Precise diagnosis and typing of early-stage renal immunoglobulin-derived amyloidosis by label-free quantification of parallel reaction monitoring-based targeted proteomics.

BACKGROUND: Early diagnosis and typing are crucial for improving the prognosis of patients with renal amyloidosis. Currently, Untargeted proteomics based precise diagnosis and typing of amyloid deposits are crucial for guiding patient management. Although untargeted proteomics achieve ultra-high-throughput by selecting the most abundant eluting cationic peptide precursors in series for tandem MS events, it lacks in sensitivity and reproducibility, which may not be suitable for early-stage renal amyloidosis with minor damages. Here, we aimed to develop parallel reaction monitoring (PRM)-based targeted proteomics to achieve high sensitivity and specificity by determining absolute abundances and codetecting all transitions of highly repeatable peptides of preselected amyloid signature and typing proteins in identifying early-stage renal immunoglobulin-derived amyloidosis. METHODS AND RESULTS: In 10 discovery cohort cases, Congo red-stained FFPE slices were micro-dissected and analyzed by data-dependent acquisition-based untargeted proteomics for preselection of typing specific proteins and peptides. Further, a list of proteolytic peptides from amyloidogenic proteins and internal standard proteins were quantified by PRM-based targeted proteomics to validate performance for diagnosis and typing in 26 validation cohort cases. The diagnosis and typing effectiveness of PRM-based targeted proteomics in 10 early-stage renal amyloid cases was assessed via a comparison with untargeted proteomics. A peptide panel of amyloid signature proteins, immunoglobulin light chain and heave chain in PRM-based targeted proteomics showed significantly distinguishing ability and amyloid typing performance in patients. The diagnostic algorithm of targeted proteomics with a low amount of amyloid deposits in early-stage renal immunoglobulin-derived amyloidosis showed better performance than untargeted proteomics in amyloidosis typing. CONCLUSIONS: This study demonstrates that the utility of these prioritized peptides in PRM-based targeted proteomics ensure high sensitivity and reliability for identifying early-stage renal amyloidosis. Owing to the development and clinical application of this method, rapid acceleration of the early diagnosis, and typing of renal amyloidosis is expected.

The IRE1/JNK signaling pathway regulates inflammation cytokines and production of glomerular extracellular matrix in the acute kidney injury to chronic kidney disease transition.

BACKGROUND: The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is extremely complex. Incomplete renal tubule repair, inflammation, and endoplasmic reticulum (ER) stress all play major roles. AKI activates ER stress, and the sensor protein inositol-requiring kinase-1 (IRE1) mediates inflammation by promoting the phosphorylation of C-jun NH2-terminal kinase (JNK). The interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling pathway is associated with the secretion of renal extracellular matrix (ECM) and fibrosis. It remains unclear whether these signaling pathways play a role in the AKI-CKD transition. METHODS: In this study, a mouse model of ischemia-reperfusion (I/R) with bilateral renal artery clipping was used. IRE1 or JNK inhibitors were also injected to confirm their roles in the AKI-CKD transition. The renal function of the mice was determined by observing the pathology of the renal tubules and glomeruli through electron microscopy, immunohistochemistry, western blotting and quantitative real-time PCR. RESULTS: I/R stimulates ER stress and the IRE1/JNK pathway in the renal tubules in a short period of time, leading to continuous inflammation. Long-term I/R injury activates the STAT3 pathway in the glomeruli, activates mesangial cells proliferation, causes secretion of large amounts of glomerular ECM, and promotes glomerular sclerosis. This damage to the renal tubules and glomeruli is significantly reduced in I/R model mice pretreated with IRE1 or JNK inhibitors. CONCLUSION: These findings suggested that the IRE1/JNK pathway regulates the inflammatory cytokines caused by AKI and continues to activate the STAT3 pathway and production of ECM in the glomeruli at late stages, suggesting the feasibility of targeted therapy for the AKI-CKD transition.

