Epidemiology of Kidney Stones

SMART Stone Multidisciplinary Team (MDT) and patient care: recommendations for the adult high-risk kidney stone patient pathway

PURPOSE

The SMART Stone Multidisciplinary Team (MDT) recommendations aim to provide guidance on the role of the MDT in the early identification, referral and assessment of adult high-risk recurrent kidney stone formers to advance patient care.

METHODS

Recommendations were developed by the expert Steering Committee (SC) comprising of three Urologists, one Nephrologist, and two Biochemists/Geneticists from the UK, Spain, Germany, and Italy. These recommendations were voted on by invited specialists via an online survey to determine their level of agreement, from 'strongly agree' to 'strongly disagree'. With an agreement threshold set at ≥ 70%, the SC reviewed the survey results, additional comments, and any areas of disagreement before finalizing the recommendations.

RESULTS

A total of 44 recommendations were developed by the SC designed to support the set-up of an ideal MDT. Thirteen core recommendations were chosen as being highest priority and were voted on by 29 invited specialists from 19 countries across Europe, Canada, East Asia, South/Southeast Asia, and the Middle East. All 13 core recommendations reached the ≥ 70% agreement threshold. The remaining 31 recommendations were voted on by those specialists who opted-in to partake in the extended questionnaire. Fifteen specialists provided their responses from 14 different countries. All 31 recommendations reached the ≥ 70% agreement threshold.

CONCLUSIONS

An ideal MDT process can achieve comprehensive, high-quality, and coordinated patient care, which is especially useful for patients with complex stone diseases. A high level of agreement was reached in areas relating to the implementation of an ideal MDT in identifying high-risk stone formers.

Appraisal of Spanish-language online patient education resources for kidney stones

INTRODUCTION

The internet is a primary source of health information, our study addresses the need to assess the credibility, readability, and reliability of Spanish-language medical websites concerning nephrolithiasis. With the Spanish-speaking population in the United States rapidly approaching 20% and growing, our research endeavors to fill a critical gap by evaluating the quality of online resources in Spanish for this common medical condition.

METHODS

In our study, we evaluated the quality of Spanish-language online resources on nephrolithiasis for the growing Spanish-speaking population in the United States. Using Google searches with terms like "cálculos renales" and "nefrolitiasis," we analyzed 80 unique websites using Fernandez-Huerta readability software, HON-code certification, JAMA benchmark criteria, source classification, and brief DISCERN. The evaluation was performed by an expert urologist and a medical student, with discrepancies resolved by a third experienced reviewer.

RESULTS

Interrater reliability was strong for JAMA (ICC: 0.98) and DISCERN (ICC: 0.85). Websites mainly originated from Physician/Community Hospitals (43.75%) and University/Academic institutions (23.75%). Only 32.5% had HON-code certification, and 17.5% met all JAMA criteria. Readability typically matched an 8th to 9th grade level, but 58.75% scored below the good quality threshold on DISCERN, with University/Academic sources performing significantly better than Physician/Community sources (p = 0.0078). No significant differences were noted in credibility or readability between these groups.

CONCLUSIONS

Our findings indicate that Spanish-language resources on nephrolithiasis often lack in quality, readability, and credibility, highlighting the need for enhanced online materials to support patient and provider management of kidney stones. University sources provide notably higher-quality information than other resource types.

Is silodosin better than tadalafil as a medical expulsive therapy in lower ureter stones?

OBJECTIVE

This meta-analysis aims to compare the efficacy and safety of tadalafil and silodosin as medical expulsive therapy (MET) for lower ureteric stones below 10 mm. The study also assesses the incidence of adverse effects associated with each drug.

METHODS

A comprehensive search of electronic databases was conducted up to October, 2024. The study included randomized controlled trials (RCTs) and cohort studies that compared tadalafil and silodosin in patients with lower ureteric stones (5-10 mm). The primary outcomes assessed were stone expulsion time (SET), stone expulsion rate (SER), and adverse effects. Data were analyzed using a random-effects model for heterogeneity and a fixed-effect model for non-heterogeneity.

RESULTS

Eight studies involving 797 patients were included. The pooled analysis showed no significant difference in SET between tadalafil and silodosin (MD = 0.15, 95% CI [-0.28, 0.57], p=0.50), with significant heterogeneity. Similarly, the pooled analysis showed no significant difference in SER between the two drugs (RR = 0.92, 95% CI [0.80 to 1.05], p=0.22), with heterogeneity. However, after excluding one study, silodosin was favored over tadalafil for SER (RR 0.88, 95% CI [0.79 to 0.98], p=0.02). There were no significant differences in headache, backache, or dizziness. Silodosin was associated with a higher incidence of orthostatic hypotension, but this was resolved by excluding one study. A significant difference for abnormal ejaculation favored tadalafil (RR = 0.16, 95% CI [0.09 to 0.29], p=0.01).

CONCLUSIONS

While the pooled results initially showed no significant difference in SET and SER, silodosin demonstrated a superior stone expulsion rate after adjusting for heterogeneity silodosin showed a trend towards shorter SET. However, silodosin was associated with a higher risk of orthostatic hypotension and abnormal ejaculation. Further high-quality RCTs with larger sample sizes are needed to confirm these findings.

Environmental determinants in the development of kidney stone

The increase with years of kidney stone prevalence has become a serious public health problem worldwide. The geographical distribution pattern of kidney stone (known as "stone belt") clearly indicates the critical role of environmental exposure in its formation, which has long been an underestimated risk factor in studying the development of kidney stone. Based on our previous studies and bibliometric analysis, we discerned four environmental determinants and elaborated their impacts on human internal exposure related to kidney stone formation. The importance of climatic factor lies in that the relatively high temperature and low humidity environment may contribute greater prevalence of kidney stone, since it promotes elevating the concentration of relatively insoluble stone-forming salts. Geological factors including water quality, hydrogeology, and soil environment is involved in kidney stone formation via the food chain. Additionally, air pollution and heavy metal pollutants also act as potential risk factors by directly or indirectly affecting the normal renal function and urinary metabolism. This review thus provides insights into the specific mechanisms affecting metabolic changes in the human body which result in kidney stone formation under environmental exposure, and shed light on the pathogenesis of nephrolithiasis from an interdisciplinary perspective.

Safety and efficacy of mini-percutaneous nephrolithotomy in management of renal stones in pediatric age group

BACKGROUND

Currently, kidney stones are frequently observed in children and teens.

OBJECTIVES

To evaluate the safety and efficacy of mini-percutaneous nephrolithotomy (MPCNL) in managing renal stones in pediatric patients.

PATIENTS AND METHODS

This retrospective case series study included 115 consecutive patients aged < 11 years old who underwent MPCNL at Sulaimani Teaching Hospital and Mercy Medical City, Sulaimaniyah, Iraq, from January 2016 to March 2021. MPCNL was done on all patients through 16-20 Fr tracts. The stone-free rate, perioperative complications, tract number, operative time, postoperative hemoglobin change, and hospitalization time were assessed.

RESULTS

The mean patients' age was 6.53 ± 1.3 years, and the mean stone burden was 2.073 ± 1.03 cm2. After a single session of MPCNL, 93.25% of patients attained a complete stone clearance through a single tract in 109 patients (94%) and two tracts in 6 patients (5.2%). Hospitalization time, operative time, postoperative hemoglobin drop, and perioperative complications were 2.23 ± 0.93 days, 39.26 ± 8.22 min, 0.51 ± 0.34 g/dL, and 25.21%, respectively. No major complications (Clavien grade III and IV) were found. Most complications were minor, including Clavien grade I (n = 18, 15.6%) and II (n = 11, 9.56%), which were managed conservatively.

CONCLUSIONS

MPCNL is an effective and potentially safe procedure for treating complex renal stones in pediatric patients aged < 11 years, yielding an excellent stone-free rate and acceptable complications.

Changing trends in clinical presentation of primary hyperparathyroidism across countries over time

Primary hyperparathyroidism (PHPT), the third most common endocrine disorder, was so eloquently described first by Fuller Albright as a polymorphic condition in his classic paper and monograph as early as 1934. Over the decades, the clinical presentation of PHPT in developed countries has shifted significantly from a disease primarily affecting the bones and kidneys to an asymptomatic condition often discovered incidentally. In developing countries, the high prevalence of vitamin D deficiency is one of the main factors influencing the clinical presentation of PHPT. In Europe and North America, PHPT is predominantly asymptomatic. In South America, China, and Eastern parts of Europe, such as Turkey, Bulgaria, and Russia, there is an ongoing transition from symptomatic to asymptomatic cases. Asia shows variability: symptomatic cases dominate in the Indian subcontinent, Middle East, and Southeast Asia, while transitional patterns with predominant asymptomatic cases have now been reported in China, and Japan reports mostly asymptomatic cases. Factors influencing these changes include advancements in diagnostic technologies, detection of incidental parathyroid adenomas during thyroid ultrasonography, regional differences in vitamin D deficiency, dietary habits, and genetic polymorphisms in vitamin D and calcium-sensing receptors. A higher prevalence of nephrolithiasis in certain climates contributes to regional variations. This review examines the dynamic nature of PHPT's clinical presentation, shaped by geographic, genetic, and environmental influences. Also, this review highlights the importance of addressing global disparities in an attempt to optimize patient outcomes.

