The microbiome of kidney stones and urine of patients with nephrolithiasis

The incidence of nephrolithiasis is rising worldwide. Although it is a multifactorial disease, lifestyle plays a major role in its etiology. Another considerable factor could be an aberrant microbiome. In our observational single-center study, we aimed to investigate the composition of bacteria in kidney stones and urine focusing on patients with features of metabolic syndrome. Catheterized urine and kidney stones were collected prospectively from 100 consecutive patients undergoing endoscopic nephrolithotomy between 2020 and 2021 at our clinic. Microbiome composition was analyzed via 16S rRNA gene amplicon sequencing. Detection of bacteria was successful in 24% of the analyzed kidney stones. These patients had a prolonged length of stay compared to patients without verifiable bacteria in their stones (2.9 vs 1.5 days). Patients with features of metabolic syndrome were characterized by kidney stones colonized with classical gastrointestinal bacteria and displayed a significant enrichment of Enterococcaceae and Enterobacteriaceae. Stones of patients without features of metabolic syndrome characterized by Ureaplasma and Staphylococcaceae. Patients with bacteria in their kidney stones exhibit a longer length of stay, possibly due to more complex care. Patients presenting with features of metabolic syndrome displayed a distinct stone microbiome compared to metabolically fit patients. Understanding the role of bacteria in stone formation could enable targeted therapy, prevention of post-operative complications and new therapeutic strategies.

Glycine suppresses kidney calcium oxalate crystal depositions via regulating urinary excretions of oxalate and citrate

An abnormal urine composition is a key reason for kidney stone formation, but little is known about the roles of small metabolites in the urine during kidney stone formation. Here, we found urine glycine in patients with kidney calcium oxalate (CaOx) stone was significantly lower than that in healthy people via 1 H NMR spectra detection, and investigated the role and underlying mechanism of glycine in the regulation of CaOx stone formation. Our results showed that glycine could significantly attenuate ethylene glycol-induced CaOx crystal depositions in rat kidney via decreasing urine oxalate and increasing urine citrate. Mechanism studies revealed that glycine could decrease urine oxalate through downregulating Slc26a6 expression, whereas increase urine citrate via inhibiting Nadc1 expression. Moreover, glycine decreased the protein expression of both Slc26a6 and Nadc1 via increasing the expression of miRNA-411-3p, which directly bound to the 3'-untranslated regions of Slc26a6 and Nadc1 messenger RNAs, in vitro and in vivo. Together, our results revealed a novel role of glycine in the regulation of kidney CaOx crystal formation and provided a potential target for the treatment of kidney CaOx stone.

Effect of dietary treatment and fluid intake on the prevention of recurrent calcium stones and changes in urine composition: A meta-analysis and systematic review

To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) for investigating the effect of dietary treatment and fluid intake on the prevention of recurrent calcium stones and changes in urine composition. PubMed, Web of Science, Embase, EBSCO, and Cochrane Library databases (updated November 2020) were searched for studies with the following keywords: diet, fluid, recurrent, prevention, randomized controlled trials, and nephrolithiasis. The search strategy and study selection process was conducted by following the PRISMA statement. Six RCTs were identified for satisfying the inclusion criteria and enrolled in this meta-analysis. Our result showed that low protein with or without high fiber diet intervention does not decrease the recurrence of stone upon comparing with control groups (RR = 2.32, 95% CI = 0.42–12.85; P = 0.34) with significant heterogeneity among the studies (I² = 81%, P = 0.02). But normal-calcium, low protein, low-salt diet had recurrences did reduced the recurrence compared to normal-calcium diet. And the fluid intake has a positive effect on prevention of recurrent stone formation (RR = 0.39, 95% CI = 0.19–0.80; P = 0.01) with insignificant heterogeneity among the studies (I² = 9%, P = 0.30). The different components of urine at baseline were reported in four studies. Upon reviewing the low protein with or without high fiber dietary therapy groups, it was found that there were no obvious changes in the 24-hour urine sodium, calcium, citrate, urea, and sulfate. In conclusion, our study shows that the only low protein with or without fiber does not affect recurrence, but low Na, normal Ca diet has a marked effect on reducing recurrence of calcium stone. And fluid intake shows a significant reduction in the recurrence of calcium stone.

Proton-pump inhibitors associated with decreased urinary citrate excretion

INTRODUCTION

Proton-pump inhibitors (PPIs) may increase the risk of kidney stone formation, but the mechanism has not been elucidated. There is a paucity of literature evaluating the effects of PPIs on urinary metabolites and urine pH.

METHODS

We performed a retrospective review of nephrolithiasis patients treated at our institution and compared patients who were taking PPIs to those who were not at the time of their 24-h urine collections. Hierarchical multivariate linear regression was used to evaluate the independent relationship between PPI use and urinary mineral composition.

RESULTS

We identified 301 consecutive patients, 88 (29%) of whom were taking PPIs at the time of their 24-h urine collections. Patients taking PPIs were older and more likely to have medical comorbidities associated with metabolic syndrome such as hypertension, diabetes, and dyslipidemia (p < 0.01). Controlling for these factors, patients taking PPIs were found to have 12% lower 24-h urine citrate excretion (β =  - 0.12, ΔF = 4.24, p = 0.04). There were no other differences in urinary mineral composition between the groups.

CONCLUSION

Our findings suggest that patients who take PPIs regularly may be at risk for decreased urinary citrate excretion. The consequent decrease in urinary citrate may become clinically significant for patients with other predisposing factors for hypocitraturia.

Hypomagnesuria is Associated With Nephrolithiasis in Patients With Asymptomatic Primary Hyperparathyroidism

CONTEXT

The pathogenesis of nephrolithiasis in primary hyperparathyroidism (PHPT) remains to be elucidated. The latest guidelines suggest parathyroidectomy in patients with asymptomatic PHPT with hypercalciuria (> 400 mg/d) and increased stone risk profile.

OBJECTIVE

The objective of this work is to evaluate the association of urinary stone risk factors and nephrolithiasis in patients with asymptomatic sporadic PHPT and its clinical relevance.

DESIGN

A total of 157 consecutive patients with sporadic asymptomatic PHPT were evaluated by measurement of serum and 24-hour urinary parameters and kidney ultrasound.

RESULTS

Urinary parameters were tested in the univariate analysis as continuous and categorical variables. Only hypercalciuria and hypomagnesuria were significantly associated with nephrolithiasis in the univariate and multivariate analysis adjusted for age, sex, body mass index, estimated glomerular filtration rate, parathyroid hormone, 25-hydroxyvitamin D, serum calcium, and urine volume (odds ratio, OR 2.14 [1.10-4.56]; P = .04; OR 3.06 [1.26-7.43]; P = .013, respectively). Hypomagnesuria remained associated with nephrolithiasis in the multivariate analysis (OR 6.09 [1.57-23.5], P = .009) even when the analysis was limited to patients without concomitant hypercalciuria. The urinary calcium/magnesium (Ca/Mg) ratio was also associated with nephrolithiasis (univariate OR 1.62 [1.27-2.08]; P = .001 and multivariate analysis OR 1.74 [1.25-2.42], P = .001). Hypomagnesuria and urinary Ca/Mg ratio had a better, but rather low, positive predictive value compared with hypercalciuria.

CONCLUSIONS

Hypomagnesuria and urinary Ca/Mg ratio are each associated with silent nephrolithiasis and have potential clinical utility as risk factors, besides hypercalciuria, for kidney stones in asymptomatic PHPT patients. The other urinary indices that have been commonly thought to be associated with kidney stones in PHPT are not supported by our results.

Dietary vinegar prevents kidney stone recurrence via epigenetic regulations

BACKGROUND

Epidemiological evidence of over 9000 people suggests that daily intake of vinegar whose principal bioactive component is acetic acid is associated with a reduced risk of nephrolithiasis. The underlying mechanism, however, remains largely unknown.

METHODS

We examined the in vitro and in vivo anti-nephrolithiasis effects of vinegar and acetate. A randomized study was performed to confirm the effects of vinegar in humans.

