Calcium Oxalate Lithiasis Research Articles

Promising Natural Approach: Caesalpinia bonduc Seed Extracts for Calcium Oxalate Urolithiasis in Rats

Background: It is essential to identify a therapy for hyperoxaluria that specifically focuses on reducing oxalate excretion since current therapies for urolithiasis have drawbacks. It is noteworthy to observe that the seeds of Caesalpinia bonduc (Family: Caesalpiniaceae) have been historically used by several Indian tribes for the purpose of treating renal diseases. Purpose: The primary purpose of this study was to assess the efficacy of C. bonduc seed extracts as therapeutic agents in rats with experimentally generated calcium oxalate urolithiasis. Methodology: The experimental animals were given 0.75% of ethylene glycol orally for fourteen consecutive days in order to produce calcium oxalate lithiasis. C. bonduc seed extracts, 400 mg/kg of body weight in aqueous and ethanolic forms, were administered in the same way for a further 14 days in succession. The standard antiurolithiatic medicine used was cystone, administered at a dose of 750 mg/kg of body weight. The research primarily examined the quantification of serum biochemical markers and the elimination of salt constituents from urine and renal deposits, which were shown to be challenging. Results: Ethylene glycol administered orally caused hyperoxaluria and augmented calcium, phosphate, and oxalate excretion in the kidneys. Nevertheless, the administration of C. bonduc seed extracts effectively decreased the elevated levels of oxalate in the urine, showing an inhibitory effect on the synthesis of oxalate inside the human body. The renal accumulation of components that cause stone formation in rats with calculogenic conditions decreased considerably after the administration of curative treatments with aqueous and ethanolic extracts. Discussion and Conclusion: Based on the findings, it has been shown that C. bonduc seeds have lithontriptic action, which deserves further investigation as a potential remedy for urolithiasis. Further research is necessary to elucidate the specific phytoconstituents present in seeds that are responsible for their antiurolithiatic activity.

#2827 Beyond the scale: unveiling the kidney stone risk after bariatric surgery

Abstract Background and Aims Nephrolithiasis is a prevalent condition, with calcium oxalate being the primary component found in kidney stones. Both obesity and gastric bypass surgery pose as risk factors for nephrolithiasis. Malabsorptive bariatric procedures alter 24-hour urine profiles, leading to increased urinary oxalate and reduced urinary citrate levels. This study aims to evaluate the risk factors for calcium oxalate lithiasis in a population after gastric bypass surgery at our center. Method We performed a monocentric retrospective study to evaluate hyperoxaluria and urinary lithiasis in patients who underwent gastric bypass surgery between 2020 and 2021. We assessed urinary oxalate excretion, urinary citrate excretion, and urinary sodium excretion between 4 and 28 months after surgery. To confirm the adequacy of the collection, a comparison was made with the expected urinary creatinine value (20 to 25 mg/kg ideal weight for men and 15 to 20 mg/kg ideal weight for women). We developed a risk score: citraturia < 288 mg/24 h (1 point); oxaluria > 45 mg/L (1 point) and natriuresis > 97.75 mmol/24 h (1 point). Patients were classified as without risk (0 points), at low risk (1 point), at high risk (2 points), and at very high risk (3 points). Additionally, the patients’ historical incidence of lithiasis was examined, both preoperatively and postoperatively, using clinical records. Post-surgery assessments included imaging evidence of lithiasis (when available) or clinical episodes of renal colic. Results Fifty-six patients underwent a 24-hour urine collection. Twenty-two were excluded due to incomplete urine collection, determined by the expected urinary creatinine value and a time lapse exceeding 28 months between surgery and analytical assessment. The median time elapsed between surgery and analytical evaluation was 9.5 months [IQR 6.3 - 12] months. A total of 34 patients were included in the study, 8.8% were male and the median age of the patients was 51.5 [IQR 42.3–57.8] years. The median body mass index decreased from 43.1 [IQR 39.7–46.3] kg/m2 before to 31.8 [IQR 28.6–35.7] kg/m2 six months after surgery. The low risk for calcium oxalate lithiasis in the examined patient sample was 52.9% (n = 18); high risk 20.6% (n = 7), no risk 26.5% (n = 9) and very high risk 0%. We detected 3 (8.8%) patients with concentration hyperoxaluria, 20 (58.8%) patients with natriuresis > 97.75 mmol/24 h and 8 (23.5%) patients with reduced urinary citrate levels. All patients exhibited normal kidney function. The median follow-up duration was 27 months. Out of the total number of patients, only 3 reported renal colic episodes, and imaging evidence of lithiasis was found in just 2 of them before surgery. Among those with a risk score > 0, only 1 had a history of lithiasis. Throughout the follow-up period, none of the patients experienced new lithiasis post-surgery. Regarding the limitations of our study, we highlight the relatively brief duration of follow-up, which may pose challenges in comprehensively evaluating outcomes such as lithiasis. Additionally, the absence of imaging screening represents a notable constraint, impeding the comprehensive assessment of patients with asymptomatic lithiasis. Conclusion This study concludes that within the bariatric surgery population, a specific subgroup is at an elevated risk for renal lithiasis. Recognizing this subgroup promptly and instituting heightened preventive measures may prove advantageous within this demographic.

