Protective Cellular Mechanism of Estrogen Against Kidney Stone Formation: A Proteomics Approach and Functional Validation

Univariable and multivariable mendelian randomization study revealed the modifiable risk factors of urolithiasis

BACKGROUND

Urolithiasis is a common urological disease with increasing incidence worldwide, and preventing its risk poses significant challenges. Here, we used Mendelian randomization (MR) framework to genetically assess the causal nature of multifaceted risk factors on urolithiasis.

METHODS

17 potential risk factors associated with urolithiasis were collected from recently published observational studies, which can be categorized basically into lifestyle factors and circulating biomarkers. The instrumental variables of risk factors were selected from large-scale genome-wide association studies (N ≤ 607,291). Summary-level data on urolithiasis were obtained from UK Biobank (UKB) (3,625 cases and 459,308 noncases) and the FinnGen consortium (5,347 cases and 213,445 noncases). The univariable and multivariable MR analyses were applied to evaluate the causal, independent effect of these potential risk factors upon urolithiasis. Effects from the two consortia were combined by the meta-analysis methods.

RESULTS

Higher genetically predicted sex hormone-binding globulin (SHBG, OR, 0.708; 95% CI, 0.555 to 0.903), estradiol (OR, 0.179; 95% CI, 0.042 to 0.751), tea intake (OR, 0.550; 95% CI, 0.345 to 0.878), alcoholic drinks per week (OR, 0.992; 95% CI, 0.987 to 0.997), and some physical activity (e.g., swimming, cycling, keeping fit, and bowling, OR, 0.054; 95% CI, 0.008 to 0.363) were significantly associated with a lower risk of urolithiasis. In the Multivariate Mendelian Randomization (MVMR) analyses, the significant causal associations between estradiol, SHBG, tea intake, and alcoholic drinks per week with urolithiasis were robust even after adjusting for potential confounding variables. However, the previously observed causal association between other exercises and urolithiasis was no longer significant after adjusting for these factors.

CONCLUSIONS

The univariable and multivariable MR findings highlight the independent and significant roles of estradiol, SHBG, tea intake, and alcoholic drinks per week in the development of urolithiasis, which might provide a deeper insight into urolithiasis risk factors and supply potential preventative strategies.

Association between hysterectomy and kidney stone disease: results from the National Health and Nutrition Examination Survey 2007-2018 and Mendelian randomization analysis

PURPOSE

Hysterectomy is one of the most common types of gynecological operations and it is associated with numerous postoperative complications. Few studies have reported a definitive association between hysterectomy and kidney stone disease (KSD). This study aimed to explore whether hysterectomy increases the risk of KSD.

METHODS

This is a cross-sectional study that used six continuous cycles of data obtained from the National Health and Nutrition Examination Survey from 2007 to 2018. The correlations between hysterectomy or age at hysterectomy and the prevalence of KSD were assessed using weighted multivariable-adjusted logistic regression. Further, five methods of two-sample Mendelian randomization (MR) were applied to decrease bias and infer causality in the observational study.

RESULTS

After adjusting for potential confounders, hysterectomy (OR: 1.37, 95% CI 1.04-1.81) was found to be positively associated with the prevalence of KSD, whereas age at hysterectomy was found to be negatively associated with the prevalence of KSD (OR: 0.96, 95% CI: 0.94-0.98). In the inverse-variance weighted method, MR analyses suggested that genetically predicted hysterectomy is causally associated with a higher risk of KSD (OR: 11.961, 95% CI 1.12-1.28E2).

CONCLUSIONS

Hysterectomy could increase the risk of KSD. Younger age at hysterectomy is associated with a higher risk of KSD. Further prospective cohort studies with larger sample sizes and longer follow-up times are needed.

