Search

Background/Objectives: Chronic kidney disease (CKD) and end-stage kidney disease (ESKD) are significant public health issues, with cardiovascular morbidity and mortality being the leading causes of death in hemodialysis patients. Osteopontin (OPN), a multifunctional glycoprotein, has emerged as a potential biomarker for vascular disease in CKD due to its role in inflammation, tissue remodeling, and calcification. Methods: This cohort study included 1124 hemodialysis patients from the PROGREDIRE study, a registry involving 35 dialysis units in Southern Italy. Serum osteopontin levels were measured using enzyme-linked immunosorbent assay (ELISA). The primary endpoints were all-cause and cardiovascular mortality. Multivariate Cox regression analyses were performed to assess the association between osteopontin levels and mortality, adjusting for traditional risk factors, biomarkers of inflammation, nutritional status, and ESKD-related factors. Results: During a mean follow-up of 2.8 years, 478 patients died, 271 from cardiovascular causes. Independent correlates of osteopontin included alkaline phosphatase and parathyroid hormone. Elevated osteopontin levels were significantly associated with increased all-cause mortality (HR 1.19, 95% CI 1.09–1.31, p < 0.001) and cardiovascular mortality (HR 1.22, 95% CI 1.08–1.38, p = 0.001) after adjusting for confounders. Conclusions: Elevated osteopontin levels are associated with increased all-cause and cardiovascular mortality in hemodialysis patients. These findings implicate osteopontin in the high risk for death and cardiovascular disease in the hemodialysis population. Intervention studies are needed to definitively test this hypothesis. [ABSTRACT FROM AUTHOR]

Background: Proprotein convertase subtilisin/kexin type 9 (PCSK9), a factor accelerating the degradation of LDL receptors, was associated with a gender‐dependent risk for cardiovascular (CV) events in the general population and with all‐cause and CV mortality in two relatively small studies in black Africans and South Korean haemodialysis patients. The effect modification by gender was untested in these studies. Methods: The study enrolled 1188 dialysis patients from the Prospective Registry of The Working Group of Epidemiology of Dialysis Region Calabria (PROGREDIRE) cohort. PCSK9 was measured by colorimetric enzyme‐linked immunosorbent assay. The primary outcomes were all‐cause and CV mortality. Statistical analysis included Cox regression analysis and effect modification analysis. Results: During a median 2.9‐year follow‐up, out of 494 deaths, 278 were CV‐related. In unadjusted analyses, PCSK9 levels correlated with increased all‐cause (HRfor1ln unit increase: 1.23, 95% CI 1.06–1.43, p =.008) and CV mortality (HRfor1ln unit increase: 1.26, 95% CI 1.03–1.54, p =.03). After multivariate adjustment, these associations were no longer significant (all‐cause mortality, HRfor 1 ln unit increase: 1.16, 95% CI.99–1.36, p =.07; CV mortality, HRfor1ln unit increase: 1.18, 95% CI.95–1.46, p =.14). However, in fully adjusted interaction analyses, a doubling in the risk of this outcome in women was registered (Women, HRfor1ln unit increase: 1.88, 95% CI 1.27–2.78, p =.002; Men, HRfor1ln unit increase: 1.07, 95% CI.83–1.38, p =.61; p for effect modification:.02). Conclusions: PCSK9 levels are unrelated to all‐cause mortality in haemodialysis patients but, like in studies of the general population, independently of other risk factors, entail a doubling in the risk of CV events in women in this population. [ABSTRACT FROM AUTHOR]

Background and Objectives: Acute kidney injury (AKI) remains a significant complication following major cardiac surgery. Marinobufagenin (MBG), a cardiotonic steroid involved in sodium balance and blood pressure regulation, has been linked to organ damage after ischemia–reperfusion events. This pilot, prospective study investigates the utility of circulating MBG to improve AKI risk assessment in cardiac surgery patients as a stand-alone biomarker and after inclusion in a validated risk model (STS-AKI score). Materials and Methods: We included 45 patients undergoing elective cardiac surgery. The MBG levels were measured preoperatively and at 4, 8, and 12 h post-surgery. The AKI was defined according to the KDIGO guidelines. Statistical analyses assessed the diagnostic and prognostic utility of MBG and its integration with the STS-AKI score. Results: An AKI occurred in 26.7% of the patients. The STS-AKI score performed well in this cohort (AUC: 0.736). The MBG levels displayed a decreasing trend in the whole population after surgery (p = 0.02). However, in the AKI patients, MBG increased at 4 and 8 h before decreasing at 12 h post-surgery. The MBG changes from the baseline to 8 h and from 8 to 12 h post-surgery showed a remarkable diagnostic accuracy for an AKI (AUCs: 0.917 and 0.843, respectively). Integrating these MBG changes with the STS-AKI score significantly improved the model performance, including discrimination, calibration, and risk reclassification. Conclusions: The MBG measurement, particularly any dynamic changes post-surgery, enhances AKI risk stratification in cardiac surgery patients. Integrating MBG with the STS-AKI score offers more accurate risk predictions, potentially leading to better patient management and outcomes. [ABSTRACT FROM AUTHOR]

Background: Chronic Kidney Disease (CKD) is a complex health condition that interacts significantly with socioeconomic determinants, particularly income status and education. This study developed a simple indicator of socioeconomic status (SES), which is composed of income status and education in CKD patients, and evaluated its impact on health outcomes in this population. Methods: This study was conducted on 561 CKD patients, stages 2–5. The composite SES score was developed by combining the regression coefficients of income and education as predictors of the study endpoint in a multivariable Cox model, normalizing these coefficients to derive weights, and then using these weights to calculate an individual percentage score based on each person's income and education. The composed SES indicator was internally validated through bootstrap analysis. Over a median follow-up time of 36 months, we tracked all-cause death and non-fatal cardiovascular events. Results: Both lack of income (p = 0.020) and low educational level (p = 0.034) were independently related to the combined endpoint. Based on these covariates' regression coefficients, a composite socioeconomic score considering income and educational level was generated. In a Cox regression model, a 10% increase in this composite risk score entailed a 25% increase in the hazard ratio (HR) of the combined endpoint [HR (10% increase): 1.25], and the internally validated 95% CI ranged from 1.14 to 1.41 (p < 0.001). Conclusions: This study underscores the significant impact of a simple, bootstrap-validated composite SES indicator on CKD patients' health outcomes. These findings highlight the importance of considering education and socioeconomic factors in managing and treating CKD patients and inform future research and policy considerations for this population. [ABSTRACT FROM AUTHOR]

