Electrolyte Imbalance in Anti-LGI1 Encephalitis: It Is Not All in Your Head.

BACKGROUND AND OBJECTIVES: Antileucine-rich glioma-inactivated 1 (anti-LGI1) autoimmune encephalitis was first described in 2010 and is today the most common type of limbic encephalitis. During the course of the disease, 60%-88% of the patients develop hyponatremia. The etiology of the sodium disorder is unclear, often presumed to be the result of the syndrome of inappropriate antidiuretic hormone secretion (SIADH). Other electrolyte abnormalities have not been reported in association with anti-LGI1 antibody encephalitis. Due to the presence of hypomagnesemia and hypophosphatemia in our patients, we set out to try to find the expression of LGI1 protein in the kidney as an explanation for these abnormalities. METHODS: We reviewed the medical files of all patients diagnosed with anti-LGI1 antibody encephalitis, at the Department of Neurology in the Tel Aviv Medical Center between January 2011 and December 2020, exploring for electrolyte abnormalities. Using tissue staining, Western blot, mass spectrometry, and RNA expression techniques, we tried to demonstrate the expression of LGI1 protein in the human kidney. RESULTS: We identified 15 patients diagnosed with anti-LGI1 antibody encephalitis. Their average age was 65 years (44-80), and 9 were male individuals. Thirteen of the 15 patients (87%) developed varying degrees of hyponatremia. Laboratory studies demonstrated low serum osmolality, low serum blood urea nitrogen, and low uric acid, with a high urinary sodium and inappropriately high urine osmolality, supporting the presumable diagnosis of SIADH. One patient with hyponatremia that was tested, had high levels of copeptin, supporting the diagnosis of SIADH. In addition to hyponatremia, 7 patients (47%) exhibited other electrolyte abnormalities; 5 patients (33%) had overt hypophosphatemia, 4 patients (27%) had overt hypomagnesemia, and 2 other patients (13%) had borderline low magnesium levels. Western blot analysis of human kidney lysate, mass spectrometry, and qRT-PCR failed to demonstrate the expression of LGI1 protein in the kidney. DISCUSSION: Hyponatremia in patients with anti-LGI1 antibody encephalitis is due to SIADH as previously assumed. Other electrolyte abnormalities such as hypomagnesemia and hypophosphatemia occur in at least 40% of patients and may be another clue for the diagnosis of anti-LGI1 antibody encephalitis. Because we failed to demonstrate LGI1 expression in the kidney, the results of our study suggest that renal losses lead to these disturbances, most probably due to SIADH.

Renal Tubular CD24 Upregulation Aggravates Folic Acid Induced Acute Kidney Injury: A Possible Role for T Regulatory Cells Inhibition in Mice.

Acute kidney injury (AKI) is characterized by cell death and inflammation. CD24 is a protein induced during tissue damage and is not expressed in mature renal tissue. We explored the role of CD24 in the pathogenesis of folic acid-induced AKI (FA-AKI) in mice. A single Intraperitoneal (IP) injection of folic acid induced AKI in WT and CD24-/- mice. Renal function tests, histological analysis, immunohistochemistry, Western blot analysis, and ELISA were performed to assess the severity of renal damage and the intensity of the inflammatory response. FA-AKI induced CD24 in the distal tubular epithelial cells. Compared to WT mice, FA-AKI CD24-/- mice exhibited an attenuated reduction in renal function and histological injury, lower serum IL-10 and interferon γ, and decreased expression of renal TNFα. In contrast, renal and systemic IL-33 upregulation were augmented. CD24-/- FA-AKI animals exhibited increased splenic margination and renal infiltration of regulatory T cells (Tregs). At day 7, FA-AKI CD24-/- mice exhibited increased expression of tubular pro-apoptotic and decreased anti-apoptotic proteins compared to WT animals. Anti-CD24 antibody administration to FA-AKI mice attenuated the decrease in renal function as well as the histological injury. Renal biopsies from patients with ATN stained strongly for CD24 in the distal tubules. In conclusion, during AKI, upregulation of CD24 promotes renal inflammation through inhibition of Treg infiltration and diversion of cell death towards necrosis rather than apoptosis. Neutralization of CD24 may prove a target for future therapies in AKI.

