NLRP3 inflammasome activation and macrophage distribution in kidney tissues from patients with acute oxalate nephropathy.

Background: The current study was initiated to evaluate renal nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome pathway activation and macrophage subtype distribution and their clinicopathological significance in a cohort of oxalate-induced acute kidney injury. Methods: Twelve patients with biopsy-proven acute oxalate nephropathy (AON) from January 2016 to October 2022 were retrospectively enrolled, with estimated glomerular filtration rate (eGFR)-matched 24 patients with acute tubulointerstitial nephritis (ATIN) as disease control. Pathological lesions as well as markers of NLRP3 inflammasome pathway and macrophage phenotype detected by immunohistochemistry staining were semi-quantitatively analyzed. Results: Oxalate depositions were found in 5% to 20% of tubules with a positive correlation with Sirius Red staining in AON specimens (rp = 0.668, p = 0.02). Disruption of tubular basement membrane and inflammatory cell reaction was more prominent in specimens of AON (both p < 0.05) as compared with ATIN specimens. The expressions of NLRP3, caspase-1, and gasdermin D were significantly increased in AON specimens as well (all p < 0.05). Patients with M1/M2 macrophage ratio <1 were found with more chronic tubulointerstitial lesions and presented with lower eGFR at the last follow-up (24.8  10.6 mL/min/1.73 m2 vs. 55.1  21.2 mL/min/1.73 m2, p = 0.02) in the AON group. Conclusion: The NLRP3 inflammasome pathway was activated in the kidneys of AON patients, and the ratio of M1 and M2 macrophages was associated with chronicity of pathological changes, which needs further exploration.

The anti-mCRP199-206 antibodies aggravate tubulointerstitial lesions in lupus nephritis.

Tubulointerstitial lesions could also be prominent in lupus nephritis, and the pathogenesis of tubulointerstitial lesions may be different from glomerular lesions. Previous studies have showed that plasma antibodies against modified /monomeric C-reactive protein (mCRP) are associated with renal tubulointerstitial lesions in patients with lupus nephritis, and amino acid (aa) 199-206 was one of the major epitopes of mCRP. However, the role of anti-mCRP199-206 antibodies in the pathogenesis of tubulointerstitial lesions in lupus nephritis is unknown. A total of 95 patients with renal biopsy-proven lupus nephritis were enrolled in this study. Plasma levels of anti-mCRP199-206 antibodies were screened by enzyme-linked immunosorbent assay (ELISA). A lupus prone mouse model was immunized using peptides mCRP199-206 to explore the potential role of anti-mCRP199-206 antibodies in tubulointerstitial lesions. The mechanism of anti-mCRP199-206 antibodies damage to renal tubular epithelial cells was investigated in vitro. Plasma antibodies against mCRP199-206 were associated with renal tubulointerstitial lesions and prognosis in patients with lupus nephritis. Immunization with peptides mCRP199-206 in lupus prone mice could aggravate tubulointerstitial lesions and drive tubulointerstitial inflammation and fibrosis. Anti-mCRP 199-206 antibodies could activate the TGF-ß1/Smad3 signal pathway and induce tubular damage by binding with CRP. Circulating antibodies against mCRP199-206 could be a biomarker to reveal tubulointerstitial lesion, and participate in the pathogenesis of tubulointerstitial lesions, which might provide a potential therapeutic target for lupus nephritis.

Advantages of metagenomic next-generation sequencing in the management of ANCA-associated vasculitis patients with suspected pulmonary infection as a rule-out tool.

OBJECTIVE: Pulmonary infection is one of the leading causes of death in patients with ANCA-associated vasculitis (AAV). It is sometimes difficult to differentiate pulmonary infection from pulmonary involvement of vasculitis in AAV patients. Fiberoptic bronchoscopy and bronchoalveolar lavage fluid (BALF) assays are useful diagnostic methods. In addition to conventional microbiological tests (CMTs), metagenomic next-generation sequencing (mNGS) facilitates rapid and sensitive detection of various pathogens. The current study aimed to evaluate the advantages of additional BALF mNGS in the management of pulmonary infection in AAV patients. METHODS: 27 patients with active AAV and suspected pulmonary infection whose BALF samples were tested by mNGS and CMTs and 17 active AAV patients whose BALF were tested by CMTs alone were retrospectively recruited. The results of microbiological tests, and adjustments of treatment following BALF mNGS, were described. The durations of antimicrobial treatment and in-hospital mortality in patients were compared. RESULTS: Among the 27 patients whose BALF samples were tested by mNGS, 25.9% of patients did not have evidence of pathogenic microorganism in their BALF samples, 55.6% had polymicrobial infections, including bacteria, fungi and viruses. Of these 27 patients, 40.7% did not have evidence of pathogenic microorganism in their BALF or serum samples according to CMTs. Patients in the BALF mNGS/CMT group received a significantly shorter duration of antibacterial and total antimicrobial treatment than patients in the CMT alone group (17.3 ± 14.7 vs. 27.9 ± 19.0 days, P = 0.044; 18.9 ± 15.0 vs. 29.5 ± 17.7 days, P = 0.040, respectively). Fewer patients in the BALF mNGS/CMT group died than in the CMT alone group (4/27 vs. 7/17, P = 0.049). CONCLUSION: Compared with CMT alone, additional mNGS tests may shorten the duration of antimicrobial treatment and possibly decrease death from severe infection by providing precise and quick diagnosis of infection.

