Stone Formation Research Articles

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.

Nineteen-year forgotten ureteral stent removed under local anaesthetic from a transplanted kidney.

Following renal transplant, ureteral stents aim to minimise ureteroneocystostomy anastomotic complications. Although there is no specified timing for stent removal after transplantation, these are ideally removed at between 2 and 4 weeks. However, forgotten stents can adversely affect renal allograft function and contribute to obstructive uropathy. We present a 59-year-old man with a retained ureteral stent for more than 19 years with an absence of encrustations, fragmentation, migration and stone formation. To our knowledge, this is the longest retained ureteral stent in a renal transplant patient and the first forgotten stent removed via flexible cystoscopy under local anaesthetic.

Oxaluria in inflammatory bowel diseases (review)

AIM: to analyse and synthesize Russian and foreign literature, to get acquainted with the concept of oxaluria, its types, transport mechanisms of oxalate transport in the intestine and the relationship between hyperoxaluria and inflammatory bowel diseases in order to identify possible options for therapeutic action on the mechanisms of development of these pathologies. MATERIALS AND METHODS: the literature review was based on the Internet data, including bibliographic directories, books, journals, and original articles. The literature sources used for the article reflect the essence of the described problem to the fullest extent possible and can be useful for both practicing physicians and students of medical universities. RESULTS: the gastrointestinal tract through epithelial transport of oxalate plays an exclusive role in oxalate homeostasis and hyperoxaluria. Metabolism of dietary oxalate and the formation of endogenous oxalate, its secretion, absorption, transport and biodegradation by intestinal microflora may influence the excretion of this compound by the kidneys. Knowledge of the interrelated relationships of the gut-kidney axis, mechanisms of transport, transport and biodegradation of oxalate, especially in inflammatory bowel disease, is of great importance for understanding the pathophysiology of hyperoxaluria as a risk factor for urinary stone formation with a point of pharmacological action in the gut. This literature review introduces the concept and forms of oxaluria, shows the classification of oxaluria, describes each form, and broadly explains the metabolism and mechanisms of oxalate transport in the human body. Special attention is given to intestinal hyperoxaluria and anion exchangers belonging to the large multifunctional SLC26 gene family, most of which are expressed throughout the gastrointestinal tract. The authors emphasise their current role in intestinal oxalate transport, as well as methods of possible drug action on the mechanisms of hyperoxaluria. CONCLUSION: a multidisciplinary approach is needed to address the problems of intestinal hyperoxaluria and, consequently, the treatment of urolithiasis. The role of newly identified intestinal and renal anion exchangers is not fully understood, hence the targets and mechanisms of action on these types of exchangers with the possibility of preventing the development of urolithiasis are not fully understood. Further randomised studies on the problem under investigation are needed.

Urinary Stone Formation and Testosterone Supplementation: Insights from a Cross-sectional Study in Athletes

Introduction: The use of exogenous testosterone has become increasingly prevalent in sports fields, raising concerns about its potential risks and benefits. Methods & Materials: This study aimed to investigate the effects of testosterone supplementation on stone formation in the urinary tract and urine composition. A total of 1080 athletes participated in a two-year cross-sectional study, with 495 individuals receiving testosterone supplementation and 585 individuals serving as non-users. Blood and urine samples were collected, and CT scans were performed to assess stone presence. Results: The results revealed a significant increase in crystalluria among testosterone users compared to non-users (38.2% vs. 2.7%, p=0.004). Imaging findings also showed a higher incidence of abnormal results in testosterone users (25.2% vs. 4.3%, p=0.0017), with kidney calcification, pelvic and calyceal stones, ureteral stones, and bladder stones observed. Conclusion: However, further metabolic studies are required to establish a definitive cause-and-effect relationship between testosterone use and stone formation. This study sheds light on the potential risks associated with exogenous testosterone use and highlights the need for evidence-based recommendations in sports and athletic performance.

