Physiopathology and etiology of stone formation in the kidney and the urinary tract

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.

Mechanistic studies of Ca2+-induced classical pyroptosis pathway promoting renal adhesion on calcium oxalate kidney stone formation

This study aims to investigate the role of hypercalciuria and pyroptosis in the formation of calcium oxalate kidney stones. Bioinformatics analysis was performed to compare the correlation of pyroptosis scores and cell adhesion scores between Randall's plaques and normal tissues from kidney stone patients. For the in vitro experiments, we investigated the effects of high concentrations of Ca2+ on the pyroptosis and adhesion levels of renal tubular epithelial cells and examined the adhesion levels and crystal aggregation of the cells in high Ca2+ concentrations environment by knockdown and overexpression of the key pyroptosis gene, GSDMD, and we verified the effects of Ca2+ concentration on pyroptosis and adhesion levels, kidney injury, and crystal deposition by in vivo experiments. Bioinformatic results showed that the scores of pyroptosis and cell adhesion in Randall's plaques of patients with kidney stones were significantly higher than those in normal tissues, and pyroptosis was highly positively correlated with cell adhesion. In vitro and in vivo experiments showed that high concentrations of Ca2+ activated the NLRP3/Caspase-1/GSDMD pathway of pyroptosis through ROS and up-regulated the expression of adhesion-related proteins, and GSDMD could regulate the adhesion level of renal tubular epithelial cells by mediating the level of pyroptosis, thereby affecting the adhesion and deposition of calcium oxalate crystals. Our findings reveal that the Ca2+-induced classical pyroptosis pathway may be a potential mechanism to promote calcium oxalate kidney stone formation, which provides new insights into the etiology of kidney stones.

Kidney Stones as Minerals: How Methods from Geology Could Inform Urolithiasis Treatment

Despite the recent advances in minimally invasive surgery, kidney stones still pose a significant clinical challenge due to their high recurrence rate of 50% in 5-10 years after the first stone episode. Using the methods of geosciences and biology, the GeoBioMed approach treats kidney stones as biogenic minerals, offering a novel perspective on their formation and dissolution processes. In this review, we discuss kidney stones' structural and mechanical properties as emerging biomarkers of urolithiasis, emphasizing the importance of a comprehensive stone analysis in developing personalized treatment strategies. By focusing on unexplored properties like crystalline architecture, porosity, permeability, cleavage, and fracture, alongside the conventionally used composition and morphology, we show how these stone characteristics influence the treatment efficacy and the disease recurrence. This review also highlights the potential of advanced imaging techniques to uncover novel biomarkers, contributing to a deeper understanding of stone pathogenesis. We discuss how the interdisciplinary collaboration within the GeoBioMed approach aims to enhance the diagnostic accuracy, improve the treatment outcomes, and reduce the recurrence of urolithiasis.

Bioguided isolation of anti-inflammatory and anti-urolithiatic active compounds from the decoction of Cissus gongylodes leaves

ETHNOPHARMACOLOGICAL RELEVANCE

The Cissus gongylodes has traditionally been used in the diet of indigenous people in Brazil and in traditional medicine for kidney stone removal and inflammatory diseases. The active compounds responsible for these pharmacological activities are unknown.

AIM OF THE STUDY

This study aims to isolate, for the first time, the compounds in the decoction of C. gongylodes leaves responsible for their anti-inflammatory and anti-urolithiatic ethnopharmacological properties.

MATERIALS AND METHODS

The most active fractions of the C. gongylodes leaf decoction were fractionated using SPE-C18 and the compounds were purified through HPLC-UV-DAD. The decoction fractions and isolated compounds were evaluated for their anti-inflammatory and anti-urolithiatic activities. The anti-inflammatory activity was assessed using an ex vivo assay in human blood induced by LPS and calcium ionophore, measuring inflammatory mediators, PGE2 and LTB4. The anti-urolithiatic activity was evaluated using an in vitro experimental model with human urine to determine the dissolution of the most recurrent calcium oxalate (CaOx) crystals. Additionally, the decoction was chemically characterized through metabolomic analysis using UHPLC-ESI-HRMS.

RESULTS

The isolated compounds from the decoction of C. gongylodes, including rutin, eriodictyol 3'-O-glycoside, and isoquercetin, have demonstrated significant multi-target actions. These components act as anti-inflammatory agents by inhibiting the release of main inflammatory mediators, PGE2 and LTB4. Additionally, they exhibit anti-urolithiatic properties, promoting the dissolution of calcium oxalate (CaOx) crystals. Furthermore, the characterization of the decoction by UHPLC-ESI-HRMS revealed a high content of flavonoids, mainly glycosylated flavonoids.

CONCLUSIONS

The results support the traditional use of C. gongylodes decoction, identifying the compounds responsible for its anti-inflammatory and anti-urolithiatic effects. The decoction fractions and isolated compounds exhibited dual anti-inflammatory activity, effectively inhibiting key inflammatory pathways and potentially presenting fewer adverse effects while also promoting the dissolution of CaOx crystals associated with urolithiasis. The multi-target action displayed by C. gongylodes is particularly desirable in the treatment of urolithiasis, as inflammation and PGE2 production precede and contribute to the formation of CaOx crystals in the kidneys. Based on these actions, C. gongylodes emerges as a potent source of active compounds for the development of new treatments for urolithiasis.

Ultrasound of the Upper Urinary Tract

Ultrasound (US) plays a primary role in the assessment and diagnosis of renal and ureteral pathologies and their management. It is considered the first-line imaging modality for evaluation of urinary obstruction, nephrolithiasis, and urinary retention among other indications. US is also essential for evaluation of renal vasculature and assessment of renal transplantation. Contrast-enhanced US is an advanced application of US gaining its acceptance in evaluation of the renal masses.

CASR, CLDN 14, ALPL & SLC34A1 genes are associated with the risk of nephrolithiasis in Egyptian children

BACKGROUNDS

The pathophysiology of nephrolithiasis is complex, influenced by both environmental and genetic factors. Calcium is the most prevalent metabolite present in the stone matrix. Stimulating the basolateral calcium sensing receptor (CASR) in the renal tubules leads to an increase in claudin-14 expression, reducing paracellular calcium permeability and increasing urinary Ca2+ excretion. Alkaline phosphatase (ALPL) hydrolyzes the pyrophosphate to free phosphate, proposing its potential role in nephrolithiasis development. Solute carrier family 34 member 1 (SLC34A1) encodes Na+-Pi cotransporter 2a, playing a key role in renal absorption of phosphate. We aimed to detect the risk of CASR, CLDN14, ALPL, and SLC34A1 gene polymorphisms on the development of nephrolithiasis in the Egyptian children.

METHODS

We enrolled 143 children diagnosed with nephrolithiasis and 112 healthy controls. Real-time polymerase chain reaction analysis of CASR (rs1801725 G/T & rs73186030 C/T), CLDN14 (rs219780 C/T & rs199565725 AC/del), ALPL (rs149344982 A/G, rs1976403 A/C & rs1256328 C/T), and SLC34A1 (rs11746443 G/A) single-nucleotide polymorphisms (SNPs) were performed.

RESULTS

We observed that children carrying the T allele of CASR rs1801725, CLDN14 rs219780, and ALPL rs1256328 SNPs were at a greater risk of nephrolithiasis compared to the control group (p = 0.003, p < 0.001, and p = 0.001, respectively). The children with the del allele of CLDN14 rs199565725 and the ALPL rs1976403 C allele had a significantly higher risk of developing nephrolithiasis compared to the control group (p = 0.007 & p = 0.001, respectively). The individuals who have the A allele of ALPL rs149344982 and SLC34A1 rs11746443 had a significantly higher risk of nephrolithiasis compared to the control group (p < 0.001). We found that CLDN14 rs219780 CT, ALPL rs149344982 AG, ALPL rs1256328 TT, and SLC34A1 rs11746443 GA genotypes were the final predictors of nephrolithiasis in children (p < 0.05). Individuals with ATAT and GTAT haplotypes had approximately a 29- and 19-fold increased risk of nephrolithiasis.

DISCUSSION

Nephrolithiasis is a complex disease caused by genetic and environmental factors. It would be beneficial if, among patients with recurrent kidney stones, the nephrologists could identify patients at high risk who would benefit from personalized therapy, a controlled lifestyle, and regular check-ups using the necessary investigation. There are several gene polymorphisms that were identified as the risk factor for developing nephrolithiasis. We found that CASR rs1801725 G/T, CLDN14 rs199565725 AC/del & rs219780 C/T, ALPL rs149344982 A/G, rs1976403 A/C & rs1256328 C/T, SLC34A1 rs11746443 G/A were associated with an increased risk of nephrolithiasis in Egyptian children. The study limitations include a lack of detailed information on nephrolithiasis risk factors such as diet and body mass index.

CONCLUSION

CLDN14 rs219780 CT, ALPL rs149344982 AG, ALPL rs1256328 TT, and SLC34A1 rs11746443 GA genotypes were the final predictors of nephrolithiasis in children.

