Age and ethnicity affect the risk and outcome of focal segmental glomerulosclerosis

Post-transplant recurrence of focal segmental glomerular sclerosis: consensus statements

Focal segmental glomerular sclerosis (FSGS) is 1 of the primary causes of nephrotic syndrome in both pediatric and adult patients, which can lead to end-stage kidney disease. Recurrence of FSGS after kidney transplantation significantly increases allograft loss, leading to morbidity and mortality. Currently, there are no consensus guidelines for identifying those patients who are at risk for recurrence or for the management of recurrent FSGS. Our work group performed a literature search on PubMed/Medline, Embase, and Cochrane, and recommendations were proposed and graded for strength of evidence. Of the 614 initially identified studies, 221 were found suitable to formulate consensus guidelines for recurrent FSGS. These guidelines focus on the definition, epidemiology, risk factors, pathogenesis, and management of recurrent FSGS. We conclude that additional studies are required to strengthen the recommendations proposed in this review.

Causal and putative pathogenic mutations identified in 39% of children with primary steroid-resistant nephrotic syndrome in South Africa

There is a paucity of data identifying genetic mutations that account for the high rate of steroid-resistant nephrotic syndrome (SRNS) in a South African paediatric population. The aim was to identify causal mutations in genes implicated in SRNS within a South African paediatric population. We enrolled 118 children with primary nephrotic syndrome (NS), 70 SRNS and 48 steroid-sensitive NS. All children with SRNS underwent kidney biopsy. We first genotyped the NPHS2 gene for the p.V260E variant in all NS cases (n = 118) and controls (n = 219). To further identify additional variants, we performed whole-exome sequencing and interrogated ten genes (NPHS1, NPHS2, WT1, LAMB2, ACTN4, TRPC6, INF2, CD2AP, PLCE1, MYO1E) implicated in SRNS with histopathological features of focal segmental glomerulosclerosis (FSGS) in 56 SRNS cases and 29 controls; we also performed exome sequencing on two patients carrying the NPHS2 p.V260E mutation as positive controls. The overall detection rate of causal and putative pathogenic mutations in children with SRNS was 27/70 (39%): 15 (21%) carried the NPHS2 p.V260E causal mutation in the homozygous state, and 12 (17%) SRNS cases carried a putative pathogenic mutation in the heterozygous state in genes (INF2 (n = 8), CD2AP (n = 3) and TRPC6 (n = 1)) known to have autosomal dominant inheritance mode. NPHS2 p.V260E homozygosity was specifically associated with biopsy-proven FSGS, accounting for 24% of children of Black ethnicity (15 of 63) with steroid-resistant FSGS. No causal or putative pathogenic mutations were identified in NPHS1, WT1, LAMB2, PLCE1, MYO1E and ACTN4. We report four novel variants in INF2, PLCE1, ACTN4 and TRPC6.   Conclusion: We report putative missense variants predicted to be pathogenic in INF2, CD2AP and TRPC6 among steroid-resistant-FSGS children. However, the NPHS2 p.V260E mutation is a prevalent cause of steroid-resistant FSGS among Black South African children occurring in 24% of children with SRNS. Screening all Black African children presenting with NS for NPHS2 p.V260E will provide a precision diagnosis of steroid-resistant FSGS and inform clinical management. What is Known: • Limited data is available on the genetic disparity of SNRS in a South African paediatric setting. • The high rate of steroid resistance in Black South African children with FSGS compared to other racial groups is partially explained by the founder variant NPHS2 p.V260E. What is New: • We report putative missense variants predicted to be pathogenic in INF2, CD2AP and TRPC6 among steroid-resistant FSGS children. • NPHS2 p.V260E mutation remains a prevalent cause of steroid-resistant FSGS among Black South African children, demonstrating precision diagnostic utility.

Association Between NPHS2 p.R229Q and Focal Segmental Glomerular Sclerosis/Steroid-Resistant Nephrotic Syndrome

Aim

NPHS2 is the coding gene of podocin. This study aims to investigate the association between NPHS2 p.R229Q (rs61747728), the most frequently reported missense variant of NPHS2, and focal segmental glomerular sclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) based on typing the variant in a Chinese FSGS/SRNS cohort and conducting a meta-analysis.

Method

We recruited patients with FSGS or SRNS and healthy individuals. To conduct a meta-analysis, all studies on p.R229Q and FSGS/SRNS were searched from public databases.

Results

In total, we enrolled 204 patients with FSGS, 61 patients with SRNS [46 with FSGS, 9 with minimal change disease (MCD), and six patients with IgA nephropathy (IgAN)], and 100 healthy controls. Unexpectedly, p.R229Q was absent in the patients from our cohort. By meta-analysis of 21 studies including 2,489 patients with FSGS/SRNS and 6,004 healthy controls, we confirmed that the A allele of p.R229Q was significantly associated with increased risk of FSGS/SRNS (allelic OR = 1.9, 95% CI = 1.44-2.52, P < 0.001). However, the subgroup analysis showed that the association between p.R229Q and FSGS/SRNS was true only in Caucasians (allelic OR = 2.14, 95%CI = 1.54-2.98, P < 0.001) and in early-onset patients (allelic OR: 2.13, 95% CI = 1.21-3.76, P = 0.009).

Conclusion

NPHS2 p.R229Q may play an important role in enhancing the susceptibility of FSGS/SRNS, especially in ethnicity of Caucasian and age of early-onset patients.

A Life-Changing Diagnosis of Focal Segmental Glomerulosclerosis in a Young Hispanic Male

Focal segmental glomerulosclerosis is a nephrotic syndrome characterized by significant proteinuria on urinalysis and sclerosis in parts of at least one glomerulus on biopsy. While primary cases are on the rise over the past two decades, it is important to rule out etiologies that cause secondary focal segmental glomerulosclerosis such as HIV and Hepatitis B. The prevalence of this disease over the past few decades has been notably higher in men and in particular African Americans. Here, we discuss a case of a 25-year-old Hispanic man who was found to have focal segmental glomerulosclerosis after initially presenting with facial and upper and lower extremity swelling.

Changing epidemiology of nephrotic syndrome in Nigerian children: A cross-sectional study

BACKGROUND

Recent reports from small studies in West Africa suggest that Black children may have high rate of steroid sensitivity nephrotic syndrome (SSNS) contrary to long held knowledge. Herein, we determined the proportion of children with idiopathic nephrotic syndrome (INS) who achieved complete remission with steroid therapy and identified factors associated with complete remission.

METHODS

We reviewed the medical records of 241 children with INS in two centres in Lagos from 2010 to 2019. We extracted demographic data, clinical features, laboratory values at the time of diagnosis, and receipt and response to steroids and other immunosuppressants.

RESULTS

The median (interquartile range) age at diagnosis of INS was 5.1 (3.0-8.7) years and boys were 60.2% of the study population. Children with SSNS made up 85.9% (n = 207) of the study cohort. Among those aged 0-5 years, 92.6%were SSNS compared with 69.2% in those aged 11-17 years at the time of diagnosis. In addition, the proportion of children with SSNS increased from 73.8% between year 2010 and 2012 to 88.4% afterwards. Also, children with SSNS had lower serum creatinine (0.44 vs 0.70; p<0.001) and higher estimated glomerular filtration rate (101 vs 74.3 ml/min/1.73 m2; p = 0.008) at the time of diagnosis than those with steroid resistant nephrotic syndrome (SRNS).

CONCLUSION

Among Black children in Lagos, the proportion with SSNS is comparable to proportions described in children of Asian and European descent. Furthermore, children with SSNS had lower serum creatinine and higher glomerular filtration rate than those with SRNS.

Prevention and management of CVD in LMICs: why do ethnicity, culture, and context matter?

BACKGROUND

Low- and middle-income countries now experience the highest prevalence and mortality rates of cardiovascular disease.

MAIN TEXT

While improving the availability and delivery of proven, effective therapies will no doubt mitigate this burden, we posit that studies evaluating cardiovascular disease risk factors, management strategies and service delivery, in diverse settings and diverse populations, are equally critical to improving outcomes in low- and middle-income countries. Focusing on examples drawn from four cardiovascular diseases - coronary artery disease, stroke, diabetes and kidney disease - we argue that ethnicity, culture and context matter in determining the risk factors for disease as well as the comparative effectiveness of medications and other interventions, particularly diet and lifestyle interventions.