Role of Human Mesangial-Tubular Crosstalk in Secretory IgA-Induced IgA Nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is characterized by the mesangial deposition of pathogenic IgA. We previously detected the deposition of pathogenic secretory IgA (SIgA) in the mesangium of about one-third of IgAN patients. Tubulointerstitial injury has an important role in the development of IgAN. However, the relationship between SIgA and tubulointerstitial damage is currently unclear. In this work, the role of the mesangial-tubular crosstalk was explored in the tubulointerstitial damage in SIgA-induced IgAN. METHODS: SIgA deposition in renal tissues of IgAN patients was detected by immunofluorescence. Flow cytometry was used to assess the binding of SIgA to human renal mesangial cells (HRMC) and human proximal tubule epithelial (HK-2) cells. HK-2 was co-cultured with HRMC added with SIgA isolated from patients or normal volunteers. Protein synthesis and gene expressions of TNF-α, TGF-ß1, and MCP-1 were determined by ELISA and PCR, respectively. The expressions of the above cytokines in renal tissues of patients and normal controls were detected by immunohistochemistry. RESULTS: Twenty-nine of 96 patients had SIgA deposition in the mesangium, but SIgA was rarely detected in the tubulointerstitium. The binding rate of SIgA to HK-2 (2.79%) was significantly lower than that of HRMC (81.6%) (p < 0.001). The expressions of TNF-α, TGF-ß1, and MCP-1 in HRMC were significantly higher than in SIgA-stimulated HK-2 (p < 0.05), and their expressions were significantly higher in the SIgA-stimulated co-culture group compared with SIgA-stimulated HRMC (p < 0.05). The expressions of the above cytokines were mainly detected in tubulointerstitium of IgAN patients with positive and negative SIgA deposition, without significant difference between the 2 groups, but to a significantly higher level than that in normal controls, and their expressions positively correlated with tubulointerstitial injury. CONCLUSION: Inflammatory factors released from the mesangium after SIgA deposition might mediate tubulointerstitial damage via mesangial-tubular crosstalk in IgAN.

Normotensive and hypertensive Immunoglobulin a nephropathy with ischemic renal injury: clinicopathological characteristics and prognosis.

OBJECTIVES: This study aimed to investigate the clinicopathological characteristics and prognosis of normotensive and hypertensive IgAN patients with ischemic renal injury. METHODS: A total of 344 cases of IgAN with ischemic renal injury were included in the study, including 99 normotensive IgAN patients (28.8%) and 245 hypertensive IgAN patients (71.2%). In addition, 467 IgAN patients without ischemic renal injury were included as controls, including 205 normotensive patients and 262 hypertensive patients. Clinicopathological and prognostic data were collected and analyzed. RESULTS: Compared with patients without ischemic renal injury, IgAN patients with ischemic renal injury displayed a higher proportion of hypertention, a higher proportion of ischemic glomerulosclerosis, tubular atrophy/interstitial fibrosis and vascular lesions (all p < .05). There was no significant difference in cumulative survival between the normotensive IgAN patients groups (Log-rank χ2 = 0.479; p = .489). Furthermore, ischemic renal injury was not a risk factor for end-point events in normotensive IgAN patients (HR = 1.103; 95% CI: 0.279-4.365; p = .889). There was lower cumulative survival in hypertensive IgAN patients with ischemic renal injury (Log-rank χ2 = 11.352, p = .001). Moreover, ischemic renal injury was a risk factor for end-point events in hypertensive IgAN patients (HR = 1.889; 95% CI: 1.124-3.178; p = .016). CONCLUSIONS: Ischemic renal injury can occur in normotensive IgAN patients. Although the pathological changes may not affect the long-term prognosis of normotensive IgAN patients, the prognosis for hypertensive IgAN patients remains poor. Therefore, increased attention should be paid to the clinical management of ischemic lesions in hypertensive IgAN patients.

Association between thrombotic microangiopathy and activated alternative complement pathway in malignant nephrosclerosis.

