Ferroptosis-related genes, a novel therapeutic target for focal segmental glomerulosclerosis

Recent studies have suggested that ferroptosis participates in various renal diseases. However, its effect on focal segmental glomerulosclerosis remains unclear. This study analyzed the GSE125779 and GSE121211 datasets to identify the differentially expressed genes (DEGs) in renal tubular samples with and without FSGS. The Cytoscape was used to construct the protein-protein interaction network. Moreover, the ferroptosis-related genes (FRGs) were obtained from the ferroptosis database, while ferroptosis-related DEGs were obtained by intersection with DEGs. The target genes were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The GSE108112 dataset was used to verify the expression of target FRGs. Besides, we built the mRNA-miRNA network regarding FRGs using the NetworkAnalyst database, and circRNAs corresponding to key miRNAs were predicted in the ENCORI database. In this study, 16 ferroptosis-related DEGs were identified between FSGS and healthy subjects, while five co-expressed genes were obtained by three topological algorithms in Cytoscape. These included the most concerned Hub genes JUN, HIF1A, ALB, DUSP1 and ATF3. The KEGG enrichment analysis indicated that FRGs were associated with mitophagy, renal cell carcinoma, and metabolic pathways. Simultaneously, the co-expressed hub genes were analyzed to construct the mRNA-miRNA interaction network and important miRNAs such as hsa-mir-155-5p, hsa-mir-1-3p, and hsa-mir-124-3p were obtained. Finally, 75 drugs targeting 54 important circRNAs and FRGs were predicted. This study identified the Hub FRGs and transcriptomic molecules from FSGS in renal tubules, thus providing novel diagnostic and therapeutic targets for FSGS.

Perihilar FSGS lesions originate from flat parietal epithelial cells

Graphical Abstract

A Low-Protein, Plant-Dominant Gluten-Free Diet for Immunoglobulin A Nephropathy and Focal Segmental Glomerulosclerosis

Immunoglobulin A nephropathy is the most common glomerulonephritis syndrome in the world, yet there is currently no cure. While blood pressure control, renin-angiotensin-aldosterone system inhibition, and immunosuppression may slow disease progression, low-protein diets, defined as a daily dietary protein intake of 0.6 to 0.8 g/kg body weight, may also decrease immune complex deposition and disease severity, as evidenced in animal models. The link between secondary immunoglobulin A nephropathy and celiac disease has also led to the rise of gluten-free diets and zinc supplementation as potential lifestyle modifications to help manage common immunoglobulin A nephropathy symptoms such as proteinuria and hematuria. In addition, case reports and prospective studies suggest that patients with focal segmental glomerulosclerosis, which manifests as steroid-resistant nephrotic syndrome may also benefit from a gluten-free diet. We highlight the example of a gluten-free, plant-dominant low-protein diet (a different type of low-protein diet that addresses both protein quantity and quality) for patients with immunoglobulin A nephropathy or focal segmental glomerulosclerosis.

Focal Segmental Glomerulosclerosis Complicating Therapy With Inotersen, an Antisense Oligonucleotide Inhibitor: A Case Report

Inotersen is an antisense oligonucleotide inhibitor licensed for the treatment of polyneuropathy complicating hereditary transthyretin amyloidosis (ATTRv). Nephrotoxicity has been reported with inotersen, including progression to kidney failure. We describe what is to our knowledge the first reported case of inotersen-associated nephrotic syndrome secondary to focal segmental glomerulosclerosis (FSGS) and review the literature concerning inotersen-induced nephrotoxicity. We report a woman in her early 30s with ATTRv associated with the V50M transthyretin (TTR) variant, who presented with nephrotic syndrome 7 months after commencement of inotersen. Renal histology demonstrated FSGS and scanty glomerular amyloid deposition. Discontinuation of inotersen alone resulted in complete clinical and biochemical resolution of nephrotic syndrome. Inotersen is associated with significant nephrotoxicity. In the phase 3 NEURO-TTR clinical trial, 3% of patients in the treatment arm developed a crescentic glomerulonephritis. All affected patients carried the V50M TTR variant, which is known to be associated with renal amyloid deposition. This case adds to the spectrum of kidney disease associated with inotersen and indicates that discontinuation of the drug alone may result in resolution of renal complications without additional immunosuppression. Monitoring of kidney function is essential in patients with ATTRv receiving inotersen, particularly if there is evidence of existing renal amyloid.

