Calcium Oxalate Stone Formation Research Articles

Urine pH and Citrate as Predictors of Calcium Phosphate Stone Formation.

Urinary parameters including urine pH and citrate are recognized as critical in the pathophysiology of calcium-based stones. The factors contributing to variation in these parameters between calcium oxalate and calcium phosphate stone formers are however not well understood. In this study using readily available laboratory data, we explore these differences to delineate the odds of forming calcium phosphate (CaP) versus calcium oxalate (CaOx) stones. In this single-center retrospective study, we compared serum and urinary parameters between adult CaP stone formers (SF), CaOx SF, and non-stone formers (NSF). Urine pH was higher and urine citrate lower in CaP SF compared to same-sex CaOx SF and NSF. In CaP SF, higher urine pH and lower citrate were independent of markers of dietary acid intake and gastrointestinal alkali absorption, suggesting abnormal renal citrate handling and urinary alkali excretion. In a multivariable model, urine pH and urine citrate were most discriminatory between CaP SF and CaOx SF (Receiver Operating Characteristic Area Under the Curve of 0.73 and 0.65 respectively). An increase in urine pH by 0.35, a decrease in urine citrate by 220 mg/day, a doubling of urine calcium, and female sex all independently doubled the risk of CaP compared to CaOx. High urine pH and hypocitraturia are two clinical parameters that distinguish the urine phenotype of CaP SF from CaOx SF. The alkalinuria is due to intrinsic differences in the kidney independent of intestinal alkali absorption and is accentuated in the female sex.

Comparison of two software programs used to determine the relative supersaturation of urine ions.

Relative supersaturation (RSS) values for urine crystals are a measure of the risk of urinary stone formation and have been shown to be lowered in foods shown to aid in the management of urolithiasis. In order to calculate RSS in pets, computer programs have been developed to calculate RSS and aid in the understanding of stone formation in veterinary medicine. However, some older programs have not been updated for use in animals, and the specific coefficients used are not publically available. One of the first RSS programs was developed in BASIC computer language and published in 1985 which was called EQUIL2. The EQUIL2 program was updated to a compiled version compatible with a PC platform. However, the formulas could not be read or altered. This study evaluates a new program with known coefficients to the original EQUIL2 program. The RSS values of the two programs were compared through a t-test, calculating the r2 from correlation analysis, Lin's concordance correlation coefficient, and by a Bland-Altman analysis of outputs from the two programs using urine samples from healthy dogs and cats. Our results show that for both magnesium ammonium phosphate (struvite) and calcium oxalate, the RSS values of the original program could be calculated from the new programs RSS values. Although the actual RSS values were different (as might be expected through the use of the updated coefficients and different thermodynamic stability constants in the calculations) the results were highly correlated, finding elevations and reductions in RSS proportionally in the same urine samples. The current work creates a foundation for using the modernized program to calculate RSS and provides a shared method for understanding the risk of struvite and calcium oxalate stone formation.

Impact of body mass index on size and composition of urinary stones: a systematic review and meta-analysis.

Several studies have explored the impact of BMI on size and composition of urinary stones. Because there were controversies, a meta-analysis was necessary to be carried out to provide some evidence of the relationship of BMI and urolithiasis. PubMed, Medline, Embase, Web of Science databases, and the Cochrane Library were searched up to August 12th 2022 for eligible studies. The urolithiasis patients were summarized into two groups: BMI < 25 and ≥ 25 kg/m2. Summary weighted mean difference (WMD), relative risk (RR) and 95% confidence intervals (CI) were calculated through random effects models in RevMan 5.4 software. A total of fifteen studies involving 13,233 patients were enrolled in this meta-analysis. There was no significant correlation of BMI and size of urinary stone (WMD -0.13mm, 95% CI [-0.98, 0.73], p = 0.77). Overweight and obesity increased the risk of uric acid stones in both genders and in different regions (RR=0.87, [95% CI] = 0.83, 0.91, p<0.00001). There was a higher risk of calcium oxalate stones formation in overweight and obesity group in total patients (RR=0.95, [95% CI] = 0.91, 0.98, p = 0.006). The relationship of BMI and calcium phosphate was not observed in this meta-analysis (RR=1.12, [95% CI] = 0.98, 1.26, p = 0.09). Sensitivity analysis was performed and indicated similar results. The current evidence suggests a positive association between BMI and uric acid and calcium oxalate stones. It would be of great guiding significance to consider losing weight when treating and preventing urinary stones.

