Mechanistic insight into diabetic wounds: Pathogenesis, molecular targets and treatment strategies to pace wound healing

Nitric oxide-based treatments improve wound healing associated with diabetes mellitus

Non-healing wounds are long-term complications of diabetes mellitus (DM) that increase mortality risk and amputation-related disability and decrease the quality of life. Nitric oxide (NO·)-based treatments (i.e., use of both systemic and topical NO· donors, NO· precursors, and NO· inducers) have received more attention as complementary approaches in treatments of DM wounds. Here, we aimed to highlight the potential benefits of NO·-based treatments on DM wounds through a literature review of experimental and clinical evidence. Various topical NO·-based treatments have been used. In rodents, topical NO·-based therapy facilitates wound healing, manifested as an increased healing rate and a decreased half-closure time. The wound healing effect of NO·-based treatments is attributed to increasing local blood flow, angiogenesis induction, collagen synthesis and deposition, re-epithelization, anti-inflammatory and anti-oxidative properties, and potent broad-spectrum antibacterial effects. The existing literature lacks human clinical evidence on the safety and efficacy of NO·-based treatments for DM wounds. Translating experimental favors of NO·-based treatments of DM wounds into human clinical practice needs conducting clinical trials with well-predefined effect sizes, i.e., wound reduction area, rate of wound healing, and hospital length of stay.

Recombinant human annexin A5 accelerates diabetic wounds healing by regulating skin inflammation

Background

One of the key obstacles to the healing of diabetic wound is the persistence of active inflammation. We previously demonstrated the potential of cell-free fat extract (CEFFE) to promote the healing of diabetic wounds, and annexin A5 (A5) is a crucial anti-inflammatory protein within CEFFE. This study aimed to evaluate the therapeutic potential of A5 in diabetic wounds.

Methods

A5 was loaded into GelMA hydrogels and applied to skin wounds of diabetic mice in vivo. The diabetic wounds with the treatment of GelMA-A5 were observed for 14 days and evaluated by histological analysis. Accessment of inflammation regulation were conducted through anti-CD68 staining, anti-CD86 and anti-CD206 staining, and qRT-PCR of wound tissue. In presence of A5, macrophages stimulated by lipopolysaccharide (LPS) in vitro, and detected through qRT-PCR, flow cytometry, and immunocytofluorescence staining. Besides, epithelial cells were co-cultured with A5 for epithelialization regulation by CCK-8 assay and cell migration assay.

Results

A5 could promote diabetic wound healing and regulate inflammations by promoting the transition of macrophages from M1 to M2 phenotype. In vitro experiments demonstrated that A5 exerted a significant effect on reducing pro-inflammatory factors and inhibiting the polarization of macrophages from M0 toward M1 phenotype. A5 significantly promoted the migration of epithelial cells.

Conclusion

Annexin A5 has a significant impact on the regulation of macrophage inflammation and promotion of epithelialization.

Macrophages: Key players in diabetic wound healing

In this editorial, we discuss the article by Wen et al published. Diabetic foot ulcers are prevalent and serious complications of diabetes, significantly impacting patients’ quality of life and often leading to disability or death, thereby placing a heavy burden on society. Effective diabetic wound healing is hindered by an imbalance in macrophage polarization; many macrophages fail to transition from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, which is crucial for tissue remodelling and repair. The wound healing process is both dynamic and complex. Healthy M1 macrophages, which have strong phagocytic abilities, are vital during the inflammatory phase of diabetic wound healing. However, the failure to transition to M2 macrophages during the proliferative phase hinders wound healing. We anticipate the development of new therapies that can repair damaged M1 macrophages during the inflammatory phase and promote M2 macrophage polarization during the proliferative phase, thereby enhancing the overall healing process.

Oxygen-Bonded Amorphous Transition Metal Dichalcogenides with pH-Responsive Reactive Oxygen Biocatalysis for Combined Antibacterial and Anti-inflammatory Therapies in Diabetic Wound Healing

Diabetic wound healing is a formidable challenge, often complicated by biofilms, immune dysregulation, and hindered vascularization within the wound environments. The intricate interplay of these microenvironmental factors has been a significant oversight in the evolution of therapeutic strategies. Herein, the design of an efficient and versatile oxygen-bonded amorphous transition metal dichalcogenide biocatalyst (aRuS-Or) with pH-responsive reactive oxygen biocatalysis for combined antibacterial and anti-inflammatory therapies in promoting diabetic wound healing is reported. Leveraging the incorporation of Ru─O bonds, aRuS-Or exhibits optimized adsorption/desorption behavior of oxygen intermediates, thereby enhancing both the reactive oxygen species (ROS) generation activity in acidic conditions and ROS scavenging performance in neutral environments. Remarkably, aRuS-Or demonstrates exceptional bactericidal potency within infected milieus through biocatalytic ROS generation. Beyond its antimicrobial capability, post-eradication, aRuS-Or serves a dual role in mitigating oxidative stress in inflammatory wounds, providing robust cellular protection and fostering an M2-phenotype polarization of macrophages, which is pivotal for accelerating the wound repair process. The findings underscore the multifaceted efficacy of aRuS-Or, which harmoniously integrates high antibacterial action with anti-inflammatory and pro-angiogenic properties. This triad of functionalities positions aRuS-Or as a promising candidate for the comprehensive management of complex diabetic ulcers, addressing the unmet needs in the current therapeutics.

3D printed personalized wound dressings using a hydrophobic deep eutectic solvent (HDES)-formulated emulgel

Curcuminoids, known for their antibacterial, anti-inflammatory, and wound healing properties, face challenges in medical applications due to their limited water solubility, resulting in poor bioavailability and clinical efficacy. This study introduces a novel approach to formulating 3D printing ink for personalized wound dressings by utilizing hydrophobic deep eutectic solvents (HDES) to incorporate poorly water-soluble compounds from Curcuma longa (i.e., curcuminoids and ar-turmerone) into hydrogels. The use of HDES, comprising either acetic acid or octanoic acid combined with menthol in a 2 : 1 molar ratio, significantly improved the solubility of curcuminoid derivatives and ar-turmerone by approximately 10 to 600 times, depending on the intrinsic chemical polarities of each compound, compared to conventional extraction solvents (i.e., ethanol and water). By formulating an emulgel using HDES as the oil phase in a gelatin methacryloyl (GelMA) solution stabilized by a biocompatible surfactant, we achieved a 3D biocompatible printing ink with preserved rheological characteristics, enabling the production of personalized wound dressings using a custom-designed, syringe-based 3D printer. The emulgel constructs exhibited regulated swelling profiles, prolonged release of curcuminoids over 60 days as monitored by a Franz cell diffusion assay, and promoted human dermal fibroblast proliferation in vitro. Additionally, the emulgel components worked synergistically with curcuminoids to significantly enhance anti-biofilm activity against Staphylococcus aureus, offering an effective strategy to prevent wound infections. Our findings have demonstrated, for the first time, the formulation of biochemical ink for 3D printing harnessing HDES, providing a new pathway for developing advanced wound dressings with relatively high concentrations of poorly soluble plant bioactive compounds tailored for chronic wound management.

Metformin Syncs CeO2 to Recover Intra- and Extra-Cellular ROS Homeostasis in Diabetic Wound Healing

Excessive generation of reactive oxygen species (ROS) poses a huge obstacle to the healing process of diabetic wounds, resulting in chronic, non-healing wounds. While numerous anti-ROS therapeutics have been developed, satisfied intra- and extra- cellular ROS homeostasis is hard to be established in diabetic wounds. To address this issue, a nanoparticle via loading metformin and CeO2 into mesoporous silica (MSN@Met-CeO2) is designed and synthesized, which is then encapsulated within ROS-responsive hydrogel and shaped as microneedles (MNs) for better application in diabetic wounds. Interestingly, a unique metformin-cerium chelate (Ce· 3Metformin) is formed during the synthesis of MSN@Met-CeO2 MN, which significantly strengthened the inhibitory effect of metformin on mitochondrial complex I. With the presence of Ce· 3Metformin, MSN@Met-CeO2 MN performed a remarkable effect on intracellular mtROS reduction as well as extracellular ROS elimination, the latter is primarily accomplished through the dissociative CeO2 in MSN@Met-CeO2 MN. In the mouse diabetic wound model, MSN@Met-CeO2 MN exhibited a superior pro-healing effect with accelerated inflammation resolution and enhanced angiogenesis, thus highlighting its significant potential for clinical application.

3D Bilayered Hydrogel and Nanofiber Multifunctional Sponge Dressing: An Efficacious Healing Agent for Chronic Wound Healing

Chronic wound management using biomaterial-based dressings has significantly impacted the standard and efficiency of wound healing. However, various available wound healing aids are ineffective in treating deep open injuries and chronic wounds such as diabetic wounds. Herein, we developed a 3D bilayered multifunctional sponge, which addresses the structural and functional issues faced by biomaterial dressings in treating deep and chronic wounds. The 3D bilayered sponge consists of a hydrogel base functionalized with wound healing peptide (Tylotoin)-carrying nanoparticles and topped with a nanofiber layer functionalized with an antimicrobial peptide (LLKKK18). The 3D bilayered sponge, with its highly porous, elastic, and enhanced fluid absorption ability, makes it a suitable wound treatment aid. The developed multifunctional 3D sponge shows antibacterial action and promotes a microenvironment similar to the extracellular matrix (ECM) in regulating dermal cell survival and migration. Study in a full-thickness skin defect diabetic mouse model has shown that the developed 3D bilayered sponge accelerated wound closure and promoted functional skin regeneration through reduced inflammation, faster granulation tissue formation, re-epithelialization, neovascularization, and skin appendage restoration, which make the developed 3D bilayered multifunctional sponge an efficient and advanced chronic wound management aid with potential for future clinical application.