Pathological evaluation of renal complications in children following allogeneic hematopoietic stem cell transplantation: a retrospective cohort study

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative therapy for hematologic malignancies and non-malignant disorders, such as aplastic anemia, fanconi anemia, and certain immune deficiencies. Post-transplantation kidney injury is a common complication and involves a wide spectrum of structural abnormalities, including glomerular (MSPGN, mesangial proliferative glomerulonephritis; FSGS, focal segmental glomerulosclerosis; MPGN, membranoproliferative glomerulonephritis; MCD, minimal change disease), vascular (TMA, thrombotic microangiopathy), and/or tubulointerstitial (TIN, tubulointerstitial nephritis; ATI, acute tubular injury). Renal biopsy is the gold-standard examination for defining multiple etiologies of kidney impairment. Although kidney injury following HSCT has been studied, little is known about the effects of allo-HSCT on renal pathology in pediatric patients.

METHODS

We retrospectively analyzed renal biopsy specimens from children with kidney injury after allo-HSCT and correlated results with clinical data in the last 10 years.

RESULTS

Among 25 children (18 males and 7 females), three patients had proteinuria indicating nephrotic syndrome (24-hour urinary total protein/weight > 50 mg/kg/d), nine patients had severely reduced estimated glomerular filtration rate (eGFR < 30 ml/min/1.73 m2) and four patients received kidney replacement therapy (KRT). The main pathologies identified from kidney biopsies were MSPGN (n = 12), FSGS (n = 12), MPGN (n = 5), TMA (n = 4), MCD (n = 3), diffuse glomerular fibrosis (DGF, n = 2), ATI and TIN, in isolation or combined with other pathologies. The median follow-up time was 16.5 (0.5 ~ 68.0) months. Three patients died of recurrent malignancy and/or severe infection, one child developed to end-stage renal disease (ESRD), six patients (24%) had elevated serum creatinine (SCr > 100µmol/l) and nine patients (36%) still had proteinuria.

CONCLUSIONS

This study evaluates histomorphologic findings from kidney biopsies of pediatric recipients following allo-HSCT. Detailed evaluation of renal biopsy samples is helpful to elucidate the nature of renal insult, and may potentially identify treatable disease processes.

Focal segmental glomerulosclerosis and proteinuria associated with Myo1E mutations: novel variants and histological phenotype analysis

BACKGROUND

Pathogenic mutations in the non-muscle single-headed myosin, myosin 1E (Myo1e), are a rare cause of pediatric focal segmental glomerulosclerosis (FSGS). These mutations are biallelic, to date only reported as homozygous variants in consanguineous families. Myo1e regulates the actin cytoskeleton dynamics and cell adhesion, which are especially important for podocyte functions.

METHODS

DNA and RNA sequencing were used to identify novel MYO1E variants associated with FSGS. We studied the effects of these variants on the localization of Myo1e in kidney sections. We then analyzed the clinical and histological observations of all known pathogenic MYO1E variants.

RESULTS

We identified a patient compound heterozygote for two novel variants in MYO1E and a patient homozygous for a deletion of exon 19. Computer modeling predicted these variants to be disruptive. In both patients, Myo1e was mislocalized. As a rule, pathogenic MYO1E variants map to the Myo1e motor and neck domain and are most often associated with steroid-resistant nephrotic syndrome in children 1-11 years of age, leading to kidney failure in 4-10 years in a subset of patients. The ultrastructural features are the podocyte damage and striking diffuse and global Alport-like glomerular basement membrane (GBM) abnormalities.

