Accelerated wound healing in diabetes by reprogramming the macrophages with particle-induced clustering of the mannose receptors

Cryopreservable, scalable and ready-to-use cell-laden patches for diabetic ulcer treatment

Stem cell-laden hydrogel patches are promising candidates to treat chronic ulcers due to cells' long-lasting and dynamic responses to wound microenvironment. However, their clinical translations are prohibited by the cryopreservation difficulty due to their weak mechanical strength and slow biotransport capability, and by the morphological mismatch between clinical ulcers and pre-fabricated patches. Here we report a stem cell-laden alginate-dopamine hydrogel patch that can be readily cryopreserved, processed, and scaled toward clinical usages. This cell-hydrogel patch not only maintains cell viability and structure integrity during cryopreservation, but also can be directly utilized without centrifugation or incubation post cryopreservation. In addition, this tissue-adhesive hydrogel patch enables close wound contact and fast cellular response, and its scalable and flexible structure enables assembly for large or irregularly shaped ulcers. Therefore, it accelerates ulcer healing and reduces scar formation via continuous, versatile, self-adjusting paracrine of imbedded, cryopreserved stem cells. These findings highlight its potential for scalable clinical applications in chronic wound management and pave the way for broader adoption of ready-to-use regenerative therapies.

Islet transplantation in immunomodulatory nanoparticle-remodeled spleens

Islet transplantation is a promising therapy for insulin-dependent diabetes. However, immune rejection and insufficient vascularization hinder the survival and function of transplanted islets. Here, we show effective engraftment of vascularized and functional mouse and rat islets transplanted into biomaterial-remodeled spleens of nonimmunosuppressed rodents and human islets transplanted into the remodeled spleens of nonhuman primates (NHPs) on varying degrees of immunosuppression. We found evidence that konjac glucomannan-modified silica nanoparticles (KSiNPs) remodeled the spleen into an extracellular matrix (ECM)-rich, immunosuppressive niche to support the survival of syngeneic or xenogeneic islets. Transplanted islets in the remodeled spleens showed improved engraftment, neovascularization, and functionality and restored normoglycemia in streptozotocin (STZ)-induced type 1 diabetic models in the mice and macaques, with stable insulin and C-peptide secretion in mice for 90 days and macaques for 28 days. KSiNP injection and islet transplantation into macaque spleens under B-ultrasound guidance were preclinically feasible. These findings highlight the safety and effectiveness of spleen tissue remodeling in supporting the survival and function of transplanted islets, providing a promising strategy for treating type 1 diabetes mellitus (T1DM).

An antioxidant, antibacterial, and immunoregulatory konjac glucomannan-based nanocomposite hydrogel for promoting skin wound healing

Managing open skin wounds remains a notable challenge in clinical practice, with wound dressings gradually becoming an essential strategy for such treatment. To effectively regulate the wound healing microenvironment, we developed an antibiotic-free nanocomposite hydrogel by combining guanosine-based supramolecular G-quadruplexes (G4), angiogenic deferoxamine (DFO), konjac glucomannan (KGM), and zinc ions through a one-pot mixing strategy. The borate esters in G4 endow the hydrogel with a strong radical-scavenging ability. As a mannose-containing polysaccharide, KGM does not affect the self-assembly of G-quartets and also induces macrophage polarization toward the anti-inflammatory M2 phenotype without requiring expensive exogenous cytokines. Zinc ions were introduced to enhance the hydrogel's mechanical properties by forming coordination interactions with DFO and endowing the hydrogel with excellent antibacterial properties. Collectively, this biocompatible hydrogel accelerates skin wound closure and promotes mature tissue regeneration by stimulating macrophage polarization toward the M2 phenotype, expediting collagen deposition, alleviating inflammation, and enhancing angiogenesis. Overall, this multifunctional hydrogel can serve as a versatile wound dressing material in regenerative medicine.

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 preparation of methacrylated oxidized konjac glucomannan hydrogel system and its treatment for diabetic wounds

The management of diabetic wounds has become an important task for the public health system. Hydrogels are highly anticipated as modern wound dressings for the treatment of diabetic wounds, hence we have prepared a MOK-Gel using methacrylated oxidized konjac glucomannan (MOK) crosslinked with acrylamide (AM). On this basis, we have incorporated drugs such as UiO-66 loaded with sodium ferulate (SF) and deferoxamine (DFO) to develop the hydrogel wound dressing DUS@MOK-Gel (a hydrogel composed of methacrylated oxidized konjac glucomannan, loaded with DFO and UiO-66 loaded with sodium ferulate). It not only has excellent physical properties, including swelling capacity, moisture retention, and water vapor permeability; but also possesses bioactivity functions such as antioxidant, anti-inflammatory, macrophage polarization regulation, promotion of anti-inflammatory factor release, and angiogenesis to accelerate the healing of diabetic wounds. Therefore, DUS@MOK-Gel has great development prospects and market value in the field of diabetic wound treatment.

An injectable and adaptable system for the sustained release of hydrogen sulfide for targeted diabetic wound therapy by improving the microenvironment of inflammation regulation and angiogenesis

The combined effects of persistent chronic inflammation, oxidative stress, microcirculation disorders, and dysregulated cellular energy metabolism often hinder the repair of diabetic skin wounds. Traditional treatment methods are typically insufficient in simultaneously addressing these complex factors, resulting in delayed wound healing and a high propensity for recurrence and chronic ulceration. This study developed an innovative strategy based on reactive oxygen species (ROS)-responsive nanoparticles loaded with an ultraviolet (UV)-light-responsive hydrogen sulfide (H2S) donor. This approach leverages the endogenous ROS present in diabetic wounds and external UV light as dual triggers to facilitate the controlled and stepwise release of H2S. The material design explicitly targets the critical challenges in diabetic wound repair, including the inhibition of chronic inflammation, oxidative stress reduction, microcirculation improvement, and support of cellular energy metabolism, thereby significantly accelerating wound healing. This adaptive release of signaling molecules effectively modulates the wound regeneration microenvironment, enhancing the repair process and offering a promising solution for diabetic skin wound management. STATEMENT OF SIGNIFICANCE: This study developed an innovative strategy based on reactive oxygen species (ROS)-responsive nanoparticles loaded with an ultraviolet (UV)-light-responsive hydrogen sulfide (H2S) donor. This approach leverages the endogenous ROS present in diabetic wounds and external UV light as dual triggers to facilitate the controlled and stepwise release of H2S. The material design explicitly targets the critical challenges in diabetic wound repair, including the inhibition of chronic inflammation, oxidative stress reduction, microcirculation improvement, and support of cellular energy metabolism, thereby significantly accelerating wound healing. This adaptive release of signaling molecules effectively modulates the wound regeneration microenvironment, enhancing the repair process and offering a promising solution for diabetic skin wound management.

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.

Effects of a Bioengineered Allogeneic Cellularized Construct (BACC) on Primary Human Macrophage Phenotype

The mechanisms behind the pro-healing effects of multicellular, bioengineered allogeneic cellularized constructs (BACC) are not known. Macrophages are key regulators of every phase of the wound healing process and the primary cells that mediate the response to biomaterials. It is hypothesized that cells within the BACC modulate macrophage behavior, which may contribute to the mechanism by which BACC promotes healing. To probe the influence of cells within the BACC compared to effects of the underlying collagen substrate, primary human macrophages are cultured in direct or indirect contact with BACC or with the same collagen substrate used in the BACC manufacturing. Macrophage phenotype is characterized over time via multiplex gene expression, protein secretion, multidimensional flow cytometry, and functional assays with fibroblasts and endothelial cells. The BACC causes macrophages to exhibit a predominately reparative phenotype over time compared to relevant collagen substrate controls, with multiple subpopulations expressing both pro-inflammatory and reparative markers. Conditioned media from macrophage-BACC co-cultures causes distinct effects on fibroblast and endothelial cell proliferation, migration, and network formation. Given the critical role of the reparative macrophage phenotype in wound healing, these results suggest that modulation of macrophage phenotype may be a critical part of the mechanisms behind BACC's pro-healing effects.

