oxalates and Disease-Models--Animal

Oxalate is both a plant-derived molecule and a terminal toxic metabolite with no known physiological function in humans. It is predominantly eliminated by the kidneys through glomerular filtration and tubular secretion. Regardless of the cause, the increased load of dietary oxalate presented to the kidneys has been linked to different kidney-related conditions and injuries, including calcium oxalate nephrolithiasis, acute and chronic kidney disease. In this paper, we review the current literature on the association between dietary oxalate intake and kidney outcomes.

Topics: Animals; Diet; Disease Models, Animal; Glomerular Filtration Rate; Humans; Kidney; Nephrolithiasis; Oxalates; Randomized Controlled Trials as Topic

The primary hyperoxalurias (PHs) are inborn errors of glyoxylate metabolism characterized by endogenous oxalate overproduction in the liver, and thus elevated urinary oxalate excretion. The urinary calcium-oxalate (CaOx) supersaturation and the continuous renal accumulation of insoluble CaOx crystals yield a progressive decline in renal function that often ends with renal failure. In PH Type 1 (AGXT mutated), the most frequent and severe condition, patients typically progress to end-stage renal disease (ESRD); in PH Type 2 (GRHPR mutated), 20% of patients develop ESRD, while only one patient with PH Type 3 (HOGA1 mutated) has been reported with ESRD so far. Patients with ESRD undergo frequent maintenance (haemo)dialysis treatment, and finally must receive a combined liver-kidney transplantation as the only curative treatment option available in PH Type 1. In experimental models using oxalate-enriched chow, CaOx crystals were bound to renal tubular cells, promoting a pro-inflammatory environment that led to fibrogenesis in the renal parenchyma by activation of a NACHT, LRR and PYD domains-containing protein 3 (NALP3)-dependent inflammasome in renal dendritic cells and macrophages. Chronic fibrogenesis progressively impaired renal function. Targeting the inflammatory response has recently been suggested as a therapeutic strategy to treat not only oxalate-induced crystalline nephropathies, but also those characterized by accumulation of cystine and urate in other organs. Herein, we summarize the pathogenesis of PH, revising the current knowledge of the CaOx-mediated inflammatory response in animal models of endogenous oxalate overproduction. Furthermore, we highlight the possibility of modifying the NLRP3-dependent inflammasome as a new and complementary therapeutic strategy to treat this severe and devastating kidney disease.

Topics: Adolescent; Adult; Animals; Calcium Oxalate; Child; Child, Preschool; Disease Models, Animal; Humans; Hyperoxaluria, Primary; Infant; Inflammasomes; Kidney; Kidney Failure, Chronic; Kidney Transplantation; Macrophages; Mice; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Renal Dialysis; Renal Insufficiency; RNA Interference; Uric Acid; Young Adult

Solute-linked carrier 26 (SLC26) isoforms constitute a conserved family of anion transporters with 10 distinct members. Except for SLC26A5 (prestin), all can operate as multifunctional anion exchangers, with three members (SLC26A7, SLC26A9, and SLC26A11) also capable of functioning as chloride channels. Several SLC26 isoforms can specifically mediate Cl(-)/HCO(3)(-) exchange. These include SLC26A3, A4, A6, A7, A9, and A11, which are expressed in the kidney except for SLC26A3 (DRA), which is predominantly expressed in the intestine. SLC26 Cl(-)/HCO(3)(-) exchanger isoforms display unique nephron segment distribution patterns with distinct subcellular localization in the kidney tubules. Together with studies in pathophysiologic states and the examination of genetically engineered mouse models, the evolving picture points to important roles for the SLC26 family in health and disease states. This review summarizes recent advances in the characterization of the SLC26 Cl(-)/HCO(3)(-) exchangers in the kidney with emphasis on their essential role in diverse physiological processes, including chloride homeostasis, oxalate excretion and kidney stone formation, vascular volume and blood pressure regulation, and acid-base balance.

Topics: Acid-Base Equilibrium; Animals; Antiporters; Chloride-Bicarbonate Antiporters; Chlorides; Disease Models, Animal; Homeostasis; Humans; Kidney; Kidney Diseases; Membrane Transport Proteins; Mice; Oxalates; Sulfate Transporters

The majority of the Na(+) and Cl(-) filtered by the kidney is reabsorbed in the proximal tubule. In this nephron segment, a significant fraction of Cl(-) is transported via apical membrane Cl(-)-base exchange: Cl(-)-formate exchange, Cl(-)-oxalate exchange, Cl(-)-OH(-) exchange, and Cl(-)-HCO(3)(-) exchange. A search for the transporter responsible for apical membrane Cl(-)-formate exchange in the proximal tubule led to the identification of CFEX (SLC26A6). Functional expression studies in Xenopus oocytes demonstrated that CFEX is capable of mediating not only Cl(-)-formate exchange but also Cl(-)-oxalate exchange, Cl(-)-OH(-) exchange, and Cl(-)-HCO(3)(-) exchange. Studies in CFEX-null mice have begun to elucidate which of the anion exchange activities mediated by CFEX is important for renal physiology and pathophysiology in vivo. Measurements of transport in renal brush border vesicles isolated from CFEX-null mice demonstrated that CFEX primarily mediates Cl(-)-oxalate exchange rather than Cl(-)-formate exchange. Microperfusion studies in CFEX-null mice revealed that CFEX plays an essential role in mediating oxalate-dependent NaCl absorption in the proximal tubule. CFEX-null mice were found to have hyperoxaluria and a high incidence of calcium oxalate urolithiasis. The etiology of hyperoxaluria in CFEX-null mice was observed to be a defect in oxalate secretion in the intestine, leading to enhanced net absorption of ingested oxalate and elevation of plasma oxalate. Thus, by virtue of its function as a Cl(-)-oxalate exchanger, CFEX plays essential roles both in proximal tubule NaCl transport and in the prevention of hyperoxaluria and calcium oxalate nephrolithiasis.

Topics: Animals; Antiporters; Calcium Oxalate; Chloride-Bicarbonate Antiporters; Chlorides; Disease Models, Animal; Formates; Homeostasis; Humans; Hyperoxaluria; Immunohistochemistry; Intestinal Absorption; Ion Exchange; Kidney Tubules, Proximal; Mice; Mice, Knockout; Models, Biological; Nephrolithiasis; Oocytes; Oxalates; Sodium Chloride; Sulfate Transporters; Xenopus

In this review, we focus on the role of gastrointestinal transport of oxalate primarily from a contemporary physiological standpoint with an emphasis on those aspects that we believe may be most important in efforts to mitigate the untoward effects of oxalate. Included in this review is a general discussion of intestinal solute transport as it relates to oxalate, considering cellular and paracellular avenues, the transport mechanisms, and the molecular identities of oxalate transporters. In addition, we review the role of the intestine in oxalate disease states and various factors affecting oxalate absorption.

Topics: Animals; Anions; Biological Transport; Disease Models, Animal; Gastrointestinal Tract; Humans; Intestinal Absorption; Intestinal Mucosa; Intestines; Oxalates; Oxalobacter formigenes

Krüppel-like factor 2 (KLF2) and NLR family pyrin domain containing 3 (NALP3) are important regulators of macrophage activation in the context of various pathological conditions. NALP3 also plays an important role in the maturation of IL-1 β which is central to the pathogenesis of acute oxalate nephropathy. The functional role of KLF2 and regulation of both KLF2 and NALP3 in the pathogenesis of acute oxalate nephropathy is comparably less studied. Here, we explored the regulation of KLF2 and NALP3 by Histone deacetylase 5 (HDAC5) in oxalate crystals stimulated macrophages, and in the pathogenesis of acute oxalate nephropathy in mice. We observed upregulated expression of HDAC5 along with IL-1β, Caspase1, and NALP3, while the expression of KLF2 was downregulated in stimulated macrophages and in the renal tissue of mice with acute oxalate nephropathy. We formulated chitosan HDAC5 siRNA nanoparticles to deliver the siRNA in in-vitro and in-vivo settings. siHDAC5 treated cells exhibited decreased expression of IL-1β, and TNF-α in the supernatant, and reduced expression of NALP3, Pro-caspase1, active caspase1, Pro-IL-1β, and IL-1β in cell lysate. Concurrently, the expression of KLF2 was upregulated in HDAC5 depleted cells upon stimulation with crystals. Mice treated with siHDAC5 nanoparticles showed protection against renal impairment with improved renal function (plasma BUN and creatinine levels), reduced inflammation (IL-1β expression), reduced accumulation of neutrophils, reduced tubular injury, reduced acute renal injury markers (KIM-1, NGAL-1), reduced expression of NALP3, Pro-caspase1, active caspase1, Pro-IL-1β, and IL-1β. Whereas, the expression of KLF2 was significantly upregulated by depletion of HDAC5 in mice.

Topics: Acute Kidney Injury; Animals; Chitosan; Creatinine; Disease Models, Animal; Histone Deacetylases; Inflammasomes; Interleukin-1beta; Kruppel-Like Transcription Factors; Lipocalin-2; Mice; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; RNA Interference; RNA, Small Interfering; Transcription Factors; Tumor Necrosis Factor-alpha

Accumulated clinical and biomedical evidence indicates that the gut microbiota and their metabolites affect brain function and behavior in various central nervous system disorders. This study was performed to investigate the changes in brain metabolites and composition of the fecal microbial community following injection of amyloid β (Aβ) and donepezil treatment of Aβ-injected mice using metataxonomics and metabolomics. Aβ treatment caused cognitive dysfunction, while donepezil resulted in the successful recovery of memory impairment. The Aβ + donepezil group showed a significantly higher relative abundance of Verrucomicrobia than the Aβ group. The relative abundance of 12 taxa, including

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Cognitive Dysfunction; Disease Models, Animal; Donepezil; Gastrointestinal Microbiome; Glutamic Acid; Glycerol; Hypoxanthines; Inosine; Mice; Oxalates; Phenylalanine; Pyrrolidonecarboxylic Acid; Xylose

Steroid sapogenin diosgenin is of significant interest due to its biological activity and synthetic application. A consecutive one-pot reaction of diosgenin, oxalyl chloride, arylacetylenes, and phenylhydrazine give rise to steroidal 1,3,5-trisubstituted pyrazoles (isolated yield 46-60%) when the Stephens-Castro reaction and heterocyclization steps were carried out by heating in benzene. When the cyclization step of alkyndione with phenylhydrazine was performed in 2-methoxyethanol at room temperature, steroidal α,β-alkynyl (

Topics: Animals; Anti-Inflammatory Agents; Chemistry Techniques, Synthetic; Chlorides; Combinatorial Chemistry Techniques; Diosgenin; Disease Models, Animal; Edema; Hydrazines; Hydrazones; Mice; Models, Molecular; Molecular Conformation; Molecular Docking Simulation; Molecular Dynamics Simulation; Molecular Structure; Oxalates; Pyrazoles

