New horizons in the understanding of the causes and management of diabetic foot disease: report from the 2017 Diabetes UK Annual Professional Conference Symposium

An Observational Clinical Trial Examining the Effect of Topical Oxygen Therapy (Natrox™) on the Rates of Healing of Chronic DiAbetic Foot Ulcers (OTONAL Trial)

Natrox™ topical oxygen therapy (TOT) (Inotec AMD Ltd, Cambridgeshire, UK) employs a small battery-powered "oxygen generator" to concentrate atmospheric oxygen and feeds pure, moist, oxygen through a fine, soft tube to a dressing-like "oxygen distribution system", which is placed over the wound and is held in place by a conventional dressing. The aim was to determine the effectiveness of Natrox™ for non-healing diabetic foot ulcers (DFU) over a 3-month period.Longitudinal, single-arm, open prospective registry study using 12 weeks of TOT using a 4 week run-in period. 20 patients recruited to OTONAL had chronic DFU greater than 3 months duration or minor amputation sites with less than 50% healing in 4 weeks.There were 13 (65%) males and the mean age was 65.7 (±11.6) years. The mean glycated haemoglobin (HbA1c) was 6.9 (±1.3) mmol mol-1 and mean wound duration before TOT was 114 (±79.1) days. 18/20 (90.0%) patients had concomitant lower limb revascularization angioplasty for chronic limb threatening ischaemia. The mean size of the foot ulcer at baseline was 11.3 ± 14.8 cm2 and mean transcutaneous oxygen measurement value was 34.1 (±19.6) mm Hg. Wound closure of >75% was observed in 14/20 (70.0%) patients. There was a 91.3% (±14.9%) wound area reduction by 3 months (P = .001) and mean time for 100% closure was 77.6 ± 32.5 days. Mean pain scores reduced from 2.4 (±1.8) at baseline to .5 (±1.0) at 3 months (P = .008). All patients were very satisfied using the ambulatory device. Use of TOT in chronic diabetic foot wounds stimulates a healing state, underpinning the concept that oxygen plays a central role in wound healing. Our results are more compelling if you consider they started with relatively large-sized DFUs and majority of patients were frail with underlying peripheral artery disease. (NCT03863054).

Personalized Offloading Treatments for Healing Plantar Diabetic Foot Ulcers

BACKGROUND

Non-removable knee-high devices are the gold-standard offloading treatments to heal plantar diabetic foot ulcers (DFUs). These devices are underused in practice for a variety of reasons. Recommending these devices for all patients, regardless of their circumstances and preferences influencing their ability to tolerate the devices, does not seem a fruitful approach.

PURPOSE

The aim of this article is to explore the potential implications of a more personalized approach to offloading DFUs and suggest avenues for future research and development.

METHODS

Non-removable knee-high devices effectively heal plantar DFUs by reducing plantar pressure and shear at the DFU, reducing weight-bearing activity and enforcing high adherence. We propose that future offloading devices should be developed that aim to optimize these mechanisms according to each individual's needs. We suggest three different approaches may be developed to achieve such personalized offloading treatment. First, we suggest modular devices, where different mechanical features (rocker-bottom sole, knee-high cast walls/struts, etc.) can be added or removed from the device to accommodate different patients' needs and the evolving needs of the patient throughout the treatment period. Second, advanced manufacturing techniques and novel materials could be used to personalize the design of their devices, thereby improving common hindrances to their use, such as devices being heavy, bulky, and hot. Third, sensors could be used to provide real-time feedback to patients and clinicians on plantar pressures, shear, weight-bearing activity, and adherence.

CONCLUSIONS

By the use of these approaches, we could provide patients with personalized devices to optimize plantar tissue stress, thereby improving clinical outcomes.

