Glomerular Lesions Research Articles

Revealing VCAN as a Potential Common Diagnostic Biomarker of Renal Tubules and Glomerulus in Diabetic Kidney Disease Based on Machine Learning, Single-Cell Transcriptome Analysis and Mendelian Randomization.

Diabetic kidney disease (DKD) is recognized as a significant complication of diabetes mellitus and categorized into glomerular DKDs and tubular DKDs, each governed by distinct pathological mechanisms and biomarkers. Through the identification of common features observed in glomerular and tubular lesions in DKD, numerous differentially expressed gene were identified by the machine learning, single-cell transcriptome and mendelian randomization. The diagnostic markers versican (VCAN) was identified, offering supplementary options for clinical diagnosis. VCAN significantly highly expressed in glomerular parietal epithelial cell and proximal convoluted tubular cell. It was mainly involved in the up-regulation of immune genes and infiltration of immune cells like mast cell. Mendelian randomization analysis confirmed that serum VCAN protein levels were a risky factor for DKD, while there was no reverse association. It exhibited the good diagnostic potential for estimated glomerular filtration rate and proteinuria in DKD. VCAN showed the prospects into DKD pathology and clinical indicator.

Unraveling the power of peptides from Cucumaria frondosa coelomic fluid as multitarget therapy of diabetic kidney disease: An in-silico study

Diabetic kidney disease is a condition characterized by persistent albuminuria, diabetic glomerular lesions, and a reduced glomerular filtration rate in people with diabetes. Peptides in Cucumaria frondosa coelomic fluid have been proven to provide antidiabetic and anti-inflammatory activity that can be used as one of the innovations in developing a multitarget therapy, especially in diabetic kidney disease. Therefore, the aim of this study was to unravel the power of peptide-based metabolites from C. frondosa coelomic fluid as multitarget therapy for diabetic kidney disease using an in-silico study. UCSF Chimera software was utilized to construct the three-dimensional structure of coelomic fluid peptides from C. frondosa. The toxicity and allergenicity of peptides were examined using the ToxinPred and AllerTop websites, respectively. From the PDBJ database, the 3D structures of protein kinase B, alpha isoform (AKT1); vascular endothelial growth factor receptor 2 (VEGFR2); epidermal growth factor receptor (EGFR); α-glucosidase; and glucokinase were obtained. Molecular docking was carried out using MOE Software. In this in-silico study, peptide 9 (-10.32 kcal/mol), peptide 1 (-9.41 kcal/mol), and peptide 3 (-9.55 kcal/mol) were shown to act as specific adenosine triphosphate-competitive inhibitors of EGFR, AKT1, and VEGFR2, respectively. Peptide 8 (-11.06 kcal/mol) can specifically inhibit α-glucosidase by binding to its active site. Peptide 1 (-9.80 kcal/mol) is predicted to specifically inhibit glucokinase activity by blocking its active side. Molecular dynamics simulations confirmed stable interactions with receptor proteins. In conclusion, C. frondosa coelomic fluid peptides have been shown not only to alleviate diabetic kidney disease but also to stabilize blood glucose levels and prevent hyperglycemia based on in-silico analysis.

Unveiling pathology-related predictive uncertainty of glomerular lesion recognition using prototype learning.

