Graftskin, a human skin equivalent, is effective in the management of noninfected neuropathic diabetic foot ulcers: a prospective randomized multicenter clinical trial

OBJECTIVE

We assessed in a randomized prospective trial the effectiveness of Graftskin, a living skin equivalent, in treating noninfected nonischemic chronic plantar diabetic foot ulcers.

RESEARCH DESIGN AND METHODS

In 24 centers in the U.S., 208 patients were randomly assigned to ulcer treatment either with Graftskin (112 patients) or saline-moistened gauze (96 patients, control group). Standard state-of-the-art adjunctive therapy, which included extensive surgical debridement and adequate foot off-loading, was provided in both groups. Graftskin was applied at the beginning of the study and weekly thereafter for a maximum of 4 weeks (maximum of five applications) or earlier if complete healing occurred. The major outcome of complete wound healing was assessed by intention to treat at the 12-week follow-up visit.

RESULTS

At the 12-week follow-up visit, 63 (56%) Graftskin-treated patients achieved complete wound healing compared with 36 (38%) in the control group (P = 0.0042). The Kaplan-Meier median time to complete closure was 65 days for Graftskin, significantly lower than the 90 days observed in the control group (P = 0.0026). The odds ratio for complete healing for a Graftskin-treated ulcer compared with a control-treated ulcer was 2.14 (95% CI 1.23-3.74). The rate of adverse reactions was similar between the two groups with the exception of osteomyelitis and lower-limb amputations, both of which were less frequent in the Graftskin group.

CONCLUSIONS

Application of Graftskin for a maximum of 4 weeks results in a higher healing rate when compared with state-of-the-art currently available treatment and is not associated with any significant side effects. Graftskin may be a very useful adjunct for the management of diabetic foot ulcers that are resistant to the currently available standard of care.

Mechanisms involved in the development and healing of diabetic foot ulceration

We examined the role of vascular function and inflammation in the development and failure to heal diabetic foot ulcers (DFUs). We followed 104 diabetic patients for a period of 18.4 ± 10.8 months. At the beginning of the study, we evaluated vascular reactivity and serum inflammatory cytokines and growth factors. DFUs developed in 30 (29%) patients. DFU patients had more severe neuropathy, higher white blood cell count, and lower endothelium-dependent and -independent vasodilation in the macrocirculation. Complete ulcer healing was achieved in 16 (53%) patients, whereas 13 (47%) patients did not heal. There were no differences in the above parameters between the two groups, but patients whose ulcers failed to heal had higher tumor necrosis factor-α, monocyte chemoattractant protein-1, matrix metallopeptidase 9 (MMP-9), and fibroblast growth factor 2 serum levels when compared with those who healed. Skin biopsy analysis showed that compared with control subjects, diabetic patients had increased immune cell infiltration, expression of MMP-9, and protein tyrosine phosphatase-1B (PTP1B), which negatively regulates the signaling of insulin, leptin, and growth factors. We conclude that increased inflammation, expression of MMP-9, PTP1B, and aberrant growth factor levels are the main factors associated with failure to heal DFUs. Targeting these factors may prove helpful in the management of DFUs.

NETosis Delays Diabetic Wound Healing in Mice and Humans

Upon activation, neutrophils undergo histone citrullination by protein arginine deiminase (PAD)4, exocytosis of chromatin and enzymes as neutrophil extracellular traps (NETs), and death. In diabetes, neutrophils are primed to release NETs and die by NETosis. Although this process is a defense against infection, NETosis can damage tissue. Therefore, we examined the effect of NETosis on the healing of diabetic foot ulcers (DFUs). Using proteomics, we found that NET components were enriched in nonhealing human DFUs. In an independent validation cohort, a high concentration of neutrophil elastase in the wound was associated with infection and a subsequent worsening of the ulcer. NET components (elastase, histones, neutrophil gelatinase-associated lipocalin, and proteinase-3) were elevated in the blood of patients with DFUs. Circulating elastase and proteinase-3 were associated with infection, and serum elastase predicted delayed healing. Neutrophils isolated from the blood of DFU patients showed an increased spontaneous NETosis but an impaired inducible NETosis. In mice, skin PAD4 activity was increased by diabetes, and FACS detection of histone citrullination, together with intravital microscopy, showed that NETosis occurred in the bed of excisional wounds. PAD4 inhibition by Cl-amidine reduced NETting neutrophils and rescued wound healing in diabetic mice. Cumulatively, these data suggest that NETosis delays DFU healing.

Transforming growth factor-beta 1, 2, 3 and receptor type I and II in diabetic foot ulcers

AIMS

To study the distribution of transforming growth factor-beta (TGF-beta) 1, 2 and 3, and TGF-beta receptor types I and II in diabetic foot ulcers, diabetic skin and normal skin by immunohistochemistry, immunofluorescence and Western blotting. We also compared the TGF-betas with those of chronic venous ulcers.