Lysine-Mediated Yttrium Oxide Nanoparticle-Incorporated Nanofibrous Scaffolds with Tunable Cell Adhesion, Proliferation, and Antimicrobial Potency for In Vitro Wound-Healing Applications

The intricate healing mechanism of chronic wounds and their multitude of healing-related obstacles, such as infections, compromised cellular processes, and impediments to the healing process, pose a significant healthcare problem. Exploration of metal oxide nanoparticles, such as yttrium oxide (Y2O3) nanoparticles, can lead to innovative discoveries in the field of chronic wound healing by offering cues that promote cell proliferation in the scaffolds. To achieve this, Y2O3 nanoparticles were synthesized and incorporated within poly(vinyl alcohol) (PVA) nanofibrous scaffolds. Moreover, lysine was infused in the nanofibrous scaffolds to tune its cell adhesion and antimicrobial property. The structure and morphology of the synthesized nanofibers were confirmed through various physicochemical characterizations. Notably, all the fabricated scaffolds have remarkably tuned WVTR values within the range of 2000-2500 g/m2/day, favorable for removing the wound exudate, which facilitate the healing process. The scaffolds exhibited substantial antimicrobial property of approximately 68% and 72.2% against both E. coli and S. aureus at optimized Y2O3 loading. They further prevented the formation of biofilm by 68.6% for S. aureus and 51.2% for P. aeruginosa, suggesting the inhibition of recurrent wound infection. The scaffolds illustrated good blood biocompatibility, cytocompatibility, and cell adhesion capabilities. In vitro ROS inhibition study also corroborated the antioxidant property of the scaffold. Similarly, the wound scratching experiment showed high proliferative capability of a yttria-loaded PVA/lysine (S3) sample through the development of an extracellular matrix support. Molecular insight of wound healing was also validated through flow cytometry analysis and immunocytochemistry imaging studies. The findings revealed increased collagen I (Col-I) expression of approximately 19.48% in cultured fibrocytes. The findings are validated from immunocytochemistry imaging. In summary, the results furnish a captivating paradigm for the use of these scaffolds as a therapeutic biomaterial and to foster their potential efficacy toward wound care management.

ETS1 Expression in Diabetic Foot Ulcers: Implications for Fibroblast Phenotype and Wound Healing Through the PP2A/YAP Pathway

Objective

Diabetic foot ulcers (DFUs) are a serious complication of diabetes, characterized by impaired wound healing and high morbidity and mortality risks. While ETS1 is known to influence fibroblast pathological remodeling, its specific role in DFU and fibroblast wound healing remains unclear.

Methods

Skin tissue samples from DFU patients were categorized by Wagner grades to analyze ETS1 expression. Primary fibroblasts derived from diabetes mellitus wound (DMFBs) were collected from wound margins to test migration ability and analyze cell phenotype by immunofluorescence; they were further treated with siETS1 and the ETS1 inhibitor YK-4-279. Techniques including Western blotting, quantitative Real-Time PCR (qRT-PCR), and immunofluorescence were used to assess the expressionof ETS1, Collagen I, and phenotype in DMFBs. Additionally, the binding sites between human ETS1 and the PP2A promoter were predicted by the UCSC and JASPAR databases. It intended to explore the negative transcriptional regulation of PP2A by ETS1 and its implications in fibroblast function and wound healing.

Results

Fibroblasts derived from Wagner Grades II-IV exhibit differences in cell morphology, migratory ability, and phenotype. Our findings indicate a significant upregulation of ETS1 in Wagner III and IV. The downregulation of ETS1 was observed to enhance DMFB migration and increase the expression of Collagen I and α-SMA. These changes suggest a potential mechanism by which PP2A regulates the YAP/Hippo pathway in diabetic wound healing.

Conclusion

ETS1 appears to impede the repair processes in DFUs, likely through the negative regulation of PP2A, affecting fibroblast function and wound healing.

Promoting diabetic oral mucosa wound healing with a light-responsive hydrogel adaptive to the microenvironment

In diabetic patients, compromised angiogenesis due to endothelial dysfunction leads to delayed intraoral wound healing. However, the moist and dynamic environment of the oral cavity impedes the use of normal wound dressings. Sulfated chitosan (SCS) is a promising biomaterial that promoting angiogenesis. Here, a light-responsive hydrogel combined with SCS explored intraoral wound healing. We designed a SCS-modified hydrogel combined with alginate Methacryloyl (AlgMA) and acrylamide (AM) and demonstrated efficient wet adhesion and mechanical properties suitable for the wet and dynamic oral environment. In vitro, the SAA hydrogel improved the tube formation of human umbilical vein endothelial cells (HUVECs) under high-glucose conditions. Further investigations revealed that the SAA hydrogel can regulate HUVEC-macrophage interactions, leading to a shift in macrophage polarization from M1 to M2, thereby fostering an environment conducive to angiogenesis under high-glucose condition. The results demonstrated the substantial therapeutic impact of the SAA hydrogel on diabetic oral defect repair by effectively enhancing the local blood supply and angiogenesis.

Targeting ferroptosis promotes diabetic wound healing via Nrf2 activation

Wound healing impairment is a frequent diabetes problem leading to amputation. Hyperglycemia induces the overproduction of reactive oxygen species (ROS), iron overload and sustained inflammation, resulting in the persistence of chronic wounds. However, the intrinsic mechanisms of impaired diabetic wound healing remain enigmatic. A new non-apoptotic regulatory cellular death called Ferroptosis, is distinguished by iron-driven lipid peroxidation products accumulation along with insufficient antioxidant enzymes. A decline in antioxidant capacity, excess accumulation of peroxidation of iron and lipid have been identified in wound sites of streptozotocin-induced diabetes mellitus (DM) rats and elevated glucose (EG)-cultured macrophages. Additionally, sustained inflammation and increased inflammatory cytokines were observed in DM rats and HG-cultured macrophages. Importantly, ferrostatin-1 (Fer-1) is a ferroptosis suppressor treatment significantly ameliorated diabetes-related ferroptosis and inflammation. This treatment also enhanced cell proliferation and neovascularization, ultimately thereby accelerating diabetic wound healing. Meanwhile, our study demonstrated that an anti-ferroptotic and anti-inflammatory effects of Fer-1 were mediated through stimulation of nuclear erythroid-associated factor 2 (Nrf2). The current study may provide a new rationale for diabetic wound healing.

PF-PEG@ASIV-EXO Hydrogel Accelerates Diabetic Wound Healing by Ferroptosis Resistance and Promoting Angiogenesis

Astragaloside IV (ASIV) promotes the proliferation of key cells, endothelial progenitor cells (EPCs), during the wound healing process, while exosomes and hydrogels are ideal drug delivery carriers. This study aims to explore the mechanism of action of the "ROS-responsive hydrogel-engineered EPCs-targeted exosomes" composite ASIV delivery system (PF-PEG@ASIV-EXO) in diabetic wound healing. Surface markers of EPCs and PF-PEG@ASIV-EXO were detected separately. The degradation rate of PF-PEG@ASIV-EXO was assessed after coculturing with human dermal fibroblasts (HDF), immortalized human epidermal cells (HaCAT), and human EPCs, and the biocompatibility of EPCs and PF-PEG@ASIV-EXO was evaluated through exosome release and uptake. The effects of PF-PEG@ASIV-EXO on the viability, angiogenesis, ferroptosis, and mitochondria of high-glucose-treated EPCs (HS-EPCs) were investigated. A diabetic wound rat model was established, and the effects of PF-PEG@ASIV-EXO on diabetic wounds were evaluated through HE and Masson staining, as well as levels of VWF, CD31, and ferroptosis in the skin. EPCs were successfully isolated, and PF-PEG@ASIV-EXO was successfully constructed. PF-PEG@ASIV-EXO exhibited a high degradation rate within EPCs, and both EPCs and PF-PEG@ASIV-EXO showed good biocompatibility. PF-PEG@ASIV-EXO promoted the vitality and angiogenesis of EPCs, inhibited ferroptosis, and mitigated mitochondrial damage. Following treatment with PF-PEG@ASIV-EXO, the healing of diabetic rat skin accelerated, accompanied by elevated expression of VWF and CD31, and reduced ferroptosis levels. PF-PEG@ASIV-EXO hydrogel inhibits ferroptosis, promotes angiogenesis, and thereby accelerates the healing of diabetic wounds.

