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 expressions of TSP-1 and ITGB3 were up-regulated. We found that the level of TSP-1 and ITGB3 increased in the tubular cells of FSGS patients. The serum level of TSP-1 increased and was correlated to the degree of tubulointerstitial lesions in FSGS patients. THBS1/ITGB3 signaling induced renal tubular injury in HK-2 cells exposure to BSA and the ADR-induced nephropathy model. THBS1 knockout 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 BSA, 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.

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.

Establishing a human-induced pluripotent stem cell line (SMUSHi003-A) from a patient with Charcot-Marie-Tooth disease and focal segmental glomerulosclerosis.

INF2 mutations cause Charcot-Marie-Tooth disease (CMT), and /or focal segmental glomerulosclerosis (FSGS) in an autosomal dominant inheritance mode, whose underlying mechanism remainsunclear. Here, we report the generation of an iPSC line from a female patient with CMT and FSGS. The iPSC line from the patient's PBMCscarried aheterozygous INF2 deletion mutation (c.315_323delGCGCGCCGT) within the conserved E2. This line exhibited a normal karyotype, high expression of pluripotency markers, and trilineage differentiation potential. This line can be used to dissect the complex pathomechanism through further induction of differentiation into related cells and as a drug screening tool for INF2-associated diseases.

Peroxiredoxin 1 aggravates acute kidney injury by promoting inflammation through Mincle/Syk/NF-κB signaling.

Damage-associated molecular patterns (DAMPs) are a cause of acute kidney injury (AKI). Our knowledge of these DAMPs remains incomplete. Here, we report serum peroxiredoxin 1 (Prdx1) as a novel DAMP for AKI. Lipopolysaccharide (LPS) and kidney ischemia/reperfusion injury instigated AKI with concurrent increases in serum Prdx1 and reductions of Prdx1 expression in kidney tubular epithelial cells. Genetic knockout of Prdx1 or use of a Prdx1-neutralizing antibody protected mice from AKI and this protection was impaired by introduction of recombinant Prdx1 (rPrdx1). Mechanistically, lipopolysaccharide increased serum and kidney proinflammatory cytokines, macrophage infiltration, and the content of M1 macrophages. All these events were suppressed in Prdx1-/- mice and renewed upon introduction of rPrdx1. In primary peritoneal macrophages, rPrdx1 induced M1 polarization, activated macrophage-inducible C-type lectin (Mincle) signaling, and enhanced proinflammatory cytokine production. Prdx1 interacted with Mincle to initiate acute kidney inflammation. Of note, rPrdx1 upregulated Mincle and the spleen tyrosine kinase Syk system in the primary peritoneal macrophages, while knockdown of Mincle abolished the increase in activated Syk. Additionally, rPrdx1 treatment enhanced the downstream events of Syk, including transcription factor NF-κB signaling pathways. Furthermore, serum Prdx1 was found to be increased in patients with AKI; the increase of which was associated with kidney function decline and inflammatory biomarkers in patient serum. Thus, kidney-derived serum Prdx1 contributes to AKI at least in part by activating Mincle signaling and downstream pathways.

The Spectrum of Biopsy-Proven Kidney Diseases, Causes, and Renal Outcomes in Acute Kidney Injury Patients.

INTRODUCTION: Acute kidney injury (AKI) is a group of highly heterogeneous, complicated clinical syndromes. Although kidney biopsy plays an irreplaceable role in evaluating complex AKI, a few studies have focused on the clinicopathology of AKI biopsies. This study analyzed the pathological disease spectrum, causes, and renal outcomes of biopsied AKI patients. METHODS: We retrospectively included 2,027 AKI patients who underwent kidney biopsies at a national clinical research center of kidney diseases from 2013 through 2018. To compare the biopsied AKI cases without and with coexisting glomerulopathy, patients were classified into acute tubular/tubulointerstitial nephropathy-associated AKI (ATIN-AKI) and glomerular disease-associated AKI (GD-AKI) groups. RESULTS: Of 2,027 biopsied AKI patients, 65.1% were male, with a median age of 43 years. A total of 1,590 (78.4%) patients had coexisting GD, while only 437 (21.6%) patients had ATIN alone. The AKI patients with GD mainly (53.5%) manifested as stage 1 AKI, while most ATIN-AKI patients (74.8%) had stage 3 AKI. In the ATIN-AKI group, 256 (58.6%) patients had acute interstitial nephritis (AIN), and 77 (17.6%) had acute tubular injury (ATI). ATIN-AKI was mainly caused by drugs in 85.5% of AIN and 63.6% of ATI cases, respectively. In AKI patients with coexisting GD, the leading pathological diagnoses in over 80% of patients were IgA nephropathy (IgAN, 22.5%), minimal change disease (MCD, 17.5%), focal segmental glomerulosclerosis (FSGS, 15.3%), lupus nephritis (LN, 11.9%), membranous nephropathy (MN, 10.2%), and ANCA-associated vasculitis (AAV, 4.7%). A total of 775 patients were followed up within 3 months after renal biopsy; ATIN-AKI patients achieved statistically higher complete renal recovery than the GD-AKI patients (83.5% vs. 70.5%, p < 0.001). CONCLUSIONS: Most biopsied AKI patients have coexisting GD, while ATIN alone is seen less frequently. ATIN-AKI is mainly caused by drugs. In GD-AKI patients, IgAN, MCD, FSGS, LN, MN, and AAV are the leading diagnoses. Compared to AKI patients without GD, patients with GD suffer from worse renal function recovery.