BACKGROUND: Malignant nephrosclerosis, defined as renal microangiopathy in the setting of severe hypertension, remains a critical renal emergency leading to end-stage renal disease despite aggressive anti-hypertensive treatment. Recently, activation of the complement alternative pathway (AP) has been reported to play a prominent role in the pathogenesis of malignant nephrosclerosis. However, subsequent study failed to recapitulate the findings of genetic complement abnormalities in the disease. This study aimed to determine the presence of AP activation and genetic complement defects and establish their correlations to renal microangiopathy lesions, clinical features and prognosis in patients with malignant nephrosclerosis. METHODS: Fifty patients with malignant hypertension and concomitant thrombotic microangiopathy (TMA) proven by renal biopsy were investigated; 25 cases of kidney donors who received zero-hour allograft biopsies were used as normal controls. Various renal TMA lesions in patients with malignant nephrosclerosis were reviewed and evaluated using a semi-quantitative scoring system. Deposition of C5b-9, C3a, C5a, C4d and mannose-binding lectin was assessed by immunohistochemistry. Co-localization of C5b-9 and CD34 was detected by confocal microscopy. Complement factor B (FB), factor P (FP; properdin), factor D (FD), factor H (FH), C3a and C5a levels were quantified by enzyme-linked immonosorbent assay in plasma and urine samples of patients with malignant nephrosclerosis and controls. Genetic abnormalities of complement components were analysed by whole-exome sequencing. RESULTS: Renal biopsies of malignant nephrosclerosis showed identical histopathological and ultrastructural features to atypical haemolytic uraemic syndrome. C5b-9, C3a and C5a deposits were found along the walls of arteries/arterioles and glomerular capillaries and localized in the endothelial cells. Elevated plasma and urinary levels of FB, FP, FD, C3a and C5a as well as decreased FH levels were observed in patients with malignant nephrosclerosis compared with normal controls. The urinary levels of complement AP components, but not the plasma levels, were correlated with renal functions, prognosis and active TMA lesions except for arteriolar thrombi. Finally, mutations of the MCP, CFB, CFH and CFHR5 genes were identified in 8 of 20 patients with malignant nephrosclerosis. CONCLUSIONS: Aberrant complement AP dysregulation was demonstrated and associated with the activity, severity and renal outcomes of malignant nephrosclerosis. This observation warrants screening for complement defects in patients with malignant nephrosclerosis for the potential use of complement regulators and also highlights the need for further investigation of the precise role of AP in the pathogenesis of the disease.

Expression of soluble epoxide hydrolase in renal tubular epithelial cells regulates macrophage infiltration and polarization in IgA nephropathy.

Tubulointerstitial inflammatory cell infiltration and activation contribute to kidney inflammation and fibrosis. Epoxyeicosatrienoic acids (EETs), which are rapidly metabolized to dihydroxyeicosatrienoic acids by the soluble epoxide hydrolase (sEH), have multiple biological functions, including vasodilation, anti-inflammatory action, and others. Inhibition of sEH has been demonstrated to attenuate inflammation in many renal disease models. However, the relationship between sEH expression and macrophage polarization in the kidney remains unknown. In this study, we investigated the relationships between the level of sEH and clinical and pathological parameters in IgA nephropathy. The level of sEH expression positively correlated with proteinuria and infiltration of macrophages. sEH-positive tubules were found to be surrounded by macrophages. Furthermore, we found that incubation of immortalized human proximal tubular HK-2 cells with total urinary protein and overexpression of sEH promoted inflammatory factor production, which was associated with M1 polarization. We also exposed RAW264.7 mouse leukemic monocytes/macrophages to different HK-2 cell culture media conditioned by incubation with various substances affecting sEH amount or activity. We found that the upregulation of sEH promoted M1 polarization. However, pharmacological inhibition of sEH and supplementation with EETs reversed the conditioning effects of urinary proteins by inhibiting M1 polarization through the NF-κB pathway and stimulating M2 polarization through the phosphatidylinositol 3-kinase pathway. These data suggest that inhibition of sEH could be a new strategy to prevent the progression of inflammation and to attenuate renal tubulointerstitial fibrosis.

Intrarenal Arterial Lesions Are Associated with Higher Blood Pressure, Reduced Renal Function and Poorer Renal Outcomes in Patients with IgA Nephropathy.

