Negative-pressure wound therapy for management of chronic neuropathic noninfected diabetic foot ulcerations - short-term efficacy and long-term outcomes

The effect of negative pressure wound therapy on the outcome of diabetic foot ulcers: A meta-analysis

Negative pressure injury is one of the auxiliary methods of treating diabetes foot ulcers. It has been shown to be superior to conventional techniques in randomized controlled trials (RCTs). Nevertheless, the results of observational research are still scarce. A systematic review of RCTs and observations was carried out to evaluate the effectiveness and security of negative pressure wound therapy (NPWT) treatment for diabetes foot ulcers. Three English e-databases have been found for NPWT research. The meta-analyses of the comparative studies provided point estimates of results. Intermediate results were given as median and binary values were given in the form of odds ratios (OR). Seventeen trials, 13 RCTs and four randomized, controlled trials were found in the survey. Of these, 831 were treated with NPWT, 834 were treated with standard therapy. A total of 14 studies have been conducted to investigate the influence of NPWT on the healing of diabetic foot ulcers(DFU). In the study, NPWT was shown to speed up the healing of the wound in DFU patients(OR, 2.57; 95% CI, 1.72, 3.85 p < 0.0001). A subgroup analysis showed that NPWT was associated with an acceleration of the wound healing rate in 10 RCT trials (OR, 2.48; 95% CI, 1.58, 3.89 p < 0.001). In the four nRCT trials, NPWT was also shown to speed up the healing of the wound(OR, 2.95; 95% CI, 1.03, 8.42 p = 0.04). In 11 studies, the influence of NPWT on amputations of diabetes mellitus (DM) foot ulcers was investigated. The results showed that NPWT was associated with a reduction in amputations (OR, 0.53; 95% CI, 0.37, 0.74 p = 0.0002).In a subgroup of RCT trials, nine RCT trials showed a reduction in amputations(OR, 0.61; 95% CI, 0.43, 0.87 p = 0.007). In both nRCT trials, NPWT also showed a reduction in amputations (OR, 0.03; 95% CI, 0.00, 0.24 p = 0.001). Generally speaking, NPWT can help to heal the wound and lower the risk of amputations in people with diabetes. The subgroup analysis showed similar results for the RCT and non-RCT trials. NPWT can be used to treat diabetes foot ulcers caused by diabetes.

Evaluation of a new low-cost negative pressure wound therapy in the treatment of diabetic foot ulcers

OBJECTIVE

To investigate the effectiveness of a new and low-cost negative pressure wound therapy (LC-NPWT) in the treatment of diabetic foot ulcers (DFUs).

METHOD

In this retrospective cohort study, patients from our inpatient clinic with Wagner grade 3 DFUs were given LC-NPWT or conventional wound dressings. The primary outcome was the wound healing rates. Complete wound healing, defined as complete re-epithelialisation of the wound, was recorded during the two months of follow-up. The definition of complete epidermis of the wound was that the skin was closed (100% re-epithelialisation), with no drainage or dressing. The secondary outcomes were the number of inpatient days and surgical procedures, and outcomes after hospital discharge. The wound score from the Bates-Jensen wound assessment tool and the levels of the inflammation factors procalcitonin (PCT), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were compared between the two groups. The Kaplan-Meier survival estimate was used to examine the cumulative wound healing rate.

RESULTS

The study cohort comprised 41 patients. The two-month wound healing rate was higher in patients in the LC-NPWT group than in the control group (15/21 (71.4%) versus 8/20 (40.0%), respectively; p=0.043). At the end of the two-month follow-up period, the cumulative wound healing rate was higher in the LC-NPWT group than in the control group (p=0.032). Patients in the LC-NPWT group had fewer inpatient days (19.3±3.84 versus 25.05±4.81; p<0.001) and shorter duration of antibiotic use (32.14±3.89 days versus 36.10±5.80 days; p=0.014) than those who received conventional wound dressings. There were significant improvements in mean wound score between the LC-NPWT group and the control group (p<0.001). After one week of treatment, the blood levels of PCT (0.03±0.30ng/ml versus 0.07±0.08ng/ml; p=0.039), CRP (14.55±13.40mg/l versus 24.71±18.10mg/l; p=0.047) and ESR (42.05±29.29mm/h versus 61.65±22.42mm/h; p=0.021) were lower in patients who received LC-NPWT than those who received conventional wound dressings.

