Independent risk factors for chronic cyclosporine induced nephropathy in children with nephrotic syndrome

Factors associated with chronic calcineurin inhibitor nephrotoxicity in children with minimal-change disease

BACKGROUND

Calcineurin inhibitors (CNIs), such as cyclosporine (CsA) and tacrolimus (TAC), are commonly used to treat children with complicated minimal change nephrotic syndrome. However, chronic nephrotoxicity associated with CNIs poses a significant safety concern. This study aimed to identify the risk factors that contribute to chronic nephrotoxicity in these patients.

MATERIAL AND METHODS

Clinical and pathological data of MCD children treated with CsA or TAC in our center between 1 January 2003 and 31 December 2022, were retrospectively reviewed. Kidney biopsies were performed on 80 patients who received CNI treatment for more than 6 months.

RESULTS

Chronic CNI nephrotoxicity (striped interstitial fibrosis with tubular atrophy) was observed in 15% (12/80) of patients. Higher CNI culminating amounts were shown in patients who developed nephrotoxicity regardless of CsA or TAC treatment. Risk factors for chronic CNI nephrotoxicity included persistent nephrotic-range proteinuria for more than 30 days during CNI treatment, increased urinary NAG level, and CNI resistance. Multivariate analysis revealed that increased urinary NAG level and CNI resistance were the independent risk factors for chronic CNI nephrotoxicity in children with MCD.

CONCLUSION

MCD children who developed CNI resistance were susceptible to chronic CNI nephrotoxicity. Urinary NAG might be a valuable biomarker for CNI nephrotoxicity prediction in MCD children.

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.

Adult survivors of childhood-onset steroid-dependent and steroid-resistant nephrotic syndrome treated with cyclosporine: a long-term single-center experience

BACKGROUND

Although evidence has confirmed that cyclosporine (CS) is efficacious against childhood-onset steroid-dependent and steroid-resistant nephrotic syndrome (SD/SRNS), some patients may continue to relapse during adulthood. However, predictive factors for adult active disease and kidney complications, such as chronic kidney disease (CKD) and hypertension, in this cohort remain unknown.

METHODS

We conducted a retrospective study on the long-term outcomes of 81 young adults with childhood-onset SD/SRNS treated with CS. The primary endpoint was the probability of active disease into adulthood. The secondary endpoint was the probability of developing kidney complications.

RESULTS

At the last follow-up (median age, 23.2 years; median disease duration, 15.8 years), 44 adult patients (54%) continued to have active disease, whereas 16 patients developed CKD or hypertension, respectively. The proportion of patients developing kidney complications was similar between the active disease and long-term remission groups. Young age at NS onset and history of relapse during the initial CS (median, 31 months) were independent predictive factors for active disease. Acute kidney injury at NS onset, focal segmental glomerulosclerosis, and irreversible CS nephrotoxicity were identified as risk factors for the development of CKD, whereas older age was identified as a risk factor for the development of CKD and hypertension.

CONCLUSIONS

More than 50% of adult survivors treated with CS continued to have active disease, and each 20% developed CKD or hypertension. A long-term follow-up is necessary for patients with SD/SRNS to identify the development of kidney complications later in adulthood that can be attributed to prior disease and CS treatment in childhood, irrespective of disease activity. A higher resolution version of the Graphical abstract is available as Supplementary information.

Childhood nephrotic syndrome

Idiopathic nephrotic syndrome is the most common glomerular disease in children. Corticosteroids are the cornerstone of its treatment, and steroid response is the main prognostic factor. Most children respond to a cycle of oral steroids, and are defined as having steroid-sensitive nephrotic syndrome. Among the children who do not respond, defined as having steroid-resistant nephrotic syndrome, most respond to second-line immunosuppression, mainly with calcineurin inhibitors, and children in whom a response is not observed are described as multidrug resistant. The pathophysiology of nephrotic syndrome remains elusive. In cases of immune-mediated origin, dysregulation of immune cells and production of circulating factors that damage the glomerular filtration barrier have been described. Conversely, up to a third of cases of steroid-resistant nephrotic syndrome have a monogenic origin. Multidrug resistant nephrotic syndrome often leads to kidney failure and can cause relapse after kidney transplant. Although steroid-sensitive nephrotic syndrome does not affect renal function, most children with steroid-sensitive nephrotic syndrome have a relapsing course that requires repeated steroid cycles with significant side-effects. To minimise morbidity, some patients require steroid-sparing immunosuppressive agents, including levamisole, mycophenolate mofetil, calcineurin inhibitors, anti-CD20 monoclonal antibodies, and cyclophosphamide. Close monitoring and preventive measures are warranted at onset and during relapse to prevent acute complications (eg, hypovolaemia, acute kidney injury, infections, and thrombosis), whereas long-term management requires minimising treatment-related side-effects. A subset of patients have active disease into adulthood.

IPNA clinical practice recommendations for the diagnosis and management of children with steroid-sensitive nephrotic syndrome

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given.

Cyclosporine A C1.5 monitoring reflects the area under the curve in children with nephrotic syndrome: a single-center experience

BACKGROUND

The currently used single-monitoring method for drug-blood-level evaluation in cyclosporine A (CsA) treatment for nephrotic syndrome (NS) was established through hourly measurements based on adult organ transplantation. However, the pharmacokinetics may differ due to different concomitant medications, age, and conditions. This study was conducted to determine the measurement timing that best reflects the CsA area under the curve (AUC) in pediatric NS.

METHODS

This retrospective study included children aged 2-14 years who were started on CsA treatment for idiopathic NS during 2013-2020. AUC_0-4 was calculated from 7 points, before and 0.5, 1, 1.5, 2, 3, and 4 h after administration. Mean values at each timing were compared with age-dependent different drug forms. Correlation between AUC_0-4 and measurement timing was analyzed.

RESULTS

There were 13 patients (11 boys) whose median age during testing was 7.3 years, and the total number of measurements was 94. The highest timing of CsA concentrations was found in C₁ 59.6%. The content liquid used at younger ages had a faster absorption time to peak value and lower blood concentration than those of capsules. Among the significant correlations observed, AUC_0-4 and C_1.5 showed the strongest significant correlation coefficient (r = 0.93, P < 0.001).

CONCLUSION

In pediatric NS, CsA metabolism may be faster than that in previous organ transplantation. Compared with C₂, C_1.5 monitoring may result in better disease control as it can best reflect the AUC_0-4 and peak values associated with side effects, which are indicators of therapeutic efficacy.

