The correlation between anti-phospholipase A2 receptor antibodies and hypercoagulability in patients with idiopathic membranous nephropathy.

BACKGROUND: Patients with idiopathic membranous nephropathy (IMN) are more likely to be complicated by venous thromboembolism (VTE). The aim of the study was to investigate the potential association between anti-phospholipase A2 receptor (PLA2R) antibodies and hypercoagulability in patients with IMN. METHODS: A total of 168 patients with biopsy-proven IMN and 36 patients with biopsy-proven minimal change disease (MCD) were enrolled in this study. The clinical data, serum anti-PLA2R antibodies and coagulation-related indices of the patients were retrospectively analyzed. RESULTS: Patients with IMN were categorized into glomerular PLA2R staining-positive (GAg+) IMN group and glomerular PLA2R staining-negative (GAg-) IMN group in the study. Patients with IMN who were GAg + had lower PT, APTT and R time than patients with IMN who were GAg-, while the CI value was higher in patients with IMN who were GAg+. Patients with IMN who were GAg + were divided into the SAb+/GAg + group and the SAb-/GAg + group. Patients with IMN who were SAb+/GAg + had higher Fib and MA values than patients with IMN who were SAb-/GAg+. Correlation analysis showed that serum anti-PLA2R antibodies were positively correlated with fibrinogen, D-dimer, K time, CI value, α-angle, and MA value. Multiple linear regression analysis indicated that anti-PLA2R antibodies were independently correlated with fibrinogen and MA value. CONCLUSION: Our study provides a new perspective on the underlying mechanisms of hypercoagulability in patients with IMN. Anti-PLA2R antibodies are associated with hypercoagulability in patients with IMN and may affect coagulation in patients with IMN by affecting platelet aggregation function and fibrinogen counts.

Renal Interstitial Inflammation Predicts Nephropathy Progression in IgA Nephropathy: A Two-Center Cohort Study.

INTRODUCTION: Renal interstitial inflammation often presents in immunoglobulin A nephropathy (IgAN), but its predictive role in kidney disease progression remains controversial. METHODS: This retrospective two-center cohort study included 1,420 adult IgAN patients between January 2003 and May 2018 followed for a median of approximately 7 years at two Chinese hospitals. The predictor was renal interstitial inflammation within the total cortical interstitium (none/mild [0-25%], moderate [26-50%], or severe [>50%]). For the further propensity score matching analyses, the participants with moderate and severe level of interstitial inflammation were pooled to match those with none/mild level of interstitial inflammation. The outcomes included the rate of kidney function decline, and the composite kidney endpoint event defined as a >40% reduction in the estimated glomerular filtration rate, end-stage kidney disease. Linear regression and Cox proportional hazards regression analyses were used to examine the association between interstitial inflammation and the outcomes. The predictive performance of the model also assessed using multivariate logistic regression analyses with the receiver operating characteristic curve analysis. Reclassification was assessed using the continuous net reclassification improvement and integrated discrimination improvement adapted for censoring for the assessment of the model with or without interstitial inflammation. RESULTS: For the check of reproducibility, the kappa statistic was 0.71, and intraclass correlation coefficient was 0.77. After adjustment for relating covariates, a higher level of interstitial inflammation was associated with a faster rate of kidney function decline (eGFR slope [mL/min/1.73 m2] of 1.34 [95% CI: -2.56 to 5.23], 3.50 [95% CI: -0.40 to 7.40], and 7.52 [95% CI: 3.02 to 12.01]) in the patients with none/mild, moderate, and severe interstitial inflammation, respectively, in the multivariable linear regression models and with an increased risk of kidney disease progression (HR for moderate vs. none/mild, 1.85; 95% CI: 1.10-3.13; HR for severe vs. none/mild, 2.95; 95% CI: 1.52-5.73) in the multivariable Cox proportional hazards models. Analyses in the propensity score-matched cohort, subgroups, and the sensitive analyses yielded consistent results. The receiver operating curves indicated a higher area under the curve of 0.83 in the model with interstitial inflammation compared with 0.81 in that without interstitial inflammation. In addition, incorporating interstitial inflammation into the International IgAN Risk Prediction Tool improved the diagnostic power of the algorithm to predict risk of progression. CONCLUSION: Interstitial inflammation is a reproducible pathologic parameter that may be adopted as a predictor for kidney disease progression in patients with IgAN.

