New ulceration, new major amputation, and survival rates in diabetic subjects hospitalized for foot ulceration from 1990 to 1993: a 6.5-year follow-up

Transplanted artificial amnion membrane enhanced wound healing in third-degree burn injury diabetic mouse model

Introduction

Wound healing is severely compromised in patients with diabetes owing to factors such poor blood circulation, delayed immune response, elevated blood sugar levels, and neuropathy. Although the development of new wound healing products and prevention of serious complications such as infections in wounds have received substantial interest, wound healing remains a challenge in regenerative medicine. Burn wounds, especially third-degree burns, are difficult to treat because they are associated with immune and inflammatory reactions and distributive shock. Wound care and treatment that protects the burn site from infection and allows wound healing can be achieved with bioengineered wound dressings. However, few studies have reported effective dressings for third-degree burn wounds, making it important to develop new dressing materials.

Methods

In this study, we developed an artificial amniotic membrane (AM) using epithelial and mesenchymal cells derived from human amnion as a novel dressing material. The artificial AM was applied to the wound of a diabetic third-degree burn model and its wound healing ability was evaluated.

Results

This artificial amnion produced multiple growth factors associated with angiogenesis, fibroblast proliferation, and anti-inflammation. In addition, angiogenesis and granulation tissue formation were promoted in the artificial AM-treated mouse group compared with the control group. Furthermore, the inflammatory phase was prolonged in the control group.

Conclusions

Our preliminary results indicate that the artificial AM might be useful as a new dressing for refractory ulcers and third-degree burns. This artificial AM-based material represents great potential for downstream clinical research and treatment of diabetes patients with third-degree burns.

Long-term Results After Autologous Fat Transfer for Treatment of Chronic Lower Extremity Wounds

Autologous fat transfer may offer a simple and effective treatment option for chronic wound patients, delivering adipose-derived stem cells, with potent regenerative attributes. Nevertheless, the clinical benefit has not yet been sufficiently demonstrated. A total of 39 wound patients were treated with autologous fat transfer (AFT) and matched with a control group, according to the identified confounding variables "gender" and "method of defect closure." All data were acquired retrospectively. Primary outcome was "wound closure" and "reduction of wound size."After a follow-up of 48 weeks, there was no significant difference in primary outcome (wound closure P = .54) between both groups. The relative wound reduction after fat transfer was 69.9% ± 42.7% compared to 53.4% ± 106.8% in the control group (P = .91). Subgroup analysis of all patients, healed by secondary intention, revealed an increased wound size reduction (P = .03) and wound closure rate (P = .20) in the case group after 12 weeks. No adverse events were recorded. Fat grafting can reduce the wound size if left to secondary healing and may be considered individually for reconstructive purposes. A repeated application of autologous fat might be beneficial due to a temporary effect.

RIG-I contributes to keratinocyte proliferation and wound repair by inducing TIMP-1 expression through NF-κB signaling pathway

Epithelial keratinocyte proliferation is an essential element of wound repair, and chronic wound conditions, such as diabetic foot, are characterized by aberrant re-epithelialization. In this study, we examined the functional role of retinoic acid inducible-gene I (RIG-I), a key regulator of epidermal keratinocyte proliferation, in promoting TIMP-1 expression. We found that RIG-I is overexpressed in keratinocytes of skin injury and underexpressed in skin wound sites of diabetic foot and streptozotocin-induced diabetic mice. Moreover, mice lacking RIG-I developed an aggravated phenotype when subjected to skin injury. Mechanistically, RIG-I promoted keratinocyte proliferation and wound repair by inducing TIMP-1 via the NF-κB signaling pathway. Indeed, recombinant TIMP-1 directly accelerated HaCaT cell proliferation in vitro and promoted wound healing in Ddx58-/- and diabetic mice in vivo. In summary, we demonstrated that RIG-I is a crucial factor that mediates epidermal keratinocyte proliferation and may be a potential biomarker for skin injury severity, thus making it an attractive locally therapeutic target for the treatment of chronic wounds such as diabetic foot.

Diabetic retinopathy relates to the incidence of foot ulcers and amputations in type 2 diabetes

AIMS

We investigated whether Diabetic Retinopathy (DR) is related to Diabetic Foot Ulcer (DFU) development, adjusted for the stratification of the International Work Group on Diabetic Foot (IWGDF) guidance.

MATERIALS AND METHODS

DR and IWGDF stratification was registered retrospectively in patients hospitalised from 2009 to 2017 for uncontrolled and/or complicated type 2 diabetes. New DFUs were registered until 2020. Survival analyses categorised the subjects for DR, and multivariate Cox regression adjusted for confounders.

RESULTS

The 522 patients (57.9% male) were 62 ± 9 years old with a diabetes duration of 14 ± 10 years, HbA1c of 8.7 ± 1.8%, 33.9% macroangiopathies and 44.8% diabetic kidney diseases. Their grades of DFU risk were 0 for 43.3%, 1 for 23.9%, 2 for 7.1%, and 3 for 25.6%. During the 52 months follow-up (Inter Quartile Range: 32-71), 58 new DFUs and 18 lower-limb amputations occurred, mostly in patients with DR present in 140 (26.8%) patients. Adjusted for age, sex and conventional risk factors (duration and control of diabetes, arterial hypertension, and dyslipidemia), and other complications (macroangiopathy and diabetic kidney disease), DR was associated with a greater incidence of DFUs. Adjusted for the IWGDF classification, DR was related to new DFUs (HR: 2.51, 95%Confidence Interval [CI]: 1.48-4.26) and amputations (HR: 3.56, 95%CI: 1.26-10.07). This relationship persisted in ascending IWGDF grades with incidences of DFUs from 2/1000 (grade 0, no DR) to 121/1000 patient-years (grade 3 and DR) and amputations from 0 (grade 0, no DR) to 38/1000 patient-years (grade 3 and DR).

CONCLUSIONS

Diabetic retinopathy independently relates to the incidence of foot ulcers and amputations in patients hospitalised for type 2 diabetes.

Sarcopenia is an independent risk factor for all-cause mortality rate in patients with diabetic foot ulcers

Objective

This study aimed to determine whether sarcopenia affects the all-cause mortality rate of patients with diabetic foot ulcers (DFUs).

Research design and methods

The clinic-based observational study included 217 patients treated at the Department of Endocrinology, the First Affiliated Hospital of Chongqing Medical University during a 4-year period. All subjects underwent dual-energy X-ray absorptiometry to determine their body composition during hospitalization. Diagnosis of sarcopenia was based on the Baumgartner diagnostic criteria. Patients were followed up regularly by phone calls until April 1, 2019, and their survival status was recorded.Univariate and multivariate Cox risk ratio regression models were used to analyze factors influencing the all-cause mortality rate of patients with DFUs.

Results

Of the 217 patients, 158 people survived (82.7%), 33 died (17.3%), and 26 were lost to follow-up. The median follow-up time was 23 (Range 11-34) months. The majority of patients were male (68.6%), with a mean age of 67.29 ± 11.14 years. The 5-year survival rate was 68.3% and 45.9% for all study patients (n = 217) and sarcopenia patients (n = 81), respectively. Multivariate Cox risk regression model showed that age (HR 1.042[95%CI:1.006, 1.078], P = 0.021), sarcopenia (HR 5.051[95%CI:1.968, 12.961], P = 0.001), and serum creatinine (HR 1.007[95%CI: 1.003, 1.010], P < 0.001) were independent risk factors for all-cause mortality rate of patients with DFUs. Kaplan-Meier survival curve indicated that the survival rate of patients with sarcopenia was significantly lower than non-sarcopenia patients (P < 0.001).

Conclusions

Sarcopenia is an independent risk factor for all-cause mortality of patients with DFUs and hence an important prognostic factor for patients with DFUs. Active prevention and improvement of sarcopenia can potentially improve the survival outcomes of this patient population.