Based on network pharmacology, the mechanism of Dioscin in alleviating renal tubular epithelial cell injury induced by calcium oxalate crystals was explored

The commencement of kidney stone formation involves a crucial initial phase characterized by injury to renal tubular cells caused by calcium oxalate (CaOx). Dioscin (Dio) has been acknowledged for its potent anti-inflammation and anti-apoptotic properties; nevertheless, the impact and underlying Investigation into the molecular basis underlying the action of Dioscin in mitigating inflammation and apoptotic induced by exposure to calcium oxalate crystals in renal tissues remain unexplored. To comprehend the precise mechanism of Dioscin in the treatment of crystalline nephropathy, we conducted experiments utilizing a murine model of CaOx crystal deposition, induced by intraperitoneal administration of glyoxylate. An in vitro model was constructed using HK-2 cells exposed to calcium oxalate monohydrate (COM). To evaluate the effect of Dioscin on calcium oxalate crystal deposition by ROS assay, Western blotting, immunohistochemistry, Periodic Acid-Schiff staining (PAS) staining, hematoxylin-eosin (H&E) staining. Using network pharmacology and molecular docking methods, we explored the molecular mechanism of Dioscin in the treatment of CaOx-induced renal tubular epithelial cell injury. Subsequently, we conducted experiments to verify our findings. We observed a significant protective effect of Dioscin treatment against kidney oxidative stress and inflammation induced by CaOx. Then we predicted through network pharmacology that Dioscin exerts its anti-apoptotic effect through the NF-kappa B signaling pathway. Then we verified in vitro and in vivo that administration of Dioscin can alleviate the elevation of TLR4 and activation of the NF-kappa B signaling pathway induced by calcium oxalate, as well as attenuate renal apoptosis. Instead, the beneficial impact of this protection of Dioscin was reversed after overexpression of the TLR4. Dioscin has the potential to alleviate the activation of the NF-kappa B signaling pathway through TLR4, thereby exerting anti-inflammatory and anti-apoptotic effects. This study provides new ideas for the prevention and treatment of kidney stones.

The potential role of alkaline diets in prevention of calcium oxalate kidney stone formation

Formation of kidney stones is considered a major global problem. Diet plays an important role in the management of kidney stone formation. The main goal of the present research was to evaluate the protective role of fruit and vegetable mixtures as models of an alkaline diet on formation of kidney stones in rats and to conduct molecular docking study. The chemical compositions, phenolic compound profile, β-carotene content, vitamin C and antioxidant activity of both mixtures were assessed. Fruit (-42.419 ) and vegetable (-11.13) mixtures recorded a negative potential renal acid load in the presence of macro-/micro-nutrients, β-carotene and phenolic compounds; chlorogenic acid was the major content in both mixtures. Both mixtures exhibited high antioxidant activity. Molecular docking study proved that rutin displayed the highest binding affinities for glycolate oxidase (-11.8 kcal mol-1) and lactate dehydrogenase (-10.1 kcal mol-1). The kidney stone model in rats exhibited metabolic acidosis in the urinary profile through reduction of citrate; Ca, Mg and K excretion and elevation of oxalate, creatinine, creatinine clearance, uric acid, urea and protein. Additionally, there was a significant reduction in plasma Ca, Mg and K levels, while liver and kidney function parameters improved significantly. Fruit and vegetable mixtures as models of an alkaline diet proved improvement in all the parameters. Histopathological examination of kidney sections of the kidney stone model showed crystal deposition, inflammation, and severe necrosis. Kidney sections of alkaline diet models indicated mild and moderate changes. Conclusion: The results of this study proved that both alkaline diet models were effective in protecting against kidney stone formation in vivo and in molecular docking studies.

Urinary Stone Composition Analysis of 1465 Patients: The First Series from Azerbaijan

BACKGROUND

Urinary stone disease is a prevalent health issue worldwide, with varying incidence influenced by multiple factors. This study aims to provide the first comprehensive analysis of urinary stone composition in Azerbaijan.

METHODS

A retrospective study was conducted on 1465 patients, aged 1‒83 years, who underwent biochemical urinary stone analysis at the Department of Renal Diseases and Organ Transplantation, Azerbaijan State Security Service Military Hospital, between April 2015 and December 2023. Stone samples were analyzed using Fourier transform infrared (FTIR) spectroscopy. Statistical analyses were performed using the IBM® SPSS software version 29.0.

RESULTS

The cohort had a median age of 45 years, with a male-to-female ratio of 1.65:1. Calcium oxalate stones were the most common (56.2%), followed by uric acid (33.7%), struvite (5.3%), cystine (2.5%), calcium phosphate (1.9%), and xanthine (0.1%) stones. Men had a higher prevalence of calcium oxalate and uric acid stones, while women had more struvite stones. Mixed stones were common, particularly among uric acid and struvite stones. Significant differences in stone composition were observed between age groups and genders, with uric acid stones found predominantly in older individuals.

CONCLUSION

This study highlights the predominance of calcium oxalate stones and the elevated prevalence of uric acid stones in Azerbaijan, emphasizing the need for tailored diagnostic and therapeutic approaches. The high prevalence of mixed stones underscores the complexity of urinary stone disease and the need for comprehensive metabolic evaluation and individualized preventive strategies.

Bidirectional Impact of Varying Severity of Acute Kidney Injury on Calcium Oxalate Stone Formation

INTRODUCTION

Acute kidney injury (AKI) is a prevalent renal disorder. The occurrence of AKI may promote the formation of renal calcium oxalate stones by exerting continuous effects on renal tubular epithelial cells (TECs). We aimed to delineate the molecular interplay between AKI and nephrolithiasis.

METHODS

A mild (20 min) and severe (30 min) renal ischemia-reperfusion injury model was established in mice. Seven days after injury, calcium oxalate stones were induced using glyoxylate (Gly) to evaluate the impact of AKI on the formation of kidney stones. Transcriptome sequencing was performed on TECs to elucidate the relationship between AKI severity and kidney stones. Key transcription factors (TFs) regulating differential gene transcription levels were identified using motif analysis, and pioglitazone, ginkgetin, and fludarabine were used for targeted therapy to validate key TFs as potential targets for kidney stone treatment.

RESULTS

Severe AKI led to increased deposition of calcium oxalate crystals in renal, impaired kidney function, and upregulation of kidney stone-related gene expression. In contrast, mild AKI was associated with decreased crystal deposition, preserved kidney function, and downregulation of similar gene expression. Transcriptomic analysis revealed that genes associated with inflammation and cell adhesion pathways were significantly upregulated after severe AKI, while genes related to energy metabolism pathways were significantly upregulated after mild AKI. An integrative bioinformatic analysis uncovered a TF regulatory network within TECs, pinpointing that PKNOX1 was involved in the upregulation of inflammation-related genes after severe AKI, and inhibiting PKNOX1 function with pioglitazone could simultaneously reduce the increase of calcium oxalate crystals after severe AKI in kidney. On the other hand, motif analysis also revealed the protective role of STAT1 in the kidneys after mild AKI, enhancing the function of STAT1 with ginkgetin could reduce kidney stone formation, while the specific inhibitor of STAT1, fludarabine, could eliminate the therapeutic effects of mild AKI on kidney stones.

CONCLUSION

Inadequate repair of TECs after severe AKI increases the risk of kidney stone formation, with the upregulation of inflammation-related genes regulated by PKNOX1 playing a role in this process. Inhibiting PKNOX1 function can reduce kidney stone formation. Conversely, after mild AKI, effective cell repair through upregulation of STAT1 expression can protect TEC function and reduce stone formation, and activating STAT1 function can also achieve the goal of treating kidney stones.

Targeting protein receptors and enzymes for precision management of urolithiasis: A comprehensive review

Urolithiasis, characterized by the formation of solid crystalline structures within the urinary tract, presents a significant global health burden with high recurrence rates and limited treatment efficacy. Recent research has identified various protein receptors and enzymes implicated in the pathogenesis of urolithiasis, offering potential targets for therapeutic intervention. Protein receptors such as the calcium-sensing receptor and vasopressin V2 receptor play crucial roles in regulating urinary calcium excretion and water reabsorption, respectively, influencing stone formation. Additionally, modulation of receptors like the angiotensin II receptor and aldosterone receptor can impact renal function and electrolyte balance, contributing to stone prevention. Furthermore, enzymes such as urease inhibitors and xanthine oxidase inhibitors offer targeted approaches to prevent the formation of specific stone types. This review discusses the potential of targeting these receptors and enzymes for the treatment of urolithiasis, exploring associated drugs and their mechanisms of action. Despite promising avenues for personalized and precision medicine approaches, challenges such as the need for robust clinical evidence and ensuring cost-effectiveness must be addressed for the translation of these interventions into clinical practice. By overcoming these challenges, receptor-targeted therapies and enzyme inhibitors hold promise for revolutionizing the management of urolithiasis and reducing its global burden.