CONCLUSION

We believe that a host of cohort studies and randomized control trials currently being conducted or planned in low- and middle-income countries, focusing on previously understudied race/ethnic groups, have the potential to increase knowledge about the cause(s) and management of cardiovascular diseases across the world.

The podocin V260E mutation predicts steroid resistant nephrotic syndrome in black South African children with focal segmental glomerulosclerosis

In black African children with focal segmental glomerulosclerosis (FSGS) there are high rates of steroid resistance. The aim was to determine genetic associations with apolipoprotein L1 (APOL1) renal risk variants and podocin (NPHS2) variants in 30 unrelated black South African children with FSGS. Three APOL1 variants were genotyped and the exons of the NPHS2 gene sequenced in the cases and controls. APOL1 risk alleles show a modest association with steroid sensitive nephrotic syndrome (SSNS) and steroid resistant nephrotic syndrome (SRNS). The NPHS2 V260E variant was present in SRNS cases (V/V = 5; V/E = 4; E/E = 11), and was absent in SSNS cases. Haplotype analysis suggests a single mutation origin for V260E and it was associated with a decline in kidney function over a 60-month period (p = 0.026). The V260E variant is a good predictor of autosomal recessive SRNS in black South African children and could provide useful information in a clinical setting.

Prevalence rates of histopathologic subtypes associated with steroid resistance in childhood nephrotic syndrome in Sub-Saharan Africa: a systematic review

INTRODUCTION

The prevalence rates of the common histopathologic subtypes of childhood nephrotic syndrome associated with steroid resistance appear to be changing globally. In Sub Saharan Africa (SSA), the trend is similar over the past few decades.

AIM

This systematic review aims to determine the current prevalence rates of the histopathologic subtypes associated with childhood steroid-resistant nephrotic syndrome (SRNS) in SSA.

METHODS

A search of the PubMed, Google and African Journals Online databases was conducted from January to December 2018 using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow-chart to identify relevant articles which met the aim of the systematic review. A qualitative synthesis and descriptive analysis of the extracted data were then conducted. The mean values for the prevalence rates of the reported histopathologic subtypes were calculated. A meta-analysis was not done due to few numbers of studies reviewed. The review is registered with PROSPERO, number CRD42018111916.

RESULTS

In the West African sub-region, the currently reported histopathologic subtypes associated with childhood nephrotic syndrome are focal segmental glomerulosclerosis (FSGS), minimal-change nephropathy (MCN), membrano-proliferative glomerulonephritis (MPGN), membranous nephropathy (MN) and mesangial proliferative glomerulonephritis (MesPGN). The picture is the same in South Africa. More importantly, the predominant histopathologic lesions associated with steroid resistance are FSGS (West Africa) and MCN/FSGS (South Africa), with mean prevalence rates of 57.2% and 36.1% respectively.

CONCLUSION

The prevalence of FSGS is currently high in childhood nephrotic syndrome in SSA. This histopathologic subtype remains the commonest lesion associated with SRNS in this part of the globe.

Clinical course & management of childhood nephrotic syndrome in Germany: a large epidemiological ESPED study

Background

Nephrotic syndrome (NS) is one of the most frequent occurring chronic kidney diseases in childhood, despite its rarely occurrence in the general population. Detailed information about clinical data of NS (e.g. average length of stay, complications) as well as of secondary nephrotic syndrome (SNS) is not well known.

Methods

A nationwide ESPED follow-up study presenting the clinical course and management of children with NS in Germany.

Results

In course of 2 years, 347 children developed the first onset of NS, hereof 326 patients (93.9%) had a primary NS, and 19 patients had a SNS (missing data in 2 cases), the majority due to a Henoch-Schönlein Purpura. Patients with steroid-resistant NS (SRNS) stayed significantly longer in hospital than children with steroid-sensitive NS (25.2 vs. 13.3 d, p <  0.001). Patients with bacterial/viral infections stayed longer in hospital (24.9 d/19.5d) than children without an infection (14.2 d/14.9 d; p <  0.001; p = 0.016). Additionally, children with urinary tract infections (UTI) (p < 0,001), arterial hypertension (AH) (p < 0.001) and acute renal failure (ARF) (p < 0,001) stayed significantly longer in hospital.

Patients with SRNS had frequent complications (p = 0.004), such as bacterial infections (p = 0.013), AH (p < 0.001), UTI (p < 0.001) and ARF (p = 0.007). Children with a focal segmental glomerulosclerosis (FSGS) had significantly more complications (p = 0.04); specifically bacterial infections (p = 0.01), UTI (p = 0.003) and AH (p < 0,001). Steroid-resistance was more common in patients with UTI (p < 0.001) and in patients with ARF (p = 0.007). Furthermore, steroid-resistance (p < 0.001) and FSGS (p < 0.001) were more common in patients with AH.

Conclusions

This nationwide, largest German study presents results on the clinical course of children with NS considering a diverse range of complications that can occur with NS. The establishment of a region-wide and international pediatric NS register would be useful to conduct further diagnostic and therapy studies with the aim to reduce the complication rate and to improve the prognosis of NS, and to compare the data with international cohorts.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1233-1) contains supplementary material, which is available to authorized users.

Effect of renal function on antihypertensive drug safety and efficacy in children

BACKGROUND

Hypertension and chronic kidney disease (CKD) are common comorbidities. Guidelines recommend treating hypertension in children with CKD because it is a modifiable risk factor for subsequent cardiovascular disease. Children with CKD are frequently excluded from antihypertensive drug trials. Consequently, safety and efficacy data for antihypertensive drugs are lacking in children with CKD.

METHODS

We determined the incidence of adverse events in 10 pediatric antihypertensive trials to determine the effect of renal function on antihypertensive safety and efficacy in children. These trials were submitted to the US Food and Drug Administration from 1998 to 2005. We determined the number and type of adverse events reported during the trials and compared these numbers in participants with normal renal function and those with decreased function (defined as an estimated glomerular filtration rate [eGFR] <90 mL/min/1.73 m2 calculated using the original Schwartz equation).

RESULTS

Among the 1,703 children in the 10 studies, 315 had decreased renal function. We observed no difference between the two cohorts in the incidence of adverse events or adverse drug reactions related to study drug. Only 5 participants, all with decreased renal function, experienced a serious adverse event; none was recorded by investigators to be study drug-related. Among treated participants, children with decreased renal function who received a high dose of study drug had a significantly larger drop in diastolic blood pressure compared with children with normal renal function.

CONCLUSIONS

These data show that antihypertensive treatment in children with renal dysfunction can be safe and efficacious, and consideration should be given to their inclusion in selected drug development programs.

Nephrotic syndrome in infants and children: pathophysiology and management

Nephrotic syndrome is defined by nephrotic-range proteinuria (≥40 mg/m²/hour or urine protein/creatinine ratio ≥200 mg/mL or 3+ protein on urine dipstick), hypoalbuminaemia (<25 g/L) and oedema. This review focuses on the classification, epidemiology, pathophysiology, management strategies and prognosis of idiopathic nephrotic syndrome of childhood, and includes a brief overview of the congenital forms.

The incidence of the nephrotic syndrome in childhood in Germany

BACKGROUND

The incidence of childhood nephrotic syndrome (NS) in Germany is not well known.

METHODS

An ESPED-based nationwide collection of epidemiological data of children in 2005 and 2006.

RESULT

The mean age of NS at onset was 5.5 ± 3.7 years. The gender ratio of boys to girls was 1.8:1. The average length of stay was 15.5 ± 11.2 days, with younger children remaining significantly longer in hospital. Steroid-resistance was more common in children ≥8 years (p = 0.023). Focal-segmental glomerulosclerosis (FSGS) was more common in children >10 years (p = 0.029). The ratio of males to females with FSGS was 1:1.9, thus the FSGS risk for girls at onset was 3.3-times greater. Considering the available data, the incidence of NS in Germany is 1.2/100,000 in the population <18 years, of which 1.0/100,000 are steroid-sensitive.

CONCLUSION

Compared with international data, which primarily focused on regional and small populations, this is the largest study about the incidence of the childhood NS.