The Prognostic Value of Anti-PLA2R Antibodies Levels in Primary Membranous Nephropathy.

Anti-PLA2R antibodies (Ab) are a diagnostic and prognostic biomarker in primary membranous nephropathy (PMN). We assessed the relationship between the levels of anti-PLA2R Ab at diagnosis and different variables related to disease activity and prognosis in a western population of PMN patients. Forty-one patients with positive anti-PLA2R Ab from three nephrology departments in Israel were enrolled. Clinical and laboratory data were collected at diagnosis and after one year of follow-up, including serum anti-PLA2R Ab levels (ELISA) and glomerular PLA2R deposits on biopsy. Univariable statistical analysis and permutation-based ANOVA and ANCOVA tests were performed. The median [(interquartile range (IQR)) age of the patients was 63 [50-71], with 28 (68%) males. At the time of diagnosis, 38 (93%) of the patients had nephrotic range proteinuria, and 19 (46%) had heavy proteinuria (≥8 gr/24 h). The median [IQR] level of anti-PLA2R at diagnosis was 78 [35-183] RU/mL. Anti-PLA2R levels at diagnosis were correlated with 24 h proteinuria, hypoalbuminemia and remission after one year (p = 0.017, p = 0.003 and p = 0.034, respectively). The correlations for 24 h proteinuria and hypoalbuminemia remained significant after adjustment for immunosuppressive treatment (p = 0.003 and p = 0.034, respectively). Higher levels of anti-PLA2R Ab at diagnosis in patients with active PMN from a western population are associated with higher proteinuria, lower serum albumin and remission one year after the diagnosis. This finding supports the prognostic value of anti-PLA2R Ab levels and their possible use in stratifying PMN patients.

Energy Harvesting by Mesoporous Reduced Graphene Oxide Enhanced the Mediator-Free Glucose-Powered Enzymatic Biofuel Cell for Biomedical Applications.

Harnessing electrochemical energy in an engineered electrical circuit from biochemical substrates in the human body using biofuel cells is gaining increasing research attention in the current decade due to the wide range of biomedical possibilities it creates for electronic devices. In this report, we describe and characterize the construction of just such an enzymatic biofuel cell (EBFC). It is simple, mediator-free, and glucose-powered, employing only biocompatible materials. A novel feature is the two-dimensional mesoporous thermally reduced graphene oxide (rGO) host electrode. An additionally novelty is that we explored the potential of using biocompatible, low-cost filter paper (FP) instead of carbon paper, a conductive polymer, or gold as support for the host electrode. Using glucose (C6H12O6) and molecular oxygen (O2) as the power-generating fuel, the cell consists of a pair of bioelectrodes incorporating immobilized enzymes, the bioanode modified by rGO-glucose oxidase (GOx/rGO), and the biocathode modified by rGO-laccase (Lac/rGO). Scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), transmission electron microscopy, and Raman spectroscopy techniques have been employed to investigate the surface morphology, defects, and chemical structure of rGO, GOx/rGO, and Lac/rGO. N2 sorption, SEM/EDX, and powder X-ray diffraction revealed a high Brunauer-Emmett-Teller surface area (179 m2 g-1) mesoporous rGO structure with the high C/O ratio of 80:1 as well. Results from the Fourier transform infrared spectroscopy, UV-visible spectroscopy, and electrochemical impedance spectroscopy studies indicated that GOx remained in its native biochemical functional form upon being embedded onto the rGO matrix. Cyclic voltammetry studies showed that the presence of mesoporous rGO greatly enhanced the direct electrochemistry and electrocatalytic properties of the GOx/rGO and Lac/rGO nanocomposites. The electron transfer rate constant between GOx and rGO was estimated to be 2.14 s-1. The fabricated EBFC (GOx/rGO/FP-Lac/rGO/FP) using a single GOx/rGO/FP bioanode and a single Lac/rGO/FP biocathode provides a maximum power density (Pmax) of 4.0 nW cm-2 with an open-circuit voltage (VOC) of 0.04 V and remains stable for more than 15 days with a power output of ∼9.0 nW cm-2 at a pH of 7.4 under ambient conditions.

Obesity-Related Glomerulopathy: Clinical Management.

