Calcineurin inhibitor induced nephrotoxicity in steroid resistant nephrotic syndrome

Prolonged remission after cyclophosphamide or tacrolimus treatment in childhood nephrotic syndrome: a cohort study

BACKGROUND

Steroid-sparing immunosuppression is used in 50% of children with nephrotic syndrome, to prevent relapses and steroid-related toxicity. However, rates and predictors of prolonged remission after cyclophosphamide and tacrolimus are uncertain.

METHODS

Retrospective analysis of children (1-18 years) enrolled in a longitudinal cohort. We included children diagnosed with steroid-sensitive nephrotic syndrome between 1996-2019 from Toronto, Canada. The exposure was cyclophosphamide or tacrolimus initiation. The primary outcome was prolonged remission (no further relapse or steroid-sparing immunosuppression). We evaluated predictors of prolonged remission and calcineurin inhibitor nephrotoxicity by logistic regression.

RESULTS

Of 578 children with steroid-sensitive nephrotic syndrome, 252 received cyclophosphamide and 120 received tacrolimus. Over median 5.4-year (IQR 2.4-9.1) follow-up, prolonged remission occurred in 72 (28.6%) after cyclophosphamide and 17 (14.2%) after tacrolimus. Relapse frequency decreased after initiation of either medication. Lower prior relapse rate, more recent treatment era, and female sex were predictive of prolonged remission after cyclophosphamide treatment. Use of tacrolimus as the first steroid-sparing medication was the only factor predictive of calcineurin inhibitor nephrotoxicity.

CONCLUSIONS

Less than one-third of children achieve prolonged remission after initiating cyclophosphamide or tacrolimus, although both reduce short-term relapse rates. Few factors predict prolonged remission after cyclophosphamide or tacrolimus use, or calcineurin inhibitor nephrotoxicity.

Intravenous cyclophosphamide therapy in children with calcineurin inhibitor-resistant steroid-resistant nephrotic syndrome in a resource-limited setting

BACKGROUND

In pediatric steroid-resistant nephrotic syndrome (SRNS), calcineurin inhibitors (CNIs) are recommended as first-line therapy, with efficacy ranging between 60 and 80%, implying a substantial proportion will exhibit CNI resistance. Which alternate immunosuppressive therapy should be used in non-genetic pediatric SRNS exhibiting CNI resistance is especially relevant in low- to middle-income countries (LMIC), where the prohibitive costs of certain drugs such as monoclonal antibodies often determine therapy choice.

METHODS

The primary objective was to assess the efficacy of intravenous cyclophosphamide in a proportion of children aged 1-18 years with CNI-resistant SRNS with a complete response (CR) or partial response (PR) at 6 months from commencement of pulse therapy. The secondary objectives were to assess the proportion and profile of infections and adverse effects.

RESULTS

Of 90 children with idiopathic SRNS presenting between January 2013 and December 2022, 29 (32.2%) had CNI resistance and were enrolled. They were administered monthly intravenous cyclophosphamide pulses (6 pulses). Median (IQR) duration of follow-up was 48 (29.5, 63.5) months. At the end of 6 months of cyclophosphamide therapy, 13 (44.8%) attained CR and 4 (13.8%) attained PR, with an overall cyclophosphamide success rate of 58.6%. The efficacy of intravenous cyclophosphamide was higher in secondary (9/10; 90%) versus primary CNI resistance (8/19; 42.1%) (p = 0.029). Three children (3/29; 10.3%) developed systemic infections within 12 months of initiation of cyclophosphamide therapy, similar to the rate of systemic infections among children receiving CNI for SRNS management (6/41; 14.6%) (p = 0.85).

CONCLUSIONS

It is prudent to try intravenous cyclophosphamide in CNI-resistant SRNS in LMIC, given the reasonable cost and good efficacy rates (58.6%).