Role of Tacrolimus C/D Ratio in the First Year After Pediatric Liver Transplantation

Background: The calcineurin inhibitor (CNI) tacrolimus (TAC) is a cornerstone agent in immunosuppressive therapy in pediatric liver transplantation (LTX). Adverse effects limit the use of CNI. In adults, calculating the individual TAC metabolism rate allows to estimate the transplant recipient's risk for therapy-associated complications. Methods: A retrospective, descriptive data analysis was performed in children who had undergone LTX in 2009-2017 and had received TAC twice daily in the first year after LTX. A weight-adjusted concentration/dose ratio (C/D ratio) was calculated [TAC trough level/(daily TAC dose/body weight)] every 3 months after LTX to estimate the average individual TAC metabolism rate. Depending on the C/D ratio, all patients were divided into two groups: fast metabolizers (FM) and slow metabolizers (SM). Clinical and laboratory parameters were analyzed as risk factors in both groups. Results: A total of 78 children (w 34, m 44, median age at LTX 2.4; 0.4-17.0 years) were enrolled in the study. FM (SM) had a mean C/D ratio of <51.83 (≥51.83) ng/ml/(mg/kg). FM were younger at the time of LTX (median age 1.7; 0.4-15.8 years) than SM (5.1, 0.4-17.0), p = 0.008. FM were more likely to have biliary atresia (20/39, 51%) compared to SM (11/39, 28%), p = 0.038, whereas SM were more likely to have progressive familial intrahepatic cholestasis (9/39, 23%) vs. in FM (1/39, 3%), p = 0.014. Epstein-Barr virus (EBV) infection occurred more frequently in FM (27/39, 69%) than SM (13/39, 33%), p = 0.002. Three FM developed post-transplant lymphoproliferative disorder. The annual change of renal function did not differ in both groups (slope FM 1.2 ± 0.6; SM 1.4 ± 0.8 ml/min/1.73 m2 per year, and p = 0.841). Conclusions: Calculation of individual, weight-adjusted TAC C/D ratio is a simple, effective, and cost-efficient tool for physicians to estimate the risk of therapy-associated complications and to initiate individual preventive adjustments after pediatric LTX. Lower TAC levels are tolerable in FM, especially in the presence of EBV infection, reduced renal function, or when receiving a liver transplant in the first 2 years of life.

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.

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.

Renal and Hepatic Health After Childhood Cancer

Childhood cancer survivors (CCSs) are at risk for renal and hepatic complications related to curative cancer treatments. Although acute renal and hepatic toxicities of cancer treatments are well described, data regarding long-term and late-occurring sequelae or their associations with acute sequelae are less robust. This article highlights the literature on the prevalence of and risk factors for late renal and hepatic toxicity in CCSs. Studies investigating these outcomes are needed to inform surveillance practices and the development of future frontline cancer treatment protocols.

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.

Idiopathic nephrotic syndrome in children

The incidence of idiopathic nephrotic syndrome (NS) is 1·15-16·9 per 100 000 children, varying by ethnicity and region. The cause remains unknown but the pathogenesis of idiopathic NS is thought to involve immune dysregulation, systemic circulating factors, or inherited structural abnormalities of the podocyte. Genetic risk is more commonly described among children with steroid-resistant disease. The mainstay of therapy is prednisone for the vast majority of patients who are steroid responsive; however, the disease can run a frequently relapsing course, necessitating the need for alternative immunosuppressive agents. Infection and venous thromboembolism are the main complications of NS with also increased risk of acute kidney injury. Prognosis in terms of long-term kidney outcome overall is excellent for steroid-responsive disease, and steroid resistance is an important determinant of future risk of chronic or end-stage kidney disease.

Calcineurin inhibitors and nephrotoxicity in children

BACKGROUND

Calcineurin inhibitors (CNIs) are commonly given to transplant recipients of kidneys and other solid organs and to patients with immune disorders, such as steroid-resistant nephrotic syndrome, steroid-dependent nephrotic syndrome, and frequent relapse nephrotic syndrome. Although CNIs remain the most effective available immunosuppressant agent, there is clinical concern regarding possible long-term nephrotoxicity. This concern is especially significant in children who have a longer life expectancy and greater growth rate.

DATA SOURCES

In this review, we analyzed the literatures to identify original articles that examined use of CNIs in children who received organ transplantation and nephropathy to assess the available evidence of their nephrotoxicity. PubMed, Elsevier, and Tompson ISI Web of Knowledge were searched for identifying relevant papers.

RESULTS

Clinical research supports the presence of CNI-related nephrotoxicity. However, some researchers have questioned the prevalence and seriousness of chronic CNIs nephrotoxicity, especially because the pathological lesions typically associated with long-term CNI use are nonspecific. Many researchers have focused on early markers of CNI nephrotoxicity, and the methods that may help prevent and manage nephrotoxicity.

CONCLUSIONS

Future research should focus on investigating early markers of CNI nephrotoxicity and strategies for improved immunosuppressant therapy, and developing alternative treatments. CNI-mediated nephrotoxicity should always be taken seriously in clinic.

Nephrotoxicity in children with frequently relapsing nephrotic syndrome receiving long-term cyclosporine treatment

BACKGROUND

Steroid-sparing drugs, such as cyclosporine, are recommended as treatment for children with frequently relapsing nephrotic syndrome (FRNS) and steroid-related toxicities. We recently reported a high rate of relapsing nephrotic syndrome 2 years after discontinuation of cyclosporine treatment, suggesting that long-term treatment is necessary. Cyclosporine-associated nephrotoxicity (CAN) is a potential side effect of long-term cyclosporine treatment.

METHODS

We retrospectively reviewed pediatric patients with FRNS treated with cyclosporine for ≥3 years at a single center between 1999 and 2012. The cyclosporine dose was adjusted to maintain the whole-blood cyclosporine trough level at 80-100 ng/ml for 6 months, at 60-80 ng/ml for 18 months, and then at around 50-60 ng/ml thereafter. Maintenance dose of prednisolone was not prescribed. CAN was graded in terms of arteriolar hyalinosis and the degree of interstitial fibrosis.

RESULTS

Thirty-six children (28 males) were enrolled in the study. The median age at the start of long-term cyclosporine treatment was 9.4 years. The median duration of the longest period of cyclosporine treatment was 4.5 years. Most CAN cases were characterized by arteriolar hyalinosis. The frequency of CAN was positively correlated with the duration of cyclosporine treatment, with an odds ratio (95% confidence interval) for CAN of 3.84 (0.79-18.74) after 2-5 years and 6.60 (1.18-36.94) after >5 years of cyclosporine treatment (vs. 0-2 years).

CONCLUSIONS

Although the frequency of CAN was correlated with the duration of cyclosporine treatment in our pediatric patient population, most cases of CAN involved arteriolar hyalinosis. We conclude that long-term cyclosporine treatment is useful for treating FRNS in children, providing its dose is controlled and kidney biopsies are regularly performed.

Effectiveness and nephrotoxicity of a 2-year medium dose of cyclosporine in pediatric patients with steroid-dependent nephrotic syndrome: determination of the need for follow-up kidney biopsy

BACKGROUND

High dose of cyclosporine (CyA) for ≥2 years in children with steroid-dependent nephrotic syndrome (SDNS) increases the risk for nephropathy. Considering this, risk can be lowered with lower doses of CyA; we evaluated the effects of a medium dose of CyA, with target serum level, C2, of 450 ng/ml, over a 2-year period of observation, to determine the need for follow-up kidney biopsy.

METHODS

We retrospectively evaluated C2 levels in 38 patients (17 males, 5.2 ± 2.9 years old) with SDNS at treatment initiation, at 6, 12 and 18 months during treatment, and at the time of kidney biopsy, 2-year after treatment initiation. Fifteen patients were also treated with mizoribine or mycophenolate mofetil. A number of relapses-per-patient-per-year, relative to SDNS onset and initiation of CyA treatment, were evaluated. Serum levels of total protein, albumin and total cholesterol, blood urea nitrogen level, and the estimated glomerular filtration rate were measured at treatment initiation and at 1- and 2-year post-treatment initiation.

