Different Relevance of Peripheral, Central or Nighttime Blood Pressure Measurements in the Prediction of Chronic Kidney Disease Progression in Patients with Mild or No-Proteinuria.

BACKGROUND/AIMS: Arterial hypertension is one of the leading factors aggravating the course of chronic kidney disease (CKD). It seems that the novel parameters used in the assessment of the blood pressure (BP) load (i.e. central blood pressure, nighttime blood pressure) may be more precise in predicting the cardiovascular risk and the progression of CKD in comparison with the traditional peripheral blood pressure measurements in the office conditions. The aim of the study was to assess the impact of the central, or nighttime blood pressure on the progression of CKD in patients with mild or no-proteinuria (autosomal, dominant polycystic kidney disease or IgA nephropathy). METHODS: In each of the enrolled 46 patients with CKD stage 3 or 4, serum creatinine concentration was assessed, eGFR (MDRD) was calculated, also central blood pressure and pulse wave velocity (PWV) was assessed and the 24-hour ambulatory blood pressure monitoring (ABPM) was conducted at the beginning of the study and then repeated after one-year observation period. RESULTS: During the observation period mean eGFR decreased from 44.1 (33.2-50.6) mL/min to 36.7 (29.7-46.3) mL/min. No significant differences were observed in the peripheral blood pressure or central blood pressure parameters. After one-year observation period the values of diastolic blood pressure dipping during the night significantly decreased from 16 (13-19) mmHg to 12 (10-15) mmHg; p< 0.05. The values of systolic dipping during the night or the mean BP values recorded in ABPM did not change significantly. Additionally, no significant differences in the PWV values were found. In the multivariate regression model the change of serum creatinine concentration was explained by the initial diastolic dipping values. CONCLUSION: 1. In patients with CKD stages 3 or 4 and mild or no- proteinuria, peripheral and central blood pressure did not change significantly during a one-year observation period despite the significant decline of eGFR and seems not to participate in the CKD progression. 2. Reduced magnitude of the diastolic dipping, which reflects the increase of diastolic blood pressure load during the nighttime, may play an important role in the pathogenesis of deterioration of kidney function in these patients.

Risk factors for progression of chronic kidney disease in the EPPIC trials and the effect of AST-120.

BACKGROUND: Two randomized, double-blind, placebo-controlled trials (EPPIC-1 and EPPIC-2) investigated the efficacy and safety of AST-120, an oral spherical carbon adsorbent, in adults with chronic kidney disease (CKD). While the benefit of adding AST-120 to standard therapy was not supported by these trials, we performed a post hoc analysis to focus on CKD progression and to determine the risk factors for the primary endpoint in the EPPIC trial population. METHODS: In the EPPIC trials, patients were randomly assigned 1:1 to treatment with AST-120 or placebo. The primary endpoint was a composite of dialysis initiation, kidney transplantation, or doubling of serum creatinine. The EPPIC trial pooled population was evaluated with the same statistical methods used for analysis of the primary and secondary efficacy endpoints. The trials were registered on ClinicalTrials.gov (NCT00500682 [EPPIC-1] and NCT00501046 [EPPIC-2]). RESULTS: An analysis of the placebo population suggested baseline urinary protein to urinary creatinine ratio (UP/UCr) ≥1.0 and hematuria were independent risk factors for event occurrence and eGFR lowering. Analysis of the high risk patients revealed a difference in the primary endpoint occurrence between treatment groups, if angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers were administered (hazard ratio 0.74, 95% confidence interval 0.56-0.96). Also, the eGFR changes from baseline in the AST-120 group were smaller than that in the placebo group (P = 0.035). CONCLUSIONS: CKD progression may have an association with baseline UP/UCr and hematuria. Treatment with AST-120 may delay the time to the primary endpoint in patients with progressive CKD receiving standard therapy, thus warranting further investigation.

Morbidity, mortality and quality of life in the ageing haemodialysis population: results from the ELDERLY study.

