Association of Adherence to The Mediterranean Diet with Urinary Factors Favoring Renal Lithiasis: Cross-Sectional Study of Overweight Individuals with Metabolic Syndrome.

Our purpose was to study the relationship of adherence to the Mediterranean diet (MedDiet) with urinary factors that favor the formation of renal calcium and uric acid stones in overweight and obese participants who had metabolic syndrome. This cross-sectional study examined 267 participants. A well-known MedDiet score (range 0-9) was calculated for each patient, and patients were then categorized has having low (≤3), medium (4-5), or high (≥6) adherence to the MedDiet. Baseline characteristics and urinary parameters were also analyzed. High calcium salt urinary crystallization risk (CaUCR) and high uric acid urinary crystallization risk (UrUCR) were calculated from urinary parameters using pre-defined criteria. More than half of patients with MedDiet scores ≤3 had high UrUCR (55.4%) and high CaUCR (53.8%). In contrast, fewer patients with high adherence (≥6) to the MedDiet had high UrUCR (41.2%) and high CaUCR (29.4%). Relative to those with low adherence, individuals with high adherence had a prevalence ratio (PR) of 0.77 for a high UrUCR (95% CI: 0.46-1.12; p for trend: 0.069) and a PR of 0.51 for a high CaUCR (95% CI: 0.26-0.87; p for trend: 0.012) after adjusting for age, sex, body mass index, type 2 diabetes, and total energy intake. Our findings indicate that greater adherence to the MedDiet was associated with a reduced CaUCR and a reduced UrUCR. This suggests that adequate dietary management using the MedDiet patterns may prevent or reduce the incidence and recurrence of calcium salt and uric acid renal stones.

Impaired Liver Size and Compromised Neurobehavioral Activity are Elicited by Chitosan Nanoparticles in the Zebrafish Embryo Model.

The use of chitosan nanoparticles (ChNPs) in various biological and environmental applications is attracting great interest. However, potential side effects related to ChNP toxicity remain the major limitation hampering their wide application. For the first time, we investigate the potential organ-specific (cardiac, hepatic, and neuromuscular) toxicity of ChNPs (size 100⁻150 nm) using the zebrafish embryo model. Our data highlight the absence of both acute and teratogenic toxic effects of ChNPs (~100% survival rate) even at the higher concentration employed (200 mg/L). Although no single sign of cardiotoxicity was observed upon exposure to 200 mg/L of ChNPs, as judged by heartbeat rate, the corrected QT interval (QTc, which measures the time between the start of the Q wave and the end of the T wave in the heart's electrical cycle), maximum cardiac arrest, and ejection fraction assays, the same dosage elicited the impairment of both liver size (decreased liver size, but without steatosis and lipid yolk retention) and neurobehavioral activity (increased movement under different light conditions). Although the observed toxic effect failed to affect embryo survival, whether a prolonged ChNP treatment may induce other potentially harmful effects remains to be elucidated. By reporting new insights on their organ-specific toxicity, our results add novel and useful information into the available data concerning the in vivo effect of ChNPs.

Effect of Consumption of Cocoa-Derived Products on Uric Acid Crystallization in Urine of Healthy Volunteers.

The purpose of this study was to determine the effects of consumption of different cocoa-derived products on uric acid crystallization in urine of 20 healthy volunteers. Participants were requested to select the specific diet that they wished to follow during the 12 h prior to collection of urine. The only restriction was that the diet could not include any product with cocoa, coffee, or caffeine. On the first day, each volunteer followed their selected diet, and an overnight 12 h urine sample was collected as the baseline urine. After seven days on an unrestricted diet, each volunteer repeated the same diet with 20 g of milk chocolate, chocolate powder, or dark chocolate during breakfast and another 20 g during dinner. Overnight 12 h urine samples were then collected. Urine volume, pH, oxalate, creatinine, uric acid, theobromine, and a uric acid crystallization test were determined for each sample. The results for all 20 patients show that uric acid crystallization was significantly lower following the consumption of chocolate powder or dark chocolate relative to baseline or following the consumption of milk chocolate. The results indicated that increased concentrations of urinary theobromine reduced the risk of uric acid crystallization.

