Focal And Segmental Glomerulosclerosis Research Articles

Inhibition of RAC attenuates Adriamycin-induced podocyte injury

Minimal Change Disease (MCD), which is associated with podocyte injury, is the leading cause of nephrotic syndrome in children. A considerable number of patients experience relapses and require prolonged use of prednisone and immunosuppressants. Multi-drug resistance and frequent relapses can lead to disease progression to focal and segmental glomerulosclerosis (FSGS).To identify potential targets for therapy of podocyte injury, we examined microarray data of mRNAs in glomerular samples from both MCD patients and healthy donors, obtained from the GEO database. Differentially expressed genes (DEGs) were used to construct the protein-protein interactions (PPI) network through the application of the search tool for the retrieval of interacting genes (STRING) tool. The most connected genes in the network were ranked using cytoHubba. 16 hub genes were selected and validated by qRT-PCR. RAC2 was identified as a potential therapeutic target for further investigation. By downregulating RAC2, Adriamycin (ADR)-induced human podocytes (HPCs) injury was attenuated. EHT-1864, a small molecule inhibitor that targets the RAC (RAC1, RAC2, RAC3) family, proved to be more effective than RAC2 silencing in reducing HPCs injury. In conclusion, our research suggests that EHT-1864 may be a promising new molecular drug candidate for patients with MCD and FSGS.

Protective Role of the Podocyte IL-15 / STAT5 Pathway in Focal Segmental Glomerulosclerosis

IntroductionDuring glomerular diseases, podocyte-specific pathways can modulate the intensity of histological disease and prognosis. The therapeutic targeting of these pathways could thus improve the management and prognosis of kidney diseases. The Janus Kinase/ Signal Transducer and Activator of Transcription (JAK/STAT) pathway, classically described in immune cells, has been recently detailed in intrinsic kidney cells. MethodsWe describe STAT5 expression in human kidney biopsies from patients with focal and segmental glomerulosclerosis (FSGS) and studied mice with a podocyte-specific Stat5 deletion in experimental glomerular diseases. ResultsHere, we show, for the first time, that STAT5 is activated in human podocytes in FSGS. Additionally, podocyte-specific Stat5 inactivation aggravates the structural and functional alterations in a mouse model of FSGS. This could be due, at least in part, to an inhibition of autophagic flux. Finally, Interleukin 15 (IL-15), a classical activator of STAT5 in immune cells, increases STAT5 phosphorylation in human podocytes and its administration alleviates glomerular injury in vivo by maintaining autophagic flux in podocytes. ConclusionIn conclusion, activating podocyte STAT5 with commercially available IL-15 represents a potential new therapeutic avenue for FSGS.

Podocyte number and glomerulosclerosis indices are associated with the response to therapy for primary focal segmental glomerulosclerosis.

Corticosteroid therapy, often in combination with inhibition of the renin-angiotensin system, is first-line therapy for primary focal and segmental glomerulosclerosis (FSGS) with nephrotic-range proteinuria. However, the response to treatment is variable, and therefore new approaches to indicate the response to therapy are required. Podocyte depletion is a hallmark of early FSGS, and here we investigated whether podocyte number, density and/or size in diagnostic biopsies and/or the degree of glomerulosclerosis could indicate the clinical response to first-line therapy. In this retrospective single center cohort study, 19 participants (13 responders, 6 non-responders) were included. Biopsies obtained at diagnosis were prepared for analysis of podocyte number, density and size using design-based stereology. Renal function and proteinuria were assessed 6 months after therapy commenced. Responders and non-responders had similar levels of proteinuria at the time of biopsy and similar kidney function. Patients who did not respond to treatment at 6 months had a significantly higher percentage of glomeruli with global sclerosis than responders (p < 0.05) and glomerulosclerotic index (p < 0.05). Podocyte number per glomerulus in responders was 279 (203-507; median, IQR), 50% greater than that of non-responders (186, 118-310; p < 0.05). These findings suggest that primary FSGS patients with higher podocyte number per glomerulus and less advanced glomerulosclerosis are more likely to respond to first-line therapy at 6 months. A podocyte number less than approximately 216 per glomerulus, a GSI greater than 1 and percentage global sclerosis greater than approximately 20% are associated with a lack of response to therapy. Larger, prospective studies are warranted to confirm whether these parameters may help inform therapeutic decision making at the time of diagnosis of primary FSGS.