Heatwave and upper urinary tract stones morbidity: effect modification by heatwave definitions, disease subtypes, and vulnerable populations

As heatwave occurs with increased frequency and intensity, the disease burden for urolithiasis, a heat-specific disease, will increase. However, heatwave effect on urolithiasis subtypes morbidity and optimal heatwave definition for urolithiasis remain unclear. Distributed lagged linear models were used to assess the associations between 32 defined heatwave and upper urinary tract stones morbidity. Relative risk (RR) and attributable fraction (AF) of upper urinary tract stone morbidity associated with heatwave of different intensities (low, middle, and high) were pooled by meta-analysis. Optimal heatwave definition was selected based on the combined score of AF, RR, and quasi-Akaike Information Criterion (QAIC) value. Stratified analyses were conducted to investigate the modification effects of gender, age, and disease subtypes. Association between heatwave and upper urinary tract stones morbidity was mainly for ureteral calculus, and AF was highest for low-intensity heatwave. This study's optimal heatwave was defined as average temperature > 93rd percentile for ≥ 2 consecutive days, with AF of 7.40% (95% CI: 2.02%, 11.27%). Heatwave was associated with ureteral calculus morbidity in males and middle-aged adults. While heatwave effect was statistically insignificant in females and other age groups. Managers should develop appropriate definitions to address heatwave based on regional characteristics and focus on heatwave effects on urolithiasis.

Risk factors of urolithiasis: A hospital-based retrospective study

Aim

Urolithiasis is the most prevalent urinary tract disease, posing a global public health concern. The escalating prevalence and recurrence rates of urolithiasis are attributed to lifestyle modifications, such as reduced physical activity and dietary habits. This retrospective study aims to explore the risk factors associated with urolithiasis among individuals diagnosed with this condition.

Method

A retrospective hospital-based study involving 60 participants meeting the inclusion criteria was conducted. The participants were selected through convenience sampling from the urology, nephrology, and medical wards at Saveetha Medical College and Hospital. Demographic variables were collected, and the risk factors were assessed using a checklist on one-to-one interviews.

Results

The study unveiled that most participants (68%) were male. Eighty percent of participants had the risk factor of decreased water intake, 74% consumed excess tomatoes, 56% had a history of recurrent urinary tract infections, 64% consumed an excessive amount of salt daily, 72% experienced a decreased urine output, 53% had a habit of alcohol consumption, and 45% included milk and milk products in their daily diet. A small percentage (5%) had a family history of urolithiasis. Additionally, 6% were undergoing Siddha treatment.

Conclusion

The findings from this study underscore the significant factors contributing to urolithiasis. They can inform public health campaigns to raise awareness about lifestyle modifications, dietary changes, and hydration protocols contributing to kidney stone formation.

miR-148b-5p regulates hypercalciuria and calcium-containing nephrolithiasis

Calcium-containing stones represent the most common form of kidney calculi, frequently linked to idiopathic hypercalciuria, though their precise pathogenesis remains elusive. This research aimed to elucidate the molecular mechanisms involved by employing urinary exosomal microRNAs as proxies for renal tissue analysis. Elevated miR-148b-5p levels were observed in exosomes derived from patients with kidney stones. Systemic administration of miR-148b-5p in rat models resulted in heightened urinary calcium excretion, whereas its inhibition reduced stone formation. RNA immunoprecipitation combined with deep sequencing identified miR-148b-5p as a suppressor of calcitonin receptor (Calcr) expression, thereby promoting urinary calcium excretion and stone formation. Mice deficient in Calcr in distal epithelial cells demonstrated elevated urinary calcium excretion and renal calcification. Mechanistically, miR-148b-5p regulated Calcr through the circRNA-83536/miR-24-3p signaling pathway. Human kidney tissue samples corroborated these results. In summary, miR-148b-5p regulates the formation of calcium-containing kidney stones via the circRNA-83536/miR-24-3p/Calcr axis, presenting a potential target for novel therapeutic interventions to prevent calcium nephrolithiasis.

Bilateral Global Nephrocalcinosis in a Uremic Puppy

This study explores kidney disease in young dogs, focusing on early diagnosis, management, and the importance of staging for effective treatment. Highlighting mineral metabolism imbalances and complications such as nephrocalcinosis, the study presents a case of severe renal failure with uremic syndrome and bilateral nephrocalcinosis in a 50-day-old puppy. Despite intensive care, the puppy's condition deteriorated rapidly, leading to euthanasia. The study underscores the challenges in diagnosing and managing canine nephrocalcinosis in young animals. It emphasizes the need for further research to improve the understanding and treatment outcomes in such cases, ultimately enhancing the quality of life for animals suffering from this rare condition.

Risk factors for recurrence in pediatric urinary stone disease

BACKGROUND

Children's urinary system stones may develop from environmental, metabolic, anatomical, and other causes. Our objective is to determine the recurrence and prognosis, demographic, clinical, and etiological characteristics of children with urolithiasis.

METHODS

Medical records of patients were evaluated retrospectively. Patients' demographic data and medical history, serum/urine biochemical and metabolic analysis, blood gas analysis, stone analysis, imaging findings, and medical/surgical treatments were recorded.

RESULTS

The study included 364 patients (male 187). Median age at diagnosis was 2.83 (IQR 0.83-8.08) years. The most common complaints were urinary tract infection (23%) and urine discoloration (12%). Sixty-two percent had a family history of stone disease. At least one metabolic disorder was found in 120 (88%) of 137 patients having all metabolic analyses: hypercalciuria was found in 45%, hypocitraturia in 39%, and hyperoxaluria in 37%. Anatomical abnormalities were detected in 18% of patients. Of 58 stones analyzed, 65.5% were calcium and 20.6% were cystine stones. Stone recurrence rate was 15% (55/364). Older age (> 5 years), family history of stone disease, stone size (≥ 5 mm), and urinary system anatomical abnormalities were significantly associated with stone recurrence (p = 0.027, p = 0.031, p < 0.001, and p < 0.001, respectively). In adjusted logistic regression analysis, stone size ≥ 5 mm (OR 4.85, 95% CI 2.53-9.3), presence of urinary system anatomical abnormalities (OR 2.89, 95% CI 1.44-5.78), and family history of stone disease (OR 2.41, 95% CI 1.19-4.86) had increased recurrence rate.

CONCLUSIONS

All children with urolithiasis should be evaluated for factors affecting stone recurrence. Children at higher risk of recurrence need to be followed carefully.

Identification of novel genetic susceptibility loci for calcium-containing kidney stone disease by genome-wide association study and polygenic risk score in a Taiwanese population

Approximately 80% of kidney stone diseases contain calcium. Inherited genetic factors are among the variables that influence the development of calcium-containing kidney stone diseases (CKSD). Previous genome-wide association studies (GWAS) on stone diseases have been reported worldwide; however, these are not focused on calcium-containing stones. We conducted a GWAS to identify germline genetic polymorphisms associated with CKSD in a Medical Center in Taiwan; hence, this study was based primarily on a hospital-based database. CKSD was diagnosed using the chart records. Patients infected with urea-splitting-microorganisms and those with at least two urinary pH value below 5.5 were excluded. None of the patients had cystic stones based on stone analysis. Those over 40 years of age with no history of CKSD and no microscopic hematuria on urinalysis were considered as controls. The DNA isolated from the blood of 14,934 patients (63.7% male and 36.3% female) with CKSD and 29,868 controls (10,830 men and 19,038 women) at a medical center was genotyped for approximately 714,457 single nucleotide polymorphisms (SNPs) with minor allele frequency of ≥ 0.05. We used PLINK 1.9 to calculate the polygenic risk score (PRS) to investigate the association between CKSD and controls. The accuracy of the PRS was verified by dividing it into the training and testing groups. The statistical analyses were calculated with the area under the curve (AUC) using IBM SPSS version 22. We identified 432 susceptibility loci that reached a genome-wide threshold of P < 1.0 × 10- 5. A total of 132 SNPs reached a threshold of P < 5 × 10- 8 using a stricter definition of significance on chromosomes 4, 13, 16, 17, and 18. At the top locus of our study, SNPs in DGKH, PDILT, BCAS3, and ABCG2 have been previously reported. RN7SKP27, HDAC4, PCDH15, AP003068.2, and NFATC1 were novel findings in this study. PRS was adjusted for sex and age, resulting in an AUC of 0.65. The number of patients in the top quartile of PRS was 1.39 folds in the risk of CKSD than patients in the bottom quartile. Our data identified the significance of GWAS for patients with CKSD in a hospital-based study. The PRS also had a high AUC for discriminating patients with CKSD from controls. A total of 132 SNP loci of SNPs significantly associated with the development of CKSD. This first survey, which focused on patients with CKSD, will provide novel insights specific to CKSD and its potential clinical biomarkers.