Association of podocyte ultrastructural changes with proteinuria and pathological classification in type 2 diabetic nephropathy.

AIMS: Podocyte injury plays an essential role in the progression of diabetic nephropathy (DN). The associations between the ultrastructural changes of podocyte with proteinuria and the pathological classification of DN proposed by Renal Pathology Society (RPS) have not been clarified in patients with type 2 diabetic nephropathy (T2DN). METHODS: We collected 110 patients with kidney biopsy-confirmed T2DN at Peking University First Hospital from 2017 to 2022. The morphometric analysis on the podocyte foot process width (FPW) and podocyte detachment (PD) as markers of podocyte injury was performed, and the correlations between the ultrastructural changes of podocytes with severity of proteinuria and the RPS pathological classification of DN were analyzed. RESULTS: Mean FPW was significantly broader in the group of T2DN patients with nephrotic proteinuria (565.1 nm) than those with microalbuminuria (437.4 nm) or overt proteinuria (494.6 nm). The cut-off value of FPW (> 506 nm) could differentiate nephrotic proteinuria from non-nephrotic proteinuria with a sensitivity of 75.3% and a specificity of 75.8%. Percentage of PD was significantly higher in group of nephrotic proteinuria (3.2%) than that in microalbuminuria (0%) or overt proteinuria (0.2%). FPW and PD significantly correlated with proteinuria in T2DN (r = 0.473, p < 0.001 and r = 0.656, P < 0.001). FPW and PD correlated with RPS pathological classification of T2DN (r = 0.179, P = 0.014 and r = 0.250, P = 0.001). FPW value was increased significantly with more severe DN classification (P for trend =0.007). The percentage of PD tended to increase with more severe DN classification (P for trend = 0.017). CONCLUSIONS: Podocyte injury, characterized by FPW broadening and PD, was associated with the severity of proteinuria and the pathological classification of DN.

Malignancy is increased in patients with antineutrophil cytoplasmic antibody-associated vasculitis in China.

OBJECTIVE: It has been reported that in western countries malignancy risk was higher in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) compared with that in the general population. In the current study, we investigated the incidence, spectrum and risk factors of malignancy in Chinese AAV patients. METHODS: AAV patients diagnosed from 1995 to 2021 in Peking University First Hospital with a follow-up more than 12 months were recruited. Standardized incidence ratios (SIR) were calculated to describe the risk of malignancy, adjusted for sex, age and follow-up time. RESULTS: A total of 552 AAV patients were recruited, among which 23 patients had malignancies either preceding or concurrent with AAV diagnosis, and 43 of the remaining 529 patients developed malignancies within 4.3 ± 4.2 years post AAV diagnosis (SIR: 2.24; 95% CI: 1.68-2.99; p < 0.001). Among these 66 patients, twenty different sites of malignancy were observed, lung cancer being most frequent. To get exactly expected malignancies for the calculation of SIR, 529 patients without preceding or concurrent malignancies were included in the following analysis. Lung cancer was still the leading malignancy diagnosis (SIR: 5.01; 95% CI: 3.29-7.62), followed by malignancies in the kidney, bladder, ureter and prostate. Male gender (HR:2.84; 95%CI:1.36-5.96; p = 0.006) and older age (per year, HR:1.04; 95%CI:1.00-1.07; p = 0.038) were significantly associated with increased risk of malignancy. For patients with malignancy developed beyond 5 years after the diagnosis of AAV, a significantly higher malignancy risk was observed in those with a cumulative cyclophosphamide dose over 20.0 g (SIR: 11.54; 95% CI: 4.77-27.93; p < 0.001). Within the first 2 years after the diagnosis of AAV, the risk of malignancy was still significantly higher than that in the general population, but the cumulative cyclophosphamide dose was not significantly associated with malignancy occurrence in this subgroup of patients. CONCLUSIONS: Malignancy risk is higher in Chinese AAV patients than that in the general population, with a different malignancy spectrum from western countries. Both the use of cyclophosphamide and AAV per se might be associated with higher incidence of malignancy occurrence.

External Validation of the Kidney Failure Risk Equation Among Urban Community-Based Chinese Patients With CKD.