Balance of Macrophage Activation by a Complex Coacervate-Based Adhesive Drug Carrier Facilitates Diabetic Wound Healing

Uncontrolled and sustained inflammation disrupts the wound-healing process and produces excessive reactive oxygen species, resulting in chronic or impaired wound closure. Natural antioxidants such as plant-based extracts and natural polysaccharides have a long history in wound care. However, they are hard to apply to wound beds due to high levels of exudate or anatomical sites to which securing a dressing is difficult. Therefore, we developed a complex coacervate-based drug carrier with underwater adhesive properties that circumvents these challenges by enabling wet adhesion and controlling inflammatory responses. This resulted in significantly accelerated wound healing through balancing the pro- and anti-inflammatory responses in macrophages. In brief, we designed a complex coacervate-based drug carrier (ADC) comprising oligochitosan and inositol hexaphosphate to entrap and release antioxidant proanthocyanins (PA) in a sustained way. The results from in vitro experiments demonstrated that ADC is able to reduce LPS-stimulated pro-inflammatory responses in macrophages. The ability of ADC to reduce LPS-stimulated pro-inflammatory responses in macrophages is even more promising when ADC is encapsulated with PA (ADC-PA). Our results indicate that ADC-PA is able to polarize macrophages into an M2 tissue-healing phenotype via up-regulation of anti-inflammatory and resolution of inflammatory responses. Treatment with ADC-PA around the wound beds fine-tunes the balance between the numbers of inducible nitric oxide synthase-positive (iNOS+) and mannose receptor-negative (CD206-) M1 and iNOS-CD206+ M2 macrophages in the wound microenvironment compared to controls. Achieving such a balance between the numbers of iNOS+CD206- M1 and iNOS-CD206+ M2 macrophages in the wound microenvironment has led to significantly improved wound closure in mouse models of diabetes, which exhibit severe impairments in wound healing. Together, our results demonstrate for the first time the use of a complex coacervate-based drug delivery system to promote timely resolution of the inflammatory responses for diabetic wound healing by fine-tuning the functions of macrophages.

The Prognosis of Diabetic Foot Ulcer is Independent of age? A Comparative Analysis of the Characteristics of Patients with Diabetic Foot Ulcer in Different age Groups: A Cross-Sectional Study from China

Background: With younger onset age of type 2 diabetes mellitus (T2DM), the incidence of diabetic foot ulcer (DFU) in young and middle-aged adults is also increasing. Elucidating the distinctive characteristics of DFU in different ages and exploring the influence of age on the prognosis of DFU are crucial to the improvement of DFU treatments. Methods: 684 patients hospitalized for DFU in the department of endocrinology were recruited and assigned into the young and middle-aged group (age <65 years old) and the elderly group (age ≥65 years old). Demographic data and clinical features were compared between two groups. Results: Compared with the elderly group, the young and middle-aged group had higher proportion of males (72.3% vs 49.6%, P < .01) and smokers (52.5% vs 35.8%, P < .01), shorter duration of diabetes mellitus (155 months vs 196 months, P < .01), higher levels of glycosylated hemoglobin (9.3% vs 8.7%, P < .01), lower ratio of ankle-brachial index <0.9 (25.8% vs 51.1%, P < .01) and higher levels of c-reactive protein and erythrocyte sedimentation rate (14 mg/L vs 10 mg/L, P < .05; 36 mm/h vs 30 mm/h, P < .05). The prevalence of diabetic peripheral neuropathy and Wagner Grade were similar in two groups. Of note, the prognosis was similar in different age groups, as there were no significant differences in the healing rate (59.7% vs 60.1%, P > .05), healing time (30 days vs 22 days, P > .05) and minor amputation rate (11.9% vs 8.7%, P > .05). Conclusions: We found that no evidence to suggest a better prognosis with younger DFU patients. Compared with elderly ones, young and middle-aged patients were characterized by a higher proportion of smoking, worse glycemic control, higher inflammatory biomarkers but less severe lower limb ischemia, indicating that smoking cessation, strict blood glucose control and early detection of infection were crucial for improving the prognosis of young and middle-aged diabetic DFU patients.

The association between bacteria and outcome and the influence of sampling method, in people with a diabetic foot infection

Purpose

Different bacteria lead to divers diabetic foot infections (DFIs), and some bacteria probably lead to higher amputation and mortality risks. We assessed mortality and amputation risk in relation to bacterial profiles in people DFI and investigated the role of sampling method.

Methods

We included people (> 18 years) with DFI in this retrospective study (2011–2020) at a Dutch tertiary care hospital. We retrieved cultures according to best sampling method: (1) bone biopsy; (2) ulcer bed biopsy; and (3) swab. We aggregated data into a composite determinant, consisting of unrepeated bacteria of one episode of infection, clustered into 5 profiles: (1) Streptococcus and Staphylococcus aureus; (2) coagulase-negative Staphylococcus, Cutibacterium, Corynebacterium and Enterococcus; (3) gram-negative; (4) Anaerobic; and (5) less common gram-positive bacteria. We calculated Hazard Ratio’s (HR’s) using time-dependent-Cox regression for the analyses and investigated effect modification by sampling method.

Results

We included 139 people, with 447 person-years follow-up and 459 episodes of infection. Sampling method modified the association between bacterial profiles and amputation for profile 2. HR’s (95% CI’s) for amputation for bacterial profiles 1–5: 0.7 (0.39–1.1); stratified analysis for profile 2: bone biopsy 0.84 (0.26–2.7), ulcer bed biopsy 0.89 (0.34–2.3), swab 5.9*(2.9–11.8); 1.3 (0.78–2.1); 1.6 (0.91–2.6); 1.6 (0.58–4.5). HR’s (95% CI’s) for mortality for bacterial profiles 1–5: 0.89 (0.49–1.6); 0.73 (0.38–1.4); 2.6*(1.4–4.8); 1.1(0.58–2.2); 0.80(0.19–3.3).

Conclusions

In people with DFI, there was no association between bacterial profiles in ulcer bed and bone biopsies and amputation. Only in swab cultures, low-pathogenic bacteria (profile 2), were associated with a higher amputation risk. Infection with gram-negative bacteria was associated with a higher mortality risk. This study underlined the possible negative outcome of DFI treatment based on swabs cultures.

RJX Improves Wound Healing in Diabetic Rats

BACKGROUND

We recently reported the clinical safety profile of RJX, a well-defined intravenous GMP-grade pharmaceutical formulation of anti-oxidant and anti-inflammatory vitamins as active ingredients, in a Phase 1 study in healthy volunteers (ClinicalTrials.gov Identifier: NCT03680105) (Uckun et al., Front. Pharmacol. 11, 594321. 10.3389/fphar.2020.594321). The primary objective of the present study was to examine the effects of GMP-grade RJX on wound and burn injury healing in diabetic rats.

METHODS

In the present study, a rat model of T2DM was used that employs HFD in combination with a single injection of STZ intraperitoneally (i.p) at a moderate dose level (45 mg/kg). Anesthetized diabetic rats underwent full-thickness skin excision on the back or were subjected to burn injury via a heated brass probe and then started on treatments with normal saline (NS = vehicle) or RJX administered via intraperitoneal injections for three weeks.

FINDINGS

Notably, diabetic rats treated with the 1.25 mL/kg or 2.5 mL/kg RJX (DM+RJX groups) rapidly healed their wounds as fast as non-diabetic control rats. Inflammatory cell infiltration in the dermis along with fibrin and cell debris on the epithelial layer persisted for up to 14 days in the DM+NS group but not in RJX-treated groups. The histopathological score of wound healing on days 7 and 14 was better in diabetic rats treated with RJX than diabetic rats treated with NS and comparable to the scores for non-diabetic healthy rats consistent with an accelerated healing process. The residual wound area of RJX-treated rats was significantly smaller than that of NS-treated diabetic rats at each evaluation time point (P<0.001). The accelerating effect of RJX on diabetic wound healing was dose-dependent. We obtained similar results in the burn injury model. Our results demonstrate that RJX - at a dose level >10-fold lower than its clinical maximum tolerated dose (MTD) - accelerates the healing of excision wounds as well burn injury in diabetic rats.