Is hyperuricosuria really a risk factor for calcium oxalate stone formation?

In the seventies of the last century the term hyperuricosuric calcium oxalate (CaOx) urolithiasis has been coined. Allopurinol significantly decreased the recurrence in CaOx stone formers. Nevertheless, the role of hyperuricosuria has been questioned. Other mechanisms could have decreased the risk for recurrence. The underlying mechanisms are not clear. All these studies have been performed with only a limited number of patients. We studied n=2,480 consecutive patients with CaOx stones. For stone analysis, x-ray diffraction was used. The following parameters were examined in all patients: age, sex, body mass index (BMI), arterial blood pressure, stone episodes, diabetes mellitus; blood: creatinine, glucose, uric acid, calcium, sodium and potassium; urine: pH, volume, calcium, uric acid, citrate, ammonia and urea. According to the uric acid excretion (UAE), patients were divided into two groups: 1. UAE &gt; 4 mmol/d (hyperuricosuria), 2. UAE ≤ 4 mmol/d (normouricosuria). We observed significant correlations between UAE and sex, age, BMI, blood pressure, serum values of creatinine, sodium, urine volume, urine levels of calcium, citrate, urea and ammonia as well as serum calcium. No significant correlations were seen to the stone frequency (number of stone episodes), serum potassium and urine pH. In group 1 (n=741), there were 87.2% male and 12.8% female patients; in group 2 (n=1,739), the ratio was 60.6:39.4%. In the hyperuricosuric group, there were significantly more males than in the normouricosuric collective. Hyperuricosuric subjects had a higher BMI, higher blood levels of uric acid and glucose, a higher diuresis, a higher excretion of calcium, urea and ammonium, but a lower excretion of citrate than normouricosuric patients. All the other parameters did not show any significant differences. Especially the number of stone episodes was not different. We concluded that hyperuricosuria went along with many other risk factors for CaOx stone formation, but was not associated with an increased risk for recurrence. Therefore, UAE is not a prognostic marker in CaOx urolithiasis. It is unlikely that hyperuricosuria is a real risk factor for CaOx stone formation and hyperuricosuric CaOx urolithiasis is an own entity.

Metformin ameliorates calcium oxalate crystallization and stone formation by activating the Nrf2/HO-1 signaling pathway: Two birds with one stone.

Deposition of calcium oxalate (CaOx) crystals and oxidative stress-induced injury of renal tubular epithelial cell are the primary pathogenic factors of nephrolithiasis. In this study we investigated the beneficial effects of metformin hydrochloride (MH) against nephrolithiasis and explored the underlying molecular mechanism. Our results demonstrated that MH inhibited the formation of CaOx crystals and promoted the transformation of thermodynamically stable CaOx monohydrate (COM) to more unstable CaOx dihydrate (COD). MH treatment effectively ameliorated oxalate-induced oxidative injury and mitochondrial damage in renal tubular cells and reduced CaOx crystal deposition in rat kidneys. MH also attenuated oxidative stress by lowering MDA level and enhancing SOD activity in HK-2 and NRK-52E cells and in a rat model of nephrolithiasis. In both HK-2 and NRK-52E cells, COM exposure significantlylowered the expressions of HO-1 and Nrf2, which was rescued by MH treatment even in the presence of Nrf2 and HO-1 inhibitors. In rats with nephrolithiasis, MH treatment significantly rescued the down-regulation of the mRNA and protein expression of Nrf2 and HO-1 in the kidneys. These results demonstrate that MH can alleviate CaOx crystal deposition and kidney tissue injury in rats with nephrolithiasis by suppressing oxidative stress and activating the Nrf2/HO-1 signaling pathway, suggesting the potential value of MH in the treatment of nephrolithiasis.

