Search

A study published in the American Journal of Nephrology suggests that inadequate sleep duration is linked to an increased risk of chronic kidney disease (CKD). The study, conducted on a large sample of mid-life and older Chinese adults, found that both short and long sleep duration were associated with a 44% increased risk of incident CKD. However, participants who reported consistent optimal sleep duration (7-9 hours) or supplemented short sleep with daytime napping had a reduced risk of developing CKD. The study also highlights the need for further research on the impact of sleep on kidney health, as well as the potential differences in sleep-related kidney health disparities among different racial and ethnic groups. [Extracted from the article]

Introduction: Chronic hypoxia is prevalent in chronic kidney disease (CKD), and blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) provides noninvasive evaluation of renal oxygenation. This study aimed to explore the correlation of renal oxygenation evaluated by BOLD-MRI with renal function. Methods: 97 non-dialysis patients with CKD stages 1–5 and healthy volunteers (HVs) were recruited in the study, all participants without diabetes. Based on their estimated glomerular filtration rate (eGFR), the patients were divided into two groups: CKD stages 1–3 (CKD 1–3) and CKD stages 4–5 (CKD 4–5). We measured cortical and medullary T2* (COT2* and MET2*) values in all participants by BOLD-MRI. Physiological indices were also recorded and compared among three groups. Correlation of T2* values with clinical characteristics was determined. Results: The COT2* values were significantly higher than MET2* values in all participants. The COT2* and MET2* values of three groups were ranked as HV > CKD 1–3> CKD 4–5 (p < 0.0001). There were positive correlations between the COT2* values, MET2* values and eGFR, hemoglobin (r > 0.4, p < 0.01). The 24-h urinary protein (24-h Upr) showed weak correlation with the COT2* value (rs = −0.2301, p = 0.0265) and no correlation with the MET2* value (p > 0.05). Urinary microprotein, including urinary alpha1-microglobulin, urinary beta2-microglobulin (β2-MG), and urinary retinol-binding protein (RBP), showed strong correlation with COT2* and MET2* values. According to the analysis of receiver operating characteristic curve, the optimal cut-points between HV and CKD 1–3 were "<61.17 ms" (sensitivity: 91.23%, specificity: 100%) for COT2* values and "<35.00 ms" (sensitivity: 77.19%, specificity: 100%) for MET2* values, whereas COT2* values ("<47.34 ms"; sensitivity: 90.00%, specificity: 92.98%) and MET2* values ("<25.09 ms"; sensitivity: 97.50%, specificity: 80.70%) between CKD 1–3 and CKD 4–5. Conclusion: The decline of renal oxygenation reflected on T2* values, especially in cortex, may be an effective diagnostic marker for early detection of CKD. [ABSTRACT FROM AUTHOR]

Background: Serum cystatin C (CysC) is still becoming used as a marker of renal function but is far from being commonly used worldwide. The purpose of this study was to characterize the ureteral calculi patients with hydronephrosis-caused CysC changes in renal function. Methods: To better reflect the changes of renal function, we constructed models of ureteral obstruction in rats to mimic the hydronephrosis caused by human ureteral calculi. Moreover, our study included 200 patients diagnosed with ureteral calculi in our hospital between June 2017 and 2018. We compared the estimated glomerular filtration rate using different equations based on CysC and/or serum creatinine (SCr). Results: We found that the expression of CysC and SCr increased with the prolonged obstruction time by enzyme linked immunosorbent assay. Moreover, quantitative real-time polymerase chain reaction, Western blot and immunohistochemistry further demonstrated that the expression of CysC increases with the degree of hydronephrosis. Among 200 patients with ureteral calculi, 40 (20.0%) had no hydronephrosis, 110 (55.0%) had mild hydronephrosis, 32 (16.0%) had moderate hydronephrosis and 18 (9.0%) had severe hydronephrosis. As the degree of hydronephrosis increased, the expression of neutrophil percentage, CysC, blood urea nitrogen, SCr and serum uric acid also increased. Multivariate analyses demonstrated that only CysC was an independent risk factor for hydronephrosis (p = 0.003). In addition, CysC and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) CysC equation showed the highest veracity in renal function estimation of patients with hydronephrosis caused by ureteral calculus. Conclusion: For patients with hydronephrosis caused by ureteral calculi, CysC better reflects the changes in renal function, and the CKD-EPI CysC equation has the highest accuracy. [ABSTRACT FROM AUTHOR]