Plantar Foot Ulcer Recurrence in Neuropathic Patients Undergoing Percutaneous Tendo-Achilles Lengthening

Equinus contracture carries 3- and 4-fold associations with diabetes and plantar foot ulceration, respectively. Percutaneous tendo-Achilles lengthening is a useful method to alleviate peak plantar pressure resulting from equinus. We aimed to evaluate the effectiveness of percutaneous tendo-Achilles lengthening and estimate the relative longevity of the approach in reducing ulcer recurrence. The medical records of patients with equinus contracture who underwent percutaneous tendo-Achilles lengthening from 2010 to 2017 were reviewed. Included patients presented with plantar ulcers and a gastroc-soleus equinus of any angle <10° of ankle dorsiflexion with the affected knee extended and flexed. Patients who received concomitant tendon lengthening procedures (including anterior tibial tendon or flexor digitorum longus) were excluded. Outcome measures included time to wound healing, time to ulcer recurrence, and development of transfer lesion. Ninety-one patients underwent percutaneous tendo-Achilles lengthening with subsequent pedal ulceration without concomitant procedures. A total of 69 (75.8%) patients had a plantar forefoot ulcer, 7 (7.7%) had midfoot ulcers, 5 (5.5%) had hindfoot ulcers, and 3 (3.3%) had ulcers in multiple locations. Seven patients received prophylactic tendo-Achilles lengthening. At a mean follow-up of 31.6 months (±26), 66 (78.6%) wounds healed at a median 12.9 weeks. A total of 29 patients (43.9%) experienced ulcer recurrence at a mean of 12 months. Twelve patients (13%) experienced a transfer lesion at a mean of 16.6 months. Tendo-Achilles lengthening can be an effective adjunctive approach to achieve wound healing and reduce long-term ulcer recurrence in patients with equinus contracture and neuropathic plantar foot ulcers. A relengthening procedure may be needed within approximately 12 months from index surgery.

Re-amputation and survival following toe amputation: outcome data from a tertiary referral centre

PURPOSE

Toe amputation is a commonly performed procedure for irreversible foot sepsis. However, outcome and predictors of outcome are poorly understood. Our aim was to determine survival and rate of progression to further amputation following index toe amputation.

METHODS

Consecutive patients between 2010 and 2015 were included. Progression to further minor amputation, major amputation or death was recorded. Multivariable Cox regression analyses were undertaken to determine independent predictors of outcome and survival.

RESULTS

One hundred forty-six patients were included, with mean age of 65 years. Fifty-five (37.7%) patients underwent hallux amputation, while 91 (62.3%) underwent amputation of non-hallux digit(s). Following index toe amputation, 63 (43.2%) patients progressed to further minor or major ipsilateral amputation, median time to which was 36 months. Twenty-one patients (14.4%) progressed to major ipsilateral amputation. Patients undergoing index non-hallux amputation were significantly more likely to require further minor amputation (P = 0.050); however, the rate of major amputation between hallux (14.5%) and non-hallux (14.3%) groups was similar. Overall, 5-year ipsilateral amputation-free (iAFS) was 39.6 ± 4.1%, ipsilateral major amputation-free (iMAFS) was 55.9 ± 4.1% and overall survival (OS) was 64.3 ± 4.0% and did not differ between index amputation sites.

CONCLUSION

Almost half of patients undergoing toe amputation required further digital amputation. However, limb preservation rates are high, and a majority of patients are alive at 5-year follow-up. There was no significant difference in outcome between patients undergoing hallux and non-hallux primary procedures. Overall, increasing age remains the only independent predictor of iMAFS and OS.

The impact of gender on diabetes-related lower extremity amputations: An Italian regional analysis on trends and predictors

BACKGROUND

Diabetes-related lower extremity amputations (LEAs) are a major public health issue. The aim of the study was to evaluate trends by gender and predictors of LEAs in an Italian region.

METHODS

Data were collected from hospital discharge records between 2006 and 2015. Gender- and age-adjusted standardised hospitalisation rates for major and minor amputations were calculated. Poisson regression model was performed to estimate trends in LEAs.

RESULTS

Hospitalisation rates decreased for minor amputations both among males (-30.0%) and females (-5.3%), while the major amputation rates decreased only for males (-44.7%). Males were at higher risk of undergoing major (IRR 1.41, 95%CI 1.19-1.67) and minor (IRR 1.62, 95%CI 1.45-1.82) amputations. Peripheral vascular disease was the leading predictor of major and minor amputations.

CONCLUSION

A significant reduction of LEAs was observed only for males. Identifying their predictable factors may help caregivers to provide higher standards of diabetes care.

A meta-analysis of mortality after minor amputation among patients with diabetes and/or peripheral vascular disease

OBJECTIVE

Foot complications in patients with diabetes or peripheral artery disease (PAD) are serious events in the life of these patients that often lead to amputations and mortality. No evidence synthesis has been reported on the mortality rates after minor lower extremity amputation; thus, a quantitative evidence synthesis was needed.

METHODS

A systematic literature search was performed to identify studies that had reported the survival or mortality rates after a minor LEA. The studies were required to include one or more of the following primary outcomes: mortality rate at 30 days, 1 year, 3 years, 5 years, 6 to 7 years, or 8 to 9 years. The secondary outcomes were the mortality rates according to the anatomic location of the amputation in the foot and the independent risk factors for mortality.

RESULTS

A total of 28 studies with 17,325 subjects fulfilled the inclusion criteria. The meta-analytical results of the mortality rates were as follows: 3.5% at 1 month, 20% at 1 year, 28% at 3 years, 44.1% at 5 years, 51.3% at 6 to 7 years, and 58.5% at 8 to 9 years. From these studies of diabetic patients, age was the most consistent independent risk factor, followed by chronic kidney disease, PAD, and coronary artery disease. One study of patients with PAD had reported diabetes as an independent risk factor for mortality. The subgroup analysis of the four studies reporting the outcomes of patients with PAD showed greater 3- and 5-year mortality rates compared with the overall and "diabetic" results.

CONCLUSIONS

Mortality after minor amputation for patients with diabetes and/or PAD was found to be very high. Compared with the reported cancer data, survival was worse than that for many cancers. Just as in the case of major amputations, minor amputations should be considered a pivotal event in the life of these patients.

Effectiveness of psychosocial interventions for the prevention and treatment of foot ulcers in people with diabetes: a systematic review

AIM

To identify and synthesize the evidence for the effectiveness of psychosocial interventions to promote the healing, and/or reduce the occurrence of, foot ulceration in people with diabetes.

METHODS

In March 2019 we searched CENTRAL, Medline, Embase and PsycInfo for randomized controlled trials of interventions with psychosocial components for people with diabetes. The primary outcomes of this review were foot ulceration and healing. We assessed studies using the Cochrane risk-of-bias tool, the TIDieR checklist and GRADE. We conducted narrative synthesis and random-effects meta-analysis.

RESULTS

We included 31 randomized controlled trials (4511 participants), of which most (24 randomized controlled trials, 4093 participants) were prevention studies. Most interventions were educational with a modest psychosocial component. Ulceration and healing were not reported in most studies; secondary outcomes varied. Evidence was of low or very low quality because of high risks of bias and imprecision, and few studies reported adherence or fidelity. In groups where participants had prior ulceration, educational interventions had no clear effect on new ulceration (low-quality evidence). Two treatment studies, assessing continuous pharmacist support and an intervention to promote understanding of well-being, reported healing but their evidence was also of very low quality.

CONCLUSION

Most psychosocial intervention randomized controlled trials assessing foot ulcer outcomes in people with diabetes were prevention studies, and most interventions were primarily educational. Ulcer healing and development were not well reported. There is a need for better understanding of psychological and behavioural influences on ulcer incidence, healing and recurrence in people with diabetes. Randomized controlled trials of theoretically informed interventions, which assess clinical outcomes, are urgently required. (PROSPERO registration: CRD42016052960).

Psychosocial and behavioural prognostic factors for diabetic foot ulcer development and healing: a systematic review

AIM

To investigate whether ulceration, amputation and healing of foot ulcers in people living with diabetes are associated with psychosocial and behavioural factors.

METHODS

We searched MEDLINE, Embase, PsychINFO, CINAHL and The Cochrane Library to March 2019 for longitudinal studies with multivariable analyses investigating independent associations. Two reviewers extracted data and assessed risk of bias.

