Long-Term Exposure to Air Pollution and Increased Risk of Membranous Nephropathy in China

Changes in the spectrum of biopsy-proven renal diseases over 11 years: a single-center study in China

BACKGROUND

There have been some shifts in the frequency and distribution of biopsy-proven renal diseases in China over recent years. The aim of the study was to investigate the changing spectrum of renal diseases from the view of kidney biopsy data in a single center of China.

METHODS AND RESULTS

A total of 10,996 cases of native renal biopsies from patients aged ≥15 years old in Huashan Hospital, Fudan University, between 2008 and 2018 were analyzed retrospectively. The results showed that primary glomerular nephropathy (PGN) remained the most common biopsy-proven renal disease (69.42% of total), with IgA nephropathy (IgAN) accounting for 44.40% of PGN, membranous nephropathy (MN) for 28.55%, minimal change disease (MCD) for 13.26% and focal segmental glomerulosclerosis (FSGS) for 8.00%. During the study period, the proportion of MN in PGN appeared an increasing tendency, while that of IgAN and MCD remained stable and that of FSGS showed a decline. Secondary glomerular nephropathy (SGN) constituted 21.54% of total cases, among which the leading two diseases were lupus nephritis (LN) and Henoch-Schonlein purpura nephritis (HSN) which accounted for 41.08% and 19.11% respectively.

CONCLUSIONS

The 11-year retrospective study revealed that PGN was the predominant histologic diagnosis among patients undergoing renal biopsy and the most frequent type of PGN remained to be IgAN, followed by MN which increased dramatically.

Efficacy and safety of Mahuang Fuzi and Shenzhuo Decoction for treatment of primary membranous nephropathy: a multicenter prospective trial

BACKGROUND

This study aims to undertake a comprehensive assessment of the effectiveness and safety profile of Mahuang Fuzi and Shenzhuo Decoction (MFSD) in the management of primary membranous nephropathy (PMN), within the context of a prospective clinical investigation.

METHODS

A multicenter, open-label clinical trial was executed on patients diagnosed with PMN. These individuals were subjected to MFSD therapy for a duration of at least 24 months, with primary outcome of clinical remission rates. The Cox regression analysis was employed to discern the pertinent risk factors exerting influence on the efficacy of MFSD treatment, with scrupulous monitoring of any adverse events.

RESULTS

The study comprised 198 participants in total. Following 24 months of treatment, the remission rate was 58.6% (116/198). Among the subgroup of 130 participants subjected to a 36-month follow-up, the remission rate reached 70% (91/130). Subgroup analysis revealed that neither a history of immunosuppressive therapy (HIST) nor an age threshold of ≥60 years exhibited a statistically significant impact on the remission rate at the 24-month mark (p > .05). Multivariate Cox regression analyses elucidated HIST, nephrotic syndrome, or mass proteinuria, and a high-risk classification as noteworthy risk factors in the context of MFSD treatment. Remarkably, no fatalities resulting from side effects were documented throughout the study's duration.

CONCLUSIONS

This trial establishes the efficacy of MFSD as a treatment modality for membranous nephropathy. MFSD demonstrates a favorable side effect profile, and remission rates are consistent across patients, irrespective of HIST and age categories.

Metformin attenuates PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway in proximal renal tubular epithelial cells

The harmful effects of PM2.5 on human health, including an increased risk of chronic kidney disease (CKD), have raised a lot of attention, but the underlying mechanisms are unclear. We used the Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) to simulate the inhalation of PM2.5 in the real environment and established an animal model by exposing C57BL/6 mice to filtered air (FA) and Particulate Matter (PM2.5) for 8 weeks. PM2.5 impaired the renal function of the mice, and the renal tubules underwent destructive changes. Analysis of NHANES data showed a correlation between reduced kidney function and higher blood levels of PM2.5 components, polychlorinated biphenyls (PCBs) and dioxins, which are Aryl hydrocarbon Receptor (AhR) ligands. PM2.5 exposure induced higher levels of AhR and CYP1A1 and oxidative stress as evidenced by the higher levels of ROS, MDA, and GSSG in kidneys of mice. PM2.5 exposure led to AhR overexpression and nuclear translocation in proximal renal tubular epithelial cells. Inhibition of AhR reduced CYP1A1 expression and PM2.5-increased levels of ROS, MDA and GSSG. Our study suggested metformin can mitigate PM2.5-induced oxidative stress by inhibiting the AhR/CYP1A1 pathway. These findings illuminated the role of AhR/CYP1A1 pathway in PM2.5-induced kidney injury and the protective effect of metformin on PM2.5-induced cellular damage, offering new insights for air pollution-related renal diseases.

B cell dysregulation and depletion therapy in primary membranous nephropathy: Prospects and potential challenges

B cells are crucial to the humoral immune response, originating in the bone marrow and maturing in the spleen and lymph nodes. They primarily function to protect against a wide range of infections through the secretion of antibodies. The role of B cells in primary membranous nephropathy (PMN) has gained significant attention, especially following the discovery of various autoantibodies that target podocyte antigens and the observed positive outcomes from B cell depletion therapy. Increasing evidence points to the presence of abnormal B cell subsets and functions in MN. B cells have varied roles during the different stages of disease onset, progression, and relapse. Initially, B cells facilitate self-antigen presentation, activate effector T cells, and initiate cellular immunity. Subsequently, the disruption of both central and peripheral immune tolerance results in the emergence of autoreactive B cells, with strong germinal center responses as a major source of MN autoantibodies. Additionally, critical B cell subsets, including Bregs, memory B cells, and plasma cells, play roles in the immune dysregulation observed in MN, assisting in predicting disease recurrence and guiding management strategies for MN. This review offers a detailed overview of research advancements on B cells and elucidates their pathological roles in MN.

Animal models of membranous nephropathy: more choices and higher similarity

Membranous nephropathy (MN) is an antibody-mediated autoimmune glomerular disease in which PLA2R1 is the main autoantibody. It has become the most common cause of adult nephrotic syndrome, and about one-third of patients can progress to end-stage kidney disease, but its pathogenesis is still unclear. Animal models can be used as suitable tools to study the pathogenesis and treatment of MN. The previous Heymann nephritis rat model and C-BSA animal model are widely used to study the pathogenesis of MN. However, the lack of target antigen expression in podocytes of model animals (especially rodents) restricts the application. In recent years, researchers constructed animal models of antigen-specific MN, such as THSD7A, PLA2R1, which more truly simulate the pathogenesis and pathological features of MN and provide more choices for the follow-up researchers. When selecting these MN models, we need to consider many aspects, including cost, difficulty of model preparation, labor force, and whether the final model can answer the research questions. This review is to comprehensively evaluate the mechanism, advantages and disadvantages and feasibility of existing animal models, and provide new reference for the pathogenesis and treatment of MN.

The outcomes of primary membranous nephropathy treated with cyclophosphamide are superior to calcineurin inhibitors in patients with renal vascular lesions: A multi-center retrospective cohort study

BACKGROUND

The difference of the outcomes of primary membranous nephropathy (PMN) with renal vascular lesions treated with cyclophosphamide (CTX) compared to calcineurin inhibitors (CNIs) remains undetermined.

METHODS

872 patients with PMN finished CNIs or CTX-based therapy between 2003 and 2018 from three centers in China were followed up at most to 120 months. A propensity-score matched (PSM) method was used to analyze the difference of outcomes between those receiving CTX- and CNIs-based therapy. Primary endpoints were defined as a composite of a 50 % decline in eGFR, progression to end-stage renal disease, or all-cause mortality. Dual immunohistochemical staining of CD31 and α-smooth muscle action were applied to detect pathological vascular lesions.

RESULTS

A total of 761 patients were included in the study. After PSM, no significant difference of proteinuria complete remission rate was found between 126 paired patients (HR, 1.32; 95 % CI, 0.95 to 1.83; p = 0.10). However, CTX-based therapy was associated with significantly better renal survival compared to CNI-based therapy. (median, 156 months vs. 108 months; hazard ratio [HR], 0.31; 95 % confidence interval [CI]0.16 to 0.61; p = 0.001). Subgroup analyses showed that CTX-based therapy was superior to CNIs-based therapy among patients with hyalinosis damage (HR, 0.16; 95 % CI 0.05 to 0.50; p = 0.002;), arteriosclerosis (HR, 0.31; 95 % CI 0.15 to 0.62; p = 0.001), or hypertension (HR, 0.21; 95 % CI 0.08 to 0.53; p = 0.001).

CONCLUSIONS

CTX-based therapy exhibited a significantly improved composite endpoint of PMN patients with vascular lesions compared to CNIs-based regime.

Exploring PLA2R and HLA in membranous nephropathy: A narrative review of pathogenic mechanisms and emerging therapeutic potentials

Membranous Nephropathy (MN), a non-inflammatory autoimmune glomerulopathy, is a prominent cause of nephrotic syndrome, predominantly affecting Caucasian adults. It is characterized by significant thickening of the glomerular basement membrane, a direct result of immune complex deposition. Fundamental to its pathogenesis are the Phospholipase A2 receptor (PLA2R) and Human Leukocyte Antigens (HLA), which play crucial and interconnected roles. Specifically, PLA2R serves as the primary antigen, while HLA molecules facilitate MN-specific immune responses, thereby providing key insights into the disease's etiology. This study critically examines the roles of PLA2R and HLA in MN, with a particular focus on the antigenic epitopes of PLA2R. Given MN's complex nature, personalized therapeutic interventions are essential. Accordingly, targeting immunogenic epitopes has emerged as a transformative approach, aimed at modulating specific immune responses without disrupting overall immune function. Numerous studies and clinical trials have been advancing the application of these epitopes in therapeutic strategies. Nevertheless, challenges such as identifying effective epitopes, enhancing epitope-specific responses, and optimizing therapeutic dosing remain. This narrative review addresses these challenges in depth, offering a comprehensive insight into the pathology and emerging treatment strategies for MN.

