Rituximab or Cyclosporine in the Treatment of Membranous Nephropathy.

BACKGROUND: B-cell anomalies play a role in the pathogenesis of membranous nephropathy. B-cell depletion with rituximab may therefore be noninferior to treatment with cyclosporine for inducing and maintaining a complete or partial remission of proteinuria in patients with this condition. METHODS: We randomly assigned patients who had membranous nephropathy, proteinuria of at least 5 g per 24 hours, and a quantified creatinine clearance of at least 40 ml per minute per 1.73 m2 of body-surface area and had been receiving angiotensin-system blockade for at least 3 months to receive intravenous rituximab (two infusions, 1000 mg each, administered 14 days apart; repeated at 6 months in case of partial response) or oral cyclosporine (starting at a dose of 3.5 mg per kilogram of body weight per day for 12 months). Patients were followed for 24 months. The primary outcome was a composite of complete or partial remission of proteinuria at 24 months. Laboratory variables and safety were also assessed. RESULTS: A total of 130 patients underwent randomization. At 12 months, 39 of 65 patients (60%) in the rituximab group and 34 of 65 (52%) in the cyclosporine group had a complete or partial remission (risk difference, 8 percentage points; 95% confidence interval [CI], -9 to 25; P = 0.004 for noninferiority). At 24 months, 39 patients (60%) in the rituximab group and 13 (20%) in the cyclosporine group had a complete or partial remission (risk difference, 40 percentage points; 95% CI, 25 to 55; P<0.001 for both noninferiority and superiority). Among patients in remission who tested positive for anti-phospholipase A2 receptor (PLA2R) antibodies, the decline in autoantibodies to anti-PLA2R was faster and of greater magnitude and duration in the rituximab group than in the cyclosporine group. Serious adverse events occurred in 11 patients (17%) in the rituximab group and in 20 (31%) in the cyclosporine group (P = 0.06). CONCLUSIONS: Rituximab was noninferior to cyclosporine in inducing complete or partial remission of proteinuria at 12 months and was superior in maintaining proteinuria remission up to 24 months. (Funded by Genentech and the Fulk Family Foundation; MENTOR ClinicalTrials.gov number, NCT01180036.).

Infection-related glomerulonephritis mimicking lupus nephritis.

The glomerulonephritis (GN) of granulomatosis polyangiitis is described as "pauci immune" because the glomeruli show little or no evidence of immune complex deposition by immunofluorescence or electron microscopy. Here we describe a severe crescentic GN in which the patient was myeloperoxidase-antineutrophil cytoplasmic antibodies (MPO-ANCA) positive, and on renal biopsy the glomeruli were pauci immune (there were only a few electron-dense deposits). However, by immunofluorescence the glomeruli showed "full-house" staining (the glomeruli stained positive for C1q, C3, IgG, IgA, and IgM). The latter staining pattern would be consistent with that seen in patients with lupus-like GN or with severe crescentic GN as a result of bacterial infection. So, should this patient receive high-dose immunosuppressive therapy and steroid therapy to treat presumed autoimmune GN, or should the patient receive intensive antibiotic therapy to treat a presumed underlying severe infection? This dilemma was soon resolved because the patient's blood culture returned positive for Streptococcus mutans and cardiac echo showed evidence of bacterial endocarditis. This report provides further detail regarding the patient's clinical issues.

What every nephrologist needs to know about hydroxychloroquine toxicity
.

Hydroxychloroquine (HCQ) has become the rheumatologists's "Swiss army knife" when it comes to managing the rheumatologic manifestations of SLE and other auto-immune disorders. By contrast, nephrologists are much less comfortable in managing the multifaceted effect of HCQ. As a result, nephrologists are inclined to abdicate their responsibility for HCQ management, if this therapy was initiated by a rheumatologist. This report describes such a situation, which had devastating consequences for the patient. On this basis we suggest that this report is a story worth telling, and should encourage the nephrologist to be more involved in their patients' HCQ management.