Inhibition of the glucocorticoid receptor attenuates proteinuric kidney diseases in multiple species.

Glucocorticoids are the treatment of choice for proteinuric patients with minimal-change disease (MCD) and primary focal and segmental glomerulosclerosis (FSGS). Immunosuppressive as well as direct effects on podocytes are believed to mediate their actions. In this study, we analyzed the anti-proteinuric effects of inhibition of the glucocorticoid receptor (GR) in glomerular epithelial cells, including podocytes. We employed genetic and pharmacological approaches to inhibit the GR. Genetically, we used Pax8-Cre/GRfl/fl mice to specifically inactivate the GR in kidney epithelial cells. Pharmacologically, we utilized a glucocorticoid antagonist called mifepristone. Genetic inactivation of GR, specifically in kidney epithelial cells, using Pax8-Cre/GRfl/fl mice, ameliorated proteinuria following protein overload. We further tested the effects of pharmacological GR inhibition in three models and species: the puromycin-aminonucleoside-induced nephrosis model in rats, the protein overload model in mice and the inducible transgenic NTR/MTZ zebrafish larvae with specific and reversible podocyte injury. In all three models, both pharmacological GR activation and inhibition consistently and significantly ameliorated proteinuria. Additionally, we translated our findings to humans, where three nephrotic adult patients with MCD or primary FSGS with contraindications or insufficient responses to corticosteroids, were treated with mifepristone. This treatment resulted in a clinically relevant reduction of proteinuria. Thus, across multiple species and proteinuria models, both genetic and pharmacological GR inhibition was at least as effective as pronounced GR activation. While, the mechanism remains perplexing, GR inhibition may be a novel and targeted therapeutic approach to treat glomerular proteinuria potentially bypassing adverse actions of steroids.

Proteomics of Plasma and Plasma-Treated Podocytes: Application to Focal and Segmental Glomerulosclerosis.

Focal and segmental glomerulosclerosis (FSGS) is a severe form of idiopathic nephrotic syndrome (INS), a glomerulopathy of presumably immune origin that is attributed to extrarenal pathogenic circulating factors. The recurrence of FSGS (rFSGS) after transplant occurs in 30% to 50% of cases. The direct analysis of patient plasma proteome has scarcely been addressed to date, mainly due to the methodological difficulties associated with plasma complexity and dynamic range. In this study, first, we compared different methods of plasma preparation, second, we compared the plasma proteomes of rFSGS and controls using two preparation methods, and third, we analyzed the early proximal signaling events in podocytes subjected to patient plasma, through a combination of phosphoproteomics and lipid-raft proteomics (raftomics). By combining immunodepletion and high pH fractionation, we performed a differential proteomic analysis of soluble plasma proteins and of extracellular vesicles (EV) obtained from healthy controls, non-INS patient controls, and rFSGS patients (n = 4). In both the soluble- and the EV-protein sets from the rFSGS patients, we found a statistically significant increase in a cluster of proteins involved in neutrophil degranulation. A group of lipid-binding proteins, generally associated with lipoproteins, was found to be decreased in the soluble set from the rFSGS patients. In addition, three amino acid transporters involved in mTORC1 activation were found to be significantly increased in the EV from the rFSGS. Next, we incubated human podocytes for 30 min with 10% plasma from both groups of patients. The phosphoproteomics and raftomics of the podocytes revealed profound differences in the proteins involved in the mTOR pathway, in autophagy, and in cytoskeleton organization. We analyzed the correlation between the abundance of plasma and plasma-regulated podocyte proteins. The observed changes highlight some of the mechanisms involved in FSGS recurrence and could be used as specific early markers of circulating-factor activity in podocytes.

High Rate of Mutations of Adhesion Molecules and Extracellular Matrix Glycoproteins in Patients with Adult-Onset Focal and Segmental Glomerulosclerosis.

