Empagliflozin reduces renal calcium oxalate deposition in hyperoxaluria rats induced with ethylene glycol-ammonium chloride.

A retrospective study reported that empagliflozin reduced the risk of urinary stone events in patients with diabetes mellitus. To further investigate empagliflozin's potential, we conducted an animal experiment to determine whether empagliflozin can prevent renal stone formation in hyperoxaluria rats. Hyperoxaluria rat models were constructed by administrating 0.75 % ethylene glycol and 1 % ammonium chloride in water. The empagliflozin-treated rats were gauged with empagliflozin at different concentrations, and their body weight and blood sugar data were recorded. After 30 days of treatment, we obtained 24-h urine, kidney, and blood samples. The urine samples were subjected to component detection. Blood samples were prepared for component detection and cytokines detection. Renal samples were subjected to von Kossa staining, transmission electron microscopy, immunohistochemistry, and transcriptome sequencing analysis. Results showed that in empagliflozin-treated hyperoxaluria rats, renal crystal deposition and mitochondria injury, urinary concentration, and excretion of oxalate were significantly decreased. Additionally, plasma levels of VEGF, IL-2, IL-1ß, and MCP-1 were decreased. Immunohistochemistry showed that renal expression of KIM-1, MCP-1 was significantly decreased in empagliflozin-treated hyperoxaluria rats. Transcriptome sequencing of renal tissue represented that 25 genes were down-regulated while 12 were up-regulated in empagliflozin-treated hyperoxaluria rats. These regulated genes were mainly enriched in fatty acid metabolism, insulin resistance, muscle contraction, bile secretion, and parathyroid metabolism. Our animal experiments found that empagliflozin could reduce urinary concentration and excretion of oxalate and inhibit renal inflammation, then abating renal calcium oxalate deposition in hyperoxaluria rats in a non-diabetic state.

Oxalate-upregulated annexin A6 promotes the formation of calcium oxalate kidney stones by exacerbating calcium release-mediated oxidative stress injury in renal tubular epithelial cells and crystal-cell adhesion.

Kidney stones result from abnormal biomineralization, although the mechanism behind their formation remains unclear. Annexin A6 (AnxA6), a calcium-dependent lipid-binding protein, is associated with several mineralization-related diseases, but its role in kidney stones is unknown. This study aimed to explore the role and mechanism of AnxA6 in calcium oxalate (CaOx) kidney stones. An in vitro model in which renal tubular epithelial cells (RTECs) were treated with 1 mmol/L oxalate was established, and AnxA6 protein and mRNA expression were examined. Genetic engineering, drug intervention, and biochemical assays were used to investigate the role of AnxA6. The results revealed that AnxA6 was significantly overexpressed in the CaOx model. AnxA6 knockdown in RTECs reduced oxalate-induced oxidative stress, ROS accumulation, and mitochondrial damage, whereas AnxA6 overexpression exacerbated these effects. Blocking ryanodine receptor-mediated calcium release reversed AnxA6-induced oxidative damage. Additionally, AnxA6 increased oxalate adhesion to RTECs by binding to oxalate. In conclusion, AnxA6 contributes to CaOx kidney stone formation by promoting both oxidative stress via calcium release and crystal-cell adhesion by binding to oxalate. This study offers new insight into CaOx kidney stone formation.

Expression profiles of urine exosomal tRNA-derived small RNAs and their potential roles in calcium oxalate stone disease.

Background and objective: Exosomes have been confirmed to be implicated in the pathogenesis of calcium oxalate (CaOx) stones. tRNA-derived small RNAs (tsRNAs) are among the oldest small RNAs involved in exosome-mediated intercellular communication, yet their role in kidney stones remains unexplored. This pilot study aimed to identify differentially expressed tsRNAs (DEtsRNAs) in urine exosomes between CaOx stone patients and healthy controls and explore their potential roles in nephrolithiasis. Method: First-morning urine samples were collected from three CaOx stone patients and three healthy controls. Urinary exosomes were isolated and analyzed by high-throughput sequencing to generate the expression profiles of tsRNAs and detect DEtsRNAs. Predicted target genes of DEtsRNAs were subjected to functional enrichment analysis. The authors also combined the public dataset GSE73680 to investigate how DEtsRNAs were related to stone formation. Results: Four DEtsRNAs were significantly upregulated in CaOx stone patients compared to healthy controls. tRF-Lys-TTT-5005c was the most elevated, followed by tRF-Lys-CTT-5006c, tRF-Ala-AGC-5017b, and tRF-Gly-CCC-5004b. Bioinformatics analysis indicated that these four types of DEtsRNAs might serve distinct biological functions. Combined with data mining from the public dataset GSE73680, the authors assumed that exosomes carrying tRF-Lys-TTT-5005c and tRF-Lys-CTT-5006c could inhibit the expression of SMAD6, FBN1, and FZD1, thereby activating the BMP signaling pathway, which might induce an osteogenic-like transformation in target cells, resulting in the formation of Randall's plaques and CaOx stones. Conclusion: The authors' findings shed light on the potential roles of tsRNAs in the pathogenesis of CaOx stone disease, highlighting exosomal DEtsRNAs as promising diagnostic biomarkers and therapeutic targets in nephrolithiasis.

