Nicholas Tentolouris

FORT and FORD: two simple and rapid assays in the evaluation of oxidative stress in patients with type 2 diabetes mellitus.

The aim of the study was to evaluate the levels of free oxygen radicals and free oxygen radicals defense in patients with newly diagnosed type 2 diabetes mellitus (T2DM). The disease seems to be involved strongly in the production of reactive oxygen species. Forty-five patients with newly diagnosed T2DM and 20 apparently healthy individuals (control group) were included in the study. Reactive oxygen species were determined using the free oxygen radicals (FORT) test, which is based on the Fenton reaction. In this method, the hydroperoxides reacted with the transition metal ions liberated from the proteins and were converted to alkoxy and peroxy radicals. The radical species produced by the reaction, which are directly proportional to the quantity of lipid peroxides, interact with an additive that forms a radical molecule. Similarly, the free oxygen radicals defense (FORD) test uses preformed stable and colored radicals and determines the decrease in absorbance that is proportional to the blood antioxidant concentration. We found that (a) FORT levels were increased in diabetic patients (2.86 +/- 0.56 mmol/L H(2)O(2)) compared with controls (1.87 +/- 0.26 mmol/L H(2)O(2)) (P < .0001) and (b) FORD levels were lower in diabetic patients (1.23 +/- 0.18 mmol/L Trolox) compared with controls (1.34 +/- 0.14 mmol/L Trolox) (P < .01). The intraassay and interassay coefficients of variation were 3.7% and 6.2%, respectively, for FORT and 4.2% and 6.6%, respectively, for FORD. Determination of free oxygen radicals and free oxygen radicals defense seems to play an important role in the generation and evaluation of oxidative stress, an imbalance between oxidants and antioxidants that can lead to oxidative damage and is involved in the pathogenesis of several diseases, such as T2DM.

Evaluation of three methods for retrospective correction of vignetting on medical microscopy images utilizing two open source software tools.

Correction of vignetting on images obtained by a digital camera mounted on a microscope is essential before applying image analysis. The aim of this study is to evaluate three methods for retrospective correction of vignetting on medical microscopy images and compare them with a prospective correction method. One digital image from four different tissues was used and a vignetting effect was applied on each of these images. The resulted vignetted image was replicated four times and in each replica a different method for vignetting correction was applied with fiji and gimp software tools. The highest peak signal‐to‐noise ratio from the comparison of each method to the original image was obtained from the prospective method in all tissues. The morphological filtering method provided the highest peak signal‐to‐noise ratio value amongst the retrospective methods. The prospective method is suggested as the method of choice for correction of vignetting and if it is not applicable, then the morphological filtering may be suggested as the retrospective alternative method.

Subclinical atherosclerosis in Systemic Lupus Erythematosus: Comparable risk with Diabetes Mellitus and Rheumatoid Arthritis☆

OBJECTIVE Although a high risk of subclinical atherosclerosis has been reported in Systemic Lupus Erythematosus (SLE), it is not adequately compared with that observed in other rheumatic and non-rheumatic high-cardiovascular (CVD) risk diseases, such as Rheumatoid Arthritis (RA) and Diabetes Mellitus (DM). Our objective was to evaluate the relative risk (RR) of subclinical atherosclerosis in SLE, RA and DM patients compared to healthy controls, and examine potential associations with traditional and disease-related CVD risk factors in SLE. METHODS We examined for atherosclerotic plaques 460 individuals (92% female) without CVD history, using carotid and femoral artery ultrasound: 115 SLE patients and matched 1:1 for age and gender RA, DM, and control subjects. Multivariate models were used to determine relative risk estimates for the number of atherosclerotic plaques in patient groups versus controls, and associations of plaques with traditional CVD and disease-related factors in SLE. RESULTS A nearly two-fold higher number of atherosclerotic plaques in the carotid and femoral arteries was detected in each of SLE, RA and DM groups compared to controls, after adjusting for the effect of traditional CVD risk factors (RR=1.80, 95% CI 1.05-3.08, p=0.033, RR=1.90 (1.11-3.26), p=0.019, RR=1.93 (1.14-3.28), p=0.015, respectively). In SLE patients, the number of atherosclerotic plaques was associated with age (p<0.001), smoking (p=0.016), hypertension (p=0.029), and cumulative corticosteroid dose (p=0.007). CONCLUSION The relative risk of subclinical atherosclerosis in SLE was comparable to that found in RA and DM, indicating that SLE patients merit a similar diligence in CVD risk assessment and management measures.