Characterizations of annexin A1-interacting proteins in apical membrane and cytosolic compartments of renal tubular epithelial cells

Annexin A1 (ANXA1) is a multifunctional calcium-binding protein that can bind to membrane phospholipids. Under high-calcium condition, ANXA1 expression increases on renal epithelial cell surface, leading to enhanced adhesion of calcium oxalate (CaOx) crystal (stone material) onto the cells. To regulate various cellular processes, ANXA1 interacts with many other intracellular protein partners. However, components of the ANXA1-interacting protein complex remain unclear. Herein, we characterized the interacting complexes of apical membrane (ApANXA1) and cytosolic (cyANXA1) forms of ANXA1 in apical membrane and cytosolic compartments, respectively, of renal epithelial cells under high-calcium condition using proteomic and bioinformatic approaches. After fractionation, the ApANXA1- and CyANXA1-interacting partners were identified by immunoprecipitation followed by nanoLC‑ESI‑Qq-TOF tandem mass spectrometry (IP-MS/MS). The ANXA1-interacting partners that were common in both apical membrane and cytosolic compartments and those unique in each compartment were then analyzed for their physico-chemical properties (molecular weight, isoelectric point, amino acid contents, instability index, aliphatic index, and grand average of hydropathicity), secondary structure (α-helix, β-turn, random coil, and extended strand), molecular functions, biological processes, reactome pathways and KEGG pathways. The data demonstrated that each set of these interacting proteins exhibited common and unique characteristics and properties. The knowledge from this study may lead to better understanding of the ApANXA1 and CyAXNA1 biochemistry and functions as well as the pathophysiology of CaOx kidney stone formation induced by high-calcium condition.

Metabolic changes in kidney stone disease

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

National analysis of urinary cadmium concentration and kidney stone: Evidence from NHANES (2011–2020)

Background

The association between urinary cadmium and kidney stone risk is inconsistent in previous studies, which needs further exploration. This study was performed to explore the association between urinary cadmium and kidney stone.

Materials and methods

Data from the National Health and Nutrition Examination Survey (2011–2020) were included and further analyzed. Urinary cadmium was stratified into quartiles with quartile 1 (Q1: 0.025–0.104 μg/L) and quartile 4 (Q4: 0.435–7.581 μg/L). Further weighted logistic regression was adopted to evaluate the association between urinary cadmium and kidney stone. A subgroup analysis was used to verify the findings. The non-linear association was examined using the restricted cubic spline (RCS) regression.

Results

A total of 9,056 adults aged 20 years and above were included in this study. In the fully adjusted model, an increased risk of kidney stones was identified for quartile 2 (OR = 1.40, 95% CI = 1.06–1.84, P < 0.05), quartile 3 (OR = 1.18, 95% CI = 0.88–1.59, P > 0.05), and quartile 4 (OR = 1.54, 95% CI = 1.10–2.06, P < 0.05). A similar association was found between continuous cadmium increase and OR of kidney stones in the fully adjusted model (OR = 1.13, 95% CI = 1.01–1.26, P < 0.05). The RCS also indicated a non-linear association between urinary cadmium concentration and kidney stone risk (P for non-linear < 0.001).

Conclusion

In summary, cadmium exposure is identified as a risk factor for kidney stones in this study. Their non-linear association makes demands on early intervention for the cadmium-exposed population. Medical interventions for kidney stone prevention should take cadmium exposure into account.

Risk factors for upper urinary tract uroliths and ureteral obstruction in cats under referral veterinary care in the United Kingdom

BACKGROUND

Cats presenting with upper urinary tract uroliths (UUTUs) and ureteral obstruction ("obstructive UUTU") are typically younger than cats with idiopathic CKD that often have incidental nephroliths.

HYPOTHESIS

Cats with upper urinary tract urolith have 2 clinical phenotypes; a more aggressive phenotype at risk of obstructive UUTU at a young age and a more benign phenotype in older cats, with reduced risk of obstructive UUTU.

OBJECTIVES

Identify risk factors for UUTU and for obstructive UUTU.

