RESUMEN
Uric acid lithiasis accounts for about 10% of all types of renal lithiasis. The most common causes of uric acid lithiasis are low urinary pH, followed by high concentration of urinary uric acid, and low diuresis. Treatment of patients consists of alkalinization of urine, reducing the consumption of purine-rich foods, and administration of xanthine oxidase inhibitors, because there are no established therapeutic inhibitors of uric acid crystallization. We recently found that theobromine inhibited uric acid crystallization in vitro, and that the increased urinary level of theobromine following its oral consumption was associated with the prevention of uric acid crystallization. In this study, we evaluated the inhibitory effects of theobromine metabolites and other methylxanthine-related compounds on uric acid crystallization. We also measured the urinary concentrations of theobromine and its metabolites in samples from healthy individuals and patients with uric acid stones and compared the extent of uric acid supersaturation and uric acid crystal formation in these different samples. Theobromine and other methylxanthines that lacked a substituent at position 1 inhibited uric acid crystallization, but other methylxanthines did not have this effect. Individuals with clinical parameters that favored uric acid crystallization did not develop uric acid crystals when theobromine and its metabolites were in the urine at high levels. Thus, theobromine and its metabolites reduced the risk of uric acid lithiasis.
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Litiasis , Nefrolitiasis , Humanos , Ácido Úrico/química , Teobromina , Preparaciones FarmacéuticasRESUMEN
PURPOSE: Uric acid renal lithiasis has a high prevalence and a high rate of recurrence. Removal of uric acid stones can be achieved by several surgical techniques (extracorporeal shock wave lithotripsy, endoscopy, laparoscopy, open surgery). These stones can also be eliminated by dissolution within the kidneys, because the solubility of uric acid is much greater when the pH is above 6. At present, N-acetylcysteine with a urinary basifying agent is the only treatment proposed to increase the dissolution of uric acid stones. In this paper, we compare the effect of theobromine and N-acetylcysteine on the in vitro dissolution of uric acid calculi in artificial urine at pH 6.5. METHODS: The dissolution of uric acid renal calculi was performed in a temperature-controlled (37 °C) chamber. A peristaltic pump was used to pass 750 mL of synthetic urine (pH 6.5) through a capsule every 24 h. Stone dissolution was evaluated by measuring the change in weight before and after each experiment. RESULTS: N-acetylcysteine increased the dissolution of uric acid calculi, but the effect was not statistically significant. Theobromine significantly increased the dissolution of uric acid calculi. Both substances together had the same effect as theobromine alone. The addition of theobromine to a basifying therapy that uses citrate and/or bicarbonate is a potential new strategy for the oral chemolysis of uric acid stones. CONCLUSION: Theobromine may prevent the formation of new stones and increase the dissolution of existing stones.
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Cálculos Renales , Ácido Úrico , Acetilcisteína/uso terapéutico , Humanos , Cálculos Renales/química , Solubilidad , Teobromina/uso terapéuticoRESUMEN
Phytate has been classified as an anti-nutrient, but there are no adverse effects from the consumption of a balanced diet with 1 to 2 g of daily phytate (inositol-hexaphosphate, InsP6) as a calcium magnesium salt, the form naturally present in grains. Furthermore, recent research has shown that phytate consumption may prevent pathological calcifications, such as kidney stones and cardiovascular calcifications. However, many endogenous and exogenous enzymes can hydrolyze phytate to lower inositol phosphates (InsPs) that also have biological activity. We performed a controlled hydrolysis of phytate and identified the products (InsPs) using tandem mass spectrometry (MS/MS). The total level of all InsPs was measured using a non-specific methodology. In addition, we evaluated the effects of the InsP6 hydrolysates on calcium oxalate crystallization using scanning electron microscopy and measuring the time needed for the induction of crystallization. Our results indicate that InsP6 and its hydrolysis products functioned as effective inhibitors of calcium oxalate crystallization. Thus, even though InsP6 is hydrolyzed after consumption, the enzymatic products also have the potential to reduce pathological calcifications. Finally, although it is useful to measure the overall level of InsPs in biological fluids, such as urine, there is a need to develop simple analytical methods to quantify the level of individual InsPs.
