The role of surgical revascularization in the management of diabetic foot wounds

Investigation and management of diabetic foot osteomyelitis: An update for the foot and ankle orthopaedic surgeon

Diabetic foot osteomyelitis (DFO) poses a significant challenge in the management of diabetic patients, often leading to severe complications and increased morbidity. Effective management of DFO requires a multidisciplinary approach, involving endocrinologists, infectious disease specialists, vascular surgeons, orthopaedic surgeons, and wound care experts. Early diagnosis is paramount, facilitated by advanced imaging techniques such as magnetic resonance imaging (MRI) and bone scintigraphy. Once diagnosed, the treatment strategy hinges on a combination of medical and surgical interventions. Antibiotic therapy, guided by culture results, plays a central role in managing DFO. Tailored regimens targeting the specific pathogens involved are administered, often for prolonged durations. Surgical intervention becomes necessary when conservative measures fall short. Surgical approaches range from minimally invasive procedures, like percutaneous drainage, to more extensive interventions like debridement and bone resection. Prevention of DFO recurrence is equally vital, emphasising glycemic control, meticulous foot care, patient education, monitoring of at-risk signs, revascularization and early intervention when indicated. The management of diabetic foot osteomyelitis mandates a comprehensive strategy that addresses both the infectious and surgical aspects of the condition. A collaborative, interdisciplinary approach ensures timely diagnosis, tailored treatment, and holistic care. Further research into novel therapeutic modalities and long-term outcomes remains essential in refining the management of this complex and debilitating complication of diabetes.

A focused review on hyaluronic acid contained nanofiber formulations for diabetic wound healing

The significant clinical challenge presented by diabetic wounds is due to their impaired healing process and increased risk of complications. It is estimated that a foot ulcer will develop at some point in the lives of 15-25 % of diabetic patients. Serious complications, including infection and amputation, are often led to by these wounds. In the field of tissue engineering and regenerative medicine, nanofiber-based wound dressings have emerged in recent years as promising therapeutic strategies for diabetic wound healing. Hyaluronic acid (HA), among various nanofiber materials, has gained considerable attention due to its unique properties, including biocompatibility, biodegradability, and excellent moisture retention capacity. By promoting skin hydration and controlling inflammation, a crucial role in wound healing is played by HA. Wounds are also helped to heal faster by HA through the regulation of inflammation levels and signaling the body to build more blood vessels in the damaged area. Great potential in various applications, including wound healing, has been shown by the development and use of nanofiber formulations in medicine. However, challenges and limitations associated with nanofibers in medicine exist, such as reproducibility, proper characterization, and biological evaluation. By providing a biomimetic environment that enhances re-epithelialization and facilitates the delivery of active substances, nanofibers promote wound healing. In accelerating wound healing, promising results have been shown by HA-contained nanofiber formulations in diabetic wounds. Key strategies employed by these formulations include revascularization, modulation of the inflammation microenvironment, delivery of active substances, photothermal nanofibers, and nanoparticle-loaded fabrics. Particularly crucial is revascularization as it restores blood flow to the wound area, promoting healing. Wound healing can also be enhanced by modulating the inflammation microenvironment through controlling inflammation levels. Future perspectives in this field involve addressing the current challenges and limitations of nanofiber technology and further optimizing HA-contained nanofiber formulations for improved efficacy in diabetic wound healing. This includes exploring new fabrication techniques, enhancing the biocompatibility and biodegradability of nanofibers, and developing multifunctional nanofibers for targeted drug delivery. Not only does writing a review in the field of nanofiber-based wound dressings, particularly those containing hyaluronic acid, allow us to consolidate our current knowledge and understanding but also broadens our horizons. An opportunity is provided to delve deeper into the intricacies of this innovative therapeutic strategy, explore its potential and limitations, and envision future directions. By doing so, a contribution can be made to the ongoing advancements in tissue engineering and regenerative medicine, ultimately improving the quality of life for patients with diabetic wounds.