ANIMALS

Eleven thousand four hundred thirty-one cats were referred for care over 10 years; 521 (4.6%) with UUTU.

METHODS

Retrospective VetCompass observational cross-sectional study. Multivariable logistic regression models were performed to identify risk factors for a diagnosis of UUTU vs no UUTU and additionally, obstructive UUTU vs nonobstructive UUTU.

RESULTS

Risk factors for UUTU included female sex (odds ratio [OR] 1.6, confidence interval [CI] 1.3-1.9; P < .001), British shorthair, Burmese, Persian, Ragdoll or Tonkinese (vs non-purebred ORs 1.92-3.31; P < .001) breed and being ≥4 years (ORs 2.1-3.9; P < .001). Risk factors for obstructive UUTU were female sex (OR 1.8, CI 1.2-2.6; P = .002), having bilateral uroliths (OR 2.0, CI 1.4-2.9; P = .002) and age, with the odds of obstructive UUTU increasing as age at diagnosis of UUTU decreased (≥12 years, reference category; 8-11.9 years, OR 2.7, CI 1.6-4.5; 4-7.9 years, OR 4.1, CI 2.5-7.0; 0-3.9 years, OR 4.3, CI 2.2-8.6; P < 0.001).

CONCLUSIONS AND CLINICAL IMPORTANCE

Cats diagnosed with UUTU at a younger age have a more aggressive phenotype with higher risk of obstructive UUTU compared to cats over 12 years of age diagnosed with UUTU.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

DISCUSSION

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

Sex disparities and the risk of urolithiasis: a large cross-sectional study

BACKGROUND

Urolithiasis is one of the most common diseases in urology, with a lifetime prevalence of 14% and is more prevalent in males compared to females. We designed to explore sex disparities in the Chinese population to provide evidence for prevention measures and mechanisms of stone formation.

MATERIALS AND METHODS

A total of 98232 Chinese individuals who had undergone a comprehensive examination in 2017 were included. Fully adjusted odds ratios for kidney stones were measured using restricted cubic splines. Multiple imputations was applied for missing values. Propensity score matching was utilised for sensitivity analysis.

RESULTS

Among the 98232 included participants, 42762 participants (43.53%) were females and 55470 participants (56.47%) were males. Patients' factors might cast an influence on the development of kidney stone disease distinctly between the two genders. A risk factor for one gender might have no effect on the other gender. The risk for urolithiasis in females continuously rises as ageing, while for males the risk presents a trend to ascend until the age of around 53 and then descend.

CONCLUSIONS

Patients' factors might influence the development of kidney stones distinctly between the two genders. As age grew, the risk to develop kidney stones in females continuously ascended, while the risk in males presented a trend to ascend and then descend, which was presumably related to the weakening of the androgen signals.Key messagesWe found that patients' factors might cast an influence on the development of kidney stone disease distinctly between the two sexes.The association between age and urolithiasis presents distinct trends in the two sexesThe results will provide evidence to explore the mechanisms underlying such differences can cast light on potential therapeutic targets and promote the development of tailored therapy strategies in prospect.

Contamination of bacterial extracellular vesicles (bEVs) in human urinary extracellular vesicles (uEVs) samples and their effects on uEVs study

Bacterial overgrowth is common for improperly stored urine. However, its effects on human urinary extracellular vesicles (uEVs) study had not been previously examined nor documented. This study investigated the presence of bacterial EVs (bEVs) contaminated in uEVs samples and their effects on uEVs study. Nanoscale uEVs were isolated from normal human urine immediately after collection (0-h) or after 25°C-storage with/without preservative (10 mM NaN3) for up to 24-h. Turbidity, bacterial count and total uEVs proteins abnormally increased in the 8-h and 24-h-stored urine without NaN3. NanoLC-ESI-LTQ-Orbitrap MS/MS identified 6-13 bacterial proteins in these contaminated uEVs samples. PCR also detected bacterial DNAs in these contaminated uEVs samples. Besides, uEVs derived from 8-h and 24-h urine without NaN3 induced macrophage activation (CD11b and phagocytosis) and secretion of cytokines (IFN-α, IL-8, and TGF-β) from macrophages and renal cells (HEK-293, HK-2, and MDCK). All of these effects induced by bacterial contamination were partially/completely prevented by NaN3. Interestingly, macrophage activation and cytokine secretion were also induced by bEVs purified from Escherichia coli. This study clearly shows evidence of bEVs contamination and their effects on human uEVs study when the urine samples were inappropriately stored, whereas NaN3 can partially/completely prevent such effects from the contaminated bEVs.