Tailor-made curdlan based nanofibrous dressings enable diabetic wound healing

The development and application of novel polysaccharides that can improve diabetic wound healing is crucial. Dressings containing curdlan have the potential to promote healing in diabetic wounds, but the underlying mechanism remain unclear. In addition, the functional modifications that could further enhance the activity of curdlan in promoting diabetic wound healing have not been explored. Herein, we investigated the capabilities of curdlan (CU) and its four derivatives i.e., sulfated curdlan (SC), amino-curdlan (AC) carboxymethyl curdlan (CMC) and CMC/ZnO nanocomposites for diabetic wound healing. Pristine CU and its derivatives were blended with polyvinyl alcohol (PVA) to fabricate electrospun nanofiber dressings (ENDs) with uniform appearances. The PVA/CU, PVA/CMC and PVA/CMC-ZnO ENDs were more compatible with keratinocytes, fibroblasts, and macrophages than that of PVA/AC ENDs. Notably, PVA/CMC ENDs and PVA/CMC-ZnO ENDs exhibited superior wound healing efficiencies than other ENDs. Among various dressings, PVA/CU, PVA/SC, PVA/CMC ENDs effectively reduced M1 macrophages and facilitated M2 phenotype at early stage of diabetic wound healing. Collectively, the PVA/CMC ENDs demonstrated greater therapeutic potential against diabetic wounds compared to other modified scaffolds via regulating macrophage polarization.

Self-Assembled Eutectogel with Cell Permeation and Multiple Anti-Inflammatory Abilities for Treating Chronic Periodontitis

Eutectogels represent an attractive option for various industrial applications that use deep eutectic solvents (DESs) as effective liquid active ingredients and offer remarkable stability, cost-effectiveness, and environmental friendliness. However, the biological applications of these compounds are limited. DESs are highly structurally tunable and exhibit remarkable biofunctionality and biocompatibility, conferring substantial benefits in the treatment of diseases. In this study, choline-chloride and mannose are used to fabricate ChCl/M DES, followed by introduction of lysozyme fibers and gallic acid for self-assembly into injectable eutectogels through hydrogen bonding and hydrophilic/hydrophobic interaction interactions. The eutectogels demonstrate almost 100% bactericidal activities against three strains and significant immune-regulation. This is supported by a decrease in the proportion of CD86-expressing cells from 64.02% to 18.17% and an increase in CD206-expressing cells from 2.53% to 29.96% through flow cytometry experiments. The eutectogels effectively inhibit alveolar bone loss and alleviated local inflammation in a rat model of chronic periodontitis owing to the promotion of gallic acid in the cell membrane by the ChCl/M DES. Hence, self-assembled eutectogels exhibit the potential to enhance the efficacy if treatments/therapies against inflammatory diseases by facilitating bacterial control, reactive oxygen species scavenging, and the regulation of macrophages by promoting cell permeation of small-molecule drugs.

Integrating Data Mining with Metabolomics to Analyze the Mechanism of the "Pearl-Borneol" Pair in Promoting Healing of Diabetic Wounds

INTRODUCTION

Chronic diabetic wounds pose a significant threat to the health of diabetic patients, representing severe and enduring complications. Globally, an estimated 2.5% to 15% of the annual health budget is associated to diabetes, with diabetic wounds accounting for a substantial share. Exploring new therapeutic agents and approaches to address delayed and impaired wound healing in diabetes becomes imperative. Traditional Chinese medicine (TCM) has a long history and remarkable efficacy in treating chronic wound healing.

METHODS

In this study, all topically applied Proprietary Chinese Medicines (pCMs) for wound healing officially approved by China National Medical Products Administration (NMPA) were collected from the NMPA TCM database. Data mining was employed to obtain a highfrequency TCM ingredients pair, Pearl-Borneol (1:1). Subsequently, This study investigated the effect and molecular mechanism of the Pearl-Borneol pair on the healing of diabetic wounds by animal experiments and metabolomics.

RESULTS

The animal experiments showed that the Pearl-Borneol pair significantly accelerated diabetic wound healing, exhibiting a more potent effect than the Pearl or Borneol treatment alone. Meanwhile, the metabolomics analysis identified significant differences in metabolic profiles in wounds between the Model and Normal groups, indicating that diabetic wounds had distinct metabolic characteristics from normal wounds. Moreover, Vaseline-treated wounds exhibited similar metabolic profiles to the wounds from the Model group, suggesting that Vaseline might have a negligible impact on diabetic wound metabolism. In addition, wounds treated with Pearl, Borneol, and Pearl-Borneol pair displayed significantly different metabolic profiles from Vaseline-treated wounds, signifying the influence of these treatments on wound metabolism. Subsequent enrichment analysis of the metabolic pathway highlighted the involvement of the arginine metabolic pathway, closely associated with diabetic wounds, in the healing process under Pearl-Borneol pair treatment. Further analysis revealed elevated levels of arginine and citrulline, coupled with reduced nitric oxide (NO) in both the Model and Vaseline-treated wounds compared to normal wounds, pointing to impaired arginine utilization in diabetic wounds. Interestingly, treatment with Pearl and Pearl-Borneol pair lowered arginine and citrulline levels while increasing NO content, suggesting that these treatments may promote the catabolism of arginine to generate NO, thereby facilitating faster wound closure. Additionally, Borneol alone significantly elevated NO content in wounds, potentially due to its ability to directly reduce nitrates/nitrites to NO. Oxidative stress is a defining characteristic of impaired metabolism in diabetic wounds. Our result showed that both Pearl and Pearl-Borneol pair decreased the oxidative stress biomarker methionine sulfoxide level in diabetic wounds compared to those treated with Vaseline, indicating that Pearl alone or combined with Borneol may enhance the oxidative stress microenvironment in diabetic wounds.

CONCLUSION

In summary, the findings validate the effectiveness of the Pearl-Borneol pair in accelerating the healing of diabetic wounds, with effects on reducing oxidative stress, enhancing arginine metabolism, and increasing NO generation, providing a mechanistic basis for this therapeutic approach.

Konjac glucomannan exerts regulatory effects on macrophages and its applications in biomedical engineering

Konjac glucomannan (KGM) molecular chains contain a small amount of acetyl groups and a large number of hydroxyl groups, thereby exhibiting exceptional water retention and gel-forming properties. To meet diverse requirements, KGM undergoes modification processes such as oxidation, acetylation, grafting, and cationization, which reduce its viscosity, enhance its mechanical strength, and improve its water solubility. Researchers have found that KGM and its derivatives can regulate the polarization of macrophages, inducing their transformation into classically activated M1-type macrophages or alternatively activated M2-type macrophages, and even facilitating the interconversion between M1 and M2 phenotypes. Concurrently, the modulation of macrophage polarization states holds significant importance for chronic wound healing, inflammatory bowel disease (IBD), antitumor therapy, tissue engineering scaffolds, oral vaccines, pulmonary delivery, and probiotics. Therefore, KGM has the advantages of both immunomodulatory effects (biological activity) and gel-forming properties (physicochemical properties), giving it significant advantages in a variety of biomedical engineering applications.

Apigenin accelerates wound healing in diabetic mice by promoting macrophage M2-type polarization via increasing miR-21 expression

The alteration of inflammatory phenotype by macrophage polarization plays an important role in diabetic wound repair. Apigenin has been reported to be anti-inflammatory and promote tissue repair; however, whether it regulates macrophage polarization to participate in diabetic wound repair remains to be investigated. We found that apigenin promoted miR-21 expression in LPS-stimulated RAW264.7 cells, inhibited cellular M1-type factor TNF-α and IL-1β secretion and increased M2-type factor IL-10 and TGF-β secretion, and accelerated macrophage conversion from M1 type to M2 type, whereas this protective effect of apigenin was counteracted by a miR-21 inhibitor. Moreover, we established a macrophage-HUVECs cell in vitro co-culture system and found that apigenin accelerated the migration, proliferation, and VEGF secretion of HUVECs by promoting macrophage miR-21 expression. Further, mechanistic studies revealed that this was mediated by the TLR4/Myd88/NF-κB axis. In in vivo study, diabetic mice had significantly delayed wound healing compared to non-diabetic mice, accelerated wound healing in apigenin-treated diabetic mice, and decreased M1-type macrophages and increased M2-type macrophages in wound tissues.

