Expression profiles of urine exosomal tRNA-derived small RNAs and their potential roles in calcium oxalate stone disease.

Background and objective: Exosomes have been confirmed to be implicated in the pathogenesis of calcium oxalate (CaOx) stones. tRNA-derived small RNAs (tsRNAs) are among the oldest small RNAs involved in exosome-mediated intercellular communication, yet their role in kidney stones remains unexplored. This pilot study aimed to identify differentially expressed tsRNAs (DEtsRNAs) in urine exosomes between CaOx stone patients and healthy controls and explore their potential roles in nephrolithiasis. Method: First-morning urine samples were collected from three CaOx stone patients and three healthy controls. Urinary exosomes were isolated and analyzed by high-throughput sequencing to generate the expression profiles of tsRNAs and detect DEtsRNAs. Predicted target genes of DEtsRNAs were subjected to functional enrichment analysis. The authors also combined the public dataset GSE73680 to investigate how DEtsRNAs were related to stone formation. Results: Four DEtsRNAs were significantly upregulated in CaOx stone patients compared to healthy controls. tRF-Lys-TTT-5005c was the most elevated, followed by tRF-Lys-CTT-5006c, tRF-Ala-AGC-5017b, and tRF-Gly-CCC-5004b. Bioinformatics analysis indicated that these four types of DEtsRNAs might serve distinct biological functions. Combined with data mining from the public dataset GSE73680, the authors assumed that exosomes carrying tRF-Lys-TTT-5005c and tRF-Lys-CTT-5006c could inhibit the expression of SMAD6, FBN1, and FZD1, thereby activating the BMP signaling pathway, which might induce an osteogenic-like transformation in target cells, resulting in the formation of Randall's plaques and CaOx stones. Conclusion: The authors' findings shed light on the potential roles of tsRNAs in the pathogenesis of CaOx stone disease, highlighting exosomal DEtsRNAs as promising diagnostic biomarkers and therapeutic targets in nephrolithiasis.

Expression Profiles of Claudin Gene Family Members in Patients With Recurrent Calcium Oxalate Kidney Stones.

INTRODUCTION: In this study, we aimed to evaluate and compare the expression profiles of CLDN gene family members responsible for the mechanism of stone formation in patients with recurrent calcium oxalate stones and in a control group without a history of renal stones. METHODS: Nineteen patients with recurrent calcium oxalate renal calculi who underwent percutaneous nephrolithotomy and 21 control patients without renal calculi who underwent surgery for other reasons were included in the study. The urinary calcium, oxalate, and citrate levels of the patients included in the study, as well as those in the control group, were within normal ranges. They did not have proteinuria in their urine. The biochemical parameters were also within normal limits. Biopsy samples taken from the intact renal cortex parenchymal tissue were consistent. Total RNA was isolated from biopsy samples and expression profiles of target genes (Claudin 1-4, 7, 8, 10, 14, 16, 18, 19) were determined by real-time polymerase chain reaction (PCR). RESULTS: It was determined that CLDN1 gene expression in patients with recurrent calcium oxalate kidney stones was approximately four times higher than in the control group; this difference was statistically significant (p<0.050). CLDN1 expression was also strongly positively correlated with CLDN4 (r=0.642), CLDN7 (r=0.753) and CLDN14 (r=0.651) Conclusions: We thought that CLDN1 overexpression might play a role in the pathogenesis of recurrent calcium oxalate stone formation. CLDN1 together with CLDN2, CLDN4, CLDN7, and CLDN14 are also probably responsible for this pathogenesis.