Global, Regional, and National Burden of Urolithiasis from 1990 to 2019: A Systematic Analysis for the Global Burden of Disease Study 2019

Introduction

To get insight into the temporal trends of urolithiasis, and thus decrease the health burden of urolithiasis, we comprehensively investigated the specific epidemiological indicators that varied among different countries and regions according to the diversity of geographic locations, gender, age, year, and socioeconomic status.

Methods

In this study, we investigated the incidence, death, disability-adjusted life years (DALYs) of urolithiasis quantified by the number of patients, age-standardized rates, and estimated annual percentage changes based on geographic locations, gender, age, and year to decode the epidemiological characteristics using the data from 1990 to 2019 in the Global Burden of Disease database.

Results

In 2019, more than 115 million (95% uncertainty interval [95% UI] 93–140) incident cases of urolithiasis occurred worldwide, and the age-standardized incidence rate (ASIR) (per 100,000 population) decreased from 1696.2 (1358.1–2078.1) in 1990 to 1394 (1126.4–1688.2) in 2019. Nearly 13,279 (95% UI: 10616–16267) died of urolithiasis, contributing to 0.6 million (0.5–0.7) DALYs in 2019. The highest age-standardized DALY rates (33.33 per 100 000 population) in 2019 were observed in Armenia, whereas the largest negative estimated annual percentage changes of DALYs were seen in Poland. The ASIR of males was higher than females. However, the ASIR EAPC of males was lower than females from 1990 to 2019. Males aged 50–54 years old were more likely to suffer from urolithiasis. Joinpoint regression model analyses suggested that the global age-standardized incidence and DALY rates of urolithiasis encountered a trend to decline over the past 30 years. Over the years, the attenuation of this disease was pinpointed to be weakly related to the Socio-demographic index.

Conclusion

At the global level, both the incident and DALY cases experienced substantial growth compared to the absolute cases in 1990. However, global age-standardized incidence and DALY rate of urolithiasis were observed to decline from 1990 to 2019. Males’ ASIR was higher than females, while the gap narrowed over the years. A weakly positive correlation between ASIR of urolithiasis and SDI was also observed in this study.

Maternal lead exposure induces sex-dependent cerebellar glial alterations and repetitive behaviors

Lead (Pb) is one of the most prevalent heavy metals we encounter daily. Although there are many reports regarding their toxic effects on humans, the effects of exposure to low lead concentrations throughout the pregnancy period on the offspring are not fully elucidated yet. This study aimed to investigate the cellular mechanisms that occur in response to lead exposure. To this end, we administered lead-containing water to pregnant mice from the day of conception till delivery or till day 28 postnatally. Furthermore, we performed neurodevelopmental disorder-related behavior tests and RNA-sequencing analysis. We used both genders for all experiments because neurodevelopmental disorders usually show several sex-dependent differences. The results revealed increased levels of gliosis in the cerebella of lead-exposed pups compared to those in littermates belonging to the control group. Additionally, we observed altered behaviors of male mice in the autism spectrum disorder-related tests. RNA-sequencing results revealed changes in gamma-aminobutyric acid (GABA) signaling in the lead-exposed mouse model. Specifically, the lead-exposed male mice showed decreased monoamine oxidase B and increased levels of diamine oxidase enzyme, which is related to the synthesis of GABA in astrocytes. These findings demonstrate sex-dependent basal developmental changes in glial cells and an increased prevalence of autistic-like behaviors in the young pups of mothers exposed to lead during pregnancy.

