The genetics of kidney stone disease and nephrocalcinosis

Tips for Testing Adults With Suspected Genetic Kidney Disease

Genetic kidney disease is common but often unrecognized. It accounts for most cystic kidney diseases and tubulopathies, many forms of congenital abnormalities of the kidney and urinary tract (CAKUT), and some glomerulopathies. Genetic kidney disease is typically suspected where the disease usually has a genetic basis or there is another affected family member, a young age at onset, or extrarenal involvement, but there are also many exceptions to these "rules". Genetic testing requires the patient's written informed consent. When a patient declines testing, another later conversation may be worthwhile. Genetic testing not only indicates the diagnosis but also the inheritance pattern, likely at-risk family members, disease in other organs, clinical course, and possibly effective treatments. Sometimes genetic testing does not identify a pathogenic variant even where other evidence is strong. A variant of uncertain significance (VUS) may be reported but should not be used for clinical decision making. It may be reclassified after more information becomes available without necessarily retesting the patient. Patients should be provided with a copy of their genetic test report, the results explained, and at-risk family members offered "cascade" testing. A referral to a clinical geneticist or genetic counselor helps identify affected family members and in providing advice to assist with reproductive decisions.

Knowledge, attitudes, and practices towards urinary system stones among the Chengdu population

This cross-sectional study aimed to explore the knowledge, attitudes, and practices (KAP) regarding urinary system stones among the general public in Chengdu, China. Conducted between January and June 2023, this research targeted individuals undergoing physical examinations at the Health Management Center of Sichuan Provincial People's Hospital. Structured questionnaires were administered to collect demographic information and assess KAP related to urinary system stones. Following meticulous scrutiny, 1014 valid questionnaires were retained for analysis. The computed scores for knowledge, attitude, and practice were 9.36 ± 4.23 (possible score range 0-17), 37.75 ± 7.20 (possible score range 11-55), and 30.77 ± 4.00 (possible score range 10-50), respectively. These outcomes suggested insufficient knowledge and moderately positive attitudes and practices among the participants. Structural Equation Modeling (SEM) analysis revealed a direct impact of knowledge on attitude (β = 0.967, P < 0.001), with attitude subsequently exerting a direct influence on practice (β = 0.167, P < 0.001). This indicated an indirect impact of knowledge on practice. Additionally, there was a direct effect of knowledge on practice (β = 0.167, P < 0.001). In conclusion, the general populace in Chengdu exhibited insufficient knowledge and moderate attitudes and practices concerning urinary stones. These findings underscore the imperative for targeted educational interventions aimed at enhancing public awareness and fostering positive attitudes and practices toward urinary stone prevention and management.

Reclassification of Variants Following Renal Genetics Testing: Uncommon Yet Impactful for Diagnosis and Management

Introduction

Genetic testing is increasingly utilized in nephrology practice, but limited real-world data exist on variant reclassification following renal genetics testing.

Methods

A cohort of patients at the Cleveland Clinic Renal Genetics Clinic who underwent genetic testing through clinical laboratories was assessed with their clinical and laboratory data analyzed.

Results

Between January 2019 and June 2023, 425 new patients with variable kidney disorders from 413 pedigrees completed genetic testing through 10 clinical laboratories, including 255 (60%) females with median (25th, 75th percentiles) age of 36 (22-54) years. Multigene panel was the most frequently used modality followed by single-gene testing, exome sequencing (ES), chromosomal microarray (CMA), and genome sequencing (GS). At initial report, 52% of patients had ≥1 variants of uncertain significance (VUS) with or without concurrent pathogenic variant(s). Twenty amendments were issued across 19 pedigrees involving 19 variants in 17 genes. The overall variant reclassification rate was 5%, with 63% being upgrades and 32% downgrades. Of the reclassified variants, 79% were initially reported as VUS. The median time-to-amendments from initial reports was 8.4 (4-27) months. Following the variant reclassifications, 60% of the patients received a new diagnosis or a change in diagnosis. Among these, 67% of patients received significant changes in clinical management.

Conclusion

Variant reclassification following genetic testing is infrequent but important for diagnosis and management of patients with suspected genetic kidney disease. The majority of variant reclassifications involve VUS and are upgrades in clinically issued amended reports. Further studies are needed to investigate the predictors of such events.

The Impact of NLRP3 Inflammasome on Osteoblasts and Osteogenic Differentiation: A Literature Review

Osteoblasts (OBs), which are a crucial type of bone cells, derive from bone marrow mesenchymal stem cells (MSCs). Accumulating evidence suggests inflammatory cytokines can inhibit the differentiation and proliferation of OBs, as well as interfere with their ability to synthesize bone matrix, under inflammatory conditions. NLRP3 inflammasome is closely associated with cellular pyroptosis, which can lead to excessive release of pro-inflammatory cytokines, causing tissue damage and inflammatory responses, however, the comprehensive roles of NLRP3 inflammasome in OBs and their differentiation have not been fully elucidated, making targeting NLRP3 inflammasome approaches to treat diseases related to OBs uncertain. In this review, we provide a summary of NLRP3 inflammasome activation and its impact on OBs. We highlight the significant roles of NLRP3 inflammasome in regulating OBs differentiation and function. Furthermore, current available strategies to affect OBs function and osteogenic differentiation targeting NLRP3 inflammasome are listed and analyzed. Finally, through the prospective discussion, we seek to provide novel insights into the crucial role of NLRP3 inflammasome in diseases related to OBs and offer valuable information for devising treatment strategies.

A blood-based multi-omic landscape for the molecular characterization of kidney stone disease

Kidney stone disease (KSD, also named renal calculi, nephrolithiasis, or urolithiasis) is a common urological disease entailing the formation of minerals and salts that form inside the urinary tract, frequently caused by diabetes, high blood pressure, hypertension, and monogenetic components in most patients. 10% of adults worldwide are affected by KSD, which continues to be highly prevalent and with increasing incidence. For the identification of novel therapeutic targets in KSD, we adopted high-throughput sequencing and mass spectrometry (MS) techniques in this study and carried out an integrative analysis of exosome proteomic data and DNA methylation data from blood samples of normal and KSD individuals. Our research delineated the profiling of exosomal proteins and DNA methylation in both healthy individuals and those afflicted with KSD, finding that the overexpressed proteins and the demethylated genes in KSD samples are associated with immune responses. The consistency of the results in proteomics and epigenetics supports the feasibility of the comprehensive strategy. Our insights into the molecular landscape of KSD pave the way for a deeper understanding of its pathogenic mechanism, providing an opportunity for more precise diagnosis and targeted treatment strategies for KSD.

Carboxymethylated Rhizoma alismatis polysaccharides reduces the risk of calcium oxalate stone formation by reducing cellular inflammation and oxidative stress

This study aims to elucidate the mechanism and potential of Rhizoma alismatis polysaccharides (RAPs) in preventing oxidative damage to human renal proximal tubule epithelial cells. The experimental approach involved incubating HK-2 cells with 100 nm calcium oxalate monohydrate for 24 h to establish a cellular injury model. Protection was provided by RAPs with varying carboxyl group contents: 3.57%, 7.79%, 10.84%, and 15.33%. The safeguarding effect of RAPs was evaluated by analyzing relevant cellular biochemical indicators. Findings demonstrate that RAPs exhibit notable antioxidative properties. They effectively diminish the release of reactive oxygen species, lactate dehydrogenase, and malondialdehyde, a lipid oxidation byproduct. Moreover, RAPs enhance superoxide dismutase activity and mitochondrial membrane potential while attenuating the permeability of the mitochondrial permeability transition pore. Additionally, RAPs significantly reduce levels of inflammatory factors, including NLRP3, TNF-α, IL-6, and NO. This reduction corresponds to the inhibition of overproduced pro-inflammatory mediator nitric oxide and the caspase 3 enzyme, leading to a reduction in cellular apoptosis. RAPs also display the ability to suppress the expression of the HK-2 cell surface adhesion molecule CD44. The observed results collectively underscore the substantial anti-inflammatory and anti-apoptotic potential of all four RAPs. Moreover, their capacity to modulate the expression of cell surface adhesion molecules highlights their potential in inhibiting the formation of kidney stones. Notably, RAP3, boasting the highest carboxyl group content, emerges as the most potent agent in this regard.