In vivo Anti-lithiasis activity and antibacterial effect of hydroalcoholic extract and infusion of Punica granatum L. peel.

ObjectiveUrolithiasis disease is a severe pathology causing painful bleeding in patients and can lead to kidney failure. Current treatments are limited, expensive, invasive with side effects and requires new alternatives, especially those based on natural products. This work aimed to determine the in vivo antilithiasis effect of hydroalcoholic extract (E.PG) and infusion (I.PG) of the Punica granatum L. plant, as well as their antibacterial capacity against the strains responsible of urinary tract infection such as: E. coli, P. Mirabilis, K. pneumoniae and S. Aureus. MethodsA curative protocol was followed, which consisted of inducing calcium oxalate lithiasis in rats by ethylene glycol (75%) and ammonium chloride (1%) solutions. After 15 days of oxalocalcic lithiasis induction, plant extracts were administered to rats at two different doses (200 and 400 mg/kg/day), with potassium citrate (Cit.K) used as a positive control. Water intake, urine volume, pH and body weight were measured with crystalluria and histopathological examinations of the kidneys performed. The antibacterial activity was studied by the disk diffusion method and the minimum inhibitory concentration (MIC) method. The checkerboard technique was used to determine the interactions between the two extracts. ResultsThe results found show a significant effectiveness of the Punica granatum L. extracts, especially the infusion in preventing the formation, development and calcium oxalate crystals deposition. In fact, crystalluria revealed an important diuresis with the presence of a very low crystals number (<50 / mm3) of very small size in the rat's urine treated with EPG and IPG at the concentration of 400 mg/kg/day. Kidney histopathology analysis showed the absence of crystal deposition, as well as an almost normal structure. Moreover, the antimicrobial activity showed the efficiency of the plant extracts in inhibiting the growth of P. mirabilis and S. aureus where the inhibition zones (IZ) revealed by the disk diffusion method are between 14 and 16 mm. I.PG extract displayed a very low MIC of 1.875 against E. coli. Furthermore, the interaction between these two extracts showed partial synergy and an additive effect against S. Aureus and K. pneumoniae. ConclusionsPunica granatum L. plant has promising antilithiasis and antibacterial effects. Therefore, future extensive studies are needed to establish its effectiveness for clinical use.

