Pathological spectrum of glomerular disease in patients with renal insufficiency: a single-center study in Northeastern 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.

Review on epidemiology, disease burden, and treatment patterns of IgA nephropathy in select APAC countries

BACKGROUND

Immunoglobulin type A (IgA) nephropathy is the most common primary glomerulonephritis (GN) worldwide with higher rates in East and Pacific Asia compared to North America and Europe. Despite high reported prevalence of IgAN in these countries, the overall disease prevalence across Asia is not available. Treatment patterns of IgAN patients across Asian countries have also not been summarized. The aim of this study was to review and summarize evidence on IgA nephropathy prevalence, treatment patterns, and humanistic and economic burden in mainland China, Taiwan, South Korea, Japan, and Australia.

METHODS

A targeted literature review was conducted in PubMed and local databases in China (including Taiwan), South Korea, Japan, and Australia between January 2010-December 2021. Website literature searches were conducted using Google Scholar and Baidu.

RESULTS

Sixty-nine publications and 3 clinical guidelines were included. Incidence ranged from 0 to 10.7 per 100 000 people per year in Australia, Japan, and Taiwan, and ranged from 6.3 to 24.70% among patients who underwent renal biopsy in mainland China. Prevalence and diagnosis rates ranged from 0 to 72.1% in mainland China, South Korea, Taiwan, Japan, and Australia. Mortality rates in mainland China, South Korea, and Japan varied widely. The top 3 commonly used therapies were angiotensin-converting enzyme inhibitor/angiotensin receptor blockers (0.9-99.6%), corticosteroids (3.5-100%), and immunosuppressants (1.6-85.5%) in Japan, mainland China, and South Korea. Patient quality of life was measured by different tools, and annual hospitalization costs ranged from $1 284.73 to $2 252.12 (2015-2018) in China.

CONCLUSIONS

The prevalence of IgA nephropathy among the general population in select countries/regions is not commonly available, despite evidence from studies and clinical guidelines. In addition, it is observed across geographic regions that heterogeneity exists in prevalence rates, and large variations exist in treatment patterns. There is need to fill in these gaps to understand the contributing factors behind the differences through population-based, multi-center, and real-world studies.

Renal function in aged C57BL/6J mice is impaired by deposition of age-related apolipoprotein A-II amyloid independent of kidney aging

Spontaneous and age-related amyloidosis has been reported in C57BL/6J mice; however, the biochemical characteristics of age-related amyloidosis remain unclear. Therefore, we herein investigated the age-related prevalence of amyloidosis, the types of amyloid fibril proteins, and the effects of amyloid deposition on renal function in C57BL/6J mice. The results obtained revealed a high incidence of amyloidosis in C57BL/6J mice originating from the Jackson laboratory as well as the deposition of large amounts of amyloid in the glomeruli of aged mice. We identified the amyloid fibril protein in C57BL/6J mice as wild-type apolipoprotein A-II. We induced renal amyloid deposition in 40-week-old mice, equivalent to that of spontaneous development in 80-week-old mice, to rule out the effects of aging, and revealed subsequent damage to kidney function by amyloid deposits. Furthermore, amyloid deposition in the mesangial region decreased podocyte density, compromised foot processes, and led to the accumulation of fibroblast growth factor 2 (FGF2) in glomeruli. Collectively, these results suggest that AApoAII deposition is a general pathology in aged C57BL/6J mice and is dependent on supplier colonies. Therefore, the effects of age-related amyloid deposition need to be considered in research on aging in mice.

Distribution of pathological types and epidemiological characteristics based on kidney biopsy in Northwest China

BACKGROUND

The spectrum of biopsy-confirmed kidney disease varies with regions and periods. We describe the distribution of pathological types and epidemiological characteristics of kidney diseases in Northwest China due to regional differences in geographical environment, social economy, and dietary habits.

METHODS

Kidney biopsy cases from 2005 to 2020 in Xijing Hospital were retrospectively analyzed. Pathological characteristics of patients in different periods were analyzed using the t test or chi-square test. Joinpoint regression was used to analyze trends in pathological types and disease spectrum.

RESULTS

A total of 10,528 eligible patients were included. Primary glomerular disease (PGD) accounted for the majority of the cases and exhibited an obvious downward trend, whereas secondary glomerular disease (SGD) showed an obvious upward trend. Among PGD, immunoglobulin A nephropathy (IgAN) remained the most common pathological type, and the detection rate of membranous nephropathy (MN) was significantly increased. Among SGD, Henoch-Schönlein purpura nephritis (HSPN) was the most common pathological type and may present a significant characteristic of Northwest China. Diabetic nephropathy (DN) exhibited the most obvious upward trend in the whole process, whereas the fastest growth since 2012 was in hypertensive nephropathy.