Recognizing glomerular lesions is essential in diagnosing chronic kidney disease. However, deep learning faces challenges due to the lesion heterogeneity, superposition, progression, and tissue incompleteness, leading to uncertainty in model predictions. Therefore, it is crucial to analyze pathology-related predictive uncertainty in glomerular lesion recognition and unveil its relationship with pathological properties and its impact on model performance. This paper presents a novel framework for pathology-related predictive uncertainty analysis towards glomerular lesion recognition, including prototype learning based predictive uncertainty estimation, pathology-characterized correlation analysis and weight-redistributed prediction rectification. The prototype learning based predictive uncertainty estimation includes deep prototyping, affinity embedding, and multi-dimensional uncertainty fusion. The pathology-characterized correlation analysis is the first to use expert-based and learning- based approach to construct the pathology-related characterization of lesions and tissues. The weight-redistributed prediction rectification module performs reweighting- based lesion recognition. To validate the performance, extensive experiments were conducted. Based on the Spearman and Pearson correlation analysis, the proposed framework enables more efficient correlation analysis, and strong correlation with pathology-related characterization can be achieved (c index>0.6 and p<0.01). Furthermore, the prediction rectification module demonstrated improved lesion recognition performance across most metrics, with enhancements of up to 6.36%. The proposed predictive uncertainty analysis in glomerular lesion recognition offers a valuable approach for assessing computational pathology's predictive uncertainty from a pathology-related perspective. The paper provides a solution for pathology-related predictive uncertainty estimation in algorithm development and clinical practice.

Fbxo11 maintains mitochondrial function and prevents podocyte injury in adriamycin-induced nephropathy by mediating the ubiquitin degradation of Fosl2

Mitochondrial dysfunction is a pivotal factor in the onset of podocyte damage, which is a central component in the pathogenesis of nephrotic syndrome (NS). However, the precise mechanisms underlying the changes in podocyte mitochondria remain elusive. Our study aims to clarify the potential mechanisms involved in the role of F-box protein 11 (Fbxo11) in NS, specifically concentrating on its impact on mitochondrial function. A mouse model was established by tail vein injection of adriamycin (ADR, 10 mg/kg) and was infected with lentivirus overexpressing Fbxo11. Mouse podocytes (MPC-5) were infected with lenti-Fbxo11-OE, followed by treatment with 0.4 μg/mL of ADR. We identified the decreased expression of Fbxo11 in mouse kidney tissues and MPC-5 cells induced by ADR. Lenti-Fbxo11-OE intervention relieved ADR-induced glomerular lesion, podocyte injury, and mitochondrial dysfunction. In vitro, overexpression of Fbxo11 in mouse podocytes improved mitochondrial function and reduced podocyte damage, thereby inhibiting podocyte apoptosis. Mechanistically, Fbxo11 decreased the protein expression of Fosl2 through ubiquitin-dependent proteasomal degradation. Rescue experiments revealed that overexpression of Fosl2 abolished the protective effects of Fbxo11 overexpression on mitochondrial damage and podocyte injury. Importantly, the regulatory effects of the Fbxo11/Fosl2 axis were reversed when treated with the mitochondrial fission inhibitor mdivi-1. Taken together, our results demonstrated that Fbxo11-mediated ubiquitin degradation of Fosl2 is critical for maintaining mitochondrial function and preventing podocyte injury during NS.

Isolated microhematuria in potential kidney donors: evaluating kidney biopsy findings with dipstick urinalysis and urine microscopy results.

Isolated microhematuria (IMH) can signal hidden glomerular disease, necessitating detailed evaluations for potential kidney donors, including kidney biopsies. The optimal strategy for deciding on kidney biopsies remains unclear. While the British Transplant Society supports dipstick analysis, KDIGO focuses solely on urine microscopy. This study explored the correlation between kidney biopsy outcomes and results from dipstick urinalysis and urine microscopy in potential kidney donors. This retrospective study encompassed all potential kidney donors who received kidney biopsies following a positive urine dipstick result for IMH, irrespective of whether red blood cells (RBCs) were found on urine microscopy. We performed sensitivity and specificity analyses to assess the effectiveness of microscopy and dipstick urinalysis in identifying histological abnormalities in the kidney biopsies. Approximately 49% of potential donors-133 out of 271-who had kidney biopsies due to positive dipstick tests showed negative results in urine microscopy for RBCs. In total, 168 donor candidates, or 62%, had abnormal findings in their biopsies, with nearly half of those diagnosed with immunoglobulin A nephropathy having negative urine microscopy results. Furthermore, 58% of potential donors with negative urine microscopy results-77 out of 133-also exhibited abnormal biopsy findings. The urine microscopy test displayed a sensitivity of 54.2% (95% confidence interval 46.6-61.5) and a specificity of 54.4% (95% confidence interval 44.8-63.7) for detecting abnormal biopsy results. This study highlighted a significant presence of donors with IMH with underlying glomerular lesions. Using urine microscopy showed limited sensitivity and specificity in identifying abnormal histopathological results. Relying solely on urine microscopy may miss critical pathologies like IgAN in prospective kidney donors. The persistence of IMH during dipstick urinalysis calls for kidney biopsy in potential donors. These findings suggest that our results be incorporated into future global guideline formulations.