Obesity-related glomerulopathy (ORG) and other obesity-associated kidney diseases pose a major challenge to the treating nephrologist. We review the benefits of weight loss and optimal management of ORG and kidney disease in the setting of obesity. Therapeutic strategies in ORG were limited mainly in the past to weight loss through lifestyle interventions and bariatric surgery, antihypertensive treatment, and renin-angiotensin-aldosterone system blockade. Current approaches to obtain the desired weight loss include novel pharmacologic therapies that have been approved for the treatment of diabetes while offering kidney protection, such as sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1-receptor agonists. This review focuses on the nephroprotective role of the renin-angiotensin-aldosterone system blockade and of these new pharmacologic agents, and on the renal effects of bariatric surgery in chronic kidney disease.

International Society of Nephrology Global Kidney Health Atlas: structures, organization, and services for the management of kidney failure in Western Europe.

Populations in the high-income countries of Western Europe are aging due to increased life expectancy. As the prevalence of diabetes and obesity has increased, so has the burden of kidney failure. To determine the global capacity for kidney replacement therapy and conservative kidney management, the International Society of Nephrology conducted multinational, cross-sectional surveys and published the findings in the International Society of Nephrology Global Kidney Health Atlas. In the second iteration of the International Society of Nephrology Global Kidney Health Atlas, we aimed to describe the availability, accessibility, quality, and affordability of kidney failure care in Western Europe. Among the 29 countries in Western Europe, 21 (72.4%) responded, representing 99% of the region's population. The burden of kidney failure prevalence varied widely, ranging from 760 per million population (pmp) in Iceland to 1612 pmp in Portugal. Coverage of kidney replacement therapy from public funding was nearly universal, with the exceptions of Germany and Liechtenstein where part of the costs was covered by mandatory insurance. Fourteen (67%) of 21 countries charged no fees at the point of care delivery, but in 5 countries (24%), patients do pay some out-of-pocket costs. Long-term dialysis services (both hemodialysis and peritoneal dialysis) were available in all countries in the region, and kidney transplantation services were available in 19 (90%) countries. The incidence of kidney transplantation varied widely between countries from 12 pmp in Luxembourg to 70.45 pmp in Spain. Conservative kidney care was available in 18 (90%) of 21 countries. The median number of nephrologists was 22.9 pmp (range: 9.47-55.75 pmp). These data highlight the uniform capacity of Western Europe to provide kidney failure care, but also the scope for improvement in disease prevention and management, as exemplified by the variability in disease burden and transplantation rates.

Status of Nutrition in Hemodialysis Patients Survey (SNIPS): Nutrition Intake in Obese and Overweight vs. Healthy Weight Patients.

Elevated body mass index (BMI) has been associated with improved survival and fewer hospitalizations in hemodialysis patients; however, it is not clear that dietary intake is associated with increased BMI in hemodialysis patients. The present analysis was designed to compare energy and macronutrient intake and distribution, as well as compliance with the International Society of Renal Nutrition and Metabolism (ISRNM) dietary guidelines, by body weight status (overweight/obese vs. normal weight) in hemodialysis patients. The status of nutrition in hemodialysis patients survey (SNIPS) cohort is a cross-sectional study including a representative sample of individuals on hemodialysis treated in hospital dialysis centers throughout Israel. Of the 375 patients eligible for the current analysis, 60.1% had BMI ≥ 25 kg/m2 (overweight/obese). For each participant, the following measures were recorded: dietary intake, blood biochemistry, anthropometric and hemodynamic measures. These were compared by body weight status. Compared to their normal-weight counterparts, overweight/obese hemodialysis patients did not differ by energy and macronutrient intake, distribution of these nutrients in the diet. Regardless of body weight status, hemodialysis patients have poor compliance with ISRNM dietary guidelines.

Status of Nutrition In Hemodialysis Patients Survey (SNIPS): Malnutrition risk by diabetes status.