Quercus dentata Thunb. leaves extract inhibits CaOx crystallization and ameliorates ethylene glycol-induced CaOx kidney stones via the OPN/CD44 and NLRP3 pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Quercus dentata Thunb. (QD), a member of the Fagaceae family and genus Quercus, with distributions in China, Japan, Korea, and other regions. As recorded in the Ben Cao Gang Mu (Compendium of Materia Medica) and other classical Chinese medical texts, QD has been traditionally employed in Traditional Chinese Medicine (TCM) for their hemostatic and diuretic effects and has been used to treat urinary stones (Lin Zheng). It is also the main ingredient of the Mishitong capsule (MST), a Chinese patent drug, used for kidney stones and ureteral stones. Nonetheless, the specific active ingredients and the mechanisms of QD in treating kidney stones remain to be elucidated, which is crucial for advancing the scientific understanding and clinical application of this traditional medicine. AIM OF STUDY: This study aimed to identify the active constituents of QD water extract (QDWE), explore its inhibitory effects on kidney stones through in vitro and in vivo studies, and elucidate the underlying mechanisms of the OPN/CD44 axis and the NLRP3 signaling pathway to provide a full understanding of its potential as a novel treatment approach against kidney stones. MATERIALS AND METHODS: The micromolecular components in the supernatant of QDWE (QDS) were analyzed by UPLC-Q-Exactive-Orbitrap-MS and the monosaccharide composition of the macromolecular polysaccharide components in the crude polysaccharide (QDP) was determined by pre-column derivatization in HPLC. The effects of QDWE, QDS and QDP on the shape, size, and structure of calcium oxalate (CaOx) crystals in vitro were explored by XRD, FTIR and SEM. The effects of QDWE, QDS and QDP on CaOx kidney stones in SD rats induced by ethylene glycol and VD3 were compared in vivo. Furthermore, the underlying mechanisms of OPN/CD44 and NLRP3 pathways were investigated by Western blot analysis. RESULTS: There were 32 compounds identified in QDS. The monosaccharide composition ratio of QDP was Man: L-Rha: D-GlcA: D-GalA: D-Glc: D-Gal: L-Ara = 1.01: 22.52: 8.27: 38.61: 3.43: 17.80: 6.38, indicating a mixture of pectin-type acidic heteropolysaccharides. QDP had a more significant inhibitory effect on CaOx crystals in vitro than QDWE, which can inhibit the formation of CaOx monohydrate crystals (COM) and convert them into thermodynamically unstable CaOx dihydrate (COD) crystals. The high dose of QDWE exhibited significant in vivo efficacy (P < 0.05), including anti-calculus, diuretic effects, and kidney protection, marked by decreased calcification and stone formation, alongside improved kidney vitality. Furthermore, the protective effects of QDWE were demonstrated to be associated with the OPN/CD44 and NLRP3 pathways. CONCLUSION: The studies identified and analyzed the active constituents of QDWE. Among these, QDP significantly inhibited CaOx crystal generation in vitro and could be a potential component for the treatment of urinary stones in QDWE. Moreover, the results indicated that QDWE had a remarkable therapeutic effect on CaOx stones by modulating the OPN/CD44 axis to affect stone formation and the NLRP3 signaling pathway to mediate inflammation, providing an experimental basis for the mechanism of anti-urinary stone and deep development of QD.

Baicalin attenuated oxidative stress and inflammation in ethylene glycol-induced urolithiasis in adult male SD rats.

AIMS: Baicalin is a flavonoid derived from the root of the medicinal plant Scutellaria baicalensis Georgi (S. baicalensis) and is known for its various pharmacological properties. This study aimed to investigate the impact of baicalin (BAI) on the occurrence of kidney calcium oxalate crystal formation induced by ethylene glycol in male SD rats. MAIN METHODS: A rat model of renal stones was created and various concentrations of baicalin were used for intervention. Samples of urine, blood, and kidney tissue were taken from the rats, and they were euthanized for biochemical and histopathological examinations. KEY FINDINGS: Our results show that baicalin treatment improved the weight loss induced by ethylene glycol (EG) and ammonium chloride (AC) in rats. Baicalin also reduced the formation of calcium oxalate crystals and protected kidney function in rats with urolithiasis. Furthermore, it lowered the level of malondialdehyde (MDA) and elevated the activity of antioxidant enzymes compared to the stone control group. Additionally, baicalin notably alleviated renal inflammation in rats with urolithiasis. SIGNIFICANCE: The present study attributed clinical evidence first time that claiming the significant antiurolithic effect of baicalin and could be a cost-effective candidate for the prevention and treatment of urolithiasis.

Dysregulated palmitic acid metabolism promotes the formation of renal calcium-oxalate stones through ferroptosis induced by polyunsaturated fatty acids/phosphatidic acid.