Effects of a bioengineered allogeneic cellular construct on burn-related macrophage phenotype

Bioengineered allogeneic cellularised constructs (BACC) exert pro-healing effects in burn wounds and skew macrophage phenotype towards a predominately reparative phenotype. However, whether BACC can modulate the phenotype of dysregulated macrophages, like those present in burn wounds, is not known. To better understand the macrophage modulatory characteristics of the BACC, primary human macrophages were polarised to the M2b phenotype, an immunosuppressive phenotype relevant to burn wounds, by simultaneously exposing macrophages to polystyrene plate-coated immunoglobulin G and the endotoxin lipopolysaccharide (LPS). The resulting macrophage phenotype upregulated both inflammatory and reparative genes, and increased secretion of the M2b marker CCL1 compared to five different in vitro macrophage phenotypes. M2b macrophages were cultured with the BACC in the presence or absence of LPS to mimic infection, which is a common occurrence in burn wounds. The BACC caused up-regulation of reparative gene sets and down-regulation of pro-inflammatory gene sets, even when LPS was present in the cell culture media. Co-cultures were maintained for 1, 3, or 5 days in the presence of LPS, and by day 1 both non-activated macrophages and M2b macrophages exhibited signs of endotoxin tolerance, as demonstrated by a reduced secretion of tumour necrosis factor α (TNFα) in response to fresh LPS stimulus. The BACC was not able to prevent endotoxin tolerance, but reparative genes were upregulated in macrophages chronically exposed to LPS. These results suggest that the BACC can promote a reparative phenotype in dysregulated macrophages relevant to the pathophysiology of burns.

Biochemical, immunological markers, histology and ultrastructural changes of open wound healing in rats treated with ethyl acetate extract of Zingiber zerumbet rhizomes

Research on plant-based wound healing agents has been one of the current developing areas in modern biomedical science. This study aimed to assess the effects of ethyl acetate extract of Zingiber zerumbet rhizome (ZZRE) on open wound healing activity in Wistar rats. Ninety male Wistar rats (220-320 g) were divided into three groups treated with phosphate buffered saline (PBS) (negative control), Solcoseryl gel (positive control), and 10 % ZZRE (treatment group), respectively. Six circular full-skin thickness wounds of 6.0 mm in diameter were induced bilaterally on the dorsal surface of each rat. Six rats were sacrificed on Day-1, Day-3, Day-6, Day-10 and Day-14 respectively from each group after wound induction. All data obtained are considered statistically significant at p < 0.05. Macroscopic observations showed that the 10 % ZZRE treated wounds healed faster compared to other groups. The wound closure percentage showed that the wound treated with 10 % ZZRE is significantly higher (p < 0.05) than the PBS group on Day-6, Day-10 and Day-14. Protein levels of the 10 % ZZRE group decreased significantly at Day-1 compared to the PBS group and significantly (p < 0.05) higher at Day-14 compared to both control groups. The hexosamine and uronic acid levels of the 10 % ZZRE group showed a significant (p < 0.05) decrease on Day-14. Conversely, hydroxyproline levels showed significant (p < 0.05) increase starting from Day-3 until Day-14. As for the immunological markers, the level of total TGF-β1 of the 10 % ZZRE group was significantly (p < 0.05) higher than the PBS group on Day-14, whereas the level of IL-10 on the wound tissue of the 10 % ZZRE group was significantly (p < 0.05) lower than the PBS group on Day-1 but significantly (p < 0.05) higher on Day-10 and Day-14 compared to both control groups. Histological observation showed that the wounds treated with 10 % ZZRE infiltrated with lesser inflammatory cells while collagen deposition was denser as compared to both control groups. Based on the result obtained, it is clearly proven that treatment of 10 % ZZRE on open wound healing in rats, showed that the extract was effective in healing the wound and accelerated the healing process. Therefore, the 10 % ZZRE tested has the potential to be developed as an alternative wound healing agent in the future.

Mannose coated selenium nanoparticles normalize intestinal homeostasis in mice and mitigate colitis by inhibiting NF-κB activation and enhancing glutathione peroxidase expression

Impaired intestinal homeostasis is a major pathological feature of inflammatory bowel diseases (IBD). Mannose and selenium (Se) both demonstrate potential anti-inflammatory and anti-oxidative properties. However, most lectin receptors bind free monosaccharide ligands with relatively low affinity and most Se species induce side effects beyond a very narrow range of dosage. This has contributed to a poorly explored therapies for IBD that combine mannose and Se to target intestinal epithelial cells (IECs) for normalization gut homeostasis. Herein, a facile and safe strategy for ulcerative colitis (UC) treatment was developed using optimized, mannose-functionalized Se nanoparticles (M-SeNPs) encapsulated within a colon-targeted hydrogel delivery system containing alginate (SA) and chitosan (CS). This biocompatible nanosystem was efficiently taken up by IECs and led to increased expression of Se-dependent glutathione peroxidases (GPXs), thereby modulating IECs' immune response. Using a mouse model of DSS-induced colitis, (CS/SA)-embedding M-SeNPs (C/S-MSe) were found to mitigate oxidative stress and inflammation through the inhibition of the NF-kB pathway in the colon. This stabilized mucosal homeostasis of IECs and ameliorated colitis-related symptoms, thereby providing a potential new approach for treatment of IBD.

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.

Antioxidant and Immunomodulatory Polymer Vesicles for Effective Diabetic Wound Treatment through ROS Scavenging and Immune Modulating

Chronic diabetic wound patients usually show high glucose levels and systemic immune disorder, resulting in high reactive oxygen species (ROS) levels and immune cell dysfunction, prolonged inflammation, and delayed wound healing. Herein, we prepared an antioxidant and immunomodulatory polymer vesicle for diabetic wound treatment. This vesicle is self-assembled from poly(ε-caprolactone)36-block-poly[lysine4-stat-(lysine-mannose)22-stat-tyrosine)16] ([PCL36-b-P[Lys4-stat-(Lys-Man)22-stat-Tyr16]). Polytyrosine is an antioxidant polypeptide that can scavenge ROS. d-Mannose was introduced to afford immunomodulatory functions by promoting macrophage transformation and Treg cell activation through inhibitory cytokines. The mice treated with polymer vesicles showed 23.7% higher Treg cell levels and a 91.3% higher M2/M1 ratio than those treated with PBS. Animal tests confirmed this vesicle accelerated healing and achieved complete healing of S. aureus-infected diabetic wounds within 8 days. Overall, this is the first antioxidant and immunomodulatory vesicle for diabetic wound healing by scavenging ROS and regulating immune homeostasis, opening new avenues for effective diabetic wound healing.

Biomimetic and Wound Microenvironment-Modulating PEGylated Glycopolypeptide Hydrogels for Arterial Massive Hemorrhage and Wound Prohealing

Despite great progress in the hydrogel hemostats and dressings, they generally lack resistant vascular bursting pressure and intrinsic bioactivity to meet arterial massive hemorrhage and proheal wounds. To address the problems, we design a kind of biomimetic and wound microenvironment-modulating PEGylated glycopolypeptide hydrogels that can be easily injected and gelled in ∼10 s. Those glycopolypeptide hydrogels have suitable tissue adhesion of ∼20 kPa, high resistant bursting pressure of ∼150 mmHg, large microporosity of ∼15 μm, and excellent biocompatibility with ∼1% hemolysis ratio and negligible inflammation. They performed better hemostasis in rat liver and rat and rabbit femoral artery bleeding models than Fibrin glue, Gauze, and other hydrogels, achieving fast arterial hemostasis of <20 s and lower blood loss of 5-13%. As confirmed by in vivo wound healing, immunofluorescent imaging, and immunohistochemical and histological analyses, the mannose-modified hydrogels could highly boost the polarization of anti-inflammatory M2 phenotype and downregulate pro-inflammatory tumor necrosis factor-α to relieve inflammation, achieving complete full-thickness healing with thick dermis, dense hair follicles, and 90% collagen deposition. Importantly, this study provides a versatile strategy to construct biomimetic glycopolypeptide hydrogels that can not only resist vascular bursting pressure for arterial massive hemorrhage but also modulate inflammatory microenvironment for wound prohealing.