METHODS

Skin biopsies were obtained from the leg or the foot of non-diabetic and diabetic subjects, and from the edge of diabetic foot ulcers and chronic venous ulcers. Distribution (by immunofluorescence and immunocytochemistry) of TGF-beta 1, 2 and 3 and TGF-beta receptors (RI and RII) was done by staining 8-microm skin sections using appropriate antibodies. Protein levels of TGF-beta were measured by Western blot analysis.

RESULTS

TGF-beta3 expression was increased in the epithelium at the edge of diabetic foot ulcers, being more intense than diabetic and normal skin (P = 0.03, 0.02, respectively), as was its expression in venous ulcers compared with normal skin. However, TGF-beta1 expression was not increased in diabetic foot ulcers and chronic venous ulcers, and was comparable to diabetic and normal skin. There was also no increase for the receptors in diabetic foot ulcers.

CONCLUSION

The lack of TGF-beta1 up-regulation in both diabetic foot ulcers and venous ulcers may explain the impaired healing in these chronic wounds, and could represent a general pattern for chronicity.

Synergistic interaction between Astragali Radix and Rehmanniae Radix in a Chinese herbal formula to promote diabetic wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali Radix (AR) and Rehmanniae Radix (RR) are two traditional Chinese medicines widely used in China for treating diabetes mellitus and its complications, such as diabetic foot ulcer.

AIM OF STUDY

In our previous study, a herbal formula NF3 comprising AR and RR in the ratio of 2:1 was found effective in enhancing diabetic wound healing in rats through the actions of tissue regeneration, angiogenesis promotion and inflammation inhibition. The aims of the present study were to investigate the herb-herb interaction (or the possible synergistic effect) between AR and RR in NF3 to promote diabetic wound healing and to identify the principal herb in the formula by evaluating the potencies of individual AR and RR in different mechanistic studies.

MATERIALS AND METHODS

A chemically induced diabetic foot ulcer rat model was used to examine the wound healing effect of NF3 and its individual herbs AR and RR. For mechanistic studies, murine macrophage cell (RAW 264.7) inflammation, human fibroblast (Hs27) proliferation and human endothelial cell (HMEC-1) migration assays were adopted to investigate the anti-inflammatory, granulation formation and angiogenesis-promoting activities of the herbal extracts, respectively.

RESULTS

In the foot ulcer animal model, neither AR nor RR at clinical relevant dose (0.98g/kg) promoted diabetic wound healing. However, when they were used in combination as NF3, synergistic interaction was demonstrated, of which NF3 could significantly reduce the wound area of rats when compared to water group (p<0.01). For anti-inflammation and granulation formation, AR was more effective than RR in inhibiting lipopolysaccharide (LPS)-induced nitric oxide production from RAW 264.7 cells and promoting Hs27 fibroblast proliferation. In the aspect of angiogenesis promotion, only NF3 promoted cell migration of HMEC-1 cells.

CONCLUSIONS

AR plays a preeminent role in the anti-inflammatory and fibroblast-proliferating activities of NF3. The inclusion of RR, however, is crucial for NF3 to exert its overall wound-healing as well as the underlying angiogenesis-promoting effects. The results of present study justified the combined usage of AR and RR in the ratio of 2:1 as NF3 to treat diabetic foot ulcer and illustrated that AR is the principal herb in this herbal formula.

Wound bioburden and infection-related complications in diabetic foot ulcers

The identification and diagnosis of diabetic foot ulcer (DFU) infections remains a complex problem. Because inflammatory responses to microbial invasion may be diminished in persons with diabetes, clinical signs of infection are often absent in persons with DFUs when infection is limited to localized tissue. In the absence of these clinical signs, microbial load is believed to be the best indicator of infection. Some researchers, however, believe microbial load to be insignificant and type of organism growing in the ulcer to be most important. Previous studies on the microbiology of DFUs have not provided enough evidence to determine the microbiological parameters of importance.Infection-related complications of DFUs include wound deterioration, osteomyelitis, and amputation. Risk factors for amputation include age, peripheral vascular disease, low transcutaneous oxygen, smoking, and poor glycemic control. These risk factors are best measured directly with physiological measures of arterial perfusion, glycemic control, sensory neuropathy, plantar pressures, and activity level and by controlling off-loading. DFU bioburden has not been examined as a risk factor for infection-related complications. To address the relationship between wound bioburden and the development of infection-related complications in DFUs, tightly controlled prospective studies based on clearly defined, valid measures of wound bioburden and wound outcomes are needed. This article reviews the literature and proposes a model of hypothesized relationships between wound bioburden-including microbial load, microbial diversity, and pathogenicity of organisms-and the development of infection-related complications.