The Inhibitory Ability of Orobanche Extract on Calcium Oxalate Lithiasis in Male Albino Rats

The present study aimed to evaluate the inhibitory effect of Orobanche extract in ethylene glycol induced nephrolithiasis. Thirty male albino rats were divided into five groups each group contains 6 animals, group (1) control group, group (2) animals were supplied with 0.75% ethylene glycol in drinking water, group (3) animals were administrated Orobanche extract 3g/kg orally, group (4) animals were administrated Cystone 500 mg/kg in addition to 0.75% ethylene glycol, group (5) animals were administrated Orobanche extract 3g/kg orally in addition to 0.75% ethylene glycol the experiment continued for 28 days. Serum and the kidney homogenates were analyzed for various biochemical parameters and urine was examined microscopically for crystals. Orobanche treatment group and Cystone treatment group significantly decreased phosphorus, Calcium and Oxalate in kidney tissue of nephrolithiasis rats and significantly decreased kidney and liver marker in serum of nephrolithiasis rats. Conclusion this result revealed that Orobanche extract could be a potential candidate for phytotherapy against nephrolithiasis.

Biochemical, Pharmacological, and Therapeutic Effects of Triple Antihypertensive Therapy with Amlodipine, Valsartan and Hydrochlorothiazide in Elderly Hypertensive Patients with Calcium Phosphate Nephrolithiasis

Antihypertensives are widely prescribed in the geriatric population and could influence kidney stone risk but many aspects are still unknown. Thiazides are used to control lithogenic factors and recurrences in patients with calcium lithiasis. The aim of our study was to evaluate the relationship between essential arterial hypertension and stone disease, by studying the pharmaco-therapeutic effects of a fixed-dose combination of amlodipine + valsartan + hydrochlorothiazide (Aml + Val + HCTZ) 10/320/25 mg, on the urinary stone risk in a study group of hypertensive geriatric patients. A longitudinal, randomized, three years follow-up clinical and experimental study was conducted during June 1, 2014 - July 31, 2017. A number of 60 eligible geriatric patients, treated only with a fixed-dose combination of Aml + Val + HCTZ 10/320/25 mg, as a single-tablet, were enrolled in the study. All the patients were stone formers, with more than three episodes of crystalluria in the last two years. The patient�s age ranged between 55 and 65 years. Exclusion criteria: patients with heart failure, kidney chronic diseases, use of drugs known to affect renal function, patients with multi-morbidities. All patients had similar blood pressure values, and tension was well controlled throughout the whole study period. In the elderly patients, the treatment with 25 mg/day of hydrochlorothiazide (from the combination of Aml + Val + HCTZ 10/320/25 mg) has a beneficial and prolonged efficacy in treatment of recurrences in patients with calcium oxalate and phosphate lithiasis Our study reveals that in the elderly patients with hypertension and nephrolithiasis as a comorbidity, thiazides - 25 mg/day of hydrochlorothiazide (from the combination of Aml + Val + HCTZ 10/320/25 mg) has a beneficial effect in order to control lithogenic factors and recurrences in patients with calcium phosphate lithiasis.

Recherche de facteurs lithogènes au cours des lithiases oxalo-calciques : enquête épidémiologique

Calcium oxalate stones are the most common urolithiasis. Changes in dietary habits, socio-economic and health status of populations explain its progression. The aim of our study was to determine metabolic factors leading to lithiasis and clarify its causes. This is a retrospective study of 100patients with calcium oxalate stones identified by morpho-constitutional study, collected in our department over a period of 5years (2008-2013). We analyzed clinical, radiological and metabolic data. They were 73men and 27women (gender ratio: 2.7), aged meanly of 44.8years. Dietary survey revealed inadequate calcium intake in 87% of cases. Urinary abnormalities were hypocitraturia (34%), hypomagnesuria (32%) and outflow hypercalciuria (21%). Crystalluria was positive in 44% of cases. Whewellite was the most common crystalline form. Calculi were bilateral (53%), renal (85%) and mainly collected after urological procedures (74%). Infrared analysis showed that 81% of stones have a heterogeneous composition. Pure Whewellite or combined with other compounds was the most frequent (31%). Idiopathic calcium oxalate lithiasis was the most common etiology (69%). Among secondary etiologies, diabetes was most frequently found (10%). Our epidemiological study of calcium oxalate stones has allowed us to identify the high frequency of food hyperoxaluria partly explained by a low calcium intake and a diet rich in oxalate phytotherapy. 4.