(1) Background: Focal and segmental glomerulosclerosis (FSGS) is a pattern of injury that results from podocyte loss in the setting of a wide variety of injurious mechanisms. These include both acquired and genetic as well as primary and secondary causes, or a combination thereof, without optimal therapy, and a high rate of patients develop end-stage renal disease (ESRD). Genetic studies have helped improve the global understanding of FSGS syndrome; thus, we hypothesize that patients with primary FSGS may have underlying alterations in adhesion molecules or extracellular matrix glycoproteins related to previously unreported mutations that may be studied through next-generation sequencing (NGS). (2) Methods: We developed an NGS panel with 29 genes related to adhesion and extracellular matrix glycoproteins. DNA was extracted from twenty-three FSGS patients diagnosed by renal biopsy; (3) Results: The average number of accumulated variants in FSGS patients was high. We describe the missense variant ITGB3c.1199G>A, which is considered pathogenic; in addition, we discovered the nonsense variant CDH1c.499G>T, which lacks a Reference SNP (rs) Report and is considered likely pathogenic. (4) Conclusions: To the best of our knowledge, this is the first account of a high rate of change in extracellular matrix glycoproteins and adhesion molecules in individuals with adult-onset FSGS. The combined effect of all these variations may result in a genotype that is vulnerable to the pathogenesis of glomerulopathy.

#6930 TOO ELDERLY FOR A KIDNEY BIOPSY?

Abstract Background and Aims As we age, we lose kidney function and accumulate risk factors and comorbidities that predispose to kidney damage. However, kidney disease can develop at any time. Life expectancy continues to improve worldwide. For that reason, more elderly patients are undergoing diagnostic kidney biopsies (KB). There is a general reluctance in performing KB in those patients. It is important to know if a diagnosis KB in elderly patients can have a positive therapeutic impact. Method In this retrospective cohort study, we analyzed the medical charts of all patients aged ≥ 80years who underwent a native kidney biopsy (KB) between January and December 2021, in a central hospital in Portugal. Results Between January and December 2021, 59 patients underwent a native KB, 6 of them over 80 years of age (10% of all patients). Between those elderly patients, the median age was 82 years. The indications for KB were chronic kidney disease with a nephrotic range proteinuria in 3 patients, nephrotic syndrome, acute glomerulonephritis and acute kidney injury in 1 patient each. Median serum creatinine was 2.27 mg/dL (minimum 0.8 and maximum 5.4 mg/dL) and median protein-to-creatinine ratio was 5.7g/g (minimum 3.3 and maximum 13g/g). The pathological diagnoses found were focal and segmental glomerulosclerosis (FSGS) (n=2), pauci-immune crescentic glomerulonephritis (n=1), membranous nephropathy in a patient with a follicular lymphoma (n=1), acute interstitial nephritis (AIN) (n=1), and diabetic glomerulosclerosis in a patient with a monoclonal gammopathy of undetermined significance (n=1). 3 patients have received a kidney-specific treatment – the patient with AIN started corticosteroids, one patient with FSGS was submitted to corticosteroids plus tacrolimus, and the patient with pauci-imune crescentic glomerulonephritis to corticosteroids plus rituximab. The patient with membranous nephropathy and follicular lymphoma received a specific chemotherapy regimen according with lymphoproliferative disease. An improvement in kidney function occurred only in one patient and the other three developed adverse effects (particularly corticosteroids induced diabetes and infections). One year later, one of patients who received treatment was dead, another one was on hemodialysis, and the other two patients had a glomerular filtration rate lower than 15mL/min/1.73 m2. Conclusion Elderly patients have a higher risk of adverse effects from the kidney-specific treatment. It is important to assess the therapeutic risk/benefit when considering performing a renal biopsy in these patients.

#6883 PROTECTIVE ROLE OF THE PODOCYTE IL-15 / STAT5 PATHWAY IN EXPERIMENTAL FOCAL AND SEGMENTAL GLOMERULOSCLEROSIS

Abstract Background and Aims During glomerular diseases, podocyte-specific pathways can modulate the intensity of histological disease and prognosis. The therapeutic targeting of these pathways could thus improve the management and prognosis of kidney diseases. The Janus Kinase/ Signal Transducer and Activator of Transcription (JAK/STAT) pathway, classically described in immune cells, has been recently detailed in intrinsic kidney cells. We previously evidenced a protective role for a podocyte-expressed immune receptor such as the common gamma chain (ΓC) during glomerulonephritis (1). We also found that STAT5, a transcriptional factor classically described and activated downstream ΓC in T cells is upregulated in podocytes during glomerulonephritis. Method Using a mice model with a podocyte-specific deletion of Stat5, we analyzed the role of STAT5 in two experimental models of glomerular diseases. Results Here, we show, for the first time, that STAT5 is activated in human podocytes in focal and segmental glomerulosclerosis (FSGS). Additionally, podocyte-specific Stat5 inactivation aggravates the structural and functional alterations in a mouse model of FSGS (Figure 1). This could be due, at least in part, to an inhibition of autophagic flux and an alteration of mitochondrial function. Finally, Interleukin 15 (IL-15), a classical activator of STAT5 in immune cells, increases STAT5 phosphorylation in human podocytes and its administration alleviates glomerular injury in vivo by maintaining autophagic flux in podocytes. Conclusion In conclusion, activating podocyte STAT5 with commercially available IL-15 represents a potential new therapeutic avenue for FSGS.