RESULTS

Only one very mild case of CyA-associated nephrotoxicity was identified based on biopsy results at 2-year post-treatment initiation. C2 concentrations were maintained at 422.2 ± 133.5 ng/ml and the number of relapses decreased from 3.0 relapses-per-patient-per-year prior to CyA treatment to 0.47 relapses-per-patient-per-year after CyA treatment. No effects of the treatment on the estimated glomerular filtration rate were noted.

CONCLUSION

A 2-year treatment with a medium dose of cyclosporine A with or without other immunosuppressive agents is relatively safe with regard to the development of cyclosporine A nephrotoxicity.

Predictive risk factors of steroid dependent nephrotic syndrome in children

Background:

Development of steroid dependency is one of the difficult problems in the management of children with idiopathic nephrotic syndrome, leading to increased morbidity, complications and cost of treatment. Thus, predicting early in the disease course will be useful in counseling parents and may improve treatment strategy.

Objectives:

To determine the clinical characteristics that can predict the development of steroid dependency early in the initial episodes of steroid sensitive nephrotic syndrome (SSNS).

Patients and Methods:

The study included 52 children with SSNS. Their ages ranged from 3 to 16 years. Patients were divided into two groups. Group A consisted of 24 patients with steroid dependency or frequent relapses nephrotic syndrome and group B consisted of 28 patients with complete remission or recurrent nephrotic syndrome. Data obtained retrospectively from patients’ files.

Results:

Children who require a cumulative steroid dose equal or more than 140 mg/kg to maintain remission during the first 6 months of the disease are at high risk to require steroid sparing agents (SSA) for disease control, and who did not achieve remission by day 20 of the initial prednisone course became steroid dependent with 96% specificity but with low sensitivity (50%). All steroid dependent children in this study showed relapses associated significantly with upper respiratory tract infections.

Conclusions:

Cumulative steroid dose in the first 6 months of treatment and the need of more than 20 days to achieve initial remission can predict steroid dependency in children with nephrotic syndrome.

Cyclosporine A induced histological changes of Cathepsin L and CD2AP expression in renal glomeruli and tubules

BACKGROUND

Cyclosporine A (CsA) is used globally as an immunosuppressant for the treatment of immune-mediated nephrotic syndrome (NS). However, its long-term use causes nephrotoxicity characterized by tubulointerstitial injury and glomerulosclerosis. The present study aimed to investigate the associations between histomorphological findings and immunohistological expression of Cathepsin L (CatL) and CD2-associated protein (CD2AP) in patients with NS mediated with CsA.

METHODS

A total of 18 patients with child-onset NS were divided into two groups after treatment with CsA for 2 years (group A; n = 10) and more than 4 years (group B; n = 8), respectively. Analyses of relationships between tubulointerstitial disorders and expression of CatL and CD2AP proteins were performed using immunohistochemistry of paired renal specimens.

RESULTS

Glomeruli with arteriole hyalinization were significantly increased in both groups depending on dosage periods, although degrees of tubule and interstitial injury did not differ between groups. CD2AP expression was significantly greater in podocytes (P = 0.046) and was significantly less in proximal tubule cells (P = 0.014) in patients of group B compared with those of group A. Moreover, CD2AP expression was significantly increased in lateral tubule cells in both groups (group A, P = 0.02; group B, P = 0.001), and CatL expression in glomeruli and tubule cells did not change with the duration of CsA treatment in either patient group.

CONCLUSIONS

CD2AP expression in renal tubules may histologically associate with tissue hypoxia and reflected recovery from CsA-mediated renal injury in patients, even with mild histological features of tubulointerstitial disorder.

Influence of cyclosporine A on glomerular growth and the effect of mizoribine and losartan on cyclosporine nephrotoxicity in young rats

The aim of this study was to evaluate the influence of cyclosporine A (CsA) on glomerular growth and the effect of mizoribine (MZR) and losartan (LSAR) on CsA-induced nephropathy in young rats. Six-week-old male Sprague-Dawley rats maintained on a low salt diet were given CsA (15 mg/kg), CsA and LSRT (30 mg/kg/day), CsA and MZR (5 mg/kg), or a combination of CsA, LSRT, and MZR for 4 and 7 weeks (two experiments) and compared with control group (olive oil-treated). Histopathology and glomerular size, inflammatory and fibrotic factors were studied. The score of acute CsA toxicity significantly decreased in the CsA + MZR group compared to the CsA group (p < 0.01). MZR and MZR + LSRT reduced tubulointerstitial fibrosis and TGF-β1 mRNA expression at 7 weeks. Osteopontin (OPN) mRNA expression was decreased at 7 weeks in MZR + LSRT (p < 0.01). Glomerular area decreased CsA group and recovered in MZR (p < 0.01) and MZR + LSRT (p < 0.01) at 7weeks. This study demonstrated that MZR and LSRT had suppressive effects on inflammatory process in chronic CsA nephropathy and led to improvement of tubular damage, tubulointerstitial fibrosis and arteriolopathy by down regulation of OPN and TGF-β1 and glomerular size contraction.

Use of Cyclosporine Therapy in Steroid Resistant Nephrotic Syndrome (SRNS): A Review

A chronic, progressive disorder Steroid Resistant Nephrotic Syndrome (SRNS) accounts for 10-20% of all children with Nephrotic Syndrome. It is a heterogeneous disorder comprised of persistent edema, proteinuria, hypoalbuminemia and hyperlipidemia. Treatment for steroid-resistant nephrotic syndrome (SRNS) is challenging and children who suffer from SRNS require aggressive treatment to achieve remission. Calcineurin inhibitors have been used more in an empirical manner than on the basis of clear rationale. It was in 1984 when cyclosporine was first considered for the treatment of steroid resistant nephrotic syndrome. Cyclosporin is a calcineurin inhibitor that suppresses immune response by downregulating the transcription of various cytokine genes. Till now many studies have been conducted to determine dosages, duration of therapy, side effects and advantages of cyclosporine. Treatment of SRNS remains a difficult challenge in pediatric nephrology.  Treatment should be individualized according to the underlying histopathology, and clinical and environmental conditions of the children. There is an urgent need to distinguish as soon as possible those patients who may benefit from prolonged immunosuppressive treatment from those who will not benefit from such treatment and who will just suffer from its major side effects. The emerging evidence that the majority of genetic forms of SRNS should receive symptomatic treatment only, should also be clinically tested and studies baring its significance should be evaluated in the future.

Efficacy of cyclosporine A for steroid-resistant severe Henoch-Schönlein purpura nephritis

Aggressive treatment is necessary for continuous high-range proteinuria in cases of pediatric Henoch-Schönlein purpura nephritis (HSPN) as the long-term prognosis is sometimes poor. Cyclosporine (CyA) has immunosuppressive effects as well as a very selective inhibitory effect on T-helper cell function. Here we report two 7-year-old boys with steroid-resistant HSPN treated with CyA. After diagnosis of HSPN, we treated both patients with methylprednisolone and urokinase pulse therapy (MUT) combined with multiple drugs; however, high-range proteinuria persisted and CyA was added to the treatment regimen. The proteinuria subsequently decreased gradually and pathological findings at the second renal biopsy were improved. Furthermore, neither patient showed any adverse effects, such as hypertension, encephalopathy, or chronic nephrotoxicity, to the CyA treatment.In conclusion, these results suggest that CyA may be a safe and effective treatment for steroid-resistant severe HSPN.