Arginine as a Significant Regulator of Supersaturation in Calcium Oxalate Lithiasis: the Physiological Evidence

Background: At present, the possible effect of arginine as a natural regulator of calcium oxalate (CaOX) supersaturation and crystallization in human urine has been analyzed. Methods: Two types of experiments have been discussed: clinical laboratory analysis on the urine excretion of arginine (Arg) in patients with CaOX lithiasis and detailed measurements of the kinetics of the dissolution of CaOX calculi in artificial urine, containing various concentrations of Arg. Results: A detailed analysis showed that 80% of stone formers (SFs) eliminated pathological values: 30% of patients had lower plasma levels compared to controls and about 50% of SFs showed higher concentration. Urine concentrations in these two groups were not reported. Conclusions: The in vitro analytical measurements demonstrate even a possibility to dissolve CaOX stones in human urine, in which increased concentration of Arg has been established. Discussions have arisen to use increased concentration of Arg in urine both as a solubilizator of CaOX stones in humans and on the purpose of a prolonged metaphylactic treatment. World J Nephrol Urol. 2015;4(1):173-177 doi: http://dx.doi.org/10.14740/wjnu199w

On the origin of calcium oxalate monohydrate papillary renal stones.

Calcium oxalate monohydrate (COM) papillary calculi can be initiated by subepithelial calcification of the renal papillae. Hydroxyapatite disruption of the papillary epithelial layer can become the nidus of a COM papillary calculus. This study evaluated the causes of papillary tissue calcifications in 60 patients with calcium oxalate lithiasis, 30 with COM papillary and 30 with calcium oxalate dihydrate (COD) calculi. Urinary redox potential was higher in the COM than the COD group, suggesting that the former is more deficient in antioxidants due to increased oxidative stress. Urinary calcium was significantly higher in the COD group, whereas urinary oxalate was significantly higher in the COM group, suggesting a greater degree of oxidative injury of renal cells. Evaluations of their diets showed that both groups consumed low amounts of phytate-rich products. Of chronic diseases possibly associated with urolithiasis, only the prevalence of gastroduodenal ulcer differed significantly, being higher in the COM group and suggesting that epithelial lesions are common to gastroduodenal ulcers and COM papillary renal stones. Occupational exposure to cytotoxic products occurred in 47 % of the COM and 27 % of the COD group, but this difference was not statistically significant. These findings indicate that oxidative stress is associated with injury to papillary tissue and that this is the origin of intrapapillary calcifications. The continuation of this process is due to modulators and/or deficiencies in inhibitors of crystallization. Identifying and eliminating the causes of injury may prevent recurrent episodes in patients with papillary COM calculi.

Dietary hydroxyproline induced calcium oxalate lithiasis and associated renal injury in the porcine model

Dietary hydroxyproline induced calcium oxalate lithiasis and associated renal injury in the porcine model

Dietary Hydroxyproline Induced Calcium Oxalate Lithiasis and Associated Renal Injury in the Porcine Model

We previously reported hyperoxaluria and calcium oxalate calculi in adult pigs (sows) fed hydroxyproline (HP). The purpose of this study was to grossly and histopathologically characterize intrarenal effects in this model. In the swine facility at our campus, we maintained 21 gestating sows, of which 15 received daily treatment (5% HP mixed with dry feed) and 6 received no treatment (controls). Nine were sacrificed at 21 d (three control, six HP). All kidneys were extracted and examined grossly and for radiographic evidence of stones (GE CT scanner, 80kV, 400MA, 1 sec rotation, 0.625 mm slices). Papillary and cortical samples were processed for histologic analysis. Kidneys from treated sows showed significant calculi distributed within the renal papilla on CT, appeared mottled in the renal cortex and papillary areas, and had less distinct corticomedullary borders. Tiny crystals and mucinous debris lined the papillary tips, calices, and pelvis in kidneys from four of six treated sows, and multiple stones were noted at the papillary tips. Hematoxylin and eosin stain revealed crystals in collecting tubules and papillary tips in treated kidneys and none in controls. Yasue staining confirmed crystals in proximal periglomerular tubules of treated but not control animals. Tubular dilation and inflammatory/fibrotic changes were identified in kidneys from treated animals; none of these changes were evident in control kidneys. We report renal damage as a result of dietary-induced hyperoxaluria in adult sows. Specifically, we found crystalluria in proximal periglomerular tubules and collecting ducts, with tubular damage at all segments.