Key biomarkers in type 2 diabetes patients: A systematic review

Type 2 diabetes mellitus (T2DM) is not just a local health issue but a significant global health burden, affecting patient outcomes and clinical management worldwide. Despite the wealth of studies reporting T2DM biomarkers, there is an urgent need for a comparative review. This review aims to provide a comprehensive analysis based on the reported T2DM biomarkers and how these are linked with other conditions, such as inflammation and wound healing. A comparative review was conducted on 24 001 study participants, including 10 024 T2DM patients and 13 977 controls (CTL; age 30-90 years). Four main profiles were extracted and analysed from the clinical reports over the past 11 years: haematological (1084 cases vs. 1458 CTL), protein (6753 cases vs. 9613 CTL), cytokine (975 cases vs. 1350 CTL) and lipid (1212 cases vs. 1556 CTL). This review provides a detailed analysis of the haematological profile in T2DM patients, highlighting fundamental changes such as increased white blood cells and platelet counts, accompanied by decreases in red blood cell counts and iron absorption. In the serum protein profile, a reduction in albumin and anti-inflammatory cytokines was noted along with an increase in globulin levels and pro-inflammatory cytokines. Furthermore, changes in lipid profiles were discussed, specifically the decreases in high-density lipoprotein (HDL) and the increases in low-density lipoprotein (LDL) and triglycerides. Understanding the changes in these four biomarker profiles is essential for developing innovative strategies to create diagnostic and prognostic tools for diabetes management.

Microparticles Decorated with Cell-Instructive Surface Chemistries Actively Promote Wound Healing

Wound healing is a complex biological process involving close crosstalk between various cell types. Dysregulation in any of these processes, such as in diabetic wounds, results in chronic nonhealing wounds. Fibroblasts are a critical cell type involved in the formation of granulation tissue, essential for effective wound healing. 315 different polymer surfaces are screened to identify candidates which actively drive fibroblasts toward either pro- or antiproliferative functional phenotypes. Fibroblast-instructive chemistries are identified, which are synthesized into surfactants to fabricate easy to administer microparticles for direct application to diabetic wounds. The pro-proliferative microfluidic derived particles are able to successfully promote neovascularization, granulation tissue formation, and wound closure after a single application to the wound bed. These active novel bio-instructive microparticles show great potential as a route to reducing the burden of chronic wounds.

In-vitro and in-vivo evaluation of angiogenic potential of a novel lithium chloride loaded silk fibroin / alginate 3D porous scaffold with antibacterial activity, for promoting diabetic wound healing

Healing diabetic ulcers with chronic inflammation is a major challenge for researchers and professionals, necessitating new strategies. To rapidly treat diabetic wounds in rat models, we have fabricated a composite scaffold composed of alginate (Alg) and silk fibroin (SF) as a wound dressing that is laden with molecules of lithium chloride (LC). The physicochemical, bioactivity, and biocompatibility properties of Alg-SF-LC scaffolds were investigated in contrast to those of Alg, SF, and Alg-SF ones. Afterward, full-thickness wounds were ulcerated in diabetic rats in order to evaluate the capacity of LC-laden scaffolds to regenerate skin. The characterization findings demonstrated that the composite scaffolds possessed favorable antibacterial properties, cell compatibility, high swelling, controlled degradability, and good uniformity in the interconnected pore microstructure. Additionally, in terms of wound contraction, re-epithelialization, and angiogenesis improvement, LC-laden scaffolds revealed better performance in diabetic wound healing than the other groups. This research indicates that utilizing lithium chloride molecules loaded in biological materials supports the best diabetic ulcer regeneration in vivo, and produces a skin replacement with a cellular structure comparable to native skin.

Trem2 acts as a non-classical receptor of interleukin-4 to promote diabetic wound healing

BACKGROUND

The immunoglobulin superfamily protein Trem2 (triggering receptor expressed on myeloid cells 2) is primarily expressed on myeloid cells where it functions to regulate macrophage-related immune response induction. While macrophages are essential mediators of diabetic wound healing, the specific regulatory role that Trem2 plays in this setting remains to be established.

OBJECTIVE

This study was developed to explore the potential importance of Trem2 signalling in diabetic wound healing and to clarify the underlying mechanisms through which it functions.

METHODS AND RESULTS

Following wound induction, diabetic model mice exhibited pronounced upregulation of Trem2 expression, which was primarily evident in macrophages. No cutaneous defects were evident in mice bearing a macrophage-specific knockout of Trem2 (T2-cKO), but they induced more pronounced inflammatory responses and failed to effectively repair cutaneous wounds, with lower levels of neovascularization, slower rates of wound closure, decreased collagen deposition following wounding. Mechanistically, we showed that interleukin (IL)-4 binds directly to Trem2, inactivating MAPK/AP-1 signalling to suppress the expression of inflammatory and chemoattractant factors. Co-culture of fibroblasts and macrophages showed that macrophages from T2-cKO mice suppressed the in vitro activation and proliferation of dermal fibroblasts through upregulation of leukaemia inhibitory factor (Lif). Injecting soluble Trem2 in vivo was also sufficient to significantly curtail inflammatory responses and to promote diabetic wound healing.

CONCLUSIONS

These analyses offer novel insight into the role of IL-4/Trem2 signalling as a mediator of myeloid cell-fibroblast crosstalk that may represent a viable therapeutic target for efforts to enhance diabetic wound healing.

M2 Macrophage Polarization and Tissue Remodeling in Autologous Fat Grafting for Diabetic Skin Defects

Autologous adipose tissue was recognized as a promising therapeutic option for soft tissue defects owing to its regenerative potential and ability to facilitate tissue reconstruction. However, the mechanisms by which autologous fat grafting (AFG) promotes healing remain unclear, hindering its potential applications. This study aimed to investigate the distribution and phenotypic transition of infiltrating macrophages in transplanted adipose tissue, as well as their correlation with diabetic skin defect remodeling. Streptozotocin-induced diabetic rats with full-thickness dorsal skin defects were included in this study. The transplanted adipose tissue at the skin defects was collected and analyzed using flow cytometry to determine macrophage proportion and phenotype. The healing of skin defects was evaluated, and treatment was continued until day 14 as the designated endpoint of healing, followed by histopathologic examinations. Immunostaining with CD31 and lymphatic vessel endothelial receptor-1 was performed on wound tissues to analyze angiogenesis and lymphangiogenesis, respectively. Western blot and quantitative polymerase chain reaction analyses were used to assess the expression of the representative genes involved in the healing process. The results showed early polarization of M2 macrophages in the transplanted adipose tissue, concomitant with the upregulation of growth factors and downregulation of inflammatory factors. In vivo experiments revealed that AFG significantly promoted macrophage infiltration and M2 transformation in diabetic skin defects compared to the control groups, thereby promoting tissue extracellular matrix remodeling and lymphatic and vascular regeneration. However, the beneficial effects of AFG were inhibited by macrophage depletion. This study further demonstrated the potential of AFG for treating diabetic skin defects.

Diabetes Mellitus Inhibits Hair Follicle Regeneration by Inducing Macrophage Reprogramming-Mediated Pyroptosis

Background

Diabetes mellitus (DM) is known to inhibit skin self-renewal and hair follicle stem cell (HFSC) activation, which may be key in the formation of chronic diabetic wounds. This study aimed to investigate the reasons behind the suppression of HFSC activation in DM mice.

Methods

Type 1 DM (T1DM) was induced in 6-week-old mice via streptozotocin, and hair follicle growth was subsequently monitored. RNA sequencing, bioinformatics analyses, qRT‒PCR, immunostaining, and cellular experiments were carried out to investigate the underlying mechanisms involved.

Results

T1DM inhibited HFSC activation, which correlated with an increase in caspase-dependent programmed cell death. Additionally, T1DM triggered apoptosis and pyroptosis, predominantly in HFSCs and epidermal regions, with pyroptosis being more pronounced in the inner root sheath of hair follicles. Notably, significant cutaneous immune imbalances were observed, particularly in macrophages. Cellular experiments demonstrated that M1 macrophages inhibited HaCaT cell proliferation and induced cell death, whereas high-glucose environments alone did not have the same effect.

Conclusion

T1DM inhibits HFSC activation via macrophage reprogramming-mediated caspase-dependent pyroptosis, and there is a significant regional characterization of cell death. Moreover, T1DM-induced programmed cell death in the skin may be more closely related to immune homeostasis imbalance than to hyperglycemia itself. These findings shed light on the pathogenesis of diabetic ulcers and provide a theoretical basis for the use of hair follicle grafts in wound repair.

Using Hybrid MnO2-Au Nanoflowers to Accelerate ROS Scavenging and Wound Healing in Diabetes

Objectives: Excessive reactive oxygen species (ROS) in diabetic wounds are major contributors to chronic wounds and impaired healing, posing significant challenges in regenerative medicine. Developing innovative drug delivery systems is crucial to address these issues by modifying the adverse microenvironment and promoting effective wound healing. Methods: Herein, we designed a novel drug delivery platform using manganese dioxide nanoflower hybridized gold nanoparticle composites (MnO2-Au) synthesized via a hydrothermal reaction, and investigated the potential of MnO2-Au nanoflowers to relieve the high oxidative stress microenvironment and regulate diabetic wound tissue healing. Results: This hybrid material demonstrated superior catalytic activity compared to MnO2 alone, enabling the rapid decomposition of hydrogen peroxide and a substantial reduction in ROS levels within dermal fibroblasts. The MnO2-Au nanoflowers also facilitated enhanced dermal fibroblast migration and Col-I expression, which are critical for tissue regeneration. Additionally, a hydrogel-based wound dressing incorporating MnO2-Au nanoflowers was developed, showing its potential as an intelligent drug delivery system. This dressing significantly reduced oxidative stress, accelerated wound closure, and improved the quality of neonatal epithelial tissue regeneration in a diabetic rat skin defect model. Conclusions: Our findings underscore the potential of MnO2-Au nanoflower-based drug delivery systems as a promising therapeutic approach for chronic wound healing, particularly in regenerative medicine.