Modulating the immune system towards a functional chronic wound healing: A biomaterials and Nanomedicine perspective

Chronic non-healing wounds persist as a substantial burden for healthcare systems, influenced by factors such as aging, diabetes, and obesity. In contrast to the traditionally pro-regenerative emphasis of therapies, the recognition of the immune system integral role in wound healing has significantly grown, instigating an approach shift towards immunological processes. Thus, this review explores the wound healing process, highlighting the engagement of the immune system, and delving into the behaviors of innate and adaptive immune cells in chronic wound scenarios. Moreover, the article investigates biomaterial-based strategies for the modulation of the immune system, elucidating how the adjustment of their physicochemical properties or their synergistic combination with other agents such as drugs, proteins or mesenchymal stromal cells can effectively modulate the behaviors of different immune cells. Finally this review explores various strategies based on synthetic and biological nanostructures, including extracellular vesicles, to finely tune the immune system as natural immunomodulators or therapeutic nanocarriers with promising biophysical properties.

Hybrid Hydrogels for Immunoregulation and Proangiogenesis through Mild Heat Stimulation to Accelerate Whole-Process Diabetic Wound Healing

Intense and persistent oxidative stress, excessive inflammation, and impaired angiogenesis severely hinder diabetic wound healing. Bioactive hydrogel dressings with immunoregulatory and proangiogenic properties have great promise in treating diabetic wounds. However, the therapeutic effects of dressings always depend on drugs with side effects, expensive cytokines, and cell therapies. Herein, a novel dynamic borate-bonds crosslinked hybrid multifunctional hydrogel dressings with photothermal properties are developed to regulate the microenvironment of diabetic wound sites and accelerate the whole process of its healing without additional medication. The hydrogel is composed of phenylboronic acid-modified chitosan and hyaluronic acid (HA) crosslinked by tannic acid (TA) through borate bonds and Prussian blue nanoparticles (PBNPs) with photothermal response characteristics are embedded in the polymer networks. The results indicate hydrogels show inherent broad-spectrum antioxidative activities through the integrated interaction of borate bonds, TA, and PBNPs. Meanwhile, combined with the regulation of macrophage phenotype by HA, the inflammatory microenvironment of diabetic wounds is transformed. Moreover, the angiogenesis is then enhanced by the mild photothermal effect of PBNPs, followed by promoted epithelialization and collagen deposition. In summary, this hybrid hydrogel system accelerates all stages of wound repair through antioxidative stress, immunomodulation, and proangiogenesis, showing great potential applications in diabetic wound management.

Combined therapeutic strategy based on blocking the deleterious effects of AGEs for accelerating diabetic wound healing

Diabetic foot ulcer is a serious complication of diabetes. Excessive accumulation of advanced glycation end products (AGEs) is one of the critical pathogenic factors in postponing diabetic wound healing. The main pathogenic mechanisms of AGEs include inducing cellular dysfunction, prolonging inflammatory response, increasing oxidative stress and reducing endogenous nitric oxide (NO) production. Combination therapy of blocking the deleterious effects of AGEs and supplementing exogenous NO is hypothesized to promote diabetic wound healing. Here, we presented nanoparticles/hydrogel composite dressings to co-delivery rosiglitazone and S-nitroso glutathione into the wound bed. The designed co-delivery system augmented the survival of fibroblasts, reduced oxidative stress levels, reversed the change of mitochondrial membrane potential and decreased the proinflammatory cytokine expression. Local sustained release of therapeutic agents significantly improved the wound healing of diabetic rats including increasing the wound closure rate, alleviating inflammation, promoting collagen fiber production and angiogenesis. Our finding indicated this local deliver strategy aimed at inhibiting the toxic effects of AGEs has great clinical potential for diabetic wound treatment.

Translational Challenges in Drug Therapy and Delivery Systems for Treating Chronic Lower Extremity Wounds

Despite several promising preclinical studies performed over the past two decades, there remains a paucity of market-approved drugs to treat chronic lower extremity wounds in humans. This translational gap challenges our understanding of human chronic lower extremity wounds and the design of wound treatments. Current targeted drug treatments and delivery systems for lower extremity wounds rely heavily on preclinical animal models meant to mimic human chronic wounds. However, there are several key differences between animal preclinical wound models and the human chronic wound microenvironment, which can impact the design of targeted drug treatments and delivery systems. To explore these differences, this review delves into recent new drug technologies and delivery systems designed to address the chronic wound microenvironment. It also highlights preclinical models used to test drug treatments specific for the wound microenvironments of lower extremity diabetic, venous, ischemic, and burn wounds. We further discuss key differences between preclinical wound models and human chronic wounds that may impact successful translational drug treatment design.

Human Fibroblast-Derived Matrix Hydrogel Accelerates Regenerative Wound Remodeling Through the Interactions with Macrophages

Herein, a novel extracellular matrix (ECM) hydrogel is proposed fabricated solely from decellularized, human fibroblast-derived matrix (FDM) toward advanced wound healing. This FDM-gel is physically very stable and viscoelastic, while preserving the natural ECM diversity and various bioactive factors. Subcutaneously transplanted FDM-gel provided a permissive environment for innate immune cells infiltration. Compared to collagen hydrogel, excellent wound healing indications of FDM-gel treated in the full-thickness wounds are noticed, particularly hair follicle formation via highly upregulated β-catenin. Sequential analysis of the regenerated wound tissues disclosed that FDM-gel significantly alleviated pro-inflammatory cytokine and promoted M2-like macrophages, along with significantly elevated vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) level. A mechanistic study demonstrated that macrophages-FDM interactions through cell surface integrins α5β1 and α1β1 resulted in significant production of VEGF and bFGF, increased Akt phosphorylation, and upregulated matrix metalloproteinase-9 activity. Interestingly, blocking such interactions using specific inhibitors (ATN161 for α5β1 and obtustatin for α1β1) negatively affected those pro-healing growth factors secretion. Macrophages depletion animal model significantly attenuated the healing effect of FDM-gel. This study demonstrates that the FDM-gel is an excellent immunomodulatory material that is permissive for host cells infiltration, resorbable with time, and interactive with macrophages, where it thus enables regenerative matrix remodeling toward a complete wound healing.

Floating electrode-dielectric barrier discharge-based plasma promotes skin regeneration in a full-thickness skin defect mouse model

Wound healing involves a complex and dynamic interplay among various cell types, cytokines, and growth factors. Macrophages and transforming growth factor-β1 (TGF-β1) play an essential role in different phases of wound healing. Cold atmospheric plasma has a wide range of applications in the treatment of chronic wounds. Hence, we aimed to investigate the safety and efficacy of a custom-made plasma device in a full-thickness skin defect mouse model. Here, we investigated the wound tissue on days 6 and 12 using histology, qPCR, and western blotting. During the inflammation phase of wound repair, macrophages play an important role in the onset and resolution of inflammation, showing decreased F4/80 on day 6 of plasma treatment and increased TGF-β1 levels. The plasma-treated group showed better epidermal epithelialization, dermal fibrosis, collagen maturation, and reduced inflammation than the control group. Our findings revealed that floating electrode-dielectric barrier discharge (FE-DBD)-based atmospheric-pressure plasma promoted significantly faster wound healing in the plasma-treated group than that in the control group with untreated wounds. Hence, plasma treatment accelerated wound healing processes without noticeable side effects and suppressed pro-inflammatory genes, suggesting that FE-DBD-based plasma could be a potential therapeutic option for treating various wounds.