A case report of minimally invasive management of congenital retrocaval ureter

Retrocaval ureter (RU) is a rare congenital malformation where the ureteric pathway is altered, passing posteriorly around the inferior vena cava (IVC). Occasionally, this leads to the IVC compressing the ureter, resulting in obstruction. In this report, we discuss a male who presented with severe right-sided flank pain and was otherwise well with no significant medical, urological, or birth history. Initial imaging revealed severe right-sided hydroureter with distinct obstruction point, and likely RU. Anecdotal and small centre cases of acute management and laparoscopic RU repair were reviewed. Initial management focused on pain control requiring a nephrostomy with subsequent transperitoneal laparoscopic dissection and repair. Operative time was 138 min with 50 mL blood loss. Post-operatively the patient recovered well and was symptom free at 6 month follow up ultrasound. Similarly, most reviewed cases chose a trans-peritoneal laparoscopic approach with good outcomes.

Disrupting Biofilms on Human Kidney Stones-A Path Toward Reducing Infectious Complications During Stone Surgery

Kidney stones are a common disorder associated with significant morbidity and often requires surgical intervention. Pathogenic bacteria are found in almost 40% of stones, where they form biofilms that are protected from systemic antibiotic treatments. Stone surgeries disperse biofilms resulting in up to 30% of patients developing postoperative urinary tract infections and 15% developing sepsis. This work is based on the hypothesis that chitosan, an antimicrobial polymer, can eradicate bacterial biofilms present in the stone and potentially serve as an adjunct to irrigation during stone surgery. First, fresh patient-derived kidney stone fragments (n = 56) are collected from stone surgeries. A total of 32% of stones are colonized, predominantly with Enterococcus faecalis, Escherichia coli, and Proteus mirabilis. A short, clinically relevant, chitosan treatment reduces the bacterial burden on colonized stones by over 90% in all specimens tested, regardless of stone composition and bacterial strain. To assess this approach toxicity, ex vivo human ureters and in vivo porcine bladders are exposed to topical chitosan irrigation. No toxic or pathological abnormalities other than urothelial exfoliation are noted. In conclusion, chitosan effectively disrupts kidney stone-associated bacterial biofilms with minimal urothelial toxicity and may provide an effective and safe approach to reducing postoperative complications.

Low Serum and Urine Fetuin-A Levels and High Composite Dietary Antioxidant Index as Risk Factors for Kidney Stone Formation

Background: Fetuin-A prevents the precipitation of hydroxyapatite in supersaturated solutions of calcium and phosphate; however, its relationship with nephrolithiasis has yet to be clarified. The aim of this study was to investigate the protective and predictive roles of serum and urine fetuin-A levels in nephrolithiasis and their relationships with the composite dietary antioxidant index (CDAI). Methods: This study involved 75 adult patients with kidney stone disease and 71 healthy adults without kidney stone disease in the control group. Participants had specific anthropometric measurements taken, and three-day food records were kept. The CDAI was calculated by summing six standard antioxidants, including vitamins A, C, and E, manganese, selenium, and zinc, representing participants' antioxidant profile. In addition to some analyzed serum and urine parameters of the participants, fetuin-A levels were measured using the enzyme-linked immunosorbent assay (ELISA) method. Results: In patients with kidney stones, both serum and urine fetuin-A levels (676.3 ± 160.14 ng/mL; 166.6 ± 128.13 ng/mL, respectively) were lower than in the control group (1455.6 ± 420.52 ng/mL; 2267.5 ± 1536.78 ng/mL, respectively) (p < 0.00001). In contrast, the CDAI was higher in patients with kidney stones compared to those without kidney stones (p < 0.001). Besides, several dietary parameters had significant positive correlations with serum and/or urinary fetuin-A. Conclusions: The present study suggests that serum and urinary fetuin-A levels may serve as protective factors against kidney stones and could potentially be used as predictive markers for the development of nephrolithiasis. Furthermore, our results suggest that the CDAI above a certain level may increase the risk of stone formation and that some dietary parameters may affect the levels of this biomarker in serum and urine.

Inverse association between prognostic nutritional index and kidney stone prevalence: A population-based study

BACKGROUND

Kidney stones frequently occur due to metabolic disorders, dietary habits, and lifestyle influences. The Prognostic Nutritional Index, which reflects an individual's nutritional condition, might be associated with kidney stone prevalence. This study examines the association between PNI and kidney stone prevalence in US adults.

METHODS

The study used data from the National Health and Nutrition Examination Survey database from 2009-2018 and excluded pregnant women, and individuals who lacked data on kidney stones, or had incomplete Prognostic Nutritional Index data. Independent associations between Prognostic Nutritional Index and kidney stones were investigated by multivariate logistic regression and subgroup analyses, in addition to exploring nonlinear associations using smoothed curves and threshold effects.

RESULTS

A total of 13,835 participants aged ≥ 20 years were included, with a kidney stone prevalence of 8.48%. An inverse association was observed between the Prognostic Nutritional Index and kidney stone prevalence (OR =  0.97, 95% CI =  0.96-0.98, P <  0.001). This relationship was not significantly modified by race, education, marital status, or comorbidities such as hypertension, diabetes, and hyperlipidemia. However, sex and total cholesterol levels influenced the association. Stratified analysis showed a significant negative association in men (OR =  0.98, 95% CI =  0.96-0.99, P =  0.031), but not in women. A nonlinear relationship was identified in individuals with total cholesterol ≥  5.2 mmol/L, with a significant negative association below the inflection point of 57 (OR =  0.96, P =  0.012) and a positive association above it (OR =  1.11, P =  0.03). These findings suggest that the Prognostic Nutritional Index is inversely associated with kidney stones, particularly in men and those with high cholesterol levels.

CONCLUSION

The Prognostic Nutritional Index was negatively associated with the risk of kidney stones, particularly in men and individuals with high cholesterol levels below the identified inflection point, suggesting that tailored nutritional management may be crucial for these subgroups.

Dual graph-embedded fusion network for predicting potential microbe-disease associations with sequence learning

Recent studies indicate that microorganisms are crucial for maintaining human health. Dysbiosis, or an imbalance in these microbial communities, is strongly linked to a variety of human diseases. Therefore, understanding the impact of microbes on disease is essential. The DuGEL model leverages the strengths of graph convolutional neural network (GCN) and graph attention network (GAT), ensuring that both local and global relationships within the microbe-disease association network are captured. The integration of the Long Short-Term Memory Network (LSTM) further enhances the model's ability to understand sequential dependencies in the feature representations. This comprehensive approach allows DuGEL to achieve a high level of accuracy in predicting potential microbe-disease associations, making it a valuable tool for biomedical research and the discovery of new therapeutic targets. By combining advanced graph-based and sequence-based learning techniques, DuGEL addresses the limitations of existing methods and provides a robust framework for the prediction of microbe-disease associations. To evaluate the performance of DuGEL, we conducted comprehensive comparative experiments and case studies based on two databases, HMDAD, and Disbiome to demonstrate that DuGEL can effectively predict potential microbe-disease associations.

Ethnic diversity and urolithiasis: a single-center experience

Despite the diversity in the prevalence and risk factors of urolithiasis across different geographic regions, limited information exists among various ethnic groups of the same population. This study investigates the prevalence of kidney stones (KSs) among different ethnicities in a single center in Qatar and the risk factors associated with KS formation. This retrospective cross-sectional study was on Qatari residents who visited Al-Khor Hospital between January 1, 2014 and December 31, 2019. All adult permanent residents who presented with KSs or visited the hospital for general check-ups and for whom the required data were available were included. There was a highly significant difference in KS prevalence among ethnicities (p-value < 0.001). The Egyptians had the highest prevalence of KSs (78.5%), followed by Qataris (65.0%), Palestinians (63.5%), Bangladeshis (59.4%), Syrians (55.9%), Jordanians (53.8%), and Yemenis (53.5%). However, no significant difference was found when comparing the different races regarding urolithiasis (p-value = 0.19). Individuals with hypertension and diabetes mellitus had a significantly higher prevalence of KSs (p-value = 0.001). Among patients with prior renal surgery and positive family history, 59.9% and 70.5% had KSs, compared to 49.1% and 48.3% without previous surgery and negative family history (p-values = 0.002 and < 0.001, respectively). Smoking, poor dietary intake, alcohol consumption, and severe exposure to sunlight were significantly associated with KSs (p-value < 0.001). Urolithiasis among the Qatari population is multifactorial and shows variation based on ethnicity, with natives being the second most frequently affected group.

