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Background Glomerular filtration rate (GFR) is partially impaired in patients with multiple sclerosis (MS). When given chemotherapy before receiving hematopoietic stem-cell transplantation, GFR might be further deteriorated. Objective To measure the effect of cyclophosphamide on GFR in patients with MS who undergo chemotherapy. Methods We estimated GFR based on creatinine and cystatin C plasma concentrations in patients undergoing autologous hematopoietic stem-cell transplantation to treat their MS. Results Baseline GFR values were lower in the 28 patients with MS than in the 20 healthy individuals. Also, according to the Chronic Kidney Disease–Epidemiology Collaborative Group (CKD-EPI) 2012 Creat-CysC equation criteria, 4 of 28 patients were classified as having chronic kidney disease (CKD) before receiving the chemotherapy drugs. After receiving 4 × 50 mg per kg body weight cyclophosphamide, abnormal GFR results were recorded in 12 of 28 patients. Conclusions Renal function must be monitored in patients with MS undergoing autologous stem-cell transplantation. Also, chemotherapy should be constrained as much as possible to prevent further deterioration of renal function. [ABSTRACT FROM AUTHOR]

Aims The aim of this study was to examine urine creatinine concentrations in drivers submitted to controlled alcohol abstinence programs. Methods Urine samples (n = 32,210) were screened for ethyl glucuronide (EtG) by immunoassay during a 2-year period. Non-negatives underwent EtG and ethyl sulfate (EtS) confirmation by coupled-column Liquid Chromatography-Tandem Mass Spectrometry. Urine samples were tested for dilution by the analysis of creatinine content with <0.2 g/l indicating a dilute specimen. Results The mean urine creatinine was significantly higher in EtG positives compared to negatives (1.47 ± 0.98 vs. 1.17 ± 0.79 g/l). The difference between positives and negatives was consistent within genders and age groups (<45; ≥45). The higher urinary creatinine in EtG positives is explained by a late antidiuretic effect of alcohol. Conclusion Attempts to dilute urine specimens by drinking water or other liquids before voiding are less effective for EtG/EtS compared with illicit drugs excreted in urine. If the temporary decrease in serum creatinine as a consequence of the late antidiuretic effect of alcohol is confirmed by controlled studies, serum creatinine as an indicator of kidney function should be reconsidered in drinkers. [ABSTRACT FROM AUTHOR]

Background Renal function can be estimated with formulas, which are inaccurate, or measured with gold standard methods, which are reliable but unpractical. We propose to simplify the plasma clearance of iohexol, a gold standard method to measure renal function, by dried blood spot (DBS) testing. Methods We compared glomerular filtration rate (GFR) values assessed by DBS and the reference plasma analysis technique. We tested in vitro the agreement between non-volumetric and volumetric DBS with the reference technique. Then, we performed a clinical validation in vivo between volumetric DBS and plasma analysis in 203 patients. The agreement was evaluated with the concordance correlation coefficient (CCC), the total deviation index (TDI) and the coverage probability. We defined acceptable agreement as a TDI <10%. Results In the in vitro studies, the non-volumetric DBS showed moderate agreement, TDI = 26.0%, while the volumetric method showed better but insufficient agreement, TDI = 13.0%, with the reference method in plasma. The non-volumetric DBS was rejected. To improve the agreement of the volumetric DBS, iopamidol was used as an internal standard. This method showed acceptable agreement, TDI = 9.0% with the analysis in plasma, and was selected as the definitive DBS method. In the in vivo studies, the agreement between the final DBS method and the reference technique was acceptable: TDI = 9.5%. This indicates that 90% of the GFR values ranged from −9.5% to + 9.5% compared with the reference method. Conclusions We simplified the plasma clearance of iohexol using DBS without losing accuracy and precision with respect to the reference technique. This may facilitate the use of a reliable determination of renal function to the medical community. [ABSTRACT FROM AUTHOR]