CONCLUSION

LC-NPWT is effective in the treatment of DFUs and provides a cheaper alternative for patients with DFUs that could potentially alleviate the economic distress these patients endure.

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.

Understanding the multifaceted etiopathogenesis of foot complications in individuals with diabetes

Diabetes mellitus, a chronic disease of metabolism, is characterized by a disordered production or cellular utilization of insulin. Diabetic foot disease, which comprises the spectrum of infection, ulceration, and gangrene, is one of the most severe complications of diabetes and is the most common cause of hospitalization in diabetic patients. The aim of this study is to provide an evidence-based overview of diabetic foot complications. Due to neuropathy, diabetic foot infections can occur in the form of ulcers and minor skin lesions. In patients with diabetic foot ulcers, ischemia and infection are the main causes of non-healing ulcers and amputations. Hyperglycemia compromises the immune system of individuals with diabetes, leading to persistent inflammation and delayed wound healing. In addition, the treatment of diabetic foot infections is challenging due to difficulty in accurate identification of pathogenic microorganisms and the widespread issue of antimicrobial resistance. As a further complicating factor, the warning signs and symptoms of diabetic foot problems can easily be overlooked. Issues associated with diabetic foot complications include peripheral arterial disease and osteomyelitis; accordingly, the risk of these complications in people with diabetes should be assessed annually. Although antimicrobial agents represent the mainstay of treatment for diabetic foot infections, if peripheral arterial disease is present, revascularization should be considered to prevent limb amputation. A multidisciplinary approach to the prevention, diagnosis, and treatment of diabetic patients, including those with foot ulcers, is of the utmost importance to reduce the cost of treatment and avoid major adverse consequences such as amputation.

Efficacy of Prophylactic Negative-Pressure Wound Therapy with Delayed Primary Closure for Contaminated Abdominal Wounds

Background. Prophylactic negative-pressure wound therapy (NPWT) to prevent surgical site infection (SSI) may be effective for severely contaminated wounds. We investigated the safety and efficacy of NPWT with delayed primary closure (DPC) for preventing SSI. Methods. For patients with contaminated and dirty/infected surgical wounds after an emergency laparotomy, the abdominal fascia was closed with antibacterial absorbent threads and the skin was left open. Negative pressure (−80 mmHg) was applied through the polyurethane foam, which was replaced on postoperative days 3 and 7. DPC was performed when sufficient granulation was observed. The duration and adverse events of NPWT, the development of SSI, and the postoperative hospital stay were retrospectively reviewed. Results. We analyzed the cases of patients with contaminated (n = 15) and dirty/infected wounds (n = 7). The median duration of NPWT was 7 days (range 5–11 days). NPWT was discontinued in one (4.5%) patient due to wound traction pain. SSI developed in seven patients (31.8%), with incisional SSI in one (4.5%) and organ/space SSI in six (27.3%). The median postoperative hospital stay was 17 days (range 7–91 days). There was no significant relationship between postoperative hospital stay and wound classification ( $P=0.17$ ) or type of SSI ( $P=0.07$ ). Conclusion. Prophylactic NPWT with DPC was feasible and may be particularly suitable for severely contaminated wounds, with a low incidence of incisional SSI.

Vacuum sealing drainage combined with naso-intestinal and gastric decompression tubes for the treatment of esophagogastrostomy neck fistula

OBJECTIVE

To evaluate the clinical results of the vacuum sealing drainage (VSD) combined with a naso-intestinal nutritional tube (NIT) and a gastric decompression tube (GDT) for the treatment of esophagogastrostomy neck fistula (ENF).

