Gender-related differences in clinicopathological characteristics and renal outcomes of Chinese patients with IgA nephropathy

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.

Mechanisms and consequences of sex differences in immune responses

Biological sex differences refer to differences between males and females caused by the sex chromosome complement (that is, XY or XX), reproductive tissues (that is, the presence of testes or ovaries), and concentrations of sex steroids (that is, testosterone or oestrogens and progesterone). Although these sex differences are binary for most human individuals and mice, transgender individuals receiving hormone therapy, individuals with genetic syndromes (for example, Klinefelter and Turner syndromes) and people with disorders of sexual development reflect the diversity in sex-based biology. The broad distribution of sex steroid hormone receptors across diverse cell types and the differential expression of X-linked and autosomal genes means that sex is a biological variable that can affect the function of all physiological systems, including the immune system. Sex differences in immune cell function and immune responses to foreign and self antigens affect the development and outcome of diverse diseases and immune responses.

Ethnicity and IgA nephropathy: worldwide differences in epidemiology, timing of diagnosis, clinical manifestations, management and prognosis

Immunoglobulin A nephropathy (IgAN), the most common primary glomerulonephritis, is one of the major causes of end-stage renal disease. Significant variances in epidemiology, clinical manifestation, timing of diagnosis, management and renal prognosis of IgAN have been reported worldwide. The incidence of IgAN is the most frequent in Asia, followed by Europe, and lower in Africa. Moreover, Asian patients show more frequent acute lesions in renal histology and present poorer renal outcomes compared with Caucasians. The comorbidities also show the difference between Asians and Caucasians. Although the frequency of gross hematuria with upper respiratory tract infection is not different, comorbidities with gastrointestinal diseases are reported to be higher in Europe. Recently, genetic studies for variant ethnic patients revealed widely ranging genetic risks in each ethnicity. A genetic risk score is most elevated in Asians, intermediate in Europeans and lowest in Africans, consistent with the disease prevalence of IgAN globally. Ethnic variance might be highly affected by the difference in genetic background. However, it is also essential to mention that the different timing of diagnosis due to variant urinary screening systems and the indication for renal biopsy in different countries may also contribute to these variances. The management of IgAN also varies internationally. Currently, several novel therapies based on the pathogenesis of IgAN are being assessed and are expected to become available soon. Further understanding the ethnic variance of IgAN might help establish individualized care for this disease. Here, we review the issues of ethnic heterogeneities of IgAN.

Gender Disparities in Nephrology Trials: A Meta-Analysis of Enrollment Trends between 2000 and 2021

Key Points

Women are under-represented in high-impact nephrology trials. Trends remain consistent over the past 20 years and on the basis of target condition. Addressing the imbalanced enrollment of women in trials could improve disparities in care and outcomes of kidney disease.

Background

Gender disparities in the incidence and complications of kidney diseases are well described. However, analysis to elucidate gender disparities in enrollment in nephrology randomized clinical trials (RCTs) has not been performed.

Methods

We performed a systematic review and meta-analysis of high-impact nephrology RCTs published between 2000 and 2021. We included RCTs enrolling participants aged 18 years and older in the following categories: (1 ) CKD, (2 ) AKI, (3 ) GN, (4 ) maintenance dialysis, and (5 ) kidney transplantation. We summarized trial characteristics according to reporting and enrollment of participants, enrollment site, publication year, trial category, and intervention type. Outcomes of interest include the proportion of enrolled male and female participants overall and according to trial category. In addition, we compared enrollment trends in the United States and globally to estimates of kidney disease prevalence.

Results

Most qualifying trials (373/380, 98%) reported the distribution of male and female participants. Enrollment was imbalanced overall with male participants accounting for 62% (n =215,850) of the enrolled participants and female participants for just 38% (n =133,082). Male participants formed most of trial cohorts in AKI (65%), CKD (62%), dialysis (55%), and transplant trials (65%), whereas women were majority enrollees in GN trials (61%). CKD trials under-represented women in both US trials and worldwide.

Conclusions

Women are under-represented in high-impact nephrology trials with the exception of GN trials. This imbalance may contribute to disparities in outcomes and gaps in the care of women with kidney disease.