Persistent Escherichia coli infection in renal tubular cells enhances calcium oxalate crystal-cell adhesion by inducing ezrin translocation to apical membranes via Rho/ROCK pathway

Recent evidence has suggested that recurrent urinary tract infection (UTI) can cause not only infection stones but also metabolic stones (e.g., those containing calcium oxalate monohydrate or COM). However, precise mechanisms underlying UTI-induced metabolic stones remained unknown. In this study, Escherichia coli, the most common bacterium found in recurrent UTI was used to establish the in vitro model for persistent infection of renal epithelial cells. The promoting effects of persistent E. coli infection on kidney stone formation were validated by COM crystal-cell adhesion assay, followed by immunofluorescence study for changes in surface expression of the known COM crystal receptors. Among the five receptors examined, only ezrin had significantly increased level on the surface of persistently infected cells without change in its total level. Such translocation of ezrin to apical membranes was confirmed by Western blotting of apical membrane and cytosolic fractions and confocal microscopic examination. Additionally, persistent infection increased phosphorylation (Thr567) of ezrin. However, all of these changes induced by persistent E. coli infection were significantly inhibited by small-interfering RNA (siRNA) specific for ezrin or a Rho-associated kinase (ROCK)-specific inhibitor (Y-27632). In summary, this study provides a piece of evidence demonstrating that persistent infection by E. coli, one of the non-urease-producing bacteria, may contribute to COM metabolic stone formation by translocation of ezrin to apical membranes, thereby promoting COM crystal-cell adhesion. Such ezrin translocation was mediated via Rho/ROCK signaling pathway. These findings may, at least in part, explain the pathogenic mechanisms underlying recurrent UTI-induced metabolic kidney stone disease.

Analysis of Threshold Effect of Urinary Heavy Metal Elements on the High Prevalence of Nephrolithiasis in Men

Exposure to heavy metals in the environment exerts serious effects on kidney health. However, the effects of joint exposure on the kidneys have been rarely studied, particularly in non-occupational exposure high-risk populations. This study provided a reference threshold range of heavy metals in urine and explored the effect of joint exposure on nephrolithiasis in men. The data were obtained from the China Multi-Ethnic Cohort database, and 1502 men were included in the study. A two-piece-wise regression model was used to assess the dose-response relationship between heavy metal exposure and nephrolithiasis. The least absolute shrinkage and selection operator regression model was used to calculate the score of joint exposure to heavy metals. The threshold effect analysis revealed a linear relationship between the concentration of arsenic (As) in the urine and the prevalence of nephrolithiasis, whereas a nonlinear relationship was observed with cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb). In addition, As, Cd, Cr, Hg, and Pb may significantly affect the joint exposure effect. Moreover, the final risk of nephrolithiasis increased by 123% (P for trend < 0.001). This study found a threshold relationship between heavy metals (Cd, Cr, Hg, Pb) in male urine and the occurrence of nephrolithiasis. Joint exposure to heavy metals in urine caused a high-risk effect on nephrolithiasis. The study provided a reference threshold value of related studies and indicated that environmental pollution caused by heavy metals should be reduced.

Sex Disparities in the Association of Serum Uric Acid With Kidney Stone: A Cross-Sectional Study in China

Background and Aims

Urolithiasis is characterized by high rates of prevalence and recurrence. Hyperuricemia is related to various diseases. We hope to determine the association between serum uric acid (UA) level and kidney stone (KS).

Methods

In this population-based cross-sectional study, a total of 82,017 Chinese individuals who underwent a comprehensive examination in 2017 were included. The KS was diagnosed based on ultrasonography examination outcomes. Fully adjusted odds ratio (OR) for KS, and mean difference between the two groups were applied to determine the association of UA level with KS.