Cardiovascular disease is the most common cause of morbidity and mortality in patients with ESRD. In addition to phosphate overload, oxalate, a common uremic toxin, is also involved in vascular calcification in patients with ESRD. The present study investigated the role and mechanism of hyperoxalemia in vascular calcification in mice with uremia.. A uremic atherosclerosis (UA) model was established by left renal excision and right renal electrocoagulation in apoE-/- mice to investigate the relationship between oxalate loading and vascular calcification. After 12 weeks, serum and vascular levels of oxalate, vascular calcification, inflammatory factors (TNF-α and IL-6), oxidative stress markers (malondialdehyde [MDA], and advanced oxidation protein products [AOPP]) were assessed in UA mice. The oral oxalate-degrading microbe Oxalobacter formigenes (O. formigenes) was used to evaluate the effect of a reduction in oxalate levels on vascular calcification. The mechanism underlying the effect of oxalate loading on vascular calcification was assessed in cultured human aortic endothelial cells (HAECs) and human aortic smooth muscle cells (HASMCs).. Serum oxalate levels were significantly increased in UA mice. Compared to the control mice, UA mice developed more areas of aortic calcification and showed significant increases in aortic oxalate levels and serum levels of oxidative stress markers and inflammatory factors. The correlation analysis showed that serum oxalate levels were positively correlated with the vascular oxalate levels and serum MDA, AOPP, and TNF-α levels, and negatively correlated with superoxide dismutase activity. The O. formigenes intervention decreased serum and vascular oxalate levels, while did not improve vascular calcification significantly. In addition, systemic inflammation and oxidative stress were also improved in the O. formigenes group. In vitro, high concentrations of oxalate dose-dependently increased oxidative stress and inflammatory factor expression in HAECs, but not in HASMCs.. Our results indicated that hyperoxalemia led to the systemic inflammation and the activation of oxidative stress. The reduction in oxalate levels by O. formigenes might be a promising treatment for the prevention of oxalate deposition in calcified areas of patients with ESRD.

Topics: Animals; Atherosclerosis; Cell Line; Disease Models, Animal; Endothelial Cells; Humans; Male; Mice; Oxalates; Oxidative Stress; Renal Insufficiency, Chronic; Uremia; Vascular Calcification

Polysialic acid (PSA) is crucial for the induction and maintenance of nervous system plasticity and repair after injury. In order to exploit the immense therapeutic potential of PSA, previous studies have focused on the identification and development of peptide-based or synthetic PSA mimetics. 5-Nonyloxytryptamine (5-NOT) has been previously reported as a PSA-mimicking compound for promoting functional recovery after spinal cord injury in mice. In order to explore the neuroregeneration potential of 5-NOT, the current study was based on a biomaterial approach using collagen-laminin (C/L) scaffolds. In in vitro studies, 5-NOT was observed to promote neurite outgrowth, migration, and fasciculation in cerebellar neuronal cells, whereas in 3D cell cultures it showed more ramification and complex Sholl profiles. 5-NOT promoted the survival and neurite length of cortical neurons when cocultured with glutamate-challenged astrocytes. In in vivo studies, spinal cord compression injury mice were used with immediate application of C/L hydrogels impregnated with 5-NOT. C/L + 5-NOT-treated mice demonstrated ∼75% of motor recovery 14 days after injury. Furthermore, this effect was shown to be dependent on the ERK-MAPK pathway and augmentation of cell survival. Thus, based on a biomaterial approach, our current study provides new insight for 5-NOT-containing hydrogels as a promising candidate to speed up recovery after central nervous system injuries.

Topics: Animals; Cell Survival; Collagen; Disease Models, Animal; Humans; Laminin; Mice; Nerve Regeneration; Neurons; Oxalates; Oximes; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Tissue Scaffolds

The major clinical manifestation of the Primary Hyperoxalurias (PH) is increased production of oxalate, as a consequence of genetic mutations that lead to aberrant glyoxylate and hydroxyproline metabolism. Hyperoxaluria can lead to the formation of calcium-oxalate kidney stones, nephrocalcinosis and renal failure. Current therapeutic approaches rely on organ transplants and more recently modifying the pathway of oxalate synthesis using siRNA therapy. We have recently reported that the metabolism of trans-4-hydroxy-L-proline (Hyp), an amino acid derived predominantly from collagen metabolism, is a significant source of oxalate production in individuals with PH2 and PH3. Thus, the first enzyme in the Hyp degradation pathway, hydroxyproline dehydrogenase (HYPDH), represents a promising therapeutic target for reducing endogenous oxalate production in these individuals. This is supported by the observation that individuals with inherited mutations in HYPDH (PRODH2 gene) have no pathological consequences. The creation of mouse models that do not express HYPDH will facilitate research evaluating HYPDH as a target. We describe the phenotype of the Prodh2 knock out mouse model and show that the lack of HYPDH in PH mouse models results in lower levels of urinary oxalate excretion, consistent with our previous metabolic tracer and siRNA-based knockdown studies. The double knockout mouse, Grhpr KO (PH2 model) and Prodh2 KO, prevented calcium-oxalate crystal deposition in the kidney, when placed on a 1% Hyp diet. These observations support the use of the Grhpr KO mice to screen HYPDH inhibitors in vivo. Altogether these data support HYPDH as an attractive therapeutic target for PH2 and PH3 patients.

Topics: Amino Acid Sequence; Animals; Base Sequence; Calcium; Disease Models, Animal; Female; Glycolates; Humans; Hydroxyproline; Hyperoxaluria, Primary; Kidney; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxalates; Oxidoreductases; Proline Oxidase

Chemiluminescence (CL) sensing without external excitation by light and autofluorescence interference has been applied to high-contrast in vitro immunoassays and in vivo inflammation and tumor microenvironment detection. However, conventional CL sensing usually operates in the range of 400-850 nm, which limits the performance of in vivo imaging due to serious light scattering effects and signal attenuation in tissue. To address this challenge, a new type of CL sensor is presented that functions in the second near-infrared window (NIR-II CLS) with a deep penetration depth (≈8 mm). Successive CL resonance energy transfer (CRET) and Förster resonance energy transfer (FRET) from the activated CL substrate to two rationally designed donor-acceptor-donor fluorophores BTD540 and BBTD700 occurs. NIR-II CLS can be selectively activated by hydrogen peroxide over other reactive oxygen species (ROSs). Moreover, NIR-II CLS is capable of detecting local inflammation in mice with a 4.5-fold higher signal-to-noise ratio (SNR) than that under the NIR-II fluorescence modality.

Topics: Animals; Disease Models, Animal; Fluorescence Resonance Energy Transfer; Fluorescent Dyes; Hydrogen Peroxide; Inflammation; Infrared Rays; Luminescent Measurements; Lymph Nodes; Mice; Optical Imaging; Oxalates; Oxidation-Reduction; Signal-To-Noise Ratio

A state of oxalate homeostasis is maintained in patients with healthy kidney function. However, as GFR declines, plasma oxalate (P. Feeding a diet high in soluble oxalate or weekly injections of aristolochic acid induced CKD in age- and sex-matched wild-type and. Fecal oxalate excretion was enhanced in wild-type mice with CKD. This increase was abrogated in. Slc26a6-mediated enteric oxalate secretion is critical in decreasing the body burden of oxalate in murine CKD models. Future studies are needed to address whether similar mechanisms contribute to intestinal oxalate elimination in humans to enhance extrarenal oxalate clearance.

Topics: Animals; Antiporters; Disease Models, Animal; Intestinal Mucosa; Male; Mice; Mice, Inbred C57BL; Oxalates; Renal Insufficiency, Chronic; Sulfate Transporters

Topics: Animals; Bacterial Adhesion; Cecum; Diet; Disease Models, Animal; Feces; Gastrointestinal Microbiome; HT29 Cells; Humans; Hyperoxaluria; Kidney; Lactobacillus acidophilus; Male; Mice; Mice, Inbred C57BL; Oxalates; Phyllanthus; Phytotherapy; Plant Extracts; Probiotics

In rats, we recently showed how a chronic metabolic acidosis simultaneously reduced urinary oxalate excretion and promoted oxalate secretion by the distal colon leading to the proposition that acid-base disturbances may trigger changes to renal and intestinal oxalate handling. The present study sought to reproduce and extend these observations using the mouse model, where the availability of targeted gene knockouts (KOs) would offer future opportunities to reveal some of the underlying transporters and mechanisms involved. Mice were provided with a sustained load of acid (NH

Topics: Acetazolamide; Acidosis; Ammonium Chloride; Animals; Carbonic Anhydrase Inhibitors; Carbonic Anhydrases; Disease Models, Animal; Female; Homeostasis; Humans; Intestinal Mucosa; Kidney; Kidney Calculi; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxalates; Rats; Renal Elimination; Species Specificity

To test the effect of calcium and vitamin B6 therapies on urinary oxalate excretion in a rodent model of enteric hyperoxaluria after Roux-en Y gastric bypass (RYGB) surgery.. Obese male Sprague-Dawley rats underwent sham (n = 7) or RYGB (n = 10). Animals were maintained on low oxalate (1.5%) and fat (10%; LOF), normal calcium (0.6 %) diet for 8 weeks and then completed a 2-phase crossover metabolic study. In the first 2-week phase, animals were fed a Low oxalate and fat (LOF), high calcium (2.4%; HC) diet. After a 2-week washout, rats were fed a LOF/normal calcium diet highly enriched with vitamin B6. Urine was collected before and after each intervention. Plasma pyridoxal 5'-phosphate (PLP) and metabolites were measured baseline and 11 weeks after sham or RYGB.. Compared to baseline, sham animals on LOF/HC diet doubled their urinary calcium excretion but not oxalate. RYGB animals on LOF/HC diet decreased urinary oxalate excretion 28% (P = .001) without a significant rise in urinary calcium. Vitamin B6 supplementation decreased RYGB urinary oxalate by approximately 15% (P = .06), and serum PLP explained 63% of urinary oxalate variability.. Based on the findings in this model, calcium supplementation appears to be a reasonable therapy to decrease urinary oxalate in RYGB patients who maintain a low fat and oxalate diet. Serum PLP had a fair correlation to urinary oxalate excretion and may be a useful screening tool in hyperoxaluric RYGB patients. Further experimental human studies after RYGB are necessary to determine whether these commonly employed supplements truly provide a benefit in enteric hyperoxaluria.

