The Treatment of Primary IgA Nephropathy: Change, Change, Change

Real-world assessment of sparsentan's drug safety framework

BACKGROUND

Sparsentan has been approved for reducing proteinuria in adult patients with primary IgA nephropathy (IgAN) at risk of rapid disease progression, yet comprehensive studies evaluating its drug safety framework are lacking.

METHODS

Adverse event (AE) reports following the market release of sparsentan were collected from the U.S. Food and Drug Administration AE Reporting System. Disproportionate analysis was used to identify previously unrecognized positive novel signals at both the system organ class and preferred term levels. Additionally, analysis on clinical priorities and subgroup analysis were conducted.

RESULTS

A total of 504 patients with IgAN were included. Two novel system organ classes and 14 novel preferred terms were identified. Hypotension and dizziness were established as moderate clinical priority events. Males had a higher relative risk of nausea, peripheral edema, feeling abnormal, decreased blood pressure, and hypotension, while females were at greater risk for fatigue, pain, increased blood creatinine, dizziness, and somnolence. Among those aged 18-45, the relative risk of experiencing fatigue, pain, and dizziness was higher, individuals aged 45 and older had a higher relative risk of peripheral edema, decreased blood pressure, and hypotension.

CONCLUSIONS

Based on the available AE reporting data, sparsentan exhibits a favorable safety profile, with no high-priority clinical events identified. Our findings offer valuable insights to optimize the use of sparsentan and understand its potential side effects.

Treatment of immunoglobulin A nephropathy: Current perspective and future prospects

Immunoglobulin (Ig) A nephropathy is the most common type of primary glomerulonephritis globally. It typically manifests with microscopic hematuria and a spectrum of proteinuria, although rapidly progressive glomerulonephritis may occur in rare instances. Deposition of IgA in the mesangium seems to be the underlying disease mechanism. Despite current treatment, IgA nephropathy may progress into end-stage renal disease, indicating the necessity for the development of new therapeutic agents. Lifestyle modifications and anti-proteinuric treatment are recommended, and steroids have shown to be beneficial to high risk groups. Nevertheless, other conventional immunosuppressive agents, such as cyclophosphamide and mycophenolate mofetil, may be considered, despite the lack of sufficient evidence to support their efficacy. A considerable proportion of cases remain unresponsive to these treatments, underscoring the need for novel therapeutic approaches. There are several promising immunosuppressive drugs, such as B-cell lineage depleting agents or complement system inhibitors, that are currently undergoing clinical trials. These therapies may be considered for use in selected cases.

The beneficial effect of adding belimumab in severe and refractory IgA nephropathy: a case report

IgA nephropathy (IgAN) is one of the most common primary glomerular diseases worldwide and is the most common cause of chronic kidney disease (CKD) in China. It lacks recommended treatment in refractory IgAN after conventional therapy. Belimumab, a recombinant human IgG-1λ monoclonal antibody that inhibits the B lymphocyte stimulator, is recommended to treat active lupus nephritis. This report presents a case of a child with severe and refractory IgAN who showed kidney response after belimumab addition combined with conventional therapy. The therapy result was accompanied by decreased plasma cells in peripheral blood. It is the first case showing the benefits of adding belimumab to other immunosuppressive regimens.

Moderate to severe chronic arteriolar lesions is an independent risk factor for adverse renal outcomes in IgA nephropathy

BACKGROUND

The impact of chronic arteriolar lesions on the prognosis of IgA nephropathy remains controversial. This study aims to explore the value of chronic arteriolar lesions of varying degrees in predicting the prognosis of IgA nephropathy patients and analyze the associated risk factors that contribute to the formation.

METHODS

A retrospective analysis was conducted on 853 patients diagnosed with IgA nephropathy through renal biopsy at Guangdong Provincial Hospital of Traditional Chinese Medicine between September 1, 2005, and December 31, 2021. Eventually, a total of 574 cases were included in this study. According to the degree of chronic arteriolar lesions, the patients were divided into four groups: no lesion group (n=115), mild lesion group (n=287), moderate lesion group (n=131), and severe lesion group (n=41). Relevant clinical and pathological features and renal outcomes were recorded. Kaplan-Meier analysis, Cox proportional hazards regression, and receiver operating characteristic (ROC) curve analysis were utilized to examine the relationship between different degrees of chronic arteriolar lesions and the prognosis of IgA nephropathy. Additionally, risk factors associated with the development of moderate to severe chronic arteriolar lesions were identified.