Comparison of Urinary Beta-2 Microglobulin Levels in Children with SSNS and Calcineurin Inhibitor-Treated SRNS

Background

While the utility of beta-2 microglobulin (β2M) has been explored in various renal conditions to identify tubulointerstitial damage, it has not been adequately studied in nephrotic syndrome. The primary objective of the study was to compare urinary β2M levels in children with steroid-sensitive nephrotic syndrome (SSNS) and steroid-resistant nephrotic syndrome (SRNS) in disease remission.

Materials and Methods

This cross-sectional study was done at a tertiary care hospital between April 2019 and March 2020. Sixty children (2-18 years) with SSNS and SRNS (30 in each group) in remission were enrolled. SRNS patients were included after ≥1 year of treatment with calcineurin inhibitors (CNIs). Biochemical investigations were done to confirm remission; spot samples for urinary β2M were collected and estimation was done by an enzyme-linked immunosorbent assay (ELISA)-based kit.

Results

Of the 60 children, 63% were boys. The median (interquartile range [IQR]) age at enrollment for SSNS and SRNS patients was 7 (4.1-9) and 11 (8.3-12) years, respectively. Urinary β2M levels were significantly higher in SRNS patients compared to SSNS patients (2.6 vs. 0.75 mg/ml, P < 0.0001). Patients who received cyclosporine for >2 years had higher median urinary β2M levels compared to those who received it for a shorter period (2.63 vs. 1.83 mg/ml, P = 0.03). Median β2M levels were higher in focal segmental glomerulosclerosis than minimal change disease (3.5 vs. 2.5 mg/ml).

Conclusion

Urinary β2M levels were higher in SRNS compared to SSNS disease in remission, and β2M levels correlated well with CNI use of >2 years. It appears to be a promising noninvasive tool to identify early tubular damage and progression in patients with nephrotic syndrome, especially SRNS.

Sequential rituximab therapy sustains remission of nephrotic syndrome but carries high risk of adverse effects

BACKGROUND

Sequential rituximab (RTX) administration has emerged as an important strategy to sustain remission of disease in patients with difficult-to-treat nephrotic syndrome.

METHODS

We report the efficacy and safety of sequential therapy with two or more courses of intravenous RTX in 250 patients with difficult-to-treat steroid dependence (n = 127) and calcineurin inhibitor (CNI)-dependent or CNI-refractory steroid resistance (n = 123) managed at one center during 2015-2021. Subsets of patients were cross-sectionally tested for hypogammaglobulinemia, seroprotection against and hyporesponsiveness to vaccines for hepatitis B and tetanus, BK/JC viruria and human antichimeric antibodies (HACAs).

RESULTS

Sequential RTX therapy, initiated at a median of 10 years [interquartile range (IQR) 7.3-14.4], was administered for 1.8 courses/person-year [95% confidence interval (CI) 1.7-2.0] over 2.0 years (95% CI 1.2-3.0). Therapy was associated with postponement of relapses by a median of 3 years in patients with steroid-sensitive disease and 2 years in those with steroid resistance. Relapses were reduced by a mean of 2.0 relapses/person-year (95% CI 1.8-2.2), enabling a reduction in prednisolone dose to 0.04 mg/kg/day (95% CI 0.01-0.11) and withdrawal of additional immunosuppression in 154 (62%) patients. RTX-associated adverse events, occurring at 0.20 events/person-year (95% CI 0.17-0.23), were chiefly comprised of infusion reactions (n = 108) and infections (n = 46); serious adverse events were observed in 10.8% patients, at 0.03 events/person-year (95% CI 0.02-0.05). Hypogammaglobulinemia was observed in 35% of 177 patients and was moderate to severe in 8.5% of cases. Rates of seroprotection at baseline and response following vaccination were lower for hepatitis B [1.9% and 29.4% (n = 52)] than tetanus [65.5% and 34.5% (n = 58)]. BK/JC viruria, without viremia, was observed in 7.3% of 109 cases. A total of 19 of 107 patients (17.8%) had HACAs, which were associated with B cell nondepletion and serum sickness. Age at therapy of <9-10 years was associated with a risk of early relapse, treatment failure and hypogammaglobulinemia following RTX therapy.