FINDINGS

We found individuals with daily consumption of vinegar compared to those without have a higher citrate and a lower calcium excretion in urine, two critical molecules for calcium oxalate (CaOx) kidney stone in humans. We observed that oral administration of vinegar or 5% acetate increased citrate and reduced calcium in urinary excretion, and finally suppressed renal CaOx crystal formation in a rat model. Mechanism dissection suggested that acetate enhanced acetylation of Histone H3 in renal tubular cells and promoted expression of microRNAs-130a-3p, -148b-3p and -374b-5p by increasing H3K9, H3K27 acetylation at their promoter regions. These miRNAs can suppress the expression of Nadc1 and Cldn14, thus enhancing urinary citrate excretion and reducing urinary calcium excretion. Significantly these mechanistic findings were confirmed in human kidney tissues, suggesting similar mechanistic relationships exist in humans. Results from a pilot clinical study indicated that daily intake of vinegar reduced stone recurrence, increased citrate and reduced calcium in urinary excretion in CaOx stone formers without adverse side effects.

INTERPRETATION

Vinegar prevents renal CaOx crystal formation through influencing urinary citrate and calcium excretion via epigenetic regulations. Vinegar consumption is a promising strategy to prevent CaOx nephrolithiasis occurrence and recurrence. FUND: National Natural Science Foundations of China and National Natural Science Foundation of Guangdong Province.

Prevalence of low molecular weight proteinuria and Dent disease 1 CLCN5 mutations in proteinuric cohorts

BACKGROUND

Dent disease type 1 (DD1) is a rare X-linked disorder caused mainly by CLCN5 mutations. Patients may present with nephrotic-range proteinuria leading to erroneous diagnosis of focal segmental glomerulosclerosis (FSGS) and unnecessary immunosuppressive treatments.

METHODS

The following cohorts were screened for CLCN5 mutations: Chronic Kidney Disease in Children (CKiD; n = 112); Multicenter FSGS-Clinical Trial (FSGS-CT) (n = 96), and Novel Therapies for Resistant FSGS Trial (FONT) (n = 30). Urinary α₁-microglobulin (α₁M), albumin (A), total protein (TP), and creatinine (Cr) were assessed from CKiD subjects (n = 104); DD1 patients (n = 14); and DD1 carriers (DC; n = 8). TP/Cr, α₁M/Cr, α₁M/TP, and A/TP from the CKiD cohort were compared with DD1 and DC.

RESULTS

No CLCN5 mutations were detected. TP/Cr was lower in DC and CKiD with tubulointerstitial disease than in DD1 and CKiD with glomerular disease (p < 0.002). α₁M/Cr was higher in DD1 than in CKiD and DC (p < 0.001). A/TP was lower in DD1, DC, and CKiD with tubulointerstitial disease and higher in CKiD with glomerular disease (p < 0.001). Thresholds for A/TP of ≤ 0.21 and α₁M/Cr of ≥ 120 mg/g (> 13.6 mg/mmol) creatinine were good screens for Dent disease.

CONCLUSIONS

CLCN5 mutations were not seen in screened CKiD/FSGS cohorts. In our study, a cutoff of TP/Cr > 600 mg/g (> 68 mg/mmol) and A/TP of < 0.3 had a high sensitivity and specificity to distinguish DD1 from both CKiD glomerular and tubulointerstitial cohorts. α₁M/Cr ≥ 120 mg/g (> 13.6 mg/mmol) had the highest sensitivity and specificity when differentiating DD1 and studied CKiD populations.

Net Acid Excretion and Urinary Organic Anions in Idiopathic Uric Acid Nephrolithiasis

BACKGROUND AND OBJECTIVES

Idiopathic uric acid nephrolithiasis, which is closely associated with obesity and the metabolic syndrome, is increasing in prevalence. Unduly acidic urine pH, the quintessential pathophysiologic feature of this disease, is in part explained by inadequate excretion of the principal urinary buffer ammonium. The role of net acid excretion in the pathogenesis of uric acid nephrolithiasis is incompletely understood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We compared acid-base parameters of patients with idiopathic uric acid nephrolithiasis with matched control subjects under controlled diets in an inpatient metabolic unit. Measurements included fasting blood and 24-hour urine chemistries and 24-hour urine metabolomic analysis. Comparisons between groups included analysis of covariance models controlling for urine pH or body mass index.

RESULTS

Subjects with idiopathic uric acid nephrolithiasis had lower urine pH (5.5 versus 5.9; P<0.001) and higher net acid excretion (60 versus 43 mEq/24 h; P<0.001), with the excess H+ carried by nonammonium buffers. In all subjects, there was a positive relationship of net acid excretion with higher body mass index in spite of strictly controlled equivalent dietary acid intake. This relationship was most evident among control subjects (r=0.36; P=0.03). It was attenuated in patients with idiopathic uric acid nephrolithiasis whose net acid excretion remained fixedly high and ammonium excretion remained low relative to net acid excretion, resulting in low urine pH over a wide body mass index range. Urinary metabolomics was performed to attempt to identify excess organic acids presented to the kidney in idiopathic uric acid nephrolithiasis. Among the tricarboxylic acid cycle intermediates and amino acid and lipid metabolites analyzed, 26 organic anions with acid dissociation constants values in the range of urine pH showed greater protonation. However, protons carried by the identified organic acids did not entirely account for the higher titratable acidity seen in idiopathic uric acid nephrolithiasis.

CONCLUSIONS

Higher acid load to the kidney, resulting in higher urinary net acid excretion, is an important factor in the pathogenesis of idiopathic uric acid nephrolithiasis.

[Therapeutic compliance in patients with renal lithiasis and biochemical risk factors.]

OBJECTIVE

To evaluate patient compliance with treatment for urinary lithiasis and to detect differences in adherence, causes of this behavior and associated factors.

METHODS

We performed a retrospective study of 93 patients with positive urinary metabolic study (UMS) for lithogenic pathology, diagnosed between 2013 and 2015, gathering data from the digital medical records and a structured telephonic questionnaire in 75 of them. Results were analyzed using the X2 test.

RESULTS

68% of the patients were males. Median age 42.92 (12.17) years. Mean follow up was 2.65 years. Most frequent metabolic alterations were: Hyperoxaluria (42.7%), Hypercalciuria (33.3%) and hipocitraturia (30.7%). Most frequently prescribed drugs: Potassium citrate (70.7%), Thiazide diuretics (26.7%) and calcium supplements (15.1). 84.2% of the patients did not know their UMS and 29.8% did not know the treatment prescribed. 41.9% followed the doses prescribed less than 50% of the times. Dietetic treatment was abandoned by 65% of the patients and pharmacological treatment by 43.5%, mainly due to laziness (62.9% vs 46.2%). 72.6% of the compliant patients experienced improvement. We find a significant relationship between academic level and diagnosis knowledge (p=0.022) and treatment (p=0.036). There were no differences in compliance depending on the number of drugs taken.

CONCLUSIONS

Despite urine metabolic study being well valued and treatment well tolerated therapeutic compliance is very low. Most patients would repeat or restart the treatment prescribed in case of recurrence. Diagnostic and therapeutic information provided was not understood.

Can urine osteopontin levels, which may be correlated with nutrition intake and body composition, be used as a new biomarker in the diagnosis of nephrolithiasis?

BACKGROUND AND AIM

The nephrolithiasis has a multifactorial etiology resulting from the interaction of metabolic, genetic and environmental factors. Parameters such as nutrition and urinary osteopontin (OPN) level may affect kidney stone formation. The purpose of this study is to evaluate the correlation between urinary OPN level and kidney stone formation and effect of nutrition on OPN level in nephrolithiasis.

MATERIALS AND METHODS

This study was conducted on 88 volunteers including 44 healthy individuals and 44 patients diagnosed with nephrolithiasis and aging between 20 and 65 years. Some serum parameters and urinary OPN levels of the individuals were analyzed. Several anthropometric measurements of the individuals were taken and calculated their body mass index. Additionally, 24-hour dietary recall and water intakes were recorded and the participants completed food-frequency questionnaire for the evaluation of their nutritional status.