Hippuric acid as a significant regulator of supersaturation in calcium oxalate lithiasis: the physiological evidence.

At present, the clinical significance of existing physicochemical and biological evidence and especially the results we have obtained from our previous in vitro experiments have been analyzed, and we have come to the conclusion that hippuric acid (C6H5CONHCH2COOH) is a very active solvent of Calcium Oxalate (CaOX) in physiological solutions. Two types of experiments have been discussed: clinical laboratory analysis on the urine excretion of hippuric acid (HA) in patients with CaOX lithiasis and detailed measurements of the kinetics of the dissolution of CaOX calculi in artificial urine, containing various concentrations of HA. It turns out that the most probable value of the HA concentration in the control group is approximately ten times higher than the corresponding value in the group of the stone-formers. Our in vitro analytical measurements demonstrate even a possibility to dissolve CaOX stones in human urine, in which increased concentration of HA have been established. A conclusion can be that drowning out HA is a significant regulator of CaOX supersaturation and thus a regulation of CaOX stone formation in human urine. Discussions have arisen to use increased concentration of HA in urine both as a solubilizator of CaOX stones in the urinary tract and on the purpose of a prolonged metaphylactic treatment.

Curative treatment with extracts of Bombax ceiba fruit reduces risk of calcium oxalate urolithiasis in rats

Context: Drawbacks of presently available treatments for urolithiasis necessitate finding the treatment of hyperoxaluria specifically aimed at reduction in oxalate excretion. Interestingly, many Indian tribes use Bombax ceiba L. (Bombacaceae) fruits as a traditional medicine for the treatment of urinary stones.Objective: The present study investigated the efficacy of B. ceiba fruit extracts as curative agents in experimentally induced calcium oxalate urolithiatic rats.Materials and methods: Calcium oxalate lithiasis was induced in rats by oral administration of 0.75% ethylene glycol for 14 consecutive days. Treatments with aqueous and ethanol extract of B. ceiba fruit (400 mg/kg body weight) was performed in the same manner for further 14 consecutive days. Cystone (750 mg/kg body weight) was used as reference antiurolithiatic drug. The urinary excretion and kidney deposition of offending salt components, and serum biochemical parameters were investigated.Results: Oral administration of ethylene glycol resulted in hyperoxaluria and increased renal excretion of calcium and phosphate. However, supplementation with aqueous and ethanol extracts of B. ceiba fruit significantly (p < 0.05) reduced the elevated urinary oxalate, showing a regulatory action on endogenous oxalate synthesis. The increased deposition of stone forming constituents in kidneys of calculogenic rats was also significantly lowered with curative treatment of aqueous and ethanol extract.Discussion and conclusion: The results indicate that the fruit of B. ceiba is endowed with lithontriptic activity warranting further development for curative treatment of urolithiasis.

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.

The initial and subsequent inflammatory events during calcium oxalate lithiasis

Background Crystallization is believed to be the initiation step of urolithiasis, even though it is unknown where inside the nephron the first crystal nucleation occurs. Methods Direct nucleation of calcium oxalate and subsequent events including crystal retention, cellular damage, endocytosis, and hyaluronan (HA) expression, were tested in a two-compartment culture system with intact human proximal tubular HK-2 cell monolayer. Results Calcium oxalate dihydrate (COD) was nucleated and bound onto the apical surface of the HK-2 cells under hypercalciuric and hyperoxaluric conditions. These cells displayed mild cellular damage and internalized some of the adhered crystals within 18 h post-COD-exposure, as revealed by electron microscopy. Prolonged incubation in complete medium caused significant damage to disrupt the monolayer integrity. Furthermore, hyaluronan disaccharides were detected in the harvested media, and were associated with HAS-3 mRNA expression. Conclusion Human proximal cells were able to internalize COD crystals which nucleated directly onto the apical surface, subsequently triggering cellular damage and HAS-3 specific hyaluronan synthesis as an inflammatory response. The proximal tubule cells here demonstrate that it plays an important role in facilitating urolithiasis via endocytosis and creating an inflammatory environment whereby free hyaluronan in tubular fluid can act as crystal-binding molecule at the later segments of distal and collecting tubules.