Minimal Change Disease and Focal Segmental Glomerulosclerosis Are Associated with Good Kidney Prognosis and Thrombotic Microangiopathy with Poor Kidney Survival in Patients with COVID-19-Associated Nephropathies

Introduction: The kidney is a frequent target of SARS-CoV-2, potentially developing lesions in glomeruli, vessels, and tubulointerstitium in response to this infection. Herein, we present the analysis of the first large Latin American cohort of adult patients undergoing kidney biopsy due to COVID-19-associated kidney disorders. Methods: This retrospective, multicenter, national study was based on the collection of information on demographics, comorbidities, laboratory data, kidney histology, therapy, and therapeutic response. Patients diagnosed with collapsing glomerulopathy (CG) were genotyped for APOL1. Results: Our cohort included 94 patients, most male (62.8%). The median age was 44 (33–52) years, and 50% of them were previously hypertensive. The time between COVID-19 diagnosis and kidney biopsy was 30 (15–60) days. Most patients had decreased kidney function at diagnosis, 43.5% required dialysis upon diagnosis, 77.6% received immunosuppression, and 2/3 achieved a clinical remission. CG was the most common kidney involvement (18 cases), reproducing previous findings. Focal segmental glomerulosclerosis (FSGS), thrombotic microangiopathy (TMA), and IgA nephropathy were also frequent, with 10 cases each. FSGS and minimal change disease (MCD) were associated with the best cumulative kidney survival; none started dialysis. In contrast, patients with TMA/C3 glomerulopathy presented a poor kidney prognosis, with more than half progressing to kidney replacement therapy. Conclusion: A novel and striking finding of our study, therefore, was the association of FSGS and MCD with the best kidney outcome among all COVID-19-related histological patterns. Moreover, the overall distribution of histological profiles showed significant particularities in the analyzed patient cohort, the most important being the higher frequency of TMA cases.

Fenofibrate attenuates renal lipotoxicity in uninephrectomized mice with high-fat diet-induced obesity.

The objective of this study was to investigate the role of fenofibrate, a peroxisome proliferator-activated receptor-α agonist, in obesity-induced kidney damage (lipotoxicity) in mice with uninephrectomy. C57BL/6 mice underwent uninephrectomy and sham surgeries and were fed normocaloric or high-fat diets. After 10 weeks, obese mice were administered 0.02% fenofibrate for 10 weeks. Kidney function and morphology were evaluated, as well as levels of inflammatory and fibrotic mediators and lipid metabolism markers. High-fat diet-fed mice developed characteristic obesity and hyperlipidemia, with subsequent renal lipid accumulation and damage, including mesangial expansion, interstitial fibrosis, inflammation, and proteinuria. These changes were greater in obese uninephrectomy mice than in obese sham mice. Fenofibrate treatment prevented hyperlipidemia and glomerular lesions, lowered lipid accumulation, ameliorated renal dysfunction, and attenuated inflammation and renal fibrosis. Furthermore, fenofibrate treatment downregulated renal tissue expression of plasminogen activator inhibitor-1, monocyte chemoattractant protein-1, and local expression of fibroblast growth factor-21. Peroxisome proliferator-activated receptor-α activation by fenofibrate, with subsequent lipolysis, attenuated glomerular and tubulointerstitial lesions induced by renal lipotoxicity, thus protecting the kidneys of uninephrectomy mice from obesity-induced lesions. The study findings suggest a pathway in the pharmacological action of fenofibrate, providing insight into the mechanisms involved in kidney damage caused by obesity in kidney donors.

