Relationship between vascular cell adhesion molecule-1 (VCAM-1), soluble receptor for advanced glycation end products (sRAGE) and functional hemodynamic parameters of arteriovenous fistula.

BACKGROUND: The preferred vascular access for hemodialysis is represented by arteriovenous fistula (AVF) due to fewer complications and more prolonged survival. Considerable efforts have been made to identify biomarkers associated with AVF dysfunction, but results are conflicting. Vascular cell adhesion molecule (VCAM-1) and advanced glycation end products are involved in atherogenesis, vascular calcification, peripheral artery disease, and neointimal hyperplasia in renal and non-renal patients. The objective of this study was to evaluate whether there is an association between VCAM-1, soluble receptor for advanced glycation end products (sRAGE), NcarboxymethylLysine (CML), and arteriovenous fistula dysfunction (AVF). METHODS: VCAM-1, sRAGE, and CML were performed using the ELISA technique in 88 HD patients. Ultrasound assessment of AVF reports brachial artery blood flow (Qa), brachial resistivity index (RI), presence of calcification, and the diameter. AVF dysfunction was defined as a brachial artery Qa ⩽ 500 ml/min or RI ⩾ 0.5. RESULTS: The median level of VCAM-1 [2676.5(2206.8-4203.9) versus 2613.2(1885.7-3161.8), p 0.026] was significantly higher in patients with AVF dysfunction compared to the rest of the patients. sRAGE and CML were higher in this group but without statistical significance. In patients with AVF dysfunction, significant positive correlations were found between VCAM-1and sRAGE (r = 0.417, p = 0.001), RI (r = 0.313, p = 0.046), dialysis vintage (r = 0.540, p < 0.001), AVF vintage (r = 0.336, p = 0.032), intima-media thickness (r = 0.423, p = 0.006) and C-reactive protein (r = 0.315, p = 0.045). VCAM-1 correlated inversely with cholesterol (r = -0.312, p = 0.047), triglycerides (r = -0.358, p = 0.021), body mass index (r = -0.388, p = 0.012). In multivariate regression analysis, VCAM-1 (p = 0.013) and sRAGE (p = 0.01) remained significant predictors of RI and Qa. Logistic regression disclosed calcification, VCAM-1, as risks factors for AVF dysfunction. CONCLUSION: The results we obtained showed that patients with AVF dysfunction had a significantly higher level of VCAM-l. A positive correlation between VCAM-1 and sRAGE was identified in this group.

Arterial calcifications and osteoprotegerin in chronic hemodialysis patients: impact on 6-year survival.

AIM: The association between end-stage renal disease and cardiovascular mortality may be influenced through vascular alterations, in particular atherosclerosis and vascular calcification. The study goal was to assess the impact of each type of arterial intimal calcifications (AIC) and arterial medial calcifications (AMC), of osteoprotegerin (OPG), mineral metabolism markers and other features on all-cause and cardiovascular mortality in chronic hemodialysis patients. METHODS: Ultrasound was performed in 87 patients on the carotid and femoral arteries, and the severity of AIC and AMC was assessed calculating a score according to the extension of calcification. We analyzed the link between AIC, AMC, OPG, mineral markers and mortality after 6 years of follow-up. RESULTS: The cutoff value for OPG determined using ROC was 4.9 pmol/l for all-cause and cardiovascular mortality. Patients with higher serum OPG levels presented higher mortality rates. Our study revealed that AIC, high OPG, low ankle-arm index, presence of diabetes, smoking status, and lack of arteriovenous fistula are associated with all-cause and cardiovascular mortality in univariate regression analysis. Multivariate analysis identified AIC scoring based on the segmentation method as an independent predictor of all-cause and cardiovascular mortality, along with increased OPG levels. AMC scoring was not a predictor of mortality. CONCLUSIONS: Identifying and scoring AIC on ultrasound and measuring OPG levels, as a basis of the HD patient assessment may become valuable tools in clinical work, as these have an impact on death toll.

Hemodialysis Patients with Higher Serum Levels of Soluble Receptor for Advanced Glycation End Products Have an Increased Risk for Arteriovenous Fistula Failure.