BACKGROUND: Increased malnutrition risk has been observed in more than 40% people on haemodialysis in Israel. It is not clear that this risk is homogeneously distributed among people with versus without diabetes. OBJECTIVES: To examine the influence of diabetes on malnutrition risk among people on haemodialysis. METHODS: This cross-sectional study included a representative sample of 375 individuals on haemodialysis treated in hospital dialysis centres throughout Israel. Of these, 126 had diabetes. Dietary intake, biochemistry, anthropometric and hemodynamic measures were recorded. Malnutrition risk categories were defined: "minimal": body mass index (BMI) ≥23 kg/m2 and serum albumin ≥38 mmol/L; "mild": BMI <23 kg/m2 and albumin ≥38 mmol/L; "moderate": BMI ≥23 kg/m2 and albumin <38 mmol/L; "severe": BMI<23 k/m2 and serum albumin <38 mmol/L. These categories were dichotomized to "minimal" versus elevated malnutrition risk. RESULTS: Despite greater BMI, elevated malnutrition risk was identified in 58.8% of individuals with versus 39.3% without diabetes. Adherence to International Society for Renal Nutrition and Metabolism nutrition guidelines was poor regardless of diabetes status. In multivariable logistic regression analysis, diabetes: OR 2.15; C-reactive protein (nmol/L): OR 1.02; delivered dialysis dose (Kt/V): OR 6.07; and haemoglobin (g/L): OR 0.79, predicted elevated malnutrition risk, even after controlling for age, sex and years on haemodialysis. DISCUSSION: Individuals on haemodialysis who have diabetes have elevated malnutrition risk compared to those without diabetes despite greater BMI.

The European Certificate in Nephrology: towards harmonization and excellence in training.

Nephrology is a young medical specialty that has evolved and expanded during the last 4 decades of the past century, becoming recognized as one of the most innovative and challenging medical specialties. The training of nephrology takes place mainly in public hospitals, and there are important variations in the duration and assessment of training among the European countries. The Union of European Medical Specialties (UEMS) Renal Section and the European Renal Association-European Dialysis and Transplant Association have been working jointly since 2010 to harmonize European nephrology training and more recently to establish the European Certificate in Nephrology (ECN). The first two editions of the ECN were held in early 2017 and 2018. In total, 122 candidates from 26 countries have sat for the exam, with a success rate of 59% (72/122). To date, Switzerland has adopted the exam as their national training assessment and we expect that other countries will join Switzerland in the near future. Fostering the development and importance of the ECN requires that member states work to increase the academic and professional profile of the ECN within their countries. The ECN should be considered a 'quality mark' and a sign of high achievement in nephrology training in Europe. If holding the ECN becomes advantageous for employment or improving scientific careers, the number of candidates will increase and the sustainability of the ECN will be guaranteed. A recent, positive development is the pre-agreement between the UEMS Renal Section, UK Renal Association and Royal Colleges of the UK to adopt a unique pan-European exam beginning in 2020. However, any decision to commence the pan-European exam will depend, in part, on strong candidate enrolment for the ECN 2019 edition. Thus support of the national societies is crucial for the sustainability and growth of a European exam, because of their capacities to influence strategic policies in hospitals, universities and medical associations, with a longer-term aim to increase the professional recognition of the European exam.

Long term metabolic and renal outcomes of kidney donors compared to controls with excellent kidney function.

BACKGROUND: Only few studies of living kidney donors have included controls that were similarly healthy, including excellent kidney function. METHODS: In this study, we aimed to estimate long term metabolic and renal outcome in a cohort of 211 living donors compared to two control groups: paired-matched controls, and another control group of 2534 healthy individuals with excellent kidney function. RESULTS: Donors presented with higher estimated Glomerular Filtration Rate (eGFR): (97.6 ± 15.2 vs 96.1 ± 12.2 vs 94.5 ± 12.4 ml/min/1.73m2) and lower urine albumin to creatinine ratio (UACR) (4.3 ± 5.9 vs 5.9 ± 6.1 vs 6.1 ± 6.9 mg/g) for donors, matched controls and healthy controls, respectively (p <  0.001). In a mean follow up period of 5.5 for donors, donors presented with positive eGFR slopes during the first 3 years post donation, followed by negative slopes, compared to constantly negative slopes presented in the control group (p <  0.05). The variables related to the slope were being a donor, baseline eGFR, Body Mass Index (BMI) and age but not eGFR on the last day of follow-up or increased delta UACR. There was a significant increase in UACR in donors, as well as a higher rate of albuminuria, associated with a longer time since donation, higher pre-donation UACR and higher pre-donation BMI. Healthy controls had a lower BMI at baseline and gained less weight during the follow up period. Donors and controls had similar incidence of new onset diabetes mellitus and hypertension, as well as similar delta systolic and diastolic blood pressure. Donors were more likely to develop new onset metabolic syndrome, even after adjustment for age, gender and BMI. The higher incidence of metabolic syndrome resulted mainly from increased triglycerides and impaired fasting glucose criteria. However, prevalence of major cardiovascular events was not higher in this group. CONCLUSIONS: Donors are at increased risk to develop features of the metabolic syndrome in addition to the expected mild reduction of GFR and increased urine albumin excretion. Future studies are needed to explore whether addressing those issues will impact post donation morbidity and mortality.