Genetic susceptibility of urolithiasis: comprehensive results from genome-wide analysis

BACKGROUND

The pathogenesis of urolithiasis is multi-factorial and genetic factors have been shown to play a significant role in the development of urolithiasis. We tried to apply genome-wide Mendelian randomization (MR) analysis and figure out reliable gene susceptibility of urolithiasis from the largest samples to date in two independent genome-wide association studies (GWAS) database of European ancestry.

METHODS

We extracted summary statistics of expression quantitative trait locus (eQTL) from eQTLGen consortium. Urolithiasis phenotype information was obtained from both FinnGen Biobank and UK Biobank. Multiple two-sample MR analysis with a Bonferroni-corrected P threshold (P < 2.5e-06) was conducted. The primary endpoint was the causal effect calculated by random-effect inverse variance weighted (IVW) method. Sensitivity analysis, volcano plots, scatter plots, and regional plots were also performed and visualized.

RESULTS

After multiple MR tests between 19942 eQTLs and urolithiasis phenotype from both cohorts, 30 common eQTLs with consistent effect size direction were found to be causally associated with urolithiasis risk. Finally only one gene (LMAN2) was simultaneously identified among all top significant eQTLs from both FinnGen Biobank (beta = 0.6758, se = 0.0327, P = 6.775e-95) and UK Biobank (beta = 0.0044, se = 0.0009, P = 2.417e-06). We also found that LMAN2 was with the largest beta effect size on urolithiasis phenotype from the two cohorts.

CONCLUSION

We for the first time implemented genome-wide MR analysis to investigate the genetic susceptibility of urolithiasis in general population of European ancestry. Our results provided novel insights into common genetic variants of urinary stone disease, which was of great help to subsequent researches.

Monogenic features of urolithiasis: A comprehensive review

Objective

Urolithiasis formation has been attributed to environmental and dietary factors. However, evidence is accumulating that genetic background can contribute to urolithiasis formation. Advancements in the identification of monogenic causes using high-throughput sequencing technologies have shown that urolithiasis has a strong heritable component.

Methods

This review describes monogenic factors implicated in a genetic predisposition to urolithiasis. Peer-reviewed journals were evaluated by a PubMed search until July 2023 to summarize disorders associated with monogenic traits, and discuss clinical implications of identification of patients genetically susceptible to urolithiasis formation.

Results

Given that more than 80% of urolithiases cases are associated with calcium accumulation, studies have focused mainly on monogenetic contributors to hypercalciuric urolithiases, leading to the identification of receptors, channels, and transporters involved in the regulation of calcium renal tubular reabsorption. Nevertheless, available candidate genes and linkage methods have a low resolution for evaluation of the effects of genetic components versus those of environmental, dietary, and hormonal factors, and genotypes remain undetermined in the majority of urolithiasis formers.

Conclusion

The pathophysiology underlying urolithiasis formation is complex and multifactorial, but evidence strongly suggests the existence of numerous monogenic causes of urolithiasis in humans.

Drosophila ClC-c Is a Homolog of Human CLC-5 and a New Model for Dent Disease Type 1

Key Points

Drosophila can be a model for Dent Disease type 1. Drosophila Clc-C mutations function similar to human CLC-5 Dent 1 mutations.

Background

Drosophila serve as exceptional alternative models for in vivo and ex vivo research and may provide an avenue for in-depth investigation for human ClC-5 and Dent disease type 1 (DD1). The Drosophila ClC-c (CG5284) has sequence homology with human ClC-5 and is hypothesized to encompass similar functional and phenotypical roles with ClC-5 and variants that cause DD1.

Methods

Ion transport function and activity of Drosophila ClC-c and homologous DD1 variants were assessed by voltage clamp electrophysiology. Membrane localization was demonstrated in Drosophila expressing a GFP-labeled construct of ClC-c. Genetic expression of an RNAi against ClC-c mRNA was used to generate a knockdown fly that serves as a DD1 disease model. Tubule secretion of cations and protein were assessed, as well as the crystal formation in the Malpighian tubules.

Results

Voltage clamp experiments demonstrate that ClC-c is voltage-gated with Cl−-dependent and pH-sensitive currents. Inclusion of homologous DD1 mutations pathogenic variants (S393L, R494W, and Q777X) impairs ClC-c ion transport activity. In vivo expression of ClC-c-eGFP in Malpighian tubules reveals that the membrane transporter localizes to the apical membrane and nearby cytosolic regions. RNAi knockdown of ClC-c (48% decreased mRNA expression) causes increased secretion of both urinary protein and Ca2+ and increased occurrence of spontaneous tubule crystals.

Conclusions

Drosophila ClC-c shows orthologous function and localization to human ClC-5. Thus, Drosophila and ClC-c regulation may be useful for future investigations of Cl− transport, Ca2+ homeostasis, and urinary protein loss in DD1.

Nephrocalcinosis in Neonates

Nephrocalcinosis occurs in as many as 40% of preterm neonates. Many causes and contributors predispose neonates to develop nephrocalcinosis, including metabolic, genetic, and iatrogenic factors. Because nephrocalcinosis can be a manifestation of an underlying genetic disorder, neonates with nephrocalcinosis must undergo an evaluation to identify and address contributors, to prevent further renal calcium deposition that can potentially lead to renal dysfunction. In this article, we review the epidemiology, pathogenesis, diagnosis, and evaluation of nephrocalcinosis in neonates. We also summarize the natural history of nephrocalcinosis of prematurity as well as the management of this condition.

Urinary Acidification Does Not Explain the Absence of Nephrocalcinosis in a Mouse Model of Familial Hypomagnesaemia with Hypercalciuria and Nephrocalcinosis (FHHNC)

Patients with mutations in Cldn16 suffer from familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) which can lead to renal insufficiency. Mice lacking claudin-16 show hypomagnesemia and hypercalciuria, but no nephrocalcinosis. Calcium oxalate and calcium phosphate are the most common insoluble calcium salts that accumulate in the kidney in the case of nephrocalcinosis, however, the formation of these salts is less favored in acidic conditions. Therefore, urine acidification has been suggested to limit the formation of calcium deposits in the kidney. Assuming that urine acidification is causative for the absence of nephrocalcinosis in the claudin-16-deficient mouse model, we aimed to alkalinize the urine of these mice by the ablation of the subunit B1 of the vesicular ATPase in addition to claudin-16. In spite of an increased urinary pH in mice lacking claudin-16 and the B1 subunit, nephrocalcinosis did not develop. Thus, urinary acidification is not the only factor preventing nephrocalcinosis in claudin-16 deficient mice.

Tight junction and kidney stone disease

Defects of tight junction (TJ) are involved in many diseases related to epithelial cell functions, including kidney stone disease (KSD), which is a common disease affecting humans for over a thousand years. This review provides brief overviews of KSD and TJ, and summarizes the knowledge on crystal-induced defects of TJ in renal tubular epithelial cells (RTECs) in KSD. Calcium oxalate (CaOx) crystals, particularly COM, disrupt TJ via p38 MAPK and ROS/Akt/p38 MAPK signaling pathways, filamentous actin (F-actin) reorganization and α-tubulin relocalization. Stabilizing p38 MAPK signaling, reactive oxygen species (ROS) production, F-actin and α-tubulin by using SB239063, N-acetyl-L-cysteine (NAC), phalloidin and docetaxel, respectively, successfully prevent the COM-induced TJ disruption and malfunction. Additionally, genetic disorders of renal TJ, including mutations and single nucleotide polymorphisms (SNPs) of CLDN2, CLDN10b, CLDN14, CLDN16 and CLDN19, also affect KSD. Finally, the role of TJ as a potential target for KSD therapeutics and prevention is also discussed.

Habitual fish oil supplementation, genetic susceptibility of kidney stones and the risk of new-onset kidney stones

OBJECTIVE

We aimed to assess the association between habitual fish oil use and new-onset kidney stones in participants with different levels of genetic risks of kidney stones.

