bluuebunny/crossref_metadata_2025_split huggingface dataset:
#1437 Renal expression pattern of the relaxin receptor, RXFP1, and effects of the RXFP1 agonist, AZD5462, on renin in non-human primates and humans
Authors: Lal Mark , Ryberg Erik , Althage Magnus , Bergström Fredrik , Hansen Pernille B L , Pettersen Daniel , Connolly Kat , Rosenmeier Jaya 
Published: May 2024

Abstract

Background and Aims
RXFP1 is a G protein-coupled receptor (GPCR) for the pregnancy hormone, relaxin. While preclinical studies, performed primarily in rodent, describe beneficial effects of this pleiotropic peptide across several organ systems, there has been a disappointing lack of success in translating these observations into clinical benefit. To provide a potential pharmacological explanation accounting for this translational gap, the aim of this study was thus to thoroughly evaluate RXFP1 expression across species and tissues as well as to evaluate the renal-intrinsic effects of the RXFP1 agonist, AZD5462.

Method
Unbiased bioinformatic analysis of several gene expression databases was used as a first approach to compare RXFP1 tissue-level expression between rodent and human. Experimental validation was subsequently performed using scRNAseq, RNAscope and immunohistochemistry on mouse, rat, non-human primate (NHP) and human kidney. The putative renal target engagement effects of RXFP1 agonism were assessed by determining the acute and chronic effects of the RXFP1-selective small molecule agonist, AZD5462, on plasma renin concentrations in both NHPs and in a Phase 1 randomized, single-blind, placebo-controlled study in healthy humans.

Results
RXFP1 was identified as one of the most highly expressed GPCRs in human and NHP kidney glomeruli. Specifically, by multiple assays, we identified glomerular endothelial cells as the principal cell type expressing RXFP1. This observation is in stark contrast to mouse and rat kidney, where RXFP1 was not readily detected. AZD5462 administered orally to NHPs and healthy human participants elicited an early and sustained dose-dependent increase in plasma renin concentration, and in humans an additional decline in serum creatinine.

Conclusion
Human RXFP1 kidney glomerular expression is conserved with NHPs but not rodent, thus highlighting the translational and pharmacological challenges in studying RXFP1/relaxin biology across species. The concordant ability of AZD5462 to induce elevations in renin and reduction in serum creatinine, together with relaxin's reported renal-hemodynamic activity in humans, may underlie a previously unappreciated renal-intrinsic RXFP1 target engagement mechanism driving its hemodynamic and renal effects. The potential therapeutic benefits of RXFP1 agonism are the subject of on-going clinical trials in heart failure patients.
#1343 Microfluidic kidney tubuloids-on-a-chip for improved drug translation
Authors: Kurek Dorota , Torregrosa Manuel Caro , Admiraal Jade , Gijzen Linda , Grasegger Julia , Lanz Henriëtte 
Published: May 2024

Abstract

Background and Aims
Current 2D in vitro models of renal epithelium lack key features of the in vivo setting, such as tubular structure and perfusion, resulting in low translatability to human situations and failure in clinical translation. Advanced renal in vitro models are of great importance to study kidney function under healthy and diseased conditions. Kidney tubular epithelial organoids, called tubuloids, are three-dimensional multicellular structures that recapitulate tubular function and have been used to model genetic, metabolic, and infectious renal diseases. To increase physiological relevance of the tubuloids, they can be integrated into an organ-on-a-chip system. This microfluidic technique is becoming increasingly recognized as a valuable tool for adding physiologically relevant cues to traditional cell culture including long-term gradient stability, continuous perfusion, and interaction with other cell types such as vasculature.

Method
Here, we introduce the OrganoPlate microfluidic platform, which can accommodate up to 64 independent microfluidic chips in a microtiter plate format, allowing the growth of 64 independent kidney tubuloid-derived barrier tissues in the form of perfused tubules. To this end, tubuloids derived from adult kidney tissue were plated as single cells in the OrganoPlate against an extracellular matrix (ECM). These renal tubules can be formed in just four days of culture in the device showing rapid and reproducible cell polarization, tight junction formation, proper expression of renal markers and functional transport.

Results
When integrated into an OrganoPlate system, kidney tubuloids form leak-tight, perfusable tubes with stable Trans Epithelial Electrical Resistance (TEER) and are suitable for high-throughput screening of compound effects through assessment of barrier integrity by use of OrganoTEER and by real-time imaging of transport. OrganoPlate grown kidney tubes treated with Pgp inhibitor Verapamil show significant reduction of Rhodamine123 transport through kidney tubule barrier which confirms show stable activity of Pgp transporter and usability of the model in studying renal drug clearance.

