Cross-talk between renal lithogenesis and atherosclerosis: an unveiled link between kidney stone formation and cardiovascular diseases

The atherogenic index of plasma increases the risk of incident kidney stones: a nested case-control study in Chinese adults

OBJECTIVE

To investigate the association between atherogenic index of plasma (AIP) and risk of incident kidney stones.

METHODS

A nested case-control study was conducted using data from the Shanghai Kidney Stone Cohort from December 2018 to February 2023. Kidney stones were ascertained by ultrasound. Propensity score matching selected 2,550 patients with incident kidney stones and 5,100 controls from a total of 64,121 adults. Baseline fasting plasma samples were collected to measure the AIP, defined as the logarithm of the ratio triglycerides to high-density lipoprotein cholesterol. A multivariable conditional logistic regression model and restricted cubic spline were applied to examine the association between the AIP and the risk of incident kidney stones.

RESULTS

The baseline AIP values of the incident kidney stone patients and controls were 0.98 (0.67) and 0.91 (0.65), respectively. Patients with incident kidney stones had much higher baseline AIP levels than controls (p < 0.001). Participants in the highest AIP quartile had a 29% greater risk of developing kidney stones. Moreover, each increase in the standard deviation of the AIP was associated with a 10% greater risk of nephrolithiasis. A restricted cubic spline showed a significant positive and linear correlation between the AIP and the risk of developing kidney stones (P-overall = 0.040, P-nonlinear = 0.923). These findings remained robust in sensitivity analyses.

CONCLUSIONS

A higher AIP is associated with a greater risk of incident kidney stones.

Association of cardiovascular-kidney-metabolic syndrome stages with kidney stone prevalence: a population-based analysis of NHANES 2007-2020

BACKGROUND

The prevalence of kidney stones (KSs) has been increasing globally, and their association with cardiovascular disease and metabolic syndrome suggests a shared underlying pathophysiology. However, the impact of different stages of cardiovascular-kidney-metabolic (CKM) syndrome on KS prevalence remains unclear.

OBJECTIVE

This study aimed to investigate the association between the stages of CKM syndrome and the prevalence of KS in a nationally representative sample of adults in the USA.

METHODS

A total of 15 568 participants aged ≥20 years were included in the National Health and Nutrition Examination Survey 2007-2020 fasting subsample. CKM syndrome stages (0-4) were defined based on the 2023 American Heart Association Presidential Advisory on CKM Health. The KS history was determined using self-reported data. Multivariable logistic regression models were used to assess the association between the CKM syndrome stage and KS prevalence.

RESULTS

Of the 15 568 participants, 1501 (9.64%) reported a history of KS. The KS prevalence increased progressively with advancing CKM stage, rising from 5.10% in stage 0 to 16.55% in stage 4 (p<0.001). In the fully adjusted model, the ORs for KS were 1.18 (95% CI 0.83-1.68) for stage 1, 1.72 (95% CI 1.28 to 2.32) for stage 2, 2.00 (95% CI 1.29 to 3.10) for stage 3 and 2.36 (95% CI 1.64 to 3.40) for stage 4, compared with stage 0 (P for trend <0.001). Stratified analyses revealed no significant interactions between age, sex, race/ethnicity or other subgroups.

CONCLUSION

This study demonstrated a significant stepwise increase in KS prevalence with the advancing stages of CKM syndrome. These findings highlight the importance of monitoring and managing CKM syndromes to mitigate the risks of KS.

Association between ZJU index and kidney stone prevalence in the Chinese adult population: a retrospective propensity score-matched analysis

The study aimed to explore the association between the ZJU (Zhejiang University) index and the prevalence of kidney stones in Chinese adults. Electronic health records of individuals undergoing routine physical examinations at Wuhu Second People's Hospital between January 2021 and June 2024 were retrospectively analyzed. Participants were divided into kidney stone recurrence and non-recurrence groups. Data on biochemical parameters, hypertension, and diabetes history were collected, and group differences were assessed using the chi-square test or Kruskal-Wallis rank-sum test. Logistic regression, propensity score matching, and dose-response curve modeling were used to evaluate the relationship between the ZJU index and kidney stone prevalence. Among 5,104 participants aged over 18 years, 462 were diagnosed with kidney stones. After adjusting for confounders, a higher ZJU index was identified as an independent risk factor for kidney stone prevalence (odds ratio [OR] = 1.05, 95% confidence interval [CI]: 1.02-1.08). Propensity score-matched analysis further confirmed this association (OR = 1.09, 95% CI: 1.04-1.13). Dose-response analysis revealed a positive linear relationship between the ZJU index and kidney stone recurrence. These findings suggest that elevated ZJU index levels are associated with a higher prevalence and recurrence of kidney stones, highlighting its potential as a clinical tool for identifying and managing at-risk patients.