Rationale & Objective: The Kidney Failure Risk Equations have been proven to perform well in multinational databases, whereas validation in Asian populations is lacking. This study sought to externally validate the equations in a community-based chronic kidney disease cohort in China. Study Design: A retrospective cohort study. Setting & Participants: Patients with and estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2 dwelling in an industrialized coastal city of China. Exposure: Age, sex, eGFR, and albuminuria were included in the 4-variable model, whereas serum calcium, phosphate, bicarbonate, and albumin levels were added to the previously noted variables in the 8-variable model. Outcome: Initiation of long-term dialysis treatment. Analytical Approach: Model discrimination, calibration, and clinical utility were evaluated by Harrell's C statistic, calibration plots, and decision curve analysis, respectively. Results: A total of 4,587 participants were enrolled for validation of the 4-variable model, whereas 1,414 were enrolled for the 8-variable model. The median times of follow-up were 4.0 (interquartile range: 2.6-6.3) years for the 4-variable model and 3.4 (2.2-5.6) years for the 8-variable model. For the 4-variable model, the C statistics were 0.750 (95% CI: 0.615-0.885) for the 2-year model and 0.766 (0.625-0.907) for the 5-year model, whereas the values were 0.756 (0.629-0.883) and 0.774 (0.641-0.907), respectively, for the 8-variable model. Calibration was acceptable for both the 4-variable and 8-variable models. Decision curve analysis for the models at the 5-year scale performed better throughout different net benefit thresholds than the eGFR-based (<30 mL/min/1.73 m2) strategy. Limitations: A large proportion of patients lack albuminuria measurements, and only a subset of population could provide complete data for the 8-variable equation. Conclusions: The kidney failure risk equations showed acceptable discrimination and calibration and better clinical utility than the eGFR-based strategy for incidence of kidney failure among community-based urban Chinese patients with chronic kidney disease.

Accurate and reliable risk evaluation of chronic kidney disease (CKD) prognosis can be helpful for physicians to make decisions concerning treatment opportunity and therapeutic strategy. The kidney failure risk equation is an outstanding model for predicting risk of kidney failure among patients with CKD. However, the equation is lacking validation among Chinese populations. In the current study, we demonstrated that the equation had good discrimination among an urban community-based cohort of patients with CKD in China. The calibration was also acceptable. Decision curve analysis also showed that the equation performed better than a traditional kidney function-based strategy. The results provide the basis for using predictions derived from the kidney failure risk equation to improve the management of patients with CKD in community settings in China.

Clinicopathological characteristics and gene mutations in 11 patients with lipoprotein glomerulopathy.

OBJECTIVE: Lipoprotein glomerulopathy (LPG) is a rare disorder characterized by the development of glomerular lipoprotein thrombosis. LPG exhibits familial aggregation, with mutations in the apolipoprotein E (APOE) gene identified as the leading cause of this disease. This study aimed to investigate APOE gene mutations and the clinicopathological features in eleven LPG patients. METHODS: Clinicopathological and follow-up data were obtained by extracting DNA, followed by APOE coding region sequencing analysis. This study analyzed clinical and pathological manifestations, gene mutations, treatment and prognosis. RESULTS: The mean age of the eleven patients was 33.82 years. Among them, five had a positive family history for LPG, ten presented with proteinuria, four exhibited nephrotic syndrome, and six presented with microscopic hematuria. Dyslipidemia was identified in ten patients. In all renal specimens, there was evident dilation of glomerular capillary lumens containing lipoprotein thrombi, and positive oil red O staining was observed in frozen sections of all samples. APOE gene testing revealed that one patient had no mutations, while the remaining ten patients exhibited mutations in the APOE gene, with three patients presenting with multiple mutations simultaneously. Following the confirmation of LPG diagnosis, treatment with angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) was initiated, and the disease progressed slowly. CONCLUSION: LPG is histologically characterized by lamellated lipoprotein thrombi in glomeruli, and kidney biopsy is essential for diagnosis. Mutations in the APOE gene are the leading cause of LPG. This study revealed clinicopathological characteristics and APOE gene mutations in patients with LPG, which helps us better understand the disease.

Surgical procedure and recurrence of upper urinary tract stone: a national-wide study based on hospitalized patients.

PURPOSE: This study aimed to investigate the influence of surgical intervention on recurrence risk of upper urinary tract stone and compare the medical burden of various surgical procedures. METHODS: This study analyzed data from patients with upper urinary tract stone extracted from a national database of hospitalized patients in China, from January 2013 to December 2018. Surgical recurrence was defined as patients experience surgical procedures for upper urinary tract stone again with a time interval over 90 days. Associations of surgical procedures with surgical recurrence were evaluated by Cox regression. RESULTS: In total, 556,217 patients with upper urinary tract stone were included in the present analysis. The mean age of the population was 49.9 ± 13.1 years and 64.1% were men. During a median follow-up of 2.7 years (IQR 1.5-4.0 years), 23,012 patients (4.1%) had surgical recurrence with an incidence rate of 14.9 per 1000 person-years. Compared to patients receiving open surgery, ESWL (HR, 1.59; 95% CI 1.49-1.70), URS (HR, 1.38; 95% CI 1.31-1.45), and PCNL (HR, 1.11; 95% CI 1.06-1.18) showed a greater risk for surgical recurrence. Patients receiving ESWL had the shortest hospital stay length and the lowest cost among the 4 procedures. CONCLUSIONS: Compared with open surgery, ESWL, URS, and PCNL are associated with higher risks of surgical recurrence for upper urinary tract stone, while ESWL showed the least medical burden including both expenditure and hospital stay length. How to keep balance of intervention efficacy and medical expenditure is an important issue to be weighed cautiously in clinic practice and studied more in the future.