Skin metabolism in obesity: A narrative review

Obesity is a complex multifactorial disease in which excess body fat triggers negative health effects. Systemically, obesity causes several changes, such as inflammation, oxidative stress, mitochondrial dysfunction and apoptosis; factors linked to the slow and incomplete epithelial regenerative process. Specifically, in the integumentary system, obesity causes an expansion of the skin's surface area and changes in collagen deposition. Molecular underpinnings of why obesity delays wound healing are still poorly understood. In addition to the primary role of dermal adipocytes in lipid storage and heat insulation, they also promote skin immunity, wound healing and hair follicle cycling. As a consequence of the cellular and dysfunctional adaptations of adipocytes, inflammatory immune alterations, alteration in the expression of proteins genes associated with the blood supply, altered collagen formation through fibroblast senescence and excessive degradation of extracellular matrix proteins are metabolic characteristics of the system in obesity that contribute to sustained inflammation and decreased mechanical resistance of the skin.

The emerging role of nanoscaffolds in chronic diabetic wound healing: a new horizon for advanced therapeutics

Non-healing or chronic wounds in extremities that lead to amputations in patients with Type II diabetes (hyperglycemia) are among the most serious and common health problems in the modern world. Over the past decade, more efficient solutions for diabetic ulcers have been developed. Nanofibers and/or composite materials capable of drug delivery, moisture control, and antibacterial effectiveness are increasingly utilized in the formulation of wound dressings, with a particular focus on the biofunctionalization of polymeric and hydrogel materials. Natural products, including plant extracts, honey, antibacterial agents, nanozymes, and metal nanoparticles, are now commonly and effectively implemented to enhance the functionality of wound dressings. Due to the complicated and dysfunctional physiological structure of the chronic wound sites in the extremities of diabetic patients, formulated nanoscaffold or hydrogel components are becoming more intricate and versatile. This study aimed to investigate the development of wound dressing materials over the years while demonstrating their progressively enhanced complexity in effectively targeting, treating, and managing chronic wounds. The mechanisms of action and bio-functionality of wound dressing technologies were elucidated based on findings from 290 studies conducted over the last decade. A notable observation that emerged from these studies is the evolution of wound dressing development technology, which has led to significant advancements in the operational range of smart systems. These include, but are not limited to, self-healing, self-oxygenation, and adaptable mimicry of human tissue.

Deciphering the Dysregulating IGF-1-SP1-CD248 Pathway in Fibroblast Functionality during Diabetic Wound Healing

Reduced fibroblast activity is a critical factor in the progression of diabetic ulcers. CD248, a transmembrane glycoprotein prominently expressed in activated fibroblasts, plays a pivotal role in wound healing. However, the role of CD248 in diabetic wound healing and the CD248 regulatory pathway remains largely unexplored. Our study shows that CD248 expression is significantly reduced in skin wounds from both diabetic patients and mice. Single-cell transcriptome data analyses reveal a marked reduction of CD248-enriched secretory-reticular fibroblasts in diabetic wounds. We identify insulin-like growth factor-1 (IGF-1) as a key regulator of CD248 expression through the Akt/mTOR signaling pathway and the Sp1 transcription factor. Overexpression of CD248 enhances fibroblast motility, elucidating the underrepresentation of CD248-enriched fibroblasts in diabetic wounds. Immunohistochemical staining of diabetic wound samples further confirm low SP1 expression and fewer CD248-positive secretory-reticular fibroblasts. Further investigation reveals that elevated tumor necrosis factor α (TNFα) levels in diabetic environment promotes IGF-1 resistance, and inhibiting IGF-1-induced CD248 expression. In summary, our findings underscore the critical role of the IGF1-SP1-CD248 axis in activating reticular fibroblasts during wound-healing processes. Targeting this axis in fibroblasts could help develop a therapeutic regimen for diabetic ulcers.

Microgels sense wounds' temperature, pH and glucose

Wound healing concerns almost all bed-side related diseases. With our increasing comprehension of healing nature, the physical and chemical natures behind the wound microenvironment have been decoupled. Wound care demands timely screening and prompt diagnosis of wound complications such as infection and inflammation. Biosensor by the way of exhaustive collection, delivery, and analysis of data, becomes indispensable to arrive at an ideal healing upshot and controlling complications by capturing in-situ wound status. Electrochemical based sensors carry some potential unstable performance subjected to the electrical circuitry and power access and contamination. The colorimetric sensors are free from those concerns. We report that microsensors designed from O/W/O of capillary fluids can continuously monitor wound temperature, pH and glucose concentration. We combined three different types of microgels to encapsulate liquid crystals of cholesterol, nontoxic fuel litmus and two glucose-sensitizing enzymes. A smartphone applet was then developed to convert wound healing images to RGB of digitalizing data. The microgel dressing effectively demonstrates the local temperature change, pH and glucose levels of the wound in high resolution where a microgel is a 'pixel'. They are highly responsive, reversible and accurate. Monitoring multiple physicochemical and physiological indicators provides tremendous potential with insight into healing processing.

One-Year Analysis of Autologous Peripheral Blood Mononuclear Cells as Adjuvant Therapy in Treatment of Diabetic Revascularizable Patients Affected by Chronic Limb-Threatening Ischemia: Real-World Data from Italian Registry ROTARI

Wounds in diabetic patients with peripheral arterial disease (PAD) may be poorly responsive to revascularization and conventional therapies. Background/Objective: This study's objective is to analyze the results of regenerative cell therapy with peripheral blood mononuclear cells (PBMNCs) as an adjuvant to revascularization. Methods: This study is based on 168 patients treated with endovascular revascularization below the knee plus three PBMNC implants. The follow-up included clinical outcomes at 1-2-3-6 and 12 months based on amputations, wound healing, pain, and TcPO2. Results: The results at 1 year for 122 cases showed a limb rescue rate of 94.26%, a complete wound healing in 65.59% of patients, and an improvement in the wound area, significant pain relief, and increased peripheral oxygenation. In total, 64.51% of patients completely healed at 6 months, compared to the longer wound healing time reported in the literature in the same cohort of patients, suggesting that PBMNCs have an adjuvant effect in wound healing after revascularization. Conclusions: PBMNC regenerative therapy is a safe and promising treatment for diabetic PAD. In line with previous experiences, this registry shows improved healing in diabetic patients with below-the-knee arteriopathy. The findings support the use of this cell therapy and advocate for further research.

Bioinspired Collagen Scaffold Loaded with bFGF-Overexpressing Human Mesenchymal Stromal Cells Accelerating Diabetic Skin Wound Healing via HIF-1 Signal Pathway Regulated Neovascularization

The healing of severe chronic skin wounds in chronic diabetic patients is still a huge clinical challenge due to complex regeneration processes and control signals. Therefore, a single approach is difficult in obtaining satisfactory therapeutic efficacy for severe diabetic skin wounds. In this study, we adopted a composite strategy for diabetic skin wound healing. First, we fabricated a collagen-based biomimetic skin scaffold. The human basic fibroblast growth factor (bFGF) gene was electrically transduced into human umbilical cord mesenchymal stromal cells (UC-MSCs), and the stable bFGF-overexpressing UC-MSCs (bFGF-MSCs) clones were screened out. Then, an inspired collagen scaffold loaded with bFGF-MSCs was applied to treat full-thickness skin incision wounds in a streptozotocin-induced diabetic rat model. The mechanism of skin damage repair in diabetes mellitus was investigated using RNA-Seq and Western blot assays. The bioinspired collagen scaffold demonstrated good biocompatibility for skin-regeneration-associated cells such as human fibroblast (HFs) and endothelial cells (ECs). The bioinspired collagen scaffold loaded with bFGF-MSCs accelerated the diabetic full-thickness incision wound healing including cell proliferation enhancement, collagen deposition, and re-epithelialization, compared with other treatments. We also showed that the inspired skin scaffold could enhance the in vitro tube formation of ECs and the early angiogenesis process of the wound tissue in vivo. Further findings revealed enhanced angiogenic potential in ECs stimulated by bFGF-MSCs, evidenced by increased AKT phosphorylation and elevated HIF-1α and HIF-1β levels, indicating the activation of HIF-1 pathways in diabetic wound healing. Based on the superior biocompatibility and bioactivity, the novel bioinspired skin healing materials composed of the collagen scaffold and bFGF-MSCs will be promising for healing diabetic skin wounds and even other refractory tissue regenerations. The bioinspired collagen scaffold loaded with bFGF-MSCs could accelerate diabetic wound healing via neovascularization by activating HIF-1 pathways.