[May renal lithiasis be really prevented? New trends and therapeutic tools.] / Se puede realmente prevenir la litiasis renal? Nuevas tendencias y herramientas terapéuticas.

Renal calculi are generally formed as a result of the combination of certain factors, some related to urine composition (concentration of lithogenic substances, deficiency of crystallization inhibitors, presence of heterogeneous nucleants) and others with renal morphology and anatomy (urinary tract stasis, low urodynamic efficiency cavities, morpho-anatomic deformations, renal papillary tissue lesions). In fact, the composition, macrostructure and microstructure of the calculus will clearly depend on the factors that have induced it. For this reason, the appropriate study and classification of the renal calculi simplifies the diagnosis and allows a more effective therapeutic approach since it can be oriented to directly correct the etiological factors responsible for stone formation. In this article, we review the main etiological factors involved in the formation of each type of calculus and the prophylactic measures that can be adopted for proper correction. The most frequent kidney stones have been classified into the following types: calcium oxalate monohydrate papillary calculi, calcium oxalate monohydrate non-papillary calculi, calcium oxalate dihydrate calculi, mixed hydroxyapatite/ calcium oxalate calculi, carboxyapatite/hydroxyapatite calculi, brushite calculi, struvite/carboxyapatite calculi, uric acid calculi, uric acid/calcium oxalate monohydrate calculi, and cystine calculi. Occasionally, however, the calculus is not available for study, in which case the only way forward is to use all available information (clinical history, life habits, radiological data), together with basic biochemical information, to identify and correct all etiological factors related to renal lithiasis that have been identified.

¿Se puede realmente prevenir la litiasis renal? Nuevas tendencias y Herramientas terapéuticas / May renal lithiasis be really prevented? New trends and therapeutic tools

Los cálculos renales se forman en general como consecuencia de la combinación de determinados factores, algunos relacionados con la composición de la orina (concentración de sustancias litógenas, déficit de inhibidores de la cristalización, presencia de nucleantes heterogéneos) y otros con la morfoanatomía renal (estasis urinaria, cavidades de baja eficacia urodinámica, deformaciones morfoanatómicas, lesiones del tejido papilar renal). De hecho, la composición, macroestructura y microestructura del cálculo dependerán claramente de los factores que lo han inducido. Por esta razón, disponer del cálculo renal convenientemente estudiado y clasificado simplifica el diagnóstico y posibilita un enfoque terapéutico más eficaz ya que se dirige directamente a corregir los factores etiológicos responsables de la litiasis. En esta publicación revisamos los principales factores etiológicos implicados en la formación de cada tipo de cálculo y las medidas profilácticas que pueden adoptarse para su adecuada corrección. Los cálculos renales más frecuentes se han clasificado en los siguientes tipos: cálculos de oxalato cálcico monohidrato papilares, cálculos de oxalato cálcico monohidrato de cavidad, cálculos de oxalato cálcico dihidrato, cálculos mixtos de hidroxiapatita/oxalato cálcico, cálculos de carboxiapatita/hidroxiapatita, cálculos de brushita, cálculos de estruvita/carboxiapatita, cálculos de ácido úrico, cálculos de ácido úrico/oxalato cálcico monohidrato y cálculos de cistina. En ocasiones, sin embargo, no se dispone del cálculo para su estudio, en cuyo caso el único camino a seguir consiste en utilizar toda la información disponible (historial clínico, hábitos de vida, datos radiológicos), junto con la información bioquímica urinaria básica, para identificar y corregir cuantos factores etiológicos relacionados con la litiasis renal se hayan identificado