METHODS

From January 2018 to October 2020, twenty patients (13 men and 7 women, ages 46-72) with ENF secondary to esophagogastrostomy were treated with VSD combined with NIT and GDT. Technical and clinical success rates, the incidence of early/late complications, the time of fistula closure (TFC) and therapy-related indicators were analyzed. The Karnofsky score and Eastern Cooperative Oncology Group (ECOG) score were compared before and after triple treatment.

RESULTS

Technical and clinical success rates were 100% and 85%, respectively. Early complications occurred in 5/20 (25%) patients, and late complications occurred in 8/20 (40%) patients. The median TFC was 18 days (range 10-23). All therapy-related indicators were normalized posttreatment. The Karnofsky score and ECOG score after treatment were significantly different compared with pretreatment scores (p < 0.001).

CONCLUSION

VSD combined with NIT and GDT is a safe and effective strategy for ENF, while severe strictures warrant further research.

Autologous Stem Cell Therapy for Chronic Lower Extremity Wounds: A Meta-Analysis of Randomized Controlled Trials

Lower extremity chronic wounds (LECWs) commonly occur in patients with diabetes mellitus (DM) and peripheral arterial disease (PAD). Autologous stem cell therapy (ASCT) has emerged as a promising alternative treatment for those who suffered from LECWs. The purpose of this study was to assess the effects of ASCT on LECWs. Two authors searched three core databases, and independently identified evidence according to predefined criteria. They also individually assessed the quality of the included randomized controlled trials (RCTs), and extracted data on complete healing rate, amputation rate, and outcomes regarding peripheral circulation. The extracted data were pooled using a random-effects model due to clinical heterogeneity among the included RCTs. A subgroup analysis was further performed according to etiology, source of stem cells, follow-up time, and cell markers. A total of 28 RCTs (n = 1096) were eligible for this study. The pooled results showed that patients receiving ASCT had significantly higher complete healing rates (risk ratio (RR) = 1.67, 95% confidence interval (CI) 1.28-2.19) as compared with those without ASCT. In the CD34+ subgroup, ASCT significantly led to a higher complete healing rate (RR = 2.70, 95% CI 1.50-4.86), but there was no significant difference in the CD34- subgroup. ASCT through intramuscular injection can significantly improve wound healing in patients with LECWs caused by either DM or critical limb ischemia. Lastly, CD34+ is an important cell marker for potential wound healing. However, more extensive scale and well-designed studies are necessary to explore the details of ASCT and chronic wound healing.

Pre-Clinical Assessment of Single-Use Negative Pressure Wound Therapy During In Vivo Porcine Wound Healing

Objective: Traditional negative pressure wound therapy (tNPWT) systems can be large and cumbersome, limiting patient mobility and adversely affecting quality of life. PICO™, a no canister single-use system, offers a lightweight, portable alternative to tNPWT, with improved clinical performance. The aim of this study was to determine the potential mechanism(s) of action of single-use NPWT (sNPWT) versus tNPWT. Approach: sNPWT and tNPWT were applied to an in vivo porcine excisional wound model, following product use guidelines. Macroscopic, histological, and biochemical analyses were performed at defined healing time points to assess multiple aspects of the healing response. Results: Wounds treated with single-use negative pressure displayed greater wound closure and increased reepithelialization versus those treated with traditional negative pressure. The resulting granulation tissue was more advanced with fewer neutrophils, reduced inflammatory markers, more mature collagen, and no wound filler-associated foreign body reactions. Of note, single-use negative pressure therapy failed to induce wound edge epithelial hyperproliferation, while traditional negative pressure therapy compromised periwound skin, which remained inflamed with high transepidermal water loss; features not observed following single-use treatment. Innovation: Single-use negative pressure was identified to improve multiple aspects of healing versus traditional negative pressure treatment. Conclusion: This study provides important new insight into the differing mode of action of single-use versus traditional negative pressure and may go some way to explaining the improved clinical outcomes observed with single-use negative pressure therapy.