Unraveling the role of gut microbiota by fecal microbiota transplantation in rat model of kidney stone disease

Emerging research on the microbiome highlights the significant role of gut health in the development of kidney stones, indicating that an imbalance in gut bacteria or dysbiosis can influence the formation of stones by altering oxalate metabolism and urinary metabolite profiles. In particular, the overabundance of specific bacteria such as Enterococcus and Oxalobacter spp., which are known to affect oxalate absorption, is observed in patients with urolithiasis. This study investigates the effects of gut dysbiosis on urolithiasis through fecal microbiota transplantation (FMT) from patients to rats and its impact on urinary mineral excretion and stone formation. Fecal samples from eight patients with calcium oxalate stones and ten healthy volunteers were collected to assess the gut microbiome. These samples were then transplanted to antibiotic-pretreated Wistar rats for a duration of four weeks. After transplantation, we evaluated changes in the fecal gut microbiome profile, urinary mineral excretion rates, and expression levels of intestinal zonula occluden-1 (ZO-1), SLC26A6 and renal NF-κB. In humans, patients with urolithiasis exhibited increased urinary calcium and oxalate levels, along with decreased citrate excretion and increased urinary supersaturation index. The fecal microbiota showed a notable abundance of Bacteroidota. In rodents, urolithiasis-FMT rats showed urinary disturbances similar to patients, including elevated pH, oxalate level, and supersaturation index, despite negative renal pathology. In addition, a slight elevation in the expression of renal NF-κB, a significant intestinal SLC26A6, and a reduction in ZO-1 expression were observed. The gut microbiome of urolithiasis-FMT rats showed an increased abundance of Bacteroidota, particularly Muribaculaceae, compared to their healthy FMT counterparts. In conclusion, the consistent overabundance of Bacteroidota in both urolithiasis patients and urolithiasis-FMT rats is related to altered intestinal barrier function, hyperoxaluria, and renal inflammation. These findings suggest that gut dysbiosis, characterized by an overgrowth of Bacteroidota, plays a crucial role in the pathogenesis of calcium oxalate urolithiasis, underscoring the potential of targeting the gut microbiota as a therapeutic strategy.

SIALOLITHIASIS: REVIEW

Objectives. Sialolithiasis is the most common obstructive salivary gland disease, responsible for approximately 50% of salivary glands pathology cases. The aim of this study is to provide the literature review to present the incident rate, etiology, diagnostic and treatment trends of sialolithiasis Materials and methods: Data from the Medline database, PubMed.gov and supplementary sources were used to conduct a systematic literature search. Results: The 116 studies were analyzed. The relevant data were exported, summarized and presented. Conclusion: The most of available studies regarding the incidence rate of sialolithiasis have been based on selected hospital data and there are a few multicenter analyses. The etiology of salivary stones formation remains not completely clear and various hypotheses have been put forward, thus research into etiologic factors is still continues. Despite the introduction of new technologies in the diagnostics of salivary gland, the routine methods like radiographs and ultrasound examination are still relevant and widely used. Gland preserving techniques in the treatment of sialolithiasis have continuously replaced radical surgery

Causality between ankylosing spondylitis and urolithiasis in European Populations: A Mendelian randomization analysis

BackgroundAnkylosing spondylitis (AS) is an inflammatory condition affecting the spine. Observational studies have suggested a heightened risk of urolithiasis in AS patients. However, due to the inherent limitations of observational research, the causal relationship between the two remains to be determined. ObjectiveUtilizing the Mendelian randomization analysis approach, this study sought to explore the causal link between AS and urolithiasis. MethodsData from genome-wide association studies were employed for analysis. Mendelian randomization analyses were conducted using the IVW, MR-Egger, Weighted Median, and Weighted Mode methods. Heterogeneity tests, sensitivity analyses, and pleiotropy analyses were also performed. ResultsThe causality between AS and urolithiasis was supported by the IVW (P=.02), Weighted Median (P=.006), and Weighted Mode (P=.01) methods. The MR-Egger method (P=.07) did not support this causal relationship, yet its directionality was consistent with the other three methods. None of the four analysis methods supported a reverse causal relationship between AS and urolithiasis. ConclusionOur study demonstrates a causal relationship between AS and urolithiasis, with no evidence of reverse causality. Given the increased risk of urolithiasis in AS patients, it is crucial to implement preventive strategies and early detection. Stone composition analysis should also be incorporated into clinical practice for these patients, as it can provide essential insights into the metabolic and genetic factors contributing to stone formation, thus improving diagnostic accuracy and treatment outcomes. Future studies are needed to further validate these findings and explore the detailed mechanisms involved.

