Childhood nephrotic syndrome—current and future therapies

Mechanistic insights into Qiteng Xiaozhuo Granules' regulation of autophagy for chronic glomerulonephritis treatment: Serum pharmacochemistry, network pharmacology, and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Qiteng Xiaozhuo Granules (QTXZG), a traditional Chinese medicine prescription, is widely acknowledged for its therapeutic efficacy and lack of discernible toxicity in clinical practice, substantiating its potential in the treatment of chronic glomerulonephritis (CGN). Nevertheless, the specific effectiveness and underlying mechanisms of QTXZG remain insufficiently explored.

AIM OF THE STUDY

The purpose of this study was to explore the mechanism of the QTXZG in the treatment of CGN via targeting autophagy based on serum pharmacochemistry, network pharmacology, and experimental validation.

METHODS

Serum samples from SD rats orally administered QTXZG were analyzed using UPLC-QE/MS to identify contained compounds. Network and functional enrichment analyses elucidated QTXZG's targets and biological mechanisms. Reliability was ensured through molecular docking, in vivo and in vitro experiments.

RESULTS

After oral administration of QTXZG, 39 enriched compounds in serum samples collected 1 h later were identified as potential active agents, with 508 potential targets recognized as QTXZG-specific targets. Through integration of various databases, intersection analysis of QTXZG targets, CGN-related genes, and autophagy-related targets identified 10 core autophagy-related targets for QTXZG in CGN. GO and KEGG analyses emphasized their roles in autophagy, inflammation, and immune processes, particularly emphasizing the enrichment of the AMPK/mTOR signaling pathway. Molecular docking results demonstrated strong binding affinities between QTXZG's key compounds and the predicted core targets. In animal experiments, QTXZG was found to ameliorate renal tissue damage in CGN model mice, significantly reducing serum creatinine (Scr) and blood urea nitrogen (BUN) levels. Importantly, both animal and cell experiments revealed QTXZG's ability to decrease excessive ROS and inflammatory factor release in mesangial cells. Furthermore, in vitro and in vivo experiments confirmed QTXZG's capacity to upregulate Beclin1 and LC3II/I expression, decrease p62 expression, and induce CGN autophagy through modulation of the AMPK/mTOR pathway.

CONCLUSIONS

This study indicated that QTXZG can induce autophagy in CGN by affecting the AMPK/mTOR pathway, and induction of autophagy may be one of the possible mechanisms of QTXZG's anti-CGN.

Effects of tacrolimus on proteinuria in Chinese and Indian patients with idiopathic membranous nephropathy: the results of machine learning study

PURPOSE

The present study aims to explore the effects of tacrolimus on proteinuria in patients with idiopathic membranous nephropathy (IMN) and recommend an appropriate dosage schedule via machine learning method.

METHODS

The Emax model was constructed to analyze the effects of tacrolimus on proteinuria in patients with IMN. Data were mined from published literature and machine learning was built up with Emax model, among which the efficacy indicator was proteinuria change rates from baseline. 463 IMN patients were included for modeling, and tacrolimus therapeutic window concentrations were 4-10 ng/ml.

RESULTS

In machine learning model, the Emax from tacrolimus effecting proteinuria in IMN patients was -72.7%, the ET50 was 0.43 months, and the time to achieving 25% Emax, 50% Emax, 75% Emax, and 80% (plateau) Emax of tacrolimus on proteinuria in patients with IMN were 0.15, 0.43, 1.29, and 1.72 months, respectively.

CONCLUSION

For achieving better therapeutic effects from tacrolimus on proteinuria in patients with IMN, tacrolimus concentration range need to be maintained at 4-10 ng/ml for at least 1.72 months.

Glucocorticoid- and pioglitazone-induced proteinuria reduction in experimental NS both correlate with glomerular ECM modulation

Idiopathic nephrotic syndrome (NS) is a common glomerular disease. Although glucocorticoids (GC) are the primary treatment, the PPARγ agonist pioglitazone (Pio) also reduces proteinuria in patients with NS and directly protects podocytes from injury. Because both drugs reduce proteinuria, we hypothesized these effects result from overlapping transcriptional patterns. Systems biology approaches compared glomerular transcriptomes from rats with PAN-induced NS treated with GC vs. Pio and identified 29 commonly regulated genes-of-interest, primarily involved in extracellular matrix (ECM) remodeling. Correlation with clinical idiopathic NS patient datasets confirmed glomerular ECM dysregulation as a potential mechanism of injury. Cellular deconvolution in silico revealed GC- and Pio-induced amelioration of altered genes primarily within podocytes and mesangial cells. While validation studies are indicated, these analyses identified molecular pathways involved in the early stages of NS (prior to scarring), suggesting that targeting glomerular ECM dysregulation may enable a future non-immunosuppressive approach for proteinuria reduction in idiopathic NS.

N6-methyladenosine (m6A) methylation in kidney diseases: Mechanisms and therapeutic potential

The N6-methyladenosine (m6A) modification is regulated by methylases, commonly referred to as "writers," and demethylases, known as "erasers," leading to a dynamic and reversible process. Changes in m6A levels have been implicated in a wide range of cellular processes, including nuclear RNA export, mRNA metabolism, protein translation, and RNA splicing, establishing a strong correlation with various diseases. Both physiologically and pathologically, m6A methylation plays a critical role in the initiation and progression of kidney disease. The methylation of m6A may also facilitate the early diagnosis and treatment of kidney diseases, according to accumulating research. This review aims to provide a comprehensive overview of the potential role and mechanism of m6A methylation in kidney diseases, as well as its potential application in the treatment of such diseases. There will be a thorough examination of m6A methylation mechanisms, paying particular attention to the interplay between m6A writers, m6A erasers, and m6A readers. Furthermore, this paper will elucidate the interplay between various kidney diseases and m6A methylation, summarize the expression patterns of m6A in pathological kidney tissues, and discuss the potential therapeutic benefits of targeting m6A in the context of kidney diseases.

Changes in Patterns of Infection Associated with Pediatric Idiopathic Nephrotic Syndrome: A Single-Center Experience in Japan

OBJECTIVE

We studied infection rates and risk factors for infection in current patients with idiopathic nephrotic syndrome (INS).

STUDY DESIGN

This retrospective cohort study included the clinical data for children with diagnosed INS in our center between January 2010 and December 2020. The infection rates and risk factors were analyzed.

RESULTS

We enrolled 187 patients, including 85 cases with steroid-dependent/frequently relapsing nephrotic syndrome and 45 with steroid-resistant nephrotic syndrome. Infection was observed a total of 84 times in 55 patients (95.5 per 1000 person-years). Pneumonia was the most common infection (21 cases, 23.9 per 1000 person-years), followed by febrile neutropenia (12 cases, 13.7 per 1000 person-years), whereas peritonitis and bacteremia were observed in only 3 and 2 cases, respectively. The multivariate analyses by logistic regression showed that rituximab treatment was significantly associated with infections in pediatric INS (P = .001). The infection rate during the B-cell-depleted state with immunosuppressants (318 per 1000 person-years) was greater than that with normal B-cell count with immunosuppressants (109 per 1000 person-years) or without immunosuppressants (76 per 1000 person-years).

CONCLUSION

Common infections, such as peritonitis and bacteremia, decreased, whereas infections associated with medication (eg, rituximab) increased. The rate of infection increases during B-cell depletion after treatments with rituximab and other immunosuppressants.

Metabolomics Profiling of Nephrotic Syndrome towards Biomarker Discovery

Nephrotic syndrome (NS) is a kidney illness characterized by excessive proteinuria, hypoalbuminemia, edema, and hyperlipidemia, which may lead to kidney failure and necessitate renal transplantation. End-stage renal disease, cardiovascular issues, and mortality are much more common in those with NS. Therefore, the present study aimed to identify potential new biomarkers associated with the pathogenesis and diagnosis of NS. The liquid chromatography–mass spectrometry (LC–MS) metabolomics approach was applied to profile the metabolome of human serum of patients with NS. A total of 176 metabolites were significantly altered in NS compared to the control. Arginine, proline, and tryptophan metabolism; arginine, phenylalanine, tyrosine, and tryptophan biosynthesis were the most common metabolic pathways dysregulated in NS. Furthermore, alanyl-lysine and isoleucyl-threonine had the highest discrimination between NS and healthy groups. The candidate biomarkers may lead to understanding the possible metabolic alterations associated with NS and serve as potential diagnostic biomarkers.

Optimization of initial dose regimen of tacrolimus in paediatric lung transplant recipients based on Monte Carlo simulation

WHAT IS KNOWN AND OBJECTIVES

The initial tacrolimus dose regimen in paediatric lung transplant recipients is unknown. The present study optimized the initial tacrolimus dose regimen for paediatric lung transplant recipients.