CONCLUSIONS

Sequential therapy with RTX effectively reduces relapses in patients with difficult-to-treat steroid- and/or CNI-dependent or CNI-refractory nephrotic syndrome. Therapy is associated with high rates of hypogammaglobulinemia and infusion reactions.

Efficacy of rituximab versus tacrolimus in difficult-to-treat steroid-sensitive nephrotic syndrome: an open-label pilot randomized controlled trial

BACKGROUND

Rituximab and tacrolimus are therapies reserved for patients with frequently relapsing or steroid-dependent nephrotic syndrome who have failed conventional steroid-sparing agents. Given their toxicities, demonstrating non-inferiority of rituximab to tacrolimus may enable choice between these medications.

METHODS

This investigator-initiated, single-center, open-label, pilot randomized controlled trial examined the non-inferiority of two doses of intravenous (IV) rituximab given one-week apart to oral therapy with tacrolimus (1:1 allocation), in maintaining sustained remission over 12 months follow-up, in patients with difficult-to-treat steroid-sensitive nephrotic syndrome, defined as frequently relapsing or steroid-dependent disease that had failed ≥ 2 steroid-sparing strategies. Secondary outcomes included frequency of relapses, proportion with frequent relapses, time to relapse and frequent relapses, and adverse events (CTRI/2018/11/016342).

RESULTS

Baseline characteristics were comparable for 41 patients randomized to receive rituximab (n = 21) or tacrolimus (n = 20). While 55% of patients in each limb were in sustained remission at 1 year, non-inferiority of rituximab to tacrolimus was not demonstrated (mean difference 0%; 95% CI - 30.8%, 30.8%; non-inferiority limit - 20%; P = 0.50). Frequent relapses were more common in patients administered rituximab compared to tacrolimus (risk difference 30%, 95% CI 7.0, 53.0, P = 0.023). Both groups showed similar reductions in relapse rates and prednisolone use. Common adverse events were infusion-related with rituximab and gastrointestinal symptoms with tacrolimus.

CONCLUSIONS

Therapy with rituximab was not shown to be non-inferior to 12-months treatment with tacrolimus in maintaining remission in patients with difficult-to-treat steroid-sensitive nephrotic syndrome. Frequent relapses were more common with rituximab. While effective, both agents require close monitoring for adverse events. A higher resolution version of the Graphical abstract is available as Supplementary information.

Early Prediction of Tacrolimus-Induced Tubular Toxicity in Pediatric Refractory Nephrotic Syndrome Using Machine Learning

Background and Aims: Tacrolimus(TAC)-induced nephrotoxicity, which has a large individual variation, may lead to treatment failure or even the end-stage renal disease. However, there is still a lack of effective models for the early prediction of TAC-induced nephrotoxicity, especially in nephrotic syndrome(NS). We aimed to develop and validate a predictive model of TAC-induced tubular toxicity in children with NS using machine learning based on comprehensive clinical and genetic variables. Materials and Methods: A retrospective cohort of 218 children with NS admitted between June 2013 and December 2018 was used to establish the models, and 11 children were prospectively enrolled for external validation. We screened 47 clinical features and 244 genetic variables. The changes in urine N- acetyl- β-D- glucosaminidase(NAG) levels before and after administration was used as an indicator of renal tubular toxicity. Results: Five machine learning algorithms, including extreme gradient boosting (XGBoost), gradient boosting decision tree (GBDT), extremely random trees (ET), random forest (RF), and logistic regression (LR) were used for model generation and validation. Four genetic variables, including TRPC6 rs3824934_GG, HSD11B1 rs846910_AG, MAP2K6 rs17823202_GG, and SCARB2 rs6823680_CC were incorporated into the final model. The XGBoost model has the best performance: sensitivity 75%, specificity 77.8%, accuracy 77.3%, and AUC 78.9%. Conclusion: A pre-administration model with good performance for predicting TAC-induced nephrotoxicity in NS was developed and validated using machine learning based on genetic factors. Physicians can estimate the possibility of nephrotoxicity in NS patients using this simple and accurate model to optimize treatment regimen before administration or to intervene in time after administration to avoid kidney damage.