Renal calculi are generally formed as a result of the combination of certain factors, some related to urine composition (concentration of lithogenic substances, deficiency of crystallization inhibitors, presence of heterogeneous nucleants) and others with renal morphology and anatomy (urinary tract stasis, low urodynamic efficiency cavities, morpho-anatomic deformations, renal papillary tissue lesions). In fact, the composition, macrostructure and microstructure of the calculus will clearly depend on the factors that have induced it. For this reason, the appropriate study and classification of the renal calculi simplifies the diagnosis and allows a more effective therapeutic approach since it can be oriented to directly correct the etiological factors responsible for stone formation. In this article, we review the main etiological factors involved in the formation of each type of calculus and the prophylactic measures that can be adopted for proper correction. The most frequent kidney stones have been classified into the following types: calcium oxalate monohydrate papillary calculi, calcium oxalate monohydrate non-papillary calculi, calcium oxalate dihydrate calculi, mixed hydroxyapatite/ calcium oxalate calculi, carboxyapatite/hydroxyapatite calculi, brushite calculi, struvite/carboxyapatite calculi, uric acid calculi, uric acid/calcium oxalate monohydrate calculi, and cystine calculi. Occasionally, however, the calculus is not available for study, in which case the only way forward is to use all available information (clinical history, life habits, radiological data), together with basic biochemical information, to identify and correct all etiological factors related to renal lithiasis that have been identified

Phytotherapy in a rat model of hyperoxaluria: the antioxidant effects of quercetin involve serum paraoxonase 1 activation.

Serum paraoxonase 1 (PON1) has been reported to be an important contributor to the antioxidant and anti-inflammatory activities of HDL, avoiding LDL oxidation. The activity of this enzyme is reduced in patients with renal insufficiency, caused by elevated oxidative stress and disturbances of apolipoprotein metabolism. Therapeutic utilization of antioxidants to control renal oxidative stress may be an effective therapy in renal protection. The aim was to investigate the protective effects of several antioxidant compounds against the oxidative stress associated to renal failure induced by ethylene glycol (EG), focusing on the possible role of serum PON1 activity. Fifty-four male Wistar rats were randomly assigned to six groups (n = 9): an untreated control (C) group, an EG-treated group, a catechin (CAT)-treated group, an epicatechin (EPI)-treated group, a quercetin (QUE)-treated group and a folk herbal extract (FHE)-treated group. After 16 d of treatment, calcium oxalate lithiasis was induced in the rats using EG. After eight days (treatment + EG), the animals were sacrificed. EG treatment impaired kidney composition, increased oxidative damage, and decreased serum paraoxonase and arylesterase activities. CAT, QUE and the FHE Fagolitos improved oxidative status by enhancing antioxidant defenses - superoxide dismutase and PON1 activities - and reducing oxidative damage, thus reinforcing the idea of a possible role of PON1 in the protective effects of QUE against the deleterious consequences of oxidative stress in kidney.

Non-infectious phosphate renal calculi: fine structure, chemical and phase composition.

BACKGROUND: Chemical composition of internally non-homogeneous phosphate stones should be related to the conditions prevailing during the formation of each individual part. OBJECTIVE: The object of this paper was to provide a detailed study of phosphate stone composition on the micro- and macro-scales. METHODS: Fine inner structure, chemical and phase composition of 10 phosphate calculi from different patients were determined by chemical (wet) analysis, observation by scanning microscope, semi-quantitative determination of Ca, Mg, P and C by energy dispersive X-ray and by X-ray diffraction. Results. Eight calculi are formed by amorphous calcium phosphate and two by hydroxyapatite. Magnesium was inversely related to Ca/P ratio. Point chemical composition of solid phase varies in wide limits, i.e. composition of calculus interior is highly inhomogeneous on the microscale. All studied calculi contained an abundance of organic matter incorporated in their volume; the content of carbon was double the calcium content in molar quantities. CONCLUSIONS: Phosphate renal calculi with the low Ca/P molar ratio predominantly consist of amorphous calcium phosphate whereas those with a high Ca/P molar ratio are composed of poorly crystalline hydroxyapatite which can be partially carbonated. Magnesium may be an inhibitor of HAP formation from urine. Abundant organic matter incorporated into the calculus volume indicates its decisive role at stone formation. Variable point composition of stones implies widely varying conditions during their development.