BACKGROUND/AIMS: Arterial fibrotic intimal thickening and arteriolar hyaline are considered common pathological features in immunoglobulin A nephropathy (IgAN), whereas little is known about the acute pathological manifestations of endothelial cell injury. The aim of this study was to investigate characteristics of intrarenal arterial lesions and to estimate their prognostic values in patients with IgAN. The primary renal endpoint was a 50% reduction in estimated glomerular filtration rate (eGFR) or end-stage renal disease (ESRD). METHODS: Various renal arterial lesions (arterial fibrotic intimal thickening, arteriolar hyaline, arteriolar endotheliocyte swelling, arteriolar inflammatory cell infiltration, and arteriolar thrombosis) in 1683 patients with IgAN were reviewed and reclassified using a semi-quantitative scoring system. Their correlations with clinical features, pathological characteristics, and renal outcomes were evaluated. RESULTS: The prevalence of intrarenal arterial lesions was up to 72.2% in IgAN patients. There were 978 patients (58.1%) with arterial fibrotic intimal thickening, 350 patients (20.8%) with arteriolar hyaline, 432 patients (25.7%) with arteriolar endotheliocyte swelling, 356 patients (21.2%) with arteriolar inflammatory cell infiltration and 43 patients (2.6%) with arteriolar thrombosis. Arterial fibrotic intimal thickening and arteriolar hyaline were strongly associated with higher mean arterial pressure (MAP) and reduced eGFR (P < 0.001) but were not related to proteinuria at the time of renal biopsy. In contrast, arteriolar endotheliocyte swelling and arteriolar thrombosis were correlated with heavier proteinuria as well as higher MAP and reduced eGFR. During follow-up, patients with vascular lesions received more renin-angiotensin system (RAS) blockade and less glucocorticoid and showed poorer renal outcomes. Univariate Cox model showed that the presence of renal vascular lesions [hazard ratio (HR) = 25.01, 95% confidence interval (CI): 6.19 to 101.03, P < 0.001] was a risk factor for renal outcomes. However, in multivariable Cox analysis, which included clinical factors and the Oxford-MEST-C, vascular lesions were not significantly associated with an increased risk of renal failure. Remarkably, the impact of vascular lesions on the survival from ESRD or 50% reduction in renal function was eliminated by the use of RAS blockade after adjustment for eGFR, proteinuria, and MAP. CONCLUSION: Our study demonstrates the high prevalence of vascular lesions, including the chronic and acute arterial pathological changes, in patients with IgAN. The presence of vascular lesions is associated with higher MAP, reduced eGFR and poorer renal outcomes, which could be influenced by the RAS blockade treatment.

Genetic and Pharmacologic Targeting of Glycogen Synthase Kinase 3ß Reinforces the Nrf2 Antioxidant Defense against Podocytopathy.

Evidence suggests that the glycogen synthase kinase 3 (GSK3)-dictated nuclear exclusion and degradation of Nrf2 is pivotal in switching off the self-protective antioxidant stress response after injury. Here, we examined the mechanisms underlying this regulation in glomerular disease. In primary podocytes, doxorubicin elicited cell death and actin cytoskeleton disorganization, concomitant with overactivation of GSK3ß (the predominant GSK3 isoform expressed in glomerular podocytes) and minimal Nrf2 activation. SB216763, a highly selective small molecule inhibitor of GSK3, exerted a protective effect that depended on the potentiated Nrf2 antioxidant response, marked by increased Nrf2 expression and nuclear accumulation and augmented production of the Nrf2 target heme oxygenase-1. Ectopic expression of the kinase-dead mutant of GSK3ß in cultured podocytes reinforced the doxorubicin-induced Nrf2 activation and prevented podocyte injury. Conversely, a constitutively active GSK3ß mutant blunted the doxorubicin-induced Nrf2 response and exacerbated podocyte injury, which could be abolished by treatment with SB216763. In murine models of doxorubicin nephropathy or nephrotoxic serum nephritis, genetic targeting of GSK3ß by doxycycline-inducible podocyte-specific knockout or pharmacologic targeting by SB216763 significantly attenuated albuminuria and ameliorated histologic signs of podocyte injury, including podocytopenia, loss of podocyte markers, podocyte de novo expression of desmin, and ultrastructural lesions of podocytopathy (such as foot process effacement). This beneficial outcome was likely attributable to an enhanced Nrf2 antioxidant response in glomerular podocytes because the selective Nrf2 antagonist trigonelline abolished the proteinuria-reducing and podocyte-protective effect. Collectively, our results suggest the GSK3ß-regulated Nrf2 antioxidant response as a novel therapeutic target for protecting podocytes and treating proteinuric glomerulopathies.

C3a, C5a renal expression and their receptors are correlated to severity of IgA nephropathy.