RESULTS

Worse clinical and pathological features were observed in the moderate to severe lesions group (P<0.05). Moderate to severe chronic arteriolar lesions (aHR=3.357, 95%CI: 1.018-11.071, P=0.047), creatinine, S1, E1, T2, and C2 were identified as independent risk factors for adverse renal outcomes. Cox multivariate regression analysis on moderate to severe chronic arteriolar lesions demonstrated that creatinine, T2, and C2 were independent risk factors for adverse renal outcomes in patients with moderate to severe chronic arteriolar lesions.

CONCLUSION

Moderate to severe chronic arteriolar lesions independently increases the risk of adverse renal outcomes.

Alternative Complement Pathway Inhibition with Iptacopan in IgA Nephropathy

BACKGROUND

The alternative complement pathway plays a key role in the pathogenesis of IgA nephropathy. Iptacopan specifically binds to factor B and inhibits the alternative pathway.

METHODS

In this phase 3, double-blind, randomized, placebo-controlled trial, we enrolled adults with biopsy-confirmed IgA nephropathy and proteinuria with a 24-hour urinary protein-to-creatinine ratio of 1 or higher (with protein and creatinine both measured in grams) despite optimized supportive therapy. Patients were randomly assigned, in a 1:1 ratio, to receive oral iptacopan (200 mg) or placebo twice daily for 24 months while continuing to receive supportive therapy. The primary objective of this prespecified interim analysis was to assess the efficacy of iptacopan as compared with that of placebo in reducing proteinuria at month 9; the primary end point was the change from baseline in the 24-hour urinary protein-to-creatinine ratio at month 9. The proportion of patients who had a 24-hour urinary protein-to-creatinine ratio of less than 1 at month 9 without receiving rescue or alternative medication or undergoing kidney-replacement therapy (dialysis or transplantation) was a secondary end point. Safety was also assessed. The effect of iptacopan on kidney function will be assessed at the end of the 2-year double-blind treatment period.

RESULTS

The main trial population included 222 patients in the iptacopan group and 221 in the placebo group. The interim efficacy analysis included the first 250 patients who underwent randomization in the main trial population (125 patients in each group) and who remained in the trial until month 9 or discontinued the trial by month 9. Safety was assessed in all the patients in the main trial population. At month 9, the adjusted geometric mean 24-hour urinary protein-to-creatinine ratio was 38.3% (95% confidence interval, 26.0 to 48.6; two-sided P<0.001) lower with iptacopan than with placebo. The reduction in proteinuria was supported by consistent results in secondary end point analyses. There were no unexpected safety findings with iptacopan. The incidence of adverse events that occurred during the treatment period was similar in the two groups; most events were mild to moderate in severity and reversible. No increased risk of infection was observed.

CONCLUSIONS

Among patients with IgA nephropathy, treatment with iptacopan resulted in a significant and clinically meaningful reduction in proteinuria as compared with placebo. (Funded by Novartis; APPLAUSE-IgAN ClinicalTrials.gov number, NCT04578834.).

IPNA clinical practice recommendations for the diagnosis and management of children with IgA nephropathy and IgA vasculitis nephritis

IgA nephropathy and IgA vasculitis with nephritis, albeit rare, represent two relatively frequent glomerular conditions in childhood. Compared to adults, pediatric IgA nephropathy has a more acute presentation, most frequently with synpharyngitic macrohematuria and histologically with more intense inflammation and less intense chronic damage. Management of these conditions is controversial and supported by little high-quality evidence. The paucity of evidence is due to the disease heterogeneity, its inter-ethnic variability, and the difficulty of extrapolating data from adult studies due to the peculiarities of the condition in children. IgA vasculitis with nephritis is a kidney manifestation of a systemic disorder, typical of the pediatric age, in which both the diagnosis of kidney involvement and its management are poorly defined, and an interdisciplinary approach is crucial. Both conditions can have a profound and long-lasting impact on kidney function and the global health of affected children. The International Pediatric Nephrology Association has therefore convened a diverse international group of experts from different disciplines to provide guidance on the recommended management of these conditions in children and to establish common definitions and define priorities for future high-quality, evidence-based collaborative studies for the benefit of children.

