The Role of Diet in Kidney Stone Pathogenesis and Prevention.

Biochemical and Stone-Risk Profiles With Topiramate Treatment

Causes of Hypocitraturia in Recurrent Calcium Stone Formers: Focusing on Urinary Potassium Excretion

Gout is well known to be produced by increased uric acid level in blood. The objective of this paper is to assess the relationship between gout and calcium oxalate stone formation in the humans. 48 patients with combination of gout and calcium oxalate stone problem were included. The biochemical values of this group were compared with 38 randomly selected uric acid stone patients with gout, 43 stone patients with gout alone, 100 calcium oxalate stone patients without gout and 30 controls, making a total of 259 patients. Various biochemical parameters, namely serum calcium, phosphorus and uric acid and 24-h urine calcium, phosphorus, uric acid, oxalate, citrate and magnesium were analysed. ANOVA and Duncan's multiple-range tests were performed to assess statistical significance of the variations. The promoters of stone formation, namely serum calcium (P < 0.05), phosphorus (P < 0.05) and uric acid (P < 0.05) and urine calcium (P < 0.05), uric acid (P < 0.05) and oxalate (P < 0.05) were significantly variable in the different groups. The inhibitor citrate (P < 0.05) was also significantly variable. Multiple-range test showed that the promoters, namely serum calcium (P < 0.05) and urine uric acid (P < 0.05) were in a significantly higher range in the gouty patients, gouty uric acid stone patients and gouty calcium oxalate stone patients compared to the non-gouty patients and controls. Urine oxalate (P < 0.0001) was in the highest range in the gouty calcium oxalate or gouty uric acid stones patients. The inhibitor urine citrate (P < 0.001) was significantly lower in the gouty, gouty uric acid and gouty calcium oxalate patients. Serum uric acid was highest in the non-stone gouty patients, followed by the gouty uric acid stone formers and gouty calcium oxalate stone patients. The high values of promoters, namely uric acid and calcium in the gouty stone patients indicate the tendency for urinary stone formation in the gouty stone patients. There is probably a correlation between gout and calcium oxalate urinary stone. We presume this mechanism is achieved through the uric acid metabolism. The findings point to the summation effect of metabolic changes in development of stone disease.

Objective To evaluate dual-source dual-energy CT(DSCT) for the differentiation of urinary stone composition in vitro. Methods Ninety-seven urinary stones were obtained by endoscopic lithotripsy and scanned using dual-source dual-energy CT. The stones were divided into six groups according to infrared spectroscopy stone analysis: uric acid ( UA ) stones ( n = 10 ), cystine stones ( n = 5 ), struvite stones( n = 6), calcium oxalate ( CaOx ) stones ( n = 22 ), mixed UA stones ( n=7 ) and mixed calcium stones(n=47). Hounsfield units (HU) of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and dual energy index ( DEI ) were calculated and compared among the stone groups with one-way ANOVA. Using dual energy software to determine the composition of all stones, results were compared to infrared spectroscopy analysis. Results There were statistical differences in HU difference [(-17±13), (229±34),(309 ±45), (512 ±97), (201±64)and (530±71) HU respectively], in HU ratio (0.96±0.03, 1.34 ±0.04, 1.41 ±0.03, 1.47 ±0.03,1.30±0.07, and 1.49 ±0.03 respectively), and DEI( -0.006 ±0.004, 0.064 ±0.007, 0.080 ±0. 007, 0. 108±0.011 ,0. 055 ±0.014 and 0. 112 ±0.008 respectively ) among different stone groups(F=124. 894,407.028, 322. 864 respectively, P ＜0. 01 ). There were statistical differences in HU difference,HU ratio and DE1 between UA stones and the other groups( P ＜ 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between CaOx or mixed calcium stones and the other four groups (P＜0. 01 ). There was statistical difference in HU ratio between cystine and struvite stones ( P ＜ 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between struvite and mixed UA stones (P＜0. 05 ). Dual energy software correctly characterized 10 UA stones, 4 cystine stones, 22 CaOx stones and 6 mixed UA stones. Two struvite stones were considered to contain cystine. One cystine stone, 1 mixed UA stone, 4 struvite stones and 47 mixed calcium stones were considered to contain oxalate. Conclusions DSCT has the ability to differentiate urinary stone composition in vitro. With dual energy software, the UA, cystine and mixed UA stones can be differentiated from other types of stones. Key words: Urinary calculi; Tomography,X-ray computed