Associations of corticosteroid therapy and tonsillectomy with kidney survival in a multicenter prospective study for IgA nephropathy

Efficacy of systemic corticosteroid therapy (CS) for long-term kidney survival in patients with IgA nephropathy (IgAN) is controversial. Therefore, prospective studies evaluating targeted therapies to lymphatic tissues in mucosal immune system responsible for production of nephritogenic IgA have been desired worldwide. Here, we aimed to evaluate the associations of CS and combination therapy of CS and tonsillectomy (CS + Tx) with kidney survival, using database from a nationwide multicenter prospective cohort study on IgAN. Primary outcome was a 50% increase in serum creatinine from baseline or dialysis induction. The analysis included 941 patients (CS/CS + Tx/non-CS 239/364/338), 85 (9.0%) of whom reached outcomes during median follow-up of 5.5 (interquartile range 2.0-8.0) years. On overlap weighting analysis with balanced baseline characteristics, CS and CS + Tx were associated with lower risk of kidney events when compared with non-CS (hazard ratio [HR] 0.51, 95% confidence interval [CI] 0.29-0.88 and HR 0.20, 95%CI 0.09-0.44, respectively). Notably, when compared with the CS, CS + Tx was associated with a lower risk of kidney events (HR 0.40, 95%CI 0.18-0.91). Present study demonstrated, keeping with favorable association of systemic CS with kidney survival, concurrent tonsillectomy as one of targeted interventions to lymphatic tissues may provide additional improvement to kidney survival in patients with IgAN.

Clinicopathological characteristics and associated factors of idiopathic membranous nephropathy with hyperuricemia: a single-centered cross-sectional study

PURPOSE

This study was designed to investigate the clinicopathological features of idiopathic membranous nephropathy (IMN) with hyperuricemia (HUA), together with associated factors within 10 years in a single centre in Shandong Province.

METHODS

In this cross-sectional study, we analysed the clinical and pathological data of 694 IMN patients in our hospital from January 2010 to December 2019. Based on serum uric acid (UA) level, the patients were divided into hyperuricemia (HUA) group (n = 213) and normal serum uric acid (NUA) group (n = 481). Multi-variate logistic regression analysis was conducted on to screen the associated factors of HUA.

RESULTS

213 (30.69%) IMN patient were complicated with HUA. Compared with the patients with NUA, significant increase was noticed in the proportion of patients showing edema, concurrent hypertensive disease or diabetes mellitus (DM), as well as the proportion of positive glomerular capillary loop IgM and positive C1q in the HUA group (P < 0.05). In addition, significant increase was noticed in the 24 h urine protein, serum creatinine, triglycerides, complement C3 and complement C4 in HUA group compared with those of NUA group (all P < 0.05). With gender as a control factor, multi-variate logistic regression analysis showed positive glomerular capillary loops C1q, serum albumin, serum phosphorus were associated with IMN combined with HUA in male, while triglycerides and serum creatinine were associated with IMN combined with HUA in female counterparts.

CONCLUSION

About 30.69% of IMN patients had HUA, with a male predominance than female. In male patients with IMN, higher serum albumin level and serum phosphorus level were associated with higher incidence of HUA, while in female IMN patients, higher serum triglyceridemia and serum creatinine level were associated with higher incidence of HUA. Therefore, it can be targeted to prevent the occurrence of HUA in IMN.

Gender and Liver Steatosis Discriminate Different Physiological Patterns in Obese Patients Undergoing Bariatric Surgery: Obesity Center Cohort

BACKGROUND

Obesity is a major public health problem worldwide. Bariatric surgery can reduce body weight, and it is one of the better ways to improve metabolic disease and lifestyle. The aim of this study was to explore a new cohort of patients with obesity and evaluate the gender differences and the steatosis status within the gender group.

METHODS

A cohort of 250 adult obese patients with BMI ≥ 30 and age >18 years, eligible for gastric bariatric surgery at Pineta Grande Hospital, Castel Volturno (Italy) was studied.

RESULTS

The prevalence in women was higher (72.40%) than men (27.60%). Overall, results indicated many statistically significant gender differences in hematological and clinical parameters. Analysis of the subcohorts based on the severity of steatosis revealed differences of this condition between the genders. Steatosis was more prevalent in the male subcohort, but female patients revealed greater within-group differences.