Tensile Properties of Cattail Fibres at Various Phenological Development Stages.

Cattails (Typha latifolia L.) are naturally occurring aquatic macrophytes with significant industrial potential because of their abundance, high-quality fibers, and high fiber yields. This study is the first attempt to investigate how phenological development and plant maturity impact the quality of cattail fibers as they relate to composite applications. It was observed that fibers from all five growth stages exhibited a Weibull shape parameter greater than 1.0, with a goodness-of-fit exceeding 0.8. These calculations were performed using both the Least Square Regression (LSR) and Maximum Likelihood Estimation (MLE) methods. Among the estimators, the MLE method provided the most conservative estimation of Weibull parameters. Based on the Weibull parameters obtained with all estimators, cattail fibers from all five growth stages appear suitable for composite applications. The consistency of shape parameters across all five growth stages can be attributed to the morphological and molecular developments of cattail fiber during the vegetative period. These developments were confirmed through the presence of calcium oxalate (CaOx) plates, elemental composition, and specific infrared peaks at 2360 cm-1 contributing to the strength, cellulose peaks at 1635 cm-1, 2920 cm-1, and 3430 cm-1. In conclusion, it was found that the mechanical properties of cattail fiber remain similar when harvested multiple times in a single growing season.

Pharmacotherapy for patients with calcium oxalate stones and abnormal urine chemistry: A systematic review and meta-analysis for the Japanese Clinical Practice Guidelines for the Management of Urinary Stones, Third Edition.

We performed a systematic review and meta-analysis to evaluate the benefits and harms of pharmacotherapies for patients with calcium oxalate stones and abnormal urine chemistry. This article is a modified and detailed version of the commentary on Clinical Question 10 described in the Japanese Clinical Practice Guidelines for the Management of Urinary Stones, Third Edition. PubMed and Ichushi Web were searched through August 2020 for articles on pharmacotherapies for calcium oxalate stones (thiazides, citrate preparations, uric acid production inhibitors, and magnesium preparations). Two reviewers independently selected randomized controlled trials reporting reduction of stone recurrence and adverse drug reactions as outcomes and performed data extraction and quality assessment. Meta-analyses with random effects models and rating of the strength of evidence were performed. Pharmacotherapies were shown to significantly reduce stone recurrence (risk ratio 0.47, 95% confidence interval 0.35-0.63). Meanwhile, the pharmacotherapies increased adverse drug reactions leading to study dropout (risk ratio 2.51, 95% confidence interval 1.09-5.75) and adverse drug reactions/adverse events (risk ratio 1.95, 95% confidence interval 1.07-3.56). The reported adverse drug reactions were, however, mainly minor and did not frequently require discontinuation of medication (2%-16%). The strengths of evidence for both outcomes were rated as moderate, because the risk of bias, indirectness, inconsistency, imprecision, and publication bias were all serious except for one item. The overall strength of evidence across outcomes was therefore determined to be moderate. These results support the conditional recommendation to initiate pharmacotherapies for patients with calcium oxalate stones and abnormal urine chemistry.

Recurrent calcium oxalate calculi: the culprit in disguise.

Congenital sucrase isomaltase deficiency (CSID) is a rare autosomal recessive monogenic disorder of small intestinal malabsorption and manifests typically in early childhood with chronic osmotic diarrhoea. Though there have been case reports in adults presenting with hypercalcemia and renal calculi in CSID, this is quite rare in children. We hereby report a 6-year-old boy who presented with recurrent episodes of calcium oxalate calculi without any gastrointestinal symptoms and was confirmed as having sucrase isomaltase deficiency by genetic analysis.

