Calcium Oxalate Crystal Deposition Research Articles

Effect of Costus igneus stem extract on calcium oxalate urolithiasis in albino rats

The effects of aqueous and ethanolic extracts of Costus igneus (stem) and isolated compounds lupeol and stigmasterol on calcium oxalate urolithiasis have been studied in male albino Wistar rats. Ethylene glycol feeding resulted in hyperoxaluria as well as increased renal excretion of calcium and oxalate. The increased deposition of stone-forming constituents in the urine, serum, and kidney homogenate of urolithic rats was significantly (p < 0.05) lowered by treatment using aqueous and ethanolic extracts of C. igneus (stem), and isolated compounds lupeol and stigmasterol. The calcium oxalate crystal deposition in the kidney was significantly greater in ethylene glycol-induced urolithic rats. After administration of aqueous and ethanolic extract of C. igneus, the deposition of calcium and oxalate was significantly lowered. Treatment with lupeol and stigmasterol significantly reduced the deposition of calcium and oxalate in the kidney, and also in the blood serum; the lipid profile serum total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) levels at 50 and 100 mg/kg were significantly (p < 0.05) lowered in urolithiatic rats. From this study, we conclude that both the treatments with aqueous and ethanolic extract of C. igneus (stem) and isolated compounds lupeol and stigmasterol had an inhibitory effect on calcium oxalate urinary stone. Lupeol and stigmasterol were identified from the stem of C. igneus by high-performance thin layer chromatography technique. The isolated compounds were confirmed by Fourier transform infrared (FTIR) and (13)C NMR spectra.

Association of Randall Plaque With Collagen Fibers and Membrane Vesicles

Idiopathic calcium oxalate kidney stones develop by calcium oxalate crystal deposition on Randall plaque. The mechanisms involved in Randall plaque formation are still unclear. We hypothesized that Randall plaque formation is similar to that of vascular calcification, involving components of extracellular matrix, including membrane bound vesicles and collagen fibers. To verify our hypothesis we critically examined renal papillary tissue from patients with stones. We performed 4 mm cold cup biopsy of renal papillae on 15 patients with idiopathic stones undergoing percutaneous nephrolithotomy. Tissue was immediately fixed and processed for analysis by various light and electron microscopic techniques. Spherulitic calcium phosphate crystals, the hallmark of Randall plaque, were seen in all samples examined, including in interstitium and laminated basement membrane of tubular epithelium. Large crystalline deposits were composed of dark elongated strands mixed with spherulites. Strands showed banded patterns similar to collagen. Crystal deposits were surrounded by collagen fibers and membrane bound vesicles. Energy dispersive x-ray microanalysis and electron diffraction identified the crystals as hydroxyapatite. Few kidneys were examined and urinary data were not available on all patients. Results showed that crystals in Randall plaque are associated with collagen and membrane bound vesicles. Collagen fibers appeared calcified and vesicles contained crystals. Crystal deposition in renal papillae may have started with membrane vesicle induced nucleation and grown by the further addition of crystals at the periphery in a collagen framework.

Effect of Lagenaria siceraria fruit powder on sodium oxalate induced urolithiasis in Wistar rats

Background:In spite of advances in the present practice of medicine, the formation and growth of calculi continues to trouble mankind, as there is no satisfactory drug to treat kidney stones. In India, many indigenous drugs are in use for the treatment of urinary calculus disease.Objective:The present study was intended to determine anti-urolithiatic effect of Lagenaria siceraria fruit powder (LSFP) against sodium oxalate (NaOx) induced urolithiasis in rats.Materials and Methods:Animals were grouped as Vehicle Group (received vehicle gum acacia 2% w/v 1 mL/kg/p.o.), NaOx Group(Sodium oxalate 70 mg/kg,i.p.), LSFP Group (500 mg/kg, p.o. LSFP suspended in gum acacia 2% + Sodium oxalate 70 mg/kg), Cystone Group (500 mg/kg, p.o. Cystone suspended in gum acacia 2% + Sodium oxalate 70 mg/kg).Result:The increased severity of microscopic calcium oxalate (CaOx) crystals deposition along with increased concentration in the kidney was seen after 7 days of NaOx (70 mg/kg, i.p.) pre-treatment. LSFP (500 mg/kg, p.o.) and standard marketed formulation Cystone (500 mg/kg, p.o.) caused a significant reversal of NaOx-induced changes in ion excretion and urinary CaOx concentration in 7 days treatment.Conclusion:From the results, it was concluded that LSFP showed beneficial effect against urolithiasis by decreasing CaOx excretion and preventing crystal deposition in the kidney tubules.