Background: Serum osteoprotegerin (OPG) is elevated in patients with chronic kidney disease (CKD) and increases with decreasing renal function. However, there are limited data regarding the association between OPG and renal function in the general population. The aim of the present study was to explore the relation between serum OPG and renal function in subjects recruited from the general population. Methods: We conducted a cross-sectional study with 6689 participants recruited from the general population in Tromsø, Norway. Estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration equations. OPG was modelled both as a continuous and categorical variable. General linear models and linear regression with adjustment for possible confounderswere used to study the association between OPG and eGFR. Analyseswere stratified by the median age, as serum OPG and age displayed a significant interaction on eGFR. Results: In participants ≤62.2 years with normal renal function (eGFR ≥90 mL/min/1.73m2) eGFR increased by 0.35 mL/min/1.73m2 (95% CI 0.13-0.56) per 1 standard deviation (SD) increase in serum OPG after multiple adjustment. In participants older than the median age with impaired renal function (eGFR <90 mL/min/1.73m2), eGFR decreased by 1.54 (95% CI - 2.06 to - 1.01) per 1 SD increase in serum OPG. Conclusions: OPGwas associated with an increased eGFR in younger subjects with normal renal function and with a decreased eGFR in older subjects with reduced renal function. Our findings imply that the association between OPG and eGFR varies with age and renal function. [ABSTRACT FROM AUTHOR]

Proper control of the cell cycle is mandatory during homeostasis and disease. The balance of p53 and MDM2 integrates numerous signalling pathways to regulate the cell cycle, which is executed by multiple proteins including the cyclins, cyclin kinases and cyclin kinase inhibitors. Mutations or environmental factors that affect cell cycle control can lead to inappropriate hyperplasia or cancer as well as to cell loss and tissue atrophy. Normal kidney function is maintained largely by post-mitotic quiescent cells in the G0 phase with a low turnover. Early cell cycle activation during kidney injury contributes to cell death via mitotic catastrophe, i.e. death via mitosis, e.g. of cell with significant DNA damage. At later stages, cell cycle entry supports tissue regeneration and functional reconstitution via cell hypertrophy and/or cell proliferation. It is of note that so-called proliferation markers such as Ki67, PCNA or BrdU identify only cell cycle entry without telling whether this results in cell hypertrophy, cell division or mitotic catastrophe. With this in mind, some established concepts on kidney injury and regeneration are to be re-evaluated. Here, we discuss the components and functional roles of p53/MDM2-mediated cell cycle regulation in kidney homeostasis and disease. [ABSTRACT FROM AUTHOR]

Background: the impact of renal function and its changes and the occurrence of cardiovascular events on changes in N-terminal pro-brain natriuretic peptide levels (NT-proBNP) is unknown in very old age. Objective: to assess whether increase in NT-proBNP levels over time is still associated with cardiac disease and mortality in very old age, independent of renal function. Methods: changes in NT-proBNP levels between age 85 and 90 years and their associations with incident cardiac disease, (cardiovascular) mortality and renal function were assessed in 252 nonagenarian participants from a population-based sample of the Leiden 85-plus Study. Results: median NT-proBNP increase over 5 years was 154 pg/ml (inter-quartile range: 29-549), while in the same period estimated glomerular filtration rate (eGFR) decreased by 5.8 ml/min/1.73 m2 (standard deviation 7.5). Participants with increasing NT-proBNP levels more frequently developed heart failure and atrial fibrillation (odds ratio 2.79, 95% confidence interval (CI) 1.11-7.02 and 2.63, 95% CI 1.02-6.79, respectively, adjusted for eGFR at age 85 and change in eGFR) between age 85 and 90 years. Increasing NT-proBNP levels between age 85 and 90 years were associated with an increased cardiovascular mortality risk after age 90 years compared with not-increasing NT-proBNP levels (hazard ratio 1.62, 95% CI 1.04-2.51, adjusted for eGFR at age 90 years and change in eGFR). Conclusion: in the oldest old, increase in NT-proBNP is associated with incident heart failure and atrial fibrillation and risk for cardiovascular mortality, independent of decreasing renal function. [ABSTRACT FROM AUTHOR]

Background We investigate whether the urinary proteome refines the diagnosis of renal dysfunction, which affects over 10% of the adult population. Methods We measured serum creatinine, estimated glomerular filtration rate (eGFR) and 24-h albuminuria in 797 people randomly recruited from a population. We applied capillary electrophoresis coupled with mass spectrometry to measure multi-dimensional urinary proteomic classifiers developed for renal dysfunction (CKD273) or left ventricular dysfunction (HF1 and HF2). Renal function was followed up in 621 participants and the incidence of cardiovascular events in the whole study population. Results In multivariable-adjusted cross-sectional analyses, higher biomarker levels analysed separately or combined by principal component analysis into a single factor (SF), correlated (P ≤ 0.010) with worse renal function. Over 4.8 years, higher HF1 and SF predicted (P ≤ 0.014) lowering of eGFR; higher HF2 predicted (P ≤ 0.049) increase in serum creatinine and decrease eGFR. HF1, HF2 and SF predicted progression from CKD Stages 2 or ≤2 to Stage ≥3, with risk estimates for a 1-SD increment in the urinary biomarkers ranging from 38 to 71% (P ≤ 0.039). HF1, HF2 and SF yielded a net reclassification improvement of 31–51% (P ≤ 0.029). Over 6.1 years, 47 cardiovascular events occurred. HF2 and SF, independent of baseline eGFR, 24-h albuminuria and other covariables were significant predictors of cardiovascular complications with risk estimates for 1-SD increases ranging from 32 to 41% (P ≤ 0.047). Conclusions The urinary proteome refines the diagnosis of existing or progressing renal dysfunction and predicts cardiovascular complications. [ABSTRACT FROM AUTHOR]

