Progressive CKD Research Articles

Rate of kidney function decline and factors predicting progression of kidney disease in type 2 diabetes mellitus patients with reduced kidney function: A nationwide retrospective cohort study.

Currently, the data on independent risk factors for the progression of kidney disease in type 2 diabetes mellitus (T2DM) patients with CKD are limited. This study aimed to investigate CKD progression in T2DM patients who have reduced kidney function with baseline estimated glomerular filtration rate (eGFRs) between 15 and 59 mL/min/1.73 m2 . This study was composed of a nationwide retrospective cohort of adult T2DM patients from 831 public hospitals in Thailand during the year 2015. T2DM patients with CKD stages 3 and 4 were followed up, until development of CKD stage 5, requirement of chronic dialysis, loss to follow-up, death, or 31 May 2018, whichever came first. Cox proportional hazard regression was utilized for analysis. A total of 8464 participants were included; 30.4% were male. The mean age was 69 ± 10 years. The mean eGFR was 45 ± 11 mL/min/1.73 m2 . The incidence of CKD stage 5 or the need for chronic dialysis was 16.4 per 1000 person-years. The annual rate of eGFR decline during a mean follow-up of 29 months was -2.3 mL/min/1.73 m2 ; 14.4% had a rapid decline in eGFR. The risk factors associated with progression to CKD stage 5 or the need for chronic dialysis were diabetes duration, systolic blood pressure, serum uric acid, albuminuria, and baseline eGFR. Conversely, older age and the use of renin-angiotensin aldosterone system blockade were associated with decreased risks for rapid CKD progression and incidence CKD stage 5 or dialysis. This study identifies multiple predictive risk factors that support a multifaceted approach to prevent progression of advanced CKD.

Dickkopf 3-a novel biomarker of the 'kidney injury continuum'.

Chronic kidney disease (CKD) is a global public health problem accompanied by substantial comorbidities and reduced life expectancy. In this respect, progressive CKD leading to uraemia can be seen as a systemic disease with a critical impact on virtually all organ systems. Therefore, it is of particular importance to identify patients with ongoing CKD progression, which is challenging, because the individual course of CKD is difficult to predict. Patterns of progression in CKD patients include linear and non-linear trajectories of GFR loss, but kidney function can also remain stable for years. Moreover, a substantial GFR decline may occur in the absence of higher-grade albuminuria (non-proteinuric CKD), rendering the measurement of albuminuria less reliable for progression prediction in such individuals. In the present review, we focus on the recently identified glycoprotein Dickkopf-3 (DKK3) as a stress-induced, renal tubular epithelial cell-derived, pro-fibrotic molecule. In experimental CKD models, DKK3 promoted renal tubulointerstitial fibrosis through modulation of the canonical Wnt/β-catenin signalling pathway. In clinical studies, increased urinary DKK3 levels identified patients at high risk for short-term CKD progression, regardless of the cause of kidney disease, baseline kidney function and albuminuria. Moreover, increased urinary DKK3 levels are associated with a high risk for acute kidney injury and the subsequent loss of kidney function after cardiac surgery. These findings highlight DKK3 as a mediator of renal tubular cell damage in kidney injury and short-term progression of kidney disease, with potential therapeutic implications.

Nephrotoxicity of Antimicrobials and Antibiotics.

Medication-induced nephrotoxicity remains one of the most common causes of acute kidney injury (AKI) among hospitalized patients. Within the extensive group of medications associated with AKI, antibiotics and other antimicrobials are well recognized triggers of structural and functional renal impairment. Clinical manifestations range from mild forms of tubular injury to significant deterioration of kidney function requiring acute renal replacement therapy. Several mechanisms are described, although the most frequent are acute interstitial nephritis, acute tubular necrosis, intratubular crystal deposition, and proximal/distal tubulopathy with electrolyte wasting abnormalities. General risk factors for antimicrobial-induced AKI include pre-existing chronic kidney disease, and concomitant use of medication with nephrotoxic potential. Prevention and early recognition of AKI represent the standard approach to mitigate AKI and avoid morbidity.

