[Show abstract][Hide abstract] ABSTRACT: There is conflicting evidence about the role of obesity in paediatric nephrolithiasis. This Polish study explored the influence of nutritional status and lipid disturbances on urinary lithogenic factors and the risk of kidney stone formation in children and adolescents from three to 18 years of age.
We carried out serum lipid profile evaluations and 24-hour urine chemistry analyses on 493 overweight/obese paediatric participants (mean age 13 years) without nephrolithiasis and 492 healthy normal weight sex and age-matched controls.
A third (33%) of the study group had blood lipid disturbances, with more acidic urine, lower urinary citrate excretion and a higher fraction of ionised calcium and higher Bonn Risk Index than the controls. The participants' body mass index standard deviation score (BMI Z-score) was positively correlated with urinary oxalate and uric acid and negatively correlated with citrate excretion. Total cholesterol, low-density lipoprotein cholesterol and triglycerides correlated negatively with citraturia, while high-density lipoprotein cholesterol correlated positively.
The main factor that predisposed overweight and obese children to kidney stones was hypocitraturia. Urinary citrate excretion was related to both BMI Z-scores and all lipid fraction abnormalities. However, hypercholesterolaemia and particularly low-density lipoprotein hypercholesterolaemia seemed to play a major role. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Background
There are indications that obesity and hyperuricemia may influence the formation and composition of urinary stones. The aim of our study was to determine the effect of obesity and hyperuricemia on the urinary lithogenic risk profile in a large cohort of pediatric patients.
The study population comprised 478 children with urolithiasis and 517 healthy children (reference group). We studied the effects of obesity on the lithogenic profile by dividing the patients with urolithiasis into two groups based on body mass index Z-score (patients who were overweight/obese vs. those with normal weight for age) and comparing the two groups. To study the effect of hyperuricemia on the lithogenic profile, we divided the patients with urolithiasis into two groups based on the presence or not of hyperuricemia (110 patients with urolithiasis accompanied by hyperuricemia vs. 368 patients with urolithiasis and normal serum uric acid levels) and compared the groups.
Among the children and adolescents with urolithiasis and hyperuricemia, there was a significantly lower excretion of crystallization inhibitors (citrates, magnesium). We also found significantly negative correlations between serum uric acid levels and the urine citrate/creatinine ratio (citrate/cr.; r = −0.30, p
Full-text · Article · Nov 2014 · Pediatric Nephrology
[Show abstract][Hide abstract] ABSTRACT: Background:
Among many factors predisposing to monosymptomatic enuresis (MNE) disturbances in urinary electrolites excretion play an important role. Because of many controversies in this field there is a need to debate the role of hypercalciuria in MNE. The aim of our study was to determine the urinary calcium in children with MNE.
The investigation was conducted on 204 children (83 MNE children and 121 reference group). Urinary calcium excretion (in 24-h collection and per kg of body mass), Ca/creatinine ratio, Ca(2+) in urine sample and in 24-h collection of urine were estimated.
Hypercalciuria in MNE group was diagnosed in 18/83 (21.69 %) patients. We found statistically significant differences between children with MNE in Ca(2+) in urine sample and 24-h collection and Ca/creat. ratio. Median urinary calcium excretion (mg/kg/24-h and mmol/24-h) was significantly higher in hypercalciuric enuretic patients. The urinary total calcium (mmol/24-h), urinary bound calcium and urinary calcium concentration (mmol/L) demonstrated a significant positive correlation with height, weight and age in reference group but not in MNE group.
Urinary calcium excretion was significantly disturbed and further studies are needed to assess the role of hypercalciuria in the pathogenesis of MNE.
Full-text · Article · Oct 2014 · Irish Journal of Medical Science
[Show abstract][Hide abstract] ABSTRACT: Crystal formation reflects the entire composition of the surrounding solution. In case of urolithiasis, induced crystal formation in native urine has led to the development of the Bonn-Risk-Index (BRI), a valuable tool to quantify an individual's risk of calcium oxalate urolithiasis. If the progression of a disease is associated with characteristic changes in the activities of urinary components, this leads to an altered urinary crystallisation capacity. Therefore, the results of induced urinary crystal formation can be used to detect and monitor any disease linked to the altered urinary composition. Since crystal formation inherently takes into account the entire urinary composition, the influence of the disease on individual urinary parameters does not have to be known in order to monitor the consequent pathologic alterations. In this paper, we review the background of urinary crystal formation analysis and describe its established application in urolithiasis monitoring as well as potential further fields of clinical application.