Changes in 24-hour Urine Chemistry in Patients with Nephrolithiasis during Weight Loss with Glucagon-Like Peptide-1 Based Therapies

Background: Obesity is an independent risk factor for incident and recurrent nephrolithiasis. The impact of weight loss through glucagon-like peptide 1 (GLP-1) receptor agonists and dual GLP-1/ gastric inhibitory polypeptide receptor agonists (GLP-based therapies) on nephrolithiasis is not well-understood. This study examined the changes in 24-hour urine chemistry assessing for stone risk during weight loss through GLP-based therapies. Methods: This retrospective analysis identified adult stone formers followed at our academic institution’s weight wellness clinic between September 2015 and August 2023 and included patients with at least two 24-hour urine collections for stone risk assessment. 24-hour urine parameters before and during weight loss in patients on GLP-based therapies were compared. Results: Forty-four obese patients with nephrolithiasis experienced significant weight reduction (-6.6±7.3 kg, p<0.001) over a median 1.1 years of follow-up with GLP-based therapies. During this period, there was a significant decrease in 24-hour urine oxalate (40±16 to 32±11 mg/day, p=0.002), sulfate (21±10 to 17±9 mmol/day, p=0005), and ammonium (35±22 to 29±15 mEq/day, p=0.01). There were non-significant changes in urine calcium, citrate, uric acid, pH, phosphorus, sodium, potassium, magnesium, chloride, creatinine or total volume. Additionally, there was no statistical difference in urine supersaturation indices with respect to calcium oxalate, calcium phosphate and uric acid. Conclusion: Our results indicate that weight loss through GLP-based therapies is not associated with pro-lithogenic changes in 24-hour urine chemistry in patients with nephrolithiasis, unlike what happens with other weight loss modalities.

Ab Initio Molecular Dynamics Simulations of Phosphocholine Interactions with a Calcium Oxalate Dihydrate (110) Surface.

We use ab initio modeling (CASTEP) to help elucidate the crystallization phenomena and chemistry behind kidney stone composition and formation. To explore the stone formation process, we have constructed a surface model of calcium oxalate dihydrate-the mineral most commonly found in patients with hypercalciuria and modeled stone growth, by simulating further calcium oxalate adsorption onto the surface (-7.446 eV, -0.065 eV/atom). Furthermore, urine analysis of kidney stone patients has previously revealed that their urine contains higher concentrations of phospholipids compared to healthy individuals. Therefore, to investigate the interactions between urinary macromolecules and the growing crystal surfaces at an atomic level, we have performed ab initio molecular dynamics simulations of phosphocholine adsorption on calcium oxalate surfaces. We have shown that the phosphocholine headgroups become entrapped within the growing crystal and the lowest energy structures (-18.008 eV, -0.0396 eV/atom) are those where the calcium oxalate dihydrate surfaces have become disrupted, with reorganization of their crystallographic structure. Urinary calculi (kidney stones) are a common ailment affecting around 10% of the world's population and resulting in nearly 90,000 finished consultant episodes (FCE) each year in the United Kingdom [Hospital Episode Statistics, Admitted Patient Care-England, 2011-12 NHS Digital, 2021-2022. https://digital.nhs.uk/data-and-information/publications/statistical/hospital-admitted-patient-care-activity/hospital-episode-statistics-admitted-patient-care-england-2011-12].

The Role of Diet in Kidney Stone Formation: A Comprehensive Narrative Review

The Role of Diet in Kidney Stone Formation: A Comprehensive Narrative Review

Implementation of Extreme Learning Machine Method with Particle Swarm Optimization to Classify of Chronic Kidney Disease

