What's new in the literature: an update of new research since the original WHS diabetic foot ulcer guidelines in 2006

Management of diabetic foot ulcers: a narrative review

Diabetic foot ulcers (DFUs) are among the most serious complications of diabetes and are a source of reduced quality of life and financial burden for the people involved. For effective DFU management, an evidence-based treatment strategy that considers the patient's clinical context and wound condition is required. This treatment strategy should include conventional practices (surgical debridement, antibiotics, vascular assessment, offloading, and amputation) coordinated by interdisciplinary DFU experts. In addition, several adjuvant therapies can be considered for nonhealing wounds. In this narrative review, we aim to highlight the current trends in DFU management and review the up-to-date guidelines.

Lower-limb peripheral arterial disease and amputations in people with diabetes: Risk factors, prognostic value and management

Lower-limb peripheral arterial disease (PAD), is a common manifestation of systemic atherosclerosis, resulting from a partial or complete obstruction of at least one lower-limb arteries. PAD is a major endemic disease with an excess risk of major cardiovascular events and death. It also leads to disability, high rates of lower-limb adverse events and non-traumatic amputation. In patients with diabetes, PAD is particularly frequent and has a worse prognosis than in patients without diabetes. The risk factors of PAD are comparable to those for cardiovascular disease. The ankle-brachial index is usually recommended to screen PAD despite its limited performance in patients with diabetes, affected by the presence of peripheral neuropathy, medial arterial calcification, incompressible arteries and infection. Toe brachial index and toe pressure emerge as alternative screening tools. The management of PAD requires strict control of cardiovascular risk factors including diabetes, hypertension and dyslipidaemia, the use of antiplatelet agents and lifestyle management, to reduce cardiovascular adverse events, but few randomized controlled trials have evaluated the benefits of these treatments in PAD. Several advances have been achieved in endovascular and surgical revascularization procedures, with obvious improvement in PAD prognosis. Further studies are required to increase our understanding of the pathophysiology of PAD and to evaluate the interest of different therapeutic strategies in the occurrence and progression of PAD in patients with diabetes. Here, we present a narrative and contemporary review to synthesize the key epidemiology findings, screening and diagnosis methods, and major therapeutic advances regarding PAD in patients with diabetes.

Mapping intellectual structure and research hotspots in the field of fibroblast-associated DFUs: a bibliometric analysis

Background

Diabetic foot ulcers (DFUs) are one of the most popular and severe complications of diabetes. The persistent non-healing of DFUs may eventually contribute to severe complications such as amputation, which presents patients with significant physical and psychological challenges. Fibroblasts are critical cells in wound healing and perform essential roles in all phases of wound healing. In diabetic foot patients, the disruption of fibroblast function exacerbates the non-healing of the wound. This study aimed to summarize the hotspots and evaluate the global research trends on fibroblast-related DFUs through bibliometric analysis.

Methods

Scientific publications on the study of fibroblast-related DFUs from January 1, 2000 to April 27, 2022 were retrieved from the Web of Science Core Collection (WoSCC). Biblioshiny software was primarily performed for the visual analysis of the literature, CiteSpace software and VOSviewer software were used to validate the results.

Results

A total of 479 articles on fibroblast-related DFUs were retrieved. The most published countries, institutions, journals, and authors in this field were the USA, The Chinese University of Hong Kong, Wound Repair and Regeneration, and Seung-Kyu Han. In addition, keyword co-occurrence networks, historical direct citation networks, thematic map, and the trend topics map summarize the research hotspots and trends in this field.

Conclusion

Current studies indicated that research on fibroblast-related DFUs is attracting increasing concern and have clinical implications. The cellular and molecular mechanisms of the DFU pathophysiological process, the molecular mechanisms and therapeutic targets associated with DFUs angiogenesis, and the measures to promote DFUs wound healing are three worthy research hotspots in this field.