Combined nutcracker syndrome and glomerulonephritis in pediatric patients: a single-center retrospective case series.

Nutcracker syndrome (NCS) has been reported to coexist with various glomerulonephritis (GN). This study investigated clinical features of NCS combined with GN in a pediatric case series and the possible relationship between these two conditions. Clinical and pathologic findings of 15 children with NCS and biopsy-proven GN were analyzed. NCS was diagnosed with renal Doppler ultrasonography, abdominal computed tomography, and/or magnetic resonance imaging. Glomerular lesions were divided into two pathological categories: minor glomerular abnormalities (MGAs) and definite GN. Mean age of all patients was 11 ± 3.36 years and mean follow-up duration was 53.8 ± 29.3 months. Chief complaint was proteinuria with or without hematuria. During follow-up, five patients developed left kidney enlargement. Abnormal levels in immunological tests were revealed in 10 patients. Extrarenal symptoms including gonadal varicocele, splenic cyst, syncope, and anemia were found in seven patients. On kidney biopsy, seven patients had MGAs and eight children showed definite GN (one case of focal GN, one case of mesangial proliferative GN, one case of focal segmental glomerulosclerosis, two cases of immunoglobulin A [IgA] vasculitis nephritis, and three cases of IgA nephropathy). While the MGA group showed a higher proportion of isolated proteinuria and a lower estimated glomerular filtration rate (eGFR) at the last visit, there were no differences in age, clinical features of NCS, extrarenal symptoms, immunological tests, and eGFR decline rate between the two groups. NCS may be associated with the presence of various GN. The causal relationship between NCS and GN should be further investigated.

Higher density of CD4+ T cell infiltration predicts severe renal lesions and renal function decline in patients with diabetic nephropathy.

More evidence have shown that the combination of immune and inflammatory mechanism was critical in diabetic nephropathy (DN). However, the relationship between CD4+ T cells and the development of DN is still unclear. Therefore, this study will focus on this issue from the perspective of clinicopathology. From September 2019 to December 2022, a total of 112 adult patients with DN were enrolled in the study. According to the density of CD4+ T cell infiltration based on immunostaining, the patients were divided into high-CD4 group (56 patients) and low-CD4 group (56 patients). Another 25 diabetic patients with minimal change disease (non-diabetic nephropathy, NDN) was reviewed as control group in clinical and molecular analysis. The clinical parameters, morphological features, and molecular characteristics were compared. The predictive value of CD4+ T cells for DN prognosis was also investigated. DN patients in the high-CD4 group suffered from higher proteinuria and lower estimated glomerular filtration rate (eGFR) level than those in the low-CD4 group and NDN patients. Renal biopsy in the high-CD4 group presented with more severe glomerular lesions, higher density of interstitial inflammation, and more severe tubular atrophy/interstitial fibrosis than in the low-CD4 group. Multivariate logistic analysis indicated that the density of CD4+ T cell infiltration could independently predict the severity of tubular atrophy/interstitial fibrosis. In addition, more severe mitochondrial damage of renal tubular epithelial cells and a more obvious expression of Bcl6, IL-6, STAT3, and TGFβ1 were observed in DN patients of the high-CD4 group, indicating the possible mechanism of CD4+ T cells involving the progression of DN. Multivariate Cox regression analysis revealed that a higher intensity of interstitial CD4+ T cell deposition remained as an independent predictor of the double endpoint with doubling of baseline serum creatinine or end-stage renal disease. The high density of CD4+ T cell infiltration was associated with renal function decline and severity of renal lesions and predicted poor renal survival for DN patients.

Clinical characteristics of monoclonal immunoglobulin-associated renal disease: a retrospective cohort study.

