bluuebunny/crossref_metadata_2025 huggingface dataset:
#1333 SGLT2 inhibitors as a treatment for Fanconi-Bickel syndrome: a case report
Authors: D'ambrosio Viola , Wan Elizabeth , Siew Keith , Ferraro Pietro Manuel , Walsh Stephen
Published: May 2024

Background and Aims

Fanconi-Bickel syndrome is an ultra-rare genetic disease characterized by SLC2A2 mutation encoding for the basolateral glucose transporter (GLUT2) in the proximal tubule of the nephron. This defective transport ultimately leads to accumulation of glycogen and dysfunction of proximal tubule cells. This manifests clinically as the renal Fanconi syndrome and eventually kidney failure. Systemic complications of proximal tubule injury include metabolic acidosis, bone demineralization and, for some not completely elucidated reasons, dysglycemia.

Method

We present the case of a 43-year-old man who was diagnosed with Fanconi-Bickel syndrome (homozygous splice site mutation in SLC2A2). He had a history of infantile-onset renal Fanconi syndrome, hypercalciuria and bilateral nephrolithiasis, osteoporosis, bilateral sensorineural deafness and non-insulin dependent type 2 diabetes. At referral the patient presented with CKD G2, non-anion gap metabolic acidosis, slightly elevated serum calcium, decreased serum phosphate, suppressed PTH and hypercalciuria (Table 1), despite oral supplementation of phosphate, bicarbonate and vitamin D. We hypothesized that SGLT2i in this patient may halt the progressive proximal tubule injury by preventive glucose uptake and help the management of diabetes.

Results

Fractional excretion of phosphate (FEPO4) and urinary retinol-binding protein (RBP)-creatinine ratio, two markers of proximal tubular injury, were stable after 2 months of SGLT2i therapy (Fig. 1).

Conclusion

To date, Fanconi-Bickel syndrome does not have a specific treatment. Standard of care includes supplements of fluids and electrolytes to counterbalance proximal tubular injury and management of complications such as diabetes. SGLT2i use has been described in a mouse model of another glycogen storage disease (GSD1b), whose underlying defect is different from that of Fanconi-Bickel but presents with a similar phenotype [2]. Data showed that gliflozins prevents glycogen accumulation and restores proximal tubule cells’ function. Using the same rationale, the administration of SGLT2i in adult patients with Fanconi-Bickel syndrome may prevent further proximal damage and slow the progression towards end-stage kidney disease. In conclusion, we hypothesize a potential benefit of SGLT2i in adult patients affected by Fanconi-Bickel syndrome.
#1012 Lifetime risk of autosomal recessive kidney diseases calculated from genetic databases
Authors: Braunisch Matthias , Großewinkelmann Clara , Menke Martin , Hannane Nora , Ćomić Jasmina , Guenthner Roman , Renders Lutz , Schmaderer Christoph , Heemann Uwe , Riedhammer Korbinian , Wagner Matias , Höfele Julia
Published: May 2024

Background and Aims

Genetic kidney diseases represent an often rare and clinically diverse group. Their distinct clinical and genetic variations and biases in patient referrals and identification pose challenges in phenotype-based estimated prevalences. This study aimed to determine the calculated lifetime risk of autosomal recessive kidney diseases.

Method

We conducted a thorough literature review to compile a list of 149 genes linked to these diseases. Disease-causing variants were collected from ClinVar, HGMD, LOVD, and our database and reevaluated according to current guidelines. Minor allele frequencies were obtained from gnomAD and our database. We estimated the lifetime risk of autosomal recessive kidney diseases in a dataset of 12,800 disease-causing variants across 149 disease-associated genes (31 glomerulopathy, 16 tubulopathy, 87 ciliopathy, and 15 CAKUT genes).

Results

The combined estimated lifetime risk is 10.68 per 100,000 (95% confidence interval 6.29-18.40) based on our data and 22.77 per 100,000 (15.86-33.77) using the European gnomAD dataset. Notably, the three disorders with the highest lifetime risk (≥1.2 per 100,000), collectively accounting for 28% of the overall lifetime risk, were caused by PKHD1 (autosomal recessive polycystic kidney disease), SLC12A3 (Gitelman syndrome), and COL4A3 (Alport syndrome) variants (Fig. 1). Extrapolation to all modes of inheritance, the overall lifetime risk for monogenic kidney disease in adults ranged from 1 in 602 to 1 in 1,283 (Fig. 2).

Conclusion

This study provides a population-genetic estimate of lifetime risk for autosomal recessive kidney diseases across different populations, addressing underestimated prevalences and diagnostic probabilities. The data, therefore, informs resource allocation for therapy development, public health management, and biomedical research.
#1964 Diagnosis performance of urine oxalate/creatinine ratio for hyperoxaluria screening
Authors: Letourneau Pierre , Cabezas Lara , De Mul Aurelie , Machon Christelle , Poussineau Cécile , Aquavivia Cécile , Bacchetta Justine , Derain-Dubourg Laurence , Lemoine Sandrine
Published: May 2024

Background and Aims

Primary and secondary hyperoxaluria is characterized by significantly elevated urinary oxalate levels, increased risk of kidney stones, nephrocalcinosis, and chronic kidney disease. Patients with enteric hyperoxaluria are especially at high-risk populations. However, identifying hyperoxaluric individuals within these populations remains challenging due to difficulties in obtaining complete urine collections. This study aims to evaluate the diagnostic performance of the urine oxalate/creatinine ratio to improve the screening of hyperoxaluria.

