The status and characteristics of urinary stone composition in China

Potassium sodium hydrogen citrate intervention on gut microbiota and clinical features in uric acid stone patients

The high recurrence rate of renal uric acid stone (UAS) poses a significant challenge for urologists, and potassium sodium hydrogen citrate (PSHC) has been proven to be an effective oral dissolution drug. However, no studies have investigated the impact of PSHC on gut microbiota and its metabolites during stone dissolution therapy. We prospectively recruited 37 UAS patients and 40 healthy subjects, of which 12 patients completed a 3-month pharmacological intervention. Fasting vein blood was extracted and mid-stream urine was retained for biochemical testing. Fecal samples were collected for 16S ribosomal RNA (rRNA) gene sequencing and short chain fatty acids (SCFAs) content determination. UAS patients exhibited comorbidities such as obesity, hypertension, gout, and dyslipidemia. The richness and diversity of the gut microbiota were significantly decreased in UAS patients, Bacteroides and Fusobacterium were dominant genera while Subdoligranulum and Bifidobacterium were poorly enriched. After PSHC intervention, there was a significant reduction in stone size accompanied by decreased serum uric acid and increased urinary pH levels. The abundance of pathogenic bacterium Fusobacterium was significantly downregulated following the intervention, whereas there was an upregulation observed in SCFA-producing bacteria Lachnoclostridium and Parasutterella, leading to a significant elevation in butyric acid content. Functions related to fatty acid synthesis and amino acid metabolism within the microbiota showed upregulation following PSHC intervention. The correlation analysis revealed a positive association between stone pathogenic bacteria abundance and clinical factors for stone formation, while a negative correlation with SCFAs contents. Our preliminary study revealed that alterations in gut microbiota and metabolites were the crucial physiological adaptation to PSHC intervention. Targeted regulation of microbiota and SCFA holds promise for enhancing drug therapy efficacy and preventing stone recurrence. KEY POINTS: • Bacteroides and Fusobacterium were identified as dominant genera for UAS patients • After PSHC intervention, Fusobacterium decreased and butyric acid content increased • The microbiota increased capacity for fatty acid synthesis after PSHC intervention.

Selenium participates in the formation of kidney stones by alleviating endoplasmic reticulum stress and apoptosis of renal tubular epithelial cells

Objectives: To investigate the role of selenium and selenium-containing proteins in the etiology and pathogenesis of kidney stones.Methods: The HK-2 cell line was subjected to supersaturation oxalate treatment to establish an in vitro model of calcium oxalate kidney stones, while SD rats were administered with ethylene glycol to establish an in vivo model of calcium oxalate kidney stones. qPCR analysis was employed to investigate the alterations in selenoproteins within the models, and subsequently, genes exhibiting significant changes were identified. Subsequently, based on the functions of these genes, their regulatory effects on endoplasmic reticulum stress (ERS) and apoptosis during the disease progression were examined both in HK-2 cells and rat kidneys. Finally, Selenomethionine (SeMet) supplementation was introduced to explore its therapeutic potential for kidney stone management.Results: The involvement of Selenoprotein K in the pathogenesis of calcium oxalate kidney stone disease has been confirmed, exhibiting significant alterations. Manipulation of its expression levels through overexpression and knockdown techniques resulted in a corresponding reduction or increase in oxidative stress, ERS, and apoptosis within renal tubular epithelial cells. SelK regulates ERS and apoptosis by controlling the IRE1-ASK1-JNK pathway. In addition, SeMet treatment, which contains selenium, effectively reduced the levels of oxidative stress, ERS, and apoptosis in vivo and in vitro models, thereby alleviating tubular epithelial cell damage and reducing the formation of kidney stones in experimental rats.Discussion: Selenium is involved in the occurrence and development of kidney stones by regulating oxidative damage to renal tubular epithelial cells. The results suggest that dietary selenium supplementation in daily life may be of great significance for the prevention and treatment of kidney stones.

Inflammatory factors and the risk of urolithiasis: a bidirectional Mendelian randomization study

Background

Urolithiasis is a prevalent condition encountered in urology. Over the past decade, its global incidence has been on an upward trajectory; paired with a high recurrence rate, this presents considerable health and economic burdens. Although inflammatory factors are pivotal in the onset and progression of urolithiasis, their causal linkages remain elusive.

Method

Mendelian randomization (MR) is predicated upon genome-wide association studies (GWASs). It integrates bioinformatics analyses to reveal causal relationships between exposures and outcomes, rendering it an effective method with minimized bias. Drawing from a publicly accessible GWAS meta-analysis comprising 8,293 samples, we identified 41 genetic variations associated with inflammatory cytokines as instrumental variables. Outcome data on upper urinary tract stones, which included renal and ureteral stones (9,713 cases and 366,693 controls), and lower urinary tract stones, including bladder and urethral stones (1,398 cases and 366,693 controls), were derived from the FinnGen Consortium R9 dataset. By leveraging the bidirectional MR methodology, we aimed to decipher the causal interplay between inflammatory markers and urolithiasis.

Results

Our study comprehensively elucidated the association between genetic inflammatory markers and urolithiasis via bidirectional Mendelian randomization. Post-MR analysis of the 41 genetic inflammation markers revealed that elevated levels of circulating interleukin-2 (IL-2) (OR = 0.921, 95% CI = 0.848-0.999) suggest a reduced risk for renal stone disease, while heightened stem cell growth factor beta (SCGF-β) (OR = 1.150, 95% CI = 1.009-1.310) and diminished macrophage inflammatory protein 1 beta (MIP-1β) (OR = 0.863, 95% CI = 0.779-0.956) levels suggest an augmented risk for lower urinary tract stones. Furthermore, renal stone disease appeared to elevate IL-2 (β = 0.145, 95% CI = 0.013-0.276) and cutaneous T cell-attracting chemokine (CTACK) (β = 0.145, 95% CI = 0.013-0.276) levels in the bloodstream, whereas lower urinary tract stones were linked to a surge in interleukin-5 (IL-5) (β = 0.142, 95% CI = 0.057-0.226), interleukin-7 (IL-7) (β = 0.108, 95% CI = 0.024-0.192), interleukin-8 (IL-8) (β = 0.127, 95% CI = 0.044-0.210), growth regulated oncogene alpha (GRO-α) (β = 0.086, 95% CI = 0.004-0.169), monokine induced by interferon-gamma (MIG) (β = 0.099, 95% CI = 0.008-0.191) and macrophage inflammatory protein 1 alpha (MIP-1α) (β = 0.126, 95% CI = 0.044-0.208) levels.

Conclusion

These discoveries intimate the instrumental role of IL-2 in the onset and progression of upper urinary tract stones. SCGF-β and MIP-1β influence the development of lower urinary tract stones. Urolithiasis also impacts the expression of cytokines such as IL-2, CTACK, IL-5, IL-7, IL-8, GRO-α, MIG, and MIP-1α. There is a pressing need for further investigation to ascertain whether these biomarkers can be harnessed to prevent or treat urolithiasis.

Serum metabolomics study reveals a distinct metabolic diagnostic model for renal calculi

Renal calculi (RC) represent a prevalent disease of the urinary system characterized by a high incidence rate. The traditional clinical diagnosis of RC emphasizes imaging and stone composition analysis. However, the significance of metabolic status in RC diagnosis and prevention remains unclear. This study aimed to investigate serum metabolites in RC patients to identify those associated with RC and to develop a metabolite-based diagnostic model. We employed nontargeted metabolomics utilizing ultra-performance liquid chromatography‒mass spectrometry (UPLC‒MS) to compare serum metabolites between RC patients and healthy controls. Our findings demonstrated significant disparities in serum metabolites, particularly in fatty acids and glycerophospholipids, between the two groups. Notably, the glycerophospholipid (GP) metabolic pathway in RC patients was significantly disrupted. Logistic regression models using differentially abundant metabolites revealed that elevated levels of 2-butyl-4-methyl phenol and reduced levels of phosphatidylethanolamine (P-16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) had the most substantial effect on RC risk. Overall, our study indicates that RC induces notable alterations in serum metabolites and that the diagnostic model based on these metabolites effectively distinguishes RC. This research offers promising insights and directions for further diagnostic and mechanistic studies on RC.