Full-text · Article · Aug 2014 · EPMA Journal, The
[Show abstract][Hide abstract] ABSTRACT: Hypocitraturia is considered a major risk factor for calcium stone formation. However, there is no widely accepted reference database of urinary citrate excretion in children. The aim of our study was to determine the amount of citrate eliminated in the urine over a 24-h period in a pediatric cohort and to determine an optimal unit reflecting excretion.
The study cohort comprised 2,334 healthy boys and girls aged 2-18 years. The levels of urinary citrate were assessed by an enzymatic method in 24-hour urine and expressed in absolute values, as urinary concentration, citrate/creatinine ratio, per kilogram of body weight, in relation to 1.73 m(2), and as the calcium/citrate index.
Similar incremental age-related citraturia rates were observed in both male and female subjects until puberty during which time citrate excretion became significantly higher in girls. Urinary citrate adjusted for creatinine and for body weight showed a significantly decreasing trend with increasing age in both sexes. Urinary citrate corrected for body surface was weakly correlated with age. Thus, the assumption of 180 mg/1.73 m(2)/24 h for males and 250 mg/1.73 m(2)/24 h for females as lower cut-off values appeared to be reliable from a practical perspective.
We found distinct sex-dependent differences in citraturia at the start of puberty, with significantly higher values of urinary citrate in girls than in boys. Further prospective studies are warranted to elucidate whether this difference represents a differentiated risk of urolithiasis.
[Show abstract][Hide abstract] ABSTRACT: To determine kidney stone composition in children and to correlate stone fractions with urinary pH and metabolic urinary risk factors.
We studied 135 pediatric patients with upper urinary tract lithiasis in whom excreted or extracted stones were available for analyses. Composition of stones was analyzed. A 24-hour urine assessment included volume, pH and daily excretions of calcium, oxalate, uric acid, cystine, creatinine, phosphate, magnesium and citrate.
Calcium oxalate was the major component of 73% stones, followed by struvite (13%) and calcium phosphate (9%). Uric acid was present in almost half of stones, but in rudimentary amounts. The calcium oxalate content in calculi showed a strong relationship with calciuria, and moderate association with oxaluria, magnesuria and acidification of urine. The percent content of struvite presented reverse and lower correlations with regard to the above parameters. Calcium phosphate stone proportion had low associations with urinary risk factors.
Calciuria, oxaluria, magnesuria and low urine pH exerted the biggest influence on calcium oxalate content in pediatric renal stones. Relationships of urinary risk factors with calculi calcium phosphate content were of unclear significance. Urinary citrate excretion did not significantly correlate with kidney stone composition in children.
Full-text · Article · Aug 2013 · Journal of pediatric urology
[Show abstract][Hide abstract] ABSTRACT: Background
Hypercalciuria and hypocitraturia are considered the most important risk factors for urolithiasis. Citrate binds to urinary calcium to form a soluble complex which decreases the availability of ionized calcium (Ca2+) necessary for calcium oxalate formation and phosphate crystallization. The aims of this study were to assess the Ca2+ fraction in relation to total calciuria, citraturia and urinary pH and to determine whether urinary Ca2+ concentration is a helpful biomarker in metabolic evaluation of children with urolithiasis.
We collected 24-h urine samples from 123 stone-forming children and adolescents with hypocitraturia and from 424 healthy controls. Total calciuria (total calcium, Catotal), Ca2+, pH, citrate, oxalate and Bonn Risk Index (BRI) were assessed and compared between the two groups.
Total calciuria and Ca2+ content were higher in stone-formers than in the healthy children. In both stone-formers and controls, Ca2+ content was inversely related to citraturia and urinary pH, whereas the Ca2+/Catotal ratio differed slightly between the groups. A large variability in Ca2+ level was found across individuals in both groups. The BRI increased with increasing calciuria and urine acidity.
