Clinicopathological features and outcomes of PLA2R-related membranous nephropathy with renal glycosuria.

BACKGROUND: Membranous nephropathy (MN) is an immune complex-mediated disease. Massive proteinuria can lead to Fanconi syndrome, clinically manifesting as renal glycosuria. The prevalence and prognosis of M-type phospholipase A2 receptor (PLA2R)-related MN with renal glycosuria remain unknown. MATERIALS AND METHODS: Patients diagnosed with PLA2R-related MN with renal glycosuria were reviewed, and the control group comprised patients with MN without renal glycosuria who were randomly selected at a ratio of 1 : 3. RESULTS: 50 patients diagnosed with PLA2R-related MN with renal glycosuria from January 2015 to January 2020 were included, with a prevalence of 2.3%. Compared with patients without renal glycosuria, those with renal glycosuria exhibited greater proteinuria, lower estimated glomerular filtration rate (eGFR), and higher use of diuretics, anticoagulants, antibiotics, traditional Chinese medicine, and tacrolimus within 3 months prior to renal biopsy (all p < 0.05). Histologically, patients with renal glycosuria exhibited more severe pathological stages, acute/chronic tubulointerstitial lesions, and tubulointerstitial inflammation (all p < 0.05). Of the 10 patients treated with rituximab (RTX), proteinuria remission was maintained in 6 (60%) patients, and urine glucose remission was achieved in 5 of these 6 patients (83.3%). Multivariate Cox regression analysis showed that renal glycosuria and age > 50 years were independent risk factors for end-stage renal disease (ESRD) or a 30% reduction in the eGFR in patients with PLA2R-related MN. CONCLUSION: PLA2R-related MN patients with renal glycosuria presented with more severe clinicopathological manifestations and worse prognoses. Nephrotoxic drugs should be administered rationally, and RTX should be considered as a promising treatment option.

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.

Role of TSP-1 and its receptor ITGB3 in the renal tubulointerstitial injury of focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS), a common cause of primary glomerulonephritis, has a poor prognosis and is pathologically featured by tubulointerstitial injury. Thrombospondin-1 (TSP-1) is an extracellular matrix protein that acts in combination with different receptors in the kidney. Here, we analyzed the tubular expression of TSP-1 and its receptor integrin ß3 (ITGB3) in FSGS. Previously the renal interstitial chip analysis of FSGS patients with tubular interstitial injury showed that the expression of TSP-1 and ITGB3 were upregulated. We found that the expression of TSP-1 and ITGB3 increased in the tubular cells of FSGS patients. The plasma level of TSP-1 increased and was correlated to the degree of tubulointerstitial lesions in FSGS patients. TSP-1/ITGB3 signaling induced renal tubular injury in HK-2 cells exposure to bovine serum albumin and the adriamycin (ADR)-induced nephropathy model. THBS1 KO ameliorated tubular injury and renal fibrosis in ADR-treated mice. THBS1 knockdown decreased the expression of KIM-1 and caspase 3 in the HK-2 cells treated with bovine serum albumin, while THBS1 overexpression could induce tubular injury. In vivo, we identified cyclo-RGDfK as an agent to block the binding of TSP-1 to ITGB3. Cyclo-RGDfK treatment could alleviate ADR-induced renal tubular injury and interstitial fibrosis in mice. Moreover, TSP-1 and ITGB3 were colocalized in tubular cells of FSGS patients and ADR-treated mice. Taken together, our data showed that TSP-1/ITGB3 signaling contributed to the development of renal tubulointerstitial injury in FSGS, potentially identifying a new therapeutic target for FSGS.

Risk factors for acute kidney injury and kidney relapse in patients with lupus podocytopathy.

Background: Patients with lupus podocytopathy show a high incidence of acute kidney injury (AKI) and relapse, but the risk factors and mechanisms were unclear. This study analysed the clinicopathological features and risk factors for AKI and relapse in lupus podocytopathy patients. Methods: The cohort of lupus podocytopathy was generated by screening the biopsies of patients with lupus nephritis (LN) from 2002 to 2022 and was divided into the mild glomerular lesion (MGL) and focal segmental glomerulosclerosis (FSGS) groups based on glomerular morphological characteristics. The acute (ATI) and chronic (CTI) tubulointerstitial lesions were semi-quantitatively scored. Logistic and Cox regressions were employed to identify the risk factors for AKI and relapse, respectively. Results: Among 6052 LN cases, 98 (1.6%) were diagnosed as lupus podocytopathy, with 71 in the MGL group and 27 in the FSGS group. All patients presented with nephrotic syndrome and 33 (34.7%) of them had AKI. Seventy-seven (78.6%) patients achieved complete renal response (CRR) within 12 weeks of induction treatment, in which there was no difference in the CRR rate between glucocorticoid monotherapy and combination therapy with glucocorticoids plus immunosuppressants. Compared with the MGL group, patients in the FSGS group had significantly higher incidences of hypertension and haematuria; in addition, they had higher Systemic Lupus Erythematosus Disease Activity Index 2000, ATI and CTI scores but a significantly lower CRR rate. Urinary protein ≥7.0 g/24 h and serum C3 ≤0.750 g/l were independent risk factors for AKI. During a median follow-up of 78 months, 57 cases (60.0%) had relapse and none reached the kidney endpoint. Failure to achieve CRR within 12 weeks, maintenance with glucocorticoid monotherapy and AKI at onset were independent risk factors for kidney relapse. Conclusions: In this study, histological subtypes of lupus podocytopathy were found to be associated with clinical features and treatment response. In addition, several risk factors associated with AKI occurrence and kidney relapse were identified.