RESULTS

We identified 15 eligible studies involving over 12 000 participants. Clinical and methodological heterogeneity precluded meta-analysis, so we summarize narratively. Risk of bias was moderate or high. For ulceration, we found significantly different results for people with and without an ulcer history. For those with no ulcer history, moderate quality evidence suggests depression increases ulcer risk [three studies; e.g. hazard ratio (HR) 1.68 (1.20, 2.35) per Hospital Anxiety and Depression Scale (HADS) standard unit]. Better foot self-care behaviour reduces ulcer risk [HR 0.61 (0.40, 0.93) per Summary of Diabetes Self-Care Activities scale standard unit; one study]. For people with diabetes and previous ulcers, low- or very low-quality evidence suggests little discernible association between ulcer recurrence and depression [e.g. HR 0.88 (0.61, 1.27) per HADS standard unit], foot self-care, footwear adherence or exercise. Low-quality evidence suggests incomplete clinic attendance is strongly associated with amputation [odds ratio (OR) 3.84 (1.54, 9.52); one study]. Evidence for the effects of other psychosocial or behavioural factors on ulcer healing and amputation is very low quality and inconclusive.

CONCLUSIONS

Psychosocial and behavioural factors may influence the development of first ulcers. More high quality research is needed on ulcer recurrence and healing. (Open Science Framework Registration: https://osf.io/ej689).

Survival and factors predicting mortality after major and minor lower-extremity amputations among patients with diabetes: a population-based study using health information systems

INTRODUCTION

The aim of the study was to identify the sociodemographic and clinical factors associated with death after the first lower-extremity amputation (LEA), minor and major separately, using data from regional health administrative databases.

RESEARCH DESIGN AND METHODS

We carried out a population-based cohort study including patients with diabetes residing in the Lazio region and undergoing a primary amputation in the period 2012-2015. Each individual was followed up for at least 2 years. Kaplan-Meier analysis was used to evaluate long-term survival; Cox proportional regression models were applied to identify factors associated with all-cause mortality.

RESULTS

The cohort included 1053 patients, 72% were male, 63% aged ≥65 years, and 519 (49%) died by the end of follow-up. Mortality rates at 1 and 4 years were, respectively, 33% and 65% for major LEA and 18% and 45% for minor LEA. Significant risk factors for mortality were age ≥65, diabetes-related cardiovascular complications, and chronic renal disease for patients with minor LEA, and age ≥75 years, chronic renal disease and antidepressant drug consumption for subjects with major LEA.

CONCLUSIONS

The present study confirms the high mortality rates described in patients with diabetes after non-traumatic LEA. It shows differences between minor and major LEA in terms of mortality rates and related risk factors. The study highlights the role of depression as specific risk factor for death in patients with diabetes after major LEA and suggests including its definition and management in strategies to reduce the high mortality rate observed in this group of patients.

Epigenetic Regulation of TLR4 in Diabetic Macrophages Modulates Immunometabolism and Wound Repair

Macrophages are critical for the initiation and resolution of the inflammatory phase of wound healing. In diabetes, macrophages display a prolonged inflammatory phenotype preventing tissue repair. TLRs, particularly TLR4, have been shown to regulate myeloid-mediated inflammation in wounds. We examined macrophages isolated from wounds of patients afflicted with diabetes and healthy controls as well as a murine diabetic model demonstrating dynamic expression of TLR4 results in altered metabolic pathways in diabetic macrophages. Further, using a myeloid-specific mixed-lineage leukemia 1 (MLL1) knockout (Mll1^f/fLyz2^Cre+ ), we determined that MLL1 drives Tlr4 expression in diabetic macrophages by regulating levels of histone H3 lysine 4 trimethylation on the Tlr4 promoter. Mechanistically, MLL1-mediated epigenetic alterations influence diabetic macrophage responsiveness to TLR4 stimulation and inhibit tissue repair. Pharmacological inhibition of the TLR4 pathway using a small molecule inhibitor (TAK-242) as well as genetic depletion of either Tlr4 (Tlr4^-/- ) or myeloid-specific Tlr4 (Tlr4^f/fLyz2^Cre+) resulted in improved diabetic wound healing. These results define an important role for MLL1-mediated epigenetic regulation of TLR4 in pathologic diabetic wound repair and suggest a target for therapeutic manipulation.

The Histone Methyltransferase Setdb2 Modulates Macrophage Phenotype and Uric Acid Production in Diabetic Wound Repair

Macrophage plasticity is critical for normal tissue repair to ensure transition from the inflammatory to the proliferative phase of healing. We examined macrophages isolated from wounds of patients afflicted with diabetes and of healthy controls and found differential expression of the methyltransferase Setdb2. Myeloid-specific deletion of Setdb2 impaired the transition of macrophages from an inflammatory phenotype to a reparative one in normal wound healing. Mechanistically, Setdb2 trimethylated histone 3 at NF-κB binding sites on inflammatory cytokine gene promoters to suppress transcription. Setdb2 expression in wound macrophages was regulated by interferon (IFN) β, and under diabetic conditions, this IFNβ-Setdb2 axis was impaired, leading to a persistent inflammatory macrophage phenotype in diabetic wounds. Setdb2 regulated the expression of xanthine oxidase and thereby the uric acid (UA) pathway of purine catabolism in macrophages, and pharmacologic targeting of Setdb2 or the UA pathway improved healing. Thus, Setdb2 regulates macrophage plasticity during normal and pathologic wound repair and is a target for therapeutic manipulation.

A review on diabetic foot challenges in Guyanese perspective

BACKGROUND

Diabetes mellitus signifies a major public health threat worldwide. Type 2 diabetes has been reported as the fourth leading cause of death and has affected 15.5% of the adult population in Guyana, South America. Diabetes has also led to major lower extremity amputation at the only referral public hospital in Guyana. Diabetic foot and related complications are known to be multifactorial.

CONCLUSION

In this review, we highlight the information on the diabetic foot and related complications with an emphasis on Guyanese background.

Mortality in patients with diabetic foot ulcer: a retrospective study of 513 cases from a single Centre in the Northern Territory of Australia

BACKGROUND

Diabetic foot ulcers (DFU) are a common problem in longstanding diabetes. However, mortality outcomes in Australian patients with DFU are still unclear.

METHODS

All patients with DFU presenting for the first time to the Multi-Disciplinary Foot Clinic (MDFC) at Royal Darwin Hospital, Northern Territory Australia, between January 2003 and June 2015 were included in this study. These patients were followed until 2017, or death. Individual patient data was extracted from hospital and primary care information systems. Kaplan-Meier survival curves were developed. The association between various risk factors and mortality was analysed using Cox regression.

RESULTS

In total 666 subjects were screened, and 513 were included in the final analysis. Of these subjects, 247 were Indigenous and 266 were non-Indigenous. The median follow-up period was 5.8 years (IQR, 3.1-9.8). The mean age at inclusion was 59.9 ± 12.3 years and 62.8% were males. The majority (93.6%) had type 2 diabetes and the median diabetes duration was 7 years (IQR, 3-12). There were 199 deaths, with a 5-year-mortality rate of 24.6%, and a 10-year-mortality rate of 45.4%. The mean age at death was 64.6 ± 11.8 years. In a multivariate analysis, the following variables were associated with mortality (adjusted HR, 95% CI): age 1.04 (1.02-1.05, P < 0.001); chronic kidney disease 1.22 (1.11-1.33, P < 0.001), and plasma albumin 0.96 (0.94-0.99, P < 0.05). The most common causes of death were chronic kidney disease (24.6%), cardiovascular events (19.6%), sepsis (15.6%), respiratory failure (10.0%), malignancy (9.5%) and multi-organ failure (5.0%).

CONCLUSION

Patients with DFU have high mortality. Age, chronic kidney disease, and low albumin levels increase the risk of mortality. Strategies should focus on ulcer prevention and aggressive risk factor reduction.

Lipid nanoparticles silence tumor necrosis factor α to improve wound healing in diabetic mice

Diabetes mellitus is a mounting concern in the United States, as are the mortality and morbidity that result from its complications. Of particular concern, diabetes patients frequently suffer from impaired wound healing and resultant nonhealing diabetic foot ulcers. These ulcers overproduce tumor necrosis factor α (TNFα), which reduces wound bed cell migration and proliferation while encouraging apoptosis. Herein, we describe the use of siRNA-loaded lipid nanoparticles (LNPs) as a potential wound treatment to combat an overzealous immune response and facilitate wound closure. LNPs were formulated with an ionizable, degradable lipidoid and siRNA specific for TNFα. Topical application of nanoparticles reduced TNFα mRNA expression in the wound by 40-55% in diabetic and nondiabetic mice. In diabetic mice, this TNFα knockdown accelerated wound healing compared to untreated controls. Together, these results serve as proof-of-concept that RNA interference therapy using LNPs can reduce the severity and duration of chronic diabetic wounds.