Evaluation of the Risk Prediction Models in Predicting Kidney Outcomes in Antiglomerular Basement Membrane Disease.

Introduction: A previous study showed that the renal risk score (RRS) was transferrable to antiglomerular basement membrane (anti-GBM) disease and proposed a risk stratification according to the need of renal replacement therapy (RRT) and the percentage of normal glomeruli (N). Herein, we analyzed the risk factors associated with kidney outcomes in patients with biopsy-proven anti-GBM disease and evaluated these 2 prognosis systems. Methods: A total of 120 patients with biopsy-proven anti-GBM disease with complete clinicopathologic and outcome data were analyzed. Results: The median time to kidney biopsy was 41 days (interquartile range [IQR]: 22-63 days). RRT and N were the only independent predictors of end-stage kidney disease (ESKD). Patients with N ≥10% were more likely to achieve ESKD-free outcomes, even in the subcohort of patients who underwent posttreatment biopsies (P < 0.001). N and serum creatinine at presentation (cut-off values 750 µmol/l and 1300 µmol/l) were 2 independent factors for predicting kidney recovery. The RRS and the risk stratification tool exhibited predictive value for ESKD and could be transferred to patients with kidney biopsy following treatment (Harrell's C statistic [C] = 0.738 and C = 0.817, respectively). However, a cross-over of outcomes among groups was observed in the risk stratification tool in long-term follow-up, when patients with RRT and N ≥10% achieved better kidney outcomes than those without RRT but N <10%. Conclusion: Normal glomeruli percentage, even posttreatment, was a strong indicator for kidney outcomes, especially on long-term prognosis. Serum creatinine is a predictor for kidney recovery, independent of biopsy findings. The risk stratification tool for kidney survival was transferrable to patients with anti-GBM disease with biopsy following treatment in our cohort; however, this needs further validations for long-term outcomes.

The Difference Between Cystatin C- and Creatinine-Based Estimated Glomerular Filtration Rate and Risk of Diabetic Microvascular Complications Among Adults With Diabetes: A Population-Based Cohort Study.

OBJECTIVE: The impact of the difference between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff) on diabetic microvascular complications (DMCs) remains unknown. We investigated the associations of eGFRdiff with overall DMCs and subtypes, including diabetic retinopathy (DR), diabetic kidney disease (DKD), and diabetic neuropathy (DN). RESEARCH DESIGN AND METHODS: This prospective cohort study included 25,825 participants with diabetes free of DMCs at baseline (2006 to 2010) from the UK Biobank. eGFRdiff was calculated using both absolute difference (eGFRabdiff) and the ratio (eGFRrediff) between cystatin C- and creatinine-based calculations. Incidence of DMCs was ascertained using electronic health records. Cox proportional hazards regression models were used to evaluate the associations of eGFRdiff with overall DMCs and subtypes. RESULTS: During a median follow-up of 13.6 years, DMCs developed in 5,753 participants, including 2,752 cases of DR, 3,203 of DKD, and 1,149 of DN. Each SD decrease of eGFRabdiff was associated with a 28% higher risk of overall DMCs, 14% higher risk of DR, 56% higher risk of DKD, and 29% higher risk of DN. For each 10% decrease in eGFRrediff, the corresponding hazard ratios (95% CIs) were 1.16 (1.14, 1.18) for overall DMCs, 1.08 (1.05, 1.11) for DR, 1.29 (1.26, 1.33) for DKD, and 1.17 (1.12, 1.22) for DN. The magnitude of associations was not materially altered in any of the sensitivity analyses. CONCLUSIONS: Large eGFRdiff was independently associated with risk of DMCs and its subtypes. Our findings suggested monitoring eGFRdiff in the diabetes population has potential benefit for identification of high-risk patients.

Light-chain proximal tubulopathy: a retrospective study from a single Chinese nephrology referral center.