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.

Dietary Oxalate and Calcium Oxalate Nephrolithiasis

Patients with calcium oxalate kidney stones are advised to decrease the consumption of foods that contain oxalate. We hypothesized that a cutback in dietary oxalate would lead to a decrease in the urinary excretion of oxalate and decreased stone recurrence. We tested the hypothesis in an animal model of calcium oxalate nephrolithiasis. Hydroxy-L-proline (5%), a precursor of oxalate found in collagenous foods, was given with rat chow to male Sprague-Dawley rats. After 42 days rats in group 1 continued on hydroxy-L-proline, while those in group 2 were given chow without added hydroxy-L-proline for the next 21 days. Food and water consumption as well as weight were monitored regularly. Once weekly urine was collected and analyzed for creatinine, calcium, oxalate, lactate dehydrogenase, 8-isoprostane and H(2)O(2). Urinary pH and crystalluria were monitored. Rats were sacrificed at 28, 42 and 63 days, respectively. Renal tissue was examined for crystal deposition by light microscopy. Rats receiving hydroxy-L-proline showed hyperoxaluria, calcium oxalate crystalluria and nephrolithiasis, and by day 42 all contained renal calcium oxalate crystal deposits. Urinary excretion of lactate dehydrogenase, 8-isoprostane and H(2)O(2) increased significantly. After hydroxy-L-proline was discontinued in group 2 there was a significant decrease in urinary oxalate, 8-isoprostane and H(2)O(2). Half of the group 2 rats appeared to be crystal-free. Dietary sources of oxalate can induce hyperoxaluria and crystal deposition in the kidneys with associated degradation in renal biology. Eliminating oxalate from the diet decreases not only urinary oxalate, but also calcium oxalate crystal deposits in the kidneys and improves their function.

Litiasis de oxalato cálcico monohidrato papilar y de cavidad: estudio comparativo de factores etiológicos

The monohydrate calcium oxalate lithiasis (MCO) is divided in two groups depending on the morphologic-crystal structure: papillary (anchorage point on a renal papilla lesion) and cavity (formed in a cavity with low urodynamic capacity). The minimal differences between urinary biochemistry of MCO makers in comparison with healthy population suggests that other factors different than urine biochemistry (professional activity, dietetic habits, systemic diseases) may be related with lithogenesis. The objective of this work is to study such factors, and compare them in both groups of MCO lithiasis (papillary and cavity). We study 40 patients with MCO lithiasis (20 patients papillary and 20 patients cavitary). Medical history was performed (family history of lithiasis; associated diseases such as high blood pressure, diabetes, hyperuricemia, hypercholesterolemia, peptic ulcer disease; dietetic survey to evaluate phytate consumption; professions with high-risk of exposure to toxic agents); 24-hour urine biochemical tests, two-hour urine (pH), and serum biochemical profile were performed. Statistical analysis was performed using student's t test and chi-square. There is a high prevalence of family history of renal lithiasis (45%) without differences between groups. There are not differences in urine or blood biochemical tests. There is a low consumption of phytate-containing foods in both groups, without significant differences. There is a trend to a greater exposure to cytotoxic agents in the papillary group (45%) vs. the cavity group (25%). Hypertension and hyperuricemia are more prevalent in the cavity MCO group (alpha = 0.025 and alpha = 0.010, respectively). Peptic ulcer disease is more prevalent in the papillary MCO group (alpha = 2.025). There are no significant differences in prevalence of hypercholesterolemia or diabetes mellitus between groups. Papillary MCO calculi are associated with a deficit of crystallization inhibitors (phytates), and disorders of the epithelium covering the renal papilla (cytotoxic agents exposure, peptic ulcer disease). Cavity MCO calculi are associated with a deficit of crystallization inhibitors (phytates) and a greater amount of heterogeneous nucleants (organic material induced by diseases such as hypertension, hyperuricemia, hyperglycemia, and hypercholesterolemia).