BACKGROUND: Arteriovenous fistula (AVF) failure due to thrombosis is a major cause of morbidity in patients undergoing regular hemodialysis (HD). Advanced glycation end products (AGEs) and their receptor (RAGE) might contribute to inflammation, neointimal hyperplasia, and thrombosis. RAGE has a C-truncated secretory receptor form, called soluble RAGE (sRAGE). In this study, we aimed to evaluate the association of serum sRAGE with AVF failure due to thrombosis in HD patients. METHODS: Eighty-eight prevalent HD patients with functional AVF were included in the study. The presence of stenosis, clinical and laboratory data, and serum sRAGE was evaluated at inclusion. sRAGE concentration was measured by a competitive enzyme-linked immunosorbent assay, and stenosis was detected by ultrasound. Patients were prospectively followed up for 36 months. During this period, AVF failure (defined as the absence of blast or palpable thrill and impossible cannulation with 2 needles because of complete thrombosis) was noted and thrombosis was certified by ultrasound examination. RESULTS: During follow-up, 16 (18.18%) patients lost their vascular access due to thrombosis. In multivariate Cox regression analysis, sRAGE was a significant predictor of vascular access thrombosis (hazard ratio = 1.15, 95% confidence interval: 1.03-1.25, p = 0.012). Kaplan-Meier analysis showed a significantly lower AVF patency time in patients with sRAGE >16.78 ng/mL than those with sRAGE <16.78 ng/mL (p = 0.02). In the subgroup of patients with stenosis at baseline, sRAGE, serum albumin, obesity, and ischemic heart disease were associated with thrombosis. CONCLUSION: In our study, baseline, systemic sRAGE is associated with the occurrence of thrombosis of AVF, and this marker has a significant impact on AVF survival.

Synthesis of Fluorescent Dansyl Derivatives of Methoxyamine and Diphenylhydrazine as Free Radical Precursors.

Starting from dansyl-chloride, in reaction with 1,1-diphenylhydrazine and methoxyamine, two new fluorescent derivatives 1 and 2 were obtained and characterized by NMR, IR, UV-Vis, HR-MS, and fluorescence spectroscopy. The single-crystal X-ray structure was obtained for compound 2. Both compounds generate free radicals by oxidation, as demonstrated by ESR spectroscopy. Compound 1 generates the corresponding hydrazyl-persistent free radical, evidenced directly by ESR spectroscopy, while compound 2 generates in the first instance the methoxyaminyl short-lived free radical, which decomposes rapidly with the formation of the methoxy radical, evidenced by the ESR spin-trapping technique. By oxidation of compounds 1 and 2, their fluorescence is quenched.

A polycarboxylic chelating ligand for efficient resin purification of His-tagged proteins expressed in mammalian systems.

We describe the synthesis of a novel polyamino polycarboxylic ligand, its ability to coordinate metal-ions and attachment to a solid support designed for protein purification through Immobilised Metal-ion Affinity Chromatography (IMAC). The resin was found to be highly efficient for purification of His-tagged HCV E2 glycoproteins expressed in 293T mammalian cells.

A novel adaptive fluorescent probe for cell labelling.

In this study we describe the synthesis and characterisation of a new hydrazone-based fluorescent compound that is able to selectively label the endoplasmic reticulum (ER) in yeast and mammalian living cells. The fluorescence properties of the compound depended on the DMSO/water ratio and on the pH. NMR experiments allowed determination of the conformation adopted in various environments. Apart from the convenient synthetic procedure, our compound displays low cell toxicity and blue emission compatible with filters routinely used in fluorescence microscopy.

Pentosidine in chronic hemodialysis patients: relation with arteriovenous fistula morphology and function.