RESULTS

Urinary OPN (ng/mL) levels of patients were lower than that of control group (p<0.05). Dietary energy, carbohydrate, poly-unsaturated fatty acid (PUFA) and n-6 fatty acids intakes and urinary OPN levels of male patients were positively correlated (p<0.05). Additionally, there was a negative correlation between their urinary OPN (ng/mL) and serum creatinine (mg/dL) levels of female patients (p<0.05). Body weight, waist circumference, hip circumference and body muscle mass values of healthy males were positively correlated with their urinary OPN levels (p<0.05).

CONCLUSIONS

Results of the study showed that low urinary OPN levels were correlated with increased kidney stone risk, and dietary habits can affect urinary OPN level.

[Effects of oral hypoglycemic drugs on lithogenic properties of urine in nephrolithiasis patients with concurrent type 2 diabetes]

AIM

To investigate the effects of oral hypoglycemic drugs on the lithogenic properties of urine in nephrolithiasis patients with concurrent type 2 diabetes.

MATERIALS AND METHODS

The study comprised 376 patients with recurrent nephrolithiasis and compensated type II diabetes mellitus who attended the N.A. Lopatkin Scientific Research Institute of Urology and Interventional Radiology - branch of the NMRRC of Minzdrav of Russia and D.D. Pletnev City Clinical Hospital, Moscow Health Department in 2012-2017. Patients were divided into five groups according to the administered oral hypoglycemic agent: metformin, glibenclamide, pioglitazone, canagliflozin, vildagliptin. The control group consisted of patients receiving insulin therapy.

RESULTS

Metformin tended to acidify urine, thus producing a negative effect on urate nephrolithiasis, which is the most prevalent form of nephrolithiasis among patients with type II diabetes. Glibenclamide, on the contrary, alkalized the urine, but urine pH did not go beyond the ranges of normal values. Pioglitazone increased urine density with a simultaneous tendency to decrease diuresis, which is bad for any form of nephrolithiasis. Empagliflozin increased diuresis due to drug-induced glucosuria and also increased renal excretion of uric acid salts. However, at normal urine pH values, the uricosuric effect of the drug did not lead to a significantly increased risk of urate stone formation. Vildagliptin did not have a significant effect on urine output, urine pH, and renal salt excretion.

CONCLUSION

Drug therapy for type II diabetes significantly affects the properties of urine in patients with nephrolithiasis, and it should be taken into account in the metaphylaxis of nephrolithiasis.

Study of Urine Composition of Patients With Recurrent Nephrolithiasis in Lorestan, Iran

INTRODUCTION

Nephrolithiasis is one of the most common urinary tract diseases. After the first episode of urinary calculus, the risk of recurrence is nearly 40% to 50% at 5 years. Nephrolithiasis is a systemic disease that is associated with some metabolic disorders. This study aimed to provide a picture of the frequency of metabolic abnormalities in patients with nephrolithiasis from west part of Iran.

MATERIALS AND METHODS

Patients with recurrent urinary tract calculi referred to the Nephrology-Urology Clinics in Khorramabad city were recruited. After collection of demographic data of all the patients, 24-hour urine and blood samples were taken to measure biochemical factors.

RESULTS

Of the 232 participants, 125 were males and 107 were females. Hyperoxaluria was seen in 93 (40.1%) of the participants, hypercalciuria in 55 (23.7%), hypocitraturia in 58 (25%), and hyperuricosuria in 33 (14.9%). Hyperoxaluria in the males was significantly more frequent than in the female patients. There were no significant differences between the two groups in other urinary metabolic disorders.

CONCLUSIONS

Patients with nephrolithiasis from Lorestan province may have metabolic characteristics varying from those of regions; ethnicity may be a possible reason. Variation of dietary regimens, such as the amount of meat or vegetable in the diet that can change oxalate, calcium, or citrate of urine, might have influenced the results. Time of sampling is another factor. Population-specific studies are helpful to health care providers for preventive planning for nephrolithiasis.

Dietary cation-anion difference may explain why ammonium urate nephrolithiasis occurs more frequently in common bottlenose dolphins () under human care than in free-ranging common bottlenose dolphins

Ammonium urate nephrolithiasis frequently develops in common bottlenose dolphins () managed under human care but is rare in free-ranging common bottlenose dolphins. In other species, the dietary cation-anion difference (DCAD) can affect ammonium urate urolith formation by increasing proton excretion as ammonium ions. Therefore, differences in diet between the 2 dolphin populations could affect urolith formation, but the DCAD of most species consumed by free-ranging and managed dolphins is unknown. To compare the nutrient composition of diets consumed by free-ranging and managed bottlenose dolphins, samples ( = 5) of the 8 species of fish commonly consumed by free-ranging bottlenose dolphins in Sarasota Bay, FL, and the 7 species of fish and squid commonly fed to managed bottlenose dolphins were analyzed for nutrient content. Metabolizable energy was calculated using Atwater factors; the DCAD was calculated using 4 equations commonly used in people and animals that use different absorption coefficients. The nutrient composition of individual species was used to predict the DCAD of 2 model diets typically fed to managed common bottlenose dolphins and a model diet typically consumed by common bottlenose dolphins in Sarasota Bay. To mimic differences in postmortem handling of fish for the 2 populations of bottlenose dolphins, "free-ranging" samples were immediately frozen at -80°C and minimally thawed before analysis, whereas "managed" samples were frozen for 6 to 9 mo at -18°C and completely thawed. "Free-ranging" species contained more Ca and P and less Na and Cl than "managed" fish and squid species. As a consequence, the DCAD of both model managed dolphin diets obtained using 3 of the 4 equations was much more negative than the DCAD of the model free-ranging bottlenose dolphin diet ( < 0.05). The results imply that managed bottlenose dolphins must excrete more protons in urine than free-ranging bottlenose dolphins, which will promote nephrolith formation. The nutrient composition of the free-ranging bottlenose dolphin diet, determined for the first time here, can be used as a guide for feeding managed bottlenose dolphins, but research in vivo is warranted to determine whether adding more cations to the diet will prevent urolith formation in managed dolphins.

Metabolic syndrome contributes to renal injury mediated by hyperoxaluria in a murine model of nephrolithiasis

Metabolic syndrome (MS) individuals have a higher risk of developing chronic kidney disease through unclear pathogenic mechanisms. MS has been also related with higher nephrolithiasis prevalence. To establish the influence of MS on renal function, we designed a murine model of combined metabolic syndrome and hyperoxaluria. Four groups of male Sprague-Dawley rats were established: (1) control group (n = 10) fed with standard chow; (2) stone former group (SF) (n = 10) fed with standard chow plus 0.75% ethylene glycol administered in the drinking water; (3) metabolic syndrome group (MS) (n = 10), fed with 60% fructose diet; (4) metabolic syndrome + stone former group (MS + SF) (n = 10), 60% fructose diet and 0.75% EG in the drinking water. MS group showed a significant injury to renal function when hyperoxaluria was induced. It was demonstrated by a significant decrease of creatinine clearance (p < 0.001), with higher tubular damage (34.3%, CI 95% 23.9-44.7, p < 0.001), produced by deposition of crystals, and increased tubular synthesis of osteopontin as a response to tubular damage. Induction of hyperoxaluria in rats with MS causes severe morphological alterations with a significant impairment of renal function. This impairment is not produced in rats without MS. Therefore, this model can be useful for the study of the influence of MS in stone formation.

Co-Occurrence of Asthma and Nephrolithiasis in Children

It has been proposed that epithelial dysfunction and inflammation may predispose patients to kidney stone formation. Asthma is another chronic condition related to epithelial dysfunction and inflammation. We hypothesized that pediatric patients with asthma would have an increased prevalence of nephrolithiasis. Furthermore, we investigated if asthma patients with nephrolithiasis have clinical characteristics and urine profiles that point to mechanisms of stone formation. We evaluated 865 pediatric patients who had a diagnosis of nephrolithiasis. Clinical/demographic data and 24 hour urine samples were compared between asthma + stone (n = 142) and stone only patients. Data from asthmatics without stone were also available for evaluation of medication differences among asthma + stone and asthma only patients. The prevalence of nephrolithiasis in the pediatric population at our institution was 0.08% vs. 0.31% in our pediatric asthmatic population. The prevalence of asthma in our pediatric population was 6.8% vs. 26.7% in our pediatric stone patients. Asthma + stone patients were more likely to be on a combination inhaled corticosteroid + long acting beta agonist inhaler as compared to age/gender/BMI matched asthma patients without stone (29.7% vs. 13.7%, p = 0.0012). 259 kidney stone patients had 24 hour urine samples for comparison. There was no difference in 24 hour urine profiles between asthma + stone and stone only patients. Children with asthma have a 4-fold greater prevalence of kidney stones than the general pediatric population. Similarly, children with kidney stones have a 4-fold greater prevalence of asthma. This correlation may suggest a mechanistic link between asthma and nephrolithiasis. Further investigation is needed to elucidate the pathophysiologic origin of this relationship.

