Cell death­related molecules and targets in the progression of urolithiasis (Review).

Urolithiasis is a high­incidence disease caused by calcium oxalate (mainly), uric acid, calcium phosphate, struvite, apatite, cystine and other stones. The development of kidney stones is closely related to renal tubule cell damage and crystal adhesion and aggregation. Cell death, comprising the core steps of cell damage, can be classified into various types (i.e., apoptosis, ferroptosis, necroptosis and pyroptosis). Different crystal types, concentrations, morphologies and sizes cause tubular cell damage via the regulation of different forms of cell death. Oxidative stress caused by high oxalate or crystal concentrations is considered to be a precursor to a variety of types of cell death. In addition, complex crosstalk exists among numerous signaling pathways and their key molecules in various types of cell death. Urolithiasis is considered a metabolic disorder, and tricarboxylic acid cycle­related molecules, such as citrate and succinate, are closely related to cell death and the inhibition of stone development. However, a literature review of the associations between kidney stone development, metabolism and various types of cell death is currently lacking, at least to the best of our knowledge. Thus, the present review summarizes the major advances in the understanding of regulated cell death and urolithiasis progression.

Effects of Klotho protein, vitamin D, and oxidative stress parameters on urinary stone formation and recurrence.

PURPOSE: The present study aimed to investigate the effects of α-Klotho and oxidative stress markers on urinary stone disease (USD) and demonstrate their use as biochemical markers in USD. METHODS: Among the 90 individuals included, 30 individuals were healthy controls (Group 1), 30 individuals presented with USD for the first time (Group 2), and 30 individuals demonstrated recurrent USD (Group 3). Serum levels of α-Klotho, vitamin D, malondialdehyde (MDA), total oxidant status, and total antioxidant status were determined using spectrophotometry analysis. Serum calcium and parathormone levels and 24-h urine calcium levels were measured via biochemical analysis. RESULTS: No significant intergroup difference was noted in terms of age and sex. The groups had significant differences regarding α-Klotho, oxidative stress index (OSI), MDA, and 24-h urine calcium levels. α-Klotho was a determinant of 24-h urine calcium level and OSI. An increase of 1 pg/mL in α-Klotho level appeared to result in a decrease of 8.55 mg in 24-h urine calcium level and a decrease of 0.04 Arbitrary Unit in OSI. In patients experiencing USD for the first time, α-Klotho values were < 21.83 pg/mL and showed 66% sensitivity and 64% specificity. In individuals with recurrent stone formation, α-Klotho values below 19.41 pg/mL had 60% sensitivity and 77% specificity. CONCLUSIONS: The biochemical markers investigated herein, i.e., α-Klotho, OSI, and MDA, were involved in the pathogenesis of stone formation and can be used in day-to-day clinical practices of urology clinics to identify patients at risk for both first time and recurrent USD.

Correlation between sKL and Nrf2 plasma levels and calcium oxalate urolithiasis.

OBJECTIVE: To investigate the relationship between plasma levels of sKL and Nrf2 and calcium oxalate calculi. METHODS: The clinical data of 135 patients with calcium oxalate calculi treated in the Department of Urology of the second affiliated Hospital of Xinjiang Medical University from February 2019 to December 2022, and 125 healthy persons who underwent physical examination in the same period were collected and divided into healthy group and stone group. The levels of sKL and Nrf2 were measured by ELISA. Correlation test was used to analyze the risk factors of calcium oxalate stones, logistic regression analysis was used to analyze the risk factors of calcium oxalate stones, and ROC curve was used to evaluate the sensitivity and specificity of sKL and Nrf2 in predicting urinary calculi. RESULTS: Compared with the healthy group, the plasma sKL level in the stone group decreased (111.53 ± 27.89 vs 130.68 ± 32.51), while the plasma Nrf2 level increased (300.74 ± 114.31 vs 246.74 ± 108.22). There was no significant difference in the distribution of age and sex between the healthy group and the stone group, but there were significant differences in plasma levels of WBC, NEUT, CRP, BUN, BUA, SCr, BMI, and eating habits. The results of correlation test showed that the level of plasma Nrf2 was positively correlated with SCr (r = 0.181, P < 0.05) and NEUT (r = 0.144 P < 0.05). Plasma sKL was not significantly correlated with Nrf2 (r = 0.047, P > 0.05), WBC (r = 0.108, P > 0.05), CRP (r = - 0.022, P > 0.05), BUN (r = - 0.115, P > 0.05), BUA (r = - 0.139, P > 0.05), SCr (r = 0.049, P > 0.05), and NEUT (r = 0.027, P > 0.05). Plasma Nrf2 was not significantly correlated with WBC (r = 0.097, P > 0.05), CRP (r = 0.045, P > 0.05), BUN (r = 0.122, P > 0.05), and BUA (r = 0.122, P > 0.05); (r = 0.078, P > 0.05) had no significant correlation. Logistic regression showed that elevated plasma sKL (OR 0.978, 95% CI 0.969 ~ 0.988, P < 0.05) was a protective factor for the occurrence of calcium oxalate stones, BMI (OR 1.122, 95% CI 1.045 ~ 1.206, P < 0.05), dietary habit score (OR 1.571, 95% CI 1.221 ~ 2.020, P < 0.05), and WBC (OR 1.551, 95% CI 1.423 ~ 1.424, P < 0.05). Increased NEUT (OR 1.539, 95% CI 1.391 ~ 1.395, P < 0.05) and CRP (OR 1.118, 95% CI: 1.066 ~ 1.098, P < 0.05) are risk factors for the occurrence of calcium oxalate stones. CONCLUSION: Plasma sKL level decreased and Nrf2 level increased in patients with calcium oxalate calculi. Plasma sKL may play an antioxidant role in the pathogenesis of calcium oxalate stones through Nrf2 antioxidant pathway.