The Italian Society for Pediatric Nephrology (SINePe) consensus document on the management of nephrotic syndrome in children: Part I - Diagnosis and treatment of the first episode and the first relapse

This consensus document is aimed at providing an updated, multidisciplinary overview on the diagnosis and treatment of pediatric nephrotic syndrome (NS) at first presentation. It is the first consensus document of its kind to be produced by all the pediatric nephrology centres in Italy, in line with what is already present in other countries such as France, Germany and the USA. It is based on the current knowledge surrounding the symptomatic and steroid treatment of NS, with a view to providing the basis for a separate consensus document on the treatment of relapses. NS is one of the most common pediatric glomerular diseases, with an incidence of around 2-7 cases per 100000 children per year. Corticosteroids are the mainstay of treatment, but the optimal therapeutic regimen for managing childhood idiopathic NS is still under debate. In Italy, shared treatment guidelines were lacking and, consequently, the choice of steroid regimen was based on the clinical expertise of each individual unit. On the basis of the 2015 Cochrane systematic review, KDIGO Guidelines and more recent data from the literature, this working group, with the contribution of all the pediatric nephrology centres in Italy and on the behalf of the Italian Society of Pediatric Nephrology, has produced a shared steroid protocol that will be useful for National Health System hospitals and pediatricians. Investigations at initial presentation and the principal causes of NS to be screened are suggested. In the early phase of the disease, symptomatic treatment is also important as many severe complications can occur which are either directly related to the pathophysiology of the underlying NS or to the steroid treatment itself. To date, very few studies have been published on the prophylaxis and treatment of these early complications, while recommendations are either lacking or conflicting. This consensus provides indications for the prevention, early recognition and treatment of these complications (management of edema and hypovolemia, therapy and prophylaxis of infections and thromboembolic events). Finally, recommendations about the clinical definition of steroid resistance and its initial diagnostic management, as well as indications for renal biopsy are provided.

Ethnic Differences in Incidence and Outcomes of Childhood Nephrotic Syndrome

BACKGROUND AND OBJECTIVES

Ethnic differences in outcomes among children with nephrotic syndrome are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a longitudinal study at a single regional pediatric center comparing ethnic differences in incidence from 2001 to 2011 census data and longitudinal outcomes, including relapse rates, time to first relapse, frequently relapsing disease, and use of cyclophosphamide. Among 711 children, 24% were European, 33% were South Asian, 10% were East/Southeast Asian, and 33% were of other origins.

RESULTS

Over 10 years, the overall incidence increased from 1.99/100,000 to 4.71/100,000 among children ages 1-18 years old. In 2011, South Asians had a higher incidence rate ratio of 6.61 (95% confidence interval, 3.16 to 15.1) compared with Europeans. East/Southeast Asians had a similar incidence rate ratio (0.76; 95% confidence interval, 0.13 to 2.94) to Europeans. We determined outcomes in 455 children from the three largest ethnic groups with steroid-sensitive disease over a median of 4 years. South Asian and East/Southeast Asian children had significantly lower odds of frequently relapsing disease at 12 months (South Asian: adjusted odds ratio; 0.55; 95% confidence interval, 0.39 to 0.77; East/Southeast Asian: adjusted odds ratio; 0.42; 95% confidence interval, 0.34 to 0.51), fewer subsequent relapses (South Asian: adjusted odds ratio; 0.64; 95% confidence interval, 0.50 to 0.81; East/Southeast Asian: adjusted odds ratio; 0.47; 95% confidence interval, 0.24 to 0.91), lower risk of a first relapse (South Asian: adjusted hazard ratio, 0.74; 95% confidence interval, 0.67 to 0.83; East/Southeast Asian: adjusted hazard ratio, 0.65; 95% CI, 0.63 to 0.68), and lower use of cyclophosphamide (South Asian: adjusted hazard ratio, 0.82; 95% confidence interval, 0.53 to 1.28; East/Southeast Asian: adjusted hazard ratio, 0.54; 95% confidence interval, 0.41 to 0.71) compared with European children.

CONCLUSIONS

Despite the higher incidence among South Asians, South and East/Southeast Asian children have significantly less complicated clinical outcomes compared with Europeans.

Ethnic Differences in Childhood Nephrotic Syndrome

Nephrotic syndrome is a common glomerular disease in children with significant variability in both incidence and steroid responsiveness among various ethnic groups. The average incidence of nephrotic syndrome is 2-16.9 per 100,000 children worldwide. Understanding the variability by ethnicity may point to potential factors leading to nephrotic syndrome, which remains elusive, and may highlight factors accounting for differences in medication response. The emerging role of genetic factors associated with steroid responsive and steroid-resistant forms of nephrotic syndrome within an ethnic group can provide insight into potential biological mechanisms leading to disease. For example, among African-Americans, the risk variants in APOL1 are associated with a more than 10-fold increase in risk of focal segmental glomerulosclerosis and high-risk carriers have a twofold greater risk of progression to end-stage renal disease. Ongoing collaborative studies should consider capturing data on self-reported ethnicity to understand differences in incidence and outcomes. In the future, the availability of whole-genome data will provide an excellent opportunity for new clinical and translational research in childhood nephrotic syndrome and lead to a better understanding of the disease.

Long-term Outcomes of Childhood Onset Nephrotic Syndrome

There are limited studies on long-term outcomes of childhood onset nephrotic syndrome (NS). A majority of children with NS have steroid-sensitive nephrotic syndrome (SSNS). Steroid-resistant nephrotic syndrome (SRNS) is associated with a high risk of developing end-stage renal disease. Biomarkers and analysis of genetic mutations may provide new information for prognosis in SRNS. Frequently relapsing and steroid-dependent NS is associated with long-term complications, including dyslipidemia, cataracts, osteoporosis and fractures, obesity, impaired growth, and infertility. Long-term complications of SSNS are likely to be under-recognized. There remain many gaps in our knowledge of long-term outcomes of childhood NS, and further study is indicated.

Renal and Cardiovascular Morbidities Associated with APOL1 Status among African-American and Non-African-American Children with Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

African-American (AA) children with focal segmental glomerulosclerosis (FSGS) have later onset disease that progresses more rapidly than in non-AA children. It is unclear how APOL1 genotypes contribute to kidney disease risk, progression, and cardiovascular morbidity in children.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS

We examined the prevalence of APOL1 genotypes and associated cardiovascular phenotypes among children with FSGS in the Chronic Kidney Disease in Children (CKiD) study; an ongoing multicenter prospective cohort study of children aged 1-16 years with mild to moderate kidney disease.

RESULTS

A total of 140 AA children in the CKiD study were genotyped. High risk (HR) APOL1 genotypes were present in 24% of AA children (33/140) and were associated with FSGS, p < 0.001. FSGS was the most common cause of glomerular disease in children with HR APOL1 (89%; 25/28). Of 32 AA children with FSGS, 25 (78%) had HR APOL1. Compared to children with low risk APOL1 and FSGS (comprising 36 non-AA and 7 AA), children with HR APOL1 developed FSGS at a later age, 12.0 (IQR: 9.5, 12.5) vs. 5.5 (2.5, 11.5) years, p = 0.004, had a higher prevalence of uncontrolled hypertension (52 vs. 33%, p = 0.13), left ventricular hypertrophy (LVH) (53 vs. 12%, p < 0.01), C-reactive protein > 3 mg/l (33 vs. 15%, p = 0.12), and obesity (48 vs. 19%, p = 0.01). There were no differences in glomerular filtration rate, hemoglobin, iPTH, or calcium-phosphate product.

CONCLUSION

AA children with HR APOL1 genotype and FSGS have increase prevalence of obesity and LVH despite a later age of FSGS onset, while adjusting for socioeconomic status. Treatment of obesity may be an important component of chronic kidney disease and LVH management in this population.