Background: Light-chain proximal tubulopathy (LCPT) is a rare disease characterized by the accumulation of monoclonal light chains within proximal tubular cells. This study aimed to investigate the clinical characteristics of LCPT from a single Chinese nephrology referral center.Methods: Patients with kidney biopsy-proven isolated LCPT between 2016 and 2022 at Peking University First Hospital were retrospectively included. Clinical data, kidney pathological type, treatment, and prognosis were analyzed.Results: Nineteen patients were enrolled, the mean age at diagnosis was 57 ± 11 and the sex ratio was 6/13 (female/male). Mean proteinuria was 2.44 ± 1.89 g/24 hr and the mean estimated glomerular filtration rate (eGFR) at the point of biopsy was 59.640 ± 27.449 ml/min/1.73 m2. κ-restriction (84%) was dominant among LCPTs. An abnormal free light chain ratio was observed in 86% of the patients. Proximal tubulopathy with cytoplasmic inclusions accounted for the majority (53%), followed by tubulopathy associated with interstitial inflammation reaction (26%), proximal tubulopathy without cytoplasmic inclusions (16%), and proximal tubulopathy with lysosomal indigestion/constipation (5%). One patient presented with acute kidney injury and 16 patients presented with chronic kidney disease. Regarding follow-up, patients received bortezomib-based or R-CHOP chemotherapy or supportive treatment only. The mean follow-up time was 22 ± 16 months, and the mean eGFR was 63.098 ± 27.439 ml/min/1.73 m2 at the end of follow-up. These patients showed improved or stable kidney function.Conclusions: This is the first case series report of LCPT in four different pathological types in northern China. Clone-targeted chemotherapy may help preserve the kidney function in these patients.

Diabetes mellitus: association of cystatin C- versus creatinine-based estimated glomerular filtration rate with mortality and cardiovascular events.

BACKGROUND: To explore the association between the differences between cystatin C- and creatinine-based estimated glomerular filtration rate (eGFRdiff), and the risk of mortality and cardiovascular (CV) events in individuals with diabetes. METHODS: Three prospective cohorts analyzed data from adults with diabetes from the Incident, Development, and Prognosis of Diabetic Kidney Disease (INDEED) study (2016-17 to 2020) in China, the National Health Nutrition Examination Survey (NHANES, 1999-2004 to 2019) in the USA and UK Biobank (UKB, 2006-10 to 2022) in the UK. Baseline eGFRdiff was calculated using both absolute difference between cystatin C- and creatinine-based calculations (eGFRabdiff), and the ratio between them (eGFRrediff). Cox proportional hazards regression models were used to investigate the association between eGFRdiff and outcomes including all-cause mortality and incident CV events. RESULTS: A total of 8129 individuals from INDEED (aged 60.7 ± 10.0 years), 1634 from NHANES (aged 62.5 ± 14.4 years) and 29 358 from UKB (aged 59.4 ± 7.3 years) were included. At baseline, 43.6%, 32.4% and 42.1% of participants in INDEED, NHANES and UKB, respectively, had an eGFRabdiff value ≥15 mL/min/1.73 m2. During a median follow-up of 3.8 years for INDEED, 15.2 years for NHANES and 13.5 years for UKB, a total of 430, 936 and 6143 deaths and a total of 481, 183 and 5583 CV events occurred, respectively. Each 1-standard deviation higher baseline eGFRabdiff was independently associated with a lower risk of all-cause mortality and CV events, with hazard ratios of 0.77 and 0.82 in INDEED, 0.70 and 0.68 in NHANES, and 0.66 and 0.78 in UKB. Similar results were observed for eGFRrediff. CONCLUSIONS: eGFRdiff represents a marker of adverse events for diabetes among general population. Monitoring both eGFRcys and eGFRcr yields additional prognostic information and has clinical utility in identifying high-risk individuals for mortality and CV events.

Clinical and immunological characteristics of patients with combined anti-glomerular basement membrane disease and IgA nephropathy.

Background: The combination of anti-glomerular basement membrane (GBM) disease and immunoglobulin A nephropathy (IgAN) has been well documented in sporadic cases, but lacks overall assessment in large collections. Herein, we investigated the clinical and immunological characteristics and outcome of this entity. Methods: Seventy-five consecutive patients with biopsy-proven anti-GBM disease from March 2012 to March 2020 were screened. Among them, patients with concurrent IgAN were identified and enrolled. The control group included biopsied classical anti-GBM patients during the same period, excluding patients with IgAN, other glomerular diseases or tumors, or patients with unavailable blood samples and missing data. Serum IgG and IgA autoantibodies against GBM were detected by enzyme-linked immunosorbent assay, as were circulating IgG subclasses against GBM. Results: Fifteen patients with combined anti-GBM disease and IgAN were identified, accounting for 20% (15/75) of all patients. Among them, nine were male and six were female, with an average (± standard deviation) age of 46.7 ± 17.3 years. Thirty patients with classical anti-GBM disease were enrolled as controls, with 10 males and 20 females at an average age of 45.4 ± 15.3 years. Patients with combined anti-GBM disease and IgAN had restricted kidney involvement without pulmonary hemorrhage. Compared with classical patients, anti-GBM patients with IgAN presented with significantly lower levels of serum creatinine on diagnosis (6.2 ± 2.9 vs 9.5 ± 5.4 mg/dL, P = .03) and less occurrence of oliguria/anuria (20%, 3/15 vs 57%, 17/30, P = .02), but more urine protein excretion [2.37 (1.48, 5.63) vs 1.11 (0.63, 3.90) g/24 h, P = .01]. They showed better kidney outcome during follow-up (ESKD: 47%, 7/15 vs 80%, 24/30, P = .03). The autoantigen and epitope spectrum were comparable between the two groups, but the prevalence of circulating anti-α3(IV)NC1 IgG1 (67% vs 97%, P = .01) and IgG3 (67% vs 97%, P = .01) were lower in patients with IgAN. Conclusions: Concurrent IgAN was not rare in anti-GBM disease. Patients showed milder kidney lesions and better recovery after immunosuppressive therapies. This might be partly explained by lower prevalence of anti-GBM IgG1 and IgG3 in these patients.