METHODS

477,311 participants free of kidney stones at baseline from the UK Biobank cohort were included. Fish oil use was collected by both food frequency questionnaires and 24-h dietary recalls. A genetic risk score (GRS) for kidney stones was calculated based on 20 single-nucleotide polymorphisms associated with kidney stones. The primary outcome was new-onset kidney stones.

RESULTS

During a median follow-up of 12.0 years, 5,637 cases of kidney stones were documented. Participants with high genetic risks of kidney stones had a higher risk of new-onset kidney stones (vs. low or intermediate risks; adjusted HR, 1.52; 95 %CI:1.44-1.60). Compared with non-users, habitual use of fish oil was associated with a lower risk of new-onset kidney stones (adjusted HR, 0.84, 95 %CI, 0.78-0.92) in participants with low or intermediate genetic risks, but not in those with high genetic risks of kidney stones (adjusted HR, 1.02, 95 %CI, 0.93-1.12; P-interaction =0.001). Among those with low or intermediate genetic risks of kidney stones, compared with fish oil constant nonusers, the adjusted HRs (95 %CI) for kidney stones were 0.89 (0.75-1.06), 0.72 (0.58-0.90), and 0.79 (0.64-0.97), for fish oil occasional users, modestly constant users, and moderately and highly constant users (P for trend = 0.001), respectively.

CONCLUSIONS

Habitual fish oil use was associated with a lower risk of new-onset kidney stones in participants with low or intermediate genetic risk of kidney stones.

Positive association between ambient air pollutants and incident kidney stones

We aimed to assess the association between exposure to various air pollutants, individually or jointly, and incident kidney stones, and examine whether genetic susceptibility for kidney stones may modify this association. 453,977 participants without prior kidney stones from the UK Biobank were included. Annual mean concentrations of PM2.5, PM2.5-10, PM10, NO2, and NOx were estimated with a land use regression model. A weighted air pollution score was constructed that incorporates the five pollutants mentioned above. A genetic risk score (GRS) was calculated based on 20 single-nucleotide polymorphisms associated with kidney stones. The primary outcome was incident kidney stones. During a median follow-up of 11.9 years, 5,375 kidney stones were recorded. The adjusted HRs (95%CI) of incident kidney stones were 1.04 (1.01-1.07), 1.02 (1.00-1.05), 1.03 (1.01-1.06), 1.05 (1.02-1.08), and 1.04 (1.01-1.07), for per standard deviation (SD) increment in PM2.5 (SD:1.06 μg/m3), PM2.5-10 (SD:0.90 μg/m3), PM10 (SD:1.90 μg/m3), NO2 (SD:7.63 μg/m3), and NOx (SD: 15.63 μg/m3), respectively. Moreover, there was a significantly linear association between the air pollution score and incident kidney stones (per SD increment: HR, 1.05, 95%CI: 1.02-1.08), especially in those without diabetes (vs. participants with diabetes; P-interaction = 0.037). In addition, the association between air pollution and kidney stones was statistically significant only in participants within intermediate-high kidney stone GRS, but not in those with low GRS kidney stone, though the interaction was not significant (P-interaction = 0.385). In conclusion, exposure to air pollution was associated with a higher risk of incident kidney stones, calling for the need to improve air quality.

Inverse association of glucosamine use and risk of new-onset kidney stones in UK adults with less sedentary time

OBJECTIVE

To assess the association of different sedentary behaviors and glucosamine use with the risk of kidney stones and examine the modification of genetic risk of kidney stones on this association.

METHODS

473,225 participants free of kidney stones at baseline from the UK Biobank were included. Total sedentary time was calculated as the sum of the duration of TV-watching, driving, and non-occupational computer using. The primary outcome was new-onset kidney stones.

RESULTS

During a median follow-up of 12.0 years, 5528 cases of kidney stones were documented. All major sedentary behaviors and total sedentary time were significantly positively related to the risk of kidney stones (All P for trend<0.05). Participants with total sedentary time ≥ 3.5 h/day had a significantly higher risk of new-onset kidney stones (vs. <3.5 h/day [tertile 1]; HR, 1.18; 95%CI,1.10-1.27). Compared with non-users, participants who regularly used glucosamine had a significantly lower risk of new-onset kidney stones in those with total sedentary time < 3.5 h/day (HR, 0.72; 95%CI,0.59-0.86), but not in those with total sedentary time ≥ 3.5 h/day (HR, 0.99; 95%CI,0.91-1.08; P-interaction = 0.001). Among participants with total sedentary time < 3.5 h/day, there was a dose-response relationship of glucosamine use with new-onset kidney stones (P for trend<0.001). Genetic risks of kidney stones did not significantly modify the association.

CONCLUSIONS

TV-watching, driving and non-occupational computer using were all positively associated with the risk of new-onset kidney stones. Glucosamine use was associated with a lower risk of new-onset kidney stones in participants with total sedentary time < 3.5 h/day, following a dose-response relationship.

Hydration for Adult Patients with Nephrolithiasis: Specificities and Current Recommendations

Nephrolithiasis affects around 10% of the population and is frequently associated with impaired dietary factors. The first one is insufficient fluid intake inducing reduced urine volume, urine supersaturation, and subsequently urinary lithiasis. Kidneys regulate 24 h urine volume, which, under physiological conditions, approximately reflects daily fluid intake. The aim of this study is to synthesize and highlight the role of hydration in the treatment of nephrolithiasis. Increasing fluid intake has a preventive effect on the risk of developing a first kidney stone (primary prevention) and also decreases the risk of stone recurrence (secondary prevention). Current guidelines recommend increasing fluid intake to at least at 2.5 L/day to prevent stone formation, and even to 3.5-4 L in some severe forms of nephrolithiasis (primary or enteric hyperoxaluria or cystinuria). Fluid intake must also be balanced between day and night, to avoid urinary supersaturation during the night. Patients should be informed and supported in this difficult process of increasing urine dilution, with practical ways and daily routines to increase their fluid intake. The liquid of choice is water, which should be chosen depending on its composition (such as calcium, bicarbonate, or magnesium content). Finally, some additional advice has to be given to avoid certain beverages such as those containing fructose or phosphoric acid, which are susceptible to increase the risk of nephrolithiasis.

Integrative genome-wide analyses identify novel loci associated with kidney stones and provide insights into its genetic architecture

Kidney stone disease (KSD) is a complex disorder with high heritability and prevalence. We performed a large genome-wide association study (GWAS) meta-analysis for KSD to date, including 720,199 individuals with 17,969 cases in European population. We identified 44 susceptibility loci, including 28 novel loci. Cell type-specific analysis pinpointed the proximal tubule as the most relevant cells where susceptibility variants might act through a tissue-specific fashion. By integrating kidney-specific omics data, we prioritized 223 genes which strengthened the importance of ion homeostasis, including calcium and magnesium in stone formation, and suggested potential target drugs for the treatment. The genitourinary and digestive diseases showed stronger genetic correlations with KSD. In this study, we generate an atlas of candidate genes, tissue and cell types involved in the formation of KSD. In addition, we provide potential drug targets for KSD treatment and insights into shared regulation with other diseases.

Clinical and biochemical footprints of inherited metabolic diseases. XIV. Metabolic kidney diseases

Kidney disease is a global health burden with high morbidity and mortality. Causes of kidney disease are numerous, extending from common disease groups like diabetes and arterial hypertension to rare conditions including inherited metabolic diseases (IMDs). Given its unique anatomy and function, the kidney is a target organ in about 10% of known IMDs, emphasizing the relevant contribution of IMDs to kidney disease. The pattern of injury affects all segments of the nephron including glomerular disease, proximal and distal tubular damage, kidney cyst formation, built-up of nephrocalcinosis and stones as well as severe malformations. We revised and updated the list of known metabolic etiologies associated with kidney involvement and found 190 relevant IMDs. This represents the 14th of a series of educational articles providing a comprehensive and revised list of metabolic differential diagnoses according to system involvement.

Identification of mutations in 15 nephrolithiasis-related genes leading to a molecular diagnosis in 85 Chinese pediatric patients

BACKGROUND

The aim of this study was to describe the genotypic and phenotypic characteristics of Chinese pediatric patients with hereditary nephrolithiasis.