Life's Essential 8 and kidney stones in US adults: mediating roles of HDL and insulin resistance

BACKGROUND

The rising incidence of kidney stones underscores the imperative to devise effective preventive measures. While a robust association between cardiovascular disease (CVD) and kidney stones exists, the current research landscape lacks investigations between cardiovascular health (CVH) and kidney stones. This study aims to explore the association between CVH, assessed by Life's Essential 8 (LE8), and kidney stones, with the role of blood lipids and insulin resistance in this relationship.

METHODS

The study included 19,942 adults aged ≥20 from the National Health and Nutrition Examination Survey of the US from 2007 to 2018. LE8, measuring CVH, includes four behavior and four factor metrics. Participants were categorized into high, moderate, and low CVH levels according to LE8 Scores: 80-100, 50-79, and 0-49, respectively. Kidney stones cases were identified through interviews and self-reported records. Weighted multivariate linear regressions, weighted logistic regressions, restricted cubic spline (RCS) analysis, mediation analyses, and sensitivity analyses were conducted.

RESULTS

In the fully adjusted logistic model, 10-point increase in LE8 Score exhibited a significant 19% reduction in kidney stones prevalence (OR=0.81, 95% CI: 0.77-0.85). The RCS confirmed the nonlinear association between LE8 Score and kidney stones (P for non-linearity: 0.004). Mediation analyses showed the mediation proportions of 19.62%, 24.26%, and 27.82% for high-density lipoprotein (HDL), insulin resistance (HOMA-IR), and serum insulin, respectively. The mediation proportions of the HOMA-IR-HDL and serum insulin-HDL pathways were 6.62% and 5.96%, respectively.

CONCLUSIONS

This study illuminates a negative association between CVH and kidney stones, providing an effective strategy for kidney stones prevention.

Management of hypertension addressing hyperuricaemia: introduction of nano-based approaches

Uric acid (UA) levels in blood serum have been associated with hypertension, indicating a potential causal relationship between high serum UA levels and the progression of hypertension. Therefore, the reduction of serum UA level is considered a potential strategy for lowering and mitigating blood pressure. If an individual is at risk of developing or already manifesting elevated blood pressure, this intervention could be an integral part of a comprehensive treatment plan. By addressing hyperuricaemia, practitioners may subsidize the optimization of blood pressure regulation, which illustrates the importance of addressing UA levels as a valuable strategy within the broader context of hypertension management. In this analysis, we outlined the operational principles of effective xanthine oxidase inhibitors for the treatment of hyperuricaemia and hypertension, along with an exploration of the contribution of nanotechnology to this field.

Exploring the molecular interactions between nephrolithiasis and carotid atherosclerosis: asporin as a potential biomarker

Increasing evidence suggested nephrolithiasis has a close linkage with carotid atherosclerosis (CAS), with Randall's plaque (RP) being a precursor to kidney stones. Our study aimed to examine the crosstalk genes and potential molecular mechanisms between RP and CAS. We obtained microarray data for RP and CAS from the Gene Expression Omnibus (GEO) and used weighted gene co-expression network analysis (WGCNA) and differential gene expression (DEG) analysis to identify shared genes. By integrating WGCNA and DEG analysis, Asporin (ASPN) was identified as the key gene connecting RP and CAS, with its diagnostic potential assessed via a receiver operating characteristic (ROC) curve. Immune infiltration studies showed a significant correlation between ASPN and various immune cells in RP and CAS. ASPN was found to be less expressed in RP and CAS tissues compared to normal tissues, as confirmed by immunohistochemistry (IHC) and quantitative reverse-transcription PCR (qRT-PCR). The rat model confirmed the human tissue findings. ASPN can elucidate the shared pathogenic mechanisms underlying the two conditions, including immune response and osteoblast differentiation.

Association between Urinary Flora and Urinary Stones

BACKGROUND

Urinary system stones are a common clinical disease, with significant differences in incidence and recurrence rates between different countries and regions. The etiology and pathogenesis of urinary system stones have not been fully elucidated, but many studies have found that some bacteria and fungi that are difficult to detect in urine constitute a unique urinary microbiome. This special urinary microbiome is closely related to the occurrence and development of urinary system stones. By analyzing the urinary microbiome and its metabolic products, early diagnosis and treatment of urinary system stones can be carried out.

SUMMARY

This article reviews the relationship between the urinary microbiome and urinary system stones, discusses the impact of the microbiome on the formation of urinary system stones and its potential therapeutic value, with the aim of providing a reference for the early diagnosis, prevention, and treatment of urinary system stones.

KEY MESSAGES

(i) Urinary stones are a common and recurrent disease, and there is no good way to prevent them. (ii) With advances in testing technology, studies have found that healthy human urine also contains various types of bacteria. (iii) Is there a potential connection between the urinary microbiota and urinary stones, and if so, can understanding these connections offer fresh perspectives and strategies for the diagnosis, treatment, and prevention of urinary stones?

