, silver, growth factors, stem cells, and plant compounds). This review addresses these medical devices with a focus on biomaterials and applications, aiming to deliver a critical theoretical reference for further research on chronic wound healing.

pH-Switchable Antimicrobial Supramolecular Hydrogels for Synergistically Eliminating Biofilm and Promoting Wound Healing

Biofilm infection will cause chronic inflammation and hinder the normal healing process of wound. Here, based on the self-assembly of three designed amphiphilic pentapeptides named EK, GG, and DR, pH-switchable antibacterial hydrogels with amphiphilic fiber network are used for the eradication of biofilms and the rescue of delayed healing in infected wounds. These pentapeptides-based hydrogels exhibit an acidic pH-switchable antimicrobial effect and are biocompatible at neutral pH. Additionally, supramolecular nanofiber networks with physical cross-linking with thermosensitive polymers (PNIPAm) and loaded antibacterial oregano oil are further developed. In vitro experiments indicate that the antimicrobial activity of hydrogels comes from the disassembly of acidic pH-dependent nanofiber network and activated release of pentapeptides and oregano oil, which achieves synergistic biofilm eradication. Remarkably, DR-based supramolecular hydrogel improves the healing efficiency of the full-thickness wound of skin in vivo, which is manifested by increased wound closure rate, reduced inflammatory response, faster angiogenesis, and collagen deposition in the wound, exhibiting great potential as wound dressing. The proposed synergistic strategy of inhibiting biofilm formation and activating healing may provide an efficient method for the treatment of clinically infected wounds.

Development of a Microenvironment-Responsive Hydrogel Promoting Chronically Infected Diabetic Wound Healing through Sequential Hemostatic, Antibacterial, and Angiogenic Activities

Microenvironment-responsive hydrogels present high potential in treating refractory wounds due to their capability of on-demand drug release. In this study, a specially designed hydrogel with smart targeting of refractory wound characteristics was designed to treat chronically infected diabetic wounds. Aminated gelatin reacted with oxidized dextran, forming a hydrogel cross-linked with a dynamic Schiff base, which is sensitive to the low-pH environment in refractory wounds. Nano-ZnO was loaded into the hydrogel for killing microbes. A Paeoniflorin-encapsulated micelle with a ROS-responsive property was fixed to the skeleton of the hydrogel via a Schiff base bond for low-pH- and ROS-stimulated angiogenic activity. The sequential responsiveness of the novel hydrogel enabled smart rescue of the deleterious microenvironment in refractory wounds. This highly biocompatible hydrogel demonstrated antibacterial and angiogenic abilities in vitro and significantly promoted healing of chronically infected diabetic wounds via sequential hemostatic, microbe killing, and angiogenic activities. This microenvironment-responsive hydrogel loaded with nZnO and Pf-encapsulated micelles holds great potential as a location-specific dual-response delivery platform for curing refractory, chronically infected diabetic wounds.

Bioactive extracellular matrix scaffolds engineered with proangiogenic proteoglycan mimetics and loaded with endothelial progenitor cells promote neovascularization and diabetic wound healing

Diabetic ischemic wound treatment remains a critical clinical challenge. Neovascularization plays a significant role in wound healing during all stages of the tissue repair process. Strategies that enhance angiogenesis and neovascularization and improve ischemic pathology may promote the healing of poor wounds, particularly diabetic wounds in highly ischemic conditions. We previously identified a cyclic peptide LXW7 that specifically binds to integrin αvβ3 on endothelial progenitor cells (EPCs) and endothelial cells (ECs), activates vascular endothelial growth factor (VEGF) receptors, and promotes EC growth and maturation. In this study, we designed and synthesized a multi-functional pro-angiogenic molecule by grafting LXW7 and collagen-binding peptides (SILY) to a dermatan sulfate (DS) glycosaminoglycan backbone, named LXW7-DS-SILY, and further employed this multi-functional molecule to functionalize collagen-based extracellular matrix (ECM) scaffolds. We confirmed that LXW7-DS-SILY modification significantly promoted EPC attachment and growth on the ECM scaffolds in vitro and supported EPC survival in vivo in the ischemic environment. When applied in an established Zucker Diabetic Fatty (ZDF) rat ischemic skin flap model, LXW7-DS-SILY-functionalized ECM scaffolds loaded with EPCs significantly improved wound healing, enhanced neovascularization and modulated collagen fibrillogenesis in the ischemic environment. Altogether, this study provides a promising novel treatment to accelerate diabetic ischemic wound healing, thereby reducing limb amputation and mortality of diabetic patients.