METHODS

This study was based on a published population pharmacokinetic model of tacrolimus in lung transplant recipients and used Monte Carlo simulations to recommend an initial dose regimen of tacrolimus in paediatric lung transplant recipients.

RESULTS

Without voriconazole, the tacrolimus doses recommended for paediatric lung transplant recipients who were not CYP3A5*1 carriers were 0.02, 0.03, and 0.04 mg/kg/day, split into two doses, for weights of 10-16, 16-30, and 30-40 kg, respectively. For paediatric lung transplant recipients who were CYP3A5*1 carriers, the tacrolimus doses of 0.03, 0.04, 0.05, and 0.06 mg/kg/day, split into two doses, were recommended for weights of 10-16, 16-25, 25-30, and 30-40 kg, respectively. With voriconazole, the tacrolimus dose recommended for paediatric lung transplant recipients who were not CYP3A5*1 carriers was 0.02 mg/kg/day, split into two doses, for weights of 10-40 kg. For paediatric lung transplant recipients who were CYP3A5*1 carriers, tacrolimus doses of 0.02 and 0.03 mg/kg/day, split and two doses, were recommended for weights of 10-24 and 24-40 kg, respectively.

WHAT IS NEW AND CONCLUSIONS

This study developed tacrolimus dose regimens for the first time for paediatric lung transplant recipients using Monte Carlo simulation and optimized initial dosage in paediatric lung transplant recipients.

"Clinical Efficacy of Mycophenolate Mofetil versus Levamisole Therapy in Frequently Relapsing and Steroid Dependent Childhood Nephrotic Syndrome" - A retrospective comparative analysis

BACKGROUND

Children with Frequently relapsing (FR) or Steroid dependent (SD) Nephrotic Syndrome (NS) often develop side effects of corticosteroids. Various steroid-sparing agents are in practice, but only a few studies exist so far which have compared the safety and efficacy of these two commonly used agents.

METHODS

We did a retrospective medical records review of children with FRNS or SDNS who had Levamisole or MMF as a steroid-sparing agent with a minimum follow-up period of 12 months. The aim was to compare the course of our patients on MMF and Levamisole. Our primary objective was to determine the number of children in sustained remission and those with the infrequently relapsing course on Levamisole and MMF and, the median time to relapse in months in the two groups. The secondary objective was to compare time to first relapse and number of relapses in FRNS and SDNS group children on MMF and Levamisole.

RESULTS

A total of 88 children (34% female) with diagnosis FR/SDNS (44 each) were included in the study. Thirty-nine patients took Levamisole, while forty-nine received MMF therapy. The median age of presentation at the relapsing course was 4.2 years. The proportion of children with sustained remission or infrequent relapsing (IFR) course on MMF was 73.6%, compared to 48.71% on Levamisole (p-value 0.015). Also, the median time to first relapse was 12 months (24, 1.5) and 4.5 months (24, 1) on respective medications.

CONCLUSIONS

Clinical outcome was superior in the MMF group than Levamisole, especially in SDNS patients, and also MMF was more efficacious in maintaining sustained remission. This article is protected by copyright. All rights reserved.

Case Report: The Application of Dupilumab in Atopic Dermatitis Children Complicated With Nephrotic Syndrome

Nephrotic syndrome (NS) tends to be more common in patients with history of allergies. Atopic dermatitis (AD) is one of the most common allergic diseases in children. Dupilumab, a dual IL-4 and IL-13 inhibitor, has been widely used to treat AD patients. However, the efficacy and safety of Dupilumab in NS is unclear. We reported two AD patients with NS comorbidities treated with Dupilumab. The outcomes showed the good control of NS and less systemic steroids and/or immunosuppressive agents use during the Dupilumab treatment period, accompanied by significant relief of AD symptoms. We suggest prospective pilot studies and randomized controlled trials could be carried out to validate the efficacy and safety of Dupilumab in the treatment of NS patients.

The immunopathogenesis of idiopathic nephrotic syndrome: a narrative review of the literature

Idiopathic nephrotic syndrome (INS) is a common glomerular disease in childhood, and the immunological involvement in the pathogenesis of non-genetic INS, although not fully elucidated, is evident. This narrative review aims to offer a concise and in-depth view of the current knowledge on the immunological mechanisms of the development of INS as well as the role of the immunological components of the disease in the responsiveness to treatment. T cell immunity appears to play a major role in the INS immunopathogenesis and has been the first to be linked to the disease. Various T cell immunophenotypes are implicated in INS, including T-helper-1, T-helper-2, T-helper-17, and T regulatory cells, and various cytokines have been proposed as surrogate biomarkers of the disease; however, no distinct T helper or cytokine profile has been conclusively linked to the disease. More recently, the recognition of the role of B cell mediated immunity and the various B cell subsets that are dysregulated in patients with INS have led to new hypotheses on the underlying immunological causes of INS. Finally, the disambiguation of the exact mechanisms of the INS development in the future may be the key to the development of more targeted personalized approaches in managing INS.

CONCLUSIONS

INS demonstrates particularly interesting immunopathogenetic pathways, in which multiple interactions between T cell and B cell immunity and the podocyte are involved. The disambiguation of these pathways will provide promising novel therapeutic targets in INS.

WHAT IS KNOWN

• INS is the most common glomerular disease in the paediatric population, and its onset and relapses have been linked to various immunological triggers. • Multiple immunological mechanisms have been implicated in the pathogenesis of INS; however, no single distinct immunological profile has been recognized.

WHAT IS NEW

• Th17 cells and Treg cells play an important role in the immune dysregulation in INS. • Transitional B cell levels as well as the transitional/memory B cell ratio have been correlated to nephrotic relapses and have been proposed as biomarkers of INS relapses in SSNS patients.

Alteration of N6-methyladenosine epitranscriptome profile in lipopolysaccharide-induced mouse mesangial cells

N6-Methyladenosine (m6A) is the most prevalent internal modification of messenger RNA (mRNA) in eukaryotes. The underlying molecular mechanisms of m6A modification in chronic glomerulonephritis (CGN) remain unexplored. Here, we performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) analyses to assess the alterations of epitranscriptome-wide m6A profile in lipopolysaccharide (LPS)-induced mouse mesangial cells (MMC). The results of our data showed 2153 significantly differential m6A peaks and 358 significantly differentially expressed genes. Furthermore, integrated analysis from MeRIP-seq and RNA-seq identified a total of 64 genes with differential m6A modification and expressed levels, of which 5 genes displayed hypermethylation and upregulation, 42 genes displayed hypermethylation and downregulation, 11 genes displayed hypomethylation and upregulation, and 8 genes displayed hypomethylation and downregulation. Many of them (including Fosl1, Sorbs1, Ambp, Fgfr3, Nedd9, Fgg, Trim13, Fgf22, Mylk, and Muc6) are implicated in the regulation of the immune and inflammatory response. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis found that differential 64 genes were mainly enriched in fatty acid oxidation, apoptosis signaling pathway, complement and coagulation cascades, and PPAR signaling pathway. Together, our study provided a new perspective on the understanding of molecular features of m6A modification in CGN pathogenic pathogenesis.

A Family Segregating Lethal Primary Coenzyme Q10 Deficiency Due to Two Novel COQ6 Variants

Primary coenzyme Q10 deficiency-6 (COQ10D6), as a rare autosomal recessive disease caused by COQ6 mutations, is characterized by progressive infantile-onset nephrotic syndrome resulting in end-stage renal failure and sensorineural hearing loss. Here, we report two Chinese siblings with COQ10D6 who primarily presented with severe metabolic acidosis, proteinuria, hypoalbuminemia, growth retardation, and muscle hypotonia and died in early infancy. Using whole-exome sequencing and Sanger sequencing, we identified two rare recessive nonsense mutations in the COQ6 gene segregating with disease in affected family members: c.249C > G (p.Tyr83Ter) and c.1381C > T (p.Gln461Ter), resulting in two truncated protein products. Both mutations are located in a highly conserved area and are predicted to be pathogenic. Indeed, the death of our patients in early infancy indicates the pathogenicity of the p.Tyr83Ter and p.Gln461Ter variants and highlights the significance of the two variants for COQ6 enzyme function, which is necessary for the biosynthesis of coenzyme Q10. In conclusion, we discovered a novel compound heterozygous pathogenic variant of the COQ6 gene as a cause of severe COQ10D6 in the two siblings. Based on the clinical history and genetic characteristics of the patients, our cases expand the genotypic spectrum of COQ10D6 and highlight the heterogeneity and severity of clinical features associated with COQ6 mutations. For patients with clinical manifestations suggestive of COQ10D6, early testing for COQ6 mutations is beneficial for disease diagnosis and therapeutic interventions as well as disease prevention in future generations.