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Oxalato de Calcio , Ácido Fítico , Calcio/química , Cristalización , Fosfatos de Inositol , Magnesio , Ácido Fítico/farmacología , Espectrometría de Masas en TándemRESUMEN
INTRODUCTION AND PURPOSE: Distal renal tubular acidosis (DRTA) is a metabolic disorder that associates urolithiasis and urinary pH > 6. The prevalence of DRTA in patients with calcium phosphate stones is not well known. The objective is to determine the prevalence of DRTA in patients with calcium phosphate stones and urinary pH above 6 based on the furosemide test. METHODS: A total of 54 patients with calcium phosphate stones and urinary pH above 6.0 were submitted to the furosemide test. The association of DRTA with age, sex, type of stone, stone recurrence, stone bilaterality, 24-h urine biochemistry, and adverse effects of the furosemide test were examined. RESULTS: The furosemide test indicated that 19 of 54 patients (35.2%) had DRTA. The sex ratio was similar in the two groups (p < 0.776). The DRTA group was significantly younger (p < 0.001), and had a higher prevalence of bilateral stones (p < 0.001), a higher prevalence of recurrent stones (p < 0.04), a lower plasma potassium level (p < 0.001), a higher urinary Ca level (p ≤ 0.05), and a lower urinary citrate level (p < 0.001). None of the patients reported adverse effects from the furosemide test. CONCLUSIONS: There was a high prevalence of DTRA in patients with urinary pH above 6 and calcium phosphate stones. Young age, bilateral stones, stone recurrence, hypercalciuria, hypocitraturia, and plasma hypokalemia were associated with DRTA. None of the patients reported adverse effects of the furosemide test.
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Acidosis Tubular Renal/epidemiología , Fosfatos de Calcio , Cálculos Urinarios/química , Cálculos Urinarios/epidemiología , Acidosis Tubular Renal/diagnóstico , Adulto , Distribución por Edad , Ácido Cítrico/orina , Técnicas de Diagnóstico Urológico , Diuréticos , Femenino , Furosemida , Humanos , Concentración de Iones de Hidrógeno , Hipercalciuria/epidemiología , Hipercalciuria/orina , Hipopotasemia/sangre , Hipopotasemia/epidemiología , Masculino , Persona de Mediana Edad , Prevalencia , RecurrenciaRESUMEN
BACKGROUND: Encrustation of ureteral double J stents is a common complication that may affect its removal. The aim of the proposed study is to evaluate the efficacy and safety of a new oral composition to prevent double J stent encrustation in indwelling times up to 8 weeks. METHODS: A double-blinded, multicenter, placebo-controlled trial was conducted with 105 patients with indwelling double J stents enrolled across 9 public hospitals in Spain. The patients were randomly assigned (1:1) into intervention (53 patients) or placebo (52 patients) groups for 3 to 8 weeks and both groups self-monitored daily their morning urine pH levels. The primary outcome of analysis was the degree of stent ends encrustation, defined by a 4-point score (0 - none; 3 - global encrustation) using macroscopic and electron microscopy analysis of crystals, after 3 to 8-w indwelling period. Score was exponentially transformed according to calcium levels. Secondary endpoints included urine pH decrease, stent removal, and incidence of adverse events. RESULTS: The intervention group benefits from a lower global encrustation rate of stent ends than placebo group (1% vs 8.2%; p < 0.018). Mean encrustation score was 85.12 (274.5) in the placebo group and 18.91 (102.27) in the intervention group (p < 0.025). Considering the secondary end points, treated patients reported greater urine pH decreases (p = 0.002). No differences in the incidence of adverse events were identified between the groups. CONCLUSIONS: Our data suggest that the use of this new oral composition is beneficial in the context of ureteral double J indwelling by decreasing mean, as well as global encrustation. TRIAL REGISTRATION: This trial was registered at www.clinicaltrials.gov under the name "Combined Use of a Medical Device and a Dietary Complement in Patient Urinary pH Control in Patients With an Implanted Double J Stent" with date 2nd November 2017, code NCT03343275, and URL.