Compared to controls, stone-formers with hypocitraturia demonstrated a higher urinary Ca2+ concentration, but this was proportional to calciuria. The large individual variability in urinary Ca2+ content limits its practical use in metabolic evaluation of children with urolithiasis. However, the Ca/Citrate ratio may be a useful clinical tool in evaluating children with urolithiasis.
[Show abstract][Hide abstract] ABSTRACT: Objective:
Myelomeningocele is the most common physically disabling birth defect in humans. It is caused by the failure of the neural tube to close and is most common in the lumbosacral area. Because of associated neurogenic bladder dysfunction, children with myelomeningocele have an increased risk of urinary tract infections and, ultimately, of kidney damage. Nerve growth factor (NGF) is an important mediator inducing bladder overactivity in many pathological conditions. The aim of this study was to evaluate urinary NGF excretion in children with neurogenic bladder caused by myelomeningocele.
Material and methods:
The investigation was conducted into two groups. Group 1 comprised 28 children with neurogenic bladder, and group 2 comprised 20 healthy children with no abnormalities in the urinary and nervous systems. Urinary NGF levels were measured by enzyme-linked immunosorbent assay.
Median urinary NGF concentration in group 1 was higher when compared with healthy controls. Positive correlations between urinary NGF level and detrusor pressure at maximum bladder capacity, and negative correlations between NGF and bladder wall compliance were found.
Urinary NGF levels were significantly elevated in patients with myelomeningocele. Future studies are needed to examine further the significance of urinary NGF levels in the pathogenesis of neurogenic bladder in this clinical condition.
Full-text · Article · Jan 2013 · Scandinavian Journal of Urology
[Show abstract][Hide abstract] ABSTRACT: Introduction: Urolithiasis is increasingly being diagnosed in children. Some of the major risk factors for kidney stones are hipercalciuria, hiperoxaluria, hipocitraturia and hydrogen ion content measured by pH. Recently, more and more attention is being paid to the impact of diabetes type 1 and 2 on the development of nephrolithiasis especially in periods of poor metabolic control. Aim of the study was to evaluate the BRI (bonn risk index - rate of spontaneous crystallization of calcium oxalate), the concentration of oxalate, citrate and urine pH in children with acid-base balance disturbances occurring in patients with newly diagnosed type 1 diabetes (DMT1). Material and methods: The study group included 40 patients aged 6 to 17 years (average age±SD: 12,58±3,33) with newly diagnosed DMT1. The study was performed twice: at the beginning of the disease, immediately after the treatment of diabetic ketoacidosis (study I) and after obtaining satisfactory metabolic control (study II), that is after about two weeks. The control group consisted of 100 children (6-17 years, average age 12,34±3,96) without symptoms suggestive of urolithiasis. In every child, a 24-hour urine sample was collected. BRI was implemented in the urine by his own semi-micro method. Results: Ionized calcium level was significantly higher immediately after the diagnosis of type 1 diabetes compared to the control group (0,68±0,67 vs. 0,40±0,18 mmol/l; p<0,001) and to study II (0,68±0,67 vs. 0,28±0,23 mmol/l; p=0,008). BRI value was significantly higher in early onset compared to the control group and the study II (3,18±5,54 vs. 0,66±0,52, p<0,001; 3,18±5,54 vs. 0,64±1,56; p=0,034). BRI correlated inversely with pH at admission to the hospital (r=-0,53, p=0,0023). Conclusions: Metabolic alterations occurring during diabetic ketoacidosis at diagnosis of new type 1 diabetes may predispose to the development of the urinary stones, and thereby to the kidney damage.
No preview · Article · Nov 2012 · Pediatric endocrinology
[Show abstract][Hide abstract] ABSTRACT: Childhood obesity is becoming a worldwide epidemic and its metabolic and cardiovascular complications may already be evident at a young age. Several epidemiologic studies in adults have clearly demonstrated that obesity and overweight increase the risk of kidney disease and urolithiasis.
The purpose of this study was to evaluate the relationship between overweight and obesity and urolithiasis risk factors in children.