Idiopathic Nephrotic Syndrome in Pediatrics: An Up-to-date

BACKGROUND

Idiopathic or Primary Nephrotic Syndrome (INS) is a common glomerular disease in pediatric population, characterized by proteinuria, edema and hypoalbuminemia with variable findings in renal histopathology.

OBJECTIVE

This review aims to summarize current data on the etiopathogenesis diagnosis, protocols of treatment and potential therapeutic advances in INS.

METHODS

This narrative review searched for articles on histopathology, physiopathology, genetic causes, diagnosis and treatment of INS in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

INS is caused by an alteration in the permeability of the glomerular filtration barrier with unknown etiology. There are several gaps in the etiopathogenesis, response to treatment and clinical course of INS that justify further investigation. Novel advances include the recent understanding of the role of podocytes in INS and the identification of genes associated with the disease. The role of immune system cells and molecules has also been investigated. The diagnosis relies on clinical findings, laboratory exams and renal histology for selected cases. The treatment is primarily based on steroids administration. In case of failure, other medications should be tried. Recent studies have also searched for novel biomarkers for diagnosis and alternative therapeutic approaches.

CONCLUSION

The therapeutic response to corticosteroids still remains the main predictive factor for the prognosis of the disease. Genetic and pharmacogenomics tools may allow the identification of cases not responsive to immunosuppressive medications.

The role of the immune system in idiopathic nephrotic syndrome

Idiopathic nephrotic syndrome (INS) in children is characterized by massive proteinuria and hypoalbuminemia and usually responds well to steroids. However, relapses are frequent, which can require multi-drug therapy with deleterious long-term side effects. In the last decades, different hypotheses on molecular mechanisms underlying INS have been proposed and several lines of evidences strongly indicate a crucial role of the immune system in the pathogenesis of non-genetic INS. INS is traditionally considered a T-cell-mediated disorder triggered by a circulating factor, which causes the impairment of the glomerular filtration barrier and subsequent proteinuria. Additionally, the imbalance between Th17/Tregs as well as Th2/Th1 has been implicated in the pathomechanism of INS. Interestingly, B-cells have gained attention, since rituximab, an anti-CD20 antibody demonstrated a good therapeutic response in the treatment of INS. Finally, recent findings indicate that even podocytes can act as antigen-presenting cells under inflammatory stimuli and play a direct role in activating cellular pathways that cause proteinuria. Even though our knowledge on the underlying mechanisms of INS is still incomplete, it became clear that instead of a traditionally implicated cell subset or one particular molecule as a causative factor for INS, a multi-step control system including soluble factors, immune cells, and podocytes is necessary to prevent the occurrence of INS. This present review aims to provide an overview of the current knowledge on this topic, since advances in our understanding of the immunopathogenesis of INS may help drive new tailored therapeutic approaches forward.

Exploring the mechanism of Jianpi Qushi Huayu Formula in the treatment of chronic glomerulonephritis based on network pharmacology

This study was to explore the effective components, potential targets, and pathways of Jianpi Qushi Huayu Formula (JQHF) for the treatment of chronic glomerulonephritics (CGN). First, the Chinese Medicine System Pharmacology Database and Analysis Platform (TCMSP), GeneCards, and OMIM databases were used to collect the major active components of JQHF and potential therapeutic targets of CGN. Then, functional enrichment analysis was performed to clarify the mechanisms of the JQHF on CGN. Subsequently, molecular docking was simulated to assess the binding ability of key targets and major active components. Finally, quantitative real-time PCR and western blot were performed for experimental verification of cells in vitro. A total of 55 active ingredients contained and 220 putative identified targets were screened from JQHF, of which 112 overlapped with the targets of CGN and were considered potential therapeutic targets. Then, we found quercetin and kaempferol are two key ingredients of JQHF, which may act on the top 10 screened targets of PPI, affecting CGN through related signal transduction pathways. Subsequently, molecular docking predicted that quercetin and kaempferol bind firm with the top 10 core targets of PPI. Further experiment verified some results and showed that JQHF has protected glomerular mesangial cells from lipopolysaccharide-induced inflammation by inhibiting expressions of IL6, TNF-α, and AKT1, and activating expressions of VEGFA. Based on network pharmacology, we explored the multi-component, multi-target, and multi-pathway characteristics of JQHF in treating CGN, and found that JQHF could act on IL6, TNF-α, VEGFA, and AKT1 to exert the effect of anti-CGN, which provided new ideas and methods for further research on the mechanism of JQHF in treating CGN.

Zataria multiflora and its main ingredient, carvacrol, affect on the renal function, histopathological, biochemical and antioxidant parameters in adriamycin-induced nephrotic rats

Oxidative stress has a major role in the nephrosis. In the present study, the effects of hydroalcoholic extract of Zataria multiflora (ZM) and carvacrol (CAR) were evaluated on the renal damage induced by adriamycin (ADR). The animals accidentally divided into four groups including: Control, ADR, ZM + ADR and CAR + ADR. The renal tissue, urine, and blood samples subjected to biochemical markers and histopathological evaluation. ADR significantly decreased glomerular filtration rate (GFR) while escalated urine protein excretion as well as protein clearance (p < .01 to p < .001). Also, ADR significantly reduced the antioxidants and boosted the malondialdehyde (MDA) compared to the control (p < .05 to p < .01). In groups treated by ZM and CAR, GFR, and antioxidants significantly increased, whereas urine protein excretion and MDA decreased (p < .05 to p < .001). ZM and CAR induced an improvement in ADR-induced renal damage by improving renal function as well as antioxidant activity.

The potential mechanism of Astragali Radix in the treatment of children with nephrotic syndrome

BACKGROUND

The molecular mechanism of Astragali Radix in the treatment of children with nephrotic syndrome (NS) is unclear. This study aimed to use network pharmacology to explore this potential mechanism.

METHODS

The Traditional Chinese Medicine Systems Pharmacology (TCMSP) database was used to identify the main active ingredients of Astragali Radix. The PharmMapper, Online Mendelian Inheritance in Man (OMIM), and GeneCards databases were then used to identify the active ingredients of Astragali Radix. The String database and Cytoscape software were used to construct the protein-protein network. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using DAVID Database.

RESULTS

In the TCMSP Database, a total of 20 chemical constituents of Astragali Radix were screened. After removing the duplicates and false positive genes, 394 targets of these active ingredients were obtained from PharmMapper. By comparing the NS-related genes in the GeneCards and OMIM Databases, a total of 39 potential NS-related targets were ultimately identified. The protein-protein-interaction network included 39 nodes and 366 edges. The top 5 proteins were albumin (ALB), serine/threonine kinase (AKT1), epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK), and matrix metallopeptidase 9 (MMP9). The GO analysis showed that the target genes were mainly involved in biological processes (e.g., signal transduction, the positive regulation of cell proliferation, and the positive regulation of migration). The cellular components included a plasma membrane, extracellular exosome, and extracellular space. The molecular functions included protein binding, zinc-ion binding, protein tyrosine kinase activity, and enzyme binding. The KEGG analysis showed that the treatment of NS by Astragali Radix mainly involved pathways in cancer, proteoglycans in cancer, the phosphatidylinositol 3-kinase and protein kinase B (PI3K-Akt) signaling pathway, the rennin-angiotensin-system (Ras) signaling pathways, and Forkhead box protein O1 (FoxO) signaling pathways.

CONCLUSIONS

In the present study, the network pharmacology method was used to explore the potential targets and pathways of Astragali Radix in the treatment of NS. We also provided future research directions for the treatment of NS with a complex pathogenesis.

A Novel Model for Nephrotic Syndrome Reveals Associated Dysbiosis of the Gut Microbiome and Extramedullary Hematopoiesis

Glomerular kidney disease causing nephrotic syndrome is a complex systemic disorder and is associated with significant morbidity in affected patient populations. Despite its clinical relevance, well-established models are largely missing to further elucidate the implications of uncontrolled urinary protein loss. To overcome this limitation, we generated a novel, inducible, podocyte-specific transgenic mouse model (Epb41l5^fl/fl*Nphs1-rtTA-3G*tetOCre), developing nephrotic syndrome in adult mice. Animals were comprehensively characterized, including microbiome analysis and multiplexed immunofluorescence imaging. Induced knockout mice developed a phenotype consistent with focal segmental glomerular sclerosis (FSGS). Although these mice showed hallmark features of severe nephrotic syndrome (including proteinuria, hypoalbuminemia and dyslipidemia), they did not exhibit overt chronic kidney disease (CKD) phenotypes. Analysis of the gut microbiome demonstrated distinct dysbiosis and highly significant enrichment of the Alistipes genus. Moreover, Epb41l5-deficient mice developed marked organ pathologies, including extramedullary hematopoiesis of the spleen. Multiplex immunofluorescence imaging demonstrated red pulp macrophage proliferation and mTOR activation as driving factors of hematopoietic niche expansion. Thus, this novel mouse model for adult-onset nephrotic syndrome reveals the significant impact of proteinuria on extra-renal manifestations, demonstrating the versatility of this model for nephrotic syndrome-related research.