Positive role of rituximab in switching from cyclosporine to mycophenolate mofetil for children with high-dose steroid-dependent nephrotic syndrome

BACKGROUND

Recent randomized studies indicate that mycophenolate mofetil (MMF) is inferior to cyclosporine (CsA) in preventing relapses of nephrotic syndrome (NS). During the last decade, rituximab (RTX) has emerged as a rescue therapy in patients with complicated, frequently relapsing, or steroid-dependent NS.

CASE-DIAGNOSIS/TREATMENT

After introducing RTX in our single center, we analyzed 26 patients with steroid-dependent NS who had relapses while receiving long-term CsA and who were subsequently switched to MMF. MMF was adjusted to maintain a targeted predose mycophenolic acid (MPA) level of 2-5 μg/ml. Moreover, for patients who required MMF and high-dose prednisolone (PSL) to maintain remission, a single infusion of RTX (375 mg/m(2)) was added. The primary endpoint was the probability of achieving PSL-free remission for >1 year. At a mean follow-up of 28.8 ± 9.9 months, 11 of 26 patients (42 %) required RTX treatment, and 22 of those patients (85 %) achieved PSL-free sustained remission. The mean predose MPA levels for patients who achieved PSL-free sustained remission were significantly higher compared with those for patients who did not (3.1 μg/ml vs. 1.7 μg/ml, p < 0.05).

CONCLUSIONS

After RTX introduction, most patients were able to switch from CsA to MMF and achieve sustained PSL-free remission.

A comparative study on renal biopsy before and after long-term calcineurin inhibitors therapy: an insight for pathogenesis of its toxicity

Calcineurin inhibitors (CNIs) are effective immunosuppressive agents for the successful treatment of childhood steroid-resistant nephrotic syndrome (SRNS). Because these patients require long-term treatment, the identification of early markers of CNI-induced nephrotoxicity (CNIN) is imperative. The monitoring of CNI trough levels, serum creatinine, and glomerular filtration rate is not an accurate marker of CNIN. The present study has been undertaken to identify early markers of CNIN in SRNS patients. Twenty-four pediatric SRNS patients were included with paired renal biopsies, before initiation (time zero biopsy) and at least 1 year after CNI therapy (protocol renal biopsy) with standard dosage. Semiquantitative morphologic grading of the histologic features was done for assessing CNIN. Immunohistochemical markers for oxidative stress (nitrotyrosine [NT]), fibrogenic cytokine (transforming growth factor β1 [TGF-β1]), and endothelial injury (endothelial nitric oxide synthase [eNOS]) were evaluated. In addition, ultrastructural study was done to assess mitochondrial injury in endothelial and tubular epithelial cells. The protocol renal biopsies in comparison with time zero biopsies showed significant increase in glomerulosclerosis, juxtaglomerular apparatus hyperplasia, tubular atrophy, interstitial fibrosis, arteriolar hyalinosis, and smooth muscle vacuolization (P < .05 - P < .001). Significantly higher immunoexpression of eNOS (91.6%), NT (71%), and TGF-β1 (87.5%) was noted in posttreatment biopsies. Mean mitochondrial injury grade among post-CNI cases in endothelial cells and proximal tubular cells was 2.28 and 1.4, whereas in pre-CNI, it was 0.28 and 0.27, respectively. We propose that immunohistochemical overexpression of NT, eNOS, and TGF-β1 is an early marker of CNIN. Endothelial and proximal tubular mitochondrial injury may play an important role in the pathogenesis of CNIN.

Efficacy of tacrolimus in the treatment of children with focal segmental glomerulosclerosis

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) is the most common glomerular condition leading to end-stage renal disease (ESRD) and the third most common cause of ESRD in pediatric patients.

METHODS

This is a retrospective study consisting of 22 pediatric patients with FSGS and heavy proteinuria. After demonstrating steroids resistance, the patients were treated with tacrolimus, targeting a trough level 5-8 ng/mL. The primary outcome is the induction of remission with tacrolimus.

RESULTS

Thirteen patients (59%) achieved remission (complete in 31.8% and partial in 27.2%) and 12 patients showed stable or improved renal function over an average follow-up of 2.9 years (range: 0.5-7 years). There was no significant difference in response rate between African American and Caucasian patients. None of the patients had significant side-effect to tacrolimus and none of the repeat biopsies showed an increase in interstitial fibrosis compared to baseline. The best renal outcome was for patients who achieved complete remission. Partially responsive patients had improved renal function compared with resistant patients.

CONCLUSION

Tacrolimus is a viable option in the treatment of children with idiopathic steroid resistant FSGS.

Synergistic protective effects of mizoribine and angiotensin II receptor blockade on cyclosporine A nephropathy in rats

BACKGROUND

Chronic cyclosporine A (CsA) nephrotoxicity is manifested by renal dysfunction, progressive histopathological kidney lesions characterized by afferent arteriolopathy, and tubulointerstitial fibrosis. In addition to the direct toxic effect of CsA, many other etiological factors such as angiotensin II, transforming growth factor (TGF)-β, and macrophage infiltration are involved in this pathogenesis. This study investigated the hypothesis that concomitant administration of mizoribine (MZR) and angiotensin II receptor blockade (ARB) may prevent CsA nephrotoxicity in rats.

METHODS

Sprague-Dawley male rats were divided into the following seven groups: group 1, treated with CsA; group 2, treated with CsA + MZR; group 3, treated with CsA + valsartan (Val); group 4, treated with CsA + MZR + Val; group 5, treated with MZR; group 6, treated with Val; and group 7, controls (n = 5 each). Renal histopathology and the effect of CsA-induced nephrotoxicity on inflammatory mediators were evaluated.

RESULTS

Results of this study demonstrated that ARB administration significantly decreased arteriolopathy and that in comparison with monotherapy, concomitant administration of MZR and ARB further decreased arteriolopathy, fibrosis, macrophage infiltration, and TGF-β1 mRNA expression associated with CsA nephrotoxicity.

CONCLUSION

These findings indicate that MZR and ARB combination treatment provides synergistic protective effects against chronic CsA nephrotoxicity.

Uncertainty in management of childhood-onset idiopathic nephrotic syndrome: is the long-term prognosis really favorable?

Despite the recent establishment of clinical practice guidelines, many areas in the management of childhood idiopathic nephrotic syndrome (INS) remain uncertain. In this edition of Pediatric Nephrology Samuel et al. report significant differences between Canadian pediatric nephrologists' practice and guideline recommendations, including initial duration of glucocorticoid treatment, choice of glucocorticoid-sparing agents in cases of frequently relapsing or steroid-dependent INS, and biopsy timing. Although evidence is emerging that the incidence of subsequent relapse can be reduced with longer initial glucocorticoid therapy, even with this new regimen relapse occurs in more than half of the children with steroid-sensitive INS. Cyclosporine (CsA) as a glucocorticoid-sparing agent for children with frequently relapsing or steroid-dependent INS is believed to provide protection from steroid toxicity and significantly improve the quality of life. However, recent follow-up studies of the post-CsA era have revealed a high incidence of INS relapse in adulthood in patients treated with CsA in childhood, and CsA use itself is a significant predictor of recurrent relapses. Therefore, pediatric nephrologists must recognize the potential of adverse effects that may appear later in life because of prolonged immunosuppressive therapy in childhood.