Background Hyperuricemia is a risk factor for adverse renal outcomes in patients with chronic kidney disease. This study investigated the effect of uric acid on renal function in a community-based population. Methods We used a nationwide database of 165 847 subjects (aged 29–74, male 40%) who participated in the annual ‘Specific Health Check and Guidance in Japan’ checkup between 2008 and 2010; we examined the relationship between serum uric acid levels at baseline and 2-year change in the estimated glomerular filtration rate (eGFR) obtained by using the Japanese equation. Results After adjusting for possible confounders, the eGFR change was inversely correlated with uric acid at baseline. In the multivariable analysis, the decline in eGFR was significantly more rapid in subjects with the slight increase in uric acid (males ≥5.7 mg/dL, females ≥4.4 mg/dL), and the risk for incidental renal insufficiency (eGFR <60 mL/min/1.73 m2) was increased at uric acid of ≥6.3 mg/dL in males and ≥5.5 mg/dL in females, compared with the lowest quintile. The multiple linear regression analysis revealed that the effect of uric acid on eGFR changes was significant, especially in females, those with proteinuria and diabetes and those without alcohol consumption. Conclusion This study showed that serum uric acid is independently associated with a more rapid decline of eGFR and incident renal insufficiency, and that a slight increase within the normal range of serum uric acid might be a risk for renal damage in the general population. [ABSTRACT FROM AUTHOR]

Background: arterial stiffening is a marker of vascular ageing and an independent risk factor for cardiovascular disease. A potential mechanism linking cardiovascular disease to chronic kidney disease might be the change in arterial elasticity. We aim to determine the association between renal function and arterial stiffness in older subjects.Design: cross-sectional study.Setting: Rotterdam study, a population-based cohort study.Subjects: we included 3,279 subjects from 1997 to 1999 with a mean age of 71.9 years.Methods: estimation of glomerular filtration rate (eGFR) was used to assess renal function. Aortic pulse wave velocity (PWV) and carotid distensibility coefficient were used as measures of arterial stiffness.Results: each standard deviation increase in eGFR, adjusting for age and sex, was associated with 0.14 m/s lower PWV [95% confidence interval (CI): −0.23, −0.05]. Further adjustments for socio-demographic and cardiovascular risk factors did not change the association (β: −0.16 m/s; 95% CI: −0.26, −0.06). There was a linear association between mean values of PWV and quartiles of glomerular filtration rate (P for trend = 0.006). There was no association between decreased renal function and carotid distensibility. There was no statistical difference in the strength of the association between renal function and PWV in subgroups of participants with and without cardiovascular risk factors.Conclusions: in this large population-based study of elderly subjects, our findings suggest that renal impairment is associated with aortic stiffness. This association is independent of cardiovascular risk factors. [ABSTRACT FROM AUTHOR]

Background. Vitamin D deficiency is known as an important risk factor for mortality in patients with chronic kidney disease (CKD). Nevertheless, the association of renal function itself with vitamin D status or serum 25-hydroxyvitamin D (25OHD) level has not been investigated thoroughly. Methods. We examined the association between the estimated glomerular filtration rate (eGFR) and serum 25OHD levels using data from the 4th Korean National Health and Nutritional Examination Survey 2008. Generalized additive models (GAMs) were used to examine the relationship between eGFR and serum 25OHD levels and to estimate a threshold value of eGFR that predicts changes in serum 25OHD levels. Results. The mean serum 25OHD level was 20.4 ± 9.1 ng/mL, and the overall prevalence of vitamin D deficiency was 29.9% in this population. The prevalence of vitamin D deficiency began to increase at eGFR levels <45 mL/min/1.73m2. After adjustment, the logistic regression of dichotomized eGFR levels with a cut-point of 45 mL/min/1.73m2 yielded an increased odds ratio for vitamin D deficiency. Additionally, the continuous relationship between eGFR and 25OHD levels was explored using GAMs adjusted for various confounding factors. In this analysis, the difference from the mean serum 25OHD started to increase below an eGFR threshold of 55.4 mL/min/1.73m2, which suggests that renal function is directly related to the serum 25OHD levels in patients with CKD Stages 3–5. Conclusion. Although moderate renal dysfunction (eGFR < 45 mL/min/1.73m2) is an important predictor of vitamin D deficiency, serum 25OHD levels start to decrease below an eGFR level of ∼60 mL/min/1.73m2 independent of other risk factors. These results suggest that more careful attention to 25OHD levels may be needed when patients reach Stage 3 CKD. [ABSTRACT FROM PUBLISHER]