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

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

The Role of Urinary Modulators in the Development of Infectious Kidney Stones.

Introduction: The pathogenesis of infectious kidney stones is poorly understood. Bacteria have been implicated in promoting infectious stones via urease production; however, there is mounting evidence indicating the relationship is more complex. The aim of our study was to characterize suspected biotic and abiotic extrinsic factors that may modulate the formation of infectious stones. Materials and Methods: A high-throughput experimental model with Griffith's artificial urine was used to test a wide variety of urinary modulators and cytoplasmic enzymes present in crude cell-free extracts (CFEs) from bacterial strains to investigate how they impact struvite and calcium (Ca) phosphate crystal production. Crystal formation was evaluated with spectrophotometry and growth curve analysis. Light microscopy and scanning electron microscopy/X-ray diffraction was used for crystal structure and composition identification. Results: The acidic urinary modulators used in this study prevented crystal formation, whereas osteopontin had a significant inhibitory effect. Addition of CFEs from Proteus mirabilis 175A and 177A resulted in Ca phosphate and struvite crystals. Of interest, Klebsiella pneumoniae and Klebsiella oxytoca produced crystals including Ca phosphate and Ca oxalate, respectively. Pseudomonas aeruginosa had no urease production detected and produced Ca phosphate crystals. Discussion: Urinary modulators can have a wide variety of effects on infectious stone formation and the role of pH is important but does not guarantee robust crystal formation. Bacterial strains can produce Ca oxalate, Ca phosphate, and struvite stones with and without urease activity. Conclusion: Various urinary modulators appear to influence the process and are worthy of further evaluation as a potential therapeutic strategy to prevent infection-related urinary stone formation. Stones formed from urinary tract infections may be a result of multiple encoded metabolic pathways and discovering these would improve our understanding of the stone-bacterial relationship.

Anti-urolithiatic Activity of Daidzin in Ethylene Glycol-Induced Urolithiasis in Rats.

Urolithiasis is a common urological disorder, which causes considerable morbidity in both genders at all age groups worldwide. Though treatment options such as diuretics and non-invasive techniques to disintegrate the deposits are available, but often they are found less effective in the clinics. In this work, we planned to investigate the ameliorative effects of daidzin against the ethylene glycol (EG)-induced urolithiasis in rats. The male albino rats were distributed into four groups (n = 6) as control (group I), urolithiasis induced by the administration of 0.75% EG (group II), urolithiasis induced rats treated with 50 mg/kg of daidzin (group III), and urolithiasis rats treated with standard drug 750 mg/kg of cystone (group IV). The urine volume, pH, and total protein in the urine were assessed. The activities of marker enzymes in both plasma and kidney tissues were analyzed using assay kits. The levels of kidney function markers such as calcium, oxalate, urea, creatinine, uric acid, magnesium, BUN, and phosphorous were estimated using assay kits. The status of antioxidants and inflammatory cytokines were also examined using kits. The renal tissues were examined by histopathological analysis. Our results revealed that the daidzin treatment effectively decreased the urine pH and protein level and increased the urine volume in the urolithiasis rats. Daidzin decreased the calcium, oxalate, uric acid, and urea, creatinine, and BUN levels and also improved the magnesium and phosphorus in the urolithiasis rats. The activities of AST, ALT, ALP, GGT, and LDH were effectively reduced by the daidzin in both serum and renal tissue. Daidzin also reduced the inflammatory marker and increased the antioxidant levels. Histopathology results also proved the therapeutic effects of daidzin. Together, our results displayed that daidzin is effective in the amelioration of EG-induced urolithiasis in rats.