PURPOSE: It has been suggested that advanced glycation end products (AGEs) are involved in atherogenesis, vascular calcification and remodeling, including neointimal hyperplasia, in renal and non-renal patients. Their relevance for arteriovenous fistula (AVF) function has been poorly studied to date, with only one clinical study addressing the issue of thrombosis of vascular access in relation to AGEs in dialysis patients. We aimed to evaluate the relationship between serum pentosidine and AVF morphology and function. METHODS: Eighty-eighth hemodialysis patients with patent native AVF were included. Ultrasound examination of AVF evaluated blood flow in the brachial artery, resistivity index (RI), the diameter of the vessels and the presence of stenosis. AVF and cardiovascular history were recorded, routine clinical and laboratory evaluation was performed and serum pentosidine was assessed. RESULTS: Forty-eight patients (54.54%) had AVF stenosis. Pentosidine correlated in univariate analysis with cholesterol (r = 0.270, p = 0.01), triglycerides (r = 0.309, p = 0.003), calcium (r = 0.040, p < 0.001) and inversely to dialysis vintage (r = - 0.453, p < 0.001), access vintage (r = - 0.432, p = 0.001), phosphate (r = - 0.211, p = 0.04), parathyroid hormone (r = - 0.211, p = 0.04), urea (r = - 0.230, p = 0.03), residual diameter of AVF (r = - 0.023, p = 0.03). In multivariate regression calcium (p = 0.006), access vintage (p = 0.03), and residual diameter of AVF vein (p = 0.02) remain significantly linked to pentosidine. Patients with pentosidine above median had higher cholesterol (179.91 vs. 160.97, p = 0.04), triglycerides (187.18 vs. 129.31, p = 0.002) and higher prevalence of hypertension (93.70% vs. 84.10%, p = 0.02). CONCLUSIONS: Our study suggests that pentosidine could be associated to vascular access morphology and function in dialysis patients.

A novel profluorescent paramagnetic diaza-crown ether: synthesis, characterization and alkaline metal-ion complexation.

Starting from Kryptofix 22 two different branches were covalently attached through the nitrogen atoms, one containing a fluorescent moiety and the other the stable free radical TEMPO. The novel derivative exhibits fluorescence and paramagnetic properties, while the diaza-crown part ensures the affinity for alkaline metal-ions.

Determinants of visfatin in type 2 diabetes patients with diabetic kidney disease: Relationship to inflammation, adiposity and undercarboxylated osteocalcin.

BACKGROUND: Visfatin is a proinflammatory molecule with possible actions on glucose metabolism. Interactions to bone metabolism and undercarboxylated osteocalcin (uOC) in diabetic patients (T2DP) with diabetic kidney disease (DKD) have not been reported. MATERIALS AND METHODS: We included 51 incident T2DP with DKD. History, laboratory evaluation, anthropometry, visfatin, uOC were obtained. Fifteen T2DP without DKD were used as controls. RESULTS: Visfatin was similar in DKD patients and controls: 1.56(0.97-3.03) versus 2.04(1.08-3.21) ng/mL, p = 0.51. In controls, visfatin positively correlated with diabetes duration (r = 0.63, p = 0.01) and negatively with uOC (r = -0.57, p = 0.03). In multivariate regression, diabetes duration remained significant (p = 0.01). In patients with DKD, visfatin was positively linked to C reactive protein (r = 0.27, p = 0.05), tricipital skin fold (TSF) (r = 0.41, p = 0.004) and leukocytes (r = 0.37, p = 0.01); the latter two parameters predicted visfatin in multivariate model (p = 0.001). In normoalbuminuric patients, visfatin was linked to body mass index (r = 0.32, p = 0.04), waist circumference (r = 0.42, p < 0.0001), LDL cholesterol (r = 0.33, p = 0.03), serum glucose (r = 0.36, p = 0.03) and glycated hemoglobin (r = 0.41, p = 0.007); there was a trend towards negative correlation to uOC (r = -0.28, p = 0.07); only glycaemia remained significant in multivariate analysis (p = 0.04). Albuminuric patients displayed a positive correlation of visfatin to waist to hip ratio (r = 0.41, p = 0.04) and leukocytes (r = 0.56, p = 0.04); the latter remained significant in multivariate regression (p = 0.005). CONCLUSION: The main determinant of visfatin in T2D patients with DKD is inflammation; in normoalbuminuric patients, a positive link to adiposity and altered glycemic control and a trend towards a negative correlation to uOC was observable; the latter relationship was evident in patients without DKD.

Diet and paraoxonase 1 enzymatic activity in diabetic foot patients from Romania and Belgium: favorable association of high flavonoid dietary intake with arylesterase activity.