Hormonal and molecular characterization of calcium oxalate stone formers predicting occurrence and recurrence

The purpose of the study is to investigate the role of sex hormones, androgen receptors (ARs) and miRNA/CSF-1 in occurrence and recurrence of calcium oxalate (CaOx) renal urolithiasis. In this prospective study, 74 patients with CaOx stones; stone formers group (SFG) and 40 healthy subjects; control group were compared. SFG includes both de novo and recurrent cases. Steroid sex hormone plasma assay including testosterone, free testosterone, dihydrotestosterone, estradiol, and sex hormone binding globulin was analyzed. ARs, miRNA-185-5p and CSF-1 expression were compared between the groups. SFG showed significant higher ARs and miRNA-185-5p expression (3.7 ± 1.3, 1.8 ± 0.4, respectively) than control group (1 ± 0.08 and 1 ± 0.07, respectively) (p < 0.05). However, CSF-1 expression was significantly lower in stone formers than control group (0.4 ± 0.19 vs 1 ± 0.1, respectively) (p < 0.05). No differences were detected between de novo and recurrent SFG regarding sex hormones, AR, miRNA or CSF-1 expression. Our data suggest the important role of AR, miRNA and CSF-1 signaling in human nephrolithiasis pathogenesis.

MP05-06 INDIVIDUALS' STONE COMPOSITION VARIABILITY OVER TIME: SINGLE INSTITUTION STUDY

You have accessJournal of UrologyCME1 Apr 2023MP05-06 INDIVIDUALS' STONE COMPOSITION VARIABILITY OVER TIME: SINGLE INSTITUTION STUDY Margaret A. Knoedler, Shuang Li, Ali S Antar, Stephen Y. Nakada, and Kristina L. Penniston Margaret A. KnoedlerMargaret A. Knoedler More articles by this author , Shuang LiShuang Li More articles by this author , Ali S AntarAli S Antar More articles by this author , Stephen Y. NakadaStephen Y. Nakada More articles by this author , and Kristina L. PennistonKristina L. Penniston More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003216.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Stone analysis is important for directing metabolic stone management of patients at risk for recurrent stones. In addition to results from 24 h urine collections, knowledge of stone composition serves as a pathway to diagnosis of underlying disorders. The objective of this study was to assess stone composition over time in patients with at least two composition analyses. METHODS: We retrospectively reviewed data for patients within our health system with stone composition analyses from 1997 to 2022. Patients with ≥2 analyses ≥12 months apart were identified. Stones were collected through spontaneous passage or procedures (shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy). Patients’ predominant stone compositions were defined as the component ≥60% and were otherwise considered mixed. Stones that were 100% organic material were excluded from analysis. Univariate analyses (chi-square, T test) were used to compare patients’ stone analyses. RESULTS: We reviewed 4131 stone analyses and identified 338 patients with 2 or more analyses and 76 patients who had three or more analyses. Patients were 41% female and averaged 51±14 years (min-max 18-84 years) at the time of their first stone composition. Eighty-nine (26.3%) patients had a change in their predominant stone component from the first to second stone; 26 (34.2%) had a change from the first to third stone. The mean time between the first and second stone analyses was 54 months (range 12-188, median 44 months); time between the second and third stone analyses was 76 months (range 14-258, median 61 months). A small number of patients, 3.2% of all calcium oxalate stone formers, changed from predominantly calcium oxalate in the first stone analysis to calcium phosphate in the second. This was not different (p=0.84, Fisher’s exact test) than the number whose stones changed from calcium phosphate in the first stone analysis to calcium oxalate in the second (3.8%) (Figure 1). CONCLUSIONS: Patients’ stone composition demonstrated variability in repetitive analyses. Repeating stone analyses may be an important component of long term medical stone management for individual patients. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e45 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Margaret A. Knoedler More articles by this author Shuang Li More articles by this author Ali S Antar More articles by this author Stephen Y. Nakada More articles by this author Kristina L. Penniston More articles by this author Expand All Advertisement PDF downloadLoading ...