Association of low-dose aspirin use for primary prevention with self-reported kidney stones prevalence: a cross-sectional study

OBJECTIVE

To investigate the association between low-dose aspirin use for primary prevention and self-reported kidney stones prevalence in the 40-79 years old population.

METHODS

We conducted a cross-sectional study based on the United States population data from the National Health and Nutrition Examination Survey 2011-2018. Baseline demographical and clinical data were collected. The univariate and multivariate regression was performed to identify confounding factors and assess the relationship between aspirin use for primary prevention and the prevalence of self-reported kidney stones. A propensity-score matching was used to identify patients with similar baseline characteristics to adjust for the bias caused by confounding factors.

RESULTS

A total of 10,256 low-dose aspirin-use participants were included in this study. 10.4% of participants reported a history of kidney stones, and 18.5% reported a continuous use of low-dose prophylactic aspirin. Multivariate logistic regression analysis showed that low-dose preventive aspirin use had significantly increased the odds of self-reported kidney stones (OR = 1.245; 95% CI: 1.063-1.459; p = 0.007). In subgroup analysis, this finding was primarily limited to males (OR = 1.311), non-hypertensive participants (OR = 1.443), diabetic participants (OR = 1.380), and older (60 ≤ Age < 80) (OR = 1.349). The propensity-score matched analyses supported this result after adjusting for the bias caused by potential confounders (OR = 1.216; 95% CI: 1.011-1.462; p = 0.038).

CONCLUSION

In this study, there exists a significant relationship between low-dose aspirin for primary prevention and self-reported kidney stones, primarily among males, no hypertensive participants, diabetics, or older adults. Further studies are needed to elucidate the mechanisms underlying these findings in the future.

Nephrolithiasis is associated with the severity of coronary artery calcification, but not with coronary artery stenosis

PURPOSE

Emerging data have indicated that nephrolithiasis is possibly associated with subclinical coronary artery disease (CAD). Considering that a significant proportion of obstructive CAD in non-elderly individuals occurs in those without detectable calcium score (CACS), this study aimed to investigate whether nephrolithiasis is still associated with CAD as assessed by coronary computed tomography (CT)-derived luminal stenosis [using Gensini score (GS)].

METHODS

A total of 1170 asymptomatic adults without known CAD who underwent health examinations were recruited. Nephrolithiasis was assessed using abdominal ultrasonography (US). Individuals with a self-reported stone history, but no evidence of nephrolithiasis were excluded. The CACS and GS were measured using 256-slice coronary CT.

RESULTS

Nearly half of these patients had a CACS > 0 (48.1%), and a higher prevalence of nephrolithiasis was observed than in those who had zero CACS (13.1% vs. 9.7%). However, no significant intergroup difference in GS was detected. A greater proportion of stone formers than non-stone formers had a higher risk category, whereas no significant difference was noted in Gensini category. Multiple linear regression analyses showed that the CACS independently predicted the presence of nephrolithiasis after adjustment. Importantly, we found that stone formers had a nearly threefold higher risk than non-stone formers of developing severe coronary calcification (CAC > 400).

CONCLUSIONS

Nephrolithiasis was significantly associated with coronary artery calcification presence and severity, but not coronary luminal stenosis in patients without known CAD. Accordingly, the relationship between stone disease and CAD remains controversial, and additional studies are imperative to validate these findings.

Increased renal uptake and urine excretion of oxidized LDL is possibly associated with formation of large calcium oxalate nephrolithiasis: a preliminary study

PURPOSE

Growing evidence have suggested an association between nephrolithiasis and cardiovascular disease (CVD) with unclear mechanism. Oxidized low-density lipoproteins (oxLDL) induces atherosclerosis and was found to be the possible link between these two diseases. Our study aimed to examine the serum, urine and kidney expression of oxLDL in relation to large calcium oxalate (CaOx) renal stone disease.

METHODS

A total of 67 large CaOx dominant renal stone patients and 31 stone-free controls were enrolled in the prospective case-control study. All participants were without known CVD history. Serum, urine, and kidney biopsy were collected before and during percutaneous nephrolithotomy, respectively. Enzyme-linked immunosorbent assays were used to assess serum and urine oxLDL, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), and high-sensitivity C-reactive protein (hsCRP).

RESULTS

There was no significantly difference in circulating oxLDL, but serum hsCRP was significantly near two-fold higher in nephrolithiasis patients. Serum hsCRP was also correlated with stone maximal length. Urine oxLDL was significantly higher in the nephrolithiasis group and correlated with serum hsCRP and stone maximal length. Increased oxLDL uptake in kidney was found in nephrolithiasis patients, whereas no significantly renal expression of oxLDL was observed in controls.

CONCLUSIONS

The renal uptake of oxLDL with increased oxLDL excretion from large CaOx renal stone formers, independent of increased circulating oxLDL, is a novel pathological finding in kidney stone disease and brings attention to the possible involvement of renal steatosis in the process of urolithiasis formation.