The awareness of renal stones amongst Syrian refugees in northern Jordan

Kidney Stone Disease (KSD) is a globally prevalent condition that can be effectively addressed through proper education. This study investigated the awareness of kidney stones among refugees residing in northern Jordan. A questionnaire was administered to 487 refugees of diverse ages and socioeconomic backgrounds. Notably, 97.3% of the respondents had not attended university, and 30.8% held unskilled jobs. Upon familiarizing themselves with the signs and symptoms of kidney stones, 16.22% of men and 12.32% of women reported experiencing such symptoms. This revealed a significant association, suggesting that men might be more susceptible to developing kidney stones than women due to a lack of medical follow-up and examination for men in the camp. However, 38.77% of individuals were uncertain whether they had kidney stones. Furthermore, 38.96% of refugees were unsure about which healthcare professional to consult when experiencing kidney stone symptoms. This report highlights a serious issue with refugees' knowledge of the symptoms, causes, and treatments for kidney stones. The results indicate that Syrian refugees face challenges in acquiring adequate disease awareness, potentially related to issues of migration and war, including low levels of education, limited income, living in camps, and difficulties accessing treatments when needed. Implementing additional policies is necessary to address these challenges among Syrian refugees; however, further studies are needed to validate these findings.

The key role of major and trace elements in the formation of five common urinary stones

BACKGROUND

Urolithiasis has emerged as a global affliction, recognized as one of the most excruciating medical issues. The elemental composition of stones provides crucial information, aiding in understanding the causes, mechanisms, and individual variations in stone formation. By understanding the interactions between elements in various types of stones and exploring the key role of elements in stone formation, insights are provided for the prevention and treatment of urinary stone disease.

METHODS

This study collected urinary stone samples from 80 patients in Beijing. The chemical compositions of urinary stones were identified using an infrared spectrometer. The concentrations of major and trace elements in the urinary stones were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), respectively. The data were processed using correlation analysis and Principal Component Analysis (PCA) methods.

RESULTS

Urinary stones are categorized into five types: the calcium oxalate (CO) stone, carbonate apatite (CA) stone, uric acid (UA) stone, mixed CO and CA stone, and mixed CO and UA stone. Ca is the predominant element, with an average content ranging from 2.64 to 27.68% across the five stone groups. Based on geochemical analysis, the high-content elements follow this order: Ca > Mg > Na > K > Zn > Sr. Correlation analysis and PCA suggested significant variations in the interactions between elements for different types of urinary stones. Trace elements with charges and ionic structures similar to Ca may substitute for Ca during the process of stone formation, such as Sr and Pb affecting the Ca in most stone types except mixed stone types. Moreover, the Mg, Zn and Ba can substitute for Ca in the mixed stone types, showing element behavior dependents on the stone types.

CONCLUSION

This study primarily reveals distinct elemental features associated with five types of urinary stones. Additionally, the analysis of these elements indicates that substitutions of trace elements with charges and ion structures similar to Ca (such as Sr and Pb) impact most stone types. This suggests a dependence of stone composition on elemental behavior. The findings of this study will enhance our ability to address the challenges posed by urinary stones to global health and improve the precision of interventions for individuals with different stone compositions.

Comparison of metabolic parameters between pure-uric acid and mixed-uric acid kidney stone formers

PURPOSE

We seek to compare clinical and 24-h urine parameters between pure-uric acid (UA) and UA-CaOx stone formers in our practice and explore how any differences in metabolic profiles could suggest different prevention strategies between the two groups.

METHODS

We retrospectively reviewed patients with either pure- or mixed-UA nephrolithiasis from 2020 to 2023 at a tertiary care center. We included patients with a 24-h urine collection and a stone analysis detecting any amount of UA. Patients were organized into two cohorts: (1) those with 100% UA stones and (2) < 100% UA stones. Differences in demographic characteristics were compared between pure-UA and UA-CaOx stone formers. Twenty-four hour urine metabolic parameters as well as metabolic abnormalities were compared between the pure-uric acid and mixed-uric acid groups.

RESULTS

We identified 33 pure-UA patients and 33 mixed-UA patients. Patient demographics were similar between the groups (Table 1). Pure- and mixed-UA patients had a similar incidence of metabolic syndrome, diabetes, history of stones, and stone burden. Table 1 Demographic and baseline characteristics among pure- and mixed-uric acid stone formers Pure-uric acid stones (n = 33) Mixed-uric acid stones (n = 33) p-value Median age [IQR] 63.00 [58.00-72.50] 63.00 [53.50-68.00] 0.339 Median BMI [IQR] 28.79 [25.81-33.07] 27.96 [25.81-29.55] 0.534 Gender, n (%) 1.000  Male 21 (63.6) 21 (63.6)  Female 12 (36.4) 12 (36.4) Metabolic syndrome, n (%) 17 (51.5) 16 (48.5) 0.806 Diabetes, n (%) 13 (39.4) 12 (36.4) 0.800 History of stones, n (%) 23 (69.7) 22 (66.7) 0.792 Median total stone burden, mm [IQR] 12.00 [6.00-26.50] 13.00 [7.05-20.00] 0.995 Median serum uric acid, mg/dL [IQR] 6.20 [4.80-7.15] 5.90 [4.98-6.89] 0.582 IQR Interquartile range BMI Body Mass Index n number We found the pure-UA cohort to have 24-h lower urine volume (1.53 vs. 1.96 L/day, p = 0.045) and citrate levels (286 vs. 457 mg/day, p = 0.036). UA-CaOx stone formers had higher urinary calcium levels (144 vs. 68 mg/day, p = 0.003), higher urinary oxalate levels (38 vs. 30 mg/day, p = 0.017), and higher median urinary calcium oxalate super-saturation (3.97 vs. 3.06, p = 0.047).

CONCLUSIONS

Pure-UA kidney stone formers have different urinary metabolic parameters when compared with UA-CaOx stone formers, thus requiring different and tailored medical management.

Mrc1+ macrophage-derived IGF1 mitigates crystal nephropathy by promoting renal tubule cell proliferation via the AKT/Rb signaling pathway

Rationale: The present understanding of the cellular characteristics and communications in crystal nephropathy is limited. Here, molecular and cellular studies combined with single-cell RNA sequencing (scRNA-seq) were performed to investigate the changes in cell components and their interactions in glyoxylate-induced crystallized kidneys to provide promising treatments for crystal nephropathy. Methods: The transcriptomes of single cells from mouse kidneys treated with glyoxylate for 0, 1, 4, or 7 days were analyzed via 10× Genomics, and the single cells were clustered and characterized by the Seurat pipeline. The potential cellular interactions between specific cell types were explored by CellChat. Molecular and cellular findings related to macrophage-to-epithelium crosstalk were validated in sodium oxalate (NaOx)-induced renal tubular epithelial cell injury in vitro and in glyoxylate-induced crystal nephropathy in vivo. Results: Our established scRNA atlas of glyoxylate-induced crystalline nephropathy contained 15 cell populations with more than 40000 single cells, including relatively stable tubular cells of different segments, proliferating and injured proximal tubular cells, T cells, B cells, and myeloid and mesenchymal cells. In this study, we found that Mrc1+ macrophages, as a subtype of myeloid cells, increased in both the number and percentage within the myeloid population as crystal-induced injury progresses, and distinctly express IGF1, which induces the activation of a signal pathway to dominate a significant information flow towards injured and proliferating tubule cells. IGF1 promoted the repair of damaged tubular epithelial cells induced by NaOx in vitro, as well as the repair of damaged tubular epithelial cells and the recovery of disease outcomes in glyoxylate-induced nephrolithic mice in vivo. Conclusion: After constructing a cellular atlas of glyoxylate-induced crystal nephropathy, we found that IGF1 derived from Mrc1+ macrophages attenuated crystal nephropathy through promoting renal tubule cell proliferation via the AKT/Rb signaling pathway. These findings could lead to the identification of potential therapeutic targets for the treatment of crystal nephropathy.

Contrasting Response of Urine Stone Risk to Medical Treatment in Calcium Oxalate versus Calcium Phosphate Stone Formers

Key Points

Thiazide treatment successfully lowered urine calcium and both calcium oxalate and calcium phosphate supersaturations in both types of stone formers (SFs). Alkali therapy may not confer the same benefits on calcium phosphate SFs as it does on calcium oxalate SFs.

Background

Randomized controlled trials have shown that both thiazide diuretics and potassium citrate (K-Cit) can prevent calcium stone recurrence, but most participants formed calcium oxalate (CaOx) stones. While thiazides are expected to lower risk of calcium phosphate (CaP) stone formation, the effect of K-Cit on risk of CaP stone formation is unclear.

Methods

To study the effect of common calcium stone treatments, we analyzed the 24-hour urines of CaOx and CaP stone formers (SFs) by four treatment types: Lifestyle, K-Cit, Thiazide, or Both medications.