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Calcinosis/etiología , Calcinosis/prevención & control , Metionina/administración & dosificación , Ácido Fítico/administración & dosificación , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Stents/efectos adversos , Uréter/cirugía , Administración Oral , Adulto , Cristalización , Método Doble Ciego , Femenino , Humanos , Concentración de Iones de Hidrógeno , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Falla de Prótesis , Orina/químicaRESUMEN
Phytate (myo-inositol hexaphosphate, InsP6) is an important component of seeds, legumes, nuts, and whole cereals. Although this molecule was discovered in 1855, its biological effects as an antinutrient was first described in 1940. The antinutrient effect of phytate results because it can decrease the bioavailability of important minerals under certain circumstances. However, during the past 30 years, researchers have identified many important health benefits of phytate. Thus, 150 years have elapsed since the discovery of phytate to the first descriptions of its beneficial effects. This long delay may be due to the difficulty in determining phytate in biological media, and because phytate dephosphorylation generates many derivatives (InsPs) that also have important biological functions. This paper describes the role of InsP6 in blocking the development of pathological calcifications. Thus, in vitro studies have shown that InsP6 and its hydrolysates (InsPs), as well as pyrophosphate, bisphosphonates, and other polyphosphates, have high capacity to inhibit calcium salt crystallization. Oral or topical administration of phytate in vivo significantly decreases the development of pathological calcifications, although the details of the underlying mechanism are uncertain. Moreover, oral or topical administration of InsP6 also leads to increased urinary excretion of mixtures of different InsPs; in the absence of InsP6 administration, only InsP2 occurs at detectable levels in urine.
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Calcinosis/tratamiento farmacológico , Calcinosis/patología , Ácido Fítico/uso terapéutico , Animales , Calcio , Cristalización , Humanos , Fosfatos de Inositol/farmacología , Ácido Fítico/administración & dosificaciónRESUMEN
Background/aim: This study was designed to evaluate the relationship between urinary phytate concentration and risk of fracture at 10 years, determined by using the FRAX model, in women who had undergone menopause within 5 years of the time of enrollment. Materials and methods: Of the 212 postmenopausal women evaluated, 69 were excluded because they had urinary phytate concentrations between 0.51 and 0.99 mg/L. Of the remaining 143 women, 91 had low (≤0.50 mg/L) and 52 had high (≥1.0 mg/L) urinary phytate concentrations. The 10-year risk of fracture was calculated by using the FRAX model. Results: The risks of major osteoporotic fracture and hip fracture were higher in women with low urinary phytate levels (P < 0.001 in both cases). Evaluation of the risk of hip fracture in women with and without risk factors for osteoporosis (e.g., tobacco, alcohol, and drug consumption) and according to urinary phytate concentrations indicated that, among women with no risk factors, those with low and high urinary phytate levels had a range of risks of 0%0.6% and 0%0.3%, respectively (P = 0.098). Moreover, among women with at least one risk factor, those with low and high urinary phytate had a range of risks of 0.1%0.8% and 0.1%0.4%, respectively (P = 0.002). Similar results were observed when the risks of major osteoporotic fracture were analyzed. Conclusion: These results indicate the relationship of phytate with the risks of major osteoporotic fracture and hip fracture, with these differences being more marked in women with risk factors for osteoporosis. From this study follows the importance of the consumption of phytate-rich products (nuts, legumes, whole cereals) to protect against the risk of fracture in 10 years, mainly in women with risk factors for osteoporosis.