Serum and urine ANGPTL8 expression levels are associated with hyperlipidemia and proteinuria in primary nephrotic syndrome

Background

This study aimed to investigate the expression characteristics of ANGPTL8 in patients with primary nephrotic syndrome and its possible correlation with hyperlipidemia and proteinuria.

Methods

ANGPTL8 levels were determined using an enzyme-linked immunosorbent assay in 133 subjects with PNS and 60 healthy controls.

Results

Compared with healthy controls, subjects with primary nephrotic syndrome had higher levels of serum and urine ANGPTL8 (P < 0.001). In primary nephrotic syndrome patients, serum ANGPTL8 was positively correlated with cholesterol (r = 0.209, P < 0.05) and triglycerides (r = 0.412, P < 0.001), while there was no correlation with 24 hUTP. Urine ANGPTL8 was positively correlated with high-density lipoprotein cholesterol (r = 0.181, P < 0.05) and was significantly negatively correlated with creatinine (r = − 0.323, P < 0.001), eGFR (r = − 0, P < 0.001) and 24 hUTP (r = − 0.268, P = 0.002). Interestingly, the urine ANGPTL8 concentrations in membranous nephropathy and mesangial proliferative glomerulonephritis pathological types were different.

Conclusions

Serum and urine ANGPTL8 levels in primary nephrotic syndrome patients were correlated with blood lipid levels and proteinuria, respectively, suggesting that ANGPTL8 may play a role in the development of primary nephrotic syndrome hyperlipidemia and proteinuria.

All-case Japanese post-marketing surveillance of the real-world safety and efficacy of rituximab treatment in patients with refractory nephrotic syndrome

BACKGROUND

Rituximab is conditionally approved in Japan for use in patients with refractory nephrotic syndrome. To meet the conditions of approval, an all-case post-marketing surveillance study was conducted to confirm the real-world safety and efficacy of rituximab in patients of all ages with refractory nephrotic syndrome.

METHODS

All patients scheduled to receive rituximab treatment for refractory nephrotic syndrome were eligible to register (registration: August 29, 2014 through April 15, 2016); the planned observation period was 2 years from the initiation of rituximab treatment (intravenous infusion, 375 mg/m² once weekly for four doses). The study was conducted at 227 hospitals throughout Japan. Adverse drug reactions (ADRs) were collected for safety outcomes. The efficacy outcomes were relapse-free period and the degree of growth in pediatric (< 15 years) patients.

RESULTS

In total, 997 (447 pediatric) patients were registered; 981 (445) were included in the safety analysis set; 852 (402) completed the 2-year observation period; and 810 (429) were included in the efficacy analysis set. Refractory nephrotic syndrome had developed in childhood for 85.0% of patients, and 54.6% were aged ≥15 years. ADRs were observed in 527 (53.7%) patients, treatment-related infection/infestation in 235 (24.0%) patients, and infusion reactions in 313 (31.9%) patients. The relapse-free period was 580 days (95% confidence interval, 511-664). There was a significant change in height standard deviation score (pediatric patients; mean change, 0.093; standard deviation, 0.637; P = 0.009).

CONCLUSION

The safety and efficacy of rituximab treatment in patients with refractory nephrotic syndrome were confirmed in the real-world setting.

CLINICAL TRIAL REGISTRATION

UMIN000014997.

Sulfatase 2 Is Associated with Steroid Resistance in Childhood Nephrotic Syndrome

Glucocorticoid (GC) resistance complicates the treatment of ~10-20% of children with nephrotic syndrome (NS), yet the molecular basis for resistance remains unclear. We used RNAseq analysis and in silico algorithm-based approaches on peripheral blood leukocytes from 12 children both at initial NS presentation and after ~7 weeks of GC therapy to identify a 12-gene panel able to differentiate steroid resistant NS (SRNS) from steroid-sensitive NS (SSNS). Among this panel, subsequent validation and analyses of one biologically relevant candidate, sulfatase 2 (SULF2), in up to a total of 66 children, revealed that both SULF2 leukocyte expression and plasma arylsulfatase activity Post/Pre therapy ratios were greater in SSNS vs. SRNS. However, neither plasma SULF2 endosulfatase activity (measured by VEGF binding activity) nor plasma VEGF levels, distinguished SSNS from SRNS, despite VEGF's reported role as a downstream mediator of SULF2's effects in glomeruli. Experimental studies of NS-related injury in both rat glomeruli and cultured podocytes also revealed decreased SULF2 expression, which were partially reversible by GC treatment of podocytes. These findings together suggest that SULF2 levels and activity are associated with GC resistance in NS, and that SULF2 may play a protective role in NS via the modulation of downstream mediators distinct from VEGF.

The Effect of Interleukin-4 and Dexamethasone on RNA-Seq-Based Transcriptomic Profiling of Human Podocytes: A Potential Role in Minimal Change Nephrotic Syndrome

Interleukin-4 (IL-4) expression is implicated in the pathogenesis of nephrotic syndrome (NS). This study aimed to investigate the changes in the transcriptomes of human podocytes induced by IL-4 treatment and to analyze whether these changes could be affected by simultaneous steroid treatment. Three groups of human podocytes were treated with control, IL-4, and IL-4 plus dexamethasone (DEX), respectively. We performed whole-transcriptome sequencing to identify differentially expressed genes (DEGs) between the groups. We investigated relevant biological pathways using Gene Ontology (GO) enrichment analyses. We also attempted to compare and validate the DEGs with the genes listed in PodNet, a literature-based database on mouse podocyte genes. A total of 176 genes were differentially expressed among the three groups. GO analyses showed that pathways related to cytoskeleton organization and cell signaling were significantly enriched. Among them, 24 genes were listed in PodNet, and 12 of them were previously reported to be associated with IL-4-induced changes in human podocytes. Of the 12 genes, the expression levels of BMP4, RARB, and PLCE1 were reversed when podocytes were simultaneously treated with DEX. In conclusion, this study explored changes in the transcriptome profiles of human podocytes treated with IL-4. Few genes were reported in previous studies and were previously validated in experiments with human podocytes. We speculate that IL-4 may exert pathogenic effects on the transcriptome of human podocytes, and a few genes may be involved in the pathogenesis.

CD80 Insights as Therapeutic Target in the Current and Future Treatment Options of Frequent-Relapse Minimal Change Disease

Minimal change disease (MCD) is the most common cause of idiopathic nephrotic syndrome in children, and it is well known for its multifactorial causes which are the manifestation of the disease. Proteinuria is an early consequence of podocyte injury and a typical sign of kidney disease. Steroid-sensitive patients react well with glucocorticoids, but there is a high chance of multiple relapses. CD80, also known as B7-1, is generally expressed on antigen-presenting cells (APCs) in steroid-sensitive MCD patients. Various glomerular disease models associated with proteinuria demonstrated that the detection of CD80 with the increase of urinary CD80 was strongly associated closely with frequent-relapse MCD patients. The role of CD80 in MCD became controversial because one contradicts finding. This review covers the treatment alternatives for MCD with the insight of CD80 as a potential therapeutic target. The promising effectiveness of CD20 (rituximab) antibody and CD80 inhibitor (abatacept) encourages further investigation of CD80 as a therapeutic target in frequent-relapse MCD patients. Therapeutic-based antibody towards CD80 (galiximab) had never been investigated in MCD or any kidney-related disease; hence, the role of CD80 is still undetermined. A new therapeutic approach towards MCD is essential to provide broader effective treatment options besides the general immunosuppressive agents with gruesome adverse effects.

Impact of steroids and steroid-sparing agents on quality of life in children with nephrotic syndrome

BACKGROUND

Steroids and/or steroid-sparing medications are commonly used for nephrotic syndrome treatment; however, the impact of these medications on health-related quality of life over time is not well described.