Inhibition of calcium oxalate crystal deposition on kidneys of urolithiatic rats by Hibiscus sabdariffa L. extract

The present study aims at systematic evaluation of the calyces of Hibiscus sabdariffa to establish its scientific validity for anti-urolithiatic property using ethylene glycol-induced hyperoxaluria model in male albino rats. Administration of a mixture of 0.75% ethylene glycol and 2% ammonium chloride resulted in hyperoxaluria as well as increased renal excretion of calcium and phosphate. The decrease in the serum calcium concentration indicates an increased calcium oxalate formation. Supplementation of aqueous extract of H. sabdariffa at different doses (250, 500 and 750mg/kg body weight) significantly lowered the deposition of stone-forming constituents in the kidneys and serum of urolithiatic rats. These findings have been confirmed through histological investigations. Results of in vivo genotoxicity testing showed no significant chromosomal aberrations in the bone marrow cells of ethylene glycol-induced rats. The plant extracts at the doses investigated induced neither toxic nor lethal effects and are safe. It can be concluded that the calyces of H. sabdariffa are endowed with anti-urolithiatic activity and do not have genotoxic effects. Thus, it can be introduced in clinical practices and medicine in the form of orally administered syrup after further investigations and clinical trials.

Selective Rac1 inhibition protects renal tubular epithelial cells from oxalate-induced NADPH oxidase-mediated oxidative cell injury

Oxalate-induced oxidative cell injury is one of the major mechanisms implicated in calcium oxalate nucleation, aggregation and growth of kidney stones. We previously demonstrated that oxalate-induced NADPH oxidase-derived free radicals play a significant role in renal injury. Since NADPH oxidase activation requires several regulatory proteins, the primary goal of this study was to characterize the role of Rac GTPase in oxalate-induced NADPH oxidase-mediated oxidative injury in renal epithelial cells. Our results show that oxalate significantly increased membrane translocation of Rac1 and NADPH oxidase activity of renal epithelial cells in a time-dependent manner. We found that NSC23766, a selective inhibitor of Rac1, blocked oxalate-induced membrane translocation of Rac1 and NADPH oxidase activity. In the absence of Rac1 inhibitor, oxalate exposure significantly increased hydrogen peroxide formation and LDH release in renal epithelial cells. In contrast, Rac1 inhibitor pretreatment, significantly decreased oxalate-induced hydrogen peroxide production and LDH release. Furthermore, PKC α and δ inhibitor, oxalate exposure did not increase Rac1 protein translocation, suggesting that PKC resides upstream from Rac1 in the pathway that regulates NADPH oxidase. In conclusion, our data demonstrate for the first time that Rac1-dependent activation of NADPH oxidase might be a crucial mechanism responsible for oxalate-induced oxidative renal cell injury. These findings suggest that Rac1 signaling plays a key role in oxalate-induced renal injury, and may serve as a potential therapeutic target to prevent calcium oxalate crystal deposition in stone formers and reduce recurrence.

A Comparative Study of Experimental Rat Models of Renal Calcium Oxalate Stone Formation

The aim of this study was to design a simple and convenient rat model with significant calcium oxalate crystal deposition in the kidney. Sprague-Dawley rats were divided into seven groups of 30 rats each. One group of rats was untreated to serve as controls. Two of the groups of rats were provided with drinking water supplemented with 1% ethylene glycol (EG), and of these two groups, one group was also administered vitamin D. Two groups of rats received intraperitoneal injections of EG, and of these two groups, one group also received vitamin D. Two groups of rats received intraperitoneal injections of glyoxylate, and of these two groups, one group also received vitamin D. We analyzed 24-hour urine samples for urinary constituents for all experimental groups, including calcium, oxalate, citrate, uric acid, pH, and urine volume. The kidneys were examined for crystal deposition using histologic examination and for osteopontin expression using immunohistochemical staining. Calcium-oxalate crystals were found in all rats injected with glyoxylate after 1 week. The degree of crystal deposition in rats injected with glyoxylate for 1 week was significantly increased compared with rats fed EG for 4 weeks. Intraperitoneal injection of glyoxylate is a faster, more exact, and more reliable method to produce calcium oxalate crystal deposition in the kidney than previous urolithiasis animal models.