Egyptian pediatric clinical practice adapted guidelines: evidence-based [2] steroid-resistant nephrotic syndrome (SRNS) 2022

BackgroundNephrotic syndrome is one of the most common chronic kidney diseases in children. Steroid sensitive type (SSNS) constitutes about 85–90%, whereas steroid-resistant type (SRNS) only 15–20% (Mickinney et al. Pediatr Nephrol 16:1040-1044, 2001). While MCD is the most common histopathology in SS type, children with SRNS have MCD, mesangial proliferative glomerulonephritis, or focal and segmental glomerulosclerosis (FSGS) (International Study Kidney Disease in children, Kidney Int 20;765-771, 1981). SRNS is defined as those who do not show remission after 6 weeks and standard dose of oral steroids ± 3 IV MPD doses (Trautmann et al. Pediatr Nephrol 35:1529-1561, 2020).ObjectivesThese national adapted guidelines aim to frame evidence-based recommendations adopted or adapted from the IPNA 2020, KDIGO 2021, and Japanese 2014 de novo guidelines for diagnosis and management of nephrotic children to be presented in two manuscripts: (1) steroid sensitive (SSNS) and (2) steroid-resistant nephrotic syndrome (SRNS).MethodologyFormulation of key questions was followed with a review of literature guided by our appraised guidelines using AGREE plus appraisal tool. Virtual monthly meetings all through the year 2021 were activated for reviewing and validation of final adaptation evidence-based draft, considering all comments of external reviewers including KDIGO assigned reviewer.DiscussionRationale behind the selection of adopted statements and tailoring of others to suit our local facilities, expertise, and our local disease profile was discussed in the text with reasons.ConclusionThe provided guidelines aim to optimize patient care and outcome and suggest research areas lacking validated research recommendations.

A Study of Focal and Segmental Glomerulosclerosis according to the Columbia Classification and Its Correlation with the Clinical Outcome.

Introduction Focal and segmental glomerulosclerosis (FSGS) is a leading cause of nephrotic syndrome in both adults and children. The "Columbia classification of FSGS" includes five variants; not otherwise specified (NOS), tip, perihilar, cellular, and collapsing variants that may have different prognostic and therapeutic implications. Materials and Methods This is a retrospective study and was carried out in the Department of Histopathology, Apollo Hospitals, Hyderabad. Of a total of 11,691 kidney biopsies over a 7-year period, from 2006 to 2012, 824 cases were diagnosed as FSGS, of which 610 cases in which detailed clinical findings were available were included in this study. FSGS was then categorized according to the Columbia classification. Results FSGS, NOS was the predominant histomorphological variant. Serum creatinine was significantly high in the collapsing variant, followed by NOS. Follow-up data was available for 103 cases,72.8% had complete remission, 10.6% had partial remission, and in 16.5 % there was no remission. Relapses were observed in 6.7% cases, two patients (1.9%) succumbed, and 4.8% cases progressed to chronic kidney disease. Conclusion This study showed that perihilar variant was less prevalent, with tip and cellular variants being more prevalent in Indian subcontinent compared to Western literature. Collapsing variant was also less common.

Determination of Anti-Phospholipase A2 and Anti-Thrombospondin Type 1 Domain-Containing Protein 7A in Latin Patients with Membranous Nephropathy