Using 24-Hour Urinalysis to Predict Stone Type

Background: Kidney stones are solid deposits that form in the urinary system, especially the kidneys, from chemical substances like salts and minerals. The pathophysiology of stone development involves aldosterone hormones and renin., as biochemical indicators of the kidney's susceptibility to different types of stones. In this study, two types of stones were used in relation to their formation in patients (calcium oxalate and uric acid stones). TNF and IL-17 were also thought to affect stone formation. Significant characteristics like smoking, BMI, and sex were examined. Objective: Assessing hormones in patients with kidney stones of both types (calcium oxalate and uric acid) and their relationship to smoking, body mass index, gender, and immunological indicators like tumor necrosis factor and interleukin-17. Methodology: This case-control study took 98 blood samples from kidney stone patients and healthy people. From May 2022 to December 2022, 68 patients with urinary tract problems, specifically kidney stones, were identified, along with 30 healthy individuals as a control group. Serum was obtained from blood. The samples were categorized as (38) calcium oxalate stone patients, (30) uric acid stone patients, and (30) healthy persons. Vital and immunological parameters were evaluated using ELISA. Results: Patients with calcium oxalate stones differed significantly from smokers (P&lt;0.05), while those with uric acid stones differed significantly from smokers in terms of body mass (P&lt;0.01). Gender index did not differ significantly across groups, but hormones (aldosterone, renin) and immune factors (TNF, IL-17) differed significantly between calcium oxalate and uric acid stones and the healthy group (P&lt;0.01). Conclusion: Hormones affected the production of calcium oxalate and uric acid stones. Aldosterone hormone release increased calcium oxalate stone development, while renin depression increased both forms of stones. Smoking had an effect on uric acid stone patients, and immune indicators like TNF and IL-17 were vital as stone formation increased their blood levels. Journal of Current and Advance Medical Research, July 2024;11(2):102-108

Background: Kidney stones are solid deposits that form in the urinary system, especially the kidneys, from chemical substances like salts and minerals. The pathophysiology of stone development involves aldosterone hormones and renin., as biochemical indicators of the kidney's susceptibility to different types of stones. In this study, two types of stones were used in relation to their formation in patients (calcium oxalate and uric acid stones). TNF and IL-17 were also thought to affect stone formation. Significant characteristics like smoking, BMI, and sex were examined. Aims of study: Assessing hormones in patients with kidney stones of both types (calcium oxalate and uric acid) and their relationship to smoking, body mass index, sex, and immunological indicators like tumor necrosis factor and interleukin-17. Methodology: This study took 98 blood samples from kidney stone patients and healthy people. Serum was obtained from blood. The samples were categorized as (38) calcium oxalate stone patients, (30) uric acid stone patients, and (30) healthy persons. Vital and immunological parameters were evaluated using ELISA. Results: Patients with calcium oxalate stones differed significantly from smokers (P&lt;0.05), while those with uric acid stones differed significantly from smokers in terms of body mass (P&lt;0.01). Gender index did not differ significantly across groups, but hormones (aldosterone, renin) and immune factors (TNF, IL-17) differed significantly between calcium oxalate and uric acid stones and the healthy group (P&lt;0.01). Conclusion: Hormones affected the production of calcium oxalate and uric acid stones. Aldosterone hormone release increased calcium oxalate stone development, while renin depression increased both forms of stones. Smoking had an effect on uric acid stone patients, and immune indicators like TNF and IL-17 were vital as stone formation increased their blood levels.

MP12-09 MATRIX PROTEIN DIFFERENCES BETWEEN URIC ACID AND CALCIUM OXALATE STONES

Temporal Changes in Kidney Stone Composition and in Risk Factors Predisposing to Stone Formation