The Involvement of Endoplasmic Reticulum Stress during the Interaction between Calcium Oxalate Crystals and Renal Tubular Epithelial Cells.

Our study aimed to elucidate the mechanisms behind the interaction between calcium oxalate (CaOx) crystals and renal tubular epithelial cells through transcriptome sequencing analysis. HK-2 cells were stimulated with or without CaOx monohydrate crystals and subjected to RNA-seq to assess the effects of CaOx crystals on gene expression changes, key pathways, and molecular players during this interaction. A total of 629 differentially expressed genes (DEGs) were identified between the control group and experimental group, with 491 genes up-regulated and 138 down-regulated. Functional enrichment analysis indicated that the DEGs were significantly associated with endoplasmic reticulum stress (ERS) and unfolded protein response. To validate our findings, we compared our results with the public dataset GSE73680 and confirmed the increased expression of two ERS-related DEGs, CHAC1 and FGF21, in renal papillary tissues from patients with CaOx stones. Collectively, these findings suggest that ERS plays a crucial role in the crystal-cell interaction and highlight the potential for developing therapeutic strategies aimed at reducing CaOx stone formation by targeting ERS-related molecules and pathways.

The Altered Proteomic Landscape in Renal Tubular Epithelial Cells under High Oxalate Stimulation.

Our study aimed to apply a proteomic approach to investigate the molecular mechanisms underlying the effects of oxalate on rat renal tubular epithelial cells. NRK-52E cells were treated with or without oxalate and subjected to quantitative proteomics to identify key proteins and key pathological changes under high oxalate stimulation. A total of 268 differentially expressed proteins (DEPs) between oxalate-treated and control groups were identified, with 132 up-regulated and 136 down-regulated proteins. Functional enrichment analysis revealed that DEPs are associated with oxidative stress, apoptosis, ferroptosis, pro-inflammatory cytokines, vitamin D, and biomineralization. SPP1, MFGE8, ANKS1A, and NAP1L1 were up-regulated in the oxalate-treated cells and the hyperoxaluric stone-forming rats, while SUB1, RNPS1, and DGLUCY were down-regulated in both cases. This altered proteomic landscape sheds light on the pathological processes involved in oxalate-induced renal damage and identifies potential biomarkers and therapeutic targets to mitigate the effects of hyperoxaluria and reduce the risk of CaOx stone formation.

Metabolomic Changes Associated with AGXT2 Genotype Variants and Stone Formation in a Colony of Cats.

OBJECTIVE: The objective of this study was to assess serum chemistries and metabolomic parameters in cats with genetic variants of the alanine-glyoxylate aminotransferase 2 (AGXT2) gene to determine abnormalities associated with urolith formation and better understand effective approaches for the treatment of cats with uroliths. METHODS: AGXT2 genotypes of 445 cats in the colony at Hill's Pet Nutrition, Inc. (Topeka, KS, USA) were assessed in a genome-wide association study. Additionally, the serum chemistries and metabolic profiles of each cat were determined, along with their lifetime history of stone incidence. Factor analysis was used as a data-reduction method for metabolites in order to perform statistical hypothesis testing and to select significant metabolites from the more than 600 serum metabolites identified. RESULTS: Of the 82 cats forming stones in the colony (18.4%), the majority were calcium oxalate. Results showed that approximately one third of the cats with the AA variant of the AGXT2 gene have stones, that chronic kidney disease (CKD) is more common in cats with stones, and that having stones results in a shorter lifespan. A discriminant variable selection process was performed to determine the complete blood count, serum biochemistries, and serum metabolomic factors that best discriminated among the three genotypes (AA, AG, GG) and between cats forming stones and non-stone formers. Several of the highly ranked discriminating factors included metabolites related to decreased aminotransferase activity in cats with the AA variant of the AGXT2 gene. Another factor that ranked highly for discriminating between stone formers and non-stone formers contained lipid metabolites, consisting of multiple sphingomyelin species and cholesterol. CONCLUSIONS: These findings support the results of feeding studies in cats, whereby CKD cats fed food supplemented with betaine and prebiotics have experienced an increase in total body mass, reduced uremic toxins, and altered sphingomyelin concentrations.

Pectolinarigenin alleviates calcium oxalate-induced renal inflammation and oxidative stress by binding to HIF-1α.