FTH1 overexpression using a dCasRx translation enhancement system protects the kidney from calcium oxalate crystal-induced injury

The engineered clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) system is currently widely applied in genetic editing and transcriptional regulation. The catalytically inactivated CasRx (dCasRx) has the ability to selectively focus on the mRNA coding region without disrupting transcription and translation, opening up new avenues for research on RNA modification and protein translation control. This research utilized dCasRx to create a translation-enhancement system for mammals called dCasRx-eIF4GI, which combined eukaryotic translation initiation factor 4G (eIF4GI) to boost translation levels of the target gene by recruiting ribosomes, without affecting mRNA levels, ultimately increasing translation levels of different endogenous proteins. Due to the small size of dCasRx, the dCasRx-eIF4GI translation enhancement system was integrated into a single viral vector, thus optimizing the delivery and transfection efficiency in subsequent applications. Previous studies reported that ferroptosis, mediated by calcium oxalate (CaOx) crystals, significantly promotes stone formation. In order to further validate its developmental potential, it was applied to a kidney stone model in vitro and in vivo. The manipulation of the ferroptosis regulatory gene FTH1 through single-guide RNA (sgRNA) resulted in a notable increase in FTH1 protein levels without affecting its mRNA levels. This ultimately prevented intracellular ferroptosis and protected against cell damage and renal impairment caused by CaOx crystals. Taken together, this study preliminarily validated the effectiveness and application prospects of the dCasRx-eIF4GI translation enhancement system in mammalian cell-based disease models, providing novel insights and a universal tool platform for protein translation research and future therapeutic approaches for nephrolithiasis.

Exploring the association between multiple factors and urolithiasis: A retrospective study and Mendelian randomization analysis

To investigate the relationship between several factors and urinary stone as well as different stone compositions. To guide the diagnosis, treatment, and prevention of urinary stone recurrence. We used bidirectional Mendelian randomization to analyze the causal relationship between hypertension and urinary stones, diabetes and urinary stones, and body mass index (BMI) and urinary stones. We retrospectively analyzed the medical records of patients with urinary stones admitted to a tertiary care hospital in Chongqing, China, from July 2015 to October 2022. Patients were included when they were first diagnosed with urinary stones. The odds ratio of calculi on hypertension estimated by inverse variance weighted was 8.46 (95%CI: 4.00-17.90, P = 2.25 × 10-8). The stone composition analysis showed that there were 3101 (67.02%) mixed, 1322 (28.57%) calcium oxalate monohydrate, 148 (3.20%) anhydrous uric acid, 16 (0.35%) magnesium ammonium phosphate hexahydrate, 11 (0.24%) dicalcium phosphate dihydrate, 10 (0.22%) carbonate apatite, 8 (0.17%) L-cystine, 4 ammonium uric acid (0.09%), and 7 other stone types (0.15%). Mendelian randomization studies have proven that urinary stones may be a potential risk factor for hypertension, while there is no causal relationship between diabetes and stones, BMI, and stones. Our retrospective study has shown that urinary stone components are closely associated with sex, age, hypertension, diabetes, and BMI. It is reasonable to suspect that treating a single stone component is ineffective in preventing recurrence. We also found that the peak incidence of urinary stones was at the most active stage of most people's working lives.

Development and Application of the CRISPR-dcas13d-eIF4G Translational Regulatory System to Inhibit Ferroptosis in Calcium Oxalate Crystal-Induced Kidney Injury

The CRISPR-Cas system, initially for DNA-level gene editing and transcription regulation, has expanded to RNA targeting with the Cas13d family, notably the RfxCas13d. This advancement allows for mRNA targeting with high specificity, particularly after catalytic inactivation, broadening the exploration of translation regulation. This study introduces a CRISPR-dCas13d-eIF4G fusion module, combining dCas13d with the eIF4G translation regulatory element, enhancing target mRNA translation levels. This module, using specially designed sgRNAs, selectively boosts protein translation in targeted tissue cells without altering transcription, leading to notable protein expression upregulation. This system is applied to a kidney stone disease model, focusing on ferroptosis-linked GPX4 gene regulation. By targeting GPX4 with sgRNAs, its protein expression is upregulated in human renal cells and mouse kidney tissue, countering ferroptosis and resisting calcium oxalate-induced cell damage, hence mitigating stone formation. This study evidences the CRISPR-dCas13d-eIF4G system's efficacy in eukaryotic cells, presenting a novel protein translation research approach and potential kidney stone disease treatment advancements.

A nomogram clinical prediction model for predicting urinary infection stones: development and validation in a retrospective study

PURPOSE

This study aimed to develop a nomogram prediction model to predict the exact probability of urinary infection stones before surgery in order to better deal with the clinical problems caused by infection stones and take effective treatment measures.

METHODS

We retrospectively collected the clinical data of 390 patients who were diagnosed with urinary calculi by imaging examination and underwent postoperative stone analysis between August 2018 and August 2023. The patients were randomly divided into training group (n = 312) and validation group (n = 78) using the "caret" R package. The clinical data of the patients were evaluated. Univariate and multivariate logistic regression analysis were used to screen out the independent influencing factors and construct a nomogram prediction model. The receiver operating characteristic curve (ROC), calibration curves, and decision curve analysis (DCA) and clinical impact curves were used to evaluate the discrimination, accuracy, and clinical application efficacy of the prediction model.

RESULTS

Gender, recurrence stones, blood uric acid value, urine pH, and urine bacterial culture (P < 0.05) were independent predictors of infection stones, and a nomogram prediction model ( https://zhaoyshenjh.shinyapps.io/DynNomInfectionStone/ ) was constructed using these five parameters. The area under the ROC curve of the training group was 0.901, 95% confidence interval (CI) (0.865-0.936), and the area under the ROC curve of the validation group was 0.960, 95% CI (0.921-0.998). The results of the calibration curve for the training group showed a mean absolute error of 0.015 and the Hosmer-Lemeshow test P > 0.05. DCA and clinical impact curves showed that when the threshold probability value of the model was between 0.01 and 0.85, it had the maximum net clinical benefit.

CONCLUSIONS

The nomogram developed in this study has good clinical predictive value and clinical application efficiency can help with risk assessment and decision-making for infection stones in diagnosing and treating urolithiasis.

Histone deacetylase 6 suppression of renal tubular epithelial cell promotes interstitial mineral deposition via alpha-tubulin acetylation

Randall's plaque (RP) is derived from interstitial mineral deposition and is highly prevalent in renal calcium oxalate (CaOx) stone disease, which is predictive of recurrence. This study shows that histone deacetylase 6 (HDAC6) levels are suppressed in renal tubular epithelial cells in RP samples, in kidney tissues of hyperoxaluria rats, and in hyper-oxalate-treated or mineralized cultured renal tubular epithelial (MDCK) cells in vitro. Mineral deposition in MDCK cells was exacerbated by HDAC6 inhibition but alleviated by HDAC6 overexpression. Surprisingly, the expression of some osteogenic-associated proteins, were not increased along with the increasing of mineral deposition, and result of single-cell RNA sequencing of renal papillae samples revealed that epithelial cells possess lower calcific activity, suggesting that osteogenic-transdifferentiation may not have actually occurred in tubular epithelial cells despite mineral deposition. The initial mineral depositions facilitated by HDAC6 inhibitor were localized in extracellular dome rather than inside the cells, moreover, suppression of HDAC6 significantly increased the calcium content of co-cultured renal interstitial fibroblasts (NRK49F) and enhanced mineral deposition of indirectly co-cultured NRK49F cells, suggesting that HDAC6 may influence trans-MDCK monolayer secretion of mineral. Further experiments revealed that this regulatory role was partially alpha-tubulinLys40 acetylation dependent. Collectively, these results suggest that hyper-oxalate exposure led to HDAC6 suppression in renal tubular epithelial cells, which may contribute to interstitial mineral deposition by promoting alpha-tubulinLys40 acetylation. Therapeutic agents that influence HDAC6 activity may be beneficial in preventing RP and CaOx stone formation.

Composition analysis of renal and ureteral calculi in a single center in northern China in the past decade

The current report aimed to evaluate the characteristics of stone composition in 3637 renal and ureteral calculi patients in a single center while clarifying its relationship with sex, age, and time. Out of 3637 cases of upper urinary tract stones, stone specimens were analyzed retrospectively. There were 2373 male patients aged 6 months-87 years, with an average age of 44.73 ± 15.63 years, and 1264 female patients aged 4 months-87 years, with an average age of 46.84 ± 16.00 years. The male-female ratio was 1.88:1. Five hundred twelve patients had ureteral calculi, and 3125 had renal calculi. The SPSS software helped analyze the relationship between renal and ureteral calculi composition and sex, age, and time. Stone composition demonstrated 2205 cases of calcium oxalate stones (60.6%), 518 carbonate apatite (14.2%), 386 uric acids (10.6%), 232 magnesium ammonium phosphate (6.4%), 117 calcium phosphate (3.2%), 76 cystine (2.1%), 47 sodium urate (1.3%), 31 others (0.9%), and 25 ammonium urate (0.7%) cases. The overall male-to-female sex ratio was 1.88:1. Stones in the upper urinary tract were significantly more frequent in men than in women between the ages of 31 and 60. However, such stones were significantly more frequent in women than men over 80 (P < .05). Cystine, Sodium urate, Carbonated apatite, and uric acid indicated significant differences between different age categories (all P < .001). Stone composition analyses revealed that the frequency of calcium oxalate calculi has increased annually, while cystine and carbonated apatite incidences have dropped annually over the past decade. The components of renal and ureteral calculi vary significantly based on age and sex, with calcium oxalate calculi being more frequent in men while magnesium ammonium phosphate stones are more frequent in female patients. The age between 31 and 60 years is the most prevalent for renal and ureteral calculi in men and women.