The main kidney stones risk factors in urine such as calcium concentration, oxalate concentration, citrate concentration, pH of urine as well as BRI (Bonn Risk Index) were analyzed in 249 overweight and obese children (study group) and in 281 children with normal weight (control) at the age of 3 to 18 years old.
In the study group the mean oxalate concentration was significantly higher than in the control (0.52±0.48 vs. 0.26±0.12; p <0.05). The mean calcium concentration of overweight/obese patients was higher than that of normal body weight and the difference was close to statistically significant (3.23±2.55 vs 2.58±1.59; p=0.0537). The mean urine pH in the study group was 6.28±0.46 and was significantly lower (p <0.05) than the mean urine pH in the control, witch was 6.40±0.47. The mean citrate concentration among overweight/obese patients was significantly lower than in control (431,2±309,5 vs. 637,2±310,7; p <0.05).
Our results suggest that obesity or overweight at a young age are associated with an increased risk of kidney stones. Weight loss might be explored as a potential treatment to prevent kidney stone formation.
No preview · Article · Jul 2012 · Pediatric endocrinology
[Show abstract][Hide abstract] ABSTRACT: Hyperhomocysteinemia is independent risk factor of cardiovascular diseases. Similarly to nephrotic syndrome (NS) predisposes to vein thrombosis.
To evaluate serum and urinary total homocysteine (stHcy and utHcy) levels in children with the symptoms of SN, and to determine a correlation between its concentration and some parameters of hemostasis, as well as doses and the time of prednisone therapy and serum cortisol level.
The examined group consisted of 18 children with NS, aged 7.64 +/- 5.1 years, divided on two groups: A--in time o proteinuria; B--during treatment with prednisone after regression of proteinuria. Control group (C) consisted of 20 children, aged 8.5 +/- 3.6 years. Serum and urinary tHcy levels were assayed by enzyme-linked immunosorbent assay method using the Axis-Shield set.
Serum total Hcy concentration in groups A and B did not differ from the control group (p > 0.05). Urinary total Hcy concentration in groups A and B was significantly higher than that of control (p < 0.05). A positive correlation was observed between stHcy and serum albumin as well as cortisol levels, and between utHcy and serum AT III level.
In children with steroid-dependent NS, subclinical disturbances in hemostasis were independent of serum tHcy concentration. There was no correlation between serum tHcy and cumulated doses, as well as time of prednisone treatment, however positive correlation was found with serum cortisone. Urinary excretion of Hcy significantly increases, in comparison to control, and correlates with serum AT III level.
No preview · Article · Oct 2011 · Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego
[Show abstract][Hide abstract] ABSTRACT: Although autistic spectrum disorders (ASD) are a strongly genetic condition certain metabolic disturbances may contribute to clinical features. Metabolism of oxalate in children with ASD has not yet been studied.
The objective was to determine oxalate levels in plasma and urine in autistic children in relation to other urinary parameters.
In this cross-sectional study, plasma oxalate (using enzymatic method with oxalate oxidase) and spontaneous urinary calcium oxalate (CaOx) crystallization (based on the Bonn-Risk-Index, BRI) were determined in 36 children and adolescents with ASD (26 boys, 10 girls) aged 2-18 years and compared with 60 healthy non-autistic children matched by age, gender and anthropometric traits.
Children with ASD demonstrated 3-fold greater plasma oxalate levels [5.60 (5th-95th percentile: 3.47-7.51)] compared with reference [(1.84 (5th-95th percentile: 0.50-4.70) μmol/L (p < 0.05)] and 2.5-fold greater urinary oxalate concentrations (p < 0.05). No differences between the two groups were found in urinary pH, citraturia, calciuria or adjusted CaOx crystallization rates based on BRI. Despite significant hyperoxaluria no evidence of kidney stone disease or lithogenic risk was observed in these individuals.
Hyperoxalemia and hyperoxaluria may be involved in the pathogenesis of ASD in children. Whether this is a result of impaired renal excretion or an extensive intestinal absorption, or both, or whether Ox may cross the blood brain barrier and disturb CNS function in the autistic children remains unclear. This appears to be the first report of plasma and urinary oxalate in childhood autism.