Frequency and clinicopathological correlations of histopathological variants of pediatric idiopathic focal segmental glomerulosclerosis

There is no information on the frequency and clinicopathological correlations of the histopathological variants of primary focal segmental glomerulosclerosis (FSGS) in children presenting with idiopathic nephrotic syndrome (INS) in Pakistan. All consecutive children (≤17 years) who presented with INS, and in whom the histological diagnosis of FSGS was made on renal biopsies, were included in this prospective study. Their clinical, laboratory, and histopathological features at the time of presentation were noted from the case files and the biopsy reports for analysis and clinicopathological correlations. Out of 138 children, 93 (67.4%) were males and 45 (32.6%) were females. The mean age was 8.95 ± 4.14 (range: 1.5-17) years. All had NS, with steroid dependant NS (SDNS) in 45 (32.6%) and steroid resistant NS (SRNS) in 93 (67.4%) cases. Renal dysfunction at the time of presentation was found in six (4.3%) children. Global glomerulosclerosis was found in 68 (49.3%) cases. The mean number of glomeruli involved by segmental scarring was 2.98 ± 2.44. FSGS, not otherwise specified (NOS) was the most prevalent variant, comprising 89.1% of all cases. Collapsing variant comprised 8%, tip variant 1.4%, perihilar 0.7%, and cellular 0.7%. Hyaline arteriolosclerosis was found in 13 (9.4%) cases. Mild interstitial fibrosis/tubular atrophy was found in 95 (68.6%) cases, moderate in 18 (13%), and severe in two (1.4%) cases. In conclusion, FSGS, NOS variant was the highly prevalent variant, while collapsing type was also found in small but significant number of cases. Remaining three variants were distinctly rare in our children.

The expression of cytoskeletal proteins in kidney specimens of children with primary focal segmental glomerulosclerosis

Several studies have evaluated cytoskeletal proteins as prognostic factors for some types of nephrotic syndrome. However, studies concerning children with FSGS are scarce. This study was done to evaluate the glomerular, tubular, and interstitial expression of vimentin, desmin, and alpha smooth muscle actin (α-SMA) in kidney specimens of children with FSGS. Clinical and histologic data of 31 children with FSGS were reviewed. Thirty one formalin-fixed, paraffin-embedded kidney biopsy sections (3 μm) were selected for immunohistochemical staining. Double immunohistochemistry using a microwave-based two-color staining was applied. The mean age at onset in male and female was 56.3 ± 41.4 and 78.0 ± 60.4 months, respectively. The duration of follow-up was 46.3 ± 56.5 months. Interstitial fibrosis and tubular atrophy were reported in 42% and 54% of the patients, respectively. The latest evaluated mean blood pressure was significantly correlated with the expression of both vimentin and α-SMA in the interstitium (P < 0.05). However, we were not able to demonstrate any cytoskeletal protein expression as an independent predictor for renal survival. Further studies with larger sample size and longer follow-up periods are warranted to investigate the prognostic values of other histopathologic features in pediatrics with FSGS.

Pathology of idiopathic nephrotic syndrome in children: are the adolescents different from young children?

BACKGROUND

There is no specific data on the pathological lesions underlying idiopathic nephrotic syndrome (INS) in adolescents in Pakistan. Moreover, it is not known whether the pathological lesions in adolescents differ significantly from young children with INS in our setup. Materials and methods. A retrospective analysis was carried out on all patients with INS with onset ≤ 18 years of age. They were split into two groups: patients with onset of INS ≤ 12 years (young children group) and patients with onset ≥ 13 through 18 years of age (adolescent group). Renal biopsies were evaluated by light microscopy, immunoflourescence and electron microscopy. The histopathological lesions on renal biopsies were analyzed and compared between the two groups.

RESULTS

The adolescents comprised 173 (32.1%) patients, and there were 365 young children (67.8%). The mean age of adolescents at the time of onset of INS was 15.12 ± 1.5 years and there were 113 boys (65.3%) and 60 girls (34.6%). The mean age of young children was 7.26 ± 3.24 years and there were 231 boys (63.2%) and 134 girls (36.7%). Focal segmental glomerulosclerosis was the most common histopathological lesion in adolescents (36.4%) followed by minimal change disease (MCD) (28.9%). Adolescent-onset INS had a significantly higher frequency of membranous glomerulonephritis and membranoproliferative glomerulonephritis (MPGN) (P < 0.05) and significantly lower frequency of MCD (P < 0.05) than early childhood-onset INS.

CONCLUSIONS

Our data indicate that the pathological lesions in adolescent INS are different from younger children and resemble more closely those seen in adults. Our findings are concordant with the few previously published studies on this subject.

Methods for characterizing differences in longitudinal glomerular filtration rate changes between children with glomerular chronic kidney disease and those with nonglomerular chronic kidney disease

The rate of decline of glomerular filtration rate (GFR) in children with chronic kidney disease (CKD) can vary, even among those with similar diagnoses. Classic regression methods applied to the log-transformed GFR (i.e., lognormal) quantify only rigid shifts in a given outcome. The generalized gamma distribution offers an alternative approach for characterizing the heterogeneity of effect of an exposure on a positive, continuous outcome. Using directly measured GFR longitudinally assessed between 2005 and 2010 in 529 children enrolled in the Chronic Kidney Disease in Children Study, the authors characterized the effect of glomerular CKD versus nonglomerular CKD diagnoses on the outcome, measured as the annualized GFR ratio. Relative percentiles were used to characterize the heterogeneity of effect of CKD diagnosis across the distribution of the outcome. The rigid shift assumed by the classic mixed models failed to capture the fact that the greatest difference between the glomerular and nonglomerular diagnosis' annualized GFR ratios was in children who exhibited the fastest GFR declines. Although this difference was enhanced in children with an initial GFR level of 45 mL/minute/1.73 m(2) or less, the effect of diagnosis on outcome was not significantly modified by level. Generalized gamma models captured heterogeneity of effect more richly and provided a better fit to the data than did conventional lognormal models.

Antroquinonol reduces oxidative stress by enhancing the Nrf2 signaling pathway and inhibits inflammation and sclerosis in focal segmental glomerulosclerosis mice

Oxidative stress, inflammation, and fibrosis are involved in the development and progression of focal segmental glomerulosclerosis (FSGS), a common form of idiopathic nephrotic syndrome that represents a therapeutic challenge because it has a poor response to steroids. Antroquinonol (Antroq), a purified compound, is a major active component of a mushroom, namely Antrodia camphorata, that grows in the camphor tree in Taiwan, and it has inhibitory effects on nitric oxide production and inflammatory reactions. We hypothesized that Antroq might ameliorate FSGS renal lesions by modulating the pathogenic pathways of oxidative stress, inflammation, and glomerular sclerosis in the kidney. We demonstrate that Antroq significantly (1) attenuates proteinuria, renal dysfunction, and glomerulopathy, including epithelial hyperplasia lesions and podocyte injury; (2) reduces oxidative stress, leukocyte infiltration, and expression of fibrosis-related proteins in the kidney; (3) increases renal nuclear factor E2-related factor 2 (Nrf2) and glutathione peroxidase activity; and (4) inhibits renal nuclear factor-κB (NF-κB) activation and decreases levels of transforming growth factor (TGF)-β1 in serum and kidney tissue in a mouse FSGS model. Our data suggest that Antroq might be a potential therapeutic agent for FSGS, acting by boosting Nrf2 activation and suppressing NF-κB-dependent inflammatory and TGF-β1-mediated fibrosis pathways in the kidney.

Immunosuppression and renal outcome in congenital and pediatric steroid-resistant nephrotic syndrome

BACKGROUND AND OBJECTIVES

Mutations in podocyte genes are associated with steroid-resistant nephrotic syndrome (SRNS), mostly affecting younger age groups. To date, it is unclear whether these patients benefit from intensified immunosuppression with cyclosporine A (CsA). The aim of this study was to evaluate the influence of podocyte gene defects in congenital nephrotic syndrome (CNS) and pediatric SRNS on the efficacy of CsA therapy and preservation of renal function.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

Genotyping was performed in 91 CNS/SRNS patients, irrespective of age at manifestation or response to CsA.

RESULTS

Mutations were identified in 52% of families (11 NPHS1, 17 NPHS2, 11 WT1, 1 LAMB2, 3 TRPC6). Sixty-eight percent of patients with nongenetic SRNS responded to CsA, most of them achieved complete remission. In contrast, none of the patients with genetic CNS/SRNS experienced a complete remission and only two (17%) achieved a partial response, both affected by a WT1 mutation. Preservation of renal function was significantly better in children with nongenetic disease after a mean follow-up time of 8.6 years (ESRD in 29% versus 71%).

CONCLUSIONS

The mutation detection rate in our population was high (52%). Most patients with genetic CNS/SRNS did not benefit from CsA with significantly lower response rates compared with nongenetic patients and showed rapid progression to end-stage renal failure. These data strongly support the idea not to expose CNS/SRNS patients with inherited defects related to podocyte function to intensified immunosuppression with CsA.