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement

BACKGROUND

Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research.

DESIGN

A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved.

RESULTS

Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients.

CONCLUSIONS

This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.

Evidence for epistatic interaction between VDR and SLC13A2 genes in the pathogenesis of hypocitraturia in recurrent calcium oxalate stone formers

BACKGROUND

Genetic factors play a key role in the pathogenesis of hypocitraturia, a common risk factor for nephrolithiasis. The Na⁺-dicarboxylate cotransporter NaDC1, encoded by the sodium-dicarboxylate cotransporter (SLC13A2) gene, is a major determinant of urinary citrate excretion and its biological functions are regulated also by the vitamin D/Vitamin D receptor (VDR) biological system. The aim of this case-control study was to evaluate the possible epistatic interaction between VDR ^rs731236and SLC13A2 ^rs11567842 allelic variants in the pathogenesis of hypocitraturia.

METHODS

Recurrent calcium-oxalate stone formers (SF) with or without hypocitraturia and healthy controls (C) were genotyped. Gene-gene interactions were estimated by the 1.0 software package of multifactor dimensionality reduction (MDR).

RESULTS

The prevalence of VDR ^TT and SLC13A2 ^GG genotypes was higher in hypocitraturic SF compared to C (odds ratio [OR] 3.24, 95 % confidence interval [CI] 1.38-7.60 for VDR ^TT vs. VDR ^tt and OR 4.06, 95 % CI 1.75-9.42 for SLC13A2 ^GG vs. SLC13A2 ^AA ). MDR analysis indicated a significant interaction between VDR ^TT and SLC13A2 ^GG in hypocitraturic SF compared to C [OR 3.81 (2.11-6.88)]. These data are compatible with an epistatic interaction between the VDR ^TT and SLC13A2 ^GG genotypes with a significant impact on the magnitude of the effect (suppressive effect).

CONCLUSIONS

These results point to an epistatic interaction between the VDR and the SLC13A2 alleles in the pathogenesis of idiopathic hypocitraturia in calcium-oxalate SF.

[Modern diagnostic and management aspects of citrate therapy for uric acid nephrolithiasis]

INTRODUCTION

Iso-aciduria - long-term existence of urine pH within a narrow range (pH <0.8-1.2 units.) - activates certain enzymes for which these pH levels are favorable. Then, this activation induces precipitation of crystals corresponding to these enzymes.

OBJECTIVE

To enable citrate therapy without a risk of altering the stone chemical composition and to identify indicators reflecting the degree of metabolic disorders in patients with uric acid nephrolithiasis.

MATERIAL AND METHODS

Citrate therapy was provided with a mixture comprising "Potassium citrate monohydrate" and "Tri-sodium citrate di-hydrate" in a ratio of 2: 1. The study group included 64 patients, who had ultrasound-detected calyx stones and hyperechoic inclusions from 2 to 4 mm without acoustic shadow, located in the papillary region of the renal pyramids. Statistical analysis was performed by cross tabulations (pairing).

RESULTS

The results of the statistical analysis have proven the legitimacy and feasibility of the proposed method of classifying patients into homogeneous groups according to the disease severity.

CONCLUSION

Long-term citrate therapy should be carried out in such a way as to achieve maximum range of urine pH (from 5.4 to 7.8 units), which will allow to avoid deposition of other crystals upon the existing stone and identify indicators reflecting the degree of metabolic disorders in patients with uric acid nephrolithiasis.

CONCLUSION

Long-term citrate therapy should be carried out in such a way as to achieve maximum range of urine pH (from 5.4 to 7.8 units), thus avoiding deposition of other crystals upon the existing stone.

[Nutritional management of kidney diseases in children]

The prevalence of various kidney diseases in children remains high in recent decades. Adequate nutrition management can enhance the effectiveness of drug treatment, slow the frequency of relapses andprevent the progression of the disease. The article is devoted to modern approaches to diet therapy in various kidney diseases in children with the defeat of tubular and glomerular appa ratus. For the first time the therapeutic diets for children with various kidney diseases are presented. Particular attention is paid to diet therapy in nephrotic syndrome (steroid-responsive and steroid-refractory). Dietary approaches with modern formulas for enteral nutrition in cases of steroid therapy complications in children with renal insufficiency (in predialysis stage and on dialysis) are described. Differentiated nutritional approaches for patients with different types of crystalluria are separately presented.

Mechanism by which shock wave lithotripsy can promote formation of human calcium phosphate stones

Human stone calcium phosphate (CaP) content correlates with higher urine CaP supersaturation (SS) and urine pH as well as with the number of shock wave lithotripsy (SWL) treatments. SWL does damage medullary collecting ducts and vasa recta, sites for urine pH regulation. We tested the hypothesis that SWL raises urine pH and therefore Cap SS, resulting in CaP nucleation and tubular plugging. The left kidney (T) of nine farm pigs was treated with SWL, and metabolic studies were performed using bilateral ureteral catheters for up to 70 days post-SWL. Some animals were given an NH4Cl load to sort out effects on urine pH of CD injury vs. increased HCO3 (-) delivery. Histopathological studies were performed at the end of the functional studies. The mean pH of the T kidneys exceeded that of the control (C) kidneys by 0.18 units in 14 experiments on 9 pigs. Increased HCO3 (-) delivery to CD is at least partly responsible for the pH difference because NH4Cl acidosis abolished it. The T kidneys excreted more Na, K, HCO3 (-), water, Ca, Mg, and Cl than C kidneys. A single nephron site that could produce losses of all of these is the thick ascending limb. Extensive injury was noted in medullary thick ascending limbs and collecting ducts. Linear bands showing nephron loss and fibrosis were found in the cortex and extended into the medulla. Thus SWL produces tubule cell injury easily observed histopathologically that leads to functional disturbances across a wide range of electrolyte metabolism including higher than control urine pH.

Preventive treatment of calcium oxalate crystal deposition with immortal flowers

ETHNOPHARMACOLOGICAL RELEVANCE

A number of medicinal plants are used for their diuretic, urolithiatic and anti-inflammatory effects on urinary system problems in Turkey and the most common traditional remedy for kidney stones is the tea of immortal flowers. The aim of this study is to evaluate the preventive effect of infusions prepared from capitulums of Helichrysum graveolens (M.Bieb.) Sweet (HG) and Helichrysum stoechas ssp. barellieri (Ten.) Nyman (HS) on formation of kidney stones.

MATERIALS AND METHOD

Sodium oxalate (Ox-70mg/kg intraperitoneally) was used to induce kidney stones on Wistar albino rats. At the same time, two different doses of the plant extracts (HG: 62.5 and 125mg/kg; HS: 78 and 156mg/kg) were dissolved in the drinking water and administered to animals for 5 days. Potassium citrate was used as positive control in the experiments. During the experiment, water intake, urine volume and body weights of the animals were recorded. At the end of the experiments, liver, kidney and body weights of the animals were determined; biochemical analysis were conducted on urine, blood and plasma samples. Histopathological changes in kidney tissues were examined and statistical analysis were evaluated.

RESULTS

HS extract showed the highest preventive effect at 156mg/kg dose (stone formation score: 1.16), whereas a number of kidney stones were maximum in sodium oxalate group (stone formation score: 2.66). Helichrysum extracts decreased urine oxalate and uric acid levels and increased citrate levels significantly. In addition, Helichrysum extracts regulated the negative changes in biochemical and hematological parameters occurred after Ox injection.

CONCLUSIONS

We conclude that Helichrysum extracts could reduce the formation and growth of kidney stones in Ox-induced urolithiasis and can be beneficial for patients with recurrent stones. In addition, this is the first study on the preventive effect of immortal flowers.