Dysregulated palmitic acid metabolism promotes the formation of renal calcium-oxalate stones through ferroptosis induced by polyunsaturated fatty acids/phosphatidic acid

The pathogenesis of renal calcium-oxalate (CaOx) stones is complex and influenced by various metabolic factors. In parallel, palmitic acid (PA) has been identified as an upregulated lipid metabolite in the urine and serum of patients with renal CaOx stones via untargeted metabolomics. Thus, this study aimed to mechanistically assess whether PA is involved in stone formation. Lipidomics analysis of PA-treated renal tubular epithelial cells compared with the control samples revealed that α-linoleic acid and α-linolenic acid were desaturated and elongated, resulting in the formation of downstream polyunsaturated fatty acids (PUFAs). In correlation, the levels of fatty acid desaturase 1 and 2 (FADS1 and FADS2) and peroxisome proliferator-activated receptor α (PPARα) in these cells treated with PA were increased relative to the control levels, suggesting that PA-induced upregulation of PPARα, which in turn upregulated these two enzymes, forming the observed PUFAs. Lipid peroxidation occurred in these downstream PUFAs under oxidative stress and Fenton Reaction. Furthermore, transcriptomics analysis revealed significant changes in the expression levels of ferroptosis-related genes in PA-treated renal tubular epithelial cells, induced by PUFA peroxides. In addition, phosphatidyl ethanolamine binding protein 1 (PEBP1) formed a complex with 15-lipoxygenase (15-LO) to exacerbate PUFA peroxidation under protein kinase C ζ (PKC ζ) phosphorylation, and PKC ζ was activated by phosphatidic acid derived from PA. In conclusion, this study found that the formation of renal CaOx stones is promoted by ferroptosis of renal tubular epithelial cells resulting from PA-induced dysregulation of PUFA and phosphatidic acid metabolism, and PA can promote the renal adhesion and deposition of CaOx crystals by injuring renal tubular epithelial cells, consequently upregulating adhesion molecules. Accordingly, this study provides a new theoretical basis for understanding the correlation between fatty acid metabolism and the formation of renal CaOx stones, offering potential targets for clinical applications.

Risk assessment and prevention of urolithiasis in urban areas of Baoding, China

Urolithiasis, or the formation of calculi in the urinary system, represents a prevalent urological condition frequently encountered among individuals aged 30 to 55 years. An in-depth analysis of the composition of these calculi holds significant promise in shedding light on the underlying etiological and pathogenic factors contributing to this ailment. The primary objective of this study was to delineate the principal components comprising urinary system calculi within a cohort of patients who sought medical intervention at a tertiary grade A hospital located in Baoding City. Furthermore, our investigation entailed a comprehensive examination of the physical and morphological characteristics exhibited by these calculi. In this study, a total of 2307 individuals afflicted with urinary system calculi were recruited as participants, and a corresponding number of 2307 calculous specimens were subjected to thorough examination. The specimens were examined using infrared spectroscopy. We collected and examined patient data including gender, age, location of the calculi, employment status, residential area, and other factors. The middle-aged demographic exhibited a conspicuous predilection for urinary system calculi, wherein a notable gender disparity was observed, with a male-to-female ratio of 1.63 to 1. Among the enrolled patients, kidney calculi were prevalent in 1270 cases, ureteral calculi were documented in 983 cases, and bladder calculi were encountered in 46 instances. Notably, the principal components comprising these calculi were identified as calcium oxalate and apatite, while uric acid and ammonium magnesium phosphate were comparatively less frequently encountered. Furthermore, the analysis of calculus composition across patients residing in distinct geographical regions did not reveal any statistically significant variations. The identification of components within upper urinary tract calculi plays a pivotal role in elucidating the root causes of calculus formation. This valuable information empowers healthcare professionals, particularly nursing staff, to provide personalized dietary and health guidance to patients, thereby enhancing the quality of care and promoting more effective management of this condition.

Mixed stones: urinary stone composition, frequency and distribution by gender and age

Proper analysis of urinary stone composition is a cornerstone for diagnosis, targeted treatment and recurrence prevention of urolithiasis. The aim of this study was to determine the composition, frequency and distribution of mixed stones according to gender and age of patients. A total of 42,519 urinary stones from 30,311 men and 12,208 women submitted between January 2007 and December 2020 were studied. Most urinary calculi consisted of two components (50.9%), followed by stones of a single constituent (27.1%) and three-component stones (21.9%), while four-component stones were only rarely identified (0.1%). Among all stones, 49.8% consisted of whewellite (COM), weddellite (COD), and mixtures of COM and COD, 33.8% were pure carbonate apatite (CA) and mixtures of CA with COM and/or COD, while 7.6% were composed of uric acid anhydrous (UAA), uric acid dihydrate (UAD), and mixed UAA and UAD. The remaining 8.8% of calculi were rare single-component stones and rare mixtures of various constituents. The number of stone components was inversely associated with age (p < 0.001). The proportion of men decreased significantly with the number of stone constituents, from 3.01:1 for single-component stones to 1.0:1 for four-component urinary calculi (p < 0.001). The vast majority of urinary calculi consisted of two or more components in varying proportions. While age was inversely associated with the number of stone constituents, the proportion of women increased significantly from single-component to four-component urinary calculi. A significant proportion of mixed stones could present a challenge for diagnosis and targeted recurrence prevention.

Ambra1 in exosomes secreted by HK-2 cells damaged by supersaturated oxalate induce mitophagy and autophagy-ferroptosis in normal HK-2 cells to participate in the occurrence of kidney stones

Injury to the renal tubular epithelium has emerged as a leading factor underlying the formation of kidney stones. Indeed, epithelial cell damage contributes to the adherence and aggregation of crystals, thereby accelerating the formation of renal stones. Meanwhile, exosomes play an instrumental role in cellular communication, including DNA, RNA, mRNA, etc. In this study, homogenous cells were treated with exosomes derived from damaged cells in an attempt to establish "positive feedback" of cell damage, and the desired results were achieved. To begin, a serum-free medium and supersaturated concentrations of oxalate were added to the HK-2 cell line, and then exosomes were isolated from the two groups for analysis and comparison, and the autophagy-related gene Ambra1 (autophagy and beclin-1 regulator 1) was detected. Subsequently, normal HK-2 cells were treated with exosomes, and the related indexes of autophagy, ferroptosis and mitophagy were determined. Thereafter, Ambra1 was knocked down in exosome-derived HK-2 cells, resulting in the down-regulation of Ambra1 expression in exosomes produced by HK-2 cells following oxalate intervention. Thereafter, the ability of exosomes to stimulate autophagy, mitophagy and ferroptosis was re-evaluated in HK-2 cells after Ambra1 knockdown. The results corroborated that exosomes secreted by oxalate-treated HK-2 can directly elevate autophagy, ferroptosis and mitophagy levels in normal cells, and this effect was significantly mitigated following Ambra1 knockdown within exosomes. Meanwhile, exosomes-induced autophagy and ferroptosis were alleviated after knockdown of beclin-1 in recipient HK-2 cells. These results further suggest that beclin-1 plays a critical role in the process of exosome-induced autophagy-ferroptosis.

A novel in vivo model of ureteral fibrosis induced by calcium oxalate beads in C57BL/6J mice

The global incidence of ureteroliths in humans is increasing, particularly posing a problem in developed countries. The most common stone type is calcium oxalate, which is associated with a high recurrence rate. In veterinary medicine, stones are the most common cause of ureteral obstruction in cats, accounting for 72-87% of cases. In cats, stones cause irreversible ureteral damage, necessitating stone treatment as well as ureteral therapy. However, the mechanisms underlying the ureteral damage caused by stones remain unclear. Therefore, this study aimed to create a mouse model suitable for studying the ureteral fibrosis caused by oxalate stones by artificially embedding calcium oxalate in the ureter. Pathological tissue analysis was used to compare normal ureters without ligation and ureters with sham or oxalate bead implantation. The ureters of the sham and oxalate bead groups showed granulation tissue formation, transitional epithelium exfoliation, and densely packed connective tissue in the proprietary and muscle layer regions. Particularly in the oxalate bead group, infiltration of degenerated neutrophils, presence of foreign body giant cells, and hyperplasia of the transitional epithelium were observed. The proportion of fibrosis was higher in the oxalate group than in the sham group. Overall, this mouse model created using oxalate bead implantation has the potential to efficiently induce ureteral obstruction. This mouse model is expected to be used for elucidating the molecular mechanisms of ureteral fibrosis and evaluating therapeutic drugs in future.