Calcium oxalate (CaOx) crystals are the main constituents of renal crystals in humans and induce tubular lumen damage in renal tubules, leading to renal calcium deposition and kidney stone formation. Oxidative stress and inflammation play important roles in regulating calcium oxalate-induced injury. Here, we evaluated the efficacy in inhibiting oxidation and inflammation of pectinolinarigenin, a biologically active natural metabolite, in CaOx nephrocalcinosis and further explored its targets of action. First, we developed cellular and mouse models of calcium oxalate renal nephrocalcinosis and identified the onset of oxidative stress and inflammation according to experimental data. We found that pectolinarigenin inhibited this onset while reducing renal crystal deposition. Network pharmacology was subsequently utilized to screen for hypoxia-inducible factor-1α (HIF-1α), a regulator involved in the body's release and over-oxidation of inflammatory factors. Finally, molecular docking, cellular thermal shift assay, and other experiments to detect HIF-1α expression showed that pectolinarigenin directly combined with HIF-1α and prevented downstream reactive oxygen species activation and release. Our results indicate that pectolinarigenin can target and inhibit HIF-1α-mediated inflammatory responses and oxidative stress damage and be a novel drug for CaOx nephrocalcinosis treatment.

S100A9 promotes renal calcium oxalate stone formation via activating the TLR4-p38/MAPK-LCN2 signaling pathway.

OBJECTIVES: To explore the role of S100A9 protein in renal calcium oxalate (CaOx) stone formation. METHODS: CaOx nephrocalcinosis mice were established via intraperitoneal injection of glyoxylate. They were treated with S100A9 deficiency, Paquinimod, or p38 MAPK-IN-1. Vonkossa staining was conducted to observe the deposition of CaOx crystals. Renal expression of inflammation, macrophage polarization, and injury markers was detected using immunohistochemistry and qPCR. Effects of S100A9 on renal tubular epithelial cells (HK-2) were explored by transcriptome sequencing. The mechanism of how S100A9 regulated lipocalin 2 (LCN2) was studied through Western Blot. Flow cytometry was performed to detect the influence of LCN2 on macrophages polarization. RESULTS: S100A9 deficiency inhibited the renal deposition of CaOx crystals in nephrocalcinosis mice. S100A9 upregulated the expression of LCN2 in HK-2 cells via activating the TLR4-p38/MAPK pathway. LCN2 promoted the migration and M1 polarization of macrophages. S100A9 deficiency downregulated the renal expression of LCN2, IL1-ß, Kim-1, F4/80, and CD80 in nephrocalcinosis mice. Paquinimod and p38 MAPK-IN-1 both inhibited the renal deposition of CaOx crystals and downregulated the expression of LCN2, IL1-ß, Kim-1, F4/80, iNOS, and CD68 in nephrocalcinosis mice. CONCLUSIONS: S100A9 promotes renal inflammatory injury by activating the TLR4-p38/MAPK-LCN2 pathway and then contributes to CaOx stone formation.