Inhibition of CCL7 improves endothelial dysfunction and vasculopathy in mouse models of diabetes mellitus

Diabetic vascular disease is a major complication of diabetes mellitus (DM). Chemokine C-C motif ligand 7 (CCL7) attracts macrophages and monocytes, amplifying inflammatory processes in the vasculature. We hypothesized a causal role for CCL7 in diabetic vasculopathy. CCL7 concentrations were higher in the plasma of patients with type 2 DM, as well as in supernatants from their endothelial progenitor cells (EPCs). High-glucose stimulation increased the secretion of CCL7 from human dermal microvascular endothelial cells (HDMECs) through the c-Fos and c-Jun signaling pathways. CCL7 inhibition using knockdown or neutralization antibody treatment reversed the high glucose-induced impaired tube formation and migration abilities of EPCs, human aortic endothelial cells, human coronary artery endothelial cells, and HDMECs. Administration of recombinant human CCL7 protein impaired tube formation and migration abilities by down-regulating the AKT-endothelial nitric oxide synthase and AKT/nuclear factor erythroid 2-related factor 2/heme oxygenase-1/vascular endothelial growth factor/stromal cell-derived factor-1 pathways and by up-regulating ERK/phosphorylated p65/interleukin-1β/interleukin-6/tumor necrosis factor-α pathways through CC chemokine receptor 3 in endothelial cells. Ccl7 knockout in streptozotocin-treated mice showed improved neovasculogenesis in ischemic limbs and accelerated wound repair, with increased circulating EPCs and capillary density. CCL7 antibody treatment in db/db mice and high-fat diet-induced hyperglycemia mice showed improved neovasculogenesis in ischemic limbs and wound areas, accompanied by up-regulation of angiogenic proteins and down-regulation of inflammatory proteins. Endothelial cell-specific Ccl7-knockout mice showed ameliorated diabetic vasculopathy in streptozotocin-induced DM. This study highlights the potential of CCL7 as a therapeutic target for diabetic vasculopathy.

Nanoarchitectonics of in Situ Antibiotic-Releasing Acicular Nanozymes for Targeting and Inducing Cuproptosis-like Death to Eliminate Drug-Resistant Bacteria

A series of progress has been made in the field of antimicrobial use of nanozymes due to their superior stability and decreased susceptibility to drug resistance. However, catalytically generated reactive oxygen species (ROS) are insufficient for coping with multidrug-resistant organisms (MDROs) in complex wound environments due to their low targeting ability and insufficient catalytic activity. To address this problem, chemically stable copper-gallic acid-vancomycin (CuGA-VAN) nanoneedles were successfully constructed by a simple approach for targeting bacteria; these nanoneedles exhibit OXD-like and GSH-px-like dual enzyme activities to produce ROS and induce bacterial cuproptosis-like death, thereby eliminating MDRO infections. The results of in vitro experiments showed that the free carboxylic acid of GA could react with the free ammonia of teichoic acid in the methicillin-resistant Staphylococcus aureus (MRSA) cell wall skeleton. Thus, CuGA-VAN nanoneedles can rapidly "capture" MRSA in liquid environments, releasing ROS, VAN and Cu2+ on bacterial surfaces to break down the MRSA barrier, destroying the biofilm. In addition, CuGA-VAN effectively promoted wound repair cell proliferation and angiogenesis to facilitate wound healing while ensuring biosafety. According to transcriptome sequencing, highly internalized Cu2+ causes copper overload toxicity; downregulates genes related to the bacterial glyoxylate cycle, tricarboxylic acid cycle, and oxidative respiratory chain; and induces lipid peroxidation in the cytoplasm, leading to bacterial cuproptosis-like death. In this study, CuGA-VAN was cleverly designed to trigger a cascade reaction of targeting, drug release, ROS-catalyzed antibacterial activity and cuproptosis-like death. This provides an innovative idea for multidrug-resistant infections.

The role of SLC7A11 in diabetic wound healing: novel insights and new therapeutic strategies

Diabetic wounds are a severe complication of diabetes, characterized by persistent, non-healing ulcers due to disrupted wound-healing mechanisms in a hyperglycemic environment. Key factors in the pathogenesis of these chronic wounds include unresolved inflammation and antioxidant defense imbalances. The cystine/glutamate antiporter SLC7A11 (xCT) is crucial for cystine import, glutathione production, and antioxidant protection, positioning it as a vital regulator of diabetic wound healing. Recent studies underscore the role of SLC7A11 in modulating immune responses and oxidative stress in diabetic wounds. Moreover, SLC7A11 influences critical processes such as insulin secretion and the mTOR signaling pathway, both of which are implicated in delayed wound healing. This review explores the mechanisms regulating SLC7A11 and its impact on immune response, antioxidant defenses, insulin secretion, and mTOR pathways in diabetic wounds. Additionally, we highlight the current advancements in targeting SLC7A11 for treating related diseases and conceptualize its potential applications and value in diabetic wound treatment strategies, along with the challenges encountered in this context.

Netrin-1 co-cross-linked hydrogel accelerates diabetic wound healing in situ by modulating macrophage heterogeneity and promoting angiogenesis

Diabetic wounds, characterized by prolonged inflammation and impaired vascularization, are a serious complication of diabetes. This study aimed to design a gelatin methacrylate (GelMA) hydrogel for the sustained release of netrin-1 and evaluate its potential as a scaffold to promote diabetic wound healing. The results showed that netrin-1 was highly expressed during the inflammation and proliferation phases of normal wounds, whereas it synchronously exhibited aberrantly low expression in diabetic wounds. Neutralization of netrin-1 inhibited normal wound healing, and the topical application of netrin-1 accelerated diabetic wound healing. Mechanistic studies demonstrated that netrin-1 regulated macrophage heterogeneity via the A2bR/STAT/PPARγ signaling pathway and promoted the function of endothelial cells, thus accelerating diabetic wound healing. These data suggest that netrin-1 is a potential therapeutic target for diabetic wounds.

In Situ Triggered Self-Contraction Bioactive Microgel Assembly Accelerates Diabetic Skin Wound Healing by Activating Mechanotransduction and Biochemical Pathway

Chronic nonhealing skin wounds, characterized by reduced tissue contractility and inhibited wound cell survival under hyperglycemia and hypoxia, present a significant challenge in diabetic care. Here, an advanced self-contraction bioactive core-shell microgel assembly with robust tissue-adhesion (SMART-EXO) is introduced to expedite diabetic wound healing. The SMART-EXO dressing exhibits strong, reversible adhesion to damaged tissue due to abundant hydrogen and dynamic coordination bonds. Additionally, the core-shell microgel components and dynamic coordination bonds provide moderate rigidity, customizable self-contraction, and an interlinked porous architecture. The triggered in situ self-contraction of the SMART-EXO dressing enables active, tunable wound contraction, activating mechanotransduction in the skin and promoting the optimal fibroblast-to-myofibroblast conversion, collagen synthesis, and angiogenesis. Concurrently, the triggered contraction of SMART-EXO facilitates efficient loading and on-demand release of bioactive exosomes, contributing to re-epithelialization and wound microenvironment regulation in diabetic mice. RNA-seq results reveal the activation of critical signaling pathways associated with mechanosensing and exosome regulation, highlighting the combined biomechanical and biochemical mechanisms. These findings underscore SMART-EXO as a versatile, adaptable solution to the complex challenges of diabetic wound care.

Comparative Investigation of Photobiomodulation in Diabetes-Impaired Alveolar Bone Healing: A Histomorphometrical and Molecular Study

Objective: Diabetes mellitus is increasing worldwide. Photobiomodulation (PBM) is proposed as a therapeutic method in various medical concerns. This study aimed to compare the effects of PBM at the wavelengths of 660, 808, or 660 + 808 nm on alveolar bone healing in diabetic rats. Methods: Bilateral maxillary first molars were extracted from diabetic Wistar rats (n = 36). Right-sided sockets were treated by an In-Ga-Al-P laser at 660 nm (7.2 J/cm2, 24 s; DM660), Ga-Al-As laser at 808 nm (7 J/cm2, 14 s; DM808), or a combination of these two sets (DM-dual) (n = 12). Left sides served as controls. On days 7 or 14, specimens were assigned for histomorphometric or real-time PCR analysis of runt-related transcription factor 2, osteocalcin, collagen I, and vascular endothelial growth factor expression. Results: Irradiated sockets of groups DM-808 and DM-dual showed a significant increase in bone tissue and blood vessel establishment as compared to DM-660. Further, group DM-dual exhibited the least amount of fibrotic tissue as compared to the other groups. Conclusions: Within our study limits, the present experiment suggested PBM at 808 nm, alone or combined with 660 nm irradiation, could promote alveolar bone healing, along with minimal fibrosis induction, in diabetic rats.

Unlocking the potential of flavonoid-infused drug delivery systems for diabetic wound healing with a mechanistic exploration

Diabetes is one of the common endocrine disorders generally characterized by elevated levels of blood sugar. It can originate either from the inability of the pancreas to synthesize insulin, which is considered as an autoimmune disorder, or the reduced production of insulin, considered as insulin resistivity. A wound can be defined as a condition of damage to living tissues including skin, mucous membrane and other organs as well. Wounds get complicated with respect to time based on specific processes like diabetes mellitus, obesity and immunocompromised conditions. Proper growth and functionality of the epidermis gets sustained due to impaired diabetic wound healing which shows a sign of dysregulated wound healing process. In comparison with synthetic medications, phytochemicals like flavonoids, tannins, alkaloids and glycosides have gained enormous importance relying on their distinct potential to heal diabetic wounds. Flavonoids are one of the most promising and important groups of natural compounds which can be used to treat acute as well as chronic wounds. Flavonoids show excellent properties due to the presence of hydroxyl groups in their chemical structure, which makes this class of compounds different from others. Based on the novel principles of nanotechnology via utilizing suitable drug delivery systems, the delivery of bioactive constituents from plant source amplifies the wound-healing mechanism, minimizes complexities and enhances bioavailability. Hence, the encapsulation and applicability of flavonoids with an emphasis on mechanistic route and wound-healing therapeutics have been highlighted in the subsequent study with focus on multiple drug delivery systems.