CONCLUSION

The proportion of SGD increased whereas PGD declined. IgAN remained the most common PGD, and HSPN was the most common SGD. MN and DN showed the most obvious upward trend among PGD and SGD, respectively. Changes in the spectrum of kidney disease, especially the constituent ratio of SGD, pose a great challenge to public health.

Kidney diseases and long non-coding RNAs in the limelight

The most extensively and well-investigated sequences in the human genome are protein-coding genes, while large numbers of non-coding sequences exist in the human body and are even more diverse with more potential roles than coding sequences. With the unveiling of non-coding RNA research, long-stranded non-coding RNAs (lncRNAs), a class of transcripts >200 nucleotides in length primarily expressed in the nucleus and rarely in the cytoplasm, have drawn our attention. LncRNAs are involved in various levels of gene regulatory processes, including but not limited to promoter activity, epigenetics, translation and transcription efficiency, and intracellular transport. They are also dysregulated in various pathophysiological processes, especially in diseases and cancers involving genomic imprinting. In recent years, numerous studies have linked lncRNAs to the pathophysiology of various kidney diseases. This review summarizes the molecular mechanisms involved in lncRNAs, their impact on kidney diseases, and associated complications, as well as the value of lncRNAs as emerging biomarkers for the prevention and prognosis of kidney diseases, suggesting their potential as new therapeutic tools.

Morphological Spectrum of Glomerulonephritis in Medical Renal Biopsies: A Single-Center Study

Background

Glomerulonephritis is among the most common and serious non-communicable diseases in the world, and some of them are major causes of chronic kidney disease, which eventually leads to kidney failure. In developing countries, it is the most common cause of end-stage renal disease (ESRD). Chronic kidney disease affects 10-16% of the adult population in Asia, including 21.2% in Pakistan. This study aims to determine the frequency and spectrum of glomerulonephritis at our center.

Methodology

This is a cross-sectional analysis of 81 renal core biopsies obtained between August 2020 and August 2021. The histopathological reports, demographic data, and relevant laboratory investigations, such as blood urea and creatinine levels, were collected. All cases were blindly reviewed by two pathologists with a special interest in medical renal pathology. Data were analyzed using SPSS version 22 (IBM Corp., Armonk, NY, USA).

Results

The majority of the patients (46.9%) were between the ages of 21 and 40 years. There was a slight male predominance, with 44 (54.3%) of the 81 participants being male. Hematuria was reported in 20 (24.7%) patients, with mean serum urea and creatinine levels of 75 mg/dL and 2.6 mg/dL, respectively. Nephrotic syndrome was the most common indication for a renal biopsy, accounting for 54 (67.7%) of the 81 cases. Chronic glomerulonephritis is classified into two categories, namely, primary and secondary glomerulonephritis. Focal segmental glomerulosclerosis (FSGS), the leading cause of primary glomerulonephritis, was found in 25 (30.9%) 81 patients. Furthermore, lupus nephritis (9.9%) and advanced glomerulonephritis (9.9%) were found in equal proportions among secondary glomerulonephritis.

Conclusions

According to our study, nephrotic syndrome was the most common indication for medical renal biopsy, with FSGS being the most common primary glomerulonephritis. Lupus nephritis and advanced glomerulonephritis were the most common secondary glomerulonephritis diagnoses.

B Cells in Primary Membranous Nephropathy: Escape from Immune Tolerance and Implications for Patient Management

Membranous nephropathy (MN) is an important cause of nephrotic syndrome and chronic kidney disease (CKD) in adults. The pathogenic significance of B cells in MN is increasingly recognized, especially following the discovery of various autoantibodies that target specific podocytic antigens and the promising treatment responses seen with B cell depleting therapies. The presence of autoreactive B cells and autoantibodies that bind to antigens on podocyte surfaces are characteristic features of MN, and are the result of breaches in central and peripheral tolerance of B lymphocytes. These perturbations in B cell tolerance include altered B lymphocyte subsets, dysregulation of genes that govern immunoglobulin production, aberrant somatic hypermutation and co-stimulatory signalling, abnormal expression of B cell-related cytokines, and increased B cell infiltrates and organized tertiary lymphoid structures within the kidneys. An understanding of the role of B cell tolerance and homeostasis may have important implications for patient management in MN, as conventional immunosuppressive treatments and novel B cell-targeted therapies show distinct effects on proliferation, differentiation and reconstitution in different B cell subsets. Circulating B lymphocytes and related cytokines may serve as potential biomarkers for treatment selection, monitoring of therapeutic response and prediction of disease relapse. These recent advances in the understanding of B cell tolerance in MN have provided greater insight into its immunopathogenesis and potential novel strategies for disease monitoring and treatment.