BACKGROUND: The physical-functional and social-emotional health as well as survival of the elderly (≥75 years of age) haemodialysis patient is commonly thought to be poor. In a prospective, multicentre, non-interventional, observational study, the morbidity, mortality and quality of life (QoL) in this patient group were examined and compared with a younger cohort. METHODS: In 92 German dialysis centres, 2507 prevalent patients 19-98 years of age on haemodialysis for a median of 19.2 months were included in a drug monitoring study of darbepoetin alfa. To examine outcome and QoL parameters, 24 months of follow-up data in the age cohorts <75 and ≥75 years were analysed. Treatment parameters, adverse and intercurrent events, hospitalizations, morbidity and mortality were assessed. QoL was evaluated by means of the 47-item Functional Assessment of Chronic Illness Therapy-Anaemia score (FACT-An, version 4). RESULTS: The 2-year mortality rate was 34.7% for the older cohort and 15.8% for the younger cohort. The mortality rate for the haemodialysed elderly patients was 6.2% higher in absolute value compared with the age-matched background population. A powerful predictor of survival was the baseline FACT-An score and a close correlation with the 20-item anaemia subscale (AnS) was demonstrated. While the social QoL in the elderly patients was more stable than in the younger cohort (leading to equivalent values at the end of the study period), a pronounced deterioration of physical and functional status was observed. The median number of all-cause hospital days per patient-year was 12.3 for the elderly cohort and 8.9 for the younger patient population. The overall 24-month hospitalization rate was only marginally higher in the elderly cohort (34.0 versus 33.3%). CONCLUSIONS: In this observational study, the mortality rate of elderly haemodialysis patients was not exceedingly high compared with the age-matched background population. Furthermore, the hospitalization rate was only slightly higher compared with the younger age group and the median yearly hospitalization time trended lower compared with registry data. The social well-being of elderly haemodialysis patients showed a less pronounced decline over time and was equal to the score of the younger cohort at the end of the study period. The physical and functional status in the elderly patients was lower and showed a sharper decline over time. The baseline FACT-An score correlated closely with the 24-month survival probability.

The effects of AST-120 on chronic kidney disease progression in the United States of America: a post hoc subgroup analysis of randomized controlled trials.

BACKGROUND: The orally administered spherical carbon adsorbent AST-120 is used on-label in Asian countries to slow renal disease progression in patients with progressive chronic kidney disease (CKD). Recently, two multinational, randomized, double-blind, placebo-controlled, phase 3 trials (Evaluating Prevention of Progression in Chronic Kidney Disease [EPPIC] trials) examined AST-120's efficacy in slowing CKD progression. This study assessed the efficacy of AST-120 in the subgroup of patients from the United States of America (USA) in the EPPIC trials. METHODS: In the EPPIC trials, 2035 patients with moderate to severe CKD were studied, of which 583 were from the USA. The patients were randomly assigned to two groups of equal size that were treated with AST-120 or placebo (9 g/day). The primary end point was a composite of dialysis initiation, kidney transplantation, or serum creatinine doubling. RESULTS: The Kaplan-Meier curve for the time to achieve the primary end point in the placebo-treated patients from the USA was similar to that projected before the study. The per protocol subgroup analysis of the population from the USA which included patients with compliance rates of ≥67 % revealed a significant difference between the treatment groups in the time to achieve the primary end point (Hazard Ratio, 0.74; 95 % Confidence Interval, 0.56-0.97). CONCLUSIONS: This post hoc subgroup analysis of EPPIC study data suggests that treatment with AST-120 might delay the time to primary end point in CKD patients from the USA. A further randomized controlled trial in progressive CKD patients in the USA is necessary to confirm the beneficial effect of adding AST-120 to standard therapy regimens. TRIAL REGISTRATION: ClinicalTrials.gov NCT00500682 ; NCT00501046 .

Effect of eplerenone on parathyroid hormone levels in patients with primary hyperparathyroidism: results from the EPATH randomized, placebo-controlled trial.