A Knitted and MXenzyme-Integrated Dressing for Geriatrics Diagnosis and Ulcer Healing

Integrated diagnostic and therapeutic dressings are desirable to relieve diabetic patients who often suffer from diabetic foot ulcers (DFUs) and peripheral vascular diseases (PVDs). However, it is highly difficult to monitor the pulse waves with fidelity under wet environments and connect the waveforms to diseases through a small strain sensor. Additionally, immobilizing MXenzyme to regulate spatially heterogeneous levels of reactive oxygen species (ROS) and applying active intervention to enhance ulcer healing on a single structure remain a complex task. To address these issues, we designed a multiscale wearable dressing comprising a knitted all-textile sensing array for quantitatively investigating the pulse wave toward PVD diagnosis. MXenzyme was loaded onto the dressing to provide multiple enzyme mimics for anti-inflammatory activities and deliver electrical stimulation to promote wound growth. In mice, we demonstrate that high and uniform expression of the vascular endothelial growth factor (VEGF) is observed only in the group undergoing dual mediation with electrical stimulation and MXenzyme. This observation indicates that the engineered wound dressing has the capability to accelerate healing in DFU. In human patient evaluations, the engineered dressing distinguishes vascular compliance and pulse period, enabling the diagnosis of arteriosclerosis and return blockage, two typical PVDs. The designed and engineered multiscale dressing achieves the purpose of integrating diagnostic peripheral vessel health monitoring and ulcer healing therapeutics for satisfying the practical clinical requirements of geriatric patients.

OxInflammation Affects Transdifferentiation to Myofibroblasts, Prolonging Wound Healing in Diabetes: A Systematic Review

Skin wounds, primarily in association with type I diabetes mellitus, are a public health problem generating significant health impacts. Therefore, identifying the main pathways/mechanisms involved in differentiating fibroblasts into myofibroblasts is fundamental to guide research into effective treatments. Adopting the PRISMA guidelines, this study aimed to verify the main pathways/mechanisms using diabetic murine models and analyze the advances and limitations of this area. The Medline (PubMed), Scopus, and Web of Science platforms were used for the search. The studies included were limited to those that used diabetic murine models with excisional wounds. Bias analysis and methodological quality assessments were undertaken using the SYRCLE bias risk tool. Eighteen studies were selected. The systematic review results confirm that diabetes impairs the transformation of fibroblasts into myofibroblasts by affecting the expression of several growth factors, most notably transforming growth factor beta (TGF-beta) and NLRP3. Diabetes also compromises pathways such as the SMAD, c-Jun N-terminal kinase, protein kinase C, and nuclear factor kappa beta activating caspase pathways, leading to cell death. Furthermore, diabetes renders the wound environment highly pro-oxidant and inflammatory, which is known as OxInflammation. As a consequence of this OxInflammation, delays in the collagenization process occur. The protocol details for this systematic review were registered with PROSPERO: CRD42021267776.

A novel chitosan-PEG hydrogel embedded with in situ silver nanoparticles of Clerodendrum glandulosum Lindl. extract: evaluation of its in vivo diabetic wound healing properties using an image-guided machine learning model

The pathophysiology of chronic wounds related to diabetes mellitus is a result of a series of complications induced by hyperglycemia. The symptoms include impaired growth factor production, decreased keratinocyte proliferation and migration, reduced angiogenesis and cytokine synthesis, lowered matrix metalloproteinase (MMP) production, neuropathy, reduced nitric oxide synthase production, decreased fibroblast synthesis and migration, and impaired inflammatory cell functions. This multifaceted mechanism of diabetic wounds needs a suitable novel topical formulation that can deliver the active constituent by a controlled means, target the various stages of wound healing, absorb the wound exudates, and prevent secondary infections. To meet the above requirements, the Clerodendrum glandulosum (CG) extract reduced silver nanoparticle (AgNP) impregnated chitosan-polyethylene glycol (PEG) hydrogel was synthesized. The findings of the physicochemical characterization studies suggested that the hydrogel exhibited excellent formulation characteristics and showed controlled release for seven days, making it suitable for chronic wound healing studies. In subsequent studies, these formulations showed good antioxidant and antimicrobial properties, and hemocompatibility, with the least cytotoxic properties. The results of the diabetic wound healing studies showed a faster wound closure rate and improved extracellular matrix formation. These antioxidant, antimicrobial, anti-inflammatory and wound-healing properties suggest that the CG-AgNP loaded chitosan-PEG hydrogel is a promising material for novel topical formulation of diabetic wounds.

Phytoconstituents as modulators of NF-κB signalling: Investigating therapeutic potential for diabetic wound healing

The NF-κB pathway plays a pivotal role in impeding the diabetic wound healing process, contributing to prolonged inflammation, diminished angiogenesis, and reduced proliferation. In contrast to modern synthetic therapies, naturally occurring phytoconstituents are well-studied inhibitors of the NF-κB pathway that are now attracting increased attention in the context of diabetic wound healing because of lower toxicity, better safety and efficacy, and cost-effectiveness. This study explores recent research on phytoconstituent-based therapies and delve into their action mechanisms targeting the NF-κB pathway and potential for assisting effective healing of diabetic wounds. For this purpose, we have carried out surveys of recent literature and analyzed studies from prominent databases such as Science Direct, Scopus, PubMed, Google Scholar, EMBASE, and Web of Science. The classification of phytoconstituents into various categorie such as: alkaloids, triterpenoids, phenolics, polyphenols, flavonoids, monoterpene glycosides, naphthoquinones and tocopherols. Noteworthy phytoconstituents, including Neferine, Plumbagin, Boswellic acid, Genistein, Luteolin, Kirenol, Rutin, Vicenin-2, Gamma-tocopherol, Icariin, Resveratrol, Mangiferin, Betulinic acid, Berberine, Syringic acid, Gallocatechin, Curcumin, Loureirin-A, Loureirin-B, Lupeol, Paeoniflorin, and Puerarin emerge from these studies as promising agents for diabetic wound healing through the inhibition of the NF-κB pathway. Extensive research on various phytoconstituents has revealed how they modulate signalling pathways, including NF-κB, studies that demonstrate the potential for development of therapeutic phytoconstituents to assist healing of chronic diabetic wounds.

Teicoplanin-Decorated Reduced Graphene Oxide Incorporated Silk Protein Hybrid Hydrogel for Accelerating Infectious Diabetic Wound Healing and Preventing Diabetic Foot Osteomyelitis

Developing hybrid hydrogel dressings with anti-inflammatory, antioxidant, angiogenetic, and antibiofilm activities with higher bone tissue penetrability to accelerate diabetic wound healing and prevent diabetic foot osteomyelitis (DFO) is highly desirable in managing diabetic wounds. Herein, the glycopeptide teicoplanin is used for the first time as a green reductant to chemically reduce graphene oxide (GO). The resulting teicoplanin-decorated reduced graphene oxide (rGO) is incorporated into a mixture of silk proteins (SP) and crosslinked with genipin to yield a physicochemically crosslinked rGO-SP hybrid hydrogel. This hybrid hydrogel exhibits high porosity, self-healing, shear-induced thinning, increased cell proliferation and migration, and mechanical properties suitable for tissue engineering. Moreover, the hybrid hydrogel eradicates bacterial biofilms with a high penetrability index in agar and hydroxyapatite disks covered with biofilms, mimicking bone tissue. In vivo, the hybrid hydrogel accelerates the healing of noninfected wounds in a diabetic rat and infected wounds in a diabetic mouse by upregulating anti-inflammatory cytokines and downregulating matrix metalloproteinase-9, promoting M2 macrophage polarization and angiogenesis. The implantation of hybrid hydrogel into the infected site of mouse tibia improves bone regeneration. Hence, the rGO-SP hybrid hydrogel can be a promising wound dressing for treating infectious diabetic wounds, providing a further advantage in preventing DFO.

Citric acid cross-linked pomegranate peel extract-loaded pH-responsive β-cyclodextrin/carboxymethyl tapioca starch hydrogel film for diabetic wound healing

Pomegranate peel extract (PPE) hydrogel films filled with citric acid (CA) and β-cyclodextrin-carboxymethyl tapioca starch (CMS) were designed mainly to prevent wound infections and speed up the healing process. FTIR and NMR studies corroborated the carboxymethylation of neat tapioca starch (NS). CMS exhibited superior swelling behavior than NS. The amount of CA and β-CD controlled the physicochemical parameters of developed PPE/CA/β-CD/CMS films. Optimized film (OF) exhibited acceptable swellability, wound fluid absorptivity, water vapor transmission rate, water contact angle, and mechanical properties. Biodegradable, biocompatible, and antibacterial films exhibited pH dependence in the release of ellagic acid for up to 24 h. In mice model, PPE/CA/β-CD/CMS hydrogel film treatment showed promising wound healing effects, including increased collagen deposition, reduced inflammation, activation of the Wingless-related integration site (wnt) pathway leading to cell division, proliferation, and migration to the wound site. The expression of the WNT3A gene did not show any significant differences among all the studied groups. Developed PPE-loaded CA/β-CD/CMS film promoted wound healing by epithelialization, granulation tissue thickness, collagen deposition, and angiogenesis, hence could be recommended as a biodegradable and antibacterial hydrogel platform to improve the cell proliferation during the healing of diabetic wounds.