Consensus on the application of negative pressure wound therapy of diabetic foot wounds

Because China is becoming an aging society, the incidence of diabetes and diabetic foot have been increasing. Diabetic foot has become one of the main health-related killers due to its high disability and mortality rates. Negative pressure wound therapy (NPWT) is one of the most effective techniques for the treatment of diabetic foot wounds and great progress, both in terms of research and its clinical application, has been made in the last 20 years of its development. However, due to the complex pathogenesis and management of diabetic foot, irregular application of NPWT often leads to complications, such as infection, bleeding and necrosis, that seriously affect its treatment outcomes. In 2020, under the leadership of Burns, Trauma and Tissue Repair Committee of the Cross-Straits Medicine Exchange Association, the writing group for ‘Consensus on the application of negative pressure wound therapy of diabetic foot wounds’ was established with the participation of scholars from the specialized areas of burns, endocrinology, vascular surgery, orthopedics and wound repair. Drawing on evidence-based practice suggested by the latest clinical research, this consensus proposes the best clinical practice guidelines for the application and prognostic evaluation of NPWT for diabetic foot. The consensus aims to support the formation of standardized treatment schemes that clinicians can refer to when treating cases of diabetic foot.

Cumulative long-term recurrence of diabetic foot ulcers in two cohorts from centres in Germany and the Czech Republic

AIMS

Our aim was to comprehensively estimate the incidence of diabetic foot ulcer (DFU) recurrence and corresponding risk factors in two cohorts.

METHODS

Prospective data from patients with active DFU from two diabetes centres in Germany (GER, n = 222) and the Czech Republic (CZ, n = 99) were analysed. Crude cumulative incidences were obtained. Additionally, time to recurrence and risk factors were investigated using multivariate Cox models.

RESULTS

69%(154) of patients in GER and 70%(69) in CZ experienced at least one DFU recurrence; 25%(56) in DEU and 15%(15) in CZ died; 5%(11) and 9%(9) were lost to follow-up. The crude cumulative incidence in the first year was 28% in GER and 25% in CZ; 68%/70% within ten years, and 69%/70% in 15 years. In GER, renal replacement therapy was associated with shorter time to recurrence (HR = 3.71, 95%CI:1.26-10.87); no history of DFU before the index lesion with longer time to recurrence (HR = 0.62, 0.42-0.92). In CZ, type 2 diabetes (HR = 2.57, 1.18-5.62) and index ulcer treatment by minor amputation (HR = 2.11, 1.03-4.33) were associated with shorter time to recurrence.

CONCLUSIONS

Cumulative DFU recurrence was approximately 70% in 15 years in both cohorts. We found a significantly higher risk of future recurrence in patients having a consecutive ulcer compared with the first ever ulcer.

Growth Promoting Effect of Vacuum Sealing Drainage in the Healing Processes of Diabetic Foot Ulcers

Aim

To explore the growth-promoting effect of vacuum sealing drainage (VSD) during the healing processes of diabetic foot ulcers (DFUs).

Methods

From November 2018 to December 2019, 38 patients with unilateral DFUs were enrolled in this retrospective study. All patients were divided into two groups according to the use of VSD or not: the VSD group (n=20) and the control group (n=18). The following parameters were used to evaluate the healing process: changes in the mean areas of the ulcers; healing rate (HR); epithelial hyperplasia and angiogenesis as determined by hematoxylin-eosin staining (HE staining); and expression of CD34, CD68 and VEGF as assessed through immunohistochemistry. Perioperative side effects and complications were also recorded.

Results

All patients received follow-up and eventually healed. The mean area of wounds was reduced in the VSD group compared to the control group (1.75±0.64 cm² vs 0.88±0.54 cm², P=0.031). The mean HR of the ulcers in the VSD group was significantly higher than that in the control group (35.23±2.87% vs 28.78±1.09%, P=0.017). HE staining showed that the amount of epithelial hyperplasia and angiogenesis increased significantly after VSD, and the immunohistochemistry results showed that the expression of CD34, CD68 and VEGF increased significantly in the VSD group.

Conclusion

VSD could significantly accelerate the wound healing process, probably by enhancing the inflammatory response and promoting granulation and angiogenesis in DFUs.