Urinary Modified C-Reactive Protein is Closely Associated with Tubulointerstitial Lesions in Lupus Nephritis.

Objective: Modified C-reactive protein (mCRP) is known to be involved in the upregulation and amplification of the local inflammatory response. This study investigated the circulating and local levels of mCRP and their relevance to clinicopathological features in patients with lupus nephritis. Methods: Ninety-five patients with renal biopsy-proven lupus nephritis and 30 normal controls were enrolled in this study. Plasma and urinary mCRP were screened by enzyme-linked immunosorbent assay (ELISA). The renal deposition of mCRP was detected by immunohistochemistry and immunofluorescence staining. A human proximal tubular epithelial cell line (HK2 cells) was incubated with purified IgG from lupus nephritis, and the production of CRP by HK2 cells was further evaluated. Results: Plasma and urinary levels of mCRP increased significantly in patients with lupus nephritis compared with normal controls (P = 0.013, P < 0.001, respectively). The urinary mCRP levels were associated with interstitial inflammatory cell infiltration (r = 0.514, P < 0.001) and interstitial fibrosis (r = 0.270, P = 0.008). The ROC-AUC of the urinary mCRP levels for diagnosing tubulointerstitial lesions was 0.766. The urinary mCRP levels were closely associated with poor outcomes (HR: 1.204, 95% CI: 1.029-1.409, P = 0.020). However, no correlations were found of the plasma mCRP levels with clinicopathological data or the prognosis of lupus nephritis. CRP was mostly deposited in the renal tubules in patients with lupus nephritis, and the expression of CRP was significantly correlated with tubulointerstitial lesion indices. Immunofluorescence staining showed that mCRP could colocalize with IgG in tubules. Lupus nephritis-derived IgG could induce CRP production by HK2 cells. Conclusion: Urinary mCRP levels were significantly increased, and urinary mCRP might be a biomarker for tubulointerstitial lesions in patients with lupus nephritis. Renal CRP could be produced by tubular epithelial cells after stimulation by lupus nephritis-derived IgG, and the local presence of mCRP might play a critical role in the development of tubulointerstitial lesions.

Clinicopathological and immunological features of new onset kidney disease: a rare event after SARS-CoV-2 vaccination.

The onset of various kidney diseases has been reported after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. However, detailed clinical and pathological features are lacking. We screened and analyzed patients with newly diagnosed kidney diseases after inactivated SARS-CoV-2 vaccination in Peking University First Hospital from January 2021 to August 2021, and compared them with the reported cases in the literature. We obtained samples of blood, urine and renal biopsy tissues. Clinical and laboratory information, as well as light microscopy, immunostaining and ultrastructural observations, were described. The SARS-CoV-2 spike protein and nucleoprotein were stained using the immunofluorescence technique in the kidney biopsy samples. SARS-CoV-2 specific antibodies were tested using magnetic particle chemiluminescence immunoassay. The study group included 17 patients with a range of conditions including immune-complex-mediated kidney diseases (IgA nephropathy, membranous nephropathy and lupus nephritis), podocytopathy (minimal change disease and focal segmental glomerulosclerosis) and others (antineutrophil-cytoplasmic-antibody-associated vasculitis, anti-glomerular basement membrane nephritis, acute tubulointerstitial nephritis and thrombotic microangiopathy). Seven patients (41.18%) developed renal disease after the first dose and ten (58.82%) after the second dose. The kidney disease spectrum as well as clinicopathological features are similar across different types of SARS-CoV-2 vaccines. We found no definitive evidence of SARS-CoV-2 spike protein or nucleoprotein deposition in the kidney biopsy samples. Seropositive markers implicated abnormal immune responses in predisposed individuals. Treatment and follow-up (median = 86 days) showed that biopsy diagnosis informed treatment and prognosis in all patients. In conclusion, we observed various kidney diseases following SARS-CoV-2 vaccine administration, which show a high consistency across different types of SARS-CoV-2 vaccines. Our findings provide evidence against direct vaccine protein deposition as the major pathomechanism, but implicate abnormal immune responses in predisposed individuals. These findings expand our understanding of SARS-CoV-2 vaccine renal safety.