BACKGROUND: IgA nephropathy (IgAN) is the most common primary kidney disease, often leading to chronic renal failure. Complement activation products C3a and C5a have broad pro-inflammatory potential through their receptors, C3aR and C5aR, and contribute to the pathogenesis of several inflammatory and autoimmune diseases, but their roles in IgAN are poorly defined. PURPOSE: This study aimed to establish correlations between renal C3a, C5a, C3aR, C5aR, or serum/urinary C3a, C5a with clinical features and renal histopathology in patients with IgAN. METHODS: Eighty-three patients with renal biopsy proven IgAN were investigated. Thirty patients fulfilled Haas's II, 30 fulfilled Haas's III and 23 fulfilled Haas's IV criteria. Deposition of C3a and C5a was assessed by immunohistochemistry. C3aR and C5aR mRNAs and proteins in kidney tissue were examined by real-time quantitative PCR (RT-qPCR) and immunohistochemical staining, respectively. C3a and C5a levels were quantified by ELISA in serum and urine samples of 30 IgAN patients, 10 control subjects and 10 septic patients. RESULTS: Renal C3a and C5a deposition and C3aR and C5aR expression increased with increasing grades of renal pathology in IgAN patients. They positively correlated with proteinuria and serum creatinine (SCr), but not serum C-reactive protein (CRP) or complement 3 (C3). Serum C3a and C5a increased to levels comparable to septic patients but did not differ among IgAN sub-groups. In contrast, urinary C3a and C5a increased significantly and correlated positively with renal pathological grades. CONCLUSIONS: In patients with IgAN, urinary and renal C3a and C5a and renal expression of C3aR and C5aR are significantly correlated with the activity and severity of renal injury. This observation warrants further study into the roles of C3a, C5a and their receptors in the pathogenesis of IgAN and as potential therapeutic targets.

Established the first clinical prediction model regarding the risk of hyperuricemia in adult IgA nephropathy.

OBJECTIVE: To construct a novel nomogram model that predicts the risk of hyperuricemia incidence in IgA nephropathy (IgAN). METHODS: Demographic and clinicopathological characteristics of 1184 IgAN patients in the First Affiliated Hospital of Zhengzhou University Hospital were collected. Univariate analysis and multivariate logistic regression were used to screen out hyperuricemia risk factors. The risk factors were used to establish a predictive nomogram model. The performance of the nomogram model was evaluated using an area under the receiver-operating characteristic curve (AUC), calibration plots, and a decision curve analysis. RESULTS: Independent predictors for hyperuricemia incidence risk included sex, hypoalbuminemia, hypertriglyceridemia, blood urea nitrogen (BUN), estimated glomerular filtration rate (eGFR), 24 h urinary protein (24 h TP), gross hematuria and tubular atrophy/interstitial fibrosis (T). The nomogram model exhibited moderate prediction ability with an AUC of 0.834 (95% CI 0.804-0.864). The AUC from validation reached 0.787 (95% CI 0.736-0.839). The decision curve analysis displayed that the hyperuricemia risk nomogram was clinically applicable. CONCLUSION: Our novel and simple nomogram containing 8 factors may be useful in predicting hyperuricemia incidence risk in IgAN.

Hyperuricemia aggravates the progression of IgA nephropathy.

OBJECTIVE: The relationship between hyperuricemia and IgA nephropathy (IgAN) was evaluated systematically in this research. METHODS: The Preferred Reporting Items for Systematic Review and Meta-analysis statement was employed to design and report the study. RESULTS: Twenty-five studies were included in this meta-analysis with a total of 6048 IgAN patients. The clinical indicators indicated that blood urea nitrogen (BUN) (p < 0.00001, mean difference (MD) = 2.60, 95% confidence interval (CI) 1.74-3.46), serum creatinine (Scr) (p < 0.00001, MD = 44.56, 95% CI 31.15-57.98), diastolic blood pressure(DBP) (p < 0.00001, MD = 3.86, 95% CI 2.84-4.88), systolic blood pressure(SBP) (p < 0.00001, MD = 6.71, 95% CI 4.70-8.71), and 24-h urine protein(24 h TP) (p < 0.00001, MD = 0.76, 95% CI 0.58-0.94) were significantly increased in IgAN with hyperuricemia group than that in normouricemic IgAN group. The pathological analysis indicated that mesangial proliferation (p < 0.00001, MD = 0.12, 95% CI 0.07-0.17), vascular lesion (p < 0.00001, MD = 0.17, 95% CI 0.13-0.20), segmental lesion (p < 0.00001, MD = 0.15, 95% CI 0.03-0.26), tubulointerstitial damage (p < 0.00001, MD = 1.27, 95% CI 1.06-1.48), and glomerulosclerosis (p < 0.00001, MD = 0.56, 95% CI 0.40-0.72) were considerably climbed in IgAN patients with hyperuricemia compared without hyperuricemia group. Additionally, the estimated glomerular filtration rate (p < 0.00001, MD = - 29.03, 95% CI - 36.83 to - 21.23) was decreased in IgAN patients with hyperuricemia compared with normouricemic group. CONCLUSION: Hyperuricemia exacerbates IgAN prognosis through aggravating the clinical outcomes and pathological results of IgAN.