CONCLUSIONS

We hypothesize that MYO1E mutations lead to disruption of the function of podocyte contractile actin cables resulting in abnormalities of the podocytes and the GBM and dysfunction of the glomerular filtration barrier. The characteristic clinicopathological data can help to tentatively differentiate this condition from other genetic podocytopathies and Alport syndrome until genetic testing is done. A higher resolution version of the Graphical abstract is available as Supplementary information.

Liposorber® LA-15 system for LDL apheresis in resistant nephrotic syndrome patients

BACKGROUND

Steroid-resistant nephrotic syndrome (SRNS) is a major cause of stage 5 chronic kidney disease (CKD 5) in children. LDL apheresis (LDL-A) is now FDA approved for the treatment of pediatric focal segmental glomerulosclerosis (FSGS). Effective management of hyperlipidemia with LDL-A in SRNS patients may prevent progression of kidney disease and lead to remission. We report a case series of patients who received LDL-A for treatment of SRNS METHODS: We describe five children with SRNS who were treated with 12 sessions of LDL-A. Partial remission (PR) is defined as urine protein to creatinine ratio (UPC) of 0.2-2 (g/g) or decrease in UPC ≥ 50%, and complete remission (CR) is defined as UPC < 0.2 (g/g).

RESULTS

One patient achieved CR and three achieved PR. One patient did not respond to therapy. The earliest that a patient achieved PR was at treatment #10 and some did not respond until after LDL-A was completed. Those who responded stayed in either CR or PR for extended periods of time. LDL-A was successful at significantly reducing LDL (p < 0.001), total cholesterol (p < 0.001), and triglyceride (p < 0.001).

CONCLUSIONS

LDL-A was able to significantly decrease the lipid levels in these patients and induce CR and PR in the majority. The current study confirms previous studies showing those with a higher glomerular sclerosis burden were less likely to respond. LDL-A should be considered in patients with treatment-resistant SRNS and should be considered before there is a high burden of glomerular sclerosis to provide the best chance of success.

Pediatric focal segmental glomerulosclerosis: favorable transplantation outcome with plasma exchange

Background

Although kidney transplantation (KTX) is the treatment of choice for pediatric end stage kidney disease (ESKD); concerns for recurrence in cases of focal segmental glomerulosclerosis (FSGS) are still present. This study aimed to investigate the outcome of KTX in children with ESKD secondary to FSGS, with implementation of preemptive perioperative plasma exchange (PE) for non-genetically proven patients.

Methods

Forty FSGS pediatric kidney transplant recipients were studied. Of them: 12 patients (30%) had genetically proven NPHS2 mutations/familial and 28 (70%) were sporadic FSGS patients. All sporadic patients electively received 6 perioperative PE sessions. Patients with recurrence of proteinuria (n = 13; including 3 patients with genetic/familial and 10 patients with sporadic FSGS) were managed with PE and Rituximab (RTX). Kaplan-Meier curves were used to analyze graft and recurrence free survival data.

Results

The mean follow-up duration after KTX was 3.8 ± 2.86 years. Recurrence of proteinuria was encountered early postoperative in 11 patients (27.5%) and late (1.6 and 2.9 years after KTX) in 2 patients (5%). All patients with early recurrence achieved complete remission, while patients with late recurrence developed graft failure. Current serum creatinine and proteinuria levels were not different in patients received PE (n = 31) and patients did not PE (n = 9) (p = 0.308 and 0.287 respectively). Current serum creatinine and proteinuria levels in sporadic patients (n = 28) after prophylactic perioperative PE were not different from those of genetic/ familial patients (n = 12) (p = 0.303 and 0.144 respectively). Proteinuria was less in patients underwent native nephrectomy than others immediately postoperative and at assessment (p = 0.002 & 0.0031 respectively). One-year graft and patient survival was 93.8% with a mean 1-year serum creatinine of 0.67 ± 0.25 mg/dl. Three graft losses (7.5%) were due to chronic rejection 3.3, 3.75 and 4.17 years after KTX and 2 patients’ mortality (5%) occurred early postoperative (first 2 weeks).