The pathogenesis of renal calcium-oxalate (CaOx) stones is complex and influenced by various metabolic factors. In parallel, palmitic acid (PA) has been identified as an upregulated lipid metabolite in the urine and serum of patients with renal CaOx stones via untargeted metabolomics. Thus, this study aimed to mechanistically assess whether PA is involved in stone formation. Lipidomics analysis of PA-treated renal tubular epithelial cells compared with the control samples revealed that α-linoleic acid and α-linolenic acid were desaturated and elongated, resulting in the formation of downstream polyunsaturated fatty acids (PUFAs). In correlation, the levels of fatty acid desaturase 1 and 2 (FADS1 and FADS2) and peroxisome proliferator-activated receptor α (PPARα) in these cells treated with PA were increased relative to the control levels, suggesting that PA-induced upregulation of PPARα, which in turn upregulated these two enzymes, forming the observed PUFAs. Lipid peroxidation occurred in these downstream PUFAs under oxidative stress and Fenton Reaction. Furthermore, transcriptomics analysis revealed significant changes in the expression levels of ferroptosis-related genes in PA-treated renal tubular epithelial cells, induced by PUFA peroxides. In addition, phosphatidyl ethanolamine binding protein 1 (PEBP1) formed a complex with 15-lipoxygenase (15-LO) to exacerbate PUFA peroxidation under protein kinase C ζ (PKC ζ) phosphorylation, and PKC ζ was activated by phosphatidic acid derived from PA. In conclusion, this study found that the formation of renal CaOx stones is promoted by ferroptosis of renal tubular epithelial cells resulting from PA-induced dysregulation of PUFA and phosphatidic acid metabolism, and PA can promote the renal adhesion and deposition of CaOx crystals by injuring renal tubular epithelial cells, consequently upregulating adhesion molecules. Accordingly, this study provides a new theoretical basis for understanding the correlation between fatty acid metabolism and the formation of renal CaOx stones, offering potential targets for clinical applications.

Seminal papers in urology: urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study : Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. The Journal of urology. 1996 Mar;155(3):839 - 43.

Kidney stones, a persistent urological condition, continue to affect people globally. In this critical review, we examine the work of Borghi et al. who evaluated patients with idiopathic stone formation and randomised 99 patients to increased water intake (≥ 2 L/day) and 100 patients to usual care in a 5-year randomized controlled trial. The study examined baseline urine volume in individuals with idiopathic calcium stones, recurrence rates, and relevant biochemical factors. The study found reduced recurrence rate (12.1% vs. 27% (p = 0.008)), and time to recurrence with increased water intake (38.7 ± 13.2 months) vs. (25 ± 16.4 months) (p = 0.016). These findings inform clinical practice, contributing to the guideline recommendations that kidney stone patients should aim for fluid intake of at least 2.5 L per day to prevent stone recurrence.

Estrogen's Tissue-Specific Regulation of the SLC26A6 Anion Transporter Reveal a Phenotype of Kidney Stone Disease in Estrogen-Deficient Females: A Systematic Review.

Kidney stone formation is an intricate process that involves a disruption in the interplay of the multiple organs and systems involved in regulating the concentration of specific ions in the body. Women who have gone through menopause are susceptible to kidney stone disease. This systematic review aims to investigate the potential influence of estrogen on kidney function and oxalate homeostasis, notably through the anion transporter SLC26A6 (also known as putative anion transporter 1 or PAT1) in females. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist, a systematic search of online databases included Pubmed, ScienceDirect Journals, and Ingenta Connect Journals. Predetermined criteria to include and exclude papers, gathering articles published between 2012 and 2022, were determined. After a thorough analysis, eight articles (three cohorts, one case-control, one in vivo, one in vitro, and two cross-sectional studies) were identified for the final quality assessment review.  The eight selected and quality-assessed articles provided evidence of a directly proportional connection between estrogen and kidney function. A correlation between serum estrogen levels and the development of kidney stone disease was confirmed. Administration of ß-estradiol was shown to effectively inhibit the function of the anion transporter PAT1 in a tissue-specific manner. In the case of the kidney, estrogen was observed to down-regulate PAT1, which led to a reduction in oxalate transporting activity and, consequently, a decrease in kidney stone formation. Consensus suggests that serum estrogen levels and optimal kidney functioning are interrelated. Furthermore, analysis of the quality-assessed articles and a comprehensive literature review revealed estrogen's tissue-specific regulation of the PAT1 anion transporter aids in maintaining kidney function and anion homeostasis. Additional research is needed to solidify estrogen's role in kidney stone disease to determine its therapeutic value in clinical practice.

Oxalate­induced renal pyroptotic injury and crystal formation mediated by NLRP3­GSDMD signaling in vitro and in vivo.