Advancements in Nanomedicine for the Diagnosis and Treatment of Kidney Stones

Kidney stones constitute a common condition impacting the urinary system. In clinical diagnosis and management, traditional surgical interventions and pharmacological treatments are primarily utilized; however, these methods possess inherent limitations. Presently, the field of nanomedicine is undergoing significant advancements. The application of nanomaterials in biosensors enables the accurate assessment of urinary ion composition. Furthermore, contrast agents developed from these materials can improve the signal-to-noise ratio and enhance image clarity. By mitigating oxidative stress-induced cellular damage, nanomaterials can inhibit the formation of kidney stones and enhance the efficacy of drug delivery as effective carriers. Additionally, by modifying the physical and chemical properties of bacteria, nanomaterials can effectively eliminate bacterial presence, thereby preventing severe complications. This review explores the advancements in nanomaterials technology related to the early detection of risk factors, clinical diagnosis, and treatment of kidney stones and their associated complications.

Unveiling the antiurolithiatic potentiality of two benzene sulfonamide derivatives against ethylene glycol-induced renal calculi

OBJECTIVE

Oxidative stress and inflammation play crucial roles in the onset of kidney injury and crystal formation caused by hyperoxaluria. Indapamide is a potent medication for treating renal calculi, but it has severe side effects such as hypokalemia, hypercalcemia, and hyperuricemia. Therefore, it is advisable to explore alternative treatments that do not have these side effects. The study aimed to reveal the antiurolithiatic potential of two benzene sulfonamide derivatives (SBCl and SBF; A and B, respectively) against ethylene glycol-induced kidney stones.

METHODS

The rats were divided into two main groups: the first group consisted of 20 rats with induced kidney stones, and the second group included 15 control rats. This division enabled a comparative analysis between rats with kidney stones and those without, offering insights into the effects of kidney stone induction on various physiological parameters and biochemical markers. The effectiveness of benzene sulfonamide derivatives (compounds A and B) was assessed in rats with induced kidney stones. The treatment was given orally by gavage for 21 days, administered every 48h after inducing kidney stones with 0.12ml of 5% ethylene glycol (EG).

RESULTS

The influence of compounds A and B on electrolytes, biochemical, antioxidant, and inflammatory reactions in induced kidneys underscores their potential therapeutic advantages in alleviating the advancement of kidney stone disease and related complications.

CONCLUSION

Both compounds were found to possess equal effectiveness in inhibiting the complications of stone formation. However, SBCl-EG showed superior antioxidant and inflammatory parameters effects compared to SBF-EG. Our study's findings underscore the potential benefits of derivatives in treating nephrolithiasis and related oxidative disorders, highlighting their superior effects on antioxidant and inflammatory responses compared to standard treatments.

Imaging in Urolithiasis

Urolithiasis has high incidence in industrialized countries (0.5% in Europe and North America). Its high incidence along with the severity of clinical symptoms makes nephrolithiasis an important consideration in patients with acute abdominal pain. Imaging has a pivotal role and non-contrast computed tomography scan is the gold standard examination in both the diagnosis and follow-up of patients with urolithiasis. Ultrasound and kidneys, ureters, and bladder radiography are also essential tools in the follow-up of this pathology given its high recurrence rates while MRI can be used in special patient populations such as pregnant women.

Does type of anesthesia during procedural management of suspected renal colic during pregnancy have an impact on preterm birth?

INTRODUCTION

Anesthesia choice during the procedural management of suspected renal colic during pregnancy may vary based on available resources and patient or provider preferences, as there are no specific recommendations. Our objective was to evaluate whether preterm birth (<37 weeks) was associated with anesthesia type, anesthesia timing by trimester, or procedure type.

METHODS

We retrospectively identified pregnant patients who required procedural management with ureteral stent, percutaneous nephrostomy (PCN), or ureteroscopy (URS) for suspected renal colic based on laboratory and imaging findings from 2009-2021 at our center. Analyzed data included anesthesia type (local analgesia only, monitored anesthesia care [MAC], spinal anesthesia, or general anesthesia), trimester of procedure, procedure type, and obstetric outcomes, including preterm birth.

RESULTS

The study cohort included 96 patients who underwent 231 total procedures, including primary URS, PCN, and stent, as well as PCN and stent change. The median gestational age was 38.7 weeks (37.1-39.5), and preterm birth rate was 15.8%. The most common anesthetic used across all procedures and trimesters was MAC. PCN was associated with the use of less invasive analgesia or anesthesia, whereas endoscopic procedures were more commonly performed with spinal or general anesthesia. Using multivariable logistic regression, procedure type was associated with preterm birth, but not anesthesia type or timing by trimester.

CONCLUSIONS

Anesthesia type and timing were not associated with preterm birth, and selection may be influenced by resources, clinical scenario, or patient and provider preferences.

Potassium Sodium Hydrogen Citrate in Managing Surgical Candidates With Urinary Stones: A Case Series

Kidney stone disease is highly prevalent in Saudi Arabia, where conventional treatments often involve invasive procedures that carry significant risks. This case series examines the efficacy of potassium sodium hydrogen citrate as a non-invasive alternative for managing kidney stones. Five patients with complex medical histories, large stone sizes, and diverse stone compositions were treated with this therapy, resulting in complete stone dissolution without the need for surgical intervention. The findings highlight the potential of this approach to effectively dissolve stones and prevent recurrence, particularly for patients deemed unsuitable for surgery. Despite its proven efficacy, the adoption of chemical management remains underutilized in Saudi Arabia. Incorporating potassium sodium hydrogen citrate into the standard treatment protocols could reduce dependence on invasive procedures, improve patient outcomes, and alleviate the burden on healthcare resources.

Time-sensitive elements in elective treatment of urinary lithiasis: a narrative review

Background and Objective

Managing surgical queues for urinary lithiasis is a persistent challenge in healthcare systems. Despite substantial research in this area, clear criteria for prioritizing patients and determining those who can safely wait longer without complications remain elusive. This review aims to develop a rational framework for optimizing surgical queue management in urinary stone treatment by analyzing primary literature.

Methods

We conducted a review of relevant guidelines, held departmental discussions to identify additional factors, and performed an extensive PubMed search using key terms related to queue management and expectant care in lithiasis.

Key Contents and Findings

Significant factors identified include stone volume and location, presence of hydronephrosis, patient frailty and comorbidities, recurrent urinary infections, nephrostomy or double-J stent, urinary diversion, high occupational risk, limited healthcare access, and refractory pain impacting quality of life. A detailed analysis of these factors is presented in the article.

Conclusions

Effective management of surgical waitlists for urinary lithiasis requires a comprehensive assessment of factors such as stone characteristics, hydronephrosis, patient frailty, comorbidities, infections, drainage devices, accessibility, and quality of life, as prioritization based solely on waiting time is insufficient and potentially harmful.

Increased efficacy in lower pole stone management with a novel flexible and navigable suction ureteral access sheath with flexible ureteroscopic lithotripsy: a case series

Background

The flexible and navigable suction ureteral access sheath (FANS-UAS) is regarded as a complement to flexible ureteroscopy in retrograde intrarenal surgery. Management of lower pole stones (LPS) is challenging due to the difficulty of anatomical access to the inferior renal calyx.

Case Description

The novel FANS-UAS (11/13.5 Fr; 40/50 cm length; 7 cm navigable tip length; 180° angulation) from Well Lead Medical (Guangzhou, China) has been commercially-available in July 2024 and first-used in The University of Hong Kong-Shenzhen Hospital. This case series included five candidates (three males; mean age 37.8±15.1 years) with LPS (max. diameter 7-10.5 mm) undergoing FANS-UAS with flexible ureteroscopic lithotripsy. Success rate of FANS-UAS catheterization was 80% as a male patient displayed poor ureter elasticity intraoperatively and the operation had to be completed with a 10/12 Fr tip-flexible UAS and stone basket. LPS, including those with an infundibulopelvic angle <30°, could be easily navigated and removed with insignificant to no residual stones remaining. No stone basket was used. Grade I and II ureteric injuries occurred in two separate patients that were resolved upon four weeks of ureteral stenting. No significant intra- and post-operative complication was observed. The mean total operative duration was 66.5±22.6 minutes. Computed tomography scans were conducted at day one post-operation. Among the cases with successful FANS-UAS insertion, the absolute and relative stone free rate, defined as complete absence and absence of residual fragments <2 mm, was 75% and 100%, respectively. All patients remained stone-free at one-month follow-up with no adverse events.

Conclusions

Early outcomes of the novel 11/13.5 Fr FANS-UAS applied successfully on four patients demonstrate its feasibility, safety, and efficiency in removing LPS. However, improvements in design may be necessitated in the future. For the meantime, prolonged follow-up and larger patient samples are necessitated to further elucidate its outcomes and prognosis.