Asunto(s)
Densidad Ósea/fisiología , Osteoporosis Posmenopáusica/orina , Fracturas Osteoporóticas/patología , Fracturas Osteoporóticas/orina , Ácido Fítico/orina , Posmenopausia/orina , Absorciometría de Fotón , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/diagnóstico por imagen , Fracturas Osteoporóticas/diagnóstico por imagen , Proyectos Piloto , Posmenopausia/fisiología , Medición de Riesgo , Factores de RiesgoRESUMEN
BACKGROUND: The diagnosis and follow-up of stone forming patients is usually performed by analysis of 24-h urine samples. However, crystallization risk varies throughout the day, being higher at night. The main objective of this study is to evaluate the urinary crystallization risk in adults and children by calculating risk indexes based on different collection periods. METHODS: The study included 149 adults (82 healthy and 67 stone-formers) and 108 children (87 healthy and 21 stone-formers). 24-h urine was collected, divided into 12-h daytime sample (8 am to 8 pm), and 12-h overnight sample (8 pm to 8 am next morning). Solute concentrations, the calcium to citrate ratio (Ca/Cit), and the ion activity product of calcium oxalate (AP[CaOx]) and calcium phosphate (AP[CaP]) were calculated in each 12-h sample and in overall 24-h urine. Assessments were also related to stone type. RESULTS: Ca/Cit and AP(CaOx) were significantly higher in stone forming patients than in healthy subjects. The 12-h overnight samples had the highest values for both risk indexes, confirming a greater risk for crystallization at night. The AP(CaP) index was significantly higher in patients with pure hydroxyapatite stones than healthy controls, but was not significantly different between stone-formers overall and healthy controls. CONCLUSIONS: The calculation of risk indexes is a simple method that clinicians can use to estimate crystallization risk. For this purpose, the use of 12-h overnight urine may be a reliable alternative to 24-h collections.
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Cálculos Urinarios/diagnóstico , Toma de Muestras de Orina/métodos , Adulto , Calcio/orina , Oxalato de Calcio/orina , Fosfatos de Calcio/orina , Niño , Ácido Cítrico/orina , Cristalización , Humanos , Factores de Riesgo , Factores de Tiempo , Urinálisis/métodos , Cálculos Urinarios/químicaRESUMEN
BACKGROUND: Fructose intake, mainly as table sugar or high fructose corn syrup, has increased in recent decades and is associated with increased risk for kidney stones. We hypothesized that fructose intake alters serum and urinary components involved in stone formation. METHODS: We analyzed a previously published randomized controlled study that included 33 healthy male adults (40-65 years of age) who ingested 200 g of fructose (supplied in a 2-L volume of 10% fructose in water) daily for 2 weeks. Participants were evaluated at the Unit of Nephrology of the Mateo Orfila Hospital in Menorca. Changes in serum levels of magnesium, calcium, uric acid, phosphorus, vitamin D, and intact PTH levels were evaluated. Urine magnesium, calcium, uric acid, phosphorus, citrate, oxalate, sodium, potassium, as well as urinary pH, were measured. RESULTS: Ingestion of fructose was associated with an increased serum level of uric acid (p < 0.001), a decrease in serum ionized calcium (p = 0.003) with a mild increase in PTH (p < 0.05) and a drop in urinary pH (p = 0.02), an increase in urine oxalate (p = 0.016) and decrease in urinary magnesium (p = 0.003). CONCLUSIONS: Fructose appears to increase urinary stone formation in part via effects on urate metabolism and urinary pH, and also via effects on oxalate. Fructose may be a contributing factor for the development of kidney stones in subjects with metabolic syndrome and those suffering from heat stress. TRIAL REGISTRATION: ClinicalTrials.gov NCT00639756 March 20, 2008.
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Fructosa/efectos adversos , Respuesta al Choque Térmico/fisiología , Cálculos Renales/inducido químicamente , Cálculos Renales/orina , Síndrome Metabólico/inducido químicamente , Síndrome Metabólico/orina , Adulto , Anciano , Oxalato de Calcio/orina , Fructosa/administración & dosificación , Respuesta al Choque Térmico/efectos de los fármacos , Humanos , Cálculos Renales/epidemiología , Masculino , Síndrome Metabólico/epidemiología , Persona de Mediana Edad , Factores de Riesgo , Ácido Úrico/orinaRESUMEN
Mesoamerican nephropathy (MeN), an epidemic in Central America, is a chronic kidney disease of unknown cause. In this article, we argue that MeN may be a uric acid disorder. Individuals at risk for developing the disease are primarily male workers exposed to heat stress and physical exertion that predisposes to recurrent water and volume depletion, often accompanied by urinary concentration and acidification. Uric acid is generated during heat stress, in part consequent to nucleotide release from muscles. We hypothesize that working in the sugarcane fields may result in cyclic uricosuria in which uric acid concentrations exceed solubility, leading to the formation of dihydrate urate crystals and local injury. Consistent with this hypothesis, we present pilot data documenting the common presence of urate crystals in the urine of sugarcane workers from El Salvador. High end-of-workday urinary uric acid concentrations were common in a pilot study, particularly if urine pH was corrected to 7. Hyperuricemia may induce glomerular hypertension, whereas the increased urinary uric acid may directly injure renal tubules. Thus, MeN may result from exercise and heat stress associated with dehydration-induced hyperuricemia and uricosuria. Increased hydration with water and salt, urinary alkalinization, reduction in sugary beverage intake, and inhibitors of uric acid synthesis should be tested for disease prevention.