Calcium oxalate kidney stone has become an urgent issue due to its high incidence and recurrence rate. Thus, it is necessary to explore for mechanisms of calcium oxalate stones formation. Previous studies demonstrated that oxalate crystals could induce the activation of nucleotide­binding domain and leucine­rich repeat­containing family pyrin domain­containing 3 (NLRP3) inflammasome and change the renal tubular epithelium adhesion. However, the type and molecular mechanism of NLRP3 inflammasome­mediated calcium oxalate stones formation still need to be further investigated. In the present study, it was confirmed that the NLRP3­gasdermin D (GSDMD) signaling was involved in oxalate­induced cell injury in vitro and in vivo. Inhibition of reactive oxygen species production could effectively prevent the NLRP3 inflammasome formation in oxalate­treated HK­2 cells. NLRP3 gene silence could inhibit the DNA damage and cellular membrane injury of HK­2 cells treated with oxalate. The ultrastructural changes of several organelles and particular structures, similar to typical cell pyroptosis, were observed in oxalate­stimulated HK­2 cells. NLRP3 gene silence could antagonize the oxalate­induced injury and ultrastructure changes. Additionally, NSA (GSDMD inhibitor) could prevent the oxalate­induced injury of membrane integrity in HK­2 cells. Moreover, oxalate crystals were significantly decreased in GSDMD­/­ mice compared with wild­type mice with glyoxylic acid. Together, NLRP3­GSDMD pathway was involved in the oxalate­induced pyroptotic injury in HK­2 cells. GSDMD and its cleavage form GSDMD­N played an important role in the oxalate­induced renal cell injury and oxalate calcium crystals formation in vitro and in vivo. This provided a new target for prevention and treatment of oxalate nephropathy and oxalate calcium stones.

The altered composition of gut microbiota and biochemical features as well as dietary patterns in a southern Chinese population with recurrent renal calcium oxalate stones.

The correlation among gut microbiota, biochemical features, and dietary patterns in recurrent stone formers has been inadequately investigated in the Chinese population. Forty-two patients with calcium oxalate stones (CaOxS group), including 34 recurrent stone formers (RS group), and 40 nonstone healthy subjects (NS group) from Changshu Hospital Affiliated with Soochow University, were prospectively recruited. Food frequency questionnaires were completed by participants, fasting vein blood was extracted, 24-h urine was collected for biochemical detection, and fecal samples were gathered for 16S ribosomal RNA (rRNA) gene sequencing. BMI; serum levels of triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), magnesium, and creatinine; and urine levels of magnesium in stone formers were significantly different from those of controls, and RS patients showed significantly low serum phosphate and high urine phosphate levels. Celery, bamboo shoots, and pickled food were the favored foods of local stone formers. Patients with recurrent stones had altered microbiota composition, with Escherichia, Fusobacterium, and Epulopiscium being the predominant pathogenic genera. The gut microbiota in RS patients had stronger functions in fatty acid and amino acid degradation but weaker functions in their biosynthesis. The pathogenic genera were positively correlated with BMI; serum levels of TGs and creatinine; urine levels of calcium, phosphate, and uric acid (UA); and celery, bamboo shoots, and pickled food intake. The abundance of Escherichia and Fusobacterium and the levels of serum magnesium and creatinine were the most relevant factors associated with stone recurrence and could be validated as biomarkers of recurrence. Our research provides a novel prevention strategy for the recurrence of renal calcium oxalate stones in the Han Chinese population of southern China.

[Features of encrustation of ureteral stents in patients with calcium oxalate and urinary acid stones].

INTRODUCTION: Stent encrustation is one of the most difficult problems that can lead to difficulties in stent removal, while ureteral obstruction can lead to renal failure. Despite the search for various preventive measures, it still remains unresolved. AIM: To study the effect of Blemaren on stent encrustation in patients with calcium-containing and uric acid stones after ureteroscopy with lithotripsy. MATERIALS AND METHODS: A total of 60 patients with ureteral stones who underwent ureteroscopy with lithotripsy in A.V. Vishnevsky National Medical Research Center of Surgery from January to August 2022, were included in the study. In all cases ureteral stents 6 Ch were placed at the end of the procedure. Patients with uric acid and calcium oxalate stones (n=48) were randomized into two groups: in the main group (n=20), they were prescribed Blemaren up to the stent removal. In the control group (n=28), patients did not receive additional therapy. To determine the severity of incrustation, we used our own classification, where the percentage of lithogenic deposits relative to the lumen of the stent was calculated. Visual assessment and microscopic examination of the removed stents were performed on days 30+/-4.1 and 60+/-7.3. RESULTS: In patients of both groups, the severity of encrustation on the 30th day after stent placement was low (up to 30%). There were no significant differences between the groups (p=0.421). The main changes were detected 60 days after stent placement. Microscopic study revealed significant differences between two groups. In patients who did not receive Blemaren, microscopic signs of encrustation of the proximal curl of the stent occurred 2.5 times more often than in the main group (p=0.001). CONCLUSIONS: 1. The number of encrusted stents in patients with calcium oxalate and uric acid stones who did not receive Blemaren significantly increases after two months. 2. Upper urinary tract drainage with a stent for a period of more than 2 months is possible if clinically necessary, however, preventive measures to reduce the risk of encrustation should be applied.