Clinical Acute Kidney Injury and Histologic Acute Tubular-Interstitial Injury and Their Prognosis in Diabetic Nephropathy.

INTRODUCTION: Histologic acute tubular-interstitial injury (hATI) is often observed in patients with diabetic nephropathy (DN). This study aimed to determine the relationship between hATI and clinical acute kidney injury (cAKI) and evaluate significance of hATI in patients with DN. METHODS: Patients with biopsy-proven DN through 2003-2018 in our center were selected. The prevalence of hATI and its correlations with cAKI, tubular injury biomarkers, and serum creatinine were investigated. The renal survival rates and prognostic factors were analyzed by Kaplan-Meier curve and Cox regression model, respectively. RESULTS: Of 1,414 patients with DN, 70.4% were male, with a median age of 50.0 years. The incidences of cAKI and hATI were 8.6% and 57.8%, respectively. The severities of most hATI were mild (91.0%). The incidence of cAKI in those with hATI was only 12.2%. The incidences of cAKI positively correlated with the scores of hATI (Kendall r = 0.273, p < 0.001). The presence of hATI was related to rapid creatinine rise and increased tubular injury biomarkers although without cAKI. After adjusting for significant covariates, multivariate Cox models showed that patients with hATI alone were one and a half times more likely to develop ESRD (hazard ratio [HR]: 1.46; 95% CI, 1.05-2.02) than those without hATI or cAKI, and patients with hATI plus cAKI were 3 times more likely to develop ESRD (HR: 2.96; 95% CI, 1.85-4.72). CONCLUSION: Our findings indicated that hATI was common in patients with DN where the majorities were mild hATI and without cAKI. hATI was an independent risk factor of DN progression, regardless of episodes of cAKI.

Identification of glomerular lesions and intrinsic glomerular cell types in kidney diseases via deep learning.

Identification of glomerular lesions and structures is a key point for pathological diagnosis, treatment instructions, and prognosis evaluation in kidney diseases. These time-consuming tasks require a more accurate and reproducible quantitative analysis method. We established derivation and validation cohorts composed of 400 Chinese patients with immunoglobulin A nephropathy (IgAN) retrospectively. Deep convolutional neural networks and biomedical image processing algorithms were implemented to locate glomeruli, identify glomerular lesions (global and segmental glomerular sclerosis, crescent, and none of the above), identify and quantify different intrinsic glomerular cells, and assess a network-based mesangial hypercellularity score in periodic acid-Schiff (PAS)-stained slides. Our framework achieved 93.1% average precision and 94.9% average recall for location of glomeruli, and a total Cohen's kappa of 0.912 [95% confidence interval (CI), 0.892-0.932] for glomerular lesion classification. The evaluation of global, segmental glomerular sclerosis, and crescents achieved Cohen's kappa values of 1.0, 0.776, 0.861, and 95% CI of (1.0, 1.0), (0.727, 0.825), (0.824, 0.898), respectively. The well-designed neural network can identify three kinds of intrinsic glomerular cells with 92.2% accuracy, surpassing the about 5-11% average accuracy of junior pathologists. Statistical interpretation shows that there was a significant difference (P value < 0.0001) between this analytic renal pathology system (ARPS) and four junior pathologists for identifying mesangial and endothelial cells, while that for podocytes was similar, with P value = 0.0602. In addition, this study indicated that the ratio of mesangial cells, endothelial cells, and podocytes within glomeruli from IgAN was 0.41:0.36:0.23, and the performance of mesangial score assessment reached a Cohen's kappa of 0.42 and 95% CI (0.18, 0.69). The proposed computer-aided diagnosis system has feasibility for quantitative analysis and auxiliary recognition of glomerular pathological features. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Clinical features and prognosis analysis of 57 patients with primary tracheal tumors.

BACKGROUND: Primary tracheal tumor (PTT) is a rare disease with poor prognosis. Its clinical features are variable. Treatment strategies for patients with PTTs are not standardized. The purpose of this study was to explore the clinical features, management and prognosis of PTT. METHODS: From 2009 to 2019, 57 patients were diagnosed with PTTs at Xiangya Hospital, China. A retrospective review of their medical records was performed. RESULTS: Among the 57 patients, 8 (14.0%) had benign tumors and 49 (86.0%) had malignant. Squamous cell carcinoma (SCC) (n=20, 40.8%) and adenoid cystic carcinoma (ACC) (n=10, 20.4%) were the most common histologic types. Seven (87.5%) of the benign PTT patients underwent bronchoscopic intervention and had no further complications. The 5-year survival rate for malignant PTTs was 13.8%. Patients who had ACC tended to have better survival rates than those with SCC, although the difference was not statistically significant (P=0.104). Compared with tumors located in upper third of the trachea, tumors located in the lower portion showed worse survival (P=0.0003). Patients who underwent complete surgical resection had significantly better survival compared to non-surgical therapies (P=0.016). The combination of chemoradiotherapy and bronchoscopic intervention was better than chemoradiotherapy alone (P=0.028). CONCLUSIONS: Histologic type, tumor location and treatment approaches likely influence clinical outcomes. Within the cohort described here, complete surgical resection was the optimal therapy for PTTs. For unresectable malignant PTTS, chemoradiotherapy with bronchoscopic intervention was a superior modality. Given the poor 5-year survival of PTT, larger-scale, multi-center studies are warranted to validate our findings and identify optimal therapeutic interventions.