Pyrrosia petiolosa Extract Ameliorates Ethylene Glycol-Induced Urolithiasis in Rats by Inhibiting Oxidative Stress and Inflammatory Response.

Objective: To study the therapeutic effect and mechanism of Pyrrosia petiolosa (P. petiolosa) extract on ethylene glycol- (EG-) induced urolithiasis in rats. Methods: Thirty SD male rats were randomly divided into five groups (n = 6): control group, EG group, and P. petiolosa group (25 mg/kg, 50 mg/kg group, and 100 mg/kg). Biochemical testing was adopted for measuring the blood and urine parameters, as well as the level of superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde acid (MDA) in kidney tissues. HE staining and ELISA were utilized to observe the histopathological changes and detect the level of IL-1ß, IL-6, MCP-1, and TNF-α in the kidney tissue, respectively. And western blot was performed for checking NOX2, NOX4, TGF-ß1, p-Smad3, Smad3, p-Smad2, and Smad2 protein expression level in kidney tissues. Results: EG could significantly increase the level of blood urea nitrogen, creatinine, and Na in serum and 24-hour urinary protein, oxalate, uric acid, creatinine, calcium, and phosphorus in urine and decreased the urine volume in rats. Whereas P. petiolosa extract was able to greatly decrease the level of related parameters in serum and urine in a dose-dependent manner, but did not affect the urine pH. In addition, P. petiolosa extract notably ameliorated EG-induced renal tissue injury. Compared with the EG group, P. petiolosa extract markedly raised the level of SOD and GSH and decreased the MDA level and the expression of NOX2 and NOX4 in the kidney tissue. Moreover, P. petiolosa extract also lowered the level of IL-1ß, IL-6, MCP-1, and TNF-α in EG-stimulated kidney tissue and inhibited the protein level of EG-induced TGF-ß1, p-Smad3, and p-Smad2 in a concentration-dependent manner. Conclusion: P. petiolosa extract can improve EG-induced urolithiasis in rats by inhibiting oxidative stress, inflammatory response, and the activation of TGF-ß pathway.

Subcutaneous Adipose Tissue Accumulation Is an Independent Risk Factor of Urinary Stone in Young People.

Background: Urinary stones usually start at a young age and tend to recur. Therefore, preventing stone occurrence and recurrence in young people is crucial. We aimed to investigate the association between subcutaneous adipose tissue, visceral adipose tissue, and stone episodes in young people. Methods: We retrospectively studied patients aged below 40 years with kidney or ureteral stones. Data on demographic and metabolic characteristics, urolithiasis history, subcutaneous fat area (SFA), and visceral fat area (VFA) were collected. We evaluated the association between SFA or VFA and the occurrence or recurrence of stone episodes using binary logistic regression and Poisson regression analyses. Results: In total, 120 patients were included. Abdominal obesity, overweight or obesity, dyslipidemia, metabolic syndrome, SFA, and VFA increased with the number of stone episodes (all p < 0.05). The increase in SFA was independently associated with episode occurrence (p = 0.015). Patients with an SFA > 97 cm2 had a higher risk of episode occurrence. SFA and VFA accumulation were independently associated with episode recurrence (all p < 0.05), and SFA had a stronger association than VFA did. Conclusions: In young people, SFA accumulation is an independent and early risk factor for the occurrence and recurrence of stone episodes. Subcutaneous fat could be a convenient and effective indicator to assess the risk of stone episodes before the development of metabolic disorders.

Endothelial Dysfunction: An Intermediate Clinical Feature between Urolithiasis and Cardiovascular Diseases.