Novel use of rituximab for steroid-dependent nephrotic syndrome in children

BACKGROUND

Though rituximab (RTX) is effective for childhood steroid-dependent nephrotic syndrome (SDNS), an established regimen does not exist. The relapses tend to occur when the peripheral blood B-cell count re-arises at 3 months upon single RTX infusion. This study was conducted to clarify whether the long-term remission of SDNS can be obtained by repeated RTX administrations.

METHODS

RTX was administered 4 times at 3-month intervals at 375 mg/m(2)/time to 5 children with SDNS. The changes in the clinical indicators were analyzed.

RESULTS

The median (range) observation period was 6.3 (0.9-8.4) years before RTX and 3.2 (1.9-3.8) years following the commencement of RTX. The changes in the clinical indicators were as follows (median and range): (1) annual number of relapses: before administration 1.4 (1.1-3.5) times/year, after administration 0.0 (0.0-0.0) times/year, and (2) median steroid dosage: before administration 0.80 (0.23-0.96) mg/kg/day, after administration 0.00 (0.00-0.00) mg/kg/day. All changes were significant at p < 0.05. Relapse occurred 3 times following the start of RTX (the period to relapse was 2.2, 1.9, and 2.3 years, respectively). No serious side effects were seen.

CONCLUSIONS

Repeated RTX against SDNS in children may be a useful therapeutic option.

Cyclosporin A may cause injury to undifferentiated glomeruli persisting in patients with Alport syndrome

BACKGROUND/AIMS

Alport syndrome (AS) is a renal disorder caused by a genetic abnormality of type IV collagen α3 and α4, or α5 genes and shows a poor prognosis. Since the defect of type IV collagen synthesis disturbs the maturation process of the glomerular capillary loop, residual immature glomeruli persist after birth. The therapeutic efficacy of cyclosporin A (CyA) for AS patients seems to be controversial. We recently noted that renal specimens obtained from a child with AS who was treated with CyA and then developed CyA nephropathy included an increased number of undifferentiated embryonic-type glomeruli.

METHODS

We analyzed renal histologic and immunohistologic findings in children with AS who did (n = 3) or did not (n = 2) develop CyA-induced nephropathy despite appropriately low serum CyA concentrations (<100 ng/mL) being maintained over a period of 2 years. To discriminate embryonic-type from mature glomeruli, staining for type IV collagen α1, laminin β1, and laminin β2 accompanied by light microscopic observation were employed. Staining patterns were used to semiquantitatively assess glomerular immaturity (glomerular immaturity index, or GII).

RESULTS

In initial biopsy specimens, residual embryonic-type glomeruli were observed in each patient. Patients with early-onset CyA nephropathy had a high GII (median value 2.91 vs 1.23 ± 0.62 normal kidney tissues). In the follow-up biopsy after CyA treatment, surviving embryonic-type, collapsing embryonic-type, and sclerotic glomeruli that had failed to differentiate were observed. Taken together, the number of these glomeruli essentially equaled the total number of embryonic-type glomeruli in specimens obtained before CyA treatment.

CONCLUSIONS

Our findings indicate a need for caution in CyA therapy for patients with AS, even for a relatively short course of administration, because some patients may have an unexpected number of embryonic-type glomeruli that predispose to CyA nephropathy.

Calcineurin inhibitor induced nephrotoxicity in steroid resistant nephrotic syndrome

Prolonged therapy with calcineurin inhibitors (CNI) is effective in patients with difficult nephrotic syndrome. However, information on prevalence and risk factors for nephrotoxicity in children with steroid-resistant nephrotic syndrome is limited. This retrospective observational study was conducted on 40 patients with steroid-resistant nephrotic syndrome treated with cyclosporine (CyA) (n = 28) or tacrolimus (n = 12) for more than 2 years. Nephrotoxicity was defined by the presence of striped fibrosis involving ≥10% of the interstitium or nodular hyalinosis in more than one arteriole. Ten additional parameters were graded semi-quantitatively. Continuous data are presented as median and interquartile range (IQR). The median (IQR) age at onset of nephrotic syndrome and CNI therapy were 30 (21-45) and 49.5 (40-102.5) months. A second renal biopsy, following 30 (26-35) months of CNI therapy, showed histological toxicity in 10 (25%) patients. Toxicity was seen in 7 and 3 patients receiving CyA and tacrolimus, respectively, and 5 patients each with minimal change and focal segmental glomerulosclerosis. Therapy with CNI was associated with significant increases in scores for global glomerulosclerosis, tubular atrophy, interstitial fibrosis, nonnodular arteriolar hyalinosis (P < –0.001 for all), arteriolar smooth-muscle vacuolization (P = –0.02), juxtaglomerular hyperplasia (P = –0.002), and tubular microcalcinosis (P = –0.06). Risk factors for nephrotoxicity were initial resistance (OR 9; 95% CI 1.0-80.1; P = –0.049); dose of CyA (OR 9.2; 95% CI 1.1-74.6; P = –0.037); duration of heavy proteinuria (OR 1.2; 95% CI 1.0-1.4; P = –0.023); and hypertension during therapy (OR 6; 95% CI 1.3-28.3; P = –0.023). Following prolonged CNI therapy, one in four biopsies show features of toxicity. Prolonged duration of heavy proteinuria, hypertension, initial steroid resistance and high CyA dose predict the occurrence of nephrotoxicity.

Cyclosporine versus mycophenolate mofetil for maintenance of remission of steroid-dependent nephrotic syndrome after a single infusion of rituximab

The efficacy of rituximab (RTX) as the sole therapy for preventing relapses of nephrotic syndrome (NS) is transient in most patients; therefore, the optimal therapy required for maintaining a successful response to a biological agent remains a challenge. We conducted a prospective study to compare the efficacy of cyclosporine (CsA) with that of mycophenolate mofetil (MMF) as maintenance therapy after a single infusion of RTX. Of 29 patients with persistent steroid-dependent NS despite the use of CsA and/or MMF, 13 without chronic nephrotoxicity continued CsA therapy, maintaining a 2-h post-dose CsA level of 400-500 ng/ml (CsA group). The remaining 16 were treated with MMF, maintaining a pre-dose level of 2-5 μg/ml of mycophenolic acid (MMF group). The median duration of CsA and MMF treatment was 18 and 19 months, respectively. Despite the mean number of relapses before RTX treatment being significantly lower in the MMF group than in the CsA group (2.3/year vs. 4.6/year, p < 0.01), treatment failure occurred more frequently in the MMF group (7/16) than in the CsA group (2/13). The rate of sustained remission was also significantly higher in the CsA group than in the MMF group (p < 0.05).

CONCLUSION

In patients with severe steroid-dependent NS, CsA appears to be more effective than MMF for maintaining remission after a single infusion of RTX.

Survey of rituximab treatment for childhood-onset refractory nephrotic syndrome

BACKGROUND

Rituximab (RTX) is a promising option for treating childhood-onset steroid-dependent (SDNS), frequently relapsing (FRNS), and steroid-resistant (SRNS) nephrotic syndrome.

METHODS

We retrospectively surveyed RTX treatment for these conditions to evaluate its indications, efficacy and adverse events. Questionnaires were sent to 141 hospitals in Japan.