Method

We pooled data from an adult tertiary renal exploration center, including living donors, short bowel syndrome patients, bariatric surgery patients, and individuals with nephrolithiasis or other nephrological issues undergoing 24-hour urine analysis. We assessed the relationship between the urine oxalate/creatinine ratio and 24-hour oxalate excretion. The diagnostic performance of the ratio was analyzed using ROC curves, and an optimal diagnostic threshold was established.

Results

Of the 1485 initially included adult patients reported in Table 1, 37% lacked complete urine collections, resulting in a study population of 974 individuals (453 females, 521 males, median age 48 years, median renal function 97 ml/min/1.73 m²). Nineteen percent had hyperoxaluria, with a higher prevalence in females (25% vs. 13% in males). Median 24-hour oxaluria was 548 (432,740) µmol/d in the diseased group and 244 (188,309) µmol/d in the healthy group. A strong correlation (Spearman's rank correlation rho= 0.8, p < 0.001) was found between the urine oxalate/creatinine ratio and 24-hour oxalate excretion. ROC curves for both genders exhibited similar performance, with an optimal threshold for the entire population yielding an AUC of 0.97 (0.962-0.981). The diagnostic threshold for maximum sensitivity was an oxalate/creatinine ratio of 0.025 mmol/mmol (Sensitivity = 1, Specificity = 0.65, PPV = 0.4, NPV = 1), while for maximum specificity, it was an oxalate/creatinine 0.074 mmol/mmol (Sensitivity= 0.31, Specificity = 1, PPV = 1, NPV = 0.862). The optimal diagnostic threshold chosen by the minimum distance from the left-upper corner was an oxalate/creatinine 0.034 mmol/mmol (Sensitivity= 0.92, Specificity = 0.91, PPV = 0.69, NPV = 0.98) (Fig. 1).

Conclusion

The urine oxalate/creatinine ratio demonstrates excellent diagnostic performance and is efficient in screening hyperoxaluric patients within high-risk populations. However, the positive predictive value is insufficient to be a standalone reliable diagnostic test. Therefore, 24-hour urine oxalate measurement remains necessary for diagnosis.
#851 Effects of gliflozins on endothelial cells: in vitro and clinical evidence
Authors: Borriello Gianmarco , Joshi Rashmi , Ortiz Alberto , Fernandez-Prado Raul , Ingrosso Diego , Perna Alessandra , Genualdo Raffaele , Settembrini Silvio , Mone Pasquale , Borriello Margherita , Viggiano Davide
Published: May 2024

Background and Aims

Gliflozins are a class drugs widely used in diabetes as they act as sodium-glucose co-transporter type 2 inhibitors (SGLT2i). Irrespective from glycaemic control, SGLT2i are known to possess kidney and heart protective effects.

The kidney- and heart-protective effects of gliflozins (SGLT2i) have received different explanations because of their efficacy in non-diabetic patients. Indeed, the non-glycemic effects of SGLT2i are puzzling because SGLT2, the molecular target of gliflozins, is mainly expressed in proximal tubule cells, with very low expression levels in other cell types. Though SGLT2 inhibitors might be nephroprotective because of a reduction of eGFR, this mechanism seems insufficient to explain heart protection.

Emerging evidence suggests that SGLT2i have off-target effects in endothelial cells. In this study, we analyze this assumption by testing the effects of gliflozins on endothelial cells in vitro and verifying a differential effect of gliflozins on glomerular diseases involving primarily the endothelial compartment vs those involving podocytes or both.

Methods

In vitro studies have been conducted on EA.hy926 cells. A dose-response curve of gliflozins on mitochondrial activity and cell viability has been obtained using MTT staining. Morphological parameters were obtained using phase contrast microscopy, and the details of the plasma membranes were studied using Atomic Force microscopy.

Patients with IgA nephropathy, minimal change disease or Focal Segmental Glomerulo Sclerosis FSGS, and with diabetic nephropathy (n = 12 per group). were studied for the percent change in albuminuria and creatinine four months after gliflozin treatment (empagliflozin or dapagliflozin). Three additional control groups (IgA, podocytopathies, diabetes) without gliflozin treatment (n = 12 per group) were also included.

Results

Gliflozin treatment induced a dose-response improvement in EA.hy926 cells' survival and restoration of cell-cell borders in AFM images. In patients, the albuminuria was reduced by a similar extent (−38 ± 6%) in all groups when treated with gliflozins. However, in diabetic patients and podocytopathies, this was associated with decreased eGFR (−6% and −8%), whereas in IgA nephropathy, the eGFR levels were increased after treatment (+3.8%).

Conclusion

In vitro, gliflozins show a direct endothelial protection effect. In vivo, part of the effects on proteinuria may be explained by a hemodynamic effect on the glomerular filtration rate in diseases affecting podocytes (diabetes, MCD, FSGS), as shown by the increase in creatinine. However, for diseases involving the endothelium (IgA nephropathy), the endothelial protection effect of gliflozins is demonstrated by the reduction in proteinuria and the protective effect on creatinine levels.
#2263 Computational drug repurposing screen targeting PLA2R antibody binding
Authors: Lloyd Aled , Austin-Muttitt Karl , Mullins Jonathan
Published: May 2024

Background and Aims

Approximately 60% of patients with membranous nephropathy have antibodies against the phospholipase A2 receptor (PLA2R). The cysteine rich (CysR) epitope of PLA2R is a likely site of protein-antibody interaction. Current treatment regimens for membranous nephropathy involve maximal conservative management or systemic immunosuppression in severe cases. We have developed protocols and programs for an in silico high-throughput repurposing screen using structural modelling, docking, and molecular dynamics (MD). Uniquely, our approach uses a bespoke interface on Google Colab for graphic processing units to run the MD simulations. We describe their application to a repurposing screen aiming to identify larger licensed drug molecules capable of impeding antibody-protein interactions at the site of the CysR epitope.