Retrospective analysis of urinary tract stone composition in a Chinese ethnic minority colony based on Fourier transform infrared spectroscopy

To analyze the relationship between the composition of urinary stones and various influencing factors in the Enshi region. We used FT-IR to examine the composition of 1092 stone samples. Combined with the relevant clinical materials, the data were analyzed using both one-dimensional statistical methods and multivariate statistical methods. The study included 1092 stone samples, classified as follows: 457 (41.8%) with a single component, 453 (41.5%) with two components, 149 (13.6%) with three components, and 33 (3.0%) with four components. Stones were categorized into five types: Calcium Oxalate (CaOx) (76.4%), carbapatite (CaP) (9.3%), Struvite (ST) (8.3%), Uric Acid (UA) (4.9%), and Others (1.0%). Age, gender, urinary tract infection (UTI), family history of urinary stones (FH), hyperuricemia (HUA) and stone location were significantly associated with stone type. Logistic regression revealed that females and UTI were relative risk factors for predicting CaP and ST, while FH and HUA were relative risk factors for predicting UA. Our study indicates that the overall composition of urinary tract stones in the Enshi region is consistent with that of the entire China. Additionally, the predisposing factors for stone formation vary in terms of gender, age, FH, UTI, hyperuricemia HUA, and stone location.

Corn Silk Polysaccharides with Different Carboxyl Contents Reduce the Oxidative Damage of Renal Epithelial Cells by Inhibiting Endocytosis of Nano-calcium Oxalate Crystals

OBJECTIVE

Renal epithelial cell injury and cell-crystal interaction are closely related to kidney stone formation.

METHODS

This study aims to explore the inhibition of endocytosis of nano-sized calcium oxalate monohydrate (nano-COM) crystals and the cell protection of corn silk polysaccharides (CCSPs) with different carboxyl contents (3.92, 7.75, 12.90, and 16.38%). The nano-COM crystals protected or unprotected by CCSPs were co-cultured with human renal proximal tubular epithelial cells (HK-2), and then the changes in the endocytosis of nano-COM and cell biochemical indicators were detected.

RESULTS

CCSPs could inhibit the endocytosis of nano-COM by HK-2 cells and reduce the accumulation of nano-COM in the cells. Under the protection of CCSPs, cell morphology is restored, intracellular superoxide dismutase levels are increased, lipid peroxidation product malondialdehyde release is decreased, and mitochondrial membrane potential and lysosomal integrity are increased. The release of Ca²⁺ ions in the cell, the level of cell autophagy, and the rate of cell apoptosis and necrosis are also reduced. CCSPs with higher carboxyl content have better cell protection abilities.

CONCLUSION

CCSPs could inhibit the endocytosis of nano-COM crystals and reduce cell oxidative damage. CCSP3, with the highest carboxyl content, shows the best biological activity.

The altered composition of gut microbiota and biochemical features as well as dietary patterns in a southern Chinese population with recurrent renal calcium oxalate stones

The correlation among gut microbiota, biochemical features, and dietary patterns in recurrent stone formers has been inadequately investigated in the Chinese population. Forty-two patients with calcium oxalate stones (CaOxS group), including 34 recurrent stone formers (RS group), and 40 nonstone healthy subjects (NS group) from Changshu Hospital Affiliated with Soochow University, were prospectively recruited. Food frequency questionnaires were completed by participants, fasting vein blood was extracted, 24-h urine was collected for biochemical detection, and fecal samples were gathered for 16S ribosomal RNA (rRNA) gene sequencing. BMI; serum levels of triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), magnesium, and creatinine; and urine levels of magnesium in stone formers were significantly different from those of controls, and RS patients showed significantly low serum phosphate and high urine phosphate levels. Celery, bamboo shoots, and pickled food were the favored foods of local stone formers. Patients with recurrent stones had altered microbiota composition, with Escherichia, Fusobacterium, and Epulopiscium being the predominant pathogenic genera. The gut microbiota in RS patients had stronger functions in fatty acid and amino acid degradation but weaker functions in their biosynthesis. The pathogenic genera were positively correlated with BMI; serum levels of TGs and creatinine; urine levels of calcium, phosphate, and uric acid (UA); and celery, bamboo shoots, and pickled food intake. The abundance of Escherichia and Fusobacterium and the levels of serum magnesium and creatinine were the most relevant factors associated with stone recurrence and could be validated as biomarkers of recurrence. Our research provides a novel prevention strategy for the recurrence of renal calcium oxalate stones in the Han Chinese population of southern China.

Autofluorescence spectral analysis for detecting urinary stone composition in emulated intraoperative ambient

The prevalence and disease burden of urolithiasis has increased substantially worldwide in the last decade, and intraluminal holmium laser lithotripsy has become the primary treatment method. However, inappropriate laser energy settings increase the risk of perioperative complications, largely due to the lack of intraoperative information on the stone composition, which determines the stone melting point. To address this issue, we developed a fiber-based fluorescence spectrometry method that detects and classifies the autofluorescence spectral fingerprints of urinary stones into three categories: calcium oxalate, uric acid, and struvite. By applying the support vector machine (SVM), the prediction accuracy achieved 90.28 % and 96.70% for classifying calcium stones versus non-calcium stones and uric acid versus struvite, respectively. High accuracy and specificity were achieved for a wide range of working distances and angles between the fiber tip and stone surface in an emulated intraoperative ambient. Our work establishes the methodological basis for engineering a clinical device that achieves real-time, in situ classification of urinary stones for optimizing the laser ablation parameters and reducing perioperative complications in lithotripsy.

Integrated single-nucleus sequencing and spatial architecture analysis identified distinct injured-proximal tubular types in calculi rats

BACKGROUND

Urolithiasis with high prevalence and recurrence rate, has impacts on kidney injury in patients, becomes a socioeconomic and healthcare problem in worldwide. However, the biology of kidney with crystal formation and proximal tubular injury remains essentially unclear. The present study aims to evaluate the cell biology and immune-communications in urolithiasis mediated kidney injury, to provide new insights in the kidney stone treatment and prevention.

RESULTS

We identified 3 distinct injured-proximal tubular cell types based on the differentially expression injury markers (Havcr1 and lcn2) and functional solute carriers (slc34a3, slc22a8, slc38a3 and slc7a13), and characterized 4 main immune cell types in kidney and one undefined cell population, where F13a1^+/high/CD163^+/high monocyte & macrophage and Sirpa/Fcgr1a/Fcgr2a^+/high granulocyte were the most enriched. We performed intercellular crosstalk analysis based on the snRNA-seq data and explored the potential immunomodulation of calculi stone formation, and founded that the interaction between ligand Gas6 and its receptors (Gas6-Axl, Gas6-Mertk) was specifically observed in the injured-PT1 cells, but not injured-PT2 and -PT3 cells. The interaction of Ptn-Plxnb2 was only observed between the injured-PT3 cells and its receptor enriched cells.

CONCLUSIONS

Present study comprehensively characterized the gene expression profile in the calculi rat kidney at single nucleus level, identified novel marker genes for all cell types of rat kidney, and determined 3 distinct sub-population of injured-PT clusters, as well as intercellular communication between injured-PTs and immune cells. Our collection of data provides a reliable resource and reference for studies on renal cell biology and kidney disease.

Rectal prolapse in a 30-year-old bladder stone male patient: A case report

BACKGROUND

Rectal prolapse occurs most commonly in children and middle-aged and elderly women and is relatively rare in young men and is occasionally caused by bladder stones. Severe rectal prolapse, bilateral hydronephrosis, and renal insufficiency caused by bladder stones are rare in a 30-year-old man.

CASE SUMMARY

We report the case of a 30-year-old male patient with cerebral palsy who presented with a large bladder stone that resulted in severe rectal prolapse, bilateral hydronephrosis, and renal insufficiency. Following a definitive diagnosis, the bladder stone was successfully removed, and his kidney function returned to normal. We assessed the patient’s nutritional status and stone composition and concluded that the main cause was malnutrition.

CONCLUSION

Rectal prolapse is a rare clinical manifestation of bladder stones, particularly in young adults. Cerebral palsy patients are a vulnerable group in society because of their intellectual disabilities and communicative impairments. Accordingly, besides taking care of their daily diet, abnormal signs in their bodies should receive the doctors’ attention in a timely manner.

The relationship between patients' kidney stone type and demographics in Israel: analysis of 10 K patients

PURPOSE

To analyze urinary stone composition in Israel and assess the effects of key demographic parameters (gender, age, socioeconomic status, ethnicity, medical history and geographic region) on stone composition.

METHODS

A retrospective review was conducted of stone analysis of 10,633 patients from an HMO Israeli database analyzed by a central laboratory from 2014 to 2019 and subjected to Fourier-transform infrared spectroscopy. Associations between stone composition and different demographic parameters were determined using the Chi-square test.

RESULTS

Calcium oxalate (CaOx) monohydrate accounted for 51.9% of the stones. Of the total sample, 5776 stones had one single component (54%), whereas 4857 (46%) had mixed components. Men had a higher frequency of CaOx stones (89.6% vs. 85.6%), whereas women had a higher frequency of calcium phosphate, infection, and cystine stones (27.2%, 17.7%, and 0.9% vs. 17.2%, 7.5%, and 0.5%, respectively). Cystine stones were more abundant in Arabs (1.2% vs. 0.5% in the Jewish population). Lower socioeconomic status was associated with a higher prevalence of calcium phosphate, uric acid, and infection stones and a lower prevalence of CaOx stones. Uric acid stones were associated with medical conditions such as diabetes, hypertension, ischemic heart disease, and obesity (28.3%, 24.9%, 25.7%, and 22.6% vs. 9.6%, 8.4%, 12.3%, and 10.3%, respectively).