Oral bacteriome and mycobiome of patients with idiopathic membranous nephropathy with different tongue coatings treated with a Chinese herbal formula

ETHNOPHARMACOLOGICAL RELEVANCE

Moshen Fuyuan Formula (MSFY) is one of the representative Chinese medicine compound for Idiopathic membranous nephropathy (IMN), that originate from Fang Ji Huang Qi decoction in the Han dynasty. IMN is usually accompanied by different tongue coatings in traditional Chinese medicine (TCM), and tongue microorganisms are important factors affecting the formation of the tongue coating. Recently, oral microbiomes, including bacteria and fungi, have been identified as pivotal factors that contribute to disease development. However, the regulation of oral microbiomes by MSFY has not been defined.

AIM OF THE STUDY

In this work, we explore the characteristics of oral bacteria and fungi in IMN patients with different tongue coatings, and clarify the therapeutic effect of MSFY based on oral microbiome.

MATERIALS AND METHODS

We enrolled 24 patients with IMN, including 11 with white tongue (IMN-W) and 13 with yellow tongue (IMN-Y), and recruited an additional 10 healthy individuals. Patients with IMN were treated with the MSFY. The oral bacteriome and fungi before and after treatment were detected using full-length 16S rRNA and internal transcribed spacer gene sequencing.

RESULTS

The therapeutic effect of MSFY on patients with yellow tongue coating was more significant than that on patients with white tongue coating. In terms of oral bacteriome, Campylobacter bacteria were enriched in patients with yellow tongue and could be a promising biomarker for yellow coating. Enrichment of Veillonella parvula_A may partially account for the therapeutic effect of MSFY. As for oral fungi, Malassezia globosa was enhanced in patients with IMN-W and reduced in patients with IMN-Y. Notably, it was reduced by MSFY. We also found that mycobiome-bacteriome interactions were highly complex and dynamic in patients with IMN.

CONCLUSION

The regulation of the dynamic balance between oral fungi and bacteria by MSFY contributes to the treatment of IMN. This study determined the oral bacteriome and mycobiome of patients with IMN with different tongue coatings before and after MSFY treatment, which aids in promoting personalized treatment in clinical TCM and provides direction for investigating the mechanism of Chinese herbal medicines.

Bibliometric and visual analysis of membranous nephropathy literature from 2010 to 2023

Background

Membranous glomerulonephritis, also known as membranous nephropathy (MN), is a common cause of nephrotic syndrome in adults. Despite extensive research on MN, bibliometric studies on the subject are scarce. Therefore, this study aimed to provide a visual analysis of global trends in membranous nephropathy research over the past 13 years.

Methods

This study conducted a bibliometric and visual analysis of global trends in MN research from 2010 to 2023. Articles related to MN were retrieved from the Web of Science Core Collection (WoSCC) database. Tools such as CiteSpace and VOSviewer were utilized to analyze publications, countries, institutions, authors, publishing journals, co-cited references, and keywords to identify the current state and future trends in MN research.

Results

The analysis encompassed 1,624 publications, showing an annual increase from 2010 to 2023. The People's Republic of China emerged as the most active country in this field, while France's Sorbonne Universite and Institut National de la Sante et de la Recherche Medicale (Inserm) led in publication volume among academic institutions. Debiec Hanna stood out as the most prolific author. BMC Nephrology had the highest number of publications, making it the most favored journal in the field. The article with the greatest co-citation intensity was "Primary Membranous Nephropathy," a review published in 2017.

Conclusion

This study shows that there has been increasing interest in membranous nephropathy over the past 13 years. The most frequently encountered keywords were "membranous nephropathy" "nephrotic syndrome," and "glomerulonephritis." Analysis of emerging terms indicated that "a2 receptor antibody," "domain containing 7a," and "t cell" may remain prominent subjects of research in the forthcoming years. The findings highlight key research trends and areas of interest that can inform researchers, clinicians, and policymakers about the current state of MN research and help guide future research directions and clinical practice.

Therapeutic targets in membranous nephropathy: plasma cells and complement

Membranous nephropathy (MN) is an antibody-mediated autoimmune disease and the most common cause of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor 1 (PLA2R1) as the first target antigen in patients with MN 15 years ago has led to a paradigm shift in the pathobiological understanding of this disease. Autoantibodies against PLA2R1 as well as thrombospondin type-1 domain-containing 7A, the second identified antigen in adults, were shown to be disease-causing and act through local activation of the complement system, primarily via the classical and lectin pathways. These findings indicate that both plasma cells, the main source of antibodies and autoantibodies, as well as the complement system, the main pathogenic effector mechanism in MN, are rational and pathogenesis-based treatment targets in MN. This review summarizes pathomechanistic and clinical evidence for and against plasma cell- and complement-targeted treatments in MN.

Future embracing: exosomes driving a revolutionary approach to the diagnosis and treatment of idiopathic membranous nephropathy

Membranous nephropathy (MN) is a leading cause of nephrotic syndrome in adults and is associated with high rates of end-stage renal disease. Early detection and precise interventions are crucial for improving patient prognosis and quality of life. However, the current diagnosis primarily relies on renal biopsies and traditional biomarkers, which have limitations. Additionally, targeted therapeutic strategies are lacking. Exosomes, small vesicles that facilitate intercellular communication, have emerged as potential noninvasive diagnostic markers due to their stability, diverse cargo, and rapid detectability. They also hold promise as carriers for gene and drug delivery, presenting innovative opportunities in renal disease prognosis and treatment. However, research on exosomes in the context of idiopathic membranous nephropathy (IMN) remains limited, with a focus on exploring urinary exosomes as IMN markers. In this review, we summarize the current status of MN diagnosis and treatment, highlight the fundamental characteristics of exosomes, and discuss recent advancements in their application to IMN diagnosis and therapy. We provide insights into the clinical prospects of exosomes in IMN and acknowledge potential challenges. This article aims to offer forward-looking insights into the future of exosome-mediated IMN diagnosis and treatment, indicating a revolutionary transformation in this field.

Obinutuzumab as Initial or Second-Line Therapy in Patients With Primary Membranous Nephropathy

Introduction

B-cell lymphocytes have been demonstrated to play a key role in the pathogenesis underlying membranous nephropathy (MN). The aim of this study was to evaluate the therapeutic efficacy and safety of Obinutuzumab, a glycoengineered type II anti-CD20 monoclonal antibody in individuals with MN.

Methods

We retrospectively analyzed data from 59 consecutive patients with primary MN who provided consent to receive Obinutuzumab and were followed for at least 6 months. The primary outcomes were complete (proteinuria <0.3 g/d) or partial (proteinuria <3.5 g/d with ≥ 50% reduction) remission of proteinuria.

Results

Twenty patients received Obinutuzumab as initial therapy, and 39 patients were previously treated with at least 1 immunosuppressant (second-line therapy). Fifty patients (84.7%) achieved complete remission (CR) or partial remission (PR) of proteinuria during the median follow-up of 9.4 months. The likelihood of remission was significantly higher when Obinutuzumab was used as initial therapy than as second-line therapy after adjusting for the baseline estimated glomerular filtration rate (eGFR), 24-hour urinary protein levels, and anti-phospholipase A2 receptor (PLA2R) status (adjusted hazard ratio [HR], 4.5; 95% confidence interval [CI]: 2.1-9.5, P < 0.001). Circulating CD19+ B-cell count decreased to <5 cells/μl in all patients within 2 weeks after infusion. Serum anti-PLA2R concentrations decreased to <14 relative units (RU)/ml in 43 of 48 patients with PLA2R-related MN. After Obinutuzumab administration, a significant reduction in 24-hour urine protein and increase in serum albumin were observed. No serious adverse events were observed.

Conclusion

Obinutuzumab may represent a promising and well-tolerated therapeutic option for individuals with primary MN. The potential of Obinutuzumab was highlighted as an initial therapy for primary MN.

Environmental pollution to kidney disease: an updated review of current knowledge and future directions

Environmental pollution significantly impacts global disease burden. However, the contribution of environmental pollution to kidney disease is often overlooked in nephrology. This review examines the growing body of research demonstrating the significant impacts of environmental pollutants, with a focus on air pollution as a primary factor, and acknowledges the roles of other pollutants, such as heavy metals, in the development and progression of kidney diseases. Short-term exposure to air pollution is linked with an increased risk of kidney disease-related events, including hospital admissions, and death, predominantly occurring in vulnerable populations. In contrast, long-term exposure, even at low to moderate levels, may lead to progressive pathophysiological changes, such as chronic systemic inflammation and oxidative stress, that contribute to the development of kidney disease. In addition, air pollution may exacerbate traditional kidney disease risk factors such as hypertension and diabetes, thereby accelerating disease progression. The review also explores how climate change may interact with various pollutants, including air pollution, influencing kidney disease indirectly. The examined evidence underscores the urgent need for an interdisciplinary approach to research further into environmental kidney disease. Environmental health policies could play a crucial role in the prevention, intervention, and improvement of kidney health worldwide.