Biomaterials for immunomodulation in wound healing

The substantial economic impact of non-healing wounds, scarring, and burns stemming from skin injuries is evident, resulting in a financial burden on both patients and the healthcare system. This review paper provides an overview of the skin's vital role in guarding against various environmental challenges as the body's largest protective organ and associated developments in biomaterials for wound healing. We first introduce the composition of skin tissue and the intricate processes of wound healing, with special attention to the crucial role of immunomodulation in both acute and chronic wounds. This highlights how the imbalance in the immune response, particularly in chronic wounds associated with underlying health conditions such as diabetes and immunosuppression, hinders normal healing stages. Then, this review distinguishes between traditional wound-healing strategies that create an optimal microenvironment and recent peptide-based biomaterials that modulate cellular processes and immune responses to facilitate wound closure. Additionally, we highlight the importance of considering the stages of wounds in the healing process. By integrating advanced materials engineering with an in-depth understanding of wound biology, this approach holds promise for reshaping the field of wound management and ultimately offering improved outcomes for patients with acute and chronic wounds.

Photobiomodulation preconditioned diabetic adipose derived stem cells with additional photobiomodulation: an additive approach for enhanced wound healing in diabetic rats with a delayed healing wound

In this preclinical investigation, we examined the effects of combining preconditioned diabetic adipose-derived mesenchymal stem cells (AD-MSCs) and photobiomodulation (PBM) on a model of infected ischemic delayed healing wound (injury), (IIDHWM) in rats with type I diabetes (TIDM). During the stages of wound healing, we examined multiple elements such as stereology, macrophage polarization, and the mRNA expression levels of stromal cell-derived factor (SDF)-1α, vascular endothelial growth factor (VEGF), hypoxia-induced factor 1α (HIF-1α), and basic fibroblast growth factor (bFGF) to evaluate proliferation and inflammation. The rats were grouped into: (1) control group; (2) diabetic-stem cells were transversed into the injury site; (3) diabetic-stem cells were transversed into the injury site then the injury site exposed to PBM; (4) diabetic stem cells were preconditioned with PBM and implanted into the wound; (5) diabetic stem cells were preconditioned with PBM and transferred into the injury site, then the injury site exposed additional PBM. While on both days 4, and 8, there were advanced histological consequences in groups 2-5 than in group 1, we found better results in groups 3-5 than in group 2 (p < 0.05). M1 macrophages in groups 2-5 were lower than in group 1, while groups 3-5 were reduced than in group 2 (p < 0.01). M2 macrophages in groups 2-5 were greater than in group 1, and groups 3-5 were greater than in group 2. (p ≤ 0.001). Groups 2-5 revealed greater expression levels of bFGF, VEGF, SDF- 1α, and HIF- 1α genes than in group 1 (p < 0.001). Overall group 5 had the best results for histology (p < 0.05), and macrophage polarization (p < 0.001). AD-MSC, PBM, and AD-MSC + PBM treatments all enhanced the proliferative stage of injury repairing in the IIDHWM in TIDM rats. While AD-MSC + PBM was well than the single use of AD-MSC or PBM, the best results were achieved with PBM preconditioned AD-MSC, plus additional PBM of the injury.

A Biomimetic Se-nHA/PC Composite Microsphere with Synergistic Immunomodulatory and Osteogenic Ability to Activate Bone Regeneration in Periodontitis

Accumulation of reactive oxygen species (ROS) in periodontitis exacerbates the destruction of alveolar bone. Therefore, scavenging ROS to reshape the periodontal microenvironment, alleviate the inflammatory response and promote endogenous stem cell osteogenic differentiation may be an effective strategy for treating bone resorption in periodontitis. In this study, sericin-hydroxyapatite nanoparticles (Se-nHA NPs) are synthesized using a biomimetic mineralization method. Se-nHA NPs and proanthocyanidins (PC) are then encapsulated in sericin/sodium alginate (Se/SA) using an electrostatic injection technique to prepare Se-nHA/PC microspheres. Microspheres are effective in scavenging ROS, inhibiting the polarization of macrophages toward the M1 type, and inducing the polarization of macrophages toward the M2 type. In normal or macrophage-conditioned media, the Se-nHA/PC microspheres effectively promoted the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). Furthermore, the Se-nHA/PC microspheres demonstrated anti-inflammatory effects in a periodontitis rat model by scavenging ROS and suppressing pro-inflammatory cytokines. The Se-nHA/PC microspheres are also distinguished by their capacity to decrease alveolar bone loss, reduce osteoclast activity, and boost osteogenic factor expression. Therefore, the biomimetic Se-nHA/PC composite microspheres have efficient ROS-scavenging, anti-inflammatory, and osteogenic abilities and can be used as a multifunctional filling material for inflammatory periodontal tissue regeneration.

Suppression of SOCS3 expression in macrophage cells: Potential application in diabetic wound healing

Impaired polarization of M1 to M2 macrophages has been reported in diabetic wounds. We aimed to improve this polarization by down-regulation of expression of the "Suppressor of Cytokine Signaling 3" (SOCS3) gene in macrophages. Two oligodeoxynucleotide (ASO) sequences were designed against SOC3 mRNA and were loaded to mannosylated-polyethyleneimine (Man-PEI). The optimum N/P ratio for Man-PEI-ASO was determined to be 8 based on loading efficiency, particle size, zeta potential, cellular uptake and cytotoxicity assay. pH stability of ASO in Man-PEI-ASO and its protection from DNase I was confirmed. After in vitro treatment of macrophages with Man-PEI-ASO, SOCS3 was downregulated, SOCS1 upregulated, and SOCS1/SOCS3 ratio increased. Also, expressions of macrophage markers of M2 (IL-10, Arg1, CD206) increased and those of M1 (IL-1β, NOS2, CD68) decreased, and secretion of pro-inflammatory cytokines (TNF-α and IL-1β) decreased while that of anti-inflammatory cytokine IL-4 increased. All suggested a polarization into M2 phenotype. Finally, the Man-PEI-ASO was loaded in hydrogel and applied to a diabetic wound model in mice. It improved the healing to the level observed in non-diabetic wounds. We show that using antisense sequences against SOC3 mRNA, macrophage polarization could be directed into the M2 phenotype and healing of diabetic wound could be highly improved.

Unmasking Chemokine-Inducing Specificity in Oligosaccharide Biomaterial to Promote Hair Growth

Hair loss affects over 50 million people worldwide with limited therapeutic options. Despite evidence highlighting the vital role of local immune cells in regulating the life cycle of hair follicles (HFs), accurate regulation of immunocytes to directly promote hair growth remains unachieved. Here, inspired by the physiological feedback in the skin immunity to suppress microbe-triggered inflammation, an oligosaccharide biomaterial with "unmasked" specific activity is developed to recruit regulatory T (Treg ) cells around HFs, leading to accelerated hair growth in mice. By processing the glucomannan polysaccharide via controllable enzymatic cleavage, a series of oligosaccharide fractions with more specific chemokine-inducing functions is obtained. Notably, a hexasaccharide-based fraction (OG6) stimulates macrophages to selectively express Treg -chemoattractant C-C Motif Chemokine Ligand 5 (CCL5) through a mannose receptor-mediated endocytosis and NOD1/2-dependent signaling, as evidenced by molecular docking, inhibition assays, and a Foxp3-reporter mouse model. Intradermal delivery of OG6 to the depilated mouse skin promotes Treg mobilization around HFs and stimulates de novo regeneration of robust hairs. This study demonstrates that unmasking precise immunomodulatory functions in oligosaccharides from their parental polysaccharide can potentially solve the long-lasting dilemma with polysaccharide biomaterials that are widely renowned for versatile activities yet high heterogeneity, opening new avenues to designing glycan-based therapeutic tools with improved specificity and safety.

Genome-wide screening of m6A profiling of cutaneous wound healing in diabetic mice

OBJECTIVE

Impaired wound healing in diabetes mellitus (DM) is a major health burden on patients, their families, and society. The present study aimed to systematically profile the m6A modification landscape in cutaneous wounds in a diabetic mouse model.