Conclusion

FSGS transplanted children have favorable outcomes with perioperative PE for non-genetically proven cases. Early recurrence after KTX can be successfully managed with PE and RTX.

Health-Related Quality of Life in Focal Segmental Glomerular Sclerosis and Minimal Change Disease: A Qualitative Study of Children and Adults to Inform Patient-Reported Outcomes

RATIONALE & OBJECTIVE

Assessment of how patients feel and function is needed for clinical care and research for focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD). The objective of this study was to develop a patient-reported outcome assessment appropriate for use in children and adults with FSGS and MCD.

STUDY DESIGN

Qualitative study using semi-structured interviews.

SETTING & PARTICIPANTS

48 semi-structured interviews with children aged 8 to 17 years (n = 11) and adults (n = 10) with FSGS and children aged 8 to 17 (n = 11) and adults (n = 16) with MCD recruited from 3 academic medical centers.

ANALYTICAL APPROACH

Latent content analysis.

RESULTS

FSGS and MCD have a pervasive and comparable impact on physical, social, and mental health-related quality of life regardless of age or diagnosis. Physical symptoms of swelling, fatigue, and pain were articulated by most participants. Disease management was also a frequent topic of discussion; participants described their experiences with medication and associated side effects, as well as lifestyle changes made to manage their disease (ie, dietary changes and frequent medical appointments). These discussions often identified a profound impact on physical abilities and life participation. In many instances, participants described the negative impact these symptoms had on their mood and sense of self, with most participants reporting feelings of anxiety.

LIMITATIONS

Participants were primarily non-Hispanic White and English speaking, which may limit generalizability.

CONCLUSIONS

Our results suggest that there are commonalities to the FSGS-MCD patient experience of health-related quality of life that will enable the generation of a disease-specific FSGS-MCD patient-reported outcomes instrument for use in children and adults. The development of this tool is intended to facilitate better care and support clinical research for these individuals.

A girl with MIRAGE syndrome who developed steroid-resistant nephrotic syndrome: a case report

BACKGROUND

MIRAGE syndrome is a recently discovered rare genetic disease characterized by myelodysplasia (M), infection (I), growth restriction (R), adrenal hypoplasia (A), genital phenotypes (G), and enteropathy (E), caused by a gain-of-function mutation in the SAMD9 gene. We encountered a girl with molecularly-confirmed MIRAGE syndrome who developed steroid-resistant nephrotic syndrome.

CASE PRESENTATION

She was born at 33 weeks gestational age with a birth weight of 1064 g. She showed growth failure, mild developmental delays, intractable enteropathy and recurrent pneumonia. She was diagnosed as MIRAGE syndrome by whole exome sequencing and a novel SAMD9 variant (c.4615 T > A, p.Leu1539Ile) was identified at age four. Biopsied skin fibroblast cells showed changes in the endosome system that are characteristic of MIRAGE syndrome, supporting the genetic diagnosis. Proteinuria was noted at age one, following nephrotic syndrome at age five. A renal biopsy showed focal segmental glomerulosclerosis (FSGS) with immune deposits. Steroid treatment was ineffective. Because we speculated that her nephrosis was a result of genetic FSGS, we decided not to introduce immunosuppressive agents and instead started enalapril to reduce proteinuria. Although her proteinuria persisted, her renal function was normal at age eight.

CONCLUSIONS

This is the first detailed report of a MIRAGE syndrome patient with nephrotic syndrome. Because patients with MIRAGE syndrome have structural abnormalities in the endosomal system, we speculate that dysfunction of endocytosis in podocytes might be a possible mechanism for proteinuria.

Proteinuria Reduction and Kidney Survival in Focal Segmental Glomerulosclerosis

RATIONALE & OBJECTIVE

Remission of proteinuria has been shown to be associated with lower rates of kidney disease progression among people with focal segmental glomerulosclerosis (FSGS). The goal of this study was to evaluate whether reductions in proteinuria after treatment are associated with greater kidney survival.