CONCLUSIONS

Stone types were highly influenced by patients' demographics. COM was the most common stone component in either pure or complex form. UA stone prevalence was found to increase with age and was associated with medical conditions such as diabetes, hypertension, ischemic heart disease, and obesity.

Metabolic changes in kidney stone disease

Kidney stone disease (KSD) is one of the earliest medical diseases known, but the mechanism of its formation and metabolic changes remain unclear. The formation of kidney stones is a extensive and complicated process, which is regulated by metabolic changes in various substances. In this manuscript, we summarized the progress of research on metabolic changes in kidney stone disease and discuss the valuable role of some new potential targets. We reviewed the influence of metabolism of some common substances on stone formation, such as the regulation of oxalate, the release of reactive oxygen species (ROS), macrophage polarization, the levels of hormones, and the alternation of other substances. New insights into changes in substance metabolism changes in kidney stone disease, as well as emerging research techniques, will provide new directions in the treatment of stones. Reviewing the great progress that has been made in this field will help to improve the understanding by urologists, nephrologists, and health care providers of the metabolic changes in kidney stone disease, and contribute to explore new metabolic targets for clinical therapy.

Causal association of genetically predicted urinary sodium-potassium ratio and upper urinary calculi

The causality between the urinary sodium-potassium ratio and upper urinary calculi has not been clarified and easily affected by confounders. We performed two-sample and multivariable Mendelian randomization (MR) analysis to evaluate the potential causal role of the urinary sodium-potassium ratio in upper urinary calculi. Data of the urinary sodium-potassium ratio (N = 326,938), upper urinary calculi (N = 337,199), and confounding factors including BMI (N = 336,107), ever-smoke (N = 461,066), hypertension (N = 218,754), diabetes (N = 218,792), and alcohol intake frequency (N = 462,346) were obtained from the IEU OpenGWAS Project database. The inverse-variance weighted (IVW), weighted median, and MR-Egger methods were used to estimate MR effects. The MR-Egger intercept test, Cochran's Q test, MR-PRESSO, leave-one-out method, and funnel plot were used for sensitivity analysis. A causal relationship was found between the urinary sodium-potassium ratio and upper urinary calculi (OR = 1.008, 95% CI = 1.002-1.013, P = 0.011). FinnGen data supported this conclusion (OR = 2.864, 95% CI = 1.235-6.641, P = 0.014). The multivariable Mendelian randomization analysis result showed that after adjusting for the effects of five confounders, the urinary sodium-potassium ratio was still positively correlated with upper urinary calculi (OR = 1.005, 95% CI = 1.001-1.009, P = 0.012). This study demonstrated a positive causal association between the urinary sodium-potassium ratio and upper urinary calculi using MR analysis. Timely identification of changes in urine composition and dietary regulation of sodium and potassium intake could greatly reduce the incidence of future urinary calculi.

Machine learning based multi-label classification of single or mixed-composition urinary stones in in vivo spectral CT

BACKGROUND

Urinary stones comprise both single and mixed compositions. Knowledge of the stone composition helps the urologists choose appropriate medical interventions for patients. The parameters from the spectral computerized tomography (CT) analysis have potential values for identification of the urinary stone compositions.

PURPOSE

The present study aims to identify the compositions of urinary stones in vivo using parameters from spectral CT and machine learning, based on multi-label classification modeling.

METHODS

This retrospective study collected 252 urinary stone samples with single/mixed compositions (including carbapatite [CP], calcium oxalate monohydrate [COM], calcium oxalate dehydrate [COD], uric acid [UA], and struvite [STR]), which were confirmed by ex vivo infrared spectroscopy. Parameters were extracted from an energy spectrum analysis (ESA) of the spectral CT, including the effective atomic number (Z_eff ), Z_eff histogram, CT values at a given x-ray energy level, and material densities. These ESA parameters were utilized for composition analysis via a multi-label classification fusion framework, where 250 multi-label models were built and the classification decisions from the top performance models were integrated by a multi-criterion weighted fusion (MCWF) approach in order to reach a consensus prediction. An example-based metric A c c e x a m $Ac{c_{exam}}$ and label-based metric A c c l a b e l $Ac{c_{label}}$ were used for global and label-wise accuracy evaluations, respectively. The top-ranked parameters associated with discriminating the stone composition were also identified.

RESULTS

The multi-label classification fusion framework achieved an overall A c c e x a m $Ac{c_{exam}}$ of 81.2%, with A c c l a b e l $Ac{c_{label}}$ of 86.7% (CP), 90.6% (COM), 80.6% (COD), 95.0% (UA), and 94.4% (STR) for each composition on the independent testing cohort 1, and A c c e x a m $Ac{c_{exam}}$ of 76.4% with A c c l a b e l $Ac{c_{label}}$ of 80.5% (CP), 88.7% (COM), 74.9% (COD), 94.4% (UA), and 98.5% (STR) on the independent testing cohort 2.

CONCLUSION

The parameters extracted from the ESA on spectral CT can be utilized to characterize single or mixed stone compositions via multi-label classification modeling. The generalization capability of the proposed methodology still requires further verification.

Acute kidney injury increases risk of kidney stones-a retrospective propensity score matched cohort study

BACKGROUND

Acute kidney injury (AKI) is common. An episode of AKI may modify the risk of developing kidney stones by potential long-term effects on urine composition. We aimed to investigate the association between AKI and the risk of kidney stone presentations.

METHODS

The retrospective cohort study used patient data (1 January 2008-31 December 2017), from an Australian Local Health District, which included AKI diagnosis, demographics, comorbidities and kidney stone admissions. Time-varying Cox proportional hazards and propensity-matched analysis were used to determine the impact of AKI on the risk of kidney stones. To address possible population inhomogeneity in comparisons between no AKI and hospitalized AKI, sub-group analysis was done comparing inpatient and outpatient AKI versus no AKI, to assess consistency of association with future stones. Sensitivity analysis was undertaken to capture the impact of a known AKI status and AKI severity.

RESULTS

Out of 137 635 patients, 23 001 (17%) had an AKI diagnosis and 2295 (2%) had kidney stone presentations. In the unadjusted analysis, AKI was associated with kidney stones, with AKI used as a time-varying exposure, [hazard ratio (HR) 1.32, 95% confidence interval (CI) 1.16-1.50)]. Both inpatient-AKI (HR 1.19, 95% CI 1.01-1.39) and outpatient-AKI (HR 1.59, 95% CI 1.30-1.94) were significantly associated with future stones compared to no AKI subjects. This association persisted in the adjusted analysis (HR 1.45, 95% CI 1.26-1.66), propensity-matched dataset (HR 1.67, 95% CI 1.40-1.99) and sensitivity analysis. There was a dose-response relationship with higher stages of AKI being associated with a greater risk of kidney stones.

CONCLUSIONS

In a large cohort of patients, AKI is associated with a greater risk of kidney stones, which increases with higher stages of AKI. This association should be examined in other cohorts and populations for verification.

Application of metabolomics in urolithiasis: the discovery and usage of succinate

Urinary stone is conceptualized as a chronic metabolic disorder punctuated by symptomatic stone events. It has been shown that the occurrence of calcium oxalate monohydrate (COM) during stone formation is regulated by crystal growth modifiers. Although crystallization inhibitors have been recognized as a therapeutic modality for decades, limited progress has been made in the discovery of effective modifiers to intervene with stone disease. In this study, we have used metabolomics technologies, a powerful approach to identify biomarkers by screening the urine components of the dynamic progression in a bladder stone model. By in-depth mining and analysis of metabolomics data, we have screened five differential metabolites. Through density functional theory studies and bulk crystallization, we found that three of them (salicyluric, gentisic acid and succinate) could effectively inhibit nucleation in vitro. We thereby assessed the impact of the inhibitors with an EG-induced rat model for kidney stones. Notably, succinate, a key player in the tricarboxylic acid cycle, could decrease kidney calcium deposition and injury in the model. Transcriptomic analysis further showed that the protective effect of succinate was mainly through anti-inflammation, inhibition of cell adhesion and osteogenic differentiation. These findings indicated that succinate may provide a new therapeutic option for urinary stones.

High ASA Physical Status and Low Serum Uric Acid to Creatinine Ratio are Independent Risk Factors for Postoperative Delirium Among Older Adults Undergoing Urinary Calculi Surgery

Purpose

This study was to investigate the incidence and potential predictive factors for postoperative delirium (POD) in older people following urinary calculi surgery, and to establish the corresponding risk stratification score by the significant factors to predict the risk of POD.