Commentary on the Current Guidelines for the Diagnosis of Lupus Nephritis Flare.

PURPOSE OF REVIEW: Lupus nephritis flare is a frequent complication in patients with systemic lupus erythematosus. Recognizing disease activity is crucial in lupus nephritis management. Proteinuria magnitude and urine sediment change are major clinical indicators of lupus nephritis activity. This work updates these insights in light of recent findings regarding proteinuria quantification and urine sediment analyses. RECENT FINDINGS: Currently, BILAG and SLEDAI estimate proteinuria magnitude based on the protein/creatinine ratio of "spot" (single void collections) or "intended" 24-h urine collections without specifying the extent to which the collection approaches a 24-h collection. As discussed here, and based on our recently published work, these approaches often incur serious errors that can adversely affect SLE patient management. Also incorporated into this work is a new analysis of the clinical significance of urine sediment hematuria and pyuria changes with regard to recent-onset SLE glomerulonephritis (GN) flare. This analysis is based on a prospective study of urine sediment changes in the Ohio SLE Study, which was an NIH-sponsored prospective observational study of SLE GN patients with SLE flare of recent onset. We propose that BILAG and SLEDAI renal flare criteria can be made more rigorous by incorporating recently published insights into proteinuria quantification using the protein/creatinine ratio of an intended 24-h urine collection that is at least 50% complete based on its creatinine content. Also proposed are new insights into the interpretation of urine sediment hematuria and pyuria based on findings from the Ohio SLE Study.

Anticoagulant-Related Nephropathy.

Anticoagulant-related nephropathy (ARN) is a newly recognized form of AKI in which overanticoagulation causes profuse glomerular hemorrhage, which manifests on renal biopsy as numerous renal tubules filled with red cells and red cell casts. The glomeruli show changes, but they are not sufficient to account for the glomerular hemorrhage. We were the first to study ARN, and since then, our work has been confirmed by numerous other investigators. Oral anticoagulants have been in widespread use since the 1950s; today, >2 million patients with atrial fibrillation take an oral anticoagulant. Despite this history of widespread and prolonged exposure to oral anticoagulants, ARN was discovered only recently, suggesting that the condition may be a rare occurrence. This review chronicles the discovery of ARN, its confirmation by others, and our animal model of ARN. We also provide new data on analysis of "renal events" described in the post hoc analyses of three pivotal anticoagulation trials and three retrospective analyses of large clinical databases. Taken together, these analyses suggest that ARN is not a rare occurrence in the anticoagulated patient with atrial fibrillation. However, much work needs to be done to understand the condition, particularly prospective studies, to avoid the biases inherent in post hoc and retrospective analyses. Finally, we provide recommendations regarding the diagnosis and management of ARN on the basis of the best information available.

Bacterial endocarditis manifesting as autoimmune pulmonary renal syndrome: ANCA-associated lung hemorrhage and pauci-immune crescentic glomerulonephritis
.

The etiology of pulmonary renal syndrome can be broadly divided into infectious and autoimmune (predominantly ANCA vasculitis). The importance of timely differentiating between them stems from the deleterious effects of their respective treatment if misdiagnosed. Serology and tissue evaluation by pathology are employed to aid in this, however, in rare cases, this can be difficult. We present a case of infectious endocarditis that presented with pulmonary renal syndrome but had positive ANCA serology and a pauci-immune glomerulonephritis picture on kidney biopsy that posed diagnostic difficulty. Factors most helpful in differentiating between the two conditions are highlighted as well as treatment options.
.

Abatacept efficacy in steroid-resistant minimal-change disease revealed by the speed of proteinuria reduction after the start of abatacept
.