CONCLUSIONS

Many differences were found not only in the total cohort but also between the gender subcohorts, both in the presence and absence of steatosis. We can conclude that the pathophysiological, genetic, and hormonal patterns affecting these patients delineate different individual profiles.

Role of Sex Hormones in Prevalent Kidney Diseases

Chronic kidney disease (CKD) is a constantly growing global health burden, with more than 840 million people affected worldwide. CKD presents sex disparities in the pathophysiology of the disease, as well as in the epidemiology, clinical manifestations, and disease progression. Overall, while CKD is more frequent in females, males have a higher risk to progress to end-stage kidney disease. In recent years, numerous studies have highlighted the role of sex hormones in the health and diseases of several organs, including the kidney. In this review, we present a clinical overview of the sex-differences in CKD and a selection of prominent kidney diseases causing CKD: lupus nephritis, diabetic kidney disease, IgA nephropathy, and autosomal dominant polycystic kidney disease. We report clinical and experimental findings on the role of sex hormones in the development of the disease and its progression to end-stage kidney disease.

Clinicopathological characteristics and risk factors in elderly patients with biopsy-proven IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) has been well studied among young people, but few data on clinicopathological characteristics, treatment response and outcomes for elderly IgAN patients are available.

METHODS

A cohort study of elderly IgAN patients was performed. The combined endpoints of renal outcome were a 50% decline in eGFR compared with the time of renal biopsy, end-stage kidney disease and/or death. Risk factors associated with poor renal outcomes were then determined. The benefits of immunosuppressant therapies were also evaluated by Kaplan-Meier survival curve analysis.

RESULTS

This study ultimately included 126 elderly patients with IgAN. Comparison between the endpoint and non-endpoint groups indicated that patients with poor outcomes had more severe clinical features, such as worse kidney function, severe hematuria and lower albumin levels. Cox regression analysis indicated that age (HR 1.15, 95% CI 1.02-1.29, p = 0.021), male gender (HR 9.71, 95% CI 1.00-97.56, p = 0.050), and urine red blood cells (HR 1.003, 95% CI 1.000-1.006, p = 0.029) were independent risk factors for poor renal outcome in elderly IgAN patients. To explore possible reasons accounting for the predictive value of age and sex, patients were divided into two groups based on these two variables. Patients in the geriatric group had lower serum albumin, estimated glomerular filtration rate, hemoglobin and aspartate aminotransferase levels than those in the quinquagenarian group. Male patients tended to have higher hemoglobin, higher alanine aminotransferase, and lower triglycerides and cholesterol levels than female patients. To investigate different treatment responses, patients were classified into two groups depending on treatment strategies (renin-angiotensin system inhibitors and immunosuppressive therapy), and the survival analysis indicated no significant difference in kidney outcome between the two groups (p > 0.05). This result still holds after adjusting for age, sex, eGFR, hematuria, and proteinuria.

CONCLUSION

Advanced age, male, and hematuria might be independently associated with poor kidney outcomes in elderly patients with IgAN. Immunosuppressive therapy might confer no overall benefit to older IgAN patients.

Great prognosis of concurrent anti-GBM disease and IgA nephropathy in a young woman: A case report

RATIONALE

The causal relationship between anti-glomerular basement membrane (anti-GBM) disease and immunoglobulin A (IgA) nephropathy is still unclear and cases of concurrent anti-GBM disease and IgA nephropathy are very rare, especially with a good prognosis and long-term follow-up. Here, we report a case of concurrent anti-GBM disease and IgA nephropathy. By using corticosteroids and cyclophosphamide in combination with plasmapheresis, the patient achieved a very good prognosis with complete normalization of renal function and complete disappearance of hematuria and proteinuria at the subsequent follow-up. To our knowledge, no previous case with such a long follow-up and such a good prognosis have been reported.

PATIENT CONCERNS

This case report describes a 26-year-old Chinese woman who presented with fever as the initial symptom, followed by dysmorphic hematuria, overt proteinuria and rapidly worsening renal function. Before admission, the patient received symptomatic supportive treatment such as intravenous albumin infusion, improvement of circulation, but the symptoms were not significantly improved.

DIAGNOSIS

Per the results of kidney biopsy, the patient was diagnosed with crescentic glomerulonephritis and anti-GBM disease with IgA nephropathy.