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Ejercicio Físico , Trastornos de Estrés por Calor/etiología , Insuficiencia Renal Crónica/etiología , Ácido Úrico/orina , Adulto , América Central , Cristalización , Humanos , MasculinoRESUMEN
OBJECTIVE: The aim of this study was to evaluate the relationship between physiological levels of myo-inositol hexaphosphate (phytate) and cardiovascular (CV) calcification in patients with chronic kidney disease (CKD). DESIGN AND METHODS: This was a prospective cross-sectional study conducted from December 2012 to June 2013. SUBJECTS: Sixty-nine consecutive patients with CKD who were not undergoing renal replacement therapy. INTERVENTION: All subjects were given lateral lumbar X-rays to quantify abdominal aortic calcification (AAC). Clinical laboratory analyses and phytate food frequency questionnaires were also performed. MAIN OUTCOME MEASURE: Phytate urinary excretion, estimated phytate consumption (based on food frequency questionnaire) and AAC score. Patients were divided into two groups based on median abdominal aortic calcification (AAC) score: no/mild AAC (AAC ≤ 6, n = 35) and moderate/severe AAC (AAC > 6, n = 34). RESULTS: Patients with no/mild AAC were younger, had lower pulse pressure, greater dietary intake of phytate, greater urinary phytate and the prevalence of prior CV disease was significantly lower compared to patients with moderate/severe AAC. Among the top 10 phytate-rich foods, lentil consumption was significantly greater in patients with no/mild AAC than in those with moderate/severe AAC. Multivariate logistic regression analysis indicated that age, prior CV disease, urinary phytate (or lentil consumption) were independently associated to AAC. CONCLUSION: Our results suggest that adequate consumption of phytate can prevent AAC in patients with CKD. Further prospective studies must be performed to elucidate the benefits of a phytate-rich diet and the associated risk of phosphorus bioavailability in these patients.
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Aorta Abdominal/patología , Dieta , Ácido Fítico/administración & dosificación , Insuficiencia Renal Crónica/patología , Calcificación Vascular/patología , Anciano , Aorta Abdominal/diagnóstico por imagen , Índice de Masa Corporal , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ácido Fítico/orina , Prevalencia , Estudios Prospectivos , Factores de Riesgo , Encuestas y Cuestionarios , Resultado del Tratamiento , Calcificación Vascular/diagnóstico por imagen , Circunferencia de la CinturaRESUMEN
PURPOSE: The main aim of the current study was to evaluate the effectiveness of mixtures of magnesium, citrate and phytate as calcium oxalate crystallization inhibitors. MATERIALS AND METHODS: A turbidimetric assay in synthetic urine was performed to obtain induction times for calcium oxalate crystallization in the absence and presence of different mixtures of inhibitors. The morphology of calcium oxalate crystals in the absence or presence of inhibitors and mixtures of the inhibitors was evaluated in 2 crystallization experiments at low and high calcium oxalate supersaturation. The crystals formed were examined using scanning electron microscopy. RESULTS: Examination of crystallization induction times revealed clear inhibitory effects of magnesium, citrate and phytate on calcium oxalate crystallization, supporting usefulness in the treatment and prevention of calcium oxalate nephrolithiasis. Significant synergistic effects between magnesium and phytate were observed. Scanning electron microscopy images revealed that phytate is a powerful crystal growth inhibitor of calcium oxalate, totally preventing the formation of trihydrate and monohydrate. In addition to crystallization inhibition capacity, citrate and magnesium avoided calcium oxalate crystallization by decreasing its supersaturation. CONCLUSIONS: The synergistic effect between magnesium and phytate on calcium oxalate crystallization suggests that a combination of these 2 compounds may be highly useful as antilithiasis therapy.