Immune aging in diabetes and its implications in wound healing

Immune systems have evolved to recognize and eliminate pathogens and damaged cells. In humans, it is estimated to recognize 109 epitopes and natural selection ensures that clonally expanded cells replace unstimulated cells and overall immune cell numbers remain stationary. But, with age, it faces continuous repertoire restriction and concomitant accumulation of primed cells. Changes shaping the aging immune system have bitter consequences because, as inflammatory responses gain intensity and duration, tissue-damaging immunity and inflammatory disease arise. During inflammation, the glycolytic flux cannot cope with increasing ATP demands, limiting the immune response's extent. In diabetes, higher glucose availability stretches the glycolytic limit, dysregulating proteostasis and increasing T-cell expansion. Long-term hyperglycemia exerts an accumulating effect, leading to higher inflammatory cytokine levels and increased cytotoxic mediator secretion upon infection, a phenomenon known as diabetic chronic inflammation. Here we review the etiology of diabetic chronic inflammation and its consequences on wound healing.

Long Noncoding RNA GAS5 Regulates Macrophage Polarization and Diabetic Wound Healing

A central feature of diabetic (Db) wounds is the persistence of chronic inflammation, which is partly due to the prolonged presence of proinflammatory (M1) macrophages. Using in vivo and in vitro analyses, we have tested the hypothesis that long noncoding RNA GAS5 is dysregulated in Db wounds. We have assessed the contribution of GAS5 to the M1 macrophage phenotype, as well as the functional consequences of knocking down its expression. We found that expression of GAS5 is increased significantly in Db wounds and in cells isolated from Db wounds. Hyperglycemia induced GAS5 expression in macrophages in vitro. Overexpression of GAS5 in vitro promoted macrophage polarization toward an M1 phenotype by upregulating signal transducer and activator of transcription 1. Of most significance in our judgment, GAS5 loss-of-function enhanced Db wound healing. These data indicate that the relative level of long noncoding RNA GAS5 in wounds plays a key role in the wound healing response. Reductions in the levels of GAS5 in wounds appeared to enhance healing by promoting transition of M1 macrophages to M2 macrophages. Thus, our results suggest that targeting long noncoding RNA GAS5 may provide a therapeutic intervention for correcting impaired Db wound healing.

Both autologous bone marrow mononuclear cell and peripheral blood progenitor cell therapies similarly improve ischaemia in patients with diabetic foot in comparison with control treatment

BACKGROUND

The aim of our study was to compare the effect of bone marrow mononuclear cell and peripheral blood progenitor cell therapies in patients with diabetic foot disease and critical limb ischaemia unresponsive to revascularization with conservative therapy.

METHODS

Twenty-eight patients with diabetic foot disease (17 treated by bone marrow cells and 11 by peripheral blood cell) were included into an active group and 22 patients into a control group without cell treatment. Transcutaneous oxygen pressure and rate of major amputation, as the main outcome measures, were compared between bone marrow cells, peripheral blood cell and control groups over 6 months; both cell therapy methods were also compared by the characteristics of cell suspensions. Possible adverse events were evaluated by changes of serum levels of angiogenic cytokines and retinal fundoscopic examination.

RESULTS

The transcutaneous oxygen pressure increased significantly (p < 0.05) compared with baseline in both active groups after 6 months, with no significant differences between bone marrow cells and peripheral blood cell groups; however, no change of transcutaneous oxygen pressure in the control group was observed. The rate of major amputation by 6 months was significantly lower in the active cell therapy group compared with that in the control group (11.1% vs. 50%, p = 0.0032), with no difference between bone marrow cells and peripheral blood cell. A number of injected CD34+ cells and serum levels of angiogenic cytokines after treatment did not significantly differ between bone marrow cells and peripheral blood cell.

CONCLUSIONS

Our study showed a superior benefit of bone marrow cells and peripheral blood cell treatments of critical limb ischaemia in patients with diabetic foot disease when compared with conservative therapy. There was no difference between both cell therapy groups, and no patient demonstrated signs of systemic vasculogenesis.

25-Hydroxyvitamin D [25(OH)D] levels and diabetic foot ulcer: is there any relationship?

AIMS

In recent years, there has been an effort to understand possible roles of 25(OH)D, including its role in the immune system particularly on T cell medicated immunity, pancreatic insulin secretion and insulin action. 25(OH)D stimulates the cell differentiation and reduces cell proliferation, which is essential for cell growth and wound healing. However, data on the association between low level of plasma 25(OH)D and diabetic foot syndrome are scarce.

MATERIALS AND METHODS

Circulating plasma levels of 25(OH)D were measured in diabetic patients with ulcer (n=162) and without ulcer (n=162) in a prospective cohort hospital based study.