Lifestyle Factors and the Microbiome in Urolithiasis: A Narrative Review

Urolithiasis represents one of the most common urologic diseases, and its incidence demonstrates, globally, an increasing trend. The application of preventive measures is an established strategy to reduce urolithiasis-related morbidity, and it is based mostly on the adaptation of lifestyle factors and pharmacotherapy. Furthermore, other research areas demonstrate promising results, such as the research on the microbiome. In the current review, we searched for the latest data on lifestyle-based prevention and microbiome alterations in urolithiasis patients. The majority of the proposed lifestyle measures are already included in the urological guidelines, while additional factors, such as vitamin D supplementation, seem to have a putative positive effect. From the microbiome studies, several microbial composition patterns and metabolic pathways demonstrated an inhibiting or promoting role in lithogenesis. Up to the present, stone prevention has not shown satisfying results, which suggests that lifestyle measures are not adequate. Moreover, microbiome studies are prone to bias, since microbes are strongly affected by numerous clinical factors, while the analysis procedures are not standardized yet. Analysis standardization and data pooling from extensive registration of clinical and microbiome data are essential steps in order to improve the existing prevention strategy with targeted microbiome manipulations.

Exploring susceptibility and therapeutic targets for kidney stones through proteome-wide Mendelian randomization

Given the high recurrence rate of kidney stones, surgical lithotripsy and stone removal are not the ultimate treatments for kidney stones. There's an urgent need to explore the genetic mechanisms behind the susceptibility to kidney stones and to identify potential targets for prevention, to reduce the renal damage caused by recurrent stone formation. In this study, we screened 4548 circulating proteins using proteome-wide Mendelian Randomization (MR) to find proteins with a causal relationship to kidney stone risk. Additionally, proteome-wide association study (PWAS) and colocalization analysis were used to validate and prioritize candidate proteins. Moreover, downstream analyses including single-cell analysis, enrichment analysis, protein-protein interaction (PPI), and druggability analysis were conducted on the proteins causally related to kidney stones, to further explore the genetic mechanisms of susceptibility and the potential of proteins as drug targets. Ultimately, 22 target proteins associated with the risk of kidney stones were identified. Six plasma proteins (COLGALT1, CLMP, LECT1, ITIH1, CDHR3, CPLX2) were negatively correlated with kidney stone risk, while the genetic overexpression of 16 target proteins (GJA1, STOM, IRF9, F9, TMPRSS11D, ADH1B, SPINK13, CRYBB2, TNS2, DOCK9, OXSM, MST1, IL2, LMAN2, ITIH3, KLRF1) increased the risk of kidney stones. Based on the PWAS and colocalization analysis results, the 22 target proteins were classified into 3 tiers: IL2, CPLX2, and LMAN2 as tier 1 proteins with the most compelling evidence, MST1, ITIH1, and ITIH3 as tier 2 proteins, and the rest as tier 3 proteins. Enrichment analysis and PPI showed that target proteins mainly affect the occurrence of kidney stones through leukocyte activation and cell junction assembly. Druggability analysis suggested that IL2, MST1, and ITIH1 have potential as drug targets, and potential drugs were evaluated through molecular docking. In summary, this study employed multiple analytical methods to screen plasma proteins related to susceptibility to kidney stones, providing new insights into the genetic mechanisms of kidney stones and potential targets for treatment and prevention.

Current Status of Gout Arthritis: Current Approaches to Gout Arthritis Treatment: Nanoparticles Delivery Systems Approach

The deposition of monosodium urate (MSU) crystals within joint spaces produces a painful inflammatory condition known as gout, a specific form of arthritis. The condition calls for a combined curative and preventive management model. A new development in the approach to gout is that of NLRP3-targeted biologic agents, such as monoclonal therapies, to provide more accurate treatment by blocking specific pro-inflammatory cytokines. Nanoparticle drug delivery enhances biological availability and delivery to targets, which may increase therapeutic efficacy and decrease general toxicity. The preventive approach again cannot be ignored, mainly keeping up certain modifications in diet and weight, along with pharmacological therapies to reduce uric acid (UA) levels and to decrease the frequency of acute attacks. The advancement of genetic profiling of patients and biomarker discoveries drives the trend towards building individualized medicine and care, quickly gaining ground as the most effective method of delivering treatments to individual patients, moving away from one-size-fits-all treatments. The following paper aims to provide an updated account of the management of gout with a focus on recent developments, in order to enhance these approaches, the quality of life for patients with gout, and the standard of gout treatment.

Label-free detection of kidney stones urine combined with SERS and multivariate statistical algorithm

Kidney stones are a common urological disease with an increasing incidence worldwide. Traditional diagnostic methods for kidney stones are relatively complex and time-consuming, thus necessitating the development of a quicker and simpler diagnostic approach. This study investigates the clinical screening of kidney stones using Surface-Enhanced Raman Scattering (SERS) technology combined with multivariate statistical algorithms, comparing the classification performance of three algorithms (PCA-LDA, PCA-LR, PCA-SVM). Urine samples from 32 kidney stone patients, 30 patients with other urinary stones, and 36 healthy individuals were analyzed. SERS spectra data were collected in the range of 450-1800 cm-1 and analyzed. The results showed that the PCA-SVM algorithm had the highest classification accuracy, with 92.9 % for distinguishing kidney stone patients from healthy individuals and 92 % for distinguishing kidney stone patients from those with other urinary stones. In comparison, the classification accuracy of PCA-LR and PCA-LDA was slightly lower. The findings indicate that SERS combined with PCA-SVM demonstrates excellent performance in the clinical screening of kidney stones and has potential for practical clinical application. Future research can further optimize SERS technology and algorithms to enhance their stability and accuracy, and expand the sample size to verify their applicability across different populations. Overall, this study provides a new method for the rapid diagnosis of kidney stones, which is expected to play an important role in clinical diagnostics.

Clinical efficacy of flexible ureteroscopy with holmium laser lithotripsy for geriatric patients with complex upper urinary tract calculi

The study aims to compare the efficacy of flexible ureteroscopy (FURS) with holmium laser lithotripsy (HLL, herein collectively referred to as FURS-HLL) and percutaneous nephrolithotomy (PCNL) in the treatment of complex upper urinary tract calculi in elderly patients, highlighting the advantages of FURS-HLL. A total of 40 elderly patients (aged ≥ 60) with complex upper urinary tract calculi admitted to the Department of Urology, Fuyong People's Hospital from October 2020 to October 2023 were randomly divided into 2 groups on the basis of the treatment they received: the FURS-HLL group (preset ureteral stent) and the PCNL group. The operation time, intraoperative blood loss, hospital stay, stone-free rate, and postoperative complications (fever, hematuria, infection, and severe urinary tract injury) were compared and analyzed between the 2 groups. There were no statistically significant differences in the average age, sex, stone diameter, stone type, and underlying diseases between the 2 groups (P > .05). The FURS-HLL group had significantly less intraoperative blood loss, shorter hospital stays, and longer operation time than the PCNL group (P < .05). The postoperative infection rate and the 1-week stone-free rate were lower in the FURS-HLL group than in the PCNL group (P < .05). However, there were no statistically significant between-group differences in postoperative fever, hematuria, urinary tract injury, 1-month stone-free rate, and the rate of secondary surgery (P > .05). FURS-HLL can significantly improve the stone-free rate and reduce postoperative complications, making it an ideal surgical approach for elderly patients with complex upper urinary tract calculi.

Intelligent Ureteral Stent Placeable via Standard Procedure for Kidney Pressure Telemetry: An Ex-Vivo Study

This paper reports the first telemetric ureteral stent compatible with common placement procedure, enabling wireless sensing and detection of ureteral obstruction and resultant kidney swelling known as hydronephrosis at an early stage. This sensor-integrated "intelligent" ureteral stent is prototyped via the design and fabrication approaches that raise the practicality of the device and tested in a harvested swine kidney-ureter model ex vivo. Leveraging a polymeric double-J stent and micro-electro-mechanical systems technology, the intelligent stent is built by embedding micro pressure sensors and a radiofrequency antenna, forming a resonant circuit that enables wireless kidney pressure monitoring in an operating frequency of 40-50 MHz. The stent device is entirely packaged with Parylene-C for both biocompatibility and electrical insulation of the device in order to function in the real environment including urine, an electrically conductive liquid. A comparison between the results measured in in-vitro and ex-vivo settings show a good match in the sensitivity to applied pressure. In particular, the ex-vivo test in the kidney-ureter model pressurized with artificial urine in a cycled manner demonstrates wireless pressure tracking with a response of 1.3 kHz/mmHg, over pressures up to 37 mmHg that well covers a range of pressure increase known for chronic obstruction. This testing is enabled by the prototype placement into the ex-vivo model using the standard stenting technique and tools without noticeable functional degradation or failures, showing potential compatibility of the device with today's clinical need as a ureteral stent.