METHODS

Whole-exome sequencing (WES) was performed on 218 Chinese pediatric patients with kidney stones, and genetic and clinical data were collected and analyzed retrospectively.

RESULTS

The median age at onset in our cohort was 2.5 years (age range, 0.3-13 years). We detected 79 causative mutations in 15 genes, leading to a molecular diagnosis in 38.99% (85/218) of all cases. Monogenic mutations were present in 80 cases, and digenic mutations were present in 5 cases; 34.18% (27/79) of mutations were not included in the databases. Six common mutant genes, i.e., HOGA1, AGXT, GRHPR, SLC3A1, SLC7A9, and SLC4A1, were found in 84.71% of the patients overall. Furthermore, three mutations (A278A, c.834_834 + 1GG > TT, and C257G) in HOGA1, two mutations (K12QfX156 and S275RfX28) in AGXT, and one mutation (C289DfX22) in GRHPR represented hotspot mutations. The patients with HOGA1 mutations had the earliest onset age (0.8 years), followed by those with SLC7A9 (1.8 years), SLC4A1 (2.7 years), AGXT (4.3 years), SLC3A1 (4.8 years), and GRHPR (8 years) mutations (p = 0.002). Nephrocalcinosis was most commonly observed in patients with AGXT gene mutations.

CONCLUSIONS

Fifteen causative genes were detected in 85 Chinese pediatric patients with kidney stone diseases. The most common mutant genes, novel mutations, hotspot mutations, and genotype-phenotype correlations were also found. This study contributes to the understanding of genetic profiles and clinical courses in pediatric patients with hereditary nephrolithiasis. A higher resolution version of the Graphical abstract is available as Supplementary information.

Melatonin exerts a protective effect in ameliorating nephrolithiasis via targeting AMPK/PINK1-Parkin mediated mitophagy and inhibiting ferroptosis in vivo and in vitro

Hyperoxaluria-induced damage to renal tubular epithelial cells (RTECs) is considered the most significant contributor to kidney stone formation. However, the precise regulatory mechanism underlying this damage, particularly its association with mitophagy dysfunction, remains unclear. Additionally, effective preventive medications for kidney stones are lacking. Melatonin, a hormone secreted by the pituitary gland that primarily regulates circadian rhythm, has been found to modulate mitophagy in recent research. Therefore, this investigation aims to examine the impact of melatonin on mitophagy and cellular impairment in the formation of kidney stone. The results of this study reveal that melatonin can alleviate the formation of kidney stones and reduce oxalate-induced renal injuries. In the RTECs of kidney stone model, mitophagy was found to be impaired, leading to increased oxidative stress, inflammation, and ferroptosis both in vivo and in vitro. Melatonin was shown to have a restorative potential in enhancing PINK1-Parkin-regulated mitophagy through AMPK phosphorylation, reducing excessive ROS release and inhibiting oxidative stress, inflammation and ferroptosis. Further experiments demonstrated that the protective effect of melatonin was diminished by PINK1 knockdown and AMPK pathway blockade. This study is the first to reveal the interplay between mitophagy and ferroptosis in kidney stone models and establish the protective role of melatonin in restoring mitophagy to inhibit ferroptosis.

Protective Effect of Alkaline Mineral Water on Calcium Oxalate-Induced Kidney Injury in Mice

Background

Kidney stone disease induces chronic renal insufficiency by crystal-induced renal tubular epithelial cell injury. It has been reported that the prevalence of kidney stone disease is increasing, accompanied by the high recurrence rate. Alkaline mineral water has been reported to possess beneficial effects to attenuate inflammation. Here, we explored the potential protective effects and underlying mechanisms of alkaline mineral water against calcium oxalate-induced kidney injury.

Methods

We performed the mice kidney stone model by administering glyoxylate at 100 mg/kg once daily for 7 days. To assess the effects of alkaline mineral water on oxalate-induced kidney injury, mice drank different water (distilled water, natural mineral water at pH = 8.0, as well as natural mineral water at pH = 9.3) for 7 days, respectively, followed by glyoxylate exposure. After collection, crystal formation, kidney injury and cell apoptosis, fibrosis, oxidative stress, as well as inflammation were measured.

Results

Our results showed that glyoxylate treatment led to kidney crystal formation and fibrosis, which can be attenuated by drinking alkaline mineral water. Furthermore, alkaline mineral water also reduced kidney injury and cell apoptosis, oxidative stress, and inflammation.

Conclusion

Alkaline mineral water supplement prevents progression of glyoxylate-induced kidney stones through alleviating oxidative stress and inflammation.

Critical role of VHL/BICD2/STAT1 axis in crystal-associated kidney disease

Nephrolithiasis is highly prevalent and associated with the increased risk of kidney cancer. The tumor suppressor von Hippel-Lindau (VHL) is critical for renal cancer development, however, its role in kidney stone disease has not been fully elucidated until now. Here we reported VHL expression was upregulated in renal epithelial cells upon exposure to crystal. Utilizing Vhl+/mu mouse model, depletion of VHL exacerbated kidney inflammatory injury during nephrolithiasis. Conversely, overexpression of VHL limited crystal-induced lipid peroxidation and ferroptosis in a BICD2-depdendent manner. Mechanistically, VHL interacted with the cargo adaptor BICD2 and promoted itsd K48-linked poly-ubiquitination, consequently resulting in the proteasomal degradation of BICD2. Through promoting STAT1 nuclear translocation, BICD2 facilitated IFNγ signaling transduction and enhanced IFNγ-mediated suppression of cystine/glutamate antiporter system Xc-, eventually increasing cell sensitivity to ferroptosis. Moreover, we found that the BRAF inhibitor impaired the association of VHL with BICD2 through triggering BICD2 phosphorylation, ultimately causing severe ferroptosis and nephrotoxicity. Collectively, our results uncover the important role of VHL/BICD2/STAT1 axis in crystal kidney injury and provide a potential therapeutic target for treatment and prevention of renal inflammation and drug-induced nephrotoxicity.

Obstructive nephropathy and molecular pathophysiology of renal interstitial fibrosis

The kidneys play a key role in maintaining total body homeostasis. The complexity of this task is reflected in the unique architecture of the organ. Ureteral obstruction greatly affects renal physiology by altering hemodynamics, changing glomerular filtration and renal metabolism, and inducing architectural malformations of the kidney parenchyma, most importantly renal fibrosis. Persisting pathological changes lead to chronic kidney disease, which currently affects ∼10% of the global population and is one of the major causes of death worldwide. Studies on the consequences of ureteral obstruction date back to the 1800s. Even today, experimental unilateral ureteral obstruction (UUO) remains the standard model for tubulointerstitial fibrosis. However, the model has certain limitations when it comes to studying tubular injury and repair, as well as a limited potential for human translation. Nevertheless, ureteral obstruction has provided the scientific community with a wealth of knowledge on renal (patho)physiology. With the introduction of advanced omics techniques, the classical UUO model has remained relevant to this day and has been instrumental in understanding renal fibrosis at the molecular, genomic, and cellular levels. This review details key concepts and recent advances in the understanding of obstructive nephropathy, highlighting the pathophysiological hallmarks responsible for the functional and architectural changes induced by ureteral obstruction, with a special emphasis on renal fibrosis.