Air quality and kidney health: Assessing the effects of PM10, PM2.5, CO, and NO2 on renal function in primary glomerulonephritis

BACKGROUND

While extensive studies have elucidated the relationships between exposure to air pollution and chronic diseases, such as cardiovascular disorders and diabetes, the intricate effects on specific kidney diseases, notably primary glomerulonephritis (GN)-an immune-mediated kidney ailment-are less well understood. Considering the escalating incidence of GN and conspicuous lack of investigative focus on its association with air quality, investigation is dedicated to examining the long-term effects of air pollutants on renal function in individuals diagnosed with primary GN.

METHODS

This retrospective cohort analysis was conducted on 1394 primary GN patients who were diagnosed at Seoul National University Bundang Hospital and Seoul National University Hospital. Utilizing time-varying Cox regression and linear mixed models (LMM), we examined the effect of yearly average air pollution levels on renal function deterioration (RFD) and change in estimated glomerular filtration rate (eGFR). In this context, RFD is defined as sustained eGFR of less than 60 mL/min per 1.73 m2.

RESULTS

During a mean observation period of 5.1 years, 350 participants developed RFD. Significantly, elevated interquartile range (IQR) levels of air pollutants-including PM10 (particles ≤10 micrometers, HR 1.389, 95 % CI 1.2-1.606), PM2.5 (particles ≤2.5 micrometers, HR 1.353, 95 % CI 1.162-1.575), CO (carbon monoxide, HR 1.264, 95 % CI 1.102-1.451), and NO2 (nitrogen dioxide, HR 1.179, 95 % CI 1.021-1.361)-were significantly associated with an increased risk of RFD, after factoring in demographic and health variables. Moreover, exposure to PM10 and PM2.5 was associated with decreased eGFR.

CONCLUSIONS

This study demonstrates a substantial link between air pollution exposure and renal function impairment in primary GN, accentuating the significance of environmental determinants in the pathology of immune-mediated kidney diseases.

Podocyte Pathogenic Bone Morphogenetic Protein-2 Pathway and Immune Cell Behaviors in Primary Membranous Nephropathy

Primary membranous nephropathy (PMN) is one of the leading causes of end-stage renal disease, and the most frequent cause of massive proteinuria in nondiabetic adults, resulting in fatal complications. However, the underlying pathomechanisms of PMN remain largely unclear. Here, single-cell RNA sequencing is employed to analyze kidney biopsies from eleven PMN patients and seven healthy subjects. Profiling 44 060 cells from patients allowed us to characterize the cellular composition and cell-type-specific gene expression in the PMN kidney. The complement-induced BMP2/pSMAD1/COL4 pathway is identified as the pathogenic pathway in podocytes, bridging two key events, i.e., complement system activation and glomerular basement membrane thickening in PMN. Augmented infiltration and activation of myeloid leukocytes and B lymphocytes are found, profiling delicate crosstalk of immune cells in PMN kidneys. Overall, these results provide valuable insights into the roles of podocytes and immune cells in PMN, and comprehensive resources toward the complete understanding of PMN pathophysiology.

Elevated Exposure to Air Pollutants Accelerates Primary Glomerular Disease Progression

Introduction

Environmental contributors to kidney disease progression remain elusive. We explored how residential air pollution affects disease progression in patients with primary glomerulopathies.

Methods

Nephrotic Syndrome Study Network (NEPTUNE) and CureGlomerulonephropathy (CureGN) participants with residential census tract data and ≥2 years of follow-up were included. Using Cox proportional hazards models, the associations per doubling in annual average baseline concentrations of total particulate matter with diameter ≤2.5 μm (PM2.5) and its components, black carbon (BC), and sulfate, with time to ≥40% decline in estimated glomerular filtration rate (eGFR) or kidney failure were estimated. Serum tumour necrosis factor levels and kidney tissue transcriptomic inflammatory pathway activation scores were used as molecular markers of disease progression.

Results

PM2.5, BC, and sulfate exposures were comparable in NEPTUNE (n = 228) and CureGN (n = 697). In both cohorts, participants from areas with higher levels of pollutants had lower eGFR, were older and more likely self-reported racial and ethnic minorities. In a fully adjusted model combining both cohorts, kidney disease progression was associated with PM2.5 (adjusted hazard ratio 1.55 [95% confidence interval: 1.00-2.38], P = 0.0489) and BC (adjusted hazard ratio 1.43 [95% confidence interval: 0.98-2.07], P = 0.0608) exposure. Sulfate and PM2.5 exposure were positively correlated with serum tumour necrosis factor (TNF) (P = 0.003) and interleukin-1β levels (P = 0.03), respectively. Sulfate exposure was also directly associated with transcriptional activation of the TNF and JAK-STAT signaling pathways in kidneys (r = 0.55-0.67, P-value <0.01).

Conclusion

Elevated exposure to select air pollutants is associated with increased risk of disease progression and systemic inflammation in patients with primary.

Blood and urine biomarkers of disease progression in IgA nephropathy

The prognosis of patients with IgA nephropathy (IgAN) is variable but overall not good. Almost all patients with IgAN are at risk of developing end-stage renal disease within their expected lifetime. The models presently available for prediction of the risk of progression of IgAN, including the International IgA Nephropathy Prediction Tool, consist of traditional clinical, pathological, and therapeutic indicators. Finding biomarkers to improve the existing risk prediction models or replace pathological indicators is important for clinical practice. Many studies have attempted to identify biomarkers for prediction of progression of IgAN, such as galactose-deficient IgA1, complement, a spectrum of protein biomarkers, non-coding RNA, and shedding cells. This article reviews the biomarkers of progression of IgAN identified in recent years, with a focus on those with clinical value, in particular the combination of multiple biomarkers into a biomarker spectrum. Future research should focus on establishing a model based primarily on biomarkers that can predict progression of IgAN and testing it in various patient cohorts.

Effects of particulate matter (PM2.5) concentration and components on mortality in chronic kidney disease patients: a nationwide spatial-temporal analysis

Chronic kidney disease (CKD) is a major global public health issue and the leading cause of death in Thailand. This study investigated the spatial-temporal association between PM2.5 and its components (organic carbon, black carbon, dust, sulfate, and sea salt) and CKD mortality in Thailand from 2012 to 2021. The Modern-Era Retrospective analysis for Research and Application version 2 (MERRA-2), a NASA atmospheric satellite model, was assessed for the temporal data of PM2.5 concentration and aerosol components. Spatial resources of 77 provinces were integrated using the Geographical Information System (GIS). Multivariate Poisson regression and Bayesian inference analyses were conducted to explore the effects of PM2.5 on CKD mortality across the provinces. Our analysis included 718,686 CKD-related deaths, resulting in a mortality rate of 1107 cases per 100,000 population where was the highest rate in Northeast region. The average age of the deceased was 72.43 ± 13.10 years, with males comprising 50.46% of the cases. Adjusting for age, sex, underlying diseases, co-morbidities, CKD complications, replacement therapy, population density, and income, each 1 µg/m3 increase in PM2.5, black carbon, dust, sulfate, and organic carbon was significantly associated with increased CKD mortality across 77 provinces. Incidence rate ratios were 1.04 (95% CI 1.03-1.04) for PM2.5, 1.11 (95% CI 1.10-1.13) for black carbon, 1.24 (95% CI 1.22-1.25) for dust, 1.16 (95% CI 1.16-1.17) for sulfate, and 1.05 (95% CI 1.04-1.05) for organic carbon. These findings emphasize the significant impact of PM2.5 on CKD mortality and underscore the need for strategies to reduce PM emissions and manage CKD co-morbidities effectively.

A review of progress on complement and primary membranous nephropathy

Primary membranous nephropathy (PMN) is a predominant cause of adult nephrotic syndrome, with its incidence witnessing a progressive surge over time. Approximately 35% to 47% of patients progress to renal failure within 10 years, causing a huge social burden. Within China, the proportion of PMN in primary glomerular disease exhibits a gradual ascension. Recent studies have shown that the 3 activation pathways of complement: the classical pathway, mannose-binding lectin pathway, and alternative pathway, are all involved in the pathogenesis of PMN. Despite historical limitations in detecting C1q deposits on the glomeruli of PMN in the past, recent studies have confirmed the classical pathway is implicated in patients with PMN. Considering the dysregulation of the complement system has been observed in PMN, complement inhibitors become increasingly promising. Several clinical trials are presently underway to evaluate the efficacy of complement inhibitors, such as MASP2 antagonists (OMS721), C3 and C3b antagonists (APL2), FD inhibitors (BCX9930), C3aR antagonists (SB290157 and JR14a), FB inhibitors (LNP023). This article reviews the recent research progress on the role of the complement pathway in the pathogenesis of PMN, and underscores the importance of continued research into the complement pathway and its inhibitors, which may pave the way for groundbreaking advancements in the management of PMN.

A single-center, open label, randomized, controlled study of hydroxychloroquine sulfate in the treatment of low risk PLA2R-associated membranous nephropathy

OBJECTIVE

To evaluate the efficacy and safety of hydroxychloroquine sulfate (HCQ) in the treatment of low risk phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN).

METHODS

A total of 110 patients with low risk PLA2R-associated MN were included in the study. Patients who met the inclusion and exclusion criteria were assigned randomly to two groups: the HCQ treatment group and the control group. The control group received standard supportive treatment according to the guidelines, while the HCQ treatment group received HCQ in addition to the supportive treatment. The clinical data of the patients were analyzed, with comparisons made at baseline and during the six-month follow-up period. Any adverse reactions were recorded.

RESULTS

The baseline data were comparable between the HCQ treatment group and the control group. At the end of the six-month follow-up period, the reductions in urine protein excretion and serum PLA2R antibody titer were more notable in the HCQ treatment group than those in the control group, with these differences being statistically significant (p < 0.05). Compared to the control group, the HCQ treatment group had fewer patients who were converted from low risk to moderate-to-high risk (p = 0.084). There were also no severe adverse reactions in the HCQ treatment group.