LncRNA MALAT1 Regulates Hyperglycemia Induced EMT in Keratinocyte via miR-205

Epithelial-to-mesenchymal transition (EMT) is critical to cutaneous wound healing. When skin is injured, EMT activates and mobilizes keratinocytes toward the wound bed, therefore enabling re-epithelialization. This process becomes dysregulated in patients with diabetes mellitus (DM). Long non-coding RNAs (lncRNAs) regulate many biological processes. LncRNA-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) influences numerous cellular processes, including EMT. The objective of the current study is to explore the role of MALAT1 in hyperglycemia (HG)-induced EMT. The expression of MALAT1 was found to be significantly upregulated, while the expression of miR-205 was downregulated in diabetic wounds and high-glucose-treated HaCaT cells. The initiation of EMT in HaCaT cells from hyperglycemia was confirmed by a morphological change, the increased expression of CDH2, KRT10, and ACTA2, and the downregulation of CDH1. The knockdown of MALAT1 was achieved by transfecting a small interfering RNA (SiRNA). MALAT1 and miR-205 were found to modulate HG-induced EMT. MALAT1 silencing or miR-205 overexpression appears to attenuate hyperglycemia-induced EMT. Mechanistically, MALAT1 affects HG-induced EMT through binding to miR-205 and therefore inducing ZEB1, a critical transcription factor for EMT. In summary, lncRNA MALAT1 is involved in the hyperglycemia-induced EMT of human HaCaT cells. This provides a new perspective on the pathogenesis of diabetic wounds.

EGFL7 affects the migration of epidermal stem cells in refractory diabetic wounds by regulating Notch signaling pathway

Aim: This study aimed to explore the role of EGFL7 in the healing process of refractory diabetic wounds. Methods: Epidermal stem cells (ESCs) were isolated from healthy mice and diabetic mice, identified by immunofluorescence, transfected with EGFL7 overexpression and silencing lentiviral vectors, and treated with Notch pathway inhibitor (DAPT). Results: SiEGFL7 significantly inhibited the proliferation, invasion and migration of ESCs of healthy mice. DAPT prominently inhibited the expressions of Notch1, Notch2, Hes1 and Jag1 in ESCs of healthy mice induced by overexpressed EGFL7. Overexpressed EGFL7 promoted wound healing in diabetic mice with refractory wounds. Conclusion: EGFL7 affects the proliferation and migration of ESCs in refractory diabetic wounds by regulating the Notch signaling pathway.

Level of Agreement Between Systematic Doppler Examination of the Lower Extremity and Diagnostic Angiography in the Setting of Peripheral Arterial Disease

BACKGROUND

The objective of this investigation was to determine the level of agreement between a systematic clinical Doppler examination of the foot and ankle and diagnostic peripheral angiography.

METHODS

The described Doppler examination technique attempted to determine the patency, quality, and direction of the flow through the dorsalis pedis artery, posterior tibial artery, terminal branches of the peroneal artery, and vascular arch of the foot. These results were then compared with angiographic distal run-off images as interpreted by a blinded vascular surgeon.

RESULTS

Levels of agreement with respect to artery patency/quality ranged from 64.0% to 84.0%. Sensitivity ranged from 53.8% to 84.2%, and specificity ranged from 64.7% to 91.7%. Agreement with respect to arterial flow direction ranged from 73.3% to 90.5%.

CONCLUSIONS

We interpret these results to indicate that this comprehensive physical examination technique of the arterial flow to the foot and ankle with a Doppler device might serve as a reasonable initial surrogate to diagnostic angiography in some patients with peripheral arterial disease.

Diabetic foot ulcers: Epidemiology and the role of multidisciplinary care teams

Diabetic foot ulcers (DFUs) are a common but highly morbid complication of long-standing diabetes, carrying high rates of associated major amputation and mortality. As the global incidence of diabetes has increased, along with the lifespan of the diabetic patient, the worldwide burden of DFUs has grown steadily. Outcomes in diabetes and DFUs are known to depend strongly on social determinants of health, with worse outcomes noted in minority and socioeconomically disadvantaged populations. Effective treatment of DFUs is complex, requiring considerable expenditure of resources and significant cost to the health care system. Comprehensive care models with multidisciplinary teams have proven effective in the treatment of DFUs by decreasing barriers to care and increasing access to the multiple specialists required to provide timely and effective DFU procedural intervention, surveillance, and preventative care. Vascular surgeons are an integral part throughout the cycle of care for DFUs and should be involved early in the course of such patients to maximize their contributions to a multidisciplinary care model.