Primary focal segmental glomerulosclerosis in Egyptian children: a 10-year single-centre experience

Primary focal segmental glomerulosclerosis (FSGS) in children accounts for 7-20% of all cases of idiopathic nephrotic syndrome (NS). To evaluate the clinical course of children with primary FSGS, the records of 72 patients with biopsy-proven FSGS admitted between 1995 and 2008 were retrospectively analysed. Forty-eight patients were male (66.7%). The mean age at presentation was 76.5 +/- 54 (range 12-192) months. The mean duration of follow-up was 76.3 +/- 42 (range 9-156) months. Seventeen patients (23.6%) presented with gross haematuria at initial presentation, 15 (20.8%) presented with hypertension and 10 patients (14%) presented with chronic renal insufficiency (CRI). The initial response to oral prednisolone was steroid resistance in 63 patients (87.5%) and steroid dependence in 4 patients (5%), while 5 patients (6.9%) were biopsied from the start because of atypical presentation. According to pathological classification, there were the tip variant (2%), collapsing variant (6%), perihilar variant (7%) and NOS (not otherwise specified; 85%). At the last clinical visit, 12 patients (16.7%) were in complete remission and 11 (15.3%) had progressed to CRI. Renal survival rates at 5 and 10 years were 93% and 68%, respectively. In conclusion, in this study we had a low percentage of FSGS, and fewer patients presenting with gross haematuria and hypertension compared with previous reports. In addition, the short-term overall renal survival seems to be better in our cohort.

Mycophenolate mofetil therapy for children with steroid-resistant nephrotic syndrome

Treating children with steroid-resistant nephrotic syndrome (SRNS) has been a clinical challenge for pediatricians. We recruited 24 children (18 boys and six girls) with steroid-resistant idiopathic nephrotic syndrome (SRINS) who were <2 years. All patients were administered prednisone 2 mg/kg per day prior to mycophenolate mofetil (MMF). By the end of the eighth week, MMF was initiated at 25-30 mg/kg daily for 6- 12 months. Prednisone dose was reduced stepwise. Biochemical assays were performed every 2 months. Complete remission was achieved in 15 patients, partial remission in six, and no response to MMF was noted in three. With MMF treatment, the levels of urinary protein and serum cholesterol decreased and that of serum albumin increased in a time-dependant manner. We demonstrated the MMF could reduce proteinuria in SRINS children <2 years. Our study suggests that MMF therapy might be an effective strategy for treating SRINS in children <2 years.

Management patterns of childhood-onset nephrotic syndrome

As an initial effort to identify opportunities to improve the management of children with nephrotic syndrome, the goal of this study was to assess the present-day management of children with primary nephrotic syndrome. A web-based survey was designed to assess the current management styles of all pediatric nephrology faculties at ten participating institutions. Ninety-one percent completed the initial survey. The duration of initial glucocorticoid therapy ranged from 4 to 24 weeks. Physicians reported that the recommendation for kidney biopsy was dependent on the response to initial corticosteroid therapy, with the minority always recommending a biopsy for frequently relapsing or steroid-dependent cases. All responding physicians recommended a kidney biopsy in steroid-resistant cases. Treatment strategies were reported to vary based upon the steroid response pattern and, where available, kidney histopathology. Striking variations in therapeutic preferences were described when alternatives to glucocorticoids were considered. The variability of management practices among pediatric nephrologists in the USA combined with the changing characteristics of our pediatric population raise concerns about our future strategies for improving healthcare for children coping with nephrotic syndrome. This variability is not unique to children's healthcare or to nephrology. However, a systematic approach to patient care and improvement in health outcomes has been shown to substantially improve morbidity and mortality outcomes in children with chronic health conditions.

Identification of common genetic variants that account for transcript isoform variation between human populations

In addition to the differences between populations in transcriptional and translational regulation of genes, alternative pre-mRNA splicing (AS) is also likely to play an important role in regulating gene expression and generating variation in mRNA and protein isoforms. Recently, the genetic contribution to transcript isoform variation has been reported in individuals of recent European descent. We report here results of an investigation of the differences in AS patterns between human populations. AS patterns in 176 HapMap lymphoblastoid cell lines derived from individuals of European and African ancestry were evaluated using the Affymetrix GeneChip Human Exon 1.0 ST Array. A variety of biological processes such as response to stimulus and transcription were found to be enriched among the differentially spliced genes. The differentially spliced genes also include some involved in human diseases that have different prevalence or susceptibility between populations. The genetic contribution to the population differences in transcript isoform variation was then evaluated by a genome-wide association using the HapMap genotypic data on single nucleotide polymorphisms (SNPs). The results suggest that local and distant genetic variants account for a substantial fraction of the observed transcript isoform variation between human populations. Our findings provide new insights into the complexity of the human genome as well as the health disparities between the two populations.

Low prevalence of NPHS2 mutations in African American children with steroid-resistant nephrotic syndrome

In African American (AA) children, focal segmental glomerulosclerosis (FSGS) is the leading cause of nephrotic syndrome (NS). It has been shown that AA children suffer from FSGS and steroid-resistant nephrotic syndrome (SRNS) at a higher frequency and with a more severe renal outcome in comparison with Caucasian children. Previous mutation analysis of large cohorts revealed that a high percentage of childhood SRNS is monogenic and that mutations in podocin (NPHS2) and Wilms' tumor gene 1 (WT1) account for approximately 30% of SRNS in children. To test whether AA children with SRNS have a similar or a higher mutation rate, we performed mutation analysis of NPHS2 and WT1 in a cohort of AA children with SRNS. Direct sequencing was carried out for all exons of NPHS2 and for exons 8 and 9 of WT1. We ascertained 18 children of AA descent in whom renal biopsy findings showed FSGS in 13 patients (72%) and minimal-change disease in five patients (28%). In both NPHS2 and WT1, no disease-causing mutations were detected. Our data strongly suggest that in AA children with SRNS, the frequency of NPHS2 mutations is much lower than in large cohorts of pediatric SRNS patients in the general population. Knowledge of mutation rate of NPHS2 in different populations of SRNS patients facilitates the physician in planning a suitable genetic screening strategy for patients.

Ethnic disparity in outcomes for pediatric peritoneal dialysis patients in the ESRD Clinical Performance Measures Project

Ethnicity information was collected for all pediatric peritoneal dialysis patients from the End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) Project for the period October 2004 through March 2005. Associations between intermediate outcomes and Hispanic ethnicity were determined. Thirty percent (207/696) of patients in the final cohort were Hispanic, 24% (165/696) non-Hispanic black, and 46% (324/696) non-Hispanic white. Hispanics were more likely to be female, older, and have a lower mean height standard deviation score (SDS). There were no significant differences among ethnic/racial groups regarding clearance parameters. More Hispanics had a mean hemoglobin > or = 11 g/dl compared with non-Hispanic blacks and non-Hispanic whites (77% vs. 55% and 70%, P < 0.0001). More Hispanics compared with non-Hispanic blacks and non-Hispanic whites had a mean serum albumin > or = 4.0/3.7 g/dl [bromcresol green/bromcresol purple laboratory method (BCG/BCP)] (50% vs. 24% and 27%, respectively, P < 0.0001). In multivariate analyses, Hispanics remained significantly more likely to achieve a mean serum albumin > or = 4.0/3.7 g/dl (BCG/BCP) compared with non-Hispanic whites (referent) and were as likely to achieve clearance and hemoglobin targets. Pediatric Hispanic peritoneal dialysis patients experience equivalent or better intermediate outcomes of dialytic care compared with non-Hispanics. Further study is needed to understand associations of Hispanic ethnicity with outcomes such as hospitalization, transplantation, and mortality.

Focal and segmental glomerulosclerosis in children: a longitudinal assessment

Recent data suggest that the histologic finding of focal and segmental glomerulosclerosis (FSGS) is increasing among children. There are, however, limited longitudinal pediatric data on prevalence, demographics, and steroid responsiveness in FSGS. We identified 201 consecutive nephrotic children diagnosed between 1977 and 2002 with 2 years follow-up; 51% had undergone renal biopsy due to steroid sequelae or resistance; 48 children with FSGS were diagnosed. Compared with non-FSGS children, FSGS children were older at diagnosis (6.9 years vs 4.4 years, P<0.02), more likely girls (54% vs 28%, P<0.02), Black or Hispanic (42% vs 16%, P<0.001), and the FSGS was more likely to be steroid resistant (73% vs 10%, P<0.001). To assess for longitudinal differences, we grouped children by presentation: pre-1985, between 1985 and 1995, and post-1995. There was no difference in proportion of children biopsied or diagnosed with FSGS during each interval. Among FSGS children, there was no difference in racial or gender composition in each period, but there was a difference in age at diagnosis (2.6 vs 5.7 vs 8.5 years; P=0.01), also observed in the non-FSGS children (2.2 vs 3.9 vs 4.9 years; P=0.02). In contradistinction to non-FSGS children, there was a marked increase in steroid resistance with FSGS (43% vs 62% vs 86%; P=0.03).