Full-text · Article · Sep 2011 · European journal of paediatric neurology: EJPN: official journal of the European Paediatric Neurology Society
[Show abstract][Hide abstract] ABSTRACT: The Bonn Risk Index has been used to evaluate the risk of urinary calcium oxalate stone formation. According to the original method, risk should be determined based on 24-hour urine collection. We studied whether the Bonn Risk Index could be measured in spot urine samples and which part of the day is most suitable for this purpose.
We collected total and fractionated 24-hour urine (in a 6-hour nocturnal portion and 9 consecutive 2-hour diurnal samples) in 42 children and adolescents with calcium oxalate urolithiasis and 46 controls. Bonn Risk Index values determined from each of the urine fractions were compared to those obtained from related 24-hour urine collections.
Both groups exhibited similar circadian patterns of Bonn Risk Index values. Median Bonn Risk Index for the nighttime portion of urine in the stone group was 1.4 times higher than that obtained from the total 24-hour urine. The morning hours between 08:00 and 10:00 showed the peak lithogenic risk, and this fraction had the highest sensitivity and selectivity regarding discrimination between stone formers and healthy subjects. The afternoon hours demonstrated lower and less fluctuating crystallization risk. Despite diurnal fluctuations in Bonn Risk Index, there was still a well-defined cutoff between the groups.
Bonn Risk Index determined from urine samples collected between 08:00 and 10:00 appears optimal in separating stone formers from healthy subjects, and appears as useful as the value determined from 24-hour urine collection. Investigation of this diurnal sample simplifies diagnosis in pediatric stone disease without loss of clinical information.
Full-text · Article · Nov 2010 · The Journal of urology
[Show abstract][Hide abstract] ABSTRACT: The Bonn Risk Index has been used to evaluate the risk of urinary calcium oxalate stone formation. According to the original method, risk should be determined based on a 200 ml urine sample taken from a 24-hour collection. We evaluated whether the Bonn Risk Index can also be effectively determined in small urine samples.
We studied 190 children and adolescents with nocturia and calcium oxalate urolithiasis. Initially Bonn Risk Index was determined according to the original method of Laube. Subsequently Bonn Risk Index was calculated using a computer program controlling a specially designed system to define the time point of induced crystallization based on consecutive urine samples of 1.5, 2.0 and 3.0 ml.
No significant differences were found in Bonn Risk Index between values obtained from 200 ml samples and those based on the micromethod with urine samples of 2 and 3 ml.
Assessment of risk of urinary calcium oxalate stone formation with Bonn Risk Index in small urine volumes, based on prototype equipment controlled by specialized computer software, is comparable to the original method. This finding facilitates the procedure and improves Bonn Risk Index determination in children.
Full-text · Article · Mar 2010 · The Journal of urology
[Show abstract][Hide abstract] ABSTRACT: The mechanisms underlying cartilage matrix degradation in joint diseases is not fully understood but reactive oxygen species are implicated as main causative factors. Comparative studies of glutathione reductase (GR) activity in synovial fluid from patients with rheumatoid arthritis (RA), reactive arthritis (ReA) and osteoarthritis (OA) as well as correlations between GR activity and concentration of the major cartilage components in synovial fluid are presented in this study. We found significantly higher activity of GR in RA (about three-fold) and ReA (about two-fold) than in OA. In RA and ReA patients, GR activity in synovial fluid correlates negatively with the concentrations of collagen and degradation products of sulfated glycosaminoglycans. In OA patients the activity of GR was significantly lower than in RA and ReA, which positively correlated with the concentration of collagen and showed a tendency for positive correlation with the degradation products of sulfated glycosaminoglycans. Our results suggest that in RA and ReA patients increased activity of GR does not prevent the increased degradation of collagen and proteoglycans by ROS.
Preview · Article · Oct 2009 · Acta biochimica Polonica
[Show abstract][Hide abstract] ABSTRACT: In small children, pyelonephritis (PN) is an important cause of scarring in the renal and disturbed in the production and degradation of extracellulare matrix proteins (ECM). Aim of the study was to assess the urinary levels metalloproteinases 2 and 9 (MMP-2 and MMP-9) and their inhibitors 1 and 2 (TIMP-1 and TIMP-2) in children with pyelonephritis (PN).