Rare calcium oxalate monohydrate calculus attached to the wall of the renal pelvis.

Most renal calculi can be classified using well-established criteria in a manner that reflects both composition and fine structure under specific pathophysiological conditions. However, when a large patient population is considered, rare renal calculi invariably appear, some of which have never been classified; careful study is required to establish stone etiology in such cases. The patient in the present case report formed two types of calculi. One was attached on the wall of the renal pelvis near the ureter and part of the calculus was embedded inside pelvic renal tissue. The calculus developed on an ossified calcification located in the pelvis tissue. Current knowledge on the development of calcification in soft tissues suggests a pre-existing injury as an inducer of its development. A mechanism of calculus formation is proposed. The second stone was a typical jack-stone calculus.

Effect of tetracalcium dimagnesium phytate on bone characteristics in ovariectomized rats.

The aim was to evaluate the influence of dietary Ca-Mg-phytate consumption on the bone characteristics of ovariectomized rats, an animal model for postmenopausal osteoporosis. Twenty ovariectomized female Wistar rats were randomly assigned to two groups fed, respectively, with a non-phytate diet (AIN-76A) or the same diet enriched with 1% phytate (as the calcium magnesium salt, phytin). After 12 weeks of feeding the rats were sacrificed, and both femoral bones and L4 vertebra were removed from each rat. Bone mass, length, width, volume, and mineral density were measured, and the phosphorus, calcium, magnesium, and zinc contents of bones were determined. Deoxypyridinoline (a bone resorption marker) was measured in urine, and osteocalcin (a bone formation marker) was measured in serum. The calcium and phosphorus contents and bone mineral density were significantly higher in both femoral bones and L4 vertebra for phytate-treated rats in comparison to rats in the non-phytate group. Deoxypyridinoline was significantly increased in rats in the non-phytate treatment group. Ca-Mg-phytate consumption reduces bone mineral density loss due to estrogen deficiency. Thus, phytate exhibits effects similar to those of bisphosphonates on bone resorption and may be of use in the primary prevention of osteoporosis if larger studies in humans confirm these findings.

Effects of Mediterranean diets with low and high proportions of phytate-rich foods on the urinary phytate excretion.

BACKGROUND: Important health benefits have been reported recently to phytate intake. This includes the prevention of pathological calcifications such as renal calculi, dental calculi and cardiovascular calcification, due its action as crystallization inhibitor of calcium salts, and as preventive of cancer. AIM OF STUDY: The aim of this study was to establish a relation between the intake of phytate, through consumption of typical components of the Mediterranean diet (including nuts), and its excretion in urine. METHODS: This study recruited participants from subjects included in a larger trial (PREDIMED) of food habits, that were assigned to one of two diet groups: (1) the Mediterranean diet with low proportion of phytate-rich food group, where participants were asked to maintain their usual diet; and (2) the Mediterranean diet with high proportion of phytate-rich food group, where participants were asked to increase phytate-rich foods in their diet. Phytate intake was assessed on the basis of a food frequency questionnaire. Urinary phytate excretion was determined in 2-h urine samples. RESULTS: The overall phytate consumption of the Mediterranean diet with high proportion of phytate-rich food group (672 +/- 50 mg) was significantly higher than the Mediterranean diet with low proportion of phytate-rich food group (422 +/- 34 mg), representing a 59% difference. Urinary phytate excretion was also significantly higher (54%) in the Mediterranean diet with high proportion of phytate-rich food group (1,016 +/- 70 microg/L) than the Mediterranean diet with low proportion of phytate-rich food group (659 +/- 45 microg/L). CONCLUSIONS: Mediterranean diets high in whole cereals, legumes and nuts compared to Mediterranean diets low in these phytate-rich foods increase the urinary phytate excretion in humans.

A potential role for crystallization inhibitors in treatment of Alzheimer's disease.