CONCLUSION

In patients with low risk PLA2R-associated MN, adequate supportive therapy combined with HCQ is superior to supportive therapy alone in controlling proteinuria and reducing serum PLA2R antibody titers. Additionally, our study demonstrated that the incidence of adverse reactions did not increase.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (Registration No.: ChiCTR1900021757, Date of registration: 2019-03-08).

Efficacy of sulodexide in treating idiopathic membranous nephropathy among Chinese patients: a meta-analysis

OBJECTIVE

To evaluate the efficacy of Sulodexide in treating idiopathic membranous nephropathy (IMN) in the Chinese population.

METHODS

We systematically reviewed all eligible randomized clinical trials (RCTs) conducted in China that investigated the effects of Sulodexide on IMN. Three RCTs published between 2013 and 2022 were included, encompassing a total of 146 patients. The primary outcomes evaluated were changes in urine total protein (UTP), serum albumin (ALB), cholesterol (CHOL), and fibrinogen (FIB) levels.

RESULTS

Statistically significant differences were observed in the Sulodexide treatment group compared to the control group for the following parameters: reduction in UTP and CHOL, increase in ALB, and reduction in FIB levels.

CONCLUSION

Sulodexide, when combined with conventional therapy, effectively reduces UTP and CHOL levels, decreases FIB levels, and increases ALB in Chinese patients with IMN.

Mannose-Binding Lectin Deposition in Membranous Nephropathy and Differentiation of Primary from Secondary Forms

The differentiation between primary and secondary forms of membranous nephropathy (MN) is a cornerstone that is necessary for adequate decision making regarding the treatment options and behavior of each specific case. Kidney biopsy and antibody results can be controversial, and a unique biomarker has still not been found.

BACKGROUND AND OBJECTIVES

We investigated the lack of mannose-binding lectin (MBL) deposition in patients with secondary MNs (sMNs) with the presence of IgG4 deposition in relation to the presence of MBL deposition in patients with primary MNs (pMNs). We also established a connection between the stage of MN and MBL deposition.

MATERIALS AND METHODS

Materials from 72 renal biopsies with proven MN were used for immunohistochemistry staining (IHC) for the phospholipase A2 receptor (PLA2R), immunoglobulin subtype IgG4, and MBL. Patients were separated into one of the following three groups: primary MN (pMN), idiopathic MN (iMN), and secondary MN (sMN). Serum antibodies for PLA2R and thrombospondin type-I-domain-containing 7A (THSD7A) were also used for the precise evaluation of the type of MN, as well as for detecting positivity for PLA2R using IHC. Which stage of MN was present in relation to the deposition of MBL was evaluated.

RESULTS

In total, 50 patients were positive for IgG4, 34 with pMN, 12 with iMN, and 4 with sMN. A total of 20 patients were positive for MBL, 14 with pMN and 6 with iMN; no MBL deposits were found in patients with sMN. MBL positivity was predominantly present in the first two stages of MN, with a gradual reduction in the later stages.

CONCLUSIONS

The activation of the lectin-complement pathway occurs in the early stages of the disease and is associated with the deposition of IgG4; IgG4 deposition is present in sMN, but there is no MBL deposition. IgG4 cannot be used for the differentiation of primary from secondary MNs, but the lack of MBL can be used as a marker for sMN in the early stages of the disease.

Membranous Nephropathy: Updates on Management

Membranous nephropathy is a major etiology of nephrotic syndrome in adults and less frequently in children. Circulating antibodies to intrinsic podocyte antigens, such as M-type phospholipase A2 receptor, or to extrinsic proteins accumulate beneath the podocyte to cause damage via complement activation and/or other mechanisms. The availability of clinical testing for autoantibodies to M-type phospholipase A2 receptor has allowed noninvasive diagnosis of this form of membranous nephropathy and a means to monitor immunologic activity to guide immunosuppressive therapy. Treatment of membranous nephropathy includes optimal supportive care with renin-angiotensin-system blockers, lipid-lowering agents, diuretics, lifestyle changes, and additional immunosuppressive therapy in patients with an increased risk of progression to kidney failure. Rituximab has been recognized as a first-line immunosuppressive therapy for most membranous nephropathy patients with an increased risk of progressive disease, except those with life-threatening nephrotic syndrome or rapidly deteriorating kidney function from membranous nephropathy. This article discusses the major and minor antigens described in membranous nephropathy, the natural history of the disease, and guidelines for clinical management and immunosuppressive treatment.

Membranous nephropathy: pathogenesis and treatments

Membranous nephropathy (MN), an autoimmune disease, can manifest at any age and is among the most common causes of nephrotic syndrome in adults. In 80% of cases, the specific etiology of MN remains unknown, while the remaining cases are linked to drug use or underlying conditions like systemic lupus erythematosus, hepatitis B virus, or malignancy. Although about one-third of patients may achieve spontaneous complete or partial remission with conservative management, another third face an elevated risk of disease progression, potentially leading to end-stage renal disease within 10 years. The identification of phospholipase A2 receptor as the primary target antigen in MN has brought about a significant shift in disease management and monitoring. This review explores recent advancements in the pathophysiology of MN, encompassing pathogenesis, clinical presentations, diagnostic criteria, treatment options, and prognosis, with a focus on emerging developments in pathogenesis and therapeutic strategies aimed at halting disease progression. By synthesizing the latest research findings and clinical insights, this review seeks to contribute to the ongoing efforts to enhance our understanding and management of this challenging autoimmune disorder.

The co-occurrence of sarcoidosis and anti-PLA2R-associated membranous nephropathy in a patient with underlying genetic susceptibility

BACKGROUND

Sarcoidosis is a multisystemic inflammatory disease, characterized by the presence of non-caseating, epithelioid granulomas. Glomerular disease in patients with sarcoidosis is rare and membranous nephropathy (MN) is cited as the most common. The association between the two diseases remained unclear. This article reported a case of co-occurrence of sarcoidosis and anti-PLA2R-associated MN, to provide a possible relationship between these two entities.

CASE PRESENTATION

A 61-year-old Chinese Han woman with a history of sarcoidosis was admitted to our hospital for nephrotic syndrome. Her sarcoidosis was diagnosed according to the adenopathy observed on the computed tomography scan and the biopsy of lymph nodes. The MN presented with nephrotic syndrome with a PLA2R antibody titer of 357RU/ml, and the final diagnosis was based on a renal biopsy. The patient's sarcoidosis was remitted after treatment with prednisone. One year later MN was diagnosed, and she was treated with prednisone combined with calcineurin inhibitors, based on a full dose of renin-angiotensin system (RAS) inhibitor. The patient's sarcoidosis had been in remission while the MN was recurrent, and her renal function deteriorated to end-stage renal disease 6 years later due to discontinuation of immunosuppression. A genetic test led to the identification of the HLA-DRB1*0301 and HLA-DRB1*150 genes associated with both sarcoidosis and MN, which provides a new possible explanation of the co-occurrence of these two diseases.

CONCLUSION

This case suggested for the first time a potential genetic connection between idiopathic MN and sarcoidosis which needs further studies in the future.

Demographic distribution analysis of different glomerular diseases in Southwest China from 2008 to 2022

BACKGROUND

Environmental and lifestyle factors play an etiological role in the pathogenesis of different glomerular diseases. Thus, exploring the epidemic characteristics of renal disease in different nationalities and regions is important.

MATERIALS AND METHODS

Patients who underwent renal biopsy from October 2008 to October 2022 were included. The proportion and change tendency of glomerular diseases and the differences between the sexes and different ages and races were analyzed.

RESULTS

There were 15,146 cases of glomerular diseases (98.5%), involving 7538 males (49.8%) and 7608 females (50.2%). The mean age was 37.0 years (range 0-80 years). The proportion of membranous nephropathy (MN) and diabetic nephropathy (DN) showed an increased trend. The most common primary glomerulonephritis (PGN) was IgA nephropathy (IgAN, 44.6%), followed by minimal-change disease (MCD, 24.3%) and MN (15.4%). Lupus nephritis (LN, 30%) accounted for the largest proportion of SGNs, followed by Henoch-Schonlein purpura nephritis (HSPN, 20.9%) and DN (19.8%). Compared with adults aged 18-60 years old, MCD and HSPN were more common in children and MN and DN in elderly individuals, statistically significant differences. Additionally, the sex and age distribution of PGN and SGN between the Tibetan and Han populations differed significantly, whereby LN was higher in the Han population and HSPN in the Tibetan population.

CONCLUSION

The distribution of glomerular diseases showed age, sex and race differences. This research will be beneficial for providing epidemiological evidence for clinical diagnosis, disease prevention and public health decision-making.

The role of mitochondrial dysfunction in kidney injury and disease

Mitochondria are the main sites of aerobic respiration in the cell and mainly provide energy for the organism, and play key roles in adenosine triphosphate (ATP) synthesis, metabolic regulation, and cell differentiation and death. Mitochondrial dysfunction has been identified as a contributing factor to a variety of diseases. The kidney is rich in mitochondria to meet energy needs, and stable mitochondrial structure and function are essential for normal kidney function. Recently, many studies have shown a link between mitochondrial dysfunction and kidney disease, maintaining mitochondrial homeostasis has become an important target for kidney therapy. In this review, we integrate the role of mitochondrial dysfunction in different kidney diseases, and specifically elaborate the mechanism of mitochondrial reactive oxygen species (mtROS), autophagy and ferroptosis involved in the occurrence and development of kidney diseases, providing insights for improved treatment of kidney diseases.