BACKGROUND/AIMS: The antiatherosclerotic enzyme paraoxonase (PON1) is affected by disease and lifestyle. We investigated the impact of diet in diabetic foot patients from 2 European countries. METHODS: Dietary intake and serum PON1 activity, using as substrate paraoxon (paraoxonase) or phenylacetate (arylesterase), were assessed in patients from Bucharest (n = 40) and Antwerp (n = 30) and in 34 healthy controls. RESULTS: The diabetic patients had lower paraoxonase and arylesterase activities than the controls. Arylesterase was lowest in the Bucharest patients, 116 +/- 42 U/ml, versus 141 +/- 43 and 184 +/- 49 U/ml in the Antwerp patients and controls, respectively (p < 0.0005). The Bucharest patients had worse glycemic control, higher blood pressure, lower HDL cholesterol and a diet richer in cholesterol and poorer in monounsaturated fats and fish. In contrast, their median intake of vitamins E and C, folic acid and flavonoids was higher, 82 mg (range: 4-259 mg), versus 28 mg (range: 5-169 mg) aglycone units in Antwerp (p = 0.005). Flavonoid intake predicted arylesterase independently of HDL cholesterol, region and sex (beta = 0.27; p = 0.03), and patients with high intake achieved normal levels of arylesterase (30.1 +/- 10.0 U/micromol in the highest versus 21.0 +/- 8.2 U/micromol total cholesterol in the lowest tertile; p = 0.02). CONCLUSION: A flavonoid-rich diet is positively associated with PON1 arylesterase activity in diabetic foot patients.

Diabetic foot patients with and without retinopathy and plasma oxidative stress.

OBJECTIVE: The first aim of this study was to evaluate some plasma oxidative stress markers in diabetic patients (type2 diabetes mellitus) with peripheral arteriopathy. Secondly, these patients were divided into two groups considering the presence or absence of retinopathy. The differences in the levels of the oxidative stress parameters could be important to select patients prone to develop multiple vascular complications, including retinopathy. PATIENTS AND METHODS: Forty hospitalized type II diabetic patients, aged between 40 and 70, with stage III or IV foot ulceration according to the Wagner classification, had an ophthalmologic evaluation for retinopathy. Among them, 23 were with retinopathy with different grades of severity and 17 were without retinopathy. Twenty healthy subjects served as a control group. Fasting plasma glucose, glycosylated hemoglobin, serum fructosamine, total serum proteins, serum uric acid and plasma ceruloplasmin levels were determined and compared. RESULTS: Plasma levels for fasting glucose, glycosylated hemoglobin, ceruloplasmin and serum concentrations for fructosamine and uric acid were significantly increased in diabetic foot patients vs. control subjects. Comparing the two groups of patients, with and without retinopathy, the concentrations of ceruloplasmin and uric acid were significantly increased in diabetic patients with retinal disease. In diabetic patients with retinopathy, positive correlations were calculated between glycated hemoglobin and fructosamine concentrations and between glycated hemoglobin and ceruloplasmin. CONCLUSION: Diabetic foot patients with retinopathy have increased plasma levels of uric acid and ceruloplasmin. These plasma compounds could be important in the pathogenesis of retinal disease. Two aspects should be considered when these high values are analysed. First, these antioxidant compounds may become prooxidant in diabetic vascular environment. Secondly, it is not known whether these modified plasma oxidative stress parameters are cause or effect in diabetic complication development.

The influence of sodium metavanadate on the process of diabetogenesis in BB rats.

Vanadium has been shown to be beneficial in the oral treatment of animal models of type 1 and type 2 diabetes. The aim of the study was to evaluate the short-term effects of sodium metavanadate in prediabetic BB-DP rats. To do this, 96 rats were divided into 4 equal groups. Groups V1, V2, V3 were treated with sodium metavanadate (0.1, 0.2 and 0.3 mg/ml respectively) and sodium chloride (0.5 mg/ml) in drinking water for 7 days. Group C received only sodium chloride (0.5 mg/ml). Blood glucose (BG), glycosuria, ketonuria, body weight and insulinemia were determined. The age of onset of diabetes was significantly higher for groups V2, V3 compared to group C, (p<0.05) and depends on the metavanadate concentration (V3 vs. V1, p=0.006). The incidence of diabetes was lower in the rats treated with metavanadate than in the control group, but this difference was not statistically significant. In diabetic rats, the BG at the onset was higher in group C than in groups V, p<0.05. Insulinemia, at the onset of the treatment as well as immediately after its cessation showed a drop in the treatment groups, proportionally to the dosage of vanadium, but later increased slowly and continuously until the end of the experiment. In conclusion, metavanadate delays the development of diabetes in BB-DP rats, but does not prevent its onset. A milder form of diabetes occurs in diabetic rats treated with metavanadate. The effects depend on the metavanadate concentration and 0.2 mg/ml is preferable.