STUDY DESIGN

Cohort analysis of clinical trial participants.

SETTING & PARTICIPANTS

Patients with steroid-resistant FSGS enrolled in a randomized treatment trial that compared cyclosporine with mycophenolate mofetil plus dexamethasone.

PREDICTORS

Reduction in proteinuria measured during 26 weeks after initiating treatment.

OUTCOMES

Repeated assessments of estimated glomerular filtration rate (eGFR) and time to a composite outcome of kidney failure or death assessed between 26 weeks and 54 months after randomization.

ANALYTICAL APPROACH

Multivariable linear mixed-effects models with participant-specific slope and intercept to estimate the association of change in proteinuria over 26 weeks while receiving treatment with the subsequent slope of change in eGFR. Multivariable time-varying Cox proportional hazards models were used to estimate the association of changes in proteinuria with time to the composite outcome.

RESULTS

138 of 192 trial participants were included. Changes in proteinuria over 26 weeks were significantly related to eGFR slope. A 1-unit reduction in log-transformed urinary protein-creatinine ratio was associated with a 3.90mL/min/1.73m² per year increase in eGFR (95% CI, 2.01-5.79). This difference remained significant after adjusting for complete remission. There was an analogous relationship between time-varying proteinuria and time to the composite outcome: the HR per 1-unit reduction in log-transformed urinary protein-creatinine ratio was 0.23 (95% CI, 0.12-0.44).

LIMITATIONS

Limited to individuals with steroid-resistant FSGS followed up for a maximum of 5 years.

CONCLUSIONS

These findings provide evidence for the benefit of urinary protein reduction in FSGS. Reductions in proteinuria warrant further evaluation as a potential surrogate for preservation of kidney function that may inform the design of future clinical trials.

Rituximab therapy for refractory steroid-resistant nephrotic syndrome in children

Patients with steroid-resistant nephrotic syndrome (SRNS) who develop resistance to immunosuppressive agents, defined as refractory SRNS, have poor renal outcomes. Although the chimeric anti-CD20 monoclonal antibody rituximab has shown efficacy for frequently relapsing nephrotic syndrome and steroid-dependent nephrotic syndrome, its efficacy for refractory SRNS remains uncertain due to limited data. According to previous case reports, 50.4% of patients with refractory SRNS showed clinical improvements after rituximab treatment. Remission rates in patients with initial steroid resistance and late steroid resistance were 43.9 and 57.7%, respectively, and 41.5 and 63.6% in patients with focal segmental glomerulosclerosis and minor glomerular abnormalities, respectively. However, various factors (race, disease severity, number of rituximab doses, concomitant treatments, and observation period) differed among these observational studies and their consensus may also have been affected by potential publication bias. Rituximab monotherapy may have some degree of efficacy and lead to satisfactory outcomes in a subset of patients with refractory SRNS. However, administration of concomitant treatments during rituximab-mediated B cell depletion, such as methylprednisolone pulse therapy, daily oral prednisolone therapy, and immunosuppressive agents, may lead to better outcomes in these patients. Large-scale, multi-center prospective studies are needed to evaluate the efficacy and safety of such regimens.

LDL-apheresis-induced remission of focal segmental glomerulosclerosis recurrence in pediatric renal transplant recipients

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) in pediatric patients is typically difficult to treat and will progress to end-stage renal disease (ESRD) in about 10% of cases. Following kidney transplantation, FSGS can recur in up to 56% of renal allografts-with a near 100% recurrence in subsequent transplants.

METHODS

Four different pediatric centers across the USA and the UK employed a protocol using LDL-apheresis (LDL-A) and pulse solumedrol to treat recurrent FSGS after transplantation in seven patients. All the patients included in this series demonstrated immediate, or early, recurrence of FSGS, which clinically presented as nephrotic-range proteinuria within hours to days after implantation of the kidney.

RESULTS

All patients experienced reductions in urinary protein to creatinine ratios resulting in partial or complete remission. All patients demonstrated improvements in their estimated GFRs at their most recent follow-up since LDL-A discontinuation.