Characterization of patients with chronic kidney disease admitted at Edward Francis Small Teaching Hospital in the Gambia: a descriptive cross-sectional study

Introduction: chronic renal failure is a devastating problem for patients and their families. This situation is worse in most developing countries where ESRD constitutes a death sentence as renal replacement therapy is often unavailable or unaffordable. This study aimed to determine the socio-demographic characteristics and risk factors for progression CKD. Settings and Design: a descriptive study was conducted among patients admitted in the haemodialysis and medical wards from September to November 2019.

Change in Dyslipidemia with Declining Glomerular Filtration Rate and Increasing Proteinuria in Children with CKD.

Dyslipidemia, a risk factor for cardiovascular disease, is common in CKD but its change over time and how that change is influenced by concurrent progression of CKD have not been previously described. In the CKD in Children study we prospectively followed children with progressive CKD and utilized multivariable, linear mixed-effects models to quantify the longitudinal relationship between within-subject changes in lipid measures (HDL cholesterol, non-HDL cholesterol, triglycerides) and within-subject changes in GFR, proteinuria, and body mass index (BMI). A total of 508 children (76% nonglomerular CKD, 24% glomerular CKD) had 2-6 lipid measurements each, with a median follow-up time of 4 (interquartile range [IQR], 2.1-6.0) years. Among children with nonglomerular CKD, dyslipidemia was common at baseline (35%) and increased significantly as children aged; 43% of children with glomerular CKD had dyslipidemia at baseline and demonstrated persistent levels as they aged. Longitudinal increases in proteinuria were independently associated with significant concomitant increases in non-HDL cholesterol (nonglomerular: 4.9 [IQR, 3.4-6.4] mg/dl; glomerular: 8.5 [IQR, 6.0-11.1] mg/dl) and triglycerides (nonglomerular: 3% [IQR, 0.8%-6%]; glomerular: 5% [IQR, 0.6%-9%]). Decreases in GFR over follow-up were significantly associated with concomitant decreases of HDL cholesterol in children with nonglomerular CKD (-1.2 mg/dl; IQR, -2.1 to -0.4 mg/dl) and increases of non-HDL cholesterol in children with glomerular CKD (3.9 mg/dl; IQR, 1.4-6.5 mg/dl). The effects of increased BMI also affected multiple lipid changes over time. Collectively, glomerular CKD displayed stronger, deleterious associations between within-subject change in non-HDL cholesterol (9 mg/dl versus 1.2 mg/dl; P<0.001) and triglycerides (14% versus 3%; P=0.004), and within-subject change in BMI; similar but quantitatively smaller differences between the two types of CKD were noted for associations of within-subject change in lipids to within-subject change in GFR and proteinuria. Dyslipidemia is a common and persistent complication in children with CKD and it worsens in proportion to declining GFR, worsening proteinuria, and increasing BMI.

Plasma C-Terminal Agrin Fragment (CAF) as an Early Marker for Kidney Function in Patients with Chronic Kidney Disease