Network Pharmacological Analysis of Hydroxychloroquine Intervention in the Treatment of Iga Nephropathy

BACKGROUND

IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis globally and has a high propensity to develop into end-stage renal disease (ESRD). Hydroxychloroquine has been proven to reduce proteinuria in IgAN patients, but the precise mechanism remains unclear. Therefore, network pharmacology was used to investigate the mechanism.

METHODS

PubChem and SwissADME databases were utilized to acquire the structure of hydroxychloroquine. The SwissTargetPrediction, PharmMapper, DrugBank, TargetNet, and BATMAN-TCM databases were then utilized to obtain the targets. The target genes related to IgAN were then gathered from the databases, which included GeneCards, PHARMGKB, DrugBank, OMIM, and DisGeNET. Common targets were obtained by UniProt. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to define the main molecular mechanisms and pathways. Furthermore, a protein-protein interaction (PPI) network was constructed using the STRING tool, and the core targets were obtained by Cytoscape. Finally, molecular docking between the core targets and hydroxychloroquine was performed.

RESULTS

167 common target genes were acquired by overlapping. The core targets were TNF, ALB, IL1B, JUN, FOS, SRC, and MMP9. The GO and KEGG results showed the targets to be related to the production of inflammatory cytokines and chemokines and were engaged in the toll-like receptor (TLR) signaling pathway. At the same time, the molecular docking results showed that the core targets all combined with hydroxychloroquine closely.

CONCLUSION

This study proved that hydroxychloroquine may treat IgAN through the TLR signaling pathway, and the restraint of TNF, TLR, IL1B, and JUN may be essential for the treatment.

What is new in the pathogenesis and treatment of IgA glomerulonephritis

Recently, new findings have been clarified concerning both pathogenesis and treatment of IgA nephritis. The four hits theory has been confirmed but several genetic wide association studies have allowed finding several genes connected with the pathogenesis of the disease. All these new genes apply to each of the four hits. Additionally, new discoveries concerning the microbiota and its connection with immune system and IgA generation have allowed finding out the role of the mucosa in IgA nephropathy pathogenesis. The IgA treatment is also changed included the future possibilities. The treatment of the chronic kidney disease, associated with the nephropathy, is mandatory, since the beginning of the disease. The classical immunosuppressive agents have poor effect. The corticosteroids remain an important cornerstone in any phase of the disease. More effect is related to the treatment of B cells and plasma cells. In particular, in very recent studies have been documented the efficacy of anti B cell-activating factor and anti A proliferation-inducing ligand agents. Most of these studies are to date in phase II/III. Finally, new agents targeting complement are arising. These agents also are still in randomized trials and act principally in hit 4 where the immunocomplexes in the mesangium activate the different pathways of the complement cascade.

Post-transplant IgA nephropathy: a rapidly evolving field of kidney transplant medicine

IgA nephropathy is the commonest pattern of primary glomerular disease in the world, with high rates of progression to kidney failure. As IgA nephropathy commonly causes kidney failure at a young age, kidney transplantation is commonly used to treat kidney failure. However, high rates of recurrent disease in the allograft remain a common management challenge. The prevalence of post-transplant recurrence approaches 15% at ten years post-transplant and is associated with poor allograft function and high rates of allograft loss. Post-transplant IgA nephropathy has also been described de novo in some case series. Treatment of recurrent IgA nephropathy has been challenging but with the rapid growth of new treatments for IgA nephropathy it is likely that many of these treatments will, over time, transition to the treatment of recurrent disease. In this narrative review, our aim is to evaluate post-transplant IgA nephropathy in terms of epidemiology, risk factors, underlying pathophysiology, diagnosis and management strategies.

Emerging perspectives in the management of IgA nephropathy: a comprehensive review

IgA nephropathy (IgAN) is the most prevalent form of primary glomerulonephritis worldwide and a leading cause of chronic kidney disease and renal failure. This disorder is characterized by the deposition of immune complexes containing galactose-deficient forms of IgA and complement C3 in the glomeruli. Until now, disease management relied mainly on optimized supportive care. Systemic corticosteroid therapy is proposed for patients at high risk of disease progression, but the effectiveness and safety of this approach are under debate. A significant proportion of patients do not respond to current therapies and require kidney replacement therapy at a young age, with substantial costs and impact on quality of life. Recently, there have been multiple joint efforts to improve the understanding of IgAN pathophysiology. International collaborations resulted in multiple ongoing clinical trials that are providing new insights toward innovative therapeutic options such as SGLT2 inhibitors, dual endothelin and angiotensin receptor blockers, targeted-release budesonide, B-cell proliferation and differentiation inhibitors, and complement system blockers. Based on this new evidence, revision of the guidelines to manage IgAN is expected to occur in the near future. In addition to the novelty in therapeutic agents, there is also a growing interest in new noninvasive biomarkers for IgAN screening, risk stratification to monitor the course of the disease, and the response to treatment. In this review, we discuss current knowledge on the pathophysiology of IgAN, disease management, and emerging advances in clinical translation of IgAN research.