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.

A Novel Infrared Spectroscopy Method for Analysis of Stone Dust for Establishing Final Composition of Urolithiasis.

Background: The introduction of the holmium laser for lithotripsy and minimally invasive techniques in endoscopy increased the popularity of stone dusting techniques. Retrieving stone pieces for an analysis increases the economic burden of surgery and operative time. Novel methods are needed for the analysis of convenient urolithiasis composition. Objective: This study aims to assess the efficacy of the stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection (FTIR ATR) method for accurate stone composition determination from the dust specimens compared with simultaneously retrieved standard stone fragments. Design setting and participants: From July 2021 to March 2022, a total of 75 patients who received endoscopic treatment for urolithiasis were included in this study. Outcome measurements and statistical analysis: The accuracy of the FTIR ATR method was assessed via estimates of sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). The results were compared between samples of stone dust and the final stone composition. Results and limitations: Total or partial biochemical composition agreement was observed in 92.7% of cases and total agreement in 82.4% of cases when stone dust was compared with stone fragments. The highest accuracy rates were obtained for uric acid stones: sensitivity 100%, specificity 98.3%, PPV 90.9%, and NPV 100%. Identification of other types of stones was also of high accuracy, reaching up to 83.3% sensitivity and 100% specificity. Conclusions: The application of FTIR ATR spectroscopy for a stone dust analysis allows obtaining easy and cost-effective final composition of urolithiasis without a stone fragment analysis. This technique was shown to be feasible, and there is substantial potential for clinical practice. Patient summary: This study investigates a novel method that determines accurate stone composition without acquiring the pieces of stone during surgery. The results have shown that stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection provides accurate stone composition.

Inhibitory effect of fecal microbiota transplantation on renal calcium oxalate crystal deposition in rats / 中华泌尿外科杂志

Objective:To explore the effect of fecal microbiota transplantation (FMT) on the formation of renal calcium oxalate crystals in SD rats induced by oxalate mixed diet.Methods:Six male guinea pigs were fed with standard guinea pig chow for 1 month and then given a 5% oxalate diet for 14 d. The guinea pigs on the standard chow were labeled as the standard chow guinea pig (GSC group) and those on the high oxalate diet for 14 d were labeled as the guinea pig group on the high oxalate diet (GOD group). The feces of guinea pigs in the GSC and GOD groups were collected using metabolic cages. Twenty-four male SD rats were randomly divided into standard chow (SC) group, oxalate diet(OD)+ phosphate buffered saline gavage group (OD+ PBS group), OD+ FMT group and SC+ FMT group. Among them, the SC group and SC+ FMT group were fed with standard chow. The OD+ PBS group and OD+ FMT group were fed with 5% oxalate content chow. The OD+ FMT and SC+ FMT groups were given GOD group guinea pig fecal filtrate gavage for 7 days. The 24 h urine and feces of rats in each group were collected, and the intestinal microbiota of rats and guinea pigs were detected by 16sRNA detection. The urinary oxalate excretion was detected by high performance liquid chromatography. The rats and kidneys were weighed and the renal index was calculated. HE staining was used to observe the histological morphological changes of rat kidney tissue, the calcium oxalate crystal deposition in renal tissues was detected by Pizzolato staining.Results:The relative abundance of bacteria from a total of 11 families, including Muribaculaceae family and Bifidobacteriaceae family, was significantly increased in the intestinal tract of guinea pigs (GOD) from the high oxalate diet group compared to guinea pigs (GSC) from the standard chow group. The microbial diversity of the intestinal microbiota of the rats in the OD+ PBS group was reduced compared to the SC group, and the microbial diversity of the intestinal microbiota of the rats in the OD+ FMT group was restored compared to the OD+ PBS group. When given a standard chow, the intestinal microbiota of rats receiving FMT deviated from that of normal rats and was more similar to that of guinea pigs fed a high oxalate diet. In the OD+ FMT group, bacteria from a total of 18 families, including Muribaculaceae family, Erysipelotrichaceae family and Bifidobacteriaceae family, were significantly enriched, and FMT activated the intestinal microbial network represented by bacteria from Muribaculaceae family. The renal index of rats in the OD+ PBS group was significantly increased compared to the SC group (7.63±0.67 vs. 6.12±0.53, P<0.05), whereas the renal index of rats in the OD+ FMT group was significantly decreased in comparison to the OD+ PBS group (6.53±0.64 vs. 7.63±0.67, P<0.05). Urinary oxalate excretion of rats in the SC group, the OD+ PBS group, and the OD+ FMT group were (0.61±0.05), (0.89±0.04) and (0.72±0.04) μmol/ml, respectively. In the rats of the SC group no calcium oxalate crystals were seen in the kidney (0 score) and more calcium oxalate crystals were detected in the OD+ PBS group (4.83±0.41 score). The OD+ FMT group showed significantly lower calcium oxalate crystallization scores (3.17 ± 0.75 score, P<0.01) compared to the OD+ PBS group. Conclusions:FMT activated the microbial network represented by bacteria from the family Muribaculaceae in the rat intestine, significantly reduced urinary oxalate excretion and renal calcium oxalate crystal deposition in rats on a high oxalate diet.