Clinical and pathological characteristics of DKD patients with early-onset type 2 diabetes.

AIMS: In diabetic kidney disease (DKD) patients, early-onset T2DM effects on renal disease severity and outcomes remain uncertain. Herein, we aim to investigate the clinicopathological characteristics and renal outcomes in DKD patients with early-onset T2DM. METHODS: 489 patients with T2DM and DKD were retrospectively recruited and classified as having early (age at onset of T2DM < 40 years) and late (age at onset of T2DM ≥ 40 years) T2DM onset, analyzing the clinical and histopathological data. The predictive value of early-onset T2DM to renal outcomes in DKD patients was analyzed by Cox's regression. RESULTS: Among 489 DKD patients, 142 and 347 were classified as early and late T2DM onset, respectively. Early-onset T2DM patients exhibited worse glycaemic control (7.36 % ± 1.80 % vs. 6.86 % ± 1.57 %, P = 0.007) and more severe proteinuria (3.69 [1.55 to 7.03] vs. 1.81 [0.50 to 4.33] g/24 h, P < 0.001). Those with early-onset T2DM presented more severe glomerular lesions. In univariable Cox regression, early-onset T2DM showed a significant correlation with renal composite endpoint (HR [95%CI]: 0.56 [0.43 to 0.73], P < 0.001). However, after adjusting for potential confounders, early-onset T2DM was not independently correlated with renal composite endpoint (HR [95%CI]: 0.74 [0.46 to 1.21], P = 0.232). CONCLUSIONS: In DKD patients with early-onset T2DM, renal clinicopathological manifestations were severe. Age at onset in T2DM was significantly correlated with eGFR slope (r = 0.211, P < 0.001).

Determinants on urinary excretion of oxalate and other key factors related to urolithiasis among patients with chronic kidney disease: a single center study.

PURPOSE: Urolithiasis is a known risk factor for chronic kidney disease (CKD). However, how CKD might affect the risk of incidence of urolithiasis is not widely studied. METHODS: Urinary excretion of oxalate as well as other key factors related to urolithiasis was analyzed in a single center study of 572 patients with biopsy-proven kidney disease. RESULTS: The mean age of the cohort was 44.9 years and 60% were males. The mean eGFR was 65.9 ml/min/1.73 m2. Median urinary excretion of oxalate was 14.7 (10.4-19.1) mg/24-h and associated with current urolithiasis (OR 12.744, 95% CI: 1.564-103.873 per one logarithm transformed unit of urinary oxalate excretion). Oxalate excretion was not associated with eGFR and urinary protein excretion. Oxalate excretion was higher in patients with ischemia nephropathy as compared with patients with glomerular nephropathy and tubulointerstitial nephropathy (16.4 vs 14.8 vs 12.0 mg, p = 0.018). And ischemia nephropathy (p = 0.027) was associated with urinary oxalate excretion on adjusted linear regression analysis. Urinary excretion of calcium and uric acid was correlated with eGFR and urinary protein excretion (all p < 0.001), with ischemia nephropathy and tubulointerstitial nephropathy associated with uric acid excretion (both p < 0.01) as well. Citrate excretion was correlated with eGFR (p < 0.001) on adjusted linear regression. CONCLUSION: Excretion of oxalate and other key factors related to urolithiasis was differentially associated with eGFR, urinary protein, and pathological changes in CKD patients. The influence of these intrinsic traits of the underlining kidney disease should be considered when evaluating urolithiasis risk in patients with CKD.

Combination of anti-C1qA08 and anti-mCRP a.a.35-47 antibodies is associated with renal prognosis of patients with lupus nephritis.