Cerium-Containing N-Acetyl-6-Aminohexanoic Acid Formulation Accelerates Wound Reparation in Diabetic Animals

Background: The main goal of our study was to explore the wound-healing property of a novel cerium-containing N-acethyl-6-aminohexanoate acid compound and determine key molecular targets of the compound mode of action in diabetic animals. Methods: Cerium N-acetyl-6-aminohexanoate (laboratory name LHT-8-17) as a 10 mg/mL aquatic spray was used as wound experimental topical therapy. LHT-8-17 toxicity was assessed in human skin epidermal cell culture using (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A linear wound was reproduced in 18 outbred white rats with streptozotocin-induced (60 mg/kg i.p.) diabetes; planar cutaneous defect was modelled in 60 C57Bl₆ mice with streptozotocin-induced (200 mg/kg i.p.) diabetes and 90 diabetic db/db mice. Firmness of the forming scar was assessed mechanically. Skin defect covering was histologically evaluated on days 5, 10, 15, and 20. Tissue TNF-α, IL-1β and IL-10 levels were determined by quantitative ELISA. Oxidative stress activity was detected by Fe-induced chemiluminescence. Ki-67 expression and CD34 cell positivity were assessed using immunohistochemistry. FGFR3 gene expression was detected by real-time PCR. LHT-8-17 anti-microbial potency was assessed in wound tissues contaminated by MRSA. Results: LHT-8-17 4 mg twice daily accelerated linear and planar wound healing in animals with type 1 and type 2 diabetes. The formulated topical application depressed tissue TNF-α, IL-1β, and oxidative reaction activity along with sustaining both the IL-10 concentration and antioxidant capacity. LHT-8-17 induced Ki-67 positivity of fibroblasts and pro-keratinocytes, upregulated FGFR3 gene expression, and increased tissue vascularization. The formulation possessed anti-microbial properties. Conclusions: The obtained results allow us to consider the formulation as a promising pharmacological agent for diabetic wound topical treatment.

Silver Sulfadiazine Eradicates Antibiotic-Tolerant Staphylococcus aureus and Pseudomonas aeruginosa Biofilms in Patients with Infected Diabetic Foot Ulcers

Infections are among the most frequent and challenging events in diabetic foot ulcers (DFUs). Pathogenic bacteria growing in biofilms within host tissue are highly tolerant to environmental and chemical agents, including antibiotics. The present study was aimed at assessing the use of silver sulfadiazine (SSD) for wound healing and infection control in 16 patients with DFUs harboring biofilm-growing Staphylococcus aureus and Pseudomonas aeruginosa. All patients received a treatment based on a dressing protocol including disinfection, cleansing, application of SSD, and application of nonadherent gauze, followed by sterile gauze and tibio-breech bandage, in preparation for toilet surgery after 30 days of treatment. Clinical parameters were analyzed by the T.I.M.E. classification system. In addition, the activity of SSD against biofilm-growing S. aureus and P. aeruginosa isolates was assessed in vitro. A total of 16 patients with S. aureus and P. aeruginosa infected DFUs were included in the study. Clinical data showed a statistically significant (p < 0.002) improvement of patients’ DFUs after 30 days of treatment with SSD with significant amelioration of all the parameters analyzed. Notably, after 30 days of treatment, resolution of infection was observed in all DFUs. In vitro analysis showed that both S. aureus and P. aeruginosa isolates developed complex and highly structured biofilms. Antibiotic susceptibility profiles indicated that biofilm cultures were significantly (p ≤ 0.002) more tolerant to all tested antimicrobials than their planktonic counterparts. However, SSD was found to be effective against fully developed biofilms of both S. aureus and P. aeruginosa at concentrations below those normally used in clinical preparations (10 mg/mL). These results strongly suggest that the topical administration of SSD may represent an effective alternative to conventional antibiotics for the successful treatment of DFUs infected by biofilm-growing S. aureus and P. aeruginosa.

Hydrocolloid dressing improves wound healing by increasing M2 macrophage polarization in mice with diabetes

Impaired wound healing is one of the most common complications of diabetes, and is known to be caused by multiple complicated factors. For instance, impaired angiogenesis, neuropathy, and hyperglycemia all function to delay subsequent wound closure. Alternatively, moist wound healing, which provides an appropriate environment for wounds, was reported to permit rapid healing by managing wound exudate. Accordingly, wound dressing materials that facilitate moist healing have been developed. The present study sought to clarify the effects of wound dressing material for moist healing of diabetic wounds, in terms of the dynamics of angiogenic factors and macrophages, using a mouse model of naturally occurring diabetes. Wounds with full-thickness skin defects were inflicted on the backs of mice and covered with dressing materials of hydrogel or gauze (control), which were retained for 3, 5, 7, 10, or 14 days following wound generation. During this time, the localization of neutrophils, fibroblasts and macrophages as well as the expression of vascular endothelial growth factor (VEGF) in the wounds and surrounding areas was observed each day. Healing clearly occurred in the hydrogel group with an increase in neutrophils and the angiogenic factor, VEGF. Moreover, the use of hydrogel resulted in a rapid rise in M1 macrophages, which appeared in the early stage of the injury, as well as rapid subsequent appearance of M2 macrophages. Thus, herein, we demonstrate that the formation of a moist environment via wound dressing material effectively improves diabetic wound healing.