Steroid-resistant Nephrotic Syndrome in Children: A Mini-review on Genetic Mechanisms, Predictive Biomarkers and Pharmacotherapy Strategies

Steroid-resistant nephrotic syndrome (SRNS) constitutes the second most frequent cause of chronic kidney disease in childhood. The etiology of SRNS remains largely unknown and no standardized treatment exists. Recent advances in genomics have helped to build understanding of the molecular mechanisms and pathogenesis of the disease. The genetic polymorphisms in genes encoding proteins which are involved in the pharmacokinetics and pharmacodynamics of glucocorticoids (GCs) partially account for the different responses between patients with nephrotic syndrome. More importantly, single-gene causation in podocytes-associated proteins was found in approximately 30% of SRNS patients. Some potential biomarkers have been tested for their abilities to discriminate against pediatric patients who are sensitive to GCs treatment and patients who are resistant to the same therapy. This article reviews the recent findings on genetic mechanisms, predictive biomarkers and current therapies for SRNS with the goal to improve the management of children with this syndrome.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

JUSTIFICATION

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

OBJECTIVE

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

PROCESS

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

RECOMMENDATIONS

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

Steroid Sensitive Nephrotic Syndrome: Revised Guidelines

Justification

Steroid sensitive nephrotic syndrome (SSNS) is one of the most common chronic kidney diseases in children. These guidelines update the existing Indian Society of Pediatric Nephrology recommendations on its management.

Objective

To frame revised guidelines on diagnosis, evaluation, management and supportive care of patients with the illness.

Process

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by review of literature and evaluation of evidence by experts in two face-to-face meetings.

Recommendations

The initial statements provide advice for evaluation at onset and follow up and indications for kidney biopsy. Subsequent statements provide recommendations for management of the first episode of illness and of disease relapses. Recommendations on the use of immunosuppressive strategies in patients with frequent relapses and steroid dependence are accompanied by suggestions for step-wise approach and plan of monitoring. Guidance is also provided regarding the management of common complications including edema, hypovolemia and serious infections. Advice on immunization and transition of care is given. The revised guideline is intended to improve the management and outcomes of patients with SSNS, and provide directions for future research.

L-Carnitine protects against tacrolimus-induced renal injury by attenuating programmed cell death via PI3K/AKT/PTEN signaling

Reducing immunosuppressant-related complications using conventional drugs is an efficient therapeutic strategy. L-carnitine (LC) has been shown to protect against various types of renal injury. In this study, we investigated the renoprotective effects of LC in a rat model of chronic tacrolimus (TAC) nephropathy. SD rats were injected with TAC (1.5 mg · kg-1 · d-1, sc) for 4 weeks. Renoprotective effects of LC were assessed in terms of renal function, histopathology, oxidative stress, expression of inflammatory and fibrotic cytokines, programmed cell death (pyroptosis, apoptosis, and autophagy), mitochondrial function, and PI3K/AKT/PTEN signaling. Chronic TAC nephropathy was characterized by severe renal dysfunction and typical histological features of chronic nephropathy. At a molecular level, TAC markedly increased the expression of inflammatory and fibrotic cytokines in the kidney, induced oxidative stress, and led to mitochondrial dysfunction and programmed cell death through activation of PI3K/AKT and inhibition of PTEN. Coadministration of LC (200 mg · kg-1 · d-1, ip) caused a prominent improvement in renal function and ameliorated histological changes of kidneys in TAC-treated rats. Furthermore, LC exerted anti-inflammatory and antioxidant effects, prevented mitochondrial dysfunction, and modulated the expression of a series of apoptosis- and autophagy-controlling genes to promote cell survival. Human kidney proximal tubular epithelial cells (HK-2 cells) were treated with TAC (50 μg/mL) in vitro, which induced production of intracellular reactive oxygen species and expression of an array of genes controlling programmed cell death (pyroptosis, apoptosis, and autophagy) through interfering with PI3K/AKT/PTEN signaling. The harmful responses of HK-2 cells to TAC were significantly attenuated by cotreatment with LC and the PI3K inhibitor LY294002 (25 μM). In conclusion, LC treatment protects against chronic TAC nephropathy through interfering the PI3K/AKT/PTEN signaling.