Off-Label Use of Mycophenolate Mofetil in Immunoglobulin A Nephropathy: A Systematic Review and Meta-Analysis

INTRODUCTION

Mycophenolate mofetil (MMF) is widely used off-label in patients with immunoglobulin A nephropathy (IgAN), although the literature does not consistently agree on its efficacy and safety.

METHODS

We systematically searched PubMed, Embase, CENTRAL, CNKI, VIP, Wanfang Data, and SinoMed from their inception to August 2023. We included randomized controlled trials that enrolled patients of IgAN who received MMF treatment and compared effects with placebo or as an add-on therapy to usual care. Literature screening, risk of bias assessment, and data extraction were independently conducted in duplicate. Fixed-effects or random-effects meta-analyses were performed for pooling data where eligible. The primary outcomes were the composite kidney outcomes of major adverse kidney events (MAKDE) defined as doubling of serum creatinine, end-stage renal disease (ESRD), or death from a kidney disease-related or cardiovascular cause.

RESULTS

Of 13 studies identified, 918 participants (463 [50.4%] treated with MMF) with IgAN were included in the analysis. MMF treatment in IgAN was associated with decreasing the occurrence of MAKDE (relative risk [RR], 0.32; 95% confidence interval [CI], 0.13-0.77), reducing proteinuria (RR, 1.41; 95% CI, 1.22-1.64), and lessening the probability of doubling blood creatinine (RR, 0.32, 95% CI, 0.14-0.72). No significant differences were detected in the incidence of ESRD (RR, 0.87, 95% CI, 0.38-2.03), or progression of chronic kidney disease (RR, 1.01; 95% CI, 0.22-4.57). Patients receiving MMF had a higher risk of infection (RR, 2.20; 95% CI, 1.21-4.00).

CONCLUSION

MMF administration in IgAN indicates promising in decreasing the occurrence of MAKDE, reducing proteinuria level, and lessening the probability of doubling blood creatinine, but also comes with the risk of infection. These findings tend to be introduced to non-Caucasian population. The long-term favorable effects that MMF improved kidney outcomes still need further cross-regional and cross-ethnical verification.

Exploring Novel Adverse Events of Nefecon

Introduction

Nefecon, the first innovative drug approved by both the US Food and Drug Administration (FDA) and European Medicines Agency for IgA nephropathy (IgAN), lacked comprehensive real-world assessments of its adverse events (AEs).

Methods

We leveraged postmarketing data of Nefecon from the US FDA Adverse Event Reporting System (FAERS), employing disproportionate analysis (DPA) to detect positive signals at the system organ class (SOC) and preferred terms (PTs) levels. Duplicate AEs related to budesonide and those previously reported in studies were excluded through the use of the Medical Dictionary of Regulatory Activities (MedDRA). Our analysis encompassed time-to-onset (TTO), Weibull shape parameter (WSP) evaluation, cumulative incidence, clinical prioritization evaluation, and subgroup analysis based on gender and age.

Results

A total of 1515 individuals with IgAN were included. Five positive SOC signals and 23 positive PT signals were identified, including 4 PTs (asthenia, malaise, product dose omission issue, and anxiety) representing novel AEs newly identified in this study. None of the positive PTs were classified as high clinical priority, with only acne, hypertension, swelling face, and weight increased considered as moderate clinical priority events. The median time to TTO was 31 days. All WSP test results indicated an early failure type profile. Lastly, subgroup analysis provided further insights into the relative risk of specific AEs.

Conclusion

Nefecon demonstrates a favorable safety profile, with no high-priority clinical events identified. The identification of novel AEs and subgroup-specific relative high-risk events fills a gap in existing studies and offers valuable insights for early clinical vigilance.