Method

A complete model of PLA2R was obtained from I-TASSER using the canonical sequence on the UNIPROT database. This structure was equilibrated using a five nanosecond molecular dynamics (MD) simulation. The simulation was prepared using CHARMM-GUI and run on the GROMACS-ON-COLAB platform. The centroid of the MD system between three and five nanoseconds was used for docking experiments using PLANTS PLP with a study area that included the CysR epitope. A library of compounds listed in the British National Formulary was used for the docking studies. The results would be analysed by PLANTS energy and by key residue overlap score.

Results

Viable docking results were obtained for 891 of the 1510 compounds tested. 60 of these compounds were in contact with at least 10% of the residues in the CysR region. By restricting these results to compounds in the lowest 20% of the total sample for calculated binding energy, 22 compounds remained. 16 of these compounds have been assessed for their safety for oral or intravenous use. These sixteen compounds were then identified for further investigation by MD to assess the stability of the identified interactions. The sixteen compounds include Lymecycline, Trazodone, Mirabegron, Sulfasalazine, Methotrexate, Rosuvastatin and Montelukast.

Conclusion

Structural bioinformatics methods provide a relatively fast and economical option for identifying protein-drug interactions that could result in new treatment strategies. The compounds identified for investigation are used for an array of different health conditions. However, they all share the chemical properties of large molecular weight and have the potential to form multiple hydrogen bonds. If validated experimentally, these compounds could provide new treatment options for PLA2R antibody positive membranous nephropathy.
#2518 The decrease of the filtration slit density, not proteinuria, is the early indication of the filtration barrier dysfunction
Authors: Endlich Nicole , Chadjichristos Christos , Chatziantoniou Christos , Telli Nihal , Drenic Vedran , Endlich Tim
Published: May 2024

Background and Aims

Intact podocyte foot processes (FP) play a crucial role in ensuring proper selective filtration in the kidney. Changes in FP morphology are thought to be the initial trigger for proteinuria, but definitive proof is still missing. As FP structures are below the optical resolution of light microscopes, changes are investigated by electron microscopy (EM) on ultrathin sections. In this study, the correlation between morphology and proteinuria was investigated using the Podocyte Exact Morphology Measurement Procedure (PEMP), a 3D-SIM-based technique. Our investigation was focused on podocyte damage caused by treatment with nephrotoxic serum (NTS) as a model for focal segmental glomerulosclerosis.

Method

The mice were treated with nephrotoxic serum (NTS), and kidneys were taken at 24, 48, and 72 hours after injection. Kidney sections (3 µm thick) were prepared for 3D-SIM analysis after staining with podocin and integrin and then fixed in formalin and embedded in paraffin. Filtration slit density (FSD) was quantified using the Podocyte Exact Morphology Measurement Procedure (PEMP) as described earlier (Siegerist et al. 2017). In addition, EM was performed on glutaraldehyde-fixed tissue samples using standard protocols. The albumin to creatinine ratio was also determined.

Results

We observed that NTS-treated mice developed moderate proteinuria after 48 hours. Using the super-resolution microscopy-based 3D-SIM technique to quantify podocyte PF morphology by calculating the filtrations slit density (FSD) revealed a significant reduction of the FSD in NTS-treated mice already after 24 hours. This structural change was confirmed by transmission electron microscopy analysis, showing that the effacement of podocytes FPs is the first sign of a change in the filtration barrier function before proteinuria is measurable.

Conclusion

PEMP analysis of standard histological sections from NTS-injected and control mice demonstrated that the first event in the functional loss of the size selectivity of the filtration barrier is the effacement of FP morphology, followed by detectable proteinuria. Therefore, the assessment of the FSD is a promising strategy for early and accurate detection of the loss of filtration barrier integrity, providing opportunities for faster and more precise diagnostics.
#2922 The role of urinary extracellular-derived miRNAs dysregulation in IgA nephropathy
Authors: Ardalan Mohammadreza , Farzamikia Negin , Zununivahed Sepideh
Published: May 2024

Background and Aims

IgA nephropathy (IgAN) is one of the most common forms of glomerulonephritis and causes hematuria and proteinuria by damaging the mesangial and podocyte cells. Urinary extracellular vesicles (uEVs) derived from damaged podocytes may reflect podocyte damage in various glomerular diseases and are considered an early and noninvasive diagnostic method. This study aimed to extract urinary extracellular vesicles (EVs) and investigate the expression dysregulation and diagnostic value of miR-29c, miR-146a, miR-148b, miR-155, miR-200b, and miR-429 in urine samples from patients with IgAN.

Method

Urine samples were collected from 20 patients with IgAN, 30 patients with membranous nephropathy (MGN), and 16 healthy individuals to extract Urinary EVs by ultracentrifugation. The characterization of EVs was evaluated by the specific protein markers of the EVs, flotillin-1, ALiX, and CD-9, along with histone H1 and podocyte-specific marker podocalyxin via western blotting. SEM and DLS were used to investigate the size and morphology of EVs. The expression levels of the miRNAs were evaluated using Real-time PCR. 

Results

Numerous extracellular vesicles >100 nm in size were present in the urine sample which were considered as EVs based on references. There were higher levels of the specific markers flotillin-1, ALiX, and podococalyxin in the urine samples of IgAN patients than in the control samples (P < 0.001 and P < 0.001, respectively). There was a statistically significant difference among the expression level of miR-29c (P = 0.002 and P = 033) in the group of IgAN patients compared to MGN patients and the group of healthy people, based on Rock curve analysis this urinary marker could discriminate the IgAN patients from MGN group, the area under the curve AUC ≥ 0.73.