Background: Biomarkers development for prognostication or prediction of perioperative myocardial disease is critical for the evolution of treatment options in patients undergoing cardiac surgery. The aim of our prospective monocentric study was to investigate the role of selenoprotein 1 (SEEP 1) as a potential biomarker for assessing the risk of myocardial injury after cardiac surgery. Methods: Circulating SEPP1 was measured in the blood of 45 patients before surgery and at 4 h, 8 h and 12 h after CPB by enzyme-linked immunosorbent assay (ELISA); (3) Results: circulating SEPP-1 levels measured 4 h after surgery were strongly correlated with CK-MB levels measured at 48 h (R = 0.598, p < 0.0001) and at 72 h (R = 0.308, p = 0.05). Close correlations were also found between 4 h SEPP-1 and Hs-c troponin values measured at 24 h (R = 0.532, p < 0.0001), 48 h (R = 0.348, p = 0.01) and 72 h (R = 0.377, p = 0.02), as well as with cardiopulmonary bypass (CPB) (R = 0.389, p = 0.008) and cross-clamp time (R = 0.374, p = 0.001); (4) Conclusions: Early SEPP1 measurement after CPB may hold great potential for identifying cardiac surgery patients at risk of developing perioperative myocardial injury. [ABSTRACT FROM AUTHOR]

Although the gut microbiota is known to affect body weight, its relationship with overweight/obesity is unclear. Our aim was to characterize microbiota composition in a cohort from the southernmost area of Italy. We investigated whether an altered gut microbiota could play an etiological role in the pathogenesis of overweight/obesity. A total of 163 healthy adults were enrolled. Microbiome analysis was performed via 16S rRNA gene sequencing. We found significant phylum variations between overweight (N = 88) and normal-weight (N = 75) subjects. Bacteroidetes and Proteobacteria were higher in overweight participants (p = 0.004; p = 0.03), and Firmicutes and Verrucomicrobia were lower (p = 0.02; p = 0.008) compared to normal-weight participants. Additionally, Akkermansia and Bifidobacterium (genus level) were significantly lower in the overweight group, as well as Akkermansia muciniphila at the species level. The Firmicutes/Bacteroidetes ratio (F/B ratio), an index of dysbiosis, was found to be inversely associated with BMI in linear and logistic regression models (p = 0.001; p = 0.005). The association remained statistically significant after adjustment for potential confounders. This cross-sectional study contributes to defining the gut microbiota composition in an adult population living in southern Italy. It confirms the relationship between overweight susceptibility and the dysbiosis status, highlighting the possible etiological role of the F/B ratio in disease susceptibility. [ABSTRACT FROM AUTHOR]

Background Biomarkers of chronic kidney disease–mineral and bone disorder (CKD-MBD) have been implicated in CKD progression in follow-up studies focusing on single measurements of individual biomarkers made at baseline only. The simultaneous relationship between the time trend of these biomarkers over the course of CKD and renal outcomes has never been tested. Methods We applied the joint model (JM) to investigate the longitudinal relationship between repeated measurements of CKD-MBD biomarkers and a combined renal endpoint (estimated glomerular filtration rate reduction >30%, dialysis or transplantation) in 729 stage 2–5 CKD patients over a 36-month follow-up. Results In the survival submodel of the JM, the longitudinal series of parathyroid hormone (PTH) values was directly and independently related to the risk of renal events [hazard ratio (HR) (1 ln increase in parathyroid hormone (PTH) 2.0 (range 1.5–2.8), P  < .001)] and this was also true for repeated measurements of serum phosphate [HR (1 mg/dl) 1.3924 (range 1.1459–1.6918), P  = .001], serum calcium [HR (1 mg/dl) 0.7487 (range 0.5843–0.9593), P  = .022], baseline fibroblast growth factor 23 [HR (1 pg/ml) 1.001 (range 1.00–1.002), P  = .045] and 1,25-dihydroxyvitamin D [HR (1 pg/ml) 0.9796 (range 0.9652–0.9942), P  = .006]. Conclusion Repeated measurements of serum PTH, calcium and phosphate as well as baseline FGF23 and 1,25-dihydroxyvitamin D are independently related with the progression to kidney failure in a cohort of stage 2–5 CKD patients. This longitudinal study generates the hypothesis that interventions at multiple levels on MBD biomarkers can mitigate renal function loss in this population. [ABSTRACT FROM AUTHOR]

Background: Acute Kidney Injury (AKI) is a frequent, dangerous complication in patients undergoing cardiopulmonary bypass (CPB) with oxidative stress playing a crucial role. In this pilot study we evaluated the possible role of the selenoprotein-p1 (SEPP1), a circulating, anti-oxidant selenium transporter, as a predictive biomarker of AKI in this population setting. Methods: Circulating SEPP1 was measured in the blood of 45 patients before surgery and at 4 h, 8 h and 12 h after CPB by Enzyme-Linked Immunosorbent Assay (ELISA). Results: SEPP1 increased from 69 [IQR 39--85] to 3263 [IQR 1886.2--5042.7] ng/mL (p for trend<0.0001). AKI occurred in 26.7% of patients. In these individuals, an earlier and more prominent increase in SEPP1 was observed at 4 h and 8 h, as compared with those not experiencing AKI (difference between trends p < 0.0001). Logistic regression analyses evidenced 4 h and 8 h SEPP1 as significantly associated with AKI (OR 1.035; 95% CI 1.002--1.068; p = 0.03 and 1.011; 95% CI 1.002--1.021; p = 0.02, respectively). ROC analyses displayed a remarkable discriminatory capacity of early SEPP1 measurements in identifying AKI (AUCs ranging from 0.682 to 0.854; p from 0.04 to <0.0001). In addition, 12 h-SEPP1 showed diagnostic capacity to identify patients reaching a secondary composite endpoint including major adverse kidney events (MAKEs). Conclusions: Findings from this pilot, exploratory study suggest that early SEPP1 measurement after CPB may hold great potential for improving renal risk stratification in cardiac surgery patients. Further studies in wider and more heterogeneous cohorts are needed to generalize these findings and to evaluate a possible applicability in daily practice. [ABSTRACT FROM AUTHOR]