Kidney Disease (CKD) appears as a pathological condition due to infection of the kidneys and blockages due to the formation of kidney stones. In the Indonesian context, kidney disease is the second most common disease after heart disease based on BPJS Health data. Notably, in this scenario, medical practitioners and individuals with specialized knowledge in the field are still faced with challenges in effectively classifying CKD cases, thereby making them vulnerable to erroneous diagnostic conclusions. The main objective underlying this particular research effort revolves around increasing the level of accuracy that characterizes the CKD classification process by orchestrating the incorporation of Particle Swarm Optimization (PSO) techniques into the operational framework of Extreme Learning Machines (ELM) with the aim of ensuring optimal results. Configuration of input weights and critical biases to achieve superior diagnostic results. The results obtained from the investigation process include many numerical parameters including but not limited to determining the ideal number of hidden nodes set at 11, population size 80, identification of the most preferred number of iterations denoted by the Best value of 20, aggregate inertia weight assessed at 0.5, along with the constants 1 (c1) and 2 (c2) each registering a value of 1, culminating in the achievement of an accuracy metric pegged at an impressive level of 98.50%. Consequently, the implications obtained from this empirical investigation strengthen the assertion that the use of PSO optimization strategies within the operational framework of ELM has the potential to yield major advances in the classification evaluation domain related to CKD diagnosis.

Impact of Nutrition and Exercise on Kidney Health: How to Prevent Kidney Stones?

IntroductionKidney stone disease, characterized by the formation of calculi in the kidneys, is becoming an increasingly common urinary tract disorder in developed countries. Although kidney stone disease may be caused by metabolic disorders, anatomical, functional, and genetic factors, diet plays a crucial role in its formation. Changing dietary habits has become a primary tool in the treatment and prevention of kidney stone disease. ObjectiveThe aim of this study is to present research on the impact of diet and its individual components on the risk of kidney stone formation. Special attention is given to the role of vitamins, minerals, and dietary habits in the pathogenesis and prevention of this condition. Materials and MethodsThe study involves a review of the scientific literature, considering research published in reputable medical and scientific journals regarding the impact of diet on the risk of kidney stones, focusing on key dietary components such as calcium, magnesium, sodium, vitamins C and D, as well as the role of physical activity and proper hydration. ConclusionsA balanced diet, proper hydration and maintaining a healthy body weight are fundamental elements in preventing of kidney stone disease. Adequate hydration is crucial; high fluid intake, especially water, dilutes urine and reduces the concentration of lithogenic substances.Calcium and magnesium intake are particularly important as they influence the absorption and excretion of oxalates, and excessive supplementation with vitamins C and D should be avoided. A diet rich in fruits and vegetables, and the limitation of animal protein and salt, can significantly reduce the risk of kidney stone formation. Ultimately, dietary changes and lifestyle modifications, including weight control and physical activity, play a crucial role in preventing kidney stone disease. However, further research is needed to develop effective dietary guidelines tailored to the individual needs of patients.

From computational prediction to experimental validation: Hesperidin's anti-Urolithiatic activity in sodium oxalate-induced urolithiasis models in fruit flies and mice

Kidney stones have been a long-standing health issue, contributing to renal failure, especially in co-morbid patients. There is an increasing interest in exploring natural compounds with anti-urolithiatic properties. Our study utilized in-silico techniques followed by in vivo experiments to evaluate the anti-urolithiatic potential of selected phytoconstituents. Molecular docking studies were conducted on 11 different targets, including inhibitors of kidney stone formation, antioxidant enzymes, and biomarkers of kidney injury, to explore the potential of anti-urolithiatic effects of 38 phytoconstituents from medicinal plants possessing diuretic activity. Further, the anti-urolithiatic activity of the phytoconstituent was evaluated using a sodium oxalate-induced urolithiatic fruit fly and mouse model. Hesperidin emerged as a promising candidate, exhibiting binding interactions with a specific set of 11 target proteins involved in crystal formation with minimal free energy. Hesperidin demonstrated promising anti-urolithiatic potential in mitigating urolithiasis as evidenced by reduced crystal covered area of Malpighian tubules of fruit fly and reduced blood urea nitrogen (BUN), serum creatinine and serum sodium, potassium levels in mice. Moreover, it increased urine volume, preventing crystal deposition, and reduced urine urea nitrogen, creatinine, sodium, and potassium levels, enhancing urine flow and preventing crystal accumulation. Histopathological analysis further supported its efficacy by showing minimal crystal deposition and reduced kidney damage. Hesperidin exhibited superior effectiveness in reducing various serum and urine parameters, making it promising alternatives for urolithiasis management warranting further investigation to determine its safety and optimal dosages in human.