Profound Decrease in Glomerular Arginine Transport by CAT (Cationic Amino Acid Transporter)-1 Contributes to the FLT-1 (FMS-Like Tyrosine Kinase 1) Induced Preeclampsia in the Pregnant Mice.

Endothelial dysfunction because of nitric oxide inactivation has been suggested to play a role in the pathogenesis of preeclampsia. During pregnancy, L-arginine transport by CAT-1 (cationic amino acid transporter 1), the only transporter for eNOS (endothelial nitric oxide synthase) is inhibited. We hypothesize that maternal arginine deficiency contributes to the development of preeclampsia. Adenovirus-mediated overexpression of sFlt-1 (soluble fms-like tyrosine kinase 1) in virgin and pregnant mice resulted in glomerular endotheliosis, hypertension, and albuminuria. L-arginine prevented the increase in blood pressure and albuminuria in Flt-1 pregnant but not in Flt-1 virgin mice. Flt-1 augmented arginine transport in pregnant but not in virgin dames. Ex vivo inhibition of CAT-2 leaving exclusively CAT-1 activity, decreased arginine transport velocities in Flt-1 animals more prominently in pregnant dames. Phosphorylated CAT-1/CAT-1 increased in pregnant, sFlt-1-pregnant, and sFlt-1 virgin mice. CAT-2 increased in Flt-1-pregnant and Flt-1-virgin dames. L-arginine augmented arginine transport in pregnant and Flt-pregnant mice and prevented the increase in pCAT-1 and CAT-2 expression. Glomerular cGMP (cyclic guanosine monophosphate) generation as a measure of eNOS activity was decreased in all Flt-1 treated animals. L-arginine abolished the decrease in cGMP levels only in Flt-1-pregnant mice. In conclusion, glomerular endothelial NO generation is compromised in Flt-1-pregnant mice because of CAT-1 inhibition induced by a combined effect of pregnancy and preeclampsia which involves: phosphorylation of CAT-1 and induction of CAT-2. These processes contribute to the clinical syndrome of preeclampsia in mice and are prevented by L-arginine.

Ultrapure Filter does not Confer Short-Term Benefits over Two Reverse Osmosis Systems in Chronic Hemodialysis Patients.

BACKGROUND: Dialysate purity contributes to the inflammatory response that afflicts hemodialysis patients. OBJECTIVES: To compare the clinical and laboratory effects of using ultrapure water produced by a water treatment system including two reverse osmosis (RO) units in series, with a system that also includes an ultrapure filter (UPF). METHODS: We performed a retrospective study in 193 hemodialysis patients during two periods: period A (no UPF, 6 months) and period B (same patients, with addition of UPF, 18 months), and a historical cohort of patients treated in the same dialysis unit 2 years earlier, which served as a control group. RESULTS: Mean C-reactive protein, serum albumin and systolic blood pressure worsened in period B compared to period A and in the controls. CONCLUSIONS: A double RO system to produce ultrapure water is not inferior to the use of ultrapure filters.

Malnutrition Risk in Hemodialysis Patients in Israel: Results of the Status of Nutrition In Hemodialysis Patients Survey Study.

