Negative pressure wound therapy promotes wound healing by suppressing macrophage inflammation in diabetic ulcers

Negative Pressure Wound Therapy for Chronic Wounds

ABSTRACT

Chronic wounds, including those caused by venous and arterial insufficiency, diabetic complications, and pressure-induced ulcers, pose significant treatment challenges. Negative pressure wound therapy has been increasingly used for managing these wounds. This treatment aims to promote wound healing, prepare the wound bed for further surgical intervention, minimize the risk of infection, and potentially shorten the time to wound healing. Considering variances in techniques applied in different regions globally, there is an emerging need to comprehensively evaluate the effectiveness of negative pressure wound therapy on chronic wounds. Unfortunately, detailed descriptions of the techniques applied to achieve negative pressure are often lacking in existing literature abstracts, posing challenges for direct comparisons. This review aims to analyze the application of negative pressure wound therapy in the treatment of chronic wounds, summarize its advantages and disadvantages, and further explore the potential value and future research direction of negative pressure wound therapy in the repair of chronic wounds.

A Novel Food Bore Protein Hydrogel with Silver Ions for Promoting Burn Wound Healing

Hydrogels have emerged as a promising option for treating local scald wounds due to their unique physical and chemical properties. This study aims to evaluate the efficacy of ovalbumin/gelatin composite hydrogels in repairing deep II-degree scald wounds using a mouse dorsal skin model. Trauma tissues collected at various time points are analyzed for total protein content, hydroxyproline content, histological features, and expression of relevant markers. The results reveal that the hydrogel accelerates the healing process of scalded wounds, which is 17.27% higher than the control group. The hydrogel treatment also effectively prevents wound enlargement and redness of the edges caused by infection during the initial stage of scalding. The total protein and hydroxyproline content of the treated wounds are significantly elevated. Additionally, the hydrogel up-regulates the expression of VEGF (a crucial angiogenic factor) and down-regulates CD68 (a macrophage marker). In summary, this study provides valuable insights into the potential of multifunctional protein-based hydrogels in wound healing.

Effect of Diabetes on Wound Healing: A Bibliometrics and Visual Analysis

Objective

The quality of life of diabetic patients is seriously affected by wound healing difficulty, which can lead to increased infection, skin deep tissue injury and continuous pain. By analyzing the research trends and hot spots in this field, the visualization analysis map is constructed.

Methods

The contents of the selected articles were sorted out and analyzed by bibliometrics. We use CiteSpace, Vosviewer and HistCite to visualize literature information, including national publication statistics, institutions, authors, journal partnerships, and citations of published articles.

Results

Among the 2942 articles, the United States and China ranked first in both article circulation and TGCS, and many countries also cooperated. The collaboration between schools and research institutions is a core part of dissertation research institution collaboration, with most authors coming from the same institution. Most of the literature studies on the mechanisms and methods of promoting diabetic wound healing. Improving cell function or making innovative attempts in local treatment are the fruits of researchers' efforts to promote diabetic wound healing in recent years.

Conclusion

Through the metrology method, the time distribution, author institution, cooperation network, research status, research hotspot and development trend of the literature on the influence of diabetes on wound healing were intuitively displayed, which provided a reference for further research and development direction.

Research progress on and molecular mechanism of vacuum sealing drainage in the treatment of diabetic foot ulcers

Diabetic foot ulcers (DFUs) are common chronic wounds and a common complication of diabetes. The foot is the main site of diabetic ulcers, which involve small and medium-sized arteries, peripheral nerves, and microcirculation, among others. DFUs are prone to coinfections and affect many diabetic patients. In recent years, interdisciplinary research combining medicine and material science has been increasing and has achieved significant clinical therapeutic effects, and the application of vacuum sealing drainage (VSD) in the treatment of DFUs is a typical representative of this progress, but the mechanism of action remains unclear. In this review, we integrated bioinformatics and literature and found that ferroptosis is an important signaling pathway through which VSD promotes the healing of DFUs and that System Xc-GSH-GPX4 and NAD(P)H-CoQ10-FSP1 are important axes in this signaling pathway, and we speculate that VSD is most likely to inhibit ferroptosis to promote DFU healing through the above axes. In addition, we found that some classical pathways, such as the TNF, NF-κB, and Wnt/β-catenin pathways, are also involved in the VSD-mediated promotion of DFU healing. We also compiled and reviewed the progress from clinical studies on VSD, and this information provides a reference for the study of VSD in the treatment of DFUs.