Conclusion

This study showed that the different levels of miRNAs studied in urinary EVs may indicate podocyte damage and have a direct relationship with the pathology of IgAN and MGN. Further studies are needed to confirm these results and determine the diagnostic value of these markers.
#2229 miR-186, a potential noninvasive diagnostic biomarker of Membranous nephropathy in urinary microparticles
Authors: Farzamikia Negin , Ardalan Mohammad Reza , Zununivahed Sepideh
Published: May 2024

Background and Aims

Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome, and is associated with podocyte damage and proteinuria. Invasive biopsy is the gold-standard diagnostic method for this disease. The use of specific biomarkers, such as microparticles (MPs) originating from damaged podocytes released in a patient's urine, has been proposed as an early, noninvasive, and repetitive diagnostic method. According to the previous studies, MPs derived from podocytes are present in the urine of patients with different glomerulonephritis, such as diabetic nephropathy, lupus nephritis, renal injury in preeclampsia, and renovascular hypertensive disorders. The analysis of urinary microparticle-derived miRNAs from patients with kidney diseases can help detect diagnostic biomarkers. This study aimed to analyze podocyte damage-related miRNAs in MN, miR-30c, miR-135, and miR-18 in the urinary MP of MN patients to identify appropriate candidate biomarkers for MN

Method

Urine samples from 30 patients with membranous nephropathy and 16 healthy individuals were collected to extract podocyte MPs using ultracentrifugation. Characterization of these particles was determined using the specific protein marker of MPs, TSG-101, and the podocyte-specific marker Nephrin, by western blotting, and SEM was used to check the size and morphology. The expression levels of microRNAs extracted from podocyte MPs, miR-30c, miR-135, and miR-186, were also evaluated by real-time PCR.

Results

The evaluation of the characteristics of MPs showed that there were many particles with a size of more than 100 nm in the urine sample, and there were higher levels of the specific markers TSG-101 and Nephrin in the urine samples of MGN patients than in the control samples (P < 0.001). The expression level of miR-186 was compared between the three studied groups and based on the results of the expression of this miRNA in the group of membranous nephropathy patients compared to healthy people group, there was a significant increase in expression (P = 0.000)

Conclusion

This study showed that although the expression levels of miR-186 in podocyte MPs samples extracted from the urine of patients with MN were significantly changed compared to the studied controls, more studies should be performed to determine the diagnostic values.
#2088 Renal outcome, cardio-vascular events and infections in patients with lupus nephritis: MassiLUP cohort 2001-2022
Authors: Goupille Berangere , Resseguier Noemie , Torrents Julia , Bataille Stanislas , Bobot Mickaël , Brunet Philippe , Burtey Stephane , Corthier Alice , Faraut Julien , Sallee Marion , Daniel Laurent , Jourde-Chiche Noemie
Published: May 2024

Background and Aims

Most epidemiological studies in lupus nephritis (LN) report the risk of end-stage kidney disease (ESKD) (10-20% of patients at 10-15 years in developed countries), but less data is available on the long-term risk of chronic kidney disease (CKD), even though CKD is a major risk factor for morbidity and mortality. While immunosuppressive therapy for LN aims to reach and maintain remission in order to prevent CKD, it also exposes patients to cardiovascular, infectious and neoplastic adverse events. We conducted a retrospective cohort study to evaluate survival without CKD and adverse events in patients with LN.

Method

The MassiLUP cohort comprises all patients who underwent a kidney biopsy for a first flare of LN between 2001 and 2022 in the University Hospital of Marseille, France. We assessed patient survival, renal survival and survival without CKD (defined by an estimated glomerular filtration rate < 60 mL/min/1.73 m2), without cardiovascular event, without severe infection (requiring hospitalization, or zoster), and without cancer.

Results

A total of 168 patients (82.7% female; mean age 33 years; mean serum creatinine 102 µmol/L at the time of the first kidney biopsy) were included, with a mean follow-up of 9.6 ± 5.7 years. One (0.6%) patient had class I LN (ISN/RPS 2003 classification), 17 (10.1%) class II LN, 45 (26.8%) had class III (± V) LN, 73 (43.5%) had class IV (± V) LN, 29 (17.3%) patients had pure class V LN; 3 biopsies could not be classified.

Four patients died during the follow-up (3 of severe infections and 1 of stroke); 41 (24.4%) patients developed CKD, among whom 19 (11.3%) patients reached ESKD; 34 (20.2%) patients presented a cardiovascular event, 59 (35.1%) a severe infection, and 12 (7.1%) a cancer.

Survival rates without CKD were 82.9%, 74.6% and 67.3% at 5, 10 and 15 years, respectively.

Survival rates without ESKD were 94.4%, 88.6% and 79.9% at 5, 10 and 15 years, respectively.

Survival rates without cardiovascular event were 85.7%, 77.3% and 75.5% at 5, 10 and 15 years, respectively.

Survival rates without severe infection were 76.3%, 63.8% and 51.8% at 5, 10 and 15 years, respectively.

Survival rates without cancer were 96.3%, 92.9% and 85.6% at 5, 10 and 15 years, respectively.