RESULTS

Of these patients, 85.1% had type 2 diabetes. Subjects with diabetic foot ulcer showed lower median plasma level of 25(OH)D [6.3(4.2-11.1) vs 28.0(21.4-37.0)] ng/ml after adjusting the age and BMI. Regardless of the low levels of 25(OH)D in cases and controls, it was associated with neuropathy, sex (female), duration of ulcer healing, and smoking status and independent of confounding factors, including BMI (kg/m²), A1c (%), hypertension, nephropathy, foot ulcer, retinopathy, CAD, PAD, HDL-C (mg/dl) and LDL-C (mg/dl). The factors which predict the risk of developing ulcer independent of 25(OH)D status were A1c (>6.9%) [OR 4.37; RR 1.77], HDL-C (<40mg/dl) [OR 1.16; RR 1.07], LDL-C (>100mg/dl) [OR 1.07; RR 1.03], triglycerides (>200mg/dl) [OR 1.40; RR 1.19], neuropathy [OR 6.88; RR 3.12], retinopathy [OR 3.34; RR 1.91], hypertension [OR 1.64; RR 1.28], nephropathy [OR 3.12; RR 1.87] and smoking [OR 4.53; RR 2.99] using odds and risk ratios.

CONCLUSION

It is not clear whether the suppression of delayed wound healing seen during 25(OH)D deficiency is due to the secondary effect or is a direct action of vitamin D on certain components of the immune system. Long-term randomized trials are needed to see the impact of vitamin D supplementation on the outcome of diabetic foot patients.

The diagnosis of osteomyelitis of the foot in diabetes: microbiological examination vs. magnetic resonance imaging and labelled leucocyte scanning

AIMS

Foot infections and their sequelae are among the most common and severe complications of diabetes mellitus. As diabetic patients with foot infections develop osteomyelitis and may progress to amputation, early diagnosis of osteomyelitis is critical.

METHODS

We compared the diagnostic values of labelled leucocyte scanning with Tc(99)m, magnetic resonance imaging (MRI) and microbiological examination of bone tissue specimens with histopathology, the definitive diagnostic procedure. Thirty-one diabetic patients with foot lesions were enrolled in the study and histopathological examination was performed in all. Patients had clinically suspected foot lesions of > or = grade 3 according to the classification of Wagner.

RESULTS

Bone specimens were obtained for histopathological examination. Microbiology had a sensitivity of 92% and specificity of 60%. Labelled leucocyte scanning had a sensitivity of 91%, specificity of 67%, and MRI a sensitivity of 78%, specificity of 60%.

CONCLUSIONS

Microbiological examination may be as useful as and less costly than other diagnostic procedures and is the only method which can guide the choice of antibiotic therapy.

Adiponectin, resistin and IL-6 plasma levels in subjects with diabetic foot and possible correlations with clinical variables and cardiovascular co-morbidity

INTRODUCTION

It is very suggestive that diabetic foot is characterized by a pronounced inflammatory reaction and the pathogenic significance of this inflammation has received little attention. On this basis the aim of our study was to evaluate plasma levels of adiponectin, resistin and IL-6 in subjects with diabetic foot in comparison with subjects without foot complications.

MATERIALS AND METHODS

We recruited 34 subjects with type 2 diabetes mellitus and foot ulceration hospitalized for every condition related to diabetic disease, but not for new vascular events (group A). As controls we recruited 37 patients with type 2 diabetes mellitus without foot ulceration (group B) hospitalized for every condition related to diabetic disease, but not for new vascular events. Adiponectin, Resistin and IL-6 serum levels were evaluated.

RESULTS

Subjects of group A showed lower median plasma levels of adiponectin [7.7450 (4.47-12.17) μg/ml vs 8.480 (5.15-12.87) μg/ml], higher median plasma levels of IL-6 [3.21 (1.23-5.34) pg/ml vs 2.73 (1.24-3.97 pg/ml)] and of resistin [3.860 (2.96-6.29 ng/ml) vs 3.690 (2.,37-6.5 ng/ml)].

CONCLUSION

Our study demonstrated that diabetic subjects with diabetic foot showed in comparison with diabetics without diabetic foot higher IL-6 and resistin plasma levels, lower adiponectin plasma levels.

Coming events cast their shadows before: detecting inflammation in the acute diabetic foot and the foot in remission

The incidence of diabetic foot complications, most notably wounds, is increasing worldwide. Most people who present for care of a foot wound will become infected. Globally, this results in one major amputation every 30 seconds with over 2500 limbs lost per day. Presently, clinicians assess circulation, neuropathy and plantar pressures to identify the risk of foot ulceration. Several studies have suggested prevention of foot ulcers by identifying individuals at high risk and treating for lower extremity complications. Our group has proposed several diagnostics as well as prevention strategies, especially thermography and thermometry for management of patients with diabetic foot complications. These strategies employ non-invasive assessment of inflammation for acute as well as chronic care for the foot, with the intent to prevent ulceration/re-ulceration and subsequent traumatic amputations. The authors' review some important clinical studies and ongoing research in this area, with the long-term goal to further the role of thermography and thermometry in clinical care for the diabetic foot.