The purpose of the present study was to compare the clinical characteristics of "pure" uric acid (UA) stone formers with that of "pure" calcium oxalate (CaOx) stone formers and to determine whether renal handling of UA, urinary pH, and urinary excretion of promoters and inhibitors of stone formation were different between the two groups. Study subjects comprised 59 patients identified by records of stone analysis: 30 of them had "pure" UA stones and 29 had "pure" CaOx nephrolithiasis. Both groups underwent full outpatient evaluation of stone risk analysis that included renal handling of UA and urinary pH. Compared to CaOx stone formers, UA stone formers were older (53.3 +/- 11.8 years vs. 44.5 +/- 10.0 years; P = 0.003); they had higher mean weight (88.6 +/- 12.5 kg vs. 78.0 +/- 11.0 kg; P = 0.001) and body mass index (29.5 +/- 4.2 kg/m(2) vs. 26.3 +/- 3.5 kg/m(2); P = 0.002) with a greater proportion of obese subjects (43.3% vs. 16.1%; P = 0.01). Patients with "pure" UA lithiasis had significantly lower UA clearance, UA fractional excretion, and UA/creatinine ratio, with significantly higher serum UA. The mean urinary pH was significantly lower in UA stone formers compared to CaOx stone formers (5.17 +/- 0.20 vs. 5.93 +/- 0.42; P < 0.0001). Patients with CaOx stones were a decade younger, having higher 24-h urinary calcium excretion (218.5 +/- 56.3 mg/24 h vs. 181.3 +/- 57.1 mg/24 h; P = 0.01) and a higher activity product index for CaOx [AP (CaOx) index]. Overweight/obesity and older age associated with low urine pH were the principal characteristic of "pure" UA stone formers. Impairment in urate excretion associated with increased serum UA was also another characteristic of UA stone formers that resembles patients with primary gout. Patients with pure CaOx stones were younger; they had a low proportion of obese subjects, a higher urinary calcium excretion, and a higher AP index for CaOx.

THE EFFICACY OF DIETARY INTERVENTION ON URINARY RISK FACTORS FOR STONE FORMATION IN RECURRENT CALCIUM OXALATE STONE PATIENTS

Kidney stones are heterogeneous but often grouped together. The potential effects of patient demographics and calendar month (season) on stone composition are not widely appreciated. The first stone submitted by patients for analysis to the Mayo Clinic Metals Laboratory during 2010 was studied (n=43,545). Stones were classified in the following order: any struvite, any cystine, any uric acid, any brushite, majority (≥50%) calcium oxalate, or majority (≥50%) hydroxyapatite. Calcium oxalate (67%) was the most common followed by hydroxyapatite (16%), uric acid (8%), struvite (3%), brushite (0.9%), and cystine (0.35%). Men accounted for more stone submissions (58%) than women. However, women submitted more stones than men between the ages of 10-19 (63%) and 20-29 (62%) years. Women submitted the majority of hydroxyapatite (65%) and struvite (65%) stones, whereas men submitted the majority of calcium oxalate (64%) and uric acid (72%) stones (P<0.001). Although calcium oxalate stones were the most common type of stone overall, hydroxyapatite stones were the second most common before age 55 years, whereas uric acid stones were the second most common after age 55 years. More calcium oxalate and uric acid stones were submitted in the summer months (July and August; P<0.001), whereas the season did not influence other stone types. It is well known that calcium oxalate stones are the most common stone type. However, age and sex have a marked influence on the type of stone formed. The higher number of stones submitted by women compared with men between the ages of 10 and 29 years old and the change in composition among the elderly favoring uric acid have not been widely appreciated. These data also suggest increases in stone risk during the summer, although this is restricted to calcium oxalate and uric acid stones.

We launched a retrospective cohort study to explore the interactions among serum uric acid (UA), urine UA, and stone types. Clinical characteristics of urolithiasis patients in Beijing Tsinghua Changgung Hospital from October 2015 to August 2017 were retrospectively collected. Participants were categorized according to the quartiles of SUA and UUA respectively. Logistic regression model was built to identify the relationship between stone composition and UA level. Cubic spline was fitted to explore the correlation between 24-h urine UA and serum UA. 718 hospitalized patients (51.1 ± 14.3years, male 63.4%) with urinary calculi were included. Higher serum UA is associated with male, alcohol use, multiple serum and urine electrolytes (e.g. potassium, chloride, calcium, phosphorus), and lower estimated glomerular filtration rate. The risk of UA stone and carbonate apatite stone was associated with serum UA while the risk of calcium oxalate (CaOx) stone and ammonium magnesium hexahydrate (AMH) was dependent on urine UA. In the unadjusted model (Model 1), higher risks of UA stones were observed in the third quartile (OR 3.26, 95% CIs 1.63-6.53, P = 0.001) and the fourth quartile (OR 3.55, 95% CIs 1.78-7.08, P < 0.001) of serum UA compared with the first quartile. The risks of carbonate apatite stone were lowered in the third (OR 0.48, 95% CIs 0.31-0.73, P = 0.001) and fourth quartile (OR 0.40, 95% CIs 0.42-0.98, P = 0.042) of serum UA. The risk of CaOx stone was increased in the fourth quartile (OR 2.14, 95% CIs 1.15-3.99, P = 0.017) while the risk of AMH stone was decreased in the third (OR 0.46, 95% CIs 0.22-0.94, P = 0.034) and fourth quartile (OR 0.35, 95% CIs 0.16-0.78, P = 0.009) of urine UA. The elevated risks of UA stones in high levels of serum UA were demonstrated in the adjusted model (Model 2). An M-shaped association was found between serum UA and urine UA in our population. Serum UA and urine UA might cast different impact on urinary calculus composition. Proper control of the parameters should be considered based on different predisposing factors in individual patients.

