Macrophage Related Chronic Inflammation in Non-Healing Wounds

Precision exosome engineering for enhanced wound healing and scar revision

The dysfunction of wound-healing processes can result in chronic non-healing wounds and pathological scar formation. Current treatment options often fall short, necessitating innovative approaches. Exosomes, extracellular vesicles secreted by various cells, have emerged as promising therapeutic agents serving as an intercellular communication system. By engineering exosomes, their cargo and surface properties can be tailored to enhance therapeutic efficacy and specificity. Engineered exosomes (eExo) are emerging as a favorable tool for treating non-healing wounds and pathological scars. In this review, we delve into the underlying mechanisms of non-healing wounds and pathological scars, outline the current state of engineering strategies, and explore the clinical potential of eExo based on preclinical and clinical studies. In addition, we address the current challenges and future research directions, including standardization, safety and efficacy assessments, and potential immune responses. In conclusion, eExo hold great promise as a novel therapeutic approach for non-healing wounds and non-healing wounds and pathological scars. Further research and clinical trials are warranted to translate preclinical findings into effective clinical treatments.

A preliminary study on the promotion of wound healing by paeoniflorin carbon dots loaded in chitosan hydrogel

Due to poor angiogenesis under the wound bed, wound treatment remains a clinical challenge. Therefore, there is an urgent need for new dressings to combat bacterial infections, accelerate angiogenesis, and accelerate wound healing. In this study, we prepared carbon dots nanomaterial (PF-CDs) derived from traditional Chinese medicine paeoniflorin using a simple green one pot hydrothermal method. The average particle size of the CSs we prepared was 4 nm, and a concentration of 200 μg ml-1was ultimately selected for experiments. Subsequently, PF-CDs were loaded into the chitosan hydrogel to form a new type of wound dressing CSMA@PF-CDs hydrogel. CSMA@PF-CDs demonstrated positive biocompatibility by promoting a 20% increase in cell proliferation and strong antibacterial activity. In comparison to the control group, CSMA@PF-CDs enhanced the expression level of anti-inflammatory factors by at least 2.5 times and reduces the expression level of pro-inflammatory factors by at least 3 times. Furthermore, CSMA@PF-CDs promoted the migration of Human umbilical vein endothelial cells and increased vascular endothelial growth factor expression by 5 times. The results ofin vivoexperiments indicate that CSMA@PF-CDs significantly promoted the healing of back wounds in rats. These characteristics make it a promising material for repairing infected wounds and a potential candidate for clinical skin regeneration applications.

Insulin/PHMB-grafted sodium alginate hydrogels improve infected wound healing by antibacterial-prompted macrophage inflammatory regulation

BACKGROUND

Non-healing chronic wounds with high susceptibility to infection represent a critical challenge in modern healthcare. While growth factors play a pivotal role in regulating chronic wound repair, their therapeutic efficacy is compromised in infected microenvironments. Current wound dressings inadequately address the dual demands of sustained bioactive molecule delivery and robust antimicrobial activity.

RESULTS

In this study, we developed a sodium alginate hydrogel (termed P-SA/Ins), which incorporated polyhexamethylene biguanide (PHMB) grafting and long-acting glargine insulin loading. P-SA/Ins exhibited the favorable physicochemical performance, biocompatibility and antibacterial efficacy against both Gram-negative and Gram-positive pathogens through inhibition of bacterial proliferation and biofilm formation. Glargine insulin was applied to prolonged insulin delivery. P-SA/Ins treatment attenuated S. aureus induced pro-inflammatory cytokine cascades in macrophages. The evaluation in vivo using a rat model with S. aureus infected wound demonstrated that P-SA/Ins significantly enhanced wound healing and optimized skin barrier through antimicrobial-mediated modulation of macrophage polarization and subsequent inflammatory cytokine profiling.

CONCLUSIONS

Our findings demonstrate that P-SA/Ins promotes wound healing and restores epidermal barrier integrity, indicating its potential as a therapeutic dressing for chronic wound healing, particularly in cases with infection risk.

Diabetic Foot Ulcers: Pathophysiology, Immune Dysregulation, and Emerging Therapeutic Strategies

Diabetic foot ulcers (DFUs) are among the most common and debilitating complications of diabetes mellitus (DM), affecting approximately 15-25% of patients and contributing to over 85% of non-traumatic amputations. DFUs impose a substantial clinical and economic burden due to high recurrence rates, prolonged wound care, and frequent hospitalizations, accounting for billions in healthcare costs worldwide. The multifactorial pathophysiology of DFUs involves peripheral neuropathy, peripheral arterial disease, chronic inflammation, and impaired tissue regeneration. Recent studies underscore the importance of immune dysregulation-specifically macrophage polarization imbalance, regulatory T cell dysfunction, and neutrophil impairment-as central mechanisms in wound chronicity. These immune disruptions sustain a pro-inflammatory environment dominated by cytokines, such as TNF-α, IL-1β, and IL-6, which impair angiogenesis and delay repair. This review provides an updated synthesis of DFU pathogenesis, emphasizing immune dysfunction and its therapeutic implications. We examine emerging strategies in immunomodulation, regenerative medicine, and AI-based wound technologies, including SGLT2 inhibitors, biologics, stem cell therapies, and smart dressing systems. These approaches hold promise for accelerating healing, reducing amputation risk, and personalizing future DFU care.

A Self-Assembled Nanoreactor for Realizing Antibacterial Photodynamic/Gas Therapy and Promoting Wound Healing

Among various treatments employed to solve the global problem of bacterial infection, photodynamic therapy (PDT) is recognized as a method with great potential to inactivate a wide range of bacteria without the development of drug resistance. However, many commonly used photosensitizers (PSs) have the disadvantages of poor water-solubility and potential toxicity, which limits their clinical application. Additionally, nitric oxide (NO) has unique advantages in antibacterial treatments due to its small molecular weight. Herein, protoporphyrin IX (PpIX), L-arginine (L-Arg), and glycol chitosan (GC) are used to construct a self-assembled cationic Arg-GC-PpIX nanoreactor for efficient bacterial inactivation under white light illumination. The Arg-GC-PpIX nanoreactor with excellent water dispersity and stability can rapidly bind to bacteria through electrostatic interaction and produce local singlet oxygen (1O2)/NO under light irradiation, leading to a high antibacterial efficiency toward both Gram-negative and Gram-positive bacteria. Besides, these NPs also possess a desirable antibiofilm ability. Finally, Arg-GC-PpIX@Gel which is obtained through loading Arg-GC-PpIX into the sodium alginate (SA)/Ca2+ hydrogel shows a satisfactory ability to promote infected wound healing when combined with white light irradiation. Therefore, the rationally designed Arg-GC-PpIX nanoreactor with light-triggered 1O2/NO release is a promising antibacterial agent for achieving effective PDT/NO gas therapy.

Exosomes from miR-21-5p-modified adipose-derived stem cells promote wound healing by regulating M2 macrophage polarization in a rodent model of pressure ulcer

Pressure ulcers represent a significant healthcare burden worldwide. Numerous research has demonstrated the therapeutic potential of adipose-derived stem cell (ADSC)-derived exosomes in promoting wound healing. This study aims to investigate whether exosomes derived from miRNA-modified ADSCs play a role in pressure ulcers by affecting inflammation and macrophage polarization. ADSCs were identified by detecting the surface markers and multilineage differentiation potential. Lentiviruses carrying miR-21-5p were transduced in ADSCs for stable overexpression. Exosomes were extracted from ADSCs and identified. RT-qPCR was employed to detect RNA levels. A mouse model of pressure ulcers was established, followed by injection of exosomes. DiO staining was conducted to assess exosome biodistribution at wound sites. Hematoxylin-eosin and Masson staining were conducted for histological analysis. Immunofluorescence staining was used to evaluate TNF-α and IL-6 expression in mouse wound tissues. Western blotting was conducted to evaluate protein levels of macrophage polarization markers in vivo and in vitro. The results revealed that exosomes derived from miR-21-5p-overexpressing ADSCs promoted wound healing and reduced inflammatory cytokine expression in mouse wound tissues. Moreover, exosomal miR-21-5p induced macrophage M2 polarization in both mouse wound tissues and bone marrow-derived macrophages. Mechanistically, exosomal miR-21-5p inhibited NF-κB signal transduction in mouse wound tissues. In conclusion, ADSC-derived exosomes promote M2 macrophage polarization and inhibit inflammatory response in pressure ulcers via miR-21-5p delivery.