Gut-bone axis research: unveiling the impact of gut microbiota on postmenopausal osteoporosis and osteoclasts through Mendelian randomization

Background

Postmenopausal osteoporosis is a prevalent disease that affects the bone health of middle-aged and elderly women. The link between gut microbiota and bone health, known as the gut-bone axis, has garnered widespread attention.

Methods

We employed a two-sample Mendelian randomization approach to assess the associations between gut microbiota with osteoclasts and postmenopausal osteoporosis, respectively. Single nucleotide polymorphisms associated with the composition of gut microbiota were used as instrumental variables. By analyzing large-scale multi-ethnic GWAS data from the international MiBioGen consortium, and combining data from the eQTLGen consortium and the GEFOS consortium, we identified microbiota related to osteoclasts and postmenopausal osteoporosis. Key genes were further identified through MAGMA analysis, and validation was performed using single-cell data GSE147287.

Results

The outcomes of this study have uncovered significant associations within the gut microbiome community, particularly with the Burkholderiales order, which correlates with both an increase in osteoclasts and a reduced risk of postmenopausal osteoporosis. with an odds ratio (OR) of 0.400, and a P-value of 0.011. Further analysis using single-cell data allowed us to identify two key genes, FMNL2 and SRBD1, that are closely linked to both osteoclasts and osteoporosis.

Conclusion

This study utilizing Mendelian randomization and single-cell data analysis, provides new evidence of a causal relationship between gut microbiota and osteoclasts, as well as postmenopausal osteoporosis. It was discovered that the specific microbial group, the Burkholderiales order, significantly impacts both osteoporosis and osteoclasts. Additionally, key genes FMNL2 and SRBD1 were identified, offering new therapeutic strategies for the treatment of postmenopausal osteoporosis.

Efficacy of tacrolimus monotherapy in primary membranous nephropathy

Objective

The aim of this study was to observe the remission of primary membranous nephropathy (PMN) and evaluate the efficacy of tacrolimus (TAC) monotherapy for PMN in comparison with TAC combined with a low-dose glucocorticoid (GC) protocol (TAC + GC).

Methods

This was tested in a prospective monocentric observational trial of 70 patients with PMN, of whom 34 received TAC (0.05-0.075 mg/kg/day) or 36 received TAC (0.05-0.075 mg/kg/day) and GC (0.3-0.5 mg/kg/day of prednisone).

Results

At 3, 6, 9, and 12 months of treatment, the effective rates in the TAC group and the TAC + GC group were similar (P > 0.05). The urinary protein quantification was reduced in patients under both therapeutic protocols, and the differences in the proteinuria quantification at 3, 6, 9, and 12 months of treatment were not statistically significant between the two groups (P > 0.05). The overall incidence of adverse reactions in the TAC group was lower than that in the TAC + GC group (23.5% < 36.1%), and the difference was statistically significant (P < 0.05).

Conclusion

TAC monotherapy for PMN could effectively reduce urinary protein quantification and increase serum albumin levels. Compared with TAC + GC, TAC monotherapy for PMN had no difference in efficacy and fewer incidences of adverse reactions.

Effectiveness and safety of tripterygium wilfordii poly-glycosides on glomerulonephritis: a systematic review and meta-analysis

Treatment of glomerulonephritis presents several challenges, including limited therapeutic options, high costs, and potential adverse reactions. As a recognized Chinese patent medicine, Tripterygium wilfordii poly-glycosides (TWP) have shown promising benefits in managing autoimmune diseases. To evaluate clinical effectiveness and safety of TWP in treating glomerulonephritis, we systematically searched PubMed, Cochrane Library, Web of Science, and Embase databases for controlled studies published up to 12 July 2023. We employed weighted mean difference and relative risk to analyze continuous and dichotomous outcomes. This meta-analysis included 16 studies that included primary membranous nephropathy (PMN), type 2 diabetic kidney disease (DKD), and Henoch-Schönlein purpura nephritis (HSPN). Analysis revealed that additional TWP administration improved patients' outcomes and total remission rates, reduced 24-h urine protein (24hUP) and decreased relapse events. The pooled results demonstrated the non-inferiority of TWP to glucocorticoids in achieving total remission, reducing 24hUP, and converting the phospholipase A2 receptor (PLA2R) status to negative. For DKD patients, TWP effectively reduced 24hUP levels, although it did not significantly improve the estimated glomerular filtration rate (eGFR). Compared to valsartan, TWP showed comparable improvements in 24hUP and eGFR levels. In severe cases of HSPN in children, significant clinical remission and a reduction in 24hUP levels were observed with the addition of TWP treatment. TWP did not significantly increase the incidence of adverse reactions. Therefore, TWP could offer therapeutic benefits to patients with PMN, DKD, and severe HSPN, with a minimal increase in the risk of side effects.

A simple protocol to establish a conditionally immortalized mouse podocyte cell line

Podocytes are specialized terminally differentiated cells in the glomerulus that are the primary target cells in many glomerular diseases. However, the current podocyte cell lines suffer from prolonged in vitro differentiation and limited survival time, which impede research progress. Therefore, it is necessary to establish a cell line that exhibits superior performance and characteristics. We propose a simple protocol to obtain an immortalized mouse podocyte cell (MPC) line from suckling mouse kidneys. Primary podocytes were cultured in vitro and infected with the SV40 tsA58 gene to obtain immortalized MPCs. The podocytes were characterized using Western blotting and quantitative real-time PCR. Podocyte injury was examined using the Cell Counting Kit-8 assay and flow cytometry. First, we successfully isolated an MPC line and identified 39 °C as the optimal differentiation temperature. Compared to undifferentiated MPCs, the expression of WT1 and synaptopodin was upregulated in differentiated MPCs. Second, the MPCs ceased proliferating at a nonpermissive temperature after day 4, and podocyte-specific proteins were expressed normally after at least 15 passages. Finally, podocyte injury models were induced to simulate podocyte injury in vitro. In summary, we provide a simple and popularized protocol to establish a conditionally immortalized MPC, which is a powerful tool for the study of podocytes.

Significance of the total renal chronicity score in predicting renal outcome in PLA2R-associated membranous nephropathy

BACKGROUND

Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy accounts for the majority of membranous nephropathy; however, few studies have determined the prognostic impact and clinical application of renal pathologic change on this disease.

METHODS

A retrospective cohort study of 262 patients with PLA2R-associated membranous nephropathy was conducted. The total renal chronicity score calculated according to the degree of glomerulosclerosis, interstitial fibrosis, tubular atrophy, and arteriosclerosis was applied to evaluate renal chronicity. Baseline bias was adjusted by inverse probability weight when assessing the prognostic impact of chronicity, and multiple parameters were used to evaluate the application value of renal chronicity.

RESULTS

During a median follow-up of 24.5 months, renal outcome (kidney function deterioration and/or end-stage kidney disease) was observed in 22 (8.40%) patients. Not only did a higher total renal chronicity score independently predict renal outcome [odds ratio (OR): 1.562, 95% confidence interval (CI) 1.073-2.273, P = 0.020], but non-minimal chronicity was also an independent risk factor for renal outcome (OR: 3.170, 95% CI 1.040-9.659, P = 0.042). Moreover, the membranous nephropathy risk classification in the Kidney Disease: Improving Global Outcomes (KDIGO) guideline integrated with non-minimal chronicity showed improvements in categorical net reclassification (0.174, 95% CI 0.012-0.335, P = 0.035), continuous net reclassification (0.462, 95% CI 0.087-0.838, P = 0.016), and integrated discrimination (0.019, 95% CI 0.003-0.035, P = 0.020) compared to the original classification.

CONCLUSIONS

Renal chronicity is closely associated with renal outcomes in PLA2R-associated membranous nephropathy, and combining the KDIGO risk classification with chronicity scores may provide a more accurate prognostic prediction.

A Case of NELL-1-Positive Membranous Nephropathy With Acute Kidney Injury Due to Bilateral Renal Vein Thrombosis

Membranous nephropathy (MN) is a significant cause of nephrotic syndrome in non-diabetic adults. It can be primary, attributed to autoantibodies targeting podocyte antigens, or secondary to various disorders. Although rare, nerve epidermal growth factor-like 1 (NELL-1)-associated MN presents diagnostic and management challenges. Thrombotic complications such as renal vein thrombosis (RVT) are recognized but less reported, especially in NELL-1-positive MN. We report a 43-year-old male with NELL-1-positive MN complicated by acute kidney injury (AKI) due to bilateral RVT, treated successfully with thrombolysis. Histopathological analysis confirmed MN with specific immunohistochemical staining for NELL-1. Treatment included immunosuppressive therapy and tailored anticoagulation. This case emphasizes recognizing thrombotic complications in MN, particularly in NELL-1-positive cases. Further research is needed to explore serum anti-NELL-1 antibodies as biomarkers and optimal anticoagulation strategies in MN patients at risk of thrombotic events to improve outcomes and guide personalized management.

Combined Serologic and Genetic Risk Score and Prognostication of Phospholipase A2 receptor-Associated Membranous Nephropathy

INTRODUCTION

The aim of this study was to test whether a combined risk score on the basis of genetic risk and serology can improve the prediction of kidney failure in phospholipase A2 receptor (PLA2R)-associated primary membranous nephropathy.

METHODS

We performed a retrospective analysis of 519 biopsy-proven PLA2R-associated primary membranous nephropathy patients with baseline eGFR ≥25 ml/min per 1.73 m 2 . The combined risk score was calculated by combining the genetic risk score with PLA2R ELISA antibody titers. The primary end point was kidney disease progression defined as a 50% reduction in eGFR or kidney failure. Cox proportional hazard regression analysis and C-statistics were applied to compare the performance of PLA2R antibody, genetic risk score, and combined risk score, as compared with clinical factors alone, in predicting primary outcomes.

