Nociceptive and Transcriptomic Responses in a Swine Diabetic Wound Model Treated With a Topical Angiotensin 1 Receptor Antagonist

BACKGROUND

Painful, treatment-resistant wounds are prevalent among diabetic patients and significantly affect health-related quality of life (HRQOL). Topical treatments may help alleviate pain without risk of dependence or side effects. However, there is a lack of topical wound compounds targeting pain-specific receptors. One possible target is proinflammatory angiotensin 1 receptor (AT1R), which is upregulated in diabetic skin and has been implicated in nociception.

OBJECTIVES

We investigated the effects of topical valsartan, an AT1R antagonist, on pain (nociceptive thresholds) and gene expression changes (transcriptomics) in a swine model of diabetic wounds.

METHODS

Eight wounds were surgically induced in diabetic, hyperglycemic Yucatan miniature swine ( n = 4). Topical AT1R antagonist was applied to wounds on one side and vehicle on the other side. Nocifensive testing was conducted at baseline and then weekly, beginning 7 days after wound induction. Mechanical and thermal stimuli were applied to the wound margins until a nocifensive reaction was elicited or a predetermined cutoff was reached. After 7 weeks of testing, tissue from the dorsal horn, dorsal root ganglion, and wounds were sequenced and analyzed with DESeq2. Unbiased pathway analyses using Metascape were conducted on differentially expressed genes.

RESULTS

There was no significant difference in mechanical tolerance threshold between AT1R antagonist-treated and vehicle-treated wounds ( p = .106). Thermal tolerance was significantly higher in AT1R antagonist-treated wounds compared to vehicle-treated ( p = .015). Analysis of differentially expressed genes revealed enriched pathways of interest: interleukin-18 signaling in dorsal horn laminae IV-V and sensory perception of mechanical stimulus in wound tissue.

DISCUSSION

In this study, wounds modeling diabetic ulcers were created in hyperglycemic swine and treated with a topical AT1R antagonist. AT1R-antagonist-treated wounds had a higher tolerance threshold than vehicle-treated wounds for thermal hyperalgesia, but not mechanical allodynia. Pathway analyses of differentially expressed genes revealed several pathways of interest for future pain research. Although further studies are needed to confirm the findings, this study can improve nursing care by providing information about a potential future treatment that may be used to decrease pain and improve HRQOL in patients with diabetic wounds.

Advantages of a New Low-Cost Negative Pressure Wound Therapy Using the "Turtle VAC": A Case Series

CASE

We present a clinical case and technique guide demonstrating the use and effectiveness of a novel, low-cost negative pressure wound therapy (NPWT) device to achieve soft-tissue coverage in a 34-year-old patient with failed rotational flap and Masquelet technique on infected tibial nonunion. Local debridement was executed, NPWT initiated, and treatment culminated with complete wound healing.

CONCLUSION

The "Turtle VAC" offers an effective low-cost alternative to commercially vacuum-assisted closure systems for post-traumatic wounds in low-resource setting of Haiti. Its use of available equipment makes NPWT accessible and can function as a bridge to definitive closure when primary wound closure is not possible and/or between debridement procedures.

In vivo diabetic wound healing with nanofibrous scaffolds modified with gentamicin and recombinant human epidermal growth factor

Diabetic wounds are susceptible to microbial infection. The treatment of these wounds requires a higher payload of growth factors. With this in mind, the strategy for this study was to utilize a novel payload comprising of Eudragit RL/RS 100 nanofibers carrying the bacterial inhibitor gentamicin sulfate (GS) in concert with recombinant human epidermal growth factor (rhEGF); an accelerator of wound healing. GS containing Eudragit was electrospun to yield nanofiber scaffolds, which were further modified by covalent immobilization of rhEGF to their surface. This novel fabricated nanoscaffold was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The thermal behavior of the nanoscaffold was determined using thermogravimetric analysis and differential scanning calorimetry. In the in vitro antibacterial assays, the nanoscaffolds exhibited comparable antibacterial activity to pure gentemicin powder. In vivo work using female C57/BL6 mice, the nanoscaffolds induced faster wound healing activity in dorsal wounds compared to the control. The paradigm in this study presents a robust in vivo model to enhance the applicability of drug delivery systems in wound healing applications. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 641-651, 2018.

