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Understanding normal aging of kidney function is pivotal to help distinguish individuals at particular risk for chronic kidney disease. Glomerular filtration rate (GFR) is typically estimated via serum creatinine (eGFRcrea) or cystatin C (eGFRcys). Since population-based age-group-specific reference values for eGFR and eGFR-decline are scarce, we aimed to provide such reference values from population-based data of a wide age range. In four German population-based cohorts (KORA-3, KORA-4, AugUR, DIACORE), participants underwent medical exams, interview, and blood draw up to five times within up to 25 years. We analyzed eGFRcrea and eGFRcys cross-sectionally and longitudinally (12,000 individuals, age 25-95 years). Cross-sectionally, we found age-group-specific eGFRcrea to decrease approximately linearly across the full age range, for eGFRcys up to the age of 60 years. Within age-groups, there was little difference by sex or diabetes status. Longitudinally, linear mixed models estimated an annual eGFRcrea decline of -0.80 [95% confidence interval -0.82, -0.77], -0.79 [-0.83, -0.76], and -1.20 mL/min/1.73m 2 [-1.33, -1.08] for the general population, "healthy" individuals, or individuals with diabetes, respectively. Reference values for eGFR using cross-sectional data were shown as percentile curves for "healthy" individuals and for individuals with diabetes. Reference values for eGFR-decline using longitudinal data were presented as 95% prediction intervals for "healthy" individuals and for individuals with diabetes, obesity, and/or albuminuria. Thus, our results can help clinicians to judge eGFR values in individuals seen in clinical practice according to their age and to understand the expected range of annual eGFR-decline based on their risk profile., (Copyright © 2024 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Current kidney perfusion protocols are not optimized for addressing the ex vivo physiological and metabolic needs of the kidney. Ex vivo normothermic perfusion may be utilized to distinguish high-risk kidneys to determine suitability for transplantation. Here, we assessed the association of tissue metabolic changes with changes in a kidney injury biomarker and functional parameters in eight deceased donor kidneys deemed unsuitable for transplantation during a 12-hour ex vivo normothermic perfusion. The kidneys were grouped into good and poor performers based on blood flow and urine output. The mean age of the deceased kidney donors was 43 years with an average cold ischemia time of 37 hours. Urine output and creatinine clearance progressively increased and peaked at six hours post-perfusion among good performers. Poor performers had 71 ng/ml greater (95% confidence interval 1.5, 140) urinary neutrophil gelatinase-associated lipocalin at six hours compared to good performers corresponding to peak functional differences. Organ performance was distinguished by tissue metabolic differences in branched chain amino acid metabolism and that their tissue levels negatively correlated with urine output among all kidneys at six hours. Tissue lipid profiling showed poor performers were highlighted by the accumulation of membrane structure components including glycerolipids and sphingolipids at early perfusion time points. Thus, we showed that six hours is needed for kidney function recovery during ex vivo normothermic perfusion and that branched chain amino acid metabolism may be a major determinant of organ function and resilience., (Copyright © 2024 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

People with human immunodeficiency virus (HIV) are at risk for chronic kidney disease (CKD) due to HIV and antiretroviral therapy (ART) nephrotoxicity. Immediate ART initiation reduces mortality and is now the standard of care, but the long-term impact of prolonged ART exposure on CKD is unknown. To evaluate this, the Strategic Timing of Antiretroviral Treatment (START) trial randomized 4,684 ART-naïve adults with CD4 cell count under 500 cells/mm 3 to immediate versus deferred ART. We previously reported a small but statistically significantly greater decline in estimated glomerular filtration rate (eGFR) over a median of 2.1 years in participants randomized to deferred versus immediate ART. Here, we compare the incidence of CKD events and changes in eGFR and urine albumin/creatinine ratio (UACR) in participants randomized to immediate versus deferred ART during extended follow-up. Over a median of 9.3 years, eight participants experienced kidney failure or kidney-related death, three in the immediate and five in the deferred ART arms, respectively. Over a median of five years of more comprehensive follow-up, the annual rate of eGFR decline was 1.19 mL/min/1.73m 2 /year, with no significant difference between treatment arms (difference deferred - immediate arm 0.055; 95% confidence interval -0.106, 0.217 mL/min/1.73m 2 ). Results were similar in models adjusted for baseline covariates associated with CKD, including UACR and APOL1 genotype. Similarly, there was no significant difference between treatment arms in incidence of confirmed UACR 30 mg/g or more (odds ratio 1.13; 95% confidence interval 0.85, 1.51). Thus, our findings provide the most definitive evidence to date in support of the long-term safety of early ART with respect to kidney health., (Copyright © 2024 International Society of Nephrology. All rights reserved.)

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) reduce the risk for several adverse outcomes among patients with diabetic kidney disease. Yet, optimal timing for SGLT2i after acute kidney injury (AKI) is uncertain, as are the providers responsible for post-AKI SGLT2i initiation. Using a retrospective cohort of United States Veterans with diabetes mellitus type 2 and proteinuria, we examined encounters by provider specialty before SGLT2i initiation and subsequent all-cause mortality after hospitalization with AKI, defined by a 50% or more rise in serum creatinine. Covariates included recovery, defined by return to a 110% or less of baseline creatinine, and time since AKI hospitalization. Among 21,330 eligible Veterans, 7,798 died (37%) and 6,562 received a SGLT2i (31%) over median follow-up of 2.1 years. Post-AKI SGLT2i use was associated with lower mortality risk [adjusted hazard ratio 0.63 (95% confidence interval 0.58-0.68)]. Compared with neither SGLT2i use nor recovery, mortality risk was similar with recovery without SGLT2i use [0.97 (0.91-1.02)] but was lower without recovery prior to SGLT2i use [0.62 (0.55-0.71)] and with SGLT2i use after recovery [0.60 (0.54-0.67)]. Finally, the effect of SGLT2i was stable over time (P for time-interaction 0.19). Thus, we observed reduced mortality with SGLT2i use after AKI among Veterans with diabetic kidney disease whether started earlier or later or before or after observed recovery. Hence, patients with diabetic kidney disease who receive a SGLT2i earlier after AKI experience no significant harm impacting mortality and experience a lower mortality risk than those who do not., (Copyright © 2024 International Society of Nephrology. All rights reserved.)