Author Correction: MC1R is dispensable for the proteinuria reducing and glomerular protective effect of melanocortin therapy.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The TLR4-MyD88-NF-κB pathway is involved in sIgA-mediated IgA nephropathy.

Previous studies have shown that secretory IgA (sIgA) was critically involved in IgA nephropathy (IgAN) immune responses. Toll-like receptors (TLRs), especially TLR4 which participates in mucosal immunity, may be involved in the pathogenesis of IgAN. The purpose of this study was to investigate whether sIgA and TLR4 interact to mediate kidney damage in IgAN patients. IgAN patients with positive sIgA deposition in renal tissues were screened by immunofluorescence assay. Patient salivary sIgA (P-sIgA) was collected and purified by jacalin affinity chromatography. Salivary sIgA from healthy volunteers was used as a control (N-sIgA). Expression of TLR4, MyD88, NF-κB, TNF-α, IL-6, and MCP-1 were detected in the mesangial area of IgAN patients by immunohistochemistry, the expression levels in patients with positive sIgA deposition were higher than that with negative sIgA deposition. Human renal mesangial cells (HRMCs) were cultured in vitro, flow cytometry showed that P-sIgA bound HRMCs significantly better than N-sIgA. HRMCs were cultured in the presence of sIgA (400 µg/mL) for 24 h, compared with cells cultured with N-sIgA, HRMCs cultured in vitro with P-sIgA showed enhanced expression of TLR4, increased secretion of TNF-α, IL-6, and MCP-1, and increased expression of MyD88/NF-κB. TLR4 shRNA silencing and NF-κB inhibition both reduced the ability of HRMCs to synthesize TNF-α, IL-6, and MCP-1. Our results indicate that sIgA may induce high expression of TLR4 in HRMCs and further activate downstream signalling pathways, prompting HRMCs to secrete multiple cytokines and thereby mediating kidney damage in IgAN patients.

Spectrum of biopsy proven renal diseases in Central China: a 10-year retrospective study based on 34,630 cases.

Chronic kidney diseases have become a major issue worldwide. The spectrum of biopsy proven renal diseases differs between locations and changes over time. It is therefore essential to describe the local epidemiological trends and the prevalence of renal biopsy in various regions to shine new light on the pathogenesis of various renal diseases and provide a basis for further hypothesis-driven research. We retrospectively analyzed 34,630 hospitalized patients undergoing native renal biopsy between January 1, 2009 and December 31, 2018. Indications for renal biopsy and histological diagnosis were analyzed to describe the prevalence of renal biopsy, and changing prevalence between period 1 (2009-2013) and period 2 (2014-2018) were further analyzed. Nephrotic syndrome (NS) was the most common indication for biopsy. Membranous nephropathy (MN, 24.96%) and IgA nephropathy (IgAN, 24.09%) were the most common primary glomerulonephritis (PGN). MN was most common in adults, with IgAN more prevalent in children. Lupus nephritis (LN) was the most common secondary glomerulonephritis (SGN) in adults, while Henöch-Schönlein purpura nephritis (HSPN) in children. The prevalence of MN increased significantly and nearly doubled from period 1 (15.98%) to period 2 (30.81%) (P = 0.0004). The same trend appeared with membranoproliferative glomerulonephritis (MPGN), diabetic nephropathy (DN) and obesity-related glomerulopathy (ORG), while the frequencies of minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), LN and hepatitis B associated glomerulonephritis (HBV-GN) significantly decreased between the two intervals. NS was the most common indication for biopsy across all age groups and genders. MN has overtaken IgAN to become the most common PGN in adults, while IgAN was the most common PGN in children. LN was the most common SGN in adults, and HSPN the most common in children.

Low copy number of FCGR3B is associated with lupus nephritis in a Chinese population.