Presenting features and short-term outcome according to pathologic variant in childhood primary focal segmental glomerulosclerosis

BACKGROUND

This was a retrospective analysis of children in one center who had primary (idiopathic) FSGS.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

There were 41 patients: 34.1% female, 65.9% male, 80.5% black, and 19.5% white. At presentation, the mean age was 10.9 +/- 0.9 yr. The mean time of follow-up was 3.9 +/- 0.5 yr.

RESULTS

During the observation period, the systolic BP (SBP) and diastolic BP (DBP) remained stable, serum albumin rose slightly, and the GFR was stable. Among those who received corticosteroids at presentation, 21.2% were steroid sensitive. At last follow-up among all patients, 71% were in remission, 78% had stage 1 or 2 chronic kidney disease, and 4.9% had reached ESRD. At last follow-up, the GFR was significantly higher (P = 0.01) in patients who were initially steroid sensitive. Ethnicity had no effect on clinical data or response to therapy. The pathologic variants were as follows: Cellular, 32%; collapsing, 24%; and not otherwise specified (NOS), 44%. The chronicity scores were as follows: Cellular, 4.3; collapsing 6.4; and NOS, 4.0 (significantly higher, P = 0.02, in collapsing versus NOS). At presentation, SBP (P = 0.03) and DBP (P = 0.03) were significantly higher and GFR was lower (P = 0.03) in patients with the collapsing compared with NOS variant. Remission after the initial course of corticosteroids was less common with the collapsing variant. At last follow-up, SBP (P = 0.02) and DBP (P = 0.04) were significantly higher in patients with the collapsing versus NOS variant.

CONCLUSIONS

The short-term outcome in pediatric primary FSGS is generally favorable, but a more guarded prognosis exists for patients with collapsing FSGS.

Primary focal segmental glomerular sclerosis in children: clinical course and prognosis

To review the clinical course and identify prognostic factors, we retrospectively analyzed 92 children with steroid-resistant primary focal segmental glomerulosclerosis (FSGS). The mean age of onset was 80.4+/-42.4 months. The mean follow-up duration was 98.2+/-63.3 months. Eighty-five patients presented with nephrotic syndrome and seven presented with asymptomatic proteinuria. Thirty-three patients were initial responders to steroid treatment (late non-responders) and 59 were initial nonresponders. At last follow-up, 36 patients (39.1%) were in complete remission, and 29 (31.5%) progressed to chronic renal failure (CRF). Renal survival rates at 5, 10, and 15 years were 84, 64, and 53%, respectively. By morphological classification, there were tip variants (6.1%), collapsing variants (10.6%), cellular variants (1.5%), perihilar variants (9.1%), and NOS (not otherwise specified, 72.7%). Among the variants, there were no significant differences in age of onset, degree of proteinuria, response to treatment, or progression to CRF. Poor prognostic factors for CRF included: asymptomatic proteinuria at presentation, initial renal insufficiency, higher segmental sclerosis (%), severe tubulointerstitial change, initial nonresponse, and absence of remission. In the multivariate analysis, an increase in the initial serum creatinine and resistance to treatment were independent risk factors for CRF. A more prolonged use of corticosteroid therapy and early introduction of cyclosporin A (CsA) may improve the prognosis for primary FSGS in patients with initial steroid nonresponsiveness.

Angiotensin converting enzyme gene polymorphisms do not predict the course of idiopathic nephrotic syndrome in Swiss children

AIM

Contradictory reports exist about a correlation of angiotensin I converting enzyme (ACE) gene polymorphisms to the outcome of idiopathic nephrotic syndrome (INS) in children. We investigated the frequency of ACE polymorphisms and their impact on the clinical course of INS in children in a Swiss hospital.

METHODS

The ACE gene polymorphism (I, insertion; D, deletion) was assessed in 32 children - 22 with steroid-sensitive INS and 10 with steroid-resistant INS - with a median age at onset of INS of 2.9 years (range 1.1-15.0). Polymerase chain reaction amplification was performed on genomic DNA isolated from blood leucocytes. Results were correlated to clinical course and renal morphology.

RESULTS

The ACE genotype was I/I, I/D and D/D in two, 12 and eight patients, respectively, with steroid-sensitive INS, and in one, eight and one patient, respectively, with steroid resistance. Renal morphology, available in 25 patients showed minimal change glomerulopathy in 17 patients (14 steroid-sensitive; three steroid-resistant) and focal segmental glomerulosclerosis in eight (one steroid-sensitive; seven steroid-resistant). There was no significant correlation between ACE genotype and steroid responsiveness, histology or outcome. ACE genotype was I/I, I/D and D/D in none, 12 and five patients, respectively, with minimal change glomerulopathy, and in one, five and two patients, respectively, with focal segmental glomerulosclerosis. Six patients with steroid-resistant nephrotic syndrome went into end stage renal disease; ACE genotype was I/I in one and I/D in five, but none were D/D.

CONCLUSION

In contrast to previous reports, ACE gene polymorphism is irrelevant for clinical outcome, steroid responsiveness or morphology in Swiss children with INS.

Effect of fosinopril in children with steroid-resistant idiopathic nephrotic syndrome

We aimed to test if fosinopril reduces urinary protein excretion and alleviates renal tubular damage in normotensive children with steroid-resistant idiopathic nephrotic syndrome (SRINS). We also aimed to evaluate whether there are changes in steady-state blood pressure and serum concentrations of serum angiotensin-converting enzyme (ACE) and plasma renin activity or angiotensin II (AT-II) in children under this treatment. Forty-five normotensive patients with SRINS were randomly divided into two groups. Group I was treated with fosinopril and prednisone for 12 weeks, while group II was treated with prednisone alone for the same duration. The values of 24-h urinary protein excretion were 1.25+/-0.64 vs 2.52+/-0.56 g/24 h (P<0.05), 1.16+/-0.45 vs 2.42+/-0.24 g/24 h (P<0.05), and 1.10+/-0.41 vs 2.05+/-0.46 g/24 h (P<0.05) in group I and group II patients, respectively, at 4, 8, and 12 weeks. Patients in group I showed lower serum concentrations of urinary retinol-binding protein and beta(2)-microglobulin (P<0.01) at the end of the study, but the patients' blood pressure and components of the renin-angiotensin system (RAS) had no change during treatment. The result suggested that fosinopril significantly reduced proteinuria and alleviated renal tubular damage, but did not influence blood pressure and components of systemic RAS in normotensive children with SRINS.

Predictive factors of chronic kidney disease in primary focal segmental glomerulosclerosis

Renal histological features of focal segmental glomerulosclerosis (FSGS) are found in 75% of pediatric patients with steroid-resistant nephrotic syndrome. In order to evaluate the predictive factors of chronic kidney disease (CKD), we retrospectively reviewed the records of 110 children with biopsy-proven FSGS admitted between 1972 and 2004. Renal survival was analyzed by the Kaplan-Meier method and Cox's regression model. Two multivariate models were developed: (1) from the onset of symptoms to the occurrence of CKD and (2) from the time of renal biopsy to CKD. Mean follow-up time was 10 years [standard deviation ((SD) 5.5], and 24 patients (21.8%) progressed to CKD. At baseline, after adjustment three variables remained as independent predictors of CKD: age >6.5 years (RR=3.3, 95% CI=1.3-7.8), creatinine >1 mg/dl (RR=2.5, 95% CI=0.97-6.5), and non-response to steroids (RR=7.3, 95% CI=2.7-19.7). In a model with continuous variables only age and non-response to steroids were associated with CKD. At the time of renal biopsy, after adjustment two variables remained as independent predictors of CKD: hematuria (RR=3.0, 95% CI=1.2-7.3) and creatinine >0.8 mg/dl (RR=4.3, 95% CI=1.7-10.6). In a model with continuous variables four factors predicted CKD: age, creatinine, hematuria, and percentage of global sclerosis.