AbstractBackground: CKD is defined by the presence of renal damage or impaired renal function for three or more months, irrespective of the cause. The presence of the damage or impaired function for at least three months is important to distinguish CKD from AKI. C-terminal Agrin Fragment (CAF) was found in the basement membrane of the kidney and cleared from circulation by glomerular filtration.Aim of Study: To evaluate plasma level of C-terminal agrin fragment as an early detector of renal function impairment in patients with chronic kidney disease.Methods: The study was carried on two groups Group (I): 20 healthy persons as a control group and Group (II): 60 CKD patients. Patients were selected from Internal Medicine Department, Tanta University Hospital. We excluded patients suffered from inflammatory, autoimmune, infectious disorders and malignant diseases, also patients with acute underlying illness were excluded from the study. Informed consents were taken from all participants and the privacy of the data were greatly considered. Complete clinical examination including: Body Mass Index (BMI) calculation and routine laboratory investigations including Complete Blood Count (CBC), blood urea, serum creatinine, eGFR, 24h proteinuria, sodium and potassium, CRP and specific investigation: Plasma level of C-terminal Agrin Fragment (CAF) measurements by ELISA technique was done.Results: Plasma CAF showed statistical significance increase in patients group than control healthy groups (p<.001) with gradual increase in its level in progressive CKD stages. There was significant positive correlation between plasma CAF, serum creatinine and blood urea (p<.001) while there was significant negative correlation between plasma CAF and eGFR (p<.001). There was significant increase in CAF in early stage 1 CKD group compared to control group (p<.001). Plasma CAF wasn't affected by age, sex and muscle mass in contrast to creatinine which was affected by them.Conclusion: The results of this study showed that plasma CAF was increasing with the progression of CKD stages and it was more sensitive and specific than serum creatinine, blood urea and eGFR in estimation of staging CKD. Plasma CAF also can differentiate between healthy individuals and stage 1 CKD patients, so measurement of plasma level of CAF may represent a promising bio-marker of early kidney damage detection and progression to ESKD.

SUN-338 CHRONIC KIDNEY DISEASE IN A SAMOAN COMMUNITY

Maori and Pacific people have a 3 to 5 fold risk developing end Stage Kidney Disease (ESKD) compared to New Zealand Europeans with the major aetiology being type 2 diabetes (1). In a NZ community based prevalence study, Pacific people had a 2.56 fold higher risk of CKD, controlling for diabetes (2). Likewise Pacific people (predominantly Samoan) in NZ with a family history of ESKD have an increased risk of nephropathy independent of diabetes (3). This cross sectional pilot study aimed to identify the prevalence of proteinuria in a Samoan community in absence of diabetes as a way of identifying potential risk for progressive CKD.

Urinary Biomarkers of Renal Fibrosis.

Renal fibrosis is the common pathological pathway of progressive CKD. The commonly used biomarkers in clinical practice are not optimal to detect injury or predict prognosis. Therefore, it is crucial to develop novel biomarkers to allow prompt intervention. Urine serves as a valuable resource of biomarker discovery for kidney diseases. Owing to the rapid development of omics platforms and bioinformatics, research on novel urinary biomarkers for renal fibrosis has proliferated in recent years. In this chapter, we discuss the current status and provide basic knowledge in this field. We present novel promising biomarkers including tubular injury markers, proteins related to activated inflammation/fibrosis pathways, CKD273, transcriptomic biomarkers, as well as metabolomic biomarkers. Furthermore, considering the complex nature of the pathogenesis of renal fibrosis, we also highlight the combination of biomarkers to further improve the diagnostic and prognostic performance.

Type 2 diabetes treatment and progression of chronic kidney disease in Italian family practice

Progressive chronic kidney disease represents a dreadful complication of type 2 diabetes mellitus (T2DM). We tested the pattern of use and the renal effects of old glucose-lowering drugs in T2DM patients cared for by Italian general practitioners (GPs). Data of 2606 T2DM patients were extracted from the databases of GPs, who do not have access to the most recent glucose-lowering drugs in Italy. The rate of kidney function decline was calculated by CKD-EPIcr, based on two consecutive creatinine values. Metformin was used in 55% of cases, either alone or with sulfonylureas/repaglinide, across the whole spectrum of CKD (from 66% in stage G1 to only 8% in G4). Sulfonylurea use peaked at 21-22% in stage G2-G3a, whereas repaglinide use significantly increased from 8% in G1 to 22% in G4. The median rate of CKD decline was - 1.64mL/min/1.73m2 per year; it was higher in G1 (- 3.22 per year) and progressively lower with CKD severity. 826 cases (31.7%) were classified as fast progressors (eGFR decline more negative than - 5mL/min/1.73m2 per year). The risk of fast progressing CKD was associated with increasing BMI, albuminuria, and sulfonylurea use, alone (OR, 1.47; 95% confidence interval, 1.16-1.85), or in association with metformin (OR, 1.40; 95% CI 1.04-1.88). No associations were demonstrated for metformin, cardiovascular and lipid lowering drug use. In the setting of Italian family practice, sulfonylurea use is associated with progressive CKD in patients with T2DM. Metformin, at doses progressively reduced according to CKD stages, as recommended by guidelines, is not associated with fast progression.