APPROACH

Diabetes was induced in mice through a single intraperitoneal injection of streptozotocin (STZ); a single intraperitoneal injection of PBS was made in control mice for comparisons. Both groups then received an 8-mm diameter, full-thickness dorsal body wound with a biopsy punch. Five days after wound surgery, western blot analysis of harvested wound tissues from both groups was used to assess the expression of m6A-related enzymes. Genome-wide profiling of m6A-tagged transcripts was performed through MeRIP-seq and RNA-seq.

RESULTS

ALKBH5, an m6A eraser, was significantly upregulated, while METTL3, METTL14, and WTAP, m6A writers, were markedly downregulated in the diabetic wounds. Additionally, a total of 1335 m6A peaks were differentially expressed in MeRIP-seq and RNA-seq analyses, with 558 upregulated and 777 downregulated peaks. Finally, there was hypomethylated and hypermethylated differentiation at the gene and transcript levels.

INNOVATION

The present study was the first to reveal the m6A landscape in diabetic wounds in an animal model.

CONCLUSION

This study, by deeply analyzing the role of m6A modifications in diabetic wound healing, provides new insights and understanding into the molecular mechanisms of diabetic wound healing. Future research could further explore how m6A modifications regulate the wound healing process, thereby offering new potential targets for the treatment of diabetic wounds.

Harnessing cytokine-induced killer cells to accelerate diabetic wound healing: an approach to regulating post-traumatic inflammation

Impaired immunohomeostasis in diabetic wounds prolongs inflammation and cytokine dysfunction, thus, delaying or preventing wound-surface healing. Extensive clinical studies have been conducted on cytokine-induced killer (CIK) cells recently, as they can be easily proliferated using a straightforward, inexpensive protocol. Therefore, the function of CIK cells in regulating inflammatory environments has been drawing attention for clinical management. Throughout the current investigation, we discovered the regenerative capacity of these cells in the challenging environment of wounds that heal poorly due to diabetes. We demonstrated that the intravenous injection of CIK cells can re-establish a proregenerative inflammatory microenvironment, promote vascularization and, ultimately, accelerate skin healing in diabetic mice. The results indicated that CIK cell treatment affects macrophage polarization and restores the function of regenerative cells under hyperglycemic conditions. This novel cellular therapy offers a promising intervention for clinical applications through specific inflammatory regulation functions.

CCL3 Promotes Cutaneous Wound Healing Through Recruiting Macrophages in Mice

Wound healing is a complex process, which involves three stages: inflammation, proliferation, and remodeling. Inflammation is the first step; thus, immune factors play an important regulatory role in wound healing. In this study, we focused on a chemokine, C-C motif chemokine ligand 3 (CCL3), which is often upregulated for expression during wound healing. We compared cutaneous wound healing at the histological, morphological, and molecular levels in the presence and absence of CCL3. The results showed that the wound healing rate in the wild-type and CCL3-/- + CCL3 mice was faster than that of CCL3-/- mice (P < 0.01), and application of CCL3 to wounds increased the healing rate. In the process of wound healing, the degree of reepithelialization and the rate of collagen deposition in the wound of CCL3-/- mice were significantly lower than those of wild-type mice (P < 0.01). The number of macrophages and the expression levels of tumor necrosis factor(TNF)-α and transforming growth factor (TGF)-β1 in the wounds of wild-type mice were much higher than those of the CCL3-/- mice. Removal of macrophages and CCL3-/- mice share similar phenotypes. Therefore, we infer that the wound healing requires the participation of macrophages, and CCL3 may play an important regulatory role through recruiting macrophages to the wound sites.

Supramolecular Integration of Multifunctional Nanomaterial by Mannose-Decorated Azocalixarene with Ginsenoside Rb1 for Synergistic Therapy of Rheumatoid Arthritis

The complexity and progressive nature of diseases require the exploitation of multifunctional materials. However, introducing a function inevitably increases the complexity of materials, which complicates preparation and decreases reproducibility. Herein, we report a supramolecular integration of multifunctional nanomaterials based on mannose-modified azocalix[4]arene (ManAC4A) and ginsenoside Rb1 (Rb1), which showed advances of simplicity and reproducibility. ManAC4A possesses reactive oxygen species (ROS) scavenging capacity and hypoxia-responsiveness, together with macrophage-targeting and induction functionality. Collectively, the Rb1@ManAC4A assembly simply prepared by two components is integrated with multifunction, including triple targeting (ELVIS targeting, macrophage-targeting, and hypoxia-targeted release) and triple therapy (ROS scavenging, macrophage polarization, and the anti-inflammatory effect of Rb1). The spontaneous assembly and recognition of ManAC4A, with its precise structure and molecular weight, facilitated the simple and straightforward preparation of Rb1@ManAC4A, leading to excellent batch consistency. Progress in simplicity and reproducibility, as directed by this research, will catalyze the clinical translation of multifunctional materials.

Platelet Rich Plasma Loaded Multifunctional Hydrogel Accelerates Diabetic Wound Healing via Regulating the Continuously Abnormal Microenvironments

Continuous oxidative stress and cellular dysfunction caused by hyperglycemia are distinguishing features of diabetic wounds. It has been a great challenge to develop a smart dressing that can accelerate diabetic wound healing through regulating abnormal microenvironments. In this study, a platelet rich plasma (PRP) loaded multifunctional hydrogel with reactive oxygen species (ROS) and glucose dual-responsive property is reported. It can be conveniently prepared with PRP, dopamine (DA) grafted alginate (Alg-DA), and 6-aminobenzo[c][1,2]oxaborol-1(3H)-ol (ABO) conjugated hyaluronic acid (HA-ABO) through ionic crosslinks, hydrogen-bond interactions, and boronate ester bonds. The hydrogel possesses injectability, moldability, tissue adhesion, self-healing, low hemolysis, and hemostasis performances. Its excellent antioxidant property can create a low oxidative stress microenvironment for other biological events. Under an oxidative stress and/or hyperglycemia state, the hydrogel can degrade at an accelerated rate to release a variety of cytokines derived from activated blood platelets. The result is a series of positive changes that are favorable for diabetic wound healing, including fast anti-inflammation, activated macrophage polarization toward M2 phenotype, promoted migration and proliferation of fibroblasts, as well as expedited angiogenesis. This work provides an efficient strategy for chronic diabetic wound management and offers an alternative for developing a new-type PRP-based bioactive wound dressing.

The physiological phenomenon and regulation of macrophage polarization in diabetic wound

Macrophages play a crucial role in regulating wound healing, as they undergo a transition from the proinflammatory M1 phenotype to the proliferative M2 phenotype, ultimately contributing to a favorable outcome. However, in hyperglycemic and hyper-reactive oxygen species environments, the polarization of macrophages becomes dysregulated, hindering the transition from the inflammatory to proliferative phase and consequently delaying the wound healing process. Consequently, regulating macrophage polarization is often regarded as a potential target for the treatment of diabetic wounds. The role of macrophages in wound healing and the changes in macrophages in diabetic conditions were discussed in this review. After that, we provide a discussion of recent therapeutic strategies for diabetic wounds that utilize macrophage polarization. Furthermore, this review also provides a comprehensive summary of the efficacious treatment strategies aimed at enhancing diabetic wound healing through the regulation of macrophage polarization. By encompassing a thorough understanding of the fundamental principles and their practical implementation, the advancement of treatment strategies for diabetic wounds can be further facilitated.

Reactive Oxygen Species-Scavenging Nanosystems in the Treatment of Diabetic Wounds

Diabetic wounds are characterized by drug-resistant bacterial infections, biofilm formation, impaired angiogenesis and perfusion, and oxidative damage to the microenvironment. Given their complex nature, diabetic wounds remain a major challenge in clinical practice. Reactive oxygen species (ROS), which have been shown to trigger hyperinflammation and excessive cellular apoptosis, play a pivotal role in the pathogenesis of diabetic wounds. ROS-scavenging nanosystems have recently emerged as smart and multifunctional nanomedicines with broad synergistic applicability. The documented anti-inflammatory and pro-angiogenic ability of ROS-scavenging treatments predestines these nanosystems as promising options for the treatment of diabetic wounds. Yet, in this context, the therapeutic applicability and efficacy of ROS-scavenging nanosystems remain to be elucidated. Herein, the role of ROS in diabetic wounds is deciphered, and the properties and strengths of nanosystems with ROS-scavenging capacity for the treatment of diabetic wounds are summarized. In addition, the current challenges of such nanosystems and their potential future directions are discussed through a clinical-translational lens.