Conclusion
Our results demonstrate the suitability of our in vitro microfluidic kidney tubuloid-on-a-chip model in mimicking key physiological aspects of the kidney and offer new ways for studying organ physiology and renal disease mechanisms, toxicity screening, and personalized medicine. Additionally, the use of animal models, as well as the costs of drug development, can be reduced.
#1949 Comparison of two commercial available primary human mesangial cell clones reveal differences
Authors: Johansson Alva , Boi Roberto , Narasimhan Gayathri , Ebefors Kerstin 
Published: May 2024

Abstract

Background and Aims
Mesangial cells and their matrix form the central stalk of the glomerulus but is often overlooked when studying glomerular function. The cells are however highly involved in glomerular function and crosstalk between the different cell types of the glomerulus. They are important in onset and progression of several glomerular diseases, such as IgA nephropathy and diabetic kidney disease.
As mesangial cells have several functions and are involved in glomerular disease they are often used for in vitro work studying response to various stimuli and downstream signaling. This includes changes in the production and regulation or their matrix, proliferation, contractility, protein expression and release of different inflammatory mediators such as cytokines and growth factors [1]. Using primary cells when doing in vitro work is usually considered the best option, but there might be differences between origin of cells in their response and physiology.
For this study, our aim was to compare two types of commercially available primary human mesangial cells from Cell systems (CS) and Novabiosis (NBS).

Method
For characterization of the CS and NBS mesangial cells, gene expression of commonly used mesangial cell markers, including KRT19, ACTA2, PDGFRA and PDGFRB, was analyzed with real time qPCR. Staining of smooth muscle actin was done in order to compare the phenotype of CS and NBS. To compare the cells, differences in protein expression were determined using proteomics. CS and NBS Cells were cultured in the same way and were also treated with PDGF-BB for 24 h to compare with untreated control. For further comparison, proliferation assay was used to compare proliferation after treating cells with PDGF-BB for 24 h.

Results
Both sources of cells expressed all markers, but there was a difference in level of gene expression. CS cells showed higher expression than NBS cells for all markers, apart from ACTA2. NBS cells had a more stellate phenotype whereas the CS cells were more elongated. There was a difference in proteins expressed by CS and NBS mesangial cells from our proteomics. The level of upregulation of proteins seen with proteomics was stronger for CS than NBS cells when treated with PDGF-BB. The number of proteins upregulated was also higher for CS than NBS cells. Both mesangial cell types had increased proliferation when treated with PDGF-BB, however CS cells were seen to grow faster in cell culture and seemed to be more responsive to the treatment with PDGF-BB.

Conclusion
In conclusion, this study compares two commercially available primary human mesangial cells and show that there is a difference between the two. The cell types react differently when treated with PDGF-BB and has some difference in what proteins they express. This needs to be considered when conducting cell culture experiments with mesangial cells, depending on what the aim and focus for the study is.
#2327 Extent of proteinuria in autosomal dominant Alport syndrome compared to X linked Alport syndrome
Authors: Gonçalves Pedro Lisboa , de Faria Vitoria Paes , Furlano Monica , Almeida Catarina , Sampani Erasmia , Teran Melissa Pilco , Viera Elisabet , Fayos Leonor , Pybus Marc , Aza Miriam , Ars Elisabet , Torra Roser 
Published: May 2024

Abstract

Background and Aims
Alport syndrome (AS), as first described by Arthur Cecil Alport in late XIX century, encompasses a clinical picture of neurosensorial hypoacusia, ocular abnormalities, hematuria and proteinuric kidney disease progressing to end-stage kidney disease in the young adulthood. Differently from X-linked and autosomal recessive AS, autosomal dominant AS (ADAS), a more recently recognized entity, whose prevalence based on populational studies may be near to 1%, generally presents with a milder kidney involvement and with negligible extrarenal features. Nevertheless, some of these patients progress to chronic kidney disease (CKD) category G5, with marked intra and interfamilial variability.
Although hematuria is almost universally present all three inheritance patterns, the magnitude of proteinuria, a reliable prognostic marker of the X-linked form has not been thoroughly studied in ADAS.
We aimed to compare the extent of proteinuria between patients with X-Linked and autosomal dominant AS.

Method
Retrospective registry data on type of Alport hereditary pattern and spot urine protein to creatinine ratio per CKD category were collected. The 2021 CKD-EPI formula for calculation of glomerular filtration rate (eGFR) was used. Non-parametric test was used to analyze variables that did not follow normal distribution.

Results
We analyzed proteinuria and eGFR of 127 patients with Alport Syndrome. Information on patient gender, hereditary pattern and gene involved is illustrated it Table 1. Increased proteinuria was observed with CKD progression in all categories (p &lt; 0.05). Within each CKD category, X-linked males had greater median proteinuria followed by, X-linked females and autosomal dominant patients (Table 2 and Fig. 1).
No difference in median proteinuria was observed between X-linked females and those with autosomal dominant inheritance throughout CKD categories G1, G2, G4 and G5 (p = 0.142, 0.878, 0.327, 0.909 respectively). Difference in median proteinuria between X-linked females and autosomal dominant inheritance revealed statistical significance in CKD category G3 (p = 0.034), however the small sample size in this group must be taken into account.

Conclusion
Pathogenic variants in COL4A3, COL4A4, and COL4A5 are all causes of CKD, and proteinuria serves as a hallmark of disease progression. However, the extent of proteinuria in ADAS is significantly lower than that observed in XLAS. Additionally, some ADAS patients develop CKD with only albuminuria. While there is still much to be understood about this common condition, the renal mechanism of damage in ADAS appears to differ definitively from that in XLAS or ARAS.
#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

Abstract

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

Abstract

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

Abstract

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 &lt; 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

Abstract

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.