MP05-09 IDENTIFICATION OF ABERRANT GLYCOSYLATION OF OSTEOPONTIN ON URINARY STONE FORMATION IN UROLITHIASIS PATIENTS AND RENAL STONE FORMATION RATS

You have accessJournal of UrologyCME1 Apr 2023MP05-09 IDENTIFICATION OF ABERRANT GLYCOSYLATION OF OSTEOPONTIN ON URINARY STONE FORMATION IN UROLITHIASIS PATIENTS AND RENAL STONE FORMATION RATS Go Anan, Tohru Yoneyama, Takuo Hirose, Makoto Sato, Takefumi Mori, and Chikara Ohyama Go AnanGo Anan More articles by this author , Tohru YoneyamaTohru Yoneyama More articles by this author , Takuo HiroseTakuo Hirose More articles by this author , Makoto SatoMakoto Sato More articles by this author , Takefumi MoriTakefumi Mori More articles by this author , and Chikara OhyamaChikara Ohyama More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003216.09AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Osteopontin (OPN) is one of the most important components in the calcium stone matrix. However, the relationship between glycosylation of OPN and urinary stone formation remains unknown. This study aims to identify the aberrant glycosylation profile of OPN related to urolithiasis in urolithiasis patients and renal calcium oxalate stone formation rats. METHODS: We retrospectively measured urinary glycosylated OPN normalized by urinary full-length-OPN (uFL-OPN) levels in 110 urolithiasis patients and 157 healthy volunteers. Also, we used rats with ethylene glycol-induced renal stones to evaluate the aberrant glycosylation of OPN in renal tissue. The urinary full-length-OPN levels were measured using enzyme-linked immunosorbent assay and glycosylated OPN was measured using a lectin array and lectin blotting. The assays were evaluated using the area under the receiver operating characteristics curve to discriminate stone forming urolithiasis patients. RESULTS: In the retrospective cohort, urinary Gal3C-S lectin reactive- (Gal3C-S-) OPN/uFL-OPN, was significantly higher in the stone forming urolithiasis patients than in the healthy volunteers (p<0.0001), with good discrimination (AUC, 0.953), 90% sensitivity, and 92% specificity. The Lycopersicon esculentum lectin (LEL) analysis of uFL-OPN showed that uFL-OPN in stone forming urolithiasis patients had a polyLacNAc structure that was not observed in healthy volunteers. The rats study showed that the levels of LEL-reactive OPN that had a polyLacNAc structure were increased in the renal cortex, even though total OPN levels did not increase. CONCLUSIONS: The aberrant glycosylation of OPN occurs in urine of urolithiasis patients and in renal cortex of renal stone formation rats. The aberrant glycosylation of OPN might be a marker of accelerated renal stone formation. Source of Funding: none © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e47 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Go Anan More articles by this author Tohru Yoneyama More articles by this author Takuo Hirose More articles by this author Makoto Sato More articles by this author Takefumi Mori More articles by this author Chikara Ohyama More articles by this author Expand All Advertisement PDF downloadLoading ...

Stone Formation Features in the Kidney of Residents in the South Region of Kyrgyzstan

Kidney stone disease (KSD), otherwise urolithiasis, is one of the most common and frequent diseases and occurs most often in patients of working age. With “urolithiasis” there is a metabolic disorder characterized by the presence of stones in the kidneys and urinary tract. Formation of kidney stones in residents of southern region in Kyrgyzstan has not been studied. Research objectives: determination of stone formation features in the kidney of patients in the southern region of Kyrgyzstan. Research materials and methods: a literary review of urolithiasis (KSD) of the kidneys and identification of stone formation features. Research results: kidney stone formation is a complex physical and chemical process, accompanied by growth, aggregation and retention of urinary stone in parts of tubular cells. Conclusions: formation of calcium oxalate and uric acid stones is associated with various metabolic processes in the body. Urinary calculi are formed as a result of a series of sequence of stages.

Gut microbiota-derived uremic toxins enhance calcium oxalate stone formation in vitro and in vivo

Gut microbiota-derived uremic toxins enhance calcium oxalate stone formation in vitro and in vivo

Effects of lemon-tomato juice consumption on crystal formation in the urine of patients with calcium oxalate stones: A randomized crossover clinical trial.