BACKGROUND: Accumulating evidence points toward mutual interaction between parathyroid hormone (PTH) and aldosterone as potential mechanism for increasing cardiovascular risk in primary hyperparathyroidism (pHPT). METHODS: The Eplerenone on parathyroid hormone levels in patients with primary hyperparathyroidism (EPATH) trial is a single-center, randomized, double-blind, parallel-group, placebo-controlled trial. The primary aim is to evaluate the effects of the mineralocorticoid receptor antagonist eplerenone on plasma intact PTH (iPTH) concentration in patients with pHPT. Secondary end points comprised surrogate parameters of cardiovascular health [24-h ambulatory SBP and DBP and echocardiographic parameters related to systolic/diastolic function as well as to cardiac dimensions]. RESULTS: We enrolled 110 study participants with pHPT, 25-hydroxyvitamin D at least 20 ng/ml and estimated glomerular filtration rate more than 50 ml/min per 1.73 m. Patients were 1 : 1 randomly assigned to receive either 25 mg eplerenone once daily (up-titration after 4 weeks to 50 mg/day) or matching placebo for a treatment period of 8 weeks.The study was completed by 97 participants [mean (SD) age: 67.5 ±â€Š9.5 years; 78.4% women). The mean treatment effect (95% confidence interval) for iPTH was 1.0 (0.9-1.1; P = 0.777) pg/ml. Mean 24-h ambulatory SBP and DBP decreased significantly [mean change (95% confidence interval) -6.3 (-9.4 to -3.3) and -3.7 (-5.7 to -1.7) mmHg, respectively; P < 0.001]. No differences were seen in any further secondary outcomes or frequency of adverse events. CONCLUSION: In pHPT, treatment with eplerenone compared with placebo had no effect on circulating iPTH levels. Eplerenone treatment was well tolerated and safe and followed by significant decrease of ambulatory blood pressure.

The Joint Society of Nephrology in Germany, Switzerland and Austria - Five Decades of Successful Activities.

The joint Society of Nephrology in Germany, Switzerland and Austria was founded on April 10th, 1961 in Wiesbaden. Board members were Hans Sarre, Kurt Kramer, Klaus Rother, Francois Reubi, Bruno Watschinger, Wolfgang Dutz, Ernst Wollheim and Karl Ullrich. The mission of the society was an intensive interaction between basic science of the kidney (anatomy, physiology, pathophysiology, biochemistry and molecular biology) and clinical research in nephrology and hypertension. Every year scientific symposia took place in different venues in one of the three countries, except in the years between 1963-1987, when the congresses of the International Society of Nephrology took place. Practical issues of clinical nephrology, in particular renal replacement therapy (dialysis and transplantation), were covered since 1971 by a specific Working Group. In 1994 the Advisory Board (Kuratorium) of the Society of Nephrology was founded as a result of an initiative of Peter Weidmann (Bern). Its main goals were Update Seminars in Nephrology and Hypertensionin Eastern Europe, in part together with the Joint Action of Nephrology and an Eastern European ScholarshipProgram. Despite the prosperous work of this European society within nearly five decades in Germany a national society was founded as well, which combined all activities of nephrology in one organization. The German Society of Nephrology was founded in 2009.

Lipoprotein(a) concentrations, apolipoprotein(a) isoforms and clinical endpoints in haemodialysis patients with type 2 diabetes mellitus: results from the 4D Study.

BACKGROUND: High lipoprotein(a) [Lp(a)] concentrations and low molecular weight (LMW) apolipoprotein(a) [apo(a)] isoforms are associated with cardiovascular disease and mortality in the general population. We examined the association of both with all-cause mortality and cardiovascular endpoints in haemodialysis patients with diabetes mellitus. METHODS: This is a post hoc analysis of the prospective 4D Study (German Diabetes Dialysis Study) that evaluated atorvastatin compared with placebo in 1255 haemodialysis patients with type 2 diabetes mellitus (median follow-up 4 years). The association of natural logarithm-transformed Lp(a) concentrations (increment one unit) and apo(a) isoforms with outcomes was analysed by Cox proportional hazards regression. The influence of age (median 66 years) was evaluated by stratified survival analyses. RESULTS: The median baseline Lp(a) concentration was 11.5 mg/dL (IQR 5.0-41.8). A quarter of patients had at least one LMW apo(a) isoform. Increased Lp(a) concentrations were associated with all-cause mortality in the total group [hazard ratio (HR) 1.09 (95% CI 1.03-1.16), P = 0.004]. LMW apo(a) isoforms were only associated with all-cause mortality in patients ≤ 66 years [HR 1.38 (95% CI 1.05-1.80), P = 0.02]. The strongest association for Lp(a) concentrations and LMW apo(a) isoforms was found for death due to infection in patients ≤ 66 years [HR 1.39 (95% CI 1.14-1.71), P = 0.001; HR 2.17 (95% CI 1.26-3.75), P = 0.005]. Lp(a) concentrations were also associated with fatal stroke in patients ≤66 years of age [HR 1.54 (95% CI 1.05-2.24), P = 0.03]. Neither Lp(a) nor LMW apo(a) isoforms were associated with other atherosclerosis-related events. CONCLUSIONS: High Lp(a) concentrations and LMW apo(a) isoforms are risk predictors for all-cause mortality and death due to infection in haemodialysis patients with diabetes mellitus. These associations are modified by age.