Exploring an Innovative Approach: Integrating Negative-Pressure Wound Therapy with Silver Nanoparticle Dressings in Skin Graft Procedures

BACKGROUND

Skin grafting is a helpful instrument in a plastic surgeon's arsenal. Several types of dressings were designed to facilitate the process of graft integration. Negative-pressure wound therapy is a proven dressing method, enhancing graft survival through several mechanisms: aspiration of secretions, stimulation of neoangiogenesis, and promotion of an anti-inflammatory environment. Silver nanoparticle dressings also bring multiple benefits by bearing an antimicrobial effect and providing a humid medium, which are favorable for epithelialization. The combination of NPWT (negative-pressure wound therapy) with AgNPs (silver nanoparticles) has not been widely studied.

MATERIALS AND METHODS

This study aimed to compare the outcomes of silver nanoparticle sheets with the combination of negative-pressure wound therapy and silver nanoparticle dressings. We conducted a comparative prospective study on 80 patients admitted to the Plastic Surgery Department of "Prof. Dr. Agrippa Ionescu" Emergency Clinical Hospital between 1st of January 2020 and 31st of December 2022. The study population was randomized to receive either silver nanoparticle dressings or negative-pressure wound therapy (NPWT) combined with silver nanoparticle dressings. Various parameters were monitored, including patient comorbidities and graft-related data such as defect etiology, graft integration, and graft size. Dressings were changed, and graft status was evaluated at 7, 10, and 14 days postoperatively. Additionally, baseline C-reactive protein (CRP) levels were measured before surgery and 7, 10, and 14 days postoperatively.

RESULTS

The study demonstrated an enhanced integration of skin grafts at all evaluation stages when employing NPWT combined with AgNPs, particularly evident 10 days post operation. Significant variations in graft integration were also observed based on factors such as diabetes, cardiovascular disease, graft size, or the origin of the grafted defect. Moreover, dynamic C-reactive protein monitoring showed a statistically significant decrease in CRP levels 10 days post operation among patients treated with NPWT in conjunction with silver dressing, consistent with the nearly complete integration of skin grafts at this evaluation threshold.

CONCLUSION

Several factors influence the postoperative evolution of split-skin grafts. Postoperative dressings target local factors to enhance graft integration further. Our research demonstrated that the innovative combination of NPWT-assisted dressings, complemented by a silver nanoparticle sheet, resulted in improved benefits for graft integration and the alleviation of systemic inflammation.

Mesenchymal stem cells overexpressing XIST induce macrophage M2 polarization and improve neural stem cell homeostatic microenvironment, alleviating spinal cord injury

Spinal cord injury (SCI) is a significant cause of disability worldwide, with limited treatment options. This study investigated the potential of bone marrow-derived mesenchymal stem cells (BMSCs) modified with XIST lentiviral vector to modulate macrophage polarization and affect neural stem cell (NSC) microenvironment reconstruction following SCI. Bioinformatics analysis revealed that MID1 might be crucial for BMSCs' treatment of SCI. XIST overexpression enriched Zmynd8 to the promoter region of MID1 and inhibited MID1 transcription, which promoted macrophage M2 polarization. In vitro experiments showed that BMSCs-XIST promoted NSC proliferation, migration, differentiation, and axonal growth by inducing macrophage M2 polarization, suppressing inflammation, and accelerating the re-establishment of the homeostatic microenvironment of NSCs. In vivo, animal experiments confirmed that BMSCs-XIST significantly alleviated SCI by promoting NSC differentiation and axon formation in the injured area. The study demonstrated the potential of XIST-overexpressing BMSCs for treating SCI by regulating macrophage polarization and homeostasis of the NSC microenvironment. These findings provide new insights into the development of stem cell-based therapies for SCI.