A unique characteristic of the response of minimal-change disease (MCD) or focal and segmental glomerulosclerosis (FSGS) to steroid therapy is that the remission of proteinuria occurs quickly, for example, within 4 - 6 weeks of the onset of steroid therapy, even in those with severe nephrotic syndrome. Remission of proteinuria in MCD and FSGS can also occur spontaneously (not steroid induced). However, spontaneous remission usually proceeds over several months or longer. Recently, there have been several reports that abatacept can induce proteinuria remission in MCD and FSGS. These claims, however, are dubious because either the remission occurred slowly over several months of abatacept therapy, or remission occurred within a few weeks of abatacept therapy, but the patient was also receiving therapies that could have accounted for the remission of proteinuria. Our case is unique in that his severe steroid- and cyclosporine-resistant MCD remitted acutely while receiving abatacept, and there was no other plausible explanation for the acute remission of his MCD.
.

The Urine Preservative Acetic Acid Degrades Urine Protein: Implications for Urine Biorepositories and the AASK Cohort Study.

Patients enrolled in the African American Study of Kidney Disease and Hypertension (AASK) Cohort Study who exhibited overt proteinuria have been reported to show high nonalbumin proteinuria (NAP), which is characteristic of a tubulopathy. To determine whether African American Study of Kidney Disease and Hypertension nephropathy (AASK-N) is a tubulopathy, we obtained urine samples of 37 patients with AASK-N, with 24-hour protein-to-creatinine ratios (milligrams per milligram) ranging from 0.2 to 1.0, from the National Institute of Diabetes and Digestive Kidney Diseases repository and tested for seven markers of tubular proteinuria. By protocol, each sample had been collected in acetic acid (0.5%; mean final concentration). Compared with samples from patients with lupus nephritis or healthy black controls, AASK-N samples had lower amounts of six markers. Four markers (albumin, ß-2-microglobulin, cystatin C, and osteopontin) were undetectable in most AASK-N samples. Examination by SDS-PAGE followed by protein staining revealed protein profiles indicative of severe protein degradation in 34 of 37 AASK-N urine samples. Treatment of lupus nephritis urine samples with 0.5% acetic acid produced the same protein degradation profile as that of AASK-N urine. We conclude that the increased NAP in AASK-N is an artifact of acetic acid-mediated degradation of albumin. The AASK-N repository urine samples have been compromised by the acetic acid preservative.

BP Control and Long-Term Risk of ESRD and Mortality.

We recently showed an association between strict BP control and lower mortality risk during two decades of follow-up of prior participants in the Modification of Diet in Renal Disease (MDRD) trial. Here, we determined the risk of ESRD and mortality during extended follow-up of the African American Study of Kidney Disease and Hypertension (AASK) trial. We linked 1067 former AASK participants with CKD previously randomized to strict or usual BP control (mean arterial pressure ≤92 mmHg or 102-107 mmHg, respectively) to the US Renal Data System and Social Security Death Index; 397 patients had ESRD and 475 deaths occurred during a median follow-up of 14.4 years from 1995 to 2012. Compared with the usual BP arm, the strict BP arm had unadjusted and adjusted relative risks of ESRD of 0.92 (95% confidence interval [95% CI], 0.75 to 1.12) and 0.95 (95% CI, 0.78 to 1.16; P=0.64), respectively, and unadjusted and adjusted relative risks of death of 0.92 (95% CI, 0.77 to 1.10) and 0.81 (95% CI, 0.68 to 0.98; P=0.03), respectively. In meta-analyses of individual-level data from the MDRD and the AASK trials, unadjusted relative risk of ESRD was 0.88 (95% CI, 0.78 to 1.00) and unadjusted relative risk of death was 0.87 (95% CI, 0.76 to 0.99) for strict versus usual BP arms. Our findings suggest that, during long-term follow-up, strict BP control does not delay the onset of ESRD but may reduce the relative risk of death in CKD.

Revisiting medullary tophi: a link between uric acid and progressive chronic kidney disease?