Effect of NADPH oxidase inhibition on the expression of kidney injury molecule and calcium oxalate crystal deposition in hydroxy-L-proline-induced hyperoxaluria in the male Sprague-Dawley rats

Renal calcium oxalate (CaOx) crystal deposition is associated with epithelial injury and movement of inflammatory cells into the interstitium. We have proposed that oxalate (Ox)- and CaOx crystal-induced injury is most likely caused by reactive oxygen species (ROS) produced by activation of membrane nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Present study was undertaken to determine the effect of NADPH oxidase inhibitor apocynin on the expression of kidney injury molecule-1 (KIM-1) and renal CaOx crystal deposition in rats with hyperoxaluria. We also investigated the urinary excretion of KIM-1, osteopontin (OPN) and monocyte chemoattractant protein-1 (MCP-1) and renal expression of OPN and ED-1. Male Sprague-Dawley rats were fed a diet containing 5% hydroxyl-L-proline (HLP) and 4 mmol apocynin to drink for 28 days. Urine was collected on Days 7, 14, 21 and 28. After that, rats were sacrificed and their kidneys processed for various microscopic and molecular investigations. HLP consumption produced heavy deposits of CaOx crystals. Renal expression of KIM-1 and OPN and urinary excretion of KIM-1, OPN, H(2)O(2) and MCP-1 was significantly increased. ED-1-positive cells migrated into renal interstitium. Apocynin treatment caused significant reduction of crystal deposits, injured and dilated tubules; renal expression of KIM-1, OPN and ED-1 and urinary excretion of KIM-1, OPN, MCP-1 and H(2)O(2). Apocynin had no effect on the urinary excretion of Ox. This is the first study of urinary excretion and renal expression of KIM-1 in association with renal CaOx crystal deposition, experimental or clinical. The results indicate that NADPH oxidase inhibition leads to reduction in KIM-1 expression and urinary excretion as well as renal CaOx crystal deposition. KIM-1 is an important marker of renal epithelial injury. The results provide further support to our proposal that renal epithelial injury is critical for crystal retention and that injury is in part caused by the production of ROS with the involvement of NADPH oxidase.

Angiotensin Type-1 Receptor Blocker Candesartan Inhibits Calcium Oxalate Crystal Deposition in Ethylene Glycol-Treated Rat Kidneys

To investigate whether an angiotensin type-1 receptor blocker could inhibit calcium oxalate crystal deposition using ethylene glycol-treated rats. The renoprotective effect has been reported to be another role of angiotensin type-1 receptor blockers in addition to their role in lowering blood pressure. Recent research has suggested that inhibiting reactive oxidative species generation and tubulointerstitial inflammation is the major role of angiotensin type-1 receptor blockers. These 2 factors are also important in the mechanism of calcium oxalate stone formation. We divided 28 rats, aged 7 weeks, into 4 groups: group 1, control rats; group 2, candesartan-treated rats; group 3, stone-forming rats; and group 4, candesartan-treated stone-forming rats. The kidney crystal deposits were examined, and the oxidative stress biomarker, nicotinamide adenine dinucleotide phosphate oxidase activity, general and urinary variables, and the transforming growth factor-β level in kidney tissue were compared among the 4 groups. The candesartan-treated rats were healthy and had weight gain similar to that of the control rats, although a significant reduction in blood pressure was observed. The urinary components associated with calcium oxalate stone formation were not influenced by candesartan treatment; however, significantly fewer crystal deposits were observed in group 4. The oxidative biomarker and nicotinamide adenine dinucleotide phosphate oxidase activity decreased, and the level of transforming growth factor-β was suppressed in group 4. Candesartan had substantial effects on crystal formation in the rat kidney by suppressing nicotinamide adenine dinucleotide phosphate oxidase and the transforming growth factor-β levels.