Extracellular Matrix-Mimetic Immunomodulatory Hydrogel for Accelerating Wound Healing

Macrophages play a crucial role in the complete processes of tissue repair and regeneration, and the activation of M2 polarization is an effective approach to provide a pro-regenerative immune microenvironment. Natural extracellular matrix (ECM) has the capability to modulate macrophage activities via its molecular, physical, and mechanical properties. Inspired by this, an ECM-mimetic hydrogel strategy to modulate macrophages via its dynamic structural characteristics and bioactive cell adhesion sites is proposed. The LZM-SC/SS hydrogel is in situ formed through the amidation reaction between lysozyme (LZM), 4-arm-PEG-SC, and 4-arm-PEG-SS, where LZM provides DGR tripeptide for cell adhesion, 4-arm-PEG-SS provides succinyl ester for dynamic hydrolysis, and 4-arm-PEG-SC balances the stability and dynamics of the network. In vitro and subcutaneous tests indicate the dynamic structural evolution and cell adhesion capacity promotes macrophage movement and M2 polarization synergistically. Comprehensive bioinformatic analysis further confirms the immunomodulatory ability, and reveals a significant correlation between M2 polarization and cell adhesion. A full-thickness wound model is employed to validate the induced M2 polarization, vessel development, and accelerated healing by LZM-SC/SS. This study represents a pioneering exploration of macrophage modulation by biomaterials' structures and components rather than drug or cytokines and provides new strategies to promote tissue repair and regeneration.

Sanguisorba officinalis L. promotes diabetic wound healing in rats through inflammation response mediated by macrophage

Sanguisorba officinalis L., a traditional Chinese medicine, is frequently used to treat burns and scalds. But even so, it is unknown whether S. officinalis L. can accelerate diabetic wounds (DW) healing. Here, to bridge the gap, we employed in vivo and in vitro evaluations to assess the positive effect of S. officinalis L. ethanol extract (ESO) on DW. Results demonstrated that ESO dramatically improved the DW healing rate. With ESO treatment, the inappropriately elevated levels of IL6, IL1β and TNFα in DW were reduced, while the expression of IL10 was increased, indicating that the abnormal inflammation in DW was also under control. Moreover, the abnormally elevated expression of CD86 was significantly inhibited and the expression of CD206 was significantly up-regulated following treatment with ESO. The global level of NF-κB protein was not affected by ESO treatment, but it suppressed the expression of phosphorylated NF-κB and prevented its nuclear entry. In addition, in RAW264.7 cells activated with lipopolysaccharide (LPS), the expression of NLRP3, Caspase1 and IL1β were significantly diminished following ESO treatment. In conclusion, ESO was proved to be a promising treatment for DW healing due to its potential to accelerate the healing process by suppressing the inflammatory response. This was achieved by increasing the ratio of M2 to M1 polarization through blocking the NF-κB/NLRP3 signaling pathway.

Nerve Defect Treatment with a Capping Hydroxyethyl Cellulose/Soy Protein Isolate Sponge Conduit for Painful Neuroma Prevention

Painful neuroma, as one of the complications of nerve injury from disease or trauma, results in instinctive neuropathic pain that adversely affects a patient's quality of life. To intercept neuroma development, capping strategies have been performed as effective therapies. Nonetheless, the most appropriate biocompatible material to shield the nerves is an urgent clinical requirement. Herein, a compatible hydroxyethyl cellulose (HEC)/soy protein isolate (SPI) sponge capping conduit (HSSC) is used to prevent neuroma in vivo. Following capping on the sciatic nerve stump in vivo, the behavior of the rats and the structure of tissues are compared through histological assessment and autotomy scoring. The HSSCs gained a dismal autotomy score and enhanced the amelioration, where inflammatory invasions and overdeposition of collagen are defeated. The expression of myelin growth linked genes (Krox20, MPZ, and MAG) in the HSSC group at the eighth week was almost 2 times higher than that of the no capping group. The HSSC conduit served as a physical barrier to repress the infiltration of inflammation as well as provided an optimum microenvironment for facilitating nerve rejuvenation and intercepting neuroma development during nerve amelioration.

Nano drug delivery systems: a promising approach to scar prevention and treatment

Scar formation is a common physiological process that occurs after injury, but in some cases, pathological scars can develop, leading to serious physiological and psychological effects. Unfortunately, there are currently no effective means to intervene in scar formation, and the structural features of scars and their unclear mechanisms make prevention and treatment even more challenging. However, the emergence of nanotechnology in drug delivery systems offers a promising avenue for the prevention and treatment of scars. Nanomaterials possess unique properties that make them well suited for addressing issues related to transdermal drug delivery, drug solubility, and controlled release. Herein, we summarize the recent progress made in the use of nanotechnology for the prevention and treatment of scars. We examine the mechanisms involved and the advantages offered by various types of nanomaterials. We also highlight the outstanding challenges and questions that need to be addressed to maximize the potential of nanotechnology in scar intervention. Overall, with further development, nanotechnology could significantly improve the prevention and treatment of pathological scars, providing a brighter outlook for those affected by this condition.

A tetramethylpyrazine-loaded hyaluronic acid-based hydrogel modulates macrophage polarization for promoting wound recovery in diabetic mice

The failure of wound healing often causes lower limb disability and amputation of diabetic patients. Current strategies for diabetic wound management often fail to achieve the expected outcomes, and emerging alternatives are urgently needed. Recent advances in the identification of active compounds from traditional herbal medicines provide promising therapeutics for tissue repair and regeneration. In this study, the pro-healing effects of tetramethylpyrazine (TMP, a natural alkaloid found in Ligusticum chuanxiong Hort) for diabetic wounds were for the first time demonstrated. The cutaneous healing was mainly achieved by TMP-mediated macrophage polarization from pro-inflammatory to pro-healing phenotype. In addition, the topical administration of TMP was facilitated by the hyaluronic acid (HA) hydrogel for promoting the full-thickness wounds in the experimental diabetic mice. Consequently, TMP-loaded HA hydrogel (TMP-HA) profoundly accelerated the wound closure in comparison with TMP-loaded INTRASITE Gel (it is a commercial hydrogel), which was evident with the inflammation mitigation, the angiogenesis enhancement, and the collagen deposition. Our work reveals the macrophage-modulatory function of TMP for diabetic wound healing and demonstrates great potential of TMP-HA for clinical application.

Advances in Immunomodulatory Mechanisms of Mesenchymal Stem Cells-Derived Exosome on Immune Cells in Scar Formation

Pathological scars are the result of over-repair and excessive tissue proliferation of the skin injury. It may cause serious dysfunction, resulting in psychological and physiological burdens on the patients. Currently, mesenchymal stem cells-derived exosomes (MSC-Exo) displayed a promising therapeutic effect on wound repair and scar attenuation. But the regulatory mechanisms are opinions vary. In view of inflammation has long been proven as the initial factor of wound healing and scarring, and the unique immunomodulation mechanism of MSC-Exo, the utilization of MSC-Exo may be promising therapeutic for pathological scars. However, different immune cells function differently during wound repair and scar formation. The immunoregulatory mechanism of MSC-Exo would differ among different immune cells and molecules. Herein, this review gave a comprehensive summary of MSC-Exo immunomodulating different immune cells in wound healing and scar formation to provide basic theoretical references and therapeutic exploration of inflammatory wound healing and pathological scars.