Mechanisms of mesenchymal stem cell correction of the impaired biomechanical properties of diabetic skin: The role of miR-29a

Diabetic skin has impaired wound healing properties following injury. We have further shown that diabetic skin has weakened biomechanical properties at baseline. We hypothesize that the biomechanical properties of diabetic skin decline during the progression of the diabetic phenotype, and that this decline is due to the dysregulation of miR-29a, resulting in decreased collagen content. We further hypothesize that treatment with mesenchymal stem cells (MSCs) may improve diabetic wound healing by correction of the dysregulated miR-29a expression. We analyzed the biomechanical properties, collagen gene expression, collagen protein production, and miR-29a levels in skin harvested from 6 to 18 week old mice during the development of the diabetic phenotype. We also examined the correction of these impairments by both MSC treatment and the inhibition of miR-29a. Diabetic skin demonstrated a progressive impairment of biomechanical properties, decreased collagen content, and increased miR-29a levels during the development of the diabetic phenotype. MSC treatment decreased miR-29a levels, increased collagen content, and corrected the impaired biomechanical properties of diabetic skin. Additionally, direct inhibition of miR-29a also increased collagen content in diabetic skin. This decline in the biomechanical properties of diabetic skin during the progression of diabetes may increase the susceptibility of diabetic skin to injury and miR-29a appears to play a key role in this process.

Long-term outcomes of infrainguinal bypass surgery for patients with diabetes mellitus and tissue loss

Purpose

To determine the long-term outcomes of patients with diabetes mellitus (DM) and tissue loss who have undergone infrainguinal bypass surgery (IBS).

Methods

We retrospectively reviewed the medical records of 91 patients with DM and tissue loss who underwent IBS between July 2003 and December 2013. We determined the rates of overall survival (OS), amputation-free survival (AFS), limb salvage (LS), and graft patency (GP). In addition, we evaluated data to identify risk factors that affected long-term outcomes.

Results

The mean age of patients was 66 ± 8 years, and 78 patients (85.7%) were men. The locations of tissue loss were toe on 76 limbs (71.6%), heel on 6 limbs (5.7%) and others on 24 limbs (22.6%). Single lesions were found in 81 limbs (76.4%). According to categorization by distal anastomosis artery, there were 57 popliteal (53.8%) and 49 infrapopliteal bypasses (46.2%). Among infrapopliteal bypasses, 5 cases (10.2%) were sequential bypasses. The OS at 1, 3, and 5 years was 90.5%, 70.9%, and 44.2%, respectively. At 1, 3, and 5 years, the LS was 92.1%, 88.9%, 88.9%, respectively; and AFS was 84.4%, 67.6%, 45.7%, respectively. At 1, 3, and 5 years, the GP was 84.8%, 74.5%, and 69.8%, respectively. Renal failure was a negative predictor for OS, and female gender was a negative predictor for GP.

Conclusion

IBS for patients with DM and tissue loss led to acceptable OS, AFS, LS, and GP. Active revascularization for patients with DM and tissue loss can reduce the risk of major amputation.

Does PGE₁ vasodilator prevent orthopaedic implant-related infection in diabetes? Preliminary results in a mouse model

BACKGROUND

Implant-related infections are characterized by bacterial colonization and biofilm formation on the prosthesis. Diabetes represents one of the risk factors that increase the chances of prosthetic infections because of related severe peripheral vascular disease. Vasodilatation can be a therapeutic option to overcome diabetic vascular damages and increase the local blood supply. In this study, the effect of a PGE₁ vasodilator on the incidence of surgical infections in diabetic mice was investigated.

METHODOLOGY

A S. aureus implant-related infection was induced in femurs of diabetic mice, then differently treated with a third generation cephalosporin alone or associated with a PGE₁ vasodilator. Variations in mouse body weight were evaluated as index of animal welfare. The femurs were harvested after 28 days and underwent both qualitative and quantitative analysis as micro-CT, histological and microbiological analyses.

RESULTS

The analysis performed in this study demonstrated the increased host response to implant-related infection in diabetic mice treated with the combination of a PGE₁ and antibiotic. In this group, restrained signs of infections were identified by micro-CT and histological analysis. On the other hand, the diabetic mice treated with the antibiotic alone showed a severe infection and inability to successfully respond to the standard antimicrobial treatment.

CONCLUSIONS

The present study revealed interesting preliminary results in the use of a drug combination of antibiotic and vasodilator to prevent implant-related Staphylococcus aureus infections in a diabetic mouse model.

Angiogenic efficacy of simplified 2-herb formula (NF3) in zebrafish embryos in vivo and rat aortic ring in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic foot ulceration results in high risk of lower extremity amputation, and represents a significant health care expenditure worldwide. Radix Astragali (RA) and Radix Rehmanniae (RR) are widely used Chinese medicinal herbs in treating diabetes, and have shown positive effects in enhancing wound healing in diabetic foot ulcer animal model.