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Oxalato de Calcio/antagonistas & inhibidores , Citratos/farmacología , Ácido Cítrico/farmacología , Magnesio/farmacología , Ácido Fítico/farmacología , Cristalización , Sinergismo Farmacológico , Microscopía Electrónica de Rastreo , OrinaRESUMEN
BACKGROUND: Diverse enzymatic and non-enzymatic antioxidants provide protection against reactive oxygen species in humans and other organisms. The nonenzymatic antioxidants include low molecular mass molecules such as plant-derived phenols. AIM OF STUDY: This study identified the major phenolic compounds of a grape seed extract by HPLC and analyzed the effect of consumption of biscuits enriched with this extract on the urinary oxidative status of healthy subjects by measurement of urine redox potential. METHODS: The major phenolic compounds were characterized in a red grape seed extract separated by HPLC with detection by a photodiode array (PDA), fluorescence (FL) and quadrupole mass spectrometer (MS). A nutritional study in a healthy volunteers group was done. Each volunteer ate eight traditional biscuits with no red grape seed extract supplementation. The second day each volunteer ate eight traditional biscuits supplemented with 0.6% (wt/wt) of grape seed extract. An overnight urine sample was obtained for each treatment. The redox potential was measured at 25 °C using a potentiometer in each urine sample. RESULTS: Epicatechin, catechin, procyanidin dimers B1 to B4, and the procyanidin trimer C2 were the major phenolic components in the extract. Epicatechin gallate and procyanidin dimers B1-3-G and B2-3'-G were the major galloylated flavan-3-ols. The forty-six healthy volunteers each shown a reduction of the urine redox potential after the treatment by traditional biscuits supplemented with the grape seed extract. CONCLUSIONS: This simple dietary intervention significantly reduced (33%) the urine redox potential, reflecting an overall increase in antioxidant status. Incorporation of plant-derived phenols in the diet may increase anti-oxidative status.
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Antioxidantes/administración & dosificación , Extracto de Semillas de Uva/administración & dosificación , Estrés Oxidativo/efectos de los fármacos , Fenoles/administración & dosificación , Vitis/química , Adolescente , Adulto , Biflavonoides/administración & dosificación , Biflavonoides/orina , Catequina/administración & dosificación , Catequina/análogos & derivados , Catequina/orina , Cromatografía Líquida de Alta Presión , Suplementos Dietéticos , Femenino , Voluntarios Sanos , Humanos , Masculino , Persona de Mediana Edad , Fenoles/orina , Proantocianidinas/administración & dosificación , Proantocianidinas/orina , Especies Reactivas de Oxígeno/metabolismo , Semillas/química , Adulto JovenRESUMEN
BACKGROUND: Improving knowledge about normal urine composition in children is important for early prevention of lithiasis. We describe urinary excretion values of calcium (Ca), magnesium (Mg), phosphate (P), citrate (Cit), uric acid (Ur), and oxalate (Ox) in healthy children with and without a family history of lithiasis, using a 12-h urine collection protocol. METHODS: Urine samples were obtained from 184 children (5-12 years): a spot sample collected in the afternoon, and a 12-h overnight sample. Solute/creatinine (Cr) and 12-h solute excretion was calculated. RESULTS: Urinary excretion values of the studied solutes are presented as percentile values, separately for each type of sample. Due to age-related differences in the solute/creatinine ratios, except for Ca and Cit, results are described according to the child's age. The presence of excretion values related to an increased risk of lithiasis was more common in children with a family history. CONCLUSIONS: We report data from urine samples collected by using a simplified collection protocol. The observed differences between children with and without a family history of lithiasis could justify that in population studies aimed at setting reference values, the former are excluded.