An epidemiological relationship between urolithiasis and cardiovascular diseases has extensively been reported. Endothelial dysfunction is an early pathogenic event in cardiovascular diseases and has been associated with oxidative stress and low chronic inflammation in hypertension, coronary heart disease, stroke or the vascular complications of diabetes and obesity. The aim of this study is to summarize the current knowledge about the pathogenic mechanisms of urolithiasis in relation to the development of endothelial dysfunction and cardiovascular morbidities. METHODS: A non-systematic review has been performed mixing the terms "urolithiasis", "kidney stone" or "nephrolithiasis" with "cardiovascular disease", "myocardial infarction", "stroke", or "endothelial dysfunction". RESULTS: Patients with nephrolithiasis develop a higher incidence of cardiovascular disease with a relative risk estimated between 1.20 and 1.24 and also develop a higher vascular disease risk scores. Analyses of subgroups have rendered inconclusive results regarding gender or age. Endothelial dysfunction has also been strongly associated with urolithiasis in clinical studies, although no systemic serum markers of endothelial dysfunction, inflammation or oxidative stress could be clearly related. Analysis of urine composition of lithiasic patients also detected a higher expression of proteins related to cardiovascular disease. Experimental models of hyperoxaluria have also found elevation of serum endothelial dysfunction markers. CONCLUSIONS: Endothelial dysfunction has been strongly associated with urolithiasis and based on the experimental evidence, should be considered as an intermediate and changeable feature between urolithiasis and cardiovascular diseases. Oxidative stress, a key pathogenic factor in the development of endothelial dysfunction has been also pointed out as an important factor of lithogenesis. Special attention must be paid to cardiovascular morbidities associated with urolithiasis in order to take advantage of pleiotropic effects of statins, angiotensin receptor blockers and allopurinol.

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 urease­producing 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.

Age-Specific Excretion of Calcium, Oxalate, Citrate, and Glycosaminoglycans and Their Ratios in Healthy Children and Children with Urolithiasis.

We analyzed children with urolithiasis with age- and gender-matched healthy children. Calcium (mmol/mmol creatinine) and the calcium/citrate ratio (mol/mmol) are the only variables that differentiate children before puberty from healthy children (ROC analysis confirmed only calcium/citrate as a significant variable with cut-off value > 0.84). Peri-pubertal children are distinguished from age- and gender-matched healthy children by the following variables: citrate (mmol/mol creatinine), calcium/citrate (mol/mmol), oxalate/glycosaminoglycans (mmol/g), oxalate/citrate ratios (mmol/mmol) and oxalate/(citrate × glycosaminoglycans) (mol oxalate × mol creatinine)/(mol citrate × g glycosaminoglycans). All variables were confirmed by ROC analysis with cut-off values ≤ 327.87, >1.02, >11.24, >0.12 and >0.03, respectively. These results indicate a different risk of urinary stones development before puberty vs. pubertal/postpubertal children and increasing importance (deficiency) of citrate and glycosaminoglycans in such children. J48 classifier confirmed the importance of the oxalate/(citrate × glycosaminoglycans) and the calcium/citrate ratios (Ox/Cit × GAG 0.22 and Cit/GAG 0.612) with the practically applicable classification tree for distinguishing between pubertal/postpubertal children with urolithiasis with age- and gender-matched healthy children.

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

PURPOSE: To evaluate the characteristics of urinary stone composition in a Korean population using a large database of stone composition. MATERIALS AND METHODS: From January 1, 2014, to June 30, 2019, a total of 33,078 urinary stone composition data were analyzed. Stone composition was classified into four main groups: calcium oxalate (CaOx), struvite, uric acid (UA), and calcium phosphate (CaP). We examined the relationship between stone composition and sex, age, geographic region, calendar month, and season. RESULTS: The CaOx group (46.41%) was the largest, followed by the struvite group (29.66%), UA group (19.61%), and CaP group (4.32%). The CaOx group tended to decrease with age, but the UA group increased with age. Also, the CaOx group had the highest percentage in summer and the lowest in spring (p<0.001). The struvite and CaP groups had higher percentages of females than males (struvite: 36.6% vs. 25.7%, p<0.001; CaP: 6.2% vs. 3.3%, p<0.001). Conversely, the UA stones were more common in males than in females (24.5% vs. 11.0%, p<0.001). The UA group had the lowest percentage in the capital region (p<0.001). The total male-to-female ratio decreased over time from 1.95:1 in 2014 to 1.67:1 in 2018 (p<0.001). CONCLUSIONS: There were differences for each stone composition in the percentages according to sex, age, geographic region, month, and season. Identifying these differences based on the stone composition is vital for the treatment and prevention of urinary stones.

Protective effect of apigenin on ethylene glycol-induced urolithiasis via attenuating oxidative stress and inflammatory parameters in adult male Wistar rats.