Atacicept is a first-in-class, dual anti-B-cell Activation Factor-A Proliferation-Inducing Ligand fusion protein in clinical evaluation for treatment of IgA nephropathy. To compare efficacy and safety of atacicept versus placebo in patients with IgAN, this randomized, double-blind, placebo-controlled phase 2b clinical trial ORIGIN enrolled 116 individuals with biopsy-proven IgA nephropathy. Participants were randomized to atacicept 150, 75, or 25 mg versus placebo once weekly for up to 36 weeks. Primary and key secondary endpoints were changes in urine protein creatinine ratio based on 24-hour urine collection at weeks 24 and 36, respectively, in the combined atacicept 150 mg and 75 mg group versus placebo. The primary endpoint was met at week 24 as the mean urine protein creatinine ratio was reduced from baseline by 31% in the combined atacicept group versus 8% with placebo, resulting in a significant 25% reduction with atacicept versus placebo. At week 36, the key secondary endpoint was met as the mean urine protein creatinine ratio reduced from baseline by 34% in the combined atacicept group versus a 2% increase with placebo, resulting in a significant 35% reduction with atacicept versus placebo. The reduction in proteinuria was accompanied by stabilization in endpoint eGFR with atacicept compared to a decline with placebo at week 36, resulting in significant between-group geometric mean difference of 11%, approximating an absolute difference of 5.7 mL/min/1.73m 2 . Endpoint galactose deficient IgA1 levels significantly decreased from baseline by 60% versus placebo. The safety profile of atacicept was like placebo. Thus, our results provide evidence to support a pivotal, phase 3 study of atacicept in IgA nephropathy., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Hepatitis C virus (HCV) infection is common and can accelerate chronic kidney disease (CKD) progression. Direct-acting antiviral (DAA) therapies against hepatitis C have consistently shown rates of sustained viral remission. However, the effect on kidney function is unknown. In a retrospective observational cohort study of HCV-infected patients receiving DAA therapies from 2013 to 2017, the slopes of estimated glomerular filtration rate (eGFR) decline were compared in the three years before DAA therapy to the slope after therapy. Pre- and post-treatment albuminuria values were also compared. In all, 1,178 patients were included; mean age of 56, 64% male, 71% white, 21% were diabetic, and 42% with cirrhosis. In patients with eGFR less than 60ml/min per 1.73m 2 , the annual decline in eGFR in the three years prior to treatment was -5.98 ml/min per year (95% confidence interval -7.30 to -4.67) and improved to -1.32 ml/min per year (95% confidence interval -4.50 to 1.88) after DAA therapy. In patients with eGFR greater than 60ml/min per 1.73m 2 the annual decline in eGFR in the three years prior to treatment was -1.43 ml/min per year (95% confidence interval -1.78 to -1.08) and after DAA therapy was -2.32 ml/min per year (95% confidence interval -3.36 to -1.03). Albuminuria improved significantly in patients without diabetes, but not in those with diabetes. Predictors of eGFR improvement included having CKD at baseline and being non-diabetic. Events of acute kidney injury were rare, occurring in 29 patients, and unrelated to antiviral therapy in 76% of cases. Thus, DAA therapy for HCVs infection may slow CKD progression., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Glomerular filtration rate (GFR) is the best index for kidney function; however, the applicability of GFR estimating equations in sub-Saharan African populations remains unclear. In a cross-sectional study of adults living in Kinshasa, Democratic Republic of Congo (n=210) and Abidjan, Ivory Coast (n=284), we evaluated the performance of creatinine and cystatin C-based equations using plasma clearance of iohexol as the reference standard. The race coefficient did not improve the performance of creatinine-based GFR estimates; in fact, both the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology (CKD-EPI) equations performed better without the race coefficient in participants with GFR ≥60 mL/min/1.73m 2 . The CKD-EPI and Full Age Spectrum (FAS) equations were unbiased and had similar precision (SD of 17.9 versus 19 mL/min/1.73 m 2 ) and accuracy within 30% (P30, 86.7% versus 87.4%) in participants with GFR ≥60 mL/min/1.73m 2 . Both equations performed poorly in the subgroup with measured GFR < 60 mL/min/1.73m 2 (n=80), but the FAS equation had smaller bias (-4.8 mL/min/1.73m 2 versus -7.7 mL/min/1.73m 2 for CKD-EPI) and higher P30 (56.3% versus 31.3% for CKD-EPI). The corresponding equations including cystatin C alone or in combination with creatinine had similar performance. In a sub-Saharan African population, adjustment for race did not improve the performance of GFR estimating equations. The creatinine-based FAS and CKD-EPI equations performed reasonably well and were comparable when GFR was ≥ 60 mL/min/1.73m 2 . Cystatin C did not improve performance. The FAS equation may be preferable when GFR is < 60 mL/min/1.73m 2 , but this should be confirmed in larger studies., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The current Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend the use of the bedside creatinine-based Chronic Kidney Disease in Children (CKiD) equation to estimate glomerular filtration rate (GFR) in children and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation in adults. However, this approach causes implausible changes in estimated GFR (eGFR) at the transition from pediatric to adult care. We investigated the performance of the KDIGO strategy and various creatinine-based eGFR equations in a cross-sectional dataset of 5,764 subjects (age 10-30 years), using directly measured GFR (mGFR) as reference. We also evaluated longitudinal GFR slopes in 136 subjects who transitioned to adult care. Implausible changes in eGFR resulted from the large overestimation (bias=+21 mL/min/1.73m 2 ) and poor precision of the CKD-EPI equation in the 18-20 year age group, compared to CKiD in the 16-18 year age group (bias=-2.7 mL/min/1.73m 2 ), resulting in a mean change of 23 mL/min/1.73m 2 at the transition to adult care. Averaging the CKiD and CKD-EPI estimates in young adults only partially mitigated this issue. The Full Age Spectrum equation (with and without height), the Lund-Malmö Revised equation, and an age-dependent weighted average of CKiD and CKD-EPI resulted in much smaller changes in eGFR at the transition (change of 0.6, -2.1, -0.9 and -1.8 mL/min/1.73m 2 , respectively). The longitudinal analysis revealed a significant difference in average GFR slope between mGFR and the KDIGO strategy (-2.2 vs. +2.9 mL/min/1.73 m 2 /year), which was not observed with the other approaches. These results suggest that the KDIGO recommendation for GFR estimation at the pediatric-adult care transition should be revisited., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