Differential analysis of urinary metabolic abnormalities in patients with different subtypes of calcium oxalate stones / 中华泌尿外科杂志

Objective:To investigate the difference of 24h urinary metabolic abnormalities in patients with different subtypes of calcium oxalate stones.Methods:The clinical data of 120 patients with simple calcium oxalate stones admitted to the Second Affiliated Hospital of Zhengzhou University from March 2018 to May 2020 were retrospectively analyzed.There were 90 males (75.0%) and 30 females (25.0%), with the age of (49.1 ±13.5) years old, and body mass index (BMI) of (24.6 ±3.0) kg/m 2. There were 23 cases of diabetes mellitus (19.2%), 8 cases of coronary heart disease (7.0%), 36 cases of hypertension (30.0%) and 45 cases of gastrointestinal diseases (37.5%). There were 11 cases (9.2%) of low pH, 54 cases (45.0%) of hyperoxaluria, 19 cases (15.8%) of hypercalcemia, 72 cases (60.0%) of hypocitrouria, 3 cases (2.5%) of hyperuricuria, and 18 cases (15.0%) of hyperuricemia. In the 120 patients, 79 underwent ureteral soft lithotripsy, 28 underwent percutaneous nephrolithotomy, and 13 underwent extracorporeal shock wave lithotripsy. The patients were divided into calcium oxalate monohydrate stone group (COM group) and calcium oxalate dihydrate stone group (COD group). The general clinical data and urinary metabolic data of the two groups were compared. Independent risk factors for stone formation of the two groups were analyzed. Results:There were 120 cases in this study, with 90 cases in COM group and 30 cases in COD group. Urinary oxalic acid in COM group and COD group was 41.3 (30.1, 54.2) mg and 34.1 (26.6, 39.9) mg, respectively, and the difference was statistically significant ( P=0.01). The incidence of hyperoxaluria was 52.2% (47 cases) and 23.3% (7 cases), respectively, and the difference was statistically significant ( P<0.01). Urinary calcium in COD group and COM group was 6.8 (6.1, 8.8) mmol and 4.0 (2.3, 5.2) mmol, respectively, and the difference was statistically significant ( P<0.01). The incidence of hypercalcemia was 43.3% (13 cases) and 6.7% (6 cases), respectively, the difference was statistically significant ( P<0.01). The urinary phosphate in COM group and COD group was 2 063.5 (1 688.8, 2 803.2) mg and 1 231.7 (766.7, 1 740.9) mg, respectively, and the difference was statistically significant ( P<0.01). The serum uric acid level in COM group and COD group was (343.0±111.7)μmol/L and (297.6±77.6)μmol/L, respectively, and the difference was statistically significant ( P<0.05). There were no significant differences in term of age, gender, body mass index, diabetes mellitus, coronary heart disease, hypertension, gastrointestinal disease, parathyroid hormone (PTH), hemoglobin, serum creatinine, serum potassium, serum phosphorus, serum calcium, serum sodium, stone load and side between the two groups ( P>0.05). There were no significant differences in urinary sodium, urinary phosphorus, urinary magnesium, urinary citric acid and urinary uric acid levels between the two groups ( P>0.05). Binary Logistic regression analysis showed that hyperoxaluria was an independent risk factor for COM patients ( OR=4.859, P<0.01). Increased urinary phosphoric acid level was an independent risk factor for COM patients ( OR=1.001, P<0.01). Hypercalcemia was an independent risk factor for COD patients ( OR=27.856, P<0.01). Conclusions:COM calculus patients have higher urinary oxalic acid and urinary phosphoric acid levels, and are more likely to have hyperoxaluria. COD calculus patients have higher urinary calcium levels and are more likely to develop hypercalcemia.