Topics: Animals; Calcium; Dietary Supplements; Disease Models, Animal; Gastric Bypass; Hyperoxaluria; Male; Oxalates; Postoperative Complications; Rats; Rats, Sprague-Dawley; Vitamin B 6; Vitamin B Complex

Primary Hyperoxaluria Type 1 (PH1) is an autosomal recessive disorder of glyoxylate metabolism. Loss of alanine glyoxylate aminotransferase (AGT) function to convert intermediate metabolite glyoxylate to glycine causes the accumulation and reduction of glyoxylate to glycolate, which eventually is oxidized to oxalate. Excess oxalate in PH1 patients leads to the formation and deposition of calcium oxalate crystals in the kidney and urinary tract. Oxalate crystal deposition causes a decline in renal function, systemic oxalosis, and eventually end-stage renal disease and premature death. mRNA-based therapies are a new class of drugs that work by replacing the missing enzyme. mRNA encoding AGT has the potential to restore normal glyoxylate to glycine metabolism, thus preventing the buildup of calcium oxalate in various organs. Panels of codon-optimized AGT mRNA constructs were screened in vitro and in wild-type mice for the production of a functional AGT enzyme. Two human constructs, wild-type and engineered AGT (RHEAM), were tested in Agxt

Topics: Animals; Disease Models, Animal; Genetic Vectors; Glyoxylates; Humans; Hyperoxaluria, Primary; Liver; Mice; Mice, Knockout; Oxalates; RNA, Messenger; Transaminases

Treatment targeting osteopontin (OPN) and monocyte chemoattractant protein 1 (MCP‑1) has been recognized as a novel approach in renal crystal formation. The present study was designed to investigate the suppressive effects of metformin on nephrolithiasis formation and its potential mechanism. The cytotoxicity of metformin on MDCK and HK‑2 cells was determined using a Cell Counting Kit‑8 assay in vitro. Subsequently, the mRNA transcription and protein expression levels of MCP‑1 and OPN were detected by reverse transcription‑quantitative‑polymerase chain reaction analysis, western blot analysis and ELISA. Male Sprague‑Dawley rats were divided into a control group, ethylene glycol (EG) group and EG + metformin group. The expression levels of MCP‑1 and OPN and crystal formations were evaluated in renal tissues following an 8‑week treatment period. In vitro, metformin significantly inhibited the production of MCP‑1 and OPN induced by oxalate at the mRNA and protein expression levels. In vivo, increased expression levels of MCP‑1 and OPN were detected in the EG group compared with the controls, and this upregulation was reversed in the EG + metformin group. Renal crystal deposition in the EG + metformin group was markedly decreased compared with that in the EG group. Therefore, the results of the study suggest that metformin suppressed urinary crystal deposit formation, possibly by mediating the expression of inflammatory mediators OPN and MCP‑1.

Topics: Animals; Body Weight; Cell Death; Chemokine CCL2; Disease Models, Animal; Dogs; Ethylene Glycol; Humans; Kidney Calculi; Madin Darby Canine Kidney Cells; Male; Metformin; Osteopontin; Oxalates; Rats, Sprague-Dawley; RNA, Messenger; Up-Regulation

The Primary Hyperoxaluria's (PH) are rare autosomal recessive disorders characterized by elevated oxalate production. PH patients suffer recurrent calcium oxalate kidney stone disease, and in severe cases end stage renal disease. Recent evidence has shown that RNA interference may be a suitable approach to reduce oxalate production in PH patients by knocking down key enzymes involved in hepatic oxalate synthesis. In the current study, wild type mice and mouse models of PH1 (AGT KO) and PH2 (GR KO) were treated with siRNA that targets hepatic LDHA. Although siRNA treatment substantially reduced urinary oxalate excretion [75%] in AGT KO animals, there was a relatively modest reduction [32%] in GR KO animals. Plasma and liver pyruvate levels significantly increased with siRNA treatment and liver organic acid analysis indicated significant changes in a number of glycolytic and TCA cycle metabolites, consistent with the known role of LDHA in metabolism. However, siRNA dosing data suggest that it may be possible to identify a dose that limits changes in liver organic acid levels, while maintaining a desired effect of reducing glyoxylate to oxalate synthesis. These results suggest that RNAi mediated reduction of hepatic LDHA may be an effective strategy to reduce oxalate synthesis in PH, and further analysis of its metabolic effects should be explored. Additional studies should also clarify in GR KO animals whether there are alternate enzymatic pathways in the liver to create oxalate and whether tissues other than liver contribute significantly to oxalate production.

Topics: AMP-Activated Protein Kinases; Animals; Disease Models, Animal; Hyperoxaluria, Primary; Lactate Dehydrogenases; Liver; Mice; Mice, Knockout; Oxalates; Pyruvic Acid; RNA Interference; RNA, Small Interfering

Most kidney stones are composed of calcium oxalate, and minor changes in urine oxalate affect the stone risk. Obesity is a risk factor for kidney stones and a positive correlation of unknown etiology between increased body size, and elevated urinary oxalate excretion has been reported. Here, we used obese ob/ob (ob) mice to elucidate the pathogenesis of obesity-associated hyperoxaluria. These ob mice have significant hyperoxaluria (3.3-fold) compared with control mice, which is not due to overeating as shown by pair-feeding studies. Dietary oxalate removal greatly ameliorated this hyperoxaluria, confirming that it is largely enteric in origin. Transporter SLC26A6 (A6) plays an essential role in active transcellular intestinal oxalate secretion, and ob mice have significantly reduced jejunal A6 mRNA (- 80%) and total protein (- 62%) expression. While net oxalate secretion was observed in control jejunal tissues mounted in Ussing chambers, net absorption was seen in ob tissues, due to significantly reduced secretion. We hypothesized that the obesity-associated increase in intestinal and systemic inflammation, as reflected by elevated proinflammatory cytokines, suppresses A6-mediated intestinal oxalate secretion and contributes to obesity-associated hyperoxaluria. Indeed, proinflammatory cytokines (elevated in ob mice) significantly decreased intestinal oxalate transport in vitro by reducing A6 mRNA and total protein expression. Proinflammatory cytokines also significantly reduced active mouse jejunal oxalate secretion, converting oxalate transport from net secretion in vehicle-treated tissues to net absorption in proinflammatory cytokines-treated tissues. Thus, reduced active intestinal oxalate secretion, likely secondary to local and systemic inflammation, contributes to the pathogenesis of obesity-associated hyperoxaluria. Hence, proinflammatory cytokines represent potential therapeutic targets.

Topics: Animals; Antiporters; Caco-2 Cells; Cytokines; Disease Models, Animal; Down-Regulation; Humans; Hyperoxaluria; Inflammation Mediators; Intestinal Absorption; Intestinal Secretions; Jejunum; Male; Mice, Inbred BALB C; Mice, Inbred C57BL; Obesity; Oxalates; Secretory Pathway; Sulfate Transporters

Topics: Animals; Calcium Oxalate; Crystallization; Diet; Disease Models, Animal; Fibrosis; Glomerular Filtration Rate; Humans; Immunoglobulin G; Kidney; Male; Mice; Mice, Inbred C57BL; Nephrocalcinosis; Oxalates; Renal Insufficiency, Chronic; Transforming Growth Factor beta

Primary hyperoxalurias (PHs) are autosomal recessive disorders caused by the overproduction of oxalate leading to calcium oxalate precipitation in the kidney and eventually to end-stage renal disease. One promising strategy to treat PHs is to reduce the hepatic production of oxalate through substrate reduction therapy by inhibiting liver-specific glycolate oxidase (GO), which controls the conversion of glycolate to glyoxylate, the proposed main precursor to oxalate. Alternatively, diminishing the amount of hepatic lactate dehydrogenase (LDH) expression, the proposed key enzyme responsible for converting glyoxylate to oxalate, should directly prevent the accumulation of oxalate in PH patients. Using RNAi, we provide the first in vivo evidence in mammals to support LDH as the key enzyme responsible for converting glyoxylate to oxalate. In addition, we demonstrate that reduction of hepatic LDH achieves efficient oxalate reduction and prevents calcium oxalate crystal deposition in genetically engineered mouse models of PH types 1 (PH1) and 2 (PH2), as well as in chemically induced PH mouse models. Repression of hepatic LDH in mice did not cause any acute elevation of circulating liver enzymes, lactate acidosis, or exertional myopathy, suggesting further evaluation of liver-specific inhibition of LDH as a potential approach for treating PH1 and PH2 is warranted.

Topics: Animals; Disease Models, Animal; Gene Silencing; Humans; Hyperoxaluria, Primary; L-Lactate Dehydrogenase; Liver; Mice; Oxalates; RNA Interference

Increased intestinal absorption of oxalate causes hyperoxaluria, a major risk factor for kidney stone disease. Intestinal colonization of recombinant probiotic bacteria expressing oxalate-degrading gene (OxdC) is an effective therapeutic option for recurrent calcium oxalate (CaOx) stone disease. Therefore, we aimed to develop food-grade probiotic L. plantarum secreting OxdC using lactococcal group II intron, Ll.LtrB and evaluate its oxalate degradation ability in vivo. Male Wistar albino rats were divided into four groups. The rats of group I received normal rat chow and drinking water. Groups II, III and IV rats received 5% potassium oxalate containing diet for 28 days. Groups III and IV rats received L. plantarum and food-grade recombinant L. plantarum respectively from 15 to 28 days. Biochemical parameters and crystalluria were analysed in 24 h urine samples. At the end of experimental period, rats were sacrificed; intestine and kidneys were dissected out for colonization studies and histopathological analysis. Herein, we found that the administration of recombinant probiotics significantly reduced the urinary oxalate, calcium, urea, and creatinine levels in rats of group IV compared to group II. Furthermore, colonization studies indicated that recombinant probiotics have gastrointestinal transit and intestinal colonization ability similar to that of wild-type bacteria. In addition, gene expression studies revealed down-regulation of OPN and KIM-1 among group IV rats. Histopathological analysis showed less evidence of nephrocalcinosis in group IV rats. In conclusion, the study demonstrates that food-grade L. plantarum secreting OxdC is capable of degrading intestinal oxalate and thereby prevent CaOx stone formation in experimental rats.

Topics: Alanine Racemase; Animals; Bacterial Proteins; Calcium; Calcium Oxalate; Carboxy-Lyases; Cell Adhesion Molecules; Creatinine; Disease Models, Animal; Gene Expression; Genes, Bacterial; Genomic Instability; Hyperoxaluria; Intestinal Mucosa; Intestines; Introns; Kidney; Kidney Calculi; Lactobacillus plantarum; Male; Mutagenesis; Nephrocalcinosis; Oxalates; Oxalic Acid; Probiotics; Rats; Rats, Wistar; Recombinant Proteins; RNA-Directed DNA Polymerase; Urea

Primary hyperoxaluria type 1 (PH1) is an inherited disease caused by mutations in alanine-glyoxylate aminotransferase (AGXT). It is characterized by abnormal metabolism of glyoxylic acid in the liver leading to endogenous oxalate overproduction and deposition of oxalate in multiple organs, mainly the kidney. Patients of PH1 often suffer from recurrent urinary tract stones, and finally renal failure. There is no effective treatment other than combined liver-kidney transplantation.. Microinjection was administered to PH1 rats. Urine samples were collected for urine analysis. Kidney tissues were for Western blotting, quantitative PCR, AGT assays and histological evaluation.. In this study, we generated a novel PH1 disease model through CRISPR/Cas9 mediated disruption of mitochondrial localized Agxt gene isoform in rats. Agxt-deficient rats excreted more oxalate in the urine than WT animals. Meanwhile, mutant rats exhibited crystalluria and showed a slight dilatation of renal tubules with mild fibrosis in the kidney. When supplied with 0.4% ethylene glycol (EG) in drinking water, mutant rats excreted greater abundance of oxalate and developed severe nephrocalcinosis in contrast to WT animals. Significantly elevated expression of inflammation- and fibrosisrelated genes was also detected in mutants.. These data suggest that Agxt-deficiency in mitochondria impairs glyoxylic acid metabolism and leads to PH1 in rats. This rat strain would not only be a useful model for the study of the pathogenesis and pathology of PH1 but also a valuable tool for the development and evaluation of innovative drugs and therapeutics.