[Metabolic therapy of nephrolithiasis in two different rat models of kidney disease]

108 albino male rats were used in two experimental rat models reproducing urolithiasis for the assessment of metabolic drug medicine Remaxol nephroprotective effect upon the development of this disease. "Ethyleneglycol" model consisted of adding 1% ethylene glycol solution in drinking water for 37 days and "fructose-induced" one--of adding 10% fructose solution in drinking water for the same period. Therapy included a 10-day course of daily i.v. injections of Remaxol (14 ml/kg). Both experimental models were successful in producing urolithiasis with considerable disturbances in the structure and functioning of kidneys up to revealing microconcrement formation. The "ethyleneglycol" model proved to cause maximum changes while the "Fructose-induced" model--only moderate ones. Metabolic correction of these changes was successful in nephroprotection effectively normalizing kidney functions and the total protein concentration, eliminating hyperglycemia and reducing creatinine and urea blood plasma concentration in both rat experimental models.

Elevated levels of miR-155 in blood and urine from patients with nephrolithiasis

BACKGROUND

Both circulating and urinary miRNAs may represent a potential noninvasive molecular biomarker capable of predicting chronic kidney disease, and, in the present study, we will investigate the serum and urinary levels of miR-155 in patients with nephrolithiasis.

METHODS

Serum and urinary levels of miR-155 are quantified in 60 patients with nephrolithiasis; the result was compared to 50 healthy volunteers. Estimated glomerular filtration (eGFR) was calculated and, by simple regression analysis, the correlations of miR-155/eGFR and miR-155/CRP (C-reactive protein) levels were analyzed as well.

RESULTS

The median levels of serum and urinary levels of miR-155 are significantly higher in nephrolithiasis patients than in controls. eGFR inversely correlates with urinary level of miR-155; CRP positively correlates with urinary miR-155. Urinary level of miR-155 inversely correlates with urinary expression of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor- (TNF-) α and positively correlates with urinary expression of regulated upon activation, normal T-cell expressed, and secreted (RANTES).

CONCLUSION

Serum and urinary levels of miR-155 were significantly elevated in patients with nephrolithiasis, and the upregulation of miR-155 was correlated with decline of eGFR and elevation of CRP. Our results suggested that miR-155 might play important roles in the pathophysiology of nephrolithiasis via regulating inflammatory cytokines expression. Further study on the molecular pathogenic mechanism and larger scale of clinical trial are required.

Nephrolithiasis: molecular mechanism of renal stone formation and the critical role played by modulators

Urinary stone disease is an ailment that has afflicted human kind for many centuries. Nephrolithiasis is a significant clinical problem in everyday practice with a subsequent burden for the health system. Nephrolithiasis remains a chronic disease and our fundamental understanding of the pathogenesis of stones as well as their prevention and cure still remains rudimentary. Regardless of the fact that supersaturation of stone-forming salts in urine is essential, abundance of these salts by itself will not always result in stone formation. The pathogenesis of calcium oxalate stone formation is a multistep process and essentially includes nucleation, crystal growth, crystal aggregation, and crystal retention. Various substances in the body have an effect on one or more of the above stone-forming processes, thereby influencing a person's ability to promote or prevent stone formation. Promoters facilitate the stone formation while inhibitors prevent it. Besides low urine volume and low urine pH, high calcium, sodium, oxalate and urate are also known to promote calcium oxalate stone formation. Many inorganic (citrate, magnesium) and organic substances (nephrocalcin, urinary prothrombin fragment-1, osteopontin) are known to inhibit stone formation. This review presents a comprehensive account of the mechanism of renal stone formation and the role of inhibitors/promoters in calcium oxalate crystallisation.

An individualized weight-based goal urine volume model significantly improves expected calcium concentrations relative to a 2-L goal urine volume

Increased urinary volume decreases recurrence rates of nephrolithiasis. Current recommendations for goal volumes are not adjusted to reflect individual risk factors, such as obesity. Our intent was to develop and evaluate a goal urine volume for stone prevention based on predictive calcium modeling. Stone formers with a 24-h urine study (6/2001-9/2010) were identified. Patients with inadequate collections or non-calcium stones were excluded. Multivariate and univariate predictive models for daily calcium were evaluated and a univariate (weight) model was selected. A target calcium concentration constant (2.5 mM) was determined from current recommendations. Individualized weight-based goal urine volumes (WGUV) were calculated. Measured calcium concentration and expected calcium concentrations using a 2-L goal volume and WGUV were compared. 185 of 399 patients met inclusion criteria. Body weight was a strong predictor of calcium excretion in each model (p < 0.0001). While a 2-L goal urine volume would be expected to improve mean calcium concentrations for the cohort from 3.53 to 2.96 mM, the benefit is unequal between subsets with nearly twofold expected concentration for the highest weight quartile (3.98 vs. 2.10 mM) and higher expected concentration for males (3.35 vs. 2.59 mM). By contrast, a WGUV model improves expected concentrations for all subsets to <2.9 mM and the overall cohort to 2.50 mM. This study demonstrates a strong relationship between body weight and urinary calcium excretion in stone formers. We introduce the novel concept of individualized goal urine output using statistical modeling, which may be preferable to current recommendations.

[Citrate and renal stones]

Citrate is a powerful inhibitor of the crystallization of calcium salts. Hypocitraturia is a biochemical common alteration in calcium stone formation in adults and especially in children. The acid pH (systemic, tubular and intracellular) is the main determinant of citrate excretion in the urine. While the etiology of hypocitraturia is idiopathic in most patients with kidney stones, there are a number of causes for this abnormality including distal renal tubular acidosis, hypokalemia, diets rich in animal protein and / or diets low in alkali and certain drugs, such as acetazolamide, topiramate, ACE inhibitors and thiazides. Dietary modifications that benefit these patients include high intake of fluids and fruits, especially citrus, sodium and protein restriction, with normal calcium intake. Treatment with potassium citrate is effective in patients with primary or secondary hypocitraturia and acidification disorders, which cause unduly acidic urine pH persistently. Adverse effects are low and are referred to the gastrointestinal tract. While there are various preparations of citrate (potassium citrate, sodium citrate, potassium citrate, magnesium) in our country is available only potassium citrate powder that is useful to correct both the hypocitraturia and the low urinary pH and reduce markedly the recurrence of kidney stones.

[Estimation of renal function reserve in percutaneous nephrolithotomy of coral nephrolithiasis]

From November 2010 to December 2011, 56 patients with coral nephrolithiasis underwent percutaneous nephrolithotomy. To assess the renal function before surgery and before discharge (6 to 7 days after surgery), glomerular filtration rate (GFR) by Cockcroft-Gault equation was defined. Preoperative renal functional reserve was evaluated by method using a single oral loading of protein drugs. 46.4% of patients have decreased GFR before surgery, and before discharge the proportion of such patients was 39.3%. In 80% of patients with reduced GFR, postoperative filtering function of the kidneys in response to a protein load was increased, but did not reach the pre-operative no-load values, and in 7.5% of cases corresponded to a load indicators. Filtering function of the kidneys before discharge below baseline and load levels was observed only in 8.9% of cases. The data obtained in most cases allowed to predict GFR decline in the postoperative period in patients with coral nephrolithiasis. 87.5% of patients before surgery were characterized by the absence of renal functional reserve, but in 28.6% of patients in the postoperative period there was an increase in GFR, indicating the positive impact of endoscopic percutaneous nephrolithotomy on the functional state of the kidneys in the immediate postoperative period.

Relationship between serum vitamin D and 24-hour urine calcium in patients with nephrolithiasis

OBJECTIVE

To examine the relationship between serum 25-OH vitamin D and 24-hour urine calcium in patients with nephrolithiasis.

METHODS

A retrospective review was performed. Patients evaluated in 2 metabolic stone clinics were included for analysis. Multivariate linear regression models were adjusted for known risk factors for stone disease (age, gender, body mass index, hypertension, diabetes mellitus, gout, relevant medications, and 24-hour urine composition).