Nephrolithiasis secondary to inherited defects in the thick ascending loop of henle and connecting tubules.

Twin and genealogy studies suggest a strong genetic component of nephrolithiasis. Likewise, urinary traits associated with renal stone formation were found to be highly heritable, even after adjustment for demographic, anthropometric and dietary covariates. Recent high-throughput sequencing projects of phenotypically well-defined cohorts of stone formers and large genome-wide association studies led to the discovery of many new genes associated with kidney stones. The spectrum ranges from infrequent but highly penetrant variants (mutations) causing mendelian forms of nephrolithiasis (monogenic traits) to common but phenotypically mild variants associated with nephrolithiasis (polygenic traits). About two-thirds of the genes currently known to be associated with nephrolithiasis code for membrane proteins or enzymes involved in renal tubular transport. The thick ascending limb of Henle and connecting tubules are of paramount importance for renal water and electrolyte handling, urinary concentration and maintenance of acid-base homeostasis. In most instances, pathogenic variants in genes involved in thick ascending limb of Henle and connecting tubule function result in phenotypically severe disease, frequently accompanied by nephrocalcinosis with progressive CKD and to a variable degree by nephrolithiasis. The aim of this article is to review the current knowledge on kidney stone disease associated with inherited defects in the thick ascending loop of Henle and the connecting tubules. We also highlight recent advances in the field of kidney stone genetics that have implications beyond rare disease, offering new insights into the most common type of kidney stone disease, i.e., idiopathic calcium stone disease.

Novel Urinary Biomarkers For Improved Prediction Of Progressive eGFR Loss In Early Chronic Kidney Disease Stages And In High Risk Individuals Without Chronic Kidney Disease

Chronic kidney disease is associated with increased risk of CKD progression and death. Therapeutic approaches to limit progression are limited. Developing tools for the early identification of those individuals most likely to progress will allow enriching clinical trials in high risk early CKD patients. The CKD273 classifier is a panel of 273 urinary peptides that enables early detection of CKD and prognosis of progression. We have generated urine capillary electrophoresis-mass spectrometry-based peptidomics CKD273 subclassifiers specific for CKD stages to allow the early identification of patients at high risk of CKD progression. In the validation cohort, the CKD273 subclassifiers outperformed albuminuria and CKD273 classifier for predicting rapid loss of eGFR in individuals with baseline eGFR > 60 ml/min/1.73 m2. In individuals with eGFR > 60 ml/min/1.73 m2 and albuminuria <30 mg/day, the CKD273 subclassifiers predicted rapid eGFR loss with AUC ranging from 0.797 (0.743–0.844) to 0.736 (0.689–0.780). The association between CKD273 subclassifiers and rapid progression remained significant after adjustment for age, sex, albuminuria, DM, baseline eGFR, and systolic blood pressure. Urinary peptidomics CKD273 subclassifiers outperformed albuminuria and CKD273 classifier for predicting the risk of rapid CKD progression in individuals with eGFR > 60 ml/min/1.73 m2. These CKD273 subclassifiers represented the earliest evidence of rapidly progressive CKD in non-albuminuric individuals with preserved renal function.