Quercus dentata Thunb. leaves extract inhibits CaOx crystallization and ameliorates ethylene glycol-induced CaOx kidney stones via the OPN/CD44 and NLRP3 pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Quercus dentata Thunb. (QD), a member of the Fagaceae family and genus Quercus, with distributions in China, Japan, Korea, and other regions. As recorded in the Ben Cao Gang Mu (Compendium of Materia Medica) and other classical Chinese medical texts, QD has been traditionally employed in Traditional Chinese Medicine (TCM) for their hemostatic and diuretic effects and has been used to treat urinary stones (Lin Zheng). It is also the main ingredient of the Mishitong capsule (MST), a Chinese patent drug, used for kidney stones and ureteral stones. Nonetheless, the specific active ingredients and the mechanisms of QD in treating kidney stones remain to be elucidated, which is crucial for advancing the scientific understanding and clinical application of this traditional medicine. AIM OF STUDY: This study aimed to identify the active constituents of QD water extract (QDWE), explore its inhibitory effects on kidney stones through in vitro and in vivo studies, and elucidate the underlying mechanisms of the OPN/CD44 axis and the NLRP3 signaling pathway to provide a full understanding of its potential as a novel treatment approach against kidney stones. MATERIALS AND METHODS: The micromolecular components in the supernatant of QDWE (QDS) were analyzed by UPLC-Q-Exactive-Orbitrap-MS and the monosaccharide composition of the macromolecular polysaccharide components in the crude polysaccharide (QDP) was determined by pre-column derivatization in HPLC. The effects of QDWE, QDS and QDP on the shape, size, and structure of calcium oxalate (CaOx) crystals in vitro were explored by XRD, FTIR and SEM. The effects of QDWE, QDS and QDP on CaOx kidney stones in SD rats induced by ethylene glycol and VD3 were compared in vivo. Furthermore, the underlying mechanisms of OPN/CD44 and NLRP3 pathways were investigated by Western blot analysis. RESULTS: There were 32 compounds identified in QDS. The monosaccharide composition ratio of QDP was Man: L-Rha: D-GlcA: D-GalA: D-Glc: D-Gal: L-Ara = 1.01: 22.52: 8.27: 38.61: 3.43: 17.80: 6.38, indicating a mixture of pectin-type acidic heteropolysaccharides. QDP had a more significant inhibitory effect on CaOx crystals in vitro than QDWE, which can inhibit the formation of CaOx monohydrate crystals (COM) and convert them into thermodynamically unstable CaOx dihydrate (COD) crystals. The high dose of QDWE exhibited significant in vivo efficacy (P < 0.05), including anti-calculus, diuretic effects, and kidney protection, marked by decreased calcification and stone formation, alongside improved kidney vitality. Furthermore, the protective effects of QDWE were demonstrated to be associated with the OPN/CD44 and NLRP3 pathways. CONCLUSION: The studies identified and analyzed the active constituents of QDWE. Among these, QDP significantly inhibited CaOx crystal generation in vitro and could be a potential component for the treatment of urinary stones in QDWE. Moreover, the results indicated that QDWE had a remarkable therapeutic effect on CaOx stones by modulating the OPN/CD44 axis to affect stone formation and the NLRP3 signaling pathway to mediate inflammation, providing an experimental basis for the mechanism of anti-urinary stone and deep development of QD.

Chronic Kidney Disease and Kidney Stone in a Wild Chimpanzee (Pan troglodytes verus) in Côte d'Ivoire.

An older wild female chimpanzee (Pan troglodytes) was found dead with a large calcium oxalate stone in the renal pelvis. Histopathological changes included glomerulosclerosis, interstitial nephritis and fibrosis, focal mineralization, and medial hypertrophy. Urinary albumin-creatinine-ratio showed increased values from 15 months before death. Causes of the kidney disease remain unconfirmed.

The Elephant in the Room: Clinical Progression and Management of Elephant Ear Plant Toxicity in an Adult.

Elephant ear plants are popular ornamental plants renowned for their large foliage. These plants have been implicated in various inadvertent and deliberate ingestions. The leaves and roots of these plants contain raphides, which are needle-shaped calcium oxalate crystals. Ingestion of these crystals results in a localized inflammatory response, typically manifesting as irritation, edema, hypersalivation, and dysphagia. Herein, we describe a case of an older gentleman who presented to our institution following intentional ingestion of the leaves and roots of an elephant ear plant. This report describes the clinical manifestations secondary to the toxicities related to the ingestion of this plant and displays the successful conservative management approach employed following multiple diagnostic studies.

Comparison of cat stone matrix and cat urine proteomes to human calcium oxalate stone matrix and urine proteomes.

Cat calcium oxalate monohydrate kidney stone matrix proteome showed great similarity to human calcium oxalate monohydrate stone matrix proteome, but inference of mechanistic similarity was limited by the absence of cat urine proteomic data. In this study, urine proteome distributions were measured by the same methods in 7 healthy cats for comparison to both the published human urine and cat calcium oxalate stone matrix proteomes to assess for similar enrichment patterns in both species. Furthermore, proteomic distributions were determined in cat struvite stone matrix to test for similarity to calcium oxalate monohydrate stone matrix and urine proteomes. Cat urine proteins demonstrated a similar distribution of abundance as a function of isoelectric points or net charge to human urine samples, and consequently the similarly altered patterns of protein distributions seen in calcium oxalate monohydrate stone matrix seen from both cat and human stones likely derives from the same preferential adsorption mechanism. Furthermore, the fact that protein abundance patterns seen in cat struvite stone matrix samples differ from both urine and calcium oxalate monohydrate stone matrix proteomes in systematic ways suggests that a combination of protein-protein and protein crystal interactions underly the formation of the crystal aggregates that comprise stones.