Clinical epidemiological data on monoclonal gammopathy of renal significance (MGRS) are lacking. In this retrospective observational study, MGRS was compared with B-cell or plasma cell malignancies (BCM/PCM) with renal involvement to clarify differences in their clinical features. Among the 1408 renal biopsies performed at our hospital, 25 MGRS and 18 BCM/PCM patients were identified. We investigated baseline characteristics and hematologic parameters of MGRS in reference to BCM/PCM using multivariable analysis. Cox proportional hazards analysis was performed for end-stage kidney disease (ESKD) and all-cause mortality. Comparing the MGRS with the BCM/PCM, meandifferences in creatinine level, estimated glomerular filtration rate, and clonal bone marrow plasma cell percentage were -2.76mg/dL, 27.72mL/min/1.73m2, and -18.86%, respectively (all P < 0.001). MGRS group had a predominance of glomerular lesions such as immunoglobulin-associated amyloidosis, cryoglobulinemic GN, and MIDD, and a lower risk of acute kidney injury/acute renal disease compared to BCM/PCM. During a median observation period of 23.7months, clone-directed therapy was performed in 32.0% of patients in the MGRS group, compared to 83.3% of patients in the BCM/PCM group. Compared with BCM/PCM, MGRS had a hazard ratio of 0.66 (95% confidence interval (CI) 0.23-1.92, P = 0.45) for ESKD and 0.33 (95% CI 0.11-1.03, P = 0.06) for death in multivariate logistic regression analysis. The clinical characteristics of MGRS and BCM/PCM with monoclonal immunoglobulin-associated renal disease are disparate. Understanding these differences is crucial for developing tailored clinical approaches and therapeutic strategies to improve patient outcome.

Urinary Biomarkers Associated With Pathogenic Pathways Reflecting Histologic Findings in Lupus Nephritis.

There is a pressing need to understand the pathogenesis of histologic findings and identify the biomarkers for predicting the histologic severity in lupus nephritis (LN). This study aimed to identify the pathogenic signal pathway and elucidate urinary biomarkers for predicting the presence or severity of histologic findings in LN. Urine samples from patients with biopsy-proven active LN were screened for 1,305 proteins using an aptamer-based proteomic assay. The diversity and expansion of individual renal histologic features in LN were quantified to identify the urinary proteins associated with the histologic findings found in each score. Candidate urinary proteins were validated in a validation cohort. Immunohistochemical staining of the renal tissues was performed to clarify the localization of the candidate proteins. Cluster analysis extracted five histologic subgroups according to their correlations with each histologic finding in LN. Protein groups that correlated with each histologic subgroup revealed a distinct pathogenesis in LN using pathway analyses. Enzyme-linked immunosorbent assay validation revealed that urinary calgranulin B (S100A9), monocyte chemotactic protein 1 (MCP-1), and insulin-like growth factor binding protein 5 (IGFBP-5) levels could specifically predict the presence and severity of active glomerular lesions, interstitial inflammation, and interstitial fibrosis, respectively. Immunohistochemical staining revealed the localization of these proteins in each lesion. Renal histologic findings may reflect the different pathogeneses involved in each lesion, and estimating the urinary calgranulin B, MCP-1, and IGFBP-5 levels may be useful in predicting the presence and severity of histologic findings in LN.

Outgrowth of Escherichia is susceptible to aggravation of systemic lupus erythematosus