While direct measurements of glomerular filtration rate (GFR) provide the most accurate evaluation of pre-donation kidney function, guidelines do not systematically require the use of a reference method. We evaluated whether and to what extent relying upon creatinine-based estimating equations (eGFR) rather than direct measurement of GFR (mGFR) alters the selection of potential living donors. We compared the impact of 4 equations (the MDRD study equation, the CKD-EPI equation, the revised Lund-Malmö equation, and the full age spectrum [FAS] equation) on the evaluation of 2733 potential donors with GFR measured by reference methods. We also considered the impact of using either absolute or age-adapted GFR thresholds. The CKD-EPI and FAS equations had the best performances (P10 of 50.6% and 47.8%; P30 of 94.4% and 93.1%, respectively) and led to the lowest proportion of improperly evaluated candidates. Misclassification was more frequent when GFR adequacy was defined as an absolute threshold of 90 ml/min/1.73m 2 as compared to an age-adapted definition (26% and 5%, respectively). Interpretation of eGFR according to an absolute threshold of 90 ml/min/1.73m 2 identified 1804 candidates eligible to donate, compared to 2648 when mGFR was interpreted with age-adapted thresholds. We conclude that creatinine-based estimates cannot substitute for direct GFR measurement to evaluate candidates for kidney donation. When reference methods for direct GFR measurement are not available, our data suggest that a strategy based on age-adapted eGFR values estimated with either the CKD-EPI or FAS equation should be preferred., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The 2012 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline classifies acute kidney injury (AKI) into 3 stages defined by serum creatinine elevation or urine output decline. We evaluated the potential impact of further categorizing AKI stage 1 into two stages based on serum creatinine criteria, with a focus on how the resulting 4-stage classification would affect the association of AKI stages with clinical outcomes. We defined AKI stage 1a as an absolute increase in serum creatinine of 0.3 mg/dl within 48 hours and stage 1b as a 50% relative increase in serum creatinine within 7 days. We screened all admissions to 5 hospitals from 2012 to 2014 using standardized inclusion and exclusion criteria and included 81,651 admissions in this retrospective cohort study. The incidence of in-hospital AKI was 7.5% for stage 1a, 4.9% for stage 1b, 1.5% for stage 2, and 0.9% for stage 3. Length of stay following the first incidence of AKI was 3.9 days for stage 1a, 6.2 days for stage 1b, 8.8 days for stage 2, and 12.0 days for stage 3. Compared to patients with no AKI, the odds of in-hospital mortality were progressively higher for patients with higher AKI stages (odds ratio 4.3 for patients with stage 1a, 10.9 for stage 1b, 40.6 for stage 2, and 60.0 for stage 3 AKI). Patients with AKI stages 1a and 1b experienced clinically meaningful and statistically significant differences in length of stay and mortality. This study suggests that a modified 4-stage version of the KDIGO AKI classification may provide additional prognostic information., (Copyright © 2019 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Renal tissue hypoxia is a final pathway in the development and progression of chronic kidney disease (CKD), but whether renal oxygenation predicts renal function decline in humans has not been proven. Therefore, we performed a prospective study and measured renal tissue oxygenation by blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) in 112 patients with CKD, 47 with hypertension without CKD, and 24 healthy control individuals. Images were analyzed with the twelve-layer concentric objects method that divided the renal parenchyma in 12 layers of equal thickness and reports the mean R2* value of each layer (a high R2* corresponds to low oxygenation), along with the change in R2* between layers called the R2* slope. Serum creatinine values were collected to calculate the yearly change in estimated glomerular function rate (MDRD eGFR). Follow up was three years. The change in eGFR in CKD, hypertensive and control individuals was -2.0, 0.5 and -0.2 ml/min/1.73m 2 /year, respectively. In multivariable regression analysis adjusted for age, sex, diabetes, RAS-blockers, eGFR, and proteinuria the yearly eGFR change correlated negatively with baseline 24 hour proteinuria and the mean R2* value of the cortical layers, and positively with the R2* slope, but not with the other covariates. Patients with CKD and high outer R2* or a flat R2* slope were three times more likely to develop an adverse renal outcome (renal replacement therapy or over a 30% increase in serum creatinine). Thus, low cortical oxygenation is an independent predictor of renal function decline. This finding should stimulate studies exploring the therapeutic impact of improving renal oxygenation on renal disease progression., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Mesenchymal stem cells (MSCs) are effective for the management of experimental ischemia-reperfusion acute kidney injury (IRI-AKI). Immune modulation is one of the important mechanisms of MSCs treatment. Interleukin-17A (IL-17A) pretreated MSCs are more immunosuppressive with minimal changes in immunogenicity in vitro. Here, we demonstrated that administration of IL-17A-pretreated MSCs resulted in significantly lower acute tubular necrosis scores, serum creatinine, and BUN of mice with IRI-AKI, compared with the administration of MSCs. Of the co-cultured splenocytes, IL-17A-pretreated MSCs significantly increased the percentages of CD4 + Foxp3 + Tregs and decreased concanavalin A-induced T cell proliferation. Furthermore, mice with IRI-AKI that underwent IL-17A-pretreated MSC therapy had significantly lower serum IL-6, TNF-α, and IFN-γ levels, a higher serum IL-10 level, and higher spleen and kidney Treg percentages than the mice that underwent MSCs treatment. Additionally, the depletion of Tregs by PC61 (anti-CD25 antibody) reversed the enhanced treatment efficacy of the IL-17A-pretreatedMSCs on mice with IRI-AKI. Additionally, IL-17A upregulated COX-2 expression and increased PGE2 production. The blockage of COX-2 by celecoxib reversed the benefit of IL-pretreated 17A-MSCs on the serum PGE2 concentration, spleen and kidney Tregs percentages, serum creatinine and BUN levels, renal acute tubular necrosis scores, and serum IL-6, TNF-α, IFN-γ, and IL-10 levels of IRI-pretreated mice with AKI, compared with MSCs. Thus, our results suggest that IL-17A pretreatment enhances the efficacy of MSCs on mice with IRI-AKI by increasing the Treg percentages through the COX-2/PGE2 pathway., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The urate oxidase (Uox) gene encodes uricase that in the rodent liver degrades uric acid into allantoin, forming an obstacle for establishing stable mouse models of hyperuricemia. The loss of uricase in humans during primate evolution causes their vulnerability to hyperuricemia. Thus, we generated a Uox-knockout mouse model on a pure C57BL/6J background using the transcription activator-like effector nuclease (TALEN) technique. These Uox-knockout mice spontaneously developed hyperuricemia (over 420 μmol/l) with about 40% survival up to 62 weeks. Renal dysfunction (elevated serum creatinine and blood urea nitrogen) and glomerular/tubular lesions were observed in these Uox-knockout mice. Male Uox-knockout mice developed glycol-metabolic disorders associated with compromised insulin secretion and elevated vulnerability to streptozotocin-induced diabetes, whereas female mice developed hypertension accompanied by aberrant lipo-metabolism. Urate-lowering