RESULTS

The median age was 56 years (range, 15-82 years); the male-to-female ratio was 1:0.6, the median eGFR at biopsy was 99 ml/min per 1.73 m 2 (range: 26-167 ml/min per 1.73 m 2 ), and the median proteinuria was 5.3 g/24 hours (range: 1.5-25.8 g/24 hours). During a median follow-up of 67 (5-200) months, 66 (13%) had kidney disease progression. In Cox proportional hazard regression models, PLA2R antibody titers, genetic risk score, and combined risk score were all individually associated with kidney disease progression with and without adjustments for age, sex, proteinuria, eGFR, and tubulointerstitial lesions. The best-performing clinical model to predict kidney disease progression included age, eGFR, proteinuria, serum albumin, diabetes, and tubulointerstitial lesions (C-statistic 0.76 [0.69-0.82], adjusted R 2 0.51). Although the addition of PLA2R antibody titer improved the performance of this model (C-statistic: 0.78 [0.72-0.84], adjusted R 2 0.61), replacing PLA2R antibody with the combined risk score improved the model further (C-statistic: 0.82 [0.77-0.87], adjusted R 2 0.69, difference of C-statistics with clinical model=0.06 [0.03-0.10], P < 0.001; difference of C-statistics with clinical-serologic model=0.04 [0.01-0.06], P < 0.001).

CONCLUSIONS

In patients with PLA2R-associated membranous nephropathy, the combined risk score incorporating inherited risk alleles and PLA2R antibody enhanced the prediction of kidney disease progression compared with PLA2R serology and clinical factors alone.

Management and Clinical Outcomes of Membranous Nephropathy, IgA Nephropathy, and Minimal Change Disease Two Years Post-Kidney Biopsy

INTRODUCTION

This study evaluated the phenotypic and pathology characteristics of patients undergoing kidney biopsy at a single center, while also determining the frequency and factors associated with clinical outcomes.

METHODS

The incidence and distribution of biopsy-proven kidney diseases in 2000-2019 were surveyed. Consecutive individuals diagnosed with membranous nephropathy (MN), immunoglobulin A nephropathy (IgAN), and minimal change disease (MCD) between August 2015 and December 2019 were enrolled in the prospective 2-year follow-up study. Outcomes included remission of proteinuria and kidney disease progression events. Multivariable-adjusted Cox proportional hazards model was applied.

RESULTS

4,550 kidney biopsies were performed in 2000-2019, showing a noticeable increase in the proportion of MN. 426 patients were enrolled in the follow-up cohort. 346 (81.2%) achieved remission of proteinuria, 39 (9.2%) suffered kidney disease progression and 51.3% of them were diagnosed with IgAN. Kidney pathological diagnosis (MN vs. MCD: hazard ratio [HR], 0.42; 95% confidence interval [95% CI], 0.31-0.57; IgAN vs. MCD: 0.58; 0.39-0.85), levels of 24-h urine protein at biopsy (1.04; 1.00-1.08) and presence of nodular mesangial sclerosis (0.70; 0.49-0.99) were significantly correlated with remission of proteinuria after adjusting for baseline variables. 24-h urine protein levels at biopsy (1.14; 1.04-1.25) and the presence of crescents (2.30; 1.06-4.95) were the independent risk factors for kidney disease progression events after adjusting for baseline variables.

CONCLUSION

The increasing frequency of MN has been affirmed over the past 2 decades. The therapeutic status, clinical outcomes, and factors influencing these outcomes were presented in this single-center study for the three primary glomerular diseases.

An Updated Review of Membranous Nephropathy

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. The discovery of phospholipase A2 receptor (PLA2R) as a target antigen has led to a paradigm shift in the understanding and management of MN. At present, serum PLA2R antibodies are used for diagnosis, prognostication, and guiding treatment. Now, with the discovery of more than 20 novel target antigens, antigen mapping is almost complete. The clinical association of certain antigens provides clues for clinicians, such as the association of nerve epidermal growth factor-like 1 with malignancies and indigenous medicines. Serum antibodies are detected for most target antigens, except exostosin 1 and 2 and transforming growth factor-beta receptor 3, but their clinical utility is yet to be defined. Genome-wide association studies and studies investigating environmental factors, such as air pollution, shed more light on the underpinnings of MN. The standard therapy of MN diversified from cyclical cyclophosphamide and steroids to include rituximab and calcineurin inhibitors over the past decades. Here, we provide a cutting-edge review of MN, focusing on genetics, immune system and environmental factors, novel target antigens and their clinical characteristics, and currently available and emerging novel therapies in MN.

Long-term exposure to varying-sized particulate matters and kidney disease in middle-aged and elder adults: A 8-year nationwide cohort study in China

Evidence for the causal relationship of particulate matters (PMs) exposure with kidney disease, especially PM1, PM1-2.5 and PM2.5-10, remained scarce among developing countries with severe pollution. We conducted a longitudinal cohort study involving 13,041 adults with free kidney disease from 150 Chinese counties. PMs concentrations were generated using a well-established satellite-based spatiotemporal model. And the time-varying Cox regression model along with stratified analyses were performed to determine the association and potential modifiers, respectively. We also calculated the population-attributable fraction to evaluate the burden of kidney disease attributable to PMs pollution. Between Jan 2011 and Dec 2018, 985 kidney disease incidents were identified with an incidence rate of 12.69 per 1000 person-years. Significant dose-response relationships were observed for all 5 kinds PMs. Specifically, an increased risk of kidney disease was associated with per 10 μg/m3 increment of PM1 (HR = 1.187, 95%CI: 1.114 to 1.265), PM1-2.5 (1.326, 1.212 to 1.452), PM2.5 (1.197, 1.139 to 1.258), PM2.5-10 (1.297, 1.240 to 1.357), and PM10 (1.137, 1.108 to 1.166). A mixture analysis method of weighted quantile regression model revealed that PM2.5-10 predominated the PMs mixture index (57.1 %), and followed with PM10 (26.4 %). Stratified analyses indicated the elder, overweight persons, smokers, respiratory patients and urban residents were more vulnerable to PMs pollution than their counterparts. Calculated population attributable fractions of kidney disease attributable to PMs pollution was 16.67-39.47 %. Higher PMs pollution was associated with the increased risk of kidney disease development in China. Acceleration of efforts to reduce PMs pollution was therefore urgently needed to alleviate kidney disease burden.

The CXCR4-AT1 axis plays a vital role in glomerular injury via mediating the crosstalk between podocyte and mesangial cell

Glomeruli stand at the center of nephrons to accomplish filtration and albumin interception. Podocytes and mesangial cells are the major constituents in the glomeruli. However, their interdependency in glomerular injury has rarely been reported. Herein, we investigated the role of C-X-C chemokine receptor type 4 (CXCR4) in mediating the crosstalk between podocytes and mesangial cells. We found CXCR4 and angiotensin II (AngII) increased primarily in injured podocytes. However, type-1 receptor of angiotensin II (AT1) and stromal cell-derived factor 1α (SDF-1α), a ligand of CXCR4, were evidently upregulated in mesangial cells following the progression of podocyte injury. Ectopic expression of CXCR4 in 5/6 nephrectomy mice increased the decline of renal function and glomerular injury, accelerated podocyte injury and mesangial cell activation, and initiated CXCR4-AT1 axis signals. Additionally, treatment with losartan, an AT1 blocker, interrupted the cycle of podocyte injury and mesangial matrix deposition triggered by CXCR4. Podocyte-specific ablation of CXCR4 gene blocked podocyte injury and mesangial cell activation. In vitro, CXCR4 overexpression induced oxidative stress and renin angiotensin system (RAS) activation in podocytes, and triggered the communication between podocytes and mesangial cells. In cultured mesangial cells, AngII treatment induced the expression of SDF-1α, which was secreted into the supernatant to further promote oxidative stress and cell injury in podocytes. Collectively, these results demonstrate that the CXCR4-AT1 axis plays a vital role in glomerular injury via mediating pathologic crosstalk between podocytes and mesangial cells. Our findings uncover a novel pathogenic mechanism by which the CXCR4-AT1 axis promotes glomerular injury.

Development and validation of a diagnostic nomogram model for predicting monoclonal gammopathy of renal significance

In patients with kidney disease, the presence of monoclonal gammopathy necessitates the exploration of potential causal relationships. Therefore, in this study, we aimed to address this concern by developing a nomogram model for the early diagnosis of monoclonal gammopathy of renal significance (MGRS). Univariate and multivariate logistic regression analyses were employed to identify risk factors for MGRS. Verification and evaluation of the nomogram model's differentiation, calibration, and clinical value were conducted using the receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis. The study encompassed 347 patients who underwent kidney biopsy, among whom 116 patients (33.4%) were diagnosed with MGRS and 231 (66.6%) with monoclonal gammopathy of undetermined significance. Monoclonal Ig-related amyloidosis (n = 86) and membranous nephropathy (n = 86) was the most common renal pathological type in each group. Notably, older age, abnormal serum-free light chain ratio, and the absence of microscopic hematuria were identified as independent prognostic factors for MGRS. The areas under the ROC curves for the training and verification sets were 0.848 and 0.880, respectively. In conclusion, the nomogram model demonstrated high accuracy and clinical applicability for diagnosing MGRS, potentially serving as a valuable tool for noninvasive early MGRS diagnosis.