Topics: Animals; CRISPR-Cas Systems; Disease Models, Animal; Glyoxylates; Hyperoxaluria, Primary; Mitochondria; Nephrocalcinosis; Oxalates; Rats; Rats, Transgenic; Transaminases

Topics: Alcohol Oxidoreductases; Animals; CRISPR-Cas Systems; Disease Models, Animal; Gene Editing; Genetic Therapy; HEK293 Cells; Humans; Hyperoxaluria, Primary; Male; Mice; Nephrocalcinosis; Oxalates

At present, commercially available antiurolithic drugs have more adverse effects than potential therapeutic or preventive effects with chronic use. With this in mind, the present study was designed to assess the antiurolithic effect of olive oil in a mouse model of ethylene glycol (EG)-induced urolithiasis.. Adult albino mice were divided into 6 groups. Group I was fed the vehicle only. Group II was supplemented with 0.75% EG alone in drinking water during the experimental period to initiate deposition of calcium oxalate in kidneys, which leads to urolithiasis in animals. Groups III (olive oil control group) through V were fed olive oil orally at various doses during the experimental period. Group VI received cystone (750 mg/kg). Groups IV-VI additionally received 0.75% EG in drinking water ad libitum. SPSS ver.17.0 was used for statistical analysis.. The study results showed significantly higher levels of serum urea, uric acid, and creatinine (p<0.05) in group II than in groups III-VI and I. Administration of olive oil at different doses restored the elevated serum parameters in groups IV and V compared with group II. Urine and kidney calcium, oxalate, and phosphate levels in groups IV-VI were significantly lower (p<0.05) than in animals with EG-induced urolithiasis (group II). Group V mice showed a significant restoration effect on serum as well as urine and kidney parameters compared with group II.. Supplementation with olive oil (1.7 mL/kg body weight) reduced and prevented the growth of urinary stones, possibly by inhibiting renal tubular membrane damage due to peroxidative stress induced by hyperoxaluria.

Topics: Animals; Calcium; Creatinine; Disease Models, Animal; Dose-Response Relationship, Drug; Ethylene Glycol; Male; Mice; Olive Oil; Oxalates; Phosphates; Urea; Uric Acid; Urolithiasis

Hyperoxaluria and oxalate kidney stones frequently develop after Roux-en-Y gastric bypass (RYGB). Oxalobacter formigenes can degrade ingested oxalate.. Examine the effect of O. formigenes wild rat strain (OXWR) colonization on urinary oxalate excretion and intestinal oxalate transport in a hyperoxaluric RYGB model.. Basic Science Laboratory, United States.. At 21 weeks of age, 28 obese male Sprague-Dawley rats survived Sham (n = 10) or RYGB (n = 18) surgery and were maintained on a 1.5% potassium oxalate, 40% fat diet. At 12 weeks postoperatively, half the animals in each group were gavaged with OXWR. At 16 weeks, percent dietary fat content was lowered to 10%. Urine and stool were collected weekly to determine oxalate and colonization status, respectively. At week 20, [14 C]-oxalate fluxes and electrical parameters were measured in vitro across isolated distal colon and jejunal (Roux limb) tissue mounted in Ussing Chambers.. RYGB animals lost 22% total weight while Shams gained 5%. On a moderate oxalate diet, urinary oxalate excretion was 4-fold higher in RYGB than Sham controls. OXWR colonization, obtained in all gavaged animals, reduced urinary oxalate excretion 74% in RYGB and 39% in Sham and was further augmented by lowering the percentage of dietary fat. Finally, OXWR colonization significantly enhanced basal net colonic oxalate secretion in both groups.. In our model, OXWR lowered urinary oxalate by luminal oxalate degradation in concert with promotion of enteric oxalate elimination. Trials of O. formigenes colonization and low-fat diet are warranted in calcium oxalate stone formers with gastric bypass and resistant hyperoxaluria.

Topics: Animals; Creatinine; Disease Models, Animal; Eating; Feces; Gastric Bypass; Hyperoxaluria; Male; Obesity, Morbid; Oxalates; Oxalobacter formigenes; Random Allocation; Rats, Sprague-Dawley; Weight Loss

To investigate the possible involvement of multidrug resistance-associated protein 1 (MRP-1) and breast cancer resistance protein (BCRP) in the oxalate-induced redistribution of phosphatidylserine (PS) in renal epithelial cell membranes.. A western blot analysis was used to examine the MRP-1 and BCRP expression levels. Surface-expressed PS was detected by the annexin V-binding assay. The cell-permeable fluorogenic probe 2,7-dichlorofluorescein diacetate was used to measure the intracellular reactive oxygen species (ROS) level. A rat model of hyperoxaluria was obtained using 0.5% ethylene glycol and 1.0% ammonium chloride. In addition, certain animals received verapamil (50 mg/kg body weight), which is a common inhibitor of MRP-1 and BCRP. The degree of nephrolithiasis was assessed histomorphometrically using sections stained by Pizzolato method and by measuring the calcium oxalate crystal content in the renal tissue.. Oxalate produced a concentration-dependent increase in the synthesis of MRP-1 and BCRP. Treatment with MK571 and Ko143 (MRP-1- and BCRP-specific inhibitors, respectively) significantly attenuated the oxalate-induced PS externalization. Adding the antioxidant N-acetyl-l-cysteine significantly reduced MRP-1 and BCRP expression. In vivo, markedly decreased nephrocalcinosis was observed compared with that in the rat model of hyperoxaluria without verapamil treatment.. Oxalate induces the upregulation of MRP-1 and BCRP, which act as phospholipid floppases causing PS externalization in the renal epithelial cell membrane. The process is mediated by intracellular ROS production. The ROS-mediated increase in the synthesis of MRP-1 and BCRP can play an important role in hyperoxaluria-promoted calcium oxalate urolithiasis by facilitating phosphatidylserine redistribution in renal epithelial cells.

Topics: Animals; ATP Binding Cassette Transporter, Subfamily G, Member 2; Blotting, Western; Cells, Cultured; Disease Models, Animal; Flow Cytometry; Immunohistochemistry; Male; Multidrug Resistance-Associated Proteins; Nephrolithiasis; Oxalates; Phosphatidylserines; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; RNA; Urothelium

Mechanisms for calcium-based stone formation are not clearly delineated. Porcine are the most anatomically and physiologically congruent mammal to humans. Our objectives were to develop a cost-effective and easily reproducible porcine model for the study of calcium-based nephrolithiasis.. Crossbred male pigs (n = 16) were assigned randomly to one of the following treatments: (1) control; (2) ethylene glycol (EG) + vitamin D (VD); (3) EG + ammonium chloride (AC); (4) EG + gentamicin (G); (5) EG + Lasix; (6) EG + VD + AC; (7) EG + VD + G. Treatments were administered for 28 days; blood and urine were collected on day 0, 14, and 28. At the endpoint of the study, renal tissue was collected for gross and microscopic analysis of crystal stone formation and inflammation.. Stone-forming parameters were observed in serum and urine. For control versus all other treatments, by day 28, serum BUN and creatinine were less (P < 0.01), urinary creatinine, citrate and pH were greater (P < 0.01), and urinary oxalate was less (P < 0.01). Histopathological analysis of H&E staining and stone analysis revealed formation of calcium oxalate stones and crystal formation within the renal cortex and medulla for all animals except control. Nephrotoxicity was observed in one animal from treatment EG + G.. The treatments explored in this experiment provided novel examples of cost-effective porcine models for the study of nephrolithiasis. EG + VD had the strongest indicators of nephrolithiasis without nephrotoxicity.

Topics: Ammonium Chloride; Animals; Blood Urea Nitrogen; Calcium Oxalate; Citric Acid; Creatinine; Disease Models, Animal; Ethylene Glycol; Furosemide; Gentamicins; Hydrogen-Ion Concentration; Kidney Cortex; Kidney Medulla; Male; Nephrolithiasis; Oxalates; Swine; Urine; Vitamin D

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder that has a progression that is closely associated with oxidative stress. It has long been speculated that the reactive oxygen species (ROS) level in AD brains is much higher than that in healthy brains. However, evidence from living beings is scarce. Inspired by the "chemistry of glow stick," we designed a near-IR fluorescence (NIRF) imaging probe, termed CRANAD-61, for sensing ROS to provide evidence at micro- and macrolevels. In CRANAD-61, an oxalate moiety was utilized to react with ROS and to consequentially produce wavelength shifting. Our in vitro data showed that CRANAD-61 was highly sensitive and rapidly responsive to various ROS. On reacting with ROS, its excitation and emission wavelengths significantly shifted to short wavelengths, and this shifting could be harnessed for dual-color two-photon imaging and transformative NIRF imaging. In this report, we showed that CRANAD-61 could be used to identify "active" amyloid beta (Aβ) plaques and cerebral amyloid angiopathy (CAA) surrounded by high ROS levels with two-photon imaging (microlevel) and to provide relative total ROS concentrations in AD brains via whole-brain NIRF imaging (macrolevel). Lastly, we showed that age-related increases in ROS levels in AD brains could be monitored with our NIRF imaging method. We believe that our imaging with CRANAD-61 could provide evidence of ROS at micro- and macrolevels and could be used for monitoring ROS changes under various AD pathological conditions and during drug treatment.

Topics: Alzheimer Disease; Animals; Brain; Curcumin; Disease Models, Animal; Female; Humans; Mice; Mice, Transgenic; Microscopy, Fluorescence, Multiphoton; Molecular Imaging; Molecular Probes; Oxalates; Oxidative Stress; Photons; Plaque, Amyloid; Reactive Oxygen Species; Sensitivity and Specificity; Spectroscopy, Near-Infrared

Primary hyperoxaluria type 1 (PH1), an inherited rare disease of glyoxylate metabolism, arises from mutations in the enzyme alanine-glyoxylate aminotransferase. The resulting deficiency in this enzyme leads to abnormally high oxalate production resulting in calcium oxalate crystal formation and deposition in the kidney and many other tissues, with systemic oxalosis and ESRD being a common outcome. Although a small subset of patients manages the disease with vitamin B6 treatments, the only effective treatment for most is a combined liver-kidney transplant, which requires life-long immune suppression and carries significant mortality risk. In this report, we discuss the development of ALN-GO1, an investigational RNA interference (RNAi) therapeutic targeting glycolate oxidase, to deplete the substrate for oxalate synthesis. Subcutaneous administration of ALN-GO1 resulted in potent, dose-dependent, and durable silencing of the mRNA encoding glycolate oxidase and increased serum glycolate concentrations in wild-type mice, rats, and nonhuman primates. ALN-GO1 also increased urinary glycolate concentrations in normal nonhuman primates and in a genetic mouse model of PH1. Notably, ALN-GO1 reduced urinary oxalate concentration up to 50% after a single dose in the genetic mouse model of PH1, and up to 98% after multiple doses in a rat model of hyperoxaluria. These data demonstrate the ability of ALN-GO1 to reduce oxalate production in preclinical models of PH1 across multiple species and provide a clear rationale for clinical trials with this compound.