Clinicopathological Characteristics of Light and Heavy Chain Deposition Disease: A Case Series.

RATIONALE & OBJECTIVE: Light and heavy chain deposition disease (LHCDD) is a rare form of monoclonal immunoglobulin (Ig) deposition disease, and limited clinical data are available characterizing this condition. Here we describe the clinicopathological characteristics and outcomes of LHCDD. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 13 patients with biopsy-proven LHCDD diagnosed between January 2008 and December 2022 at one of 2 Chinese medical centers. FINDINGS: Among the 13 patients described, 6 were men and 7 were women, with a mean age of 52.6±8.0 years. Patients presented with hypertension (76.9%), anemia (84.6%), increased serum creatinine concentrations (84.6%; median, 1.7mg/dL), proteinuria (100%; average urine protein, 3.0g/24h), nephrotic syndrome (30.8%), and microscopic hematuria (76.9%). Serum immunofixation electrophoresis showed monoclonal Ig for 11 patients (84.6%). Serum free light chain ratios were abnormal in 11 patients (84.6%), and heavy/light chain ratios were abnormal in 9 of 10 patients (90%) with available data. Five patients were diagnosed with multiple myeloma. A histological diagnosis of nodular mesangial sclerosis was made in 10 patients (76.9%). Immunofluorescence demonstrated deposits of IgG subclass in 7 patients (γ-κ, n=4; γ-λ, n=3) and IgA in 5 patients (α-κ, n=2; α-λ, n=3). Six patients underwent IgG subclass staining (γ1, n=3; γ2, n=2; γ3, n=1). The deposits of IgD-κ were confirmed by mass spectrometry in 1 patient. Among 12 patients for whom data were available during a median of 26.5 months, 11 received chemotherapy and 1 received conservative treatment. One patient died, and disease progressed to kidney failure in 3 (25%). Among the 9 patients evaluable for hematological and kidney disease progression, 5 (56%) had a hematologic response and 1 (11%) exhibited improvement in kidney disease. LIMITATIONS: Retrospective descriptive study, limited number of patients, urine protein electrophoresis or immunofixation electrophoresis test results missing for most patients. CONCLUSIONS: In this case series of LHCDD, light and heavy chain deposition in kidney tissues were most frequent with monoclonal IgG1-κ. Among patients with evaluable data, more than half had a hematologic response, but a kidney response was uncommon.

Artificial intelligence assists identification and pathologic classification of glomerular lesions in patients with diabetic nephropathy.

BACKGROUND: Glomerular lesions are the main injuries of diabetic nephropathy (DN) and are used as a crucial index for pathologic classification. Manual quantification of these morphologic features currently used is semi-quantitative and time-consuming. Automatically quantifying glomerular morphologic features is urgently needed. METHODS: A series of convolutional neural networks (CNN) were designed to identify and classify glomerular morphologic features in DN patients. Associations of these digital features with pathologic classification and prognosis were further analyzed. RESULTS: Our CNN-based model achieved a 0.928 F1-score for global glomerulosclerosis and 0.953 F1-score for Kimmelstiel-Wilson lesion, further obtained a dice of 0.870 for the mesangial area and F1-score beyond 0.839 for three glomerular intrinsic cells. As the pathologic classes increased, mesangial cell numbers and mesangial area increased, and podocyte numbers decreased (p for all < 0.001), while endothelial cell numbers remained stable (p = 0.431). Glomeruli with Kimmelstiel-Wilson lesion showed more severe podocyte deletion compared to those without (p < 0.001). Furthermore, CNN-based classifications showed moderate agreement with pathologists-based classification, the kappa value between the CNN model 3 and pathologists reached 0.624 (ranging from 0.529 to 0.688, p < 0.001). Notably, CNN-based classifications obtained equivalent performance to pathologists-based classifications on predicting baseline and long-term renal function. CONCLUSION: Our CNN-based model is promising in assisting the identification and pathologic classification of glomerular lesions in DN patients.

Advancing the application of the analytical renal pathology system in allograft IgA nephropathy patients.