Mesenchymal stem cell-derived exosomes: The dawn of diabetic wound healing

Chronic wound healing has long been an unmet medical need in the field of wound repair, with diabetes being one of the major etiologies. Diabetic chronic wounds (DCWs), especially diabetic foot ulcers, are one of the most threatening chronic complications of diabetes. Although the treatment strategies, drugs, and dressings for DCWs have made great progress, they remain ineffective in some patients with refractory wounds. Stem cell-based therapies have achieved specific efficacy in various fields, with mesenchymal stem cells (MSCs) being the most widely used. Although MSCs have achieved good feedback in preclinical studies and clinical trials in the treatment of cutaneous wounds or other situations, the potential safety concerns associated with allogeneic/autologous stem cells and unknown long-term health effects need further attention and supervision. Recent studies have reported that stem cells mainly exert their trauma repair effects through paracrine secretion, and exosomes play an important role in intercellular communication as their main bioactive component. MSC-derived exosomes (MSC-Exos) inherit the powerful inflammation and immune modulation, angiogenesis, cell proliferation and migration promotion, oxidative stress alleviation, collagen remodeling imbalances regulation of their parental cells, and can avoid the potential risks of direct stem cell transplantation to a large extent, thus demonstrating promising performance as novel "cell-free" therapies in chronic wounds. This review aimed to elucidate the potential mechanism and update the progress of MSC-Exos in DCW healing, thereby providing new therapeutic directions for DCWs that are difficult to be cured using conventional therapy.

A new precise way to guide the debridement process of diabetic foot ulcer using indocyanine green fluorescence molecular imaging

OBJECTIVE

The purpose of this study was to estimate the value of a novel imaging technique in necrotic tissue debridement of diabetic foot ulcers (DFU), using near-infrared (NIR) fluorescence molecular imaging (FMI) of indocyanine green (ICG).

METHODS

The patients with DFU were included and divided into a FMI navigation debridement group and a traditional group. The FMI of the wounds and the debridement effect of each group was analyzed, including debridement frequency, length of hospital stay, and the histological examination of removed tissue.

RESULT

A total of 40 patients with DFU (23 cases in the FMI group and 17 cases in the traditional group) were included in this study. The positive rate of wound fluorescence in the FMI group was 96%, and no patients had related side effects. The pathological examination confirmed that the tissue emitting NIR fluorescence was totally necrotic tissue. In addition, the debridement frequency in the FMI group is less than that in the traditional group, but there is no difference in the length of hospital stay between the two groups.

CONCLUSION

ICG FMI technique can accurately illuminated necrotic tissue, with high sensitivity, easy operation and good safety, which would be a new way to precisly guide the process of debridement in the clinic.

Extracellular Vesicles from HIF-1α-Overexpressing Adipose-Derived Stem Cells Restore Diabetic Wounds Through Accelerated Fibroblast Proliferation and Migration

PURPOSE

Inhibition of cellular adaptation to hypoxia can cause persistent inflammation, thereby increasing tissue damage and complicating wound healing in diabetes patients. Regulating cellular adaptation to hypoxic environments can help in effective wound repair. Hypoxia-inducible factor (HIF)-1α is a key regulator of cell hypoxia. Extracellular vesicles (EVs) regulate wound repair. This study investigated the mechanism of HIF-1α overexpression in adipose-derived stem cell extracellular vesicles (ADSCs-hEVs) in the repair of diabetic wounds.

MATERIALS AND METHODS

HIF-1α expression in diabetes patients and healthy participants was studied. High-throughput sequencing, GO, and KEGG analysis revealed that ADSCs small extracellular vesicle hypoxia environments may increase HIF-1α expression by affecting cell metabolism, differentiation, and TGF-β secretion, or by altering the PI3K/AKT pathway. Effect of addition of ADSCs-hEVs on cell proliferation and migration was investigated using Western blotting, EdU assay, transwell assay, and migration. In vivo, after 7, 14, and 21 days, important factors for diabetic wound healing were evaluated by immunohistochemistry, qRT-PCR, Masson staining, and H&E staining.