Experimentally induced hyperoxaluria in MCP-1 null mice

Experimental animal model studies suggest that calcium oxalate (CaOx) crystal deposition in the kidneys is associated with the development of oxidative stress, epithelial injury and inflammation. There is increased production of inflammatory molecules including osteopontin (OPN), monocyte chemoattractant protein-1 (MCP-1) and various subunits of inter-alpha-inhibitor such as bikunin. What does the increased production of such molecules suggest? Is it a cause or consequence of crystal deposition? We hypothesized that over-expression and increased production of MCP-1 is a result of the interaction between renal epithelial cells and CaOx crystals after their deposition in the renal tubules. We induced hyperoxaluria in MCP-1 null as well as wild type mice and examined pathological changes in their kidneys and urine. Both wild type and MCP-1 null male mice became hyperoxaluric and demonstrated CaOx crystalluria. Neither of them developed crystal deposits in their kidneys. Both showed some morphological changes in their renal proximal tubules. Significant pathological changes such as cell death and increased urinary excretion of LDH were not seen. Results suggest that at least in mice (1) Increase in oxalate and decrease in citrate excretion can lead to CaOx crystalluria but not CaOx nephrolithiasis; (2) MCP-1 does not play a role in crystal retention within the kidneys; (3) Expression of OPN and MCP-1 is not increased in the kidneys in the absence of crystal deposition; (4) Crystal deposition is necessary for significant pathological changes and movement of monocytes and macrophages into the interstitium.

Antiurolithic effect of berberine is mediated through multiple pathways

Berberine is an isoquinoline alkaloid, occurring in nature as the main constituent of several plants with medicinal use in kidney stone disease. This work was undertaken to evaluate its antiurolithic potential and explore the possible underlying mechanism(s). Berberine was tested in vitro for the antioxidant effect and in vivo for diuretic and antiurolithic effects on an animal model of calcium oxalate urolithiasis. Berberine exhibited concentration-dependent (50–150μg/ml) antioxidant effect against ferrous-ascorbate induced lipid peroxidation in rat kidney homogenate with potency slightly higher than the reference antioxidant, butylated hydroxytoluene. In Wistar rats, berberine (5–20mg/kg) increased urine output accompanied by increased pH and Na+ and K+ excretion and decreased Ca2+ excretion, similar to hydrochlorothiazide. In an animal model of calcium oxalate urolithiasis developed in male Wistar rats by adding 0.75% ethylene glycol in drinking water, berberine (10mg/kg) prevented as well as eliminated calcium oxalate crystal deposition in renal tubules and protected against deleterious effects of lithogenic treatment including weight loss, impaired renal function and oxidative stress, manifested as increased malondialdehyde and protein carbonyl contents, depleted GSH and decreased antioxidant enzyme activities of the kidneys. In naïve rats, berberine (10mg/kg) increased urine volume and pH and decreased Ca2+ excretion. Results of this study suggest the presence of antiurolithic effects in berberine against calcium oxalate stones mediated through a combination of antioxidant, diuretic, urinary alkalinizing and hypocalciuric effects. These data invite future studies on berberine to establish its efficacy for clinical use.

Calcium oxalate crystal deposition in metabolic syndrome model rat kidneys

Although an epidemiological link between the metabolic syndrome and kidney stone formation has been reported, the mechanism by which metabolic syndrome promotes kidney stone formation has yet to be elucidated. We investigated calcium oxalate (CaOx) kidney stone formation in a rat metabolic syndrome model. We induced hyperoxaluria in 8-week-old male Otsuka Long-Evans Tokushima fatty (OLETF) rats, and a control strain, Long-Evans Tokushima Otsuka (LETO) rats, by administering 1.0% ethylene glycol (EG) as their drinking water for 2 weeks. Rats were divided into four groups: LETO-C (control, n = 7); LETO-SF (stone forming, n = 8); OLETF-C (n = 7); and OLETF-SF (n = 8). Urine and blood samples were collected for biochemistry testing, and the kidneys were harvested for estimation of crystal deposition and determinations of the expression of osteopontin (OPN) and monocyte chemoattractant protein-1 (MCP-1). Administration of EG induced hyperoxaluria to the same degree in both strains. The OLETF-SF group showed a higher grade of renal crystal deposition and significantly higher renal calcium content than the LETO-SF group. Although the OLETF-C group excreted significantly higher amounts of uric acid and more acidic urine than the LETO-C group, similar differences were not observed in rats given EG. Significant upregulation of both OPN and MCP-1 was seen in the kidneys of hyperoxaluric rats, with higher levels of expression in the OLETF-SF group than the LETO-SF group. The present results show for the first time that OLETF rats form more renal CaOx crystal deposits compared with control rats under EG-induced hyperoxaluric conditions. The model described here should be useful for investigating the mechanisms by which the metabolic syndrome promotes CaOx kidney stone formation.