CONCLUSIONS

This case series describes the successful treatment, across four different pediatric centers, of seven pediatric patients with recurrent post-transplant FSGS using the Liposorber® LA-15 in combination with pulse solumedrol.

Transplantation of umbilical cord mesenchymal stem cells into mice with focal segmental glomerulosclerosis delayed disease manifestation

Background

Familial focal segmental glomerulosclerosis (fFSGS) is difficult to treat, and stem cell transplantation is one of the most promising approaches for treating this condition. According to the novel mutation site found in our FSGS family, we established a novel animal model of FSGS to explore the application of stem cell therapy in FSGS.

Methods

The animal model used in this experiment was p.Gly1617Valfs X15 (C57BL/6) mutant mice. This mutation was first found in a focal segmental glomerulosclerosis (FSGS) family undergoing renal biopsy in our department. The mouse model was then constructed via CRISPR/Cas9 genomic editing technology. Then, the animals were injected with human umbilical cord mesenchymal stem cells (UCMSC) through the tail vein and regularly followed up to determine phenotypic changes in urine protein quantities, serum creatinine and histological outcomes.

Results

Compared with the positive control group, the levels of urinary protein and serum creatine were decreased significantly after UCMSC transplantation. HE staining images revealed a delay in glomerular sclerosis. Moreover, the secretion of the type IV collagen α3 chain was significantly increased compared with the positive control group, as shown by using immunofluorescence microscopic observation, and electron microscopy proved that the podocytes and basement membrane recovered well from the damage. The intervention also resulted in enhanced IL-22 expression.

Conclusions

UCMSC transplantation may be a potential treatment for FSGS, and IL-22 may play an important role in this process. Further studies are needed to reveal the underlying mechanism.

Collapsing Lesions and Focal Segmental Glomerulosclerosis in Pregnancy: A Report of 3 Cases

The relationship between focal segmental glomerulosclerosis (FSGS) and pregnancy is complex and not completely elucidated. Pregnancy in patients with FSGS poses a high risk for complications, possibly due to hemodynamic factors, imbalance between angiogenic and antiangiogenic factors, and hormonal conditioning. Although poor clinical outcomes associated with collapsing FSGS are common outside of pregnancy, the prognosis during pregnancy is not well documented. We report 3 patients who developed collapsing FSGS during pregnancy, 2 of whom had presumed underlying FSGS. Two patients underwent biopsy during pregnancy, and 1, during the puerperium. None of the 3 patients improved spontaneously after delivery, and 1 experienced a rapid deterioration in kidney function and proteinuria after delivery. Aggressive immunosuppressive therapy led to a full response in 1 case (without chronic lesions) and to partial responses in the remaining 2 cases. These cases suggest that collapsing lesions should be considered in patients with FSGS who develop a rapid increase in serum creatinine level or proteinuria during pregnancy and that these lesions may at least partially respond to treatment.

Mortality and Allograft Loss Trends Among US Pediatric Kidney Transplant Recipients With and Without Focal Segmental Glomerulosclerosis

BACKGROUND

Pediatric patients with focal segmental glomerulosclerosis (FSGS) have high rates of disease recurrence and allograft failure after kidney transplantation, but there are few data for long-term survival posttransplantation.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

12,303 pediatric patients (aged <18 years), including 1,408 (11%) patients with FSGS, who received a first kidney transplant in 1990 through 2009 and were followed up through June 2015 were identified from the US Renal Data System database.

PREDICTORS

Primary cause of end-stage renal disease, FSGS or other.

OUTCOMES

All-cause patient mortality and allograft loss.