Clinical course of 110 children and adolescents with primary focal segmental glomerulosclerosis

The purpose of this retrospective cohort study was to report the clinical course of children and adolescents with primary focal segmental glomerulosclerosis (FSGS). The records of 110 patients with biopsy-proven FSGS admitted between 1972 and 2004 were retrospectively reviewed. Demographic, clinical and laboratory data were recorded and histopathological data were reanalyzed by one pathologist who had no information about the outcome of the patients. Renal survival analysis was performed using the Kaplan-Meier method. Differences between subgroups (response to corticosteroids) were assessed by the two-sided log rank test. The median age at admission was 5 years (range: 1-15 years). Forty-two patients (38.2%) presented with hematuria at admission, and 55 (50%) presented blood pressure levels above the 95th percentile. Mean follow-up time was 10 years (SD 5.5). Twenty-four patients (21.8%) presented chronic kidney disease (CKD). It was estimated that the probability of CKD was 8% at 5 years, 17% at 10 years, and 32% at 15 years after diagnosis of nephrotic syndrome. In conclusion, on the basis of the clinical and histological characteristics observed, apparently our cohort of idiopathic FSGS is comparable with other published series. However, the long-term overall renal survival seems to be better in our cohort.

High incidence of initial and late steroid resistance in childhood nephrotic syndrome

BACKGROUND

Conventional wisdom states that greater than 80% of children with nephrotic syndrome (NS) respond to steroid treatment, remain steroid-sensitive during subsequent relapses, and consequently have a favorable long-term prognosis. In contrast, steroid resistance is believed to be associated with a high risk of developing chronic renal failure. Recent reports suggest that the histologic pattern of NS in children may be changing, but whether the change is accompanied by a parallel change in steroid sensitivity is unknown.

METHODS

Initial and subsequent steroid responsiveness was evaluated in all children aged 1 to 18 years who presented with newly diagnosed NS to the 2 pediatric nephrology referral centers in southeastern Louisiana between 1994 and 2003. NS was defined as presence of edema, heavy proteinuria, and serum albumin concentration below 2.5 g/dL. Steroid sensitivity (SS) was defined as total resolution of proteinuria and edema, and partial response to steroids (PR) was defined as loss of edema with continuing proteinuria.

RESULTS

There were 210 new cases of NS. Forty-one patients (20%) had immune complex glomerulonephritis. Six patients were excluded because of incomplete data availability. Of the remaining 163 patients, 115 (71%) were SS and 23 (14%) achieved PR during the initial 4 weeks of treatment; 25 (15%) were steroid-resistant (SR). Follow-up data were available for 91 of the 115 initially SS patients; 19 subsequently became steroid-resistant. Thus, at least 45% of the patients with new-onset NS did not have typical childhood steroid-responsive NS. Initial steroid resistance was more likely in African American children and in children with older age at onset (11.5 vs. 4.6 years). Development of steroid resistance after initial SS was associated with shorter interval to the first relapse (2.2 vs. 5.4 months) and having the first relapse during the initial steroid treatment.

CONCLUSION

Compared to previous reports, our results show a higher incidence of initial and subsequent steroid resistance, characteristics not consistent with typical minimal change NS with a benign prognosis. The results suggest that in the current era, NS in children may not be as benign as indicated by earlier studies.

Mycophenolate mofetil therapy in frequently relapsing steroid-dependent and steroid-resistant nephrotic syndrome of childhood: current status and future directions

Clinicians are often faced with therapeutic dilemmas and challenges while treating children with frequently relapsing steroid-dependent nephrotic syndrome (SDNS) and steroid-resistant nephrotic syndrome (SRNS). In the past, children with SDNS have been treated with long-term alternate day steroids cyclophosphamide, cyclosporine (CSA), chlorambucil, levamisole, and azathioprine. The essential aim of these therapies is to maintain remission while limiting exposure to steroids. These medications have variable efficacy and undesirable toxicity profiles. Recently, mycophenolate mofetil (MMF) has emerged as a new therapeutic option for the management of SDNS in a few uncontrolled clinical trials. Preliminary data are encouraging. MMF was found to be useful in maintaining remission and has a steroid-sparing effect. Clearly, more data are needed to further characterize the safety and efficacy of MMF, define adequate length of treatment, and optimize drug exposure and monitoring. The management of SRNS is primarily aimed at decreasing proteinuria and inducing remission, if possible. By doing so, one would aim to preserve renal function. CSA therapy is known to be useful in this regard but has undesirable side effects, the most concerning being nephrotoxicity. MMF in combination with steroids and angiotensin-converting enzyme-inhibitor drugs is known to have some efficacy in the management of SRNS. These preliminary data have prompted the National Institutes of Health to sponsor a multicentric controlled trial to compare the safety and efficacy of MMF with that of CSA in the treatment of steroid-resistant focal segmental glomerulosclerosis (FSGS). If MMF therapy is found to be efficacious, it would help obviate the need for CSA and its associated nephrotoxicity. Clearly, MMF has emerged as an important new therapeutic option for the treatment of childhood nephrotic syndrome and FSGS. Further data are required to assess those conditions most likely to respond.

The pediatric nephrotic syndrome spectrum: clinical homogeneity and molecular heterogeneity

Idiopathic nephrotic syndrome is the most common glomerular disorder of childhood. Recurrence of nephrotic syndrome immediately following renal transplantation is rapid, results in a high rate of graft loss, and represents the most severe form of nephrotic syndrome. This review discusses the molecular heterogeneity of pediatric nephrotic syndrome across the spectrum of disease activity. A schema is offered for a molecular approach to pediatric nephrotic syndrome, including immune-mediated and structural/genetic factors.

The differential effect of race among pediatric kidney transplant recipients with focal segmental glomerulosclerosis

BACKGROUND

Given the differential effect of race on focal segmental glomerulosclerosis (FSGS) progression in native kidneys, recurrence of FSGS in the transplanted kidney, and allograft source, the authors conducted this study to evaluate the influence of FSGS by race and allograft source.

METHODS

Data from 8,065 pediatric renal transplant recipients (n = 620 FSGS) between 1987 and 1997 from the United Network for Organ Sharing registry were used for this study. Stratified analysis by race and allograft source allowed independent assessment of the effect of FSGS on transplant survival.

RESULTS

Among black children, allograft survival was not different between FSGS and non-FSGS patients adjusted for recipient age, recurrent disease, allograft source, zero antigen mismatch, and acute rejection (hazard ratio [HR], 1.15; 95% confidence interval [95% CI], 0.93 to 1.42; P = 0.22). Among nonblack children, the risk of allograft failure in children with FSGS was 1.31 times higher than other causes of end-stage renal disease (ESRD) in multivariate analysis (95% CI, 1.04 to 1.64; P = 0.02). Despite the impact of disease recurrence in the nonblack children with FSGS, the risk of graft failure was less for living donor recipients (HR, 1.51; 95% CI, 1.08 to 2.10) than for cadaveric recipients (HR, 1.80; 95% CI, 1.32 to 2.44) compared with the lowest risk group (nonblack, non-FSGS, living donor).

CONCLUSION

The effect of FSGS on renal allograft survival in children differs between racial groups. Children of nonblack races with FSGS have a worse allograft survival rate compared with other causes of ESRD. Within nonblack children with FSGS, living donor transplants convey a better allograft survival than cadaveric transplants.