Melatonin is a hormone synthesized from the neurotransmitter serotonin and is found mainly in the pineal gland. Melatonin has been suggested to have several properties, acting both as an antioxidant and a neuroprotective agent. Melatonin synthesis decreases with age in all humans, but this decline is more pronounced in Alzheimer's patients. In fact, melatonin inhibits the formation of beta-amyloid protein. The mechanism responsible for this decline has not been fully elucidated, although it is known that the human pineal gland calcifies with age. Such calcification necessarily implies the existence of a tissue injury that, if not reabsorbed by the immune system, will act as heterogeneous nucleant for hydroxyapatite and will induce calcification. For this reason, it is hypothesized that a lack of inhibitors of calcium salt crystallization, such as pyrophosphate and phytate, will favor calcification. Therefore, the absence of crystallization inhibitors may be a risk factor for development of Alzheimer's disease, and this hypothesis should be evaluated.

Phytotherapy and renal stones: the role of antioxidants. A pilot study in Wistar rats.

Since ancient times, various herbal preparations have been used in renal lithiasis therapy, but conclusive scientific data on their therapeutic effects and efficacy are not available. To address this issue, the present study evaluated the antilithiasic activity of a traditional Mallorcan herbal preparation, and compared its effects with those of the antioxidant flavonoids, catechin and epicatechin. Thirty-six male Wistar rats were assigned randomly to four groups (n = 9): a control group, a catechin (CAT) treatment group, an epicatechin (EPI) treatment group, and a group treated with a folk herbal extract (FHE). After 16 days of treatment, calcium oxalate lithiasis was induced in the rats using ethylene glycol. After 8 days (treatment + ethylene glycol), 24-h rat urine was collected, the animals were sacrificed and their kidneys were removed for histological and chemical analysis. The calcium concentration in kidney tissue was significantly lower in the CAT-treated (2.4 +/- 0.3 mg/g), EPI-treated (1.8 +/- 0.3 mg/g) and FHE-treated (2.1 +/- 0.3 mg/g) groups, than in the control group (5.4 +/- 1.4 mg/g). Examination of paraffin-embedded kidney sections showed that control group rats had the greatest amount of calcification. There were no significant differences between control and treated groups with respect to urinary calcium, magnesium, oxalate and citrate concentrations. These results demonstrate the ability of herbal preparations and antioxidants to prevent the development of papillary and intratubular calcification in the kidney.

Role of phytate and osteopontin in the mechanism of soft tissue calcification.

BACKGROUND: Understanding the mechanism of calcium deposition in soft tissues is of great importance in a variety of pathological conditions such as chronic kidney disease. The present study examined the role of phytate and osteopontin during the development of soft tissue calcification in an animal model. METHODS: Male Wistar rats (16 rats per treatment) were fed with a diet (AIN-76A) in which phytate is undetectable (non-phytate-treated group), or with a phytin-enriched AIN-76A diet (phytate-treated group). After 21 days on the respective diets, all rats were subjected to calcinosis induction by subcutaneous injection with KMnO4 at 2 sites on either side of the interscapular region. At 2, 5, 8 and 10 days after the calcinosis induction, 4 rats of each group were sacrificed, and the injured tissues were removed for histological analysis and for calcium determination. RESULTS: Calcification was notably and significantly reduced in phytate-treated rats compared with non-phytate-treated rats. Calcified deposits appeared as soon as 2 days after calcinosis induction, but inflammation with the presence of macrophages, lymphocytes and eosinophils was not typically observed until 5 days postinduction. Osteopontin was only detected 8 days postinduction, and was clearly associated with calcified areas. CONCLUSIONS: The results suggest an important role for crystallization inhibitors such as phytate in reducing hydroxyapatite crystal formation in the first steps of soft tissue calcification. Histological analysis indicated that osteopontin was not involved during initiation of soft tissue calcification. Osteopontin appears be involved in the control of calcification rather than its genesis.

Phytate inhibits bovine pericardium calcification in vitro.