Metabolic evaluation of high-risk stone formers: a retrospective study

Background

The purpose of this study was to assess the metabolic abnormalities in high-risk stone formers.

Methods

This was a retrospective observational study done at Tribhuvan University Teaching Hospital, Nepal, over 1-year period. High-risk stone formers were identified and were evaluated with serum chemistries and 24-h urinary chemical evaluation. Stone analysis was also included whenever available. Common metabolic abnormalities and stone analysis results were reported and compared with different studies. Continuous variables were expressed as mean ± SD. Categorical variables were expressed as percentage and proportions.

Results

During 1 year of period, sixty-five patients had undergone extensive metabolic evaluation, but complete data were available for only forty-six patients. Of the total patients (n = 46), 63% were male (n = 29) and rest (36.9%) were female. Mean age of patients was 34.4 ± 15.1 years. Common reasons for metabolic evaluation were multiple stones (40%), bilateral stones (27%), recurrent stones (17%) and others (16%). Most common stone type was mixed stone with predominant composition being calcium oxalate mono- and dihydrate (62.9%). Twenty-four-hour urinary metabolic evaluation showed hyperoxaluria (32.6%) as most common abnormalities followed by hypocitraturia (21.7%) and hypocalciuria (21.7%).

Conclusion

Hyperoxaluria and hypocitraturia are common metabolic abnormalities in our patients. These findings help in counselling dietary measures to patients.

Risk factors of urinary calculi in men with gout

OBJECTIVE

To investigate risk factors of urinary calculi in men with gout.

METHOD

A study was conducted at a tertiary hospital in Beijing from October 2016 to January 2020. Male gouty patients were included. Logistic regression was used to establish the association between patients' characteristics and urinary stone disease. A cluster analysis was performed to identify distinct phenotypes of gout based on nine common comorbidities.

RESULT

The prevalence of calculi was 23.6% among 454 patients. Longer disease courses and comorbid dyslipidemia were associated with an increased risk of urinary calculi, with an OR of 2.76 (95% CI 1.40-5.64) (p = 0.004) for patients with a disease course of 10 years or longer compared with those with a disease course of gout shorter than 1 year, and an OR of 1.71 (95% CI 1.04-2.88) (p = 0.039) for patients with dyslipidemia. Three clinical phenotypes were recognized. Cluster C1 consists of patients with large body mass index, dyslipidemia, and abnormal liver function. The prevalence of stone was 23.2%. Patients in cluster C2 had fewer comorbidities and the lowest stone risk (13.5%). Cluster C3 had more cardiovascular comorbidities and the highest prevalence of stone (47.1%).

CONCLUSION

Longer disease course and dyslipidemia contribute to stone risk in men with gout. Three distinct phenotypes represent distinct pathophysiological mechanisms underlying stone occurrence, which would help us to optimize gout management. Key points • Patients with gout have higher risks for urinary stones. This study found that longer disease courses and comorbid dyslipidemia were associated with an increased risk of urinary calculi in largely untreated young men with uncontrolled gout. • This study reveals three distinct phenotypes of gout based on comorbidities. Among all, the group with more cardiovascular comorbidities has the highest prevalence of stones.

Modification effect of changes in cardiometabolic traits in association between kidney stones and cardiovascular events

Backgrounds

Whether longitudinal changes in metabolic status influence the effect of kidney stones on cardiovascular disease (CVD) remains unclarified. We investigated the modification effect of status changes in metabolic syndrome (MetS) in the association of kidney stones with risk of incident CVD events.

Methods

We performed a prospective association and interaction study in a nationwide cohort including 129,172 participants aged ≥ 40 years without CVDs at baseline and followed up for an average of 3.8 years. Kidney stones information was collected by using a questionnaire and validated by medical records. The repeated biochemical measurements were performed to ascertain the metabolic status at both baseline and follow-up.

Results

4,017 incident total CVDs, 1,413 coronary heart diseases (CHDs) and 2,682 strokes were documented and ascertained during follow-up. Kidney stones presence was significantly associated with 44%, 70% and 31% higher risk of CVDs, CHDs and stroke, respectively. The stratified analysis showed significant associations were found in the incident and sustained MetS patients, while no significant associations were found in the non-MetS at both baseline and follow-up subjects or the MetS remission ones, especially in women. For the change status of each single component of the MetS, though the trends were not always the same, the associations with CVD were consistently significant in those with sustained metabolic disorders, except for the sustained high blood glucose group, while the associations were consistently significant in those with incident metabolic disorders except for the incident blood pressure group. We also found a significant association of kidney stone and CVD or CHD risk in the remain normal glucose or triglycerides groups; while the associations were consistently significant in those with incident metabolic disorders except for the incident blood pressure group. We also found a significant association of kidney stone and CVD or CHD risk in the remain normal glucose or triglycerides groups.