Topics: Alcohol Oxidoreductases; Animals; Disease Models, Animal; Gene Silencing; Hyperoxaluria, Primary; Liver; Male; Mice; Oxalates; Primates; Rats; RNA, Messenger; RNAi Therapeutics

Excessive endogenous oxalate synthesis can result in calcium oxalate kidney stone formation and renal failure. Hydroxyproline catabolism in the liver and kidney contributes to endogenous oxalate production in mammals. To quantify this contribution we have infused Wt mice, Agxt KO mice deficient in liver alanine:glyoxylate aminotransferase, and Grhpr KO mice deficient in glyoxylate reductase, with (13)C5-hydroxyproline. The contribution of hydroxyproline metabolism to urinary oxalate excretion in Wt mice was 22±2%, 42±8% in Agxt KO mice, and 36%±9% in Grhpr KO mice. To determine if blocking steps in hydroxyproline and glycolate metabolism would decrease urinary oxalate excretion, mice were injected with siRNA targeting the liver enzymes glycolate oxidase and hydroxyproline dehydrogenase. These siRNAs decreased the expression of both enzymes and reduced urinary oxalate excretion in Agxt KO mice, when compared to mice infused with a luciferase control preparation. These results suggest that siRNA approaches could be useful for decreasing the oxalate burden on the kidney in individuals with Primary Hyperoxaluria.

Topics: Alcohol Oxidoreductases; Animals; Disease Models, Animal; Hydroxyproline; Hyperoxaluria, Primary; Liver; Male; Mice; Mice, Inbred C57BL; Oxalates; Proline Oxidase; RNA, Small Interfering; RNAi Therapeutics

Intrarenal crystal formation activates the Nlrp3 inflammasome in myeloid cells and triggers a profound inflammatory response. Here, we studied whether a specific inhibitor of the Nlrp3 inflammasome, CP-456,773, can prevent kidney fibrosis in a murine model of crystal nephropathy induced by diets rich in oxalate or adenine. Inflammasome activation in renal dendritic cells and the resulting interleukin (IL)-1β and IL-18 production were markedly reduced by CP-456,773 treatment both ex vivo and in vivo. We directly visualized intrarenal inflammasome activation and its inhibition by CP-456,773 in vivo by adoptive transfer of bone marrow cells transduced with interleukin-1β-Gaussia luciferase, a proteolytic luciferase-based reporter for inflammasome activation, into irradiated mice. CP-456,773 treatment strongly attenuated kidney fibrosis when given early in the genesis of crystal nephropathy, but was unable to reverse established crystal-induced fibrosis. The urinary IL-18 concentration appeared to be a useful noninvasive biomarker for renal inflammasome activation. Finally, NLRP3 inhibition did not compromise adaptive immune responses as previously reported for the global inhibition of IL-1 signaling. Thus, early NLRP3 inhibition by CP-456,773 may be an effective treatment for crystal nephropathy. Use of iGLuc transfected cells introduces a novel imaging technique for inflammasome activation in mice.

Topics: Adenine; Adoptive Transfer; Animals; Cells, Cultured; Dendritic Cells; Disease Models, Animal; Fibrosis; Furans; Heterocyclic Compounds, 4 or More Rings; Humans; Immunohistochemistry; Indenes; Inflammasomes; Inflammation; Interleukin-18; Interleukin-1beta; Kidney; Mice; Mice, Inbred C57BL; Mice, Knockout; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Primary Cell Culture; Signal Transduction; Sulfonamides; Sulfones

Oxidative stress is a causal factor and key promoter of urolithiasis associated with renal tubular epithelium cell injury. The present study was designed to investigate the preventive effects of metformin on renal tubular cell injury induced by oxalate and stone formation in a hyperoxaluric rat model. MTT assays were carried out to determine the protection of metformin from oxalate-induced cytotoxicity. The intracellular superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels were measured in vitro. Male Sprague-Dawley rats were divided into control group, ethylene glycol (EG) treated group, and EG + metformin treated group. Oxidative stress and crystal formations were evaluated in renal tissues after 8-week treatment. Metformin significantly inhibited the decrease of the viability in MDCK cells and HK-2 cells induced by oxalate. Besides, metformin markedly prevented the increased concentration of MDA and the decreased tendency of SOD in oxalate-induced MDCK cells and HK-2 cells. In vivo, the increased MDA levels and the reduction of SOD activity were detected in the EG treated group compared with controls, while these parameters reversed in the EG + metformin treated group. Kidney crystal formation in the EG + metformin treated group was decreased significantly compared with the EG treated group. Metformin suppressed urinary crystal deposit formation through renal tubular cell protection and antioxidative effects.

Topics: Animals; Antioxidants; Cell Death; Disease Models, Animal; Dogs; Ethylene Glycol; Humans; Kidney Calculi; Kidney Tubules; Madin Darby Canine Kidney Cells; Male; Malondialdehyde; Metformin; Oxalates; Oxidative Stress; Rats, Sprague-Dawley; Superoxide Dismutase

Clinical and experimental observations indicate a critical role for vascular endothelial growth factor (VEGF), secreted by the retinal pigment epithelium (RPE), in pathological angiogenesis and the development of choroidal neovascularization (CNV) in age-related macular degeneration (AMD). RPE-mediated VEGF expression, leading to angiogenesis, is a major signaling mechanism underlying ocular neovascular disease. Inhibiting this signaling pathway with a therapeutic molecule is a promising anti-angiogenic strategy to treat this disease with potentially fewer side effects. Oxalomalate (OMA) is a competitive inhibitor of NADP

Topics: Angiogenesis Inhibitors; Animals; Cell Line; Cell Movement; Cell Proliferation; Disease Models, Animal; Gene Expression Regulation; Human Umbilical Vein Endothelial Cells; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Macular Degeneration; Mice; Oxalates; Reactive Oxygen Species; Retinal Pigment Epithelium; Signal Transduction; Vascular Endothelial Growth Factor A; Von Hippel-Lindau Tumor Suppressor Protein

Hyperoxaluria significantly increases the risk of calcium oxalate kidney stone formation. Since several bacteria have been shown to metabolize oxalate in vitro, including probiotic bifidobacteria, we focused on the efficiency and possible mechanisms by which bifidobacteria can influence oxalate handling in vivo, especially in the intestines, and compared these results with the reported effects of Oxalobacter formigenes. Bifidobacterium animalis subsp. lactis DSM 10140 and B. adolescentis ATCC 15703 were administered to wild-type (WT) mice and to mice deficient in the hepatic enzyme alanine-glyoxylate aminotransferase (Agxt(-/-), a mouse model of Primary Hyperoxaluria) that were fed an oxalate-supplemented diet. The administration of B. animalis subsp. lactis led to a significant decrease in urinary oxalate excretion in WT and Agxt(-/-) mice when compared to treatment with B. adolescentis. Detection of B. animalis subsp. lactis in feces revealed that 3 weeks after oral gavage with the bacteria 64% of WT mice, but only 37% of Agxt(-/-) mice were colonized. Examining intestinal oxalate fluxes showed there were no significant changes to net oxalate secretion in colonized animals and were therefore not associated with the changes in urinary oxalate excretion. These results indicate that colonization with B. animalis subsp. lactis decreased urinary oxalate excretion by degrading dietary oxalate thus limiting its absorption across the intestine but it did not promote enteric oxalate excretion as reported for O. formigenes. Preventive or therapeutic administration of B. animalis subsp. lactis appears to have some potential to beneficially influence dietary hyperoxaluria in mice.

Topics: Animals; Bifidobacterium; Dietary Supplements; Disease Models, Animal; Hyperoxaluria, Primary; Male; Mice; Mice, Inbred C57BL; Oxalates; Oxalobacter formigenes

Polymorphism of the gene for matrix GLA protein (MGP), a calcification inhibitor, is associated with nephrolithiasis. However, experimental investigations of MGP role in stone pathogenesis are limited. We determined the effect of renal epithelial exposure to oxalate (Ox), calcium oxalate (CaOx) monohydrate (COM) or hydroxyapatite (HA) crystal on the expression of MGP.. MDCK cells in culture were exposed to 0.3, 0.5 or 1 mM Ox and 33, 66 or 133-150 μg/cm(2) of COM/HA for 3-72 h. MGP expression and production were determined by Western blotting and densitometric analysis. Enzyme-linked immunosorbent assay was performed to determine MGP release into the medium. Hyperoxaluria was induced in male Sprague-Dawley rats by feeding hydroxyl-L-proline. Immunohistochemistry was performed to detect renal MGP expression.. Exposure to Ox and crystals led to time- and concentration-dependent increase in expression of MGP in MDCK cells. Cellular response was quicker to crystal exposure than to the Ox, expression being significantly higher after 3-h exposure to COM or HA crystals and more than 6 h of exposure to Ox. MGP expression was increased in kidneys of hyperoxaluric rats particularly in renal peritubular vessels.. We demonstrate increased expression of MGP in renal tubular epithelial cells exposed to Ox or CaOx crystals as well as the HA crystals. The most significant finding of this study is the increased staining seen in renal peritubular vessels of the hyperoxaluric rats, indicating involvement of renal endothelial cells in the synthesis of MGP.

Topics: Animals; Calcium Oxalate; Calcium-Binding Proteins; Cells, Cultured; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Durapatite; Epithelial Cells; Extracellular Matrix Proteins; Hydroxyproline; Hyperoxaluria; Kidney; Madin Darby Canine Kidney Cells; Male; Matrix Gla Protein; Nephrolithiasis; Oxalates; Rats; Rats, Sprague-Dawley; Time Factors

We determined the effect of dietary fat and oxalate on fecal fat excretion and urine parameters in a rat model of Roux-en-Y gastric bypass surgery.. Diet induced obese Sprague-Dawley® rats underwent sham surgery as controls (16), or Roux-en-Y gastric bypass surgery (19). After recovery, rats had free access to a normal calcium, high fat (40%) diet with or without 1.5% potassium oxalate for 5 weeks and then a normal (10%) fat diet for 2 weeks. Stool and urine were collected after each period. Fecal fat was determined by gas chromatography and urine metabolites were evaluated by assay spectrophotometry.. Daily fecal fat excretion remained low in controls on either diet. However, Roux-en-Y gastric bypass rats ingested a food quantity similar to that of controls but had eightfold higher fecal fat excretion (p <0.001) and heavier stools (p = 0.02). Compared to controls, gastric bypass rats on the high fat diet with potassium oxalate had a fivefold increase in urine oxalate excretion (p <0.001), while gastric bypass rats without potassium oxalate had a twofold increase in urine calcium (p <0.01). Lowering dietary fat in gastric bypass rats with potassium oxalate led to a 50% decrease in oxalate excretion (p <0.01), a 30% decrease in urine calcium and a 0.3 U increase in urine pH (p <0.001).. In this Roux-en-Y gastric bypass model high fat feeding resulted in steatorrhea, hyperoxaluria and low urine pH, which were partially reversible by lowering the dietary fat and oxalate content. Roux-en-Y gastric bypass rats on normal fat and no oxalate diets excreted twice as much oxalate as age matched, sham operated controls. Although Roux-en-Y gastric bypass hyperoxaluria appears primarily mediated by gut and diet, secondary causes of oxalogenesis from liver or other mechanisms deserve further exploration.