Results

Among the 82,017 participants included in this study (aged 18~99 years), 9,435 participants (11.5%) are diagnosed with KS. A proportion of 56.3% of individuals is male. The mean UA level of overall participants is 341.77 μmol/L. The participants with KS report higher UA level than the participants without KS [mean UA level 369.91 vs. 338.11 μmol/L; mean difference (MD), 31.96 (95% CI, 29.61~34.28) μmol/L]. In men, the OR for KS significantly increases from 330 μmol/L UA level. Every 50 μmol/L elevation of UA level increases the risk of KS formation by about 10.7% above the UA level of 330 μmol/L in men. The subgroup analysis for male is consistent with the overall result except for the participants presenting underweight [adjusted OR, 1.035 (0.875~1.217); MD, −5.57 (−16.45~11.37)], low cholesterol [adjusted OR, 1.088 (0.938~1.261); MD, 8.18 (−7.93~24.68)] or high estimated glomerular filtration rate (eGFR) [adjusted OR, 1.044 (0.983~1.108); MD, 5.61 (−1.84~13.36)]. However, no significant association is observed in women between UA and KS either in all female participants or in female subgroups.

Conclusion

Among Chinese adults, UA level is associated with KS in a dose-response manner in men but not in women. However, the association becomes considerably weak in male participants with malnutrition status.

Relationship Between Serum Testosterone Levels and Kidney Stones Prevalence in Men

BACKGROUND

The role of serum testosterone levels in male renal stone formation remains controversial. This study aimed to evaluate the relationship between serum testosterone levels and kidney stone prevalence in males.

METHODS

We conducted a cross-sectional study based on the data from the National Health and Nutrition Examination Survey 2011-2016, which included 6,633 male participants, to investigate the association between testosterone levels and the prevalence of kidney stones.

RESULTS

In this study, using the highest quartile of serum testosterone as a reference, a logistic regression model adjusted for confounders in all participants showed that the first quartile (OR: 1.375, p = 0.016), the second quartile (OR: 1.348, p = 0.021), and the third quartile (OR: 1.472, p = 0.003) of testosterone significantly increased kidney stone risks. In the 41-60 age group, the ORs of kidney stone risk in the first, second, and third of serum testosterone were 1.904 (P = 0.005), 1.599 (P = 0.040), and 1.734 (P = 0.015), respectively. This trend can also be found in the 61-80-year group, except in the first quartile of serum testosterone (OR: 1.169, P = 0.436). Adjusted smoothed curves suggest a non-linear relationship between the 8 quantiles of serum testosterone and the risk of kidney stones in all participants and the 61-80 age group and a significant negative relationship in the 41-60 age group (OR: 0.921, P = 0.0193). But no correlation was seen in the 20-40 group.

CONCLUSIONS

Serum testosterone levels were significantly inversely associated with the prevalence of kidney stones in men over 40 years of age, but no correlation was seen in the 20-40 group. The role of testosterone in stone formation should be redefined, and its effect should be further verified.

Therapeutic Potential of Annexin A1 Modulation in Kidney and Cardiovascular Disorders

Renal and cardiovascular disorders are very prevalent and associated with significant morbidity and mortality. Among diverse pathogenic mechanisms, the dysregulation of immune and inflammatory responses plays an essential role in such disorders. Consequently, the discovery of Annexin A1, as a glucocorticoid-inducible anti-inflammatory protein, has fueled investigation of its role in renal and cardiovascular pathologies. Indeed, with respect to the kidney, its role has been examined in diverse renal pathologies, including acute kidney injury, diabetic nephropathy, immune-mediated nephropathy, drug-induced kidney injury, kidney stone formation, and renal cancer. Regarding the cardiovascular system, major areas of investigation include the role of Annexin A1 in vascular abnormalities, atherosclerosis, and myocardial infarction. Thus, this review briefly describes major structural and functional features of Annexin A1 followed by a review of its role in pathologies of the kidney and the cardiovascular system, as well as the therapeutic potential of its modulation for such disorders.