Conclusions

A history of kidney stones in women with newly developed MetS or long-standing MetS associated with increased risk of CVD. The mechanisms link kidney stones and CVD risk in the metabolic and non-metabolic pathways were warranted for further studies.

Pediatric Mineral and Bone Disorder of Chronic Kidney Disease and Cardiovascular Disease

Chronic kidney disease is common and causes significant morbidity including shortened lifespans and decrease in quality of life for patients. The major cause of mortality in chronic kidney disease is cardiovascular disease. Cardiovascular disease within the chronic kidney disease population is closely tied with disordered calcium and phosphorus metabolism and driven in part by renal bone disease. The complex nature of renal, bone, and cardiovascular diseases was renamed as mineral and bone disorder of chronic kidney disease to encompass how bone disease drives vascular calcification and contributes to the development of long-term cardiovascular disease, and recent data suggest that managing bone disease well can augment and improve cardiovascular disease status. Pediatric nephrologists have additional obstacles in optimal mineral and bone disorder of chronic kidney disease management such as linear growth and skeletal maturation. In this article, we will discuss cardiovascular and bone diseases in chronic kidney disease and end-stage kidney disease patients with a focus on pediatric issues and concerns.

Plasma oxalic acid and cardiovascular risk in end-stage renal disease patients: a prospective, observational cohort pilot study

BACKGROUND/AIMS

It was hypothesized that oxalate might be strongly involved in atherogenesis and the inflammatory pathway that could result in an increased risk of cardiovascular disease (CVD) in end-stage renal disease (ESRD) patients. Therefore, this study aimed to address two primary research questions: to characterize the lipid profile and the pattern of pro-inflammatory cytokines according to plasma oxalic acid (POx) concentration in ESRD patients; to evaluate the potential role of elevated POx concentration in the development of CVD risk.

METHODS

A total of 73 participants were enrolled in this prospective, observational cohort pilot study. Among them, there were 50 ESRD patients and 23 healthy volunteers. The lipid profile and the pro-inflammatory cytokines were analyzed according to the distribution of POx concentration into tertiles. After the clinical examination, 29 hemodialysis patients and 21 peritoneal dialysis patients without prevalent CVD were observed for CVD events for 2 years. The Cox regression analysis and a set of different types of sensitivity analyses were used to determine whether elevated POx was associated with an increased risk of CVD.

RESULTS

An increasing trend in the atherogenic lipoprotein fractions and the pro-inflammatory markers as well as a linear decrease in high-density lipoprotein was significantly associated with elevated POx. POx concentration ≥ 62.9 μmol/L was significantly associated with CVD events independently of other examined CVD risk factors.

CONCLUSION

This pilot study firstly demonstrated a potential contribution of POx to atherogenesis, inflammation and CVD risk in ESRD patients.

Dysregulated oxalate metabolism is a driver and therapeutic target in atherosclerosis

Dysregulated glycine metabolism is emerging as a common denominator in cardiometabolic diseases, but its contribution to atherosclerosis remains unclear. In this study, we demonstrate impaired glycine-oxalate metabolism through alanine-glyoxylate aminotransferase (AGXT) in atherosclerosis. As found in patients with atherosclerosis, the glycine/oxalate ratio is decreased in atherosclerotic mice concomitant with suppression of AGXT. Agxt deletion in apolipoprotein E-deficient (Apoe-/-) mice decreases the glycine/oxalate ratio and increases atherosclerosis with induction of hepatic pro-atherogenic pathways, predominantly cytokine/chemokine signaling and dysregulated redox homeostasis. Consistently, circulating and aortic C-C motif chemokine ligand 5 (CCL5) and superoxide in lesional macrophages are increased. Similar findings are observed following dietary oxalate overload in Apoe-/- mice. In macrophages, oxalate induces mitochondrial dysfunction and superoxide accumulation, leading to increased CCL5. Conversely, AGXT overexpression in Apoe-/- mice increases the glycine/oxalate ratio and decreases aortic superoxide, CCL5, and atherosclerosis. Our findings uncover dysregulated oxalate metabolism via suppressed AGXT as a driver and therapeutic target in atherosclerosis.

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.

Excretion of urine extracellular vesicles bearing markers of activated immune cells and calcium/phosphorus physiology differ between calcium kidney stone formers and non-stone formers

BACKGROUNDS

Previous studies have demonstrated that excretion of urinary extracellular vesicles (EVs) from different nephron segments differs between kidney stone formers and non-stone formers (NSFs), and could reflect pathogenic mechanisms of urinary stone disease. In this study we quantified selected populations of specific urinary EVs carrying protein markers of immune cells and calcium/phosphorus physiology in calcium oxalate stone formers (CSFs) compared to non-stone formers (NSFs).