Results

Patients treated with thiazides reduced urine calcium in both CaOx (M =−74.4, SD =94.6 mg/d) and CaP (M =−102, SD =99.7 mg/d) SFs while those on K-Cit had no change in urine calcium. Among CaOx SFs, urine citrate rose in patients administered K-Cit with or without thiazide, but citrate did not rise significantly in CaP SFs. Urine pH rose in all CaOx SFs, but among CaP SFs, only rose in patients receiving K-Cit. CaOx supersaturation (SS) decreased in all patients who received Thiazide, and decreased among CaOx SFs treated with K-Cit. CaP SS decreased in both CaOx SFs (M =−0.46, SD =0.86) and CaP SFs (M =−0.76, SD =0.85) treated with Thiazide, except CaOx SFs who received Both. Patients treated with K-Cit alone increased CaP SS in CaOx SFs (M =0.25, SD =0.79).

Conclusions

Patients treated with Thiazide lowered urine calcium and SS in both stone groups. Patients treated with K-Cit had no significant changes in urine calcium and had a decrease in CaOx SS in CaOx SFs. The study raises questions about the best preventive treatment for patients with CaP stones and suggests that K-Cit may not confer the same benefits on CaP SFs as it does on CaOx SFs.

Association of dietary carotenoid intake with the prevalence kidney stones among the general adult population

PURPOSE

This study was to examine whether higher dietary carotenoid intake levels were associated with a lower prevalence of kidney stones.

MATERIALS AND METHODS

This study analyzed data from 2007 to 2018 National Health and Nutrition Examination Survey (NHANES) project. Dietary carotenoid intake (α-carotene, β-carotene, β-cryptoxanthin, lycopene, and lutein/zeaxanthin) was assessed using two 24-h dietary recall interviews. Multiple logistic regression and weighted quantile sum (WQS) regression were applied to examine the associations between five dietary carotenoids alone, compounds, and the prevalence of kidney stones. The dose-response relationships were analyzed by restricted cubic spline regression.

RESULTS

A total of 30,444 adults (2909 participants with kidney stones) were included in the analysis. The mean age of the participants was 49.95 years and 49.2% of the participants were male. Compared with the first quartile, the fourth quartile of α-carotene (odds ratio [OR] = 0.82 [0.73-0.92]), β-carotene (OR = 0.79 [0.70-0.89]), β-cryptoxanthin (OR = 0.88 [0.79-0.99]), and lutein/zeaxanthin (OR = 0.80 [0.71-0.91]) were significantly and inversely associated with the prevalence of kidney stones after adjusting for confounders. The dose-response analysis showed a linear relationship between five dietary carotenoid intake levels and the prevalence of kidney stones. Further WQS analysis revealed that the combination of all five dietary carotenoids was negatively associated with and the prevalence of kidney stones, with the largest effect coming from β-carotene (weight = 0.538).

CONCLUSION

Our findings indicated that higher dietary carotenoid intake levels were associated with decreased prevalence of kidney stones, and increasing the intake of foods rich in β-carotene may prevent the development of kidney stones.

Sample preparation and analysis protocols for the elucidation of structure and chemical distribution in kidney stones

Examining intact kidney stones both qualitatively and quantitatively can be difficult due to their size and fragility. Many modern analysis methods often lead to the destruction of the stone's structure during sample preparation. Preserving the structural integrity is crucial for accurately determining the chemical distribution of the components of kidney stones, which, in turn, improves our understanding of the disease's etiology. Infrared microspectroscopy and imaging play a vital role in revealing the stone's microstructure and component distribution. Consequently, this research focuses on investigating the impact of different sample preparation techniques on kidney stone analysis using infrared microspectroscopy. Specifically, it explores how polishing the surface of cross-sectioned stones influences the results. The polishing was performed utilizing abrasive discs and lapping films. A polishing device was also designed for the optimization of sample preparation. Additionally, this work involved a comparison of reflection infrared imaging with Attenuated Total Internal Reflection (ATR) infrared microspectroscopic imaging for the analysis of the microstructure of urinary stones.

Renal macrophages monitor and remove particles from urine to prevent tubule obstruction

When the filtrate of the glomerulus flows through the renal tubular system, various microscopic sediment particles, including mineral crystals, are generated. Dislodging these particles is critical to ensuring the free flow of filtrate, whereas failure to remove them will result in kidney stone formation and obstruction. However, the underlying mechanism for the clearance is unclear. Here, using high-resolution microscopy, we found that the juxtatubular macrophages in the renal medulla constitutively formed transepithelial protrusions and "sampled" urine contents. They efficiently sequestered and phagocytosed intraluminal sediment particles and occasionally transmigrated to the tubule lumen to escort the excretion of urine particles. Mice with decreased renal macrophage numbers were prone to developing various intratubular sediments, including kidney stones. Mechanistically, the transepithelial behaviors of medulla macrophages required integrin β1-mediated ligation to the tubular epithelium. These findings indicate that medulla macrophages sample urine content and remove intratubular particles to keep the tubular system unobstructed.

Study on Fu-Fang-Jin-Qian-Cao Inhibiting Autophagy in Calcium Oxalate-induced Renal Injury by UHPLC/Q-TOF-MS-based Metabonomics and Network Pharmacology Approaches

INTRODUCTION

Fu-Fang-Jin-Qian-Cao is a Chinese herbal preparation used to treat urinary calculi. Fu-Fang-Jin-Qian-Cao can protect renal tubular epithelial cells from calcium oxalateinduced renal injury by inhibiting ROS-mediated autopathy. The mechanism still needs further exploration. Metabonomics is a new subject; the combination of metabolomics and network pharmacology can find pathways for drugs to act on targets more efficiently.

METHODS

Comprehensive metabolomics and network pharmacology to study the mechanism of Fu-Fang-Jin-Qian-Cao inhibiting autophagy in calcium oxalate-induced renal injury. Based on UHPLC-Q-TOF-MS, combined with biochemical analysis, a mice model of Calcium oxalateinduced renal injury was established to study the therapeutic effect of Fu-Fang-Jin-Qian-Cao. Based on the network pharmacology, the target signaling pathway and the protective effect of Fu- Fang-Jin-Qian-Cao on Calcium oxalate-induced renal injury by inhibiting autophagy were explored. Autophagy-related proteins LC3-II, BECN1, ATG5, and ATG7 were studied by immunohistochemistry.

RESULTS

Combining network pharmacology and metabolomics, 50 differential metabolites and 2482 targets related to these metabolites were found. Subsequently, the targets enriched in PI3KAkt, MAPK and Ras signaling pathways. LC3-II, BECN1, ATG5 and ATG7 were up-regulated in Calcium oxalate-induced renal injury. All of them could be reversed after the Fu-Fang-Jin-Qian- Cao treatment.

CONCLUSIONS

Fu-Fang-Jin-Qian-Cao can reverse ROS-induced activation of the MAPK signaling pathway and inhibition of the PI3K-Akt signaling pathway, thereby reducing autophagy damage of renal tubular epithelial cells in Calcium oxalate-induced renal injury.

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

Background

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

Methods

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

Results

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

Conclusion

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

Chemical Studies of Multicomponent Kidney Stones Using the Modern Advanced Research Methods

Defining the kidney stone composition is important for determining a treatment plan, understanding etiology and preventing recurrence of nephrolithiasis, which is considered as a common, civilization disease and a serious worldwide medical problem. The aim of this study was to investigate the morphology and chemical composition of multicomponent kidney stones. The identification methods such as infrared spectroscopy (FTIR), X-ray diffraction (XRD), and electron microscopy with the EDX detector were presented. The studies by the X-ray photoelectron spectroscopy (XPS) were also carried out for better understanding of their chemical structure. The chemical mapping by the FTIR microscopy was performed to show the distribution of individual chemical compounds that constitute the building blocks of kidney stones. The use of modern research methods with a particular emphasis on the spectroscopic methods allowed for a thorough examination of the subject of nephrolithiasis.

Effects of Delayed Surgical Intervention Following Emergency Department Presentation on Stone Surgery Complexity

Introduction and Objective: Prior literature had demonstrated increased stone burden and higher rates of staged surgery in individuals of lower socioeconomic status (SES). Low SES individuals are more likely to experience delays in definitive stone surgery after initial presentation to the emergency department (ED) for kidney stones. This study aims to investigate the relationship between delays in definitive kidney stone surgery and the subsequent need for percutaneous nephrolithotomy (PNL) and/or staged surgical procedures using a statewide data set. Methods: This retrospective cohort study gathered longitudinal data from 2009 to 2018 using the California Department of Health Care Access and Information data set. Patient demographic characteristics, comorbidities, diagnosis/procedure codes, and distance were analyzed. Complex stone surgery was defined as initial PNL and/or undergoing more than one procedure within 365 days of initial intervention. Results: A total of 1,816,093 billing encounters from 947,798 patients were screened, resulting in 44,835 patients with ED visits for kidney stones followed by a urologic stone procedure. Multivariable analysis revealed that relative to patients who underwent surgery within 1 month of initial ED visit for stone disease, patients were at increased odds of undergoing complex surgery if waiting ≥6 months (odds ratio [OR] 1.18, p = 0.022), ≥1 year (OR 1.29, p < 0.001), and ≥3 years (OR 1.43, p < 0.001). Conclusions: Delays in definitive stone surgery after initial ED encounter for stone disease were associated with increased likelihood of undergoing a complex stone treatment.