Background Adherence to low salt diets and control of hypertension remain unmet clinical needs in chronic kidney disease (CKD) patients. Methods We performed a 6-month multicentre randomized trial in non-compliant patients with CKD followed in nephrology clinics testing the effect of self-measurement of urinary chloride (69 patients) as compared with standard care (69 patients) on two primary outcome measures, adherence to a low sodium (Na) diet (<100 mmol/day) as measured by 24-h urine Na (UNa) excretion and 24-h ambulatory blood pressure (ABPM) monitoring. Results In the whole sample (N  = 138), baseline UNa and 24-h ABPM were143 ± 64 mmol/24 h and 131 ± 18/72 ± 10 mmHg, respectively, and did not differ between the two study arms. Patients in the active arm of the trial used >80% of the chloride strips provided to them at the baseline visit and at follow-up visits. At the third month, UNa was 35 mmol/24 h (95% CI 10.8–58.8 mmol/24 h; P = 0.005) lower in the active arm than the control arm, whereas at 6 months the between-arms difference in UNa decreased and was no longer significant [23 mmol/24 h (95% CI −5.6–50.7); P = 0.11]. The 24-h ABPM changes as well as daytime and night-time BP changes at 3 and 6 months were similar in the two study arms (Month 3, P = 0.69–0.99; Month 6, P = 0.73–0.91). Office BP, the use of antihypertensive drugs, estimated Glomerular Filtration Rate (eGFR) and proteinuria remained unchanged across the trial. Conclusions The application of self-measurement of urinary chloride to guide adherence to a low salt diet had a modest effect on 24-h UNa and no significant effect on 24-h ABPM. [ABSTRACT FROM AUTHOR]

Lowering salt intake is a cornerstone strategy to optimize blood pressure (BP) control in chronic kidney disease (CKD) [1-2, 3], although recent studies have raised some concerns about the real benefit of a low salt diet on the renal prognosis in hypertensive and CKD patients [4-5, 6]. The averaged values of 24-h SBP, daytime BP, nighttime BP and office BP were 131 ± 16, 134 ± 15, 125 ± 18 and 152 ± 12 mmHg, respectively. [Extracted from the article]

Background: Excessive sodium intake is a risk factor for hypertension, cardiovascular disease and the risk for kidney failure in chronic kidney disease (CKD) patients. Methods: We tested the diagnostic performance and the feasibility of an inexpensive method based on urine chloride strips for self-monitoring sodium intake in a series of 72 CKD patients. Results: Twenty-four hour urinary chloride as measured by the reactive strips and 24 h urinary sodium were interrelated (r=0.59, p<0.001). Forty-nine out of 72 patients (78%) had a 24 h urinary sodium >100 mmol/24 h, i.e. the upper limit recommended by current CKD guidelines. The strip method had 75.5% sensitivity and 82.6% specificity to correctly classify patients with urine sodium >100 mmol/24 h. The positive and the negative predictive values were 90.2% and 61.3%, respectively. The overall accuracy (ROC curve analysis) of urine chloride self-measurement for the >100 mmol/24 h sodium threshold was 87% (95% CI: 77%–97%). The large majority of patients (97%) perceived the test as useful to help compliance with the prescribed dietary sodium and considered the test as simple and of immediate application (58%) or feasible but requiring attention (39%). Conclusions: A simple and inexpensive test for urine chloride measurement has a fairly good performance for the diagnosis of excessive sodium intake. The test is feasible and it is perceived by CKD patients as helpful for enhancing compliance to the dietary sodium recommendations. The usefulness of this test for improving hypertension control in CKD patients will be tested in a clinical trial (Clinicaltrials.gov RF-2010-2314890). [ABSTRACT FROM AUTHOR]

Background Thrombomodulin (TM) is a proteoglycan highly represented in the endothelial glycocalix that regulates the haemostasis and the endothelial response to inflammation. High soluble TM levels underlie a lower risk for coronary heart disease in population studies. Activation of vitamin D receptor (VDR) upregulates TM, but the effect of this intervention on soluble TM has never been tested in chronic kidney disease (CKD) patients. Methods We performed a post hoc analysis of a 12 weeks double blind, randomized, placebo-controlled trial testing the effect of VDR activation by paricalcitol (PCT) on endothelium-dependent flow - mediated vasodilatation (FMD) in the forearm (ClinicalTrials.gov identifier: NCT01680198). Circulating TM was measured in the whole CKD population [88 patients: PCT n  = 44; placebo n  = 44] that took part into this trial. Results Soluble TM at baseline was inversely related to the glomerular filtration rate (r  = −0.65, P < 0.001) and to FMD (Spearman's ρ = −0.29, P = 0.01). Alongside the expected effects on bone mineral biomarkers, PCT produced a consistent rise (P = 0.005) in TM levels, from a median value of 8446.0 pg/mL [interquartile range (IQR): 6227.8–10 910.8 pg/mL] to 9127.5 pg/mL (6393.0–11 287.3 pg/mL) while placebo had no effect (between-groups difference P = 0.008). TM levels re-approached baseline values 2 weeks after stopping PCT. TM changes across the trial paralleled simultaneous changes in FMD. Conclusions VDR activation by PCT raises TM levels and FMD and such effects are rapidly reversible after stopping the treatment. The TM rise induced by PCT is a possible mechanism whereby improvement in endothelial function by VDR activation may favourably impact upon vascular health in CKD patients. [ABSTRACT FROM AUTHOR]