BACKGROUND: Malnutrition is a frequently observed disorder in patients with chronic kidney disease (CKD) receiving hemodialysis (HD). While variously defined, malnutrition is a frequently observed condition among patients on HD. Prevalence estimates of malnutrition among Israeli HD patients have not been reported. OBJECTIVES: To survey nutrition intake in Israeli HD patients; estimate malnutrition risk prevalence; identify risk factors, and characterize malnutrition risk in HD patients. METHODS: A representative sample of 378 Israeli HD patients treated in hospital HD centers throughout the country were surveyed. Using the 24-h recall method, dietary intake was estimated and the chronologically corresponding biochemistry, anthropometric, and hemodynamic measures were recorded. Four categories of malnutrition risk were defined: "minimal": body mass index (BMI) > 23 kg/m2 and serum albumin > 3.8 g/dL; "mild": BMI < 23 kg/m2 and albumin > 3.8 g/dL; "moderate": BMI > 23 kg/m2 and albumin < 3.8 g/dL; "severe": BMI < 23 k/m2 and serum albumin < 3.8 g/dL. RESULTS: Elevated malnutrition risk was identified in 175 (46.3%) study participants, who were more likely to require feeding assistance, have major comorbidities, reduced hemoglobin, and elevated C-reactive protein. Oral nutrition supplementation was prescribed to only 14.3% of patients with elevated malnutrition risk. Intradialytic parenteral nutrition was recorded for 6 patients, all of whom had moderate or severe malnutrition risk. Less than one-third of patients met the guidelines for dietary intake of energy or protein, and this did not differ across malnutrition risk groups. DISCUSSION: Elevated malnutrition risk is a frequent finding in HD patients treated in hospital settings in Israel. Dietary intake does not meet guidelines but does not differ across malnutrition risk categories. Nutrition supplements are underused in HD patients with high malnutrition risk. There is a need to expand the survey to community HD centers.

Normal-range albuminuria in healthy subjects increases over time in association with hypertension and metabolic outcomes.

Albuminuria is a prognostic factor for mortality and cardiovascular events, even at low levels. Changes in albumin excretion are associated with end-stage renal disease and hypertension (HTN) in cohorts including high-risk participants. We aimed to investigate the evolvement of albumin excretion in healthy individuals with normal kidney function and normoalbuminuria, and possible associations with HTN and metabolic outcomes. The study cohort consisted of 1967 healthy adults with normal kidney function (estimated glomerular filtration rate ≥ 90 mL/min/1.73 m2; urine albumin to creatinine ratio [ACR] < 30 mg/g). Delta ACR slope was calculated as ACR difference between two consecutive visits divided by the time interval. During a mean follow-up period of 93.8 months, mean delta ACR slope was 0.27 ± 3.29 mg/g/year and was higher in participants with age >40 years, obesity, a high waist circumference, higher baseline ACR, HTN, prediabetes, and metabolic syndrome. Delta ACR slopes in the upper quartile predicted diabetes (OR = 1.31, P = .027) and albuminuria (4.34, P < .001). Upper quartile of ACR slopes correlated with a higher risk for new-onset HTN (1.249, P = .031). Delta systolic and diastolic blood pressures were associated with ACR slopes in addition to age, body mass index, and baseline ACR. In conclusion, accelerated change in ACR correlates with HTN and diabetes in healthy individuals with normal kidney function and normoalbuminuria.

Mineralocorticoid receptor blockade improves arginine transport and nitric oxide generation through modulation of cationic amino acid transporter-1 in endothelial cells.

Blockade of the mineralocorticoid receptor (MCR) has been shown to improve endothelial function far beyond blood pressure control. In the current studies we have looked at the effect of MCR antagonists on cationic amino acid transporter-1 (CAT-1), a major modulator of endothelial nitric oxide (NO) generation. Using radio-labeled arginine, {[3H] l-arginine} uptake was determined in human umbilical vein endothelial cells (HUVEC) following incubation with either spironolactone or eplerenone with or without silencing of MCR. Western blotting for CAT-1, PKCα and their phosphorylated forms were performed. NO generation was measured by using Griess reaction assay. Both Spironolactone and eplerenone significantly increased endothelial arginine transport, an effect which was further augmented by co-incubation with aldosterone, and blunted by either silencing of MCR or co-administration of amiloride. Following MCR blockade, we identified two bands for CAT-1. The addition of tunicamycin (an inhibitor of protein glycosylation) or MCR silencing resulted in disappearance of the extra band and prevented the increase in arginine transport. Only spironolactone decreased CAT-1 phosphorylation through inhibition of PKCα (CAT-1 inhibitor). Subsequently, incubation with either MCR antagonists significantly augmented NO2/NO3 levels (stable NO metabolites) and this was attenuated by silencing of MCR or tunicamycin. GO 6076 (PKCα inhibitor) intensified the increase of NO metabolites only in eplerenone treated cells. In conclusion spironolactone and eplerenone augment arginine transport and NO generation through modulation of CAT-1 in endothelial cells. Both MCR antagonists activate CAT-1 by inducing its glycosylation while only spironolactone inhibits PKCα.