METHODS

Longitudinal cohort is up to 5 years where children were assessed with baseline and annual Pediatric Quality of Life Inventory questionnaire. A mixed-effects linear regression determined differences in scores among children receiving steroids and/or steroid-sparing agents for at least 30 days compared with those not on medication at 1, 3, 6, and 12 months prior to assessment.

RESULTS

Among 295 children, 64% were male, with a median age of 3.7 (interquartile range [IQR], 2.7, 5.9) years at diagnosis, and comprised 25% Europeans, 40% South Asians, and 8% East/Southeast Asians. Adjusted HRQOL scores were reduced among children taking steroids and steroid-sparing agents among 705 HRQOL measures (median 2 [IQR, 1, 3] per child). Compared to children without medication, steroid and steroid-sparing agent use up to 12 months prior to assessment were associated with an overall HRQOL drop of 3.17 (95% confidence interval [CI], - 5.25, - 1.08) and 3.18 (95% CI, - 5.24, - 1.12), respectively, after adjustment. Functioning domain scores were reduced by 4.41 points (95% CI, - 6.57, - 2.25) in children on steroids, whereas fatigue domain scores were reduced by 5.47 points (95% CI, - 9.28, - 1.67) in children on steroid-sparing agents after adjustment.

CONCLUSIONS

HRQOL is consistently decreased in children receiving steroids and steroid-sparing agents, with differential effects on functioning and fatigue. Counseling families on possible effects of prolonged treatment periods is important in the management of childhood nephrotic syndrome.

Uncovering the mechanism of Astragali Radix against nephrotic syndrome by intergrating lipidomics and network pharmacology

BACKGROUND

Astragali Radix (AR), a common Traditional Chinese Medicine (TCM), is commonly used for treating nephrotic syndrome (NS) in China. At present, the research on the efficacy of AR against NS is relative clearly, but there are fewer researches on the mechanism.

PURPOSE

The aim of this study was to evaluate the potential beneficial effects of AR in an adriamycin-induced nephropathy rat model, as well as investigate the possible mechanisms of action and potential lipid biomarkers.

METHODS

In this work, a rat model of NS was established by two injections of ADR (3.5 + 1 mg/kg) into the tail vein. The potential metabolites and targets involved in the anti-NS effects of AR were predicted by lipidomics coupled with the network pharmacology approach, and the crucial metabolite and protein were further validated by western blotting and ELISA.

RESULTS

The results showed that 22 metabolites such as l-carnitine, LysoPC (20:3), and SM (d18:1/16:0) were associated with renal injury. Moreover, SMPD1, CPT1A and LCAT were predicted as lipids linked targets of AR against NS, whilst glycerophospholipid, sphingolipid and fatty acids metabolism were involved as key pathways of AR against NS. Besides, AR could play a critical role in NS by improving oxidative stress, inhibiting apoptosis and reducing inflammation. Interestingly, our results indicated that key metabolite l-carnitine and target CPT1 were one of the important metabolites and targets for AR to exert anti-NS effects.

CONCLUSION

In summary, this study offered a new understanding of the protection mechanism of AR against NS by network pharmacology and lipidomic method.

Nephrotic syndrome-associated hypercoagulopathy is alleviated by both pioglitazone and glucocorticoid which target two different nuclear receptors

BACKGROUND

Thrombosis is a potentially life-threatening nephrotic syndrome (NS) complication. We have previously demonstrated that hypercoagulopathy is proportional to NS severity in rat models and that pioglitazone (Pio) reduces proteinuria both independently and in combination with methylprednisolone (MP), a glucocorticoid (GC). However, the effect of these treatments on NS-associated hypercoagulopathy remains unknown. We thus sought to determine the ability of Pio and GC to alleviate NS-associated hypercoagulopathy.

METHODS

Puromycin aminonucleoside-induced rat NS was treated with sham, Low- or High-dose MP, Pio, or combination (Pio + Low-MP) and plasma was collected at day 11. Plasma samples were collected from children with steroid-sensitive NS (SSNS) and steroid-resistant NS (SRNS) upon presentation and after 7 weeks of GC therapy. Plasma endogenous thrombin potential (ETP), antithrombin (AT) activity, and albumin (Alb) were measured using thrombin generation, amidolytic, and colorimetric assays, respectively.

RESULTS

In a rat model of NS, both High-MP and Pio improved proteinuria and corrected hypoalbuminemia, ETP and AT activity (p < .05). Proteinuria (p = .005) and hypoalbuminemia (p < .001) were correlated with ETP. In childhood NS, while ETP was not different at presentation, GC therapy improved proteinuria, hypoalbuminemia, and ETP in children with SSNS (p < .001) but not SRNS (p = .330).

CONCLUSIONS

Both Pio and GC diminish proteinuria and significantly alleviate hypercoagulopathy. Both Pio and MP improved hypercoagulopathy in rats, and successful GC therapy (SSNS) also improved hypercoagulopathy in childhood NS. These data suggest that even a partial reduction in proteinuria may reduce NS-associated thrombotic risk.

A dual efficacy-implementation trial of a novel mobile application for childhood nephrotic syndrome management: the UrApp for childhood nephrotic syndrome management pilot study protocol (UrApp pilot study)

Background

Idiopathic nephrotic syndrome has a relapsing-remitting course in the majority of pediatric patients, demanding vigilant monitoring and self-management. A novel, expert-designed, user-informed mobile application (app), UrApp©, was created to support management tasks, including home urine protein monitoring.

Methods

The UrApp Pilot Study (ClinicalTrials.gov, NCT04075656) is a randomized trial comparing UrApp-supported nephrotic syndrome management with standard-of-care with parallel process evaluation of the intervention delivery. Sixty caregivers of children with newly diagnosed, steroid-sensitive nephrotic syndrome will be randomized 1:1 to UrApp-supported care or standard-of-care. Follow-up will be 1 year, with primary outcomes of adherence to urine monitoring and medications assessed at 6 and 12 months. Secondary outcomes at 6 and 12 months include self-efficacy, quality-of-life, hospitalizations and delayed relapse diagnoses. A mixed-methods approach will evaluate UrApp engagement, use retention, features used, user perceptions, and contextual barriers and facilitators of UrApp use. User behavior will be assessed for relationships to the primary and secondary outcomes. A Stakeholder Committee of volunteer trial participants, clinicians, and engineers will examine the trial results and design a pragmatic UrApp-enhanced nephrotic syndrome intervention with potential for wide implementation. The final UrApp intervention will be tested in a user-centered hybrid effectiveness-implementation trial designed with stakeholder input.

Discussion

The UrApp Pilot Study examines the efficacy of a novel app designed specifically for nephrotic syndrome. The protocol involves dual efficacy and process evaluation aims to increase efficiency and incorporates the stakeholders’ perspective in formative assessment to inform intervention redesign and the design of a future user-centered trial.

Trial registration

ClinicalTrials.gov, NCT04075656. Registered on September 2, 2019, https://clinicaltrials.gov/ct2/show/NCT04075656

Cationic nanoemulsions with prolonged retention time as promising carriers for ophthalmic delivery of tacrolimus

Tacrolimus, also known as FK506, is a first-line drug for the topical treatment of immune-mediated inflammatory anterior ocular diseases (IIAODs). However, due to its limited water solubility, hydrophobic nature and relatively high molecular weight, topical application of FK506 features poor bioavailability. Numbers of formulations have been attempted to enhance the erratic bioavailability of FK506 through various techniques. But until now, none of them could satisfy the clinical needs completely. Here, a novel formulation of FK506, FK506-loaded cationic nanoemulsions (FK506 CNE), was developed to prolong the precorneal residence time of FK506, thereby enhancing the bioavailability of FK506 for IIAODs therapy. FK506 CNE was prepared by high-pressure homogenization, and its composition was screened and optimized by single-factor experiments. The FK506 CNE showed spherical morphology with a mean diameter of 178.8 ± 2.7 nm and a zeta potential of +25.6 ± 0.6 mV. Results from in vivo gamma scintigraphy studies proved that the precorneal residence time of FK506 CNE was significantly increased, compared with FK506-loaded neutral nanoemulsions (FK506 NE) and saline. The data of aqueous humor pharmacokinetic study in rabbits showed that the relative bioavailability of FK506 CNE was 1.68-fold and 1.77-fold of FK506 NE and the marketed FK506 eye drops (Talymus®), respectively. Finally, hematoxylin and eosin staining images and in vitro cytotoxicity data confirmed the safety of the FK506 CNE. Taking all these into consideration, we propose that FK506 CNE is a promising topical ophthalmic nanoformulation for the management of IIAODs.