Biomedical applications of electrospun nanofibers in the management of diabetic wounds

Diabetes mellitus (DM) is a complex disease that affects almost all the body's vital organs. Around 415 million people have been diagnosed with DM worldwide, and most of them are due to type 2 DM. The incidence of DM is estimated to increase by 642 million individuals by 2040. DM is considered to have many complications among which diabetic wound (DW) is one of the most distressing complication. DW affects 15% of people with diabetes and is triggered by the loss of glycaemic control, peripheral neuropathy, vascular diseases, and immunosuppression. For timely treatment, early detection, debridement, offloading, and controlling infection are crucial. Even though several treatments are available, the understanding of overlying diabetes-related wound healing mechanisms as therapeutic options has increased dramatically over the past decades. Conventional dressings are cost-effective; however, they are not productive enough to promote the overall process of DW healing. Thanks to tissue engineering developments, one of the promising current trends in innovative wound dressings such as hydrocolloids, hydrogels, scaffolds, films, and nanofibers which merges traditional healing agents and modern products/practices. Nanofibers prepared by electrospinning with enormous porosity, excellent absorption of moisture, the better exchange rate of oxygen, and antibacterial activities have increased interest. The application of these nanofibers can be extended by starting with a careful selection of polymers, loading with active therapeutic moieties such as peptides, proteins, active pharmaceutical ingredients (API), and stem cells, etc. to make them as potential dosage forms in the management of DWs. This review explains the potential applications of electrospun nanofibers in DW healing. A schematic view of role of nanofibers in diabetic wounds.

Endothelial progenitor cells and coronary artery disease: Current concepts and future research directions

Vascular injury is a frequent pathology in coronary artery disease. To repair the vasculature, scientists have found that endothelial progenitor cells (EPCs) have excellent properties associated with angiogenesis. Over time, research on EPCs has made encouraging progress regardless of pathology or clinical technology. This review focuses on the origins and cell markers of EPCs, and the connection between EPCs and coronary artery disease. In addition, we summarized various studies of EPC-capturing stents and EPC infusion therapy, and aim to learn from past technology to predict the future.

Exosomes from linc00511-overexpressing ADSCs accelerates angiogenesis in diabetic foot ulcers healing by suppressing PAQR3-induced Twist1 degradation

AIMS

We aim to investigate the role of ADSCs (Adipose-derived stem cells)-derived exosomes on regulating angiogenesis in diabetic foot ulcers healing.

METHODS

EPCs (endothelial progenitor cells) from human peripheral blood were applied as in vitro model of angiogenesis. Exosomes isolated from ADSCs culture medium were characterized by electron microscopy, size distribution and biomarker expression. Cell proliferation, migration, apoptosis and angiogenesis were detected by CCK-8 and EdU staining, wound healing, flow cytometry and tube formation assays, respectively. Rat diabetic foot model was further constructed for the evaluation of wound healing and histological alterations.

RESULTS

EPCs from diabetes showed suppressed proliferation, migration and angiogenesis and decreased Twist1 protein. Similarly, high glucose repressed the proliferation, migration and angiogenesis of EPCs, which also elevated PAQR3 and suppressed Twist1 expression. However, these impaired EPCs biological functions were recovered by the application of exosomes from linc00511-overexpressing ADSCs, along with increased Twist1 and decreased PAQR3. Mechanistically, PAQR3 overexpression reduced Twist1 protein level in EPCs by enhancing BTRC-mediated Twist1 ubiquitin degradation. Exosomes from linc00511-overexpressing ADSCs alleviated rat diabetic foot ulcers by inhibiting Twist1 ubiquitination to promote angiogenesis.