Comparative pharmacoeconomic analysis of rituximab and traditional tacrolimus regimens in membranous nephropathy in China

Background: Rituximab (RTX) is a monoclonal antibody that selectively targets CD20 and is frequently used in the treatment of membranous nephropathy (MN). Analysis of the therapeutic efficacy and safety of RTX in treating MN in practice and a comparative pharmacoeconomic analysis of the RTX and traditional tacrolimus (TAC) regimens can provide valuable insights to aid decision-making by the government and relevant medical insurance departments. Methods: We conducted a statistical analysis of medical records from patients diagnosed with MN who underwent RTX treatment between 1 January 2019 and 1 January 2023. The TAC data were obtained from the clinical literature. The efficacy rates and incidence of adverse effects (AEs) were calculated to compare the efficacy and safety of RTX and TAC. Based on the patient's disease status, we developed a Markov model to compare the total cost, remission rate, and incremental cost-effectiveness ratio (ICER) of the two regimens. Both univariate and probability sensitivity analyses were performed to validate the stability of the developed model. Results: The RTX group enrolled 53 patients with MN, and the 12-month overall efficacy rate was not significantly different from that of the TAC group with 35 patients (86.79% vs. 71.4%, p = 0.0131); however, the relapse rate was significantly lower in the RTX group (3.77% vs. 22.8%, p = 0.016). The RTX group demonstrated no severe AEs (SAEs), while the TAC group demonstrated six cases of SAEs, including 4 cases of severe pneumonia, 1 case of lung abscess and 1 case of interstitial lung disease, accounting for 7.89% of traditional tacrolimus-treated patients. The baseline analysis results revealed that over a 5-year post-treatment period, RTX increased quality-adjusted life years (QALYs) by 0.058 and costs by ¥7,341. Assuming three times the 2022 domestic gross domestic product as the willingness-to-pay (WTP) threshold per QALY, the ICER of RTX compared to TAC was ¥124,631.14/QALY, which is less than the WTP threshold of ¥257,094/QALY, indicating that RTX treatment is approximately two times more cost-effective compared to TAC. Conclusion: The current analysis indicates that despite the expensive unit price of RTX, it remains a cost-effective treatment option for MN compared to TAC.

Prediction of biomarkers associated with membranous nephropathy: Bioinformatic analysis and experimental validation

Membranous nephropathy (MN), the most prevalent form of nephrotic syndrome in non-diabetic adults globally, is currently the second most prevalent and fastest-increasing primary glomerular disease in China. Numerous renal disorders are developed partly due to ferroptosis. However, its relationship to the pathogenesis of MN has rarely been investigated in previous studies; actually, ferroptosis is closely linked to the immune microenvironment and inflammatory response, which might affect the entire process of MN development. In this study, we aimed to identify ferroptosis-related genes that are potentially related to immune cell infiltration, which can further contribute to MN pathogenesis. The microarray datasets were downloaded from the Gene Expression Omnibus (GEO) database. Ferroptosis-related differentially expressed genes (FDEGs) were identified, which were further used for functional enrichment analysis. The common genes identified using the Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression algorithm and the support vector machine recursive feature elimination (SVM-RFE) algorithm were used to identify the characteristic genes related to ferroptosis. The feasibility of the 7 genes as a distinguishing factor was assessed using the receiver operating characteristic (ROC) curve, with the area under the curve (AUC) score serving as the evaluation metric. Gene set enrichment analysis (GSEA) and correlation analysis of these genes were further performed. The correlation between the expression of these genes and immune cell infiltration inferred by single sample gene set enrichment analysis (ssGSEA) algorithm was explored. As a result, 7 genes, including NR1D1, YTHDC2, EGR1, ZFP36, RRM2, RELA and PDK4, which were most relevant to immune cell infiltration, were identified to be potential diagnostic genes in MN patients. Next, the signature genes were validated with other GEO datasets. In the subsequent steps, we conducted quantitative real-time fluorescence PCR (qRT-PCR) analysis and immunohistochemistry (IHC) method on the cationic bovine serum albumin (C-BSA) induced membranous nephropathy (MN) rat model and the passive Heymann nephritis (pHN) rat model to examine characteristic genes. Finally, we analysed the mRNA expression patterns of hub genes in MN patients and normal controls using the Nephroseq V5 online platform. In concise terms, our study successfully identified biomarkers specific to MN patients and delved into the potential interplay between these markers and immune cell infiltration. This knowledge bears significance for the diagnosis and prospective treatment strategies for individuals affected by MN.

Experimental models for elderly patients with membranous nephropathy: Application and advancements

Membranous nephropathy (MN) occurs predominantly in middle-aged and elderly individuals and ranks among the most prevalent etiologies of elderly nephrotic syndrome. As an autoimmune glomerular disorder characterized by glomerular basement membrane thickening and immune complex deposition, conventional MN animal models, including the Heymann nephritis rat model and the c-BSA mouse model, have laid a foundation for MN pathogenesis research. However, differences in target antigens between rodents and humans have impeded this work. In recent years, researchers have created antigen-specific MN animal models, primarily centered on PLA2R1 and THSD7A, employing diverse techniques that provide innovative in vivo research platforms for MN. Furthermore, significant advancements have been made in the development of in vitro podocyte models relevant to MN. This review compiles recent antigen-specific MN animal models and podocyte models, elucidates their immune responses and pathological characteristics, and offers insights into the future of MN experimental model development. Our aim is to provide a comprehensive resource for research into the pathogenesis of MN and the development of targeted therapies for older patients with MN to prolong lifespan and improve quality of life.

Monogenic and polygenic concepts in chronic kidney disease (CKD)

Kidney function is strongly influenced by genetic factors with both monogenic and polygenic factors contributing to kidney function. Monogenic disorders with primarily autosomal dominant inheritance patterns account for 10% of adult and 50% of paediatric kidney diseases. However, kidney function is also a complex trait with polygenic architecture, where genetic factors interact with environment and lifestyle factors. Family studies suggest that kidney function has significant heritability at 35-69%, capturing complexities of the genome with shared environmental factors. Genome-wide association studies estimate the single nucleotide polymorphism-based heritability of kidney function between 7.1 and 20.3%. These heritability estimates, measuring the extent to which genetic variation contributes to CKD risk, indicate a strong genetic contribution. Polygenic Risk Scores have recently been developed for chronic kidney disease and kidney function, and validated in large populations. Polygenic Risk Scores show correlation with kidney function but lack the specificity to predict individual-level changes in kidney function. Certain kidney diseases, such as membranous nephropathy and IgA nephropathy that have significant genetic components, may benefit most from polygenic risk scores for improved risk stratification. Genetic studies of kidney function also provide a potential avenue for the development of more targeted therapies and interventions. Understanding the development and validation of genomic scores is required to guide their implementation and identify the most appropriate potential implications in clinical practice. In this review, we provide an overview of the heritability of kidney function traits in population studies, explore both monogenic and polygenic concepts in kidney disease, with a focus on recently developed polygenic risk scores in kidney function and chronic kidney disease, and review specific diseases which are most amenable to incorporation of genomic scores.

The Role of Renal PLA2R Staining Combined with Serum PLA2R Antibody in Membranous Nephropathy Risk Stratification

BACKGROUND

This study aimed to examine the clinicopathological profiles and prognosis of membranous nephropathy in different subtypes classified by serum PLA2R antibody (SAb) and glomerular PLA2R antigen staining (GAg).

METHODS

A total of 372 biopsy-proven membranous nephropathy (MN) cases, unrelated to lupus, with urine protein > 2 g/24 h and eGFR > 25 mL/min/1.73 m2 were included and categorized into four groups according to the presence or absence of PLA2R antibody and glomerular PLA2R antigen staining. Clinical profiles were compared among four subtypes. Treatment response and renal outcomes were compared among four groups with primary MN. Cox and logistic regression models were used to examine the association between time-to-renal progression and early remission within 6 months in the four subgroups with primary MN.

RESULTS

MN patients who were SAb-/GAg+ presented with a more severe disease onset, whereas those who were SAb-/GAg- had a mild clinical manifestation with a higher prevalence of MN-associated secondary causes. During a median follow-up of 79.2 months (IQR: 48.70-97.40), SAb+/GAg- was identified as an independent risk factor for renal progression [HR: 9.17, 95% CI: 2.26-37.16, p < 0.01] and early remission [OR: 0.06, 95% CI: 0.01-0.56, p = 0.01] in primary MN. Additionally, SAb-/GAg- with primary MN showed an independent association with spontaneous remission after adjusting for age, sex, baseline proteinuria, and eGFR (Before adjustment: OR: 8.33, 95% CI: 1.89-36.76, p = 0.0; after adjustment: OR: 12.25, 95% CI: 2.48-60.53, p < 0.01).

CONCLUSION

Our findings indicated that SAb+/GAg-MN patients exhibited a more severe disease onset and had a poorer prognosis, necessitating an aggressive treatment approach. On the other hand, in the SAb-/GAg- group, the elimination of secondary causes should be considered, and a watchful waiting approach may be appropriate.

Changes in spectrum of biopsy-proven kidney diseases within decade: an analysis based on 10 199 cases from South China

PURPOSE

To assess the regional epidemiological trends of kidney diseases over time in the South China using renal biopsy-proven cases.

METHODS

This retrospective observational cohort study was conducted at the Institute of Nephrology, Second Xiangya Hospital of Central South University, and encompasses all patients diagnosed with kidney disease via biopsy from 2012 to 2021.