Regulation of impaired angiogenesis in diabetic dermal wound healing by microRNA-26a

Wound healing is a physiological reparative response to injury and a well-orchestrated process that involves hemostasis, cellular migration, proliferation, angiogenesis, extracellular matrix deposition, and wound contraction and re-epithelialization. However, patients with type 2 diabetes mellitus (T2D) are frequently afflicted with impaired wound healing that progresses into chronic wounds or diabetic ulcers, and may lead to complications including limb amputation. Herein, we investigate the potential role of microRNA-26a (miR-26a) in a diabetic model of wound healing. Expression of miR-26a is rapidly induced in response to high glucose in endothelial cells (ECs). Punch skin biopsy wounding of db/db mice revealed increased expression of miR-26a (~3.5-fold) four days post-wounding compared to that of WT mice. Local administration of a miR-26a inhibitor, LNA-anti-miR-26a, induced angiogenesis (up to ~80%), increased granulation tissue thickness (by 2.5-fold) and accelerated wound closure (53% after nine days) compared to scrambled anti-miR controls in db/db mice. These effects were independent of altered M1/M2 macrophage ratios. Mechanistically, inhibition of miR-26a increased its target gene SMAD1 in ECs nine days post-wounding of diabetic mice. In addition, high glucose reduced activity of the SMAD1-3'-UTR. Diabetic dermal wounds treated with LNA-anti-miR-26a had increased expression of ID1, a downstream modulator or SMAD1, and decreased expression of the cell cycle inhibitor p27. These findings establish miR-26a as an important regulator on the progression of skin wounds of diabetic mice by specifically regulating the angiogenic response after injury, and demonstrate that neutralization of miR-26a may serve as a novel approach for therapy.

Evaluation of low-cost custom made VAC therapy compared with conventional wound dressings in the treatment of non-healing lower limb ulcers in lower socio-economic group patients of Kashmir valley

BACKGROUND

Negative-pressure wound therapy is a technique to achieve wound healing in patients with non-healing wounds of the lower limb; vacuum-assisted closure (VAC) therapy is a technique to accelerate the healing of non-healing ulcers that fail to heal on their own (primary healing) (Plast Reconstr Surg 117:193-209S, 2006). Delayed wound healing or non-healing of ulcers is a significant health problem, particularly in older adults. The efficacy of VAC dressings has been demonstrated in several randomized controlled studies, which have shown significantly faster wound healing rates compared to conventional wound therapy (Lancet 366:1704-10, 2005; J Wound Care 17:426-32, 2008). However, commercially available VAC is costly. The aim of using custom made VAC was decided by our team due to lower socio-economic status of patients taken for study who could not have afforded charges of commercially available VAC unit.

OBJECTIVE

Objective was to evaluate VAC therapy compared with conventional dressings in the treatment of non-healing lower limb ulcers in lower socio-economic patients.

METHODS

Sixty patients of lower socio-economic status aged between 40 and 70 were prospectively studied for non-healing ulcers Wagner grade 2 or 3 and randomized into 2 groups. VAC dressing was kept for over a period of 2-7 weeks. Ulcers were treated until the wound closed spontaneously, surgically or until completion of the 50-day period, whichever was earlier.

RESULTS

By seventh week, discharge disappeared in 96 % in VAC and only 54 % in conventional dressing group. Granulation tissue appeared in 100 % of patients in VAC group and only 63 % in conventional dressing group. The patients treated with VAC dressing in our study showed comparable wound reduction capabilities with an average wound size reduction of 56 % in comparison to conventional dressing group which had average wound size reduction of 29 %. Majority of wounds in VAC group got closed in 7 weeks. Patient satisfaction was excellent in the majority of patients in VAC group compared to those in conventional dressing group.

CONCLUSION

The application of VAC™ had shown good results in our study.

Predictive Role of Preventive Measures in Preventing the Progression of Diabetic Foot

Introduction:

Diabetes mellitus (DM) is one of the most common endocrine disease of modern life. Diabetic foot (DF) is the term for a foot of a patient suffering from DM with the potential risk of a number of pathological sequels, including infection, ulceration and/or destruction of deep tissue.

Goal:

To determine the importance of preventive measures to prevent the development of diabetic foot.

Results:

The gender structure of respondents categorized by the complication of DF (yes/no) was uniform. The average age was 60.15±12.2 years. Respondents without DF, 63% had 2 visits to the doctor a month, while in the group of those with DF, 39% of them had 3 visits to a doctor and 33% four or more times. Wearing comfortable shoes and foot hygiene in relation to the development of the DF are interdependent: c²=4,409; c² = 12.47 (p <0.0005). Also, recurrent foot injury, and slow healing of sores in comparison to the development of the DF are mutually dependent; c²=13,195; c²=14 (p <0.0005).

Conclusion:

We found that there is a significant statistical relationship between preventive measures and development of the DF.