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Litiasis/orina , Calcio/orina , Niño , Preescolar , Ácido Cítrico/orina , Creatinina/orina , Femenino , Humanos , Litiasis/genética , Magnesio/orina , Masculino , Oxalatos/orina , Fosfatos/orina , Valores de Referencia , Ácido Úrico/orinaRESUMEN
OBJECTIVE: Although the incidence of urolithiasis is lower in children than in adults, the number of children with urolithiasis is increasing. Phytate, a naturally occurring compound present in legumes, nuts, and whole meals, has antilithiasic activity. The aim of this study was to assess, for the first time, the urinary levels of phytate in children and to correlate these levels with other urinary parameters related to crystallization risk and to general dietary habits. DESIGN AND METHODS: This was a cohort study conducted from April 2012 to March 2013 in the Laboratory of Investigation in Renal Lithiasis and at Son Espases Universitary Hospital in Palma de Majorca, Spain. SUBJECTS: Subjects included 165 healthy schoolchildren aged 5 to 12 years. INTERVENTION: All subjects followed their habitual diet. Information on the main dietary habits of the study subjects was obtained by asking each child's parents to fill out a dietary questionnaire. MAIN OUTCOME MEASURE: Phytate and citrate concentration and excretion were measured in 2 urine samples (a spot sample and a 12-hour overnight sample) for each child. Furthermore, common urinary biochemical indicators of stone risk were measured in each sample. RESULTS: The urinary phytate concentrations were low in this child population because of low consumption of dietary phytate. The urinary concentrations of phytate and citrate were low in 27.5% of these children. CONCLUSION: Because both substances are important inhibitors of crystallization, these finding suggests that these children are at risk of crystallization. Moreover, their diets consisted of foods rich in animal protein, with insufficient consumption of vegetables, legumes, and fruits.
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Nefrolitiasis/diagnóstico , Ácido Fítico/orina , Niño , Preescolar , Ácido Cítrico/orina , Estudios de Cohortes , Dieta , Conducta Alimentaria , Femenino , Humanos , Masculino , Nefrolitiasis/orina , Evaluación Nutricional , Factores de Riesgo , España , Encuestas y CuestionariosRESUMEN
Background: Crystallization experiments of renal-calculi-forming compounds (calcium oxalate, calcium phosphates, uric acid) are normally performed by monitoring these processes during periods of time similar to the residence of urine inside the kidney. Nevertheless, cystine requires high supersaturation for its crystallization, and most experiments last for longer periods. It must be considered that at high supersaturation, the inhibitors of crystalline development have poor effects. Methods: The induction time of crystallization (ti) of cystine in experimental conditions similar to those of the formation of cystine renal calculi and the effect of different cystine-binding thiol agents was determined through turbidimetric measurements. We also studied the macro- and microstructure of 30 cystine kidney stones through stereoscopic microscopy and scanning electron microscopy. Results: Under the studied conditions, the ti in absence of crystallization inhibitors was 15 min, and the presence of 9 mM of penicillamine, tiopronin, or N-acetylcysteine totally inhibited crystallization, as their effects relate to the formation of complexes with cystine, although N-acetylcysteine also delayed cystine crystalline development and modified cystine crystal morphology. Cystine stones have traditionally been classified as smooth and rough. The study of their structure shows that all of them begin their formation from a few crystals that generate a compact radial structure. Their subsequent growth, depending on the renal cavity where they are located, gives rise to the rough structure in the form of large blocks of cystine crystals or the smooth structure with small crystals. Conclusions: To prevent the development of cystine renal stones, the formation of small crystals must be avoided by reducing urinary cystine supersaturation, with N-acetylcysteine being the most effective among the studied cystine-binding thiol agents. Also, the removal of cystine crystals through increased water intake and physical activity can be a very important preventive measure.