Metabolomics analysis reveals a protective effect of hydroxycitric acid on calcium oxalate-induced kidney injury.

Objectives: Prior research has indicated that hydroxycitric acid (HCA) can impede the formation of calcium oxalate (CaOx) crystals, yet the specific mechanisms underlying its therapeutic effects remain unclear. In this study, we delved into the protective effects of HCA against glyoxylate-induced renal stones in rats and sought to elucidate the underlying metabolic pathways. Materials and Methods: Forty rats were randomly assigned to five groups: control group, model group, L-HCA-treated group, M-HCA-treated group, and H-HCA-treated group. Von Kossa staining was conducted on renal sections, and blood urea nitrogen and serum creatinine were determined by biochemical analysis. Meanwhile, body weight and urine volume were also measured. We subjected urine samples from the rats to analysis using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Next, we employed a metabolomic approach to scrutinize the metabolic profiles of each group. Results: HCA significantly reduced blood urea nitrogen and serum creatinine, and increased body weight and urine volume. It also reduced CaOx crystal deposition. A total of 24 metabolites, exhibiting a significant reversal pattern following HCA administration, were identified as urine biomarkers indicative of HCA's preventive effects against CaOx crystal-induced renal injury. These metabolites are primarily associated with glycine, serine, and threonine metabolism; phenylalanine metabolism; tricarboxylic acid cycle; taurine and hypotaurine metabolism; and tryptophan metabolism. Conclusion: It was demonstrated that HCA has a protective effect against CaOx crystal-induced kidney injury in rats by modulating various metabolic pathways. Additionally, results suggest that HCA holds promise as a potential clinical therapeutic drug for both the prevention and treatment of renal stones.

Morin hydrate mitigates calcium oxalate urolithiasis by inhibiting oxalate synthesis and modulating crystal formation.

Calcium oxalate (CaOx) urolithiasis is a prevalent urinary disorder with significant clinical impact. This study investigates the therapeutic potential of Morin Hydrate (MH), a natural bioflavonoid, in preventing CaOx stone formation. Molecular docking studies revealed that MH binds strongly to glycolate oxidase (GO), suggesting its inhibitory effect on oxalate synthesis. In vitro assays demonstrated that MH effectively inhibits CaOx crystal nucleation, aggregation, and growth, altering crystal morphology to less stable forms. Diuretic activity studies in Wistar rats showed that MH substantially increased urine volume and ion excretion, indicating its moderate diuretic effect. In vivo experiments further supported these findings, with MH treatment improving urinary and serum markers, reducing oxidative stress, and protecting renal tissue, as evidenced by histopathological analysis. Notably, MH administration significantly decreased GO and lactate dehydrogenase activities in urolithiatic rats, indicating a reduction in oxalate production. These results suggest that MH is a promising candidate for the prevention and treatment of CaOx urolithiasis, with the potential for clinical application in reducing the risk and recurrence of kidney stones.

Research on key pathogenesis and potential intervention targets of idiopathic renal calculi composed of calcium oxalate (CaOx) based on bioinformatics.