RESULTS

One-hundred sixty-nine patients were included in the study. Female to male ratio was 69:100, mean age was 50.9 years (SD 13.7), and mean body mass index was 27.4 (SD 6.4). Vitamin D deficiency (25-OH vitamin D <20 ng/mL) was present in 18.9% of patients, vitamin D insufficiency (>20, <30 ng/mL) was present in 34.9% of patients, and vitamin D was within normal limits (≥ 30 ng/mL) in 46.1% of patients. On age-adjusted and multivariate linear regression, serum 25-OH vitamin D was not related to 24-hour urine calcium (age adjusted β = -0.31 m 95% CI -1.9 to 1.3; multivariate adjusted β = 0.08, 95% CI -1.3 to 1.5).

CONCLUSION

Although 25-OH vitamin D is involved in the body's calcium homeostasis, our study does not show a relationship between serum vitamin D level and 24-hour urine calcium excretion in stone-formers. This information may have implications regarding the safety of vitamin D repletion in patients with nephrolithiasis.

Relationship between glomerular filtration rate and 24-hour urine composition in patients with nephrolithiasis

OBJECTIVE

To examine the relationship between GFR and 24-hour urine composition in patients with nephrolithiasis to understand how renal function may affect stone risk. Alterations in glomerular filtration rate (GFR) are associated with a number of physiological changes.

METHODS

A retrospective, institutional review board-approved review of patients from 2 metabolic stone clinics was performed. One-way analysis of variance and multivariate linear regression models were used to evaluate the relationship between GFR quintile and 24-hour urine composition.

RESULTS

A total of 403 patients (241 male, 162 female) with a mean age of 52.6 ± 14.2 years were included in the study. On univariate analysis, decreasing GFR by quintile was associated with significant reductions in urine calcium, citrate, supersaturation of calcium oxalate, and supersaturation of calcium phosphate (P < .05 for each). In multivariate linear regression models, decreasing GFR by quintile was associated with significant decreases in urine calcium (β = -11.2, 95% CI = -18.3 to 4.01), urine citrate (β = -32.4, 95% CI = -54.1 to 10.8), oxalate (β = -1.83, 95% CI = -2.85 to 0.81), supersaturation of calcium oxalate (β = -0.58, 95% CI = 0.84 to 0.33) and supersaturation of calcium phosphate (β = -0.09, 95% CI = 0.17 to 0.02), as well as an increase in urine magnesium (β = 3.40, 95% CI = 0.7 to 6.1).

CONCLUSION

Reduction in GFR is associated with decreased urine calcium, oxalate, and citrate, and increased urine magnesium. These findings have implications for treatment of patients with stone disease and impaired renal function.

Metabolic syndrome in obese adolescents is associated with risk for nephrolithiasis

OBJECTIVES

To examine the relationship between urinary pH and metabolic syndrome risk factors along with insulin resistance in obese adolescents, and to evaluate the relationship between other urinary stone-forming and -inhibiting markers and metabolic syndrome.

STUDY DESIGN

A total of 46 obese adolescents were enrolled. Twenty-four hour and randomly obtained urine samples were analyzed for urinary pH, promoters of stone formation (ie, uric acid, oxalate, and relative saturation ratio of calcium oxalate [RSR-CaOx]), and inhibitors of stone formation (ie, citrate and osteopontin). Other data collected included height, weight, blood pressure, and fasting lipid, insulin, and glucose levels.

RESULTS

The subjects had a mean age of 14.6±2.0 years and a mean body mass index of 36±6.3 kg/m(2). Random urine pH and the number of risk factors for metabolic syndrome were negatively correlated (r=-0.34; P=.02). RSR-CaOx was correlated with both homeostasis model assessment of insulin resistance score (r=0.38; P<.01) and number of risk factors for metabolic syndrome (r=0.47; P=.001)

CONCLUSION

Decreased urinary pH and increased RSR-CaOx are associated with risk factors for metabolic syndrome in obese adolescents.

Beware the low urine pH--the major cause of the increased prevalence of nephrolithiasis in the patient with type 2 diabetes

There is an increased prevalence of nephrolithiasis and an increase in the incidence of renal colic in patients with diabetes, obesity, hypertension and insulin resistance because of an increased frequency of uric acid crystallization. Uric acid crystallization occurs in the milieu of an acid urine and is not due to hyperuricosuria as with insulin resistance, urinary uric acid levels are generally decreased because of increased renal tubular reabsorption. However, in the presence of insulin resistance, there is decreased renal tubular generation of ammonia and increased sodium absorption leading to acidification of the urine and uric acid crystallization. The presence of a low urine pH should alert the clinician to the increased risk of nephrolithiasis particularly in the obese, diabetic or hypertensive patient. Prevention of nephrolithiasis can be achieved in susceptible individuals either by alkalizing the urine and/or by further decreasing the uric acid content of the urine with a xanthine oxidase inhibitor such as allopurinol.

Extensive characterizations of bacteria isolated from catheterized urine and stone matrices in patients with nephrolithiasis

BACKGROUND

Urinary tract infections are generally known to be associated with nephrolithiasis, particularly struvite stone, in which the most common microbe found is urea-splitting bacterium, i.e. Proteus mirabilis. However, our observation indicated that it might not be the case of stone formers in Thailand. We therefore extensively characterized microorganisms associated with all types of kidney stones.

METHODS

A total of 100 kidney stone formers (59 males and 41 females) admitted for elective percutaneous nephrolithotomy were recruited and microorganisms isolated from catheterized urine and cortex and nidus of their stones were analyzed.

RESULTS

From 100 stone formers recruited, 36 cases had a total of 45 bacterial isolates cultivated from their catheterized urine and/or stone matrices. Among these 36 cases, chemical analysis by Fourier-transformed infrared spectroscopy revealed that 8 had the previously classified 'infection-induced stones', whereas the other 28 cases had the previously classified 'metabolic stones'. Calcium oxalate (in either pure or mixed form) was the most common and found in 64 and 75% of the stone formers with and without bacterial isolates, respectively. Escherichia coli was the most common bacterium (approximately one-third of all bacterial isolates) found in urine and stone matrices (both nidus and periphery). Linear regression analysis showed significant correlation (r = 0.860, P < 0.001) between bacterial types in urine and stone matrices. Multidrug resistance was frequently found in these isolated bacteria. Moreover, urea test revealed that only 31% were urea-splitting bacteria, whereas the majority (69%) had negative urea test.

CONCLUSIONS

Our data indicate that microorganisms are associated with almost all chemical types of kidney stones and urea-splitting bacteria are not the major causative microorganisms found in urine and stone matrices of the stone formers in Thailand. These data may lead to rethinking and a new roadmap for future research regarding the role of microorganisms in kidney stone formation.

[Monocytic chemotaxic protein-1 and beta2-microglobulin: a role in estimation of renal parenchyma damage in surgical treatment of nephrolithiasis]

To estimate renal damage and intensity of tubulointerstitial fibrosis basing on the data of modern molecular markers in surgical treatment of nephrolithiasis, we examined the results of surgical treatment of 200 nephrolithiasis patients divided into 5 groups by the method of surgery. We estimated content of molecular mediators of nephrofibrosis in the urine and severity of renal dysfunction. We were the first to follow up urinary excretion of proinflammatory and profibrotic monocytic chemoattractant protein-1 (MCP-1) and low-molecular protein beta-2-microglobulin which is a reliable indicator of tubular impairment. Our study demonstrated the highest efficacy and low traumatic risk of percutaneous nephrolithotripsy. We determined diagnostic levels of the studied laboratory indices which can be used for identification of impacts on nephrofibrosis processes.

[Experimental nephrolithiasis: nephroprotective effect of calcium antagonists]

Increasing intracellular calcium ion concentration in the cytoplasm is the starting point in the activation of cell death. Regulation of these pathological processes in various organs and tissues is possible using agents from the group of calcium antagonists. This study was aimed at assessing the level of urinary excretion of two enzymes, lactate dehydrogenase (LDH, EC 1.1.1.27) and y-glutamyltransferase (GGT, EC 2.3.2.2), calcium antagonists in an experimental model of nephrolithiasis and finding ways to pharmacological protection of the kidneys. It established that the use of calcium antagonists can reduce the excretion of LDH by 20% and the excretion of GGT by more than 40%.