BACKGROUND: The analytical renal pathology system (ARPS) based on convolutional neural networks has been used successfully in native IgA nephropathy (IgAN) patients. Considering the similarity of pathologic features, we aim to evaluate the performance of the ARPS in allograft IgAN patients and broaden its implementation. METHODS: Biopsy-proven allograft IgAN patients from two different centers were enrolled for internal and external validation. We implemented the ARPS to identify glomerular lesions and intrinsic glomerular cells, and then evaluated its performance. Consistency between the ARPS and pathologists was assessed using intraclass correlation coefficients. The association of digital pathological features with clinical and pathological data was measured. Kaplan-Meier survival curve and cox proportional hazards model were applied to investigate prognosis prediction. RESULTS: A total of 56 biopsy-proven allograft IgAN patients from the internal center and 17 biopsy-proven allograft IgAN patients from the external center were enrolled in this study. The ARPS was successfully applied to identify the glomerular lesions (F1-score, 0.696-0.959) and quantify intrinsic glomerular cells (F1-score, 0.888-0.968) in allograft IgAN patients rapidly and precisely. Furthermore, the mesangial hypercellularity score was positively correlated with all mesangial metrics provided by ARPS [Spearman's correlation coefficient (r), 0.439-0.472, and all p values < 0.001]. Besides, a higher allograft survival was noticed among patients in the high-level groups of the maximum and ratio of endothelial cells, as well as the maximum and density of podocytes. CONCLUSION: We propose that the ARPS could be implemented in future clinical practice with outstanding capability.

Deep learning model to predict lupus nephritis renal flare based on dynamic multivariable time-series data.

OBJECTIVES: To develop an interpretable deep learning model of lupus nephritis (LN) relapse prediction based on dynamic multivariable time-series data. DESIGN: A single-centre, retrospective cohort study in China. SETTING: A Chinese central tertiary hospital. PARTICIPANTS: The cohort study consisted of 1694 LN patients who had been registered in the Nanjing Glomerulonephritis Registry at the National Clinical Research Center of Kidney Diseases, Jinling Hospital from January 1985 to December 2010. METHODS: We developed a deep learning algorithm to predict LN relapse that consists of 59 features, including demographic, clinical, immunological, pathological and therapeutic characteristics that were collected for baseline analysis. A total of 32 227 data points were collected by the sliding window method and randomly divided into training (80%), validation (10%) and testing sets (10%). We developed a deep learning algorithm-based interpretable multivariable long short-term memory model for LN relapse risk prediction considering censored time-series data based on a cohort of 1694 LN patients. A mixture attention mechanism was deployed to capture variable interactions at different time points for estimating the temporal importance of the variables. Model performance was assessed according to C-index (concordance index). RESULTS: The median follow-up time since remission was 4.1 (IQR, 1.7-6.7) years. The interpretable deep learning model based on dynamic multivariable time-series data achieved the best performance, with a C-index of 0.897, among models using only variables at the point of remission or time-variant variables. The importance of urinary protein, serum albumin and serum C3 showed time dependency in the model, that is, their contributions to the risk prediction increased over time. CONCLUSIONS: Deep learning algorithms can effectively learn through time-series data to develop a predictive model for LN relapse. The model provides accurate predictions of LN relapse for different renal disease stages, which could be used in clinical practice to guide physicians on the management of LN patients.

Docosahexaenoic acid (DHA) inhibits abdominal fat accumulation by promoting adipocyte apoptosis through PPARγ-LC3-BNIP3 pathway-mediated mitophagy.

Obesity has always been an overwhelming health concern worldwide. Docosahexaenoic acid (DHA) reduces abdominal fat accumulation by inducing adipocyte apoptosis, but the underlying mechanism remains unclear. Mitophagy, the process of maintaining mitochondrial homeostasis, has a double-edged sword effect that positively or negatively regulates apoptosis. In this study, grass carp (Ctenopharyngodon idellus) was used as an animal model to investigate the role of mitophagy in regulating apoptosis and the potential molecular mechanisms for DHA-induced mitophagy in vivo and in vitro. Firstly, we found that DHA induced the intrinsic apoptosis in grass carp adipocytes, accompanying by activating BNIP3/NIX-mediated mitophagy. Then, suppression of mitophagy alleviated apoptosis and eliminated the inhibition of lipid accumulation induced by DHA in vivo and in vitro. Mechanistically, the DHA-induced mitophagy was caused by activating PPARγ and its DNA binding capacity to the LC3 promoter, which promoted the interaction of BNIP3 (rather than NIX) with LC3. However, the inhibition of PPARγ in vitro significantly decreased the expression of autophagy-related genes (P < 0.05), reducing the colocalization of mitochondria and lysosomes while preventing BNIP3/NIX-mediated mitophagy-mediated apoptosis and subsequently alleviating the inhibition of lipid accumulation in adipocytes induced by DHA. For the first time, we demonstrated that DHA activates mitophagy by regulating the PPARγ-LC3-BNIP3 pathway, consequently inducing apoptosis, which decreases adipocytes, inhibiting lipid accumulation in grass carp. These findings provide new insight into the mechanism of DHA-induced apoptosis mediated by mitophagy as the potential therapeutic target of inhibiting abdominal fat accumulation in vertebrates.