METHODS

Biobanked urine samples from CSFs (n = 24) undergoing stone removal surgery and age- and sex- matched NSFs (n = 21) were studied. Urinary EVs carrying proteins related to renal calcium/phosphorus physiology (phosphorus transporters (PiT1 and PiT2), Klotho, and fibroblast growth factor 23 (FGF23); markers associated with EV generation (anoctamin-4 (ANO4) and Huntington interacting protein 1 (HIP1)), and markers shed from activated immune cells were quantified by standardized and published method of digital flow cytometry.

RESULTS

Urine excretion of calcium, oxalate, phosphorus, and calcium oxalate supersaturation (SS) were significantly higher in CSFs compared to NSFs (P < 0.05). Urinary excretion of EVs with markers of total leukocytes (CD45), neutrophils (CD15), macrophages (CD68), Klotho, FGF23, PiT1, PiT2, and ANO4 were each markedly lower in CSFs than NSFs (P < 0.05) whereas excretion of those with markers of monocytes (CD14), T-Lymphocytes (CD3), B-Lymphocytes (CD19), plasma cells (CD138 plus CD319 positive) were not different between the groups. Urinary excretion of EVs expressing PiT1 and PiT2 negatively (P < 0.05) correlated with urinary phosphorus excretion, whereas excretion of EVs expressing FGF23 negatively (P < 0.05) correlated with both urinary calcium and phosphorus excretion. Urinary EVs with markers of HIP1 and ANO4 correlated negatively (P < 0.05) with clinical stone events and basement membrane calcifications on papillary tip biopsies.

CONCLUSIONS

Urinary excretion of EVs derived from specific types of activated immune cells and EVs with proteins related to calcium/phosphorus regulation differed between CSFs and NSFs. Further validation of these and other populations of urinary EVs in larger cohort could identify biomarkers that elucidate novel pathogenic mechanisms of calcium stone formation in specific subsets of patients.

Urolithiasis, Independent of Uric Acid, Increased Risk of Coronary Artery and Carotid Atherosclerosis: A Meta-Analysis of Observational Studies

Background and Aims

Recent epidemiological evidence indicates an association between urolithiasis and atherosclerosis; however, results are incongruous. Our aim is to summarize the association between urolithiasis and arteriosclerosis risk through a detailed meta-analysis.

Methods

Relevant studies published before April 2019 were identified by searching OVID, EMBASE, PubMed, Web of Science database, and Cochrane Library. The relationship between urolithiasis and the risk of atherosclerosis was assessed by using odds ratio (OR) values and the corresponding 95% confidence intervals (CIs), and the selection of fixed- or random-effects model based on heterogeneity.

Results

The meta-analysis includes 8 observational studies that contained 70,716 samples. Pooled results showed that urolithiasis was associated with an increased adjusted and unadjusted risk estimated for atherosclerosis (P=0.017 and P=0.017 and n = 65,751/70,716) with serum uric acid levels less than 6.0 mg/dl, it still showed that urolithiasis was associated with a higher risk of atherosclerosis (P=0.017 and I² = 0.0%, P=0.017 and P=0.017 and P=0.017 and

Conclusions

Urolithiasis is associated with an increased risk for atherosclerosis, especially in coronary artery and carotid atherosclerosis. Urolithiasis may be another potential risk factor of atherosclerosis, which is independent of serum uric acid levels.

Immunotherapy for stone disease

PURPOSE OF REVIEW

In addition to traditional risk factors such as low urine volume or hypercalciuria, emerging data suggest that calcium oxalate (CaOx), one of the most common mineral complexes in the urine, elicits a strong immunologic response. This review highlights those studies and projects how future therapies may be directed for kidney stone prevention.

RECENT FINDINGS

Over the last 2 years, several groups have studied the response of the immune system to CaOx crystals using cell culture and animal models. Dominguez et al. found that CaOx crystals were recognized by monocytes through an lipopolysaccharide-mediated mechanism, leading to M1 'inflammatory' macrophage phenotype. Patel et al. proposed excessive oxalate-mediated reactive oxygen species within macrophage mitochondria may impair their ability to properly clear stones. Two other groups developed mouse models (an androgen receptor knock-out and an overexpression of Sirtuin 3 protein) and demonstrated increased renal anti-inflammatory macrophage differentiation and decreased CaOx deposition in experimental compared with controls. Anders et al. fed hyperoxaluric mice 1,3-butanediol, which blocks an inflammatory form of cell death called NLRP3 inflammasome and found less intrarenal oxidative damage and higher anti-inflammatory renal infiltrates in experimentals. Finally, monocytes exposed to CaOx crystals followed by hydroxyapatite had reduced inflammatory cytokine and chemokine production compared with those without hydroxyapatite, suggesting that Randall's plaque may play a role in dampening M1-mediatiated CaOx inflammation.