Utilizing complement inhibition in IgA nephropathy

The role of complement in the pathogenesis of IgA nephropathy has been heavily explored over the past 50 years. This has led to the general acceptance that complement plays an important role in the clinical presentation and risk for progression of disease in patients with IgA nephropathy. Herein, we review the evidence for complement activation in IgA nephropathy, focusing on evidence that the lectin and alternate pathways are the main actors. We are entering an era of intense investigation of various inhibitors of complement, which should ultimately be the best indicator of contributions of the lectin, alternate and common complement pathways to disease burden. More importantly, we will see if these efforts result in the discovery of clinically relevant options in managing this important disease.

Therapy of IgA nephropathy: time for a paradigm change

Immunoglobulin A nephropathy (IgAN) often has a poor outcome, with many patients reaching kidney failure within their lifetime. Therefore, the primary goal for the treatment of IgAN should be to reduce nephron loss from the moment of diagnosis. To achieve this, IgAN must be recognized and treated as both a chronic kidney disease and an immunological disease. Agents that have received US Food and Drug Administration and European Medicines Agency approval for the treatment of IgAN include modified-release/targeted-release formulation budesonide (Nefecon) and sparsentan, a selective dual endothelin-A and angiotensin II receptor type 1 antagonist. Other agents, including selective endothelin receptor antagonists, selective or combined APRIL and BAFF antagonists, and a vast array of complement inhibitors are being investigated for the treatment of IgAN. Furthermore, treatment combinations are also being studied, including sodium-glucose cotransporter-2 inhibitors with endothelin receptor antagonists. Due to the complexity of IgAN, combination treatment, rather than a single-agent approach, may provide maximum benefit. With the number of treatments for IgAN likely to increase, combinations allowing safe and effective treatment to halt progression to kidney failure seem within grasp. While trials evaluating combinations are ongoing, more are needed to pave the way for a comprehensive IgAN treatment strategy. Furthermore, an approach to IgAN treatment in which agents are combined early to achieve rapid induction of remission and prevent unnecessary and irreversible nephron loss is required. Following remission, treatments may be adjusted and stripped back as necessary in the maintenance phase with close monitoring. This review discusses the current status of IgAN treatment and explores future strategies to improve outcomes for patients with IgAN.

Circulating Proteins and IgA Nephropathy: A Multiancestry Proteome-Wide Mendelian Randomization Study

Key Points

Background

The therapeutic options for IgA nephropathy are rapidly evolving, but early diagnosis and targeted treatment remain challenging. We aimed to identify circulating plasma proteins associated with IgA nephropathy by proteome-wide Mendelian randomization studies across multiple ancestry populations.

Methods

In this study, we applied Mendelian randomization and colocalization analyses to estimate the putative causal effects of 2615 proteins on IgA nephropathy in Europeans and 235 proteins in East Asians. Following two-stage network Mendelian randomization, multitrait colocalization analysis and protein-altering variant annotation were performed to strengthen the reliability of the results. A protein–protein interaction network was constructed to investigate the interactions between the identified proteins and the targets of existing medications.

Results

Putative causal effects of 184 and 13 protein–disease pairs in European and East Asian ancestries were identified, respectively. Two protein–disease pairs showed shared causal effects across them (CFHR1 and FCRL2). Supported by the evidence from colocalization analysis, potential therapeutic targets were prioritized and four drug-repurposing opportunities were suggested. The protein–protein interaction network further provided strong evidence for existing medications and pathways that are known to be therapeutically important.

Conclusions

Our study identified a number of circulating proteins associated with IgA nephropathy and prioritized several potential drug targets that require further investigation.

Clinical features and prognosis of patients with anti-GBM disease combined with mesangial IgA deposition

Introduction

Anti-GBM diseases with IgA deposition in the mesangial region are rarely described.The factors influencing renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition are unknown.

Methods

We searched the pathological reports of the First Affiliated Hospital of Zhengzhou University from 2015 to 2023 and found that a total of 72 patients with the anti-GBM disease and 25 patients combined with mesangial IgA deposition. We studied the clinical and pathological features, renal prognosis, and the factors affecting renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition.