Background The fibroblast growth factor 23 (FGF23) response to phosphate load is suppressed in adiponectin gene null mice and substantially amplified in mice overexpressing the same gene and vitamin D receptor (VDR) activation markedly enhances FGF23 gene expression. Methods We performed an analysis of the static (baseline adiponectin levels) and dynamic (fluctuations in adiponectin levels) interactions of serum adiponectin with the FGF23 response to paricalcitol and placebo in the setting of a double-blind, randomized clinical trial in chronic kidney disease (CKD) patients (NCT01680198). Results As compared with placebo, VDR activation by paricalcitol markedly increased serum FGF23 levels (P < 0.001), and such an increase was amplified in patients in the 4th adiponectin quartile as compared with other quartiles (P = 0.009) while no such an effect was noted in the placebo group (P = 0.49). Both baseline adiponectin (P for interaction = 0.009) and fluctuations in adiponectin levels following paricalcitol and placebo (P for interaction = 0.003) strongly modified the difference in the FGF23 response to these treatments. These interactions were specific because no similar effect modification by other factors with the FGF23 response to VDR activation was found. Furthermore, in a global correlation analysis, adiponectin and FGF23 were interrelated independent of the estimated glomerular filtration rate and other potential confounders (β = 0.22, P = 0.003). Conclusions Adiponectin is a strong modifier of the FGF23 response to VDR activation in CKD patients. The adiponectin–FGF23 link discovered in genetically engineered mice is of mechanistic relevance in the FGF23 response to VDR activation in CKD patients. [ABSTRACT FROM AUTHOR]

Background Neuropeptide Y (NPY) is a sympathetic neurotransmitter that has been implicated in various disorders including obesity, gastrointestinal and cardiovascular diseases. Methods We investigated the relationship between circulating NPY and the progression of the glomerular filtration rate (GFR) and proteinuria and the risk for a combined renal endpoint (>30% GFR loss, dialysis/transplantation) in two European chronic kidney disease (CKD) cohorts including follow-up of 753 and 576 patients for 36 and 57 months, respectively. Results Average plasma NPY was 104 ± 32 pmol/L in the first CKD cohort and 119 ± 41 pmol/L in the second one. In separate analyses of the two cohorts, NPY associated with the progression of the estimated GFR (eGFR) and proteinuria over time in both unadjusted and adjusted {eGFR: −3.60 mL/min/1.73 m2 [95% confidence interval (CI): −4.46 to − 2.74] P < 0.001 and −0.83 mL/min/1.73 m2 (−1.41 to − 0.25, P = 0.005); proteinuria: 0.18 g/24 h (0.11–0.25) P < 0.001 and 0.07 g/24 h (0.005–0.14) P = 0.033} analyses by the mixed linear model. Accordingly, in a combined analysis of the two cohorts accounting for the competitive risk of death (Fine and Gray model), NPY predicted (P = 0.005) the renal endpoint [sub-distribution hazard ratio (SHR): 1.09; 95% CI: 1.03–1.16; P = 0.005] and the SHR in the first cohort (1.14, 95% CI: 1.04–1.25) did not differ (P = 0.25) from that in the second cohort (1.06, 95% CI: 0.98–1.15). Conclusions NPY associates with proteinuria and faster CKD progression as well as with a higher risk of kidney failure. These findings suggest that the sympathetic system and/or properties intrinsic to the NPY molecule may play a role in CKD progression. [ABSTRACT FROM AUTHOR]

Background: Vitamin D associates with the plasma concentration of the endogenous inhibitor of the nitric oxide system asymmetric dimethyl arginine (ADMA) and cross-sectional studies in CKD patients treated with the vitamin D receptor activator paricalcitol show that plasma ADMA is substantially less than in those not receiving this drug. Methods: In the frame of a randomized, double-blind, placebo controlled trial, the Paracalcitol and ENdothelial fuNction in chronic kidneY disease (PENNY), we investigated whether vitamin D receptor activation by paricalcitol (2 μg/day x 12 weeks) affects the plasma concentration of ADMA and symmetric dimethyl arginine (SDMA) in 88 patients with stage 3 to 4 CKD. Results: Paricalcitol produced the expected small rise in serum calcium and phosphate and a marked PTH suppression. However, ADMA [Paricalcitol: baseline 0.75 μMol/L (95%CI: 0.70–0.81), 12 week 0.72 μMol/L (95%CI: 0.66–0.78); Placebo: baseline 0.75 μMol/L (95%CI: 0.70–0.90) 12 weeks 0.70 μMol/L (95%CI: 0.66–0.74)] and SDMA [Paricalcitol: baseline 0.91 μMol/L (95%CI: 0.82–1.00), 12 week 0.94 μMol/L (95%CI: 0.82–0.1.06); Placebo: baseline 0.91 μMol/L (95%CI: 0.82–1.06) 12 weeks 0.99 μMol/L (95%CI: 0.88–1.10)] remained unchanged during the trial and 2 weeks after stopping these treatments. Conclusions: Paricalcitol does not modify plasma ADMA and SDMA in patients with stage 3–4 CKD. The apparent beneficial effects of paricalcitol on ADMA registered in cross-sectional studies is likely attributable to confounding by indication rather than to a true effect of this drug on ADMA metabolism. [ABSTRACT FROM AUTHOR]

Context: Studies concerning the association between circulating resistin and mortality risk have reported, so far, conflicting results. Objective: To investigate the association between resistin and both all-cause and cardiovascular (CV) mortality risk by 1) analyzing data from the Gargano Heart Study (GHS) prospective design (n=359 patients; 81 and 58 all-cause and CV deaths, respectively); 2) performing meta-analyses of all published studies addressing the above mentioned associations. Data Source and Study Selection: MEDLINE and Web of Science search of studies reporting hazard ratios (HR) of circulating resistin for all-cause or CV mortality. Data Extraction: Performed independently by two investigators, using a standardized data extraction sheet. Data Synthesis: In GHS, adjusted HRs per one standard deviation (SD) increment in resistin concentration were 1.28 (95% CI: 1.07-1.54) and 1.32 (95% CI: 1.06-1.64) for all-cause and CV mortality, respectively. The meta-analyses included 7 studies (n=4016; 961 events) for all-cause mortality and 6 studies (n=4,187: 412 events) for CV mortality. Pooled HRs per one SD increment in resistin levels were 1.21 (95% CI: 1.03-1.42, Q-test p for heterogeneity<0.001) and 1.05 (95% CI: 1.01-1.10, Q-test p for heterogeneity=0.199) for all-cause and CV mortality, respectively. At meta-regression analyses, study mean age explained 9.9% of all-cause mortality studies heterogeneity. After adjusting for age, HR for all-cause mortality was 1.24 (95% CI: 1.06-1.45). Conclusions: Our results provide evidence for an association between circulating resistin and mortality risk among high-risk patients as are those with diabetes and coronary artery disease. [ABSTRACT FROM AUTHOR]