CONCLUSION

Exosomes from linc00511-overexpressing ADSCs promotes diabetic foot ulcers healing by accelerating angiogenesis via suppressing PAQR3-induced Twist1 ubiquitin degradation.

Biomimetic Hydrogels to Promote Wound Healing

Wound healing is a common physiological process which consists of a sequence of molecular and cellular events that occur following the onset of a tissue lesion in order to reconstitute barrier between body and external environment. The inherent properties of hydrogels allow the damaged tissue to heal by supporting a hydrated environment which has long been explored in wound management to aid in autolytic debridement. However, chronic non-healing wounds require added therapeutic features that can be achieved by incorporation of biomolecules and supporting cells to promote faster and better healing outcomes. In recent decades, numerous hydrogels have been developed and modified to match the time scale for distinct stages of wound healing. This review will discuss the effects of various types of hydrogels on wound pathophysiology, as well as the ideal characteristics of hydrogels for wound healing, crosslinking mechanism, fabrication techniques and design considerations of hydrogel engineering. Finally, several challenges related to adopting hydrogels to promote wound healing and future perspectives are discussed.

Novel lipophosphonoxin-loaded polycaprolactone electrospun nanofiber dressing reduces Staphylococcus aureus induced wound infection in mice

Active wound dressings are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected skin wound healing. As the wide use of antibiotics leads to drug resistance we present here a new concept of wound dressings based on the polycaprolactone nanofiber scaffold (NANO) releasing second generation lipophosphonoxin (LPPO) as antibacterial agent. Firstly, we demonstrated in vitro that LPPO released from NANO exerted antibacterial activity while not impairing proliferation/differentiation of fibroblasts and keratinocytes. Secondly, using a mouse model we showed that NANO loaded with LPPO significantly reduced the Staphylococcus aureus counts in infected wounds as evaluated 7 days post-surgery. Furthermore, the rate of degradation and subsequent LPPO release in infected wounds was also facilitated by lytic enzymes secreted by inoculated bacteria. Finally, LPPO displayed negligible to no systemic absorption. In conclusion, the composite antibacterial NANO-LPPO-based dressing reduces the bacterial load and promotes skin repair, with the potential to treat wounds in clinical settings.

In vitro and in vivo advancement of multifunctional electrospun nanofiber scaffolds in wound healing applications: Innovative nanofiber designs, stem cell approaches, and future perspectives

The skin is one of the most essential tissues in the human body, interacting with the outside environment and shielding the body from diseases and excessive water loss. Hydrogels, decellularized porcine dermal matrix, and lyophilized polymer scaffolds have all been used in studies of skin wound repair, wound dressing, and skin tissue engineering, however, these materials cannot replicate the nanofibrous architecture of the skin's native extracellular matrix (ECM). Electrospun nanofibers are a fascinating new form of nanomaterials with tremendous potential across a broad spectrum of applications in the biomedical field, including wound dressings, wound healing scaffolds, regenerative medicine, bioengineering of skin tissue, and multifaceted drug delivery. This article reviews recent in vitro and in vivo developments in multifunctional electrospun nanofibers (MENs) for wound healing. This review begins with an introduction to the electrospinning process, its principle, and the processing parameters which have a significant impact on the nanofiber properties. It then discusses the various geometries and advantages of MEN scaffolds produced by different innovative electrospinning techniques for wound healing applications when used in combination with stem cells. This review also discusses some of the possible future nanofiber-based models that could be used. Finally, we conclude with potential perspectives and conclusions in this area.