The double challenge of resistant hypertension and chronic kidney disease.

Resistant hypertension is defined as blood pressure above goal despite adherence to a combination of at least three optimally dosed antihypertensive medications, one of which is a diuretic. Chronic kidney disease is the most frequent of several patient factors or comorbidities associated with resistant hypertension. The prevalence of resistant hypertension is increased in patients with chronic kidney disease, while chronic kidney disease is associated with an impaired prognosis in patients with resistant hypertension. Recommended low-salt diet and triple antihypertensive drug regimens that include a diuretic, should be complemented by the sequential addition of other antihypertensive drugs. New therapeutic innovations for resistant hypertension, such as renal denervation and carotid barostimulation, are under investigation especially in patients with advanced chronic kidney disease. We discuss resistant hypertension in chronic kidney disease stages 3-5 (ie, patients with an estimated glomerular filtration rate below 60 mL/min per 1·73 m(2) and not on dialysis), in terms of worldwide epidemiology, outcomes, causes and pathophysiology, evidence-based treatment, and a call for action.

Administration of Cyclosporine A in Pregnant Rats - the Effect on Blood Pressure and on the Glomerular Number in Their Offspring.

BACKGROUND/AIMS: Cyclosporine A (CsA) is a commonly used immunosuppressive agent. In some patients treatment with CsA has to be continued during pregnancy. The aim of the study was to assess in an experimental model whether the exposure to CsA during fetal life influences the number and volume of glomeruli, kidney function and blood pressure in the offspring. METHODS: Eight pregnant female Sprague-Dawley rats were allocated to 2 treatment regimens: with CsA or solvent. Blood pressure was measured in the offspring at 7 and 11 weeks of age and albuminuria was determined at 11 weeks of age. In the kidney the number and mean volume of glomeruli was assessed using stereological methods. RESULTS: In the offspring of pregnant rats treated with CsA the number of glomeruli was significantly lower and the mean volume of glomeruli was higher when compared to the offspring of pregnant rats receiving solvent. Systolic and diastolic blood pressures as well as albuminuria were significantly higher in the offspring of mothers treated with CsA during gestation compared to the offspring from the control group. CONCLUSIONS: Exposure of rats to CsA during fetal life impairs kidney development, thus potentially predisposing to chronic kidney disease and hypertension in the adult life.

Association of relative telomere length with progression of chronic kidney disease in two cohorts: effect modification by smoking and diabetes.

Chronic kidney disease (CKD) is a highly progressive disease. We studied the association between relative telomere length (RTL) and CKD progression and tested whether this association is modified by smoking and diabetes mellitus. RTL was measured by qPCR in two prospective cohort studies, the MMKD-Study (n = 166) and the CRISIS-Study (n = 889) with a median follow-up of 4.5 and 2.8 years, respectively. Progression was defined as doubling of baseline serum creatinine (MMKD-Study) and/or end stage renal disease (both studies). 59 and 105 of the patients from MMKD and CRISIS experienced a progression of CKD. Mean standardized pooled RTL was 0.74 ± 0.29. In the meta-analysis shorter RTL at baseline showed a borderline association with CKD progression (HR = 1.07 [95%CI 1.00-1.15]; p = 0.06). We observed an effect modification of RTL and CKD progression by smoking and diabetes (p-values of interaction p = 0.02 and p = 0.09, respectively). Each 0.1 unit shorter RTL was significantly associated with an increased hazard for CKD progression in active-smokers by 44% (HR = 1.44 [1.16-1.81]; p = 0.001) and in patients with diabetes mellitus by 16% (HR = 1.16 [1.01-1.34]; p = 0.03). Estimates were adjusted for baseline age, sex, proteinuria and GFR. This study in two independent cohorts reinforces that RTL is a marker and potentially a pathogenetic factor for CKD progression.