Results

Their median age was 44 years, and their age distribution was unimodal. The proportion of oliguria or anuria in patients with anti-GBM disease combined with mesangial IgA deposition was significantly lower than that in patients with classic anti-GBM disease (13.04 vs. 42.31%, p=0.030). Their 24-hour urinary protein excretion was significantly higher [median:3.25 vs. 1.12g/24h, Interquartile range(IQR):1.032~3.945 vs. 0.63~1.79g/24h, p=0.020], serum creatinine (SCr) level at the initial diagnosis was lower(median:456.0 vs. 825.5μmol/L, IQR:270.0~702.0 vs. 515.8~1231.2μmol/L, p=0.002), peak SCr level was lower (median: 601.0 vs. 907.2μmol/L, IQR: 376.5~937.0 vs. 607.0~1361.2μmol/L, p=0.007), and their serum complement 3(C3) level was higher(median: 1.275 vs. 1.015g/L, IQR:1.097~1.462 vs. 0.850~1.220g/L, p=0.027). They had better renal outcomes during follow-up (p<0.001). After adjustment for hypertension, oliguria or anuria, and crescents%, IgA deposition in the mesangial region was still an independent protective factor (p=0.003) for ESRD in anti-GBM patients. Hypertension (p=0.026) and SCr levels at initial diagnosis (p=0.004) were risk factors for renal prognosis in patients with anti-GBM disease combined with mesangial IgA deposition.

Discussion

Patients with anti-GBM disease combined with mesangial IgA deposition have less severe renal impairment and better renal prognosis than patients with classic anti-GBM disease.

Does Metabolic Syndrome and Its Components Have Prognostic Significance for Renal and Cardiovascular Outcomes in IgA Nephropathy?

BACKGROUND

Patients with IgA nephropathy (IgAN), a chronic kidney disease (CKD), are significantly more likely to have cardiovascular (CV) mortality and morbidity than the general population. The occurrence of metabolic syndrome (MetS) and metabolic risk factors are independent risk factors for CV disease and renal progression. The purpose of this study was to determine how metabolic characteristics in a homogeneous population of CKD patients relate to prognosis.

METHODS

A total of 145 patients with CKD stages 1-4 diagnosed with IgA nephropathy (92 men and 53 women, aged 54.7 ± 13 years) were examined and monitored for a median of 190 months. All-cause mortality and any CV event, such as stroke, myocardial infarction, revascularization (CV), end-stage renal disease, and renal replacement therapy (renal), have been included in the composite endpoints (CV and renal).

RESULTS

Patients with MetS had significantly more primary endpoint events (23/65 patients vs. 15/60 patients, p < 0.001) compared to the non-MetS group. The MetS group had a statistically significant increase in both primary renal and CV endpoints (18/65 vs. 10/60, p = 0.001), and in CV endpoint events (7/65 vs. 6/60, p = 0.029) among the secondary endpoints (CV and renal separately). Based on Cox regression analysis, the main endpoint independent predictors of survival were dyslipidemia, eGFR, hemoglobin, urine albuminuria, and diabetes mellitus. Independent predictors of secondary renal endpoints were dyslipidemia, hemoglobin, urine albumin, and eGFR. Predictors of secondary cardiovascular endpoints were gender, BMI, and diabetes. When Kaplan-Meier curves were analyzed at the combined endpoints (CV and renal) or each endpoint independently, significant differences were seen between MetS and non-MetS. With more MetS components, the primary endpoint rate increased significantly (MetS comp. 0 vs. MetS comp. 2+, primary endpoints, p = 0.012).

CONCLUSIONS

Our results show that the metabolic profile has a prognostic role not only for renal endpoints but also for CV endpoints in IgAN. BMI, hyperuricemia, hypertension, and diabetes have a predictive value for the prognosis of IgA nephropathy.

Comprehensive Analysis of ceRNA Network and Immune Cell Infiltration Pattern of Autophagy-Related Genes in IgA Nephropathy

INTRODUCTION

IgA nephropathy (IgAN) is a prevalent worldwide glomerular disease with a complex pathophysiology that has significant economic implications. Despite the lack of successful research, this study aims to discover the potential competing endogenous RNA (ceRNA) network of autophagy-associated genes in IgAN and examine their correlation with immune cell infiltration.

METHODS

Autophagy-related hub genes were discovered by assessing the GSE116626 dataset and constructing a protein-protein interaction network. Nephroseq v5 analysis engine was used to analyze correlations between hub genes and proteinuria, glomerular filtration rate (GFR), and serum creatinine levels. Then, a ceRNA network construction and the CIBERSORT tool for immune cell infiltration analysis were also performed. Additionally, the differentially expressed autophagy-related genes were used to predict potential targeted medications for IgAN.