Role of the organic matter in calcium oxalate lithiasis

Urine contains variable amounts of organic matter derived from cell degradation. The cellular detritus is composed by membranous and cytosolic glycoproteins, etc. The aim of this paper was to study the role of organic matter in calcium oxalate crystal development and to evaluate the action of some crystallization inhibitors on this process. Crystallization studies were carried out on urine in stagnant urine as well as under flow conditions, in presence and absence of cellular debris. Low amounts of cellular debris (when batch conditions were used), exhibited some inhibitory activity on heterogeneous nucleation of calcium oxalate monohydrate crystals, probably due to glycoproteins. Increasing amounts of cellular debris, however, promoted the nucleation of calcium oxalate monohydrate crystals. When cellular debris was retained in a cavity with a urine flow, this organic matter effectively induced the development of primary aggregates of calcium oxalate monohydrate crystals (crystallization range 2.8 mg/h per mg of organic matter). Presence of crystallization inhibitors prevented or minimized crystal development. These findings show that cell debris provides the necessary elements for the development of oxalate crystals and that this process can be effectively inhibited by presence of crystallization inhibitors.

Assessment of Encrustations on Polyurethane Ureteral Stents

To determine the composition and the extent of crystalline (and other) encrustation on ureteral catheters inserted under sterile conditions in stone formers, in comparison with catheters of the same type inserted in nonstone formers for the same time but for different clinical reasons. Forty consecutive self-retained polyurethane pigtail ureteral catheters removed by cystoscopy between November 2000 and February 2002 were studied, 30 from stone formers and 10 from patients without stone histories. The mean dwelling time was 55 days for the stone formers and 79 days for the other patients. The encrustations were collected and analyzed with Fourier-transform infrared spectroscopy, powder X-ray diffraction, or both. The stones from nine of the patients were also subjected to the same spectroscopic analysis. Representative sections of the catheters were investigated by scanning electron microscopy and energy-dispersive X-ray analysis. The most common encrustation in stone formers was calcium oxalate monohydrate. In patients without stones, deposits of organic compounds were found consistently. The mean mass of encrustation of stone formers was larger (71.05 mg) than that of patients without stones (1 mg). Calcium oxalate is the predominant type of encrustation on ureteral catheters in stone formers. Prevention of heavy encrustation should be directed to therapeutic measures concerning calcium oxalate lithiasis and development of new materials by the medical industry that are less prone to encrustation.

Possible causes for the low prevalence of pediatric urolithiasis

Objectives. To determine why the incidence of pediatric urolithiasis is less than that of adult urolithiasis, we investigated the difference in inhibition of calcium oxalate (CaOX) crystallization between pediatric and adult urinary macromolecules (UMMs). Methods. Urinary parameters in relation to urolithiasis, the inhibition of CaOX crystallization of original urine and urine from which UMMs (greater than 3 kDa) had been removed, and the inhibition of CaOX crystal growth and aggregation of UMMs alone were measured. These inhibitory activities were compared between children and adults. Results. In the original urine, the inhibition of CaOX crystallization was significantly stronger for children than for adults, but was the same in urine from which the UMMs had been removed. The inhibition of CaOX crystal growth by UMMs alone showed no significant differences between children and adults; their inhibition of CaOX crystal aggregation was significantly stronger for children than for adults. Much more glycosaminoglycan (GAG) was included in pediatric UMMs than in adult UMMs, although there was no difference in UMM concentration between urine from children and urine from adults. Conclusions. The lower incidence of CaOX lithiasis in children may be attributed, among other factors, to the stronger inhibition of CaOX crystal aggregation by pediatric UMMs, which in turn might be affected by the higher concentration of GAGs in children’s urine.