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

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

Mutations in KIRREL1, a slit diaphragm component, cause steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome is a frequent cause of chronic kidney disease almost inevitably progressing to end-stage renal disease. More than 58 monogenic causes of SRNS have been discovered and majority of known steroid-resistant nephrotic syndrome causing genes are predominantly expressed in glomerular podocytes, placing them at the center of disease pathogenesis. Herein, we describe two unrelated families with steroid-resistant nephrotic syndrome with homozygous mutations in the KIRREL1 gene. One mutation showed high frequency in the European population (minor allele frequency 0.0011) and this patient achieved complete remission following treatment, but later progressed to chronic kidney disease. We found that mutant KIRREL1 proteins failed to localize to the podocyte cell membrane, indicating defective trafficking and impaired podocytes function. Thus, the KIRREL1 gene product has an important role in modulating the integrity of the slit diaphragm and maintaining glomerular filtration function.

Metabolomics coupled with integrative pharmacology reveal the protective effect of FangjiHuangqi Decoction against adriamycin-induced rat nephropathy model

With the development of the society, the number of people who got the nephrotic syndrome (NS) is going up roughly. Therefore, finding a better way to treat NS is becoming a major global public health issue. As we all know, traditional Chinese medicine (TCM), especially Fangji Huangqi Decoction (FHD), has a long history and has good curative effects on NS. However, the mechanism of FHD treating NS has not been clearly elucidated. To address this problem, a feasible system was developed by metabolomics and integrative pharmacology approach. To study the mechanisms of Chinese medical formula FHD treating NS based on metabolomics and integrative pharmacology. In this study, a NMR based metabolomics approach coupled with biochemical assay and Western Blot had been employed to study the protective effect of FHD against adriamycin-induced nephropathy using rat model. And we proposed a integrative pharmacology-based method, which combined chemical ingredients database building, target identification and network analysis. These were aimed to decipher the mechanisms of action for the FHD in NS treatment. Multivariate analysis revealed that 13 of 16 perturbed metabolites could be reversed by FHD, and the MetaboAnalyst analysis revealed that the anti-nephrotic syndrome effect of FHD was probably related with regulation of alanine, aspartate and glutamate metabolism, citrate cycle, pyruvate metabolism, cysteine and methionine metabolism and glyoxylate and dicarboxylate metabolism. The integrative pharmacology analysis revealed 93 potential targets for FHD, and suggested that the protective effect of FHD on the nephrotic syndrome was probably related with the regulation of immune, and energy metabolic and fatty acid metabolic. In addition, both the metabolomics and the integrative pharmacology are focus together on the alanine, aspartate and glutamate metabolism pathway. These metabolites changes and the core targets changes, as well as the metabolite-target pathway network provide insights into the mechanisms of FHD treating nephrotic syndrome, and further studies are needed to validate the bioactive compounds responsible for the anti-nephrotic syndrome effect of FHD.

Text Messaging for Disease Monitoring in Childhood Nephrotic Syndrome

Introduction

There is limited information on effective disease monitoring for prompt interventions in childhood nephrotic syndrome. We examined the feasibility and effectiveness of a novel text messaging system (SMS) for disease monitoring in a multicenter, prospective study.

Methods

A total of 127 patients <19 years with incident nephrotic syndrome were enrolled in the ongoing Nephrotic Syndrome Study Network between June 2015 and March 2018. Text messages soliciting home urine protein results, symptoms, and medication adherence were sent to a designated caregiver (n = 116) or adolescent patient (n = 3). Participants responded by texting. Feasibility of SMS was assessed by SMS adoption, retention, and engagement, and concordance between participant-reported results and laboratory/clinician assessments. The number of disease relapses and time-to-remission data captured by SMS were compared with data collected by conventional visits.

Results

A total of 119 of 127 (94%) patients agreed to SMS monitoring. Retention rate was 94%, with a median follow-up of 360 days (interquartile range [IQR] 353-362). Overall engagement was high, with a median response rate of 87% (IQR, 68-97). Concordance between SMS-captured home urine protein results and edema status with same-day in-person study visit was excellent (kappa values 0.88 and 0.92, respectively). SMS detected a total of 108 relapse events compared with 41 events captured by scheduled visits. Median time to remission after enrollment was 22 days as captured by SMS versus 50 days as captured by scheduled visits.

Conclusion

SMS was well accepted by caregivers and adolescent patients and reliably captured nephrotic syndrome disease activity between clinic visits. Additional studies are needed to explore the impact of SMS on disease outcomes.

Association of infections and venous thromboembolism in hospitalized children with nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) results in hypercoagulability and increased risk of infection. Furthermore, infection increases the risk of venous thromboembolism (VTE). Our objective was to determine the prevalence of infection, VTE, and the associated outcomes among a cohort of hospitalized children with NS.

METHODS

All children with NS admitted to 17 pediatric hospitals across North America from 2010 to 2012 were included. Prevalence of infection and VTE was determined. Wilcoxon rank-sum and logistic regression were performed.

RESULTS

Seven-hundred thirty hospitalizations occurred among 370 children with NS. One-hundred forty-eight children (40%) had ≥ 1 infection (211 episodes) and 11 (3%) had VTE. Those with VTE had infection more frequently (p = 0.046) and were younger at NS diagnosis (3.0 vs. 4.0 years; p = 0.008). The most common infectious pathogen identified was Streptococcus pneumoniae. The median hospital length of stay for those with infection [10 vs 5 days (p < 0.0001)] or VTE [22 vs 6 days (p < 0.0001)] was longer than those without either complication. Of those with infection, 13% had an intensive care unit (ICU) stay compared with 3.3% of those without infection. Median ICU stay was 4 days in those with VTE compared to 0 days in those without (p < 0.001). By logistic regression, only the number of ICU days was associated with VTE (OR 1.074, 95% CI 1.013-1.138).

CONCLUSIONS

Hospitalized children with NS have high rates of infection. Presence of VTE was associated with infection. Both were associated with longer hospitalizations and ICU stays.

Nephrotic Syndrome

Nephrotic syndrome is characterized by edema, proteinuria, hypoalbuminemia, and hyperlipidemia. Minimal change disease, the most common cause in childhood, generally responds to corticosteroids, although most patients experience disease relapses. Focal segmental glomerulosclerosis is usually resistant to corticosteroids and carries a significant risk of kidney failure, necessitating renal transplantation. Nephrotic syndrome may also be secondary to gene mutations and systemic diseases such as lupus. Clinical evaluation involves distinguishing primary and secondary causes and monitoring for disease complications, including blood clots and serious infections such as spontaneous bacterial peritonitis. Immunosuppressive medications are used to prevent relapses and treat corticosteroid-resistant disease.

Association of HLA-DQA1 gene polymorphisms with the risk of children primary nephrotic syndrome in Chinese population

BACKGROUND

The association between gene polymorphisms and the risk of primary nephrotic syndrome (PNS) is uncovering recently. This study aims to investigate the relationship between single nucleotide polymorphisms (SNPs) on HLA-DQA1 gene and the risk of PNS.

METHODS

In this study, we genotyped eight single nucleotide polymorphisms (SNPs) in the HLA-DQA1 gene in 501 PNS patients and 532 healthy people in Chinese population. Then we analyzed associations of these SNPs with the clinical features in primary nephrotic syndrome of children in Chinese population.

RESULTS

Significant associations with PNS were found on missense SNP rs1129740 (GG vs AA, odds ratio (OR) = 1.987, 95% confidence interval (CI) = 1.468-2.652, P = 0.00177049) and rs1047992 (AA vs GG, OR = 1.857, 95% CI = 1.325-2.391, P = 1.1073E-10) of the HLA-DQA1 gene.

CONCLUSIONS

This work suggests SNPs of HLA-DQA1 are risk factors for PNS in Chinese population, which implies roles of immune response in the pathogenesis of PNS.

Boronic acid copolymers for direct loading and acid-triggered release of Bis-T-23 in cultured podocytes

We report an acid-reversible linker for triggered release of Bis-T-23, an experimental small molecule drug for kidney disease treatment that restores podocyte morphology during disease. Bis-T-23 contains catechols, which form an acid-reversible, covalent boronate ester bond with boronic acids. We synthesized phenylboronic acid-containing polymers using reversible addition-fragmentation chain transfer polymerization that were able to directly load and solubilize Bis-T-23. Because of the reversibility of the boronic ester bond, drug was released in its native form in a pH-dependent manner. The polymers rapidly trafficked into acidic compartments and did not exhibit cytotoxicity, and polymer-drug conjugates successfully delivered Bis-T-23 into cultured podocytes.