Topics: Animals; Dietary Fats; Disease Models, Animal; Feces; Gastric Bypass; Hyperoxaluria; Male; Obesity; Oxalates; Postoperative Complications; Random Allocation; Rats; Rats, Sprague-Dawley; Reference Values; Risk Assessment; Steatorrhea; Treatment Outcome; Urinalysis

Oxalate nephropathy with renal failure is caused by multiple disorders leading to hyperoxaluria due to either overproduction of oxalate (primary hyperoxaluria) or excessive absorption of dietary oxalate (enteric hyperoxaluria). To study the etiology of renal failure in crystal-induced kidney disease, we created a model of progressive oxalate nephropathy by feeding mice a diet high in soluble oxalate (high oxalate in the absence of dietary calcium). Renal histology was characterized by intratubular calcium-oxalate crystal deposition with an inflammatory response in the surrounding interstitium. Oxalate nephropathy was not found in mice fed a high oxalate diet that also contained calcium. NALP3, also known as cryopyrin, has been implicated in crystal-associated diseases such as gout and silicosis. Mice fed the diet high in soluble oxalate demonstrated increased NALP3 expression in the kidney. Nalp3-null mice were completely protected from the progressive renal failure and death that occurred in wild-type mice fed the diet high in soluble oxalate. NALP3 deficiency did not affect oxalate homeostasis, thereby excluding differences in intestinal oxalate handling to explain the observed phenotype. Thus, progressive renal failure in oxalate nephropathy results primarily from NALP3-mediated inflammation.

Topics: Animals; Carrier Proteins; Disease Models, Animal; Disease Progression; Female; Genotype; Inflammasomes; Inflammation Mediators; Kidney; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Nephritis; NLR Family, Pyrin Domain-Containing 3 Protein; Oxalates; Phenotype; Renal Insufficiency; Signal Transduction; Time Factors

The purpose of our study was to determine if a hydroxyproline (HP) or gelatin diet could induce long-term hyperoxaluria in the porcine model.. A total of 18 gravid crossbred sows (Large White × Landrace) were randomly allotted into three treatment groups: 5% HP, 10% HP, and gelatin diet. All sows were catheterized 1 day before starting treatment diet. Catheters were left in place for 5 days before being removed. Sows were recatheterized for urine collections on days 11 to 12 and days 21 to 22. Urine was collected for each entire 24-hour period, and urinary oxalate was determined by ion chromatography.. Urinary oxalate concentrations for all three diets peaked within the first 5 days of the diet. The sows fed the 5% HP, 10% HP, and gelatin diets had an early peak in urinary oxalate concentration (mg/L) at day 2 (158% increase), day 5 (316% increase), and day 5 (830% increase), respectively. The day 21 to 22 time points in all three diets demonstrated markedly increased urinary oxalate concentrations in comparison with baseline, with some concentrations higher than the early time point peaks (day 22: 5% HP=1906% increase, P=0.12; 10% HP=640% increase, P=0.02; gelatin=501% increase, P=0.01).. Although both the 10% HP and gelatin diets induce significant short- and long-term hyperoxaluria in the porcine model, the gelatin diet is more cost-effective. The ability to induce long-term hyperoxaluria has important implications in establishing a porcine model for oxalate urolithiasis.

Topics: Animals; Catheterization; Diet; Disease Models, Animal; Gelatin; Hydroxyproline; Hyperoxaluria; Oxalates; Sus scrofa; Time Factors

Acute inflammatory diseases are one of major causes of death in the world and there is great need for developing drug delivery systems that can target drugs to macrophages and enhance their therapeutic efficacy. Poly(amino oxalate) (PAOX) is a new family of fully biodegradable polymer that possesses tertiary amine groups in its backbone and has rapid hydrolytic degradation. In this study, we developed PAOX particles as drug delivery systems for treating acute liver failure (ALF) by taking the advantages of the natural propensity of particulate drug delivery systems to localize to the mononuclear phagocyte system, particularly to liver macrophages. PAOX particles showed a fast drug release kinetics and excellent biocompatibility in vitro and in vivo. A majority of PAOX particles were accumulated in liver, providing a rational strategy for effective treatment of ALF. A mouse model of acetaminophen (APAP)-induced ALF was used to evaluate the potential of PAOX particles using pentoxifylline (PTX) as a model drug. Treatment of PTX-loaded PAOX particles significantly reduced the activity of alanine transaminase (ALT) and inhibited hepatic cell damages in APAP-intoxicated mice. The high therapeutic efficacy of PTX-loaded PAOX particles for ALF treatment may be attributed to the unique properties of PAOX particles, which can target passively liver, stimulate cellular uptake and trigger a colloid osmotic disruption of the phagosome to release encapsulated PTX into the cytosol. Taken together, we believe that PAOX particles are a promising drug delivery candidate for the treatment of acute inflammatory diseases.

Topics: Acetaminophen; Acute Disease; Animals; Cell Line; Chemical and Drug Induced Liver Injury; Cytosol; Disease Models, Animal; Drug Carriers; Drug Delivery Systems; Inflammation; Liver; Macrophages; Mice; Mice, Inbred BALB C; Mononuclear Phagocyte System; Oxalates; Pentoxifylline; Tissue Distribution

Primary hyperoxaluria type I (PH1) is an inborn error of metabolism caused by deficiency of the hepatic enzyme alanine-glyoxylate aminotransferase (AGXT or AGT) which leads to overproduction of oxalate by the liver and subsequent urolithiasis and renal failure. The current therapy largely depends on liver transplantation, which is associated with significant morbidity and mortality. To explore an alternative treatment, we used somatic gene transfer in a mouse genetic model for PH1 (Agxt1KO). Recombinant adeno-associated virus (AAV) vectors containing the human AGXT complementary DNA (cDNA) were pseudotyped with capsids from either serotype 8 or 5, and delivered to the livers of Agxt1KO mice via the tail vein. Both AAV8-AGXT and AAV5-AGXT vectors were able to reduce oxaluria to normal levels. In addition, treated mice showed blunted increase of oxaluria after challenge with ethylene glycol (EG), a glyoxylate precursor. In mice, AGT enzyme activity in whole liver extracts were restored to normal without hepatic toxicity nor immunogenicity for the 50 day follow-up. In summary, this study demonstrates the correction of primary hyperoxaluria in mice treated with either AAV5 or AAV8 vectors.

Topics: Animals; Blotting, Western; Capsid Proteins; Dependovirus; Disease Models, Animal; Ethylene Glycol; Gene Transfer Techniques; Genetic Therapy; Humans; Hyperoxaluria, Primary; Liver; Mice; Mice, Knockout; Nephrocalcinosis; Oxalates; Phenotype; Transaminases; Urolithiasis

Oxalobacter colonization of rat intestine was previously shown to promote enteric oxalate secretion and elimination, leading to significant reductions in urinary oxalate excretion (Hatch et al. Kidney Int 69: 691-698, 2006). The main goal of the present study, using a mouse model of primary hyperoxaluria type 1 (PH1), was to test the hypothesis that colonization of the mouse gut by Oxalobacter formigenes could enhance enteric oxalate secretion and effectively reduce the hyperoxaluria associated with this genetic disease. Wild-type (WT) mice and mice deficient in liver alanine-glyoxylate aminotransferase (Agxt) exhibiting hyperoxalemia and hyperoxaluria were used in these studies. We compared the unidirectional and net fluxes of oxalate across isolated, short-circuited large intestine of artificially colonized and noncolonized mice. In addition, plasma and urinary oxalate was determined. Our results demonstrate that the cecum and distal colon contribute significantly to enteric oxalate excretion in Oxalobacter-colonized Agxt and WT mice. In colonized Agxt mice, urinary oxalate excretion was reduced 50% (to within the normal range observed for WT mice). Moreover, plasma oxalate concentrations in Agxt mice were also normalized (reduced 50%). Colonization of WT mice was also associated with marked (up to 95%) reductions in urinary oxalate excretion. We conclude that segment-specific effects of Oxalobacter on intestinal oxalate transport in the PH1 mouse model are associated with a normalization of plasma oxalate and urinary oxalate excretion in otherwise hyperoxalemic and hyperoxaluric animals.

Topics: Animals; Antiporters; Biological Transport; Cecum; Colon; Disease Models, Animal; Female; Genotype; Hyperoxaluria; Hyperoxaluria, Primary; Intestine, Large; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Oxalates; Oxalobacter formigenes; Phenotype; Sulfate Transporters; Time Factors; Transaminases

Several animal species are used to study calcium oxalate urolithiasis; however, an ideal model has yet to be identified. We used Drosophila as a model organism and fed the flies lithogenic agents such as ethylene glycol, hydroxyl-L-proline, and sodium oxalate. At different times, the Malpighian tubules, the kidney equivalent of insects, were dissected and a polarized light microscope used to highlight the birefringent crystals. Scanning electron microscopy and energy-dispersive X-ray spectroscopy confirmed that the crystal composition was predominately calcium oxalate. Furthermore, administration of potassium citrate successfully reduced the quantity of and modulated the integrity of the ethylene glycol-induced crystals. Thus, the Drosophila model of bio-mineralization produces crystals in the urinary system through many lithogenic agents, permits observation of crystal formation, and is amenable to genetic manipulation. This model may mimic the etiology and clinical manifestations of calcium oxalate stone formation and aid in identification of the genetic basis of this disease.