Diagnosis and management of non-dialysis chronic kidney disease in ambulatory care: a systematic review of clinical practice guidelines

BackgroundChronic kidney disease (CKD) is age-dependent and has a high prevalence in the general population. Most patients are managed in ambulatory care. This systematic review provides an updated overview of quality and content of international clinical practice guidelines for diagnosis and management of non-dialysis CKD relevant to patients in ambulatory care.MethodsWe identified guidelines published from 2012-to March 2018 in guideline portals, databases and by manual search. Methodological quality was assessed with the Appraisal of Guidelines for Research and Evaluation II instrument. Recommendations were extracted and evaluated.ResultsEight hundred fifty-two publications were identified, 9 of which were eligible guidelines. Methodological quality ranged from 34 to 77%, with domains “scope and purpose” and “clarity of presentation” attaining highest and “applicability” lowest scores. Guidelines were similar in recommendations on CKD definition, screening of patients with diabetes and hypertension, blood pressure targets and referral of patients with progressive or stage G4 CKD. Definition of high risk groups and recommended tests in newly diagnosed CKD varied.ConclusionsGuidelines quality ranged from moderate to high. Guidelines generally agreed on management of patients with high risk or advanced CKD, but varied in regarding the range of recommended measurements, the need for referrals to nephrology, monitoring intervals and comprehensiveness. More research is needed on efficient management of patients with low risk of CKD progression to end stage renal disease.

P6025Myocardial ultrastructural changes in progressive CKD: the key intermediaries of “uraemic” cardiomyopathy?

P6025Myocardial ultrastructural changes in progressive CKD: the key intermediaries of “uraemic” cardiomyopathy?

Somatic Mutations in Renal Cyst Epithelium in Autosomal Dominant Polycystic Kidney Disease.

Autosomal dominant polycystic kidney disease (ADPKD) is a ciliopathy caused by mutations in PKD1 and PKD2 that is characterized by renal tubular epithelial cell proliferation and progressive CKD. Although the molecular mechanisms involved in cystogenesis are not established, concurrent inactivating constitutional and somatic mutations in ADPKD genes in cyst epithelium have been proposed as a cellular recessive mechanism. We characterized, by whole-exome sequencing (WES) and long-range PCR techniques, the somatic mutations in PKD1 and PKD2 genes in renal epithelial cells from 83 kidney cysts obtained from nine patients with ADPKD, for whom a constitutional mutation in PKD1 or PKD2 was identified. Complete sequencing data by long-range PCR and WES was available for 63 and 65 cysts, respectively. Private somatic mutations of PKD1 or PKD2 were identified in all patients and in 90% of the cysts analyzed; 90% of these mutations were truncating, splice site, or in-frame variations predicted to be pathogenic mutations. No trans-heterozygous mutations of PKD1 or PKD2 genes were identified. Copy number changes of PKD1 ranging from 151 bp to 28 kb were observed in 12% of the cysts. WES also identified significant mutations in 53 non-PKD1/2 genes, including other ciliopathy genes and cancer-related genes. These findings support a cellular recessive mechanism for cyst formation in ADPKD caused primarily by inactivating constitutional and somatic mutations of PKD1 or PKD2 in kidney cyst epithelium. The potential interactions of these genes with other ciliopathy- and cancer-related genes to influence ADPKD severity merits further evaluation.

Nephrotoxicity and Chinese Herbal Medicine.

Chinese herbal medicine has been practiced for the prevention, treatment, and cure of diseases for thousands of years. Herbal medicine involves the use of natural compounds, which have relatively complex active ingredients with varying degrees of side effects. Some of these herbal medicines are known to cause nephrotoxicity, which can be overlooked by physicians and patients due to the belief that herbal medications are innocuous. Some of the nephrotoxic components from herbs are aristolochic acids and other plant alkaloids. In addition, anthraquinones, flavonoids, and glycosides from herbs also are known to cause kidney toxicity. The kidney manifestations of nephrotoxicity associated with herbal medicine include acute kidney injury, CKD, nephrolithiasis, rhabdomyolysis, Fanconi syndrome, and urothelial carcinoma. Several factors contribute to the nephrotoxicity of herbal medicines, including the intrinsic toxicity of herbs, incorrect processing or storage, adulteration, contamination by heavy metals, incorrect dosing, and interactions between herbal medicines and medications. The exact incidence of kidney injury due to nephrotoxic herbal medicine is not known. However, clinicians should consider herbal medicine use in patients with unexplained AKI or progressive CKD. In addition, exposure to herbal medicine containing aristolochic acid may increase risk for future uroepithelial cancers, and patients require appropriate postexposure screening.