Intestinal cholesterol absorption, treatment with atorvastatin, and cardiovascular risk in hemodialysis patients.

BACKGROUND: Hemodialysis patients are high absorbers of intestinal cholesterol; they benefit less than other patient groups from statin therapy, which inhibits cholesterol synthesis. OBJECTIVES: This study sought to investigate whether the individual cholesterol absorption rate affects atorvastatin's effectiveness to reduce cardiovascular risk in hemodialysis patients. METHODS: This post-hoc analysis included 1,030 participants in the German Diabetes and Dialysis Study (4D) who were randomized to either 20 mg of atorvastatin (n=519) or placebo (n=511). The primary endpoint was a composite of major cardiovascular events. Secondary endpoints included all-cause mortality and all cardiac events. Tertiles of the cholestanol-to-cholesterol ratio, which is an established biomarker of cholesterol absorption, were used to identify high and low cholesterol absorbers. RESULTS: A total of 454 primary endpoints occurred. On multivariate time-to-event analyses, the interaction term between tertiles and treatment with atorvastatin was significantly associated with the risk of reaching the primary endpoint. Stratified analysis by cholestanol-to-cholesterol ratio tertiles confirmed this effect modification: atorvastatin reduced the risk of reaching the primary endpoint in the first tertile (hazard ratio [HR]: 0.72; p=0.049), but not the second (HR: 0.79; p=0.225) or third tertiles (HR: 1.21; p=0.287). Atorvastatin consistently significantly reduced all-cause mortality and the risk of all cardiac events in only the first tertile. CONCLUSIONS: Intestinal cholesterol absorption, as reflected by cholestanol-to-cholesterol ratios, predicts the effectiveness of atorvastatin to reduce cardiovascular risk in hemodialysis patients. Those with low cholesterol absorption appear to benefit from treatment with atorvastatin, whereas those with high absorption do not benefit.

Uric Acid and Cardiovascular Events: A Mendelian Randomization Study.

Obesity and diets rich in uric acid-raising components appear to account for the increased prevalence of hyperuricemia in Westernized populations. Prevalence rates of hypertension, diabetes mellitus, CKD, and cardiovascular disease are also increasing. We used Mendelian randomization to examine whether uric acid is an independent and causal cardiovascular risk factor. Serum uric acid was measured in 3315 patients of the Ludwigshafen Risk and Cardiovascular Health Study. We calculated a weighted genetic risk score (GRS) for uric acid concentration based on eight uric acid-regulating single nucleotide polymorphisms. Causal odds ratios and causal hazard ratios (HRs) were calculated using a two-stage regression estimate with the GRS as the instrumental variable to examine associations with cardiometabolic phenotypes (cross-sectional) and mortality (prospectively) by logistic regression and Cox regression, respectively. Our GRS was not consistently associated with any biochemical marker except for uric acid, arguing against pleiotropy. Uric acid was associated with a range of prevalent diseases, including coronary artery disease. Uric acid and the GRS were both associated with cardiovascular death and sudden cardiac death. In a multivariate model adjusted for factors including medication, causal HRs corresponding to each 1-mg/dl increase in genetically predicted uric acid concentration were significant for cardiovascular death (HR, 1.77; 95% confidence interval, 1.12 to 2.81) and sudden cardiac death (HR, 2.41; 95% confidence interval, 1.16 to 5.00). These results suggest that high uric acid is causally related to adverse cardiovascular outcomes, especially sudden cardiac death.

Interrelated aldosterone and parathyroid hormone mutually modify cardiovascular mortality risk.