INTERVENTIONS

The key to obtain a good prognosis was the early application of corticosteroids and cyclophosphamide in combination with plasmapheresis to make the anti-GBM antibody turn negative quickly.

OUTCOMES

After 2 weeks of therapy, the patients' anti-GBM antibody turned negative and serum creatinine improved to a normal range. After 10 months, the patient's proteinuria level reached complete remission. After 12 months, the patient's hematuria had disappeared completely.

LESSONS

This case provides experience in the treatment of concurrent anti-GBM disease and IgA nephropathy and highlights the importance of early application of plasmapheresis and immunosuppressive therapy to obtain a good prognosis.

Left ventricular myocardial mass index associated with cardiovascular and renal prognosis in IgA nephropathy

Introduction

In chronic kidney disease (CKD), like in IgA nephropathy (IgAN), cardiovascular (CV) mortality and morbidity are many times higher than in the general population, and left ventricular hypertrophy (LVH) is an independent risk factor for CV disease. This follow-up study investigated the association between left ventricular mass index (LVMI) and renal or cardiovascular outcomes.

Methods

We examined 118 IgAN patients prospectively. LVMI and LV geometry was investigated using echocardiography. The primary combined endpoints were total mortality, major CV events, and end-stage renal disease. Secondary endpoints, i.e.—cardiovascular or renal endpoints,—were also examined separately.

Results

Sixty seven percent were males, mean age 53.5 ± 13.5. Mean follow-up time: 184 months. LVMI inversely correlated with eGFR (corr. coefficient: -0.365; p < 0.01). We divided the patients into two groups based on the LVMI cut-off suggested by the literature. The presence of LVH caused a worse prognosis in primary (p < 0.001), renal endpoints (p = 0.01), and also in CV endpoints (p = 0.001). The higher LVMI in men significantly worsened the prognosis in all endpoints. Concentric hypertrophy meant a worse prognosis. Independent predictors of LVMI were gender and eGFR in uni- and multivariate regression and hemoglobin levels only in logistic regression. Independent predictors of the primary endpoint were LVMI, eGFR, gender, obesity, HT, DM, and metabolic syndrome in Cox regression analysis.

Conclusion

Increased LVMI may predict the progression to end-stage renal disease and CV events in IgAN. Determining LVMI may be a useful parameter not only in CV risk but also in the stratification of renal risk in CKD.

Does Gender Affirming Hormone Therapy Increase the Risk of Kidney Disease?

Kidney health and manifestation of disease in transgender men, women, and nonbinary individuals are not well understood. Transgender individuals commonly receive gender-affirming hormone therapy (GAHT) to align their outward appearance with their gender. Recent attention to the differences in fundamental kidney parameters has identified that transgender individuals may manifest levels of these biomarkers differently than their cisgender counterparts. Improving understanding of the differences in biomarkers and in the development of kidney disease is essential to providing appropriate kidney care to this vulnerable population. In this review, we introduce the current information related to GAHT and kidney health and highlight the significant gaps in our understanding of how GAHT may affect kidney physiology and pathophysiology.

Sex and Gender in Glomerular Disease

There is increasing understanding that a multifaceted interplay of sex-dependent genetic and immune dysregulation underpins the development of glomerular disorders. Regional and ethnic variations in glomerular disease incidence make delineating the effects of sex and gender on disease pathophysiology more complex, but there is a marked paucity of research in this area. This review article presents a summary of the current understanding of sex and gender in glomerular disease, highlighting the broader effects of sex and gender on autoimmunity, clinical presentations, and pathophysiology of individual glomerular diseases, as well as exploring sex, gender, and glomerular disease within a wider socioenvironmental context. It is important to specifically consider the effects of sex and gender when presenting and analyzing clinical and scientific studies on glomerular disease. Failure to do so risks promoting disparities within health care provision, neglecting opportunities to identify sex-specific biomarkers, and potentially hindering the development of sex-specific therapies.

Incidence, demographic, biochemical, and clinicopathological profile of primary IgAN in a tertiary care center from Northern India

Background

Primary IgA nephropathy (IgAN) has variable distribution and clinicopathological spectrum throughout the world. We report the incidence, demographic, and clinicopathological profile of primary IgAN from a tertiary care center in Northern India.