Primary membranous nephropathy (MN) is caused by antibodies against podocyte antigens, especially the type M receptor of phospholipase A2 (PLA2R) and thrombospondin type-1 domain containing 7 A (THSD7A). This study's aim was the determination of anti-PLA2R, anti-THSD7A serum antibodies, and anti-PLA2R renal tissue staining prevalence in a Latin population with MN, as well as evaluating their role as biomarkers for disease activity. The performance of the two anti-PLA2R serum diagnostic methods-ELISA and indirect immunofluorescence (IFI)-was evaluated for the diagnosis of MN. Fifty-nine patients, including 29 with MN, 18 with lupus membranous nephropathy (LMN) and 12 with focal and segmental glomerulosclerosis (FSGS), were evaluated for serum antibodies. Renal biopsies were also evaluated for the presence of anti-PLA2R staining. Twenty-one patients with MN were followed for 1 year. Patients with LMN and FSGS were negative for both antibodies. All 29 MN patients were negative for anti-THSD7A; 16 MN patients were positive for anti-PLA2R by ELISA and/or IFI, and 3 MN patients were positive for anti-PLA2R only by IFI. Thus, the anti-PLA2R ELISA test demonstrated 45% sensitivity and 97% specificity, while the IFI test showed, respectively, 55% and 100% in our MN patients. Among the 28 MN renal biopsies, 20 presented anti-PLA2R positive staining, corresponding to a 72% sensitivity. Positive correlations were observed between the anti-PLA2R ELISA titer and proteinuria. In conclusion, determination of anti-PLA2R antibodies in the MN Latin population showed similar rates to those reported for other populations. The anti-PLA2R serum levels correlated with MN disease activity.

Mesangial Injury and Capillary Ballooning Precede Podocyte Damage in Nephrosclerosis

The development of focal and segmental glomerulosclerosis (FSGS) as a consequence of glomerular hypertension resulting from arterial hypertension is widely considered a podocyte disease. However, the primary damage is encountered in the mesangium. In acute settings, mesangial cells disconnect from their insertions to the glomerular basement membrane, causing a ballooning of capillaries and severe changes of the folding pattern of the glomerular basement membrane, of the arrangement of the capillaries, and thereby of the architecture of the tuft. The displacement of capillaries led to contact of podocytes and parietal epithelial cells, initiating the formation of tuft adhesions to Bowman's capsule, the committed lesion to progress to FSGS. In addition, the displacement of capillaries also caused an abnormal stretching of podocytes, resulting in podocyte damage. Thus, the podocyte damage that starts the sequence to FSGS is predicted to develop secondary to the mesangial damage. This sequence was found in two hypertensive rat models of FSGS and in human hypertensive nephrosclerosis.

TRPC6 Inactivation Reduces Albuminuria Induced by Protein Overload in Sprague Dawley Rats.

Canonical transient receptor potential-6 (TRPC6) channels have been implicated in familial and acquired forms of focal and segmental glomerulosclerosis (FSGS), and in renal fibrosis following ureteral obstruction in mice. TRPC6 channels also appear to play a role in driving glomerular disease in aging and in autoimmune glomerulonephritis. In the present study, we examine the role of TRPC6 in the proteinuric state caused by prolonged albumin overload (AO) in Sprague Dawley rats induced by daily injections of exogenous albumin. This was assessed in rats with a global and constitutive inactivation of TRPC6 channels (Trpc6del/del rats) and in wild-type littermates (Trpc6wt/wt rats). AO for 14 and 28 days caused increased urine albumin excretion that was significantly attenuated in Trpc6del/del rats compared to Trpc6wt/wt controls. AO overload did not induce significant glomerulosclerosis or azotemia in either genotype. AO induced mild tubulointerstitial disease characterized by fibrosis, hypercellularity and increased expression of markers of fibrosis and inflammation. Those changes were equally severe in Trpc6wt/wt and Trpc6del/del rats. Immunoblot analysis of renal cortex indicated that AO increased the abundances of TRPC3 and TRPC6, and caused a nearly complete loss of TRPC5 in Trpc6wt/wt rats. The increase in TRPC3 and the loss of TRPC5 occurred to the same extent in Trpc6del/del rats. These data also suggest that TRPC6 plays a role in the normal function of the glomerular filtration barrier. However, whether TRPC6 inactivation protects the tubulointerstitial compartments in Sprague Dawley rats depends on the disease model examined.