LncRNA PTTG3P induced aberrant glycosylated IgA1 production and B cell growth in IgA nephropathy

Growing evidences suggested that lncRNAs played functional role in several cell functions such as cell growth, invasion, migration, metabolize, apoptosis, and differentiation. However, roles of lncRNA in the development and progression of IgAN remain unknown. In this reference, we indicated that PTTG3P level was overexpressed in IgAN samples compared to healthy subject. PTTG3P expression was also higher in urinary of IgAN cases than in urinary of healthy control. Furthermore, the urinary expression of PTTG3P was correlated with PTTG3P expression in intra-renal of IgAN cases. PTTG3P overexpression induced B cell growth and enhanced cyclin D1 and ki-67 expression. Overexpression of PTTG3P induced IL-1β and IL-8 production. miR-383 level was decreased in IgAN samples compared to healthy subject. In addition, miR-383 expression was also lower in urinary of IgAN cases than in urinary of healthy control. Elevated miR-383 expression decreased luciferase intensity regulated with PTTG3P, while overexpression of miR-383 had no effect on luciferase intensity of the mutant PTTG3P. PTTG3P overexpression suppressed miR-383 expression in B cells. Ectopic miR-383 expression suppressed B cell growth and IL-1β and IL-8 production. Finally, we showed that overexpression of PTTG3P promoted B cell growth and IL-1β and IL-8 production via regulating miR-383. There results proved that PTTG3P played crucial role in progression of IgAN.

A Spectrum of Biopsy - Proven Renal Disorders and Their Clinicopathological Correlation in Elderly Population From a Tertiary Care Center in South India

Introduction

Chronic kidney disease (CKD) has become a health concern with an extensive burden on incidence and prognosis. While the increasing lifespan contributes to a higher incidence of CKD among the elderly, the diagnostic picture in this age group is complicated by senescence-related changes. A better understanding of the etiology and progression of the disease warrants renal biopsy in such patients. This study aims to explore the histopathological spectrum of native renal biopsies leading to CKD in elderly patients in a tertiary care hospital.

Methods

Among the list of patients who had undergone renal biopsy at our institute from January 2015 to March 2020, elderly patients aged ≥ 60years were chosen for this study. Their demographic details, lab investigations and histopathological reports were collected. The sex distribution and prevalence of different renal diseases was calculated. The subjects were classified into four broad diagnostic groups - primary glomerular disease, diabetic nephropathy, hypertensive nephropathy, and tubulointerstitial disease. The estimated glomerular filtration rate (eGFR) values were calculated and used to stage chronic kidney disease in these patients. Statistical analysis was carried out to find a correlation between diagnostic groups and CKD presence and between serum C3 values and immunofluorescence for the same on biopsy.

Results

One hundred thirty-two patients formed the study sample with a male to female ratio of 1.28:1, showing a slight male predominance. The most common diagnostic group was primary glomerular disease (46%), among which focal segmental glomerulosclerosis (FSGS) was the most common entity (12%). 47.7% and 66.6% of patients in the study sample showed elevated serum blood urea nitrogen (BUN) and creatinine values, respectively. 86% of our study sample had low eGFR values, and the majority (35%) of the patients were classified under CKD stage 3. CKD incidence was high among patients with primary glomerular diseases, but no significant statistical correlation was found. 43.5% of all IF positive cases showed low serum C3 values and established a positive correlation between IF and serum C3 values.

Conclusion

There is no statistically significant correlation of the four diagnostic groups to the CKD. CKD in the elderly may be multifactorial, and a collaborative study across the nations may be needed to further evaluate the etiology.

Clinical and pathological analysis of renal biopsies of elderly patients in Northeast China: a single-center study

Purpose

To identify the clinical characteristics, histopathological features, and prognosis of kidney disease in a large cohort of elderly patients from Northeast China.

Methods

We retrospectively analyzed the renal disease spectrum in 7,122 patients who underwent renal biopsies at the Second Hospital of Jilin University from 2006 to 2020. Patients were grouped according to age: below 60 years (non-elderly group, n = 5923) and at least 60 years (elderly group, n = 1199). The clinical and pathological characteristics of renal biopsy patients in the groups were analyzed using the t-test and chi-square test.