Prevention of renal crystal deposition by an extract of Ammi visnaga L. and its constituents khellin and visnagin in hyperoxaluric rats

In Egypt, teas prepared from the fruits of Ammi visnaga L. (syn. "Khella") are traditionally used by patients with urolithiasis. The aim of this study was to evaluate whether oral administration of an aqueous extract prepared from the fruits of A. visnaga as well as two major constituents khellin and visnagin could prevent crystal deposition in stone-forming rats. Hyperoxaluria was induced in male Sprague-Dawley rats by giving 0.75% ethylene glycol and 1% ammonium chloride via the drinking water. The Khella extract (KE; 125, 250 or 500mg/kg) was orally administered for 14days. The histopathological examination of the kidneys revealed that KE significantly reduced the incidence of calcium oxalate (CaOx) crystal deposition. In addition, KE significantly increased urinary excretion of citrate along with a decrease of oxalate excretion. Comparable to the extract, khellin and visnagin significantly reduced the incidence of CaOx deposition in the kidneys. However, both compounds did not affect urinary citrate or oxalate excretion indicating a mechanism of action that differs from that of the extract. For KE, a reasonably good correlation was observed between the incidence of crystal deposition, the increase in citrate excretion and urine pH suggesting a mechanisms that may interfere with citrate reabsorption. In conclusion, our data suggest that KE and its compounds, khellin and visnagin, may be beneficial in the management of kidney stone disease caused by hyperoxaluria but that it is likely that different mechanism of action are involved in mediating these effects.

Severe Periodontitis in a Patient With Hyperoxaluria and Oxalosis: A Case Report and Review of the Literature

Hyperoxaluria is a metabolic disease with excessive urinary oxalate excretion that can be primary or secondary. Hyperoxaluria can result in chronic renal disease and renal failure. Calcium oxalate crystals can be deposited in oral tissues, and the disease can be associated with severe periodontitis and tooth loss. The periodontal condition of a 38-year-old patient with a diagnosis of hyperoxaluria and end-stage renal disease is presented. The patient's periodontal status was monitored over a period of several weeks, and extracted teeth were submitted for histopathologic evaluation. The patient was diagnosed with generalized severe periodontitis and external root resorption. Initial periodontal treatment consisting of oral-hygiene instructions and scaling and root planing was performed. However, despite an initial decrease of soft tissue inflammation, the patient's periodontal condition deteriorated, and eventually, all teeth had to be extracted. The deposition of calcium oxalate crystals in the periodontal tissues was confirmed histologically. Long-standing hyperoxaluria can be associated with severe periodontitis and external root resorption resulting in tooth loss. The pathogenetic mechanisms of hard tissue destruction are still unclear.