Tonicity-Responsive Enhancer-Binding Protein Mediates Hyperglycemia-Induced Inflammation and Vascular and Renal Injury.

Diabetic nephropathy (DN) has become the single leading cause of ESRD in developed nations. Bearing in mind the paucity of effective treatment for DN and progressive CKD, novel targets for treatment are sorely needed. We previously reported that increased activity of tonicity-responsive enhancer-binding protein (TonEBP) in monocytes was associated with early DN in humans. We now extend these findings by testing the hypotheses that TonEBP in macrophages promotes hyperglycemia-mediated proinflammatory activation and chronic renal inflammation leading to DN and CKD, and TonEBP genetic variability in humans is associated with inflammatory, renal, and vascular function-related phenotypes. In a mouse model of DN, compared with the wild-type phenotype, TonEBP haplodeficiency associated with reduced activation of macrophages by hyperglycemia, fewer macrophages in the kidney, lower renal expression of proinflammatory genes, and attenuated DN. Furthermore, in a cohort of healthy humans, genetic variants within TonEBP associated with renal function, BP, and systemic inflammation. One of the genetic variants associated with renal function was replicated in a large population-based cohort. These findings suggest that TonEBP is a promising target for minimizing diabetes- and stress-induced inflammation and renovascular injury.

Autosomal Dominant Tubulointerstitial Kidney Disease.

There are 3 major forms of autosomal dominant tubulointerstitial kidney disease (ADTKD): ADTKD due to UMOD mutations, MUC1 mutations, and mutations in the REN gene encoding renin. Lack of knowledge about these conditions contributes to frequent nondiagnosis, but with even limited knowledge, nephrologists can easily obtain a diagnosis and improve patient care. There are 3 cardinal features of these disorders: (1) the conditions are inherited in an autosomal dominant manner and should be considered whenever both a parent and child suffer from kidney disease; the presence of even more affected family members provides further support. (2) These conditions are associated with a bland urinary sediment, ruling out glomerular disorders. (3) There is a variable rate of decline in kidney function. The mean age of ESRD is approximately 45, but the range is from 17 to >75. ADTKD-UMOD is often but not always associated with gout in the teenage years. ADKTKD-REN is associated with signs of hyporeninemia: mild hypotension, mild hyperkalemia, anemia in childhood, and hyperuricemia and gout in the teenage years. The only clinical manifestation of ADTKD-MUC1 is slowly progressive CKD. Diagnosis should be made by genetic testing, and kidney biopsy should be avoided.

Diet as a system: an observational study investigating a multi-choice system of moderately restricted low-protein diets.