The bone microenvironment: new insights into the role of stem cells and cell communication in bone regeneration

Mesenchymal stem cells (MSCs) play a crucial role in bone formation and remodeling. Intrinsic genetic factors and extrinsic environmental cues regulate their differentiation into osteoblasts. Within the bone microenvironment, a complex network of biochemical and biomechanical signals orchestrates bone homeostasis and regeneration. In addition, the crosstalk among MSCs, immune cells, and neighboring cells-mediated by extracellular vesicles and non-coding RNAs (such as circular RNAs and micro RNAs) -profoundly influences osteogenic differentiation and bone remodeling. Recent studies have explored specific signaling pathways that contribute to effective bone regeneration, highlighting the potential of manipulating the bone microenvironment to enhance MSC functionality. The integration of advanced biomaterials, gene editing techniques, and controlled delivery systems is paving the way for more targeted and efficient regenerative therapies. Furthermore, artificial intelligence could improve bone tissue engineering, optimize biomaterial design, and enable personalized treatment strategies. This review explores the latest advancements in bone regeneration, emphasizing the intricate interplay among stem cells, immune cells, and signaling molecules. By providing a comprehensive overview of these mechanisms and their clinical implications, we aim to shed light on future research directions in this rapidly evolving field.

Exosome-loaded tannic acid-thioctic acid hydrogel enhances wound healing in coagulation disorders

Hemophilia poses distinct challenges to wound healing, primarily due to uncontrolled bleeding and delayed tissue repair. This study explored a novel tannic acid-thioctic acid (TATA) hydrogel, enriched with exosomes derived from bone marrow mesenchymal stem cells, as a therapeutic strategy for enhancing skin wound healing in a hemophilia model. The hydrogel exhibited robust hemostatic efficacy, potent antioxidant activity, and the capacity to modulate the inflammatory microenvironment. Both in vitro and in vivo assessments demonstrated significantly accelerated wound closure, increased collagen deposition, and pronounced angiogenesis in the TATA Hydrogel-Exosome(TATA Hydrogel-Exos) treatment group relative to controls. Rheological evaluations confirmed the self-healing properties and mechanical durability, of the hydrogel, underscoring its potential for sustained therapeutic application. Importantly, no significant systemic toxicity was observed, indicating favorable biocompatibility. These multifunctional TATA Hydrogel-Exos present a promising therapeutic avenue for hemophilia-related wounds by integrating hemostasis, inflammation regulation, and tissue regeneration.

Enhanced Bioprinting of 3D Corneal Stroma Patches with Reliability, Assessing Product Consistency and Quality through Optimized Electron Beam Sterilization

This study focuses on the optimization of sterilization methods for bioprinted three-dimensional (3D) corneal stroma patches prepared using cornea-derived decellularized extracellular matrix (Co-dECM) hydrogels and human keratocytes, with the aim of enhancing clinical applications in corneal tissue engineering. An essential aspect of this study is to refine the sterilization processes, particularly focusing on electron beam (EB) sterilization, to maintain the structural and functional integrity of the Co-dECM hydrogels while ensuring sterility. The study reveals that EB sterilization outperformed traditional methods like ethylene oxide (EtO) gas and autoclaving, which tend to degrade the biochemical properties of hydrogels. By optimizing the EB-sterilization process, the essential mechanical and biochemical characteristics needed for successful 3D bioprinting are retained, reducing batch variability in bioprinted 3D corneal stroma patches. Consistency in production is vital for meeting regulatory standards and ensuring patient safety. Moreover, the study investigates the immunomodulatory properties of sterilized hydrogels, emphasizing their potential to minimize inflammatory responses, which is crucial for maintaining keratocyte phenotype. These findings significantly advance biomedical engineering by providing a sterilization method that preserves material integrity, minimizes immunogenicity, and supports the clinical translation of bioprinted corneal stroma patches, offering a promising alternative to donor transplants and synthetic substitutes.

Dexketoprofen-Loaded Alginate-Grafted Poly(N-vinylcaprolactam)-Based Hydrogel for Wound Healing

All acute and chronic wound management strategies have limitations. Therefore, there is an urgent need to develop new treatment options for wound healing. Hydrogels based on natural polymers offer advantages in wound management because they can reduce patients' pain, fight infection, and carry targeted drugs to speed up the healing process. In this study, we aimed to develop and investigate an alginate-grafted N-vinylcaprolactam-based matrix for a modified release of dexketoprofen (DEX), which is potentially useful in wound healing. Free radical polymerization and grafted techniques were used to prepare thermo-responsive hydrogels. The obtained hydrogels, unloaded hydrogel (HY) and dexketoprofen-loaded hydrogel (DEXHY), were characterized and analyzed. The concentration of DEX encapsulated in the polymer matrix was 4 mg/mL. The IC50 values found for the samples tested by us were 607.4 µg/mL for HY, 950.4 µg/mL for DEXHY, and 2239 µg/mL for DEX. The average value of cell viability (%) after the exposure of cells to DEXHY hydrogel was 75.4%. DEXHY exhibited a very good in vitro wound closure rate, given its ability to modify DEX release kinetics. The hydrogel developed in this study has shown considerable potential to facilitate and even accelerate wound healing, including surgical wounds, by inhibiting the overexpressed inflammation process.

Advancement of Nanomaterials- and Biomaterials-Based Technologies for Wound Healing and Tissue Regenerative Applications

Patients and healthcare systems face significant social and financial challenges due to the increasing number of individuals with chronic external and internal wounds that fail to heal. The complexity of the healing process remains a serious health concern, despite the effectiveness of conventional wound dressings in promoting healing. Recent advancements in materials science and fabrication techniques have led to the development of innovative dressings that enhance wound healing. To further expedite the healing process, novel approaches such as nanoparticles, 3D-printed wound dressings, and biomolecule-infused dressings have emerged, along with cell-based methods. Additionally, gene therapy technologies are being harnessed to generate stem cell derivatives that are more functional, selective, and responsive than their natural counterparts. This review highlights the significant potential of biomaterials, nanoparticles, 3D bioprinting, and gene- and cell-based therapies in wound healing. However, it also underscores the necessity for further research to address the existing challenges and integrate these strategies into standard clinical practice.

Skin regenerative potential of hydrogel matrices incorporated with stem cell-derived extracellular vesicles enriched with MicroRNAs: a systematic review

Stem cell-derived extracellular vesicles (SC-EVs) are one huge promise in skin regenerative medicine, similar in advantages to stem cells with low immunerejection and tumor formations. These microvesicles are laden with microRNAs, which assist in wound healing via angiogenesis and immune modulation. However, quick degradation and poor cellular uptake limit their regenerative capacity. Thanks to their adjustable characteristics, hydrogels can act as vehicles for transporting and sustainably releasing miRNA-SC-EVs at injury sites. Therefore, a systematic literature review was conducted on miRNA-enriched SC-EVs incorporated into hydrogels in animal skin regeneration models published from 2010 to 2024 (PROSPERO ID: CRD42024588072). Out of the 89 records, 12 met the criteria. Diabetic wounds are characterized by chronic inflammation, oxidative stress, and defective macrophage polarization, resulting in less satisfactory regeneration. The hydrogels tackled these issues by shifting macrophages from a pro-inflammatory M1 phenotype to a healing M2 phenotype, promoting collagen production, enhancing fibroblast movement, and boosting angiogenesis. Burn injuries frequently lead to slow recovery due to hypertrophic scarring, extended inflammation, and infection. Hyaluronic acid (HA)-derived hydrogels, infused with miR-21-5p and surface-treated with polydopamine and cationic antimicrobial peptides, promoted wound healing by lowering scarring and demonstrating anti-inflammatory, anti-apoptotic, and pro-angiogenic characteristics. The cell adhesion of these hydrogels can be enhanced by adding MOFs, chitosan, and extracellular matrix elements. The application of stimulus-responsive or stage-specific hydrogels is another mode of targeted healing. Further research and clinical trials will enhance the wound-healing efficiency of hybrid hydrogels.

Nanomanaging Chronic Wounds with Targeted Exosome Therapeutics

Chronic wounds pose a significant healthcare challenge, impacting millions of patients worldwide and burdening healthcare systems substantially. These wounds often occur as comorbidities and are prone to infections. Such infections hinder the healing process, complicating clinical management and proving recalcitrant to therapy. The environment within the wound itself poses challenges such as lack of oxygen, restricted blood flow, oxidative stress, ongoing inflammation, and bacterial presence. Traditional systemic treatment for such chronic peripheral wounds may not be effective due to inadequate blood supply, resulting in unintended side effects. Furthermore, topical applications are often impervious to persistent biofilm infections. A growing clinical concern is the lack of effective therapeutic modalities for treating chronic wounds. Additionally, the chemically harsh wound microenvironment can reduce the effectiveness of treatments, highlighting the need for drug delivery systems that can deliver therapies precisely where needed with optimal dosages. Compared to cell-based therapies, exosome-based therapies offer distinct advantages as a cell-free approach for chronic wound treatment. Exosomes are of endosomal origin and enable cell-to-cell communications, and they possess benefits, including biocompatibility and decreased immunogenicity, making them ideal vehicles for efficient targeting and minimizing off-target damage. However, exosomes are rapidly cleared from the body, making it difficult to maintain optimal therapeutic concentrations at wound sites. The hydrogel-based approach and development of biocompatible scaffolds for exosome-based therapies can be beneficial for sustained release and prolong the presence of these therapeutic exosomes at chronic wound sites. Engineered exosomes have been shown to possess stability and effectiveness in promoting wound healing compared to their unmodified counterparts. Significant progress has been made in this field, but further research is essential to unlock their clinical potential. This review seeks to explore the benefits and opportunities of exosome-based therapies in chronic wounds, ensuring sustained efficacy and precise delivery despite the obstacles posed by the wound environment.