Methods

This is a single-center, prospective, observational study conducted at Sheri- Kashmir Institute of Medical Sciences, J&K, India, from January 2015 to December 2018. The study was approved by the hospital ethical committee.

Results

A total of 106 patients were included in this study, accounting for 19% (106/558) of all native kidney biopsies done during the period from January 2015 till December 2018. Males and females accounted for 60.4% (64/106) and 39.6% (42/106), respectively, with a ratio of 1.5:1. The mean age was 31.37±11.60 years. Edema and hypertension were the most common presenting symptoms and signs, seen in 69 (65.1%) and 72 (67.9%) patients, respectively. The baseline 24-h urine protein excretion was 2.32 ±1.34 g, Nephrotic range proteinuria (≥3.5g/day) was seen in 23/106 (21.7%). Average serum creatinine was 1.6±0.80 mg/dl and estimated glomerular filtration rate using CKD-EPI was <60 ml/min/1.73 m2 in 48.1% of patients (51/106). In patients with < 1 g proteinuria, 36.8% had E1, 78.9% had S1, 36.8% had T1, and 42.1% had T2 lesions.

Conclusions

IgAN is common in North India and has a more severe histopathological presentation, characterized by extensive sclerosis and tubulointerstitial fibrosis. Renal dysfunction and nephrotic range proteinuria are common. Hypertension, low eGFR, and proteinuria correlate with the presence of segmental scarring, endocapillary hypercellularity, and IFTA. Screening of asymptomatic individuals might help in early diagnosis and long-term preservation of renal function.

Immunoglobulin A (IgA) Nephropathy: A Clinicopathologic Study in a Tertiary Care Center in Saudi Arabia

Background: Immunoglobulin A nephropathy (IgAN) is the most common primary aetiology of glomerulonephritis worldwide, and it is the most important type in terms of morbidity and mortality. IgAN involves the deposition of immune bodies in the mesangial cells of the kidney, which causes renal glomerular damage, haematuria, proteinuria, and various other symptoms. Previous studies have mainly focused on the East Asian population, with few studies conducted in Saudi Arabia, particularly in the western region. The diagnosis requires a biopsy, which should be examined by an expert and classified according to the Oxford classification system.

Objectives: Analyze the clinical, pathological, and laboratory features of male and female patients diagnosed with IgAN at King Abdulaziz University Hospital (KAUH).

Methods and materials: This was a retrospective record review conducted at KAUH in Jeddah, Saudi Arabia between May-June 2021. The study included 18 patients diagnosed with IgAN by biopsy, and their clinical, laboratory and pathological data were evaluated and classified according to the Oxford classification system.

Results: Demographic data revealed a male predominance of 66.7%. The most common pathological finding was mesangial proliferation, and the most common presentation was haematuria. For treatment options, corticosteroids were the most prescribed drugs. A significant relationship was found between IgAN with increased serum creatinine and male sex (P = 0.017). Additionally, a significant relationship was observed between decreased estimated glomerular filtration rate (eGFR) in IgAN and the male sex (P = 0.006).

Conclusions: We found a difference in terms of pathological, clinical and laboratory presentations of IgAN between males and females. Men generally had worse kidney function at presentation and advanced Oxford classification in their kidney biopsies compared to women.

Association between urinary VEGFA and renal pathology of IgA nephropathy patients

BACKGROUND

Renal biopsy remains the golden standard for diagnosing and monitoring IgA nephropathy (IgAN). Vascular endothelial growth factor A (VEGFA) was crucial for the survival of glomerular cells. Our aim was to screen the expression pattern of urinary, circulating and renal VEGFA in IgAN patients to reveal their relationship with renal pathology and outcomes.

METHODS

Baseline VEGFA levels were determined with ELISA, real-time PCR and immunohistochemistry. Associations between VEGFA expression and clinical-pathological parameters, and renal outcomes were evaluated.

RESULTS

Compared with healthy controls, urinary VEGFA level was obviously elevated in IgAN patients (76.19 ± 63.67 pg/mg Cr vs 146.67 ± 232.71 pg/mg Cr, p = 0.0291) and not correlated with serum VEGFA level. Baseline urinary VEGFA was significantly associated with gender and tubular atrophy/interstitial fibrosis by stepwise multivariate regression analysis. Urinary VEGFA was higher in male patients accompanied with higher serum creatinine, larger proportion of hypertension and recurrent hematuria than in female patients. In the kidney of IgAN patients, VEGFA were robustly expressed in the parietal epithelial cells, podocytes, mesangial cells and tubular epithelial cells. After a follow-up duration of 38.53 ± 27.14 months, IgAN patients with higher urinary VEGFA level were found to have a poorer renal outcome of renal replacement therapy (HR = 1.027, p = 0.037) or composite outcome (HR = 1.023, p = 0.039) after adjusting for confounders.