Increased expression of TLR9 associated with pro-inflammatory S100A8 and IL-8 in diabetic wounds could lead to unresolved inflammation in type 2 diabetes mellitus (T2DM) cases with impaired wound healing

BACKGROUND

Type 2 diabetes mellitus (T2DM) is characterized by persistent hyperglycemia which causes a chain of abrupt biochemical and physiological changes. Immune dys-regulation is the hallmark of T2DM that could contribute to prolonged inflammation causing transformation of wounds into non-healing chronic ulcers. Toll like receptor -9 (TLR9) is a major receptor involved in innate immune regulation. TLR9 activation induces release of pro-inflammatory molecules like S100A8 and interleukin-8 (IL-8) by myeloid cells causing migration of myeloid cells to the site of inflammation. We hypothesized that pro-inflammatory S100A8 and IL-8 proteins could cause persistent inflammation in chronic wounds like diabetic foot ulcer (DFU) and may contribute to impaired wound healing in T2DM patients.

MATERIALS AND METHODS

Expression of TLR9 and its downstream effector molecules S100A8, and IL-8 were analyzed in chronic diabetic wound and non-diabetic control wound tissue samples by semiquantitative reverse transcriptase - polymerase chain reaction (RT-PCR), quantitative RT-PCR, western blot and immunofluorescence. CD11b(+)CD33(+) myeloid cells were analyzed by flow cytometry.

RESULTS

TLR9 message and protein were higher in diabetic wounds compared to control wounds (p=0.03, t=2.21 for TLR9 mRNA; p=<0.001, t=4.21 for TLR9 protein). TLR9 down-stream effector molecules S100A8 and IL-8 were also increased in diabetic wounds (p=0.003, t=3.1 for S100A8 mRNA; p=0.04, t=2.04 for IL-8). CD11b(+) CD33(+) myeloid cells were decreased in T2DM as compared to non-diabetic controls (p=0.001, t=3.6). DFU subjects had higher levels of CD11b(+) CD33(+) myeloid cells as compared to non-DFU T2DM control (p=0.003, t=2.8). Infection in the wound microenvironment could be the cause of increase in CD11b(+)CD33(+) myeloid cells in DFU (p=0.03, t=2.5).

CONCLUSION

The up-regulation of myeloid cell-derived pro-inflammatory molecules S100A8 and IL-8 in combination with lower levels of CD11b(+) CD33(+) myeloid cells may cause the impairment of wound healing in T2DM subjects leading to chronic ulcers.

Low recruitment of immune cells with increased expression of endothelial adhesion molecules in margins of the chronic diabetic foot ulcers

Diabetic foot skin close to an ulcer shows only a few infiltrating cells compared to nondiabetic inflamed tissues. Diabetes is characterized by thickened basement membrane of the blood arterioles and capillaries. This may affect the transcapillary transport of immune humoral factors and cells to the extravascular space. We analyzed by immunohistochemistry the phenotype and expression pattern of adhesion molecules on leukocyte, dermal fibroblast, and endothelial cells in diabetic foot ulcers. Although there was accumulation of granulocytes on the surface and superficial layers of the granulation tissue, rare perivascular granulocyte infiltrates in the dermis were seen. Moreover, lack of macrophage and CD3+ T cell infiltrates was observed. In contrast, there was increased intensity of CD1a staining of Langerhans cells in the epidermis and papillary dermis (p < 0.05). Fibroblasts revealed increased presence in the ulcer margins compared with normal skin (p < 0.05). Skin endothelial cells expressed stronger von Willebrand factor and E-selectin compared with normal skin (p < 0.05). Our study provides evidence that increased expression of endothelial cell adhesion molecules responsible for immunocyte extravasation is not associated with increased inflammatory cell infiltration of the ulcerated diabetic foot tissue. We suggest that the healing process of diabetic foot ulcers may be hampered by mechanisms decreasing accumulation of leukocytes. This implies that pharmacological or biological stimulation of leukocyte extravasation into the ulcer tissue should be tried.

Assessing diabetic foot osteomyelitis remission with white blood cell SPECT/CT imaging

AIMS

Diabetic foot osteomyelitis is an important risk factor of lower limb amputation. Antibiotic therapy is often effective in preventing surgery. However, the duration of antibiotic therapy is difficult to define in the absence of a marker to diagnose osteomyelitis remission at the end of the treatment. In this study, we assessed the diagnostic performance of white blood cell SPECT/CT imaging for evaluating osteomyelitis remission.

PATIENTS AND METHODS

Twenty-nine out of 42 episodes of diabetic foot osteomyelitis seen between December 2009 and April 2012 had radiographs, a three-phase bone scintigraphy and a white blood cell SPECT/CT at the end of antibiotic therapy. They were treated with antibiotics alone and considered in clinical remission. White blood cell SPECT/CT results were considered positive when abnormal uptake in the osteomyelitis location was identified. Osteomyelitis remission was defined by the absence of an osteomyelitis relapse after 12 months' follow-up.