SUMMARY

By modulating the immune response, immunotherapy could provide the means to prevent stone recurrences in certain individuals. The promotion of M2 over M1 macrophages and inhibition of inflammation could prevent the cascade that leads to CaOx nucleation. Future therapies may target the ability of macrophages to degrade CaOx crystals to prevent stones.

Lipidomics Reveals the Therapeutic Effects of EtOAc Extract of Orthosiphon stamineus Benth. on Nephrolithiasis

Background

Nephrolithiasis is a systemic metabolic disease with a high prevalence worldwide and is closely related to lipid-mediated oxidative stress and inflammation. Orthosiphon stamineus Benth. (OS) is a traditional medicinal herb mainly containing flavonoids, caffeic acid derivatives, and terpenoids, which has the effect of treating urinary stones. However, the active ingredients of OS for the treatment of kidney stones and their regulatory mechanisms remain unknown. As a powerful antioxidant, flavonoids from herbs can mitigate calcium oxalate stone formation by scavenging radical. Thus, this work focused on EtOAc extract of OS (EEOS, mainly flavonoids) and aimed to reveal the potential intrinsic mechanism of EEOS in the treatment of kidney stones disease.

Methods

Firstly, 75% ethanol extract of OS was further extracted with EtOAc to obtain EtOAc extract containing 88.82% flavonoids. Secondly, the extract was subjected to component analysis and used in animal experiments. Then, an untargeted lipidomics based on ultrahigh performance liquid chromatography coupled with TripleTOF 5600 mass spectrometer (UPLC-QTOF-MS) was performed to test the lipid changes of kidneys in the control group, model group and EEOS treatment groups. Finally, multivariate statistical analysis was used to identify differences between the lipid profiles of mice in the model group and the EEOS group.

Results

Fifty-one lipid metabolites were significantly different between the mice in the model group and the EEOS intervention group, including glycerophosphocholines, glycerophosphoethanolamines, glycerophosphoinositols, and glycerophosphoglycerols. And the composition of glycerophospholipids-esterified ω-3 polyunsaturated fatty acids and glycerophospholipid subclasses in the kidneys of the EEOS group significantly changed compared to model group.

Conclusions

The EEOS can inhibit the stones formation by improving oxidative stress and inflammation mediated by glycerophospholipid metabolism. This study reveals the potential mechanism of EEOS for kidney stones treatment at the lipid molecule level, providing a new direction for further study of the efficacy of OS.

Oxalate Content and Antioxidant Activity of Different Ethnic Foods

OBJECTIVE

There is not enough information on the classification of oxalate content in several foods, particularly in ethnic foods, to recommend their consumption in subjects with urolithiasis (UL). The objective of the present study was to generate reliable information on the oxalate content and antioxidant activity in different foods and classify them by very low, low, medium, high and very high oxalate content and antioxidant activity.

METHODS

The oxalate content of 109 foods including ethnic foods was assessed by an enzymatic assay, and the antioxidant activity was measured by the oxygen radical absorbance capacity to determine the oxalate/antioxidant activity ratio. Oxalate consumption was then evaluated in 400 subjects with overweight and obesity using 24-h dietary recalls.

RESULTS

The main foods with high oxalate content were raw spinach, huanzontle, purslane, chard, almond, and toasted and sweetened roasted amaranth. The highest antioxidant activity was found in strawberries, all types of chocolates, roselle, morita peppers, and pinolillo. Subjects with overweight or obesity exceed the dietary oxalate daily intake recommendation.

CONCLUSIONS

The classification of foods by their oxalate content and antioxidant activity will be very useful to generate nutritional recommendation in different diseases, mainly UL.

Repair of Tea Polysaccharide Promotes the Endocytosis of Nanocalcium Oxalate Monohydrate by Damaged HK-2 Cells

Endocytosis is a protective mechanism of renal epithelial cells to eliminate retained crystals. This research investigated the endocytosis of 100 nm calcium oxalate monohydrate crystals in human kidney proximal tubular epithelial (HK-2) cells before and after repair by four kinds of tea polysaccharides with molecular weights (MWs) of 10.88 (TPS0), 8.16 (TPS1), 4.82 (TPS2), and 2.31 kDa (TPS3), respectively. When HK-2 cells were repaired by TPSs after oxalic acid injury, the cell viability, wound healing ability, mitochondrial membrane potential, percentage of cells with endocytosed crystals, and dissolution rate of the endocytosed crystals increased; the cell morphology recovered; and the reactive oxygen level and lactate dehydrogenase release decreased. Most of the endocytosed crystals were found in the lysosomes. The repair effects of the four TPSs were ranked in the following order: TPS2>TPS1>TPS3>TPS0. TPS2 with moderate MW presented the optimal repair ability and strongest ability to promote endocytosis.