Topics: Aging; Animals; Calcium Oxalate; Crystallization; Disease Models, Animal; Drosophila melanogaster; Ethylene Glycol; Female; Hydroxyproline; Longevity; Male; Malpighian Tubules; Microscopy, Electron, Scanning; Microscopy, Polarization; Nephrolithiasis; Oxalates; Potassium Citrate; Spectrometry, X-Ray Emission; Triazines; Urolithiasis

The toxicity of Dieffenbachia picta, an ornamental plant, arises from its ability to cause painful edema of oral mucous membranes, buccal ulcerations, and tongue hypertrophy after chewing on the stem or contact with the sap.. We compared the anti-inflammatory effect of eugenol (2-methoxy-4-(2-propenyl)phenol) to different drugs, and investigated the role of oxalate crystals in the development of the inflammation reaction.. Tongue edema in live mice were measured with a digital tachymeter, 2 h after topical application (0.1 mL) or tissue injection (0.05 mL) of D. picta sap. The mice were treated by intraperitoneal or topical application of drugs, 15 min after edema induction. Vascular permeability was quantified based on abdominal skin plasma extravasation of Evans blue dye in response to intradermal administration of D. picta sap. The proteolytic assay was carried out as previously described (Kunitz M. Crystalline soybean trypsin inhibitor. General properties. J Gen Physiol 1947; 30:291-310.).. Arachidonate cascade antagonists and eugenol showed anti-edematogenic effects. High doses of eugenol (50 μg/kg) and sodium cromoglycate (100 mg/kg), but not a combination of the two, inhibited plasma extravasations. The sap without crystals, its methanol extract, or the ethanol-washed crystals in saline-reconstituted solution did not reproduce the tongue edema seen with the original sap. Topical application of 10% sodium bicarbonate completely abolished the tongue edema.. The inflammatory response induced by D. picta may be due to mechanical tissue damage resulting from the physical presence of calcium oxalate crystals. We were, however, unable to exclude the possibility of an insoluble toxicity present within the sap as an etiological agent. We realized that emergency treatment should also aim to inhibit antidromic vasodilation and axon reflex flare, reducing mastocyte degranulation and release of tachykinins from nerve endings. We speculate that eugenol showed better antiedematogenic results because it seems to function not only as a classic non-steroidal anti-inflammatory drug, but also as a local anesthetic, blocking neurotransmission in the damaged tissue.

Topics: Administration, Topical; Angioedema; Animals; Anti-Inflammatory Agents; Araceae; Disease Models, Animal; Drug Interactions; Eugenol; Humans; Injections, Intraperitoneal; Male; Mice; Oxalates; Plant Oils; Tongue; Tongue Diseases

Swine models have proven useful for many different disease processes, especially for urologic research. In this study, we sought to create a model of hyperoxaluria in the adult sow by feeding hydroxyproline (HP). The development of an adult porcine model for calcium oxalate stone disease would represent a significant contribution to stone research as previous animal models have been developed only for rats and baby pigs.. The experiment included a total of 12 multiparous, gestating sows (Large White x Landrace). Sows were randomly allotted to one of the two treatment groups. Treatments involved basal diets that were either control diet (CD) or acidogenic diet (AD). Urine was collected for 6 consecutive days. On days 1 and 2, each sow was fed 2 kg of the assigned basal diet (CD or AD). On days 3, 4, and 5, 200 g of L-hydroxyproline (Wilshire Technologies, Princeton, NJ) was added to each basal diet for all the 12 sows. The HP was evenly mixed with the basal diets before feeding. On day 6, each sow was fed the basal diet originally assigned without HP ( Fig. 1 ). Urine was collected for each entire 24-hour period to control for differences in the diurnal and postprandial variations in the renal handling of oxalate and glycolate.. The addition of HP to the diet increased urinary oxalate excretion. Overall, there was a 192% (CD) and 187% (AD) increase in urinary oxalate between days 1 and 3. The increase peaked on day 3 and gradually returned to baseline by day 6. Student's paired t-test was performed and it confirmed that oxalate on days 3 and 5 was significantly different than baseline (p = 0.009 and p = 0.03, respectively). Urinary glycolate also increased as a result of adding HP to the diet. Overall, there was a 12,340% (CD) and 14,400% (AD) increase in urinary glycolate between days 1 and 3. The increase peaked on day 3 and then declined, although remained more than 10 x greater than baseline at day 6. Student's paired t-test confirmed that glycolate levels on days 3, 5, and 6 were significantly different than baseline (p < 0.001, p = 0.01, and p = 0.03, respectively).. The role of oxalate in the formation of kidney stones cannot be understated. Medical prevention and management of calcium oxalate nephrolithiasis will require a comprehensive understanding of oxalate metabolism in humans. A model for human hyperoxaluria can be reliably created in the adult sow. Such a model is necessary to further our understanding of oxalate metabolism and ultimately aid in the prevention of calcium oxalate calculi.

Topics: Acids; Animals; Diet; Disease Models, Animal; Female; Glycolates; Hydrogen-Ion Concentration; Hydroxyproline; Hyperoxaluria; Oxalates; Sus scrofa

This study investigated the protective effect of the hydro-alcoholic extract of roots of Rubia cordifolia Linn. (HARC) against ethylene glycol induced urolithiasis and its possible underlying mechanisms using male Wistar albino rats. Ethylene glycol feeding resulted in hyperoxaluria, hypocalciuria as well as increased renal excretion of phosphate. Supplementation with HARC significantly prevented change in urinary calcium, oxalate and phosphate excretion dose-dependently. The increased calcium and oxalate levels and number of calcium oxalate crystals deposits in the kidney tissue of calculogenic rats were significantly reverted by HARC treatment. The HARC supplementation also prevents the impairment of renal functions.. Indicate that the HARC can protect against ethylene glycol induced urolithiasis as it reduced and prevented the growth of urinary stones. Therefore, HARC is helpful to prevent the recurrence of the disease as it showed its effect on early stages of stone development. The mechanism underlying this effect is mediated possibly through an antioxidant, nephroprotection and its effect on the urinary concentration of stone-forming constituents and risk factors.

Topics: Animals; Antioxidants; Calcium; Disease Models, Animal; Ethanol; Ethylene Glycol; Hyperoxaluria; Kidney; Lipid Peroxidation; Male; Oxalates; Plant Extracts; Plant Roots; Rats; Rats, Wistar; Rubia; Urinalysis; Urination; Urolithiasis; Water

Renal protection and antiurolithiasic effects of two extracts of Paronychia argentea (PA), a traditional Algerian plant commonly known as Algerian tea, were evaluated. This study was carried out to determine whether the aqueous extract (APA) or the butanolic extract (BPA) of aerial parts could prevent or reduce calculi aggregation in experimental calcium oxalate (Ox) nephrolithiasis in Wistar rats.. The two extracts (APA and BPA) were administrated orally and daily, during 28 days to nephrolithiasic treated rats at the dose of 250, 500 mg/kg b.w. and 10, 20mg/kg b.w. respectively. Body weight, renal index, liver index, serum level of creatinine, uric acid, urea, K(+), Ca(2+), Mg(2+), Na(+) and transaminase (alanine aminotransferase, ALT; aspartate aminotransferase, AST), phosphatase alkaline activity (PAL) were evaluated following the 28 days treatment in rats. In addition histopathological changes in kidney and liver were stained in hematoxylin eosin (HE).. The effect of the extracts could be advantageous in preventing urinary stone retention by reducing renal necrosis and thus inhibit crystal retention. In contradiction with APA, the two doses of BPA attenuated elevation in the serum creatinine (p<0.01) and blood urea levels (p<0.01) (nephroprotective effect). However, the increase in ALT (27%) and PAL (31-51%) serum levels and in the relative liver weights (p<0.01) in the groups treated with doses of APA may indicate that this extract has not a hepatoprotective effect against oxalate toxicity.. The presented data indicate that administration of the butanolic extract of aerial parts to rats with NaOx induced lithiasis, and reduced and prevented the growth of urinary stones in experimental calcium oxalate nephrolithiasis in Wistar rats.

Topics: Alanine Transaminase; Alkaline Phosphatase; Animals; Calcium Oxalate; Caryophyllaceae; Creatinine; Disease Models, Animal; Kidney; Kidney Calculi; Liver; Male; Necrosis; Nephrolithiasis; Organ Size; Oxalates; Phytotherapy; Plant Components, Aerial; Plant Extracts; Rats; Rats, Wistar; Urea

Urolithiasis, the process of formation of stones in the kidneys and urinary tract, is the major clinical manifestation of hyperoxaluria. Ethylene glycol feeding resulted in hyperoxaluria with increased renal excretion of oxalate, sodium, calcium and phosphate and a decrease in the excretion of magnesium. Supplementation with an aqueous and alcoholic extract of the leaves of Salvadora persica significantly reduced elevated urinary oxalate levels, indicating a regenerative action on endogenous oxalate synthesis. The deposition of stone-forming constituents in the kidneys of calculogenic rats was also significantly lowered by curative and preventive treatments with the aqueous and alcoholic extracts of Salvadora persica. The high serum creatinine level observed in ethylene glycol-treated rats was also reduced following treatment with the extracts. Histopathological findings showed signs of improvement after treatment with the extracts. These observations led to the conclusion that the aqueous and alcoholic extracts of the leaves of Salvadora persica are endowed with antiurolithiatic properties.

Topics: Animals; Creatinine; Disease Models, Animal; Ethylene Glycol; Female; Kidney Calculi; Male; Mice; Oxalates; Plant Extracts; Plant Leaves; Rats; Rats, Wistar; Risk Factors; Salvadoraceae; Solvents; Toxicity Tests, Acute; Urolithiasis

Hyperoxaluria is a major risk factor for recurrent urolithiasis and nephrocalcinosis. We tested an oral therapy with a crystalline, cross-linked formulation of oxalate-decarboxylase (OxDc-CLEC) on the reduction of urinary oxalate and decrease in the severity of kidney injury in two models: AGT1 knockout mice (AGT1KO) in which hyperoxaluria is the result of an Agxt gene deficiency, and in AGT1KO mice challenged with ethylene glycol (EG).. Four different doses of OxDc-CLEC mixed with the food, or placebo were given to AGT1KO mice (200 mg/day, n = 7) for 16 days and to EG-AGT1KO mice (5, 25, and 80 mg, n = 11) for 32 days.. Oral therapy with 200 mg OxDc-CLEC reduced both urinary (44%) and fecal oxalate (72%) in AGT1KO mice when compared to controls. Similarly, in EG-AGT1KO mice, each of the three doses of OxDc-CLEC produced a 30-50% reduction in hyperoxaluria. A sustained urinary oxalate reduction of 40% or more in the 80 mg group led to 100% animal survival and complete prevention of nephrocalcinosis and urolithiasis.. These data suggest that oral therapy with OxDc-CLEC may reduce hyperoxaluria, prevent calcium oxalate nephrocalcinosis and urolithiasis, and can represent a realistic option for the treatment of human hyperoxaluria, independent of cause.