Fat Distribution and Urolithiasis Risk Parameters in Uric Acid Stone Formers and Patients with Type 2 Diabetes Mellitus

Key Points

Under a controlled diet, uric acid stone formers (UASFs) and diabetic patients have higher endogenous net acid production. Under a controlled diet, UASFs have lower ammonium-to-net acid excretion ratio. Body fat inversely correlates with urine buffer capacity in normal individuals, but this relationship is lost in diabetic patients and UASFs.

Background

Uric acid (UA) nephrolithiasis affects approximately 10% of kidney stones, with a greater preponderance among patients with obesity and diabetes mellitus (DM). UA lithogenicity is driven by abnormally acidic urine pH. Distinguishing the contribution of intrinsic (e.g ., body adiposity) versus external (e.g ., dietary) factors to UA stone propensity is challenging because of uncontrolled diets in outpatients in previously published studies.

Methods

This compilation of metabolic studies with body composition examined by dual-energy x-ray absorptiometry scan and blood and urine biochemistry collected under a controlled metabolic diet was conducted across three distinct populations: 74 UA stone formers (UASF group), 13 patients with type 2 DM without kidney stones (DM group), and 51 healthy volunteers (HV group).

Results

Compared with HVs, both UASFs and patients with DM exhibited higher levels of net acid excretion (NAE) and significantly lower urine pH and lower proportion of NAE excreted as ammonium (NH4+/NAE), all under controlled diets. UASFs exhibited significantly lower NH4+/NAE compared with patients with DM. UASFs also showed higher total body and truncal fat compared with HVs. Among the HVs, lower NH4+/NAE ratio correlated with higher truncal and total fat. However, this association was abolished in the UASF and DM groups who exhibit a fixed low NH4+/NAE ratio across a range of body and truncal fat.

Conclusions

The findings suggest a dual defect of diet-independent increase in acid production and impaired kidney NH4+ excretion as major contributors to the risk of UA stone formation. There is an inverse physiologic association between body fat content and NH4+/NAE in HVs, whereas NH4+/NAE is persistently low in UASFs and patients with DM, regardless of body fat, representing pathophysiology.

Association between atherosclerosis and the development of multi-organ pathologies

Atherosclerosis is a chronic inflammatory disease affecting the vascular system, characterised by the accumulation of modified lipoproteins, immune cell aggregation and the development of fibrous tissue within blood vessel walls. As atherosclerosis impacts blood vessels, its adverse effects may manifest across various tissues and organs. In this review, we examine the association of atherosclerosis with Alzheimer's disease, stroke, pancreatic and thyroid dysfunction, kidney stones and chronic kidney diseases. In several cases, the reciprocal causative effect of these diseases on the progression of atherosclerosis is also discussed. Particular attention is given to common risk factors, biomarkers and identified molecular mechanisms linking the pathophysiology of atherosclerosis to the dysfunction of multiple tissues and organs. Understanding the role of atherosclerosis and its associated microenvironmental conditions in the pathology of multi-organ disorders may unveil novel therapeutic avenues for the prevention and treatment of cardiovascular and associated diseases.

N-acetyltransferase 10 regulates UNC-51-like kinase 1 to reduce tubular cell injury and kidney stone formation

Objective

Among the most common chronic kidney diseases, kidney stones are second only to hypertension. Kidney stones pose a public health threat due to their increased incidence, high recurrence rate, and heavy economic burden. In this work, we investigated the potential mechanism of N-acetyltransferase 10 (NAT10) in oxidative stress and pyroptosis of renal tubular epithelial cells (RTECs).

Material and Methods

A kidney-stone cell model was simulated using calcium oxalate monohydrate (COM) in vitro. Western blot analysis of NAT10 expression and N4-acetylcytidine RNA immunoprecipitation verified the regulatory efficacy of NAT10 in Unc-51 like autophagy activating kinase 1 (ULK1) ac4C modification. The luciferase reporter gene assay further verified the interaction between NAT10 and ULK1. A kidney stone model was established using BALB/c mice injected with glyoxylic acid.

Results

COM can dose-dependently suppressed the cell viability and superoxide dismutase activity of HK-2 cells and promoted the release of lactate dehydrogenase and malondialdehyde levels (P < 0.05). COM also promoted apoptosis in HK-2 cells, upregulated the protein levels of caspase-1 and gasdermin D-N, and simultaneously enhanced the HK-2 cell secretion of interleukin-1b (IL-1b) and IL-18 (P < 0.05). The overexpression of NAT10 in HK-2 cells reversed the aforementioned effects, and that of NAT10 upregulated the messenger RNA (mRNA) levels of ULK1 and increased ac4C modification (P < 0.01). Furthermore, only the luciferase activity of the wild-type ULK1 containing NAT10 binding sites was enhanced with the upregulation of NAT10 (P < 0.001). Actinomycin D treatment showed that NAT10 overexpression extended the half-life of ULK1 mRNA (P < 0.01). Silencing of ULK1 neutralized the effects of NAT10 overexpression on COM-induced cell injury (P < 0.05). In addition, the increased expression of NAT10 inhibited crystal deposition, oxidative stress, and apoptosis in vivo (P < 0.05).

Conclusion

This study confirmed that NAT10 inhibits RTECs oxidative stress and cell pyrodeath through the enhanced ac4C modification of ULK1 and impedes kidney stone progression.

[Association between the triglyceride-glucose index and the incidence of nephrolithiasis in male individuals]

OBJECTIVE

To analyze the association between the triglyceride-glucose (TyG) index and the risk of nephrolithiasis across various demographic and clinical subgroups, aiming to enhance early diagnosis and treatment of nephrolithiasis and promote personalized care in diverse populations.

METHODS

This cross-sectional study analyzed the medical records of 84 968 adults, stratified into three categories (low, middle, high) according to their TyG index scores. To evaluate the association between the TyG index and nephrolithiasis risk, multivariable Logistic regression models were employed, adjusting for potential confounders. Additionally, piecewise linear regression models were used to investigate the non-linear dynamics of the TyG index's relationship with nephrolithiasis risk. Subgroup analyses were performed to explore variations in the effects of the TyG index across different demographic and clinical populations.

RESULTS

Increasing TyG index was associated with a higher risk of nephrolithiasis, rising from 4.36% in the low group to 8.96% in the high group (P < 0.001). In adjusted models, males in the middle and high TyG index categories demonstrated significantly elevated risks of nephrolithiasis, with odds ratios of 1.18 (95%CI: 1.07-1.31, P=0.002) and 1.29 (95%CI: 1.15-1.45, P < 0.001), respectively. Conversely, in females, the association was not statistically significant post-adjustment (OR=0.98, 95%CI: 0.82-1.16, P=0.778). Among males, for each unit increment in the TyG index below the critical threshold of 8.98, there was a notable 40% escalation in the risk of developing nephrolithiasis (OR=1.40, 95%CI: 1.24-1.58, P < 0.001). Surpassing this threshold, the TyG index no longer conferred a significant increase in risk (OR=0.91, 95%CI: 0.78-1.06, P=0.24). Subgroup analyses indicated that this association remained stable regardless of age, BMI, or hypertension status.

CONCLUSION

The TyG index is positively associated with the risk of nephrolithiasis in males, demonstrating a nonlinear dose-response relationship that becomes especially pronounced at certain index levels. This biomarker could potentially serve as a valuable clinical tool for identifying males who are at a high risk of developing nephrolithiasis, thereby enabling targeted preventive strategies. Further research is urgently needed to explore the underlying mechanisms and to verify the applicability of these results across different populations.

Between a Rock and a Short Place-The Impact of Nephrolithiasis on Skeletal Growth and Development Across the Lifespan

PURPOSE OF REVIEW

The impact of nephrolithiasis on skeletal growth and bone health across the life span of kidney stone formers is reviewed.

MAIN FINDINGS

Bone disease is an early event among kidney stone formers (SF), with distinct phenotypes according to each age, sex, menopausal status, dietary, hormonal and genetic factors. Nephrolithiasis-associated bone disorder is characterized by reduced bone mineral density (BMD) and histologically discloses low bone formation, high bone resorption and abnormal mineralization. Although hypercalciuria has been presumed to be pathogenic for bone loss in SF, the association of BMD with urinary calcium is not uniform in all studies. Hypocitraturia, metabolic disturbances, cytokines and receptors, growth factors and acid-base status may all influence skeletal outcomes. The potential link of bone disease with vascular calcification and cardiovascular disease among SF is discussed. The unique vulnerability of the younger skeleton to the effects of nephrolithiasis on attainment of peak bone mass and strength is highlighted and the association of bone loss with kidney stone formation early in life indicate the opportunity for intervention to reduce the risk of future bone fractures.

Small Diameter (7.5 Fr) Single-Use Flexible Ureteroscopy with Direct In-Scope Suction (DISSTM) in Conjunction with Aspiration-Assisted Flexible Access Sheath: A New Hype for Real Stone-Free?