RESULTS

All-cause mortality significantly improved for patients with FSGS who underwent transplantation in the 2000s versus the 1990s (6.72 vs 12.24 deaths/1,000 patient-years; HR, 0.55; 95% CI, 0.39-0.78; P<0.001). Reductions in allograft loss were less dramatic (75.91 vs 89.05 events/1,000 patient-years; HR, 0.85; 95% CI, 0.74-0.98; P=0.02). After adjusting for baseline characteristics at the time of transplantation, patients with FSGS had similar rates of death compared with patients without FSGS (HRs of 0.81 [P=0.6] and 1.06 [P=0.2] among those who underwent transplantation in the 2000s and 1990s, respectively) despite higher rates of allograft loss (HRs of 1.17 [P=0.03] and 1.27 [P<0.001], respectively). Among patients who underwent transplantation in the 2000s, further adjustment for allograft failure as a time-varying covariate demonstrated a lower rate of death among patients with FSGS compared with those without FSGS (HR, 0.70; P=0.02).

LIMITATIONS

Lack of information about certain risk factors for mortality, including duration of chronic kidney disease; missing data; and potential primary disease misclassification.

CONCLUSIONS

Survival of pediatric kidney transplant recipients with FSGS improved between the 1990s and 2000s and was similar to that of recipients without FSGS. Interestingly, adjustment for allograft failure showed greater survival for pediatric patients with FSGS who underwent transplantation in the 2000s as compared with others, suggesting that effective interventions to decrease allograft loss due to disease recurrence may improve patient survival.

Focal segmental glomerulosclerosis; why does it occur segmentally?

Podocyte loss is the fundamental basis of glomerulosclerosis. Focal segmental glomerulosclerosis (FSGS) is a progressive glomerular disease, and its glomerular features are a prototype of podocyte loss-driven glomerulosclerosis. The glomerular pathology of FSGS is characterized by a focal and segmental location of the sclerotic lesions in human FSGS; segmental sclerosis often shows simultaneous intra- and extra-capillary changes, including parietal cell migration, capillary collapse, hyaline deposition, and intra-capillary thrombi and occasional hypercellularity. This suggests that local cellular events, initiated by podocyte loss, are the basis of the segmental lesions in FSGS. Using podocyte-specific injury by toxin administration, a series of recent works has identified the cellular basis of the glomerular response to podocyte loss. This review discusses the molecular pathway of the local response to podocyte loss and its progression to sclerosis. Recent results suggest that segmental sclerosis is a physiological tissue response aimed at halting protein leakage from a disrupted filtration barrier.

Histological patterns of idiopathic steroid resistant nephrotic syndrome in Egyptian children: A single centre study

BACKGROUND

BACKGROUND

Idiopathic steroid resistant nephrotic syndrome (ISRNS) represents about 10-20% of children with nephrotic syndrome with variable outcome.

OBJECTIVES

To determine the histological patterns of ISRNS in Egyptian children and the histological details of the commonest types which might be the reason for the steroid resistance.

PATIENTS AND METHODS

The study included 53 cases with ISRNS. Their renal biopsies were retrieved from the archive of Electron microscopy unit and pathology department, Ain Shams University Specialized Hospital (ASUSH) in the duration from 2005-2011. The biopsies were examined histologically, with immunohistochemistry, and by electron microscopy.

RESULTS

They were 36 males (67.9%) and 17 females (32.1%), the age at diagnosis ranged from 1.5- 16 years with a mean of 6.71 years. Lower limb oedema was the commonest presentation (100%), haematuria was revealed in (17%) of cases. Histological examination showed three major patterns; Focal segmental glomerulosclerosis (FSGS) in 30.2%, minimal change glomerulopathy (MCG) in 24.5% and IgA nephropathy in 13.2 %. Mesangial hypercellularity was very common among MCG patients (85.3% ±6.7). Tubulointerstitial inflammation and fibrosis were common among cases with IgA nephropathy (40.4% ±11, 53.7% ±8 respectively).

CONCLUSIONS

ISRNS in Egyptian children could be attributed mainly to three major diseases (FSGS, MCG and IgA nephropathy). Mesangial hypercellularity and severe tubulointerstitial disease might be the major causes for steroid resistance in MCG and IgA nephropathy respectively. Renal biopsy with electron microscopy examination should be done for all children with nephrotic syndrome at first time of presentation for proper assignment of treatment protocol.