Primary hyperoxaluria type II and organ transplantation / 器官移植

Primary hyperoxaluria type Ⅱ (PH2) is an inherited disorder of the glyoxylate metabolism caused by the gene mutation of glyoxylate reductase/hydroxypyruvate reductase (GRHPR). PH2 is characterized by recurrent nephrolithiasis and nephrocalcinosis, which may even progress into end-stage renal disease. Currently, organ transplantation is the only treatment option for PH2, which mainly includes two strategies: kidney transplantation and combined liver and kidney transplantation. Kidney transplantation yields a high risk of recurrence of oxalate nephropathy, which may cause early graft dysfunction. Combined liver and kidney transplantation could mitigate the deficiency of oxalate metabolism, whereas it yields a high risk of graft complications. PH2 is an extremely rare disorder. No consensus has been reached on the indications, surgical selection and perioperative management of organ transplantation for PH2 patients. In this article, the pathogenesis, diagnosis, monitoring and organ transplantation experience of PH2 were reviewed, aiming to divert clinicians' attention to PH2 and provide reference for determining diagnosis and treatment regimens, especially transplantation strategy for PH2 patients.

The role of autophagy in calcium oxalate kidney stone: A systematic review of the literature.

Background: Calcium oxalate kidney stone is one of the common diseases in the urinary system and has a high recurrence rate. Currently, the pathogenesis of kidney stone and the methods to prevent recurrence are still being investigated. Autophagy, as an event of cellular self-repair, has received attention in the field of kidney stone in recent years. In some current studies, autophagy has shown destructiveness and protectiveness in the pathogenesis of kidney stone. The inhibition or promotion of autophagy may be a key target for future kidney stone therapy. This systematic literature review discusses the function of autophagy in kidney stone pathogenesis in the context of current research and synthesizes the evidence analysis to provide a basis for new future therapies. Method: We systematically reviewed the literature during September 2021 according to the Preferred Reporting Items for Systematic Evaluation and Meta-Analysis (PRISMA) guidelines. Articles on studying the role of autophagy in the pathogenesis of calcium oxalate kidney stone were extracted from PubMed, MEDLINE, Embase and Scopus, including in vivo versus in vitro experiments. The study topic, language and publication date were not restricted. Two authors (Li and Zhou) searched and screened the literature. Results: We screened 18 articles from the 33 collected articles, of which 6 conducted in vitro cellular studies, four conducted animal studies, eight conducted cellular studies with animal studies, and five studied human specimens. In early studies, the literature generally concluded that autophagy is deleterious in the development of kidney stone. In 2020, the idea of the protectiveness of autophagy associated with kidney stone was first proposed and focused on targeting transcription factor EB. In addition, the interaction of autophagy with other cellular events and the regulation of signaling molecules are focused on in this paper. Conclusion: This systematic review provides advances in research on the role of autophagy in renal calculi. The current studies suggest that both upregulation and downregulation of autophagy may ameliorate injury in kidney stone models. The authors prefer the upregulation of autophagy as a future research direction for kidney stone treatment.

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.

Mechanism and influencing factors of crystal-cell interaction in the formation of calcium oxalate stones. / è‰é ¸é’™ç»“çŸ³å½¢æˆè¿‡ç¨‹ä¸­æ™¶ä½“-ç»†èƒžç›¸äº’ä½œç”¨çš„æœºåˆ¶åŠå½±å“å› ç´ .