Inflammation-Responsive Drug-Loaded Hydrogels with Sequential Hemostasis, Antibacterial, and Anti-Inflammatory Behavior for Chronically Infected Diabetic Wound Treatment

Stimuli-responsive hydrogels possess unique advantages in drug delivery due to their variable performance and status based on the external environment. In the present study, a dual-responsive (pH and reactive oxygen species (ROS)) hydrogel was prepared to realize drug release properties under inflammatory stimulation. By grafting 3-carboxy-phenylboronic acid to the gelatin molecular backbone and cross-linking with poly(vinyl alcohol), we successfully synthesized the inflammation-responsive drug-loaded hydrogels after encapsulation with vancomycin-conjugated silver nanoclusters (VAN-AgNCs) and pH-sensitive micelles loaded with nimesulide (NIM). This novel design not only retained the dynamic functions of hydrogels, such as injectability, self-healing, and remodeling, but also realized sequential and on-demand drug delivery at diabetic-infected wound sites. In this work, we found that the hydrogel exhibited excellent biocompatibility and hemostasis properties owing to the enhanced cell-adhesive property of the gelatin component. The significant antibacterial and anti-inflammatory effect of the hydrogel was demonstrated in an in vitro experiment. Moreover, in the in vivo experiment, the hydrogel was found to play a role in promoting infected wound healing through sequential hemostasis and antibacterial and anti-inflammatory processes. Collectively, this inflammation-responsive hydrogel design containing VAN-AgNCs and NIM-loaded micelles has great potential in the application of chronically infected diabetic wound treatment, as well as in other inflammatory diseases.

The cardioprotective effect and mechanism of bioactive glass on myocardial reperfusion injury

Myocardial reperfusion treatment for ischemic infarction may cause lethal injury of cardiomyocytes, which is known as ischemia/reperfusion (I/R) injury. As a kind of prospective biomaterial with superior properties, the application of bioactive glasses (BGs) in myocardial tissue engineering have received great interests. In this study, the cardioprotective effect and relevant mechanism of BG on myocardial reperfusion injury were investigatedin vitro. H9c2 cardiomyocytes were pretreated with BG extracts and then cultured in hypoxic environment for 30 min followed by reoxygenation for 1 h. The activity of released lactate dehydrogenase (LDH) and the content of malondialdehyde (MDA) in H9c2 cells were tested by assay kits. Cell viability was analyzed by Live/Dead staining assay and the number of living cells was detected by Cell Counting Kit-8 (CCK-8) assay. The cytoskeletal protein F-actin was stained and observed under inverted fluorescence microscope. Mitochondrial membrane potential (MMP) level, reactive oxygen species (ROS) production and apoptosis ratio were evaluated by fluorescent observation and flow cytometry simultaneously. The gene expressions relevant to apoptosis were detected by quantitative real time polymerase chain reaction (qRT-PCR) analysis. The results showed that BG extracts effectively inhibited hypoxia/reoxygenation (H/R)-induced cell injury by suppressing oxidative stress and mitochondrial permeability transition (MPT) within H9c2 cells. Meanwhile, apoptosis caused by H/R injury was alleviated and three classic apoptotic signaling pathways were proved to be regulated by BG extracts. Further analysis showed that phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway was up-regulated in H/R-induced H9c2 cells by BG extracts, leading to relieved cellular apoptosis. These results indicated that BG might exert cardioprotective effect in reperfusion injury when applied in myocardial tissue regeneration and repair.

Anti-inflammation biomaterial platforms for chronic wound healing

Nowadays, there has been an increase in the number of people with chronic wounds, which has resulted in serious health problems worldwide. The rate-limiting stage of chronic wound healing has been found to be the inflammation stage, and strategies for shortening the prolonged inflammatory response have proven to be effective for increasing the healing rate. Recently, various anti-inflammatory strategies (such as anti-inflammatory drugs, antioxidant, NO regulation, antibacterial, immune regulation and angiogenesis) have attracted attention as potential therapeutic pathways. Moreover, various biomaterial platforms based on anti-inflammation therapy strategies have also emerged in the spotlight as potential therapies to accelerate the repair of chronic wounds. In this review, we systematically investigated the advances of various biomaterial platforms based on anti-inflammation strategies for chronic wound healing, to provide valuable guidance for future breakthroughs in chronic wound treatment.