Objective: The aim of this study is to explore the prevalence and clinicopathological associations between anti-C1qA08 antibodies and anti-monomeric CRP (mCRP) a.a.35-47 antibodies and to explore the interaction between C1q and mCRP. Methods: Ninety patients with biopsy-proven lupus nephritis were included from a Chinese cohort. Plasma samples collected on the day of renal biopsy were tested for anti-C1qA08 antibodies and anti-mCRP a.a.35-47 antibodies. The associations between these two autoantibodies and clinicopathologic features and long-term prognosis were analyzed. The interaction between C1q and mCRP was further investigated by ELISA, and the key linear epitopes of the combination of cholesterol binding sequence (CBS; a.a.35-47) and C1qA08 were tested by competitive inhibition assays. The surface plasmon resonance (SPR) was used to further verify the results. Results: The prevalence of anti-C1qA08 antibodies and anti-mCRP a.a.35-47 antibodies were 50/90 (61.1%) and 45/90 (50.0%), respectively. Levels of anti-C1qA08 antibodies and anti-mCRP a.a.35-47 antibodies were negatively correlated with serum C3 concentrations ((0.5(0.22-1.19) g/L vs. 0.39(0.15-1.38) g/L, P=0.002) and (0.48(0.44-0.88) g/L vs. 0.41(0.15-1.38) g/L, P=0.028), respectively. Levels of anti-C1qA08 antibodies were correlated with the score of fibrous crescents and tubular atrophy (r=-0.256, P=0.014 and r=-0.25, P=0.016, respectively). The patients with double positive antibodies showed worse renal prognosis than that of the double negative group (HR 0.899 (95% CI: 0.739-1.059), P=0.0336). The binding of mCRP to C1q was confirmed by ELISA. The key linear epitopes of the combination were a.a.35-47 and C1qA08, which were confirmed by competitive inhibition experiments and SPR. Conclusion: The combination of anti-C1qA08 and anti-mCRP a.a.35-47 autoantibodies could predict a poor renal outcome. The key linear epitopes of the combination of C1q and mCRP were C1qA08 and a.a.35-47. A08 was an important epitope for the classical pathway complement activation and a.a.35-47 could inhibit this process.

A modified renal risk score for Chinese patients with antineutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: The renal risk score (RRS) is a useful tool to predict end-stage renal disease (ESRD) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The current study aimed to validate the predictive performance of RRS and to further modify this model in Chinese AAV patients. METHODS: Two hundred and seventy-two patients diagnosed with AAV confirmed by renal biopsies were retrospectively enrolled from a single center. The RRS was calculated based on 3 categorical variables, i.e., the proportion of normal glomeruli, the proportion of interstitial fibrosis and tubular atrophy (IF/TA), and eGFR at biopsy, classifying these patients into low-, medium-, and high-risk groups. In addition, a modified model was developed based on the RRS and was further validated in another independent cohort of 117 AAV patients. The predictive performance of each model was evaluated according to discrimination and calibration. RESULTS: Patients were classified by the RRS into low- (26.5%), medium- (46.7%), and high-risk (26.8%) groups, with 120-month renal survival rates of 93.3%, 57.2%, and 18.4%, respectively (P < 0.001). The RRS showed good discrimination but less satisfactory calibration. Therefore, a modified model with improved discrimination and calibration was developed in Chinese AAV patients, with eGFR, proportion of normal glomeruli (both as continuous variables), and IF/TA (< 25%, 25-50%, > 50%) included. Internal and external validation of the modified model were performed. Finally, an online risk prediction tool was developed based on the modified model. CONCLUSIONS: The RRS was an independent predictor of ESRD of AAV patients. The modified model could predict the probability of ESRD for AAV patients with improved performance in Chinese AAV patients.

Trends of Urolithiasis in China: A National Study Based on Hospitalized Patients from 2013 to 2018.

Introduction: The aim of this study was to explore the chronological trends in clinical features and utilization of healthcare resources for hospitalized patients with urolithiasis in China. Methods: Patients with urolithiasis were extracted from the Hospital Quality Monitoring System, a national database of hospitalized patients in China, based on the International Classification of Diseases, Tenth Revision, codes. Variables including demographic characteristics, comorbidities, treatment modalities for urolithiasis, length of hospital stay, and expenditures were collected and analyzed. Results: Among 79.8 million hospitalized patients, 3.5 million were diagnosed with urolithiasis with an increasing trend (from 3.0% in 2013 to 4.0% in 2018). Most of these patients had upper urinary tract calculi (76.6% in 2013 and 81.7% in 2018). Middle-aged patients (46-65 years) constituted the largest proportion with a stable trend (from 46.9% in 2013 to 48.8% in 2018), while the proportion of older patients (>65 years) showed an increasing trend (from 23.7% in 2013 to 27.4% in 2018). The percentages of gout/hyperuricemia, hypertension, diabetes, and cardiovascular disease among the hospitalized patients with urolithiasis increased steadily, with the sharpest increases in patients from rural areas. Overall, 656,952 patients (18.9%) received surgical interventions for urolithiasis. The proportions of ureteroscopy and extracorporeal shockwave lithotripsy increased steadily during the 6-year study period, with simultaneous decreases in open surgery and percutaneous nephrolithotomy. The median length of hospital stay decreased from 10 days to 8 days. The cost of urolithiasis intervention accounted for 2.0% of the total hospitalization fee in 2013 and increased to 2.7% in 2018. Conclusions: The analysis showed an increasing trend in the percentage of hospitalized patients with urolithiasis, accompanied by an increased percentage of the total hospitalization fee for urolithiasis intervention during the 6-year study period. Based on the increasing trends in the proportion of older patients (>65 years) and percentages of metabolic comorbidities among patients with urolithiasis, an increased burden of urolithiasis on the healthcare system in China is anticipated.