The combination of oxalic acid and uric acid degrading probiotic from traditional Chinese fermented food reduces calcium accumulation and prevents kidney stones formation in rats

Kidney stones, often resulting from a complex interplay of factors including oxalic acid, uric acid, and calcium. Current treatments lack comprehensive consideration of these factors and come with side effects. In this study, Lactobacillus paracasei GR-10 and Pediococcus acidilactici GR-11 were isolated from the fermented food “Jiangshui”. GR-10 demonstrated the ability to degrade 62.70% of oxalic acid (10 mM) within 24 h, while GR-11 degraded 28.60% of uric acid (4 mM). Combined treatment with GR-10 and GR-11 significantly reduced the number of stones in rats with ethylene glycol-induced kidney stones. This reduction was accompanied by a 57.19% decrease in urinary oxalate and a 52.80% decrease in serum uric acid levels. Simultaneously, urinary calcium level decreased by 27.18%. Inflammatory markers and indicators of oxidative stress associated with kidney stones were restored. Furthermore, the combined treatment effectively regulated the microbiota imbalance induced by kidney stones, resulting in reduced purine nucleoside accumulation in rat feces. This study offers promising insights into probiotics as an adjunct therapy for the prevention of kidney stones in the future.

Longitudinal Incidence of Kidney/Urinary Stones in Individuals With Severe Motor and Intellectual Disabilities.

To investigate the longitudinal incidence of kidney/urinary stones in patients with severe motor and intellectual disabilities and explore health burden events in patients with stone formation. This was a retrospective, observational study. We identified patients with severe motor and intellectual disabilities who had the following: 1) admission to our hospital wards for >10 years; 2) two or more assessments for stone formation by ultrasonography or computed tomography; and 3) absence of kidney/urinary stones in the first imaging study. The Kaplan-Meier method was used to analyze the cumulative incidence of kidney/urinary stones. Recurrent urinary tract infections, hydronephrosis, renal dysfunction, and death were identified as health burdens. Among the 41 patients (19 men, 22 women; median age, 28 years; range, 8-50 years), stone formation was detected in 11 (27%) patients during the observation period. The cumulative incidence rate of stone formation was 9.8% (95% confidence interval, 3.8-23.9) and 18.7% (95% confidence interval, 9.2-35.7) at five and 10 years, respectively. Death was frequently observed in patients with stone formation; six (55%) of the 11 patients with stone formation died during the follow-up period; two (15%) died among the other 30 patients without stone formation. However, only one patient with stone formation died in a renal event; the causal relationship between the stone formation and the deaths was not clarified. The longitudinal incidence of kidney/urinary stones was higher in patients with severe motor and intellectual disabilities than in the general population. Considering the difficulty of patients with severe motor and intellectual disabilities in conveying their symptoms, regular assessment of the kidney using abdominal imaging may be recommended.

Renal transplant nephrolithiasis: Presentation, management and follow-up with control comparisons.

To analyse the presentation, management and long-term outcomes of renal transplant patients who formed kidney stones in their allograft. The secondary aim was to identify risk factors for stone formation in this cohort. Patient information from an institutional renal transplant database was used to identify individuals who both did and did not form kidney stones following renal transplantation. Computerized tomography (CT) imaging was used to make the diagnosis of kidney stones and measure stone size. Age- and gender-matched controls never forming a stone in their allograft were used for comparative analysis to identify risk factors for stone formation in transplant patients. A total of 8835 transplant patients were included in the study, of which 128 (1.4%) formed a kidney stone in their allograft after surgery. The mean time to kidney stone identification was 6.2years, and the mean number of stones formed was 1.7, with a mean maximum size dimension on a CT scan of 5.7mm per stone. A total of 26 patients were subjected to stone-removing procedures, the most common being ureteroscopy (42.3%). The primary intervention failed in eight patients requiring a secondary intervention, and percutaneous nephrolithotomy (PCNL) had the lowest success rate (60%). A total of 164 controls were identified. In comparison to controls, stone formers had lower serum calcium (p= 0.008), lower estimated glomerular filtration rates (p= 0.019), higher lymphocyte counts (p= 0.021) and greater rate of urinary tract infection (p= 0.003). Graft failure rates were the same (p= 0.524), but time to graft failure was significantly longer in stone patients compared with controls (p= 0.008). The rate of stone formation is low in transplant patients. Success rates for stone treatment vary based on the surgery selected, with PCNL being the worst. Graft survival rates were equivocal, but survival time was better in stone patients. Our analysis calls for further investigation of this important topic.