Experimental Induction of Calcium Oxalate Nephrolithiasis in Mice

The availability of various transgenic and knockout mice provides an excellent opportunity to better understand the pathophysiology of calcium oxalate stone disease. However, attempts to produce calcium oxalate nephrolithiasis in mice have not been successful. We hypothesized that calcium oxalate nephrolithiasis in mice requires increasing urine calcium and oxalate excretion, and experimentally induced hyperoxaluria alone is not sufficient. To provide evidence we induced hyperoxaluria by administering hyperoxaluria inducing agents in normocalciuric and hypercalciuric mice, and investigating various aspects of nephrolithiasis. We administered ethylene glycol, glyoxylate or hydroxyl proline via diet in male and female normocalciuric B6 mice, and in hypercalciuric sodium phosphate co-transporter type 2 a -/- mice for 4 weeks. We collected 24-hour urine samples on days 0, 3, 7, 14, 21 and 28, and analyzed them for pH, creatinine, lactate dehydrogenase calcium and oxalate. Kidneys were examined using light microscopy. Urine was examined for crystals using light and scanning electron microscopy. Hypercalciuric mice on hydroxyl proline did not tolerate treatment and were sacrificed before 28 days. All mice on ethylene glycol, glyoxylate or hydroxyl proline became hyperoxaluric and showed calcium oxalate crystalluria. No female, normocalciuric or hypercalciuric mice showed renal calcium oxalate crystal deposits. Calcium oxalate nephrolithiasis developed in all mice on glyoxylate and in some on ethylene glycol. In all mice the kidneys showed epithelial injury. Male mice particularly on glyoxylate had more renal injury and inflammatory cell migration into the interstitium around the crystal deposits. Results confirm that hyperoxaluria induction alone is not sufficient to create calcium oxalate nephrolithiasis in mice. Hypercalciuria is also required. Kidneys in male mice are more prone to injury than those in female mice and are susceptible to calcium oxalate crystal deposition. Perhaps epithelial injury promotes crystal retention. Thus, calcium oxalate nephrolithiasis in mice is gender dependent, and requires hypercalciuria and hyperoxaluria.

Proteome Changes in Human Monocytes upon Interaction with Calcium Oxalate Monohydrate Crystals

Monocytic infiltration in renal interstitium is commonly found surrounding the site of calcium oxalate (CaOx) crystal deposition in the kidney. Monocytes are supposed to eliminate the deposited crystals. However, effects of CaOx crystals on the infiltrating monocytes remain unknown. Therefore, this study investigated the altered cellular proteome of human monocytes in response to interaction with CaOx monohydrate (COM) crystals. After 24-h culture with or without 100 microg/mL COM crystals, U937 cells were harvested and subjected to 2-DE analysis with Deep Purple fluorescence staining (n = 5 gels/group; each was derived from independent culture). Spot matching, quantitative intensity analysis, and statistics revealed 22 differentially expressed proteins (9 up-regulated and 13 down-regulated proteins), which were successfully identified by Q-TOF MS and MS/MS analyses, including those involved in cell cycle, cellular structure, carbohydrate metabolism, lipid metabolism, mRNA processing, and protein synthesis, stabilization, and degradation. Randomly selected changes [up-regulated ALG-2 interacting protein 1 (Alix), elongation factor-2 (EF-2), and down-regulated beta-actin] were confirmed by Western blot analysis. Our data may help to understand how monocytes interact with COM crystals. These processes are proposed to cause subsequent inflammatory response in kidney stone disease through oxidative stress pathway(s).

Orthosiphon grandiflorum has a protective effect in a calcium oxalate stone forming rat model

This study amied to investigate the effects of Orthosiphon grandiflorum on the renal tubular cell injury induced by oxalate and the inhibitory effects of O. grandiflorum on urinary deposit formation in an animal model and compared the results with those from a potassium citrate treatment. Rats were divided into three groups: an untreated stone-forming group, an O. grandiflorum-treated stone-forming group and a potassium citrate-treated stone forming group. Ethylene glycol (0.5%) was administered to the rats during the last week, and vitamin D3 (0.5 mum) was force fed to induce hyperoxaluria and kidney calcium oxalate crystal deposition. Twenty-four hour urine samples were collected before and after inducing crystal deposits. Rats were killed and both kidneys were harvested after 3 weeks. Bisected kidneys were examined under a polarized light microscope to determine the number of crystals. The renal tissue superoxide dismutase and catalase levels were measured by Western blot. Oxidative stress was examined by 8-OHdG immunohistofluorescence. O. grandiflorum and potassium citrate have the ability to alkalinize urine. Among all groups, the number of crystal deposits and the level of 8-OHdG staining decreased significantly in the O. grandiflorum-treated stone forming group, as compared to the other groups. Superoxide dismutase and catalase levels also increased significantly in the O. grandiflorum-treated stone-forming group, as compared with the untreated stone-forming group. The results indicate that O. grandiflorum has a significant inhibitory effect on crystal deposition in the calcium oxalate-stone-forming rat model.