Lupus nephritis (LN) is a polygenic disease caused by an interaction between hereditary and environmental factors. Numerous gene copy number variations have been identified to contribute to this disease. Previously, immunoglobulin (Ig)G Fcγ receptor 3B (FCGR3B) copy number variation (CNV) was reported to be associated with LN in the Caucasian population. However, the effect of FCGR3B CNV on LN in the Chinese population remains unknown. The present study aimed to investigate whether CNVs of FCGR3B are associated with LN in the Henan Chinese population. FCGR3B CNVs were determined in 142 LN patients and 328 healthy controls. A modified methodology based on competitive polymerase chain reaction, a Multiplex AccuCopy™ kit was used to detect FCGR3B copy number. Clinical and laboratory data was collected retrospectively from medical records. To evaluate associations between FCGR3B CNVs and LN susceptibility, the present study calculated the odds ratios using a logistic regression analysis. The current study identified that the distribution of FCGR3B copy number was significantly different between LN and healthy controls (P=0.031). A low copy number (<2) of FCGR3B was significantly enriched in LN patients (P=0.042), and was a risk factor for LN (odds ratio=2.059; 95% confidence interval, 1.081-3.921; P=0.028). However, a high copy number (>2) had no effect on LN. There were no associations between FCGR3B CNV and clinical phenotypes of LN. The results from the present study demonstrate that a low copy number of FCGR3B is a risk factor for LN in a Chinese population.

Dividing CKD stage 3 into G3a and G3b could better predict the prognosis of IgA nephropathy.

Chronic kidney disease (CKD) stage 3 was divided into stage G3a and stage G3b in the 2013 Kidney Disease Improving Global Outcomes guidelines. Whether it is appropriate to regard 45 mL/min/per 1.73 m2 as the threshold value of G3a/G3b staging and whether dividing CKD stage 3 into G3a/G3b plays a useful role in assessing the prognosis of patients with IgA nephropathy (IgAN) remain unknown. Three hundred and ninety patients from the First Affiliated Hospital of Zhengzhou University and Peking University First Hospital diagnosed with IgAN in CKD stage 3 were enrolled and successfully followed up. Cox proportional hazards model was used to analyze hazard ratios of reaching the composite endpoints (doubling of serum creatinine, end-stage renal disease: estimated glomerular filtration rate (eGFR) <15 ml/min/per 1.73 m2 or renal replacement therapy, or death) for patients with different eGFR and risk factors affecting composite endpoints. The Kaplan-Meier method was used to calculate the cumulative renal survival rate of patients. When eGFR was lower than 45 ml/min/per 1.73 m2, the hazard ratio increased sharply for patients in CKD stage 3 who reached the composite endpoints. Renal injury and prognosis were significantly different between patients in the G3a and G3b groups. Stage G3b was a major risk factor affecting prognosis. A threshold value of 45 ml/min/per 1.73 m2 appears appropriate to assess the prognosis of IgAN patients with CKD stage 3. Dividing IgAN patients with CKD stage 3 into G3a and G3b is very useful to help understand disease conditions and for predicting the risk for disease progression.

Membranous nephropathy associated with malignant pleural mesothelioma in an adult patient: A case report.

A 23-year-old man presented to our hospital with membranous nephropathy and received a detailed examination, including pleural biopsy, due to a feeling of chest oppression. The result of the pleural biopsy was malignant pleural mesothelioma. However, the patient did not have a history of asbestos or tobacco exposure. A review of the English literature identified only 7 reported cases of concomitant malignant mesothelioma and nephrotic syndrome. Furthermore, among the 7 cases reviewed, 6 had a history of asbestos exposure, 1 had a history of prolonged tobacco exposure and in only 1 case the renal pathology results revealed the presence of membranous nephropathy.

The accuracy of the anti-phospholipase A2 receptor antibody in the diagnosis of idiopathic membranous nephropathy: a comparison of different cutoff values as measured by the ELISA method.