Current understandings in treating children with steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatric nephrologists. SRNS is viewed as a heterogeneous disease entity including immune-based and monogenic aetiologies. Because SRNS is rare, treatment strategies are individualized and vary among centres of expertise. Calcineurin inhibitors (CNI) have been effectively used to induce remission in patients with immune-based SRNS; however, there is still no consensus on treating children who become either CNI-dependent or CNI-resistant. Rituximab is a steroid-sparing agent for patients with steroid-sensitive nephrotic syndrome, but its efficacy in SRNS is controversial. Recently, several novel monoclonal antibodies are emerging as treatment option, but their efficacy remains to be seen. Non-immune therapies, such as angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, have been proven efficacious in children with SRNS and are recommended as adjuvant agents. This review summarizes and discusses our current understandings in treating children with idiopathic SRNS.

Assessing the Intestinal Permeability and Anti-Inflammatory Potential of Sesquiterpene Lactones from Chicory

Cichorium intybus L. has recently gained major attention due to large quantities of health-promoting compounds in its roots, such as inulin and sesquiterpene lactones (SLs). Chicory is the main dietary source of SLs, which have underexplored bioactive potential. In this study, we assessed the capacity of SLs to permeate the intestinal barrier to become physiologically available, using in silico predictions and in vitro studies with the well-established cell model of the human intestinal mucosa (differentiated Caco-2 cells). The potential of SLs to modulate inflammatory responses through modulation of the nuclear factor of activated T-cells (NFAT) pathway was also evaluated, using a yeast reporter system. Lactucopicrin was revealed as the most permeable chicory SL in the intestinal barrier model, but it had low anti-inflammatory potential. The SL with the highest anti-inflammatory potential was 11β,13-dihydrolactucin, which inhibited up to 54% of Calcineurin-responsive zinc finger (Crz1) activation, concomitantly with the impairment of the nuclear accumulation of Crz1, the yeast orthologue of human NFAT.

Tacrolimus treatment in childhood refractory nephrotic syndrome: A retrospective study on efficacy, therapeutic drug monitoring, and contributing factors to variable blood tacrolimus levels

Tacrolimus, an immunosuppressive drug, was recommended by the 2012 KDIGO guidelines to treat nephrotic syndrome (NS) in children and adults. However, it has high interpatient pharmacokinetic variability and exposure levels should be monitored, although there are no specified target concentrations. This retrospective study aimed to review efficacy and safety after concomitant treatment with tacrolimus and prednisone, and to identify factors that contribute to the variable blood-trough-concentration-to-dose (C₀/Dose) ratio in children with refractory NS (RNS). A 6-month therapy induced complete or partial remission in 95% of patients. One-year follow-up indicated a high remission rate and low nephrotoxicity. Under maintenance dosages, approximately 95% of the C₀ values were 2-7 ng/mL. Body weight (BW), age, CYP3A5 polymorphisms were the factors affecting the C₀/Dose ratio. The C₀/Dose ratio in patients with a BW of <20 kg was 1.5-fold than that in patients with BW of ≥40 kg. Moreover, the C₀/Dose ratio in patients aged 1-≤6 and 6-≤12 years was significantly lower than that in patients aged 12-≤18 years, by 25% and 48%, respectively. There were no significant association between CYP3A5 genotyping and C₀/Dose ratio in younger children (1-≤6 years), rather than older children (6-≤18 years). In conclusion, routine CYP3A5 genotyping should be considered in children aged over 6 years and exposure levels (C₀) of 2-7 ng/mL may be feasible when tacrolimus is combined with low-dose prednisone to treat childhood RNS.