Adrenocorticotropic Hormone for Childhood Nephrotic Syndrome: The ATLANTIS Randomized Trial

BACKGROUND AND OBJECTIVES

There is renewed interest in adrenocorticotropic hormone (ACTH) for the treatment of nephrotic syndrome. We evaluated the efficacy and safety of ACTH in children with frequently relapsing or steroid-dependent nephrotic syndrome in a randomized trial.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Participants aged 2-20 years old with frequently relapsing or steroid-dependent nephrotic syndrome were enrolled from 16 sites in the United States and randomized 1:1 to ACTH (repository corticotropin injection) or no relapse-preventing treatment. ACTH treatment regimen was 80 U/1.73 m2 administered twice weekly for 6 months, followed by 40 U/1.73 m2 administered twice weekly for 6 months. The primary outcome was disease relapse during the first 6 months. Participants in the control group were offered crossover to ACTH treatment if they relapsed within 6 months. Secondary outcomes were relapse after ACTH dose reduction and treatment side effects.

RESULTS

The trial was stopped at a preplanned interim analysis after enrollment of 31 participants because of a lack of discernible treatment efficacy. Fourteen out of 15 (93%) participants in the ACTH arm experienced disease relapse in the first 6 months, with a median time to first relapse of 23 days (interquartile range, 9-32), compared with 15 out of 16 (94%) participants and at a median of 21 days (interquartile range, 14-51) in the control group. There was no difference in the proportion of relapsed patients (odds ratio, 0.93; 95% confidence interval, 0.05 to 16.40; P>0.99) or time to first relapse (hazard ratio, 1.03; 95% confidence interval, 0.50 to 2.15; P=0.93). Thirteen out of 16 participants in the control group crossed over to ACTH treatment. Three out of 28 participants completed 12 months of ACTH treatment; the others exited the trial because of frequent relapses or side effects. There were no disease relapses after ACTH dose reduction among the three participants. Most side effects were mild and similar to side effects of corticosteroids.

CONCLUSIONS

ACTH at 80 U/1.73 m2 administered twice weekly was ineffective at preventing disease relapses in pediatric nephrotic syndrome.

Rituximab modulates T- and B-lymphocyte subsets and urinary CD80 excretion in patients with steroid-dependent nephrotic syndrome

BACKGROUND

Rituximab, a monoclonal antibody targeting B lymphocytes, effectively sustains remission in steroid-dependent nephrotic syndrome (SDNS). We studied its effects on lymphocyte subsets and urinary CD80 excretion (uCD80) in patients with SDNS.

METHODS

Blood and urine samples were collected from 18 SDNS patients before rituximab, and after 1 month and 1 year or at first relapse. T and B lymphocytes and uCD80 were determined by flow cytometry and ELISA, respectively.

RESULTS

Treatment was associated with reduction in counts of Th17, Th2, and memory T cells, and increased T-regulatory (Treg) cells. The Th17/Treg ratio declined from baseline (median 0.6) to 1 month (0.2, P = 0.006) and increased during relapse (0.3, P = 0.016). Ratios of Th1/Th2 cells at baseline, 1 month after rituximab, and during relapse were 7.7, 14.0 (P = 0.0102), and 8.7, respectively. uCD80 decreased 1 month following rituximab (45.5 vs. 23.0 ng/g creatinine; P = 0.0039). B lymphocytes recovered earlier in relapsers (60.0 vs.183.0 days; P < 0.001). Memory B cells were higher during relapse than remission (29.7 vs.18.0 cells/µL; P = 0.029).

CONCLUSION

Rituximab-induced sustained remission and B-cell depletion was associated with reduced numbers of Th17 and Th2 lymphocytes, and increased Treg cells; these changes reversed during relapses. Recovery of B cells and memory B cells predicted the occurrence of a relapse.

Traditional Chinese Medicine for Refractory Nephrotic Syndrome: Strategies and Promising Treatments

Refractory nephrotic syndrome (RNS) is an immune-related kidney disease with poor clinical outcomes. Standard treatments include corticosteroids as the initial therapy and other immunosuppressants as second-line options. A substantial proportion of patients with RNS are resistant to or dependent on immunosuppressive drugs and often experience unremitting edema and proteinuria, cycles of remission and relapse, and/or serious adverse events due to long-term immunosuppression. Traditional Chinese medicine has a long history of treating complicated kidney diseases and holds great potential for providing effective treatments for RNS. This review describes the Chinese medical theories relating to the pathogenesis of RNS and discusses the strategies and treatment options using Chinese herbal medicine. Available preclinical and clinical evidence strongly supports the integration of traditional Chinese medicine and Western medicine for improving the outcome of RNS. Herbal medicine such as Astragalus membranaceus, Stephania tetrandra S. Moore, and Tripterygium wilfordii Hook F can serve as the alternative therapy when patients fail to respond to immunosuppression or as the complementary therapy to improve therapeutic efficacy and reduce side effects of immunosuppressive agents. Wuzhi capsules (Schisandra sphenanthera extract) with tacrolimus and tetrandrine with corticosteroids are two herb-drug combinations that have shown great promise and warrant further studies.

Dyslipidaemia in nephrotic syndrome: mechanisms and treatment

Nephrotic syndrome is a highly prevalent disease that is associated with high morbidity despite notable advances in its treatment. Many of the complications of nephrotic syndrome, including the increased risk of atherosclerosis and thromboembolism, can be linked to dysregulated lipid metabolism and dyslipidaemia. These abnormalities include elevated plasma levels of cholesterol, triglycerides and the apolipoprotein B-containing lipoproteins VLDL and IDL; decreased lipoprotein lipase activity in the endothelium, muscle and adipose tissues; decreased hepatic lipase activity; and increased levels of the enzyme PCSK9. In addition, there is an increase in the plasma levels of immature HDL particles and reduced cholesterol efflux. Studies from the past few years have markedly improved our understanding of the molecular pathogenesis of nephrotic syndrome-associated dyslipidaemia, and also heightened our awareness of the associated exacerbated risks of cardiovascular complications, progressive kidney disease and thromboembolism. Despite the absence of clear guidelines regarding treatment, various strategies are being increasingly utilized, including statins, bile acid sequestrants, fibrates, nicotinic acid and ezetimibe, as well as lipid apheresis, which seem to also induce partial or complete clinical remission of nephrotic syndrome in a substantial percentage of patients. Future potential treatments will likely also include inhibition of PCSK9 using recently-developed anti-PCSK9 monoclonal antibodies and small inhibitory RNAs, as well as targeting newly identified molecular regulators of lipid metabolism that are dysregulated in nephrotic syndrome.

Fatty Acids in Nephrotic Syndrome and Chronic Kidney Disease

The role of fatty acids (FAs) in inflammation and in the related chronic diseases has been demonstrated. However, there is a lack of consistent and agreed knowledge about the role of FA profile and renal physiology and pathology, most articles focusing on the effect of polyunsaturated FAs supplementation, without considering the impact of basal FA metabolism on the efficacy of the supplementation. Here, we have summarized the specific literature concerning the assessment of circulating FA in 2 renal diseases, namely nephrotic syndrome and chronic kidney disease, also under hemodialytic treatment, and have received the most significant contributions in the last years. The effects of changes of FA profile and metabolism and the possible involvement of polyunsaturated FA metabolites in raising and modulating inflammation are discussed.

Thrombin-Induced Podocyte Injury Is Protease-Activated Receptor Dependent

Nephrotic syndrome is characterized by massive proteinuria and injury of specialized glomerular epithelial cells called podocytes. Studies have shown that, whereas low-concentration thrombin may be cytoprotective, higher thrombin concentrations may contribute to podocyte injury. We and others have demonstrated that ex vivo plasma thrombin generation is enhanced during nephrosis, suggesting that thrombin may contribute to nephrotic progression. Moreover, nonspecific thrombin inhibition has been shown to decrease proteinuria in nephrotic animal models. We thus hypothesized that thrombin contributes to podocyte injury in a protease-activated receptor-specific manner during nephrosis. Here, we show that specific inhibition of thrombin with hirudin reduced proteinuria in two rat nephrosis models, and thrombin colocalized with a podocyte-specific marker in rat glomeruli. Furthermore, flow cytometry immunophenotyping revealed that rat podocytes express the protease-activated receptor family of coagulation receptors in vivo High-concentration thrombin directly injured conditionally immortalized human and rat podocytes. Using receptor-blocking antibodies and activation peptides, we determined that thrombin-mediated injury depended upon interactions between protease-activated receptor 3 and protease-activated receptor 4 in human podocytes, and between protease-activated receptor 1 and protease-activated receptor 4 in rat podocytes. Proximity ligation and coimmunoprecipitation assays confirmed thrombin-dependent interactions between human protease-activated receptor 3 and protease-activated receptor 4, and between rat protease-activated receptor 1 and protease-activated receptor 4 in cultured podocytes. Collectively, these data implicate thrombinuria as a contributor to podocyte injury during nephrosis, and suggest that thrombin and/or podocyte-expressed thrombin receptors may be novel therapeutic targets for nephrotic syndrome.