Dilated microvessel with endothelial cell proliferation involves intraplaque hemorrhage in unstable carotid plaque

BACKGROUND

The purpose of the present study was to clarify the characteristics of endothelial cell (EC) proliferation in intraplaque microvessels in vulnerable plaques and impact on clinical results.

METHODS

The present study included 76 patients who underwent carotid endarterectomy. Patients were classified into three groups based on their symptoms: asymptomatic, symptomatic without recurrent ischemic event, and symptomatic with recurrent ischemic event. MR plaque imaging was performed and surgical specimens underwent immunohistochemical analysis. The number of CD31⁺ microvessels, and Ki67⁺ and CD105⁺ ECs in the carotid plaques was quantified, as measurements of maximum CD31⁺ microvessel diameter.

RESULTS

MR plaque imaging yielded 41 subjects (54.0%) diagnosed with plaque with intraplaque hemorrhage (IPH), 14 subjects (18.4%) diagnosed with fibrous plaques, and 21 (27.6%) subjects diagnosed with lipid-rich plaques. The average largest diameter of microvessel in fibrous plaques, lipid-rich plaques, and plaque with IPH was 12.7 ± 4.1 μm, 31.3 ± 9.3 μm, and 56.4 ± 10.0 μm, respectively (p < 0.01). Dilated microvessels (>40 μm) were observed in 9.6% of plaques with IPH but only in 2.8% of lipid-rich plaques and 0% of fibrous plaques (p < 0.01). Ki67⁺/CD31⁺ ECs were identified in 2.8 ± 1.2% of fibrous plaques, 9.6 ± 6.9% of lipid-rich plaques, and in 19.5 ± 5.9% of plaques with IPH (p < 0.01). The average largest diameter of microvessels in the asymptomatic group was 17.1 ± 8.7 μm, 32.3 ± 10.8 μm in the symptomatic without recurrence group, and 55.2 ± 13.2 μm in the symptomatic with recurrence group (p < 0.01).

CONCLUSION

Dilated microvessels with proliferative ECs may play a key role in IPH pathogenesis. Furthermore, dilated microvessels are likely related to clinical onset and the recurrence of ischemic events. The purpose of the present study was to clarify the characteristics of EC proliferation in intraplaque microvessels in vulnerable plaques and their impact on clinical results, focusing on dilated intraplaque microvessels.

Carbon Arc Lamp Therapy Enhances the Repair Potential of Chronic Soft Tissue Injury in Rats Compared with the Ability of Photobiomodulation Therapy

Objective: The effects of photobiomodulation therapy (PBMT) and carbon arc lamp therapy (CALT) on the repair of chronic soft tissue injury were compared. Background data: PBMT improves soft tissue repair of chronic injury. However, there has been no research on the effect of CALT. Methods: Human umbilical vein endothelial cells (HUVECs) were irradiated using PBMT and CALT at 2 J/cm² to observe their effects on cell proliferation and migration. The effects of PBMT and CALT on soft tissue injury repair were assessed using a chronic gastrocnemius injury model of the posterior limb in rats. The malondialdehyde (MDA), superoxide dismutase (SOD), and prostaglandin E2 (PGE2) were examined by biochemical analyses. The degree of tissue damage repair was evaluated by the immunohistochemical method [CD45, CD34, vascular endothelial growth factor (VEGF), and actin] and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. Results: Treatment by PBMT and CALT significantly accelerated the proliferation and migration of HUVECs. Moreover, significant decreases in the contents of MDA and PGE2 were observed in the PBMT and CALT groups, while SOD activity was increased. The histological assessment shows that the content of inflammatory cells and apoptotic cells significantly decreased in the CALT group. However, the microvascular density, VEGF content, and actin content were increased in the CALT group. Conclusions: The results demonstrate that CALT has a stronger effect on promoting chronic soft tissue injury repair in comparison with PBMT.