The focal segmental glomerulosclerosis permeability factor: biochemical characteristics and biological effects

Focal segmental glomerulosclerosis (FSGS) is characterized by steroid resistant nephrotic syndrome and progression to end-stage renal disease. Proteinuria in certain patients with FSGS may be caused by a circulating factor (FSGS permeability factor [FSPF]). The current report documents the biochemical characteristics and the biological and molecular effects of 70% ammonium sulfate supernatant of plasma from patients with recurrence of FSGS after transplantation (FSGS 70% supernatant). FS permeability activity, defined as the capacity of plasma from patients with FSGS to increase albumin permeability (P(alb)) of isolated glomeruli, was assessed in vitro. Permeability activity was not affected by lyophilization. FSPF bound strongly to matrices containing Mono-Q anion exchanger or protein A. It eluted from matrix-bound Cibacron blue F3GA over a wide range of salt concentrations, indicating a potential binding with other proteins, such as albumin. FSPF caused a maximal increase in P(alb) within 2 mins of incubation in vitro. Cellular proteins isolated from glomeruli with increased P(alb) showed decreased tyrosine phosphorylation of focal adhesion kinase, paxillin, and other proteins. Tyrosine phosphatase ]inhibition prevented the increase in P(alb). Intravenous administration of as little as 3 mg protein in FSGS 70% supernatant increased P(alb), while 9 mg or more were required to produce proteinuria. We conclude that FSPF is a low-molecular-weight protein, carries an anionic charge, and binds to protein A. Effects of FSPF on the glomerular permeability barrier are rapid and dose dependent and involve signaling through altered phosphorylation of cellular proteins. Identification of these biochemical and biological characteristics may be used to design strategies for removing FSPF from circulation and for purification and identification of this factor.

Racial and ethnic differences in the incidence and progression of focal segmental glomerulosclerosis in children

Idiopathic focal segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome in pediatric and adult patients. Most children with FSGS do not respond to any form of therapy and progress to end-stage renal disease (ESRD). FSGS reoccurs in the transplanted kidney in approximately one third of initial transplants and in a substantially higher percentage of subsequent transplants once FSGS has recurred in an earlier transplant. Thus, FSGS is a disease with substantial morbidity. Over the past several years, the incidence of FSGS in adults and children appears to be increasing, particularly in certain racial groups and ethnic populations. Several recent studies in adult and pediatric patients suggest that the incidence of FSGS is increasing particularly in the black population. In addition, some studies have also demonstrated a more rapid progression of FSGS to ESRD in black patients compared to other ethnic groups. Racial and ethnic background is likely to have a substantial influence on the incidence and progression of FSGS in children and adults. It is likely that specific genes or a combination of genes influence the different clinical manifestations of FSGS in racial and ethnic groups. Genetic mutations in NPHS1 gene, which encodes nephrin, have been found to cause congenital nephrotic syndrome. Genetic mutations in the NPHS2 gene, which encodes podocin, recently have been shown to be strongly associated with a recessive form of steroid-resistant nephrotic syndrome. Mutations in the ACTN4 gene that encodes actinin 4 has also been associated with familial nephrotic syndrome. A role for ACE polymorphisms in the progression of FSGS has been found in some studies. Future investigations to identify polymorphisms that influence the development of FSGS, the progression of FSGS, and the response to therapy will greatly improve understanding of the pathogenesis and management of FSGS.

Intravenous pulse cyclophosphamide--is it effective in children with steroid-resistant nephrotic syndrome?

Treatment of steroid-resistant nephrotic syndrome (SRNS) remains a challenge to pediatric nephrologists. Recently, intravenous cyclophosphamide (IV-CPM) infusion was shown to be effective, safe, and economical for the treatment of SRNS, particularly minimal change disease (MCD), as it results in more sustained remissions, longer periods without proteinuria, and fewer significant side effects at a lower cumulative dose. A prospective study was conducted to evaluate IV-CPM infusions in the management of children with SRNS secondary to MCD or IgM nephropathy. Five patients with SRNS (4 IgM nephropathy and 1 MCD) received six monthly IV-CPM infusions at a dose of 500 mg/m(2). No patient achieved complete or sustained remission. Three patients attained partial remission, which was not sustained for more than 1 month post therapy. One patient progressed rapidly to end-stage renal disease during treatment. Side effects included vomiting in four patients and alopecia in one patient.

CONCLUSION

IV-CPM pulse therapy at a dose of 500 mg/m(2) is unsuccessful in obtaining complete or sustained remission in children with SRNS secondary to IGM nephropathy or MCD. Further randomized controlled studies with higher doses are required.

Single-center analysis of early recurrence of nephrotic syndrome following renal transplantation in children

Recurrence of nephrotic syndrome (NS) after transplantation (Tx) occurs in 20-50% of renal transplant recipients, with a median time to recurrence of 14 days and a 50% rate of graft loss. We performed a retrospective analysis of 22 pediatric patients with NS who received renal transplants at the Children's Hospital, Boston, between 1982 and 1999. During the first 14 days following Tx, 13 (59%) patients developed clinical recurrent nephrotic syndrome (RNS). RNS developed in 50% of living donor recipients and in 70% of cadaveric donor recipients (p= non-significant). Seven of the 13 patients with RNS were treated with plasmapheresis, while six received standard immunosuppressive induction therapy only. Two of the seven treated patients and one of the six untreated patients lost their grafts to RNS, yielding a total RNS graft loss rate of 23%. However, patients with RNS who achieved remission had significantly higher cumulative graft survival at 5 yr than did RNS patients who did not achieve remission (p< 0.001). Overall cumulative graft survival at 5 yr was not significantly different between the two groups: 67% in those with non-recurrent nephrotic syndrome (NRNS) vs. 64% in those with RNS, p= non-significant. We conclude that successful reversal of early RNS improves long-term graft survival in pediatric RNS. Multi-center studies are sorely needed to develop novel, less toxic therapies for native and recurrent NS.

Recurrent focal segmental glomerulosclerosis following renal transplantation in Korean pediatric patients

The recurrence of focal segmental glomerulosclerosis (FSGS) in transplants is a well-known problem in pediatric renal transplantation (Tx). Recently, the race of the recipient was recognized as a major variable associated with disease recurrence. In view of this finding, we report on our single-center experience of FSGS recurrence in Korean children, an ethnically homogeneous Far East Asian population. Clinical records and renal biopsy specimens, both native and graft, were reviewed for all pediatric renal Txs (recipient age < or = 18 yr) performed at Seoul National University Hospital from 1984 to 1999. Twenty-two children with primary FSGS received 22 allografts for renal replacement. The mean age of disease onset in these patients was 5.9 yr. The grafts were from 12 living-related, six living-unrelated, and four cadaveric donors, and all recipients were immunosuppressed with cyclosporin A (CsA)-based regimens. Post-transplant recurrence of FSGS was confirmed in nine patients (41%). Long-term graft survival in recurrent and non-recurrent groups was not significantly different. Risk factor analysis showed that patients with a disease duration shorter than 48 months (odds ratio 11.7, 95% CI 1.53-89.1) and a glomerulosclerosis percentage of < 55% by renal biopsy (odds ratio 16.0, 95% CI 1.45-176) were at greater risk of disease recurrence. These results suggest that Korean children are similar to non-African-American youngsters in the USA and Europe with respect to post-transplant recurrence of FSGS. The same may be true of other Far Eastern Asian children.

Increased nuclear factor-kappaB and angiotensinogen gene expression in posttransplant recurrent focal segmental glomerulosclerosis

In an attempt to identify potential markers of steroid-resistance in focal segmental glomerulosclerosis (FSGS) we evaluated intra-graft gene expression of IkappaBalpha, nuclear factor-kappaB (NF-kappaB), and angiotensinogen in 60 biopsies from 27 pediatric renal transplant recipients. Intra-graft NF-kappaB expression was significantly elevated in recurrent FSGS (R-FSGS) (218.3 + 55.6 ag/fg versus NON-FSGS 121.1 + 19.9, P=0.04) but not in acute rejection. NF-kappaB:IkappaBalpha ratios were higher in cadaveric donor versus living related donor recipients (15.7 + 2.8 vs. 8.8 + 1.3, respectively, P=0.015), and in African-American versus Caucasian recipients (15.6 + 2.9 vs. 9.1 + 1.3, respectively, P=0.03). Intra-graft angiotensinogen gene expression was significantly elevated in R-FSGS (30.5 + 8.8 ag/fg R-FSGS vs. 16.0 + 4.7 NON-FSGS, P=0.009). We conclude that increased NF-kappaB and angiotensinogen gene expression are associated with R-FSGS. Increased NF-kappaB:IkappaBalpha ratios are associated with cadaveric donor recipients and African-American race.

Pathology of progressive nephropathies

The role of cell cycle regulatory proteins in progression is elucidated. Human renal biopsy data show amelioration and even regression of structural injury with interventions. Data implicate new mechanisms of the renin-aldosterone-angiotensin system in progressive injuries, including immune modulation and a direct effect of aldosterone on progression. New approaches and interventions that target these fibrotic responses show promising results.