Background: Treatment of metabolic acidosis to target the higher serum bicarbonate level than guideline recommendation may downregulate muscle protein degradation and improve renal function among chronic kidney disease (CKD) patients. We conducted a study to test the effects of increased serum bicarbonate level on muscle parameters, nutrition, and renal function in pre-dialysis CKD patients.Methods: This was a randomized, controlled study. CKD stage 3-4 patients with serum HCO3- <22 mEq/L were randomized to either receive oral sodium bicarbonate with high target bicarbonate level of 25 ± 1 or standard level of 22 ± 1 mEq/L as control group using protocol-based titration of dosage adjustment. The changes of muscle mass measured by bioelectrical impedance analysis (BIA), muscle strength by hand grip dynamometer, estimated glomerular filtration rate (eGFR) using CKD-Epidemiology Collaboration equation, nutritional markers, and muscle-related biomarkers were determined. Data at baseline and after 4 months of sodium bicarbonate supplementation were compared between groups using Student t test or chi-square test as appropriate.Results: Forty-two patients completed the study (n = 21 per group). The mean age and eGFR were 61.2 ± 9.8 years and 32.4 ± 14.1 mL/min respectively. Serum bicarbonate levels at baseline were 21.0 ± 2.1 mEq/L. Baseline data including sex, diabetes, serum bicarbonate level, creatinine, and blood pressure were similar. After 4 months of treatment, the average serum bicarbonate levels in both groups were 24.0 ± 1.4 and 20.7 ± 2.3 mEq/L (p < 0.001). Both BIA-derived total-body muscle mass and appendicular lean balance were increased at 4 months in the higher bicarbonate group (26.0 ± 5.3 to 26.7 ± 5.5 kg, p = 0.04 and 19.8 ± 4.1 to 20.7 ± 4.4 kg, p = 0.06, respectively) despite comparable body weight and protein intake. Patients in the high bicarbonate group had a significant reduction of plasma myostatin levels, a surrogate of muscle degradation, at the study exit after adjusting for baseline values (-3,137.8; 95% CI -6,235.3 to -40.4 pg/mL, p= 0.04), but unaltered insulin-like growth factor-1 level, as the mediator of muscle cell growth, (141 [106-156] to 110 [87-144] ng/mL, p = 0.13) compared to the control group. Muscle strength, eGFR as well as serum prealbumin were not significantly different between 2 groups (p > 0.05). Neither worsening hypertension nor congestive heart failure was found throughout the study.Conclusion: Bicarbonate supplementation to achieve the serum level ∼24 mEq/L demonstrates better muscle mass preservation in patients with pre-dialysis CKD. The impact of alkaline therapy on renal function may require a longer period of study. [ABSTRACT FROM AUTHOR]

Background: Metabolic acidosis (MA) is common in kidney transplant recipients (KTRs). Several studies have shown that MA is involved in the progression of chronic kidney disease. However, it is unclear if there is also a relationship between serum bicarbonate and graft function after kidney transplantation (KTx). We hypothesized that low serum bicarbonate is associated with a lower estimated glomerular filtration rate (eGFR) 1 year after KTx. Methods: We performed a post hoc analysis of a single-center, open-label randomized trial in 90 KTRs and investigated the relationship of serum bicarbonate and graft function in the first year after KTx. Results: Prevalence of MA was high after KTx (63%) and decreased to 28% after 1 year. Bicarbonate (20.6 ± 3.0 to 22.7 ± 2.7 mmol/L) increased in the first year after transplantation whereas eGFR (53.4 ± 15.8 to 56.9 ± 18.5 mL/min/1.73 m2) did not change significantly. Higher serum bicarbonate (p = 0.029) was associated with higher eGFR in the first year after KTx. Conclusion: Prevalence of MA is high in KTRs. In the first year after KTx, serum bicarbonate was positively correlated with eGFR, suggesting a potential role of MA in kidney graft function. [ABSTRACT FROM AUTHOR]