CONCLUSIONS

Increased urinary VEGFA might reflect certain renal pathology and, although not fully specific, still could be served as a valuable noninvasive indicator in predicting renal progression of IgAN.

Urinary exosomal circular RNAs of sex chromosome origin are associated with gender-related risk differences of clinicopathological features in patients with IgA nephropathy

BACKGROUND

There are arguments for individualized treatments and the necessity of non-invasive biomarkers for patients with IgA nephropathy (IgAN) according to gender, but the rationale remains unclear. We aimed to investigate the relationship between urine exosomal circular RNA (circRNA) levels, related genes, clinical features, and renal pathological features in IgA nephropathy patients of different genders.

METHODS

Clinicopathological data from patients of different genders from a multicenter cohort were retrospectively analyzed. We used the Oxford classification to examine the severity of pathological damage in these patients. We compared clinical features and renal pathologies between IgAN patients of different genders. Using findings of urine exosomal circRNAs from male IgAN patients, we analyzed the relationship between this factor, the regulated genes located on the sex chromosomes, and renal pathologies.

RESULTS

A total of 502 IgAN patients were included. The proportion of male patients with crescent formation was higher than that of females (p = 0.019). Multivariate logistic regression analysis showed that proteinuria was an independent marker for crescent formation in male and female patients with IgAN, while smoking and higher low-density lipoprotein cholesterol (LDL-C) levels were independent risk factors for crescent formation in males alone. Urine exosomal circRNA chrY:15478147-15481229- located on the Y chromosome in male patients was negatively correlated with the expressions of UTY in specific regions of the Y chromosome.

CONCLUSION

Compared with female patients, males with IgAN had more severe renal dysfunction and a higher probability of glomerular crescent formation. Urine exosomal circRNA chrY:15478147-15481229- might participate in the pathogenesis of IgAN in male patients by altering UTY expressions.

Sex Differences in Renal Function: Participation of Gonadal Hormones and Prolactin

Kidney pathophysiology is influenced by gender. Evidence suggests that kidney damage is more severe in males than in females and that sexual hormones contribute to this. Elevated prolactin concentration is common in renal impairment patients and is associated with an unfavorable prognosis. However, PRL is involved in the osmoregulatory process and promotes endothelial proliferation, dilatation, and permeability in blood vessels. Several proteinases cleavage its structure, forming vasoinhibins. These fragments have antagonistic PRL effects on endothelium and might be associated with renal endothelial dysfunction, but its role in the kidneys has not been enough investigated. Therefore, the purpose of this review is to describe the influence of sexual dimorphism and gonadal hormones on kidney damage, emphasizing the role of the hormone prolactin and its cleavage products, the vasoinhibins.

The Phenotypic Difference of IgA Nephropathy and its Race/Gender-dependent Molecular Mechanisms

IgA nephropathy (IgAn), defined by the pre dominant de position of IgA in the glomerular mesangium, is the most common form of GN throughout the world. However, its incidence, sex distribution, clinical presentation, and progression and pathogenic initiating factors are largely variable and do not fit such a simple definition. To assess the heterogeneity of this disease, we recently conducted a clinical survey on the presentation and clinical management of patients with IgAn in Europe and Japan. This clinical survey highlights similarities and differences in patients from different cont inents. The survey revealed obvious differences between nations in the frequency of gastrointestinal complications, including inflammatory bowel diseases (IBD) and celiac disease, which were more frequent in European patients. Such findings are compatible with susceptibility loci related to intestinal immunity and IBD in recent genome wide association studies (GWAS) on IgAn. However, most of the molecules in these mucosal-related loci fulfill the immunologic function not only of gut-associated lymphoid tissue (GALT), but also nasopharyngeal/bronchial-associated lymphoid tissues (NALT/BALT). Indeed, a similar frequency of macrohematuria coinciding with upper respiratory infection, a hallmark manifestation of this disease, was found in the survey, emphasizing the pathogenic roles of these molecules in the NALT/BALT of patients with IgAn. Recent experimental and clinical studies including GWAS on multiple common infections and IBD indicate immune crosstalk between GALT and NALT/BALT, and some related mediators, such as TNF superfamily ligands (APRIL/BAFF). This review explains the epidemiologic heterogeneity of this disease with the clinical survey, and discusses race and sex-dependent molecular mechanisms.