Ghrelin induced by ultraviolet B exposure promotes the restoration of diabetic cutaneous wound healing

BACKGROUND

Diabetes mellitus (DM) presents impediment to wound healing. While ultraviolet B (UVB) exposure showed therapeutic potential in various skin conditions, its capacity to mediate diabetic wound healing remains unclear. To investigate the efficacy of UVB on wound healing and its underlying basis.

MATERIALS AND METHODS

Male C57BL/6 mice were subjected to the high-fat diet followed by streptozotocin administration to establish the diabetic model. Upon confirmation of diabetes, full-thickness wounds were inflicted and the treatment group received UVB radiation at 50 mJ/cm2 for 5 min every alternate day for 2 weeks. Wound healing rate was then assessed, accompanied by evaluations of blood glucose, lipid profiles, CD31 expression, and concentrations of ghrelin and leptin. Concurrently, in vitro studies were executed to evaluate the protective role of ghrelin on human umbilical vein endothelial cells (HUVEC) under high glucose (HG) conditions.

RESULTS

Post UVB exposure, there was a marked acceleration in wound healing in DM mice without alterations in hyperglycemia and lipid profiles. Compared to non-UVB-exposed mice, the UVB group showed enhanced angiogenesis manifested by a surge in CD31 expression. This trend appeared to be in harmony with the elevated ghrelin levels. In vitro experiments indicated that ghrelin significantly enhanced the migratory pace and angiogenic properties of HUVEC under HG-induced stress, potentially mediated by an upregulation in vascular endothelial growth factor expression.

CONCLUSION

UVB exposure bolstered wound healing in diabetic mice, plausibly mediated through augmented angiogenesis induced by ghrelin secretion. Such findings underscore the vast potential of UVB-induced ghrelin in therapeutic strategies targeting diabetic wound healing.

MG53 binding to CAV3 facilitates activation of eNOS/NO signaling pathway to enhance the therapeutic benefits of bone marrow-derived mesenchymal stem cells in diabetic wound healing

Impaired wound healing in diabetes results from a complex interplay of factors that disrupt epithelialization and wound closure. MG53, a tripartite motif (TRIM) family protein, plays a key role in repairing cell membrane damage and facilitating tissue regeneration. In this study, bone marrow-derived mesenchymal stem cells (BMSCs) were transduced with lentiviral vectors overexpressing MG53 to investigate their efficacy in diabetic wound healing. Using a db/db mouse wound model, we observed that BMSCs-MG53 significantly enhanced diabetic wound healing. This improvement was associated with marked increase in re-epithelialization and vascularization. BMSCs-MG53 promoted recruitment and survival of BMSCs, as evidenced by an increase in MG53/Ki67-positive BMSCs and their improved response to scratch wounding. The combination therapy also promoted angiogenesis in diabetic wound tissues by upregulating the expression of angiogenic growth factors. MG53 overexpression accelerated the differentiation of BMSCs into endothelial cells, manifested as the formation of mature vascular network structure and a remarkable increase in DiI-Ac-LDL uptake. Our mechanistic investigation revealed that MG53 binds to caveolin-3 (CAV3) and subsequently increases phosphorylation of eNOS, thereby activating eNOS/NO signaling. Notably, CAV3 knockdown reversed the promoting effects of MG53 on BMSCs endothelial differentiation. Overall, our findings support the notion that MG53 binds to CAV3, activates eNOS/NO signaling pathway, and accelerates the therapeutic effect of BMSCs in the context of diabetic wound healing. These insights hold promise for the development of innovative strategies for treating diabetic-related impairments in wound healing.

A multifunctional injectable, self-healing, and adhesive hydrogel-based wound dressing stimulated diabetic wound healing with combined reactive oxygen species scavenging, hyperglycemia reducing, and bacteria-killing abilities

The proficient handling of diabetic wounds, a rising issue coinciding with the global escalation of diabetes cases, poses significant clinical difficulties. A range of biofunctional dressings have been engineered and produced to expedite the healing process of diabetic wounds. This study proposes a multifunctional hydrogel dressing for diabetic wound healing, which is composed of Polyvinyl Alcohol (PVA) and N1-(4-boronobenzyl)-N3-(4-boronophenyl)-N1, N1, N3, N3-teramethylpropane-1, 3-diaminium (TSPBA), and a dual-drug loaded Gelatin methacryloyl (GM) microgel. The GM microgel is loaded with sodium fusidate (SF) and nanoliposomes (LP) that contain metformin hydrochloride (MH). Notably, adhesive and self-healing properties the hydrogel enhance their therapeutic potential and ease of application. In vitro assessments indicate that SF-infused hydrogel can eliminate more than 98% of bacteria within 24 h and maintain a sustained release over 15 days. Additionally, MH incorporated within the hydrogel has demonstrated effective glucose level regulation for a duration exceeding 15 days. The hydrogel demonstrates a sustained ability to neutralize ROS throughout the entire healing process, predominantly by electron donation and sequestration. This multifunctional hydrogel dressing, which integrated biological functions of efficient bactericidal activity against both MSSA and MRSA strains, blood glucose modulation, and control of active oxygen levels, has successfully promoted the healing of diabetic wounds in rats in 14 days. The hydrogel dressing exhibited significant effectiveness in facilitating the healing process of diabetic wounds, highlighting its considerable promise for clinical translation.

Mechanism and application of fibrous proteins in diabetic wound healing: a literature review

Diabetic wounds are more complex than normal chronic wounds because of factors such as hypoxia, reduced local angiogenesis, and prolonged inflammation phase. Fibrous proteins, including collagen, fibrin, laminin, fibronectin, elastin etc., possess excellent inherent properties that make them highly advantageous in the area of wound healing. Accumulating evidence suggests that they contribute to the healing process of diabetic wounds by facilitating the repair and remodel of extracellular matrix, stimulating the development of vascular and granulation tissue, and so on. However, there is currently a lack of a comprehensive review of the application of these proteins in diabetes wounds. An overview of fibrous protein characteristics and the alterations linked to diabetic wounds is given in this article's initial section. Next is a summary of the advanced applications of fibrous proteins in the last five years, including acellular dermal matrix, hydrogel, foam, scaffold, and electrospun nanofibrous membrane. These dressings have the ability to actively promote healing in addition to just covering wounds compared to traditional wound dressings like gauze or bandage. Research on fibrous proteins and their role in diabetic wound healing may result in novel therapeutic modalities that lower the incidence of diabetic wounds and thereby enhance the health of diabetic patients.

Key extracellular proteins and TF-miRNA co-regulatory network in diabetic foot ulcer: Bioinformatics and experimental insights

BACKGROUND

Diabetic foot ulcers (DFUs), a serious complication of diabetes, are associated with abnormal extracellular protein (EP) metabolism. The identification of key EPs and their regulatory networks is crucial for the understanding of DFU formation and development of effective treatments. In this study, a large-scale bioinformatics analysis was conducted to identify potential therapeutic targets and experimental validation was performed to ensure the reliability and biological relevance of the findings.

METHODS

Due to the comprehensive profiling of DFU samples provided by the GSE80178 dataset, we initially selected it to derive differentially expressed genes (DEGs) associated with DFU. Subsequently, utilizing the UniProt database and annotated EP list from the Human Protein Atlas annotation database, we screened for extracellular protein-related differentially expressed genes (EP-DEGs) due to their crucial role in the pathogenesis and healing of DFU. We examined EP-DEG pathway enrichment and protein-protein interaction networks, analyzed paired full-thickness skin tissue samples from 24 patients with DFUs and healthy controls, and performed polymerase chain reaction (PCR) experiments to validate candidate genes. Ultimately, we constructed a transcription factor (TF)-microRNA (miRNA)-hub gene co-regulatory network to explore upstream and downstream regulatory connections based on validated DEGs.

RESULTS

Four crucial candidate genes (FMOD, LUM, VCAN, and S100A12) were identified and verified via PCR analysis. The TF-miRNA-hub EP-DEG regulatory network contained the pivotal TFs TRIM28 and STAT3 and the miRNAs hsa-mir-20a-5p, hsa-miR-21, and hsa-miR-203.

CONCLUSION

The findings of this study advance our understanding of the pathology of DFU by defining key roles of specific EPs and elucidating a comprehensive regulatory network. These insights pave the way for novel approaches to improve DFU treatment outcomes.