Gender Differences in Kidney Stone Disease (KSD): Findings from a Systematic Review

PURPOSE OF REVIEW

The prevalence of kidney stones is rising and historically carries a preponderance for males. However, recent evidence has questioned whether this gender gap is closing. The aim of this systematic review was to examine this further as well as evaluate possible underlying causes.

RECENT FINDINGS

Recent evidence confirms the disparity in kidney stone disease between genders is closing. In the modern era, the rise in prevalence among females has been greater, especially in adolescence. Quality of life is also more adversely affected by kidney stone events among females who are also more likely to develop sepsis after endourological surgery. Males, however, are more likely to present with stone events during periods of high ambient temperatures Recent literature demonstrates a temporal change in the disease burden of KSD among men and women. The latter, especially adolescent females, are more likely to develop KSD in their lifetime compared to previous eras. Determining causation is complex and continued research is warranted.

Kidney stone proteomics: an update and perspectives

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Calculus-related functional protein expression in ureteral calculus-adhered polyp: A preliminary study

To explore the expressions of calculus-related functional proteins in the ureteral calculus-adhered polyp tissues and investigate the role of these proteins in the formation of adhesions between the calculus and polyp.Patients with ureteral calculi and polyps who underwent ureteroscopic lithotripsy for the excision of polyps between January 2019 and June 2019 were enrolled. Polyps obtained from each patient were divided into 2 groups using a matched pairs design: observation group (polyps adhered to calculus) and control group (polyps not adhered to calculus). Histopathological examination of polyps was performed using hematoxylin and eosin staining. Polyp tissues were immunohistochemically stained to assess the expressions of calculus-related functional proteins, that is, annexin A1, calcium-binding protein S100A9 (S100A9), uromodulin, and osteopontin. Furthermore, quantitative analysis was performed using the H-score of tissue staining; Pearson correlation analysis was performed for proteins with high expression.Overall, 40 polyp specimens were collected from 20 patients with ureteral calculi combined with polyps (observation group, 20 specimens; control group, 20 specimens). Hematoxylin and eosin staining revealed obvious epithelial cell proliferation in polyps of both groups; crystals were observed in the epithelial cells of the polyp tissue in the observation group. The expression levels of annexin A1 and S100A9 in the observation group were significantly greater than those in the control group (P < .05). However, no obvious expression of osteopontin or uromodulin was observed in the polyp tissues of both groups. There was a strong correlation between the increased expressions of annexin A1 and S100A9 in the observation group (R = 0.741, P = .022).We documented increased expressions of annexin A1 and S100A9 in the ureteral calculus-adhered polyp tissues. Annexin A1 and S100A9 may play an essential role in the adhesion of calculus and polyp and the growth of calculi.

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.

A single day fasting may increase emergency room visits due to renal colic

We aimed to explore whether a single-day of fasting (SDF) increase emergency room (ER) visits due to renal colic (RC). We elected to concentrate on Yom-Kippur (i.e.: SDF), the holiest day in Judaism. Food and liquid consumption is prohibited during this day for 25 h, and an estimated 50–70% fasting rate is observed. SDF always takes place between mid-September and mid-October during which the temperature in the Middle-East ranges between 19 and 30 °C. ER visits for RC between 01/2012 and 11/2019 were reviewed, and the Gregorian days on which SDF occurred were retrieved. The number of ER visits for RC was compared between SDF and the surrounding days/months as well as to another single-day "standard" holiday (SDSH) that precedes SDF in 10 days and is not associated with fasting. Of 11,717 ER visits for RC, 8775 (74.9%) were males. Male:Female ratio was 3:1. The mean daily number of ER visits for RC during the 3 days following SDF was 6.66 ± 2.49, significantly higher compared with the mean annual daily visits (4.1 ± 2.27, p < 0.001), the mean daily visits during the week prior to SDF (5.27 ± 2.656, p = 0.032), and the mean daily visits during September (5.06 ± 2.659, p = 0.005), and October (4.78 ± 2.23, p < 0.001). The mean number of ER daily visits for RC during the 3 days following SDSH, 5.79 ± 2.84, did not differ compared with the mean daily visits during September and October (p = 0.207; p = 0.13, respectively). It was lower compared to SDF, however statistically insignificant (p = 0.285). A single-day fasting may increase ER visits for RC. The mechanism underlying this phenomenon is unknown.