Patients and Methods

We retrospectively analyzed the perioperative data of 195 patients aged 65 or older who underwent elective urinary calculi surgery between September 2020 and September 2022. POD was defined by chart-based method, and the serum uric acid to creatinine (SUA/Cr) ratio as well as neutrophil-to-lymphocyte ratio (NLR) were calculated, respectively. Identification of the risk factors for POD was performed by univariate and multivariate logistic regression analysis. Moreover, the risk stratification score was developed based on the regression coefficients of the associated variables.

Results

In 195 eligible patients following urinary calculi surgery, the median age was 69 (66-72) and 19 patients ultimately developed POD (9.7%). The results by univariate analysis showed that patients with advanced age, high American Society of Anesthesiologists (ASA) physical status (≥3) and low SUA/Cr ratio (≤3.3) were more likely to develop POD, but dexmedetomidine can significantly decrease the risk of the occurrence of POD. The multivariate analysis further indicated that high ASA physical status (≥3) and low SUA/Cr ratio (≤3.3) were independently associated with POD, and the POD incidence could obviously be elevated with the increase of risk stratification score. Moreover, patients with delirium had longer hospital stays.

Conclusion

POD is frequent in geriatric patients following urinary calculi surgery (9.7%). The high ASA physical status (≥3) and low SUA/Cr ratio (≤3.3) were effective predictors of POD. The corresponding risk stratification based on these factors could be beneficial to determining patients who are susceptible to POD, and thus better preventing and reducing the occurrence of POD. However, large prospective studies are needed to confirm this finding.

Spectrum of Bacterial Pathogens from Urinary Infections Associated with Struvite and Metabolic Stones

OBJECTIVE

The purposes of this multi-center study were to evaluate the rate of infection stones and to evaluate the urine cultures of patients with infection stones.

MATERIALS

Charts of adulpatients with urinary stones were reviewed and data on stone analyses and urine cultures were collected.

RESULTS

In total, 1204 renal stone formers (RSFs) from 10 countries were included (776 males, 428 females). Fifty-six patients (4.6%) had struvite stones. The highest frequency of struvite stones was observed in India (23%) and Pakistan (18%). Lower rates were reported in Canada (2%), China (3%), Argentina (3%), Iraq (3%), Italy (3.5%) and Poland (3%), and intermediate rates in Egypt (5.5%) and Bulgaria (5.4%). Urine cultures were retrieved from 508 patients. Patients with struvite stones had a positive culture in 64.3% of the samples and patients with other stones, in 26.7%. In struvite stones, the most common isolates were Escherichia coli (27.7%) and Proteus spp. (27.7%), followed by Klebsiella spp. (16.7%); in other types of stone, it was Escherichia coli (47.6%), followed by Gram-positive bacteria (14.0%) Conclusions: The struvite stone composition was associated with a urinary infection, although an infection was not demonstrable with a conventional midstream urine culture in about 30%.

Osteopontin: An important protein in the formation of kidney stones

The incidence of kidney stones averages 10%, and the recurrence rate of kidney stones is approximately 10% at 1 year, 35% at 5 years, 50% at 10 years, and 75% at 20 years. However, there is currently a lack of good medicines for the prevention and treatment of kidney stones. Osteopontin (OPN) is an important protein in kidney stone formation, but its role is controversial, with some studies suggesting that it inhibits stone formation, while other studies suggest that it can promote stone formation. OPN is a highly phosphorylated protein, and with the deepening of research, there is growing evidence that it promotes stone formation, and the phosphorylated protein is believed to have adhesion effect, promote stone aggregation and nucleation. In addition, OPN is closely related to immune cell infiltration, such as OPN as a pro-inflammatory factor, which can activate mast cells (degranulate to release various inflammatory factors), macrophages (differentiated into M1 macrophages), and T cells (differentiated into T1 cells) etc., and these inflammatory cells play a role in kidney damage and stone formation. In short, OPN mainly exists in the phosphorylated form in kidney stones, plays an important role in the formation of stones, and may be an important target for drug therapy of kidney stones.

The effect of metabolic risk factors on urinary stone composition: An observational study

To investigate how the risk factors of metabolic diseases affect urinary stone composition, particularly uric acid (UA) stones. Overall, 583 patients with data on urinary stone composition were retrospectively analyzed and classified into UA and nonUA stone formers according to the presence of the UA component. Various factors were compared between both groups. Participants were categorized according to age, glucose level, HbA1c level, and estimated glomerular filtration rate (eGFR) into subgroups, and the incidence of UA stone was compared. Overall, 137 UA stone formers (23.5%) and 446 nonUA stone formers (76.5%) were included. Mean age and male-to-female ratio were higher in the UA group than in the nonUA group. The rates of diabetes mellitus (DM), hypertension, chronic kidney disease, and coronary artery disease, all of which were associated with differences in urinary stone composition, were higher in the UA group than in the nonUA group. The UA group exhibited lower mean eGFR and higher glucose and HbA1c levels. Similarly, the UA group had higher mean UA levels and predictably lower urinary pH. In subgroup analysis, higher age, glucose level, HbA1c level, and lower eGFR were associated with an increased risk of UA stone formation. In the multivariate logistic regression analysis, the UA group showed a significantly higher age (P < .001), DM frequency (P = .049), and HbA1c level (P = .032), but significantly lower eGFR than the nonUA group (P < .001). Age and DM were independent risk factors for UA urolithiasis, implying a relationship between urinary stone composition and metabolic diseases. Additionally, renal function and HbA1c level were risk factors for UA stones.

Carriage prevalence of Neisseria meningitidis in China, 2005-2022: a systematic review and meta-analysis

INTRODUCTION

Neisseria meningitidis (Nm) is a major cause of meningitis and septicemia. Most people are infected with latent infections or are carriers. We aimed to estimate the carriage prevalence of Nm in China.

METHODS

We did a systematic review of published work to assess the prevalence of meningococcal carriage in China. The quality assessment was conducted by the risk of bias tool according to Damian Hoy's study. We estimated pooled proportions of carriage and its 95% confidence interval (95% CI) using fixed effect model for studies with low heterogeneity and random effect model for studies with moderate or high heterogeneity. Subgroup analyses were also conducted by region and age group.

RESULTS

In total, 115 studies were included. The quality evaluation grades of all included documents were medium or high grade. The weighted proportion of carriage was 2.86% (95% CI: 2.25-3.47%, I2: 97.7%, p = 0). The carriage prevalence of Nm varied between provinces, ranged from 0.00% (95% CI: 0.00-0.66%) to 15.50% (95% CI: 14.01-16.99%). Persons aged 15 years and older had the highest carriage 4.38% (95% CI: 3.15-5.62%, I2: 95.4%, p < 0.0001), and children under 6 years of age had the lowest carriage 1.01% (95% CI: 0.59-1.43%, I2: 74.4%, p < 0.0001). In positive carriers, serogroup B (41.62%, 95% CI: 35.25-48.00%, I2: 98.6%, p = 0) took up the highest proportion, and serogroup X (0.02%, 95% CI: 0.00-0.09%, I2: 0.00%, p = 1) accounted for the lowest proportion.

CONCLUSION

The meningococcal carriage in China was estimated low and varied by region and age group. Understanding the epidemiology and transmission dynamics of meningococcal infection in insidious spreaders is essential for optimizing the meningococcal immunization strategies of the country.

Prevalence and trends of urolithiasis among adults

PURPOSE OF REVIEW

The purpose of this article is to review and synthesize the current literature on the epidemiology of urolithiasis.

RECENT FINDINGS

The global patterns of urolithiasis are changing, as the prevalence of urolithiasis appears to be increasing across the world. Geographical variation in the prevalence of urolithiasis is noted across countries and within each country. Although urolithiasis is more common among men and white race, recent data suggests a more prominent rise in the prevalence among women and African Americans. Yet, no conclusive explanations for these phenomena are reported so far.

SUMMARY

Urolithiasis is a highly prevalent condition with an increasing prevalence among women as compared with men closing the gender gap in urolithiasis. Further studies are needed to identify the potential causes for this observation.

Giant bladder stone: A case report

Giant bladder stones are rare in younger patients. Herein, we report a case of acute renal failure in a 31-year-old male with a giant bladder stone. The patient presented with lower urinary tract symptoms and urinary retention with milky-white urine. An emergency suprapubic cystotomy was performed and an 11-cm oval, solid stone was removed. Post-operative creatinine levels progressively decreased to normal and the patient exhibited smooth urination and good recovery at follow-up. A comprehensive physical examination and thorough investigation of the patient's medical history are required during clinical evaluation, diagnosis and treatment, thus preventing misdiagnoses and ensuring prompt treatment.

Chronic hepatitis B virus infection increases the risk of upper urinary calculi

Background

Although hepatitis B virus (HBV) is a recognized risk factor for renal diseases, little is known about HBV infection in individuals with upper urinary calculi (UUC). We investigated the relationship between chronic HBV infection and UUC.