BACKGROUND: Inappropriate aldosterone and parathyroid hormone (PTH) secretion is associated with increased cardiovascular risk. Accumulating evidence suggests bidirectional interplay between aldosterone and PTH. METHODS: We evaluated the cross-sectional relationship between plasma aldosterone concentration (PAC), aldosterone to renin ratio (ARR) and PTH and subsequently tested whether the interaction between PAC and PTH modified the risk of cardiovascular death. PAC [78.0 (48.0-123.0) pg/mL], ARR [6.4 (2.9-12.9) pg/mL/pg/mL] and PTH concentration [median: 29.0 (22.0-40.0) pg/mL] were measured in 3074 patients (mean age: 62.5 ± 10.6 years; 30.3% women) referred to coronary angiography in a tertiary care center in Southwest Germany. RESULTS: Using multiple linear regression analysis, PAC and ARR emerged as an independent predictor of higher PTH concentrations (ß=0.12 and 0.21, P<0.001 for both) irrespective of intake of antihypertensive treatment, 25(OH)D, kidney function, serum calcium, phosphate, magnesium, cortisol, NT-pro-BNP, soluble α-klotho and FGF-23 concentration. After a median follow-up of 9.9 years, 512 (16.7%) participants had died due to fatal cardiovascular events. Multivariate Cox proportional hazard analysis revealed that both PAC and PTH were independently associated with cardiovascular mortality, with a potential synergistic interaction (P=0.028). PAC and PTH are exclusively associated with cardiovascular death in subjects with PTH and PAC concentrations above the median, respectively (PAC: HR per log SD: 1.14; 95% CI 1.02-1.29; P=0.026; PTH: HR per log SD: 1.18; 95% CI 1.02-1.37; P=0.031). CONCLUSIONS: Higher PAC and ARR were independently associated with PTH. PAC was independently related to incident cardiovascular mortality exclusively in patients with elevated PTH and vice versa.

Homoarginine in patients with primary hyperparathyroidism.

BACKGROUND: Low levels of the amino acid homoarginine and parathyroid hormone (PTH) excess are both independently related to an increased risk of cardiovascular morbidity and mortality. Accumulating evidence points to a mutual interplay between homoarginine and PTH. The authors therefore aimed to investigate circulating homoarginine levels in patients with and without primary hyperparathyroidism (PHPT). METHODS: The authors performed a cross-sectional analysis of serum homoarginine levels in 59 patients with mild and severe PHPT and in 92 control persons matched for age, sex and estimated glomerular filtration rate. RESULTS: Median PTH and serum homoarginine concentrations were 99.1 (79.7-120.2) pg/mL and 1.16 (0.95-1.66) µmol/L in patients with PHPT (79.7% female; 42.4% with normocalcemia) as compared with 45.8 (36.4-53.9) pg/mL and 1.62 (1.33-2.04) µmol/L in the control group (P < 0.001 for both), respectively. The authors observed no statistically differences between cases and controls for 25-hydroxyvitamin D [25(OH)D], serum albumin, hemoglobin, waist-to-hip ratio, C-reactive protein and NT-pBNP values. Multivariate analysis of covariance revealed that patients with PHPT had significantly lower homoarginine levels than controls (P < 0.001). This difference remained significant after adjusting for multiple confounders such as 25(OH)D, body mass index, LDL cholesterol, albumin, calcium, hemoglobin, smoking status and current antihypertensive medication. The differences of homoarginine levels persisted even after exclusion of patients with estimated glomerular filtration rate <60 mL/min (P = 0.003) and 25(OH)D levels <30 ng/mL (P = 0.001), respectively. CONCLUSIONS: Patients with PHPT have lower homoarginine levels compared with matched controls irrespective of age, sex, kidney function and 25(OH)D status. Further studies are needed to evaluate whether low homoarginine accounts for higher cardiovascular risk conferred by PTH excess.

Galectin-3, Renal Function, and Clinical Outcomes: Results from the LURIC and 4D Studies.

