Negative pressure wound therapy affects circulating plasma microRNAs in patients with diabetic foot ulceration

MicroRNA Expression in Chronic Venous Leg Ulcers and Implications for Wound Healing: A Scoping Review

Purpose: Chronic venous leg ulcers (CVLUs) comprise the majority of lower-extremity wounds, yet their pathophysiology is not fully understood. While research has shown that microRNAs are an important component of wound inflammation, few have explored the role of microRNAs (miRNAs) in the healing of CVLUs. This scoping review examines miRNAs in CVLUs and the association with wound healing. Methods: In December 2023, we searched MEDLINE/PubMed, Embase, Scopus, and CINAHL for studies published in 2013-2023 examining miRNAs in CVLU healing. Results: Six studies met inclusion criteria. MicroRNAs were extracted from various specimens including serum, skin biopsy samples, and adipose tissue-derived mesenchymal cells from individuals with CVLUs. Overexpression of miR-221, miR-222, miR-92a, and miR-301a-3p hindered angiogenesis, while overexpression of miR-296, miR-126, miR-378, and miR-210 facilitated angiogenesis. Overexpression of miR-34a/c, miR-301a-3p, miR-450-5p, miR-424-5p, miR-516-5p, and miR-7704 increased local inflammatory responses and inhibited keratinocytes proliferation, impairing healing, while overexpression of miR-19a/b and miR-20 downregulated keratinocytes' inflammatory response, promoting healing. Downregulation of miR-205, miR-96-5p, and miR-218-5p enhanced cellular proliferation and promoted wound healing. Downregulation of miR-17-92 was linked with impaired healing. Discussion: MicroRNAs play a role in regulating angiogenesis, inflammatory responses, and cell migration in chronic-wound healing. However, studies of miRNAs in CVLUs are limited and lack a standardized approach to measurement and quantification. Further research is warranted to elucidate the mechanisms underlying microRNA involvement in CVLU healing to better understand the pathophysiology and for the future development of targeted therapies.

Negative pressure wound therapy promotes wound healing by down-regulating miR-155 expression in granulation tissue of diabetic foot ulcers

Our study aims to investigate the effect of negative pressure wound therapy (NPWT) on microRNA-155 (miR-155) in the granulation tissue of patients suffering from diabetic foot ulcers (DFUs) and its correlation with wound healing. A total of sixty patients diagnosed with DFUs were randomly assigned to either the NPWT group (n = 40) or the Non-NPWT group (n = 20) in a 2:1 ratio. After debridement, the NPWT group received NPWT treatment for one week, while the Non-NPWT group underwent routine dressing therapy. The expression of miR-155 in DFU granulation tissues was evaluated by qRT-PCR before and after treatment for one week. Following termination, wound healing rates were assessed in the NPWT group, and the correlation between variations in miR-155 expression (ΔmiR-155) and wound healing was analyzed pre and post NPWT treatment. In vitro experiments were conducted to investigate the effects of negative pressure on variations of miR-155 expression, as well as proliferation, migration, and apoptosis in normal human dermal fibroblasts (NHDFs). The NPWT group showed a decrease in miR-155 expression in wound granulation tissue compared with pre-treatment [4.12 (1.22, 14.85) vs. 6.83 (2.15, 15.72), P < 0.05]. Conversely, there was no statistically significant difference in miR-155 expression in wound granulation tissue between pre-treatment and post-treatment in the Non-NPWT group (P > 0.05). However, analysis revealed a positive correlation between ΔmiR-155 and wound healing rate after 4 weeks in the NPWT group (χ2 = 4.829, P = 0.028). The in vitro experiments showed a significant decrease in miR-155 expression in NHDFs under negative pressure measured at -125 mmHg (P < 0.05). This reduction in miR-155 expression, in turn, enhanced the proliferation and migration ability while decreasing the apoptosis rate of NHDFs by targeting the upregulation of fibroblast growth factor 7 (FGF7) gene expression (P < 0.05). It is concluded that NPWT promotes DFU healing by reducing the expression of miR-155 in granulation tissue and the efficacy of NPWT correlated with altered miR-155 expression in wound tissue.

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.