Results

Compared with the non-elderly group, the elderly group had significantly fewer patients with primary glomerulonephritis, but more patients with tubulointerstitial disorders (p < .05). The incidence of IgA nephropathy, mesangial proliferative glomerulonephritis, and lupus nephritis was significantly lower in elderly patients than in non-elderly patients. The incidence of membranous nephropathy, membranoproliferative glomerulonephritis, diabetic nephropathy, hypertensive nephropathy, systemic vasculitis-associated renal damage, and amyloid nephropathy was significantly higher in elderly patients than in non-elderly patients (p < .05). The incidence of perinephric hematoma (≥4 cm²) in elderly patients with renal biopsy was lower than that in non-elderly patients. We noted that 79.9% of primary glomerulonephritis patients who received immunosuppressive therapy showed a remission rate of 83.5%.

Conclusion

The spectrum of kidney disease in the elderly is different from that in the younger population.

Low-Dose Corticosteroid Combined With Mycophenolate Mofetil for IgA Nephropathy With Stage 3 or 4 CKD: A Retrospective Cohort Study

PURPOSE

This study assessed the long-term (10-year) tolerability and efficacy of a low-dose corticosteroid combined with mycophenolate mofetil (CS + MMF) in the treatment of immunoglobulin A nephropathy (IgAN) with stage 3/4 chronic kidney disease and proteinuria in clinical practice in China.

METHODS

Data from patients with biopsy-proven IgAN, stage 3/4 chronic kidney disease (estimated glomerular filtration rate 15-59 mL/min/1.73 m²), and proteinuria (urinary protein excretion ≥1.0 g/d) and who were treated with uncontrolled supportive care (USC), CS, or CS + MMF between January 2008 and December 2017 were included. The primary end point was the prevalence of the composite outcome of any of the following conditions: a reduction in estimated glomerular filtration rate of ≥50%, end-stage renal disease, and death.

FINDINGS

Of the 120 enrolled patients, 44, 25, and 51 were treated with USC, CS, and CS + MMF, respectively. The median follow-up time was 40.1 months (IQR, 29.1-67.8 months). The prevalences of the composite outcome were 63.6%, 56.0%, and 19.6%, respectively (P < 0.001). The cumulative 5-year renal function-preservation rates were 48.1%, 51.4%, and 83.7%. After adjustment for covariates, the prevalence of the composite outcome was significantly decreased with CS + MMF (HR = 0.094; 95% CI, 0.026-0.335; P < 0.001), but not with CS (HR = 0.749; 95% CI, 0.354-1.583; P = 0.449), compared with USC. However, 4 patients in the CS + MMF group died, of whom 3 had severe pneumonia.

IMPLICATIONS

CS + MMF may have more promising efficacy than USC or CS in renal-function preservation in patients with IgAN and chronic kidney disease in the Chinese population. However, attention should be paid to the increased risk for death due to severe pneumonia.

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.

The Nephroprotective Effect of Lycopene on Renal Ischemic Reperfusion Injury: A Mouse Model

Acute kidney injury (AKI) is characterized by fast decline in renal function within a short period of time. Renal ischemic-reperfusion (I-R) injury is the main cause of AKI. This study aims to investigate the possible nephroprotective effect of lycopene on renal ischemic-reperfusion injury in mice model. Forty Swiss Albino adult male mice were randomly allocated onto one of the four study groups: sham group: mice had median laparotomy under anesthesia with no procedures performed, renal tissues and blood samples were collected. ischemic-reperfusion group (I-R-control): mice underwent median laparotomy under anesthesia, followed by 30 min bilateral renal ischemia. Renal tissues and blood samples were collected after 2 h from reperfusion. Vehicle-treated group: mice were pretreated with intra 1% dimethyl sulfoxide 30 min before inducing ischemia. Lycopene-treated group: mice were pretreated with 10 mg/kg intraperitoneal injection of lycopene 30 min before inducing renal ischemia. Renal tissues, and blood samples were collected after 2 h from reperfusion. Blood and tissue samples were collected to look for evidence of inflammation and necrosis. Blood urea nitrogen, serum creatinine as well as plasma NGAL levels were significantly increased in the active control group (P ≤ 0.05), when compared to the sham group. Similarly, renal levels of Notch2/Hes 1, TLR 2, IL-6, Bax, and F2-isoprostane were significantly increased in the active control group as compared to the sham group (P ≤ 0.05). Moreover, lycopene treatment was found to be significantly effective in reducing the increased levels of these markers after I-R injury (P ≤ 0.05).