RESULTS

The study sample consisted of 10 199 native kidneys, with a male-to-female ratio of 0.91:1 and an average age of 38.74 (±14.53) years. Primary glomerular nephropathy, systemic glomerular nephropathy (SGN), tubulointerstitial disease, and hereditary renal diseases accounted for 66.92 (6825)%, 24.49 (2498)%, 8.06 (822)%, and 0.53 (54)%, respectively. The leading pathologies of primary glomerular nephropathy remained the IgA nephropathy. The frequencies of IgA nephropathy and membranous nephropathy increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016. An earlier onset of membranous nephropathy was observed in the age group of 45-59 years compared to previous studies. The leading pathologies of SGN were found to be lupus nephritis (758 cases, 30.45%) and hypertension nephropathy (527 cases, 21.17%). The frequencies of hypertension nephropathy and diabetic nephropathy increased between 2017 and 2021 compared to 2012 and 2016 (P < .001), gradually becoming the leading pathological types of SGN. In elderly patients diagnosed with nephrotic syndrome, the frequencies of amyloidosis significantly increased (P < .01).

CONCLUSION

Our study may provide insights for kidney disease prevention and public health strategies. What is already known on this topic The pathological spectrum of kidney diseases has undergone significant transformations in the past decade, driven by the escalating incidence of chronic diseases. Although there are studies exploring the renal biopsy findings from various regions in China which present both similarities and differences in epidemiology, few large-scale reports from the South China in recent decades were published. What this study adds Our findings reveal the following key observations: (i) increased proportion of middle-aged patients leading to the increasing average age at the time of biopsy；(ii) the frequencies of IgA nephropathy and membranous nephropathy (MN) increased significantly, whereas the frequencies of minimal change disease and focal segmental glomerulosclerosis decreased (P < .001) between 2017 and 2021 than in the years 2012 and 2016; (iii) earlier onset of MN in the age group of 45-59 years old was found in our study; and (iv) a higher frequency of hypertension nephropathy and DN presented over time, and frequency of amyloidosis increased in elderly patients diagnosed with NS. How this study might affect research, practice, or policy This single-center yet a large-scale study of the kidney disease spectrum in South China may provide a reference point for the diagnosis, treatment, and prevention of chronic kidney disease.

Social deprivation and kidney failure due to an undiagnosed nephropathy

BACKGROUND

In France, kidney diseases of undetermined origin account for 5%-20% of all causes of end-stage kidney disease. We investigated the impact of social disadvantage on the lack of aetiological diagnosis of nephropathies.

METHODS

Data from patients who started dialysis in France between 1 January 2017 and 30 June 2018 were extracted from the French Renal Epidemiology and Information Network registry. The social deprivation of each individual was estimated by the European Deprivation Index (EDI) defined by the patient's address. Logistic regression was used to perform mediation analysis to study the potential association between social deprivation and unknown nephropathy.

RESULTS

Of the 7218 patients included, 1263 (17.5%) had unknown kidney disease. A total of 394 (31.4%) patients in the unknown kidney disease belonged to the most deprived quintile of the EDI [fifth quintile (Q5)], vs 1636 (27.5%) patients in the known kidney disease group. In the multivariate analysis, unknown kidney disease was associated with Q5 (odds ratio 1.40, 95% confidence interval 1.12-1.74, P = .003). Mediation analysis did not identify any variables (e.g. obesity, initiation of dialysis in emergency, number of visits to the general practitioner and nephrologist before initiation of dialysis, date of first nephrology consultation) that mediated the association between social deprivation and nephropathy of unknown origin.

CONCLUSIONS

Our results show that, compared with nondeprived subjects, individuals experiencing social deprivation have a higher risk of unknown nephropathy at dialysis initiation. However, mediation analysis did not identify any variables that explained the association between social deprivation and nephropathy of unknown origin.

Association of circulating proprotein convertase subtilisin/kexin type 9 concentration with coagulation abnormalities in patients with primary membranous nephropathy

OBJECTIVES

The aims of the study were to explore the potential associations between plasma proprotein convertase subtilisin/kexin type 9 (PCSK9) and coagulation indexes in patients with primary membranous nephropathy (PMN).

METHODS

A total of 87 patients diagnosed with PMN were enrolled in our study. 30 healthy participants were recruited to match PMN participants. Plasma PCSK9 concentrations were tested by enzyme-linked immunosorbent assay (ELISA). Correlations between PCSK9 and coagulation abnormalities in patients with PMN were analyzed using univariate and multiple linear regression analysis.

RESULTS

Plasma PCSK9 levels in patients with PMN were significantly higher than that in healthy controls [232.0 (143.5, 359.5) ng/mL vs. 166.8 (129.7, 199.7) ng/mL; p = 0.001]. Plasma levels of PCSK9 were positively correlated with factor VIII, factor IX, factor XI, log-transformed tissue factor, protein C and protein S (r = 0.267, p = 0.013; r = 0.496, p < 0.001; r = 0.217, p = 0.045; r = 0.584, p < 0.001; r = 0.372, p = 0.001; r = 0.282, p = 0.011). In multiple linear regression analysis, PCSK9 concentration was independently and positively correlated with factor VIII, factor IX, and tissue factor (β = 0.186, p = 0.047; β = 0.325, p = 0.001; β = 0.531, p < 0.001; respectively). PCSK9 concentration was independently and negatively correlated with PT (β= -0.343, p = 0.011).

CONCLUSION

Plasma PCSK9 levels had good positive correlations with procoagulant clotting factors and negative correlations with PT in PMN, which might provide novel information with regard to PCSK9 and hypercoagulability in PMN.

HBx-induced PLA2R overexpression mediates podocyte pyroptosis through the ROS-NLRP3 signaling pathway

INTRODUCTION

Hepatitis B virus-associated glomerulonephritis (HBV-GN) is one of the main types of secondary glomerular diseases, and podocyte injury is an important pathogenic mechanism of HBV-GN, participating in the occurrence and development of HBV-GN. However, the specific mechanism of podocyte injury remains to be studied.

METHODS

Human renal podocytes cultured in vitro were divided into six groups. The podocyte morphology was observed under a transmission electron microscope, and the expression of M-type phospholipase A₂ receptor (M-PLA₂R) on the podocyte membrane was observed by indirect immunofluorescence staining under a fluorescence microscope. The pyroptosis rate and reactive oxygen species (ROS) of podocytes were assessed by FLICA/PI double staining and flow cytometry. Western blot (WB) and quantitative real-time PCR (qPCR) were used to determine the expression of PLA₂R, nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing card (ASC), caspase-1, IL-1β, and IL-18.

RESULTS

Hepatitis B virus X (HBx) transfected into human renal podocytes in vitro induced the overexpression of PLA₂R. Moreover, the overexpressed PLA₂R combined with secretory phospholipase A₂ group IB (sPLA₂-IB) aggravated podocyte injury and increased the pyroptosis rate. In addition, the expression of ROS, the NLRP3 inflammasome and downstream inflammatory factors was increased. In contrast, after inhibiting the expression of PLA₂R and ROS, podocyte damage was alleviated, and the pyroptosis rate and the expression of genes related to the ROS-NLRP3 signaling pathway were decreased.

CONCLUSION

HBx-induced PLA₂R overexpression on the podocyte membrane can significantly upregulate the ROS-NLRP3 signaling pathway, thereby mediating podocyte pyroptosis.

[Effect of Short-Term Exposure to Air Pollutants on Hospital Admissions for End-Stage Renal Disease Patients Undergoing Hemodialysis]

Objective

To evaluate the association between short-term exposure to air pollutants of end-stage renal disease (ESRD) patients on maintenance hemodialysis and the number of daily hospital admissions.

Methods

The data on hospitalizations were obtained from the database of the municipal Urban Employees' Basic Medical Insurance and Urban Residents' Basic Medical Insurance of a city in Southwest China. Single and multiple pollutant generalized additive models were utilized to estimate the effect of air pollutants (CO, NO2, O3, PM10, PM2.5, and SO2) on patient admissions after the lag time of different numbers of days. In addition, subgroup analyses stratified by sex, age, PM2.5 and PM10 concentration thresholds, seasonality, and comorbidity status for cardiovascular diseases and hypertension were conducted.

Results

In the single pollutant models, the pollutants significantly associated with patient admissions and the corresponding lag time of the strongest association were as follows, every time CO increased by 0.1 mg/m3, there was a 2.39% increase (95% confidence interval [CI]: 0.96%-3.83%) in patient admissions after 7 days of lag time; every time NO2, O3, PM2.5, PM10, and SO2 increased by 10 μg/m3, patient admissions increased by 4.02% (95% CI: 1.21%-6.91%) after 7 days of lag time, 3.57% (95% CI: 0.78%-6.44%) after 0-4 days of lag time, 2.00% (95% CI: 1.07%-2.93%) after 6 days of lag time, 1.19% (95% CI: 0.51%-1.88%) after 7 days of lag time, and 8.37% (95% CI: 3.08%-13.93%) after 7 days of lag time, respectively. In the multiple pollutant model, every time O3 and PM2.5 increased by 10 μg/m3, there was an increase of 3.18% (95% CI: 0.34%-6.09%) in daily patient admissions after 0-4 days of lag time and an increase of 1.85% (95% CI: 0.44%-3.28%) after 7 days of lag time. Furthermore, subgroup analyses showed that seasonality, the severity of air pollution, and patients' comorbidities might be the effect modifiers for the association between ambient air pollution and hospital admissions in ESRD patients receiving maintenance hemodialysis.

Conclusion

Air pollution is closely associated with hospital admissions in ESRD patients undergoing maintenance hemodialysis and the strength of this association varies according to seasonality, the severity of air pollution, and patients' status of comorbidities.