RESULTS

Seventy-four patients (52 SDNS; 3 FRNS; 19 SRNS) were treated with RTX because of resistance to various immunosuppressive agents. Most patients received a single administration of RTX (85%). Forty-one of 53 SDNS/FRNS (77%) and 5 of 17 SRNS (29%) patients successfully discontinued prednisolone (16 SDNS/FRNS and 6 SRNS achieved their first discontinuation since onset), and 17 out of 53 SDNS/FRNS patients (31%) discontinued cyclosporine. However, 28 of the 53 patients (51%) relapsed. Although immunosuppressive agents did not extend B cell depletion, relapses were significantly less if immunosuppressive agents were continued after RTX (P = 0.006; hazard ratio = 0.2). Among the SRNS patients, complete (n = 6) and partial remission (n = 6) were achieved. No life-threatening adverse events were experienced.

CONCLUSIONS

Although this was a multi-center survey where treatment of nephrotic syndrome varied between centers, the steroid-sparing effect of RTX in SDNS/FRNS was excellent. If single administration of RTX is chosen, continuation of immunosuppressive agents is recommended for prevention of relapse.

Treatment of tacrolimus or cyclosporine A in children with idiopathic nephrotic syndrome

BACKGROUND

Cyclosporine A (CsA) and tacrolimus (TAC) are often alternative treatment choices for patients with nephrotic syndrome.

METHODS

In this prospective study, the efficacy and safety of CsA and TAC in inducing and maintaining remission in 74 children with idiopathic nephrotic syndrome (INS) were evaluated.

RESULTS

In terms of short-term efficacy, TAC was more effective than CsA in children with steroid-resistant nephrotic syndrome (χ(2) = 13.75, P = 0.001), although no significant difference in number of episodes of relapse were found in patients with complete remission between the two treatment groups (first year: χ(2) = 0.261, P = 0.88; second year: χ(2) = 2.685, P = 0.26). In patients with frequently relapsing or steroid-dependent nephrotic syndrome, no significant difference in short-term remission (χ(2) = 1.908, P = 0.39) or in relapse frequency during follow-up (within first year: χ(2) = 1.046, P = 0.59; within second year: χ(2) = 0.587, P = 0.75) were found between the two groups. There was a difference in the rate of adverse effects between the two treatment groups [nephrotoxicity: 4/24 (CsA) vs .0/50 (TAC), P = 0.002; hirsutism: 8/24 (CsA) vs. 0/50 (TAC), P < 0.001].

CONCLUSIONS

In our pediatric patient cohort, the treatment of steroid-resistant nephrotic syndrome with tacrolimus was associated with higher efficacy and lower renal toxicity in comparison to CsA, although no favorable outcome in relapse rate during long-term follow-up was seen. On the other hand, tacrolimus was not always the better choice to replace CsA in the treatment of severe frequently relapsing or steroid-dependent nephrotic syndrome.

Second-line options for refractory steroid-sensitive and -resistant nephrotic syndrome

Although initially, many children with idiopathic nephrotic syndrome respond to steroid therapy, a repeated course for patients with relapses often causes significant steroid toxicity. Patients with frequent relapses or steroid dependency thus require alternative treatment, and so far, cyclophosphamide or levamisole have been regarded as first-choice options, although the latter is no longer available in many countries. Data are accumulating that mycophenolic acid may be an alternative for these patients. Calcineurin inhibitors (cyclosporine A or tacrolimus) are usually effective and are often used after cytotoxic treatment, but long-term treatment is necessary, raising concerns regarding the accumulation of side effects. Still, some patients show a tendency to relapse even on this maintenance regimen and some even have a refractory course that creates a medical dilemma. For this situation, recent data have demonstrated an effect of monoclonal antibodies directed to B cells - rituximab, a drug that may also prove to be a therapeutic option in less complicated cases. Patients that do not respond to initial steroid treatment need genetic testing and a renal biopsy, since focal segmental glomerulosclerosis may be present. Treatment options include pulse methylprednisolone, often in addition to calcineurin inhibitors (mainly cyclosporine but also, recently, tacrolimus). Cyctotoxic treatment, especially intravenous cyclophosphamide, has been found to be effective in steroid-resistant nephrotic syndrome by some studies but is inferior to calcineurin inhibitors. In addition, mycophenolic acid and rituximab have been used in children with primary focal segmental glomerulosclerosis; however, response seems to be inferior in comparison with patients with steroid-sensitive nephrotic syndrome. Taken together, idiopathic nephrotic syndrome, including steroid-sensitive as well as steroid-resistant patients, is a potentially serious disorder. Although much progress has been made in recent years and a wide arsenal of immunological interventions is available, some patients have a treatment refractory course. Prospective studies or at least standardization of treatment for complicated cases is urgently needed.

Nephrotoxicity of once-daily cyclosporine A in minimal change nephrotic syndrome

BACKGROUND

Although once-daily cyclosporine (CsA) therapy may have greater nephrotoxic-sparing effects than standard twice-daily therapy, little information is available in children with steroid-dependent minimal change nephrotic syndrome (MCNS) regarding histological analysis after long-term once-daily administration.

CASE-DIAGNOSIS/TREATMENT

A prospective study of the clinical efficacy and comparison between pre- and post-treatment renal biopsy findings in ten children (mean age, 8.8 years) with steroid-dependent MCNS who were administered once-daily CsA therapy for more than 24 months (mean ± SD, 30 ± 3.7) was performed in Saitama Children's Medical Center. Administration of once-daily CsA therapy (mean dose, 2.8 ± 0.6 mg/kg/day; mean C2 levels, 670 ± 64 ng/ml) resulted in a significant reduction in the median relapse rate from 4.6 to 0.2 times per year, and five patients did not experience a relapse of NS. Furthermore, mean threshold of prednisolone dose significantly reduced from 1.2 to 0.02 mg/kg on alternate days. However, two patients showed evidence of chronic CsA nephrotoxicity (CsAN).

CONCLUSIONS

Once-daily CsA therapy appears to be effective in children with steroid-dependent MCNS. However, follow-up renal biopsies should be performed to investigate the presence of CsAN after more than 24 months of treatment with once-daily regimen as well as with the conventional twice-daily regimen.

Complications of nephrotic syndrome

Nephrotic syndrome (NS) is one of the most common glomerular diseases that affect children. Renal histology reveals the presence of minimal change nephrotic syndrome (MCNS) in more than 80% of these patients. Most patients with MCNS have favorable outcomes without complications. However, a few of these children have lesions of focal segmental glomerulosclerosis, suffer from severe and prolonged proteinuria, and are at high risk for complications. Complications of NS are divided into two categories: disease-associated and drug-related complications. Disease-associated complications include infections (e.g., peritonitis, sepsis, cellulitis, and chicken pox), thromboembolism (e.g., venous thromboembolism and pulmonary embolism), hypovolemic crisis (e.g., abdominal pain, tachycardia, and hypotension), cardiovascular problems (e.g., hyperlipidemia), acute renal failure, anemia, and others (e.g., hypothyroidism, hypocalcemia, bone disease, and intussusception). The main pathomechanism of disease-associated complications originates from the large loss of plasma proteins in the urine of nephrotic children. The majority of children with MCNS who respond to treatment with corticosteroids or cytotoxic agents have smaller and milder complications than those with steroid-resistant NS. Corticosteroids, alkylating agents, cyclosporin A, and mycophenolate mofetil have often been used to treat NS, and these drugs have treatment-related complications. Early detection and appropriate treatment of these complications will improve outcomes for patients with NS.

