Studies in animals show that fibroblast growth factor (FGF)-23 interferes with vascular reactivity induced by the nitric oxide (NO) system. To investigate the relationship between circulating FGF-23 levels and the response of forearm blood flow to ischemia (flow-mediated vasodilatation, FMD) and nitroglycerin, we tested 183 patients with stage 3-4 chronic kidney disease (CKD). None of them had cardiovascular complications or were taking drugs interfering with vascular function. Patients with FGF-23 levels above the median had significantly lower glomerular filtration rate, FMD, and fetuin-A levels (an anti-inflammatory molecule and potent inhibitor of calcification). They also had higher proteinuria and phosphate levels when compared to patients whose FGF-23 levels were below the median. The response to nitroglycerin was not different between the two groups. Multiple regression analysis showed that the relationship between FGF-23 and FMD was only modestly sensitive to adjustment for classical risk factors, biomarkers of bone mineral metabolism, high-sensitivity C-reactive protein, and homeostatic model assessment index. Adjustment for asymmetrical dimethyl arginine (ADMA) weakened the strength of this link; however, it remained highly significant. There was no independent association between FGF-23 and nitroglycerin. Thus, attenuation of FMD by ADMA suggests that this endogenous inhibitor of NO synthase may, in part, mediate the vascular effects of FGF-23 in patients with CKD.

Malfunction of permanent vascular accesses remains a cause of frequent and costly morbidity in patients receiving chronic hemodialysis (CHD). Several recommendations for routine monitoring of these permanent vascular accesses for incipient failure have been proposed. In this study, multiple indicators of incipient vascular access dysfunction, including "venous" and "arterial" pressures at serial blood flows (200 ml/min, 300 ml/min, and 400 ml/min), percent urea recirculation, Doppler ultrasound, and access blood flow by ultrasound dilution technique were simultaneously evaluated in a total of 220 vascular accesses in 170 chronic hemodialysis patients in two separate study periods (6 months apart). The rate of thrombosis was determined within the subsequent 12 weeks of each study period to assess the short-term predictive power of access thrombosis. During the period of follow-up, there were 34 thrombotic events in 172 polytetrafluoroethylene (PTFE) grafts and only one thrombotic event in 48 arterio-venous fistulas (AVF). Therefore, the statistical analysis was limited to the PTFE grafts. When grafts with thromboses were compared to those without thrombosis by univariate analysis, access blood flow measured either by ultrasound dilution technique (875 +/- 426 ml/min with thrombosis vs. 1193 +/- 677 ml/min without thrombosis, P = 0.001) or by Doppler ultrasound (762 +/- 420 ml/min with thrombosis vs. 1171 +/- 657 ml/min without thrombosis, P = 0.001) were significantly different in the two groups. There was good correlation (r = 0.79, P = 0.0001) between the blood flows determined by both techniques. The grade of stenosis determined by ultrasound was also a statistically significant predictor (P = 0.02). "Venous" and "arterial" pressures were numerically similar and were not statistically different between the accesses that did and those that did not thrombose. When multivariate analysis was used, there was a significantly increased risk of thrombosis only with decreasing access blood flow determined by ultrasound dilution techniques after adjusting for other confounding variables. When the average blood flow of all grafts (1134 ml/min) is considered as the reference access blood flow (relative risk of 1.0), the relative risk of a PTFE thrombotic event within the subsequent 12 weeks was 1.23 at a blood flow 950 ml/min, 1.67 at a blood flow of 650 ml/min and to 2.39 at a blood flow of 300 ml/min. In summary, access blood flow measured by either Dilution or Doppler is a reliable indicator of subsequent short-term thrombosis risk. Other proposed methods of evaluating access dysfunction were not useful in our patients. If simple to use, cost-effective devices to measure dialysis access blood flow become readily available, the measurement of access blood flow will likely become the method of choice for screening of PTFE vascular access dysfunction in hemodialysis patients.

Recognition of ARF and early beginning of the CVVHDF are extremely important. The sooner the ARF after surgery is recognized and CVVHDF is performed, the higher the likelihood of the reduction of the hospital mortality.

Background and objectives: Albuminuria and inflammation predict cardiovascular events. Pentraxin 3, an inflammatory mediator produced by, among others, endothelial cells, may have a role in atherogenesis.Design, setting, participants, & measurements: In 207 Swedish patients with stage 5 chronic kidney disease and 79 Turkish patients with type 2 diabetes and proteinuria and normal renal function, whether serum pentraxin 3 levels are associated with albuminuria and endothelial dysfunction was studied.Results: Patients with stage 5 chronic kidney disease and a high degree of albuminuria more often had diabetes and higher levels of pentraxin 3, vascular cellular adhesion molecule-1, and blood pressure. Moreover, pentraxin 3 was independently associated with 24-h urinary albumin excretion. In patients with type 2 diabetes, pentraxin 3 was significantly higher than in control subjects. Patients with type 2 diabetes and more proteinuria had higher pentraxin 3, C-reactive protein, glycosylated hemoglobin, insulin, and homeostasis model assessment index as well as lower flow-mediated dilation and serum albumin. Pentraxin 3 was positively correlated with C-reactive protein, homeostasis model assessment index, and carotid intima-media thickness and negatively with flow-mediated dilation. Pentraxin 3 and glomerular filtration rate were independently associated with 24-h urinary protein excretion. Only pentraxin 3 and proteinuria were significantly and independently associated with flow-mediated dilation.Conclusions: In two different renal cohorts, one of stage 5 chronic kidney disease and one of type 2 diabetes and normal renal function, pentraxin 3 was independently associated with proteinuria. Moreover, both pentraxin 3 and proteinuria were associated with endothelial dysfunction in patients with type 2 diabetes.