RESULTS

HIF-1α expression decreased in the skin of diabetes patients; interleukin (IL)-6 expression increased, and growth factor-related indexes decreased. ADSCs-hEVs significantly increased the expression and secretion of growth factors, compared with ADSCs-EVs. In vivo, ADSC-hEV treatment accelerated the healing rate and improved the healing quality of diabetic wounds compared with ADSCs-EVs.

CONCLUSION

Speed and quality of wound healing increased significantly in the ADSCs-hEVs group, which could inhibit early inflammation while promoting the secretion and expression of growth factors and extracellular matrix-related indexes.

Hypoxia adipose stem cell-derived exosomes promote high-quality healing of diabetic wound involves activation of PI3K/Akt pathways

Refractory diabetic wounds can cause persistent inflammation and delayed healing due to hypoxia. Currently, no optimal solution is available. Exosomes of adipose stem cells (ADSCs-exo) may promote skin wound healing, however, molecular mechanisms remains mysterious. We found significantly enhanced survival and proliferation of adipose stem cells after hypoxia induction compared to normoxia. Here, we aimed to investigate if hypoxic adipose stem cells exosomes (HypADSCs-exo) participate in hypoxia adaptability and accelerate diabetic wound healing. Based on high-throughput sequencing, 215 microRNAs (miRNAs) were upregulated and 369 miRNAs downregulated in HypADSCs-exo compared to ADSCs-exo. Up-regulated miR-21-3p, miR-126-5p, miR-31-5p whereas down-regulated gene miR-99b and miR-146-a correlated with wound healing. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), miRNAs might regulate cell metabolism, differentiation and Transforming growth factor-β (TGF-β) function. Consistently, HpyADSCs-exo could promote diabetic wounds healing and inhibit inflammation through PI3K/AKT signaling pathway. Collectively, HpyADSCs-exo can promote diabetic wound healing as an alternative strategy to improve wound healing.

Managing Diabetic Foot Ulcers: Pharmacotherapy for Wound Healing

Historically, there has been a scarcity of evidence-based topical therapy to hasten the healing of diabetic foot ulcers. But recently new evidence-based treatments have emerged from multicentre, randomised, controlled trials. This article highlights those trials, and describes the current pharmacological management of the diabetic foot ulcer and the advances that have been made in wound therapy to date. It provides an overview of topical and systemic pharmacotherapies in current use and those in development for future use in managing the diabetic foot. For each treatment, proposed mechanisms of action and evidence available to support their clinical use are presented. There is supporting randomised, controlled evidence for sucrose octasulfate in the treatment of neuro-ischaemic ulcers, and multi-layered patch of autologous leucocytes, platelets and fibrin in ulcers with or without ischaemia. There is also evidence for placentally derived products and for topical and systemic oxygen therapy in the healing of diabetic foot ulcers. Growth factors, bio-engineered tissues, stem cell therapy, gene therapy and peptide therapy also have some supporting evidence in the healing of diabetic foot ulcers. Nonsurgical debriding agents may be useful when the optimum approach of sharp debridement is not possible, and immunomodulators may be helpful for their antimicrobial effects, but robust data is still required to strengthen the case for general use. The review does not cover antimicrobials as their primary role are as anti-infectives and not in wound healing. The development of nanotechnology has created a means of prolonging the bioavailability of target molecules at the wound site, with the use of glass/hydrogel nanoparticles, polyethylene glycol and hyaluronic acid. Looking forward, novel therapies, including traction force-activated payloads, local delivery of short-interfering RNA and finally hydrogels incorporating bioactive agents or cells may provide possibilities for pharmacotherapy in the future.