Diabetic foot management: multidisciplinary approach for advanced lesion rescue

The diabetic foot is a complication of diabetes affecting 15% of diabetics in their lives. It is associated to diabetic neuropathy and peripheral vascular disease and its incidence has increased. The ulceration is the initial cause of a dramatic process leading, if not correctly treated, to amputations. Both neuropathy, neuro-ischemia and infections have a role in determining healing or worsening of the lesions and 85% of all amputations in diabetic patients are preceded by a foot ulceration deteriorating to a severe gangrene or infection. The different causative agents and the different clinical presentations of diabetic foot ask a multidisciplinary approach in order to address treatments to the final goals, the prevention of the amputations and the maintenance of a functional foot able with weight-bearing ability. Many professional figures, diabetologists, surgeons (both general and vascular and orthopedics), interventional radiologists, infectious diseases specialists, specialized nurses, podiatrists, orthotic technicians, are called to apply their knowledges to the diabetic patients affected by diabetic foot in a virtuous circle leading to reach the goals, with the imperative action of the multidisciplinary team. The so organized center will allow both a correct and rapid diagnosis, the use in ambulatorial environments of modern tools, or the hospitalization in multitasking wards, in which all the complications and the necessary treatments are possible, both in emergencies or in elective way, considering both revascularizations and surgery.

Ly6CHi Blood Monocyte/Macrophage Drive Chronic Inflammation and Impair Wound Healing in Diabetes Mellitus

OBJECTIVE

Wound monocyte-derived macrophage plasticity controls the initiation and resolution of inflammation that is critical for proper healing, however, in diabetes mellitus, the resolution of inflammation fails to occur. In diabetic wounds, the kinetics of blood monocyte recruitment and the mechanisms that control in vivo monocyte/macrophage differentiation remain unknown.

APPROACH AND RESULTS

Here, we characterized the kinetics and function of Ly6C^Hi [Lin^- (CD3^-CD19^-NK1.1^-Ter-119^-) Ly6G^-CD11b⁺] and Ly6C^Lo [Lin^- (CD3^-CD19^-NK1.1^-Ter-119^-) Ly6G^-CD11b⁺] monocyte/macrophage subsets in normal and diabetic wounds. Using flow-sorted tdTomato-labeled Ly6C^Hi monocyte/macrophages, we show Ly6C^Hi cells transition to a Ly6C^Lo phenotype in normal wounds, whereas in diabetic wounds, there is a late, second influx of Ly6C^Hi cells that fail transition to Ly6C^Lo. The second wave of Ly6C^Hi cells in diabetic wounds corresponded to a spike in MCP-1 (monocyte chemoattractant protein-1) and selective administration of anti-MCP-1 reversed the second Ly6C^Hi influx and improved wound healing. To examine the in vivo phenotype of wound monocyte/macrophages, RNA-seq-based transcriptome profiling was performed on flow-sorted Ly6C^Hi [Lin^-Ly6G^-CD11b⁺] and Ly6C^Lo [Lin^-Ly6G^-CD11b⁺] cells from normal and diabetic wounds. Gene transcriptome profiling of diabetic wound Ly6C^Hi cells demonstrated differences in proinflammatory and profibrotic genes compared with controls.

CONCLUSIONS

Collectively, these data identify kinetic and functional differences in diabetic wound monocyte/macrophages and demonstrate that selective targeting of CD11b⁺Ly6C^Hi monocyte/macrophages is a viable therapeutic strategy for inflammation in diabetic wounds.

Prognosis of the infected diabetic foot ulcer: a 12-month prospective observational study

AIMS

To determine clinical outcomes and explore prognostic factors related to ulcer healing in people with a clinically infected diabetic foot ulcer.

METHODS

This multicentre, prospective, observational study reviewed participants' data at 12 months after culture of a diabetic foot ulcer requiring antibiotic therapy. From participants' notes, we obtained information on the incidence of wound healing, ulcer recurrence, lower extremity amputation, lower extremity revascularization and death. We estimated the cumulative incidence of healing at 6 and 12 months, adjusted for lower extremity amputation and death using a competing risk analysis, and explored the relationship between baseline factors and healing incidence.

RESULTS

In the first year after culture of the index ulcer, 45/299 participants (15.1%) had died. The ulcer had healed in 136 participants (45.5%), but recurred in 13 (9.6%). An ipsilateral lower extremity amputation was recorded in 52 (17.4%) and revascularization surgery in 18 participants (6.0%). Participants with an ulcer present for ~2 months or more had a lower incidence of healing (hazard ratio 0.55, 95% CI 0.39 to 0.77), as did those with a PEDIS (perfusion, extent, depth, infection, sensation) perfusion grade of ≥2 (hazard ratio 0.37, 95% CI 0.25 to 0.55). Participants with a single ulcer on their index foot had a higher incidence of healing than those with multiple ulcers (hazard ratio 1.90, 95% CI 1.18 to 3.06).

CONCLUSIONS

Clinical outcomes at 12 months for people with an infected diabetic foot ulcer are generally poor. Our data confirm the adverse prognostic effect of limb ischaemia, longer ulcer duration and the presence of multiple ulcers.

Inverse Relationship Between Serum Bilirubin Levels and Diabetic Foot in Chinese Patients with Type 2 Diabetes Mellitus

BACKGROUND Several studies demonstrated that bilirubin, a potent endogenous antioxidant, is a strong protective factor for many diabetic complications such as nephropathy, retinopathy, neuropathy, and vasculopathy. The purpose of this study was to assess the association between serum bilirubin levels and diabetic foot (DF) in Chinese patients with type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS The present cross-sectional study of bilirubin levels in relation to DF was conducted in 1,269 T2DM patients with (n=578) and without (n=691) DF. Blood test results were obtained on hospital admission, including total bilirubin (T-BIL), direct bilirubin (D-BIL), and indirect bilirubin (I-BIL). Data on Wagner classification and amputation procedure in patients with DF were collected by reviewing electronic medical records. Univariate or multivariate analysis were performed to explore the association between bilirubin and DF. RESULTS Serum I-BIL levels were shown to play a protective role regarding the presence and severity of DF (OR=0.75, p=0.029 and OR=0.90, p=0.021, respectively). In addition, in a comparison of the lowest and highest tertiles of serum bilirubin concentration, the highest tertile of serum T-BIL (OR=0.51, p=0.011) and I-BIL (OR=0.28, p<0.001) was significantly related with a lower Wagner grade of DF. Patients with DF in the highest tertiles of T-BIL carried a significantly lower risk of amputation events than those in the lowest tertiles (OR=0.47, p=0.025). CONCLUSIONS The present study provided evidence that decreased serum bilirubin levels were independently associated with the presence and severity of DF and amputation events in patients with DF.

The Histone Methyltransferase MLL1 Directs Macrophage-Mediated Inflammation in Wound Healing and Is Altered in a Murine Model of Obesity and Type 2 Diabetes

Macrophages are critical for the initiation and resolution of the inflammatory phase of wound repair. In diabetes, macrophages display a prolonged inflammatory phenotype in late wound healing. Mixed-lineage leukemia-1 (MLL1) has been shown to direct gene expression by regulating nuclear factor-κB (NF-κB)-mediated inflammatory gene transcription. Thus, we hypothesized that MLL1 influences macrophage-mediated inflammation in wound repair. We used a myeloid-specific Mll1 knockout (Mll1^f/fLyz2^Cre+ ) to determine the function of MLL1 in wound healing. Mll1^f/fLyz2^Cre+ mice display delayed wound healing and decreased wound macrophage inflammatory cytokine production compared with control animals. Furthermore, wound macrophages from Mll1^f/fLyz2^Cre+ mice demonstrated decreased histone H3 lysine 4 trimethylation (H3K4me3) (activation mark) at NF-κB binding sites on inflammatory gene promoters. Of note, early wound macrophages from prediabetic mice displayed similarly decreased MLL1, H3K4me3 at inflammatory gene promoters, and inflammatory cytokines compared with controls. Late wound macrophages from prediabetic mice demonstrated an increase in MLL1, H3K4me3 at inflammatory gene promoters, and inflammatory cytokines. Prediabetic macrophages treated with an MLL1 inhibitor demonstrated reduced inflammation. Finally, monocytes from patients with type 2 diabetes had increased Mll1 compared with control subjects without diabetes. These results define an important role for MLL1 in regulating macrophage-mediated inflammation in wound repair and identify a potential target for the treatment of chronic inflammation in diabetic wounds.