Background/Aims: Growth differentiation factor-15 (GDF-15) expression has been reported to increase in response to tissue damage and has recently emerged as a useful biomarker for various diseases. Although emerging evidence supports the clinicopathological value of GDF-15 in renal impairment, few studies have analyzed it in the elderly. Thus, we conducted a cross-sectional study to investigate the association of plasma GDF-15 with renal function and the presence of chronic kidney disease (CKD) in community-dwelling elderly. Materials: The present study was based on the baseline data of the Korean Frailty and Aging Cohort Study (KFACS), a nationwide cohort study that began in 2016. Of the 1,559 participants assessed in the first year, 443 with available plasma GDF-15 data were enrolled in this study. We investigated the association of plasma GDF-15 levels with clinical and biochemical parameters. The study population was divided into two groups according to renal function (CKD and non-CKD groups) to investigate whether GDF-15 can determine the presence of renal dysfunction in the elderly. Plasma GDF-15 was measured by enzyme-linked immunosorbent assay (ELISA) kit. Results: In a simple regression analysis, the levels of plasma GDF-15 were negatively correlated with estimated glomerular filtration rate (eGFR; r = –0.383, p < 0.001). In multiple linear regression analysis, GDF-15 levels were still significantly correlated with eGFR, even after adjusting for other parameters (r = –0.259, p < 0.001). Plasma GDF-15 levels were significantly higher in the elderly with CKD than in those without CKD (2,364.025 ± 1,052.23 ng/L and 1,451.23 ± 835.79 ng/L, respectively; p < 0.001). The optimal cut-off value of plasma GDF-15 for detecting the presence of CKD was 1,699.4 ng/L (76.5% sensitivity and 76.0% specificity), as determined by the receiver operating characteristic curve. The area under the curve was 0.793 ± 0.033 (95% CI 0.729–0.857, p < 0.001). Conclusion: Plasma GDF-15 levels were negatively associated with eGFR and were significantly increased in the elderly with CKD. Our results suggested that plasma GDF-15 might be a useful marker for discriminating renal impairment in the elderly. Further large and prospective outcome studies of extended duration are needed. [ABSTRACT FROM AUTHOR]

Background/Aims: The rate of incidence and prevalence of acute kidney injury is increasing due to an increased number of patients with heart failure. Therefore it is very pertinent to early detect the level of renal injuries and to make necessary heart failure predictions. Thus the aim of this study is to determine renal functions and prognosis stratification in chronic heart failure patients and importance of Neutrophil Gelatinase-Associated Lipocalin (NGAL), an early diagnostic marker of acute kidney injury, as well as stratification of cardiovascular risk in heart failure patients. Methods: Data including age, gender, comorbidities and medical history of outpatients and hospitalized patients from Farmacology and NeuroHumoraL activation (FAR NHL) multicenter prospective registry comprising three Cardiological Centers in the Czech Republic were collected between 1st October 2014 and 30th November 2015. One-year follow-up data were collected in November 2016 in such a way that all patients had at least one-year data from the time of recruitment, but up to two years to the time of follow-up. One-year data were used for the whole set of patients while data up to 24 months were used with Kaplan-Meier's survival curves to analyse the patients' survival data. Blood samples were collected from the patients and basic parameters were evaluated in order to analyse Neutrophil gelatinase-associated lipocalin (NGAL) and plasma levels of N-terminal pro-brain natriuretic peptide (NT-ProBNP) using Lipocalin-2/NGAL Human ELISA kit (Bio Vendor, Czechia) and the Cobas E411 NT-proBNP Immunoassay kit (Roche Diagnostics, Indianapolis, IN, USA) respectively. Statistical analysis was further carried out to explain the level of significance of the evaluated parameters using Spearman Correlation, Mann Whitney or Kruskal-Wallis test and log-rank test. Results: Out of 547 patients from Farmacology and NeuroHumoraL activation (FAR NHL) multicenter prospective registry with available data on hospitalizations, mortality, biomarkers and one-year follow-up that were recorded, there were 439 males (80.3%) with a median age of 66 years. At least one-month stable patients with left ventricle ejection fraction (LV EF) under 50% were recorded. The etiology of heart failure was ischemic heart disease in 54%, dilated cardiomyopathy in 40% and others in 6%. 69% patients were in New York Heart Association functional class II. There were 76 events (13.9%; all-cause mortality, acute heart failure hospitalization, left ventricle assist device implantation and orthotopic heart transplant) in the first 365 days of follow-up. The area under the receiver operating characteristic curve was higher for NT-proBNP (0.77) than the creatinine (0.57), NGAL (0.55) or creatinine clearance (0.54). In multivariable analyses, NT-proBNP (P= 0.001) and NGAL (P = 0.004) were significant predictors of events. Subjects with NT-proBNP and NGAL above the cut off value (NT-proBNP 1,121 pg/ml, NGAL 80 ng/ml) survived without any event in 55.7%, subjects with NT-proBNP and NGAL under the cut off value survived without any event in 90.5%, after two years (P = 0.001). Conclusion: The findings of the study showed that NGAL associated with NT-proBNP was a stronger predictor of the primary endpoint than NGAL or NT-proBNP alone. The level of NGAL was rising in hypertension, ischemia, anemia, hypoalbuminemia, diabetes or arrhythmias. [ABSTRACT FROM AUTHOR]