Recent advances in strategies to target the behavior of macrophages in wound healing

Chronic wounds and scar formation are widespread due to limited suitable remedies. The macrophage is a crucial regulator in wound healing, controlling the onset and termination of inflammation and regulating other processes related to wound healing. The current breakthroughs in developing new medications and drug delivery methods have enabled the accurate targeting of macrophages in oncology and rheumatic disease therapies through clinical trials. These successes have cleared the way to utilize drugs targeting macrophages in various disorders. This review thus summarizes macrophage involvement in normal and pathologic wound healing. It further details the targets available for macrophage intervention and therapeutic strategies for targeting the behavior of macrophages in tissue repair and regeneration.

Role of medicinal herbs and phytochemicals in post burn management

Burn management is a natural and distinctly programmed process involving overlapping phases of hemostasis, inflammation, proliferation and remodeling. Burn wound healing involves initiation of inflammation, re-epithelialization, granulation, neovascularization and wound contraction. Despite the availability of multiple preparations for management of burn wound, there is dire need for efficacious alternative agents. Current approaches for burn wound management include pharmaceutical agents and antibiotics. However, high cost of synthetic drugs and accelerated resistance to antibiotics is challenging for both developed and developing nations. Among alternative options, medicinal plants have been a biocompatible, safe and affordable source of preventive/curative approaches. Due to cultural acceptance and patient compliance, there has been a focus on the use of botanical drugs and phytochemicals for burn wound healing. Keeping in consideration of medicinal herbs and phytochemicals as suitable therapeutic/adjuvant agents for burn wound management, this review highlights therapeutic potential of 35 medicinal herbs and 10 phytochemicals. Among these, Elaeis guineensis, Ephedra ciliate and Terminalia avicennioides showed better burn wound healing potential with varied mechanisms such as modulation of TNF-alpha, inflammatory cytokines, nitric oxide, eicosanoids, ROS and leukocyte response. Phytochemicals (oleanolic acid, ursolic acid, kirenol) also showed promising role in burn wound management though various pathways involving such as down regulation of TNF-alpha, IL-6 and inflammatory mediators including plasma proteases and arachidonic acid metabolites. This review provides a pavement for therapeutic/adjuvant use of potential botanical drugs and novel druggable phyto-compounds to target skin burn injury with diverse mechanisms, affordability and safety profile.

Skin Inflammation with a Focus on Wound Healing

Significance: The skin is the crucial first-line barrier against foreign pathogens. Compromise of this barrier presents in the context of inflammatory skin conditions and in chronic wounds. Skin conditions arising from dysfunctional inflammatory pathways severely compromise the quality of life of patients and have a high economic impact on the U.S. health care system. The development of a thorough understanding of the mechanisms that can disrupt skin inflammation is imperative to successfully modulate this inflammation with therapies. Recent Advances: Many advances in the understanding of skin inflammation have occurred during the past decade, including the development of multiple new pharmaceuticals. Mechanical force application has been greatly advanced clinically. Bioscaffolds also promote healing, while reducing scarring. Critical Issues: Various skin inflammatory conditions provide a framework for analysis of our understanding of the phases of successful wound healing. The large burden of chronic wounds on our society continues to focus attention on the chronic inflammatory state induced in many of these skin conditions. Future Directions: Better preclinical models of disease states such as chronic wounds, coupled with enhanced diagnostic abilities of human skin, will allow a better understanding of the mechanism of action. This will lead to improved treatments with biologics and other modalities such as the strategic application of mechanical forces and scaffolds, which ultimately results in better outcomes for our patients.