BackgroundThere is no single, gold-standard, low-protein diet (LPD) for CKD patients; the best compliance is probably obtained by personalization. This study tests the hypothesis that a multiple choice diet network allows patients to attain a good compliance level, and that, in an open-choice system, overall results are not dependent upon the specific diet, but upon the clinical characteristics of the patients.MethodsObservational study: Three LPD options were offered to all patients with severe or rapidly progressive CKD: vegan diets supplemented with alpha-ketoacids and essential aminoacids; protein-free food in substitution of normal bread and pasta; other (traditional, vegan non supplemented and tailored). Dialysis-free follow-up and survival were analyzed by Kaplan Meier curves according to diet, comorbidity and age.Compliance and metabolic control were estimated in 147 subjects on diet at March 2015, with recent complete data, prescribed protein intake 0.6 g/Kg/day. Protein intake was assessed by Maroni Mitch formula.ResultsFour hundreds and forty nine patients followed a LPD in December, 2007- March, 2015 (90% moderately restricted LPDs, 0.6 g/Kg/day of protein, 10% at lower targets); age (median 70 (19–97)) and comorbidity (Charlson index: 7) characterized our population as being in line with the usual CKD European population. Median e-GFR at start of the diet was 20 mL/min, 33.2% of the patients were diabetics. Baseline data differ significantly across diets: protein-free schemas are preferred by older, high-comorbidity patients (median age 76 years, Charlson index 8, GFR 20.5 mL/min, Proteinuria: 0.3 g/day), supplemented vegan diets by younger patients with lower GFR and higher proteinuria (median age 65 years, Charlson index 6, GFR 18.9 mL/min; Proteinuria: 1.2 g/day); other diets are chosen by an intermediate population (median age 71 years, Charlson index 6; GFR 22.5 mL/min; Proteinuria: 0.9 g/day); (p <0.001 for age, Charlson index, proteinuria, GFR). Adherence was good, only 1.1% of the patients were lost to follow-up and protein intake was at target in most of the cases with no differences among LPDs (protein intake: 0.47 (0.26–0.86) g/Kg/day). After adjustment for confounders, and/or selection of similar populations, no difference in mortality or dialysis start was observed on the different LPDs. Below the threshold of e-GFR 15 mL/min, 50% of the patients remain dialysis free for at least two years.ConclusionA multiple choice LPD system may allow reaching good adherence, without competition among diets, and with promising results in terms of dialysis-free follow-up. The advantages with respect to a non-customized approach deserve confirmation in further comparative studies or RCTs.

Renal Aging: Causes and Consequences.

Individuals age >65 years old are the fastest expanding population demographic throughout the developed world. Consequently, more aged patients than before are receiving diagnoses of impaired renal function and nephrosclerosis-age-associated histologic changes in the kidneys. Recent studies have shown that the aged kidney undergoes a range of structural changes and has altered transcriptomic, hemodynamic, and physiologic behavior at rest and in response to renal insults. These changes impair the ability of the kidney to withstand and recover from injury, contributing to the high susceptibility of the aged population to AKI and their increased propensity to develop subsequent progressive CKD. In this review, we examine these features of the aged kidney and explore the various validated and putative pathways contributing to the changes observed with aging in both experimental animal models and humans. We also discuss the potential for additional study to increase understanding of the aged kidney and lead to novel therapeutic strategies.

A Randomized, Controlled Trial of Rituximab in IgA Nephropathy with Proteinuria and Renal Dysfunction.

IgA nephropathy frequently leads to progressive CKD. Although interest surrounds use of immunosuppressive agents added to standard therapy, several recent studies have questioned efficacy of these agents. Depleting antibody-producing B cells potentially offers a new therapy. In this open label, multicenter study conducted over 1-year follow-up, we randomized 34 adult patients with biopsy-proven IgA nephropathy and proteinuria >1 g/d, maintained on angiotensin-converting enzyme inhibitors or angiotensin receptor blockers with well controlled BP and eGFR<90 ml/min per 1.73 m2, to receive standard therapy or rituximab with standard therapy. Primary outcome measures included change in proteinuria and change in eGFR. Median baseline serum creatinine level (range) was 1.4 (0.8-2.4) mg/dl, and proteinuria was 2.1 (0.6-5.3) g/d. Treatment with rituximab depleted B cells and was well tolerated. eGFR did not change in either group. Rituximab did not alter the level of proteinuria compared with that at baseline or in the control group; three patients in each group had ≥50% reduction in level of proteinuria. Serum levels of galactose-deficient IgA1 or antibodies against galactose-deficient IgA1 did not change. In this trial, rituximab therapy did not significantly improve renal function or proteinuria assessed over 1 year. Although rituximab effectively depleted B cells, it failed to reduce serum levels of galactose-deficient IgA1 and antigalactose-deficient IgA1 antibodies. Lack of efficacy of rituximab, at least at this stage and severity of IgA nephropathy, may reflect a failure of rituximab to reduce levels of specific antibodies assigned salient pathogenetic roles in IgA nephropathy.