RESULTS

A negative white blood cell SPECT/CT was seen for 22 episodes of osteomyelitis. All of them were in remission. A positive white blood cell SPECT/CT was observed for seven episodes. A relapse occurred in five episodes (71.5%) after a median duration of 4 months (2-7 months). Sensitivity, specificity, positive predictive value and predictive negative value in predicting osteomyelitis relapse after the discontinuation of antibiotic treatment were, respectively, for radiographs 80%, 33%, 20% and 89%; for three-phase bone scintigraphy 100%, 12.5%, 15.5% and 100%; and for the white blood cell SPECT/CT 100%, 91.5%, 71.5% and 100%.

CONCLUSION

Negative uptake on white blood cell SPECT/CT is a good marker for diagnosis of diabetic foot osteomyelitis remission and might be very useful in guiding antibiotic therapy.

miR-203 Acts as an Inhibitor for Epithelial-Mesenchymal Transition Process in Diabetic Foot Ulcers via Targeting Interleukin-8

OBJECTIVES

As a complication of diabetes mellitus (DM), one of the leading causes for death and disability for DM patients is diabetic foot ulcers (DFUs). Epithelial to mesenchymal transition (EMT) plays a critical role in wound healing of DFUs. miR-203 is specifically enriched in keratinocytes and has been shown to target interleukin 8 (IL-8), which acts as an activator for the EMT process. In this study, we explored the interaction between miR-203 and IL-8 in DFU rat models and human keratinocyte cells, underlying the mechanism of miR-203's function in DFUs progression.

METHODS

DFU rat models were used to test gene expression in DFU progression. Diabetic keratinocyte cell lines were used to validate in vitro. Wound healing and Transwell assays were applied to evaluate cell migration and invasion abilities. The EMT process was estimated by testing expression of E-cadherin, Vimentin and Slug. The interaction between miR-203 and IL-8 was determined by Luciferase assay.

RESULTS

Our results demonstrated that the wound-healing process had been slowed in DFUs, and the advanced glycation end products (AGEs) and the receptor for advanced glycation end products (RAGEs) in wound tissue were of a higher expression than those in normal rat. miR-203 was increased in skin tissues from DFU rat models, while IL-8 was decreased. Through knock-down of miR-203 in AGE-treated keratinocyte cells, it had been shown that the downregulation of miR-203 could promote cell proliferation and migration, and facilitate the EMT process. Meanwhile, Luciferase assay proved that miR-203 could directly target and inhibit IL-8. The repression of IL-8 could rescue the outcomes brought about by miR-203 inhibition.

CONCLUSIONS

The upregulation of miR-203 in DFU tissues impaired wound healing by the repress EMT process. Specific knock-down of miR-203 could promote wound healing through the reactivation of its target gene IL-8 and the downstream IL-8/AKT pathway.

Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ratio are Associated with Lower Extremity Vascular Lesions in Chinese Patients with Type 2 Diabetes

BACKGROUND

Neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are inflammatory markers used for prediction of chronic complications of diabetes. Lower extremity arterial disease (LEAD) is one of chronic complications of type 2 diabetes mellitus (T2DM). The correlation between NLR, PLR, and lower extremity vascular lesions was investigated in subjects with T2DM to determine the best predictive marker for LEAD.

METHODS

Three hundred thirty-five patients with T2DM (199 males and 136 females; age 54.12 ± 14.07 years) were enrolled. Blood differential counts and anklebrachial index (ABI) were assessed. Patients were divided into the LEAD group (ABI ≤ 0.9, n = 236) and non-LEAD group (ABI > 0.9, n = 99), and NLR and PLR were compared between the two groups. The independent risk factors for LEAD were analyzed using a logistic regression model. Receiver operating characteristic (ROC) curve analysis was used to assess the optimal cutoff values of PLR and NLR for prediction of LEAD.

RESULTS

NLR and PLR in the LEAD group were significantly increased compared to non-LEAD group patients. Univariate analyses identified that NLR was positively correlated with age, glycosylated hemoglobin (HbA1c), triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and 2-hours postprandial glucose levels. PLR was positively correlated with age, duration of T2DM, HbA1c, TG, TC, and LDL, but negatively correlated with diastolic blood pressure and fasting C-peptide levels. Binary logistic regression analysis identified that age, total number of white blood cells, PLR, and TC were significant and independent factors of diabetic LEAD. Moreover, ROC curve analysis showed that NLR and PLR were both predictive markers of LEAD in diabetes, and that the area under the PLR curve was larger than NLR.

CONCLUSIONS

NLR and PLR are positively correlated with LEAD in diabetes. PLR was superior to NLR as a predictor of LEAD in diabetes.