An update on potential biomarkers for diagnosing diabetic foot ulcer at early stage

As one of major chronic complications of diabetes, diabetic foot ulcer (DFU) is the main cause of disability and death. The clinical diagnosis and prognosis of DFU is inadequate. For clinicians, if the risk stratification of DFU can be obtained earlier in diabetic patients, the hospitalization, disability and mortality rate will be reduced. In addition to the inflammatory biomarkers that have been widely concerned and used, e.g., procalcitonin, pentraxin-3, C-reactive protein (CRP), interleukins (ILs), and tumor necrosis factor-α (TNF-α), etc., a more comprehensive prediction of the risk and severity of DFU is needed to reflect new biomarkers for therapeutic intervention effects. Along with the development of systems biology technology, genomics, proteomics, metabolomics and microbiome have been used in the studies on DFU for better understanding of the disease. In this review, new biomarkers that are expected to assist in the accurate diagnosis and risk stratification of DFU will be discussed and summarized in detail.

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

AIMS

Negative pressure wound therapy (NPWT) is commonly used in diabetic foot ulceration (DFU). The molecular mechanisms of NPWT action, particularly outside of the wound site, have not been described. We assessed NPWT's effect on circulating miRNA expression levels in type 2 diabetes (T2DM) patients with DFU.

METHODS

We examined 34 T2DM patients treated with either NPWT (n = 24) or standard therapy (ST, n = 10). The group assignment was based on clinical criteria and local practice. Next-generation sequencing-based microRNA expression was determined on the patient's plasma collected before therapy and after 8 days.

RESULTS

NPWT patients were similar to the ST group in terms of age, BMI, and HbA1c level; however, they differed by mean wound area (12.6 cm² vs. 1.1 cm² p = 0.0005). First, we analyzed the change of miRNA after NPWT or ST and observed an upregulation of let-7f-2 only in the NPWT group. Then, we analyzed the differential expression between NPWT and ST groups, looking at possible wound size effects. We found 12 differentially expressed miRNAs in pre-treatment comparison, including let-7f-2, while in post-treatment analysis we identified 28 miRNAs. The pathway enrichment analysis suggests that identified miRNAs may be involved in wound healing, particularly through angiogenesis.

CONCLUSION

We found initial evidence that NPWT in T2DM patients with DFU affects miRNA expression in plasma. Additionally, some differences in plasma miRNA expression may be related to wound size.

NPWT in diabetic foot wounds-a systematic review and meta-analysis of observational studies

PURPOSE

Negative-pressure wound therapy (NPWT) is an adjunct modality in diabetic foot ulcerations (DFUs). Randomized controlled trials (RCTs) have shown its advantage over standard approaches; however, data from observational studies remain scarce.We performed a systematic review of observational non-RCTs evaluating NPWT efficacy and safety in patients with DFU.

METHODS

Electronic databases were searched for observational studies involving NPWT. The results of single-arm studies were presented as percentages of patients with the outcome of interest. A meta-analysis of comparative studies provided point estimates of outcomes. Continuous outcomes were reported as either weighted or standardized mean differences and dichotomous data as relative risks (RR).

RESULTS

The search identified 16 relevant observational studies, 12 single-arm, and 4 comparative, reporting on a total of 18,449 patients with DFU, of whom 1882 were managed with NPWT. In the NPWT-treated patients, ulcers were larger (average size range 6.6-27.9 cm²), as compared with controls (≤3 cm²). The pooled results showed healing and major amputation in 51% and 5% of NPWT patients, respectively. The meta-analysis of comparative studies revealed lower risk of major amputation [RR = 0.23 (0.07; 0.80)] in NPWT-treated patients. The pooled results for healing rate and risk of any amputation were inconclusive due to large between-study heterogeneity. Overall, 6 deaths out of 158 patients were reported, none of them related to NPWT. Serious adverse events occurred in 6% of patients on NPWT.

CONCLUSIONS

This systematic review of observational studies provided supportive evidence that NWPT is an efficient and safe adjunct treatment in the management of DFUs.