The Association of Low Hemoglobin Levels with IgA Nephropathy Progression: A Two-Center Cohort Study of 1,828 Cases.

AIM: To investigate the relationship between hemoglobin levels and the progression of IgA nephropathy (IgAN). METHODS: In a two-center cohort of 1,828 cases with biopsy-proven IgAN, we examined the association of hemoglobin levels with the primary outcome of a composite of all-cause mortality or kidney failure defined as a 40% decline in eGFR, or ESKD (defined as eGFR <15 mL/min/1.73 m2 or need for kidney replacement therapy including hemodialysis, peritoneal dialysis, or kidney transplantation), or the outcome of kidney failure, assessed using Cox and logistic regression models, respectively, with adjustment for confounders. RESULTS: At baseline, mean age, eGFR, and hemoglobin levels were 33.75 ± 11.03 years, 99.70 ± 30.40 mL/min/1.73 m2, and 123.47 ± 18.36 g/L, respectively. During a median of approximately 7-year follow-up, 183 cases reached the composite outcome. After adjustment for demographic and IgAN-specific covariates and treatments, a lower quartile of hemoglobin was nonlinearly associated with an increased risk of the primary outcome or kidney failure in the Cox proportional hazards models (primary outcome: HR for quartile 3 vs. 4, 1.37; 95% CI, 0.83-2.25; HR for quartile 2 vs. 4, 1.18; 95% CI, 0.68-2.07; HR for quartile 1 vs. 4, 1.91; 95% CI, 1.15-3.17; kidney failure: HR for quartile 3 vs. 4, 1.39; 95% CI, 0.84-2.31; HR for quartile 2 vs. 4, 1.20; 95% CI, 0.68-2.11; HR for quartile 1 vs. 4, 1.83; 95% CI, 1.09-3.07) in the fully adjusted model. Then, hemoglobin levels were transformed to a binary variable for fitting the model according to the criteria for anemia of 110 g/L in the women and 120 g/L in men in China. The participants in the anemia group had an increased risk of developing outcomes compared with the nonanemia group in both genders (primary outcome: male: HR, 1.64; 95% CI, 1.01-2.68; female: HR, 1.68; 95% CI, 1.02-2.76; kidney failure: male: HR, 1.60; 95% CI, 0.97-2.64; female: HR, 1.58; 95% CI, 0.95-2.61) in the fully adjusted model. CONCLUSIONS: A low level of hemoglobin was nonlinearly associated with IgAN progression. The anemic IgAN patients presented a higher risk of developing poor outcomes compared with the nonanemic patients.

The evolution of morphological variants of focal segmental glomerulosclerosis: a repeat biopsy-based observation.

BACKGROUND: The Columbia classification employs a systematic, hierarchical approach to define five mutually exclusive variants. Studies have demonstrated differences in baseline clinical characteristics and outcomes among the Columbia classification variants. However, the evolution of the Columbia classification variants of primary focal segmental glomerulosclerosis (FSGS) is unclear. We assessed the evolution of morphological variants in FSGS based on repeat native renal biopsies. METHODS: Twenty-four patients (18 male, 6 female) with idiopathic FSGS who underwent more than one renal biopsy were enrolled in this study; three of these patients underwent three renal biopsies. The patients' clinicopathological features were reviewed. The subtypes of FSGS (2004 Columbia classification) included the collapsing, tip, cellular, perihilar and not otherwise specified (NOS) variants. The evolution of the Columbia classification variants of primary FSGS in each patient was evaluated. RESULTS: The interval between the first and second renal biopsy was 21.95 ± 24.33 months. No significant differences in laboratory data were noted between the first and second renal biopsy. At the first renal biopsy, 5 patients were classified with collapsing, 5 with tip, 6 with cellular, 2 with perihilar and 6 with NOS variants. At the second renal biopsy, 3 patients were classified with collapsing, 3 with tip lesion, 4 with cellular, 1 with perihilar and 13 with NOS variants. Subtype changes from the first to repeat biopsies occurred in 11 patients, 9 of which progressed from other variants to the NOS variant. CONCLUSION: Repeat renal biopsies are a useful tool for observing FSGS histological changes. The transformation from other subtypes to the NOS variant was the most common change; these alterations were accompanied by clinical progression.