The amputation and survival of patients with diabetic foot based on establishment of prediction model

OBJECTIVE

The objective of this paper is to study the establishment of predictive models and the amputation and survival of patients with diabetic foot.

METHODS

A total of 200 inpatients with diabetic foot were selected as the research subject in this study. The amputation and survival status of diabetic foot patients were followed up by telephone. The relevant indicators were screened by cluster analysis. The predictive model was established respectively based on proportional hazard regression analysis, back propagation neural network (BPNN) and BPNN based on genetic algorithm optimization, and the reliability of the three prediction models (PM) was evaluated and compared.

RESULTS

The risk factors for amputation were severe ulcer disease, glycosylated hemoglobin and low-density lipoprotein cholesterol. The risk factors for death were cerebrovascular disease, severe ulcer disease and peripheral arterial disease. In case that the outcome was amputation, the PM of BPNN and the PM of BPNN based on genetic algorithm optimization have obviously higher AUC (area under the receiver operating characteristic curve) than the PM of proportional hazard regression analysis, and the difference was statistically significant (P < 0.05). Among the three PMs, the PM based on BPNN had the highest AUC, sensitivity and specificity (SAS). In case that the outcome was death, the PM of BPNN and the PM of BPNN based on genetic algorithm optimization had almost the same AUC, and were obviously higher than the PM based on proportional hazard regression analysis. The difference was statistically significant (P < 0.05). The PM based on BPNN and the BPNN based on genetic algorithm optimization had higher SAS than the PM based on COX regression analysis.

CONCLUSION

The PM of BPNN and BPNN based on genetic algorithm optimization have better prediction effect than the PM based on proportional hazard regression analysis. It can be used for amputation and survival analysis of diabetic foot patients.

Mitochondrial dysfunction is the cause of one of the earliest changes seen on magnetic resonance imaging in Charcot neuroarthopathy - Oedema of the small muscles in the foot

The hypothesis laid out in this thesis states that the early changes seen on an MR imaging in those with early Charcot neuroarthopathy may be due to mitochondrial dysfunction. In a Charcot foot, there is movement between bones. In an attempt to prevent this movement, the small muscles of the foot contract continuously when the foot is weight bearing. This contraction takes energy in the form of ATP. However, the reduction of glucose transport into the muscle cells due to insulin resistance / insufficiency, leads to reduction in the ATP producing capacity of the mitochondria. The ATP depletion affects the cell membrane gradient leading to mitochondrial and cellular swelling. These early cellular changes could then be picked up with MR imaging as muscle oedema.

Cutaneous Wound Healing in Diabetic Mice Is Improved by Topical Mineralocorticoid Receptor Blockade

Skin ulcers resulting from impaired wound healing are a serious complication of diabetes. Unresolved inflammation, associated with the dysregulation of both the phenotype and function of macrophages, is involved in the poor healing of diabetic wounds. Here, we report that topical pharmacological inhibition of the mineralocorticoid receptor (MR) by canrenoate or MR small interfering RNA can resolve inflammation to improve delayed skin wound healing in diabetic mouse models; importantly, wounds from normal mice are unaffected. The beneficial effect of canrenoate is associated with an increased ratio of anti-inflammatory M2 macrophages to proinflammatory M1 macrophages in diabetic wounds. Furthermore, we show that MR blockade leads to downregulation of the MR target, LCN2, which may facilitate macrophage polarization toward the M2 phenotype and improve impaired angiogenesis in diabetic wounds. Indeed, diabetic LCN2-deficient mice showed improved wound healing associated with macrophage M2 polarization and angiogenesis. In addition, recombinant LCN2 protein prevented IL-4-induced macrophage switch from M1 to M2 phenotype. In conclusion, topical MR blockade accelerates skin wound healing in diabetic mice via LCN2 reduction, M2 macrophage polarization, prevention of inflammation, and induction of angiogenesis.