BackgroundSystemic lupus erythematosus (SLE) is linked to host gut dysbiosis. Here we performed faecal gut microbiome sequencing to investigate SLE-pathogenic gut microbes and their potential mechanisms.MethodsThere were 134 healthy controls (HCs) and 114 SLE cases for 16 S ribosomal RNA (rRNA) sequencing and 97 HCs and 124 SLE cases for shotgun metagenomics. Faecal microbial changes and associations with clinical phenotypes were evaluated, and SLE-associated microbial genera were identified in amplicon analysis. Next, metagenomic sequencing was applied for accurate identification of microbial species and discovery of their metabolic pathways and immunogenic peptides both relevant to SLE. Finally, contribution of specific taxa to disease development was confirmed by oral gavage into lupus-prone MRL/lpr mice.ResultsSLE patients had gut microbiota richness reduction and composition alteration, particularly lupus nephritis and active patients. Proteobacteria/Bacteroidetes (P/B) ratio was remarkably up-regulated, and Escherichia was identified as the dominantly expanded genus in SLE, followed by metagenomics accurately located Escherichia coli and Escherichia unclassified species. Significant associations primarily appeared among Escherichia coli, metabolic pathways of purine nucleotide salvage or peptidoglycan maturation and SLE disease activity index (SLEDAI), and between multiple epitopes from Escherichia coli and disease activity or renal involvement phenotype. Finally, gavage with faecal Escherichia revealed that it upregulated lupus-associated serum traits and aggravated glomerular lesions in MRL/lpr mice.ConclusionWe characterize a novel SLE exacerbating Escherichia outgrowth and suggest its contribution to SLE procession may be partially associated with metabolite changes and cross-reactivity of gut microbiota-associated epitopes and host autoantigens. The findings could provide a deeper insight into gut Escherichia in the procession of SLE.

Renal involvement in TAFRO syndrome: a review.

Renal involvement in TAFRO syndrome is characterized clinically by general edema with ascites and pleural effusions and a rapidly progressive decline in renal function, with urinary protein levels of usually less than 1g/day. The histologic features of the kidneys can be described as glomerular microangiopathy characterized by mesangiolysis or mesangial loosening, endothelial cell proliferation, edematous opening in the subendothelial space, and glomerular basement membrane (GBM) doubling due to newly formed basement membrane. Findings such as rupture of the GBM, foot-process effacement or fusion, and epithelial cell loss are rare, and thrombus formation is difficult to identify in the glomerulus. Furthermore, immunodeposits are not seen on immunofluorescence staining or electron microscopy. Unlike adults, in addition to the glomerular lesions described above, adolescents appear to show intimal proliferation of the arterioles and interlobular arteries to the vascular poles and occlusion of the vascular lumen.

Novel TBC1D8B variant causes neonatal nephrotic syndrome combined with acute kidney injury

BackgroundNephrotic syndrome (NPHS), characterized by proteinuria, hypoalbuminemia, and edema, can be caused by genetic variations. TBC1D8B was recently discovered as a novel disease-causing gene for X-linked NPHS. With only a few reported cases, the clinical manifestations associated with variants of this gene need to be further examined.MethodsWe recruited a newborn with NPHS complicated by acute kidney injury (AKI) and his parents and tested the potential genetic cause of the disease through trio-whole exome sequencing and Sanger sequencing. Western blotting (WB) was performed using a mutant plasmid to evaluate mutant protein expression levels. Since the TBC1D8B protein interacts with RAB proteins to catalyze the GTPase hydrolysis process, immunofluorescence (IF) can be used to verify the interaction between the TBC1D8B mutant protein and RAB11A/RAB11B, and thus to confirm its effect on the endocytosis and vesicle recycling functions of RAB proteins within the cell.ResultsThe child, at 1 month, showed severe edema and proteinuria and unexplained coma with epilepsy. Ultrasound examination revealed multiple organ enlargement, and MRI showed nonspecific high diffusion-weighted imaging signal characteristics in the splenium of the corpus callosum. Hematoxylin and eosin staining showed diffuse inflammatory cell infiltration in the renal interstitium and multifocal renal tubule lumen expansion. Diffuse fusion of podocyte foot processes was observed under electron microscopy, indicating glomerular podocyte lesions. Genetic testing revealed a maternally inherited novel hemizygous variant, NM_017752: c.628 A > T, p.Lys210Ter, in TBC1D8B. In vitro functional experiments showed that this variant may lead to TBC1D8B protein degradation. IF results showed disrupted interaction with RAB11A/RAB11B, that then affects the biological function of RAB proteins in the process of cell intimal vesicle formation and intracellular transport.ConclusionThis study will enrich the mutational and phenotypic spectra of TBC1D8B and demonstrate the potential of this gene variants to cause early-onset NPHS leading to severe kidney disease.