drugs reduced serum uric acid and improved hyperuricemia-induced disorders. Thus, uricase knockout provides a suitable mouse model to investigate hyperuricemia and associated disorders mimicking the human condition, suggesting that hyperuricemia has a causal role in the development of metabolic disorders and hypertension., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The transcription factor MafB is essential for development of the parathyroid glands, the expression of which persists after morphogenesis and in adult parathyroid glands. However, the function of MafB in adult parathyroid tissue is unclear. To investigate this, we induced chronic kidney disease (CKD) in wild-type and MafB heterozygote (MafB+/-) mice by feeding them an adenine-supplemented diet, leading to secondary hyperparathyroidism. The elevated serum creatinine and blood urea nitrogen levels in heterozygous and wild-type mice fed the adenine-supplemented diet were similar. Interestingly, secondary hyperparathyroidism, characterized by serum parathyroid hormone elevation and enlargement of parathyroid glands, was suppressed in MafB+/- mice fed the adenine-supplemented diet compared to similarly fed wild-type littermates. Quantitative RT-PCR and immunohistochemical analyses showed that the increased expression of parathyroid hormone and cyclin D2 in mice with CKD was suppressed in the parathyroid glands of heterozygous CKD mice. A reporter assay indicated that MafB directly regulated parathyroid hormone and cyclin D2 expression. To exclude an effect of a developmental anomaly in MafB+/- mice, we analyzed MafB tamoxifen-induced global knockout mice. Hypocalcemia-stimulated parathyroid hormone secretion was significantly impaired in MafB knockout mice. RNA-sequencing analysis indicated PTH, Gata3 and Gcm2 depletion in the parathyroid glands of MafB knockout mice. Thus, MafB appears to play an important role in secondary hyperparathyroidism by regulation of parathyroid hormone and cyclin D2 expression. Hence, MafB may represent a new therapeutic target in secondary hyperparathyroidism., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Acute kidney injury (AKI) is a frequent complication in patients with ST-elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention. However, the pathophysiology of AKI in this setting is complex and goes beyond the administration of contrast media. Studies assessing the impact of infarct characteristics on AKI are currently lacking. Therefore, we investigated the association of AKI with myocardial as well as microvascular injury in an initial total of 361 consecutive STEMI patients treated by primary percutaneous coronary intervention. Of these, 318 patients were included in final analysis. Serum creatinine was measured on admission as well as 24, 48, and 72 hours thereafter with AKI defined as an increase in serum creatinine of 0.3 mg/dl or more. Cardiac magnetic resonance (CMR) scans were performed in the first week after infarction, with microvascular injury visualized by late gadolinium enhancement CMR defined as any region of hypoenhancement within the hyperenhanced area of infarction. Sixteen patients developed AKI. They showed significantly lower left ventricular ejection fraction (45[interquartile range 40-52]% vs. 54[47-59]%), larger infarct size (21[15-35]% vs. 12[7-22]%) of left ventricular myocardial mass, and more frequent microvascular injury (81 vs. 46%) than those free of AKI. Meaningfully, in multivariate analysis including all CMR data, microvascular injury was the sole independent predictor of AKI (odds ratio 6.74, 95% confidence interval of 1.49-30.43). Thus, among revascularized STEMI patients, the presence of microvascular injury assessed by CMR was independently associated with an increased risk of AKI. This suggests a potential pathophysiological link between cardiac microvascular disease and renal injury following STEMI., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Cardiac surgery associated-acute kidney injury (CS-AKI) occurs in 30-50% of patients undergoing surgery for congenital heart disease. Here we determine if CS-AKI is associated with chronic kidney disease (CKD) in patients with congenital heart disease. Using Danish regional population-based registries, our cohort study included patients with congenital heart disease born between 1990-2010 with first cardiac surgery between 2005 and 2010 (under 15 years of age). Utilizing in- and out-patient laboratory serum creatinine data, we identified individuals fulfilling KDIGO stages of AKI within 5 days of cardiac surgery. A unique personal identifier enabled unambiguous data linkage and virtually complete follow-up. The cumulative incidences of CKD stages 2-5 according to presence of CS-AKI were computed utilizing serum creatinine values and Pottel's formula. Using Cox regression, the corresponding hazard ratios were computed, adjusting for sex, age at first cardiac surgery, calendar period of surgery, and congenital heart disease severity. Of 382 patients with congenital heart disease undergoing cardiac surgery, 127 experienced CS-AKI within 5 days of surgery. Median follow-up was 4.9 years. The five-year cumulative incidence of CKD for patients with CS-AKI was 12% (95% confidence interval 7%-20%), significantly higher than the 3% (1%-5%) for those without CS-AKI with a significant adjusted hazard ratio of 3.8 (1.4-10.4). Thus, CS-AKI in patients with congenital heart disease is common and is associated with an increased risk for CKD., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Extensive structural damage within the kidney must be present before serum creatinine increases. However, a subclinical phase of chronic kidney disease (CKD) usually goes undetected. Here we tested whether experimental subclinical CKD would modify functional and damage biomarker profiles of acute kidney injury (AKI). Subclinical CKD was induced in rats by adenine or aristolochic acid models but without increasing serum creatinine. After prolonged recovery (three to six weeks), AKI was induced with a subnephrotoxic dose of cisplatin. Urinary levels of kidney injury molecule-1 (KIM-1), cytochrome C, monocyte chemotactic protein-1 (MCP-1), clusterin, and interleukin-18 increased during CKD induction, without an increase in serum creatinine. After AKI in adenine-induced CKD, serum creatinine increased more rapidly, while increased urinary KIM-1, clusterin, and MCP-1 were delayed and reduced. Increased serum creatinine and biomarker excretion were associated with diffuse tubulointerstitial injury in the outer stripe of outer medulla coupled with over 50% cortical damage. Following AKI in aristolochic acid-induced CKD, increased serum creatinine, urinary KIM-1, clusterin, MCP-1, cytochrome C, and interleukin-18 concentrations and excretion were greater at day 21 than day 42 and inversely correlated with cortical injury. Subclinical CKD modified functional and damage biomarker profiles in diametrically opposite ways. Functional biomarker profiles were more sensitive, while damage biomarker diagnostic thresholds and increases were diminished and delayed. Damage biomarker concentrations and excretion were inversely linked to the extent of prior cortical damage. Thus, thresholds for AKI biomarkers may need to be lower or sampling delayed in the known presence of CKD., (Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.)