Acute Hyperhomocysteinemia Impairs Endothelium Function in Subjects with Type 2 Diabetes Mellitus

The objective of the present study was to examine the effect of acute, methionine-induced hyperhomocysteinemia (HHCY) on endothelial function and indices of arterial stiffness in subjects with type 2 diabetes mellitus (T2DM). A total of 30 subjects with T2DM, free of macrovascular disease were examined in a crossover study. L-methionine (M) (0.1 g/kg) and water (W) load were given in random order with an interval of about 1 week in between. Endothelial function was assessed by flow-mediated vasodilation (FMD). Arterial stiffness was assessed by determination of augmentation index (AI). Measurements were performed in the fasting state, 1, 2 and 3 h after the M or the W load. Total plasma homocysteine (HCY) levels did not change after W administration, while M administration resulted in a significant increase in HCY concentrations at 3 h. FMD throughout the experiment expressed as area under the curve (AUC) was significantly lower after the M than after the W load. Consistent with impairment in endothelial function, the AUC of AI was significantly higher after the M than after the W administration. Acute HHCY impairs endothelial function and increases arterial stiffness in patients with T2DM. This effect is probably mediated by a reduction of nitric oxide bioavailability in endothelium.

Association between asymptomatic median mononeuropathy and diabetic polyneuropathy severity in patients with diabetes mellitus

BACKGROUND Asymptomatic median mononeuropathy (AMM) and diabetic polyneuropathy (DPN) often coexist and can be difficult to distinguish electrophysiologically. Moreover, the potential association between AMM and DPN has not been extensively evaluated. OBJECTIVE We investigated the relation between AMM and DPN severity in consecutive diabetic patients. METHODS The non-dominant limb was studied electrophysiologically in 100 consecutive diabetic patients with no symptoms of carpal tunnel syndrome on the non-dominant side. AMM was diagnosed based on previously validated electrophysiological criteria. DPN severity was graded according to the Michigan diabetic neuropathy score. RESULTS AMM was discovered in 28% of the study population (Adjusted Wald 95% CI: 20%-37%). It was more common in women, displayed a tendency of being more common in patients over 50 years old and correlated with the severity of DPN and the number of abnormal nerves on nerve conduction studies. It was present in 18.1% of patients without evidence of DPN. No correlation was found with the duration and type of diabetes. In multivariate logistic regression models increasing severity of DPN was independently associated with the presence AMM (Wald test=10.557, df=3, p=0.014). Patients with DPN stage III and IV had a five-fold (OR=5.06, 95% CI=1.49-17.19) and a four-fold (OR=4.50, 95% CI=1.15-17.65) respectively increased likelihood to present with AMM in comparison to DPN stage I (reference group). CONCLUSIONS Our results confirmed the high incidence of AMM in diabetic patients. AMM was present in a significant number of patients in the absence of DPN and the likelihood of AMM detection increased with increasing severity of DPN.

β2-Microglobulin, pulse pressure and metabolic alterations in hemodialysis patients.

Background/Aim: Pulse pressure (PP) is a result of arterial stiffness seen in dialysis patients, but may be a consequence of fluid overload. We examined the role of β2-microglobulin (β2M) in PP in relation to metabolic alterations in patients on different hemodialysis (HD) modalities. Methods: We studied 76 hemodialyzed patients on regular HD (n = 34), predilution bagged hemodiafiltration (n = 19) and online predilution hemodiafiltration (n = 23). β2M levels were measured by radioimmunoassay, and the clearance of β2M was assessed by Kt/V for β2M. Arterial stiffness was measured as carotid-femoral pulse wave velocity, and PP was derived. Insulin levels were measured using immunoradioassay, and insulin resistance was calculated using homeostasis model assessment insulin resistance (HOMA-IR). Serum bicarbonate levels were measured using a blood gas analyzer, and percent sodium removal was calculated. Results: β2M levels predict increased PP (p = 0.02) adjusting for age, HD modalities, HD duration, HOMA-IR and percent sodium removal. β2M was positively associated with HOMA-IR (r = 0.306, p = 0.007). Serum bicarbonate levels and carotid-femoral pulse wave velocity were inversely associated (r = –0.719, p = 0.001). Conclusions: β2M levels were positively associated with PP, which was influenced mainly by dialysis modality fluid and sodium balance and less by arterial stiffness. β2M levels were positively associated with insulin resistance. Uremic acidosis may contribute to arterial stiffness.

Anti-TNFα treatment for recalcitrant ulcerative necrobiosis lipoidica diabeticorum: A case report and review of the literature.