YAP/ACSL4 Pathway-Mediated Ferroptosis Promotes Renal Fibrosis in the Presence of Kidney Stones

The potential association between calcium oxalate stones and renal fibrosis has been extensively investigated; however, the underlying mechanisms remain unclear. Ferroptosis is a novel form of cell death characterized by iron-dependent lipid peroxidation and regulated by acyl coenzyme A synthase long-chain family member 4 (ACSL4). Yes-associated protein (YAP), a transcriptional co-activator in the Hippo pathway, promotes ferroptosis by modulating ACSL4 expression. Nevertheless, the involvement of YAP-ACSL4 axis-mediated ferroptosis in calcium oxalate crystal deposition-induced renal fibrosis and its molecular mechanisms have not been elucidated. In this study, we investigated ACSL4 expression and ferroptosis activation in the kidney tissues of patients with calcium oxalate stones and in mice using single-cell sequencing, transcriptome RNA sequencing, immunohistochemical analysis, and Western blot analysis. In vivo and in vitro experiments demonstrated that inhibiting ferroptosis or ACSL4 mitigated calcium oxalate crystal-induced renal fibrosis. Furthermore, YAP expression was elevated in the kidney tissues of patients with calcium oxalate stones and in calcium oxalate crystal-stimulated human renal tubular epithelial cell lines. Mechanistically, in calcium oxalate crystal-stimulated human renal tubular epithelial cell lines, activated YAP translocated to the nucleus and enhanced ACSL4 expression, consequently inducing cellular ferroptosis. Moreover, YAP silencing suppressed ferroptosis by downregulating ACSL4 expression, thereby attenuating calcium oxalate crystal-induced renal fibrosis. Conclusively, our findings suggest that YAP-ACSL4-mediated ferroptosis represents an important mechanism underlying the induction of renal fibrosis by calcium oxalate crystal deposition. Targeting the YAP-ACSL4 axis and ferroptosis may therefore hold promise as a potential therapeutic approach for preventing renal fibrosis in patients with kidney stones.

Associations of exposure to heavy metal mixtures with kidney stone among U.S. adults: A cross-sectional study

Assessing the effects of heavy metals (HMs) on kidney stone is often limited to analyzing individual metal exposures, with studies on the effects of exposure to mixtures of HMs being scarce. To comprehensively evaluate the relationship between exposure to mixed HMs and kidney stones, we analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 2007-2016, which included 7809 adults. We used multiple statistical methods, including multiple logistic regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp) and bayesian kernel machine regression (BKMR), to assess the association between single HM and mixed exposure to HMs and kidney stones. Firstly, in single exposure analysis, urinary cadmium (Cd) and cobalt (Co) demonstrated a positive association with the risk of kidney stones. Secondly, various other approaches consistently revealed that mixed exposure to HMs exhibited a positive association with kidney stone risk, primarily driven by Cd, Co, and barium (Ba) in urine, with these associations being particularly notable among the elderly population. Finally, both BKMR and survey-weighted generalized linear models consistently demonstrated a significant synergistic effect between urinary Co and urinary uranium (Ur) in elevating the risk of kidney stones. Overall, this study provides new epidemiological evidence that mixed exposure to HMs is associated with an increased risk of kidney stones. Further prospectively designed studies are needed to confirm these findings.

Causal relationship between kidney stones and gut microbiota contributes to the gut-kidney axis: a two-sample Mendelian randomization study

Background

Gut microbiota, particularly Oxalobacter formigenes, has been previously reported to be associated with kidney stones. However, the conflicting results from both observational and intervention studies have created substantial uncertainty regarding the contribution of Oxalobacter formigenes to the formation of kidney stone.

Methods

We employed a two-sample MR analysis to investigate the causal relationship between gut microbiota and kidney stones using GWASs summary statistics obtained from the MiBioGen and FinnGen consortia. Moreover, we conducted a reserve MR analysis to assess the direction of the causal associations between gut microbiota and kidney stones. The inverse variance weighted (IVW) approach represents the primary method of Mendelian Randomization (MR) analysis.

Results

Our analyses do not yield supportive evidence for a causal link between the genus Oxalobacter (OR = 0.99, 95% CI: 0.90-1.09, p = 0.811) and the formation of kidney stones. The order Actinomycetales (OR = 0.79, 95% CI: 0.65-0.96, p = 0.020), family Actinomycetaceae (OR = 0.79, 95% CI: 0.65-0.96, p = 0.019), family Clostridiaceae 1 (OR = 0.80, 95% CI: 0.67-0.96, p = 0.015), genus Clostridiumsensustricto 1 (OR = 0.81, 95% CI: 0.67-0.98, p = 0.030) and genus Hungatella (OR = 0.86, 95% CI: 0.74-0.99, p = 0.040) had protective effects on kidney stones, and the genus Haemophilus (OR = 1.16, 95% CI: 1.01-1.33, p = 0.032), genus Ruminococcaceae (UCG010) (OR = 1.38, 95% CI: 1.04-1.84, p = 0.028), genus Subdoligranulum (OR = 1.27, 95% CI: 1.06-1.52, p = 0.009) were risk factors for kidney stones. Differential abundance analysis provide no evidence of a association between Oxalobacter formigenes and kidney stones, and showed genus Subdoligranulum were risk factors for kidney stones. Reverse MR analysis did not indicate any causal association of kidney stones on gut microbiota. No considerable heterogeneity of instrumental variables or horizontal pleiotropy was observed.

Conclusion

Our two-sample MR study did not find any causal relationship between genus Oxalobacter and kidney stones. The association between gut microbiota and kidney stones does not solely depend on the presence of genus Oxalobacter/Oxalobacter formigenes. A more integrated approach using multiple omics platforms is needed to better understand the pathogenesis of kidney stones in the context of complex gene-environment interactions over time.

Association of serum bicarbonate with the development of kidney stones in patients with chronic kidney disease: a retrospective cohort study

BACKGROUND

Epidemiological studies demonstrate an association between kidney stones and risk of chronic kidney disease (CKD) and CKD progression. Metabolic acidosis, as a consequence of CKD, results in a reduced urine pH which promotes the formation of some types of kidney stones and inhibits the formation of others. While metabolic acidosis is a risk factor for CKD progression, the association of serum bicarbonate with risk of incident kidney stones is not well understood.

METHODS

We used an Integrated Claims-Clinical dataset of US patients to generate a cohort of patients with non-dialysis-dependent CKD with two serum bicarbonate values of 12 to <22 mmol/L (metabolic acidosis) or 22 to <30 mmol/L (normal serum bicarbonate). Primary exposure variables were baseline serum bicarbonate and change in serum bicarbonate over time. Cox proportional hazards models evaluated time to first occurrence of kidney stones during a median 3.2-year follow-up.

RESULTS

A total of 142 884 patients qualified for the study cohort. Patients with metabolic acidosis experienced post-index date kidney stones at greater frequency than patients with normal serum bicarbonate at the index date (12.0% vs 9.5%, P < .0001). Both lower baseline serum bicarbonate [hazard ratio (HR) 1.047; 95% confidence interval (CI) 1.036-1.057] and decreasing serum bicarbonate over time (HR 1.034; 95% CI 1.026-1.043) were associated with increased risk of kidney stone development.

CONCLUSIONS

Metabolic acidosis was associated with a higher incidence of kidney stones and shorter time to incident stone formation in patients with CKD. Future studies may investigate the role of correcting metabolic acidosis to prevent stone formation.

Research progress on renal calculus associate with inborn error of metabolism

Renal calculus is a common disease with complex etiology and high recurrence rate. Recent studies have revealed that gene mutations may lead to metabolic defects which are associated with the formation of renal calculus, and single gene mutation is involved in relative high proportion of renal calculus. Gene mutations cause changes in enzyme function, metabolic pathway, ion transport, and receptor sensitivity, causing defects in oxalic acid metabolism, cystine metabolism, calcium ion metabolism, or purine metabolism, which may lead to the formation of renal calculus. The hereditary conditions associated with renal calculus include primary hyperoxaluria, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis, Bartter syndrome, primary distal renal tubular acidosis, infant hypercalcemia, hereditary hypophosphatemic rickets with hypercalciuria, adenine phosphoribosyltransferase deficiency, hypoxanthine-guanine phosphoribosyltransferase deficiency, and hereditary xanthinuria. This article reviews the research progress on renal calculus associated with inborn error of metabolism, to provide reference for early screening, diagnosis, treatment, prevention and recurrence of renal calculus.

GC-MS based metabolite profiling, antioxidant and antiurolithiatic properties of apple cider vinegar

Aim

To perform in vitro analysis of antioxidant and antiurolithiasis to carry out GC-MS-based metabolite profile.

Materials & methods

The effect of apple cider vinegar (ACV) in vitro, antioxidant and GC-MS analysis was evaluated. The antioxidant studies were performed. In vitro techniques included nucleation, aggregation and growth assay.