[Transcutaneous nephrolithotripsy in presenile and senile patients]

A total of 323 transcutaneous roentgenoendoscopic operations were made in 212 patients from January 2000 to December 2009 including 96 operations in 81 presenile and senile patients (87 and 9 operations, respectively). Transcutaneous nephrolithotripsy (TCNT) eliminated concrement from the kidney for one session in 59 (72.8%) patients. It proved to be the most sparing treatment in serious clinical situations and provided maximally complete evacuation of the concrement from the kidney. A total complication rate was 14.8%. All the complications were cured with conservative pharmacotherapy. TCNT has the same indications as open surgery, is a method of choice in presenile and senile patients with large, stag-horn and recurrent concrements of the kidney, impacted pelvicoureteral concrements, in impaired renal urodynamics and high bacteriuria. TCNT can be used as a second-line treatment in failure of extracorporeal shock-wave lithotripsy or in combination with it (sandwich-therapy) for complete concrement elimination.

[Combined treatment of patients with nephrolithiasis complicated with secondary pyelonephritis]

A total of 151 patients with nephrolithiasis participated in the study of efficacy and safety of the drug prolit cepto in conservative treatment of nephrolithiasis patients, preoperative preparation and in postoperative period after extracorporeal shock-wave lithotripsy (EC-SWL) or nephrolitholapaxy. It was found that combined treatment of nephrolithiasis complicated by secondary pyelonephritis with addition of prolit cepto raises efficacy in management of inflammation due to a positive action on microcirculation and urine bacteria. Administration of prolit cepto in nephrolithiasis patients exposed to EC-SWL or nephrolitholapaxy reduces the risk of infectious and inflammatory complications, has a nephroprotective effect and improves the course of postoperative period.

Fasting versus 24-h urine pH in the evaluation of nephrolithiasis

An abnormal urinary pH (UpH) represents an important risk factor for nephrolithiasis. In some stone formers, a fasting urine specimen is obtained instead of a 24-h urine collection for stone risk evaluation. We examined the relationship between 24-h and fasting UpH in non-stone forming individuals and stone formers with various etiologies and a wide range of urine pH to test the validity of fasting UpH. Data from 159 subjects was examined in this retrospective study. We included non-stone forming subjects and stone formers with hypercalciuria, distal renal tubular acidosis, idiopathic uric acid nephrolithiasis, or chronic diarrhea. Participants collected a 24-h urine followed by a 2-h fasting urine. For the entire cohort, a significant correlation was seen between fasting and 24-h UpH (r (2) = 0.49, p < 0.001). Fasting pH was significantly higher than 24-h UpH for the entire cohort (6.02 ± 0.63 vs. 5.89 ± 0.51; p < 0.001), and in the subgroups of non-stone formers and stone formers with hypercalciuria or distal renal tubular acidosis. Fasting UpH was >0.2 pH units different from 24-h UpH in 58% of participants. The difference between fasting and 24-h UpH did not correlate with net gastrointestinal alkali absorption or urine sulfate, suggesting that dietary factors alone cannot explain this difference in UpH. Fasting urine pH correlates moderately with 24-h urine pH in a large cohort of individuals. Significant variability between these two parameters is seen in individual patients, emphasizing the cardinal role of 24-h urine collection for evaluating UpH in nephrolithiasis.

[Effects of water drinking regimens on crystallization intensity in experimental nephrolithiasis]

We studied effects of water regimens on crystallization efficacy in experimental nephrolithiasis on 3 groups of Wistar male rats with initial experimental nephrolithiasis (ethylene glycol model). The animals were on free, limited and supernormal liquid intake regimen. For 3 weeks each 3-4 days we estimated 24-h diuresis, urine concentration of calcium, phosphate and oxalate ions. After 3 weeks we made a morphological examination of the kidneys. We found that limited drinking leads to an increase in urinary concentrations of oxalate- and phosphate ions which stimulate enhanced formation of calcium-containing concrements. More water intake considerably reduces oxalate and phosphate concentrations in the urine resulting in reduction of the number and size of calcium deposits in renal tissue. Thus, low liquid intake leads to intensification of urine oversaturation causing formation of renal concrements. Much liquid intake weakens oversaturation and reduces the number and size of calcium deposits in the kidneys.

Urinary alkalization for the treatment of uric acid nephrolithiasis

Three major conditions control the potential for uric acid stones: the quantitative excretion of uric acid, the volume of urine as it affects the urinary concentration of uric acid and the urinary pH. However, the most important factor for uric acid stone formation is acid urinary pH that is a prerequisite for uric acidic stone formation. Indeed the goal standard of urinary alkalization is to achieve a pH of 6-6.5. Administration of alkali should be titrated appropriately by pH paper to record urinary pH until a steady state is achieved. Alkali therapy such as sodium bicarbonate and potassium citrate has been advocated on the basis of established clinical experience, although potassium citrate should be preferred because it may avoid the complication of calcium salt precipitation. Recently it has been reported the clinical efficacy of therapy with potassium citrate/potassium bicarbonate for dissolution of radiolucent stones respect to control study period (only water daily intake of 1500 ml). Furthermore, mean urinary pH was significantly continuously higher during the alkali treatment study in comparison to the control study period, even though the mean of urinary volumes were similar in the two periods. In conclusion urinary alkalization with maintaining continuously high urinary pH values, could be the treatment of choice for stone dissolution and prevention of uric acid stones.

Calcium oxalate nephrolithiasis: urinary "medium size peptides"analysis using MALDI-TOF mass spectrometry

OBJECTIVE

Urinary lithiasis is one of the most common benign urological diseases. The pathogenic mechanisms of renal stone formation are complex and not clearly defined. We have studied the urinary protein composition of patients affected by calcium oxalate (CaOx) nephrolithiasis in a range of molecular weight between 1 and 5 kDa (medium size peptides). These molecules seem to have a double role in limiting the crystal adhesion to renal cells and at the same time in facilitating the degradation of crystals once internalised in cells. Their daily excretion is high, approximately 2-7 mg/die, even if studies have reported higher values. Our aim in surveying the urinary peptides was to look for qualitative difference in the medium size range, possible indication of the presence of a biomarker or any predisposing factors in patients affected by calcium oxalate nephrolithiasis.

MATERIALS AND METHODS

The urinary protein composition of 17 patients (11 male, 6 female; mean age 45 yrs +/- 14SD) affected by CaOx nephrolithiasis was assessed in comparison with 17 healthy subjects. It was performed a qualitative assay using MALDI-TOF mass spectrometry (MS) in a range of molecular weight between 1 and 5kDa (medium size peptides).

RESULTS

No differences were detected in the mass spectrums between patients and control subjects: all peaks overlapped. In addition, the values of peak intensity were comparable in both patient and control subject mass spectrums.

CONCLUSIONS

In the range of molecular weight between 1 and 5 kDa, we have not detected significant differences in the urinary composition between stone former patients and healthy subjects. Our results warrant further research in different molecular size peptides.

[Xanthinuria type I as the cause of nephrolithiasis in 17-years old girl]

Classic xanthinuria is a rare metabolic defect concerning the final reactions of purine catabolism. There are two types of the disorder: type I results from xanthine dehydrogenase (XDH) deficiency, while type II is characterized by lack of both XDH and aldehyde oxidase activity. Both types are clinically similar and are characterized by elevated xanthine concentration in body fluids that can lead to xanthine crystallisation. The most common manifestation of the disease is urolithiasis, but in most cases xanthinuria remains asymptomatic and the diagnosis is accidental. In the paper we report the first case study of xanthinuria in Poland in a child presenting with urolithiasis. 17-years old female patient was diagnosed because of recurrent urinary lithiasis and hypouricemia was detected during routine tests. Plasma and urine concentrations of oxypurines were measured by high-performance liquid chromatography (HPLC) and showed typical features of xanthinuria: hypouricemia, hypouricosuria, xanthinuria and elevated plasma xanthine. The allopurinol loading test demonstrated type I xanthinuria. The presented case report supports that first symptoms of xanthinuria can appear at any age and this disorder should be considered during diagnosing urolithiasis.

Adequacy of a single 24-hour urine collection for metabolic evaluation of recurrent nephrolithiasis

PURPOSE

There is much debate about whether 1 or 2, 24-hour urinalyses are adequate for metabolic evaluation of stone formers. We determined whether repeat 24-hour urine collection provides information similar to that of the initial 24-hour urine collection and whether repeat collection is necessary.