Study group (I) consisted of 42 children with PN, aged 1-15 years, examined twice: A--prior to treatment (1-3 days of fever), B--after antibacterial treatment (10-14 days). The control group (K) consisted of 30 healthy children. Enzyme-linked immunosorbent assay kits were used for measurements of total human MMP-2, MMP-9, TIMP-1 and TIMP-2 in first morning urine.
In children with PN (I) prior to treatment (A), urinary concentration of all parameters were increased as compared to the control (K) (p<0.05). After treatment (B), only the levels of TIMP-1 was still elevated (p = 0.02). In PN before (A) and after (B) treatment MMP-9/TIMP-1 ratio. However MMP-2/TIMP-2 ratio was normal.
In children with PN the balance MMP-9/TIMP-1 is disturbed, with the predominance of TIMP-1 production over MMP-9. It may lead to renal fibrosis.
Full-text · Article · Aug 2009 · Polski merkuriusz lekarski: organ Polskiego Towarzystwa Lekarskiego
[Show abstract][Hide abstract] ABSTRACT: Idiopathic hypercalciuria is the most important predisposing risk factor for calcium oxalate (CaOx) renal stone formation. We assessed the associations between spontaneous CaOx crystallization based on the Bonn Risk Index (BRI), urinary pH, calciuria, oxaluria, and citraturia in 140 Caucasian patients with hypercalciuria, aged 4-17 years, and compared the findings with those in 210 normocalciuric controls. Of the 140 hypercalciuric patients, 58 had renal stones, and 82 had recurrent erythrocyturia, renal colic, or urinary obstructive symptoms-but without stones. Urinary ionized calcium ([Ca(2+)]) levels were measured using a selective electrode, while the onset of crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox(2-)). The calculation of the BRI was based on the [Ca(2+)]:Ox(2-) ratio. The BRI values were 12-fold higher in hypercalciuric children than in healthy controls, but no differences were found in the BRI between subjects with urinary stones and those with urolithiasis-like symptoms. An increased BRI suggested an association with hypercalciuria, lower urinary pH, hypocitraturia, and hypooxaluria. These data indicate that hypercalciuria is an important factor associated with increased urinary CaOx crystallization, although the causal pathways need further investigation. Determination of the BRI in children with hypercalciuria may improve the risk assessment of kidney stones.
Full-text · Article · May 2009 · Pediatric Nephrology
[Show abstract][Hide abstract] ABSTRACT: Published data on the association between calcium oxalate (CaOx) crystallization and kidney stone disease in children are scarce. The aims of this study were to determine CaOx crystallization using the Bonn Risk Index (BRI) in children with urolithiasis in comparison to healthy controls, to evaluate the relationships between BRI and urinary parameters, such as pH, calciuria, oxaluria and citraturia, and to assess the association between BRI and the size of renal stones. We compared the BRI in 142 Caucasian children and adolescents (76 girls, 66 boys) aged 3-18 years with kidney stones and 210 healthy age- and sex-matched controls without urolithiasis. Urinary ionized calcium ([Ca2+]) was measured using a selective electrode, while the onset of spontaneous crystallization was determined using a photometer and titration with 40 mmol/L ammonium oxalate (Ox2-). The calculation of the BRI value was based on the Ca2+:Ox2- ratio. High-resolution renal ultrasonography was carried out to estimate the size of the renal stones. The BRI values were 15-fold higher in children with renal stones than in healthy children without stones. The same trend was shown by BRI/kg body weight (tenfold greater in children with renal stones than in healthy children without stones), BRI/per 1.73 m2 body surface (13-fold greater) and BRI/body mass index (23-fold greater). No association was observed between BRI and the diameter of stones. Children with kidney stones, both males and females, had an increased BRI compared with subjects without urolithiasis. High BRI suggests an association with lower urinary pH, hypercalciuria, hyperoxaluria or hypocitraturia, which are all risk factors of kidney stones. An increased BRI in children, although unrelated to renal stone size, reflects the risk of calcium oxalate crystallization and may indicate early metabolic disorders leading to urolithiasis.
Full-text · Article · Aug 2008 · Pediatric Nephrology