Clinical evaluation of chronic nephrotoxicity of long-term cyclosporine A treatment in adult patients with steroid-dependent nephrotic syndrome

AIM

Chronic nephrotoxicity of long-term cyclosporine A (CsA) treatment is a matter of concern in patients with steroid-dependent nephrotic syndrome (SDNS).

METHODS

Twenty-eight adult NS patients (25, minimal-change nephrotic syndrome (NS); three, focal-segmental glomerulosclerosis) were divided into three groups. Group A was continuously treated with CsA for more than 5 years (143 ± 40 months, 1.3 ± 0.4 mg/kg per day at final analysis, n = 12); group B had been previously treated with CsA (70 ± 27 months, n = 6); and group C had been treated with corticosteroids alone (n = 10). The clinical variables related to chronic CsA nephrotoxicity were examined.

RESULTS

In groups A and B, estimated glomerular filtration rate decreased from 86 ± 22 and 107 ± 17 to 83 ± 23 and 88 ± 13 mL/min per 1.73 m(2) , respectively, at final analysis (both P < 0.05). Serum magnesium levels in group A were significantly lower than those in group B or C (A, 1.78 ± 0.16 mg/dL; B, 2.00 ± 0.14 mg/dL; C, 2.03 ± 0.10 mg/dL; A vs B, C, P < 0.01), and a significant correlation between these and the duration of CsA treatment was found (r = -0.68, P < 0.001). There was a trend towards a correlation between the duration of CsA administration and urinary α1-microglobulin (r = 0.38, P = 0.07).

CONCLUSION

Mild decrease in renal function and hypomagnesemia were found in adult SDNS patients with long-term CsA treatment. Careful monitoring of renal function, blood pressure and serum magnesium levels is necessary.

New therapies in steroid-sensitive and steroid-resistant idiopathic nephrotic syndrome

Although many children with idiopathic nephrotic syndrome (INS) respond initially to steroid therapy, repeated courses for patients with relapses often cause significant steroid toxicity. Patients with frequent relapses who develop steroid dependency thus require alternative treatment. The first such options have been considered to be cyclophosphamide or levamisole, although the latter is no longer available in many countries. There is also an increasing body of data indicating that mycophenolic acid (MPA) may be an alternative for these patients. Calcineurin inhibitors (cyclosporine A or tacrolimus) are usually effective and often used after cytotoxic treatment, but long-term treatment with these agents is necessary, raising concerns of a possible accumulation of side effects. Some patients show a tendency to relapse even on such maintenance regimens, and some even have a refractory course that creates a medical dilemma. For this situation, recent data indicate that monoclonal antibodies directed to B-cells (e.g. rituximab) may have some effect and that such drugs may also prove to be a therapeutic option in less complicated cases. Patients that do not respond to steroid treatment need genetic testing and a renal biopsy since focal segmental glomerulosclerosis (FSGS) may be present. Treatment options include pulse methylprednisolone, often in addition to calcineurin inhibitors, mainly in the form of cyclosporine, but tacrolimus has also come into recent favor. Some studies have found cytotoxic treatment, especially intravenous cyclophosphamide, to be effective in steroid resistant nephrotic syndrome, but it seems to be inferior to calcineurin inhibitors. MPA and rituximab have also been used in children with primary FSGS, but the response seems to be inferior to that in patients with steroid sensitive nephrotic syndrome. Taken together, INS in both steroid-sensitive and steroid-resistant patients is a potentially complicated disorder, and despite a wide arsenal of immunological interventions, some patients have a treatment refractory course. Prospective studies or at least standardized treatment for complicated cases is urgently needed.

Predictive factors for ciclosporin-associated nephrotoxicity in children with minimal change nephrotic syndrome

Aims

To identify the predictive factors for ciclosporin A (CyA)-associated nephrotoxicity (CAN) in children with minimal change nephrotic syndrome (MCNS).

Methods

The clinical and laboratory findings of 58 children (median age 3.2 years, range 1.1–13.1 years, male:female 48:10) with MCNS who were treated with CyA from 1992 to 2002 were analysed retrospectively. Forty-eight (83%) of them were steroid dependent and 10 (17%) were steroid resistant. The starting dose of CyA was 5 mg/kg per day, and the desired drug level was kept at 100–200 ng/ml. Serial renal biopsies were performed before and after CyA therapy.

Results

Twenty-two patients (38%) had CAN (group I) and 36 (62%) did not (group II). There were no differences in the age at onset, sex, initial response to steroids, duration of CyA therapy and relapse rates. However, the median CyA trough levels were significantly higher in group I than in group II (218.0±15.2 vs 171.8±6.7 ng/ml, p=0.01). Changes in creatinine clearance were more decreased in group I than in group II (−39.4±8.2 vs 2.7±4.3 ml/min per 1.73 m2, p<0.0001). Multiple logistic regression analysis also revealed the median CyA trough level was an independent risk factor for the development of CAN (OR 1.025, 95% CI 1.007 to 1.044, p=0.007).

Conclusions

The median CyA trough level was an independent and significant risk factor for the development of CAN in children with MCNS receiving moderate-dose CyA.

Single daily high-dose mizoribine therapy for children with steroid-dependent nephrotic syndrome prior to cyclosporine administration

Although cyclosporine (CsA) therapy is effective in the management of children with steroid-dependent nephrotic syndrome (SDNS), a recent study has revealed that the use of CsA itself was a significant predictor of NS relapse in adulthood. The efficacy of single daily high-dose mizoribine (MZR) therapy was assessed in 10 children with SDNS (mean age, 6.2 years) who had never been treated with CsA previously. MZR was started at 5 mg/kg, administered as a single daily dose after breakfast, and the dose was adjusted to achieve 2-h post-dose MZR levels (C2) of approximately 3 μg/ml. In 9 of the 10 patients, treatment with a single daily dose of MZR (mean dose, 8.4 mg/kg/day) over a period of 22 months (median) resulted in significant reduction of the mean prednisolone dose from 0.39 to 0.15 mg/kg/day and the median 12-month relapse rate from 3.0 to 0.4 episodes/12 months. Although cyclophosphamide was initiated in one patient because of treatment failure, none of the 10 patients required treatment with CsA during the observation period (median, 33 months). These data indicate that single daily high-dose MZR therapy is possibly useful in treating children with SDNS and that it may also eliminate the need for CsA in some patients.

Cyclosporine A - treated nephrotic children show impaired vasodilatation but no autonomic neuropathy

INTRODUCTION

The aim of the study was to determine the effect of long-term cyclosporine A (CsA) treatment in children with idiopathic nephrotic syndrome on autonomic nerve function and peripheral blood flow assessed with thermography.

MATERIAL AND METHODS

The study group consisted of 19 nephrotic children treated with cyclosporine A compared to 16 healthy children. The assessment of blood flow was made based on the results of thermographic measurements during the cold stress test by an infrared radiation registering camera. Ewing's battery of non-invasive tests was used to assess autonomic function.