Altered vitamin D metabolism and low levels of the active form of this vitamin, 1,25-dihydroxy-vitamin D, is a hallmark of chronic kidney disease (CKD), but there is still no randomized controlled trial testing the effect of active forms of vitamin D on vascular function in patients with CKD. Paricalcitol and ENdothelial fuNction in chronic kidneY disease (PENNY) is a double-blinded randomized controlled trial (ClinicalTrials.gov, NCT01680198) testing the effect of an active form of vitamin D, paricalcitol (2 µg/dx 12 weeks) on endothelium-dependent and endothelium-independent vasodilatation in 88 patients with stage 3 to 4 CKD and parathormone >65 pg/mL (paricalcitol, n=44; placebo, n=44). Paricalcitol treatment reduced parathormone (-75 pg/mL; 95% confidence interval, -90 to -60), whereas parathormone showed a small rise during placebo (21 pg/mL; 95% confidence interval, 5-36). Blood pressure did not change in both study arms. Baseline flow-mediated dilation was identical in patients on paricalcitol (3.6±2.9%) and placebo (3.6±2.9%) groups. After 12 weeks of treatment, flow-mediated dilation rose in the paricalcitol but not in the placebo group, and the between- group difference in flow-mediated dilation changes (the primary end point, 1.8%; 95% confidence interval, 0.3-3.1%) was significant (P=0.016), and the mean proportional change in flow-mediated dilation was 61% higher in paricalcitol- treated patients than in placebo-treated patients. Such an effect was abolished 2 weeks after stopping the treatment. No effect of paricalcitol on endothelium-independent vasodilatation was registered. Paricalcitol improves endothelium-dependent vasodilatation in patients with stage 3 to 4 CKD. Findings in this study support the hypothesis that vitamin D may exert favorable effects on the cardiovascular system in patients with CKD. [ABSTRACT FROM AUTHOR]

Circulating urotensin (UTN) is increased in patients with heart failure and in patients with renal diseases, and UTN antagonism is currently considered as a potential treatment for these conditions. Contrary to this contention, studies in end-stage renal disease suggest that, perhaps because of interference with sympathetic and NO systems, UTN may be cardioprotective. Therefore, we investigated the relationship between circulating UTN and echocardiographic parameters of left ventricular function (midwall fractional shortening), left atrial volume, and myocardial geometry (mean wall thickness and relative wall thickness) in 191 patients with end-stage renal disease. UTN was associated directly (r=0.39; P<0.001) with left ventricular systolic function and inversely with left atrial volume (r=-0.40; P<0.001) and the muscular component of the left ventricular (UTN versus mean wall thickness: r=-0.30, P<0.001; UTN versus relative wall thickness: r=-0.32, P<0.001). Adjustment for a series of 11 risk factors produced a relatively small change in the strength of these relationships. However, further adjustment for plasma norepinephrine or, particularly so, for the endogenous inhibitor of NO synthase asymmetrical dimethyl arginine produced a 33% to 50% decrease in the strength of such associations. Of note, there was a strong UTN-asymmetrical dimethyl arginine interaction in determining midwall fractional shortening (P=0.001) and mean wall thickness (P=0.006). These data support the hypothesis that high UTN is cardioprotective in end-stage renal disease and that interference by UTN with sympathetic activity and NO synthesis represents an intermediate mechanism mediating the favorable echocardiographic profile of patients with high UTN. Additional mechanistic insights may be needed before launching long-term clinical trials with UTN antagonists in patients with end-stage renal disease. [ABSTRACT FROM AUTHOR]

Background: Urotensin II (UTN), a cyclic undecapeptide widely distributed in various organs and tissues, is found in high concentration in atheromatous lesions. Because UTN accumulates in patients with chronic renal failure, the association between plasma UTN and biomarkers of atherosclerosis and endothelial activation needs to be better understood. Methods: We tested by a robust statistical approach (Holm method) the association between plasma UTN and biomarkers of atherosclerosis and endothelial activation in a population of 191 patients undergoing chronic hemodialysis. Results: Plasma UTN was significantly higher in patients with end-stage renal disease (median: 6.5 ng/mL) than in healthy subjects (median: 3.1 ng/mL) (P < .001), and in both patients and control subjects it was independent of age and sex. Interestingly, UTN was inversely related to fibrinogen (r = −0.50, P < .004), intracellular adhesion molecule–1 (r = −0.24, P < .004) and with NO synthesis inhibitor asymmetric dimethyl-arginine (r = −0.40, P < .004). These links were paralleled by direct correlations with albumin (r = 0.21, P < .006) and with transforming growth factor–β1 (TGFβ1) (r = 0.36, P < .004). Of note, on multiple regression analysis, these associations remained highly significant also after data adjustment for potential confounders. Conclusions: The inverse links between UTN with biomarkers of atherosclerosis and endothelial activation suggest that downregulation of UTN may be a counter-regulatory response aimed at mitigating cardiovascular damage or that UTN itself is a protective factor. [Copyright &y& Elsevier]