Vacuum-assisted closure versus conventional dressings in the management of diabetic foot ulcers: a prospective case-control study

Objective

To compare the effectiveness of vacuum-assisted closure (VAC) versus conventional dressings in the healing of diabetic foot ulcerations (DFUs) in terms of healing rate (time to prepare the wound for closure either spontaneously or by surgery), safety, and patient satisfaction.

Methods

Randomized case–control study enrolling 56 patients, divided into two groups. Group A (patients treated with VAC) and Group B (patients treated with conventional dressings), with an equal number of patients in each group. DFUs were treated until wound closure, either spontaneously, surgically, or until completion of the 8-week period.

Results

Granulation tissue appeared in 26 (92.85%) patients by the end of Week 2 in Group A, while it appeared in 15 (53.57%) patients by that time in Group B. 100% granulation was achieved in 21 (77.78%) patients by the end of Week 5 in Group A as compared to only 10 (40%) patients by that time in Group B. Patients in Group A had fewer number of positive blood cultures, secondary amputations and were satisfied with treatment as compared to Group B.

Conclusion

VAC appears to be more effective, safe, and patient satisfactory compared to conventional dressings for the treatment of DFUs.

Low-intensity vibration improves angiogenesis and wound healing in diabetic mice

Chronic wounds represent a significant health problem, especially in diabetic patients. In the current study, we investigated a novel therapeutic approach to wound healing – whole body low-intensity vibration (LIV). LIV is anabolic for bone, by stimulating the release of growth factors, and modulating stem cell proliferation and differentiation. We hypothesized that LIV improves the delayed wound healing in diabetic mice by promoting a pro-healing wound environment. Diabetic db/db mice received excisional cutaneous wounds and were subjected to LIV (0.4 g at 45 Hz) for 30 min/d or a non-vibrated sham treatment (controls). Wound tissue was collected at 7 and 15 d post-wounding and wound healing, angiogenesis, growth factor levels and wound cell phenotypes were assessed. LIV increased angiogenesis and granulation tissue formation at day 7, and accelerated wound closure and re-epithelialization over days 7 and 15. LIV also reduced neutrophil accumulation and increased macrophage accumulation. In addition, LIV increased expression of pro-healing growth factors and chemokines (insulin-like growth factor-1, vascular endothelial growth factor and monocyte chemotactic protein-1) in wounds. Despite no evidence of a change in the phenotype of CD11b+ macrophages in wounds, LIV resulted in trends towards a less inflammatory phenotype in the CD11b− cells. Our findings indicate that LIV may exert beneficial effects on wound healing by enhancing angiogenesis and granulation tissue formation, and these changes are associated with increases in pro-angiogenic growth factors.

Macrophage stimulating agent soluble yeast β-1,3/1,6-glucan as a topical treatment of diabetic foot and leg ulcers: A randomized, double blind, placebo-controlled phase II study

AIMS/INTRODUCTION

Dysregulated inflammatory response is believed to be an important factor in the pathogenesis of several late complications of diabetes mellitus. β-Glucans are potent inducers of immune function. The present randomized, double blind, two-center, placebo-controlled study was undertaken to explore safety, tolerability and efficacy of soluble β-1,3/1,6-glucan (SBG) as a local treatment of diabetic foot ulcers.

MATERIALS AND METHODS

A total of 60 patients with type 1 or 2 diabetes and lower extremity ulcers (Wagner grade 1-2, Ankle/Brachial Index ≥0.7) received SBG or a comparator product (methylcellulose) locally three times weekly up to 12 weeks in addition to conventional management scheme. A total of 54 patients completed the study.

RESULTS

A tendency for shorter median time to complete healing in the SBG group was observed (36 vs 63 days, P = 0.130). Weekly percentage reduction in ulcer size was significantly higher in the SBG group than in the methylcellulose group between weeks 1-2, 3-4 and 5-6 (P < 0.05). The proportion of ulcers healed by week 12 was also in favor of SBG (59% vs 37%, P = 0.09), with a significantly higher healing incidence in the SBG group at week 8 (44% vs 17%, P = 0.03). SBG was safe and well tolerated. There was a clinically significant difference regarding the incidence of serious adverse events in favor of the SBG treatment.

CONCLUSIONS

Local treatment of diabetic lower extremity ulcers with β-1,3/1,6-polyglucose shows good safety results. This β-glucan preparation shows promising potential as a treatment accelerating cutaneous healing. Further studies are required to confirm this effect. This trial was registered with ClinicalTrials.gov (no. NCT00288392).