MATERIALS AND METHODS

The angiogenic efficacy of NF3, a simplified 2-herb formula consisting of RA and RR in 2:1 ratio, was investigated. Median lethal concentration (LC50) and median effective concentration (EC50) were determined by treating zebrafish embryos with different concentrations of NF3 from 20 hpf to 72 hpf. The angiogenic activity of NF3 was examined in zebrafish embryos in vivo and by rat aortic ring assay in vitro. Cell cycle analysis of endothelial cells induced by NF3 was analyzed by flow cytometry using transgenic zebrafish Tg(fli1:EGFP). Real-time PCR was used to analyze mRNA expression profiles of selected genes involved in VEGF, FGF and MAPK pathways.

RESULTS

NF3 enhanced blood vessel formation as indicated by extra growth of intersegmental vessels in zebrafish embryos, and increased microvessels formation in rat aortic ring. NF3 also enhanced endothelial cells proliferation as shown by increased percentage of cells accumulating in S phase and G2/M phase of the cell cycle. NF3 exposure significantly induced up-regulation of VEGF-A, Flk-1, fgf1 and bRaf expression in zebrafish embryos.

CONCLUSIONS

Our results demonstrated that NF3 was effective in promoting angiogenesis in zebrafish embryos and by rat aortic ring assay, which provided scientific basis to support the use of NF3 as potential therapeutics in treating diabetic foot ulceration.

[Diabetic foot syndrome]

Diabetes mellitus contributes to a number of disorders that can affect the quality of life. Amongst this diabetic foot syndrome and diabetic foot ulceration are serious secondary complications of diabetes mellitus. Persons with diabetic foot ulceration have an increased risk of amputation. In the first part of this review the author focuses on the pathophysiology of diabetic foot ulceration. The second part covers the topics of current and future therapies. The reader will understand the need and modes for preventive measures, the importance of multi level education in this topic, and the need for specialized wound care centers. As emphasized by the author, diabetic foot syndrome and ulceration are serious complications of diabetes mellitus, which can lead to devastating lower-extremity amputations and possible death. Specialized wound care centers, multi level education and proper adherence to standard treatment regimes can potentially prevent the need for amputation.

The versatility of propeller flaps for lower limb reconstruction in patients with peripheral arterial obstructive disease: initial experience

In this study, we evaluate the feasibility of propeller flaps, for soft tissue reconstruction in patients with peripheral arterial obstructive disease (PAOD). Five patients (average age, 72 years old), presenting with necrosis of several foot units, were diagnosed with stage IV PAOD and diabetes mellitus. All underwent revascularization, followed by soft tissue reconstruction using propeller flaps. A total of 6 flaps were performed, with dimensions ranging from 4 x 7 cm to 8 x 31 cm. Perforator origin was the peroneal (5 flaps) or the tibial posterior artery (1 flap). Average operative time was 190 minutes. Overall patency was 83.3%; 1 case was complicated with total flap loss followed by below-knee amputation; 1 case developed partial necrosis necessitating skin grafting. All flaps developed mild postoperative edema, which resolved spontaneously. Propeller flaps prove to be useful tools for soft tissue reconstruction in patients with PAOD because of low operative morbidity, easy technique with fast learning curve, and low complications rate.

Phase I trial on the safety of topical rhVEGF on chronic neuropathic diabetic foot ulcers

OBJECTIVE

To assess the safety/tolerability and perform a preliminary efficacy evaluation of a multiple-dosing regimen of recombinant human vascular endothelial growth factor (VEGF165 or rhVEGF; telbermin) applied topically to chronic diabetic neuropathic foot ulcers.

METHOD

Subjects with type 1 or 2 diabetes mellitus were randomised to receive either topical applied telbermin (72 microg/cm2) (n=29) or placebo (n=26) treatment to the foot ulcer surface in conjunction with standard ulcer care. Subjects received treatment every 48 hours (maximum three doses per week) for up to six weeks. Weekly 35mm photography, quantitative planimetry and physical examinations documented the ulcer appearance, surface area and stage. Safety endpoints included incidence of clinically significant hypotension, adverse events and ulcer infection. Exploratory efficacy endpoints included percentage reduction in total ulcer surface area, incidence of complete ulcer healing and time to complete ulcer healing.