Background: Renal lithiasis continues to represent a great challenge for modern urology in terms of minimally invasive management of lithotripsy procedures. The recent revolution of endoscopes with the miniaturization of instruments and the development of improved disposable ureteroscopes combined with recent suction methods such as suction access sheaths or direct in-scope suction (DISSTM) systems promise to further improve the outcome of renal stone treatment. Methods: Considering this technological advance, this study aims to evaluate the results obtained by combining these methods in three groups: Group 1-Single-use 7.5 Fr flexible ureteroscope with standard access sheath, Group 2-Single-use 7.5 Fr flexible ureteroscope with direct in-scope suction (DISSTM) with standard access sheath, Group 3-Single-use 7.5 Fr flexible ureteroscope with DISSTM with suction access sheath. A total number of 105 consecutive patients were enrolled in the study, divided equally in each group. Several parameters were followed, such as size and location of the stones, operative time, duration of hospitalization, the need for ureteral stent insertion, residual fragments, and subjective evaluation of the lithotripsy environment visualization. Results: The best results were highlighted in Group 3 for almost all evaluated parameters. Significant improvements were indicated in terms of stone-free rates. Conclusions: Additional large studies are needed to support these initial results, but preliminary data indicate a valuable advantage for every urologist who treats urolithiasis.

Association between triglyceride-glucose index and risk of kidney stone: a Chinese population-based case-control study

OBJECTIVE

To investigate the association between the triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance and the risk of kidney stones (KSs) in a Chinese population.

DESIGN

Case-control study.

SETTING

Three Physical Examination Centers in Shanghai, China, between January 2020 and December 2022.

PARTICIPANTS

A total of 117 757 Chinese adults underwent health check-ups during the study period.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association between the TyG index and the risk of KS was assessed using multivariable logistic regression analysis. The dose-response relationship between the TyG index and KS risk was evaluated with a restricted cubic spline (RCS) analysis. Stratified analyses were conducted to explore whether factors such as age, sex, obesity, hypertension and diabetes modify the association between the TyG index and KS risk.

RESULTS

Out Of the 117 757 participants, 11 645 (9.9%) were diagnosed with KS using ultrasound. Individuals with KS had significantly higher TyG values than controls (p<0.001). The multivariable-adjusted ORs for KS increased across TyG quartiles, with the highest quartile showing an OR of 1.28 (95% CI 1.20 to 1.36) compared with the lowest quartile. Each SD increase in the TyG index was associated with a 10% higher risk of KS (OR: 1.10, 95% CI 1.08 to 1.13). RCS analysis revealed a significant positive and linear association between TyG index and KS (p overall<0.001, p non-linear=0.136). The positive association persisted across the subgroup and sensitivity analyses.

CONCLUSIONS

The TyG index was positively associated with the risk of prevalent KS, suggesting that insulin resistance may be a risk factor for KS in the Chinese population.

Discovery of l-Lysine Dioxalate (LH1513) as a Novel Inhibitor of Calcium Oxalate Crystallization for Hyperoxaluria

Hyperoxaluria is caused by increased urinary excretion of oxalate leading to the formation of calcium oxalate (CaOx) stones. The lack of effective management strategies for hyperoxaluria prompted us to investigate molecular mimics as stone inhibitors, a strategy that we previously used successfully to discover small molecule inhibitors of l-cystine crystallization for the prevention of l-cystine stone formation in cystinuria. Herein, we report the discovery of l-lysine dioxalate (LH1513), a novel dioxamate derivative, as a more potent inhibitor of CaOx crystallization than citrate and pyruvate. Such inhibition was corroborated by in situ atomic force microscopy (AFM) measurements of crystal growth rates at the microscopic length scale. A triester prodrug of LH1513 was found to have sufficient oral bioavailability for a preliminary in vivo study demonstrating efficacy in preventing urinary CaOx crystal formation in an Agxt-knockout mouse model for hyperoxaluria.

Characteristics and Yield of Modern Approaches for the Diagnosis of Genetic Causes of Kidney Stone Disease

BACKGROUND

Kidney stone disease (KSD) is characterized by an increasing prevalence worldwide, representing an important clinical issue and a financial burden for healthcare systems. A KSD-causing monogenic variant is traditionally expected in up to 30% of children and 1-5% of adults forming stones, confirmed by a strong connection between a positive family history and KSD. The insufficient use of genetic testing in these patients is associated with a lack of perceived benefit and a scarce awareness of inherited kidney diseases. Genetic testing has important practical implications, such as the possibility of earlier diagnoses, familial counseling, and tailored therapy, based on the evaluation of fine-mapped pathogenic variants. Our aim is to analyze the current evidence on genetic testing in KSD patients to whom genetic tests were applied without strict a priori selection criteria, to provide an overview of its diagnostic yield and factors potentially affecting it (such as the age of KSD onset, a familial history of KSD, consanguinity, and extrarenal features).

METHODS

A literature review was performed, selecting original articles published in the last 10 years concerning genetic investigations in patients affected by nephrolithiasis or nephrocalcinosis. Available data were subsequently extracted and analyzed.

RESULTS

In total, 13 studies on 1675 patients (77% pediatric populations) were included; 333 patients were determined to be affected by a monogenic disorder, with an overall yield of about 20%. The likelihood of a positive genetic finding was much higher in pediatric (26%) than adult populations (8%). Cystinuria was the most common diagnosis in both populations. After the removal of conditions that could be identified with a stone composition analysis or urinary chemistry investigation, the diagnostic yield dropped to 19% among pediatric patients and below 5% for adults.

CONCLUSIONS

Genetic testing should be considered in KSD pediatric patients and in selected subgroups of adults with suggestive features when a diagnosis is not established after stone examination and blood as well as urine metabolic profiling.

Remnant cholesterol increases the risk of incident kidney stones: a nested case-control study in Chinese adults

Kidney stones pose a significant healthcare burden worldwide. Dyslipidemia is a risk factor for kidney stones, but the relationship between remnant cholesterol (RC) and kidney stone risk is unknown. We aimed to investigate the association between RC and the risk of incident kidney stones. We conducted a nested case-control study based on data from Shanghai Kidney Stone Cohort conducted in Shanghai from December 2018 to February 2023. Propensity score matching was used to select 2550 incident kidney stone cases and 7650 controls from a total of 60,158 adults. Baseline fasting plasma samples were collected to measure RC, which was calculated as total cholesterol minus high-density lipoproteins cholesterol and low-density lipoproteins cholesterol. Multivariable conditional logistic regression and a restricted cubic spline were used to estimate the association between tertiles of RC and kidney stone risk. Subgroup and sensitivity analyses were also performed. The baseline RC of incident kidney stone cases and controls were 0.58 (0.57) and 0.54 (0.55), respectively. Incident kidney stones had much higher baseline RC levels than controls (P < 0.001). Higher baseline RC levels were significantly associated with increased kidney stone risk after adjustment for potential confounders (highest vs. lowest tertile: OR 1.16, 95% CI 1.04-1.30; per 1 mmol/L increase: OR 1.16, 95% CI 1.07-1.26). Restricted cubic spline showed a significant positive and linear dose-response relationship between RC and the risk of developing kidney stones (P-overall = 0.005, P-nonlinear = 0.482). Sensitivity analyses yielded consistent results. Elevated RC levels are associated with a greater risk of incident kidney stones in Chinese adults.

Association Between Gallstone Disease and Kidney Stone Disease: A Systematic Review and Meta-analysis

Background and aims: Gallstone disease (GSD) and kidney stone disease (KSD) have increased due to lifestyle in recent decades. This systematic review and meta-analysis aimed to investigate the association between these two diseases. Methods: A comprehensive electronic database search was conducted before August 25, 2024. This systematic review and meta-analysis included observational studies. The meta-analysis employed a random-effects model to compute the overall summary estimates of the association between GSD and KSD using risk ratios with 95% confidence intervals (CIs) as the primary measure of the effect size. Heterogeneity was evaluated using chi-square tests, the I² statistic, and forest plots. Publication bias was assessed through Begg’s and Egger’s tests. A P value of less than 0.05 was considered statistically significant, and all analyses were performed using Stata 17 software. Results: The meta-analysis included 9 studies encompassing 982847 participants. The pooled analysis revealed a statistically significant association between GSD and KSD, with a risk of 1.78 (95% CI: 1.572.03, P≤0.001). Begg’s and Egger’s tests demonstrated no significant bias (Begg’s test P=0.835, Egger’s test P=0.812). Variables such as study year, sample size, mean age of participants, mean follow-up, and study quality as determined by the Newcastle-Ottawa Scale (NOS) were examined, but none could significantly impact heterogeneity (P>0.10). Conclusion: This systematic review and meta-analysis provide evidence of a significant association between GSD and KSD. Therefore, further investigation into the underlying mechanisms and potential risk factors is necessary.