Recent advances in biomaterials for the treatment of diabetic foot ulcers

Diabetes mellitus is one of the most challenging epidemics facing the world today, with over 300 million patients affected worldwide.

Anti-Inflammatory Effects of Rosiglitazone in Obesity-Impaired Wound Healing Depend on Adipocyte Differentiation

Combined diabetes-obesity syndromes severely impair regeneration of acute skin wounds in mouse models. This study assessed the contribution of subcutaneous adipose tissue to exacerbated wound inflammatory conditions. Genetically obese (ob/ob) mice showed an increased expression of positive transcriptional effectors of adipocyte differentiation such as Krüppel-like factor (KLF)-5 and peroxisome proliferator-activated receptor (PPAR)-γ and an associated expression of leptin and fatty acid-binding protein (FABP)-4, but also CXCL2 in isolated subcutaneous fat. This observation in obese mice is in keeping with differentially elevated levels of KLF-5, PPAR-γ, leptin, FABP-4 and CXCL2 in in vitro-differentiated 3T3-L1 adipocytes. Notably, CXCL2 expression restrictively appeared upon cytokine (IL-1β/TNF-α) stimulation only in mature, but not immature 3T3-L1 adipocytes. Of importance, the critical regulator of adipocyte maturation, PPAR-γ, was merely expressed in the final phase of in-vitro induced adipocyte differentiation from 3T3-L1 pre-adipocytes. Consistently, the PPAR-γ agonist rosiglitazone suppressed cytokine-induced CXCL2 release from mature adipocytes, but not from early 3T3-L1 adipocyte stages. The inhibitory effect of PPAR-γ activation on CXCL2 release appeared to be a general anti-inflammatory effect in mature adipocytes, as cytokine-induced cyclooxygenase (Cox)-2 was simultaneously repressed by rosiglitazone. In accordance with these findings, oral administration of rosiglitazone to wounded obese mice significantly changed subcutaneous adipocyte morphology, reduced wound CXCL2 and Cox-2 expression and improved tissue regeneration. Thus, our data suggest that PPAR-γ might provide a target to suppress inflammatory signals from mature adipocytes, which add to the prolonged wound inflammation observed in diabetes-obesity conditions.

Diabetes Nurse Educators' Prioritized Elder Foot Care Behaviors

Purpose

The purpose of this study was to identify diabetes nurse educators' perceptions of the most important foot care behaviors for elderly people to enact in daily care.

Methods

A structured, open-ended questionnaire was mailed to a regionally stratified random sample of 90 diabetes nurse educators. Subjects were asked to identify and rank order 8 foot care behaviors perceived important for elderly people with diabetes to enact daily. Data were transcribed and coded into categories and domains using descriptive content analysis.

Results

Forty-seven diabetes nurse educators responded with a total of 346 foot care behaviors perceived important for elders. Twenty-one major foot care behavior content categories were grouped into 4 domains of descending importance: foot/nail care, footwear/shoes, general health, and foot emergencies.

Conclusions

Diabetes nurse educators generated a range of baseline data for developing a reliable, valid, and patient foot care knowledge outcome measure to support national diabetes patient education and self-management program guidelines.

Long-term mortality after lower-limb amputation

BACKGROUND

Mortality after amputation is known to be extremely high and is associated with a number of patient features. We wished to calculate this mortality after first-time lower-limb amputation and investigate whether any population or treatment factors are associated with worse mortality.

OBJECTIVE

To follow up individuals after lower limb amputation and ascertain the mortality rate as well as population or treatment features associated with mortality.

STUDY DESIGN

A prospective cohort study.

METHODS

Prospective lower-limb amputations over 1 year (N = 105) at a Regional Rehabilitation Centre were followed up for 3 years.

RESULTS

After 3 years, 35 individuals in the cohort had died, representing a mortality of 33%. On initial univariate analysis, those who died were more likely to have diabetes mellitus (χ(2) = 7.16, df = 1, p = 0.007) and less likely to have been fitted with a prosthesis (χ(2) = 5.84, df = 1, p = 0.016). There was no association with age, gender, level of amputation, social isolation, significant medical co-morbidity other than diabetes or presence of mood disorders. A multi-variable logistic regression (backward step) confirmed that diabetes (odds ratio = 3.04, confidence intervals = 1.25-7.40, p = 0.014) and absence of prosthesis-fitting (odds ratio = 2.60, confidence interval = 1.16-6.25, p = 0.028) were independent predictors of mortality.

CONCLUSION

Mortality after amputation is extremely high and is increased in individuals with diabetes or in those who are not fitted with a prosthesis after amputation.

CLINICAL RELEVANCE

The link between diabetes and mortality after amputation has been noted by others, but this is the first study to find an effect from prosthetic limb-wearing. This requires further investigation to ascertain why the wearing of a prosthetic limb, confers an independent survival benefit that is not related to the presence of medical co-morbidity.

Brachial-ankle pulse wave velocity, but not ankle-brachial index, predicts all-cause mortality in patients with diabetes after lower extremity amputation

We examined whether brachial‐ankle pulse wave velocity (baPWV) and ankle‐brachial pressure index (ABI) are predictors for mortality in diabetic patients after lower extremity amputation. This was an observational historical cohort study of 102 Japanese diabetic patients after first non‐traumatic lower extremity amputation, with a mean age of 63 years (standard deviation 12 years). The end‐point was all‐cause mortality. During the mean follow‐up period of 3.3 years, 44 patients reached the end‐point. In both univariate and multivariate analyses, baPWV (m/s) (hazard ratio [HR] 1.05 and 1.04, both P < 0.01, respectively), but not ABI (HR 0.38 and 0.89, P = 0.08 and 0.86, respectively), was a significant predictor for the end‐point. When baPWV (above or below the median [21.8 m/s]) and ABI (normal [0.9–1.4] or not) were analyzed as categorical variables, the results were similar. In conclusion, baPWV, but not ABI, might be a predictor for all‐cause mortality in diabetic patients after lower extremity amputation.

Survival evaluation of the patients with diabetic major lower-extremity amputations

PURPOSE

The purpose of this study was to evaluate the survival after major lower-limb amputation, at a level either below (BKA) or above (AKA) the knee, in diabetic patients.

METHODS

A total of 140 diabetic patients who underwent major lower-limb amputation during the period of 2001-2011 were enrolled in the study. The patients were grouped as below-knee and above-knee amputations. The differences in survival by age, gender, amputation level and revision surgery were investigated. The clinical follow-up periods and the results of the patients with major lower-limb amputation were retrospectively assessed.

RESULTS

The mean follow-up period was 24.87 months (range 0.06-120 months). The mortality rate of series was 32.8 % for 1 year and 70 % for 5 years. One-year mortality rate was 24.6 % and 5-year mortality rate was 66.3 % in below-knee group, 1-year mortality rate was 43.3 % and 5-year mortality rate was 83.3 % in above-knee group. The difference between mortality rates of these groups was significant (p: 0.019). There was no statistically significant difference according to age and gender (p: 0.543 and 0.568). The previous minor amputations were found to have no effect on mortality (p: 0.471).

CONCLUSION

Routine utilization of diabetes follow-up, screening and treatment programs with a multidisciplinary approach might be mandatory to handle early multisystem involvement-prevent major amputation, and increase survival rate in diabetic patients.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Prospective study on microangiopathy in type 2 diabetic foot ulcer

AIMS/HYPOTHESIS

We investigated the significance of microangiopathy in the development of foot ulcer, which is still disputed.

METHODS

We assessed microangiopathy by histological analysis of the capillary ultrastructure using transmission electron microscopy and capillary density and arteriolar morphology in paraffin-embedded sections from the skin of type 2 diabetic patients: 30 neuroischaemic patients (Isc) revascularised with peripheral angioplasty and 30 neuropathic patients (Neu) with foot ulcer, compared with ten non-diabetic volunteers.