OBJECTIVE: The present study examined the inhibitory effects of pyrophosphate, etidronate, and phytate on bovine pericardium calcification in vitro. METHODS: Bovine pericardium was glutaraldehyde fixed and then placed in a flow chamber in the presence of a synthetic physiological fluid alone (control) or the fluid plus various concentrations of pyrophosphate, etidronate, or phytate. Following a 96-h incubation, fragments were removed and assayed for calcification by measuring calcium and phosphorus levels. RESULTS: The data indicated that both pyrophosphate and etidronate at 1 mg/l (5.75 and 4.95 microM, respectively) inhibited bovine pericardium calcification, whereas neither agent had an effect at 0.5 mg/l (2.87 and 2.47 microM, respectively). Phytate was the most potent inhibitor of calcification, and the effects of this agent were apparent at levels as low as 0.25 mg/l (0.39 microM). CONCLUSIONS: While pyrophosphate, etidronate, and phytate were all able to inhibit bovine pericardium calcification in vitro, phytate was found to be the most effective.

Effects of exogenous inositol hexakisphosphate (InsP(6)) on the levels of InsP(6) and of inositol trisphosphate (InsP(3)) in malignant cells, tissues and biological fluids.

InsP(6) is abundant in cereals and legumes. InsP(6) and lower inositol phosphates, in particular InsP(3), participate in important intracellular processes. In addition, InsP(6) possess significant health benefits, such as anti-cancer effect, kidney stones prevention, lowering serum cholesterol. Because of the insensitivity of existing methods for determination of non-radiolabeled inositol phosphates, little is known about the natural occurrence, much less on the concentrations of InsP(6) and InsP(3) in biological samples. Using gas chromatography-mass detection analysis of HPLC chromatographic fractions, we report a measurement of unlabeled total InsP(3) and InsP(6) (a) as they occur within cells culture, tissues, and plasma, and (b) their changes depending on the presence of exogenous InsP(6). When rats were fed on a purified diet in which InsP(6) was undetectable (AIN-76A) the levels of InsP(6) in brain were 3.35 +/- 0.57 (SE) micromol.kg(-1) and in plasma 0.023 +/- 0.008 (SE) micromol.l(-1). The presence of InsP(6) in diet dramatically influenced its levels in brain and in plasma. When rats were given an InsP(6)-sufficient diet (AIN-76A + 1% InsP(6)), the levels of InsP(6) were about 100-fold higher in brain tissues (36.8 +/- 1.8 (SE)) than in plasma (0.29 +/- 0.02 (SE)); InsP(6) concentrations were 8.5-fold higher than total InsP(3) concentrations in either plasma (0.033 +/- 0.012 (SE)) and brain (4.21 +/- 0.55 (SE)). When animals were given an InsP(6)-poor diet (AIN-76A only), there was a 90% decrease in InsP(6) content in both brain tissue and plasma (p < 0.001); however, there was no change in the level of total InsP(3). In non-stimulated malignant cells (MDA-MB 231 and K562) the InsP(6) contents were 16.2 +/- 9.1 (SE) micromol.kg(-1) for MDA-MB 231 cells and 15.6 +/- 2.7 (SE) for K 562 cells. These values were around 3-fold higher than those of InsP(3) (4.8 +/- 0.5 micromol.kg(-1) and 6.9 +/- 0.1 (SE) for MDA-MB 231 and K562 cells respectively). Treatment of malignant cells with InsP(6) resulted in a 2-fold increase in the intracellular concentrations of total InsP(3) (9.5 +/- 1.3 (SE) and 10.8 +/- 1.0 (SE) micromol.kg(-1) for MDA-MB 231 and K562 cells respectively, p < 0.05), without changes in InsP(6) levels. These results indicate that exogenous InsP(6) directly affects its physiological levels in plasma and brain of normal rats without changes on the total InsP(3) levels. Although a similar fluctuation of InsP(6) concentration was not seen in human malignant cell lines following InsP(6) treatment, an increased intracellular levels of total InsP(3) was clearly observed.