A Severe Diabetic Foot Ulcer With Intermediate Cuneiform Displacement and Multidrug-Resistant Pseudomonas aeruginosa Infection: A Rare Case Report

Diabetic foot ulcer (DFU) is considered as one of the most serious and prevailing complications of diabetes mellitus, while it is the major cause of amputations in diabetic patients. Herein, we reported an acquired severe traumatic DFU with an intermediate cuneiform hairline fracture and displacement in a 55-year old male (Grade IV of Wagner classification; Grade III of IWGDF classification). The Pseudomonas aeruginosa was identified in pus culture. Data of antibiotic susceptibility testing indicated that the isolates of Pseudomonas aeruginosa were multi-drug resistant. Routine debridement, clearing displaced intermediate cuneiform and drainage were performed to facilitate the outflow of pus and pressure mitigation. Dressing with Prontosan solution and gel was applied to the wound, and meropenem was systemically administrated in addition to effective glycemic control. The DFU has been fully healed after ~40-day treatment. For this case, clearing the displaced and fractured intermediate cuneiform is essential for the heal of the DFU in addition to the common strategy for DFU treatment, i.e., the combination of debridement, pressure mitigation, wound dressing with Prontosan, antibiotic selection and effective glycemic control. This case report might have value for the treatment of complex DFU with bone fracture and displacement, reducing the risk of amputation.

Erbium: Yttrium Aluminum Garnet Laser Accelerates Healing in Indolent Diabetic Foot Ulcers

The objective of the study was to evaluate the effect of the erbium:yttrium aluminum garnet (YAG) laser on diabetic foot ulcers (DFUs) that had not responded to standard care. We retrospectively evaluated 22 nonhealing DFUs that received at least 4 weeks of standard wound care, demonstrated poor healing response, and subsequently were treated with an erbium:YAG laser. We measured the percent wound area reduction (PWAR) for the 4 weeks before initiating laser therapy and the PWAR for 4 weeks after the initiation of laser therapy. Erbium:YAG laser treatment consisted of 2 components: debridement and resurfacing. The laser settings were the same for all treatments. We used the paired t test to compare pretreatment with posttreatment wound area reduction. During the 4-week period before the initiation of laser therapy, the average PWAR was -33.6%. Four weeks after initiating treatment with the erbium:YAG laser, the average PWAR was 63.4% (p = .002) and 72.7% of wounds had ≥50% PWAR. By 12 weeks, 50% of wounds had healed. Erbium:YAG laser therapy accelerated DFU healing in a cohort of patients with ulcers that had been unresponsive to standard of care therapy.

Redox Profiling Reveals Clear Differences between Molecular Patterns of Wound Fluids from Acute and Chronic Wounds

Wound healing is a complex multiphase process which can be hampered by many factors including impaired local circulation, hypoxia, infection, malnutrition, immunosuppression, and metabolic dysregulation in diabetes. Redox dysregulation is a common feature of many skin diseases demonstrated by virtually all cell types in the skin with overproduction of reactive oxygen and nitrogen species. The objective of this study was to characterize the redox environment in wound fluids and sera from patients suffering from chronic leg ulcers (n = 19) and acute wounds (bulla fluids from second degree burns; n = 11) with serum data also compared to those from healthy volunteers (n = 7). Significantly higher concentrations of TNF-α, interleukine-8, vascular endothelial growth factor, and lactate dehydrogenase (measure of cell damage) were found in fluids from chronic wounds compared to acute ones. The extent of protein carbonylation (measure of protein oxidation), lipid peroxidation, and tyrosine nitration (indicator of peroxynitrite production) was similar in acute and chronic wound fluids, while radical scavenging activity and glutathione (GSH) levels were elevated in chronic wound fluids compared to acute wounds. Sera were also assessed for the same set of parameters with no significant differences detected. Nitrotyrosine (the footprint of the potent oxidant peroxynitrite) and poly(ADP-ribose) (the product of the DNA damage sensor enzyme PARP-1) could be detected in wound biopsies. Our data identify multiple signs of redox stress in chronic wounds with notable differences. In chronic wounds, elevations in antioxidant levels/activities may indicate compensatory mechanisms against inflammation. The presence of nitrotyrosine and poly(ADP-ribose) in tissues from venous leg ulcers indicate peroxynitrite production and PARP activation in chronic wounds.