Molecular mechanisms of action of negative pressure wound therapy: a systematic review

Negative pressure wound therapy (NPWT) has significantly advanced wound care and continues to find new applications. Its effects at a molecular level however, remain a subject of debate. The aim of this systematic review is to summarize the current evidence regarding the molecular mechanisms of action of NPWT. Medline, Embase, EBSCO databases and clinical trial registries were searched from inception to January 2023. Clinical studies, animal models or in-vitro studies that quantitatively or semi-quantitatively evaluated the influence of NPWT on growth factors, cytokine or gene-expression in the circulation or wound-bed were included. Risk of Bias assessment was performed using the RoBANS tool for non-randomized studies, the COCHRANE's Risk of Bias 2(ROB-2) tool for randomized clinical studies, OHAT tool for in-vitro studies or the SYRCLE tool for animal model studies. A descriptive summary was collated and the aggregated data is presented as a narrative synthesis. This review included 19 clinical studies, 11 animal studies and 3 in-vitro studies. The effects of NPWT on 43 biomarkers and 17 gene expressions were studied across included studies. NPWT stimulates modulation of numerous local and circulating cytokines and growth factor expressions to promote an anti-inflammatory profile. This is most likely achieved by downregulation of TNFα, upregulation of VEGF, TGF-β and fibronectin.

Regulation of NcRNA-protein binding in diabetic foot

Non-coding RNA (ncRNA) is a special type of RNA transcript that makes up more than 90 % of the human genome. Although ncRNA typically does not encode proteins, it indirectly controls a wide range of biological processes, including cellular metabolism, development, proliferation, transcription, and post-transcriptional modification. NcRNAs include small interfering RNA (siRNA), PIWI-interacting RNA (piRNA), tRNA-derived small RNA (tsRNA), etc. The most researched of these are miRNA, lncRNA, and circRNA, which are crucial regulators in the onset of diabetes and the development of associated consequences. The ncRNAs indicated above are linked to numerous diabetes problems by binding proteins, including diabetic foot (DF), diabetic nephropathy, diabetic cardiomyopathy, and diabetic peripheral neuropathy. According to recent studies, Mir-146a can control the AKAP12 axis to promote the proliferation and migration of diabetic foot ulcer (DFU) cells, while lncRNA GAS5 can activate HIF1A/VEGF pathway by binding to TAF15 to promote DFU wound healing. However, there are still many unanswered questions about the mechanism of action of ncRNAs. In this study, we explored the mechanism and new progress of ncRNA-protein binding in DF, which can provide help and guidance for the application of ncRNA in the early diagnosis and potential targeted intervention of DFU.

Negative pressure promotes macrophage M1 polarization after Mycobacterium tuberculosis infection via the lncRNA XIST/microRNA-125b-5p/A20/NF-κB axis

Experiments have demonstrated the regulation of long noncoding RNA (lncRNA) in tuberculosis (TB), and negative pressure treatment has been associated with the alleviation of TB. Here, we investigated the interaction of negative pressure and the lncRNA X-inactive specific transcript (XIST) in modulating Mycobacterium tuberculosis (MTB) infection. Initially, we established an in vitro cell model of MTB infection and an in vivo mouse model of MTB infection, followed by treatment with negative pressure. Then, we examined the expression of XIST, followed by analysis of the downstream miRNA of XIST. XIST was overexpressed or underexpressed through cell transfection to examine its effects on macrophage polarization via the miR-125b-5p/A2 axis. The MTB models were characterized by upregulated XIST and downregulated miR-125b-5p. XIST bound to miR-125b-5p, leading to its downregulation, and thus causing higher MTB survival in an ESAT-6-dependent manner. Additionally, negative pressure treatment decreased MTB-driven XIST expression through downregulation of A20 (an NF-κB repressor) via miR-125b-5 expression, promoting the M1 polarization program in macrophages through activation of the NF-κB pathway. In summary, negative pressure treatment after MTB infection can promote the polarization of macrophages to the proinflammatory M1 phenotype by regulating the XIST/miR-125b-5p/A20/NF-κB axis.

Novel therapeutic targets for diabetes-related wounds or ulcers: an update on preclinical and clinical research

INTRODUCTION

Diabetes-related wounds, particularly diabetes-related foot ulcers, are mainly caused by lack of foot sensation and high plantar tissue stress secondary to peripheral neuropathy, ischemia secondary to peripheral artery disease, and dysfunctional wound healing. Current management of diabetes-related wounds involves the offloading of high foot pressures and the treatment of ischemia through revascularization. Despite these treatments, the global burden of diabetes-related wounds is growing, and thus, novel therapies are needed. The normal wound healing process is a coordinated remodeling process orchestrated by fibroblasts, endothelial cells, phagocytes, and platelets, controlled by an array of growth factors. In diabetes-related wounds, these coordinated processes are dysfunctional. The past animal model and human research suggest that prolonged wound inflammation, failure to adequately correct ischemia, and impaired wound maturation are key therapeutic targets to improve diabetes-related wound healing.