Results & conclusion

The presence of polyphenols, flavonoids, alkaloids and carbohydrates was shown. Concentrations from 5-30 μg/ml could dissolve calcium oxalate (p < 0.05) in vitro. The IC₅₀ value of ACV in DPPH was found to be around 7 μg/ml and the IC₅₀ value of the ACV in ABTS assay was around 9 μg/ml. Different phytocompounds were obtained from GC-MS analysis. ACV can be consumed to prevent kidney stones which seems helpful to the current therapy.

Pediatric urolithiasis: what can pediatricians expect from radiologists?

The incidence of urolithiasis in children has increased over the two last decades. Urolithiasis formation results from urine oversaturation following insufficient water intake, urinary obstruction (notably in cases of congenital uropathies), excess production of an insoluble compound, or imbalance between crystallization promoters and inhibitors. Whereas most urolithiases in adults occur secondary to environmental factors, in children, secondary causes are far more frequent, and 15% are related to genetic causes, most often monogenic. This is especially true in recurrent forms, with early and rapid progression and bilateral stones, and in cases of familial history or consanguinity. Because of differing clinical management, one should rule out cystinuria, primary hyperoxaluria and renal tubular acidosis, among other causes of urolithiasis. As such, a complete biochemical evaluation must be performed in all cases of pediatric urolithiasis, even in cases of an underlying uropathy. Ultrasound examination is the first-line modality for imaging pediatric urolithiasis, allowing both diagnosis (urolithiasis and its complications) and follow-up. US examination should also explore clues to an underlying cause of urolithiasis. This review is focused on the role of imaging in the management and etiological assessment of pediatric urolithiasis. Radiologists play an important role in pediatric urolithiasis, facilitating diagnosis, follow-up and surgical management. A trio of clinicians (pediatric nephrologist, pediatric surgeon, pediatric radiologist) is thus necessary in the care of these pediatric patients.

Fifty years of basic and clinical renal stone research: have we achieved major breakthroughs? A debate

PURPOSE OF REVIEW

After 50 years of basic and clinical renal stone research, it is appropriate to evaluate whether breakthroughs have been achieved and if so, how they may be harnessed to combat stone disease therapeutically and prophylactically.

RECENT FINDINGS

Regarding stone therapeutics and prophylaxis, recent innovative studies are sparse. Researchers have resorted to publishing articles derived from data mining. Stone incidence and prevalence have increased during the past 50 years, suggesting the absence of any major breakthroughs. However, new sciences and technologies have created fresh opportunities. Information technology stores huge epidemiological databases leading to identification of new risk factors. Genetic coding has prompted identification of monogenic diseases associated with urolithiasis. Genome-wide association studies in combination with epigenomics, transcriptomics, proteomics, and metabolomics are providing new insights. High-throughput and culture-independent techniques promise to define the impact of microbiome on stone formation while artificial intelligent techniques contribute to diagnosis and prediction of treatment outcomes. These technologies, as well as those which are advancing surgical treatment of stones represent major breakthroughs in stone research.

SUMMARY

Although efforts to cure stones have not yielded major breakthroughs, technological advances have improved surgical management of this disease and represent significant headway in applied stone research.

Breaking the Cycle of Recurrent Calcium Stone Disease

Calcium stones are common and recurrent in nature, yet few therapeutic tools are available for secondary prevention. Personalized approaches for stone prevention have been informed by 24-hour urine testing to guide dietary and medical interventions. However, current evidence is conflicting about whether an approach guided by 24-hour urine testing is more effective than a generic one. The available medications for stone prevention, namely thiazide diuretics, alkali, and allopurinol, are not always prescribed consistently, dosed correctly, or tolerated well by patients. New treatments on the horizon hold the promise of preventing calcium oxalate stones by degrading oxalate in the gut, reprogramming the gut microbiome to reduce oxalate absorption, or knocking down expression of enzymes involved in hepatic oxalate production. New treatments are also needed to target Randall's plaque, the root cause of calcium stone formation.

Lemon-Derived Extracellular Vesicle-like Nanoparticles Block the Progression of Kidney Stones by Antagonizing Endoplasmic Reticulum Stress in Renal Tubular Cells

Kidney stones, represented by the calcium oxalate (CaOx) type, are highly prevalent and recrudescent. Cumulative evidence shows regular consumption of lemonade intervenes with stone development. However, the detailed mechanism remains obscure. Here, extracellular vesicle-like nanoparticles (LEVNs) isolated from lemonade are demonstrated to traffick from the gut to the kidney, primarily enriched in tubule cells. Oral administration of LEVNs significantly alleviates the progression of kidney stones in rats. Mechanistically, in addition to altering the crystallization of CaOx toward a less stable subtype, LEVNs suppress the CaOx-induced endoplasmic reticulum stress response of tubule cells, as indicated by homeostasis of specific signaling molecules and restoration of subcellular function, thus indirectly inhibiting stone formation. To exercise this regulation, endocytosed LEVNs traffick along the microtubules throughout the cytoplasm and are eventually recruited into lysosomes. In conclusion, this study reveals a LEVNs-mediated mechanism against renal calculi and provides positive evidence for consumption of lemonade preventing stone formation.

The role of genetic testing in the diagnostic workflow of pediatric patients with kidney diseases: the experience of a single institution

PURPOSE

Inherited kidney diseases are among the leading causes of kidney failure in children, resulting in increased mortality, high healthcare costs and need for organ transplantation. Next-generation sequencing technologies can help in the diagnosis of rare monogenic conditions, allowing for optimized medical management and therapeutic choices.

METHODS

Clinical exome sequencing (CES) was performed on a cohort of 191 pediatric patients from a single institution, followed by Sanger sequencing to confirm identified variants and for family segregation studies.

RESULTS

All patients had a clinical diagnosis of kidney disease: the main disease categories were glomerular diseases (32.5%), ciliopathies (20.4%), CAKUT (17.8%), nephrolithiasis (11.5%) and tubular disease (10.5%). 7.3% of patients presented with other conditions. A conclusive genetic test, based on CES and Sanger validation, was obtained in 37.1% of patients. The highest detection rate was obtained for ciliopathies (74.4%), followed by nephrolithiasis (45.5%), tubular diseases (45%), while most glomerular diseases and CAKUT remained undiagnosed.

CONCLUSIONS

Results indicate that genetic testing consistently used in the diagnostic workflow of children with chronic kidney disease can (i) confirm clinical diagnosis, (ii) provide early diagnosis in the case of inherited conditions, (iii) find the genetic cause of previously unrecognized diseases and (iv) tailor transplantation programs.

Perioperative Fast-Track Surgery Nursing Intervention for Patients with Kidney Stone Disease under Computed Tomography Imaging

This research aims to analyze the clinical intervention effect of perioperative fast-track surgery (FTS) nursing on patients with kidney stone disease (KSD) under computed tomography (CT) imaging. One-hundred KSD patients were selected as research objects and grouped after CT examination. These objects were randomly divided into a research group (FTS nursing intervention, n = 50) and a control group (general routine nursing intervention, n = 50). The preoperative psychological status of patients was compared between the two groups, using Self-rating Anxiety Scale and Self-rating Depression Scale. The hunger and thirst situations were compared using Numerical Rating Scale; postoperative recovery time, incidence of complications, and nursing satisfaction were also compared. The high-density shadow could be clearly observed in the right kidney of the patients in the CT imaging examination. The nursing outcomes suggested that there was no notable difference in hunger between the two groups, and anxiety, depression, and thirst in the research group were highly better than those in the control group (P < 0.01). The time of the first exhaust, the time of body temperature returning to normal, the time of getting out of bed, and the length of hospital stay in the research group were all shorter than those in the control group (P < 0.05). The total postoperative satisfaction of the research group (98.00%) was greatly better than the 88.00% in the control group (P < 0.05). As the FTS concept was applied in the perioperative nursing of KSD patients under CT imaging, the preoperative and postoperative negative emotions of patients could be improved. Thereby, the postoperative recovery rate of patients was promoted, postoperative complications and patients' pain were reduced, and the postoperative quality of life of patients was also improved.