Dynamics of CD4+ and CD8+ Lymphocytic Inflammatory Infiltrates in Lupus Nephritis.

Lupus nephritis (LN) is a common clinical manifestation of systemic lupus erythematosus (SLE). Our study aims to quantitatively analyze CD4+ and CD8+ lymphocytes in different areas and LN classes and describe a specific distribution pattern that is correlated with the severity of LN-specific lesions. In total, 53 LN renal biopsies were immunohistochemically investigated using anti-CD4 and anti-CD8 antibodies. T lymphocytes were counted in 3 areas, including intraglomerular, periglomerular, and interstitial regions. The severity of glomerular and tubulo-interstitial lesions was assessed using an original semi-quantitative algorithm based on the renal corpuscle score (RC_S) and the tubulo-interstitial score (TI_S). The number of CD8+ T lymphocytes was higher than that of CD4+ T lymphocytes in each of the three areas and in each LN class, showing statistically significant differences. ANOVA analysis of all LN classes showed significant differences between periglomerular and interstitial CD4+ and CD8+ T lymphocytes, respectively. Irrespective of location, the number of CD8+ T lymphocytes statistically correlates with the RC_S and the TI_S; no significant correlations were found between the number of CD4+ T lymphocytes and the RC_S and the TI_S for all three considered areas. Our data provide strong evidence supporting the major role of CD8+ lymphocytes in LN lesion progression, with CD4+ lymphocytes playing a limited role.

A Novel Deep Learning Approach for Analyzing Glomerular Basement Membrane Lesions in a Mouse Model of X-Linked Alport Syndrome

Alport syndrome is a rare kidney disease typically more severe in males due to its X-linked inheritance. However, female patients with heterozygous X-linked Alport syndrome (XLAS) can develop renal failure over time, necessitating accurate pathological assessment for effective therapy. A key pathological finding in female XLAS patients is the mosaic pattern of partial loss of α5 chains of type IV collagen. This study, using a mouse model of XLAS with a nonsense mutation (R471*) in the Col4a5 gene, analogous to human XLAS, aimed to examine the consistency of this pattern with the glomerular basement membrane (GBM) structure. A modified periodic acid-methenamine silver (PAMS) staining method was developed for clearer GBM visualization. The integrated images from COL4α5-stained fluorescence, PAMS, and low-vacuum scanning electron microscopy (LVSEM) into a single-slide section and applied supervised deep learning to predict GBM lesions. Results showed significant individual variability in urinary protein levels and histological lesions. Pathological parameters, including crescent formation, focal segmental glomerulosclerosis, and the COL4α5/α2 ratio, correlated with clinical parameters like urinary protein and plasma creatinine levels. Integrated LVSEM analysis revealed dense GBM regions corresponded to areas where COL4α5 was preserved, while coarse GBM (basket-weave lesions) occurred in COL4α5-deficient regions. These advanced techniques can enhance biopsy-based diagnosis of Alport syndrome and aid in developing AI diagnostic tools for diseases involving basement membrane lesions.

Porphyromonas gingivalis Induces Chronic Kidney Disease through Crosstalk between the NF-κB/NLRP3 Pathway and Ferroptosis in GMCs.