Blocking interleukin-1β induces a healing-associated wound macrophage phenotype and improves healing in type 2 diabetes

Diabetes is associated with persistent inflammation and defective tissue repair responses. The hypothesis of this study was that interleukin (IL)-1β is part of a proinflammatory positive feedback loop that sustains a persistent proinflammatory wound macrophage phenotype that contributes to impaired healing in diabetes. Macrophages isolated from wounds in diabetic humans and mice exhibited a proinflammatory phenotype, including expression and secretion of IL-1β. The diabetic wound environment appears to be sufficient to induce these inflammatory phenomena because in vitro studies demonstrated that conditioned medium of both mouse and human wounds upregulates expression of proinflammatory genes and downregulates expression of prohealing factors in cultured macrophages. Furthermore, inhibiting the IL-1β pathway using a neutralizing antibody and macrophages from IL-1 receptor knockout mice blocked the conditioned medium-induced upregulation of proinflammatory genes and downregulation of prohealing factors. Importantly, inhibiting the IL-1β pathway in wounds of diabetic mice using a neutralizing antibody induced a switch from proinflammatory to healing-associated macrophage phenotypes, increased levels of wound growth factors, and improved healing of these wounds. Our findings indicate that targeting the IL-1β pathway represents a new therapeutic approach for improving the healing of diabetic wounds.

Estimating the current and future costs of Type 1 and Type 2 diabetes in the UK, including direct health costs and indirect societal and productivity costs

AIMS

To estimate the current and future economic burdens of Type 1 and Type 2 diabetes in the UK.

METHODS

A top-down approach was used to estimate costs for 2010/2011 from aggregated data sets and literature. Prevalence and population data were used to project costs for 2035/2036. Direct health costs were estimated from data on diagnosis, lifestyle interventions, ongoing treatment and management, and complications. Indirect costs were estimated from data on mortality, sickness, presenteeism (potential loss of productivity among people who remain in work) and informal care.

RESULTS

Diabetes cost approximately £ 23.7bn in the UK in 2010/2011: £ 9.8bn in direct costs (£1bn for Type 1 diabetes and £ 8.8bn for Type 2 diabetes) and £ 13.9bn in indirect costs (£ 0.9bn and £ 13bn). In real terms, the 2035/2036 cost is estimated at £ 39.8bn: £ 16.9bn in direct costs (£ 1.8bn for Type 1 diabetes and £ 15.1bn for Type 2 diabetes) and £ 22.9bn in indirect costs (£ 2.4bn and £ 20.5bn). Sensitivity analysis applied to the direct costs produced a range of costs: between £ 7.9bn and £ 11.7bn in 2010/2011 and between £ 13.8bn and £20bn in 2035/2036. Diabetes currently accounts for approximately 10% of the total health resource expenditure and is projected to account for around 17% in 2035/2036.

CONCLUSIONS

Type 1 and Type 2 diabetes are prominent diseases in the UK and are a significant economic burden. Data differentiating between the costs of Type 1 and Type 2 diabetes are sparse. Complications related to the diseases account for a substantial proportion of the direct health costs. As prevalence increases, the cost of treating complications will grow if current care regimes are maintained.

Polymer-Based Nitric Oxide Therapies: Recent Insights for Biomedical Applications

Since the discovery of nitric oxide (NO) in the 1980s, this cellular messenger has been shown to participate in diverse biological processes such as cardiovascular homeostasis, immune response, wound healing, bone metabolism, and neurotransmission. Its beneficial effects have prompted increased research in the past two decades, with a focus on the development of materials that can locally release NO. However, significant limitations arise when applying these materials to biomedical applications. This Feature Article focuses on the development of NO-releasing and NO-generating polymeric materials (2006-2011) with emphasis on recent in vivo applications. Results are compared and discussed in terms of NO dose, release kinetics, and biological effects, in order to provide a foundation to design and evaluate new NO therapies.

Avaliação de sintomas depressivos em pessoas com diabetes mellitus e pé ulcerado

OBJETIVO: Avaliar a intensidade de sintomas de depressão nos pacientes diabéticos com úlceras no pé. MÉTODOS: Estudo exploratório, descritivo, analítico e transversal, realizado no ambulatório de feridas de um hospital público, de Sorocaba/SP. Participaram 50 pacientes com diabetes mellitus e pé ulcerado. Para mensurar a intensidade dos sintomas de depressão foi utilizado o inventário de Avaliação de Depressão de Beck. RESULTADOS: Dos 50 pacientes avaliados, 41 apresentavam algum grau de sintoma depressivo, sendo que 32 (64%) com depressão moderada, apresentando sintomas de autodepreciação, tristeza, distorção da imagem corporal e diminuição da libido. CONCLUSÃO: Pacientes diabéticos com pé ulcerado apresentaram graus variados de sintomas depressivos.