MO203: Minimal Change Disease Secondary to SARS-COV-2 (COVID-19) Infection: A Report of 2 Cases and Review of Related Literature

Abstract &amp;gt;BACKGROUND AND AIMS The COVID-19 pandemic has brought to the forefront a wide spectrum of renal injuries that included glomerulopathies, some of which were recently highlighted in various case reports. These consist of focal and segmental glomerulosclerosis (FSGS) and minimal change disease (MCD).1 These changes were found among seemingly vulnerable populations such as the African American and Caucasian ethnicities with paucity of reports among other races. We present two cases of biopsy-confirmed MCD secondary to COVID-19 infection among adult Filipino patients. METHODS Case Report RESULTS: Case 1 A 40-year-old Filipino female with a history of right total mastectomy 2 years prior for a low-grade phyllodes tumor and no other medical comorbidities was admitted due to stillbirth. She was noted to have bipedal edema with a positive COVID-19 RT-PCR swab. Further workup revealed a serum creatinine 1.04 mg/dL, urine RBC 1/HPF and a 24-h urine protein of 9.22 g with hypoalbuminemia and dyslipidemia. Serologic workup was noted to be negative. She was started on Losartan, Atorvastatin, and Furosemide. A kidney biopsy was performed which demonstrated unremarkable light microscopy and immunofluorescence and widespread podocyte-foot process effacement. These biopsy findings were interpreted to be consistent with minimal change disease. She was started on Prednisone at 1 mg/kg/day with continuation of both Losartan and Atorvastatin. Six weeks after, the patient achieved complete remission with resolution of both hypoalbuminemia and dyslipidemia. She also reports no further recurrence of edema. Case 2 A 61-year-old Filipino male with a history of type 2 diabetes mellitus, hypertension, dyslipidemia and mild COVID-19 infection 4 months prior now presented with diarrhea. A routine COVID-19 RT-PCR swab revealed a re-infection. Physical examination noted bipedal edema. Further workup demonstrated a serum creatinine 3.39 mg/dL, urine RBC 2/HPF and urine ACR 2.6 g/g. Serologic tests were negative. He was diagnosed with Nephrotic Syndrome and underwent kidney biopsy. Findings showed an unremarkable light microscopy and immunofluorescence with widespread podocyte-foot process effacement. These findings were found to be consistent with minimal change disease and acute tubular injury. He was started on Prednisone (1 mg/kg/day), Losartan, Furosemide and Atorvastatin. Eight weeks later, the patient achieved complete remission with resolution of edema. CONCLUSION It is currently suspected that APOL1 risk variants found in reported cases of COVID-19-associated glomerulopathies are underlying toxic gain-of-function mutations that drive kidney disease.2 It is interesting to note that APOL1 renal risk variants are found exclusively in African-derived chromosomes and are rarely found among European or Asian chromosomes.3 Even though an APOL1 genotyping was not performed, our case reports provide the first examples of MCD among individuals without a high-risk genotype (APOL1) by epidemiology and enlarge the literature on MCD in COVID-19. We posit that there may be other underlying predispositions or mechanisms that may be driving glomerulopathy formation among COVID-19 patients aside from their inherent APOL 1 risk. Both of our patients were started on steroid therapy with a tapering regimen and achieved complete remission on subsequent follow-up. Existing reports suggest that most cases of COVID-19-associated MCD will often achieve resolution of AKI and proteinuria with steroid therapy, even in those with high-risk APOL1 genotype, emphasizing the need for an accurate histologic classification.4

Treatment of post-transplant recurrent FSGS in children using plasmapheresis and augmentation of immunosuppression

BackgroundUp to 60% of pediatric renal transplant recipients with end-stage renal disease due to primary focal and segmental glomerulosclerosis (FSGS) may develop recurrent disease. Such recurrence is associated with poor prognosis if no remission is achieved. We report a single center experience with a protocol based on plasmapheresis and increased immunosuppression that resulted in a high long-lived remission rate.MethodsThis retrospective cohort study included consecutive pediatric renal transplant patients with recurrent FSGS treated with a standardized protocol using plasmapheresis and cyclophosphamide to supplement usual post-transplant immunosuppression with calcineurin inhibitors and steroids. Relapse was defined as urinary protein/creatinine ratio > 1.0 g/g and remission as < 0.5 g/g.ResultsSeventeen patients with FSGS recurrence post-transplant were treated. All had therapy resistant FSGS in native kidneys and had been on dialysis from 4 to 10 years. Of the 17, one died perioperatively from a pulmonary thromboembolism. Fifteen others achieved a complete remission within 3 months of treatment for FSGS recurrence. After a median follow-up period of 4 years, there were no recurrences of significant proteinuria. One patient achieved remission with rituximab.ConclusionThe addition of plasmapheresis and cyclophosphamide to a calcineurin- and steroid-based immunosuppression regime was highly successful in inducing high remission rates with recurrent FSGS. Prospective trials are needed to evaluate further the efficacy of increased immunosuppression along with plasmapheresis in this setting.