BACKGROUND: It is well-established from autopsy studies that gouty tophi can form in the kidney, particularly in the renal medulla. Recently hyperuricemia has been identified as a risk factor for progression of chronic kidney disease (CKD). Because each collecting duct serves more than 2,000 nephrons, we postulated that obstruction or disruption of collecting ducts by medullary tophi may explain, at least in part, the association between hyperuricemia and progressive CKD. This work was done to determine the prevalence of medullary tophi in CKD patients. METHODS: We queried our nephropathology database over the last 10 years for native kidney biopsies that had medullary tophi. The presence or absence of CKD and uric acid levels around the time of biopsy were determined by chart review. RESULTS: Predominant medullary tissue was reported in 796 of 7,409 total biopsies, and 572 of these were from patients with established CKD. Medullary tophi were seen in 36 patients, 35 of whom had CKD, suggesting a minimum prevalence of tophi in CKD and no-CKD of 6.11 and 0.45%, respectively Medullary tophi occurred with and without hyperuricemia or a history of gout. CONCLUSION: Medullary tophi appear to be far more likely to occur in CKD compared to no-CKD patients. This cross-sectional study cannot determine whether medullary tophi are a cause or consequence of CKD. However, given their location and bulk, it is possible that medullary tophi contribute to progression of established CKD by causing upstream nephron damage.

Staphylococcus-related glomerulonephritis and poststreptococcal glomerulonephritis: why defining "post" is important in understanding and treating infection-related glomerulonephritis.

A spate of recent publications describes a newly recognized form of glomerulonephritis associated with active staphylococcal infection. The key kidney biopsy findings, glomerular immunoglobulin A (IgA) deposits dominant or codominant with IgG deposits, resemble those of IgA nephritis. Many authors describe this condition as "postinfectious" and have termed it "poststaphylococcal glomerulonephritis." However, viewed through the prism of poststreptococcal glomerulonephritis, the prefix "post" in poststaphylococcal glomerulonephritis is historically incorrect, illogical, and misleading with regard to choosing therapy. There are numerous reports describing the use of high-dose steroids to treat poststaphylococcal glomerulonephritis. The decision to use steroid therapy suggests that the treating physician believed that the dominant problem was a postinfectious glomerulonephritis, not the infection itself. Unfortunately, steroid therapy in staphylococcus-related glomerulonephritis can precipitate severe staphylococcal sepsis and even death and provides no observable benefits. Poststreptococcal glomerulonephritis is an authentic postinfectious glomerulonephritis; poststaphylococcal glomerulonephritis is not. Making this distinction is important from the perspective of history, pathogenesis, and clinical management.

Brodifacoum induces early hemoglobinuria and late hematuria in rats: novel rapid biomarkers of poisoning.

INTRODUCTION: Brodifacoum (BDF) is a superwarfarin that is used primarily as a rodenticide. There have been increasing numbers of reports of human cases of accidental or intentional BDF ingestion with high mortality rate. Its broad availability and high lethality suggest that BDF should be considered a potential chemical threat. Currently, there is no biomarker for early detection of BDF ingestion in humans; patients typically present with severe coagulopathy. Since we demonstrated earlier that warfarin can induce acute kidney injury with hematuria, we tested whether BDF would also lead to change in urinary biomarkers. MATERIAL AND METHODS: BDF was administered to Sprague Dawley rats via oral gavage. N-acetylcysteine (NAC) was given per os in drinking water 24 h prior to BDF. Urinalysis was performed at different times after BDF administration. Anticoagulation and serum creatinine levels were analyzed in the blood. RESULTS: We observed that within a few hours the animals developed BDF-dose-dependent transient hemoglobinuria, which ceased within 24 h. This was accompanied by a transient decrease in hematocrit, gross hemolysis and an increase in free hemoglobin in the serum. At later times, animals developed true hematuria with red blood cells in the urine, which was associated with BDF anticoagulation. NAC prevented early hemoglobinuria, but not late hematuria associated with BDF. CONCLUSIONS: We propose that transient early hemoglobinuria (associated with oxidative stress) with consecutive late hematuria (associated with anticoagulation) are novel biomarkers of BDF poisoning, and they can be used in clinical setting or in mass casualty with BDF to identify poisoned patients.