Radiation-induced lung injury: from mechanism to prognosis and drug therapy

Radiation induced lung injury, known as the main complication of thoracic radiation, remains to be a major resistance to tumor treatment. Based on the recent studies on radiation-induced lung injury, this review collated the possible mechanisms at the level of target cells and key pathways, corresponding prognostic models including predictors, patient size, number of centers, radiotherapy technology, construction methods and accuracy, and pharmacotherapy including drugs, targets, therapeutic effects, impact on anti-tumor treatment and research types. The research priorities and limitations are summarized to provide a reference for the research and management of radiation-induced lung injury.

Interleukin-37 promotes wound healing in diabetic mice by inhibiting the MAPK/NLRP3 pathway

AIMS/INTRODUCTION

Diabetic foot ulcer (DFU) is a prevalent complication of diabetes characterized by heightened inflammation and impaired wound-healing processes. Interleukin-37 (IL-37) is a natural suppressor of innate inflammation. Here, we aim to investigate the potential of IL-37 in enhancing the healing process of diabetic wounds.

MATERIALS AND METHODS

The skin samples of DFU and non-diabetic patients during foot and ankle orthopedic surgery were collected. The IL-37 transgenic mice (IL-37Tg) were created using CRISPR/Cas-mediated genome engineering. Mice were administered streptozotocin (STZ, 150 mg/kg) to induce a diabetic model. After 4 weeks, an equidistant full-thickness excisional wound measuring 8 mm was created on the central back of each mouse and allowed to heal naturally. Body weight and blood glucose levels were measured weekly. The wound area was measured, and skin samples were collected on Day 10 for further Quantitative polymerase chain reaction (qPCR) and WB detection and RNA sequencing analysis.

RESULTS

The proinflammation cytokines such as TNF-α and IL-1β and the MAPK signaling pathway were significantly increased in the wound margin of DFU patients. Compared with diabetic mice, diabetic IL-37Tg mice showed a significantly accelerated healing process. The enriched signaling pathways in RNA sequencing included cytokine-cytokine receptor interaction, TNF signaling pathway, and NOD-like receptor signaling pathway. Through QPCR and WB detection, we found that IL-37 could inhibit the activated MAPK and NOD-like signaling pathway, reducing TNF-α, IL-1β, and NLRP3 expression in the diabetic wound.

CONCLUSIONS

IL-37 promotes skin wound healing in diabetic mice, providing a new possible target for treating diabetic wounds.

Therapeutic Properties of M2 Macrophages in Chronic Wounds: An Innovative Area of Biomaterial-Assisted M2 Macrophage Targeted Therapy

Wound healing is a dynamic, multi-stage process essential for restoring skin integrity. Dysregulated wound healing is often linked to impaired macrophage function, particularly in individuals with chronic underlying conditions. Macrophages, as key regulators of wound healing, exhibit significant phenotypic diversity, ranging from the pro-healing M2 phenotype to the pro-inflammatory M1 phenotype. Imbalances in the M1/M2 ratio or hyperactivation of the M1 phenotype can delay the normal healing. Consequently, strategies aimed at suppressing the M1 phenotype or promoting the shift of local skin macrophages toward the M2 phenotype can potentially treat chronic non-healing wounds. This manuscript provides an overview of macrophages' role in normal and pathological wound-healing processes. It examines various therapeutic approaches targeting M2 macrophages, such as ex vivo-activated macrophage therapy, immunopharmacological strategies, and biomaterial-directed macrophage polarization. However, it also highlights that M2 macrophage therapies and immunopharmacological interventions may have drawbacks, including rapid phenotypic changes, adverse effects on other skin cells, biotoxicity, and concerns related to biocompatibility, stability, and drug degradation. Therefore, there is a need for more targeted macrophage-based therapies that ensure optimal biosafety, allowing for effective reprogramming of dysregulated macrophages and improved therapeutic outcomes. Recent advances in nano-biomaterials have demonstrated promising regenerative potential compared to traditional treatments. This review discusses the progress of biomaterial-assisted macrophage targeting in chronic wound repair and addresses the challenges faced in its clinical application. Additionally, it explores novel design concepts for combinational therapies, such as incorporating regenerative particles like exosomes into dressing materials or encapsulating them in microneedling systems to enhance wound healing rates.

Isolation, identification, and challenges of extracellular vesicles: emerging players in clinical applications

Extracellular vesicles (EVs) serve as critical mediators of intercellular communication, encompassing exosomes, microvesicles, and apoptotic vesicles that play significant roles in diverse physiological and pathological contexts. Numerous studies have demonstrated that EVs derived from mesenchymal stem cells (MSC-EVs) play a pivotal role in facilitating tissue and organ repair, alleviating inflammation and apoptosis, enhancing the proliferation of endogenous stem cells within tissues and organs, and modulating immune function-these functions have been extensively utilized in clinical applications. The precise classification, isolation, and identification of MSC-EVs are essential for their clinical applications. This article provides a comprehensive overview of the biological properties of EVs, emphasizing both their advantages and limitations in isolation and identification methodologies. Additionally, we summarize the protein markers associated with MSC-EVs, emphasizing their significance in the treatment of various diseases. Finally, this article addresses the current challenges and dilemmas in developing clinical applications for MSC-EVs, aiming to offer valuable insights for future research.

B cells recruitment promotes M2 macrophage polarization to inhibit inflammation during wound healing

Wound healing causes heavy economic burdens for families and society, becoming a critical issue in the global healthcare system. While the role of immune cells in the wound-healing process is well-established, the involvement of B cells remains poorly understood. This study aims to elucidate the essentiality of B cells in wound repair. Our findings demonstrate a rise in B-cell population during the early stage of wound healing, which further intensifies during the later stage. We employed anti-CD20 antibodies to deplete B cells in mice and created a whole skin excisional wound mice model, analyzing wound closure over 12 days. B cells were isolated from the animals' spleen and co-cultured with macrophages from bone marrow. The polarization of M1 and M2 macrophages was analyzed by real-time qPCR and flow cytometry. The wound healing process in mice was observed to be considerably delayed following the elimination of B cells. The wounds exhibited a state of inflammation primarily characterized by the presence of pro-inflammatory M1 macrophages. The decrease in M2 macrophages within the local wound area resulted in impairment of the wound repair mechanism. B-cell-macrophage co-culture system revealed that B cells effectively induce the polarization of macrophages towards M2-like phenotype. Furthermore, we found that follicular B cells play predominant role in modulating the polarization of M2 macrophages. Consequently, our findings indicate that B cells can be recruited to the wound site and facilitate the polarization of M2-like macrophages, thereby accelerating the healing process during wound healing.

Vascularization, Innervation, and Inflammation: Pathways Connecting the Heart-Brain Axis and Implications in a Clinical Setting

With an aging population, the incidence of both ischemic heart disease and strokes have become the most prevalent diseases globally. These diseases have similar risk factors, such as hypertension, diabetes, and smoking. However, there is also evidence of a relationship between the heart and the brain, referred to as the heart-brain axis. In this relationship, dysfunction of either organs can lead to injury to the other. There are several proposed physiologies to explain this relationship. These theories usually involve vascular, neuromodulatory, and inflammatory processes; however, few articles have explored and compared these different mechanisms of interaction between the heart and brain. A better understanding of the heart-brain axis can inform physicians of current and future treatment and preventive care options in heart and brain pathologies. The relationship between the brain and heart depends on inflammation, vascular anatomy and function, and neuromodulation. The pathways connecting these organs often become injured or dysfunctional when a major pathology, such as a myocardial infarction or stroke, occurs. This leads to long-term impacts on the patient's overall health and risk for future disease. This study summarizes the current research involved in the heart-brain axis, relates these interactions to different diseases, and proposes future research in the field of neurocardiology. Conditions of the brain and heart are some of the most prevalent diseases. Through understanding the connection between these two organs, we can help inform patients and physicians of novel therapeutics for these pathologies.