Injectable Desferrioxamine-Laden Silk Nanofiber Hydrogels for Accelerating Diabetic Wound Healing

Dysangiogenesis and chronic inflammation are two critical reasons for diabetic foot ulcers. Desferrioxamine (DFO) was used clinically in the treatment of diabetic foot ulcers by repeated injections because of its capacity to induce vascularization. Biocompatible carriers that release DFO slowly and facilitate healing simultaneously are preferable options to accelerate the healing of diabetic wounds. Here, DFO-laden silk nanofiber hydrogels that provided a sustained release of DFO for more than 40 days were used to treat diabetic wounds. The DFO-laden hydrogels stimulated the healing of diabetic wounds. In vitro cell studies revealed that the DFO-laden hydrogels modulated the migration and gene expression of endothelial cells, and they also tuned the inflammation behavior of macrophages. These results were confirmed in an in vivo diabetic wound model. The DFO-laden hydrogels alleviated dysangiogenesis and chronic inflammation in the diabetic wounds, resulting in a more rapid wound healing and increased collagen deposition. Both in vitro and in vivo studies suggested potential clinical applications of these DFO-laden hydrogels in the treatment of diabetic ulcers.

Porous bioactive glass micro- and nanospheres with controlled morphology: developments, properties and emerging biomedical applications

In recent years, porous bioactive glass micro/nanospheres (PBGSs) have emerged as attractive biomaterials in various biomedical applications where such engineered particles provide suitable functions, from tissue engineering to drug delivery. The design and synthesis of PBGSs with controllable particle size and pore structure are critical for such applications. PBGSs have been successfully synthesized using melt-quenching and sol-gel based methods. The morphology of PBGSs is controllable by tuning the processing parameters and precursor characteristics during the synthesis. In this comprehensive review on PBGSs, we first overview the synthesis approaches for PBGSs, including both melt-quenching and sol-gel based strategies. Sol-gel processing is the primary technology used to produce PBGSs, allowing for control over the chemical compositions and pore structure of particles. Particularly, the influence of pore-forming templates on the morphology of PBGSs is highlighted. Recent progress in the sol-gel synthesis of PBGSs with sophisticated pore structures (e.g., hollow mesoporous, dendritic fibrous mesoporous) is also covered. The challenges regarding the control of particle morphology, including the influence of metal ion precursors and pore expansion, are discussed in detail. We also highlight the recent achievements of PBGSs in a number of biomedical applications, including bone tissue regeneration, wound healing, therapeutic agent delivery, bioimaging, and cancer therapy. Finally, we conclude with our perspectives on the directions of future research based on identified challenges and potential new developments and applications of PBGSs.

Synthetic Polymeric Antibacterial Hydrogel for Methicillin-Resistant Staphylococcus aureus-Infected Wound Healing: Nanoantimicrobial Self-Assembly, Drug- and Cytokine-Free Strategy

Antibacterial hydrogels are attracting extensive attention in soft tissue repair and regeneration, including bacteria-infected-wound healing. The abuse of antibiotics leads to drug resistance. Recent developments have demonstrated that the delivery of inorganic bactericidal agents in hydrogels can drive the wound healing process; however, this approach is complicated by external light stimuli, cytotoxicity, nondegradability, and sophisticated fabrication. Herein, an inherent antibacterial, bioresorbable hydrogel was developed by the spontaneous self-aggregation of amphiphilic, oxadiazole-group-decorated quaternary ammonium salts (QAS)-conjugated poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC-QAS) micellar nanoantimicrobials for methicillin-resistant Staphylococcus aureus (MRSA)-infected cutaneous wound healing. The PCEC-QAS hydrogel showed a stable gel state within the temperature range of 5-50 °C and antibacterial efficacy against both Gram-negative and -positive bacteria in vitro and in vivo. Additionally, the PCEC-QAS hydrogel facilitated the cell spreading, proliferation, and migration without cytotoxicity. An in vivo degradation and skin defect healing study suggested the PCEC-QAS hydrogel was totally absorbed without local or systemic toxicity and could promote wound repair in the absence of drugs, cytokines, or cells. Significantly, this hydrogel accelerated the regeneration of a MRSA-infected full-thickness impaired skin wound by successfully reconstructing an intact and thick epidermis similar to normal mouse skin. Collectively, a self-assembling PCEC-QAS antibacterial hydrogel is a promising dressing material to promote skin regeneration and prevent bacterial infection without additional drugs, cells, light irradiation, or delivery systems, providing a simple but effective strategy for treating dermal wounds.