A prospective national cohort study was undertaken to collect data on all cases of pediatric (under 18 yrs of age) acute kidney injury (AKI) identified by a biochemistry-based electronic alert using the Welsh National electronic AKI reporting system. Herein we describe the utility and limitation of using this modification of the KDIGO creatinine-based system data set to characterize pediatric AKI. Of 1,343 incident episodes over a 30-month period, 34.5% occurred in neonates of which 83.8% were AKI stage 1. Neonatal 30-day mortality was 4.1%, with 73.3% of this being accounted for by patients treated in an Intensive Care Unit. In the non-neonatal group, 76.1% were AKI stage 1. Hospital-acquired AKI accounted for 40.1% of episodes while community-acquired AKI represented 29.4% of cases within which 33.9% were admitted to hospital and 30.5% of cases were unclassified. Non-neonatal 30-day mortality was 1.2%, with half of this accounted for by patients treated in the Intensive Care Unit. Nonrecovery of renal function at 30 days occurred in 28% and was significantly higher in patients not admitted to hospital (45% vs. 20%). The reported incidence of AKI in children was far greater than previously reported in studies reliant on clinical identification of adult AKI or hospital coding data. Mortality was highest in neonates and driven by those in the Intensive Care Unit. Nonrecovery of renal function and persistent renal impairment was more common in non-neonates and was especially high in patients with community-acquired AKI who were not hospitalized., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

In the absence of uncontrolled hypertension or renal insufficiency, many consider the perinatal outcomes in pregnant women with nephrotic syndrome to be good. To further investigate this we performed a retrospective chart review of women with biopsy-proven nephrotic syndrome due to primary glomerular disease during pregnancy at a single tertiary center. Our review determined characteristics, presentation, management, pathologic diagnoses, and associated renal and maternal-fetal outcomes of 19 individuals with 26 pregnancies and 26 offspring. The mean age was 27.6 years, the mean gestational age at the presentation of nephrotic syndrome was 18.6 weeks, the mean creatinine was 0.85 mg/dL, mean serum albumin was 1.98 g/dL, and the mean proteinuria was 8.33 g/24 hours. The mean cardiac output was 8.6 L/minute, which was elevated compared to normal pregnancy. A kidney biopsy was performed during pregnancy in 8 individuals (median gestational age at time of biopsy was 21 weeks), changing management in six. Of the 26 pregnancies, maternal complications included preeclampsia in seven, acute kidney injury in six, premature rupture of membranes in two, and cellulitis in three. The mean age of gestation at delivery was 35.5 weeks. Fetal complications included low birth weight (under 2,500 g) in 14, intra-uterine growth restriction in three, and neonatal intensive care unit admission in eight. Thus, pregnant women with nephrotic syndrome are at high risk for developing both maternal and fetal complications, even in the absence of significant renal impairment or uncontrolled hypertension at the time of presentation of nephrotic syndrome., (Copyright © 2017 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Chronic kidney disease (CKD) affects up to 6% of women of childbearing age in high income countries, and is estimated to affect 3% of pregnant women. Advanced renal dysfunction, proteinuria, hypertension, and poorly controlled underlying primary renal disease are all significant risks for adverse maternal, fetal, and renal outcomes. In order to achieve the best outcomes, it is therefore of paramount importance that these pregnancies are planned, where possible, to allow the opportunity to counsel women and their partners in advance and to optimize these risks. These pregnancies should be deemed high risk and they require close antenatal monitoring from an expert multidisciplinary team. We discuss the effect of pregnancy on CKD, and also current guidelines and literature with specific reference to transplantation, autoimmune disease, and medication use in pregnancy. We also discuss the benefits of prepregnancy counseling and give practical recommendations to advise pregnant women with renal disease., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Deletion of cyclooxygenase-2 (COX-2) causes impairment of postnatal kidney development. Here we tested whether the renin angiotensin system contributes to COX-2-dependent nephrogenesis in mice after birth and whether a rescue of impaired renal development and function in COX-2 -/- mice was achievable. Plasma renin concentration in mouse pups showed a birth peak and a second peak around day P8 during the first 10 days post birth. Administration of the angiotensin II receptor AT1 antagonist telmisartan from day P1 to P3 did not result in cortical damage. However, telmisartan treatment from day P3 to P8, the critical time frame of renal COX-2 expression, led to hypoplastic glomeruli, a thinned subcapsular cortex and maturational arrest of superficial glomeruli quite similar to that observed in COX-2 -/- mice. In contrast, AT2 receptor antagonist PD123319 was without any effect on renal development. Inhibition of the renin angiotensin system by aliskiren and enalapril caused similar glomerular defects as telmisartan. Administration of the AT1 receptor agonist L162313 to COX-2 -/- pups improved kidney growth, ameliorated renal defects, but had no beneficial effect on reduced cortical mass. L162313 rescued impaired renal function by reducing serum urea and creatinine and mitigated pathologic albumin excretion. Moreover, glomerulosclerosis in the kidneys of COX-2 -/- mice was reduced. Thus, angiotensin II-AT1-receptor signaling is necessary for COX-2-dependent normal postnatal nephrogenesis and maturation., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