Galectin-3 has been linked to incident renal disease, experimental renal fibrosis, and nephropathy. However, the association among galectin-3, renal function, and adverse outcomes has not been described. We studied this association in two large cohorts of patients over a broad range of renal function. We measured galectin-3 concentrations in baseline samples from the German Diabetes mellitus Dialysis (4D) study (1168 dialysis patients with type 2 diabetes mellitus) and the Ludwigshafen Risk and Cardiovascular Health (LURIC) study (2579 patients with coronary angiograms). Patients were stratified into three groups: eGFR of ≥90 ml/min per 1.73 m(2), 60-89 ml/min per 1.73 m(2), and <60 ml/min per 1.73 m(2). We correlated galectin-3 concentrations with demographic, clinical, and biochemical parameters. The association of galectin-3 with clinical end points was assessed by Cox proportional hazards regression within 10 years (LURIC) or 4 years (4D) of follow-up. Mean±SD galectin-3 concentrations were 12.8±4.0 ng/ml (eGFR≥90 ml/min per 1.73 m(2)), 15.6±5.4 ng/ml (eGFR 60-89 ml/min per 1.73 m(2)), 23.1±9.9 ng/ml (eGFR<60 ml/min per 1.73 m(2)), and 54.1±19.6 ng/ml (dialysis patients of the 4D study). Galectin-3 concentration was significantly associated with clinical end points in participants with impaired kidney function, but not in participants with normal kidney function. Per SD increase in log-transformed galectin-3 concentration, the risks of all-cause mortality, cardiovascular mortality, and fatal infection increased significantly. In dialysis patients, galectin-3 was associated with the combined end point of cardiovascular events. In conclusion, galectin-3 concentrations increased with progressive renal impairment and independently associated with cardiovascular end points, infections, and all-cause death in patients with impaired renal function.

Phosphate: are we squandering a scarce commodity?

Phosphorus is an essential element for life but is a rare element in the universe. On Earth, it occurs mostly in the form of phosphates that are widespread but predominantly at very low concentration. This relative rarity has resulted in a survival advantage, in evolutionary terms, to organisms that conserve phosphate. When phosphate is made available in excess it becomes a cause for disease, perhaps best recognized as a potential cardiovascular and renal risk factor. As a reaction to the emerging public health issue caused by phosphate additives to food items, there have been calls for a public education programme and regulation to bring about a reduction of phosphate additives to food. During the Paleoproterzoic era, an increase in the bioavailability of phosphate is thought to have contributed significantly to the oxygenation of our atmosphere and a dramatic increase in the evolution of new species. Currently, phosphate is used poorly and often wasted with phosphate fertilizers washing this scarce commodity into water bodies causing eutrophication and algal blooms. Ironically, this is leading to the extinction of hundreds of species. The unchecked exploitation of phosphate rock, which is an increasingly rare natural resource, and our dependence on it for agriculture may lead to a strange situation in which phosphate might become a commodity to be fought over whilst at the same time, health and environmental experts are likely to recommend reductions in its use.

Marinobufagenin in essential hypertension and primary aldosteronism: a cardiotonic steroid with clinical and diagnostic implications.

BACKGROUND: The cardiotonic steroid marinobufagenin (MBG) is increasingly suggested to be responsible for some of the cardiovascular injury that has been previously attributed to aldosterone. We examined the clinical correlates of circulating MBG concentrations in hypertensive patients and tested the hypothesis that MBG serves as a reliable diagnostic tool for detecting primary aldosteronism (PA). METHODS: Plasma MBG concentrations (mean: 0.51±0.25 nmol/l) were measured in the morning fasting samples in 20 patients with PA and 20 essential hypertensive (EH) controls matched for age, sex, body mass index, renal function, urinary sodium and intake of antihypertensive medication (mean age: 51.6 years; 52.2% women). RESULTS: Overall, plasma MBG was directly correlated with plasma aldosterone, aldosterone to active renin ratio (AARR), diastolic blood pressure, mean carotid intima-media thickness, serum sodium, urinary protein to creatinine ratio and inversely with serum potassium levels. Plasma MBG levels were significantly higher in patients with PA compared to EH (mean: 0.68±0.12 versus 0.35±0.24 nmol/l; p<0.001). ROC analysis yielded a greater AUC for plasma MBG compared to the AARR, PAC and serum potassium levels for detecting PA. Youden's Index analyses yielded the optimal plasma MBG cut-off score for diagnosing PA at >0.49 nmol/l with specificity and sensitivity values of 0.85 and 0.95, respectively, which were higher than those at the optimum AARR cut-off at >3.32 ng/dl/µU/ml. CONCLUSIONS: In a well-characterized cohort, values of plasma MBG were significantly related to clinical correlates of cardiovascular and renal disease. Plasma MBG emerged as a valuable alternative to the AARR for screening of PA.

HDL cholesterol, apolipoproteins, and cardiovascular risk in hemodialysis patients.