Skin wound healing assisted by angiogenic targeted tissue engineering: A comprehensive review of bioengineered approaches

Skin injuries and in particular, chronic wounds, are one of the major prevalent medical problems, worldwide. Due to the pivotal role of angiogenesis in tissue regeneration, impaired angiogenesis can cause several complications during the wound healing process and skin regeneration. Therefore, induction or promotion of angiogenesis can be considered as a promising approach to accelerate wound healing. This article presents a comprehensive overview of current and emerging angiogenesis induction methods applied in several studies for skin regeneration, which are classified into the cell, growth factor, scaffold, and biological/chemical compound-based strategies. In addition, the advantages and disadvantages of these angiogenic strategies along with related research examples are discussed in order to demonstrate their potential in the treatment of wounds.

A bioglass sustained-release scaffold with ECM-like structure for enhanced diabetic wound healing

Aim: To develop an effective strategy for increasing angiogenesis at diabetic wound sites and thereby accelerating wound healing. Materials & methods: A micropatterned nanofibrous scaffold with bioglass nanoparticles encapsulated inside coaxial fibers was prepared by electrospinning. Results: Si ions could be released in a sustained manner from the scaffolds. The hierarchical micro-/nano-structure of the scaffold was found to act as a temporary extracellular matrix to promote endothelial cell adhesion and growth. The scaffold greatly improved angiogenesis and collagen deposition at the wound site, which shortened the healing period of diabetic wounds. Conclusion: This study provides a promising therapeutic option for chronic diabetic wounds with improved angiogenesis.

Electrospun nanofiber-based drug delivery platform: advances in diabetic foot ulcer management

INTRODUCTION

Electrospinning is a facile and viable method for the fabrication of nanofibers. Electrospun nanofiber has a great potential in providing local drug or therapeutic molecule delivery to the wound site. The versatile nature of this technique ensures a broad scope of material used in the fabrication of nanofibers.

AREA COVERED

A brief introduction to diabetic foot ulcer (DFU) is covered with its pathogenesis, followed by the role of electrospun nanofibers in DFU. This review covers the evolution of the electrospinning technique over the past few years, various types of electrospun nanofibers reported for DFU or chronic diabetic wounds, the challenges associated with the preparation of nanofibers, and various methods to evaluate their efficacy and performance in diabetic wound healing.

EXPERT OPINION

Electrospinning-based nanofibers provide a safe, effective, and multifunctional system for effective management of DFU.

Shear stress improves the endothelial progenitor cell function via the CXCR7/ERK pathway axis in the coronary artery disease cases

BACKGROUND

Dysfunction in the late Endothelial Progenitor Cells (EPCs) is responsible for endothelial repair in patients with Coronary Artery Disease (CAD), and the shear stress is beneficial for EPCs function. However, the impact of shear stress on the capacity of EPCs in CAD patients has not been elucidated yet. The C-X-C chemokine receptor 7/extracellular signal-regulated kinase (CXCR7)/(ERK) pathways are identified to regulate EPCs function in CAD patients. Here, we hypothesize that shear stress upregulates the CXCR7/ERK pathways, which restore the EPCs function in CAD patients.