Appraisal of Biofilm Formation in Diabetic Foot Infections by Comparing Phenotypic Methods With the Ultrastructural Analysis

Diabetic patients are more prone to the development of foot ulcers, because their underlying tissues are exposed to colonization by various pathogenic organisms. Hence, biofilm formation plays a vital role in disease progression by antibiotic resistance to the pathogen found in foot infections. The present study has demonstrated the correlation of biofilm assay with the clinical characteristics of diabetic foot infection. The clinical characteristics such as the ulcer duration, size, nature, and grade were associated with biofilm production. Our results suggest that as the size of the ulcer with poor glycemic control increased, the organism was more likely to be positive for biofilm formation. A high-degree of antibiotic resistance was exhibited by the biofilm-producing gram-positive isolates for erythromycin and gram-negative isolates for cefpodoxime. Comparisons of biofilm production using 3 different conventional methods were performed. The strong producers with the tube adherence method were able to produce biofilm using the cover slip assay method, and the weak producers in tube adherence method had difficulty in producing biofilm using the other 2 methods, indicating that the tube adherence method is the best method for assessing biofilm formation. The strong production of biofilm with the conventional method was further confirmed by scanning electron microscopy analysis, because bacteria attached as a distinct layer of biofilm. Thus, the high degree of antibiotic resistance was exhibited by biofilm producers compared with nonbiofilm producers. The tube adherence and cover slip assay were found to be the better method for biofilm evaluation.

New trends in the orthopaedic management of diabetic foot

Although there are various types of therapeutic footwear currently used to treat diabetic foot ulcers (DFUs), recent literature has enforced the concept that total-contact casts are the benchmark.Besides conventional clinical tests and imaging modalities, advanced MRI techniques and high-sensitivity nuclear medicine modalities present several advantages for the investigation of diabetic foot problems.The currently accepted principles of DFU care are rigorous debridement followed by modern wound dressings to provide a moist wound environment. Recently, hyperbaric oxygen and negative pressure wound therapy have aroused increasing attention as an adjunctive treatment for patients with DFUs.For DFU, various surgical treatments are currently available, including resection arthroplasty, metatarsal osteotomies and metatarsal head resections.In the modern management of the Charcot foot, surgery in the acute phase remains controversial and under investigation. While conventional fixation techniques are frequently insufficient to keep alignment postoperatively, superconstruct techniques could provide a successful fixation.Retrograde intramedullary nailing has been a generally accepted method of achieving stability. The midfoot fusion bolt is a current treatment device that maintains the longitudinal columns of the foot. Also, Achilles tendon lengthening remains a popular method in the management of Charcot foot. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170073.

Linking challenges in wound healing: key highlights from the Hartmann congress

With a special focus on advanced wound healing (wound bed preparation, epithelialisation and hydration) and negative pressure wound therapy, the Hartmann LINK for Wound Healing Congress took place in Belfast, Northern Ireland, on 19 September. The event aimed to promote the latest advances in wound care and highlight the main challenges that clinicians face when treating different types of wounds. Annabel De Coster, editor of the British Journal of Community Nursing, gives an overview of selected talks from the congress.

IL-33 improves wound healing through enhanced M2 macrophage polarization in diabetic mice

IL-33 is a newly discovered member of the IL-1 family and has been identified as a potent inducer of Th2 type immunity. Emerging evidence imply that IL-33 may also act as an alarm to alert the immune system when released by epithelial barrier tissues during trauma or infection. In this study, we further investigate the potential efficacy of IL-33 on dermal wound healing in streptozotocin-induced diabetic mice. A full-thickness skin wound was generated on the back of diabetic mice and treated with IL-33 or vehicle topically. Our data showed that IL-33 delivery contributed to diabetic wound closure with wounds gaping narrower and exhibiting elevated re-epithelialization. IL-33 promoted the new extracellular matrix (ECM) deposition and angiogenesis formation, which indicates an important role of IL-33 on matrix synthesis and neovascularization. Meanwhile, IL-33 accelerated the development of M2 macrophages in wound sites in vivo, and amplified IL-13-induced polarization of bone marrow-derived macrophages toward a M2 phenotype in vitro. Furthermore, IL-33-amplified M2 macrophages augmented the proliferation of fibroblasts and ECM deposition. All together, these results strongly suggest manipulation of IL-33-mediated signal might be a potential therapeutic approach for diabetic skin wounds.