Porphyromonas gingivalis (P.gingivalis) is a gram-negative bacterium found in the human oral cavity and is a recognized pathogenic bacterium associated with chronic periodontitis and systemic diseases, including chronic kidney disease (CKD), but the roles and molecular mechanism of P.gingivalis in CKD pathogenesis are unclear. In this study, an animal model of oral P.gingivalis administration and glomerular mesangial cells (GMCs) cocultured with M1-polarized macrophages and P.gingivalis supernatant were constructed. After seven weeks of P.gingivalis gavaged, peripheral blood was collected to detect the changes in renal function. By collecting the teeth and kidneys of mice, H&E staining and IHC were used to analyze the expression of periodontal inflammatory factors in mice, PAS staining was used to analyze glomerular lesions. The supernatant of macrophages was treated with 5% P.gingivalis supernatant. H&E staining, IHC, Western blot and RT-PCR were applied to analyze renal inflammatory factors, macrophage M1 polarization, NF-κB, NLRP3 and ferroptosis changes in vitro. We found that oral P.gingivalis administration induced CKD in mice. P.gingivalis supernatant induced macrophage polarization and inflammatory factor upregulation, which triggered the activation of the NF-κB/NLRP3 pathway and ferroptosis in GMCs. By inhibiting the NF-κB/NLRP3 pathway and ferroptosis in GMCs, cell viability and the inflammatory response were partially alleviated in vitro. We demonstrated that P.gingivalis induced CKD in mice by triggering crosstalk between the NF κB/NLRP3 pathway and ferroptosis in GMCs. Overall, our study suggested that periodontitis can promote the pathogenesis of CKD in mice, which provides evidence of the importance of periodontitis therapy in the prevention and treatment of CKD. P.gingivalis promotes ferroptosis in kidneys and accelerates the progression of CKD through NF-κB/NLRP3 signaling pathway.

Association of pulse pressure with incident end-stage kidney disease according to histopathological kidney findings in patients with diabetic nephropathy.

Diabetic patients as well as the elderly are known to have high pulse pressure (PP), but there are few studies on how microangiopathy and macroangiopathy are involved in its mechanism. In this study, we examined the association between PP and atherosclerotic lesions by vessel size in kidney biopsy tissue and examined how PP is associated with kidney prognosis. This retrospective observational study included 408 patients with biopsy-proven diabetic nephropathy at Nara Medical University Hospital. Exposure of interest was PP measured at kidney biopsy. Outcome variable was kidney failure with replacement therapy (KFRT). Cox proportional hazards and competing risk regression models with all-cause mortality as a competing event were used to examine these associations. A total of 408 patients were divided into tertiles based on PP (mmHg): Tertile 1 (reference), <51; Tertile 2, 51-64; and Tertile 3, >64. Among the 408 patients, 99 developed KFRT during a median follow-up period of 6.7 years. Higher PP was independently associated with higher incidences of KFRT (hazard ratio [95% confidence interval] for Tertile 3 vs. Tertile 1; 2.07 [1.05-4.09]. In histological lesions, PP was strongly associated with glomerular lesions, tubulointerstitial lesions, and arteriolar hyalinosis (all ps for trend <0.001), but not with intimal thickening (p for trend = 0.714). PP was significantly associated with diabetic glomerular/tubulointerstitial lesions and arteriolar hyalinosis but not with intimal thickening at the time of kidney biopsy and was also significantly associated with subsequent KFRT in patients with diabetic nephropathy.

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-β1/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.

Periodic Acid Schiff Staining to Detect Mott Cells, Aberrant Plasma Cells Containing Immunoglobulin Inclusions Called Russell Bodies.

Hematoxylin and eosin staining is widely used for routine histopathological analysis under light microscopic examination to determine alterations of tissue architecture and cellular components in animal studies. Aside from hematoxylin/eosin staining, periodic acid Schiff (PAS) staining is used to detect polysaccharides and carbohydrate-rich macromolecules, and is essential in immunological fields for evaluation of glomerular lesions of kidneys in autoimmune animals. Since erythrocytes are not stained by PAS, this stain is also helpful for identifying changes in immune cells in the red pulp of the spleen, which is filled with erythrocytes. This article describes a protocol to detect Mott cells, bizarre plasma cells containing immunoglobulin inclusion bodies (Russell bodies) in the cytoplasm. The protocol can be used for formalin-fixed, paraffin-embedded tissue sections, frozen tissue sections, tissue-touch preparations, blood films, and cytocentrifuged cell smears. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Detection of Mott cells by PAS staining in formalin-fixed, paraffin-embedded tissue sections Basic Protocol 2: Detection of Mott cells by PAS staining in frozen tissue sections, touch preparations, blood films, and cytocentrifuged cell smears.