AREAS COVERED

This review summarizes recent preclinical and clinical research on novel diabetes-related wound treatments. Animal models of diabetes-related wounds and recent studies testing novel therapeutic agents in these models are described. Findings from clinical trials are also discussed. Finally, challenges to identifying and implementing novel therapies are described.

EXPERT OPINION

Given the growing volume of promising drug therapies currently under investigation, it is expected within the next decade, that diabetes-related wound treatment will be transformed.

Downregulation of hsa-miR-203 in peripheral blood and wound margin tissue by negative pressure wound therapy contributes to wound healing of diabetic foot ulcers

Negative pressure wound therapy (NPWT) has been widely used in the treatment of chronic wounds, including diabetic foot ulcers (DFU) as the severe manifestation of diabetic foot. Hsa-miR-203 is proven to be correlated with the severity of DFU. To investigate whether NPWT influences hsa-miR-203 levels in persons with DFU, we detected hsa-miR-203 levels in peripheral plasma and wound margin tissue from the following patients: type 2 diabetic (T2D) patients with DFU (DFU group), T2D patients without DFU (NDFU group), patients with chronic skin ulcer and normal glucose tolerance (SUC group), and healthy volunteers with normal glucose tolerance (NC group). All patients in SUC group received NPWT. As contrast, some of patients in DFU group received NPWT (NPWT group) while others chose routine dressing therapy (non-NPWT group). In vitro experiments were also performed to determine influences of negative pressure on cell proliferation and migration of HaCaT cells (human keratinocytes). Results showed that before NPWT, levels of hsa-miR-203 in peripheral plasma (P-miR-203) and wound margin tissue (T-miR-203) of DFU group were obviously increased compared to SUC group while expression of P-miR-203 decreased in NDFU group compared with NC group. After NPWT, levels of P-miR-203 and T-miR-203 in DFU and SUC group were significantly lower than before. Changes of P-miR-203 and T-miR-203 after NPWT were positively correlated with 4-week ulcer healing rate in NPWT and SUC group. In vitro, negative pressure lowered the expression of hsa-miR-203, enhancing cell proliferation and migration in HaCaT cells via up-regulation of p63 protein. Meanwhile, the effects of negative pressure on cells were remarkable reduced by high-glucose intervention. Our study suggests that NPWT promotes DFU healing by reducing the expression of hsa-miR-203 in peripheral blood and wound tissue. The changes of hsa-miR-203 in peripheral blood and wound tissue may be related to the therapeutic effect of NPWT.

Microplasma Treatment versus Negative Pressure Therapy for Promoting Wound Healing in Diabetic Mice

The delayed healing response of diabetic wounds is a major challenge for treatment. Negative pressure wound therapy (NPWT) has been widely used to treat chronic wounds. However, it usually requires a long treatment time and results in directional growth of wound healing skin tissue. We investigated whether nonthermal microplasma (MP) treatment can promote the healing of skin wounds in diabetic mice. Splint excision wounds were created on diabetic mice, and various wound healing parameters were compared among MP treatment, NPWT, and control groups. Quantitative analysis of the re-epithelialization percentage by detecting Ki67 and DSG1 expression in the extending epidermal tongue (EET) of the wound area and the epidermal proliferation index (EPI) was subsequently performed. Both treatments promoted wound healing by enhancing wound closure kinetics and wound bed blood flow; this was confirmed through histological analysis and optical coherence tomography. Both treatments also increased Ki67 and DSG1 expression in the EET of the wound area and the EPI to enhance re-epithelialization. Increased Smad2/3/4 mRNA expression was observed in the epidermis layer of wounds, particularly after MP treatment. The results suggest that the Smad-dependent transforming growth factor β signaling contributes to the enhancement of re-epithelialization after MP treatment with an appropriate exposure time. Overall, a short-term MP treatment (applied for 30 s twice a day) demonstrated comparable or better efficacy to conventional NPWT (applied for 4 h once a day) in promoting wound healing in diabetic mice. Thus, MP treatment exhibits promise for treating diabetic wounds clinically.