Study of an arginine- and tryptophan-rich antimicrobial peptide in peri-implantitis

The combination of hydrophilic arginine residues and hydrophobic tryptophan residues is considered to be the first choice for designing short-chain antimicrobial peptides (AMPs) due to their potent antibacterial activity. Based on this, we designed an arginine- and tryptophan-rich short peptide, VR-12. Peri-implantitis is a significant microbial inflammatory disorder characterized by the inflammation of the soft tissues surrounding an implant, which ultimately leads to the progressive resorption of the alveolar bone. This study found through antibacterial experiments, wound healing promotion experiments, and anti-inflammatory experiments that VR-12 inhibited and killed planktonic peri-implantitis-associated bacteria, inhibited biofilm formation, and disrupted mature biofilms. Additionally, VR-12 exhibited good biocompatibility with RAW264.7 cells and human gingival fibroblasts (HGFs) cells, promoting proliferation of both cell types. Moreover, VR-12 induced HGFs migration by promoting expression of migration-related factors, thereby promoting soft tissue healing. VR-12 also acted on lipopolysaccharide (LPS)-induced RAW264.7 cells, exerting excellent anti-inflammatory properties by affecting the secretion/expression of inflammation-related factors/genes. Therefore, VR-12 may be a good option for both warding off and treatmenting peri-implantitis.

Macrophage STING signaling promotes fibrosis in benign airway stenosis via an IL6-STAT3 pathway

Acute and chronic inflammation are important pathologies of benign airway stenosis (BAS) fibrosis, which is a frequent complication of critically ill patients. cGAS-STING signalling has an important role in inflammation and fibrosis, yet the function of STING in BAS remains unclear. Here we demonstrate using scRNA sequencing that cGAS‒STING signalling is involved in BAS, which is accompanied by increased dsDNA, expression and activation of STING. STING inhibition or deficiency effectively alleviates tracheal fibrosis of BAS mice by decreasing both acute and chronic inflammation. Macrophage depletion also effectively ameliorates BAS. Mechanistically, dsDNA from damaged epithelial cells activates the cGAS-STING pathway of macrophages and induces IL-6 to activate STAT3 and promote fibrosis. In summary, the present results suggest that cGAS-STING signalling induces acute inflammation and amplifies the chronic inflammation and tracheal fibrosis associated with benign airway stenosis, highlighting the mechanism and potential drug target of BAS.

Epigenetic regulatory mechanism of macrophage polarization in diabetic wound healing (Review)

Diabetic wounds represent a significant complication of diabetes and present a substantial challenge to global public health. Macrophages are crucial effector cells that play a pivotal role in the pathogenesis of diabetic wounds, through their polarization into distinct functional phenotypes. The field of epigenetics has emerged as a rapidly advancing research area, as this phenomenon has the potential to markedly affect gene expression, cellular differentiation, tissue development and susceptibility to disease. Understanding epigenetic mechanisms is crucial to further exploring disease pathogenesis. A growing body of scientific evidence has highlighted the pivotal role of epigenetics in the regulation of macrophage phenotypes. Various epigenetic mechanisms, such as DNA methylation, histone modification and non‑coding RNAs, are involved in the modulation of macrophage phenotype differentiation in response to the various environmental stimuli present in diabetic wounds. The present review provided an overview of the various changes that take place in macrophage phenotypes and functions within diabetic wounds and discussed the emerging role of epigenetic modifications in terms of regulating macrophage plasticity in diabetic wounds. It is hoped that this synthesis of information will facilitate the elucidation of diabetic wound pathogenesis and the identification of potential therapeutic targets.

[Phage therapy analysis of effectiveness in comorbid patients with wounds and surgical infections of various etiology based on the results of a comparative clinical study]

BACKGROUND

The continued importance of addressing the issue of treating purulent wounds and surgical infections of different origins and localization against the background of increased resistance of their main pathogens dictates the need to develop alternative protocols and search for new treatment strategies, the effectiveness of which is confirmed by objective diagnostic methods.

OBJECTIVE

The aim of the study was to analyze the effectiveness of phage therapy in comparison with traditional methods of local drug and systemic treatment in comorbid patients with surgical infection of various etiologies and localization by studying the microbiological spectrum, cytology of wound impressions and morphological, including electron microscopic examination of tissue biopsies.

MATERIAL AND METHODS

The results of the research are presented: a post-marketing, prospective, randomized, comparative clinical trial enrolling 70 adult patients with complicated skin, soft tissue, and bone infections of various etiologies and localizations, conducted at the Department of Wounds and Wound Infections, National Medical Research Center for Surgery named after A. Vishnevsky, Ministry of Health of the Russian Federation. During the study, clinical (edema, pain, the nature of wound discharge, the appearance of granulation tissue), laboratory (the presence and regression of signs of a systemic response to the presence of a surgical infection), microbiological (qualitative and quantitative), cytological and electron microscopic parameters were analyzed in all patients. Parametric data were evaluated based on the mean and standard deviation (SD) at 4 study points: point 1 (2±1 days), point 2 (4±1 days), point 3 (6±1 days) and point 4 (8±1 days). The key endpoint was the transition of the wound process into the regeneration phase.

RESULTS

According to the study protocol, all the patients included in the analysis had purulent-necrotic wounds of soft tissues and bones different etiology and localization, requiring surgical debridement. To randomize patients into groups, upon admission or intraoperatively, material was collected for qualitative and quantitative microbiological, cytological, morphological and electron microscopic studies. Randomization into groups of bacteriophages was possible in the presence of sensitivity of isolated cultures to the "Piobacteriophage complex" liquid (Piofag, JSC NPO Microgen, Russia). In the postoperative period, patients of group 1 (n=20) received systemic and local phage therapy (20 ml 3 times a day, according to the instructions), in group 2 (n=20) - systemic and local phage therapy, combined with local negative pressure (-120 mmHg, constant mode), delivery of bacteriophages to the surgical infection site was carried out using VitMobil instillation (VitMedical, Russia), systemic (levofloxacin 500 mg twice a day) and local (multicomponent polythylene glycol-based ointment with fluoroquinolones - Oflomelid, Russia) antibacterial therapy was performed in group 3 (n=30). An analysis of the treatment results indicates the high effectiveness of the proposed protocol in all study groups. In group 2 (local negative pressure with bacteriophage instillation in combination with systemic phage therapy) the best microbiological, cytological, histological and clinical efficacy was noted, indicating the potentiation of both methods of treating purulent wounds of various etiology and localization (the first signs of relief of the inflammatory phase were noted by 4±1 days after surgery). In general, key endpoints (the transition of the wound process to the regeneration phase) were achieved in all the studied groups with good tolerability of therapy and a high safety profile. No additional surgical interventions were required in any group, and no deaths were reported. No adverse events requiring discontinuation or change of treatment option have been reported. Based on the results obtained, the use of Pyobacteriophage complex liquid can be recommended for the complex treatment of purulent-necrotic wounds of various etiologies and localization in the presence of multiple antibiotic resistance, as well as in cases where systemic antibacterial therapy is contraindicated. The most effective is a combination of general and local phage therapy by various delivery routes (in particular, using vacuum devices with the possibility of instillation).

CONCLUSION

The principles of treatment of soft tissues and bones severe surgical infection in comorbid patients in our country are still based on the method of active surgical treatment of wounds developed in the Department of Wounds and Wound Infections of the Vishnevsky Institute of Surgery (now, the Vishnevsky National Research Medical Center of Surgery of the Ministry of Health of the Russian Federation). In relation to the first phase of wound healing, the results of treatment will largely depend on the radicality and thoroughness of the primary surgical debridement of the purulent focus, general and local treatment in the perioperative period. The increasing problem of resistance, the formation of biofilm forms of pathogens in chronic wounds, and comorbidity, which limits us to using a number of reserve antibiotics due to their toxicity, determine the importance of finding alternative treatment protocols for such complex clinical situations. The results of the study are encouraging and demonstrate that practical healthcare should continue to pay attention to the study and use of bacteriophage drugs in the complex treatment of surgical infection. It is necessary to look for new ways to deliver these drugs directly to the infection site in order to maintain their optimal concentration and activity.