Himalayan Citrus jambhiri juice reduced renal crystallization in nephrolithiasis by possible inhibition of glycolate oxidase and matrix metalloproteinases

ETHNOPHARMACOLOGICAL RELEVANCE

Citrus fruits are a very rich source of electrolytes and citric acid. They have been used traditionally for treating urinary ailments and renal stones. Citrus jambhiri is indigenously used as a diuretic.

AIM OF THE STUDY

Present study aimed at establishing the antiurolithiatic potential of the juice of Citrus jambhiri fruits along with the elucidation of the mechanism involved in the urolithiasis disease defying activity.

METHODS

The antiurolithiatic activity was established by means of nucleation, growth and aggregation assay in the in vitro settings and by means of ethylene glycol mediated calcium oxalate urolithiasis in the male Wistar rats. Docking studies were performed in an attempt to determine the mechanism of the antiurolithiatic action.

RESULTS

Present study revealed the role of C. jambhiri fruit juice in reducing nucleation, growth and aggregation of calcium oxalate crystals by possible reduction in the urinary supersaturation relative to calcium oxalate and raising the zeta potential of the calcium oxalate crystals. C. jambhiri fruit juice treatment in experimental rats produced significant amelioration of hypercalciuria, hyperoxaluria, hyperphosphaturia, hyperproteinuria, hyperuricosuria, hypocitraturia and hypomagnesiuria and ion activity product of calcium oxalate. It exhibited nephroprotection against calcium oxalate crystals induced renal tubular dilation and renal tissue deterioration. Docking studies further revealed high binding potential of the phytoconstituents of C. jambhiri viz. narirutin, neohesperidin, hesperidin, rutin and citric acid with glycolate oxidase and matrix metalloproteinase-9.

CONCLUSION

C. jambhiri fruit juice possesses excellent antiurolithiatic activity. The study reveals antiurolithiatic mechanism that involves restoration of equilibrium between the promoters and inhibitors of stone formation; and inhibition of matrix metalloproteinases and glycolate oxidase.

Mineralogy, geochemistry, and micromorphology of human kidney stones (urolithiasis) from Mersin, the southern Turkey

This study describes the primary characteristics of the selected kidney stones surgically removed from the patients at the Mersin University Hospital in the southern Turkey and interprets their formation via petrographic, geochemical, XRD, SEM-EDX, and ICP-MS/OES analyses. The analytical results revealed that the kidney stones are composed of the minerals whewellite, struvite, hydroxyapatite, and uric acid alone or in different combinations. The samples occur in staghorn, bean-shaped composite, and individual rounded particle shapes, which are controlled by the shape of the nucleus and the site of stone formation. The cross-section of the samples shows concentric growth layers due to variations in saturation, characterizing the metastable phase. Kidney stone formation includes two main stages: (i) nucleation and (ii) aggregation and/or growth. Nucleation was either Randall plaque of hydroxyapatite in tissue on the surface of the papilla or a coating of whewellite on the plaque, or crystallization as free particles in the urine. Subsequently, aggregation or growth occurs by precipitation of stone-forming materials around the plaque or coating carried into the urine, or around the nucleus formed in situ in the urine. Urinary supersaturation is the main driving force of crystallization processes; and is controlled by many factors including bacterially induced supersaturation.

An insight investigation to the antiurolithic activity of Trachyspermum ammi using the in vitro and in vivo experiments

The crude extract of Trachyspermum ammi seeds (Ta.Cr) was studied for its antiurolithic activity using the in vivo and in vitro experiments. In the in vivo experiments, Ta.Cr treatment showed a diuretic activity at the dose of 30 and 100 mg/kg and exhibited curative effect in male hyperoxaluric Wistar rats, which received 0.75% ethylene glycol (EG) in drinking water given for 3 weeks, with 1% ammonium chloride (AC) for initial three days. In the in vitro experiments, Ta.Cr delayed the slopes of nucleation and inhibited the calcium oxalate (CaOx) crystal aggregation in a concentration-dependent manner like that of potassium citrate. Ta.Cr also inhibited DPPH free radicals like standard antioxidant drug butylated hydroxytoluene (BHT), and significantly reduced cell toxicity and LDH release in Madin-Darby canine kidney (MDCK) cells, exposed to oxalate (0.5 mM) and COM (66 µg/cm²) crystals. In isolated rabbit urinary bladder strips, Ta.Cr relaxed high K⁺ (80 mM) and CCh (1 µM)-induced contractions, showing antispasmodic activity. The findings of this study suggest that the antiurolithic activity of crude extract of Trachyspermum ammi seeds may be mediated by a number of mechanisms, including a diuretic, an inhibitor of CaOx crystal aggregation, an antioxidant, renal epithelial cell protection, and an antispasmodic, thus, showing the therapeutic potential in urolithiasis, for which there is no viable non-invasive option in modern medicine.

Hyperoside Ameliorates Renal Tubular Oxidative Damage and Calcium Oxalate Deposition in Rats through AMPK/Nrf2 Signaling Axis

Background

Nephrolithiasis is a common disease that seriously affects the health and life quality of patients. Despite the reported effect of hyperoside (Hyp) against nephrolithiasis, the specific mechanism has not been clarified. Therefore, this study is aimed at investigating the effect and potential mechanism of Hyp on renal injury and calcium oxalate (CaOx) crystal deposition.

Methods

Rat and cell models of renal calculi were constructed by ethylene glycol (EG) and CaOx induction, respectively. The renal histopathological damage, CaOx crystal deposition, and renal function damage of rats were assessed by HE staining, Pizzolato staining, and biochemical detection of blood and urine parameters. MTT and crystal-cell adhesion assays were utilized to determine the activity of HK-2 cells and crystal adhesion ability, biochemical detection and enzyme-linked immunosorbent assay (ELISA) to measure the levels of oxidative stress-related substances and inflammatory factors, and western blot to test the expression levels of proteins related to the AMPK/Nrf2 signaling pathway.

Results

Briefly speaking, Hyp could improve the renal histopathological injury and impaired renal function, reduce the deposition of CaOx crystals in the renal tissue of rats with renal calculi, and decrease the adhesion of crystals to CaOx-treated HK-2 cells. Besides, Hyp also significantly inhibited oxidative stress response. Furthermore, Hyp was associated with the downregulation of malondialdehyde, lactate dehydrogenase, and reactive oxygen species and upregulation of superoxide dismutase activity. Additionally, Hyp treatment also suppressed inflammatory response and had a correlation with declined levels of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor. Further exploration of mechanism manifested that Hyp might play a protective role through promoting AMPK phosphorylation and nuclear translation of Nrf2 to activate the AMPK/Nrf2 signaling pathway.

Conclusion

Hyp can improve renal pathological and functional damage, decrease CaOx crystal deposition, and inhibit oxidative stress and inflammatory response. Such effects may be achieved by activating the AMPK/Nrf2 signaling pathway.

Polyunsaturated fatty acids ameliorate renal stone-induced renal tubular damage via miR-93-5p/Pknox1 axis

OBJECTIVES

Polyunsaturated fatty acids (PUFAs) can decrease the risk of calcium oxalate stone formation, which accounts for 80% of all renal stones. This study aimed to investigate the protective mechanisms of PUFAs against renal stones.

METHODS

Urine samples of patients with renal stones and biopsy tissue samples from patients with nephrocalcinosis were tested for miR-93-5p expression. A renal stone mouse model was established with intraperitoneal injection of glyoxylic acid, during which mice were treated with PUFAs and/or an miR-93-5p inhibitor adenovirus. Periodic acid-Schiff staining, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling staining, oil red O staining, triacylglycerol assay, and colorimetry testing were performed to assess glycogen deposition, apoptosis, lipid accumulation, blood urea nitrogen, and serum creatinine levels, respectively. Renal proximal tubular epithelial cells (human kidney 2 [HK-2]) were subjected to gain- and loss-of-function assays before calcium-oxalate monohydrate (COM) induction and PUFA treatment. Cell counting kit 8, flow cytometry, and lactate dehydrogenase activity assays were used to examine cell viability, apoptosis, and damage. A luciferase reporter gene assay verified the interaction between miR-93-5p and Pknox1, and miR-93-5p and Pknox1 levels were assessed using a reverse transcription-quantitative polymerase chain reaction and Western blot analysis.

RESULTS

miR-93-5p was downregulated in clinical samples with renal stones and negatively targeted Pknox1. PUFAs increased miR-93-5p expression and reduced apoptosis, glycogen deposition, and lipid accumulation in mice with renal stones, which were annulled by miR-93-5p downregulation. PUFAs increased proliferation and diminished apoptosis, lipid accumulation, and lactate dehydrogenase activity in COM-induced HK-2 cells, which were negated by miR-93-5p inhibition. Pknox1 overexpression reversed the effect of miR-93-5p upregulation on COM-induced HK-2 cells.