Glucocorticoid therapy regulates podocyte motility by inhibition of Rac1

Nephrotic syndrome (NS) occurs when the glomerular filtration barrier becomes excessively permeable leading to massive proteinuria. In childhood NS, immune system dysregulation has been implicated and increasing evidence points to the central role of podocytes in the pathogenesis. Children with NS are typically treated with an empiric course of glucocorticoid (Gc) therapy; a class of steroids that are activating ligands for the glucocorticoid receptor (GR) transcription factor. Although Gc-therapy has been the cornerstone of NS management for decades, the mechanism of action, and target cell, remain poorly understood. We tested the hypothesis that Gc acts directly on the podocyte to produce clinically useful effects without involvement of the immune system. In human podocytes, we demonstrated that the basic GR-signalling mechanism is intact and that Gc induced an increase in podocyte barrier function. Defining the GR-cistrome identified Gc regulation of motility genes. These findings were functionally validated with live-cell imaging. We demonstrated that treatment with Gc reduced the activity of the pro-migratory small GTPase regulator Rac1. Furthermore, Rac1 inhibition had a direct, protective effect on podocyte barrier function. Our studies reveal a new mechanism for Gc action directly on the podocyte, with translational relevance to designing new selective synthetic Gc molecules.

Acquired Resistance to Corticotropin Therapy in Nephrotic Syndrome: Role of De Novo Neutralizing Antibody

There is increasing evidence supporting the use of corticotropin as an alternative treatment of refractory proteinuric glomerulopathies. The efficacy of short-acting corticotropin, however, remains unknown and was tested here in an adolescent with steroid-dependent nephrotic syndrome caused by minimal change disease. After developing Cushing syndrome and recently being afflicted with severe cellulitis, the patient was weaned off all immunosuppressants, including corticosteroids. This resulted in a relapse of generalized anasarca, associated with massive proteinuria and hypoalbuminemia. Subsequently, mono-therapy with short-acting animal-derived natural corticotropin was initiated and resulted in a rapid response, marked by substantial diuresis, reduction in body weight, and partial remission of proteinuria. Ten days later, the patient developed mild skin rash and subcutaneous nodules at injection sites. A relapse followed despite doubling the dose of corticotropin, consistent with delayed-onset resistance to treatment. Immunoblot-based antibody assay revealed de novo formation of antibodies in the patient's serum that were reactive to the natural corticotropin. In cultured melanoma cells known to express abundant melanocortin receptors, addition of the patient's serum strikingly mitigated dendritogenesis and cell signaling triggered by natural corticotropin, denoting neutralizing properties of the newly formed antibodies. Collectively, short-acting natural corticotropin seems effective in steroid-dependent nephrotic syndrome. De novo formation of neutralizing antibodies is likely responsible for acquired resistance to corticotropin therapy. The proof of concept protocols established in this study to examine the anticorticotropin neutralizing antibodies may aid in determining the cause of resistance to corticotropin therapy in future studies.

The role of novel biomarkers in childhood idiopathic nephrotic syndrome: a narrative review of published evidence

Two histological subtypes of idiopathic nephrotic syndrome are commonly recognized in children, namely minimal change nephropathy and focal segmental glomerulosclerosis. Children with minimal change nephropathy (the majority of whom are steroid-sensitive) and focal segmental glomerulosclerosis (the majority of whom are steroid-resistant) require early identification in order to ensure appropriate therapeutic intervention and better outcome. Although renal biopsy and histology remain the ideal diagnostic steps to identify these histological subtypes, reports indicate that serum and urinary biomarkers are now being utilized in the investigation of childhood idiopathic nephrotic syndrome. This paper aims to review the diagnostic and prognostic utility of novel biomarkers in childhood idiopathic nephrotic syndrome and to highlight their role in differentiating steroid-sensitive nephrotic syndrome (SRNS) from steroid-resistant nephrotic syndrome (SSNS). Using the terms “idiopathic nephrotic syndrome,” “children,” and “biomarkers” the PubMed database was searched for relevant studies related to the topic. Biomarkers such as adiponectin, neopterin, β2-microglobulin, and N-acetyl-β-D glucosaminidase were reported as diagnostic markers. In addition to neopterin and N-acetyl-β-D glucosaminidase, urine vitamin D-binding protein and α1β-glycoprotein were shown to differentiate SRNS from SSNS while N-acetyl-β-D glucosaminidase and β2-microglobulin could predict steroid responsiveness and renal outcome in SRNS. Although progress has been made in demonstrating the diagnostic and prognostic utility of these biomarkers, their limited availability in most laboratories has precluded a complete paradigm shift from the conventional renal biopsy. Nevertheless, further longitudinal studies are required to establish their usefulness as noninvasive predictors of disease response to immunosuppressive therapy.

Rituximab in children with steroid-dependent nephrotic syndrome: experience of a tertiary center and review of the literature

OBJECTIVES

Rituximab (RTX) is a new treatment option in children with difficult-to-treat steroid-dependent nephrotic syndrome (SDNS). We evaluated the experience of our tertiary center and reviewed the current literature.

METHODS

This is a retrospective single-center study evaluating the efficacy and safety of RTX in children with difficult-to-treat SDNS. Age at diagnosis, type and duration of immunosuppression, age at administration, dose of RTX, possible adverse events, number of relapses, duration of remission, and B-cell count after administration of RTX were analyzed.

RESULTS

Nine children with a median age at diagnosis of nephrotic syndrome of 4.75 (range 1.33-11.33) years and a median age at administration of RTX of 16.08 (range 3.33-19.25) years were included. Before administration of RTX they had a median number of relapses per year of 1.70 (range 0.82-4.80). At last follow-up (median 2.75 years, range 0.58-3.92), a reduction in the number of relapses per year to 0.26 (range 0-2.18) was noted, despite cessation or lowering the dose of immunosuppressive therapy. Four patients achieved complete remission after the first administration of RTX, four more patients after subsequent doses of RTX. No severe adverse events were noted.

CONCLUSION

RTX was an effective and safe therapeutic option in our cohort of children with difficult-to-treat SDNS, resulting in a significant reduction of yearly relapses in the absence of severe adverse events and facilitating the reduction of other immunosuppressive medication.

Setting New Directions for Research in Childhood Nephrotic Syndrome: Results From a National Workshop

Background:

We report on the proceedings of a national workshop held in Canada with the aims to identify priorities for research in childhood nephrotic syndrome and to develop a national strategy to address these priorities.

Methods:

A diverse group of participants attended the meeting, including patients, family members, researchers, and health care providers. We used small group discussions to explore priorities as perceived by patients and families and by health care providers and researchers.

Results:

Research evaluating glucocorticoid minimization or glucocorticoid-sparing regimens was a consistent theme in the patient and family discussion group. Families also indicated the need for precise prognostic information at diagnosis, more information to help them choose the best available therapy, and more resources for disease management. Health care providers emphasized the importance of better disease characterization including genotyping and phenotyping patients, better understanding the pathogenesis, and the need of providing targeted therapy and precise prognostic information.

Conclusions:

These priorities will inform the development and future directions of the Canadian Childhood Nephrotic Syndrome (CHILDNEPH) project, a national research initiative to improve care and outcomes of patients with childhood onset nephrotic syndrome.

Markers of disease and steroid responsiveness in paediatric idiopathic nephrotic syndrome: Whole-transcriptome sequencing of peripheral blood mononuclear cells

Objective

To identify markers of disease and steroid responsiveness in paediatric idiopathic nephrotic syndrome.

Methods

Whole-transcriptome sequencing was performed of peripheral blood mononuclear cells (PBMCs) from patients with NS. Differentially expressed genes (DEGs) were identified in patients with active NS vs those in remission, and those with steroid-sensitive NS (SSNS) vs steroid-resistant NS (SRNS).

Results

A total of 1065 DEGs were identified in patients with NS (n = 10) vs those in remission (n = 9). These DEGs correlated with cytokine and/or immune system signalling and the extracellular matrix. Comparisons between SSNS (n = 6) and SRNS (n = 4) identified 1890 DEGs. These markers of steroid responsiveness were enriched with genes related to the cell cycle, targets of microRNAs, and genes related to cytokines.

Conclusions

Meaningful DEGs were identified. Additional studies with larger numbers of patients will provide more comprehensive data.