Cancer Risk Among Children Undergoing Renal Replacement Therapy: Results From the Israel National Renal Replacement Therapy Registry, 1990-2012.

BACKGROUND: Patients with end-stage renal disease who undergo chronic renal replacement therapy (RRT) have a higher incidence of cancer. A limited number of studies addressed the risk for cancer in children exposed to RRT. The purpose of the present study was to examine whether children undergoing RRT in Israel are at increased risk for all-site and specific cancers. SUBJECTS AND METHODS: The study population comprised 674 children 0 to 19 years of age who were registered between January 1990 and December 2012 in the Israel National Renal Replacement Therapy Registry. The Registry database was linked with the Israel National Cancer Registry to trace cancer incidence. Variables associated with malignancy were estimated by univariate analysis. Standardized incidence ratios for cancer were calculated using the general Israel population 0 to 15 years of age, for the corresponding years 1990-2012, as a reference. RESULTS: Seventeen children developed cancer during the follow-up period. Younger age at RRT initiation was the only variable associated with malignancy in the univariate analysis (hazard ratio, 0.91; 95% confidence interval, 0.84-0.99; P=0.03). Cancer incidence was 6.7-fold higher among children undergoing RRT than the general population. CONCLUSIONS: Children treated by chronic RRT have a higher incidence of cancer than their peers, and therefore should be followed closely.

Bile acid receptors and the kidney.

PURPOSE OF REVIEW: Bile acids act as activating signals of endogenous renal receptors: the nuclear receptor farnesoid X receptor (FXR) and the membrane-bound G protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5). In recent years, bile acids have emerged as important for renal pathophysiology by activating FXR and TGR5 and transcription factors relevant for lipid, cholesterol and carbohydrate metabolism, as well as genes involved in inflammation and renal fibrosis. RECENT FINDINGS: Activation of bile acid receptors has a promising therapeutic potential in prevention of diabetic nephropathy and obesity-induced renal damage, as well as in nephrosclerosis. During the past decade, progress has been made in understanding the biology and mechanisms of bile acid receptors in the kidney and in the development of specific bile acid receptor agonists. SUMMARY: In this review, we discuss current knowledge on the roles of FXR and TGR5 in the physiology of the kidney and the latest advances made in development and characterization of bile acid analogues that activate bile acid receptors for treatment of renal disease.

Differences in quality of life between Jewish and Arab patients on hemodialysis.

PURPOSE: Higher health-related quality of life (HRQOL) in dialysis patients has been associated with fewer hospitalizations and lower mortality. Since Arab patients on dialysis have better survival rates than Jewish patients, we hypothesized that they would have higher HRQOL. We also studied the impact of several risk factors on HRQOL in each population. METHODS: Based on a national dialysis registry, patients from 64 hemodialysis units were recruited to participate. Patients who consented were interviewed face-to-face, using the Kidney Disease Quality of Life Short Form (KDQOL-SF36) questionnaire. RESULTS: Five hundred and fifty-eight (50.6%) Jewish and 544 (49.4%) Arab patients participated in the study. For Arab patients mean crude scores for the "mental component summary" and KDQOL scores were significantly lower than for Jewish patients [31.6 (95% Cl 30.0-33.3) vs. 38.0 (95% Cl 36.1-39.9), p < 0.0001 and 55.6 (95% Cl 54.5-56.7) vs. 59.8 (95% Cl 58.6-60.9), p < 0.0001, respectively]. Much lower scores were observed for Arabs in the "emotional role" and "work status" subscales. The two populations had similar general health assessments and albumin level. For both, HRQOL was positively associated with higher educational level, higher albumin level, and dialysis connection by fistula or graft; and negatively associated with low income and diabetes. HRQOL was negatively associated with previous cerebrovascular accident among Arabs and with female gender among Jews. CONCLUSIONS: Differences between Jews and Arabs in subscales related to psychosocial factors suggest that cultural differences in the perceptions of sickness and health may be relevant here. Future studies should explore such possibility and focus on the large gap in the "work status" subscale.