Off-label use of tacrolimus in children with glomerular disease: Effectiveness, safety and pharmacokinetics

Glomerular diseases are leading causes of end-stage renal disease in children. Tacrolimus is frequently used off-label in the treatment of glomerular diseases. The effectiveness, safety and pharmacokinetic data of tacrolimus in the treatment of glomerular diseases in children are reviewed in this paper to provide evidence to support its rational use in clinical practice. The remission rates in previously published studies were different. In 19 clinical trials on children with nephrotic syndrome, the overall remission rate was 52.6-97.6%. In four clinical trials on children with lupus nephritis, the overall remission rate was 81.8-89.5%. In a pilot study with paediatric Henoch-Schönlein purpura nephritis patients, the overall remission rate was 100.0%. Infection, nephrotoxicity, gastrointestinal symptoms and hypertension are the most common adverse events. Body weight, age, CYP3A5 genotype, cystatin-C and daily dose of tacrolimus may have significant effects on the pharmacokinetics of tacrolimus in children with glomerular disease. More prospective controlled trials with long follow-up are needed to demonstrate definitely the effectiveness, safety and pharmacokinetics of tacrolimus in children with glomerular diseases.

Infrequent tacrolimus-induced nephrotoxicity in French patients with steroid-dependent nephrotic syndrome

BACKGROUND

Chronic nephrotoxicity with potentially irreversible lesions is a major concern regarding calcineurin inhibitor (CNI) treatment in children with severe forms of idiopathic nephrotic syndrome (INS).

CASE-DIAGNOSIS/TREATMENT

We retrospectively included all children on CNI for steroid-dependent INS with a duration of CNI treatment of more than 1 year. Only patients in whom CNI could not be replaced by mycophenolate mofetil were included. All included patients underwent a kidney biopsy. All results were expressed as median and range. Twenty-one children (6 girls) were included. Age at disease onset was 49 (29-66) months and treatment duration on CNI was 30 (20-45) months. Age at kidney biopsy was 108 (78-170) months. Number of relapses was 7 (3-9) since disease onset. Serum creatinine level was transiently and moderately increased in two patients. Kidney biopsy revealed minimal change disease in 20/21 patients and focal segmental glomerulosclerosis in 1/21. Evidence for chronic CNI nephrotoxicity was found in one patient revealed by arteriolar hyalinosis and fibrosis in 50% of glomeruli.

CONCLUSIONS

CNI-induced chronic nephrotoxicity was infrequent. In patients who require long-term and/or high-dose CNI treatment, kidney biopsies might be useful to exclude chronic CNI-induced lesions.

Management of steroid-resistant nephrotic syndrome in children and adolescents

More than 85% of children and adolescents (majority between 1-12 years old) with idiopathic nephrotic syndrome show complete remission of proteinuria following daily treatment with corticosteroids. Patients who do not show remission after 4 weeks' treatment with daily prednisolone are considered to have steroid-resistant nephrotic syndrome (SRNS). Renal histology in most patients shows presence of focal segmental glomerulosclerosis, minimal change disease, and (rarely) mesangioproliferative glomerulonephritis. A third of patients with SRNS show mutations in one of the key podocyte genes. The remaining cases of SRNS are probably caused by an undefined circulating factor. Treatment with calcineurin inhibitors (ciclosporin and tacrolimus) is the standard of care for patients with non-genetic SRNS, and approximately 70% of patients achieve a complete or partial remission and show satisfactory long-term outcome. Additional treatment with drugs that inhibit the renin-angiotensin axis is recommended for hypertension and for reducing remaining proteinuria. Patients with SRNS who do not respond to treatment with calcineurin inhibitors or other immunosuppressive drugs can show declining kidney function and are at risk for end-stage renal failure. Approximately a third of those who undergo renal transplantation show recurrent focal segmental glomerulosclerosis in the allograft and often respond to combined treatment with plasma exchange, rituximab, and intensified immunosuppression.

miR-499 Ameliorates Podocyte Injury by Targeting Calcineurin in Minimal Change Disease

BACKGROUND

Podocyte injury is a hallmark of minimal change disease (MCD). Calcineurin inhibitors have been widely used in the current treatment of MCD, and miR-499 may target calcineurin. We aimed to study the function of miR-499 in MCD and test whether miR-499 delivery can improve MCD.