Background: Magnesium is an essential ion for all living cells because over 300 enzymes require the presence of magnesium for their catalytic action. To date, no group has evaluated magnesium as a cardiovascular risk factor in chronic kidney disease (CKD) subjects, in which closely interrelated factors and potential confounders such as endothelial dysfunction, insulin resistance (the homeostasis model assessment (HOMA) index) and inflammation (expressed as serum C-reactive protein (CRP) levels) were also considered. Methods: Between March 2006 and December 2010, 283 CKD patients were followed up for time-to-event analysis until the occurrence of fatal or nonfatal cardiovascular events. Endothelium-dependent vasodilatation (flow-mediated dilatation; FMD) and endothelium-independent vasodilatation (nitroglycerin-mediated dilatation) of the brachial artery were assessed noninvasively using high-resolution ultrasound. Results: From the univariate analysis of FMD, it appears that a higher magnesium level is associated with less endothelial dysfunction. When a multivariate analysis was performed, magnesium and estimated glomerular filtration rates (eGFR) maintained a strong positive correlation with FMD, supporting the hypothesis that higher levels of magnesium may protect against endothelial damage. In univariate Cox proportional hazards models, FMD, magnesium, high sensitivity CRP, the HOMA index, eGFR, comorbid diabetes, hypertension, smoking status, systolic blood pressure, serum phosphate and intact parathormone emerged as significant predictors for cardiovascular outcomes. Kaplan-Meier curves showed significantly higher cardiovascular mortality rates in CKD patients whose serum magnesium levels were below 2.05 mg/dl. Conclusions: This observational cohort study showed that magnesium may be an independent predictor of future cardiovascular outcomes and is the first study demonstrating such a role in etiologically diagnosed CKD patients, across different stages.

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SummaryBackground and objectives Deterioration of kidney function impairs testosterone production, with hypogonadism being common in men with chronic kidney disease (CKD). In nonrenal populations, testosterone is suggested to participate in the atherosclerotic process. In male dialysis patients, we showed that low testosterone increases the risk of mortality. We here studied plausible links among testosterone levels, vascular derangements, and cardiovascular events in nondialysis CKD men.Design, setting, participants, & methods This was a cross-sectional analysis in which flow-mediated dilation (FMD) was assessed in 239 CKD male patients (stages 1 to 5; mean age 52 Ϯ 12 years), together with routine measurements, serum total and free testosterone, and follow-up for cardiovascular outcomes.Results Total and free testosterone levels decreased in parallel with the reduction of kidney function. Multiple regression analyses showed that total and free testosterone significantly and independently contributed to explain the variance of FMD. After a median follow-up of 31 months (range 8 to 35 months), 22 fatal and 50 nonfatal cardiovascular events occurred. In Cox analysis, the risk of cardiovascular events was reduced by 22% for each nanomole-per-liter increment of total testosterone. This reduced risk persisted after adjustment for age, renal function, diabetes mellitus, previous cardiovascular history, C-reactive protein, albumin, and FMD. The same was true for free testosterone concentrations. ConclusionsThe reduction in endogenous testosterone levels observed with progressive CKD was inversely associated with endothelial dysfunction and exacerbated the risk of future cardiovascular events in nondialysis male CKD patients.

SummaryBackground and objectives Chronic kidney disease (CKD) conveys high mortality rates. Soluble TNF-like weak inducer of apoptosis (sTWEAK) and long pentraxin 3 (PTX3) are predictors of mortality in dialysis patients and determinants of endothelial dysfunction. Now, we hypothesize that both sTWEAK and PTX3 act as biomarkers of cardiovascular outcomes in nondialysis CKD patients.Design, setting, participants, & measurements Cross-sectional analysis in which flow-mediated dilation (FMD) and intima-media thickness (IMT) were assessed in 257 nondialysis stage 1 to 5 CKD patients (mean age, 52 Ϯ 12 years; 130 men), together with biochemical measurements and sTWEAK and PTX3 assessments. Patients were followed for cardiovascular outcomes.Results PTX3 and IMT increased, whereas FMD and sTWEAK decreased across CKD stages (P Ͻ 0.001 for all). Both PTX3 and sTWEAK appeared as strong determinants of FMD in multivariate analysis. The univariate associations of sTWEAK and PTX3 with IMT were dependent on estimated GFR. After a median of 39 months (range, 2 to 43 months), 22 fatal and 57 nonfatal cardiovascular events occurred. In a Cox model excluding PTX3, decreasing sTWEAK concentration was associated with increased risk of cardiovascular events independently of basic confounders (age, gender, estimated GFR, C reactive protein, diabetes, and cardiovascular comorbidity) and FMD. In a model excluding sTWEAK, circulating levels of PTX3 were directly associated with cardiovascular outcomes independently of basic confounders, but this association was lost after adjustment for FMD.Conclusions Both PTX3 and sTWEAK levels associated with the endothelial dysfunction observed with progressive kidney failure. Additionally, both biomarkers impacted the predictability of cardiovascular outcomes.