Background: The parathyroid glands are endowed both with receptors responsive to FGF23 and to 1,25 vitamin D. Vitamin D receptor (VDR) activation, besides lowering PTH, also raises serum FGF23. FGF23 has been implicated in parathyroid resistance to VDR activation but the issue has never been investigated in predialysis CKD patients. Methods: In the Paricalcitol and Endothelial Functio in Chronic Kidney Disease (PENNY) study (NCT01680198), a 12‐week randomized trial in stage G3‐4 CKD patients (placebo n = 44 and paricalcitol n = 44), we measured PTH and the active form of FGF23 with no missing value across the trial. Results: At baseline, serum FGF23 and PTH were inter‐related (r =.54, P <.01). Paricalcitol reduced serum PTH (−75.1 pg/mL, 95% CI: −90.4 to −59.8; P <.001) and increased FGF23 (+107 pg/mL, 95% CI: 44‐170 pg/mL, P =.001). Changes in the Ca × P product in response to paricalcitol were closely related to simultaneous FGF23 changes in an analysis adjusted for changes in serum calcium and phosphate (P <.001). Of note, baseline FGF23, appropriately adjusted for baseline PTH, was unrelated with the PTH response to paricalcitol (r = −.06, P =.72). Placebo did not change neither PTH nor FGF23. Conclusion: Serum FGF23 and PTH are inter‐related and changes in the Ca × P product induced by paricalcitol per se correlate with the FGF23 response to this drug. Independently of serum FGF23, the parathyroid glands of patients with moderate to severe CKD maintain an intact ability to respond to VDR activation. [ABSTRACT FROM AUTHOR]

Erythroferrone (ERFE) is a hepcidin inhibitor whose synthesis is stimulated by erythropoietin, which increases iron absorption and mobilization. We studied the association between serum ERFE and mortality and non-fatal cardiovascular (CV) events in a cohort of 1123 hemodialysis patients and in a cohort of 745 stage 1–5 chronic kidney disease (CKD) patients. Erythroferrone was measured by a validated enzyme-linked immunosorbent assay (ELISA). In the hemodialysis cohort, serum ERFE associated directly with erythropoiesis stimulating agents (ESA) dose (p < 0.001) and inversely with serum iron and ferritin (p < 0.001). Erythroferrone associated with the combined outcome in an analysis adjusting for traditional risk factors, factors peculiar to end-stage kidney disease, serum ferritin, inflammation, and nutritional status (HR, hazard ratio, (5 ng/mL increase: 1.04, 95% confidence interval, CI: 1.01–1.08, p = 0.005). Furthermore, treatment with ESA modified the relationship between ERFE and the combined end-point in adjusted analyses (p for the effect modification = 0.018). Similarly, in CKD patients there was a linear increase in the risk for the same outcome in adjusted analyses (HR (2 ng/mL increase): 1.04, 95% CI: 1.0–1.07, p = 0.015). Serum ERFE is associated with mortality and CV events in CKD and in HD patients, and treatment by ESA amplifies the risk for this combined end-point in HD patients. [ABSTRACT FROM AUTHOR]

The soluble receptor of advanced glycation end product (sRAGE) prevents vascular damage in experimental animal models, and observational studies in the general population support the hypothesis that sRAGE may exert a protective role on the vasculature. To test this in patients with chronic kidney disease, we determined the relationship between plasma sRAGE and carotid atherosclerosis in 142 patients with an average estimated glomerular filtration rate (eGFR) of 32 ml/min per 1.73 m2 and 49 healthy control individuals matched for age and gender. Plasma sRAGE was significantly higher in patients with chronic kidney disease than in the control cohort. In an aggregate analysis of the patients and controls, there was a significant inverse relationship between eGFR and sRAGE, with a breakpoint in the regression line at 64 ml/min per 1.73 m2. Significant inverse relationships were found for sRAGE to intima–media thickness and plaque number in the patients with chronic kidney disease, but no such associations were found in the controls. On covariance analysis, the slopes of intima–media thickness and plaque number to sRAGE were significantly steeper in patients with chronic kidney disease than in the controls. Furthermore, a significant interaction was found between sRAGE and smoking for predicting atherosclerotic plaques in patients with chronic kidney disease. The pathophysiological significance of this correlation will have to await more mechanistic studies. [ABSTRACT FROM AUTHOR]

Vitamin D deficiency has been linked to cardiovascular disease and early mortality in patients on hemodialysis; however, it is not known if the same association exists at earlier stages of chronic kidney disease. To determine this we enrolled 168 consecutive new referrals to a chronic kidney disease clinic over a 2 year period and followed them for up to 6 years. All patients were clinically stable and had an estimated glomerular filtration rate (eGFR) at stage 2 or less and were without an imminent need for dialysis. Baseline 25-hydroxyvitamin D levels directly and significantly correlated with eGFR. After an average follow-up of 48 months, 48 patients started dialysis and 78 had died. In crude analyses, 25-hydroxyvitamin D predicted both time to death and end-stage renal disease. A dual-event Cox's model confirmed 25-hydroxyvitamin D as an independent predictor of study outcomes when adjusted for age, heart failure, smoking, C-reactive protein, albumin, phosphate, use of converting enzyme inhibitors or angiotensin receptor blockers, and eGFR. Our study shows that plasma 25-hydroxyvitamin D is an independent inverse predictor of disease progression and death in patients with stage 2–5 chronic kidney disease.Kidney International (2009) 75, 88–95; doi:10.1038/ki.2008.501; published online 8 October 2008 [ABSTRACT FROM AUTHOR]

Background: Adherence to low salt diets and control of hypertension remain unmet clinical needs in chronic kidney disease (CKD) patients., Methods: We performed a 6-month multicentre randomized trial in non-compliant patients with CKD followed in nephrology clinics testing the effect of self-measurement of urinary chloride (69 patients) as compared with standard care (69 patients) on two primary outcome measures, adherence to a low sodium (Na) diet (<100 mmol/day) as measured by 24-h urine Na (UNa) excretion and 24-h ambulatory blood pressure (ABPM) monitoring., Results: In the whole sample (N = 138), baseline UNa and 24-h ABPM were143 ± 64 mmol/24 h and 131 ± 18/72 ± 10 mmHg, respectively, and did not differ between the two study arms. Patients in the active arm of the trial used >80% of the chloride strips provided to them at the baseline visit and at follow-up visits. At the third month, UNa was 35 mmol/24 h (95% CI 10.8-58.8 mmol/24 h; P = 0.005) lower in the active arm than the control arm, whereas at 6 months the between-arms difference in UNa decreased and was no longer significant [23 mmol/24 h (95% CI -5.6-50.7); P = 0.11]. The 24-h ABPM changes as well as daytime and night-time BP changes at 3 and 6 months were similar in the two study arms (Month 3, P = 0.69-0.99; Month 6, P = 0.73-0.91). Office BP, the use of antihypertensive drugs, estimated Glomerular Filtration Rate (eGFR) and proteinuria remained unchanged across the trial., Conclusions: The application of self-measurement of urinary chloride to guide adherence to a low salt diet had a modest effect on 24-h UNa and no significant effect on 24-h ABPM., (© The Author(s) 2020. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.)