High concentrations of HDL cholesterol are considered to indicate efficient reverse cholesterol transport and to protect from atherosclerosis. However, HDL has been suggested to be dysfunctional in ESRD. Hence, our main objective was to investigate the effect of HDL cholesterol on outcomes in maintenance hemodialysis patients with diabetes. Moreover, we investigated the associations between the major protein components of HDL (apoA1, apoA2, and apoC3) and end points. We performed an exploratory, post hoc analysis with 1255 participants (677 men and 578 women) of the German Diabetes Dialysis study. The mean age was 66.3 years and the mean body mass index was 28.0 kg/m(2). The primary end point was a composite of cardiac death, myocardial infarction, and stroke. The secondary end point included all-cause mortality. The mean duration of follow-up was 3.9 years. A total of 31.3% of the study participants reached the primary end point and 49.1% died from any cause. HDL cholesterol and apoA1 and apoC3 quartiles were not related to end points. However, there was a trend toward an inverse association between apoA2 and all-cause mortality. The hazard ratio for death from any cause in the fourth quartile compared with the first quartile of apoA2 was 0.63 (95% confidence interval, 0.40 to 0.89). The lack of an association between HDL cholesterol and cardiovascular risk may support the concept of dysfunctional HDL in hemodialysis. The possible beneficial effect of apoA2 on survival requires confirmation in future studies.

Randomized Placebo-Controlled EPPIC Trials of AST-120 in CKD.

Reduced GFR in patients with CKD causes systemic accumulation of uremic toxins, which has been correlated with disease progression and increased morbidity. The orally administered spherical carbon adsorbent AST-120 reduces systemic toxin absorption through gastrointestinal sequestration, which may slow disease progression in these patients. The multinational, randomized, double-blind, placebo-controlled Evaluating Prevention of Progression in CKD (EPPIC)-1 and EPPIC-2 trials evaluated the effects of AST-120 on the progression of CKD when added to standard therapy. We randomly assigned 2035 adults with moderate to severe disease (serum creatinine at screening, 2.0-5.0 mg/dl for men and 1.5-5.0 mg/dl for women) to receive either placebo or AST-120 (9 g/d). The primary end point was a composite of dialysis initiation, kidney transplantation, and serum creatinine doubling. Each trial continued until accrual of 291 primary end points. The time to primary end point was similar between the AST-120 and the placebo groups in both trials (EPPIC-1: hazard ratio, 1.03; 95% confidence interval, 0.84 to 1.27; P=0.78) (EPPIC-2: hazard ratio, 0.91; 95% confidence interval, 0.74 to 1.12; P=0.37); a pooled analysis of both trials showed similar results. The estimated median time to primary end points for the placebo groups was 124 weeks for power calculations, but actual times were 189.0 and 170.3 weeks for EPPIC-1 and EPPIC-2, respectively. Thus, disease progression was more gradual than expected in the trial populations. In conclusion, the benefit of adding AST-120 to standard therapy in patients with moderate to severe CKD is not supported by these data.

Impact of aldosterone on osteoinductive signaling and vascular calcification.

Vascular calcification is frequently found already in early stages of chronic kidney disease (CKD) patients and is associated with high cardiovascular risk. The process of vascular calcification is not considered a passive phenomenon but involves, at least in part, phenotypical transformation of vascular smooth muscle cells (VSMCs). Following exposure to excessive extracellular phosphate concentrations, VSMCs undergo a reprogramming into osteo-/chondroblast-like cells. Such 'vascular osteoinduction' is characterized by expression of osteogenic transcription factors and triggered by increased phosphate concentrations. A key role in this process is assigned to cellular phosphate transporters, most notably the type III sodium-dependent phosphate transporter Pit1. Pit1 expression is stimulated by mineralocorticoid receptor activation. Therefore, aldosterone participates in the phenotypical transformation of VSMCs. In preclinical models, aldosterone antagonism reduces vascular osteoinduction. Patients with CKD suffer from hyperphosphatemia predisposing to vascular osteogenic transformation, potentially further fostered by concomitant hyperaldosteronism. Clearly, additional research is required to define the role of aldosterone in the regulation of osteogenic signaling and the consecutive vascular calcification in CKD, but more generally also other diseases associated with excessive vascular calcification and even in individuals without overt disease.