AIMS: Apigenin (4',5,7-trihydroxyflavone) is one of the subclasses of flavonoids and has various pharmacological effects. The present work was carried out to study the effect of apigenin on ethylene glycol-induced kidney damage in male Wistar rats. MAIN METHODS: We evaluated the effects of apigenin orally administrated in normal and urolithiatic rats. Animals were assigned to nine groups in random: normal control; apigenin alone (0.005, 0.01, and 0.02 g/kg bw); urolithiatic control (0.75% ethylene glycol and 1.0% ammonium chloride in drinking water); apigenin (0.005, 0.01, and 0.02 g/kg bw) plus ethylene glycol and ammonium chloride; and cystone (0.75 g/kg bw) plus ethylene glycol and ammonium chloride. At the end of 28th day of treatment, animals were sacrificed for biochemical and histopathological assays. KEY FINDINGS: Our results indicated that the apigenin treatment decreased the formation of urinary stones in urolithiatic rats. Also, apigenin reduced the generation of malondialdehyde and enhanced antioxidant enzymes activities in the kidney homogenate of rats. It also caused a significant decrease in the calcium oxalate crystals numbers in urinary sample of rats with ethylene glycol-induced hyperoxaluria. These findings were supported by histopathological examinations. SIGNIFICANCE: Based on the results obtained, apigenin attenuate ethylene glycol-related kidney damage in male Wistar rats. Although the underlying mechanism of apigenin effect has not been determined, reduction of urinary levels of stone-producing constituents, antioxidant activities, and inhibition of TGF-ß signaling may be involved.

Urinary Diversion: Core Curriculum 2021.

Urinary diversion after cystectomy has been a historical standard for the treatment of numerous benign and malignant diseases of the bladder. Since the first published description in the early 1900s, improvements in surgical technique and a better understanding of the metabolic sequelae postoperatively have greatly enhanced patient outcomes. Both continent and incontinent diversions are available to patients after cystectomy. In appropriately selected patients, orthotopic neobladder reconstruction can offer preservation of body image and continence, and continent cutaneous diversions represent a reasonable alternative. Conduit diversion, which remains the most commonly performed diversion technique, is ideal for patients who would benefit from a less morbid surgical procedure that negates the need for self-catheterization. This installment of the Core Curriculum in Nephrology outlines numerous aspects of urinary diversion, in which a multidisciplinary approach to postoperative management at the intersection of nephrology and urology is required to effectively optimize patient outcomes. This article includes a discussion of the various reconstructive options after cystectomy as well as a comprehensive review of frequently encountered short-term and long-term metabolic abnormalities associated with altered electrolyte and acid-base homeostasis.

Evaluations of the curative efficacy of G. fruticosus solvent extracts in experimentally induced nephrolithiatic Wistar male rats.

BACKGROUND: In Ethiopian folk medicine, there is a claim that medicinal plants can treat urolithiasis although there is insufficient scientific evidence. The objective of this study was to evaluate the curative efficacy of Gomphocarpus fruticosus extracts in experimentally induced nephrolithiatic rats. METHODS: Urolithiasis was induced in male Wistar rats by feeding ethylene glycol in drinking water for 28 days. The curative effects were evaluated after oral administrations of 200 mg/kg of the extracts from 15 to 28 days. Urine samples were collected 1 day before sacrificing the rats. Blood, liver and kidney samples were gathered under anaesthetic condition at day 28. Crystals in the urine were also analyzed by light microscopy. RESULTS: G. fruticosus EtOAc extract reduced significantly the level of sodium (P < 0.001), whereas it was significantly elevated the levels of magnesium and citrate (P < 0.01) compared to lithiatic control. G. fruticosus BuOH extract lowered the levels of potassium (P < 0.01), calcium and phosphate in urolithiatic rats. It was also observed that G. fruticosus EtOAc extract decreased the level of oxalate in the urine (P < 0.001), whereas it was increased the levels of magnesium (P < 0.05) and citrate (P < 0.01) in serum analysis after exposure to BuOH extract. In the kidneys, CaOx crystal deposits were reduced significantly by G. fruticosus EtOAc extract (P < 0.01). CONCLUSION: It has been noted that G. fruticosus EtOAc extract was potent in treating urolithiasis. However, further study is required to assess the efficacy of the active compounds against urolithiasis.

Antiurolithic efficacy of a phenolic rich ethyl acetate fraction of the aerial parts of Aerva lanata (Linn) Juss. ex Schult. in ethylene glycol induced urolithic rats.