Nephrotic syndrome: Current understanding and future therapies

Advances in basic and clinical research have improved ourunderstanding of the pathomechanisms underlying nephrotic syndrome caused by minimal change disease (MCD) and focal and segmental glomerulosclerosis (FSGS). These advances are reflected in the new 2021 KDIGO-Guidelines, which emphasize the clear distinction between primary, secondary and genetic causes. Proper classification is critical, as it directly affects the therapy of choice. While glucocorticoids still play a central in inducing remission in primary forms, calcineurin inhibitors, mycophenolate mofetil, cyclophosphamide and rituximab (off label) are viable adjuncts/alternatives to reduce or replace glucocorticoids in case of side effects or contraindications. Since SGLT-2-inhibitors have shown renoprotective effects in non-diabetic patients and may help to reduce proteinuria, they should be considered in all (adult) patients with chronic kidney disease, including MCD and FSGS patients. In the near future, Sparsentan, an endothelin type A and angiotensin receptor blocker may be added to the growing arsenal of proteinuria-reducing agents, with a phase 3 trail expected to be completed in late 2022. Finally, we recommend the inclusion of all MCD/FSGS patients in clinical registries (e. g. FOrMe Registry in Germany) to ensure adequate therapy and genetic testing if indicated. In addition, national registries are an invaluable source of clinical data that helps to refine our therapies towards individualized medicine.

POS-363 TREATMENT WITH RECOMBINANT MUTATED HUMAN ANGIOPOIETIN-LIKE 4 AMELIORATES RELAPSE OF PRIMARY GLOMERULAR DISEASES INDUCED BY A COMMON COLD

In nearly 70% of patients with primary glomerular diseases like Minimal Change Disease (MCD) and Focal and Segmental Glomerulosclerosis (FSGS), relapse is preceded by a common cold. In addition, most patients with MCD have a chronic atopic state. Recent studies from our group (Mace et al Kidney International 2020) showed the importance of low podocyte ZHX2 expression in the pathogenesis of MCD and FSGS. At least half of all Common Colds are caused by Rhinovirus infections. Using different components innate and adaptive immunity, the circulating Rhinovirus A and B receptor, and a marker of chronic atopy, we developed and tested a Rhinovirus cytokine storm cocktail in Zhx2 deficient BALB/cJ mice.

An Integrative in silico Study to Discover Key Drivers in Pathogenicity of Focal and Segmental Glomerulosclerosis

Background: Focal and segmental glomerulosclerosis (FSGS) is a clinical-pathologic condition marked by segmental and localized glomerular damages. Despite investigations, the molecular mechanisms behind FSGS development remain to be more clarified. By a comprehensive analysis of an FSGS-related array set, the aim of this study was to unravel the top pathways and molecules involved in the pathogenesis of this disorder. Methods: FSGS-related microarray dataset (GSE129973) from the Gene Expression Omnibus database was quality checked, analyzed, and its differentially expressed genes (DEGs) (log2 fold change > 1) were used for the construction of a protein-protein interaction (PPI) network (STRING). The degree of centrality was considered to select the hub molecules in the network. The weighted gene co-expression network analysis (WGCNA) was utilized to construct co-expression modules. Hub molecules were selected based on module membership and gene significance values in the disease’s most correlated module. After spotting the key molecules considering both strategies, their expression pattern was checked in other FSGS microarray datasets. Gene ontology and Reactome pathway enrichment analyses were performed on the DEGs of the related module. Results: After quality checking, normalization, and analysis of the dataset, 5,296 significant DEGs, including 2,469 upregulated and 2,827 downregulated DEGs were identified. The WGCNA algorithm clustered the DEGs into nine independent co-expression modules. The disease most correlated module (black module) was recognized and considered for further enrichment analysis. The immune system, cell cycle, and vesicle-mediated transports were among the top enriched terms for the identified module’s DEGs. The immune system, cell cycle, and vesicle-mediated transports were among the top enriched terms for the black module’s DEGs. The key molecules (BMP-2 and COL4A1) were identified as common hub molecules extracted from the two methods of PPI and the co-expressed networks. The two identified key molecules were validated in other FSGS datasets, where a similar pattern of expression was observed for both the genes. Conclusions: Two hub molecules (BMP-2 and COL4A) and some pathways (vesicle-mediated transport) were recognized as potential players in the pathogenesis of FSGS.