Nephrotic syndrome redux.

Redux: brought back, resurgent (Wikipedia free dictionary). This essay traces the history of the concepts that led to the usage of the term 'nephrotic syndrome' beginning ∼90 years ago. We then examined the various definitions used for this syndrome and modified them to conform to contemporary standards. Remarkably, only minor modifications were required. This analysis of a common clinical entity may be helpful in ensuring appropriate evaluation of patients suffering from nephrotic syndrome and nephrotic-range proteinuria.

A within-patient analysis for time-varying risk factors of CKD progression.

Recent data suggest that nonlinear GFR trajectories are common among patients with CKD, but the modifiable risk factors underlying these changes in CKD progression rate are unknown. Analyses relating baseline risk factors to subsequent GFR decline are suboptimal because these relationships often attenuate as follow-up time increases and these analyses do not account for temporal changes in risk factors. We identified 74 participants in the African American Study of Kidney Disease and Hypertension who had both a period of rapid GFR decline and an extended period of stability during a follow-up period of ≥12 years. We performed a within-patient comparison of time-varying risk factors measured during the periods of GFR decline and stability and identified several risk factors associated with faster GFR decline: more hospitalization episodes and hospitalization days per year; higher BP, serum phosphorus, and urine protein-to-creatinine ratio; lower serum albumin and urine sodium-to-potassium ratio; slower rate of decline of serum urea nitrogen, serum creatinine, serum uric acid, and serum phosphorus; and faster rate of decline of serum hematocrit and serum bicarbonate. By allowing each patient to serve as his or her own control, this novel, within-patient analytic approach holds considerable promise as a means to identify time-varying risk factors associated with stabilization of GFR or acceleration of GFR decline.

Warfarin-related nephropathy is the tip of the iceberg: direct thrombin inhibitor dabigatran induces glomerular hemorrhage with acute kidney injury in rats.

BACKGROUND: Excessive anticoagulation with warfarin can result in acute kidney injury (AKI) by causing glomerular hemorrhage and renal tubular obstruction by red blood cell (RBC) casts in some patients, especially in those with chronic kidney disease (CKD). This condition was described as warfarin-related nephropathy (WRN). Recent evidence suggests that WRN-like syndromes are not confined to anticoagulation with warfarin, but may be seen with other anticoagulants, such as dabigatran. The aim of this study was to investigate dabigatran effects on kidney function in an animal model of CKD and possible pathogenic mechanisms of AKI. METHODS: Control and 5/6 nephrectomy rats were treated with different doses of dabigatran and protease-activated receptor 1 (PAR-1) inhibitor SCH79797. RESULTS: Dabigatran resulted in changes in coagulation in rats similar to those in humans at 50 mg/kg/day. Dabigatran resulted in a dose-dependent increase in serum creatinine (Scr) and hematuria in both control and 5/6 nephrectomy rats. SCH79797 also increased Scr and hematuria, more prominent in animals with CKD. Morphologically, numerous RBC tubular casts were seen in 5/6 nephrectomy rats treated with either dabigatran or SCH79797 and only occasional RBC casts in control rats. CONCLUSIONS: Our data indicate that WRN represents part of a broader syndrome, anticoagulant-related nephropathy (ARN). ARN, at least partially, is mediated via PAR-1. Our findings suggest that not only CKD patients, but other patients as well, are at high risk of developing AKI if the therapeutic range of anticoagulation with dabigatran is exceeded. Close monitoring of kidney function in patients on dabigatran therapy is warranted.

Unexplained severe acute kidney injury with rapid recovery of kidney function 11 months later after the start of high-dose steroid therapy.