RESUMEN
Background: Adults who have incomplete distal renal tubular acidosis (dRTA) may present with recurrent urolithiasis due to metabolic acidosis, leading to bone resorption, which in turn causes hypercalciuria and urine alkalinization (pH > 6.0). Oral potassium citrate is the most commonly used treatment for dRTA, but some patients cannot tolerate this treatment. The objective of this single-arm study was to evaluate the effect of phytate, an inhibitor of bone resorption, on calciuria of patients with incomplete dRTA. Methods: The calciuria levels of 16 patients who had incomplete dRTA with urolithiasis and could not tolerate potassium citrate treatment were recorded before (baseline) and after 6 months of treatment with oral calcium magnesium phytate (380 mg every 12 h). There were no dietary modifications or other treatments. Results: The baseline calciuria was 317 ± 81 mg/24 h and the level after 6 months was 221 ± 38 mg/24 h (p < 0.005). Conclusions: Our results suggest that calcium magnesium phytate should be considered as an alternative or adjunctive treatment for hypercalciuria in patients with incomplete dRTA.
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Type 2 diabetes mellitus has a worldwide prevalence of 10.5% in the adult population (20-79 years), and by 2045, the prevalence is expected to keep rising to one in eight adults living with diabetes. Mild cognitive impairment has a global prevalence of 19.7% in adults aged 50 years. Both conditions have shown a concerning increase in prevalence rates over the past 10 years, highlighting a growing public health challenge. Future forecasts indicate that the prevalence of dementia (no estimations done for individuals with mild cognitive impairment) is expected to nearly triple by 2050. Type 2 diabetes mellitus is a risk factor for the development of cognitive impairment, and such impairment increase the likelihood of poor glycemic/metabolic control. High phytate intake has been shown to be a protective factor against the development of cognitive impairment in observational studies. Diary phytate intake might reduce the micro- and macrovascular complications of patients with type 2 diabetes mellitus through different mechanisms. We describe the protocol of the first trial (the PHYND trial) that evaluate the effect of daily phytate supplementation over 56 weeks with a two-arm double-blind placebo-controlled study on the progression of mild cognitive impairment, cerebral iron deposition, and retinal involvement in patients with type 2 diabetes mellitus. Our hypothesis proposes that phytate, by inhibiting advanced glycation end product formation and chelating transition metals, will improve cognitive function and attenuate the progression from Mild Cognitive Impairment to dementia in individuals with type 2 diabetes mellitus and mild cognitive impairment. Additionally, we predict that phytate will reduce iron accumulation in the central nervous system, mitigate neurodegenerative changes in both the central nervous system and retina, and induce alterations in biochemical markers associated with neurodegeneration.
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Encéfalo , Disfunción Cognitiva , Diabetes Mellitus Tipo 2 , Retinopatía Diabética , Suplementos Dietéticos , Progresión de la Enfermedad , Hierro , Ácido Fítico , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Administración Oral , Encéfalo/metabolismo , Encéfalo/efectos de los fármacos , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/etiología , Disfunción Cognitiva/prevención & control , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/complicaciones , Retinopatía Diabética/metabolismo , Retinopatía Diabética/tratamiento farmacológico , Método Doble Ciego , Hierro/metabolismo , Hierro/administración & dosificación , Ácido Fítico/administración & dosificación , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
The effect of liver fibrosis on mild cognitive impairment (MCI) and dementia risk in type 2 diabetes mellitus (T2DM) patients is unclear. Therefore, we performed a prospective cross-sectional study on 219 patients with T2DM and older than 60 years to evaluate the association between liver fibrosis, liver steatosis, and cognitive impairment. The Montreal Cognitive Assessment (MoCA) was used to screen for MCI or dementia. Liver fibrosis was estimated using the non-invasive Fibrosis-4 (FIB-4) score, and liver steatosis was assessed with the hepatic steatosis index. The mean age was 71 ± 6 years, 47% were women and according to MoCA cut-off values, 53.88% had MCI and 16.43% had dementia. A moderate or high risk of advanced fibrosis was significantly higher in patients with MCI or dementia compared to those with normal cognition (p < 0.001). After adjusting for confounders, a FIB-4 score greater than 1.54 was associated with MCI or dementia (p = 0.039). Multivariate analysis identified age over 70.5 years, antiplatelet medication use, and a FIB-4 score above 1.54 as the most relevant risk factors. Liver fibrosis, but not liver steatosis, is associated with MCI or dementia in older T2DM patients, suggesting that FIB-4 score might be a simple biomarker for the detection of cognitive impairment.