RESULTS

Overall, 1,396 differentially expressed genes were identified in IgAN along with 25 autophagy-related differentially expressed messenger RNAs. Enrichment analysis revealed significant involvement of autophagy and apoptosis in biological processes. Next, we evaluated the top hub nodes based on their highest degrees. The ability of IgAN discrimination was confirmed in the GSE35487 and GSE37460 datasets by validating the five hub genes: SIRT1, FOS, CCL2, CDKN1A, and MYC. In the Nephroseq v5 analysis engine, the clinical correlation of the five hub genes was confirmed. Furthermore, the ceRNA network identified 18 circular RNAs and 2 microRNAs associated with hub autophagy-related genes in IgAN. Our investigation identified hsa-miR-32-3p and hsa-let-7i-5p as having elevated expression levels and substantial diagnostic value. Finally, four distinctively infiltrated immune cells were found to be associated with the hub autophagy-related genes, and 67 drugs were identified as potential therapeutic options for IgAN.

CONCLUSION

This study sheds light on a novel ceRNA regulatory network mechanism associated with autophagy in IgAN development.

Histological reappraisal of IgA nephropathy: the role of glomerular pattern of injury and mesangial complement deposition

BACKGROUND

There is a clear need to refine the histological assessment in IgA Nephropathy (IgAN). We sought to investigate the clinical significance of the light microscopy (LM) pattern of glomerular injury and of the intensity of mesangial C3 staining in IgAN.

METHODS

We conducted a retrospective, observational study that included all patients with biopsy-proven primary IgAN that had at least 12 months of follow-up. The LM pattern of glomerular injury was reevaluated based on a modified HAAS classification. Mesangial C3 deposition by immunofluorescence (IF) staining was scored semi-quantitatively. The study primary composite endpoint was defined as doubling of serum creatinine or ESRD (dialysis, renal transplant or eGFR < 15 ml/min). The secondary study endpoint was eGFR decline per year.

RESULTS

This cohort included 214 patients with IgAN (mean age, 41.4 ± 12.6 years), with a mean eGFR and median 24-h proteinuria of 55.2 ± 31.5 ml/min/1.73m2 and 1.5 g/day (IQR:0.8-3.25), respectively. The most frequent LM pattern was the mesangioproliferative (37.4%), followed by the sclerotic (22.5%) and proliferative/necrotizing patterns (21.4%). Regarding the IF findings, mild-moderate and intense mesangial C3 staining was present in 30.6% and 61.1% of patients, respectively. Those with sclerosing and crescentic patterns had the worst renal survival (5-year renal survival of 48.8% and 42.9%) and the highest rate of eGFR change/year (-2.32 ml/min/y and - 2.16 ml/min/y, respectively) compared to those with other glomerular patterns of injury. In addition, those with intense C3 staining reached the composite endpoint more frequently compared to those without intense C3 staining (35.5% vs. 21.4%, p = 0.04). After multivariate adjustment, patients with crescentic and sclerosing patterns had a 3.6-fold and 2.1-fold higher risk for the composite endpoint compared to those with mesangioproliferative pattern, while an intense mesangial C3 deposition being also associated with a worse renal outcome (HR, 3.33; 95%CI, 1.21-9.2).

CONCLUSIONS

We have shown that the LM pattern of glomerular injury and the intensity of mesangial C3 deposition might stratify more accurately the renal outcome in patients with IgAN.

Post-Transplant Glomerulonephritis: Challenges and Solutions

Glomeruli can be damaged in several conditions after kidney transplantation, with a potential impact on the graft function and survival. Primary glomerulonephritis, a group of glomerular immunological damage that results in variable histological patterns and clinical phenotypes, can occur in kidney transplant recipients as a recurrent or de novo condition. Specific immunologic conditions associated with kidney transplantation, such as acute rejection episodes, can act as an additional trigger after transplantation, impacting the incidence of these glomerulopathies. The post-transplant GN recurrence ranges from 3% to 15%, varying according to the GN subtype and post-transplant time, mainly occurring after 3-5 years of kidney transplantation. Advances in the knowledge of glomerulonephritis pathophysiology have provided new approaches to pre-transplant risk evaluation and post-transplant monitoring. Glomeruli can be affected by several systemic viral infections, such as human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV), severe acute respiratory syndrome coronavirus 2 (SARS-COV-2), cytomegalovirus (CMV), and BK virus. The diagnosis of these infections, as well as the identification of possible complications associated with them, are important to minimize the negative impacts of these conditions on kidney transplant recipients' outcomes.