High blood pressure is a common cause of chronic kidney disease. Because CD40, a member of the tumor necrosis factor receptor family, has been linked to the progression of kidney disease in ischemic nephropathy, we studied the role of Cd40 in the development of hypertensive renal disease. The Cd40 gene was mutated in the Dahl S genetically hypertensive rat with renal disease by targeted-gene disruption using zinc-finger nuclease technology. These rats were then given low (0.3%) and high (2%) salt diets and compared. The resultant Cd40 mutants had significantly reduced levels of both urinary protein excretion (41.8 ± 3.1 mg/24 h vs. 103.7 ± 4.3 mg/24 h) and plasma creatinine (0.36 ± 0.05 mg/dl vs. 1.15 ± 0.19 mg/dl), with significantly higher creatinine clearance compared with the control S rats (3.04 ± 0.48 ml/min vs. 0.93 ± 0.15 ml/min), indicating renoprotection was conferred by mutation of the Cd40 locus. Furthermore, the Cd40 mutants had a significant attenuation in renal fibrosis, which persisted on the high salt diet. However, there was no difference in systolic blood pressure between the control and Cd40 mutant rats. Thus, these data serve as the first evidence for a direct link between Cd40 and hypertensive nephropathy. Hence, renal fibrosis is one of the underlying mechanisms by which Cd40 plays a crucial role in the development of hypertensive renal disease., Competing Interests: All authors declared no competing interests., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Scarce and conflicting evidence exists on whether clopidogrel is effective and whether dual antiplatelet treatment (DAPT) is safe in patients with acute coronary syndrome and chronic kidney disease (CKD). To study this, we performed an observational, prospective, multicenter cohort study of 36,001 patients of the SWEDEHEART registry. The exposure was DAPT prolonged after 3 months versus DAPT stopped at 3 months in consecutive patients with acute coronary syndrome and known serum creatinine. DAPT duration with clopidogrel and aspirin was assessed by dispensed tablets. CKD stages were classified according to estimated glomerular filtration rate (eGFR). Study outcomes were 1) the composite of death, myocardial infarction, or ischemic stroke; 2) bleeding; or 3) the aggregate of these two outcomes within day 111 and 365 from discharge. A longer DAPT duration, as compared with 3-month DAPT, was associated with lower hazard ratios for outcome one in each CKD stratum (eGFR over 60, adjusted hazard ratio [95% confidence interval] 0.76 [0.67-0.85]; eGFR 60 and less, 0.84 [0.73-0.96], of which eGFR between 45 and 60, 0.85 [0.70-1.05], eGFR between 30 and 45, 0.78 [0.62-0.97]; eGFR 30 and less ml/min/1.73 m 2 , 0.93 [0.70-1.24]. Bleeding (outcome 2) was in general more common in the longer DAPT group of each aforementioned CKD stratum. Aggregated outcome analysis (outcome 3) similarly favored longer DAPT in each stratum. There was no interaction between DAPT duration and CKD strata for any of the study outcomes. Thus, a prolonged as compared with three-month DAPT was similarly associated with a lower risk of death, stroke, or reinfarction regardless of underlying CKD., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The incidence of cardiovascular disease (CVD) is higher in patients with chronic kidney disease (CKD) than in the general population, and the risk of CVD increases with reductions in renal function. However, the incidence of CVD in Japanese patients with CKD has not been sufficiently investigated. To measure this we conducted the Chronic Kidney Disease Japan Cohort (CKD-JAC) Study over four years in 2,966 Japanese patients with CKD to examine the incidence of CVD and all-cause death. These patients had an estimated glomerular filtration rate (eGFR) of 10-59 ml/min/1.73 m 2 , were under nephrologist care, and pooled from 17 medical institutions in Japan. At the median follow-up of 3.9 years, 69 patients had died, 217 had cardiovascular events, and 514 started maintenance dialysis therapy. The incidences of cardiovascular events were 11.9, 19.1, 25.0, and 39.4 per 1,000 person-years at eGFRs of 45-59, 30-44, 15-29, and under 15 ml/min/1.73 m 2 , respectively. The adjusted Cox proportional hazards models showed that the risk of cardiovascular events increased as the eGFR decreased, with a significant difference only between CKD stage G5 (eGFR: under 15 ml/min/1.73 m 2 ) and CKD stage G3a (eGFR: 45-59 ml/min/1.73 m 2 ) (hazard ratio 3.16, 95% confidence interval 1.28 to 7.76). Thus, the risk of CVD and all-cause death was related to the decrease in eGFR, but not necessarily elevated in proportion to progression of the CKD stage in Japanese patients with predialysis CKD under a nephrologist's care., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Current guidelines for chronic kidney disease (CKD) recommend using albuminuria as well as estimated glomerular filtration rate (eGFR) to stage CKD. However, CKD progression is solely defined by change in eGFR with little regard to the risk implications of change in albuminuria. This is an observational study from the Stockholm CREAtinine Measurements (SCREAM) project, a health care utilization cohort from Stockholm, Sweden, with laboratory measures from 2006-2011 and follow-up through December 2012. Included were 31,732 individuals with two or more ambulatory urine albumin to creatinine ratio (ACR) tests. We assessed the association between change in ACR during a baseline period of 1, 2, or 3 years and end-stage renal disease (ESRD) or death. Using a 2-year baseline period, there were 378 ESRD events and 1712 deaths during a median of 3 years of follow-up. Compared to stable ACR, a 4-fold increase in ACR was associated with a 3.08-times (95% confidence interval 2.59 to 3.67) higher risk of ESRD while a 4-fold decrease in ACR was associated with a 0.34-times (0.26 to 0.45) lower risk of ESRD. Similar associations were found in people with and without diabetes mellitus, with and without hypertension, and also when adjusted for the change in eGFR during the same period. The association between change in ACR and mortality was weaker: ACR increase was associated with mortality, but the relationship was largely flat for ACR decline. Results were consistent for 1-, 2-, and 3-year ACR changes. Thus, changes in albuminuria are strongly and consistently associated with the risk of ESRD and death., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Vascular progenitor cells show promise for the treatment of microvasculature endothelial injury. We investigated the function of renal artery progenitor cells derived from radical nephrectomy patients, in animal models of acute ischemic and hyperperfusion injuries. Present in human adventitia, CD34positive/CD105negative cells were clonal and expressed transcription factors Sox2/Oct4 as well as surface markers CXCR4 (CD184)/KDR(CD309) consistent with endothelial progenitor cells. Termed renal artery-derived vascular progenitor cells (RAPC), injected