Conclusion

Despite free access to treatment and care in France, the long-term prognosis of patients with lupus nephritis remains burdened by both a risk of CKD and ESKD, and a significant risk of cardiovascular and infectious events. This calls for continued efforts to improve therapeutic strategies, both in terms of efficacy and toxicity, and to strengthen the therapeutic alliance in the care of patients with LN.
#464 Survey results on the utility of the Renal Risk Score and Histopathological Classification of ANCA-glomerulonephritis
Authors: Uzzo Martina , Berden Annalies , Emmi Giacomo , Floyd Lauren , Jennette Charles , Kronbichler Andreas , Neumann Irmi , Vaglio Augusto , Wiech Thorsten , Jayne David R W , Brix Silke , Bajema Ingeborg
Published: May 2024

Background and Aims

The importance of kidney biopsy in ANCA-associated glomerulonephritis (AAV) is widely recognized: both the Berden classification and the ANCA renal risk score (ARRS) are widely used and reliable predictors of prognosis. AAV phenotypes, outcomes and treatment have changed over the last decades: whether and how the existing classification and ARRS need to be updated is a matter of discussion. A survey to assess the current use of the classification and ARRS in clinical practice was conducted on behalf of the newly formed “Working Group on classifications and risk scores”.

Method

An online survey was sent to the active members of the European Vasculitis Society (EUVAS) between September 13th and September 27th, 2023. The survey used an internet platform, contained 12 multiple-choice and 2 open questions and results were analyzed anonymously.

Results

76 of 295 EUVAS members replied to the questionnaire: 40 (52.6%) were nephrologists, 25 (32.9%) rheumatologists, 4 (5.3%) pathologists and 7 (9.3%) “others”. Their level of expertise was high, with 61 (80.3%) physicians encountering more than 10 new-diagnosed AAV patients per year. A total of 64 (84.2%) responders usually performed a kidney biopsy in suspected AAV patients, considering the pathological examination a useful tool for prognosis (89.5%), diagnosis (85.5%) and treatment (81.6%). More than 90% of responders indicated they discuss kidney biopsy results in a multidisciplinary meeting involving both clinicians and pathologists. Both the Berden classification and the ARRS are known by around 70% of experts in the field; the first being commonly used by clinicians in everyday practice (70.1% vs 52.5%, p = 0.08). Both systems were considered useful on a scale from 0 to 10, with a median grade of 7 [(IQR 5-8) vs (IQR 6-8), p = 0.21].

Suggested improvements were further standardizations and simplicity. New parameters (e.g., extraglomerular involvement, laboratory and clinical features) and biomarkers should be considered for future inclusion.

Conclusion

A survey assessing the current use of the Berden classification and ARRS in clinical practice showed that both systems are widely used among vasculitis clinicians and that the ideal system should be able to guide treatment decisions. The validation of pathological systems for targeted treatment decisions is an unmet need.
#1356 Kidney phenotype in interstitial lung disease associated with ANCA-vasculitis: European Multicentre Study
Authors: Chalkia Aglaia , Jones Rachel B , Kamath Ajay , Mohammad Aladdin , Monti Sara , Mukhtyar Chetan , Petrakis Ioannis , Petras Dimitrios , Smith Rona M , Stylianou Kostas , Vassilopoulos Dimitrios , Jayne David R W
Published: May 2024

Background and Aims

Interstitial lung disease (ILD) in ANCA-associated vasculitis (AAV) has the appearance of a progressive fibrotic disease on imaging and primarily affects the interstitial lung compartment and is usually associated with MPO-ANCA. Whether patients with AAV-ILD display a similar fibrotic pattern in their kidneys is unclear.

Method

A European multicentre retrospective study included patients with AAV-ILD. The diagnosis of ILD was confirmed by a CT chest pattern of usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), organising pneumonia or chronic hypersensitivity pneumonia. We aimed to determine if kidney involvement in AAV-ILD exhibited a more fibrotic pattern compared to AAV-related nephritis without ILD, using data from the Cambridge AAV cohort.

Results

135 patients with AAV-ILD were included; 94 (70%) had also kidney involvement, in whom the mean age was 71 ± 11 years and 87% MPO-ANCA positive. The ILD diagnosis preceded AAV in 17%, 64% presented concurrently with kidney involvement, 20% with pulmonary haemorrhage. The most common lung radiological pattern was UIP (67%).

At presentation, the median glomerular filtration rate (GFR) was 27 ml/min per 1.73 m2 (interquartile range 12-50), with a median albumin-to creatinine ratio 23 mg/mmol (IQR 10-97). Among 72 patients with available kidney biopsy, the most prevalent Berden class was focal in 45%, followed by mixed in 33%, crescentic in 18% and sclerotic in 4%. Although, the prevalence of Berden classes did not significantly differ between ILD-nephritis and no ILD-nephritis groups, the former group had a higher baseline GFR (p = 0.05), lower albuminuria level (p = 0.002), higher percentage of normal glomeruli (p = 0.027), lower glomerular necrosis percentage (p = 0.002) and higher interstitial fibrosis score (p = 0.049). Within five years, the ILD-nephritis group demonstrated renal recovery, as indicated by an adjusted mean delta GFR of 13.4 ml/min per 1.73 m2, without a significant difference compared to the no ILD-nephritis group. Over a median follow-up of 4.9 years (IQR 2-9), the progression to end-stage kidney disease (ESKD) was comparable between the groups. However, notably, the ILD-nephritis group experienced significantly poorer survival rates (mean 10.9 years vs 17.9 years, log-rank p < 0.001).