AIM: Recent studies have revealed that anti-phospholipase A2 receptor antibodies (aPLA2R-ABs) may play a role in the diagnosis of idiopathic membranous nephropathy (IMN). We will investigate the application of an aPLA2R-AB with different cutoff values for diagnosing IMN. METHODS: From August 2014 to December 2014, patients with proteinuria greater than 1 g/day were screened at the First Affiliated Hospital of Zhengzhou University. Patients were divided into the IMN and non-IMN groups based on the results of renal biopsy. The sensitivity, specificity, and receiver operating characteristic (ROC) curve of aPLA2R-AB for diagnosing IMN were analyzed. RESULTS: A total of 229 patients (113 males, average age of 45.3 ± 15.8 years) were enrolled in this study, and 118 patients were diagnosed with IMN. The sensitivity/specificity of aPLA2R-AB in the diagnosis of IMN was 65.3/97.3 %, 60.2/97.3 %, and 45.8/97.3 % for the different cutoff values (14, 20, and 40 RU/ml). The area of the ROC curve was 0.87. CONCLUSION: Anti-PLA2R-AB with a cutoff value of 14 RU/ml based on the ELISA method plays an important role in the diagnosis of IMN.

MC1R is dispensable for the proteinuria reducing and glomerular protective effect of melanocortin therapy.

Melanocortin therapy by using adrenocorticotropic hormone (ACTH) or non-steroidogenic melanocortin peptides attenuates proteinuria and glomerular injury in experimental glomerular diseases and induces remission of nephrotic syndrome in patients with diverse glomerulopathies, even those resistant to steroids. The underlying mechanism remains elusive, but the role of melanocortin 1 receptor (MC1R) has been implicated and was examined here. Four patients with congenital red hair color and nephrotic syndrome caused by idiopathic membranous nephropathy or focal segmental glomerulosclerosis were confirmed by gene sequencing to bear dominant-negative MC1R mutations. Despite prior corticosteroid resistance, all patients responded to ACTH monotherapy and ultimately achieved clinical remission, inferring a steroidogenic-independent and MC1R-dispensable anti-proteinuric effect of melanocortin signaling. In confirmatory animal studies, the protective effect of [Nle(4), D-Phe(7)]-α-melanocyte stimulating hormone (NDP-MSH), a potent non-steroidogenic pan-melanocortin receptor agonist, on the lipopolysaccharide elicited podocytopathy was completely preserved in MC1R-null mice, marked by reduced albuminuria and diminished histologic signs of podocyte injury. Moreover, in complementary in vitro studies, NDP-MSH attenuated the lipopolysaccharide elicited apoptosis, hypermotility and impairment of filtration barrier function equally in primary podocytes derived from MC1R-null and wild-type mice. Collectively, our findings suggest that melanocortin therapy confers a proteinuria reducing and podoprotective effect in proteinuric glomerulopathies via MC1R-independent mechanisms.

Retrospective study of mycophenolate mofetil treatment in IgA nephropathy with proliferative pathological phenotype.

BACKGROUND: Mycophenolate mofetil (MMF) and cyclophosphamide (CTX) are widely used in treating various kidney diseases. However, whether they are effective and which one is better for treating IgA nephropathy patients with proliferative pathological phenotype in renal diseases, such as endocapillary proliferation, cellular crescents, and/or capillary loops fibrinoid necrosis is still unknown. We, therefore, initiated a study to compare the effects of MMF and CTX in treating IgA nephropathy with the above pathological lesions. METHODS: One hundred and nineteen patients with IgA nephropathy who had at least one of the three aforementioned lesions were enrolled. All patients were treated with prednisone; 48 patients received prednisone only (Pred group), 40 received MMF and prednisone (MMF + Pred group), and 31 were treated with CTX and prednisone (CTX + Pred group). The median time of follow-up was 30 months (maximum: 96 months). The primary endpoint was defined as renal survival. The incidence of remission of proteinuria was the secondary endpoint. RESULTS: Serum creatinine in all groups declined significantly at different follow-up times (P = 0.002), and the differences among the three groups were significant (P < 0.001). At 24 months of follow-up, the decline rates were 12.35%, 32.95%, and 24.14% in the Pred, MMF + Pred, and CTX + Pred groups respectively. For urine protein excretion, the decline rates were 49.12% (Pred), 73.67% (MMF + Pred), and 63.53% (CTX + Pred) respectively at 24 months of follow-up. The differences among the three groups were not significant (P = 0.714). Renal survival (the primary endpoint) was significantly different (P = 0.027); however, the sencondary endpoint was similar for all the three groups (P = 0.100). CONCLUSIONS: For IgA nephropathy patients with endocapillary proliferation, cellular crescents, and/or fibrinoid necrosis of capillary loops, prednisone combined with MMF was more effective in lowering the serum creatinine than with CTX. Combined MMF and prednisone treatment led to a better renal survival compared to that of prednisone with CTX.