Dietary supplementation with citrate-containing juices may serve as an effective alternative to potassium citrate therapy for preventing calcium oxalate stone recurrence. This study was performed to evaluate whether consumption of lemon-tomato juice can decrease the tendency for stone formation in the urine of calcium oxalate stone formers. The study was conducted as a prospective interventional randomized crossover clinical trial with a repeated-measures design. Twenty-two patients with calcium oxalate stones and no metabolic abnormalities in the urine treated with lithotripsy at a tertiary care center from August 2017 to July 2018 were recruited. After a 14-hour overnight fasting, urine samples were collected after the patients consumed either milk only or milk and lemon-tomato juice. Their urine was tested for multiple parameters, including urine pH, specific gravity, calcium-creatinine ratio, and supersaturation with sodium oxalate, followed by optical density measurement via spectrophotometry. There were no significant differences in the background characteristics between the 2 groups. The optical density of the urine samples obtained after consumption of milk only was significantly higher than that after consumption of milk and lemon-tomato juice (mean = 0.131 for milk only vs. 0.053 for milk and lemon-tomato juice, p < 0.001). The urine calcium-creatinine ratio was similar between the groups (mean = 0.141 for milk only vs. 0.076 for milk and lemon-tomato juice, p = 0.019). The addition of lemon-tomato juice as a source of citrate in the diet significantly decreases the established risk factors for calcium oxalate stone formation in patients. This study was prospectively registered at CTRI under number CTRI/2017/04/008312 on April 7, 2017.

Exosomes from miR-23 Overexpressing Stromal Cells Suppress M1 Macrophage and Inhibit Calcium Oxalate Deposition in Hyperoxaluria Rat Model.

To investigate whether ADSC-derived miR-23-enriched exosomes could protect against calcium oxalate stone formation in a hyperoxaluria rat model. An ethylene glycol- (EG-) induced hyperoxaluria rat model and an in vitro model of COM-induced HK-2 cells coculturing with RAW264.7 cells were established to explore the protective mechanisms of ADSC-derived miR-23-enriched exosomes. The results showed that treatment with miR-23-enriched exosomes from ADSCs protected EG-induced hyperoxaluria rats, and cell experiments confirmed that coculturing with miR-23-enriched exosomes alleviated COM-induced cell autophagy. Overexpressed miR-23 suppressed M1 macrophage polarization by inhibiting IRF1 expression. Furthermore, the predicted binding site between the IRF1 messenger RNA 3'-untranslated region (3'-UTR) and miR-23 was confirmed by the dual-luciferase reporter assay. In conclusion, our research gave the first evidence that ADSC-derived miR-23-enriched exosomes affected the polarization of M1 macrophages by directly inhibiting IRF1 and protecting against calcium oxalate stone formation in a hyperoxaluria rat model.

ПОТЕНЦИАЛЬНЫЕ МАРКЕРЫ РЕЦИДИВИРОВАНИЯ МОЧЕКАМЕННОЙ БОЛЕЗНИ И РОЛЬ ИНГИБИТОРОВ КАМНЕОБРАЗОВАНИЯ ПРИ РЕЦИДИВИРУЮЩЕМ КАЛЬЦИЙ-ОКСАЛАТНОМ НЕФРОЛИТИАЗЕ

Nowadays urolithiasis (nephrolithiasis) is a common disease, which treatment is a serious task of health care ser- vices not only in Russia, but throughout the world. At the same time, stones of a calcium-oxalate nature are the most common stones in patients with this pathology – in about 70-80% of cases. It is also worth noting that this disease not only has rather painful manifestations, and its treatment requires large financial costs, but also has a complex multi- factorial multistage pathogenesis, understanding the mechanisms of which can provide a key to the development of the most successful therapy. Pathogenesis itself consists of several stages, such as nucleation with the formation of a crystallization center, crystal growth, aggregation and their attachment to the surface of epithelial cells.&#x0D; It is known that the human body contains various substances that affect the processes of stone formation. Thus, stone formation promoters facilitate their crystallization, and inhibitors prevent it. There is a delicate balance between promoters and inhibitors, and their imbalance is often a decisive factor in pathogenesis. By their chemical nature, inhibitors can be both inorganic and organic (proteins, glycosaminoglycans) substances. The latter are especially attracting attention, since at various concentrations they can act as both inhibitors and promoters of stone formation. To fully understand the mechanisms of calcium oxalate stone formation, this review analyzes current data on inhibitors of recurrent nephrolithiasis and their role in the pathophysiology of the process of renal stone formation.