Methods

We retrospectively analysed data from 1399 patients who were discharged from the Department of Urology (2017–2018). The diagnosis of UUC was determined using urinary tract ultrasonography or computed tomography, and HBV infection was evaluated by a positive hepatitis B surface antigen (HBsAg) test. Data on patients with and without UUC and HBsAg-positive and HBsAg-negative patients were compared by univariate and multivariate analyses.

Results

Data on chronic HBV infection and UUC were available for 1062 patients, including 514 who presented with UUC and 548 who did not. Overall, 5.8% of total patients, 8.0% of UUC patients and 3.8% of non-UUC patients had chronic HBV infection. UUC patients (41/514) had a significantly higher prevalence of HBsAg positivity (OR 2.175; 95% CI 1.267–3.734; P = 0.004) than non-UUC patients (21/548). After stratifying by sex, the relative odds of HBsAg positivity were statistically significant in men (OR 2.156; 95% CI 1.162–4.003; P = 0.015) but not in women (OR 2.947; 95% CI 0.816–10.643; P = 0.099). The incidence of urinary pH > 6 and staghorn stones was significantly higher in HBsAg-positive UUC patients than in HBsAg-negative UUC patients.

Conclusion

This is the first study to demonstrate that chronic HBV infection is strongly associated with UUC, at least in men. The urinary pH > 6 and staghorn stones were more common in UUC patients with chronic HBV infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-01038-z.

Influence of Age and Geography on Chemical Composition of 98043 Urinary Stones from the USA

Background

Urolithiasis is a growing issue globally, but it is heterogeneous, with a different epidemiology and pathophysiology for each different stone composition.

Objective

The purpose of this study is to describe the incidence of urinary stones in the USA from 2016 to 2019 by chemical composition and to investigate the influence of age and geography on these stone types.

Design, setting, and participants

We obtained compositional analyses for all urinary stones submitted to a national laboratory over an approximately 3-yr period.

Outcome measurements and statistical analysis

Data collected included the chemical constituents of a stone, patient age, and geographical origin. We describe the incidence of each stone type by frequency. Statistical testing was performed to determine the influence of age and geographical region on overall incidence of each stone composition.

Results and limitations

In total, 99 908 specimens were analyzed. When pure stones were ordered by frequency, we found that the most common stone type was calcium oxalate (CaOx) (79.2%), followed by uric acid (UA; 14.3%), calcium phosphate (CaPO₄; 3.7%), cystine (0.51%), drug induced (0.12%), and magnesium ammonium phosphate (0.04%). CaOx, UA, and CaPO₄ were often mixed with one another. Among CaOx stones, the plurality (28.0%) was made of pure calcium oxalate monohydrate (COM), and only 0.002% was pure calcium oxalate dihydrate. There was an overall association between stone composition and both geographical distribution and age (p < 0.001).

Conclusions

CaOx stones comprise the majority of urinary stones in the USA, of which almost 28% were pure COM. Additionally, age and geographical region are significantly associated with variations in stone composition.

Patient summary

We evaluated the incidence of urinary stones in the USA based on their chemical composition. The most common stone type was calcium oxalate, the majority of which was pure calcium oxalate monohydrate. We also found age and geographical region to be significantly associated with variations in stone composition.

The characteristics and influencing factors of fever in postoperative patients undergoing percutaneous nephrolithotomy: A retrospective analysis

Percutaneous nephrolithotomy (PCNL) is commonly used for the treatment of upper urinary calculi in clinical setting, and fever is a common complication after PCNL. It is necessary to evaluate the risk factors of fever in patients undergoing PCNL, to provide insights into the management of PCNL.Patients who underwent PCNL in our hospital from January 2018 to August 2020 were included. The clinical data of postoperative fever and no fever patients were collected and assessed. Logistic regression analyses were conducted to analyze the risk factors for fever in patients undergoing PCNL.A total of 276 patients undergoing PCNL were included, the incidence of postoperative fever for patients undergoing PCNL was 19.39%. No significant differences in the gender, body mass index, alcohol drinking, smoking, hypertension, hyperlipidemia, intraoperative blood infusion, length of hospital stay between fever patients, and no fever patients were found (all P > .05). There were significant differences in the age, diabetes, size of stones, duration of surgery between fever patients, and no fever patients (all P < .05). Age ≥60 years (odds ratio [OR] 2.143, 95% confidence interval [CI] 1.101∼3.264), diabetes (OR 2.218, 95% CI 1.176∼4.642), size of stone ≥2 cm (OR 1.428, 95%CI 1.104∼2.055), duration of surgery ≥100 minutes (OR 1.334, 95% CI 1.015∼1.923) were the risk factors for fever in patients with PCNL (all P < .05). Escherichia coli (48.44%), Staphylococcus aureus (18.75%), and Candida albicans (10.93%) were the top 3 pathogenic bacteria of urine culture.Fever is one of the common complications after PCNL. Patients with high-risk factors should be given full attentions and take corresponding preventive measures targeted on risks.

Kidney stone proteomics: an update and perspectives

INTRODUCTION

Main problems of kidney stone disease are its increasing prevalence and high recurrence rate after calculi removal in almost all areas around the globe. Despite enormous efforts in the past, its pathogenic mechanisms remain unclear and need further elucidations. Proteomics has thus become an essential tool to unravel such sophisticated disease mechanisms at cellular, subcellular, molecular, tissue, and whole organism levels.

AREAS COVERED

This review provides abrief overview of kidney stone disease followed by updates on proteomics for investigating urinary stone modulators, matrix proteins, cellular responses to different types/doses of calcium oxalate (CaOx) crystals, sex hormones and other stimuli, crystal-cell interactions, crystal receptors, secretome, and extracellular vesicles (EVs), all of which lead to better understanding of the disease mechanisms. Finally, the future challenges and translation of these obtained data to the clinic are discussed.

EXPERT OPINION

Knowledge from urinary proteomics for exploring the important stone modulators (either inhibitors or promoters) will be helpful for early detection of asymptomatic cases for prompt prevention of symptoms, complications, and new stone formation. Moreover, these modulators may serve as the new therapeutic targets in the future for successful treatment and prevention of kidney stone disease by medications or other means of intervention.

Recent advances on the mechanisms of kidney stone formation (Review)

Kidney stone disease is one of the oldest diseases known to medicine; however, the mechanisms of stone formation and development remain largely unclear. Over the past decades, a variety of theories and strategies have been developed and utilized in the surgical management of kidney stones, as a result of recent technological advances. Observations from the authors and other research groups suggest that there are five entirely different main mechanisms for kidney stone formation. Urinary supersaturation and crystallization are the driving force for intrarenal crystal precipitation. Randall's plaques are recognized as the origin of calcium oxalate stone formation. Sex hormones may be key players in the development of nephrolithiasis and may thus be potential targets for new drugs to suppress kidney stone formation. The microbiome, including urease-producing bacteria, nanobacteria and intestinal microbiota, is likely to have a profound effect on urological health, both positive and negative, owing to its metabolic output and other contributions. Lastly, the immune response, and particularly macrophage differentiation, play crucial roles in renal calcium oxalate crystal formation. In the present study, the current knowledge for each of these five aspects of kidney stone formation is reviewed. This knowledge may be used to explore novel research opportunities and improve the understanding of the initiation and development of kidney stones for urologists, nephrologists and primary care.

Epidemiological and clinical characteristics of stone composition: a single-center retrospective study

The aim of the study was to investigate the epidemiological characteristics of stone components in patients with urolithiasis and analyze the associations between stone components with patients' clinical characteristics. A total of 7126 patients with urolithiasis between July 2005 and June 2020 were retrospectively analyzed. In this research, calcium oxalate stones (74.6%) accounted for the highest proportion, followed by infection stones (11.8%), uric acid (10.6%), brushite (2.0%), and others (1.1%). The change in trend in the composition of urinary stones revealed that the proportion of uric acid declined steadily, while the content of infection stones increased gradually over 15 years. The results also suggested that stone composition was significantly associated with PM2.5, gender, age, BMI, diabetes, hypertension, CCVD, alcohol consumption, albumin, creatinine, WBCHP, leukocyte, urine pH, nitrite and urine culture (P < 0.05). However, there was no significant correlation between stone composition with smoking, WBC and NEU% (P > 0.05). Our study concluded that calcium oxalate represented the highest proportion, followed by infection stones, uric acid, brushite, and others. The proportion of uric acid declined steadily, while the infection stones increased gradually. Furthermore, the factors influencing the formation of urinary calculi are PM2.5, gender, age, BMI, diabetes, hypertension, CCVD, alcohol consumption, albumin, creatinine, WBCHP, leukocyte, urine pH, nitrite and urine culture. Collectively, these results may provide clues to establish effective prevention and management strategies for urinary calculi.