Phagocytic activity of neutrophils improves over the course of therapy of diabetic foot infections

AIMS

The aim of this study was to investigate changes in phagocytic activity of neutrophils of type 2 diabetic patients with foot infections over short treatment courses. The potential utility of the phagocytic index in determining the efficacy of treatment modalities and it's relationship with metabolic control parameters were evaluated.

METHODS

The phagocytic activity of neutrophils was determined in blood samples of 38 type 2 diabetic patients with foot infections (14 women and 24 men). Mean age and mean duration of diabetes were 66.3+/-9.4 and 19.1+/-11.2 (yrs), respectively. All patients received standard treatment (intensive insulin therapy, antibiotherapy, hyperbaric oxygen therapy and surgical debridement). Phagocytic activity of neutrophils was determined by a standard method. Phagocytic activity of neutrophils, acute phase proteins (C-reactive protein) and glycosylated haemoglobin was determined before therapy and two weeks later.

RESULTS

The phagocytic index before and after therapy were 47.7+/-11.4 and 62.5+/-15.6, respectively (p<0.05). There was a significant correlation between phagocytic index and both CRP and HbA1c (r=0.52, p<0.05 and r=-0.41, p<0.05, respectively).

CONCLUSIONS

Derangement of carbohydrate metabolism may underlie the impairment of bactericidal activity of neutrophils of poorly controlled diabetic patients. These data reveal that phagocytic activity improves during short-course standard therapy and might enable monitoring of efficacy of treatment modalities in diabetic patients with foot infections.

Genetic and epigenetic alterations in Toll like receptor 2 and wound healing impairment in type 2 diabetes patients

AIM

Persistent hyperglycemic microenvironment in type 2 diabetes mellitus (T2DM) leads to the development of secondary complications like wound healing impairment. Proper co-ordination of innate immune system plays an integral role in wound healing. Toll like receptors (TLRs) are prominent contributors for the induction of the innate immune and inflammation response. TLR2 is an important extracellular member in mammalian TLR family and has been shown to be a potent player in the wound healing mechanism.

METHODS

Expressional status of TLR2 was seen in wounds of T2DM cases with respect to the severity of wounds in 110 human lower extremity wounds. The methylation status of TLR2 promoter was also examined.

RESULTS

Although TLR2 transcripts were downregulated in T2DM wounds compared to control, their levels tend to increase with the severity of T2DM wounds. The methylation status of TLR2 gene promoter was not significantly different among different grades of wounds in T2DM subjects. The CpG sites investigated were totally or partially methylated in majority of DFU cases.

CONCLUSION

TLR2 down regulation in wounds of T2DM patients compared to non diabetic patients may lead to development of non healing chronic ulcers in them.

Relationship between systemic immune inflammation index and amputation in patients with diabetic foot ulcer

AIM

The systemic immune inflammation index (SII) is a cost-effective biomarker calculated by lymphocyte, neutrophil and platelet counts and is currently being studied in various diseases. Since there is no study examining the relationship between SII and diabetic foot ulcers (DFU) in the literature, our aim was to investigate the relationship between SII and amputation rate in DFU.

METHODS

Type 2 DM 511 patients with DFU were screened from 2017 to 2021. Laboratory data obtained on the first day of hospitalization were considered. Platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR) and SII were calculated from routine blood count. Participants were divided into two groups as amputation (Group 1) and non-amputation (Group 2).

RESULTS

Amputation rate was 18.8%. The A1c (8.80 (3.26) % vs. 9.52 (3.10) %, p = 0.007) and HGB (10.17 ± 2.16 g/dL vs. 12.05 ± 2.20 g/dL, p < 0.001) levels, and lymphocyte count (1.81 (1.16) vs. 2.05 (1.11), p = 0.015) were significantly lower in Group 1 than Group 2. The counts of WBC (14.01 (9.16) × 109/L vs. 10.41 (5.82) × 109/L), PLT (393.35 (196.98) × 109/L vs. 312.05 (141.33) × 109/L), neutrophil (11.52 (8.75) × 109/L vs. 6.93 (5.96) × 109/L), PLR (226.04 (159.24) × 109/L vs. 153.12 (101.91) × 109/L), NLR (6.64 (6.93) vs. 3.34 (3.99)) and SII (2505.86 (3957.47) × 109/L vs. 1092.50 (1476.08) × 109/L), and the levels of CRP (14.12 (12.66) mg/dL vs. 3.86 (12.63) mg/dL) and ESR (87.50 (50.50) mm/h vs. 63.00 (57.25) mm/h) were significantly higher in Group 1 than Group 2 (all p < 0.001). AUC of ROC analysis of PLR was 0.666 (95% CI, 0.604-0.728), NLR was 0.695 (95% CI, 0.638-0.752) and SII was 0.716 (95% CI, 0.661-0.772) for the predicting of amputation and the SII had the best AUC with 67.4% sensitivity and 63.3%specificty.