Klotho inhibits the formation of calcium oxalate stones by regulating the Keap1-Nrf2-ARE signaling pathway.

Oxidative damage is important in calcium oxalate (CaOx) stone development but occurs via multiple pathways. Studies have shown that klotho plays an essential role in ameliorating oxidative damage. This study aims to explore the role of klotho in CaOx stones and whether the underlying mechanism is related to the regulation of Keap1-Nrf2-ARE signaling. The levels of GSH, SOD, CAT, MDA, and ROS were examined by ELISA. The klotho, Bcl-2, caspase-3, Keap1, Nrf2, HO-1, and NQO1 mRNA levels were measured by qRT‒PCR, and their protein levels were detected by Western blotting. Renal tissue apoptosis was examined by TUNEL staining, and crystal cell adherence and apoptosis in HKC cells were assessed based on the Ca2+ concentrations and by flow cytometry. The renal pathological changes and the adhesion of CaOx crystals in the kidneys were examined by hematoxylin-eosin and von Kossa staining, respectively. We constructed a CaOx kidney stone model in vitro. By regulating the klotho gene, klotho overexpression inhibited the CaOx-induced promotion of crystal cell adherence and apoptosis in HKC cells, and these effects were reversed by klotho knockdown. Moreover, our in vivo assay demonstrated that klotho overexpression alleviated glyoxylate administration-induced renal oxidative damage, renal apoptosis, and crystal deposition in the kidneys of mice, and these effects were also associated with activation of the Keap1-Nrf2-ARE pathway. Klotho protein inhibits the oxidative stress response of HKC cells through the Keap1-Nrf2-ARE signaling pathway, reduces the apoptosis of and adhesion of CaOx crystals to HKC cells, and decreases the occurrence of CaOx kidney stones. 20220304.

Inhibition of sodium-glucose cotransporter 2 suppresses renal stone formation

Background and aimsNephrolithiasis is a common renal disease with no effective medication. Sodium-glucose cotransporter-2 (SGLT2) inhibitors, an anti-diabetic agent, have diuretic and anti-inflammatory properties and could prevent nephrolithiasis. Here, we investigated the potential of SGLT2 inhibition against nephrolithiasis using large-scale epidemiological data, animal models, and cell culture experiments. MethodsThis study included the data of diabetic patients (n = 1,538,198) available in the Japanese administrative database and divided them according to SGLT2 inhibitor prescription status. For animal experiments, renal calcium oxalate stones were induced by ethylene glycol in Sprague-Dawley rats, and phlorizin, an SGLT1/2 inhibitor, was used for the treatment. The effects of SGLT2-specific inhibition for renal stone formation were assessed in SGLT2-deficient mice and a human proximal tubular cell line, HK-2. ResultsNephrolithiasis prevalence in diabetic men was significantly lower in the SGLT2 inhibitor prescription group than in the non-SGLT2 inhibitor prescription group. Phlorizin attenuated renal stone formation and downregulated the kidney injury molecule 1 (Kim1) and osteopontin (Opn) expression in rats, with unchanged water intake and urine volume. It suppressed inflammation and macrophage marker expression, suggesting the role of the SGLT2 inhibitor in reducing inflammation. SGLT2-deficient mice were resistant to glyoxylic acid-induced calcium oxalate stone formation with reduced Opn expression and renal damages. High glucose-induced upregulation of OPN and CD44 and cell surface adhesion of calcium oxalate reduced upon SGLT2-silencing in HK-2 cells. ConclusionOverall, our findings identified that SGLT2 inhibition prevents renal stone formation and may be a promising therapeutic approach against nephrolithiasis.

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

ObjectivesPolyunsaturated 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. MethodsUrine 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. ResultsmiR-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. ConclusionsPUFAs repressed renal stone-induced renal tubular damage via the miR-93-5p/Pknox1 axis.

Randall’s plaque as the origin of idiopathic calcium oxalate stone formation: an update

Randall’s plaque as the origin of idiopathic calcium oxalate stone formation: an update

Vinegar reduced renal calcium oxalate stones by regulating acetate metabolism in gut microbiota and crystal adhesion in rats.