Gut microbiota in Immunoglobulin A Nephropathy: a Malaysian Perspective

INTRODUCTION

The alteration of the gut microbiome in the gut-kidney axis has been associated with a pro-inflammatory state and chronic kidney disease (CKD). A small-scaled Italian study has shown an association between the gut microbiome and Immunoglobulin A Nephropathy (IgAN). However, there is no data on gut microbiota in IgAN in the Asian population. This study compares the gut microbial abundance and diversity between healthy volunteers and Malaysian IgAN cohort.

METHODS

A comparative cross-sectional study was conducted involving biopsy-proven IgAN patients in clinical remission with matched controls in a Malaysian tertiary centre. Demographic data, routine blood and urine results were recorded. Stool samples were collected and their DNA was extracted by 16S rRNA gene sequencing to profile their gut microbiota.

RESULTS

Thirty-six IgAN patients (13 male; 23 female) with the mean age of 45.5 ± 13.4 years and median estimated glomerular filtration rate (eGFR) of 79.0 (62.1-92.2) mls/min/1.73m² with median remission of 7 years were analysed and compared with 12 healthy controls (4 male; 8 female) with the mean age of 46.5 ± 13.5 years and eGFR of 86.5 (74.2-93.7) mls/min/1.73m². Other demographic and laboratory parameters such as gender, ethnicity, body mass index (BMI), haemoglobin, serum urea and serum albumin were comparable between the two groups. There were no significant differences seen in the Operational Taxonomic Unit (OTU) and alpha diversity (Shannon index) between IgAN and healthy controls. Alpha diversity increased with increasing CKD stage (p = 0.025). Firmicutes/Bacteroidetes (F/B) ratio was low in both IgAN and healthy cohort. Fusobacteria phylum was significantly increased (p = 0.005) whereas Euryarchaoeota phylum was reduced (p = 0.016) in the IgAN group as compared to the control cohort.

CONCLUSION

Although we found no differences in OTU and alpha diversity between IgAN in remission and control cohort, there were some differences between the two groups at phylum level.

Epidemiology, baseline characteristics and risk of progression in the first South-Asian prospective longitudinal observational IgA nephropathy cohort

INTRODUCTION

Glomerular Research And Clinical Experiments-IgA Nephropathy in Indians (GRACE-IgANI) is the first prospective South Asian IgAN cohort with protocolized follow-up and extensive biosample collection. Here we report the baseline clinical, biochemical, and histopathologic characteristics of GRACE IgANI and calculate baseline risk of progression for the cohort.

METHODS

201 incident adults with kidney biopsy-proven primary IgAN were recruited into GRACE-IgANI between March 2015 and September 2017. As of April 30, 2020, the cohort had completed a median follow-up of 30 months (interquartile range [IQR] 16-39).

RESULTS

The commonest clinical presentation in GRACE IgANI was hypertension, with or without proteinuria, and nephrotic-range proteinuria was present in 34%, despite <10 months of lead time to kidney biopsy. The GRACE-IgANI kidney biopsy data demonstrated a disproportionate absence of active glomerular lesions and overrepresentation of segmental sclerosing lesions and tubulointerstitial fibrosis at presentation, often coexistent with relatively well-preserved estimated glomerular filtration rate (eGFR) and low levels of proteinuria, especially in males. Baseline risk of progression was calculated for each evaluable patient using 2 different risk prediction tools. The median 5-year absolute risk of end-stage kidney disease (ESKD) was 19.8% (IQR 2.7-57.4) and median 5-year risk of progression to the combined endpoint of 50% decline in eGFR or ESKD was 35.5% using the 2 tools.

CONCLUSIONS

The predicted risk of progression in this cohort was considerable. Over the next 5 years, we will dissect the pathogenic pathways that underlie this severe South Asian IgAN phenotype.