Comparison of cell-scaffold interactions in a biological and a synthetic wound matrix

Wound healing is a central physiological process that restores the barrier properties of the skin after injury, comprising close coordination between several cell types (including fibroblasts and macrophages) in the wound bed. The complex mechanisms involved are executed and regulated by an equally complex, reciprocal signalling network involving numerous signalling molecules such as catabolic and anabolic inflammatory mediators (e.g., cytokines, chemokines). In chronic wound environments, the balance in the molecular signatures of inflammatory mediators is usually impaired. Thus, we compared the ability of a collagen-based wound matrix against a synthetic wound matrix to attract fibroblasts and macrophages that deliver these signalling molecules. In particular, the balance between pro- and anti- inflammatory cytokine secretion was assessed. We found that the natural collagen-based matrix was the most efficient adhesive substrate to recruit and activate fibroblasts and macrophages on its surface. These cells secreted a variety of cytokines, and the natural biomaterial exhibited a more balanced secretion of pro- and anti-inflammatory mediators than the synthetic comparator. Thus, our study highlights the ability of native collagen matrices to modulate inflammatory mediator signatures in the wound bed, indicating that such devices may be beneficial for wound healing in the clinical setting.

Nanobodies as innovative immune checkpoint modulators: advancing cancer immunotherapy

The immune system relies on a delicate balance between attacking harmful pathogens and preserving the body's own tissues, a balance maintained by immune checkpoints. These checkpoints play a critical role in preventing autoimmune diseases by restraining excessive immune responses while allowing the immune system to recognize and destroy abnormal cells, such as tumors. In recent years, immune checkpoint inhibitors (ICIs) have become central to cancer therapy, enabling the immune system to target and eliminate cancer cells that evade detection. Traditional antibodies, such as IgGs, have been widely used in immune therapies but are limited by their size and complexity. Nanobodies (Nbs), derived from camelid heavy-chain-only antibodies, offer a promising alternative. These small, stable antibody fragments retain the antigen-binding specificity of traditional antibodies but have enhanced solubility and the ability to target otherwise inaccessible epitopes. This review explores the use of Nbs as ICIs, emphasizing their potential in cancer immunotherapy and other immune-related treatments. Their unique structural properties and small size make Nbs highly effective tools for modulating immune responses, representing a novel approach in the evolving landscape of checkpoint inhibitor therapies.

Temperature-Responsive Hydrogel System Integrating Wound Temperature Monitoring and On-demand Drug Release for Sequentially Inflammatory Process Regulation of Wound Healing

Wound healing faces challenges like inflammation, infection, and limited monitoring capabilities, and traditional dressings often lack the ability to promote healing or provide real-time wound status updates. Early pro-inflammatory responses help clear pathogens and damaged tissue, while timely anti-inflammatory modulation aids tissue regeneration, making sequential inflammation regulation crucial. Additionally, wound temperature, a key infection biomarker, enables real-time monitoring for effective management. We propose a temperature-responsive hydrogel dressing capable of two-stage sequential drug release and wound temperature monitoring. The hydrogel, composed of poly(N-isopropylacrylamide) (PNIPAM) and dopamine/methacrylated-modified hyaluronic acid (HA-MA-DA), allows temperature-based drug release control, sequential regulating pro-inflammatory and anti-inflammatory stages in wound healing. Interleukin-8 (IL-8), a pro-inflammatory molecule, is encapsulated into hydrogel matrix and rapidly released to trigger the initial inflammatory response. Furthermore, photothermally responsive and erastin-loaded polydopamine@PNIPAM nanoparticles (E-PD NPs) are incorporated to release the anti-inflammatory drug erastin upon near-infrared light exposure, terminating inflammation through cytosolic burial, and thus achieve anti-inflammatory effects at the second stage of wound healing. Furthermore, a bluetooth module enables real-time wound temperature monitoring. Combining sequential drug release with temperature monitoring, our hydrogel dressing addresses significant gaps in current wound healing technologies and offers new insights into personalized therapeutic interventions.

Macrophage Polarization: A Novel Target and Strategy for Pathological Scarring

BACKGROUND

Abnormal scarring imposes considerable challenges and burdens on the lives of patients and healthcare system. Macrophages at the wound site are found to be of great concern to overall wound healing. There have been many studies indicating an inextricably link between dysfunctional macrophages and fibrotic scars. Macrophages are not only related to pathogen destruction and phagocytosis of apoptotic cells, but also involved in angiogenesis, keratinization and collagen deposition. These abundant cell functions are attributed to specific heterogeneity and plasticity of macrophages, which also add an extra layer of complexity to correlational researches.

METHODS

This article summarizes current understanding of macrophage polarization in scar formation and several prevention and treatment strategies on pathological scarring related to regulation of macrophage behaviors by utilizing databases such as PubMed, Google Scholar and so on.

RESULTS

There are many studies proving that macrophages participate in the course of wound healing by converting their predominant phenotype. The potential of macrophages in managing hypertrophic scars and keloid lesions have been underscored.

CONCLUSION

Macrophage polarization offers new prevention strategies for pathological scarring. Learning about and targeting at macrophages may be helpful in achieving optimum wound healing.

The Immune-Centric Revolution Translated into Clinical Application: Peripheral Blood Mononuclear Cell (PBMNC) Therapy in Diabetic Patients with No-Option Critical Limb-Threatening Ischemia (NO-CLTI)-Rationale and Meta-Analysis of Observational Studies

Chronic limb-threatening ischemia (CLTI), the most advanced form of peripheral arterial disease (PAD), is the comorbidity primarily responsible for major lower-limb amputations, particularly for diabetic patients. Autologous cell therapy has been the focus of efforts over the past 20 years to create non-interventional therapeutic options for no-option CLTI to improve limb perfusion and wound healing. Among the different available techniques, peripheral blood mononuclear cells (PBMNC) appear to be the most promising autologous cell therapy due to physio-pathological considerations and clinical evidence, which will be discussed in this review. A meta-analysis of six clinical studies, including 256 diabetic patients treated with naive, fresh PBMNC produced via a selective filtration point-of-care device, was conducted. PBMNC was associated with a mean yearly amputation rate of 15.7%, a mean healing rate of 62%, and a time to healing of 208.6 ± 136.5 days. Moreover, an increase in TcPO2 and a reduction in pain were observed. All-cause mortality, with a mean rate of 22.2% and a yearly mortality rate of 18.8%, was reported. No serious adverse events were reported. Finally, some practical and financial considerations are provided, which point to the therapy's recommendation as the first line of treatment for this particular and crucial patient group.

The Promoting Effect of Animal Bioactive Proteins and Peptide Components on Wound Healing: A Review

The skin is the first line of defense to protect the host from external environmental damage. When the skin is damaged, the wound provides convenience for the invasion of external substances. The prolonged nonhealing of wounds can also lead to numerous subsequent complications, seriously affecting the quality of life of patients. To solve this problem, proteins and peptide components that promote wound healing have been discovered in animals, which can act on key pathways involved in wound healing, such as the PI3K/AKT, TGF-β, NF-κ B, and JAK/STAT pathways. So far, some formulations for topical drug delivery have been developed, including hydrogels, microneedles, and electrospinning nanofibers. In addition, some high-performance dressings have been utilized, which also have great potential in wound healing. Here, research progress on the promotion of wound healing by animal-derived proteins and peptide components is summarized, and future research directions are discussed.

Dental Pulp Stem Cell Lysate-Based Hydrogel Improves Diabetic Wound Healing via the Regulation of Anti-Inflammatory Macrophages and Keratinocytes

The prolonged existence of chronic wounds heightens the risk of patients experiencing chronic pain, necrosis, and amputation. Dental pulp stem cells (DPSCs) have garnered attention due to their potential immunomodulatory and tissue repair regenerative effects in the management of chronic wounds. However, stem-cell-based therapy faces challenges such as malignant differentiation, immune rejection, and long-term effectiveness. To overcome these challenges, we proposed a chronic wound therapy using a hydrogel derived from human-originated dental pulp stem cell lysate (DPSCL). Our data indicate that, with the degradation of the dental pulp stem cell lysate-based hydrogel (DPSCLH), the slowly released cell lysates recruit anti-inflammatory M2 macrophages and promote the proliferation, migration, and keratinization of HacaT cells. In addition, in vivo studies revealed that DPSCLH avoids immune rejection reactions and induces a long-term accumulation of endogenous M2 macrophages. In a mouse model of diabetic wounds, DPSCLH effectively modulates the inflammatory microenvironment around diabetic wounds, promotes the formation of the stratum corneum, and facilitates the healing of wounds, thus holding tremendous potential for the treatment of diabetic wounds.