Prevalence of Renal Failure in Children and the Need for Dialysis in Paediatric Nephrology in a Developing Country

Background: Renal failure is among the major visceral failures responsible for morbidity and mortality in children. Epidemiological data on renal failure in children are limited in sub-Saharan Africa, including Senegal. We conducted this study to assess the prevalence of renal failure (RF) and the need for dialysis in the paediatric nephrology unit. Patients and methods: This was a retrospective and descriptive study in the pediatric nephrology unit from 1st January 2020 to 30 June 2021, including children with acute or chronic RF. The need for dialysis was judged to be met by its effectiveness in face of an indication. The data collected were analysed on sphinx plus 2017 software. Results: The prevalence of RF was 60% (n/N = 132/220). RF was acute in 59% (n/N = 78/132) of cases. The mean age was 6.53 ± 4.77 years with a sex ratio of 1.8. The mean serum creatinine level was 27.22 mg/L (240.9 μmol/L) and BUN at 0.85 g/L. The aetiologies were dominated by prerenal AKI (Acute Kidney Injury) complicating nephrotic syndrome (NS) in 37.2% (n/N = 29/78) and dehydration due to stomach flu in 17.6% (n/N = 9/51). Acute post-infectious glomerulonephritis including group A streptococcus and plasmodium falciparum accounted for 16.7% (n = 13/78) of intrinsic AKI. The need for dialysis was unmet in 50% (n/N = 7/14) with a mortality of 14.1% (n/N = 11/78). The mean age of the patients with chronic RF was 8.68 ± 4.74 years with a sex ratio of 2.6. The mean serum creatinine level was 36.56 mg/L (323.5 μmol/L) and the BUN level was 0.99 g/L. Half of the children were classified as having CKD stage II (early stage). The aetiologies were dominated by primary focal and segmental glomerulosclerosis (FSGS), 53.7% (n/N = 29/54), renal hypoplasia, 22.2% (n/N = 12/54) and reflux nephropathy, 29.4% (n/N = 5/17). The need for dialysis was unmet in 46.1% (n/N = 6/13). The overall mortality of chronic kidney disease (CKD) with RF was 29.6% (n/N = 8/27). Conclusion: The prevalence of RF was high in the unit. Most aetiologies of AKI were accessible to prevention. Only half of the children had access to free dialysis, hence the need for a dedicated pilot dialysis centre.

CD44-negative parietal-epithelial cell staining in minimal change disease: association with clinical features, response to corticosteroids and kidney outcome.

ABSTRACTBackground Activation of parietal–epithelial cells (PECs) with neo-expression of CD44 has been found to play a relevant role in the development of focal and segmental glomerulosclerosis (FSGS). The aim of this study was to analyse whether the expression of CD44 by PECs in biopsies of minimal change disease (MCD) is associated with the response to corticosteroids, with kidney outcomes and/or can be considered an early sign of FSGS.MethodsThis multicentric, retrospective study included paediatric and adult patients with MCD. Demographic, clinical and biochemical data were recorded, and biopsies were stained with anti-CD44 antibodies. The association between PECs, CD44 expression and the response to corticosteroids, and kidney outcomes were analysed using logistic, Kaplan–Meier and Cox regression analyses.Results A total of 54 patients were included: 35 (65%) <18 years and 19 (35%) adults. Mean follow-up was 68.3 ± 37.9 months. A total of 19/54 patients (35.2%) showed CD44-positive staining. CD44-positive patients were younger (14.5 ± 5 versus 21.5 ± 13, P = 0.006), and showed a higher incidence of steroid-resistance [11/19 (57.8%) versus 7/35 (20%), P = 0.021; odds ratio: 5.5 (95% confidence interval 1.6–18), P = 0.007] and chronic kidney disease [9/19 (47.3%) versus 6/35 (17.1%), P = 0.021; relative risk: 3.01 (95% confidence interval 1.07–8.5), P = 0.037]. Follow-up re-biopsies of native kidneys (n = 18), identified FSGS lesions in 10/12 (83.3%) of first-biopsy CD44-positive patients versus 1/6 (16.7%) of first-biopsy CD44-negative patients (P = 0.026).Conclusions In patients with a light microscopy pattern of MCD, CD44-positive staining of PECs is associated with a higher prevalence of steroid resistance and worse kidney outcomes, and can be considered an early sign of FSGS.