Update on management of diabetic foot ulcers

Diabetic foot ulcers (DFUs) are a serious complication of diabetes that results in significant morbidity and mortality. Mortality rates associated with the development of a DFU are estimated to be 5% in the first 12 months, and 5-year morality rates have been estimated at 42%. The standard practices in DFU management include surgical debridement, dressings to facilitate a moist wound environment and exudate control, wound off-loading, vascular assessment, and infection and glycemic control. These practices are best coordinated by a multidisciplinary diabetic foot wound clinic. Even with this comprehensive approach, there is still room for improvement in DFU outcomes. Several adjuvant therapies have been studied to reduce DFU healing times and amputation rates. We reviewed the rationale and guidelines for current standard of care practices and reviewed the evidence for the efficacy of adjuvant agents. The adjuvant therapies reviewed include the following categories: nonsurgical debridement agents, dressings and topical agents, oxygen therapies, negative pressure wound therapy, acellular bioproducts, human growth factors, energy-based therapies, and systemic therapies. Many of these agents have been found to be beneficial in improving wound healing rates, although a large proportion of the data are small, randomized controlled trials with high risks of bias.

A Retrospective Case Series of a Dehydrated Amniotic Membrane Allograft for Treatment of Unresolved Diabetic Foot Ulcers

BACKGROUND

Foot ulcers are among the most serious complications of diabetes and can lead to amputation. Diabetic foot ulcers (DFUs) often fail to heal with standard wound care, thereby making new treatments necessary. This case series describes the addition of a dehydrated amniotic membrane allograft (DAMA) to standard care in unresolved DFUs.

METHODS

This is a single-center retrospective chart review of eight patients who had one to three applications of DAMA to nine DFUs that had failed to resolve despite offloading, other standard care, and adjuvant therapies. Following initial DAMA placement, wound size (length, width, depth) was measured every 1 to 2 weeks until closure. The principal outcome assessed was mean time to wound closure; other outcomes included mean percent reduction from baseline in wound area and volume at weeks 2 to 8.

RESULTS

All wounds were closed a mean of 9.2 weeks after the first DAMA application (range, 3.0-13.5 weeks). Compared with baseline, wound area and volume, respectively, were reduced by a mean of 48% and 60% at week 2 and by 89% and 91% at week 8. Time to closure was shorter among four patients who had three DAMA applications (mean, 8.3 weeks; range, 4.0-11.0 weeks) than among three patients who had only one application (mean, 12.1 weeks; range, 9.5-13.5 weeks).

CONCLUSIONS

Chronic, unresolved DFUs treated with DAMA rapidly improved and reached closure in an average of 9.2 weeks. These cases suggest that DAMA can facilitate closure of DFUs that have failed to respond to standard treatments.

Surgical treatment strategy for diabetic forefoot osteomyelitis

The aim of this study was to propose an appropriate surgical treatment for diabetic forefoot osteomyelitis (DFO) involving ischemia or moderate to severe soft tissue infection. The records of 28 patients with osteomyelitis from 2009 to 2015 were retrospectively studied. All patients had undergone surgery based on preoperative magnetic resonance imaging examinations and histopathological or culture analyses confirming the surgical bone margin. The appropriate surgical margin, crucial factors for early healing, and prognosis after complete resection of osteomyelitis were examined. After healing, patients were followed up to assess prognosis (range 32-1,910 days, median 546 days). The healing rate of nonischemic cases of DFO with negative surgical margins was 100% and that of ischemic cases was 84.6%; the ambulatory rates for both types of cases were 100%. No wound (and/or osteomyelitis) recurrence was observed. Nine new cases of DFO developed in six patients (21.4%; eight were due to vascular stenosis, and one was due to biomechanical changes in the foot. After complete resection of osteomyelitis, preoperative and postoperative C-reactive protein levels and the size of the ulcer were significant predictors of early healing (p < 0.05, 0.01, and 0.05, respectively). The appropriate surgical margin should be set in the area of bone marrow edema, based on magnetic resonance imaging examinations after revascularization. In cases with high preoperative or postoperative C-reactive protein levels, long-term antibiotic therapy is recommended, and surgery should be planned after the C-reactive protein levels decrease, except in emergencies.