METHODS

An MCD mouse model was generated using puromycin aminonucleoside (PAN). MiR-499 was delivered using lentiviruses. Biochemical indicators including serum albumin, triglyceride, cholesterol, and 24-h urine protein were determined. Targets of miR-499 were confirmed using reporter gene activity assays. The ultrastructure of podocytes was analyzed using transmission electron microscopy.

RESULTS

MiR-499 significantly improved MCD-related symptoms and signs. Foot-process effacement was caused by PAN and partially reversed by miR-499. We identified that both CnAα and CnAβ were targets of miR-499, and were overexpressed in the presence of PAN. However, miR-499 reduced the expression of CnAα and CnAβ, leading to a decreased activity of calcineurin signaling in mouse podocytes in vitro and in vivo. In addition, miR-499 recovered PAN-induced reduction of cell viability.

CONCLUSIONS

MiR-499 ameliorated podocyte injury by targeting CnAα and CnAβ in a PAN-induced MCD mouse model. Delivery of miR-499 can be a novel strategy for MCD treatment.

Efficacy and Safety of Cyclosporine versus Tacrolimus in Steroid and Cyclophosphamide Resistant Nephrotic Syndrome: A Prospective Study

Calcineurin inhibitors (CNIs) are the preferred drugs for treatment of childhood steroid-resistant nephrotic syndrome (SRNS) who are also resistant to cyclophosphamide (CYC). Although few studies have shown a benefit of one over the other, efficacy and safety of either CNIs (tacrolimus [TAC] or cyclosporine [CSA]) in this special population remained to be assessed in long-term studies. Forty-five children with SRNS who were also resistant to CYC (CYC-SRNS) from January 2006 to June 2011, were included in the study. Patients were treated with CNI either TAC or CSA based on 1:1 allocations and were prospectively observed. Patients who were nonresponsive to CNIs had been treated with mycophenolate mofetil. Outcomes were measured in terms of remission of NS, adverse effects of drugs, and progression of disease. After 6 months of treatment, 16/23 (69.5%) patients on CSA achieved remission and 18/22 (81.8%) on TAC achieved remission (P = 0.3). The side effects hypertrichosis, and gum hyperplasia were significantly less in TAC group as compared to CSA group (P < 0.001). The 1-, 2-, 3-, 4-, and 5-year estimated renal survival (doubling of serum creatinine as event) in CSA group was 96%, 91%, 85%, 54%, and 33% and in TAC group was 96%, 95%, 90%, 89%, and 79%, respectively (P = 0.02). Although TAC and CSA are equally efficacious, TAC has significantly less side effects. The long-term outcome of renal function was significantly better in patients who were treated with TAC as compared to CSA.

Cyclosporine-based immunosuppressive therapy for patients with steroid-resistant focal segmental glomerulosclerosis: a meta-analysis

OBJECTIVE

Focal segmental glomerulosclerosis (FSGS) is a leading cause of end-stage kidney disease that requires immunosuppressive treatment as therapy. Few studies have been specifically designed to assess the efficacy of cyclosporine (CSA) in patients with steroid-resistant FSGS. This study investigated the efficacy of CSA-based therapy in steroid-resistant FSGS.

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched through April 30, 2014 using the keywords "cyclosporine", "steroid-resistant", "focal segmental glomerulosclerosis", and "FSGS". Studies with an adult and children with steroid-resistant primary FSGS treated with CSA-based therapy with or without steroid use were included. Complete, partial, and overall remission were the primary outcomes. Change in proteinuria, serum creatinine, and estimated glomerular filtration rate (eGFR) following treatment were secondary outcomes.