Kidney stone is a disease with complex etiology and high incidence, and the most common chemical composition type of it is calcium oxalate stone. The formation of calcium oxalate stones includes crystal formation, crystal growth and aggregation, crystal interaction with renal tubular epithelial cells, and crystal invasion of renal interstitial extracellular matrix and so on. In these processes, crystal-cell interactions are essential for kidney crystal retention and kidney stone formation. Recently many studies have found that the interaction between crystal and renal tubular epithelial cells is closely related to various key binding molecules, endoplasmic reticulum stress of tubular cells, extracellular matrix proteins, and various lithotriptic drugs. Understanding the mechanism of crystal-cell interaction is of great significance for the prevention and early treatment of calcium oxalate stones.

Ferrostatin­1 alleviates oxalate­induced renal tubular epithelial cell injury, fibrosis and calcium oxalate stone formation by inhibiting ferroptosis.

The present study aimed to evaluate the role and mechanism of ferrostatin­1 (Fer­1) in oxalate (Ox)­induced renal tubular epithelial cell injury, fibrosis, and calcium oxalate (CaOx) stone formation. A CaOx model in mice kidneys was established via intraperitoneal injection of 80 mg/kg glyoxylic acid for 14 days. The mice were randomly divided into three groups (n=6), namely, the control (Con), the CaOx group, and the CaOx + Fer­1 group. Cultured human renal tubular epithelial cells (HK­2 cells) were randomly divided into three groups (n=3), namely, the control (Con), the Ox group, and the Ox + Fer­1 group. The levels of heme oxygenase 1 (HO­1), superoxide dismutase 2 (SOD2), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) were assessed by immunofluorescence and western blot analysis. Renal tubular injury and apoptosis were evaluated by H&E and TUNEL staining. Kidney interstitial fibrosis was evaluated by Masson and Sirius red staining, and the levels of E­cadherin, vimentin and α­SMA were detected by immunofluorescence or western blot analysis. Mitochondrial structure was observed using a transmission electron microscope. The levels of reactive oxygen species (ROS) were determined by flow cytometry and CaOx stone formation was evaluated by von Kossa staining. The results revealed that in comparison with the Con group, mitochondrial injury under glyoxylic acid treatment was observed by TEM. The expression of GPX4 and SLC7A11 in the CaOx and Ox groups was downregulated (P<0.05), whereas the expression of HO­1 and SOD2 was upregulated (P<0.05). Renal tissue damage, apoptosis of renal tubular epithelial cells, and interstitial fibrosis were increased in the CaOx and Ox groups (P<0.05). In comparison with the CaOx or Ox group, the expression of GPX4 and SLC7A11 in the CaOx + Fer­1 or Ox + Fer­1 group was upregulated (P<0.05), whereas that of HO­1 and SOD2 was downregulated (P<0.05). Renal tissue damage, apoptosis of renal tubular epithelial cells and interstitial fibrosis were decreased following Fer­1 treatment (P<0.05). The ROS level was also decreased following Fer­1 treatment. Moreover, CaOx stone formation was decreased in the CaOx + Fer­1 group (P<0.05). In conclusion, Fer­1 alleviated Ox­induced renal tubular epithelial cell injury, fibrosis, and CaOx stone formation by inhibiting ferroptosis.

Use of tetrasodium EDTA acid for the treatment of intraluminal obstruction of subcutaneous ureteral bypass devices.

OBJECTIVES: The aim of this study was to evaluate the efficacy and tolerability of a 4% tetrasodium EDTA (tEDTA) infusion protocol in the subcutaneous ureteral bypass (SUB) devices of cats with intraluminal obstruction at a veterinary teaching hospital between July 2017 and April 2020. METHODS: This was a retrospective controlled study. Cats with an obstructed SUB device underwent a 4% tEDTA infusion protocol. Obstruction of the device was diagnosed based on renal pelvic dilation, dilatation of the ureter, mineralized material within the device (cystostomy or nephrostomy catheters) seen on ultrasound, the absence of visible bubbles within the renal pelvis and/or urinary bladder following ultrasound-guided flushing of the device with saline. RESULTS: A total of 16 tEDTA infusion protocols were performed in 14 cats. The infusion protocol was considered successful in 11/16 SUB devices (68.8%). Six devices (n = 6/11; 54.5%) had recurrence of obstruction with a median time of 87 days. One or more episodes of self-limiting pollakiuria and/or hematuria following infusion was seen in eight patients (n = 8/14; 57.1%). CONCLUSIONS AND RELEVANCE: Infusions of 4% tEDTA successfully relieved intraluminal obstruction in patients with occluded SUB devices; however, the recurrence of obstruction was common. Additional studies evaluating case selection and optimal protocols are warranted.