RESULTS

Incidence of adverse events was comparable in the two treatment groups. None of the adverse events were attributed to study drug, and no hypotension was observed as a result of telbermin treatment. Occurrence of infected study ulcers appeared to be balanced between the treatment groups. Positive trends suggestive of potential signals of biological activity were observed for incidence of complete ulcer healing (41.4% telbermin versus 26.9% placebo at day 43 [P=0.39]) and time to complete ulcer healing (25th percentile of 32.5 days telbermin versus 43.0 days placebo [log-rank P=0.13]).

CONCLUSION

The topical application of telbermin 72 microg/cm2 three times a week for up to six weeks appeared to be well tolerated. Further studies are required to characterise the safety/efficacy of telbermin more completely.

Compressed air massage hastens healing of the diabetic foot

BACKGROUND

The management of diabetic foot ulcers remains a problem. A treatment modality that uses compressed air massage has been developed as a supplement to standard surgical and medical treatment. Compressed air massage is thought to improve local tissue oxygenation around ulcers. The aim of this study was to determine whether the addition of compressed air massage influences the rate of healing of diabetic ulcers.

METHODS

Sixty consecutive patients with diabetes, admitted to one hospital for urgent surgical management of diabetic foot ulcers, were randomized into two groups. Both groups received standard medical and surgical management of their diabetes and ulcer. In addition, one group received 15-20 min of compressed air massage, at 1 bar pressure, daily, for 5 days a week, to the foot and the tissue around the ulcer. Healing time was calculated as the time from admission to the time of re-epithelialization.

RESULTS

Fifty-seven patients completed the trial; 28 received compressed air massage. There was no difference in the mean age, Wagner score, ulcer size, pulse status, or peripheral sensation in the two groups. The time to healing in the compressed air massage group was significantly reduced: 58.1 +/- 22.3 days (95% confidence interval: 49.5-66.6) versus 82.7 +/- 30.7 days (95% confidence interval: 70.0-94.3) (P = 0.001). No adverse effects in response to compressed air massage were noted.

CONCLUSIONS

The addition of compressed air massage to standard medical and surgical management of diabetic ulcers appears to enhance ulcer healing. Further studies with this new treatment modality are warranted.

The treatment of diabetic foot ulcers: reviewing the literature and a surgical algorithm

PURPOSE

To provide an overview of the literature related to the treatment of diabetic foot ulcers.

TARGET AUDIENCE

This continuing education activity is intended for physicians and nurses with an interest in wound care.

OBJECTIVES

After reading this article and taking this test, the reader should be able to:

Growth factors in the treatment of diabetic foot ulcers: new technologies, any promises?

Foot ulcers remain a common problem, leading to increased morbidity in patients with diabetes. Despite the progress that has been achieved in revascularization techniques as well as in off-loading to relieve high-pressure areas, diabetic foot wounds remain a clinical challenge. Growth factors are a major technological advance that promised to change the face of wound healing. The most important of growth factors are recombinant human platelet-derived growth factor-BB and granulocyte colony-stimulating factor. The former has been approved by the FDA for the treatment of neuropathic ulcers when there is adequate blood supply. The latter is less demonstrably useful. Advances include methods of delivering growth factors.

Treatment for diabetic foot ulcers

People with diabetes develop foot ulcers because of neuropathy (sensory, motor, and autonomic deficits), ischaemia, or both. The initiating injury may be from acute mechanical or thermal trauma or from repetitively or continuously applied mechanical stress. Patients with clinically significant limb ischaemia should be assessed by a vascular surgeon to determine the need for angioplasty, stenting, or femorodistal bypass. When infection complicates a foot ulcer, the combination can be limb or life-threatening. Infection is defined clinically, but wound cultures reveal the causative pathogens. Tissue specimens are strongly preferred to wound swabs for wound cultures. Antimicrobial therapy should be guided by culture results, and should aim to cure the infection, not to heal the wound. Alleviation of the mechanical load on ulcers (off-loading) should always be a part of treatment. Neuropathic ulcers typically heal in 6 weeks with total contact casting, because it effectively relieves pressure at the ulcer site and enforces patient compliance. The success of other approaches to off-loading similarly depends on the patients' adherence to the effectiveness of pressure relief. Surgery to heal ulcers and prevent recurrence can include tenotomy, tendon lengthening, reconstruction, or removal of bony prominences. However, these procedures may result in secondary ulceration and other complications. Ulcer recurrence rates are high, but appropriate education for patients, the provision of posthealing footwear, and regular foot care can reduce rates of re-ulceration.