High ambient temperature increases the number of emergency visits for upper urolithiasis in Hefei City, China

Background

Few studies have examined the effect of ambient temperature on upper urolithiasis in developing countries, with even fewer considering individual factors.

Methods

The present study analyzed data on emergency department visits for upper urolithiasis from three hospital sites of a large hospital in Hefei, China, during 2016-2020. Data on environmental factors during the same period were also analyzed. A time series analysis employing a generalized Poisson regression model (GPRM) combined with a distributed lag non-linear model (DLNM) was conducted to evaluate the effect of ambient temperature on the number of emergency department visits for upper urolithiasis.

Results

We found that ambient temperatures above 9 °C were positively associated with the frequency of upper urolithiasis visits, with the relationship being most significant on the current day and with a one-day lag. In the single-day lag effect, the most significant relative risk (RR) for mild heat (75th percentile) and high heat (95th percentile) was 1.229 (95% CI: 1.100-1.373) and 1.337 (95% CI: 1.134-1.577), respectively. The cumulative lag effect was significantly higher than the single-day lag effect, with maximum relative risks (RRs) of 1.779 (95% CI: 1.356-2.335) and 2.498 (95% CI: 1.688-3.697), respectively. The maximum lag time was 7 days. RRs were also higher among women and individuals aged 30-44 years.

Conclusions

Increased ambient temperature is a risk factor for upper urolithiasis, and there is a hysteresis effect. Women and individuals aged 30-44 years are the most susceptible.

Network pharmacology and experimental validation to elucidate the pharmacological mechanisms of Bushen Huashi decoction against kidney stones

INTRODUCTION

Kidney stone disease (KS) is a complicated disease with an increasing global incidence. It was shown that Bushen Huashi decoction (BSHS) is a classic Chinese medicine formula that has therapeutic benefits for patients with KS. However, its pharmacological profile and mechanism of action are yet to be elucidated.

METHODS

The present study used a network pharmacology approach to characterize the mechanism by which BSHS affects KS. Compounds were retrieved from corresponding databases, and active compounds were selected based on their oral bioavailability (≥30) and drug-likeness index (≥0.18). BSHS potential proteins were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, whereas KS potential genes were obtained from GeneCards and OMIM, TTD, and DisGeNET. Gene ontology and pathway enrichment analysis were used to determine potential pathways associated with genes. The ingredients of BSHS extract were identified by the ultra-high-performance liquid chromatography coupled with quadrupole orbitrap mass spectrometry (UHPLC-Q/Orbitrap MS). The network pharmacology analyses predicted the potential underlying action mechanisms of BSHS on KS, which were further validated experimentally in the rat model of calcium oxalate kidney stones.

RESULTS

Our study found that BSHS reduced renal crystal deposition and improved renal function in ethylene glycol(EG)+ammonium chloride(AC)-induced rats, and also reversed oxidative stress levels and inhibited renal tubular epithelial cell apoptosis in rats. BSHS upregulated protein and mRNA expression of E2, ESR1, ESR2, BCL2, NRF2, and HO-1 in EG+AC-induced rat kidney while downregulating BAX protein and mRNA expression, consistent with the network pharmacology results.

DISCUSSION

This study provides evidence that BSHS plays a critical role in anti-KS via regulation of E2/ESR1/2, NRF2/HO-1, and BCL2/BAX signaling pathways, indicating that BSHS is a candidate herbal drug for further investigation in treating KS.

Use of whole-exome sequencing to identify novel monogenic gene mutations and genotype-phenotype correlations in Chinese Han children with urolithiasis

The incidence of urolithiasis (UL) in children has been increasing. Although the pathogenesis of pediatric UL is controversial and remains unclear, multiple monogenic causes of UL have been identified. We aim to investigate the prevalence of inherited UL causes and explore the genotype-phenotype correlation in a Chinese pediatric group. In this study, we analyzed the DNA of 82 pediatric UL patients using exome sequencing (ES). The data of metabolic evaluation and genomic sequencing were subsequently analyzed together. We detected 54 genetic mutations in 12 of 30 UL-related genes. A total of 15 detected variants were described as pathogenic mutations, and 12 mutations were considered likely pathogenic. Molecular diagnoses were made in 21 patients with pathogenic or likely pathogenic variants. Six novel mutations that were not previously reported were identified in this cohort. Calcium oxalate stones were detected in 88.9% cases (8/9) with hyperoxaluria-related mutations, while 80% of individuals (4/5) with cystinuria-causing defects were diagnosed with cystine stones. Our study highlights the significant genetic abnormalities in pediatric UL and demonstrates the diagnostic power of ES for screening patients with UL.

Comparison of the Effects of Laparoscopic Surgery and Traditional Open Surgery on Stone Clearance, Laboratory Indexes and Life Quality in Patients with Renal Calculi

Objective

A case-control study was conducted to determine the effectiveness of laparoscopic surgery and traditional open surgery on stone clearance, laboratory indexes, and life quality in patients with renal calculi.

Methods

During March 2017 to March 2022, 272 patients with complex renal calculi (CRC) cured in our hospital were assigned into control group (n = 136) and research group (n = 136) arbitrarily. The former accepted traditional open surgery, while the latter accepted laparoscopic surgery. The operation time, intraoperative blood loss, hospital stay, and time of getting out of bed were compared. The degree of postoperative incision pain was assessed by visual analogue scale (VAS). The life quality was assessed by the Comprehensive Assessment Questionnaire-74 (GQOL-74). The indexes of renal function and urine metabolism were measured. Then, the postoperative stone clearance rate and complications were calculated.

Results

Operation time, blood loss intraoperatively, time out of bed, and hospitalization were all remarkably reduced in the research group, and the difference was statistically significant (P < 0.05). The complete stone clearance rates in study and control cohorts were 75.73% and 63.24%, respectively. The VAS scores were lessened after the operation. Compared with the two groups, the VAS scores of the research group were remarkably lower at 1 to 2 weeks and 1 and 3 months after the operation, and the difference was statistically significant (P < 0.05). One week after operation, the levels of β 2-microglobulin (β 2-MG), N-acetyl-β-glucosaminidase (NAG), and renal injury molecule-1 (kidney injury molecule-1, Kim-1) in the research group were remarkably lower. The levels of urinary β 2-MG, NAG, and KIM-1 in the research group were remarkably lower, and the difference was statistically significant (P < 0.05). One week after operation, the levels of urinary oxalic acid, uric acid, and urinary calcium lessened averagely. The levels of urinary oxalic acid, uric acid, and urinary calcium in the research group were lower, and the difference was statistically significant (P < 0.05). The quality-of-life scores were compared. One week after the operation, the scores of physical function, psychological function, social function, and material function were all augmented, and the difference was statistically significant (P < 0.05). The incidence of complications was 9.56% and 2.21%, respectively. The incidence of complications in the research group was lower, and the difference was statistically significant (P < 0.05).

Conclusion

Laparoscopic surgery is successful when treating CRC, which is superior to invasive surgery in postoperative complications, stone clearance rate, improvement of postoperative renal function, and life quality. It is one of the ideal treatment methods for CRC. However, the role of open surgery when treating CRC cannot be ignored. This needs to be further confirmed by large samples of randomized controlled trials.

CAV1 alleviated CaOx stones formation via suppressing autophagy-dependent ferroptosis

Background

Calcium oxalate (CaOx) is the most common type of kidney stone, but the mechanism of CaOx stones formation remains unclear. The injury of renal cells such as ferroptosis and autophagy has been considered a basis for stones formation.

Methods

We conducted transmission electron microscope (TEM), reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), and C11-BODIPY analysis to explore whether CaOx could induce autophagy-dependent ferroptosis in vivo and in vitro. To explore the possible mechanism, we conducted bioinformatic analysis of patients with or without CaOx stones, Western blot and qPCR were used to identify the different genes we found in bioinformatic analysis.