Introduction: The soluble receptor of urokinase plasminogen activator (suPAR) is an innate immunity/inflammation biomarker predicting cardiovascular (CV) and non-CV events in various conditions, including type 2 diabetic patients on dialysis. However, the relationship between suPAR and clinical outcomes in the hemodialysis population at large has not been tested., Methods: We measured plasma suPAR levels (R&D enzyme-linked immunosorbent assay [ELISA]) in 1038 hemodialysis patients with a follow-up of 2.9 years (interquartile range = 1.7-4.2) who were enrolled in the PROGREDIRE study, a cohort study involving 35 dialysis units in 2 regions in Southern Italy., Results: suPAR was strongly ( P  < 0.001) and independently related to female gender (β = -0.160), age (β = 0.216), dialysis vintage (β = 0.264), CV comorbidities (β = 0.105), alkaline phosphatase (β = 0.136), albumin (β = -0.147), and body mass index (BMI; β = 0.174) (all P  < 0.006). In fully adjusted analyses, suPAR tertiles predicted the risk of all-cause mortality (third tertile vs. first tertile hazard ratio (HR) = 1.91, 95% confidence interval (CI) = 1.47 - 2.48, P  < 0.001), CV mortality (HR = 1.47, 95% CI = 1.03-2.09, P  = 0.03), and non-CV mortality (HR = 1.94, 95% CI = 1.28-2.93, P  = 0.002); these relationships were not modified by diabetes or other risk factors. suPAR added only modest prognostic risk discrimination and reclassification power for these outcomes to parsimonious models based on simple clinical variables., Conclusion: In conclusion, suPAR robustly predicted all-cause and both CV and non-CV mortality in a large unselected hemodialysis population. Intervention studies are needed to definitively test the hypothesis that suPAR is causally implicated in clinical outcomes in this population.

Background and Objectives: The plasma concentration of the endogenous inhibitor of nitric oxide synthase asymmetric dimethylarginine (ADMA) associates with sympathetic activity in patients with CKD, but the driver of this association is unknown., Design, Setting, Participants, & Measurements: In this longitudinal study (follow-up: 2 weeks-6 months), repeated measurements over time of muscle sympathetic nerve activity corrected (MSNAC), plasma levels of ADMA and symmetric dimethylarginine (SDMA), and BP and heart rate were performed in 14 patients with drug-resistant hypertension who underwent bilateral renal denervation (enrolled in 2013 and followed-up until February 2014). Stability of ADMA, SDMA, BP, and MSNAC over time (6 months) was assessed in two historical control groups of patients maintained on stable antihypertensive treatment., Results: Time-integrated changes in MSNAC after renal denervation ranged from -40.6% to 10% (average, -15.1%), and these changes were strongly associated with the corresponding changes in plasma ADMA (r= 0.62, P=0.02) and SDMA (r=0.72, P=0.004). Changes in MSNAC went along with simultaneous changes in standardized systolic (r=0.65, P=0.01) and diastolic BP (r=0.61, P=0.02). In the historical control groups, no change in ADMA, SDMA, BP, and MSNAC levels was recorded during a 6-month follow-up., Conclusions: In patients with resistant hypertension, changes in sympathetic activity after renal denervation associate with simultaneous changes in plasma levels of the two major endogenous methylarginines, ADMA and SDMA. These observations are compatible with the hypothesis that the sympathetic nervous system exerts an important role in modulating circulating levels of ADMA and SDMA in this condition., (Copyright © 2015 by the American Society of Nephrology.)

Background and Objectives: High serum IL-6 is a major risk factor for cardiovascular disease (CVD) in the general population. This cytokine is substantially increased in patients with CKD, but it is still unknown whether the link between IL-6 and CVD in CKD is causal in nature., Design, Setting, Participants, & Measurements: In a cohort of 755 patients with stages 2-5 CKD, consecutively recruited from 22 nephrology units in southern Italy, this study assessed the relationship of serum IL-6 with history of CVD, as well as with incident cardiovascular (CV) events (mean follow up±SD, 31±10 months) and used the functional polymorphism (-174 G/C) in the promoter of the IL-6 gene to investigate whether the link between IL-6 and CV events is causal., Results: In adjusted analyses, serum IL-6 above the median value was associated with history of CVD (P<0.001) and predicted the incidence rate of CV events (hazard ratio, 1.66; 95% confidence interval [95% CI], 1.11 to 2.49; P=0.01). Patients homozygous for the risk allele (C) of the -174 G/C polymorphism had higher levels of IL-6 than did those with other genotypes (P=0.04). Homozygous CC patients more frequently had a history of CVD (odds ratio, 2.15; 95% CI, 1.15 to 4.00; P=0.02) as well as a 87% higher rate of incident CV events (hazard ratio, 1.87; 95% CI, 1.02 to 3.44; P=0.04) compared with other genotypes., Conclusions: In patients with stages 2-5 CKD, high serum IL-6 is associated with history of CVD and predicts incident CV events. The parallel relationship with history of CVD and incident CV events of the -174 G/C polymorphism in the IL-6 gene suggests that IL-6 may be causally involved in the high CV risk in this population., (Copyright © 2015 by the American Society of Nephrology.)