Our patient appears to represent a previously unrecognized variant of steroid-responsive minimal change disease (MCD)/focal and segmental glomerulosclerosis (FSGS) in which severe AKI developed even though the serum albumin was essentially normal and proteinuria was minimal. This would be a paradox because the AKI of MCD/FSGS is a manifestation of severe nephrotic syndrome. To explain this paradox, it is suggested that our patient is a rare variant of a phenomenon that is well documented in steroid-responsive MCD/FSGS, specifically, glomerular permeability to large molecules is increased (accounting for the proteinuria) but decreased to small molecules (accounting for the low glomerular filtration rate). Our patient promptly recovered kidney function on steroid therapy even though he had been oliguric and dialysis dependent for nearly 11 months. The possible pathophysiologic mechanisms for this remarkable presentation and outcome are discussed.

N-acetylcysteine ameliorates acute kidney injury but not glomerular hemorrhage in an animal model of warfarin-related nephropathy.

Warfarin-related nephropathy (WRN) occurs under conditions of overanticoagulation with warfarin. WRN is characterized by glomerular hemorrhage with occlusive tubular red blood cell (RBC) casts and acute kidney injury (AKI). Herein we test the hypothesis that oxidative stress plays a role in the AKI of WRN. 5/6 Nephrectomy rats were treated with either warfarin (0.04 mg·kg⁻¹·day⁻¹) alone or with four different doses of the antioxidant N-acetylcysteine (NAC). Also tested was the ability of our NAC regimen to mitigate AKI in a standard ischemia-reperfusion model in the rat. Warfarin resulted in a threefold or greater increase in prothrombin time in each experimental group. Serum creatinine (Scr) increased progressively in animals receiving only warfarin + vehicle. However, in animals receiving warfarin + NAC, the increase in Scr was lessened, starting at 40 mg·kg⁻¹·day⁻¹ NAC, and completely prevented at 80 mg·kg⁻¹·day⁻¹ NAC. NAC did not decrease hematuria or obstructive RBC casts, but mitigated acute tubular injury. Oxidative stress in the kidney was increased in animals with WRN and it was decreased by NAC. The NAC regimen used in the WRN model preserved kidney function in the ischemia-reperfusion model. Treatment with deferoxamine (iron chelator) did not affect WRN. No iron was detected in tubular epithelial cells. In conclusion, this work taken together with our previous works in WRN shows that glomerular hematuria is a necessary but not sufficient explanation for the AKI in WRN. The dominant mechanism of the AKI of WRN is tubular obstruction by RBC casts with increased oxidative stress in the kidney.

Intensive blood-pressure control in hypertensive chronic kidney disease.

BACKGROUND: In observational studies, the relationship between blood pressure and end-stage renal disease (ESRD) is direct and progressive. The burden of hypertension-related chronic kidney disease and ESRD is especially high among black patients. Yet few trials have tested whether intensive blood-pressure control retards the progression of chronic kidney disease among black patients. METHODS: We randomly assigned 1094 black patients with hypertensive chronic kidney disease to receive either intensive or standard blood-pressure control. After completing the trial phase, patients were invited to enroll in a cohort phase in which the blood-pressure target was less than 130/80 mm Hg. The primary clinical outcome in the cohort phase was the progression of chronic kidney disease, which was defined as a doubling of the serum creatinine level, a diagnosis of ESRD, or death. Follow-up ranged from 8.8 to 12.2 years. RESULTS: During the trial phase, the mean blood pressure was 130/78 mm Hg in the intensive-control group and 141/86 mm Hg in the standard-control group. During the cohort phase, corresponding mean blood pressures were 131/78 mm Hg and 134/78 mm Hg. In both phases, there was no significant between-group difference in the risk of the primary outcome (hazard ratio in the intensive-control group, 0.91; P=0.27). However, the effects differed according to the baseline level of proteinuria (P=0.02 for interaction), with a potential benefit in patients with a protein-to-creatinine ratio of more than 0.22 (hazard ratio, 0.73; P=0.01). CONCLUSIONS: In overall analyses, intensive blood-pressure control had no effect on kidney disease progression. However, there may be differential effects of intensive blood-pressure control in patients with and those without baseline proteinuria. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center on Minority Health and Health Disparities, and others.)