RESULTS

The study showed diminished temperature increase after the cooling test in children with nephrotic syndrome treated with CsA. Sympathetic activity test results were comparable to healthy children.

CONCLUSIONS

It may be hypothesized that cyclosporine A administered even in low doses induces small vessel dysfunction measured by the thermographic method. This effect seems to be independent of sympathetic nervous system involvement, which was absent in cyclosporine A treated nephrotic children.

Single infusion of rituximab for persistent steroid-dependent minimal-change nephrotic syndrome after long-term cyclosporine

Rituximab (RTX) has been successfully used as a rescue therapy in children with steroid-dependent nephrotic syndrome (SDNS). However, little is known regarding maintenance therapy after a successful response to RTX in such patients. The efficacy and safety of a single RTX infusion (375 mg/m(2)) were assessed in ten patients who had persistent SDNS associated with minimal-change disease (MCD) despite the long-term use of cyclosporine (CsA). The mean follow-up after RTX infusion was 17 months. Applying RTX resulted in a significant reduction in the mean prednisolone (PSL) dose from 0.39 +/-0.18 to 0.15 +/- 0.14 mg/kg per day. The mean 12-month relapse rates significantly decreased from 4.1 +/- 1.7 to 0.6 +/- 0.6. All but one patient who had continued CsA as maintenance therapy after a single RTX infusion were able to withdraw from PSL without any relapses during the study period, whereas the remaining five patients who discontinued CsA experienced relapses after CD19 cells re-emerged, leading to the reintroduction of CsA or an additional RTX infusion. Infusion reactions occurred in five of ten patients. These data indicate that a single RTX infusion may improve response to CsA in patients with persistent SDNS due to the phenomenon of secondary resistance to CsA.

Cyclosporine and steroid therapy in children with steroid-resistant nephrotic syndrome

We conducted a prospective, multicenter trial to evaluate the efficacy and safety of a 12-month course of cyclosporine in children with steroid-resistant nephrotic syndrome (SRNS). Thirty-five patients were enrolled, of whom 28 had minimal change or diffuse mesangial proliferation (MC/DMP), and seven had focal segmental glomerulosclerosis (FSGS). All patients received cyclosporine and prednisolone; patients with FSGS additionally received methylprednisolone pulse therapy (MPT). The dose of cyclosporine was adjusted to maintain a trough level of 120-150 ng/ml during the initial 3 months of treatment, followed by 80-100 ng/ml during months 4-12. The primary end point was the remission rate at month 12. Remission was achieved in 23 of 28 (82.1%) patients in the MC/DMP group and in six of the seven (85.7%) patients in the FSGS group. Follow-up renal biopsies were performed in 26 patients (nine at month 12, 17 at month 24), and cyclosporine-related nephrotoxicity was detected in one (3.8%). Major adverse events comprised severe bacterial infections (two patients) and posterior reversible encephalopathy syndrome (one patient). In conclusion, a high remission rate was achieved in our patient cohort using a combined cyclosporine/ prednisolone treatment regimen in children with SRNS who had MC/DMP and a combined cyclosporine/prednisolone plus MPT regimen in children who had FSGS.

Protective effects of Mizoribine on Cyclosporine A nephropathy in rats

The therapeutic benefits of Cyclosporine A (CsA) are often limited by the chronic nephrotoxicity of its long-term use. Chronic nephrotoxicity is manifested by renal function impairment and progressive histopathological kidney lesions characterized by tubular vacuolization, tubular necrosis, interstitial fibrosis, and afferent arteriolopathy. This study tested the hypothesis that the concurrent administration of Mizoribine (MZR) may improve chronic CsA nephrotoxicity. Sprague-Dawley male rats were divided into the following four groups: group 1, control (n = 6); group 2, treated with CsA alone (n = 5); group 3, treated with CsA and MZR (n = 4); and group 4, treated with MZR alone (n = 6). The anti-inflammatory and antifibrotic effects of MZR were studied by evaluating the concentrations of the inflammatory mediator, osteopontin, renal function, and histopathology. The interstitial fibrosis was stained blue with Elastica-Massontrichrome and the sections were quantified. The CsA-treated rats showed decreased renal function and increased histologic parameters in comparison with the control rats and also showed significantly increased interstitial fibrosis area and macrophage in comparison with the control rats. The CsA MZR treatment significantly improved the interstitial fibrosis area and macrophage in comparison with the CsA-treated rats. On the basis of these findings, we suggest MZR effectively attenuates renal macrophage accumulation and the progression of interstitial fibrosis.

Risk factors for cyclosporin A nephrotoxicity in children with steroid-dependant nephrotic syndrome

BACKGROUND AND OBJECTIVES

Cyclosporin A (CsA) is a well-established treatment for steroid-dependent nephrotic syndrome (SDNS) that may, however, cause chronic ischemic renal lesions. The objective of the study was to assess the prevalence of CsA nephrotoxicity (CsAN) in protocol biopsies of children with SDNS.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

From 1990 through 2008, we performed 71 renal biopsies in 53 patients with SDNS. The mean CsA C2 levels were 466 +/- 134 ng/ml, and the mean duration of treatment was 4.7 +/- 2.0 yr before biopsy (range 2.9 to 12.7 yr).

RESULTS

CsAN was observed in 22 (31%) of 71 renal biopsies. Of these, 11 corresponded to isolated vascular or tubular lesions, and 11 corresponded to combined vascular and tubular lesions. The majority of CsAN lesions were mild (17 of 22). In no cases were lesions graded as severe. By regression analysis, CsAN was positively associated with the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) and with hyperuricemia and negatively associated with minimal-change lesions. By multivariate analysis, only association with the use of ACEIs or ARBs retained significance. Stratification of the population according to CsA C2 levels showed increased risk for CsAN for C2 levels >600 ng/ml.

CONCLUSIONS

Mild to moderate CsAN occurs in approximately one third of patients who have SDNS and are treated with CsA for >3 yr. Our data suggest that patients who require high dosages of CsA or treatment for hypertension, in particular when ACEIs/ARBs are used, are at higher risk for CsAN.

Prediction of high-degree steroid dependency in pediatric idiopathic nephrotic syndrome

Most patients with idiopathic nephrotic syndrome are steroid-responsive, but about 50% relapse and often become steroid-dependent and exposed to long-term steroid complications. The aim of this study was to determine predictive risk factors for steroid and/or cyclosporine A (CyA) dependence. In France, steroid responsiveness is defined as remission after 1 month of oral prednisone (60 mg/m(2) per day) and-in the case of persistent proteinuria on day 30-three methylprednisolone pulses (MPP; 1 g/1.73 m(2) on days 1, 3, and 5). Thirty-five steroid-responsive children, followed between 1999 and 2006, were included in this study. Median age at diagnosis was 4.9 years. All patients initially received prednisone 60 mg/m(2) per day. Twenty-four of the 35 patients were steroid-dependent, with 12 requiring MPP. Of the latter 12 patients, 83.3% were treated with CyA during follow-up; in comparison, only 16.7% of the patients who did not receive MPP required CyA during follow-up (chi-square test, P = 0.001). T risk for steroid dependence was 100% in our cohort if remission was achieved after day 20. Patients who need MPP are at high risk to require CyA to achieve disease control. By identifying these children, we could use adequate immunosuppressive drugs earlier and reduce morbidity related to steroids and multiple relapses.