Conclusion

In AAV-ILD, kidney involvement is often characterized by fewer inflammatory and a higher prevalence of fibrotic lesions than on non-ILD-AAV. Despite initial differences in renal pathology and kidney function between these groups, both demonstrated similar risks of progressing to ESKD. Nevertheless, it's crucial to underscore the significant influence of ILD on the overall outcomes of AAV patients with kidney involvement.
#71 Dysregulation of ITGAM and ITGB2 in the pathogenesis of diabetic kidney disease—results from bioinformatics analysis and in vitro studies
Authors: Yap Desmond , Xie Ruiyan , Jason Sher Ka Ho , Tang Sin Yu Cindy , Wu Qiongli
Published: May 2024

Background and Aims

Activated neutrophils can release web-like chromatin structures known as neutrophil extracellular traps (NETs), but their roles in the immunopathogenesis of diabetic kidney disease (DKD) remains elusive.

Method

The characteristic NETs associated targets of differentially expressed genes (DEGs) from human kidney biopsy datasets of patients with DKD (GSE30528 and GSE30529) were identified by machine learning method (LASSO and SVM-RFE). The genes expression was further validated using kidney biopsy dataset of GSE142025. The most abundant single cell of the targets in DKD was further selected by single-nucleus RNA sequencing datasets (GSE131882). Predictive pathway network of targeted genes was constructed using GENEMANIA database. The expressions and potential signaling pathway of these candidate genes were validated using flow cytometry and ELISA.

Results

Three predicting NETs related genes (ITGAM, ITGB2 and TLR7), identified by machine learning algorithms, which all showed significant upregulation in both glomerular and tubulointerstitial compartments in human DKD kidney samples. Single-cell analysis suggested that ITGAM, ITGB2 and TLR7 were most enriched in leucocytes. DKD patients (n = 18) showed significantly higher activated neutrophils as well as increased expression of ITGAM and ITGB2 compared to healthy controls (HCs, n = 9). DKD patients also exhibited higher serum levels of IL6 but lower IL-10 than HCs (all p < 0.01). The significant network of IL10, IL6, ITGAM and ITGB2 was generated. This network might be associated with leukocyte activation, macrophage activation, JAK-STAT pathway, acute inflammatory response and lymphocyte immune response (all p < 0.05).

Conclusion

Aberrant ITGAM and ITGB2 expressions in activated neutrophils contribute to DKD pathogenesis and may serve as novel therapeutic targets for DKD.
#314 Systemic lupus erythematous (SLE) and isolated multiple sclerosis: analysis of BAFF—VAR variant on gene TNSF13B
Authors: Orfeo Chiara Alessia , Vezzani Valeria , Capone Martina , Bonomini Mario
Published: May 2024

Background and Aims

We report a case of young a woman (33 years old) affected by SLE since 2007. In this year, a renal biopsy showed class IV lupus nephritis and the patient received corticosteroids and immunosuppressant for 3 years. The patient remained thereafter in disease remission with normal renal function, no proteinuria and normal complement levels.

In 2013 the patient performed brain MRI for sudden hearing loss. The MRI showed a pattern compatible with isolated multiple sclerosis (RIS), confirmed on subsequent radiographic checks. In 2023, due to the initial onset of renal failure, a new re-staging biopsy showed microscopic aspects compatible with class I/II lupus nephritis (INS/RPS Classification 2004, 2018); the activity index calculated with SLEDAI—2K was +4.

A new brain MRI carried out without onset of new symptoms showed a new hyperintense region at the level of the head of the right caudate nucleus and enlargement of the intrasellar CSF content as per the condition of a “partially empty” sella.

A genetic variant of the TNFSF13B gene was therefore suspected, since it is involved in encoding the cytochine and drug target B-cell activating factor (BAFF), associated with multiple sclerosis as well as SLE.

We searched for the genetic variant in order to undertake target therapy early in our patient.

Method

We performed PCR amplification and direct sequencing of all coding exons plus all the intron-exon junctions of the analyzed gene, by automatic sequencer with SeqStudio Genetic Analyzer (analytical sensitivity and specificity >99%).

Results

We found the heterozygous presence of the BAFF-var variant in the 3' UTR region of the TNFSF13B gene (Heterozygous genotype for BAFF-var). This variant involves an insertion/deletion (GCTGT>A) at the level of the 3' UTR region with consequent production of an alternative polyadenylation site (APA). This APA leads to the formation of a shorter transcript (BAFF-var mRNA) which causes greater production of the encoded protein compared to the wild-type transcript (BAFF-WT mRNA).

Conclusion

The molecular analysis conducted highlighted the presence of the BAFF-var variant in heterozygosis which leads to increased levels of soluble BAFF in the serum, with consequent up-regulation of humoral immunity. It is reported in the literature1 that this variant is associated with both Multiple Sclerosis and SLE and may represent a valid therapeutic target being treatable with the monoclonal antibody Belimumab.
#2890 Role of alternative pathway of complement system in membranous nephropathy: a study from STARMEN clinical trials
Authors: León-Machado Lina María , Maldonado Maria , Rivera Jorge Enrique Rojas , Ortega Esther , Praga Manuel , De Jorge Elena Goicoechea , Juarez Gema Maria Fernandez
Published: May 2024

Background and Aims

Membranous nephropathy (MN) is an antibody-mediated autoimmune disease characterized by glomerular immune complexes containing complement components. A recent animal model of PLA2r antibody-induced MN induced has demonstrated the crucial role of complement pathway, although is still unclear which complement pathway is most involved in its pathogenesis

This study aimed to explore the role of alternative pathway of complement cascade in a cohort of patients from STARMEN clinical trial.

Method

We analyzed longitudinal plasma samples from 51 patients from STARMENT cohort stored in a biobank. Samples were stored at enrollment and longitudinally throughout the follow up at 3, 6, 9, 12, 18 and 24 months. We measured the circulating plasma levels of C3, FB, FH, FHR1, FHR2 and FHR5 in every time.