Background: Calcium oxalate (CaOx) kidney stones are the most common type of stones in the urinary system, and their formation involves a complex mechanism with multiple contributing factors. In recent years, with the development of bioinformatics, there has been a deeper understanding of the pathogenesis of this type of disease. This study aimed to analyze the gene expression profiles of idiopathic kidney stones composed of CaOx using bioinformatics methods. By investigating the pathogenesis at the molecular level and identifying potential therapeutic targets, the study also integrated clinical data to validate the clinical relevance of the target genes. Methods: Gene expression profiles from the GSE73680 dataset were analyzed via the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs) between Randall's plaques (RPs) from kidney papillae associated with CaOx stones and normal kidney papillae tissues. The Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database was employed to construct transcription factor (TF)-DEG-microRNA (miRNA) networks, and key genes were screened using the Molecular Complex Detection (MCODE) plugin. A gene set enrichment analysis (GSEA) was performed to investigate the possible underlying mechanisms of the key genes. The clinical data of idiopathic CaOx kidney stone patients who received treatment at the General Hospital of Northern Theater Command from January 2020 to December 2022 were retrospectively analyzed. Enzyme-linked immunosorbent assay (ELISA) kits were used to measure the transcriptional activity of the key genes in calcified kidney papillae tissues. Univariate and multivariate logistic regression analyses were employed to analyze the transcriptional activity of the key genes and their association with idiopathic kidney stones composed of CaOx. Results: In the GSE73680 dataset, 276 upregulated and 538 downregulated DEGs were identified. Protein-protein interaction network construction revealed one significant module and three candidate genes [interleukin 11 (IL-11), interleukin 16 (IL-16), and interleukin 32 (IL-32)]. The TF-DEG-miRNA network indicated that IL-11 might be regulated by 25 TFs and interact with six miRNAs. The GSEA suggested that IL-11 could influence the development of idiopathic CaOx stones through chemokine expression and via the signaling pathways of the nucleotide-binding oligomerization domain-like receptors [NOD-like receptors (NLRs)] and toll-like receptors (TLRs). The clinical data analysis revealed that the IL-11 serum levels were significantly elevated in the patients with idiopathic kidney stones composed of CaOx compared to the control subjects (P<0.001). Additionally, IL-11 was identified as an independent risk factor for the development of idiopathic CaOx kidney stones (P<0.001). Conclusions: The bioinformatically identified key genes and signaling pathways provide a deeper understanding of the potential mechanisms underlying idiopathic CaOx kidney stones. Preliminary clinical trials suggest that elevated serum IL-11 levels in idiopathic CaOx kidney stone patients could serve as a possible diagnostic biomarker and treatment target.

Two distinct phenotypes of calcium oxalate stone formers could imply different long-term risks for renal function.

Endoscopic and biopsy findings have identified two distinct phenotypes among individuals with calcium oxalate (CaOx) kidney stones. One phenotype exhibits normal renal papillae but shows interstitial mineral deposition, known as Randall's plaque. The other phenotype presents with collecting duct plugging and a higher incidence of loss of papilla tissue mass. With Randall's plaque, renal papilla injury involves the loss of small patches of calcified tissue (Randall's plaque detaching with the stone), which likely results in damage to only a few nephrons. In contrast, collecting duct mineral plugs are very large, causing obstruction to tubular flow. Since each terminal collecting duct drains thousands of nephrons, ductal plugs could lead to the degeneration of many nephrons and a significant loss of renal glomeruli. New visualization techniques for immune cells in papillary biopsies have revealed that the Randall's plaque phenotype is marked by the accumulation of macrophages around the plaque regions. In contrast, preliminary data on the plugging phenotype shows collecting duct damage with mineral plugs, increased T-lymphocytes throughout the papilla, and tubulitis, characterized by T-cell infiltration into nearby collecting duct epithelium. This suggests that while some CaOx stone formers may have some papillary inflammation but with minimal damage to nephrons, others suffer from obstruction to flow for many nephrons that may also include destructive inflammation in the renal tissue. We propose that the long-term risks for loss of renal function will be greater for CaOx stone formers with the plugging phenotype.

Expression Profiles of Claudin Gene Family Members in Patients With Recurrent Calcium Oxalate Kidney Stones.

INTRODUCTION: In this study, we aimed to evaluate and compare the expression profiles of CLDN gene family members responsible for the mechanism of stone formation in patients with recurrent calcium oxalate stones and in a control group without a history of renal stones. METHODS: Nineteen patients with recurrent calcium oxalate renal calculi who underwent percutaneous nephrolithotomy and 21 control patients without renal calculi who underwent surgery for other reasons were included in the study. The urinary calcium, oxalate, and citrate levels of the patients included in the study, as well as those in the control group, were within normal ranges. They did not have proteinuria in their urine. The biochemical parameters were also within normal limits. Biopsy samples taken from the intact renal cortex parenchymal tissue were consistent. Total RNA was isolated from biopsy samples and expression profiles of target genes (Claudin 1-4, 7, 8, 10, 14, 16, 18, 19) were determined by real-time polymerase chain reaction (PCR). RESULTS: It was determined that CLDN1 gene expression in patients with recurrent calcium oxalate kidney stones was approximately four times higher than in the control group; this difference was statistically significant (p<0.050). CLDN1 expression was also strongly positively correlated with CLDN4 (r=0.642), CLDN7 (r=0.753) and CLDN14 (r=0.651) Conclusions: We thought that CLDN1 overexpression might play a role in the pathogenesis of recurrent calcium oxalate stone formation. CLDN1 together with CLDN2, CLDN4, CLDN7, and CLDN14 are also probably responsible for this pathogenesis.