cells were associated with decreased serum creatinine after ischemia/reperfusion, reduced albuminuria after hyperperfusion, and improved blood flow in both models. A small population of RAPC integrated with the renal microvasculature following either experimental injury. At a cellular level, RAPC promoted local endothelial migration in co-culture. Profiling of RAPC microRNA identified high levels of miRNA 218; also found at high levels in exosomes isolated from RAPC conditioned media after cell contact for 24 hours. After hydrogen peroxide-induced endothelial injury, RAPC exosomes harbored Robo-1 transcript; a gene known to be regulated by mir218. Such exosomes enhanced endothelial cell migration in culture in the absence of RAPC. Thus, our work shows the feasibility of pre-emptive pro-angiogenic progenitor cell procurement from a targeted patient population and potential therapeutic use in the form of autologous cell transplantation., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

The kallikrein-kinin system has been shown to be involved in the development of diabetic nephropathy, but specific mechanisms are not fully understood. Here, we determined the renal-protective role of exogenous pancreatic kallikrein in diabetic mice and studied potential mechanisms in db/db type 2 diabetic and streptozotocin-induced type 1 diabetic mice. After the onset of diabetes, mice were treated with either pancreatic kallikrein (db/db+kallikrein, streptozotocin+kallikrein) or saline (db/db+saline, streptozotocin+saline) for 16 weeks, while another group of streptozotocin-induced diabetic mice received the same treatment after onset of albuminuria (streptozotocin'+kallikrein, streptozotocin'+saline). Db/m littermates or wild type mice were used as non-diabetic controls. Pancreatic kallikrein had no effects on body weight, blood glucose and blood pressure, but significantly reduced albuminuria among all three groups. Pathological analysis showed that exogenous kallikrein decreased the thickness of the glomerular basement membrane, protected against the effacement of foot process, the loss of endothelial fenestrae, and prevented the loss of podocytes in diabetic mice. Renal fibrosis, inflammation and oxidative stress were reduced in kallikrein-treated mice compared to diabetic controls. The expression of kininogen1, tissue kallikrein, kinin B1 and B2 receptors were all increased in the kallikrein-treated compared to saline-treated mice. Thus, exogenous pancreatic kallikrein both prevented and ameliorated diabetic nephropathy, which may be mediated by activating the kallikrein-kinin system., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Apolipoprotein A-IV associated amyloidosis (AApoAIV amyloidosis) is a rare cause of amyloidosis with only a single reported case. Here we describe the clinical, biopsy, and mass spectrometry characteristics of 11 cases of renal AApoAIV amyloidosis encompassing 9 men and 2 women with a mean age at diagnosis of 63.5 years. Progressive chronic kidney disease (mean serum creatinine 2.9 mg/dl) was the most common cause for biopsy with proteinuria absent or minimal in all except one. Hematological and serological evaluation was negative in 9 patients, while 2 had a monoclonal gammopathy. The renal biopsy findings were striking and showed large amounts of eosinophilic Congo-red positive amyloid deposits restricted to the renal medulla with sparing of the renal cortex. In 6 cases, peritubular amyloid was noted in addition to the interstitial involvement. Immunofluorescence studies were negative for immunoglobulins. Electron microscopy showed nonbranching fibrils measuring 7 to 10 nm in diameter. Laser microdissection of the amyloid deposits followed by mass spectrometry showed large spectra number (a semiquantitative measure of abundance) for AApoAIV protein ranging from 49 to 169 (average 85), serum amyloid protein (average 19), and apolipoprotein E (average 48). Importantly, no peptides were detected for any other forms of known amyloidogenic precursor proteins. Thus, renal AApoAIV amyloidosis typically presents with progressive chronic kidney disease and histologically exhibits extensive medullary involvement with sparing of the cortex. The diagnosis is best established by mass spectrometry. Hence, a high degree of suspicion and examination of the renal medulla is required to make the diagnosis., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Immune checkpoint inhibitors (CPIs), monoclonal antibodies that target inhibitory receptors expressed on T cells, represent an emerging class of immunotherapy used in treating solid organ and hematologic malignancies. We describe the clinical and histologic features of 13 patients with CPI-induced acute kidney injury (AKI) who underwent kidney biopsy. Median time from initiation of a CPI to AKI was 91 (range, 21 to 245) days. Pyuria was present in 8 patients, and the median urine protein to creatinine ratio was 0.48 (range, 0.12 to 0.98) g/g. An extrarenal immune-related adverse event occurred prior to the onset of AKI in 7 patients. Median peak serum creatinine was 4.5 (interquartile range, 3.6-7.3) mg/dl with 4 patients requiring hemodialysis. The prevalent pathologic lesion was acute tubulointerstitial nephritis in 12 patients, with 3 having granulomatous features, and 1 thrombotic microangiopathy. Among the 12 patients with acute tubulointerstitial nephritis, 10 received treatment with glucocorticoids, resulting in complete or partial improvement in renal function in 2 and 7 patients, respectively. However, the 2 patients with acute tubulointerstitial nephritis not given glucocorticoids had no improvement in renal function. Thus, CPI-induced AKI is a new entity that presents with clinical and histologic features similar to other causes of drug-induced acute tubulointerstitial nephritis, though with a longer latency period. Glucocorticoids appear to be a potentially effective treatment strategy. Hence, AKI due to CPIs may be caused by a unique mechanism of action linked to reprogramming of the immune system, leading to loss of tolerance., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Acute kidney injury (AKI) is exacerbated in C-reactive protein transgenic mice but alleviated in Smad3 knockout mice. Here we used C-reactive protein transgenic/Smad3 wild-type and C-reactive protein transgenic/Smad3 knockout mice to investigate the signaling mechanisms by which C-reactive protein promotes AKI. Serum creatinine was elevated, and the