Results

Fifty-two patients with a mean age of 56 ± 10 years and 60% male were included. 44% were treated with tacrolimus+Rituximab and 56% with ponticelli regimen. The basal creatinine was 0.9 ± 0.3 mg/dl, median proteinuria/day was 8.8 g/day (IQR 5.7-11.6 gr/day) and serum albumin of 2.6 g/dl (IQR 2.3-2.9 g/dl). All patients were followed-up for two years. Thirty-four patients achieved complete remission (CR), 11 patients partial remission (PR) and 15 did not respond (including relapse).

During active disease, the mean concentration of FH, FHR-1 and FHR-2 were significantly increased compared with remission status (complete or partial). We did not find different in other factors: FB or FHR-5. Moreover, a positive correlation was observed between FH and FB with C3. There were no differences according to treatment arm.

PLA2r antibodies tested positive in 68%. The median of baseline anti-PLA2R title levels was 80 RU/ml (IQR 43-141). Circulating plasma levels of FHR1 at baseline were significantly higher in PLA2r testing negative vs positive patients (199 ± 108 vs 249 ± 41 µg/ml, p = 0.021). This significant difference was present when remission was achieved (205 ± 97 vs 264 ± 49 µg/ml, p = 0.023). Similar tendency was observed for FB.

Conclusion

These data provide evidence of complement system activation through the alternative pathway in membranous nephropathy. We know that different subtypes of IgG are behind the different antibodies-induced MN induced, and that every subtype active different complement pathway. The results of this study lead to speculate that not all the antigens that induced MN active complement pathway in the same way.
#2006 CircMTND5 participated in tubulointerstitial fibrosis progression of lupus nephritis by binding with A1CF
Authors: Zhou Hua
Published: May 2024

Background and Aims

lupus nephritis (LN) is the most common and severe complication of systemic lupus erythematosus (SLE). CircRNA MTND5 participated in the pathogenesis of LN by sponging miR6812. However, it remains unclear what RNA binding role of circMTND5 play in LN. We aim to investigate whether circMTND5 can interact with RBP in the development and progression in LN, and to clarify the corresponding mechanisms.

Method

A1CF, a RNA binding protein, E-cadherin, α-SMA, TGF-β, and Fibronectin were analyzed by immunohistochemistry on paraffin-embedded section of LN patients and NC kidney tissues. The above parameters and circMTND5 were also examined in Fcgr2b-/- spontaneous LN mice kidneys by Western blotting and qPCR. In human kidney (HK) -2 cells, the binding of circMTND5 to A1CF protein was examined by RNA immunoprecipitation (RIP) assay. After knockdown in HK-2 cells and overexpression in hTGF-β stimulated HK-2 cells, we examined the all above indices.

Results

the expression of A1CF was down-regulated in the kidneys of LN patients and was localized in tubular epithelial cells. E-cadherin was down-regulated while α-SMA was up-regulated. The expression of circMTND5 was down-regulated in kidneys of Fcgr2b-/- spontaneous LN mice. In HK-2 cells, the binding of circMTND5 to A1CF was confirmed by RIP. A1CF and E-cadherin were down-regulated, while α-SMA, TGF-β and FN were up-regulated in HK-2 cells with knockdown of circMTND5. The overexpression of circMTND5 reverted the changes of the those above parametered induced by hTGF-β in both mRNA and proteins levels.

Conclusion

The expression level of circMTND5 in renal tissue of LN mice was downregulated. CircMTND5 might play an important role in tubulointerstitial fibrosis of lupus nephritis by binding with A1CF protein.
#1641 Assessing long-term prognosis in patients with glomerular disease: nephrotic syndrome versus nephrotic range proteinuria comparison
Authors: Stefan Gabriel , Stancu Simona , Zugravu Adrian Dorin , Petre Nicoleta
Published: May 2024

Background and Aims

Although there is considerable research on the role of proteinuria in the progression of chronic kidney disease, a direct comparison between biopsy-diagnosed glomerular disease (GD) patients presenting with nephrotic syndrome (NS) and those with nephrotic range proteinuria (NRP) is lacking. Our study aims to bridge this gap by comparing the long-term outcomes of patients with NS and NRP.

Method

We conducted a unicentric retrospective study on 240 kidney biopsy-proven GD patients (median age 50 years, 65% men, median eGFR 58 mL/min, median proteinuria 6.0 g/24 h), tracked from 2010-2015 until end-stage kidney disease (ESKD), death, or study end in January 2022.

Results

The median follow-up was 8.8 years. Diagnoses were predominantly nonproliferative (53%), proliferative (25%) nephropathies, diabetic nephropathy (12%), and paraprotein diseases (10%).

NS was observed in 141 (59%) patients, presenting more frequently with arterial hypertension (61 vs 43%, p 0.001), higher eGFR (64.9 vs 51.5 mL/min, p 0.001), increased proteinuria (6.4 vs 5.4g/24 h, p 0.01), and dyslipidemia (serum cholesterol 316 vs 251 mg/dL, p 0.001; serum triglycerides 226 vs 184 mg/dL, p 0.001) than NRP patients.

NRP patients more often had proliferative (30 vs 22%) GD and diabetic nephropathy (22 vs 5%) ; their renal chronicity score was higher (2 vs 0, p 0.001).

ESKD endpoint occurred in 35% NS and 39% NRP patients (p 0.4). The cohort's mean kidney survival time was 8.2 years. In multivariate analysis, NS (HR 1.79, 95% CI: 1.09, 2.94), lower eGFR (HR 0.97, 95% CI: 0.96, 0.98), higher renal chronicity score (HR 1.12, 95% CI: 1.02, 1.23), and diabetic nephropathy (Ref, p 0.001) were associated with ESKD.