Vascular Endothelial Growth Factor Augments Arginine Transport and Nitric Oxide Generation via a KDR Receptor Signaling Pathway.

BACKGROUND/AIMS: Vascular endothelial growth factor (VEGF) is an endothelium-specific peptide that stimulates angiogenesis via two receptor tyrosine kinases, Flt-1 and KDR. Endothelial nitric oxide synthase (eNOS) plays a major role in VEGF signaling. Delivery of arginine to membrane bound eNOS by the cationic amino acid transporter-1 (CAT-1) has been shown to modulate eNOS activity. The current studies were designed to test the hypothesis that VEGF enhances eNOS activity via modulation of arginine transport by CAT-1. METHODS: Using radio-labeled arginine, {[3H] L-arginine} uptake was determined in human umbilical vein endothelial cells (HUVEC) following incubation with VEGF with and without silencing the VEGF receptors Flt-1 or KDR. Subsequently, western blotting for CAT-1, PKCα, ERK 1/2, JNK, and their phosphorylated forms were performed. NO generation was measured by the Griess reaction. RESULTS: VEGF (50 and 100 ng/ml) significantly augmented endothelial arginine transport in a time dependent manner, an effect which was prevented by Sunitinib (2 µM), a multi targeted receptor tyrosine kinase inhibitor. The increase in arginine transport velocities by VEGF was not affected by silencing Flt-1 while silencing KDR abrogated VEGF effect. Furthermore, incubating cells with 50 and 100 ng of VEGF for 30 minutes significantly augmented CAT-1 abundance. The expression of PKC-α, JNK, and ERK1/2 and their phosphorylated forms were unchanged following incubation of HUVEC with VEGF. The concentration of NO2/NO3 following incubation with VEGF was significantly higher than from untreated cells. This increase was significantly attenuated by silencing KDR. CONCLUSIONS: VEGF increases arginine transport via modulation of CAT-1 in endothelial cells. This effect is exclusively dependent on KDR rather than Flt-1.

Angiotensin converting-enzyme inhibition restores glomerular glycosaminoglycans in rat puromycin nephrosis.

BACKGROUND: Aberrant glomerular polyanionic charge of glycosaminoglycans (GAGs) and sialic acid expression has been observed in proteinuric human and experimental glomerular diseases. Angiotensin-converting enzyme inhibitors (ACEI) lower proteinuria and amend renal function deterioration via hemodynamic mechanisms. We tested the hypothesis that ACEI modulate proteinuria additionally by modifying glomerular GAGs. METHODS: In this study, we explored the effects of the ACEI enalapril on proteinuria and GAG synthesis in puromycin aminonucleoside (PAN)-treated rats. We employed cationic colloidal gold (CCG) localization in glomerular basement membranes (GBM) to identify GAGs by electron microscopy and determined sialic acid residues by immunohistochemical staining with lectins. To clarify ACEI effects on GAG production in vitro, we studied de novo GAG synthesis into newly synthesized proteoglycans in podocytes and mesangial cells using 35S incorporation. Cells were incubated with or without PAN, and with increasing doses of the ACEI enalaprilat. RESULTS: PAN rats developed severe proteinuria that was significantly improved by enalapril treatment. In non-treated PAN rats GBM GAGs were reduced, whereas in the enalapril-treated group GBM GAGs were significantly increased to control levels. Enalapril did not affect glomerular sialic acid. Furthermore, in cultured podocytes and mesangial cells PAN decreased de novo GAG synthesis, an effect which was significantly ameliorated by enalaprilat treatment. CONCLUSION: Treatment with ACEI improves permselectivity properties of the glomerular capillary wall by maintaining its GAG content. This finding provides an additional new mechanism, whereby ACEI exert anti-proteinuric effects.