Effectiveness of interventions to enhance healing of chronic foot ulcers in diabetes: a systematic review

The management of diabetic foot ulcers (DFU) remains a challenge, and there is continuing uncertainty concerning optimal approaches to wound healing. The International Working Group of the Diabetic Foot (IWGDF) working group on wound healing has previously published systematic reviews of the evidence in 2008, 2012 and 2016 to inform protocols for routine care and to highlight areas which should be considered for further study. The working group has now updated this review by considering papers on the interventions to improve the healing of DFU's published between June 2014 and August 2018. Methodological quality of selected studies was independently assessed by a minimum of two reviewers using the recently published 21-point questionnaire as recommended by IWGDF/European Wound Management Association, as well as the previously incorporated Scottish Intercollegiate Guidelines Network criteria. Of the 2275 papers identified, 97 were finally selected for grading following full text review. Overall, there has been an improvement in study design and a significant rise in the number of published studies. While previous systematic reviews did not find any evidence to justify the use of newer therapies, except for negative pressure wound therapy in post-surgical wounds, in this review we found additional evidence to support some interventions including a sucrose-octasulfate dressing, the combined leucocyte, fibrin and platelet patch as well as topical application of some placental membrane products, all when used in addition to usual best care. Nonetheless, the assessment and comparison of published trials remains difficult with marked clinical heterogeneity between studies: in patient selection, study duration, standard of usual care provision and the timing and description of the clinical endpoints.

Limb Salvage and Prevention of Ulcer Recurrence in a Chronic Refractory Diabetic Foot Osteomyelitis

Biomechanical changes caused by structural foot deformities predispose patients to plantar ulceration. Plantar ulcer recurrence often leads to osteomyelitis, which is more commonly observed in patients with diabetes. Once the infection of diabetic foot ulcer (DFU) spreads and is complicated by osteomyelitis, treatment becomes more complicated and difficult. Osteomyelitis treatment remains challenging because of low drug concentration within the tissue caused by poor circulation and inadequate localized nutrition. Moreover, tissues around plantar ulcers are fewer and are thin, making the formation of granulation tissues difficult due to elevated plantar pressure. Furthermore, the skin around the wound is excessively keratinized, and the epidermis is hard to regenerate. Meanwhile, skin grafting at that site is often not successful due to poor blood circulation. Therefore, it is technically challenging to manage diabetic pressure plantar ulcer with osteomyelitis and prevent its recurrence. Here, we present a case of chronic DFU complicated by osteomyelitis due to foot deformity. The ulcer was successfully healed using advanced wound repair technology comprising of surgical bone resection, vancomycin-loaded bone cement implant, negative-pressure wound therapy, and autologous platelet-rich gel. Subsequently, preventive foot care with custom-made offloading footwear was prescribed. The plantar ulcer did not recur and improvement in biomechanical parameters was observed after the intervention. This case represents an effective and comprehensive management strategy for limb salvage and prevention in patients with complicated foot conditions.

DNA methylation analysis of negative pressure therapy effect in diabetic foot ulcers

OBJECTIVE

Negative pressure wound therapy (NPWT) has been used to treat diabetic foot ulcerations (DFUs). Its action on the molecular level, however, is only partially understood. Some earlier data suggested NPWT may be mediated through modification of local gene expression. As methylation is a key epigenetic regulatory mechanism of gene expression, we assessed the effect of NPWT on its profile in patients with type 2 diabetes (T2DM) and neuropathic non-infected DFUs.

METHODS

Of 36 included patients, 23 were assigned to NPWT and 13 to standard therapy. Due to ethical concerns, the assignment was non-randomized and based on wound characteristics. Tissue samples were obtained before and 8 ± 1 days after therapy initiation. DNA methylation patterns were checked by Illumina Methylation EPIC kit.