Modulation of Lymphangiogenesis in Incisional Murine Diabetic Wound Healing Using Negative Pressure Wound Therapy

Objective: Despite the significant function of lymphatics in wound healing, and frequent clinical use of Negative Pressure Wound Therapy (NPWT), the effect of mechanical force application on lymphangiogenesis remains to be elucidated. We utilize a murine incisional wound healing model to assess the mechanisms of lymphangiogenesis following NPWT. Approach: Dorsal incisional skin wounds were created on diabetic mice (genetically obese leptin receptor-deficient mice [db/db]; n = 30) and covered with an occlusive dressing (Control, n = 15) or NPWT (-125 mmHg, continuous, 24 h for 7 days; NPWT, n = 15). The wounds were macroscopically assessed for 28 days. Tissue was harvested on day 10 for analysis. Qualitative functional analysis of lymphatic drainage was performed on day 28 using Evans Blue staining (n = 2). Results: NPWT increased lymphatic vessel density (40 ± 20 vs. 12 ± 6 podoplanin [PDPN]⁺ and 25 ± 9 vs. 14 ± 8 lymphatic vessel endothelial receptor 1 [LYVE-1]⁺) and vessel diameter (28 ± 9 vs. 12 ± 2 μm). Western blotting verified the upregulation of LYVE-1 with NPWT. Leukocyte presence was higher with NPWT (22% ± 3.7% vs. 9.1% ± 4.1% lymphocyte common antigen [CD45]⁺) and the leukocytes were predominately B cells clustered within vessels (8.8% ± 2.5% vs. 18% ± 3.6% B-lymphocyte antigen CD20 [CD20]⁺). Macrophage presence was lower in the NPWT group. Lymphatic drainage was increased in the NPWT group, which exhibited greater Evans Blue positivity. Innovation: The lymphangiogenic effects take place independent of macrophage infiltration, appearing to correlate with B cell presence. Conclusion: NPWT promotes lymphangiogenesis in incisional wounds, significantly increasing the lymph vessel density and diameter. This study highlights the potential of NPWT to stimulate lymphatic drainage and wound healing of surgical incisions.

Negative Pressure Wound Therapy Promotes Wound Healing by Inhibiting Inflammation in Diabetic Foot Wounds: A Role for NOD1 Receptor

Aims: Diabetic foot results in frequent amputation and quality-of-life reduction in diabetes population. These lesions are featured by a prolonged and exaggerated inflammation with a significant impairment in local bacterial invasion. Negative pressure wound therapy (NPWT) attenuates hyperinflammation in the healing of diabetic foot wounds, but the potential mechanism of NPWT down-regulated inflammatory reaction still remains elusive. This study aims to explore the inflammatory signaling involved in the effect of NPWT on diabetic ulcer. Methods: Thirty patients with diabetic foot ulceration were divided into NPWT group (treated with NPWT, n = 10), NPWT + FK565 group (treated with NPWT combined with FK565 which is NOD1 receptor ligand, n = 10) and control group (n = 10). After two weeks treatment, samples were harvested and analyzed by histochemistry for infiltration of inflammatory cells, immunofluorescence stain for NOD1, western blotting for NOD1, RIP2 (Receptor interacting protein 2), IL-1β, TAK1 (Transforming growth factor-β-activated kinase1), p65 and real time-PCR for expression of NOD1 and RIP2. Results: NPWT could notably accelerate the diabetic wound healing through alleviating inflammatory reaction. The immunofluorescence analysis results revealed that NOD1 was mainly expressed in the cytoplasm and noticeably decreased after the NPWT treatment. And NPWT obviously decreased both the mRNA and protein level of NOD1 and RIP2. Moreover, The protein expression of IL-1β, TAK1 and p65 in the NPWT-group were significant decreased. Conclusion: NPWT effectively promotes wound healing by suppressing the wound inflammation in diabetic foot, which is mediated at least in part by suppression of NOD1 receptor.

Wound Healing Impairment in Type 2 Diabetes Model of Leptin-Deficient Mice—A Mechanistic Systematic Review

Type II diabetes mellitus (T2DM) is one of the most prevalent diseases in the world, associated with diabetic foot ulcers and impaired wound healing. There is an ongoing need for interventions effective in treating these two problems. Pre-clinical studies in this field rely on adequate animal models. However, producing such a model is near-impossible given the complex and multifactorial pathogenesis of T2DM. A leptin-deficient murine model was developed in 1959 and relies on either dysfunctional leptin (ob/ob) or a leptin receptor (db/db). Though monogenic, this model has been used in hundreds of studies, including diabetic wound healing research. In this study, we systematically summarize data from over one hundred studies, which described the mechanisms underlying wound healing impairment in this model. We briefly review the wound healing dynamics, growth factors’ dysregulation, angiogenesis, inflammation, the function of leptin and insulin, the role of advanced glycation end-products, extracellular matrix abnormalities, stem cells’ dysregulation, and the role of non-coding RNAs. Some studies investigated novel chronic diabetes wound models, based on a leptin-deficient murine model, which was also described. We also discussed the interventions studied in vivo, which passed into human clinical trials. It is our hope that this review will help plan future research.