Effects of SLC34A3 or SLC34A1 variants on calcium and phosphorus homeostasis.

Variants in SLC34A1 and SLC34A2 genes, which encode co-transporters NaPi2a and NaPi2c, respectively, can lead to hypophosphatemia due to renal phosphate loss. This condition results in hypercalcitriolemia and hypercalciuria, leading to formation of kidney stones and nephrocalcinosis. Phenotype is highly variable. Management includes hyperhydration, dietary modifications, and/or phosphate supplementation. Thiazides and azoles may be used, but randomized studies are needed to confirm their clinical efficacy. We conducted a retrospective study in the pediatric nephrology unit at Grenoble University Hospital from January 2010 to December 2023. The study aimed to describe clinical and biological symptoms of patients with confirmed SLC34A1 and SLC34A3 gene variants and their outcomes. A total of 11 patients (9 females) from 6 different families had variants in the SLC34A1 (5 patients) and SLC34A3 (6 patients) genes. Median age at diagnosis was 72 [1-108] months. Average follow-up duration was 8.1 ± 4.5years. Presenting symptom was nephrocalcinosis (4 cases), followed by renal colic (3 cases). At diagnosis, 90% of patients had hypercalciuria and 45% had hypercalcitriolemia. Management included hyperhydration and dietary advice. All patients showed favorable outcomes with normal growth and school attendance. One patient with an SLC34A3 variant showed regression of nephrocalcinosis. Kidney function remained normal. Clinical and biological manifestations of SLC34 gene variants are highly variable, even among siblings; therefore, management must be personalized. Hygienic and dietary measures (such as hyperhydration, a low sodium diet, and age-appropriate calcium intake) result in favorable outcomes in most cases. Use of azoles (e.g., fluconazole) appears to be a promising therapeutic option.

Biology of calcium homeostasis regulation in intestine and kidney.

Calcium (Ca2+) is an essential divalent cation involved in many bodily functions including bone composition, cell growth and division, blood clotting, and muscle contraction. The bone, intestine, and kidneys are important to the maintenance of Ca2+ homeostasis. Ninety-nine percent of body Ca2+ is stored in the skeleton as hydroxyapatite. The small, and to a lesser extent the large intestine absorbs Ca2+ from the diet. Once in the circulation, Ca2+ is filtered by the glomerulus and the majority, >95%, is reabsorbed along the nephron. The remainder is excreted in the urine. Two general (re)absorptive pathways contribute to the vectorial transport of Ca2+ across renal and intestinal epithelia: 1) a paracellular pathway, which is reliant on claudins in the tight junction of epithelium and the electrochemical gradient and 2) a transcellular pathway, which requires different influx, intracellular buffering/shuttling and basolateral efflux mechanisms, to actively transport Ca2+ across the epithelial cell. Blood Ca2+ levels are maintained by hormones including parathyroid hormone, 1,25-dihydroxyvitamin D3, fibroblast growth factor 23 and through effects of Ca2+-sensing receptor (CaSR) signaling. Disruption of Ca2+ homeostasis can result in altered blood Ca2+ levels and/or hypercalciuria, the latter is a phenomenon closely linked to the formation of kidney stones. Genetic alterations affecting renal Ca2+ handling can cause hypercalciuria, an area of expanding investigation. This review explores the molecular mechanisms governing Ca2+ homeostasis by the intestine and kidneys and discusses clinical aspects of genetic disorders associated with Ca2+-based kidney stone disease.