CONCLUSIONS

PUFAs repressed renal stone-induced renal tubular damage via the miR-93-5p/Pknox1 axis.

Expression and secretion of glycosylated barley oxalate oxidase in Pichia pastoris

Oxalate oxidase is an enzyme that degrades oxalate and is used in commercial urinary assays to measure oxalate levels. The objective of this study was to establish an enhanced expression system for secretion and purification of oxalate oxidase using Pichia pastoris. A codon optimized synthetic oxalate oxidase gene derived from Hordeum vulgare (barley) was generated and cloned into the pPICZα expression vector downstream of the N-terminal alpha factor secretion signal peptide sequence and used for expression in P. pastoris X-33 strain. A novel chimeric signal peptide consisting of the pre-OST1 sequence fused to pro-αpp8 containing several amino acid substitutions was also generated to enhance secretion. Active enzyme was purified to greater than 90% purity using Q-Sepharose anion exchange chromatography. The purified oxalate oxidase enzyme had an estimated Km value of 256μM, and activity was determined to be 10U/mg. We have developed an enhanced oxalate oxidase expression system and method for purification.

Primary versus deferred ureteroscopy for the management of obstructive anuria secondary to ureteric urolithiasis in children: a prospective randomized study

To compare the role of primary and deferred ureteroscopy (URS) in the management of obstructive anuria secondary to ureteric urolithiasis in pediatric patients. This prospective randomized study included 120 children aged ≤ 12 years who presented with obstructive anuria secondary to ureteric urolithiasis between March 2019 and January 2021. The children were subdivided into group A, which included children who had undergone primary URS without pre-stenting, and group B, which included children who had undergone URS after ureteric stenting. All children were clinically compensated and sepsis-free. Patients with underlying urological structural abnormalities were excluded. The operative time, improvement of renal functions, stone-free rate, and complications were compared between the two groups. At the 1-month follow-up, urine analysis; kidney, ureter, and bladder radiography; and ultrasonography were performed. The patient characteristics of both groups did not show any significant difference. Primary URS had failed in ten children (16.6%) in group A. Moreover, failure of stenting was noted in six patients (11%) in group B. The mean operative time for group B was significantly lower than that for group A (p ≤ 0.001). The stone-free rate was significantly higher in group B (p ≤ 0.001). The rate of overall complications was higher in group A. Deferred URS is preferable over primary URS in the management of obstructive anuria secondary to ureteric urolithiasis". In children because of the lower need for ureteric dilatation, higher stone- free rate, shorter procedure time, and lower complication rate.

Two independent modes of kidney stone suppression achieved by AIM/CD5L and KIM-1

The prevalence of kidney stones is increasing and its recurrence rate within the first 5 years is over 50%. No treatments that prevent the occurrence/recurrence of stones have reached the clinic. Here, we show that AIM (also called CD5L) suppresses stone development and improves stone-associated physical damages. The N-terminal domain of AIM associates with calcium oxalate crystals via charge-based interaction to impede the development of stones, whereas the 2nd and C-terminal domains capture the inflammatory DAMPs to promote their phagocytic removal. Accordingly, when stones were induced by glyoxylate in mice, recombinant AIM (rAIM) injection dramatically reduced stone development. Expression of injury molecules and inflammatory cytokines in the kidney and overall renal dysfunction were abrogated by rAIM. Among various negatively charged substances, rAIM was most effective in stone prevention due to its high binding affinity to crystals. Furthermore, only AIM was effective in improving the physical complaints including bodyweight-loss through its DAMPs removal effect. We also found that tubular KIM-1 may remove developed stones. Our results could be the basis for the development of a comprehensive therapy against kidney stone disease.

The circulating protein apoptosis inhibitor of macrophage (AIM) reduces kidney stone development and prevents build up, providing the basis for kidney stone disease therapy.

Puerarin prevents calcium oxalate crystal-induced renal epithelial cell autophagy by activating the SIRT1-mediated signaling pathway

Calcium oxalate (CaOx) crystals can activate autophagy, causing damage to renal tubular epithelial cells (TECs). Puerarin has been shown to have protective and therapeutic effects against a variety of diseases by inhibiting autophagy activation. However, the protective effect of puerarin against CaOx crystals and the underlying molecular mechanisms are unclear. Cell Counting Kit-8 (CCK-8) assays were used to evaluate the effects of puerarin on cell viability. Intracellular reactive oxygen species (ROS) levels were measured by the cell-permeable fluorogenic probe 2,7-dichlorofluorescein diacetate (DCFH-DA). Immunofluorescence, immunohistochemistry, and western blotting were used to examine the expression of SIRT1, Beclin1, p62, and LC3, and explore the underlying molecular mechanisms in vivo and in vitro. Puerarin treatment significantly attenuated CaOx crystal-induced autophagy of TECs and CaOx cytotoxicity to TECs by altering SIRT1 expression in vitro and in vivo, whereas the SIRT1-specific inhibitor EX527 exerted contrasting effects. In addition, we found that the protective effect of puerarin was related to the SIRT1/AKT/p38 signaling pathway. The findings suggest that puerarin regulates CaOx crystal-induced autophagy by activating the SIRT1-mediated signaling pathway, and they suggest a series of potential therapeutic targets and strategies for treating nephrolithiasis.

Phyllanthus Niruri L. Exerts Protective Effects Against the Calcium Oxalate-Induced Renal Injury via Ellgic Acid

Background: Urolithiasis or kidney stones is a common and frequently occurring renal disease; calcium oxalate (CaOx) crystals are responsible for 80% of urolithiasis cases. Phyllanthus niruri L. (PN) has been used to treat urolithiasis. This study aimed to determine the potential protective effects and molecular mechanism of PN on calcium oxalate-induced renal injury.

Methods: Microarray data sets were generated from the calcium oxalate-induced renal injury model of HK-2 cells and potential disease-related targets were identified. Network pharmacology was employed to identify drug-related targets of PN and construct the active ingredient-target network. Finally, the putative therapeutic targets and active ingredients of PN were verified in vitro and in vivo.

Results: A total of 20 active ingredients in PN, 2,428 drug-related targets, and 127 disease-related targets were identified. According to network pharmacology analysis, HMGCS1, SQLE, and SCD were identified as predicted therapeutic target and ellagic acid (EA) was identified as the active ingredient by molecular docking analysis. The increased expression of SQLE, SCD, and HMGCS1 due to calcium oxalate-induced renal injury in HK-2 cells was found to be significantly inhibited by EA. Immunohistochemical in mice also showed that the levels of SQLE, SCD, and HMGCS1 were remarkably restored after EA treatment.

Conclusion: EA is the active ingredient in PN responsible for its protective effects against CaOx-induced renal injury. SQLE, SCD, and HMGCS1 are putative therapeutic targets of EA.

Protective effect of bee pollen in acute kidney injury, proteinuria, and crystalluria induced by ethylene glycol ingestion in rats

Oxidative stress plays a role in hyperoxaluria-induced kidney injury and crystallization. Bee pollen is a hive product with a high content of antioxidants. The antioxidant content and protective effect of bee pollen extract (BPE) against ethylene glycol (EG) induced crystalluria, and acute kidney injury (AKI) were investigated. The effect of BPE on the EG-induced liver injury and proteinuria was also examined. Ten groups of male Wister rats were treated daily with vehicle, cystone, BPE (100, 250, and 500 mg/kg b.wt.), and group 6-9 treated with EG, EG + BPE (100, 250, and 500 mg/kg b.wt.) and group 10 EG + cystone. The dose of EG was 0.75% v/v, and the dose of cystone was 500 mg/kg b.wt. On day 30, blood and urine samples were collected for analysis. Kidneys were removed for histopathological study. The antioxidant activity of BPE was assessed, and its total phenols and flavonoids were determined. EG significantly increased urine parameters (pH, volume, calcium, phosphorus, uric acid, and protein), blood urea, creatinine, and liver enzymes (P < 0.05). EG decreased creatinine clearance and urine magnesium and caused crystalluria. Treatment with BPE or cystone mitigates EG's effect; BPE was more potent than cystone (P < 0.05). BPE increases urine volume, sodium, and magnesium compared to the control and EG treated groups. BPE reduces proteinuria and prevents AKI, crystalluria, liver injury, and histopathological changes in the kidney tissue caused by EG. BPE might have a protective effect against EG-induced AKI, crystalluria, proteinuria, and stone deposition, most likely by its antioxidant content and activity.

Medical Treatment and Prevention of Urinary Stone Disease

The pathophysiology underlying urinary stone formation remains an area of active investigation. There are many pharmacotherapies aimed at optimizing metabolic factors and reducing urinary supersaturation of stone components that play an important role in urinary stone prevention. In addition, medical expulsive therapy for ureteral stones and medical dissolution therapy for uric acid-based urinary stones are helpful treatment tools and are used alongside surgical treatments in the management of urinary stones.