RESULTS

In the diabetic patients, capillaries in the dermal papillary layer were fewer (-22.2%, 159 ± 43 vs 205 ± 52 mm(2) in non-diabetic volunteers, p < 0.01). They also showed detrimental remodelling, with a 2.2-fold increase in capillary basement membrane thickness (3.44 ± 1.19 vs 1.53 ± 0.34 μm in non-diabetic volunteers, p < 0.001) and a 57.7% decrease in lumen area (14.6 ± 11.1 vs 34.7 ± 27.5 μm(2), p < 0.001). No differences were observed between the diabetic Isc or Neu patients. Isc were more prone to develop arteriolar occlusion than Neu (16.8 ± 6.9% vs 6.7 ± 3.7%, respectively, p < 0.001). No patient had been amputated at 30 days and healing time was significantly longer in Isc (180 ± 120 vs 64 ± 50 days in Neu, p < 0.001).

CONCLUSIONS/INTERPRETATION

Capillary microangiopathy is present in equal measure in neuroischaemic and neuropathic diabetic foot skin. The predominance of arteriolar occlusions with neuroischaemia indicated the existence of an additional 'small vessel disease' that did not affect an effective revascularisation and did not worsen the prognosis of major amputations but slowed the healing process of the neuroischaemic foot ulcer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02610036.

The Hospitalization Costs of Diabetes and Hypertension Complications in Zimbabwe: Estimations and Correlations

Objective. Treating complications associated with diabetes and hypertension imposes significant costs on health care systems. This study estimated the hospitalization costs for inpatients in a public hospital in Zimbabwe. Methods. The study was retrospective and utilized secondary data from medical records. Total hospitalization costs were estimated using generalized linear models. Results. The median cost and interquartile range (IQR) for patients with diabetes, $994 (385-1553) mean $1319 (95% CI: 981-1657), was higher than patients with hypertension, $759 (494-1147) mean $914 (95% CI: 825-1003). Female patients aged below 65 years with diabetes had the highest estimated mean costs ($1467 (95% CI: 1177-1828)). Wound care had the highest estimated mean cost of all procedures, $2884 (95% CI: 2004-4149) for patients with diabetes and $2239 (95% CI: 1589-3156) for patients with hypertension. Age below 65 years, medical procedures (amputation, wound care, dialysis, and physiotherapy), the presence of two or more comorbidities, and being prescribed two or more drugs were associated with significantly higher hospitalization costs. Conclusion. Our estimated costs could be used to evaluate and improve current inpatient treatment and management of patients with diabetes and hypertension and determine the most cost-effective interventions to prevent complications and comorbidities.

Diabetes medications: Impact on inflammation and wound healing

Chronic wounds are a common complication in patients with diabetes that often lead to amputation. These non-healing wounds are described as being stuck in a persistent inflammatory state characterized by accumulation of pro-inflammatory macrophages, cytokines and proteases. Some medications approved for management of type 2 diabetes have demonstrated anti-inflammatory properties independent of their marketed insulinotropic effects and thus have underappreciated potential to promote wound healing. In this review, the potential for insulin, metformin, specific sulfonylureas, thiazolidinediones, and dipeptidyl peptidase-4 inhibitors to promote healing is evaluated by reviewing human and animal studies on inflammation and wound healing. The available evidence indicates that diabetic medications have potential to prevent wounds from becoming arrested in the inflammatory stage of healing and to promote wound healing by downregulating pro-inflammatory cytokines, upregulating growth factors, lowering matrix metalloproteinases, stimulating angiogenesis, and increasing epithelization. However, no clinical recommendations currently exist on the potential for specific diabetic medications to impact healing of chronic wounds. Thus, we encourage further research that may guide physicians on providing personalized diabetes treatments that achieve glycemic goals while promoting healing in patients with chronic wounds.

Reconstructive vascular surgery and the extent of tissue damage due to diabetic foot ulcers relates to risk of new ulceration in patients with PAD

OBJECTIVE

There is limited information regarding new ulceration following the healing of ischaemic foot ulcers in diabetic patients. Our aim is to study new ulcerations in the same foot as the previous ulcer(s) in patients with diabetes and severe peripheral artery disease (PAD).

METHOD

Patients with diabetes and severe PAD who healed from previous ulcer(s) (Wagner grade 1-5, at or below the ankle), were recruited for the prospective study from the time of healing of their ulcer. Patients were followed up regarding new ulceration, and their treatments and ulcer status noted either directly or on examination of medical records.

RESULTS

We analysed the data on 602 patients with diabetes and severe PAD with healed foot ulcers, either primarily (n=443, 74%) or after minor amputation (n=159, 26%). Of these 51% (n=305) had revascularisation before healing from the previous ulcer, 34% (n=202) developed a new ulcer on the same foot within 15 months (range 0-106). Amputation was required by 22% (n=45) of patients, with a new ulcer on the same foot. The median survival time of all patients (n=602) was 54 months. By regression analysis, a low maximal Wagner grade for the previous ulcer and reconstructive vascular surgery was related to a decreased risk of developing new ulcers in the same foot.

CONCLUSION

Patients with diabetes and ischaemic foot ulcers have a high-risk for developing new ulcers and amputation in the same foot after healing. The extent of tissue involvement in the previous ulcer and reconstructive vascular surgery affected the risk for development of new ulcers.

Silencing TNFα with lipidoid nanoparticles downregulates both TNFα and MCP-1 in an in vitro co-culture model of diabetic foot ulcers

Diabetes is one of the most formidable diseases facing the world today, with the number of patients growing every year. Poor glycemic control yields a host of complications, such as impaired wound healing. This often results in the formation of diabetic foot ulcers, which carry a poor prognosis because they are notoriously difficult to treat. Current therapies do not address the increased number of infiltrating macrophages to the wound bed that overproduce tumor necrosis factor α (TNFα), which increases fibroblast apoptosis and collagen dismantling and decreases angiogenesis. In this study, we investigated the potential of RNA interference therapy to reduce the inappropriately high levels of TNFα in the wound bed. Although TNFα is a challenging gene silencing target, our lipidoid nanoparticles potently silence TNFα mRNA and protein expression at siRNA doses of 5-100nM without inducing vehicle-related gene silencing or cell death. We also describe the creation of an in vitro macrophage-fibroblast co-culture model, which reflects the TNFα and monocyte chemotactant protein-1 (MCP-1/CCL2) cross-talk that exists in diabetic wounds. Because TNFα induces fibroblasts to produce MCP-1, we show that silencing TNFα results in a downregulation of MCP-1, which should inhibit the recruitment of additional macrophages to the wound. In co-culture experiments, a single lipidoid nanoparticle dose of 100nM siTNFα downregulated TNFα and MCP-1 by 64% and 32%, respectively. These data underscore the potential of lipidoid nanoparticle RNAi treatment to inhibit a positive feedback cycle that fuels the pathogenesis of diabetic foot ulcers.

STATEMENT OF SIGNIFICANCE

Diabetic foot ulcers are a rapidly growing issue worldwide, with current ulcer treatments not as effective as desired. RNA interference therapy represents a largely untapped possible solution to impaired wound healing. We show that siRNA-loaded lipidoid nanoparticles silence the overexpression of tumor necrosis factor α (TNFα) in inflammatory macrophages which leads to a subsequent downregulation of fibroblast-produced macrophage chemotactant protein-1 (MCP-1). Both TNFα and MCP-1 are critical components of the inflammatory feedback loop that exists in chronic wounds. In contrast to the majority of wound drug delivery studies, our study utilizes macrophage/fibroblast co-culture experiments to recapitulate a multicellular wound environment in which cytokine signaling influences inflammation. Results underscore the therapeutic potential of siRNA nanoparticles directed against TNFα in inhibiting two key inflammatory targets in chronic wounds.

Inflammation as a Therapeutic Target for Diabetic Neuropathies

Diabetic neuropathies (DNs) are one of the most prevalent chronic complications of diabetes and a major cause of disability, high mortality, and poor quality of life. Given the complex anatomy of the peripheral nervous system and types of fiber dysfunction, DNs have a wide spectrum of clinical manifestations. The treatment of DNs continues to be challenging, likely due to the complex pathogenesis that involves an array of systemic and cellular imbalances in glucose and lipids metabolism. These lead to the activation of various biochemical pathways, including increased oxidative/nitrosative stress, activation of the polyol and protein kinase C pathways, activation of polyADP ribosylation, and activation of genes involved in neuronal damage, cyclooxygenase-2 activation, endothelial dysfunction, altered Na(+)/K(+)-ATPase pump function, impaired C-peptide-related signaling pathways, endoplasmic reticulum stress, and low-grade inflammation. This review summarizes current evidence regarding the role of low-grade inflammation as a potential therapeutic target for DNs.