Relationship between serum soluble urokinase plasminogen activator receptor level and steroid responsiveness in FSGS.

BACKGROUND AND OBJECTIVES: Soluble urokinase plasminogen activator receptor (suPAR) was initially proposed as a pathogenic and predictive biomarker of primary FSGS, but the findings were controversial. This study aimed to clarify the clinical implications of suPAR. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The study enrolled 109 patients with biopsy-proven primary FSGS who were administered prednisone between January 2011 and May 2013 and followed up for 6-24 months (median duration of follow-up, 12 months). Ninety-six healthy volunteers, 20 patients with minimal-change disease (MCD), and 22 patients with membranous nephropathy (MN) served as controls. Serum suPAR levels were measured using ELISA. RESULTS: suPAR levels in patients with FSGS (median, 3512 [interquartile range (IQR), 2232-4231] pg/ml) were significantly higher than in healthy controls (median, 1823 [IQR, 1563-2212] pg/ml; P<0.001), patients with MCD (median, 1678 [IQR, 1476-2182] pg/ml; P<0.001), and patients with MN (median, 1668 [IQR, 1327-2127] pg/ml; P<0.001). With 3000 pg/ml used as a threshold, suPAR levels were elevated in 48.6% of patients with FSGS, in contrast to 5% of patients with MCD and 4.5% of those with MN. suPAR levels were independently associated with steroid response in patients with FSGS (odds ratio, 85.02; P=0.001). Patients who were sensitive to steroids had significantly higher suPAR levels than nonsensitive patients (median, 3426 [IQR, 2670-5655] pg/ml versus 2523 [IQR, 1977-3460] pg/ml; P=0.001). A suPAR level of 3400 pg/ml was chosen as the optimal cutoff value for steroid response. At the 6-month follow-up in 84 patients with FSGS, suPAR levels were significantly decreased in those with suPAR level ≥ 3400 pg/ml (median, 4553 [IQR, 3771-6120] pg/ml versus 3149 [IQR, 2278-3953]; P=0.002) but were unchanged in patients with suPAR level <3400 pg/ml (median, 2359 [IQR, 2023-2842] pg/ml versus 2490 [IQR, 1916-3623] pg/ml; P=0.09). CONCLUSIONS: suPAR is specifically elevated in some patients with FSGS, which differs from the finding in patients with MCD and MN. A suPAR assay may help predict steroid response in patients with primary FSGS.

Podocyte autophagic activity plays a protective role in renal injury and delays the progression of podocytopathies.

The progression of podocytopathies is quite variable among patients and the underlying reason for this remains unclear. Here, we report that autophagic activity in podocytes plays a critical role in controlling the progression of podocytopathies. Morphological and biochemical studies on renal biopsies from patients with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS) showed that glomeruli, and in particular podocytes, from MCD patients had higher levels of Beclin1-mediated autophagic activity than glomeruli from FSGS patients. Repeat renal biopsies of MCD patients enabled tracking of podocyte autophagic activity and confirmed that patients maintaining high podocyte autophagic activity retained MCD status, whereas patients with decreased podocyte autophagic activity progressed to FSGS. Inhibition of autophagic activity, by knocking down Beclin1 or by treating with 3-methyladenine (3-MA) or chloroquine, enhanced puromycin aminonucleoside (PAN)-induced apoptosis of podocytes. In contrast, rapamycin-mediated promotion of autophagic activity decreased this apoptosis. In PAN-treated rats, inhibition of autophagy with 3-MA or chloroquine resulted in earlier onset and greater proteinuria, more extensive foot-process effacement, and reduction in podocyte markers, whereas rapamycin-mediated stimulation of autophagy led to decreased proteinuria and less severe foot-process effacement, but higher expression of podocyte markers. This study demonstrates that podocyte autophagic activity plays a critical protective role in renal injury and that maintaining podocyte autophagic activity represents a potential therapeutic strategy for controlling the progression of podocytopathies.