CONCLUSION

SII is a cost-effective and readily available marker, but alone may not be sufficient to predict the risk of amputation in DFU. In our results, the predictive role of SII alone or with other markers for future DFU and its role in predicting other chronic diabetic complications will be evaluated in extensive studies.

Plasma thrombin-activatable fibrinolysis inhibitor (TAFI) antigen levels in diabetic foot ulcers

Plasma TAFI may participate in arterial thrombosis in cardiovascular diseases (CVD) and may be involved in the mechanism of vascular endothelial damage in diabetic patients. The aim of this study was to investigate the association of plasma TAFI antigen level in the development of diabetic foot ulcer in Type 2 diabetes. The TAFI antigen levels were determined in 50 patients with diabetic foot ulcers and 34 patients without diabetic foot ulcers and 25 healthy individuals. We measured TAFIa/ai antigen in plasma samples with a commercially available ELISA Kit. Diabetic foot ulcer group and diabetic group were similar in terms of mean age and sex distribution. Diabetes duration, retinopathy, neuropathy, macrovascular disease and infection were related to diabetic foot ulcers. HbA1c, HDL-cholesterol and Folic Acid levels were decreased in the diabetic foot ulcer group. TAFI levels were 99.44 ± 55.94% in control group, 135.21 ± 61.05% in diabetic foot ulcer group, 136.75 ± 59.38% in diabetic group and was statistically different (P < 0.05). But no difference was seen in TAFI levels between the diabetic foot ulcer group and diabetic group (P > 0.05). No significant difference in plasma TAFI levels were seen between diabetic foot ulcer stages. TAFI antigen levels are increased in Type 2 diabetic patients, but are not related to diabetic foot ulcer development.

Serum prolidase activity in diabetic foot ulcers

Impaired wound healing is an important problem in diabetes mellitus; however, its pathogenesis remains unclear. We aimed to evaluate serum prolidase activity (SPA), an important marker of collagen turnover, in subjects with and without diabetic foot ulcers as compared with healthy controls. Twenty-seven patients with diabetic foot ulcers (foot ulcer group), 27 patients without diabetic foot ulcers (diabetic control group) and 27 healthy controls were enrolled. The study groups had similar age, sex distribution and body mass index. Metabolic and inflammatory parameters as well as SPA were determined. The diabetic foot ulcer group had significantly higher SPA (both p < 0.001) when compared with the diabetic and the healthy control groups. SPA showed a positive correlation with high-sensitive C-reactive protein and a negative correlation with high-density lipoprotein cholesterol levels (r = 0.313, p = 0.021 and r = -0.233, p = 0.036, respectively). No correlation was detected between SPA and glycaemic parameters. SPA appears to be higher in patients with diabetic foot ulcers when compared with patients without diabetic foot ulcers and healthy controls. The underlying mechanisms of elevated SPA and its clinical significance in predicting the natural course of wound healing in diabetic foot ulcers needs to be further evaluation.

An Alteration of Lymphocytes Subpopulations and Immunoglobulins Levels in Patients with Diabetic Foot Ulcers Infected Particularly by Resistant Pathogens

The aim of our study was to analyse immune abnormalities in patients with chronic infected diabetic foot ulcers (DFUs) especially those infected by resistant microorganisms. Methods. 68 patients treated in our foot clinic for infected chronic DFUs with 34 matched diabetic controls were studied. Patients with infected DFUs were subdivided into two subgroups according to the antibiotic sensitivity of causal pathogen: subgroup S infected by sensitive (n = 50) and subgroup R by resistant pathogens (n = 18). Selected immunological markers were compared between the study groups and subgroups. Results. Patients with infected chronic DFUs had, in comparison with diabetic controls, significantly reduced percentages (p < 0.01) and total numbers of lymphocytes (p < 0.001) involving B lymphocytes (p < 0.01), CD4+ (p < 0.01), and CD8+ T cells (p < 0.01) and their naive and memory effector cells. Higher levels of IgG (p < 0.05) including IgG1 (p < 0.001) and IgG3 (p < 0.05) were found in patients with DFUs compared to diabetic controls. Serum levels of immunoglobulin subclasses IgG2 and IgG3 correlated negatively with metabolic control (p < 0.05). A trend towards an increased frequency of IgG2 deficiency was found in patients with DFUs compared to diabetic controls (22% versus 15%; NS). Subgroup R revealed lower levels of immunoglobulins, especially of IgG4 (p < 0.01) in contrast to patients infected by sensitive bacteria. The innate immunity did not differ significantly between the study groups. Conclusion. Our study showed changes mainly in the adaptive immune system represented by low levels of lymphocyte subpopulations and their memory effector cells, and also changes in humoral immunity in patients with DFUs, even those infected by resistant pathogens, in comparison with diabetic controls.