The total iridoid glycoside extract of Lamiophlomis rotata Kudo induces M2 macrophage polarization to accelerate wound healing by RAS/ p38 MAPK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Lamiophlomis rotata (Benth.) Kudo (L. rotata), a Tibetan medicinal plant, is used to treat "yellow-water diseases", such as skin disease, jaundice and rheumatism. Our previous study showed that the iridoid glycoside extract of L. rotata (IGLR) is the major constituent of skin wound healing. However, the role of IGLR in the biological process of trauma repair and the probable mechanism of the action remain largely unknown.

AIM OF THE STUDY

To investigate the role of IGLR in the biological process of trauma repair and the probable mechanism of the action.

MATERIALS AND METHODS

The role of IGLR in wound healing was investigated by overall skin wound in mice with Hematoxylin and Eosin (H&E) and Masson trichrome staining. The anti-inflammatory, angiogenesis-promoting and fibril formation effects of IGLR were visualized in wound skin tissue by immunofluorescence staining, and the proinflammatory factors and growth factors were assayed by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Macrophages, dermal fibroblasts, and endothelial cells were cultured to measure the direct/indirect interaction effects of IGLR on the proliferation and migration of cells, and flow cytometry was employed to assess the role of IGLR on macrophage phenotype. Network pharmacology combined with Western blot experiments were conducted to explore possible mechanisms of the actions.

RESULTS

IGLR increased the expression of CD206 (M2 markers) through the RAS/p38 MAPK/NF-κB signaling pathway during wound injury in vivo and in vitro. IGLR suppressed the inflammatory cytokines iNOS, IL-1β and TNF-α in the early stage of wound healing. During the proliferation step of wound repair, IGLR promoted angiogenesis and fibril formation by increasing the expression of VEGF, CD31, TGF-β and α-SMA in wound tissue, and similar results were verified by RT-PCR and ELISA. In a paracrine mechanism, the extract promoted the proliferation of dermal fibroblasts, and endothelial cells were founded by the conditioned medium (CM).

CONCLUSION

IGLR induced M2 macrophage polarization in the early stage of wound healing; in turn, IGLR played a key role in the transition from inflammation to cell proliferation during the biological process of wound healing.

Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives

Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.

Synergy of antioxidant and M2 polarization in polyphenol-modified konjac glucomannan dressing for remodeling wound healing microenvironment

Effective skin wound healing and tissue regeneration remain a challenge. Excessive/chronic inflammation inhibits wound healing, leading to scar formation. Herein, we report a wound dressing composed of KGM-GA based on the natural substances konjac glucomannan (KGM) and gallic acid (GA) that accelerates wound healing without any additional drugs. An in vitro study showed that KGM-GA could not only stimulate macrophage polarization to the anti-inflammatory M2 phenotype but also decrease reactive oxygen species (ROS) levels, indicating excellent anti-inflammatory properties. Moreover, in vivo studies of skin wounds demonstrated that the KGM-GA dressing significantly improved wound healing by accelerating wound closure, collagen deposition, and angiogenesis. In addition, it was observed that KGM-GA regulated M2 polarization, reducing the production of intracellular ROS in the wound microenvironment, which was consistent with the in vitro experiments. Therefore, this study designed a multifunctional biomaterial with biological activity, providing a novel dressing for wound healing.

The total polyphenolic glycoside extract of Lamiophlomis rotata ameliorates hepatic fibrosis through apoptosis by TGF-β/Smad signaling pathway

BACKGROUND

Hepatic fibrosis is characterized by the excessive deposition of extracellular matrix (ECM) which is mainly secreted by activated hepatic stellate cells (HSCs). Lamiophlomis rotata (L. rotata) was recorded to treat jaundice in the traditional Tibetan medical system with the potential of hepatoprotection. However, the bioactivities and the possible mechanism of L. rotata on hepatic fibrosis is still largely unknown.

AIM OF THE STUDY

To investigate the anti-hepatic fibrosis effects of bioactivities in L. rotata and the probable mechanism of action.

MATERIALS AND METHODS

Herein, total polyphenolic glycosides of L. rotata (TPLR) was purified with the selectivity adsorption resin and was analyzed by ultrahigh-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-Q/TOF/MSⁿ). The anti-hepatic fibrosis effect of TPLR was evaluated by carbon tetrachloride (CCl₄)-induced liver fibrosis, and was evaluated with the apoptosis of activated HSCs.

RESULTS

In total, sixteen compounds, including nine phenylpropanoids and six flavonoids, were identified in the UPLC-TOF-MSⁿ profile of the extracts. TPLR significantly ameliorated hepatic fibrosis in CCl₄-induced mice and inhibited HSCs proliferation, Moreover, TPLR notably increased the apoptosis of activated HSCs along with up-regulated caspase-3, -8, -9, and -10. Furthermore, TPLR inhibited TGF-β/Smad pathway ameliorating hepatic fibrosis though downregulation the expression of Smad2/3, Smad4, and upregulation the expression of Smad7 in vivo and in vitro. Simultaneously, the expression of fibronectin (FN), α-smooth muscle actin (α-SMA), and Collagen I (Col1α1) were decreased in tissues and in cells with TPLR administration.

CONCLUSION

These results initially demonstrated that TPLR has the potential to ameliorate hepatic fibrosis through an apoptosis mechanism via TGF-β/Smad signaling pathway.

Macrophages: From Simple Phagocyte to an Integrative Regulatory Cell for Inflammation and Tissue Regeneration-A Review of the Literature

The understanding of macrophages and their pathophysiological role has dramatically changed within the last decades. Macrophages represent a very interesting cell type with regard to biomaterial-based tissue engineering and regeneration. In this context, macrophages play a crucial role in the biocompatibility and degradation of implanted biomaterials. Furthermore, a better understanding of the functionality of macrophages opens perspectives for potential guidance and modulation to turn inflammation into regeneration. Such knowledge may help to improve not only the biocompatibility of scaffold materials but also the integration, maturation, and preservation of scaffold-cell constructs or induce regeneration. Nowadays, macrophages are classified into two subpopulations, the classically activated macrophages (M1 macrophages) with pro-inflammatory properties and the alternatively activated macrophages (M2 macrophages) with anti-inflammatory properties. The present narrative review gives an overview of the different functions of macrophages and summarizes the recent state of knowledge regarding different types of macrophages and their functions, with special emphasis on tissue engineering and tissue regeneration.

Microenvironment-Based Diabetic Foot Ulcer Nanomedicine

Diabetic foot ulcers (DFU), one of the most serious complications of diabetes, are essentially chronic, nonhealing wounds caused by diabetic neuropathy, vascular disease, and bacterial infection. Given its pathogenesis, the DFU microenvironment is rather complicated and characterized by hyperglycemia, ischemia, hypoxia, hyperinflammation, and persistent infection. However, the current clinical therapies for DFU are dissatisfactory, which drives researchers to turn attention to advanced nanotechnology to address DFU therapeutic bottlenecks. In the last decade, a large number of multifunctional nanosystems based on the microenvironment of DFU have been developed with positive effects in DFU therapy, forming a novel concept of "DFU nanomedicine". However, a systematic overview of DFU nanomedicine is still unavailable in the literature. This review summarizes the microenvironmental characteristics of DFU, presents the main progress of wound healing, and summaries the state-of-the-art therapeutic strategies for DFU. Furthermore, the main challenges and future perspectives in this field are discussed and prospected, aiming to fuel and foster the development of DFU nanomedicines successfully.

Macrophage polarization in diabetic wound healing

Impaired wound healing is one of the severe complications of diabetes. Macrophages have been shown to play a vital role in wound healing. In different wound environments, macrophages are classified into two phenotypes: classically activated macrophages and alternatively activated macrophages. Dysregulation of macrophage phenotypes leads to severely impaired wound healing in diabetes. Particularly, uncontrolled inflammation and abnormal macrophage phenotype are important reasons hindering the closure of diabetic wounds. This article reviews the functions of macrophages at various stages of wound healing, the relationship between macrophage phenotypic dysregulation and diabetic wound healing and the mechanism of macrophage polarization in diabetic wound healing. New therapeutic drugs targeting phagocyte polarization to promote the healing of diabetic wounds might provide a new strategy for treating chronic diabetic wound healing.