Results

In our study, we found that CaOx could induce autophagy-dependent ferroptosis no matter in vivo or in vitro, which might finally lead to urolithiasis. Bioinformatic analysis of the GSE73680 dataset indicated that the expression of caveolin-1 (CAV1) was higher in control patients than CaOx stone patients, the STRING database indicated that CAV1 might interact with low density lipoprotein receptro-related protein 6 (LRP6), Gene Set Enrichment Analysis (GSEA) showed that the WNT pathway positively associated with the control group while negatively related to the stone group, and LRP6 was the core gene of the WNT pathway. Western blot found that CAV1, LRP6, and Wnt/β-Catenin were decreased in Human Kidney2 (HK2) cells stimulated with CaOx. Furthermore, the WNT pathway was considered to be involved in autophagy and ferroptosis.

Conclusions

We presumed that CAV1 could ameliorate autophagy-dependent ferroptosis through the LRP6/Wnt/β-Catenin axis, and finally alleviate CaOx stone formation.

Dietary copper intake and the prevalence of kidney stones among adult in the United States: A propensity score matching study

Background

Trace metals are essential trace elements for the human body, but insufficient or excessive levels of metal ions can lead to the development of disease. The purpose of this study was to examine the relationship between dietary intake of copper and the prevalence of kidney stones in U.S. adult population.

Methods

We included data on dietary intake of trace metals from 28,623 adult participants in the National Health and Nutrition Examination Survey (NHANES) database between 2007 and 2018. Multivariate logistic regression and restricted cubic spline (RCS) dose-response curves were used to explore the association between trace metals and kidney stones, and 1:1 propensity score matching (PSM) was performed between the stone formers and non-stone formers to test the validity of the results.

Results

Dose-response curves showed a non-linear negative association between dietary copper intake and kidney stones, and an increase in copper intake reduced the risk of kidney stones. Multivariate logistic regression analysis showed that the odds ratio (95% confidence interval) for kidney stones in each quartile of copper intake compared to the lowest quartile were 0.905 (0.808-1.011, p = 0.075), 0.880 (0.785-0.987, p = 0.028) and 0.853 (0.756-0.959, p = 0.009). In addition, similar conclusions were reached after analysis of PSM in the stone formers and non-stone formers groups.

Conclusion

Dietary copper intake was negatively and non-linearly correlated with kidney stones, which is worthy of further research and application in clinical practice.

Skeletal and extraskeletal disorders of biomineralization

The physiological process of biomineralization is complex and deviation from it leads to a variety of diseases. Progress in the past 10 years has enhanced understanding of the genetic, molecular and cellular pathophysiology underlying these disorders; sometimes, this knowledge has both facilitated restoration of health and clarified the very nature of biomineralization as it occurs in humans. In this Review, we consider the principal regulators of mineralization and crystallization, and how dysregulation of these processes can lead to human disease. The knowledge acquired to date and gaps still to be filled are highlighted. The disorders of mineralization discussed comprise a broad spectrum of conditions that encompass bone disorders associated with alterations of mineral quantity and quality, as well as disorders of extraskeletal mineralization (hyperphosphataemic familial tumoural calcinosis). Included are disorders of alkaline phosphatase (hypophosphatasia) and phosphate homeostasis (X-linked hypophosphataemic rickets, fluorosis, rickets and osteomalacia). Furthermore, crystallopathies are covered as well as arterial and renal calcification. This Review discusses the current knowledge of biomineralization derived from basic and clinical research and points to future studies that will lead to new therapeutic approaches for biomineralization disorders.

Heterocyclic Aromatic Amines and Risk of Kidney Stones: A Cross-Sectional Study in US Adults

Background

Heterocyclic aromatic amines (HAAs) are a group of harmful substances produced while cooking meat at high temperatures. This study aimed to investigate the relationship between HAAs and the occurrence of kidney stones.

Methods

Data on the level of four HAAs, including 2-Amino-9H-pyrido [2, 3-b] indole (A-α-C), 1-Methyl-9H-pyrido [3, 4-b] indole (Harman), 9H-Pyrido [3, 4-b] indole (Norharman), and 2-Amino-1-methyl-6-phenylimidazo [4, 5-b] pyridine (PhIP), in the urine from adult participants were extracted from the 2013–2014 NHANES database. Propensity score matching (PSM) was used to balance confounding variables between the stone former and non-stone former groups, and logistic regression analysis was performed to analyze the relationship between HAAs and the occurrence of kidney stones.

Results

Of the 1,558 eligible participants, a history of kidney stones was self-reported by 140 (9.0%). Compared to non-stone formers, stone formers had higher concentrations of A-α-C, Harman, and Norharman and lower concentrations of PhlP in urine. After adjusting for all other confounding variables, multivariate logistic regression analysis showed that the high-Harman group had a higher risk of kidney stones than the low-Harman group [adjusted odds ratios (aOR) = 1.618, 95% CI: 1.076–2.433, p = 0.021]. After PSM analysis, Harman concentration remained a risk factor for kidney stones (high-Harman group vs. low-Harman group: aOR = 1.951, 95% CI: 1.059–3.596, p = 0.032).

Conclusion

Increased urinary Harman concentrations are associated with an increased risk of kidney stones in the general US population.

Physical Activity Reduces the Effect of High Body Mass Index on Kidney Stones in Diabetes Participants From the 2007–2018 NHANES Cycles: A Cross-Sectional Study

Background

Body mass index (BMI) is a vital risk factor for kidney stones, but physical activity may reduce the incidence of kidney stones. However, it remains unknown whether physical activity reduces the effect of high BMI on kidney stones in diabetes participants.

Methods

We included clinical information from 4,008 adult participants with diabetes from the National Health and Nutrition Examination Survey (NHANES) database from 2007 to 2018. Univariate and multivariate logistic regression analyses were used to analyze the relationship between BMI and kidney stones, as well as the risk of BMI and kidney stones in different physical activity subgroups.

Results

A total of 4,008 diabetic participants were included in this study, of whom 652 (16.3%) self-reported a history of kidney stones. Logistic regression analysis showed a positive association between BMI and kidney stones. After adjusting for other confounders, the adjusted ORs for the risk of kidney stones was 1.514 (95% CI, 1.134–2.022, p = 0.005) for participants with BMI ≥30 kg/m² among all participants; the risk of kidney stones was elevated (OR = 1.572, 95% CI, 1.134–2.022, p = 0.005) in group without physical activity, and a reduced risk (OR = 1.421, 95% CI, 0.847–2.382, p = 0.183) in the group with physical activity. Furthermore, similar results were found in most subgroups.

Conclusion

Our study suggests that high BMI is a risk factor for diabetes kidney stone participants and that physical activity may moderate this relationship to some extent.

Genetic Polymorphisms and Kidney Stones Around the Globe: A Systematic Review and Meta-Analysis

Objective: This study explores associations between recurrent kidney stones and genetic polymorphisms.

Methods: Meta-analysis of polymorphisms in renal stone cases versus control groups. Four electronic databases (PubMed, SCOPUS, EMBASE, and Web of Science) were searched up to 30 May 2021, using the keywords: “kidney stone” or “kidney calculi,” or “urolithiasis” or “nephrolithiasis” or “urinary calculi” and “genome” or “genetic” or “mutation” or “single nucleotide polymorphism.” Forrest plots, ORs, 95% CI, Chi-square (χ2)-test, and index of heterogeneity (I2) were calculated. Only studies with Newcastle–Ottawa scale (NOS) ≥ 6 were included for quality control, and Funnel, Begg’s, and Eager’s plots assessed publication bias. PROSPERO: CRD42022250427.

Results: Among 7,671 searched articles, 72 were included. Polymorphisms in VDR (OR: 1.20; 95% CI: 1.06–1.36), CASR (OR = 1.24; 95% CI: 1.01–1.52), Osteopontin (OR = 1.38; 95% CI: 1.09–1.74), and Urokinase genes (OR = 1.52; 95% CI: 1.02–2.28) showed a significant association with risk of urinary stone formation, while Klotho gene showed a protective effect (OR = 0.75; 95% CI: 0.57–0.99). The VDR gene polymorphism was frequent in Asians, whereas CASR polymorphism was frequent in European and North American populations.

Conclusion: Multifactorial nature of the stone formation, emphasizing the role of environmental factors, might explain contradictory results in the literature. While polymorphisms in VDR, CASR, Osteopontin, and Urokinase genes were associated with urinary stone formation, the Klotho gene showed a protective effect.