Objectives: Vascular endothelial growth factor induces nitric oxide-dependent angiogenic effects and participates in the inflammatory response. This cytokine is over-expressed in the myocardium in experimental models of pressure overload and renal mass ablation, and vascular endothelial growth factor is increased in end-stage renal disease. We investigated the relationship between vascular endothelial growth factor, left ventricular function (by midwall fractional shortening) and mortality in a prospective cohort study in 228 hemodialysis patients., Results: Serum vascular endothelial growth factor concentration was associated directly with interleukin-6 and tumor necrosis factor-alpha (P < 0.01) and inversely with albumin (P = 0.007) but was independent of the endogenous inhibitor of nitric oxide synthesis, asymmetric dimethylarginine. Vascular endothelial growth factor was inversely related with midwall fractional shortening (P = 0.002) and predicted mortality (P = 0.02). In multivariate analyses testing the involvement of this angiogenic cytokine in left ventricular dysfunction and death, these links remained substantially unmodified after adjustment for Framingham risk factors, risk factors peculiar to end-stage renal disease (Hb, Ca, P) and previous cardiovascular complications. However, these links became weaker and not significant when biomarkers of inflammation and asymmetric dimethylarginine were sequentially introduced into the multivariate models. In crude and adjusted analyses, left ventricular function was lowest in patients who displayed both high vascular endothelial growth factor and high asymmetric dimethylarginine, intermediate in patients with either high vascular endothelial growth factor or high asymmetric dimethylarginine and highest in those with low asymmetric dimethylarginine and low vascular endothelial growth factor (P = 0.001)., Conclusion: Vascular endothelial growth factor is associated with left ventricular systolic dysfunction and mortality in hemodialysis patients. Vascular endothelial growth factor appears to be in the pathway whereby inflammation and nitric oxide inhibition lead to cardiomyopathy and death in hemodialysis patients.

Background: Urotensin II (UTN) is a peptide highly conserved across species with disparate effects on the vascular system and it is currently unclear whether high plasma UTN levels play a vasculotoxic or a vasculoprotective role., Methods: In this study, we investigated the relationship between plasma UTN and sympathetic activity and cardiac natriuretic hormones in 191 hemodialysis (HD) patients without clinical evidence of heart failure., Results: Plasma UTN was significantly higher in patients with end-stage renal disease (ESRD) (median: 6.5 ng/mL) than in age matched healthy subjects (median: 3.1 ng/mL) (p<0.001). On univariate analysis, UTN was inversely related to heart rate (r=-0.24), dialysis treatment duration (r=-0.27), norepinephrine (r=-0.28), neuropeptide Y (NPY) (r=-0.66), brain natriuretic peptide (BNP) (r=-0.41) and atrial natriuretic peptide (ANP) (r=-0.28) (all p<0.008). Of note, in multiple regression analyses these associations maintained strength similar to that of the corresponding unadjusted correlation coefficients., Conclusions: The inverse links between UTN and neuro-hormonal factors indicate that UTN down-regulation in the presence of high sympathetic activity and high BNP could be a counter-regulatory response aimed at mitigating cardiovascular (CV) damage or that UTN itself acts as a protective factor.

Because inflammation influences thyroid function, it was hypothesized that low plasma free triiodothyronine (fT3) in ESRD may be an unsuspected expression of the inflammatory state of these patients. This study investigated (1) the steady-state relationship between fT3 and inflammation markers (IL-6 and C-reactive protein) and markers of endothelial activation (intercellular adhesion molecule-1 [ICAM-1] and vascular cellular adhesion molecule-1 [VCAM-1]) in 200 hemodialysis (HD) patients and (2) the effect of intercurrent acute inflammatory/infectious processes on plasma fT3 in a group of 17 patients with chronic kidney disease (CKD). HD patients displayed lower (P < 0.001) plasma fT3 than healthy subjects (n = 31) and clinically euthyroid patients with chronic diseases and normal renal function (n = 262). When HD patients were subdivided into IL-6 tertiles, fT3 was progressively lower across tertile increments (P < 0.001). Accordingly, regression analysis showed strong and inverse associations (P < or = 0.002) between fT3 and IL-6, C-reactive protein, ICAM-1, and VCAM-1, and, with the exception of the ICAM-fT3 relationship, these associations remained highly significant (P < or = 0.004) in multiple regression analyses adjusting for demographic variables, risk factors, and other potential confounders. In patients who had CKD and were studied during intercurrent inflammatory/infectious processes, fT3 was significantly lower (P = 0.008) at the zenith of inflammation than after its resolution. Low circulating fT3 is frequently observed in inflammatory illnesses, and the same association exists in patients with CKD and in ESRD. This association may entail a causal link because fT3 is acutely and reversibly suppressed in patients with CKD during inflammatory processes triggered by intercurrent infections.

Background and Objective: The adipose tissue cytokine leptin is suggested to interfere with bone turnover mechanisms because, in rats with leptin deficiency, intra-cerebroventricular administration of this cytokine causes a reduction in bone mass. We studied the relationship between plasma leptin and biochemical bone turnover indicators in 161 hemodialysis (HD) patients., Results: Plasma leptin was sex-dependent, being significantly higher (p<0.001 ) in female dialysis patients than in male dialysis patients, and it related directly to body mass index (BMI). In males, plasma leptin related inversely to serum intact parathyroid (PTH) (partial r= -0.34), serum PTH(1-84) (r= -0.36), carboxyterminal PTH (C-PTH) fragment (r= -0.31) and serum PTH(1-84)/C-PTH fragment ratio (r= -0.22), while no such relationships were found in females. Of 93 male dialysis patients, 44 had a serum intact PTH <100 pg/mL and 14 had a serum PTH(1-84)/C-PTH fragment ratio <1. In a multiple logistic regression analysis in males, for each 1 ng/mL increase in plasma leptin there was an 11% excess risk of serum intact PTH <100 pg/mL (odds ratio (OR) 1.11, 95% confidence interval (95% CI): 1.02-1.20, p=0.01) and a similar OR was found when low bone turnover was defined based on a serum PTH(1-84)/C-PTH fragment ratio <1 (p=0.01). In addition, plasma leptin related inversely to skeletal alkaline phosphatase and again this relationship was found in male but not in female dialysis patients., Conclusions: Our data support the theory that leptin reduces bone turnover in male dialysis patients. Whether this link underlies a noxious or a protective mechanism, i.e. if it can serve to limit high bone turnover due to hyperparathyroidism, remains to be established in prospective studies based on solid outcome measures like the risk of fractures.