Bioengineered mesenchymal stem cell-derived exosomes: emerging strategies for diabetic wound healing

Diabetic wounds are among the most common complications of diabetes mellitus and their healing process can be delayed due to persistent inflammatory reactions, bacterial infections, damaged vascularization and impaired cell proliferation, which casts a blight on patients'health and quality of life. Therefore, new strategies to accelerate diabetic wound healing are being positively explored. Exosomes derived from mesenchymal stem cells (MSC-Exos) can inherit the therapeutic and reparative abilities of stem cells and play a crucial role in diabetic wound healing. However, poor targeting, low concentrations of therapeutic molecules, easy removal from wounds and limited yield of MSC-Exos are challenging for clinical applications. Bioengineering techniques have recently gained attention for their ability to enhance the efficacy and yield of MSC-Exos. In this review, we summarise the role of MSC-Exos in diabetic wound healing and focus on three bioengineering strategies, namely, parental MSC-Exos engineering, direct MSC-Exos engineering and MSC-Exos combined with biomaterials. Furthermore, the application of bioengineered MSC-Exos in diabetic wound healing is reviewed. Finally, we discuss the future prospects of bioengineered MSC-Exos, providing new insights into the exploration of therapeutic strategies.

Periplaneta americana extract promotes infectious diabetic ulcers wound healing by downregulation of LINC01133/SLAMF9

Wound healing in diabetic ulcers remains a significant clinical challenge, primarily due to bacterial infection and impaired angiogenesis. Periplaneta americana extract (PAE) has been widely used to treat diabetic wounds, yet its underlying mechanisms are not fully understood. This study aimed to elucidate these mechanisms by analyzing long non-coding RNA (lncRNA) expressions in the wound tissues from diabetic anal fistula patients treated with or without PAE, using high-throughput sequencing. Peripheral blood monocytes from patients were differentiated into M0 macrophages with human macrophage colony-stimulating factor (hM-CSF) and subsequently polarized into M1 macrophages with lipopolysaccharide. The results indicated that LINC01133 and SLAMF9 were downregulated in wound tissues of patients treated with PAE. Furthermore, PAE suppressed M1 macrophage polarization and enhanced human umbilical vein endothelial cell (HUVEC) proliferation, migration, and angiogenesis. These effects were diminished when LINC01133 or SLAMF9 were overexpressed. Mechanistically, LINC01133 was shown to upregulate SLAMF9 through interaction with ELAVL1. Overexpression of SLAMF9 reversed the effects of LINC01133 silencing on macrophage polarization and HUVEC functions. In conclusion, PAE facilitates the healing of infected diabetic ulcers by downregulating the LINC01133/SLAMF9 pathway.

Preconditioning Local Injection of Activated Platelet-Rich Plasma Increases Angiogenesis, VEGF Levels, and Viability of Modified McFarlane Flap in Diabetes-Induced Rats

Background  The risk of flap necrosis in tissue reconstruction surgery is elevated in patients with vascular disorders, such as diabetes mellitus. Chronic hyperglycemia causes endothelial cell dysfunction and increases inflammatory process, causing vascular insufficiency. Platelet-rich plasma (PRP) contains high levels of platelets, growth factors, and fibrinogens. Its regenerative properties spark interest in supporting flap survival in relation to diabetic complications. Methods  Thirty Wistar rats were divided into three groups. The first group included diabetic rats without PRP injection, which underwent flap procedure. The second group included diabetes-induced rats receiving PRP subcutaneous injection 1 day prior to flap procedure. The third group included nondiabetic rats receiving PRP injection 1 day prior to flap procedure. Flap tissue samples were taken on the seventh day to measure vascular endothelial growth factor (VEGF) levels using enzyme-linked immunosorbent assay method; angiogenesis and collagen density were measured from histopathology examination, and flap viability was analyzed using digital measurements. Results  Analysis showed that flap viability, angiogenesis, and VEGF levels were significantly higher in the PRP-injected diabetic rats compared with diabetic rats that did not receive PRP. The levels of VEGF, angiogenesis, and viability of flaps in diabetic rats given PRP did not differ significantly compared with nondiabetic rats that received PRP. Conclusion  Flap preconditioning through local injection of activated PRP enhances flap viability, VEGF levels and angiogenesis, in random skin flaps in diabetic rats, to the level where it does not differ significantly to nondiabetic rats that were given PRP.

Phenylboronic acid functionalized dextran loading curcumin as nano-therapeutics for promoting the bacteria-infected diabetic wound healing

Chronic bacterial infections, excessive inflammation, and oxidative stress significantly hinder diabetic wound healing by prolonging the inflammatory phase and complicating the healing process. In this study, phenylboronic acid functionalized dextran (PODP) was developed to encapsulate curcumin, referred to as PODP@Cur. Experimental results indicate that PODP significantly improves the water solubility of curcumin and exhibits synergistic biological activity both in vitro and in vivo. PODP@Cur is capable of accelerating drug release under the pathological microenvironment with ROS accumulation. Furthermore, phenylboronic acid (PBA) has demonstrated potential for targeted bacterial drug delivery, enhancing antibacterial efficacy and trapping free LPS/PGN from dead bacteria to reduce undesirable inflammation. In a diabetic mouse model, PODP@Cur exhibits an excellent antibacterial, anti-inflammatory and antioxidant activities to ultimately promote the efficient and safe wound healing. Due to the specific interaction between PBA and LPS, PODP@Cur could enhance antibacterial activity against bacteria, reduce toxic side effects on normal cells, and alleviate the LPS-mediated pro-inflammatory pathological microenvironment. Therefore, PODP@Cur is capable of being exploited as an efficient and safe candidate for promoting the bacteria-infected diabetic wound healing.

Advances in skin gene therapy: utilizing innovative dressing scaffolds for wound healing, a comprehensive review

The skin, serving as the body's outermost layer, boasts a vast area and intricate structure, functioning as the primary barrier against external threats. Disruptions in the composition and functionality of the skin can lead to a diverse array of skin conditions, such as wounds, burns, and diabetic ulcers, along with inflammatory disorders, infections, and various types of skin cancer. These disorders not only exacerbate concerns regarding skin health and beauty but also have a significant impact on mental well-being. Due to the complexity of these disorders, conventional treatments often prove insufficient, necessitating the exploration of new therapeutic approaches. Researchers develop new therapies by deciphering these intricacies and gaining a thorough understanding of the protein networks and molecular processes in skin. A new window of opportunity has opened up for improving wound healing processes because of recent advancements in skin gene therapy. To enhance skin regeneration and healing, this extensive review investigates the use of novel dressing scaffolds in conjunction with gene therapy approaches. Scaffolds that do double duty as wound protectors and vectors for therapeutic gene delivery are being developed using innovative biomaterials. To improve cellular responses and speed healing, these state-of-the-art scaffolds allow for the targeted delivery and sustained release of genetic material. The most recent developments in gene therapy techniques include RNA interference, CRISPR-based gene editing, and the utilization of viral and non-viral vectors in conjunction with scaffolds, which were reviewed here to overcome skin disorders and wound complications. In the future, there will be rare chances to develop custom methods for skin health care thanks to the combination of modern technology and collaboration among disciplines.

Antibacterial polylysine-containing hydrogels for hemostatic and wound healing applications: preparation methods, current advances and future perspectives

The treatment of various types of wounds such as dermal wounds, multidrug resistant bacteria-infected wounds, and chronic diabetic wounds is one of the critical challenges facing healthcare systems. Delayed wound healing can impose a remarkable burden on patients and health care professionals. In this case, given their unique three-dimensional porous structure, biocompatibility, high hydrophilicity, capability to provide a moist environment while absorbing wound exudate, permeability to both gas and oxygen, and tunable mechanical properties, hydrogels with antibacterial function are one of the most promising candidates for wound healing applications. Polylysine is a cationic polymer with the advantages of inherent antibacterial properties, biodegradability, and biocompatibility. Therefore, its utilization to engineer antibacterial hydrogels for accelerating wound healing is of great interest. In this review, we initially discuss polylysine properties, and then focus on the most recent advances in polylysine-containing hydrogels (since 2016) prepared using various chemical and physical crosslinking methods for hemostasis and wound healing applications. Finally, the challenges and future directions in the engineering of these antibacterial hydrogels for wound healing are discussed.

Recent advances in the use of extracellular vesicles from adipose-derived stem cells for regenerative medical therapeutics

Adipose-derived stem cells (ADSCs) are a subset of mesenchymal stem cells (MSCs) isolated from adipose tissue. They possess remarkable properties, including multipotency, self-renewal, and easy clinical availability. ADSCs are also capable of promoting tissue regeneration through the secretion of various cytokines, factors, and extracellular vesicles (EVs). ADSC-derived EVs (ADSC-EVs) act as intercellular signaling mediators that encapsulate a range of biomolecules. These EVs have been found to mediate the therapeutic activities of donor cells by promoting the proliferation and migration of effector cells, facilitating angiogenesis, modulating immunity, and performing other specific functions in different tissues. Compared to the donor cells themselves, ADSC-EVs offer advantages such as fewer safety concerns and more convenient transportation and storage for clinical application. As a result, these EVs have received significant attention as cell-free therapeutic agents with potential future application in regenerative medicine. In this review, we focus on recent research progress regarding regenerative medical use of ADSC-EVs across various medical conditions, including wound healing, chronic limb ischemia, angiogenesis, myocardial infarction, diabetic nephropathy, fat graft survival, bone regeneration, cartilage regeneration, tendinopathy and tendon healing, peripheral nerve regeneration, and acute lung injury, among others. We also discuss the underlying mechanisms responsible for inducing these therapeutic effects. We believe that deciphering the biological properties, therapeutic effects, and underlying mechanisms associated with ADSC-EVs will provide a foundation for developing a novel therapeutic approach in regenerative medicine.