Treatment of diabetic foot ulcers

Background: Diabetic foot ulcers (DFUs), a risk factor for infection, remain a difficult clinical complication. Infected DFUs may be associated with lower extremity amputation. To achieve wound healing and avoid amputation, an assortment of dressing materials and negative pressure wound therapy (NPWT) have been used on soft tissue injuries resulting from infected DFUs. A great deal of interest about the use of dressing materials and NPWT in the treatment of DFUs has arisen. However, there have only been a few high-quality studies regarding this topic.Current Concepts: Ideal dressing materials should satisfy certain conditions to alleviate symptoms of DFU infection and enhance the wound healing process. A single dressing material cannot fulfill all of these requirements. Based on clinical trials, different dressing materials must be chosen according to the status of the individual wound environment, including the amount of exudate, degree of pain, severity of the infection, and cost-effectiveness. However, there has been no clear evidence that advanced wound dressing materials are superior to basic dressing materials in wound healing. Recently, NPWT has been used to cover the soft tissue defects of infected DFU with granulation tissue. NPWT may contribute to changing growth factor expression, micro- and macro-deformation, vascular flow, amount of exudate, and the bacterial environment in DFU, despite the unclear mechanism of its role in wound repair.Discussion and Conclusion: Further research to obtain high-quality evidence regarding the benefits of using dressing materials and NPWT is needed. The optimal protocol for DFU and cost-effectiveness should be included in these future studies.

Application of a simple skin stretching system and negative pressure wound therapy in repair of complex diabetic foot wounds

The management of complex diabetic foot wounds with large skin defects poses a challenge for surgeons. We presented a simple skin stretching system and negative pressure wound therapy for the repair of complex diabetic foot wounds to examine the effectiveness and safety.

A total of 16 patients with diabetic foot ulcers were retrospectively reviewed between January 2015 and October 2020. All patients underwent the treatment by 3 stages. In stage 2, these difficult-to-close wounds of diabetes foot were residual. This method was applied to the wounds with a median defect size of 20.42 cm² (range, 4.71–66.76 cm²).

The median time for closure of complex diabetic foot wounds was 14 days ranging from 8 to 19 days. With respect to the absolute rates of reduction, it was observed with a median of 1.86 cm²/day, ranging from 0.29 cm²/day to 8.35 cm²/day. In accordance with the localization of the defect, the patients were divided into 3 groups: side of the foot (37.5%), dorsum of the foot (50.0%), and others (12.5%). There was no statistical difference between side of the foot and dorsum of the foot in terms of the median defect size with P = 0.069 (Kruskal–Wallis test). Otherwise, there were statistically significant differences regarding the median time and the median absolute rates (P < 0.05; Kruskal–Wallis test). No severe complications were encountered in this study.

In summary, our results show that application of the simple skin stretching system and NPWT is an effective and safe approach to complex diabetic foot wounds. Nevertheless, more attention should be paid to the appropriate patient selection and intraoperative judgment to ensure wound closure and avoid undue complications.

Enhanced Expression of miR-34c in Peripheral Plasma Associated with Diabetic Foot Ulcer in Type 2 Diabetes Patients

OBJECTIVE

To explore the correlation between the expression of miR-34c in peripheral blood of patients with type 2 diabetes mellitus (T2DM) and the onset of diabetic foot ulcer (DFU) and diabetic foot osteomyelitis (DFO).

METHODS

Sixty newly diagnosed patients with T2DM without DFU (T2DM group), 112 T2DM patients with DFU (DFU group) and 60 controls with normal glucose tolerance (NC group). The DFU group patients were subdivided into DFO (n=64) and NDFO (n=48) groups. Quantitative real-time PCR (qRT-PCR) method was used to determine miR-34c expression levels in the peripheral blood of subjects to analyze the clinical characteristics of DFU and DFO risk factors.

RESULTS

MiR-34c expression level in the T2DM group was marked higher than the NC group [2.99 (1.45-6.22) vs 1.01 (0.89-1.52)] (P < 0.05). However, the expression level of miR-34c in the DFU group was significantly higher than the T2DM group [9.65 (6.15-18.63) vs 2.99 (1.45-6.22)] (P < 0.01). Compared with the NDFO group, the expression level of miR-34c in the DFO group was also obviously increased [13.46 (8.89-19.11) vs 6.02 (5.93-14.72)] (P < 0.01). The expression level of miR-34c in DFU patients was positively correlated with the amputation rate of foot ulcers (P=0.030) and was negatively correlated with the healing rate of foot ulcers after eight weeks (P=0.025). Multifactorial logistic regression analysis showed that increased expression of miR-34c was an independent risk factor for DFU and DFO (OR_DFU=3.47, OR_DFO=4.25, P < 0.01). Meanwhile, the ROC curve analysis indicated that the AUC of miR-34c for the diagnosis of DFU and DFO was 0.803 and 0.904, the optimum sensitivity being was 100% and 98.7%, the optimum specificity was 98.4% and 98.4%, respectively.

CONCLUSION

The increased expression of miR-34c in peripheral blood of T2DM patients is closely related to the occurrence, development and prognosis of DFU and DFO.