Two-Dimensional Immiscible Domain of Cholesterol in the Lipid Bilayer Membrane Promotes Early Stage Calcification by Inducing Oriented Nucleation of Hydroxyapatite

Biomineralization is characterized by the fact that the crystallization of inorganic minerals is guided by an in vivo biological interface. However, the interfaces that direct calcification are widely debated up to date. In this paper, it was found that the two-dimensional (2D) immiscible domain of cholesterol in the lipid bilayer can induce the deposition of calcium phosphate by rapidly promoting the nucleation of the hydroxyapatite (001) plane. This promotion effect is related to the high lattice matching degree between the 2D cholesterol immiscible domain and the (001) plane of hydroxyapatite (HAP), which leads to the heteroepitaxy of HAP. The lipid bilayer derived from cells or vesicles is the largest biological interface in the body, thus revealing whether the lipid bilayer can induce the deposition of calcium phosphate will facilitate the understanding of the important role of cells or vesicles in calcification.

A Short Review on the Relationships Between Nephrolithiasis and Myocardial Infarction

The interaction between organs is a crucial part of modern medicine. As a very prerequisite to manage a disease, practitioners should have a full awareness of the related organs. Kidney and heart are two vital organs that are closely interconnected in various fields. These two organs have a lot of common risk factors for making a person unhealthy; therefore, if you prevent the disease in one of them, the other's morbidity might be alleviated as well. Among them, nephrolithiasis and myocardial infarction (MI) have more risk factors in common, and both could be fatal. Also, these two diseases are important regarding the prevalence, incidence, and burden of disease. Some studies confirm the relationship between MI and nephrolithiasis; however, further researches are needed to discover the exact direction of their relationship. The present review aims to explain the mechanism of MI and nephrolithiasis; clarify the relationship between these two disease based on physiological, pathological, and clinical studies; and propose some solutions for the prevention and treatment of such diseases.

Which Diet for Calcium Stone Patients: A Real-World Approach to Preventive Care

Kidney stone disease should be viewed as a systemic disorder, associated with or predictive of hypertension, insulin resistance, chronic kidney disease and cardiovascular damage. Dietary and lifestyle changes represent an important strategy for the prevention of kidney stone recurrences and cardiovascular damage. A full screening of risk factors for kidney stones and for cardiovascular damage should be recommended in all cases of calcium kidney stone disease, yet it is rarely performed outside of stone specialist clinics. Many patients have a history of kidney stone disease while lacking a satisfactory metabolic profile. Nonetheless, in a real-world clinical practice a rational management of kidney stone patients is still possible. Different scenarios, with different types of dietary approaches based on diagnosis accuracy level can be envisaged. The aim of this review is to give patient-tailored dietary suggestions whatever the level of clinical and biochemistry evaluation. This can help to deliver a useful recommendation, while avoiding excessive dietary restrictions especially when they are not based on a specific diagnosis, and therefore potentially useless or even harmful. We focused our attention on calcium stones and the different scenarios we may find in the daily clinical practice, including the case of patients who reported renal colic episodes and/or passed stones with no information on stone composition, urinary risk factors or metabolic cardiovascular risk factors; or the case of patients with partial and incomplete information; or the case of patients with full information on stone composition, urinary risk factors and metabolic cardiovascular profile.

The lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy

AIM

To evaluate the level of lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy (ESWL).

MATERIALS & METHODS

Isoprostane concentration (8-isoPGF_2α) was measured in urine, and thiobarbituric acid reactive substance production in serum and erythrocytes. In addition, the concentrations of selected compounds (uric acid, glucose and creatinine) were measured in serum.

RESULTS

The patients (before and after ESWL) demonstrated significantly higher levels of two different biomarkers of lipid peroxidation compared with the control group. A correlation was identified between increased amounts of uric acid and biomarkers of lipid peroxidation in patients with nephrolithiasis, both before and after ESWL.

CONCLUSION

Uric acid may be associated with lipid peroxidation in patients with nephrolithiasis.

Anatomic variations and stone formation

PURPOSE OF REVIEW

The pathophysiological mechanisms in kidney stone formation are insufficiently understood. In order to achieve a better understanding of the complexity of stone formation, studies evaluating anatomical variations in the renal papillae have been performed. This review intends to illuminate recent findings. Moreover, new techniques to improve the understanding and interpretation of crystallization mechanisms are reviewed.

RECENT FINDINGS

Due to improvements of digital ureteroscopes, detailed endoscopic mapping of renal papillae is now possible. Connections between papillary morphology and histopathological changes in different subsets of stone formers have been documented. The formation of kidney stones seems to take place in relation to Randall's plaques, Ducts of Bellini or by free formation. Additionally, theories of kidney stone formation because of vascular injury or inflammatory events in the papillae have been suggested.

SUMMARY

Novel techniques including improved digital endoscopic visualization, microcomputed tomography (CT), electron microscopy and energy dispersive compositional analyses of kidney stones seem essential in the search for effective and reliable methods to understand stone forming processes, which ultimately should result in effective measures for more personalized stone prevention strategies in the future.