The identification of key molecules and pathways in the crosstalk of calcium oxalate-treated TCMK-1 cells and macrophage via exosomes

The interplay between crystals and epithelial cells forms the cornerstone of kidney stone development, communication between epithelial cells and macrophages emerging as a pivotal role in this process. We conducted next-generation sequencing on the secreted exosomes of TCMK-1 cells treated with calcium oxalate monohydrate (OX_EXO) or controls (NC_EXO), and on the macrophage cell line RAW264.7 stimulated with OX_EXO or NC_EXO, followed by validation of differentially expressed target proteins and miRNAs through Western blot and PCR. UPSET plots were employed to identify genes co-targeted by exosomal miRNAs. Various bioinformatic analyses were employed to predict potential mechanisms of the dysregulated genes. We integrated sequencing data from the GEO database, and validated findings using clinical patient urine and kidney tissues. We identified 665 differentially expressed exosomal miRNAs between OX_EXO and NC_EXO. Among the top 10 down-regulated miRNAs, the most targeted genes were AAK1 and NUFIP2, whereas PLCB1 was significantly targeted among the top 10 up-regulated miRNAs. In clinical specimens, we confirmed the differential expressions of five homologous miRNAs, as well as CNOT3, CNCNA1C, APEX1, and TMEM199. In conclusion, treatment of TCMK-1 cells with calcium oxalate significantly alerted the expression profile of exosomal miRNAs, subsequently influencing gene expression in macrophages, thereby modulating the processes of kidney stone formation.

Transcriptional activation of PINK1 by MyoD1 mediates mitochondrial homeostasis to induce renal calcification in pediatric nephrolithiasis

This study aims to uncover the molecular mechanisms underlying pediatric kidney stone formation induced by renal calcium deposition by utilizing high-throughput sequencing data to reveal the regulation of PINK1 by MyoD1. We performed transcriptome sequencing on peripheral blood samples from healthy children and children with kidney stones to obtain differentially expressed genes (DEGs). Genes related to mitochondrial oxidative stress were obtained from the Genecards website and intersected with DEGs to obtain candidate target genes. Additionally, we conducted protein-protein interaction (PPI) analysis using the STRING database to identify core genes involved in pediatric kidney stone disease (KSD) and predicted their transcription factors using the hTFtarget database. We assessed the impact of MyoD1 on the activity of the PINK1 promoter using dual-luciferase reporter assays and investigated the enrichment of MyoD1 on the PINK1 promoter through chromatin immunoprecipitation (ChIP) experiments. To validate our hypothesis, we selected HK-2 cells and established an in vitro kidney stone model induced by calcium oxalate monohydrate (COM). We evaluated the expression levels of various genes, cell viability, volume of adherent crystals in each group, as well as mitochondrial oxidative stress in cells by measuring mitochondrial membrane potential (Δψm), superoxide dismutase (SOD) activity, reactive oxygen species (ROS), and malondialdehyde (MDA) content. Mitochondrial autophagy was assessed using mtDNA fluorescence staining and Western blot analysis of PINK1-related proteins. Apoptosis-related proteins were evaluated using Western blot analysis, and cell apoptosis was measured using flow cytometry. Furthermore, we developed a rat model of KSD and assessed the expression levels of various genes, as well as the pathologic changes in rat renal tissues using H&E and von Kossa staining, transmission electron microscopy (TEM), and the expression of creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) to evaluate the mitochondrial oxidative stress in vivo (through measurement of Δψm, SOD activity, ROS, and MDA content). Mitochondrial autophagy was evaluated by Western blot analysis of PINK1-associated proteins. Apoptosis-related proteins were detected using Western blot analysis, and cellular apoptosis was examined using cell flow cytometry and TUNEL staining. Bioinformatics analysis revealed that the PINK1 gene is upregulated and vital in pediatric kidney stone patients. Our in vitro and in vivo experiments demonstrated that silencing PINK1 could inhibit kidney stone formation by suppressing mitochondrial oxidative stress both in vitro and in vivo. We identified MyoD1 as an upstream transcription factor of PINK1 that contributes to the occurrence of pediatric kidney stones through the activation of PINK1. Our in vivo and in vitro experiments collectively confirmed that silencing MyoD1 could inhibit mitochondrial oxidative stress, mitochondrial autophagy, and cellular apoptosis in a rat model of kidney stones by downregulating PINK1 expression, consequently suppressing the formation of kidney stones. In this study, we discovered that MyoD1 may promote kidney stone formation and development in pediatric patients by transcriptionally activating PINK1 to induce mitochondrial oxidative stress.