Metabolomics analysis of the serum from children with urolithiasis using UPLC-MS

Pediatric urolithiasis is a common urologic disease with high morbidity and recurrence rates. Recent studies have shown that metabolic dysfunction plays a vital role in the pathogenesis of urolithiasis, especially in children, but the specific mechanism is still unclear. Metabolomics is an ideal technology for exploring the mechanism of metabolic disorders in urolithiasis. In the present study, a serum metabolomics based on ultra‐performance liquid chromatography mass spectrometry was performed. A total of 50 children subjects were recruited for the study, including 30 patients with kidney stones and 20 normal controls (NCs). Principal component analysis and orthogonal partial least‐squares determinant analysis were carried, and 40 metabolites were found to be significantly altered in patients with kidney stones, mainly involving retinol metabolism, steroid hormone biosynthesis, and porphyrin and chlorophyll metabolism. The kidney stone group appeared to have a lower serum level of bilirubin, but a relative higher level of retinal, all‐transretinoic acid, progesterone, and prostaglandin E2 compared with those of the NC group. All the findings suggest that patients with urolithiasis have several metabolic characteristics, which are related to stone formation or compensation. These metabolites and pathways are very likely associated with development of kidney stones and should be considered as potential novel targets for treatment and prevention.

High glucose induces phosphorylation and oxidation of mitochondrial proteins in renal tubular cells: A proteomics approach

Mitochondrial dysfunction has been thought to play roles in the pathogenesis of diabetic nephropathy (DN). However, precise mechanisms underlying mitochondrial dysfunction in DN remained unclear. Herein, mitochondria were isolated from renal tubular cells after exposure to normal glucose (5.5 mM glucose), high glucose (25 mM glucose), or osmotic control (5.5 mM glucose + 19.5 mM mannitol) for 96 h. Comparative proteomic analysis revealed six differentially expressed proteins among groups that were subsequently identified by tandem mass spectrometry (nanoLC-ESI-ETD MS/MS) and confirmed by Western blotting. Several various types of post-translational modifications (PTMs) were identified in all of these identified proteins. Interestingly, phosphorylation and oxidation were most abundant in mitochondrial proteins whose levels were exclusively increased in high glucose condition. The high glucose-induced increases in phosphorylation and oxidation of mitochondrial proteins were successfully confirmed by various assays including MS/MS analyses. Moreover, high glucose also increased levels of phosphorylated ezrin, intracellular ATP and ROS, all of which could be abolished by a p38 MAPK inhibitor (SB239063), implicating a role of p38 MAPK-mediated phosphorylation in high glucose-induced mitochondrial dysfunction. These data indicate that phosphorylation and oxidation of mitochondrial proteins are, at least in part, involved in mitochondrial dysfunction in renal tubular cells during DN.

Sex differences in redox homeostasis in renal disease

Sex differences in redox signaling in the kidney present new challenges and opportunities for understanding the physiology and pathophysiology of the kidney. This review will focus on reactive oxygen species, immune-related signaling pathways and endothelin-1 as potential mediators of sex-differences in redox homeostasis in the kidney. Additionally, this review will highlight male-female differences in redox signaling in several major cardiovascular and renal disorders namely acute kidney injury, diabetic nephropathy, kidney stone disease and salt-sensitive hypertension. Furthermore, we will discuss the contribution of redox signaling in the pathogenesis of postmenopausal hypertension and preeclampsia.