Estrogen and estrogen receptors in kidney diseases

Acute kidney injury (AKI) and chronic kidney disease (CKD) are posing great threats to global health within this century. Studies have suggested that estrogen and estrogen receptors (ERs) play important roles in many physiological processes in the kidney. For instance, they are crucial in maintaining mitochondrial homeostasis and modulating endothelin-1 (ET-1) system in the kidney. Estrogen takes part in the kidney repair and regeneration via its receptors. Estrogen also participates in the regulation of phosphorus homeostasis via its receptors in the proximal tubule. The ERα polymorphisms have been associated with the susceptibilities and outcomes of several renal diseases. As a consequence, the altered or dysregulated estrogen/ERs signaling pathways may contribute to a variety of kidney diseases, including various causes-induced AKI, diabetic kidney disease (DKD), lupus nephritis (LN), IgA nephropathy (IgAN), CKD complications, etc. Experimental and clinical studies have shown that targeting estrogen/ERs signaling pathways might have protective effects against certain renal disorders. However, many unsolved problems still exist in knowledge regarding the roles of estrogen and ERs in distinct kidney diseases. Further research is needed to shed light on this area and to enable the discovery of pathway-specific therapies for kidney diseases.

Sex disparities in IgA nephropathy: a retrospective study in Chinese patients

AIM

The aim of this study was to explore the effect of sex on the clinicopathological features and long-term outcomes of IgAN patients.

METHODS

A total of 1096 adult IgAN patients were divided into male and female groups. Clinicopathological features and risk factors of IgAN patients of different genders were contrasted. The primary endpoint was the combined endpoint of a 50% reduction in estimated glomerular filtration rate (eGFR) and/or end stage renal disease (ESRD: eGFR < 15 mL/min/1.73 m² or dialysis). The effect of gender on prognosis of IgAN was assessed using Kaplan-Meier and Cox proportional hazards models.

RESULTS

In total, 475 male patients and 621 female patients were included in this study. At baseline, male patients had higher values for blood pressure, serum creatinine, urine protein and serum uric acid, as well as lower levels of eGFR. Further analysis indicated that tubular atrophy/interstitial fibrosis (T) lesions and vascular lesions were more frequent in male patients. During the follow-up period of 40.9 ± 24.2 months, kidney survival rates of male IgAN patients were remarkably lower than those of female patients. Using multivariate Cox regression analysis, male gender was identified as an independent risk factor for poor outcomes (β = 0.384, Wald = 4.290, Exp (β) = 1.47, p = 0.038), including hypertension, low eGFR, IgM deposition, arteriosclerosis lesions and T1-T2 lesions. However, male and female patients were characterized by different risk factors.

CONCLUSION

Male patients presented with more severe clinical and pathological changes than female patients. Renal survival rates of male patients were remarkably lower than those of female patients, and male gender was identified as an independent risk factor for poor outcomes.

Gender-specific association between uric acid level and chronic kidney disease in the elderly health checkup population in China

Objective: To evaluate the association between serum uric acid (SUA) levels with CKD in elderly health checkup population and explore the gender difference.

Methods: A total of 4242 subjects were included in the cross-sectional study. All of the subjects participated in the annual checkup between June 2016 and June 2017. Chronic kidney disease (CKD) was defined by estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m². We examined the association between SUA levels and CKD. Multivariate binary logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) by comparing association between the SUA level and CKD. The models were adjusted for age, gender, body mass index (BMI), hypertension, diabetes, triglyceride and high-density lipoprotein cholesterol (HDL-C).

Result: The prevalence of hyperuricemia was 22.2%, and it was significantly higher in male than in female (25.2% vs. 17%, p < .001). The prevalence of hyperuricemia increased with age, especially in the female. The prevalence of CKD was 27.8% in male and 20.2% in female (p < .001). Compared with the SUA first quartile, the multivariate-adjusted odds for CKD of fourth quartiles were 6.05 (95%CI: 4.32–8.49) in male and 8.21(95%CI: 5.37–12.54) in female.

Conclusion: Our finding showed gender-specific differences in the association between high SUA and an increased risk of CKD in the elderly population. The association of SUA and CKD was independent of other potential confounding factors including age, glucose, hypertension, HDL, TG and BMI.