The Immune-Centric Revolution in the Diabetic Foot: Monocytes and Lymphocytes Role in Wound Healing and Tissue Regeneration-A Narrative Review

Monocytes and lymphocytes play a key role in physiologic wound healing and might be involved in the impaired mechanisms observed in diabetes. Skin wound macrophages are represented by tissue resident macrophages and infiltrating peripheral blood recruited monocytes which play a leading role during the inflammatory phase of wound repair. The impaired transition of diabetic wound macrophages from pro-inflammatory M1 phenotypes to anti-inflammatory pro-regenerative M2 phenotypes might represent a key issue for impaired diabetic wound healing. This review will focus on the role of immune system cells in normal skin and diabetic wound repair. Furthermore, it will give an insight into therapy able to immuno-modulate wound healing processes toward to a regenerative anti-inflammatory fashion. Different approaches, such as cell therapy, exosome, and dermal substitute able to promote the M1 to M2 switch and able to positively influence healing processes in chronic wounds will be discussed.

Characterization of Macrophage and Cytokine Interactions with Biomaterials Used in Negative-Pressure Wound Therapy

Macrophages are innate immune cells that help wounds heal. Here, we study the potential immunomodulatory effects of negative-pressure wound therapy (NPWT) materials on the macrophage inflammatory response. We compared the effects of two materials, Granufoam™ (GF) and Veraflo Cleanse™ (VC), on macrophage function in vitro. We find that both materials cause reduced expression of inflammatory genes, such as TNF and IL1B, in human macrophages stimulated with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFNγ). Relative to adherent glass control surfaces, VC discourages macrophage adhesion and spreading, and may potentially sequester LPS/IFNγ and cytokines that the cells produce. GF, on the other hand, was less suppressive of inflammation, supported macrophage adhesion and spreading better than VC, and sequestered lesser quantities of LPS/IFNγ in comparison to VC. The control dressing material cotton gauze (CT) was also immunosuppressive, capable of TNF-α retention and LPS/IFNγ sequestration. Our findings suggest that NPWT material interactions with cells, as well as soluble factors including cytokines and LPS, can modulate the immune response, independent of vacuum application. We have also established methodological strategies for studying NPWT materials and reveal the potential utility of cell-based in vitro studies for elucidating biological effects of NPWT materials.

Immunology of Acute and Chronic Wound Healing

Skin wounds greatly affect the global healthcare system, creating a substantial burden on the economy and society. Moreover, the situation is exacerbated by low healing rates, which in fact are overestimated in reports. Cutaneous wounds are generally classified into acute and chronic. The immune response plays an important role during acute wound healing. The activation of immune cells and factors initiate the inflammatory process, facilitate wound cleansing and promote subsequent tissue healing. However, dysregulation of the immune system during the wound healing process leads to persistent inflammation and delayed healing, which ultimately result in chronic wounds. The microenvironment of a chronic wound is characterized by high quantities of pro-inflammatory macrophages, overexpression of inflammatory mediators such as TNF-α and IL-1β, increased activity of matrix metalloproteinases and abundance of reactive oxygen species. Moreover, chronic wounds are frequently complicated by bacterial biofilms, which perpetuate the inflammatory phase. Continuous inflammation and microbial biofilms make it very difficult for the chronic wounds to heal. In this review, we discuss the role of innate and adaptive immunity in the pathogenesis of acute and chronic wounds. Furthermore, we review the latest immunomodulatory therapeutic strategies, including modifying macrophage phenotype, regulating miRNA expression and targeting pro- and anti-inflammatory factors to improve wound healing.