Evaluating the effectiveness of AI-powered UrologiQ's in accurately measuring kidney stone volume in urolithiasis patients

Kidney stones and urolithiasis are kidney diseases that have a significant impact on health and well-being, and their incidence is increasing annually owing to factors such as age, sex, ethnicity, and geographical location. Accurate identification and volume measurement of kidney stones are critical for determining the appropriate surgical approach, as timely and precise treatment is essential to prevent complications and ensure successful outcomes. Larger stones often require more invasive procedures, and precise volume measurements are essential for effective surgical planning and patient outcomes. This study aimed to compare the ability of artificial intelligence (AI) to detect and measure kidney stone volume via CT-KUB images. CT KUB imaging data were analyzed to determine the effectiveness of AI in identifying the volume of kidney stones. The results were compared with measurements taken by radiologists. Compared with radiologists, the AI had greater accuracy, efficiency, and consistency in measuring kidney stone volume. The AI calculates the volume of kidney stones with an average difference of 80% compared with the volumes calculated by radiologists, highlighting a significant discrepancy that is critical for accurate surgical planning. The results suggest that artificial intelligence (AI) outperforms radiologists' manual calculations in measuring kidney stone volume. By integrating AI with kidney stone detection and treatment, there is potential for greater diagnostic precision and treatment effectiveness, which could ultimately improve patient outcomes.

A nomogram to predict "pure" vs. "mixed" uric acid urinary stones

PURPOSE

Uric acid stones (UAS) can be treated non-invasively by oral chemolysis. However, it is crucial to identify individuals who are most likely to benefit from this approach, specifically, patients with pure UAS. The aim of this study was to develop a nomogram that can differentiate between pure and mixed UAS.

METHODS

A retrospective analysis of demographic, clinical and stone composition data of patients with a predominant UAS composition (≥ 50%) treated between 2014 and 2022.

RESULTS

A total of 135 patients were included in the analysis, 37.8% had mixed UAS (50-90% UA) and 62.2% had pure UAS (≥ 95% UA). The mean stone density and the percentage of radiopaque stones in the pure UAS group were significantly lower than those in the mixed UAS group (450 Hounsfield Units [HU] vs. 600 HU, and 24% vs. 58%, respectively). A stepwise multivariate logistic regression revealed that lower stone density, bigger size, decreased stone opacity and older age are predictive variables for pure UAS. Accordingly, a nomogram was generated with a receiver operating characteristic (ROC) curve that showed an area under the curve (AUC) of 0.78. A patient with a total score of 156 has a probability of > 95% for pure UAS.

CONCLUSION

Imaging and demographic data can be used to identify patients with pure UAS. The nomogram may be useful for counseling patients regarding oral chemolysis. Future validation of the nomogram with a different data set is required to assess its efficacy.

Artificial intelligence versus human touch: can artificial intelligence accurately generate a literature review on laser technologies?

PURPOSE

To compare the accuracy of open-source Artificial Intelligence (AI) Large Language Models (LLM) against human authors to generate a systematic review (SR) on the new pulsed-Thulium:YAG (p-Tm:YAG) laser.

METHODS

Five manuscripts were compared. The Human-SR on p-Tm:YAG (considered to be the "ground truth") was written by independent certified endourologists with expertise in lasers, accepted in a peer-review pubmed-indexed journal (but not yet available online, and therefore not accessible to the LLMs). The query to the AI LLMs was: "write a systematic review on pulsed-Thulium:YAG laser for lithotripsy" which was submitted to four LLMs (ChatGPT3.5/Vercel/Claude/Mistral-7b). The LLM-SR were uniformed and Human-SR reformatted to fit the general output appearance, to ensure blindness. Nine participants with various levels of endourological expertise (three Clinical Nurse Specialist nurses, Urology Trainees and Consultants) objectively assessed the accuracy of the five SRs using a bespoke 10 "checkpoint" proforma. A subjective assessment was recorded using a composite score including quality (0-10), clarity (0-10) and overall manuscript rank (1-5).

RESULTS

The Human-SR was objectively and subjectively more accurate than LLM-SRs (96 ± 7% and 86.8 ± 8.2% respectively; p < 0.001). The LLM-SRs did not significantly differ but ChatGPT3.5 presented greater subjective and objective accuracy scores (62.4 ± 15% and 29 ± 28% respectively; p > 0.05). Quality and clarity assessments were significantly impacted by SR type but not the expertise level (p < 0.001 and > 0.05, respectively).

CONCLUSIONS

LLM generated data on highly technical topics present a lower accuracy than Key Opinion Leaders. LLMs, especially ChatGPT3.5, with human supervision could improve our practice.

SGLT2 Inhibitors and Their Effect on Urolithiasis: Current Evidence and Future Directions

Urolithiasis (UL) is increasingly prevalent due to rising cardiorenometabolic diseases, posing significant management challenges despite advances in urological techniques. Sodium-glucose cotransporter-2 (SGLT2) inhibitors, primarily used for type 2 diabetes mellitus, chronic kidney disease, and heart failure, have emerged as a potential novel approach for UL treatment. These inhibitors may help reduce the risk of urolithiasis, particularly in patients with diabetes, by improving glycemic control and altering urinary chemistry, which are crucial factors in stone formation. However, the changes in urinary composition induced by SGLT2 inhibitors might also increase the risk of uric acid stone formation. This review evaluates the potential of SGLT2 inhibitors in managing UL, highlighting both the benefits and the risks. While these inhibitors show promise in reducing new and recurrent urinary stones in patients with diabetes, data on their effects in patients without diabetes who form stones are limited. Current human evidence largely comes from post hoc analyses of randomized controlled trials (RCTs) and large-scale database studies, with only one study providing detailed stone composition data. Experimental studies in animal models and cell lines have focused on calcium oxalate (CaOx) stones, showing that SGLT2 inhibitors specifically target CaOx stone formation and related renal inflammation. Although primarily studied for CaOx stones, their potential impact on other calcium-containing stones, such as calcium phosphate, remains promising. Further research is needed to explore their therapeutic potential and optimize treatment strategies.

Optimizing antigen preparation for oxalyl-CoA decarboxylase enzyme diagnostic kit and ELISA system cutoff determination

The prevalence of kidney stone disease is increasing globally, with calcium oxalate stones being the most common type. Oxalyl-CoA decarboxylase (OXC), an enzyme produced by the gut bacterium Oxalobacter formigenes, plays a crucial role in oxalate metabolism. Deficiencies in OXC activity can lead to the accumulation of oxalate, contributing to kidney stone formation. This study aimed to develop a reliable diagnostic assay for OXC by optimizing antigen production and establishing a cutoff value for an enzyme-linked immunosorbent assay (ELISA). We cloned, expressed, and purified recombinant OXC protein in Escherichia coli BL21(DE3), and generated specific polyclonal antibodies in rabbits. The ELISA system was optimized and validated using serum samples from 40 healthy individuals and 6 patients with oxalate-related disorders. The cutoff value was determined using the formula (M + 2SD), where (M) is the mean and (SD) is the standard deviation of the healthy sample results. The calculated cutoff value of 0.656750 effectively distinguished between healthy and affected individuals, with a sensitivity of 97.5% and a specificity of 83.3%. These findings provide a valuable tool for the early detection and management of oxalate-related disorders, with significant implications for clinical practice.

Osteogenic-Like Microenvironment of Renal Interstitium Induced by Osteomodulin Contributes to Randall's Plaque Formation

Calcium oxalate (CaOx) kidney stones are common and recurrent, lacking pharmacological prevention. Randall's plaques (RPs), calcium deposits in renal papillae, serve as niduses for some CaOx stones. This study explores the role of osteogenic-like cells in RP formation resembling ossification. CaP crystals deposit around renal tubules, interstitium, and blood vessels in RP tissues. Human renal interstitial fibroblasts (hRIFs) exhibit the highest osteogenic-like differentiation potential compared to chloride voltage-gated channel Ka positive tubular epithelial cells, aquaporin 2 positive collecting duct cells, and vascular endothelial cells, echoing the upregulated osteogenic markers primarily in hRIFs within RP tissues. Utilizing RNA-seq, osteomodulin (OMD) is found to be upregulated in hRIFs within RP tissues and hRIFs following osteogenic induction. Furthermore, OMD colocalizes with CaP crystals and calcium vesicles within RP tissues. OMD can enhance osteogenic-like differentiation of hRIFs in vitro and in vivo. Additionally, crystal deposits are attenuated in mice with Omd deletion in renal interstitial fibroblasts following CaOx nephrocalcinosis induction. Mechanically, a positive feedback loop of OMD/BMP2/BMPR1A/RUNX2/OMD drives hRIFs to adopt osteogenic-like fates, by which OMD induces osteogenic-like microenvironment of renal interstitium to participate in RP formation. We identify OMD upregulation as a pathological feature of RP, paving the way for preventing CaOx stones.