METHODS

The human Peripheral Blood Mononuclear Cells (PBMCs) were collected from healthy adults and CAD patients and then used for EPCs cultivation. The Lv-siRNA for human CXCR7 was transfected into induced EPCs isolated from the CAD patients. Meanwhile, the EPCs from CAD patients were subjected to shear stress generated by a biomimetic device. Next, the cell viability, migration, tube formation, and apoptosis were detected by CCK-8, Transwell assay, Matrigel, and flow cytometry, respectively. Also, the CXCR7/ERK pathways in human EPCs were analyzed by Western blotting and qRT-PCR.

RESULT

Compared to the EPCs collected from normal adults, the CAD patient-derived EPCs showed reduced in vitro vasculogenic capacity. Also, the level of CXCR7 in CAD patient-derived EPCs was significantly reduced compared to the EPCs of healthy subjects. Meanwhile, the extracellular signal-regulated kinase (ERK), which represents a CXCR7 downstream signaling pathway, had decreased phosphorylation level. The shear stress treatment augmented the CXCR7 expression and also elevated ERK phosphorylation, which is comparable to the up-regulation of CAD patient-derived EPCs function. Further, the small interfering RNA (siRNA)-mediated CXCR7 knockdown diminished the enhanced migration, adhesion, and tube formation capacity of shear stress treated CAD patient-derived EPCs.

CONCLUSION

Up-regulation of the CXCR7/ERK pathways by shear stress can be a promising new target in enhancing the vasculogenic ability of CAD patient-derived EPCs.

Extracellular matrix-derived biomaterials in engineering cell function

Extracellular matrix (ECM) derived components are emerging sources for the engineering of biomaterials that are capable of inducing desirable cell-specific responses. This review explores the use of biomaterials derived from naturally occurring ECM proteins and their derivatives in approaches that aim to regulate cell function. Biomaterials addressed are grouped into six categories: purified single ECM proteins, combinations of purified ECM proteins, cell-derived ECM, tissue-derived ECM, diseased and modified ECM, and ECM-polymer coupled biomaterials. Purified ECM proteins serve as a material coating for enhanced cell adhesion and biocompatibility. Cell-derived and tissue-derived ECM, generated by cell isolation and decellularization technologies, can capture the native state of the ECM environment and guide cell migration and alignment patterns as well as stem cell differentiation. We focus primarily on recent advances in the fields of soft tissue, cardiac, and dermal repair, and explore the utilization of ECM proteins as biomaterials to engineer cell responses.

Electrospun Nanofibers for Improved Angiogenesis: Promises for Tissue Engineering Applications

Angiogenesis (or the development of new blood vessels) is a key event in tissue engineering and regenerative medicine; thus, a number of biomaterials have been developed and combined with stem cells and/or bioactive molecules to produce three-dimensional (3D) pro-angiogenic constructs. Among the various biomaterials, electrospun nanofibrous scaffolds offer great opportunities for pro-angiogenic approaches in tissue repair and regeneration. Nanofibers made of natural and synthetic polymers are often used to incorporate bioactive components (e.g., bioactive glasses (BGs)) and load biomolecules (e.g., vascular endothelial growth factor (VEGF)) that exert pro-angiogenic activity. Furthermore, seeding of specific types of stem cells (e.g., endothelial progenitor cells) onto nanofibrous scaffolds is considered as a valuable alternative for inducing angiogenesis. The effectiveness of these strategies has been extensively examined both in vitro and in vivo and the outcomes have shown promise in the reconstruction of hard and soft tissues (mainly bone and skin, respectively). However, the translational of electrospun scaffolds with pro-angiogenic molecules or cells is only at its beginning, requiring more research to prove their usefulness in the repair and regeneration of other highly-vascularized vital tissues and organs. This review will cover the latest progress in designing and developing pro-angiogenic electrospun nanofibers and evaluate their usefulness in a tissue engineering and regenerative medicine setting.