RESULTS

Seven randomized controlled trials with a total of 373 patients were included. Five studies were included in the meta-analysis to assess complete, partial, and overall remission of FSGS. Compared with other treatments, CSA-based therapy resulted in a significantly greater partial remission rate (p = .018), but complete (p = .226) or overall remission rate (p = .050). CSA-based therapy also resulted in similar change in proteinuria (p = .084), serum creatinine (p = .772), and eGFR (p = .155) compared with other therapy. Study limitations included small sample size and heterogeneity in age and comparative treatments across the studies.

CONCLUSIONS

Cyclosporin-based treatments provided a significantly better partial remission rate as compared with other therapies.

Mycophenolate mofetil is inferior to tacrolimus in sustaining remission in children with idiopathic steroid-resistant nephrotic syndrome

Studies of nephrotic syndrome show that substitution of calcineurin inhibitors by mycophenolate mofetil (MMF) enables sustained remission and corticosteroid sparing and avoids therapy associated adverse effects. However, controlled studies in patients with steroid resistance are lacking. Here we examined the effect of switching from therapy with tacrolimus to MMF on disease course in an open-label, one-to-one randomized, controlled trial on children (one to 18 years old), recently diagnosed with steroid-resistant nephrotic syndrome, at a referral center in India. Following six months of therapy with tacrolimus, patients with complete or partial remission were randomly assigned such that 29 received MMF while 31 received tacrolimus along with tapering prednisolone on alternate days for 12 months. On intention-to-treat analyses, the proportion of patients with a favorable outcome (sustained remission, infrequent relapses) at one year was significantly lower (44.8%) in the MMF group than in the tacrolimus group (90.3%). The incidence of relapses was significantly higher for patients treated with MMF than tacrolimus (mean difference: 1.05 relapses per person-year). While there was no difference in the proportion of patients with sustained remission, the risk of recurrence of steroid resistance was significantly higher for patients receiving MMF compared to tacrolimus (mean difference: 20.7%). Compared to tacrolimus, patients receiving MMF had a significantly (71%) lower likelihood of a favorable outcome and significantly increased risk of treatment failure (frequent relapses, steroid resistance). Thus, replacing tacrolimus with MMF after six months of tacrolimus therapy for steroid-resistant nephrotic syndrome in children is associated with significant risk of frequent relapses or recurrence of resistance. These findings have implications for guiding the duration of therapy with tacrolimus for steroid-resistant nephrotic syndrome.

Long-term outcome of idiopathic steroid-resistant nephrotic syndrome in children

BACKGROUND

Several recent studies have shown improved short-term outcome of steroid-resistant nephrotic syndrome (SRNS) in children; however, only a few studies have evaluated the long-term outcome. The aims of our study were to obtain detailed data and analyze the long-term outcome of children with SRNS.

METHODS

Sixty-nine children with idiopathic SRNS were enrolled and divided into two groups based on initial histopathological patterns: focal segmental glomerulosclerosis (FSGS) and minimal change (MC)/diffuse mesangial proliferation (DMP). The effects of initial treatment with the immunosuppressant of choice (cyclosporine or cyclophosphamide) on renal survival, remission, and incidence of complications were analyzed in both groups (4 subgroups).

RESULTS

The renal survival rate was significantly different among the four different subgroups based on different combinations of initial histopathological pattern (FSGS vs. MC/DMP) and initial immunosuppressant used for treating SRNS (cyclosporine vs. cyclophosphamide) (P = 0.013), with renal survival in the FSGS (cyclophosphamide) subgroup being especially low (54.6 %). Disease- and/or treatment-associated complications were relatively low; however, hypertension at last examination was observed in a considerable number of patients (31.9 %).

CONCLUSIONS

Our results suggest that a recently developed therapeutic regimen with cyclosporine considerably improves both the initial remission rate and the long-term renal survival rate of children with idiopathic SRNS.