Urolithiasis is a common urologic disease. Higher consumption of vinegar was associated with a lower risk of urolithiasis. Recent studies reported that disorder of gut microbiota and injury of the tight junction of renal tubular epithelial cells were associated with the formation of renal calcium oxalate (CaOx) stones. We aimed to explore the mechanism of vinegar reduced renal CaOx stone formation by regulating gut microbiota and the tight junction of renal tubular epithelial cells. Thirty Sprague-Dawley rats were randomly allocated to control group, model group and vinegar group. Rats in control group got 2ml/kg of sterile water by gavage. Model group rats were additionally supplied with drinking water with 1% (v/v) ethylene glycol (EG) every day. Rats in vinegar group had 1% (v/v) EG in drinking water and were gavaged with 2ml/kg of vinegar (5% acetate) every day. Vinegar reduced renal CaOx crystals and urinary oxalate. Vinegar increased the relative abundances of Ruminococcus gauvreauii, Ruminococcus torques, Ruminococcus-2, Moryella, Enterococcus, Alistipes, and Parabacteroides in the gut microbiota. Blood acetate increased in vinegar group. The renal tight junction occludin protein decreased in the model group and increased in the vinegar group. Studies in vitro verified that acetate could reverse the decline in occludin expression induced by CaOx crystals and inhibit CaOx crystal adhesion to cells. Vinegar reduced renal CaOx stones by regulating gut microbiota and increasing blood acetate to restore renal tight junction and reduce CaOx crystal adhesion.

The effects of drinking bicarbonate-rich mineral water in calcium oxalate stone formers: an open label prospective randomized controlled study in an Asian cohort.

To examine the effects of drinking bicarbonate-rich mineral water in patients with calcium oxalate stones. This was an open label prospective randomized controlled study comparing the effects of a bicarbonate-rich mineral water versus plain water on urine biochemistry in patients with calcium oxalate stones. The mineral water group were instructed to consume 1.25L of mineral water per day at meal times, and supplemented by plain water. Their total intake was up to 3L/day. Control group consumed only plain water up to 3L/day. 24h urine analyses were performed at baseline, 1, 4, 8 and 12weeks after starting protocol. 58 patients were recruited for the study. 51 patients were included in the final analysis. Baseline data were comparable between the two groups. Over the course of 12weeks, compared to patients drinking plain water, those drinking mineral water had higher overall urinary volume (difference = 644.0ml/24h, 95% CI = (206.7, 1081.3)), higher overall urinary magnesium (difference = 1.894mmol/24h, 95% CI = (1.006, 2.782)), and pH (difference = 0.477, 95% CI = (0.149, 0.804)). However, there was no difference in urinary oxalate and Tiselius index. Mineral water group had net increase of urinary citrate (at each study point compared to baseline) which was sustained until week 12, whereas plain water group showed no significant change. Drinking bicarbonate-rich mineral water in calcium oxalate stone formers increased stone inhibitors such as magnesium, citrate and moderate degree of urinary alkalinization compared to patients drinking plain water, but it did not alter Tiselius index or urinary oxalate after 12weeks.

Ferrostatin‑1 alleviates oxalate‑induced 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 ferrostatin-1 (Fer-1) 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 + Fer-1 group. Cultured human renal tubular epithelial cells (HK-2 cells) were randomly divided into three groups (n=3), namely, the control (Con), the Ox group, and the Ox + Fer-1 group. The levels of heme oxygenase 1 (HO-1), 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 E-cadherin, vimentin and α-SMA 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 HO-1 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 + Fer-1 or Ox + Fer-1 group was upregulated (P<0.05), whereas that of HO-1 and SOD2 was downregulated (P<0.05). Renal tissue damage, apoptosis of renal tubular epithelial cells and interstitial fibrosis were decreased following Fer-1 treatment (P<0.05). The ROS level was also decreased following Fer-1 treatment. Moreover, CaOx stone formation was decreased in the CaOx + Fer-1 group (P<0.05). In conclusion, Fer-1 alleviated Ox-induced renal tubular epithelial cell injury, fibrosis, and CaOx stone formation by inhibiting ferroptosis.