extent of tubular epithelial cell necrosis following ischemia/reperfusion-induced AKI was greater in C-reactive protein transgenics but was blunted when Smad3 was deleted. Exacerbation of AKI in C-reactive protein transgenics was associated with increased TGF-β/Smad3 signaling and expression of the cyclin kinase inhibitor p27, but decreased phosphorylated CDK2 and expression of cyclin E. Concomitantly, tubular epithelial cell proliferation was arrested at the G1 phase in C-reactive protein transgenics with fewer cells entering the S-phase cell cycle as evidenced by fewer bromodeoxyuridine-positive cells. In contrast, the protection from AKI in C-reactive protein transgenic/Smad3 knockout mice was associated with decreased expression of p27 and promotion of CDK2/cyclin E-dependent G1/S transition of tubular epithelial cells. In vitro studies using tubular epithelial cells showed that C-reactive protein activates Smad3 via both TGF-β-dependent and ERK/MAPK cross talk mechanisms, Smad3 bound directly to p27, and blockade of Smad3 or the Fc receptor CD32 prevented C-reactive protein-induced p27-dependent G1 cell cycle arrest. In vivo, treatment of C-reactive protein transgenics with a Smad3 inhibitor largely improved AKI outcomes. Thus, C-reactive protein may promote AKI by impairing tubular epithelial cell regeneration via the CD32-Smad3-p27-driven inhibition of the CDK2/cyclin E complex. Targeting Smad3 may offer a new treatment approach for AKI., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Severe obesity is associated with increased risk of kidney disease. Whether bariatric surgery reduces the risk of adverse kidney outcomes is uncertain. To resolve this we compared the risk of estimated glomerular filtration rate (eGFR) decline of ≥30% and doubling of serum creatinine or end-stage renal disease (ESRD) in 985 patients who underwent bariatric surgery with 985 patients who did not undergo such surgery. Patients were matched on demographics, baseline body mass index, eGFR, comorbidities, and previous nutrition clinic use. Mean age was 45 years, 97% were white, 80% were female, and 33% had baseline eGFR <90 ml/min per 1.73 m(2). Mean 1-year weight loss was 40.4 kg in the surgery group compared with 1.4 kg in the matched cohort. Over a median follow-up of 4.4 years, 85 surgery patients had an eGFR decline of ≥30% (22 had doubling of serum creatinine/ESRD). Over a median follow-up of 3.8 years, 177 patients in the matched cohort had an eGFR decline of ≥30% (50 had doubling of serum creatinine/ESRD). In adjusted analysis, bariatric surgery patients had a significant 58% lower risk for an eGFR decline of ≥30% (hazard ratio 0.42, 95% confidence interval 0.32-0.55) and 57% lower risk of doubling of serum creatinine or ESRD (hazard ratio 0.43, 95% confidence interval: 0.26-0.71) compared with the matched cohort. Results were generally consistent among subgroups of patients with and without eGFR <90 ml/min per 1.73 m(2), hypertension, and diabetes. Thus, bariatric surgery may be an option to prevent kidney function decline in severely obese individuals., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Exposure to nephrotoxic medication is among the most common causes of acute kidney injury (AKI) in hospitalized patients. Here we conducted a prospective quality improvement project implementing a systematic Electronic Health Record screening and decision support process (trigger) in our quaternary pediatric inpatient hospital. Eligible patients were noncritically ill hospitalized children receiving an intravenous aminoglycoside for more than 3 days or more than 3 nephrotoxins simultaneously (exposure) from September 2011 through March 2015. Pharmacists recommended daily serum creatinine monitoring in exposed patients after appearance on the trigger report and AKI was defined by the Kidney Disease Improving Global Outcomes AKI criteria. A total of 1749 patients accounted for 2358 separate hospital admissions during which a total of 3243 episodes of nephrotoxin exposure were identified with 170 patients (9.7%) experiencing 2 or more exposures. A total of 575 individual AKI episodes occurred over the 43-month study period. Overall, the exposure rate decreased by 38% (11.63-7.24 exposures/1000 patient days), and the AKI rate decreased by 64% (2.96-1.06 episodes/1000 patient days). Assuming initial baseline exposure rates would have persisted without our project implementation, we estimate 633 exposures and 398 AKI episodes were avoided. Thus, systematic surveillance for nephrotoxic medication exposure and near real-time AKI risk can lead to sustained reductions in avoidable harm. These interventions and outcomes are translatable to other pediatric and nonpediatric hospitalized settings., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Tissue preconditioning, whereby various short-term stressors initiate organ resistance to subsequent injury, is well recognized. However, clinical preconditioning of the kidney for protection against acute kidney injury (AKI) has not been established. Here we tested whether a pro-oxidant agent, iron sucrose, combined with a protoporphyrin (Sn protoporphyrin), can induce preconditioning and protect against acute renal failure. Mice were pretreated with iron sucrose, protoporphyrin, cyanocobalamin, iron sucrose and protoporphyrin, or iron sucrose and cyanocobalamin. Eighteen hours later, ischemic, maleate, or glycerol models of AKI were induced, and its severity was assessed the following day (blood urea nitrogen, plasma creatinine concentrations; post-ischemic histology). Agent impact on cytoprotective gene expression (heme oxygenase 1, hepcidin, haptoglobin, hemopexin, α1-antitrypsin, α1-microglobulin, IL-10) was assessed as renal mRNA and protein levels. AKI-associated myocardial injury was gauged by plasma troponin I levels. Combination agent administration upregulated multiple cytoprotective genes and, unlike single agent administration, conferred marked protection against each tested model of acute renal failure. Heme oxygenase was shown to be a marked contributor to this cytoprotective effect. Preconditioning also blunted AKI-induced cardiac troponin release. Thus, iron sucrose and protoporphyrin administration can upregulate diverse cytoprotective genes and protect against acute renal failure. Associated cardiac protection implies potential relevance to both AKI and its associated adverse downstream effects., (Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)