Background/Aims: Diabetic nephropathy is one of the main causes of end-stage renal disease. The present study investigated the effect of mononuclear cell (MC) therapy in rats subjected to diabetic nephropathy. Methods: Male Wistar rats were divided into control (CTRL), diabetic (DM), CTRL+MC and DM+MC groups. Diabetes was induced by a single injection of streptozotocin (45 mg/kg, i.p.) and, 4 weeks later, 2×107 MCs were injected via the jugular vein. Results: The rats in the DM and DM+MC groups showed increased glycemia, glomerular filtration rate and glomerular tuff area versus control groups. The glomerular filtration rate and glomerular tuff area were normalized in the DM+MC group. No alterations were observed in the fractional excretion of electrolytes and proteinuria between the DM and DM+MC groups. TGF-β1 protein levels in the DM group were significantly increased versus control animals and normalized in the DM+MC group. An increase in ED1+/arginase I+ macrophages and IL-10 renal expression was observed in the DM+MC group versus DM group. Conclusions: Bone marrow-derived MC therapy was able to prevent glomerular alterations and TGF-β1 protein overexpression and modulated glomerular arginase I+ macrophage infiltration in rats subjected to early diabetic nephropathy. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims: To test the hypothesis that Wilms tumour survivors (WTs) experience increased disturbance in renal function, even after prompt treatment, compared to patients with unilateral renal agenesis (URA). Methods: To assess the renal function of 30 WTs and 17 individuals with URA, the estimated glomerular filtration rate (eGFR) was calculated using the Schwartz and Filler formulas as well as the new Schwartz equation for chronic kidney disease. To measure kidney damage, serum levels and urine excretion of β2-microglobulin (B2M), cystatin C (Cys C), neutrophil gelatinase-associated lipocalin (NGAL) were tested, N-acetyl-β-glucosaminidase (NAG), and albumin urine excretion and urine sediment were examined. Blood pressure was measured. Results: No differences were found between the groups in terms of eGFR, serum Cys C, B2M and NGAL concentrations. The urine excretion of Cys C, NGAL and NAG was similar in both groups. URA patients had higher B2M excretion than WTs. Arterial hypertension was present in 7/30 (23%) WTs and 1/17 (6%) patients with URA. Conclusions: WTs have similar eGFR to individuals with URA and are more likely to have arterial hypertension. The patients with URA have signs of tubular damage. This study demonstrates the need for nephrological monitoring of individuals with a single kidney. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Obstructive sleep apnea (OSA) is associated with hypertension, obesity and metabolic syndrome that are risk factors for cardiovascular and chronic kidney disease. Few data are available regarding renal parameters in patients with OSA. Methods: We conducted a cross-sectional study of 91 obese adults who had routine polysomnography before bariatric surgery. Presence and severity of OSA were determined by the apnea-hypopnea index (AHI <5 = no OSA and AHI ≥5 = OSA). Clinical and laboratory data were available within a month of polysomnography. Results: Mean ± SD age was 44.9 ± 9.9 years. There were 66 women. Mean ± SD body mass index was 48.3 ± 8.9 kg/m2 with hypertension and type 2 diabetes present in 55 and 31 subjects, respectively. There were 36 subjects with no OSA and 55 with OSA. The two groups had similar demographic characteristics, blood pressure (BP), lipid profile and medication use except for difference in mean ± SD hemoglobin A1c (5.6 ± 0.6% in no OSA, 6.0 ± 0.8% in OSA; p = 0.029) and use of renin-angiotensin system blocking agents (22.2% in no OSA, 46.4% in OSA; p = 0.024). Median (interquartile range) urine albumin:creatinine ratio (ACR) was not different between the two groups [6 (4–14.5) mg/g in no OSA, 8 (5–16) mg/g in OSA; p = 0.723], while significant difference existed in serum creatinine (0.8 ± 0.2 mg/dl in no OSA, 0.9 ± 0.2 mg/dl in OSA, p = 0.013). Age- and gender-adjusted correlations were observed between log-log ACR and systolic BP (r = 0.265; p = 0.016), log-log ACR and diastolic BP (r = 0.245; p = 0.026) and between serum creatinine and log AHI (r = 0.188, p = 0.089). Multiple linear regression analysis demonstrated log-log ACR to be associated with diastolic BP (p = 0.046), while serum creatinine was associated with log AHI (p = 0.044). Conclusion: In obese adults, increasing severity of OSA is associated with higher serum creatinine but not greater degree of albuminuria. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/aims: Cardiovascular reactivity (CVR), defined as an exaggerated hemodynamic response to mental stress, is a putative vascular risk factor and may reflect sympathetic hyperactivity. Chronic kidney disease (CKD) is also associated with sympathetic hyperactivity and vascular risk, but its relationship with CVR is unknown.Methods: CVR was assessed in 107 individuals without overt cardiovascular disease or diabetes. Blood pressure and heart rate responses were elicited by three experimental tasks designed to evoke mental stress. Glomerular filtration rate (eGFR) was estimated using the MDRD formula. General linear models estimated the association between renal function and CVR, adjusting for potential confounders.Results: Mean age was 66 years and 11% had eGFR of <60 ml/min/1.73 m2. After multivariate adjustment, a low eGFR was associated with a greater stress response of systolic blood pressure, heart rate, and pulse pressure. Associations were only partially attenuated after adjustment for lipids and glucose tolerance. When considered as a continuous variable, lower eGFR was associated with a greater blood pressure response after adjustment for glycemia.Conclusion: Although there were relatively few participants with CKD, these results suggest a relationship between CKD and greater CVR. Further investigation is warranted into factors that mediate this relationship and potential clinical consequences of this exaggerated response to stress in CKD. [ABSTRACT FROM AUTHOR]