Liver Fluke-Derived Molecules Accelerate Skin Repair Processes in a Mouse Model of Type 2 Diabetes Mellitus

Chronic nonhealing wounds, such as diabetic ulcers, are among the most serious complications of diabetes mellitus. Consequently, the search for new therapeutic strategies remains highly relevant. Based on our previous data on acute wounds, bioactive molecules derived from the liver fluke Opisthorchis felineus hold promise as a novel approach to wound healing. The aim of this study was to investigate the wound-healing properties of excretory-secretory products (ESP) and inactivated eggs of O. felineus in a model of type 2 diabetes mellitus. Two-month-old mice of the BKS.Cg + Leprdb/+Leprdb/OlaHsd (db/db) strain were inflicted with superficial wounds of 5 mm in diameter. Mouse groups included several controls (methylcellulose as the vehicle and human recombinant PDGF as the positive control) and specific-treatment groups (ESP and inactivated O. felineus eggs). Histopathological, immunohistochemical, and RT-PCR studies using markers for M1/M2 polarization, angiogenesis, and extracellular matrix remodeling were carried out. Additionally, an image analysis of Masson's trichrome-stained skin sections was performed. The proliferation of HaCaT cells under ESP and egg treatment was also assessed. The present study reveals a significant increase in the percentage of wound healing in ESP- and egg-treated groups, which significantly exceeded the control values after 14 days. Wound treatment with either ESP or worm eggs resulted in (i) a reduction in inflammation with a canonical M1-to-M2 polarization shift, (ii) the modulation of the vascular response, and (iii) dermal extracellular matrix remodeling. All results are comparable to those of the positive control group treated with PDGF. This study also reveals that ESP, but not O. felineus eggs, stimulated keratinocyte proliferation in vitro. The results indicate the high wound-healing potential of liver fluke bioactive molecules and open prospects for further research on these new promising therapeutic approaches.

Regenerative Inflammation: The Mechanism Explained from the Perspective of Buffy-Coat Protagonism and Macrophage Polarization

The buffy-coat, a layer of leukocytes and platelets obtained from peripheral blood centrifugation, plays a crucial role in tissue regeneration and the modulation of inflammatory responses. This article explores the mechanisms of regenerative inflammation, highlighting the critical role of the buffy-coat in influencing macrophage polarization and its therapeutic potential. Macrophage polarization into M1 and M2 subtypes is pivotal in balancing inflammation and tissue repair, with M1 macrophages driving pro-inflammatory responses and M2 macrophages promoting tissue healing and regeneration. The buffy-coat's rich composition of progenitor cells, cytokines, and growth factors-such as interleukin-10, transforming growth factor-β, and monocyte colony-stimulating factor-supports the transition from M1 to M2 macrophages, enhancing tissue repair and the resolution of inflammation. This dynamic interaction between buffy-coat components and macrophages opens new avenues for therapeutic strategies aimed at improving tissue regeneration and managing inflammatory conditions, particularly in musculoskeletal diseases such as osteoarthritis. Furthermore, the use of buffy-coat-derived therapies in conjunction with other regenerative modalities, such as platelet-rich plasma, holds promise for more effective clinical outcomes.

Mangiferin Represses Inflammation in Macrophages Under a Hyperglycemic Environment Through Nrf2 Signaling

Inflammation in macrophages is exacerbated under hyperglycemic conditions, contributing to chronic inflammation and impaired wound healing in diabetes. This study investigates the potential of mangiferin, a natural polyphenol, to alleviate this inflammatory response by targeting a redox-sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2). Mangiferin, a known Nrf2 activator, was evaluated for its ability to counteract the hyperglycemia-induced inhibition of Nrf2 and enhance antioxidant defenses. The protective effects of mangiferin on macrophages in a hyperglycemic environment were assessed by examining the expression of Nrf2, NF-κB, NLRP3, HO-1, CAT, COX-2, IL-6, and IL-10 through gene and protein expression analyses using qPCR and immunoblotting, respectively. The mangiferin-mediated nuclear translocation of Nrf2 was evidenced, leading to a robust antioxidant response in macrophages exposed to a hyperglycemic microenvironment. This activation suppressed NF-κB signaling, reducing the expression of pro-inflammatory mediators such as COX-2 and IL-6. Additionally, mangiferin decreased NLRP3 inflammasome activation and reactive oxygen species accumulation in hyperglycemia exposed macrophages. Our findings revealed that mangiferin alleviated hyperglycemia-induced reductions in AKT phosphorylation, highlighting its potential role in modulating key signaling pathways. Furthermore, mangiferin significantly enhanced the invasiveness and migration of macrophages in a hyperglycemic environment, indicating its potential to improve wound healing. In conclusion, this study suggests that mangiferin may offer a promising therapeutic approach for managing inflammation and promoting wound healing in diabetic patients by regulating Nrf2 activity in hyperglycemia-induced macrophages.

Hypoxic microenvironment promotes diabetic wound healing by polarizing macrophages to the M2 phenotype in vivo

BACKGROUND

In diabetic wounds, M2 polarization of macrophages regulates the transition from an inflammatory phase to a proliferative phase. Prior investigations have demonstrated the potential of deferoxamine (DFO) in creating a localized hypoxic microenvironment, which could stimulate angiogenesis by promoting vascular endothelial growth factor (VEGF) secretion in diabetic wound healing. Nevertheless, there is still no clear information on whether this chemically induced hypoxic microenvironment modulates macrophage polarization to promote diabetic wound healing.

METHODS

The 18 diabetic mice were randomly divided into three groups: a control group (n = 6), a 100µM DFO group (n = 6), and a 200µM DFO group (n = 6). Subsequently, a full-thickness wound with a diameter of 1.00 cm was created on the dorsal region of the diabetic mice. Observe wound closure regularly during treatment. At the end of the observation, tissue specimens were collected for a series of experiments and analyses, including hematoxylin and eosin (H&E), Masson, immunofluorescent, and immunohistochemical staining. The role and mechanism of DFO in regulating macrophage polarization were studied using RAW264.7 cells.

RESULTS

In comparison to the control group, the administration of DFO notably facilitates wound healing in diabetic mice. In diabetic wounds, DFO increases blood supply by upregulating VEGF, which promotes angiogenesis. Additionally, The expression of HSP70 and CD206 were also upregulated by DFO in both vivo and in vitro, while iNOS expression was downregulated. Additionally, knk437 inhibited the expression of HSP70 in RAW264.7 cells, resulting in a reduction of M2 polarization and an increase in M1 polarization.

CONCLUSION

The induction of a hypoxic microenvironment by DFO has been found to exert a substantial influence on the process of diabetic wound healing. DFO treatment enhances the capacity of diabetic wounds to stimulate angiogenesis and modulate macrophage polarization that may be associated with HSP70 expression, thereby expediting the transition of these wounds from an inflammatory to a proliferative state.

Advances and applications of biomimetic biomaterials for endogenous skin regeneration

Endogenous regeneration is becoming an increasingly important strategy for wound healing as it facilitates skin's own regenerative potential for self-healing, thereby avoiding the risks of immune rejection and exogenous infection. However, currently applied biomaterials for inducing endogenous skin regeneration are simplistic in their structure and function, lacking the ability to accurately mimic the intricate tissue structure and regulate the disordered microenvironment. Novel biomimetic biomaterials with precise structure, chemical composition, and biophysical properties offer a promising avenue for achieving perfect endogenous skin regeneration. Here, we outline the recent advances in biomimetic materials induced endogenous skin regeneration from the aspects of structural and functional mimicry, physiological process regulation, and biophysical property design. Furthermore, novel techniques including in situ reprograming, flexible electronic skin, artificial intelligence, single-cell sequencing, and spatial transcriptomics, which have potential to contribute to the development of biomimetic biomaterials are highlighted. Finally, the prospects and challenges of further research and application of biomimetic biomaterials are discussed. This review provides reference to address the clinical problems of rapid and high-quality skin regeneration.

Macrophages and Gut Barrier Function: Guardians of Gastrointestinal Health in Post-Inflammatory and Post-Infection Responses

The gut barrier is essential for protection against pathogens and maintaining homeostasis. Macrophages are key players in the immune system, are indispensable for intestinal health, and contribute to immune defense and repair mechanisms. Understanding the multifaceted roles of macrophages can provide critical insights into maintaining and restoring gastrointestinal (GI) health. This review explores the essential role of macrophages in maintaining the gut barrier function and their contribution to post-inflammatory and post-infectious responses in the gut. Macrophages significantly contribute to gut barrier integrity through epithelial repair, immune modulation, and interactions with gut microbiota. They demonstrate active plasticity by switching phenotypes to resolve inflammation, facilitate tissue repair, and regulate microbial populations following an infection or inflammation. In addition, tissue-resident (M2) and infiltration (M1) macrophages convert to each other in gut problems such as IBS and IBD via major signaling pathways mediated by NF-κB, JAK/STAT, PI3K/AKT, MAPK, Toll-like receptors, and specific microRNAs such as miR-155, miR-29, miR-146a, and miR-199, which may be good targets for new therapeutic approaches. Future research should focus on elucidating the detailed molecular mechanisms and developing personalized therapeutic approaches to fully harness the potential of macrophages to maintain and restore intestinal permeability and gut health.