Urinary stone composition analysis and clinical characterization of 1520 patients in central China

A total of 1520 patients with urinary stones from central China were collected and analysed by Fourier transform infrared spectroscopy between October 1, 2016 and December 31, 2019. For all patients, age, sex, comorbidities, stone location, laboratory examination and geographic region were collected. The most common stone component was calcium oxalate (77.5%), followed by calcium phosphate (8.7%), infection stone (7.6%), uric acid (UA) stone (5.3%)and cystine (0.9%). The males had more calcium oxalate stones (p < 0.001), while infection stone and cystine stones occurred more frequently in females (p < 0.001). The prevalence peak occurred at 41-60 years in both men and women. UA stones occurred frequently in patients with lower urinary pH (p < 0.001), while neutral urine or alkaline urine (p < 0.001) and urinary infection (p < 0.001) were more likely to be associated with infection stone stones. Patients with high levels of serum creatinine were more likely to develop UA stones (p < 0.001). The proportion of UA stones in diabetics was higher (p < 0.001), and the incidence of hypertension was higher in patients with UA stones (p < 0.001). Compared to the other types, more calcium oxalate stones were detected in the kidneys and ureters (p < 0.001), whereas struvite stones were more frequently observed in the lower urinary tract (p = 0.001). There was no significant difference in stone composition across the Qinling-Huaihe line in central China except UA stones, which were more frequently observed in patients south of the line (p < 0.001).

Revolution spectral CT for urinary stone with a single/mixed composition in vivo: a large sample analysis

PURPOSE

To analyze various compositions of urinary stones using revolution spectral CT (rapid kV switching dual-energy CT) in vivo.

METHODS

202 patients with urinary stones underwent spectral CT before surgery. Zeff peak, overall scope and CT values were detected. Moreover, water/iodine attenuating material images were obtained. Removed stones were subjected to infrared spectroscopy after surgery. The results of infrared spectroscopy were compared with CT.

RESULTS

28 stones (14.08%) with single composition, 165 stones with two mixed compositions (81.68%), and 9 stones with three mixed compositions (4.46%) were observed. When Zeff peaks of stones with single/mixed compositions were summarized together, 146 peaks of calcium oxalate monohydrate, 119 peaks of calcium oxalate dihydrate, 55 peaks of carbapatite, 38 peaks of urate, 16 peaks of struvite, and 11 peaks of brushite were totally observed. 93.8% of calcium oxalate monohydrate had Zeff peaks between 13.3 and 14.0. 91.6% of calcium oxalate dihydrate had peaks between 12.0 and 13.3. For carbapatite, 90.9% of stones had peaks from 14.0 to 15.0. A total of 94.8% of urate had peaks between 7.0 and 11.0. 93.8% of struvite had peaks between 11.0 and 13.0, and 90.9% of brushite had peaks between 12.0 and 14.0. Moreover, densities of urate, struvite and brushite were low density in iodine-based images and high-density in water-based images.

CONCLUSION

The in-vivo analysis of spectral CT in urinary stone revealed characteristics of different compositions, especially mixed compositions. An in-vivo predictive model may be constructed to distinguish stone compositions.

Large database study of urinary stone composition in South Korea: Korean Society of Endourology and Robotics (KSER) research series

Purpose

To evaluate the characteristics of urinary stone composition in a Korean population using a large database of stone composition.

Materials and Methods

From January 1, 2014, to June 30, 2019, a total of 33,078 urinary stone composition data were analyzed. Stone composition was classified into four main groups: calcium oxalate (CaOx), struvite, uric acid (UA), and calcium phosphate (CaP). We examined the relationship between stone composition and sex, age, geographic region, calendar month, and season.

Results

The CaOx group (46.41%) was the largest, followed by the struvite group (29.66%), UA group (19.61%), and CaP group (4.32%). The CaOx group tended to decrease with age, but the UA group increased with age. Also, the CaOx group had the highest percentage in summer and the lowest in spring (p<0.001). The struvite and CaP groups had higher percentages of females than males (struvite: 36.6% vs. 25.7%, p<0.001; CaP: 6.2% vs. 3.3%, p<0.001). Conversely, the UA stones were more common in males than in females (24.5% vs. 11.0%, p<0.001). The UA group had the lowest percentage in the capital region (p<0.001). The total male-to-female ratio decreased over time from 1.95:1 in 2014 to 1.67:1 in 2018 (p<0.001).

Conclusions

There were differences for each stone composition in the percentages according to sex, age, geographic region, month, and season. Identifying these differences based on the stone composition is vital for the treatment and prevention of urinary stones.

Determining the true burden of kidney stone disease

The incidence and prevalence of kidney stones have increased over the past four decades. However, the diagnosis of 'kidney stone' can range from an incidental asymptomatic finding of limited clinical significance to multiple painful episodes of ureteral obstruction with eventual kidney failure. Some general strategies may be useful to prevent the recurrence of kidney stones. In particular, greater attention to kidney stone classification, approaches to assessing the risk of recurrence and individualized prevention strategies may improve the clinical care of stone formers. Although there have been some advances in approaches to predicting the recurrence of kidney stones, notable challenges remain. Studies of kidney stone prevalence, incidence and recurrence have reported inconsistent findings, in part because of the lack of a standardized stone classification system. A kidney stone classification system based on practical and clinically useful measures of stone disease may help to improve both the study and clinical care of stone formers. Any future kidney stone classification system should be aimed at distinguishing asymptomatic from symptomatic stones, clinically diagnosed symptomatic stone episodes from self-reported symptomatic stone episodes, symptomatic stone episodes that are confirmed from those that are suspected, symptomatic recurrence from radiographic recurrence (that is, with radiographic evidence of a new stone, stone growth or stone disappearance from presumed passage) and determine stone composition based on mutually exclusive categories.

Upper urinary tract stone compositions: the role of age and gender

Objective:

To analyze the compositions of upper urinary tract stones and investigate their distributions in different gender and age groups.

Materials and Methods:

Patients diagnosed with upper urinary tract stone disease between December 2014 and March 2018 were retrospectively reviewed. Patient's age, gender, BMI, comorbidities, stone event characteristics, and compositions were collected, and proportions of stone components in different gender and age groups were analyzed.

Results:

A total of 1532 stone analyses were performed (992 from males and 540 from females). The mean age was younger in males (p <0.001). Males included more cases with larger BMI, hyperuricemia, and obesity, while females had more urinary tract infections. Multiple components were present in 61.8% of stones. Calcium oxalate (CaOx) (67.0%) was the most common component, followed by uric acid (UA) (11.8%), infection stone (11.4%), calcium phosphate (CaP) (8.0%), cystine (1.1%), brushite (0.4%), and 2, 8-dihydroxyadenine (0.2%). Men contributed with more CaOx stones than women at age 30-49 years (all p <0.01) and more UA stones at 30-59 years (all p <0.05). Women contributed with more infection stones than men in age groups 30-49 and 60-69 years (all p <0.05), and more CaP stones at 30-49 years. The prevalence peak was 50-59 years in men and 60-69 years in women. Both genders had the lowest prevalence in adolescence. Prevalence of UA stones increased while that of infection stones decreased with aging in both genders.

Conclusions:

Age and sex had a strong association with distribution of stone compositions in this Chinese cohort.

Overexpression of miR‑30c‑5p reduces cellular cytotoxicity and inhibits the formation of kidney stones through ATG5

MicroRNAs (miRNAs or miRs) are critical regulators in various diseases. In the current study, the role of miR-30c-5p in the formation of sodium oxalate-induced kidney stones was investigated. For this purpose, human renal tubular epithelial cells (HK-2 cells) were incubated with sodium oxalate at the concentrations of 100, 250, 500, 750 and 1,000 µM. Cell viability and the miR-30c-5p expression level were respectively measured by CCK-8 assay and RT-qPCR. After separately transfecting miR-30c-5p mimic and inhibitor into the HK-2 cells, the cell apoptotic rate, the levels of mitochondrial membrane potential (MMP) and ROS were determined by flow cytometry. The levels of oxidative stress indicators [lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT)] were determined using commercial kits. Crystal-cell adhesion assay was performed to evaluate the crystal adhesion capacity in vitro. miR-30c-5p binding at autophagy related 5 (ATG5) was predicted by TargetScan7.2 and further verified by dual-luciferase reporter assay. Rescue experiments were performed to confirm the molecular mechanisms underlying sodium oxalate-induced kidney formation in HK-2 cells. The results revealed that sodium oxalate decreased the viability of HK-2 cells in a concentration-dependent manner, and that miR-30c-5p expression was significantly downregulated by exposure to 750 µM sodium oxalate. In addition, the increase in cell apoptosis and crystal number, and the upregulated levels of LDH, MDA and ROS were reversed by the overexpression of miR-30c-5p. Moreover, the overexpression of miR-30c-5p upregulated the levels of SOD, CAT and MMP induced by sodium oxalate. ATG5 was directly regulated by miR-30c-5p, and the inhibition of cell cytotoxicity and crystal-cell adhesion induced by miR-30c-5p mimic was blocked by ATG5. These data indicated that the overexpression of miR-30c-5p alleviated cell cytotoxicity and crystal-cell adhesion induced by sodium oxalate through ATG5. Thus, the current study provides a better understanding of the role of miR-30c-5p in sodium oxalate-induced kidney stones.