Objectives: The objectives of this study were: (1) to evaluate the specificity of cardiac troponin I and creatine kinase-MB isoenzyme in ambulatory asymptomatic chronic renal failure patients on long-term hemodialysis, and (2) to evaluate the effect of hemodialysis on the serum levels of cardiac troponin I and creatine kinase-MB isoenzyme. Methods: One hundred and forty-four consecutive ambulatory asymptomatic chronic renal failure patients on hemodialysis for a minimum of 1 year were evaluated clinically. Serum cardiac troponin I and creatine kinase-MB isoenzyme levels were measured with specific monoclonal antibodies before and after dialysis using ACCESS Troponin I and ACCESS CK-MB assays. Results: The specificity of serum cardiac troponin I was 83% with a cutoff level of 0.03 ng/ml, which is an expected level for healthy population, but it rose to 100% with a cutoff level of 0.15 ng/ml, which is a reference level for patients with acute myocardial infarction. Twenty-four (17%) patients had borderline elevation in cardiac troponin I (>0.03 to <0.15 ng/ml). A history of angina pectoris was more common in the borderline-elevated cardiac troponin I subgroup. In 28% of the patients, serum creatine kinase-MB isoenzyme levels were increased with a specificity of 72% at a cutoff level of 4 ng/ml, which is the upper limit of normal, but the specificity rose to 98% by increasing the cutoff level value to 10 ng/ml. There were no statistically significant differences in serum levels of cardiac troponin I and creatine kinase-MB isoenzyme before and after dialysis. Conclusions: Cardiac troponin I is highly specific in ambulatory asymptomatic chronic renal failure patients on long-term hemodialysis; borderline elevations in cardiac troponin I may represent microinjury to the myocardium. A serum level of creatine kinase-MB isoenzyme >2.5 times of the normal upper limit may be highly specific in this patient population. Hemodialysis per se does not significantly change the serum levels of cardiac troponin I and creatine kinase-MB isoenzyme. [ABSTRACT FROM AUTHOR]