Preparation of Multifunctional Hydrogels with In Situ Dual Network Structure and Promotion of Wound Healing

As an emerging biomedical material, wound dressings play an important therapeutic function in the process of wound healing. It can provide an ideal healing environment while protecting the wound from a complex external environment. A hydrogel wound dressing composed of tilapia skin gelatin (Tsg) and fucoidan (Fuc) was designed in this article to enhance the microenvironment of wound treatment and stimulate wound healing. By mixing horseradish peroxidase (HRP), hydrogen peroxide (H2O2), tilapia skin gelatin-tyramine (Tsg-Tyr), and carboxylated fucoidan-tyramine in agarose (Aga), using the catalytic cross-linking of HRP/H2O2 and the sol-gel transformation of Aga, a novel gelatin-fucoidan (TF) double network hydrogel wound dressing was constructed. The TF hydrogels have a fast and adjustable gelation time, and the addition of Aga further enhances the stability of the hydrogels. Moreover, Tsg and Fuc are coordinated with each other in terms of biological efficacy, and the TF hydrogel demonstrated excellent antioxidant properties and biocompatibility in vitro. Also, in vivo wound healing experiments showed that the TF hydrogel could effectively accelerate wound healing, reduce wound microbial colonization, alleviate inflammation, and promote collagen deposition and angiogenesis. In conclusion, TF hydrogel wound dressings have the potential to replace traditional dressings in wound healing.

Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure

Chronic wounds affect ~2% of the U.S. population and increase risks of amputation and mortality. Unfortunately, treatments for such wounds are often expensive, complex, and only moderately effective. Electrotherapy represents a cost-effective treatment; however, its reliance on bulky equipment limits its clinical use. Here, we introduce water-powered, electronics-free dressings (WPEDs) that offer a unique solution to this issue. The WPED performs even under harsh conditions-situations wherein many present treatments fail. It uses a flexible, biocompatible magnesium-silver/silver chloride battery and a pair of stimulation electrodes; upon the addition of water, the battery creates a radial electric field. Experiments in diabetic mice confirm the WPED's ability to accelerate wound closure and promote healing by increasing epidermal thickness, modulating inflammation, and promoting angiogenesis. Across preclinical wound models, the WPED-treated group heals faster than the control with wound closure rates comparable to treatments requiring expensive biologics and/or complex electronics. The results demonstrate the WPED's potential as an effective and more practical wound treatment dressing.

Efficacy of MSC-derived small extracellular vesicles in treating type II diabetic cutaneous wounds: a systematic review and meta-analysis of animal models

Background

Small extracellular vesicles derived from mesenchymal stem cells (MSC-sEVs) have emerged as a promising therapy for treating type II diabetic cutaneous wounds. Currently, the evidence supporting the use of MSC-sEVs for treating diabetic skin wounds remains inconclusive and is limited to preclinical studies. To facilitate the clinical translation of cell-free therapy, conducting a comprehensive systematic review of preclinical studies assessing the efficacy of MSC-sEVs is imperative.

Methods

A systematic search was conducted on PubMed, Web of Science, Embase, and Cochrane Library databases until June 14, 2023, to identify studies that met our pre-established inclusion criteria. The outcome indicators comprised wound closure rate (primary outcome), neovascular density, re-epithelialization rate, collagen deposition, and inflammatory factors (secondary Outcomes). A fixed-effects model was employed in instances of low heterogeneity (I2<50%), while a random-effects model was utilized for high heterogeneity (I2≥50%). The risk of bias in animal studies was assessed using the SYRCLE tool.

Results

Twenty-one studies were included in this meta-analysis. Compared with the control group, MSC-sEVs were found to significantly facilitate the healing of cutaneous wounds in type II diabetic patients (standardized mean difference [SMD]=3.16, 95% confidence interval [CI]: 2.65 to 3.66, P<0.00001, I2 = 39%).

Conclusions

According to the meta-analysis of preclinical studies, MSC-sEVs show promising applications in promoting type II diabetic wound healing. As a result, translating these findings into clinical applications appears warranted.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42023375467.

Krill oil: nutraceutical potential in skin health and disease

Krill oil (KO), extracted from the Antarctic marine crustacean Euphausia superba, is a nutrient-dense substance that includes rich profiles of n-3 polyunsaturated fatty acids (n-3 PUFAs), phospholipids (PLs), astaxanthin (ASX), as well as vitamins A and E, minerals, and flavonoids. As a high-quality lipid resource, KO has been widely used as a dietary supplement for its health-protective properties in recent years. KO has various benefits, including antioxidative, anti-inflammatory, metabolic regulatory, neuroprotective, and gut microbiome modulatory effects. Especially, the antioxidant and anti-inflammatory effects make KO have potential in skin care applications. With increasing demands for natural skin anti-aging solutions, KO has emerged as a valuable nutraceutical in dermatology, showing potential for mitigating the effects of skin aging and enhancing overall skin health and vitality. This review provides an overview of existing studies on the beneficial impact of KO on the skin, exploring its functional roles and underlying mechanisms through which it contributes to dermatological health and disease management.

Targeting Macrophage Polarization for Reinstating Homeostasis following Tissue Damage

Tissue regeneration and remodeling involve many complex stages. Macrophages are critical in maintaining micro-environmental homeostasis by regulating inflammation and orchestrating wound healing. They display high plasticity in response to various stimuli, showing a spectrum of functional phenotypes that vary from M1 (pro-inflammatory) to M2 (anti-inflammatory) macrophages. While transient inflammation is an essential trigger for tissue healing following an injury, sustained inflammation (e.g., in foreign body response to implants, diabetes or inflammatory diseases) can hinder tissue healing and cause tissue damage. Modulating macrophage polarization has emerged as an effective strategy for enhancing immune-mediated tissue regeneration and promoting better integration of implantable materials in the host. This article provides an overview of macrophages' functional properties followed by discussing different strategies for modulating macrophage polarization. Advances in the use of synthetic and natural biomaterials to fabricate immune-modulatory materials are highlighted. This reveals that the development and clinical application of more effective immunomodulatory systems targeting macrophage polarization under pathological conditions will be driven by a detailed understanding of the factors that regulate macrophage polarization and biological function in order to optimize existing methods and generate novel strategies to control cell phenotype.

Histone demethylase JARID1C/KDM5C regulates Th17 cells by increasing IL-6 expression in diabetic plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) are first responders to tissue injury, where they prime naive T cells. The role of pDCs in physiologic wound repair has been examined, but little is known about pDCs in diabetic wound tissue and their interactions with naive CD4+ T cells. Diabetic wounds are characterized by increased levels of inflammatory IL-17A cytokine, partly due to increased Th17 CD4+ cells. This increased IL-17A cytokine, in excess, impairs tissue repair. Here, using human tissue and murine wound healing models, we found that diabetic wound pDCs produced excess IL-6 and TGF-β and that these cytokines skewed naive CD4+ T cells toward a Th17 inflammatory phenotype following cutaneous injury. Further, we identified that increased IL-6 cytokine production by diabetic wound pDCs is regulated by a histone demethylase, Jumonji AT-rich interactive domain 1C histone demethylase (JARID1C). Decreased JARID1C increased IL-6 transcription in diabetic pDCs, and this process was regulated upstream by an IFN-I/TYK2/JAK1,3 signaling pathway. When inhibited in nondiabetic wound pDCs, JARID1C skewed naive CD4+ T cells toward a Th17 phenotype and increased IL-17A production. Together, this suggests that diabetic wound pDCs are epigenetically altered to increase IL-6 expression that then affects T cell phenotype. These findings identify a therapeutically manipulable pathway in diabetic wounds.

Lignin-cellulose complexes derived from agricultural wastes for combined antibacterial and tissue engineering scaffolds for cutaneous leishmaniasis wounds

Bacterial infections in wounds significantly impair the healing process. The use of natural antibacterial products over synthetic antibiotics has emerged as a new trend to address antimicrobial resistance. An ideal tissue engineering scaffold to treat infected wounds should possess antibacterial properties, while simultaneously promoting tissue regrowth. Synthesis of hydrogel scaffolds with antibacterial properties using hemp shive (HT1/HT2) lignin, sugarcane bagasse (SCB) lignin and cellulose was carried out. All lignin samples had low molecular weights and were constituted of G-type β-5 dimers, linked by β-O-4 bonds, as determined by MALDI-TOF-MS. Hemp lignin was more cytotoxic to mouse fibroblasts (L929) compared to SCB lignin. All lignin samples demonstrated antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis, with greater efficiency against Gram-negative strains. 3D hydrogels were engineered by crosslinking SCB lignin with SCB cellulose in varying weight ratios in the presence of epichlorohydrin. The stiffness of the hydrogels could be tailored by varying the lignin concentration. All hydrogels were biocompatible; however, better fibroblast adhesion was observed on the blended hydrogels compared to the 100% cellulose hydrogel, with the cellulose : lignin 70 : 30 hydrogel showing the highest L929 proliferation and best antibacterial properties with a 24-hour bacterial growth reduction ranging from 30.8 to 57.3%.