The genetics of kidney stone disease and nephrocalcinosis

Kidney stones (also known as urinary stones or nephrolithiasis) are highly prevalent, affecting approximately 10% of adults worldwide, and the incidence of stone disease is increasing. Kidney stone formation results from an imbalance of inhibitors and promoters of crystallization, and calcium-containing calculi account for over 80% of stones. In most patients, the underlying aetiology is thought to be multifactorial, with environmental, dietary, hormonal and genetic components. The advent of high-throughput sequencing techniques has enabled a monogenic cause of kidney stones to be identified in up to 30% of children and 10% of adults who form stones, with ~35 different genes implicated. In addition, genome-wide association studies have implicated a series of genes involved in renal tubular handling of lithogenic substrates and of inhibitors of crystallization in stone disease in the general population. Such findings will likely lead to the identification of additional treatment targets involving underlying enzymatic or protein defects, including but not limited to those that alter urinary biochemistry.

Ethnomedicinal Plants Used for Treatment of Urolithiasis in India: A Review

Background:

The kidney stone is the most commonly observed and painful disease of the urinary tract in human being. Numerous intrinsic and extrinsic factors are responsible for the formation of kidney stone, for instance, age, sex, heredity (intrinsic factors) and climate, dietary, geography, mineral composition, and water intake (extrinsic factors). The kidney stones are categorized into calcium, struvite or magnesium ammonium phosphate, uric acid or urate, cystine and other types of stones based on chemical composition and pathogenesis. Due to the multifactorial nature of kidney stone disease, the patient may need to rely on complex synthetic medication. However, in ancient Indian history, there are several pieces of evidence where natural resources such as plants were used to remediation this lethal disease.

Objective:

The present review attempts to provide exhaustive information of ethnomedicinal and ethnopharmacological information of medicinal plants used for kidney stone in India.

Result:

Hitherto, there are a total of 258 ethnomedicinal plants from 90 different families reported using for kidney stone application. The majority of the plant species are associated with three important families: Asteraceae, Amaranthaceae, and Fabaceae. Most of the plants are from Andhra Pradesh (43 plants), followed by East Bengal (38), Jammu & Kashmir (36), Uttarakhand (31), Panjab (27), Mizoram (23), Karnataka (20), Maharashtra (20) and Assam (18). The commonly used plant parts for the herbal preparation are roots (21.22 %) followed by leaves/leaf (20.15 %), and sometimes complete plant (17.77 %) is used. The most commonly used method for the formulation is decoction (46.41 %) followed by powder (18.66 %) and then extracts (15.78 %) of different aerial and non-aerial parts of the plant. To date, the in-vitro and in-vivo activities against the kidney stone assessed for more than sixty ethnomedicinal plants.

Conclusion:

The present review epitomizes the ethnomedicinal information of medicinal plants used for kidney stone and pharmacological evidence for anti-urolithiasis activity. Most reported medicinal plants are not yet scientifically explored and need immediate attention before we lose some important species due to excessive deforestation for farming and industrial needs.

Urinary stone in a 12-year-old adolescent with new-onset type 1 diabetes and diabetic ketoacidosis

Dehydration and acidosis increase the risk for urinary stone formation. Urinary stones have been reported in three pediatric cases of diabetic ketoacidosis (DKA). A 24-h urine collection was performed for two of the three children. One patient had high urine sodium levels, while the other had low urine citrate excretion. We report the case of a 12-yr-old adolescent boy with urinary stones, new-onset type 1 diabetes mellitus (T1D), and DKA, excluding other metabolic disorders. After DKA was diagnosed, the patient received a 0.9% saline bolus and continuous insulin infusion. Hyperglycemia and ketoacidosis were well-controlled on the third day after admission. However, the patient developed abdominal pain radiating to the back. Urinary stones were suspected, and a urinalysis was performed. The patient’s urine revealed significant elevation in red blood cells and calcium oxalate crystals. Computed tomography revealed a high-density left ureteric mass, suggestive of a urinary stone. Although both the previously reported pediatric cases involved metabolic diseases, additional tests in this patient excluded metabolic diseases other than T1D. DKA may be related to the formation of calcium oxalate crystals owing to dehydration and acidosis. Therefore, physicians should consider urinary stone formation in DKA patients.

Identifying Two Novel Clusters in Calcium Oxalate Stones With Urinary Tract Infection Using 16S rDNA Sequencing

Urinary stones and urinary tract infection (UTI) are the most common diseases in urology and they are characterized by high incidence and high recurrence rate in China. Previous studies have shown that urinary stones are closely associated with gut or urine microbiota. Calcium oxalate stones are the most common type of urinary stones. However, the profile of urinary tract microorganisms of calcium oxalate stones with UTI is not clear. In this research, we firstly found two novel clusters in patients with calcium oxalate stones (OA) that were associated with the WBC/HP (white blood cells per high-power field) level in urine. Two clusters in the OA group (OA1 and OA2) were distinguished by the key microbiota Firmicutes and Enterobacteriaceae. We found that Enterobacteriaceae enriched in OA1 cluster was positively correlated with several infection-related pathways and negatively correlated with a few antibiotics-related pathways. Meantime, some probiotics with higher abundance in OA2 cluster such as Bifidobacterium were positively correlated with antibiotics-related pathways, and some common pathogens with higher abundance in OA2 cluster such as Enterococcus were positively correlated with infection-related pathways. Therefore, we speculated that as a sub-type of OA disease, OA1 was caused by Enterobacteriaceae and the lack of probiotics compared with OA2 cluster. Moreover, we also sequenced urine samples of healthy individuals (CK), patients with UTI (I), patients with uric acid stones (UA), and patients with infection stones (IS). We identified the differentially abundant taxa among all groups. We hope the findings will be helpful for clinical treatment and diagnosis of urinary stones.

Association of lead and cadmium exposure with kidney stone incidence: A study on the non-occupational population in Nandan of China

BACKGROUND

Environmental lead (Pb) and cadmium (Cd) pollution has been considered a risk factor in the etiology of kidney stones. However, the association between Pb and Cd exposure and kidney stone incidence has yet to be determined.

OBJECTIVES

This study aimed to determine a possible the association between kidney stones with Pb and Cd exposure (alone or combined) in a non-occupational population.

METHODS

Pb and Cd contaminations in soil-plant system were determined by flame atomic absorption spectrophotometry. Health risk assessment of dietary Pb or Cd intake from rice and vegetables were calculated. Kidney stones were diagnosed with urinary tract ultrasonography. Urinary cadmium (UCd) and blood lead (BPb) levels were determined by graphite-furnace atomic absorption spectrometry. Multivariate logistic regression models were constructed.

RESULTS

The hazard indexes (HI) of Pb and Cd were 7.91 and 7.31. The odds ratio (OR) was 2.83 (95 %CI:1.38-5.77) in males with high BPb (BPb ≥ 100 μg/L), compared with those with low BPb (BPb＜100 μg/L). Compared to those with low BPb and low UCd (BPb＜100 μg/L and UCd＜2 μg/g creatinine), the ORs were 2.58 (95 % CI:1.17-5.70) and 3.43 (95 % CI:1.21-9.16) in females and males with high BPb and high UCd (BPb ≥100 μg/L and UCd ≥2 μg/g creatinine), respectively. The OR was 3.16 (95 % CI:1.26-7.88) in males with high BPb and low UCd (BPb ≥ 100 μg/L and UCd ＜2 μg/g creatinine), compared to those with low BPb and low UCd.

CONCLUSIONS

Kidney stones incidence was increased by high Pb exposure in males, and by Pb and Cd co-exposure in males and females.

Effect of Aegle marmelos on the growth of brushite crystals

Background

The urinary stone formation is a very common health problem due to the prolonged medication. Calcium Hydrogen Phosphate Dihydrate (CaHPO4.2H2O, CHPD and Brushite) is one of the major constituent of urinary stone crystals. The formation and deposition of brushite crystals is the central cause of recurrent kidney stone disease among the global population. The present study aims to investigate the effect of Aegle marmelos leaves on the growth of brushite crystals to explicate the inhibitory effect of urinary stones from a different point of view.

Methods

The CHPD crystals were grown by the Single Diffusion Gel growth technique. In order to inhibit the formation of urinary stones, CHPD crystals are grown in the laboratory in the pure form and by adding the prolonged medicine A. marmelos taken especially by diabetic patients. A comparative study of the pure and A. marmelos leaves added crystals has been carried out using the Growth factor, Powder X-ray diffraction, Microstructural parameters, FTIR and SEM-EDAX.

Results

Total mass of the grown crystals is found to decrease with increasing concentrations of leaf extract of the A. marmelos. On comparing with undoped, crystalline size of the A. marmelos doped samples is reduced. Disappearance of absorption band and peak shift in the FTIR shows the incorporation of functional groups of A. marmelos. The morphology changes of the treated crystals are assessed in SEM.

Conclusions

The result shows that herbal extracts prepared from A. marmelos have good inhibitory effect on the growth of the brushite urinary stone crystals considered.