Background. Pneumocystis jiroveci pneumonia (PcP) is a potentially life-threatening complication in renal transplant recipients with increased reports during the past few years. Individual risk factors for susceptibility to PcP are incompletely understood.Methods. We retrospectively analysed 60 cases of confirmed PcP, diagnosed in six German transplant centres between 2004 and 2008, as well as 60 matched controls.Results. Compared with controls, PcP cases revealed the following significant differences: PcP cases had a poorer renal function (eGFR 31 vs. 42 mL/min in controls), more biopsy-proven rejections (18 vs. 5 patients), more frequent treatment with mycophenolate mofetil (53 vs. 44 patients) and less frequent treatment with interleukin-2 receptor antagonist (20 vs. 32 patients). According to centre policy, in those years, none of the patients or controls had received PcP prophylaxis after transplantation. Of the 60 patients with PcP, 30% developed the disease after the currently recommended duration of prophylactic treatment, 27% died in the course of the disease and 45% required treatment in the ICU.Conclusions. Our case–control study reveals a novel risk profile for PcP. Renal transplant recipients with more pronounced renal insufficiency following rejection episodes and treated with intensified immunosuppression are at particular risk for PcP. [ABSTRACT FROM AUTHOR]

Background. Impaired renal function has recently been reported in obstructive sleep apnoea (OSA). The underlying mechanisms, however, are not entirely understood. This study investigated the influence of mild-to-moderate OSA and its treatment on renal haemodynamics as assessed by the renal resistance index (RRI).Methods. RRI has been measured by colour duplex ultrasound in 64 patients with newly diagnosed mild-to-moderate OSA and 61 controls without OSA at baseline and follow-up after 9.9 months. Treatment with continuous positive airway pressure was offered to all patients with OSA (apnoea/hypopnoea index ≥ 5/h).Results. Increased values of RRI (≥ 1 SD [8.9%] above the age-adjusted normal value) were found in 41 out of 64 (64.0%) OSA patients when compared with 20 out of 61 (32.8%) controls (P < 0.001). The corresponding mean RRI was 70.50 ± 9.01 vs 66.51 ± 8.33 (P = 0.012). In multivariate analyses, the influence of OSA on RRI was independent from hypertension, diabetes mellitus, age and baseline renal function. At follow-up, RRI decreased only in patients with effective OSA treatment but remained unchanged in ineffectively treated OSA patients and controls.Conclusions. For the first time, this prospective controlled observational study demonstrates an impairment of renal haemodynamics in OSA as measured by an increased RRI. These changes of renal blood flow may identify OSA patients at high risk of declining renal function. Both parenchymal and vascular renal diseases are proposed as pathomechanisms for this association. An effective treatment of OSA resulted in a decreased RRI, suggesting an improvement in renal perfusion. Further studies are needed to elucidate the role of impaired renal haemodynamics in OSA. [ABSTRACT FROM AUTHOR]

Current guidance for evaluation of kidney function and drug dosing emphasize using measured or estimated glomerular filtration rate (GFR) rather than measured or estimated creatinine clearance or serum creatinine (Scr) alone. We assessed the definitions of kidney function thresholds for eligibility in cancer clinical trials. A random sample of active Phase I–III trials with cisplatin (n = 465) and studies in cancer with decreased kidney function (n = 74) were identified from clinicaltrials.gov. Among cisplatin trials, kidney function thresholds were defined by Scr alone or a composite of Scr or creatinine clearance in 46% (212/465) of studies. Only 2% (n = 11) used GFR. Among trials in participants with decreased kidney function, the proportion utilizing GFR (14%, 10/74) was modestly higher. Imprecise and logically inconsistent kidney function thresholds are in frequent use in clinical trials in cancer and may cause harm from either toxicity or impaired efficacy. We recommend the adoption and harmonization of recommended standards. [ABSTRACT FROM AUTHOR]