Background: Low urine pH and volume are established risk factors for uric acid (UA) stone disease (UASD). Renal tubular epithelial cells exposed to an acidic pH and/or UA crystals can shed extracellular vesicles (EVs) into the tubular fluid, and these EVs may be a pathogenic biomarker of UASD. Methods: Urinary EVs bearing UA transporters (SLC2A9, SLC17A3, SLC22A12, SLC5A8, ABCG2, and ZNF365) were quantified in urine from UA stone formers (UASFs), calcium stone formers (CSFs), and age-/sex-matched non-stone formers (NSFs) using a standardized and published method of digital flow cytometry. Results: Urinary pH was lower (p < 0.05) and serum and urinary UA were greater (p < 0.05) in UASFs compared with NSFs. Urinary EVs carrying SLC17A3 and SLC5A8 were lower (p < 0.05) in UASFs compared with NSFs. Urinary EVs bearing SLC2A9, SLC22A12, SLC5A8, ABCG2, and ZNF365 were lower (p < 0.05) in CSFs than UASFs, while excretion of SLC17A3-bearing EVs did not differ between groups. Conclusion: EVs bearing specific UA transporters might contribute to the pathogenesis of UASD and represent non-invasive pathogenic biomarkers for calcium and UA stone risk.

Objective To explore the risk factors of urinary stone formation in primary gout patients by urinary chemical, serum and urinary biochemical features analysis. Methods All the patients diagnosed as primary gout at Peking University First Hospital from 2009 to 2015 were included in the study. All patients were diagnosed with or without urolithiasis by ultrasound or computed tomography. Their clinical features, baseline urinary metabolic panels and stone composition were analyzed and compared between the two group of patients. Moreover, the risk factors of uric acid stone formation were determined by comparing different composition of stone formation group. Analysis of variance, t-test, chi-square test, spearman's test and logistic regression were used for statistical analysis. Results One hundred and forty-four male gout patients were enrolled in the study among these patients, 48 were with urolithiasis and 96 patients were without urolithiasis. Most (136, 94.4%) patients were under excretion of uric acid. Among 48 gout patients with uric acid urolithiasis, 30(62.5%) patients who had pure uric acid stones, and 18(37.5%) had stones composed of mixed uric acid and oxalic acid.Compared with mixed stone group, the mean age was significantly lower in pure uric acid stone group [(46±13) years vs (60±15) years, t=4.1, P<0.05]; and disease duration was shorter [(42±11) months vs (71±22) months, t=-0.2, P<0.01]. The 24-hour urinary uric acid were significantly higher in the uric acid stone group [(5 205±3 524) μmol/d vs (2 132±1 326) μmol/d, t=3.6, P<0.05]. Also, the mean of both Ccr and Cua were higher [(119±61) ml/min vs (75±39) ml/min, t=3.6, P<0.05; (6.3±3.6) ml/min vs (3.2±2.0) ml/min, t=1.4, P<0.05]. Urinary pH was negatively correlated with uric acid stone in primary gouty patients (r=-0.212, P<0.01); The total excretion of urinary uric acid was positively correlated with uric acid stones formation (r=0.633, P<0.05). High urinary uric acid excretion and Ccr were independent risk factors for uric acid stone formation in primary gout patients. Conclusion Urine pH is negatively correlated with uric acid stone formation. Urinary analysis of 24-hour uric acid and Ccr are risk factors for pure uric acid urolithiasis in primary gout patients. Key words: Gout; Uric acid; Urinary calculi