OBJECTIVES: The study was carried out to evaluate the in vivo antiurolithic efficaciousness of an ethyl acetate fraction of Aerva lanata (EAFAL) derived from the hydromethanolic extract of its aerial parts (HMEAL). METHODS: In vivo pharmacological potency of EAFAL was assessed by ethylene glycol (EG) induced urolithiasis model in male Wistar albino rats. Urine samples of the animals were analysed for physical parameters, stone promoters, inhibitors along with an evaluation of the biochemical parameters of serum and kidneys. Histopathological investigation of the kidneys was done. The fraction was further subjected to LC-MS and HPLC for its phytochemical evaluation. KEY FINDINGS: EAFAL demonstrated a significant antiurolithic effect by a restoration of the balance between urinary promoters and inhibitors along with an amelioration of the urinary pH. The abnormally elevated levels of serum nitrogenous substances, calcium, albumin, globulin, total protein along with altered renal calcium, oxalate and uric acid were also alleviated significantly followed by an improvement of the histopathological aberrancies. Phytochemical analysis showed evidence of phenolic components and flavonoids. CONCLUSIONS: The current findings prove the beneficial role of phenolic and flavonoid rich EAFAL in ameliorating urolithiasis induced abnormalities of urine, serum and kidneys.

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.

Role of ferroptosis induced by a high concentration of calcium oxalate in the formation and development of urolithiasis.

Ferroptosis is an iron­dependent lipid peroxidation process. Although the involvement of ferroptosis in kidney diseases has recently been reported, the association between ferroptosis and urolithiasis remains unclear. The present study examined the effects of ferroptosis on calcium oxalate (CaOx) crystal­induced renal tubular epithelial cell injury in vivo and in vitro. First, renal tubular epithelial cells were exposed to various concentrations of CaOx. By measuring cell viability, Fe2+ levels, lipid peroxidation levels and the levels of ferroptosis­related proteins, it was identified that the relative expression of the ferroptosis agonist proteins, p53, long­chain acyl­CoA synthetases (ACSL4), transferrin (TF) and transferrin receptor (TRC), increased, while the relative expression of the ferroptosis inhibitory proteins, solute carrier family 7 member 11 (SLC7A11, XCT) and glutathione peroxidase 4 (GPX4), decreased significantly. Furthermore, the levels of Fe2+ and lipid peroxidation gradually increased, while cell viability significantly decreased. From these results, it was noted that the extent of CaOx­induced ferroptosis activation and cell injury was dependent on the CaOx concentration. To further investigate the association between ferroptosis and renal tubular epithelial cell injury, the ferroptosis agonist, erastin, and the ferroptosis inhibitor, ferrostatin­1, were used to regulate the degree of ferroptosis at the same CaOx concentration in in vivo and in vitro experiments. CaOx­induced ferroptosis and damage to renal tubular epithelial cells and renal tissue were investigated. Finally, it was identified that through the regulation of ferroptosis levels, renal tubular epithelial cell injury increased significantly when the ferroptosis level increased, and vice versa. On the whole, the present results indicated that ferroptosis is essential for renal tubular epithelial cell injury induced by CaOx crystals. This finding is highly significant and promotes the further investigation of the association between ferroptosis and urolithiasis.

Integration of exome sequencing and metabolic evaluation for the diagnosis of children with urolithiasis.

PURPOSE: To investigate the prevalence of inherited causes in an early onset urolithiasis cohort and each metabolic subgroup. METHODS: A retrospective analysis of both metabolic and genomic data was performed for the first 105 pediatric urolithiasis patients who underwent exome sequencing at our hospital from February 2016 to October 2018. Measurements included the diagnostic yield of exome sequencing in the entire cohort and each metabolic subgroup (hyperoxaluria, hypocitraturia, hypercalciuria, hyperuricosuria and cystine stone subgroups). The conformity between molecular diagnoses and metabolic evaluation was also evaluated. RESULTS: The present study involved a cohort of 105 pediatric patients with urolithiasis, from which diagnostic variants were identified in 38 patients (36%), including 27 primary hyperoxaluria and 11 cystinuria. In the metabolic subgroup analyses, 41% hyperoxaluria cases were primary hyperoxaluria caused by monogenic defects, and 100% of the causes of cystine stones could be explained by monogenic defects. However, no appropriate inherited causes were identified for hypocitraturia, hypercalciuria, or hyperuricosuria in the cohort. A high conformity (100%) was obtained between the molecular diagnoses and metabolic evaluation. CONCLUSION: Exome sequencing in a cohort of 105 pediatric patients with urolithiasis yielded a genetic diagnosis in 36% of cases and the molecular diagnostic yield varies substantially across different metabolic abnormalities.