Promoting Diabetic Wound Healing through a Hydrogel-Based Cascade Regulation Strategy of Fibroblast-Macrophage

The management of diabetic wounds (DWs) continues to pose a significant challenge in the field of medicine. DWs are primarily prevented from healing due to damage to macrophage efferocytosis and fibroblast dysfunction. Consequently, a treatment strategy that involves both immunoregulation and the promotion of extracellular matrix (ECM) formation holds promise for healing DWs. Nevertheless, existing treatment methods necessitate complex interventions and are associated with increased costs, for example, the use of cytokines and cell therapy, both of which have limited effectiveness. In this study, a new type of ruthenium (IV) oxide nanoparticles (RNPs)-laden hybrid hydrogel dressing with a double network of Pluronic F127 and F68 has been developed. Notably, the hybrid hydrogel demonstrates remarkable thermosensitivity, injectability, immunoregulatory characteristics, and healing capability. RNPs in hydrogel effectively regulate both fibroblasts and macrophages in a cascade manner, stimulating fibroblast differentiation while synergistically enhancing the efferocytosis of macrophage. The immunoregulatory character of the hydrogel aids in restoring the intrinsic stability of the immune microenvironment in the wound and facilitates essential remodeling of the ECM. This hydrogel therefore offers a novel approach for treating DWs through intercellular communication.

Spermidine-Functionalized Injectable Hydrogel Reduces Inflammation and Enhances Healing of Acute and Diabetic Wounds In Situ

The inflammatory response is a key factor affecting tissue regeneration. Inspired by the immunomodulatory role of spermidine, an injectable double network hydrogel functionalized with spermidine (DN-SPD) is developed, where the first and second networks are formed by dynamic imine bonds and non-dynamic photo-crosslinked bonds respectively. The single network hydrogel before photo-crosslinking exhibits excellent injectability and thus can be printed and photo-crosslinked in situ to form double network hydrogels. DN-SPD hydrogel has demonstrated desirable mechanical properties and tissue adhesion. More importantly, an "operando" comparison of hydrogels loaded with spermidine or diethylenetriamine (DETA), a sham molecule resembling spermidine, has shown similar physical properties, but quite different biological functions. Specifically, the outcomes of 3 sets of in vivo animal experiments demonstrate that DN-SPD hydrogel can not only reduce inflammation caused by implanted exogenous biomaterials and reactive oxygen species but also promote the polarization of macrophages toward regenerative M2 phenotype, in comparison with DN-DETA hydrogel. Moreover, the immunoregulation by spermidine can also translate into faster and more natural healing of both acute wounds and diabetic wounds. Hence, the local administration of spermidine affords a simple but elegant approach to attenuate foreign body reactions induced by exogenous biomaterials to treat chronic refractory wounds.

Echinatin attenuates acute lung injury and inflammatory responses via TAK1-MAPK/NF-κB and Keap1-Nrf2-HO-1 signaling pathways in macrophages

Echinatin is an active ingredient in licorice, a traditional Chinese medicine used in the treatment of inflammatory disorders. However, the protective effect and underlying mechanism of echinatin against acute lung injury (ALI) is still unclear. Herein, we aimed to explore echinatin-mediated anti-inflammatory effects on lipopolysaccharide (LPS)-stimulated ALI and its molecular mechanisms in macrophages. In vitro, echinatin markedly decreased the levels of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated murine MH-S alveolar macrophages and RAW264.7 macrophages by suppressing inducible nitric oxide synthase and cyclooxygenase-2 (COX-2) expression. Furthermore, echinatin reduced LPS-induced mRNA expression and release of interleukin-1β (IL-1β) and IL-6 in RAW264.7 cells. Western blotting and CETSA showed that echinatin repressed LPS-induced activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) pathways through targeting transforming growth factor-beta-activated kinase 1 (TAK1). Furthermore, echinatin directly interacted with Kelch-like ECH-associated protein 1 (Keap1) and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway to enhance heme oxygenase-1 (HO-1) expression. In vivo, echinatin ameliorated LPS-induced lung inflammatory injury, and reduced production of IL-1β and IL-6. These findings demonstrated that echinatin exerted anti-inflammatory effects in vitro and in vivo, via blocking the TAK1-MAPK/NF-κB pathway and activating the Keap1-Nrf2-HO-1 pathway.

Spatiotemporal orchestration of macrophage activation trajectories by Vγ4 T cells during skin wound healing

Dysregulated macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes underlies impaired cutaneous wound healing. This study reveals Vγ4+ γδ T cells spatiotemporally calibrate macrophage trajectories during skin repair via sophisticated interferon-γ (IFN-γ) conditioning across multiple interconnected tissues. Locally within wound beds, infiltrating Vγ4+ γδ T cells directly potentiate M1 activation and suppress M2 polarization thereby prolonging local inflammation. In draining lymph nodes, infiltrated Vγ4+ γδ T cells expand populations of IFN-γ-competent lymphocytes which disseminate systemically and infiltrate into wound tissues, further enforcing M1 macrophages programming. Moreover, Vγ4+γδ T cells flushed into bone marrow stimulate increased IFN-γ production, which elevates the output of pro-inflammatory Ly6C+monocytes. Mobilization of these monocytes continually replenishes the M1 macrophage pool in wounds, preventing phenotypic conversion to M2 activation. Thus, multi-axis coordination of macrophage activation trajectories by trafficking Vγ4+ γδ T cells provides a sophisticated immunological mechanism regulating inflammation timing and resolution during skin repair.

Research Progress in Skin Aging and Immunity

Skin aging is a complex process involving structural and functional changes and is characterized by a decrease in collagen content, reduced skin thickness, dryness, and the formation of wrinkles. This process is underpinned by multiple mechanisms including the free radical theory, inflammation theory, photoaging theory, and metabolic theory. The skin immune system, an indispensable part of the body's defense mechanism, comprises macrophages, lymphocytes, dendritic cells, and mast cells. These cells play a pivotal role in maintaining skin homeostasis and responding to injury or infection. As age advances, along with various internal and external environmental stimuli, skin immune cells may undergo senescence or accelerated aging, characterized by reduced cell division capability, increased mortality, changes in gene expression patterns and signaling pathways, and altered immune cell functions. These changes collectively impact the overall function of the immune system. This review summarizes the relationship between skin aging and immunity and explores the characteristics of skin aging, the composition and function of the skin immune system, the aging of immune cells, and the effects of these cells on immune function and skin aging. Immune dysfunction plays a significant role in skin aging, suggesting that immunoregulation may become one of the important strategies for the prevention and treatment of skin aging.

Macrophages in acne vulgaris: mediating phagocytosis, inflammation, scar formation, and therapeutic implications

Macrophages serve as a pivotal nexus in the pathogenesis of acne vulgaris, orchestrating both the elimination of Cutibacterium acnes (C. acnes) and lipid metabolic regulation while also possessing the capacity to exacerbate inflammation and induce cutaneous scarring. Additionally, recent investigations underscore the therapeutic potential inherent in macrophage modulation and challenge current anti-inflammatory strategies for acne vulgaris. This review distills contemporary advances, specifically examining the dual roles of macrophages, underlying regulatory frameworks, and emergent therapeutic avenues. Such nuanced insights hold the promise of guiding future explorations into the molecular etiology of acne and the development of more efficacious treatment modalities.

The Mechanism of Pyroptosis and Its Application Prospect in Diabetic Wound Healing

Pyroptosis defines a form of pro-inflammatory-dependent programmed cell death triggered by gasdermin proteins, which creates cytoplasmic pores and promotes the activation and accumulation of immune cells by releasing several pro-inflammatory mediators and immunogenic substances upon cell rupture. Pyroptosis comprises canonical (mediated by Caspase-1) and non-canonical (mediated by Caspase-4/5/11) molecular signaling pathways. Numerous studies have explored the contributory roles of inflammasome and pyroptosis in the progression of multiple pathological conditions such as tumors, nerve injury, inflammatory diseases and metabolic disorders. Accumulating evidence indicates that the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome results in the activation of pyroptosis and inflammation. Current evidence suggests that pyroptosis-dependent cell death plays a progressive role in the development of diabetic complications including diabetic wound healing (DWH) and diabetic foot ulcers (DFUs). This review presents a brief overview of the molecular mechanisms underlying pyroptosis and addresses the current research on pyroptosis-dependent signaling pathways in the context of DWH. In this review, we also present some prospective therapeutic compounds/agents that can target pyroptotic signaling pathways, which may serve as new strategies for the effective treatment and management of diabetic wounds.