INTRODUCTION Necrobiosis lipoidica diabeticorum (NLD) is a rare degenerative connective tissue disorder associated with diabetes mellitus, which usually presents with red papules or plaques with raised edges and occasional ulceration. Ulcerating NLD is notoriously difficult to treat. We present a young patient with ulcerative NLD who was successfully treated with the anti-TNFα agent infliximab. Case presentation is followed by a review of therapeutic TNFα blockade in NLD. CASE PRESENTATION A 17-year old woman with type 1 diabetes since the age of 8, presented with a long-standing and extensively ulcerated and infected NLD lesion on her left shin. After achieving better glycemic control and treating her for infection of the wound, several NLD treatments failed to help, including corticosteroids and hyperbaric oxygen. She was treated successfully with 4 monthly sessions of 5mg/kg body weight intravenous infliximab, achieving complete resolution of ulceration. DISCUSSION A multitude of available treatments have been suggested for NLD over the past decades, based on two axes, one through wound healing and the other through immunosuppression. Anti-TNFα agents are relatively new drugs that brought a revolution in chronic inflammatory diseases and have been on the rise as novel potential treatments for NLD. Three out of the five available anti-TNFα agents have been safely tested so far, both topically and systematically, with mostly favorable results. CONCLUSION Intravenous infliximab was successful in the treatment of recalcitrant ulcerating NLD in our patient. Taken together with an increasing number of similar reports revealing a pathogenetic role of TNFα in NLD, we suggest that anti-TNFα agents are promising drugs in the management of this condition.

Efficacy of a New Heparan Sulfate Mimetic Dressing in the Healing of Foot and Lower Extremity Ulcerations in Type 2 Diabetes A Case Series

A novel heparan sulfate glycosaminoglycan mimetic product for local application to promote wound healing (CACIPLIQ) has recently become available. It is a biophysical therapeutic product comprising a polysaccharide as an innovative biomaterial to accomplish mechanical tissue engineering and skin regeneration in the site of ulceration. We present a series of 12 patients with type 2 diabetes (4 men and 8 women; age 53-87 years; diabetes duration 8-25 years) having chronic resistance to therapy for foot and lower extremity ulcerations. CACIPLIQ was locally applied twice per week after careful debridement. Complete ulcer healing was accomplished in all patients after a mean treatment duration of 4.92 months (range = 2-12 months). The product was very well tolerated. In conclusion, these results, although preliminary, are encouraging and suggest adequate efficacy and safety of the new product in difficult-to-heal foot and lower extremity ulcerations in type 2 diabetes.

Arterial Wall Elastic Properties and Endothelial Dysfunction in the Diabetic Foot Syndrome in Patients With Type 2 Diabetes

Diabetic foot (DF) syndrome is the most common lower-extremity complication of poorly controlled type 2 diabetes (T2D) (1). DF affects the quality of life of T2D patients and is associated with increased morbidity (2). T2D-related mechanisms induce endothelial dysfunction and adverse effects on vascular biology (3). We have recently shown that measurements of endothelial function and arterial stiffness are strongly associated with diabetic retinopathy (4), but their association with DF has not been explored yet. To examine this, we enrolled 284 consecutive T2D subjects visiting our outpatient diabetes clinic and 196 age- and sex-matched healthy control subjects without evidence of diabetes or cardiovascular or other disease. Subjects with known malignancy, hepatic impairment, or acute or chronic inflammatory disease were excluded from the study. Study protocol was approved by the institutional ethics committee. Endothelial function was assessed by the flow-mediated dilation (FMD) of the brachial artery and carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) were assessed by SphygmoCor (AtCor Medical) as …

The impact of T786C and G894T polymorphisms of eNOS on vascular endothelial growth factor serum levels in type 2 diabetes patients.

Endothelial dysfunction (ED) and chemokines such as vascular endothelial growth factor (VEGF) are of vital importance for the development of diabetic vascular complications [1–3]. VEGF is a secreted mitogen which plays a key role in the regulation of angiogenesis, vasculogenesis and vascular permeability to water and proteins [4]. Moreover, the action of VEGF is crucial for themaintenance of the proper endothelial and vascular function. The interaction between VEGF and its receptors is disrupted in diabetes, leading to pathological angiogenesis,which in turn contributes tomicrovascular diseases, such as diabetic retinopathy and diabetic nephropathy [5]. Nitric oxide (NO) is the most important regulator of vascular homeostasis and therefore, a common feature of ED is its diminished bioavailability in the vasculature [6,7]. In the setting of diabetes and insulin resistance, the activity of endothelial nitric oxide synthase (eNOS) is impaired, since insulin-mediated activation of eNOS via PI3kinase/Akt pathway is inhibited [8]. Moreover, diabetes mellitus (DM) enhances the production of reactive oxygen species (ROS), thus resulting in less NO generation and consequent vascular dysfunction [9,10].