RESULTS

In terms of clinical characteristics, the groups presented typical features of T2DM; however, the NPWT group had significantly greater wound area: 16.8 cm2 vs 1.4 cm2 (P = 0.0003). Initially only one region at chromosome 5 was differentially methylated. After treatment, 57 differentially methylated genes were found, mainly located on chromosomes 6 (chr6p21) and 20 (chr20p13); they were associated with DNA repair and autocrine signaling via retinoic acid receptor. We performed differential analyses pre treatment and post treatment. The analysis revealed 426 differentially methylated regions in the NPWT group, but none in the control group. The enrichment analysis showed 11 processes significantly associated with NPWT, of which 4 were linked with complement system activation. All but one were hypermethylated after NPWT.

CONCLUSION

The NPWT effect on DFUs may be mediated through epigenetic changes resulting in the inhibition of complement system activation.

Negative pressure wound therapy use in diabetic foot syndrome-from mechanisms of action to clinical practice

BACKGROUND

Diabetes and its complications constitute a rising medical challenge. Special attention should be given to diabetic foot syndrome (DFS) due to its high rate of associated amputation and mortality. Negative pressure wound therapy (NPWT) is a frequently used supportive modality in a diabetic foot with ulcerations (DFUs).

DESIGN

Here, we reviewed the current knowledge concerning the tissue and molecular mechanisms of NPWT action with an emphasis on diabetes research followed by a summary of clinical DFU studies and practice guidelines.

RESULTS

Negative pressure wound therapy action results in two types of tissue deformations-macrodeformation, such as wound contraction, and microdeformation occurring at microscopic level. Both of them stimulate a wound healing cascade including tissue granulation promotion, vessel proliferation, neoangiogenesis, epithelialization and excess extracellular fluid removal. On the molecular level, NPWT results in an alteration towards more pro-angiogenic and anti-inflammatory conditions. It increases expression of several key growth factors, including vascular endothelial growth factor and fibroblast growth factor 2, while expression of inflammatory cytokinesis reduced. The NPWT application also alters the presence and function of matrix metalloproteinases. Clinical studies in DFU patients showed a superiority of NPWT over standard therapy in terms of efficacy outcomes, primarily wound healing and amputation rate, without a rise in adverse events. International guidelines point to NPWT as an important adjuvant therapy in DFU whose use is expected to increase.

CONCLUSIONS

This current knowledge improves our understanding of NPWT action and its tailoring for application in diabetic patients. It may inform the development of new treatments for DFU.

Efficacy and Safety of Low-Frequency, Noncontact Airborne Ultrasound Therapy (Glybetac) For Neuropathic Diabetic Foot Ulcers: A Randomized, Double-Blind, Sham-Control Study

The diabetic foot ulcer (DFU) healing rates remain dismally low. Therefore, many adjunctive therapies have been evaluated including ultrasound therapy. The prior studies with noncontact, low-frequency ultrasound were retrospective, single arm, unblinded, or with historical controls. The aim of the present study was to compare the efficacy of noncontact, low-frequency airborne ultrasound (Glybetac) therapy with sham therapy added to standard treatment in patients with neuropathic, clinically infected, or noninfected DFU (wound size >2 cm²), Wagner grades 2 and 3. Patients received ultrasound or sham therapy for 28 days dosed daily for first 6 days followed by twice a week for next 3 weeks along with standard of care. The primary outcome was percentage of patients with at least >50% decrease in wound area at 4 week of intervention. Fifty-eight patients completed the study protocol. The duration of wound was 15.8 ± 11.2 weeks and 12.1 ± 10.9 weeks and wound area of 11.3 ± 8.2 cm² and 14.8 ± 13.8 cm² ( P = .507) in the ultrasound and sham groups, respectively. A >50% reduction in wound area was observed in 97.1% and 73.1% subjects ( P = .042) in ultrasound and sham groups, respectively. Wound contraction was faster in the first 2 weeks with ultrasound therapy, 5.3 cm², compared with 3.0 cm² ( P = .025) with sham treatment. Overall, wound area reduction of 69.4 ± 23.2% and 59.6 ± 24.9% ( P = .126) was observed at 4 weeks in the ultrasound and sham groups, respectively. We conclude that the airborne low-frequency ultrasound therapy improves and hastens the healing of chronic neuropathic DFU when combined with standard wound care.