Bone metabolism in oxalosis: a single-center study using new imaging techniques and biomarkers

The deposition of calcium oxalate crystals in the kidney and bone is a hallmark of primary hyperoxaluria type 1 (PH1). We report here an evaluation of the bone status of 12 PH1 children based on bone biomarkers [parathyroid hormone, vitamin D, fibroblast growth factor 23 (FGF23)] and radiological assessments (skeletal age, three-dimensional high-resolution peripheral quantitative computed tomography, HR-pQCT) carried out within the framework of a cross-sectional single-center study. The controls consisted of healthy and children with chronic kidney disease already enrolled in local bone and mineral metabolism studies. The mean age (+ or - standard deviation) age of the patients was 99 (+ or - 63) months. Six children suffered from fracture. Bone maturation was accelerated in five patients, four of whom were <5 years. The combination of new imaging techniques and biomarkers highlighted new and unexplained features of PH1: advanced skeletal age in young PH1 patients, increased FGF23 levels and decreased total volumetric bone mineral density with bone microarchitecture alteration.

Renal Cell Carcinoma With Calcium Oxalate Deposition

Abstract: Cystic changes may develop in kidneys of patients with end-stage renal disease treated with long-term dialysis, a condition termed acquired cystic kidney disease. Renal neoplasms frequently develop in this process and they display a wide morphologic spectrum encompassing all of the usual renal tumors. However, one histologic type among them, characterized by tumoral deposition of calcium oxalate crystals, is seen only in the context of acquired cystic kidney disease. This communication reports one such tumor and reviews the clinicopathologic features of acquired cystic kidney disease and the renal neoplasms associated with this condition, with special emphasis on the particular renal cell carcinoma associated with tumoral calcium oxalate deposition.

Encapsulating Peritoneal Sclerosis in a Patient with Primary Hyperoxaluria Type 1: A Case Report

Primary hyperoxaluria type 1 (PH1) is a rare metabolic disorder caused by a defect in glyoxylate metabolism attributable to low or absent activity of the liver-specific peroxisomal enzyme alanine/glyoxylate aminotransferase. This defect leads to enhanced conversion of glyoxylate to poorly soluble oxalate, which is then excreted into the urine. This process may lead to deposition of calcium oxalate crystals in many tissues as well as in the kidneys, resulting in nephrolithiasis, nephrocalcinosis, and/or renal failure. We present a 39-year-old patient with end-stage renal failure due to PH1, who was admitted with symptoms of feeling bloated, vomiting, diarrhea, and abdominal pain related to encapsulating peritoneal sclerosis (EPS). He had been treated with peritoneal dialysis for a total period of 5 years. EPS is a rare condition characterized by fibrosis and adhesions of the peritoneum to loops of the small intestine and has been described secondary to treatment with peritoneal dialysis. It also occurs in a variety of other clinical conditions such as autoimmune diseases and peritoneal and intra-abdominal malignancies. The calcium oxalate crystals found in the peritoneal fascia of this particular patient may suggest a causative relationship between crystal deposits and evolution to fibrosis and sclerosis of the peritoneum. The degree of impact of the peritoneal dialysis treatment itself on the development of EPS, however, is uncertain.

Late diagnosis of primary hyperoxaluria after failed kidney transplantation

Primary hyperoxaluria type 1 (PH1) is a rare autosomal recessive inborn error of the glyoxylate metabolism that is based on absence, deficiency or mislocalization of the liver-specific peroxisomal enzyme alanine:glyoxylate aminotransferase. Hyperoxaluria leads to recurrent formation of calculi and/or nephrocalcinosis and often early end-stage renal disease (ESRD) accompanied by systemic calcium oxalate crystal deposition. In this report, we describe an adult female patient with only one stone passage before development of ESRD. With unknown diagnosis of PH, the patient received an isolated kidney graft and developed an early onset of graft failure. Although initially presumed as an acute rejection, the biopsy revealed calcium oxalate crystals, which then raised a suspicion of primary hyperoxaluria. The diagnosis was later confirmed by hyperoxaluria, elevated plasma oxalate levels and mutation of the AGXT gene, showing the patient to be compound heterozygous for the c.33_34InsC and c.508G > A mutations. Plasma oxalate levels did not decrease after high-dose pyridoxine treatment. Based on this case report, we would recommend in all patients even with a minor history of nephrolithiasis but progression to chronic renal failure to exclude primary hyperoxaluria before isolated kidney transplantation is considered.