MATERIALS AND METHODS

We analyzed 2, 24-hour urine collections in 777 patients obtained from 2001 to 2005. Samples were collected 3 days or less apart before pharmacological intervention and analyzed elsewhere for routine stone risk profiles of urine calcium, oxalate, citrate, uric acid, sodium, potassium, magnesium, phosphorus, ammonium, chloride, urea nitrogen and creatinine.

RESULTS

No parameters showed a statistically significant difference between 24-hour urine samples 1 and 2 when mean values were compared (pairwise t test each p >0.05, range 0.06 to 0.87). Using Pearson's correlation all parameters showed positive correlation coefficients (r = 0.68 to 0.89, each p <0.0001). The mean of individual patient differences in samples 1 and 2 were compared to 0 and 6 of 12 showed no difference (p >0.05) while for the remaining 6 p value was <0.05. The percent difference was 0.5% to 4.19% for all urinary parameters.

CONCLUSIONS

One 24-hour urine sample is sufficient for metabolic evaluation of recurrent stone disease. There is no significant difference in 12 urinary parameters between 24-hour urine samples collected within 3 days of each other. This information is useful to providers and may decrease patient inconvenience and the overall cost of metabolic stone evaluation.

Hypocitraturia in common bottlenose dolphins (Tursiops truncatus): assessing a potential risk factor for urate nephrolithiasis

Numerous cases of urate nephrolithiasis in managed collections of common bottlenose dolphins (Tursiops truncatus) have been reported, but nephrolithiasis is believed to be uncommon in wild dolphins. Risk factors for urate nephrolithiasis in humans include low urinary pH and hypocitraturia. Urine samples from 94 dolphins were collected during April 2006 through June 2009 from 4 wild populations (n = 62) and 4 managed collections (n = 32). In addition, urine uric acid and pH were tested in a subset of these animals. Our null hypothesis was that wild and managed collection dolphins would have no significant differences in urinary creatinine, citrate, and uric acid concentrations and pH. Among urine samples from all 94 dolphins, the urinary levels (mean +/- SEM) for creatinine, citrate, uric acid, and pH were 139 +/- 7.6 mg/dL, 100 +/- 20 mg citrate/g creatinine, 305 +/- 32 mg uric acid/g creatinine, and 6.2 +/- 0.05, respectively. Of the 4 urinary variables, only citrate concentration varied significantly between the 2 primary study groups; compared with wild dolphins, managed collection dolphins were more likely to have undetectable levels of citrate in the urine (21.0% and 81.3%, respectively). Mean urinary citrate concentrations for managed collection and wild dolphin populations were 2 and 150 mg citrate/g creatinine, respectively. We conclude that some managed collections of dolphins, like humans, may be predisposed to urate nephrolithiasis due to the presence of hypocitraturia. Subsequent investigations can include associations between metabolic syndrome, hypocitraturia, and urate nephrolithiasis in humans and dolphins; and the impact of varying levels of seawater ingestion on citrate excretion.

Increased nerve growth factor in neurogenic overactive bladder and interstitial cystitis patients

OBJECTIVES

Studies have suggested that pathology of the lower urinary tract can be detected by following changes in urinary proteins. We evaluated urine nerve growth factor (NGF) levels from patients with a variety of urologic conditions to examine NGF's role as a future biomarker.

MATERIALS AND METHODS

Urine samples were obtained from 72 patients with normal non-diseased urinary tracts (n = 13), neurogenic overactive bladder (NOAB) (n = 13), idiopathic overactive bladder (OAB) (n = 17), interstitial cystitis/painful bladder syndrome (IC/PBS) (n = 8), prostate cancer (n = 7), history of prostate cancer status post robot-assisted laparoscopic prostatectomy (RALP) (n = 6), active bladder cancer (n = 4), and nephrolithiasis (n = 4). Urinary NGF levels were measured by enzyme linked immunosorbent assay (ELISA) using the Emax ImmunoAssay System (Promega, Madison, WI, USA); each NGF level was normalized to the patient's urine creatinine (Cr) level. The Bonferroni correction was used to adjust for multiple comparisons.

RESULTS

Urinary NGF/Cr levels were significantly elevated in patients with NOAB (23.02 pg/mg (0-293), p = 0.004) and IC/PBS (31.24 pg/mg (0-291), p = 0.006); and approached significance in patients with nephrolithiasis (19.46 pg/mg (0-85), p = 0.06) compared to controls (0.00 pg/mg (0-12).

CONCLUSIONS

Urinary NGF levels were significantly elevated in patients with NOAB and IC/PBS. Future studies are needed to further examine the significance of urinary NGF levels in the pathogenesis of a variety of urologic diseases and whether NGF could be used as a diagnostic or prognostic marker for specific urologic diseases.

Patients with nephrolithiasis and blood hypertension have higher calciuria than those with isolated nephrolithiasis or hypertension?

AIM

The aim of this study was to determine urinary excretion of calcium, uric acid and sodium and to evaluate insulin resistance in patients with nephrolithiasis and blood hypertension, isolated and in association, and in healthy controls, in absence of obesity and diabetes.

METHODS

The study included 83 non-obese or diabetic patients: 17 with nephrolithiasis and hypertension (group D); 25 with nephrolithiasis (group C); 17 with hypertension (group B) and 24 healthy controls (group A). Urinary analysis was done in 24-hour urine collection and insulin resistance was evaluated through the HOMA-IR index.

RESULTS

Calciuria was higher in group D in relation to groups A (P<0.01), B (P<0.01) and C (P=0.01). There was no significant difference between groups A and B (P=0.32), A and C (P=0.10) and B and C (P=0.68). Correlation analysis between urinary calcium detected strong correlation with uric acid in group A, regular in groups B and C and, strong with sodium in groups B and C. No differences were detected in uric acid and sodium excretion or insulin resistance among groups.

CONCLUSIONS

Patients with blood hypertension and nephrolithiasis present higher calciuria than healthy people, with hypertension or with lithiasis and do not have the positive correlation observed in these latter groups with renal excretion of uric acid and sodium. These results suggest that impaired renal calcium reabsorption in non-obese or diabetic individuals is involved in the association between hypertension and urolithiasis.

[Combined treatment of nephrolithiasis with canephron H]

A total of 35 nephrolithiasis patients aged 26-64 years entered the trial. They were divided into three groups: patients of group 1 (n = 12) received canephron H (50 drops or 2 dragees 3 times a day for 1 month), patients of group 2 (n = 11) were exposed to extracorporeal shock wave lithotripsy (ESWL) followed by standard spasmolytic therapy, patients of group 3 (n = 12) were given canephron H for 1 month before ESWL and 1 month after it in combination with standard therapy. In addition to standard examinations, measurements were made of urinary alkaline phosphatase, lactate dehydrogenase, gamma-glutamyltransferase, N-acetyl-beta-D-glucosaminidase, leucinaminopeptidase. At admission, patients of the three groups had high enzymuria. A course of canephron therapy reduced urinary enzyme levels in groups I and 3 to control levels. Within 24 hours since ESWL patients of groups 2 and 3 demonstrated growth of urinary enzymes (p < 0.05) but in group 3 this rise was less pronounced. On postoperative day 7 enzymuria in groups 2 and 3 diminished (in group 3 enzymuria was close to normal) while in group 2 it was elevated. Thus, canephron H reduces enzymuria and can be used in combined treatment of nephrolithiasis.

[Potentialities of current methods for laboratory analysis in the evaluation of the severity and prevalence of nephrolithiasis in Tajikistan]

The investigation was undertaken to study a relationship between some biogeochemical and environmental factors and nephrolithiasis morbidity rates in the regions of Tajikistan. The paper presents the data of an integrated examination involving biochemical, chromatographic, and mass-spectrometric studies of 1180 patients aged 14 to 76 years who have been treated at the Dushanbe Urology Medical Center. The investigation established a relationship of an increase in ICD morbidity in poor environmental regions of the Republic of Tajikistan to the high organic and non-organic pollution, the high natural mineralization and hardness of water, and the elevated levels of chlorides, sulfates, and other salt components, which in turn influences the severity of a pathological process.