64 patients (27%) died, 73% post-kidney replacement therapy initiation, mostly from cardiovascular disease (63%). Mortality between proteinuria forms showed no difference. Multivariate analysis found lower eGFR (HR 0.98, 95% CI: 0.97, 0.99), higher Charlson comorbidity score (HR 1.38, 95% CI: 1.17, 1.64), and diabetic nephropathy (Ref, p 0.01) associated with mortality.

Conclusion

Our study found no difference in all-cause mortality between NS and NRP in glomerular diseases. However, adjusted analysis revealed poorer kidney survival for NS patients, emphasizing the need for personalized management to improve renal prognosis.
#626 C3 glomerulonephritis and thrombotic microangiopathy—a prospective observational study
Authors: Shankar Mythri , Siddalingappa Ranjitha , C.G Sreedhara , A Kishan , Tenannkore Karthik
Published: May 2024

Background and Aims

Complement mediated TMA (cTMA) and complement component 3 glomerulonephritis (C3GN) are two distinct complement mediated kidney diseases. cTMA is characterized by acute kidney injury, thrombocytopenia and microangiopathic hemolytic anemia. C3GN results from uncontrolled activation of the alternative complement pathway leading to the deposition of C3 in the glomerulus. We sought to describe characteristic differences between these two conditions in a large cohort of patients from Bengaluru, India.

Method

All cases of cTMA and kidney biopsy proven C3GN from 2019-2022 at a tertiary care centre in India were included. Patients with C3GN had persistently low C3 for more than 12 weeks and no identifiable source of infection. All patients received protocolized medical therapy; patients with C3GN were treated with steroids and cyclophosphamide, while those with complement mediated TMA received plasmapheresis in addition to cyclophosphamide and steroids. Protocolised medical management (renin-angiotensin-aldosterone inhibition and diuretics) was provided in both the cases. Demographic, clinical and lab parameters were reported and compared.

Results

A total of 25 cTMA cases and 19 C3GN cases were included in the study. Both C3GN (52.7%) and cTMA (48%) were more common in males. Patients with C3GN typically presented in the third decade of life while cTMA cases presented in the fourth decade. Secondary hypertension was common in the cTMA group (92% vs 78.9%, compared to C3GN). 60% of patients with cTMA had either recent or current infection compared to 21.1% of C3GN patients (P = 0.04). The majority of cTMA cases had IFTA of <25% (84%) compared to C3GN (57.9%) although this was not statistically significant. Both C3GN and cTMA most commonly presented as rapidly progressive kidney failure and acute kidney injury. A total of 76% of patients in the cTMA group required kidney replacement therapy as compared to 47.4% in the C3GN group (P = 0.009). 44% of cTMA cases had anti factor H antibody positivity compared to 15.8% of C3GN patients (P = 0.02). Finally, 44% of cases in cTMA group had complete recovery compared to 47.4% in C3GN group at the end of 2.8 years of followup.

Conclusion

Although both conditions result from dysregulation of the alternative pathway, there are several important clinical characteristic differences between patients with cTMA and C3GN including presence or absence of secondary hypertension, concurrent infection, anti-factor H positivity and requirement of kidney replacement therapy. This information may be helpful to inform both diagnosis and prognosis for patients presenting with a complement mediated kidney disease.
#1933 Urinary proteomics identifying the novel biomarker associated with crescentic glomerulonephritis
Authors: Zhang Shuo , Chen Xin , Xu Jiatong , Hu Yu-Ting , Wang Ying , Xia Peng , Qiu Bintao , Chen Limeng
Published: May 2024

Background and Aims

As a severe progressive acute renal injury, crescentic glomerulonephritis requires timely pathology diagnosis and treatment. New non-invasive biomarkers will be crucial when the renal biopsy is not available or unacceptable. Urinary proteomics, specifically data-independent acquisition (DIA) proteomics, might provide some potential indicators.

Method

Urine proteomics examination was on patients with crescentic glomerulonephritis(n = 15), chronic glomerulonephritis (n = 15), acute kidney injury (AKI) without glomerular crescentic(n = 10), and 15 healthy controls. The crescentic glomerulonephritis group is the patients with extensive glomerular crescents over 50%. We performed LC-MS/MS analysis to identify differentially expressed proteins (DEPs), Ingenuity Pathway Analysis (IPA), and the proteome map for significant pathways and crucial proteins among patients and controls. The signature proteins were validated using enzyme-linked immunosorbent assay (ELISA) analysis.

Results

A total of 55 population, males occupied 45.45%, with the average age being 53 ± 13 years old. A volcano plot among crescentic glomerulonephritis and control groups is in Fig. 1. IPA analysis showed that neutrophil degranulation and complement cascade were the top two pathways in crescentic glomerulonephritis but not in the healthy and nephritis groups. The activated neddylation pathway in patients with crescentic glomerulonephritis compared with AKI patients. After integrating the DEPs among three groups via the Venn plot, we observed eight DEPs significantly associated with the crescentic glomerulonephritis, among which Coagulation factor V (F5), Phospholipid transfer protein (PLTP), and Alcohol dehydrogenase 1C (ADH1C) were significant proteins. Biomarker analysis showed the area under the curve values for predicting crescentic glomerulonephritis were 0.867, 0.851, and 0.815, respectively (P < 0.001).

Conclusion

Urine proteomics holds promise in identifying the crescentic glomerulonephritis patient, thus providing a potential value as a noninvasive biomarker.