Demonstrating the Efficacy of Dual Energy Computer Tomography with Gemstone Spectral Imaging Software to Determine Mixed and Single Composition ex vivo Urolithiasis

Objective

To assess the capability of determining the mixed chemical composition of urinary stones using spectral imaging properties of Dual Energy Computed Tomography (DECT) Gemstone Spectral Imaging (GSI) software.

Material and Methods

Twenty-six single and 24 mixed composition ex vivo urinary stones with known chemical composition determined by Fourier-transform infrared spectroscopy (FTIR) prior to this project were scanned with DECT imaging and GSI in vitro. The major components of the stones included Uric Acid (UA), Calcium Oxalate (CaOx), Calcium Phosphate (CaP), Magnesium Ammonium Phosphate (MAP), and Cystine (Cys). A histogram to display the distribution of the effective atomic number (Z-eff) of each pixel of the tested area, spectral curve (40-140 keV, with 10 keV interval) and Hounsfield Units (HU) of each stone scanned was provided with analysis of monochromatic images at 140 keV in the axial plane.

Results

The overall pooled sensitivity, specificity, and accuracy of DECT for identifying major stone composition were 0.802, 0.831, and 0.807, respectively, with a 95% confidence interval. Accuracy was 100% for identifying UA and Cys stones.

Conclusion

DECT is a superior imaging modality when compared to low dose computed tomography kidney ureter bladder scans. It allows for improved characterization of major components of urinary stones, in an accurate, non-invasive approach to pre-treatment. This can translate to urologists having greater confidence in determining patient suitability for medical or surgical management of their renal stones, in clinical practice.

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

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

Association between metabolic dysfunction-associated steatotic liver disease and risk of urolithiasis: an updated systematic review and meta-analysis

Epidemiological studies have reported an association between metabolic dysfunction-associated steatotic liver disease (MASLD) and the risk of urolithiasis. However, the magnitude of the risk and whether this risk varies with the severity of MASLD remains uncertain. We performed a meta-analysis of observational studies to quantify the magnitude of the association between MASLD and urolithiasis. We systematically searched PubMed, Scopus, and Web of Science from database inception to March 31, 2024, using predefined keywords to identify relevant observational studies in which imaging methods or survey questionnaires diagnosed MASLD and urolithiasis. Meta-analysis was performed using random-effects modelling. We identified seven cross-sectional studies and one prospective cohort study with aggregate data on 248,936 adults from different countries. MASLD was significantly associated with an increased risk of prevalent urolithiasis (pooled random-effects odds ratio 1.87, 95% CI 1.34-2.60; I2 = 91%). This association remained significant in those studies whose results were adjusted for age, sex, ethnicity, obesity, diabetes, and other potential confounders. There was a positive graded association between the ultrasonographic severity of MASLD and urolithiasis. Meta-analysis of the single prospective cohort study showed that MAFLD was not associated with risk of developing incident urolithiasis (pooled random-effects hazard ratio 1.08, 95% CI 0.90-1.30), although a significant association was reported in men. Sensitivity analyses did not modify these findings. The funnel plot did not reveal any significant publication bias. This updated meta-analysis provides evidence for a significant association between MASLD and the presence of urolithiasis. Whether MASLD is associated with a higher risk of developing incident urolithiasis remains to be established.

Risk factors for nephrolithiasis formation: an umbrella review

OBJECTIVE

Nephrolithiasis is prevalent and burdensome worldwide. At present, evidence on the risk factors for nephrolithiasis is unconsolidated and the associations remain uncertain. The authors systematically evaluate the robustness of the meta-analytic evidence and aid more reliable interpretations of the epidemiological relationships.

METHODS

The authors conducted a comprehensive review of the meta-analyses, screened the included studies with the aid of the AMSTAR 2 evaluation tool, and then used R (4.1.1) software to perform data analysis to evaluate the association between candidate risk factors and kidney stones, and evaluated the credibility of the evidence of the association between risk factors and kidney stones according to the GRADE classification, and finally obtained the strength and effectiveness of the association.

RESULTS

The authors finally included 17 meta-analyses regarding 46 risk factors, 34 of which (73.9%) showed statistically significant association with nephrolithiasis. Among the significant associations, the authors found that waist circumference, BMI, dietary intake and fructose intake were positively correlated with the occurrence and development of nephrolithiasis. Caffeine, dietary fiber and DASH-diet showed a tendency to reduce kidney stones. Interestingly, calcium supplementation, dietary calcium, and vitamin D, which are widely believed to be responsible for stone formation, made no difference or even reduced the risk of nephrolithiasis.

CONCLUSIONS

The authors' study demonstrates the suggestive causal (central obesity, type 2 diabetes, gout, dietary sodium, fructose intake and higher temperatures) risk factors of nephrolithiasis. The authors also demonstrate the suggestive causal (coffee/alcohol/beer intake, dietary calcium and DASH-diet) protective factors of nephrolithiasis. To provide epidemiological basis for the treatment and prevention of nephrolithiasis.

Unraveling the association of bacteria and urinary stones in patients with urolithiasis: an update review article

Urinary stone disease (USD) is a prevalent urological condition, ranking as one of the most common urinary tract disorders globally. Various risk factors influence the formation of kidney stones, and recent research indicates a rising prevalence of urolithiasis worldwide, particularly in developing countries. While the morbidity associated with urinary stones has decreased in recent years, long-term complications such as stone recurrence, kidney failure, and uremia continue to burden patients. Understanding the etiologies of urolithiasis, including the role of bacteria, is crucial as they can contribute to stone recurrence. The incidence of urinary tract infection (UTI) stones can be attributed to specific infectious risk factors, socio-demographic factors, and comorbid metabolic disorders. This review article explores the emerging evidence suggesting the involvement of bacteria in USD. It discusses the potential role of microorganisms in non-infection stones and highlights the association between UTIs and urolithiasis. Furthermore, it surveys the relationship between kidney stones and recurrent UTIs and the formation of bacterial biofilms in UTIs. Considering various risk factors, including biochemical stone analysis and the presence of bacteria, is essential for treating patients with infectious stones optimally. This review aims to provide an updated understanding of the association between bacteria and urinary stones in patients with urolithiasis, shedding light on the pathophysiology of urinary stone formation, urinary stone characteristics, and the urinary microbiome in urinary stones.

Phytate Effects on Incomplete Distal Renal Tubular Acidosis

Background: Adults who have incomplete distal renal tubular acidosis (dRTA) may present with recurrent urolithiasis due to metabolic acidosis, leading to bone resorption, which in turn causes hypercalciuria and urine alkalinization (pH > 6.0). Oral potassium citrate is the most commonly used treatment for dRTA, but some patients cannot tolerate this treatment. The objective of this single-arm study was to evaluate the effect of phytate, an inhibitor of bone resorption, on calciuria of patients with incomplete dRTA. Methods: The calciuria levels of 16 patients who had incomplete dRTA with urolithiasis and could not tolerate potassium citrate treatment were recorded before (baseline) and after 6 months of treatment with oral calcium magnesium phytate (380 mg every 12 h). There were no dietary modifications or other treatments. Results: The baseline calciuria was 317 ± 81 mg/24 h and the level after 6 months was 221 ± 38 mg/24 h (p < 0.005). Conclusions: Our results suggest that calcium magnesium phytate should be considered as an alternative or adjunctive treatment for hypercalciuria in patients with incomplete dRTA.

Trajectories of body mass index and incident kidney stone disease: a prospective cohort study in Chinese young adults

The present study aims to explore the potential changing trajectory patterns of body mass index (BMI) for Chinese young adults and identify the relationship of BMI trajectory patterns with kidney stone disease (KSD) incidence. Latent class growth analysis was used to identify distinct trajectories of BMI during young adulthood. Cox proportion hazard models were conducted to explore the association between the BMI trajectory group memberships and incident KSD. Subgroup and sensitivity analyses were undertaken to test the robustness of the findings. In total, 2,966 young adults who attended at least three annual check-ups from 2014 to 2021 without KSD at baseline were enrolled in the cohort analysis. Three district BMI trajectories were identified for young adults, labeled as low-stable in normal BMI (28.5%), medium-rising to high BMI (67.4%), and rapid-rising to high BMI (4.1%). Compared with the low-stable in normal BMI group, Hazard ratios (HRs) of the rapid-rising and medium-rising to high BMI groups were 3.19 (95% CI: 1.54-6.63) and 1.78 (95% CI: 1.08-2.92) after adjusting the covariates. The cumulative incidence curves likewise illustrated that young adults in the rapid-rising to high BMI group had the highest risk of developing KSD compared to the other two groups. The rapid BMI growth trajectories during young adulthood were identified to be independently associated with a higher risk of KSD. The findings supplied novel insights that monitoring the BMI changing pattern may be favorable to early intervention of KSD during young adulthood.