Mortality After Nontraumatic Major Amputation Among Patients With Diabetes and Peripheral Vascular Disease: A Systematic Review

High mortality rates have been reported after major amputations of a lower limb secondary to diabetes and peripheral vascular disease. However, the mortality rates have varied across studies. A systematic review of the 5-year mortality after nontraumatic major amputations of the lower extremity was conducted. A data search was performed of Medline using OVID, CINHAL, and Cochrane, 365 abstracts were screened, and 79 full text articles were assessed for eligibility. After review, 31 studies met the inclusion and exclusion criteria. Overall, the 5-year mortality rate was very high among patients with any amputation (major and minor combined), ranging from 53% to 100%, and in patients with major amputations, ranging from 52% to 80%. Mortality after below-the-knee amputation ranged from 40% to 82% and after above-the-knee amputation from 40% to 90%. The risk factors for increased mortality included age, renal disease, proximal amputation, and peripheral vascular disease. Although our previous systematic review of the 5-year mortality after ulceration had much lower rates of death, additional studies are warranted to determine whether amputation hastens death or is a marker for underlying disease severity.

Study of Disease Progression and Relevant Risk Factors in Diabetic Foot Patients Using a Multistate Continuous-Time Markov Chain Model

The diabetic foot is a lifelong disease. The longer patients with diabetes and foot ulcers are observed, the higher the likelihood that they will develop comorbidities that adversely influence ulcer recurrence, amputation and survival (for example peripheral arterial disease, renal failure or ischaemic heart disease). The purpose of our study was to quantify person and limb-related disease progression and the time-dependent influence of any associated factors (present at baseline or appearing during observation) based on which effective prevention and/or treatment strategies could be developed. Using a nine-state continuous-time Markov chain model with time-dependent risk factors, all living patients were divided into eight groups based on their ulceration (previous or current) and previous amputation (none, minor or major) status. State nine is an absorbing state (death). If all transitions are fully observable, this model can be decomposed into eight submodels, which can be analyzed using the methods of survival analysis for competing risks. The dependencies of the risk factors (covariates) were included in the submodels using Cox-like regression. The transition intensities and relative risks for covariates were calculated from long-term data of patients with diabetic foot ulcers collected in a single specialized center in North-Rhine Westphalia (Germany). The detected estimates were in line with previously published, but scarce, data. Together with the interesting new results obtained, this indicates that the proposed model may be useful for studying disease progression in larger samples of patients with diabetic foot ulcers.

Foot Complications and Mortality: Results from Translating Research Into Action for Diabetes (TRIAD)

BACKGROUND

We sought to study the impact of foot complications on 10-year mortality independent of other demographic and biological risk factors in a racially and socioeconomically diverse managed-care population with access to high-quality medical care.

METHODS

We studied 6,992 patients with diabetes in Translating Research Into Action for Diabetes (TRIAD), a prospective observational study of diabetes care in managed care. Foot complications were assessed using administrative claims data. The National Death Index was searched for deaths across 10 years of follow-up (2000-2009).

RESULTS

Charcot's neuro-osteoarthropathy and diabetic foot ulcer with debridement were associated with an increased risk of mortality; however, the associations were not significant in fully adjusted models. Lower-extremity amputation (LEA) was associated with an increased risk of mortality in unadjusted (hazard ratio [HR], 3.21; 95% confidence interval [CI], 2.50-4.12) and fully adjusted (HR, 1.84; 95% CI, 1.28-2.63) models. When we examined the associations between LEA and mortality stratified by sex and race, risk was increased in men (HR, 1.96; 95% CI, 1.25-3.07), Hispanic individuals (HR, 5.17; 95% CI, 1.48-18.01), and white individuals (HR, 2.18; 95% CI, 1.37-3.47). In sensitivity analyses, minor LEA tended to increase the risk of mortality (HR, 1.48; 95% CI, 0.92-2.40), and major LEA was associated with a significantly higher risk of death at 10 years (HR, 1.89; 95% CI, 1.18-3.01).

CONCLUSIONS

In this managed-care population with access to high-quality medical care, LEA remained a robust independent predictor of mortality. The association was strongest in men and differed by race.

Outcomes of Chopart Amputation in a Tertiary Referral Diabetic Foot Clinic: Data From a Consecutive Series of 83 Hospitalized Patients

The purpose of the present retrospective study was to evaluate the outcomes (ie, ulcer recurrence, major amputation, death) in diabetic patients undergoing Chopart amputation because of deep infection or gangrene extending to the midfoot. From 2009 to 2011, 83 patients, aged 71.4 ± 9.3 years, underwent a midtarsal amputation and were followed up until December 31, 2012 (mean follow-up 2.8 ± 0.8 years). Of the 83 patients, 26 were female, 61 required insulin, 47 had renal insufficiency, 19 underwent hemodialysis, 65 had hypertension, 34 had a history of cardiac disease, and 4 had a history of stroke. Chopart amputation was performed in 38 patients (45.8%) with gangrene, 31 (37.4%) with abscess, and 14 (16.9%) with osteomyelitis. Urgent surgery was performed in 56 patients (67.5%). Effective revascularization was performed in 64 patients (77.1%) patients. Of the 83 patients, 47 had healed at a mean period of 164.7 (range 11 to 698) days. Ulcer recurrence developed in 15 patients (31.9%). A major amputation was necessary in 23 patients (27.7%), with an annual incidence of 13.0%. None of the included variables on logistic regression analysis was significantly associated with proximal amputation. Of the 83 patients, 38 (45.8%) died, with an annual incidence of 25.8%. On logistic regression analysis, age (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.01 to 1.16), history of stroke (OR 9.94, 95% CI 3.16 to 31.24), and urgent surgery (OR 2.60, 95% CI 1.14 to 5.93) were associated with mortality. Chopart amputation represents the last chance to avoid major amputation for diabetic patients with serious foot complications. Our success rate was great enough to consider Chopart amputation a viable option for limb salvage in this high-risk population.

High probability of healing without amputation of plantar forefoot ulcers in patients with diabetes

Diabetic foot ulcer is an important entity which in many cases is the first serious complication in diabetes. Although a plantar forefoot location is common, there are few studies on larger cohorts and in such studies there is often a combination of various types of ulcer and ulcer locations. The purpose of this study is to discern the outcome of plantar forefoot ulcers and their specific characteristics in a large cohort. All patients (n = 770), presenting with a plantar forefoot ulcer at a multidisciplinary diabetes foot clinic from January 1, 1983 to December 31, 2012 were considered for the study. Seven hundred one patients (median age 67 [22-95]) fulfilled the inclusion criteria and were followed according to a preset protocol until final outcome (healing or death). Severe peripheral vascular disease was present in 26% of the patients and 14% had evidence of deep infection upon arrival at the foot clinic. Fifty-five percent (385/701) of the patients healed without foot surgery, 25% (173/701) healed after major debridement, 9% (60/701) healed after minor or major amputation and 12% (83/701) died unhealed. Median healing time was 17 weeks. An ulcer classified as Wagner grade 1 or 2 at inclusion and independent living were factors associated with a higher healing rate. Seventy-nine percent of 701 patients with diabetes and a plantar forefoot ulcer treated at a multidisciplinary diabetes foot clinic healed without amputation. For one third some form of foot surgery was needed to achieve healing.

Survival of diabetes patients with major amputation is comparable to malignant disease

INTRODUCTION

Almost all studies on diabetic foot syndrome focused on prevention of amputation and did not investigate long-term prognosis and survival of patients as a primary outcome parameter.

METHODS

We did a retrospective cohort study including 314 patients who had diabetic foot syndrome and underwent amputation between December 1995 and January 2001.

RESULTS

A total of 48% of patients received minor amputation (group I), 15% only major amputation (group II) and 36% initially underwent a minor amputation that was followed by a major amputation (group III). Statistically significant differences were observed in comparison of the median survival of group I to group II (51 vs. 40 months; p = 0.016) and of group II to group III (40 vs. 55 months; p = 0.003).

DISCUSSION

The prognosis of patients with major amputation due to diabetic foot syndrome is comparable to patients with malignant diseases. Vascular interventions did not improve the individual prognosis of patients.