Topics: Administration, Oral; Amino Acid Transport Systems; Animals; Carboxy-Lyases; Chemistry, Pharmaceutical; Crystallization; Disease Models, Animal; Ethylene Glycol; Feces; Hyperoxaluria; Kidney; Male; Mice; Mice, Knockout; Nephrocalcinosis; Oxalates; Peptide Hydrolases; Urolithiasis

Oxaliplatin is a key drug in the treatment of advanced metastatic colorectal cancer, but it causes acute peripheral neuropathy (acral paresthesias triggered by exposure to cold) and chronic neuropathy (abnormal of sensory and motor dysfunction). Oxaliplatin is metabolized to oxalate and dichloro(1,2-diaminocyclohexane)platinum (Pt(dach)Cl(2)). Although the chelating of Ca(2+) with oxalate eliminated from oxaliplatin is thought as one of the reasons for the neuropathy, there is little behavioral evidence. In this study, we investigated the involvement of oxalate in the oxaliplatin-induced peripheral neuropathy in rats. Oxaliplatin (4mg/kg, i.p., twice a week) induced cold hyperalgesia/allodynia (cold-plate and acetone tests) in the early phase, and mechanical allodynia (von Frey test) in the late phase. Oxalate (1.3mg/kg, i.p., twice a week) induced the cold hyperalgesia/allodynia in the early phase, but did not induce the mechanical allodynia. On the other hand, Pt(dach)Cl(2) (3.8mg/kg, i.p., twice a week) induced the mechanical allodynia in the late phase, but did not induce the cold hyperalgesia/allodynia. The pre-administration of calcium or magnesium (0.5mmol/kg, i.v.) before oxaliplatin or oxalate prevented the cold hyperalgesia but not mechanical allodynia. However, the treatment with calcium or magnesium after the development of neuropathy could not attenuate the cold hyperalgesia or mechanical allodynia. These findings suggest the involvement of oxalate in oxaliplatin-induced cold hyperalgesia but not mechanical allodynia, and usefulness of prophylactic treatments with calcium and magnesium on the acute peripheral neuropathy.

Topics: Animals; Antineoplastic Agents; Body Weight; Calcium; Cold Temperature; Disease Models, Animal; Dose-Response Relationship, Drug; Hyperalgesia; Magnesium; Male; Neuralgia; Organoplatinum Compounds; Oxalates; Oxaliplatin; Pain Measurement; Pain Threshold; Physical Stimulation; Rats; Rats, Sprague-Dawley

The present study was undertaken to explore the efficiency of the pentacyclic triterpene lupeol (1) and its ester derivative, lupeol linoleate (2), in experimental hyperoxaluria. Hyperoxaluria was induced in male Wistar rats with 0.75% ethylene glycol (EG) in drinking water for 28 days. Hyperoxaluric animals were supplemented orally with 1 and 2 (50 mg/kg body wt/day) throughout the experimental period of 28 days. The renal enzymes were assayed as markers of renal tissue integrity. The redox status and oxalate metabolism in animals under oxalate overloading was also assessed. Microscopic analysis was done to investigate the abnormalities associated with oxalate exposure in renal tissues. Increase in oxidative milieu in hyperoxaluria was evident by increased lipid peroxidation (LPO) and decreased enzymic and nonenzymic antioxidants. Decrease in the activities of renal enzymes exemplified the damage induced by oxalate, which correlated positively with increased LPO and increased oxalate synthesis. Renal microscopic analysis further emphasized the oxalate-induced damage. These abnormal biochemical and histological aberrations were attenuated with test compound treatment, with 2 more effective than 1. From the present study, it can be concluded that 1 and 2 may serve as candidates for alleviating oxalate toxicity.

Topics: Administration, Oral; Animals; Disease Models, Animal; Ethylene Glycol; Hyperoxaluria; Kidney Calculi; Lipid Peroxidation; Male; Oxalates; Pentacyclic Triterpenes; Rats; Rats, Wistar; Triterpenes; Urolithiasis

The interactions between crystals and renal tubular cells are important factors in urolithiasis formation. Moreover, some reports have suggested the involvement of renal tubular cell injury in crystal-cell interaction processes. Atorvastatin, which is a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A, is prescribed to decrease high cholesterol levels, and it has anti-inflammation and anti-oxidization activities. Atorvastatin is also reported to control transforming growth factor-beta1 expression. We investigated whether atorvastatin can prevent renal tubular cell injury by oxalate and inhibit renal crystal retention.. Ten-week-old specific pathogen-free male Sprague-Dawley rats were used. Atorvastatin (2 mg/kg) in 0.5% carboxymethyl cellulose was administered orally daily for 2 weeks. The rats were separated into 4 experimental groups, including group 1--water and 0.5% carboxymethyl cellulose daily, group 2--water and atorvastatin in 0.5% carboxymethyl cellulose daily, group 3--1% ethylene glycol dissolved in water, 0.5 mug vitamin D3 dissolved in 1 ml salad oil and 0.5% carboxymethyl cellulose daily, and group 4--1% ethylene glycol dissolved in water, 0.5 microg vitamin D3 dissolved in 1 ml salad oil and atorvastatin in 0.5% carboxymethyl cellulose daily. The ethylene glycol model of hyperoxaluria and the effect of atorvastatin treatment were analyzed in groups 1 to 4. Urine samples were collected every 24 hours in metabolic cages and analyzed immediately or stored at -70C until analysis. The rats were sacrificed after 2 weeks and the kidneys were removed for further examination. We measured urinary N-acetyl glucosaminidase levels as a biomarker of renal tubular cell injury and urinary 8-OHdG as a biomarker of oxidative stress in 24-hour urine samples. Removed kidneys were used for quantitative analysis of the superoxide dismutase level and the detection of apoptosis. Finally, we measured the amount of crystal deposits in renal tubular cells.. Urinary N-acetyl glucosaminidase and 8-OHdG levels were decreased significantly by atorvastatin treatment in this stone forming rat model. Atorvastatin treatment increased the superoxide dismutase level and inhibited the degree of renal tubular cell N-acetyl glucosaminidase compared with stone forming control group 3. A decrease in renal crystal retention was noted when excised kidneys were evaluated following atorvastatin treatment.. Atorvastatin was found to have inhibitory effects on the renal tubular cell injury and oxidative stress caused by oxalate and crystals. Atorvastatin inhibited renal crystal retention. We believe that atorvastatin could help prevent and treat renal crystal formation.

Topics: Animals; Apoptosis; Atorvastatin; Biopsy, Needle; Disease Models, Animal; Heptanoic Acids; Immunohistochemistry; Kidney Calculi; Kidney Tubules; Male; Oxalates; Oxidative Stress; Probability; Pyrroles; Random Allocation; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; Sensitivity and Specificity; Statistics, Nonparametric; Superoxide Dismutase; Urinalysis

This study was done to resolve published discrepancies in oxalate excretion between humans and rats and to characterize oxalate partitioning in rats during persistent severe hyperoxaluria, such as that seen in many bariatric patients. Osmotic minipumps dispensing 360 micromole/day KOx + 3.9 +/- 0.14 microCi/day (14)C-oxalate were implanted subcutaneously. All excreta were collected. Rats were killed on day 13 and carcasses were dissected, ground, dissolved in HCl, and subjected to scintillation counting, and 92.1 +/- 3.9% of total oxalate administered was recovered. This was partitioned among the skin complex (38.2 +/- 7.7%), carcass complex (24.5 +/- 5.9%), and excreta (29.5 +/- 1.9%). The distribution of oxalate in the skin and carcass complexes led us to infer that only 29.5 +/- 1.9% of the administered oxalate entered the circulation. Of the circulated oxalate, 98.4 +/- 0.4% was excreted (total urine 78.9 +/- 1.7%; raw feces 21.0 +/- 1.7%). Thus, most oxalate that does enter the circulation is promptly excreted in rats, as in humans. Consequently, even after a large, persistent oxalate challenge, very little oxalate had accumulated in the internal organs, muscle, and skeleton. Unlike humans, however, rats excrete a significant fraction of oxalate in the feces.

Topics: Animals; Bone and Bones; Carbon Radioisotopes; Disease Models, Animal; Feces; Hyperoxaluria; Infusion Pumps; Male; Muscle, Skeletal; Oxalates; Rats; Rats, Sprague-Dawley; Skin; Viscera

A series of substituted N-methylisonicotinamidine (2a-f), N-methylpyrazine-2-carboxamidine (2g-i) derivatives were synthesized by reaction of amidine derivatives (1a-i) with methyl iodide in presence of triethylamine. Five-membered condensed dihydroimidazolylbenzenesulfonamide derivatives (3a-i) were obtained by the reaction of amidine derivatives (1a-i) with acylating agent oxalyl chloride. All the compounds, i.e. 2a-i and 3a-i were purified by crystallization. Structures of all the synthesized compounds are supported by correct IR, (1)H NMR, mass spectral and analytical data. Anti-inflammatory activity evaluation was carried out using carrageenan-induced paw oedema assay and compounds 2e, 3a and 3d exhibited good anti-inflammatory activity (44%, 31% and 37% activity at 50 mg/kg p.o., respectively). Analgesic activity evaluation was carried out using acetic acid writhing assay and compounds 2a and 3f gave 75% activity each at 100 mg/kg p.o.; on the other hand compounds 3a and 3d exhibited 60% analgesic activity each at 50 mg/kg p.o. Compounds 3a and 3d exhibited good anti-inflammatory and analgesic activities.

Topics: Administration, Oral; Amidines; Analgesics; Animals; Anti-Inflammatory Agents, Non-Steroidal; Carrageenan; Chlorides; Crystallography, X-Ray; Cyclization; Disease Models, Animal; Drug Evaluation, Preclinical; Edema; Female; Male; Mice; Models, Molecular; Molecular Structure; Oxalates; Pain; Pain Measurement; Rats; Rats, Wistar; Stereoisomerism; Structure-Activity Relationship

In order to compare the effects of several experimental renal calcium oxalate stones formation models in rats and to find a simple and convenient model with significant effect of calcium oxalate crystals deposition in the kidney, several rat models of renal calcium oxalate stones formation were induced by some crystal-inducing drugs (CID) including ethylene glycol (EG), ammonium chloride (AC), vitamin D(3)[1alpha(OH)VitD(3), alfacalcidol], calcium gluconate, ammonium oxalate, gentamicin sulfate, L-hydroxyproline. The rats were fed with drugs given singly or unitedly. At the end of experiment, 24-h urines were collected and the serum creatinine (Cr), blood urea nitrogen (BUN), the extents of calcium oxalate crystal deposition in the renal tissue, urinary calcium and oxalate excretion were measured. The serum Cr levels in the stone-forming groups were significantly higher than those in the control group except for the group EG+L-hydroxyproline, group calcium gluconate and group oxalate. Blood BUN concentration was significantly higher in rats fed with CID than that in control group except for group EG+L-hydroxyproline and group ammonium oxalate plus calcium gluconate. In the group of rats administered with EG plus Vitamin D(3), the deposition of calcium oxalate crystal in the renal tissue and urinary calcium excretion were significantly greater than other model groups. The effect of the model induced by EG plus AC was similar to that in the group induced by EG plus Vitamin D(3). EG plus Vitamin D(3) or EG plus AC could stably and significantly induced the rat model of renal calcium oxalate stones formation.

Topics: Ammonium Chloride; Animals; Blood Urea Nitrogen; Calcium; Calcium Gluconate; Calcium Oxalate; Creatinine; Crystallization; Disease Models, Animal; Ethylene Glycol; Gentamicins; Hydroxycholecalciferols; Hydroxyproline; Kidney; Kidney Calculi; Magnesium; Male; Microscopy, Polarization; Oxalates; Phosphorus; Random Allocation; Rats; Rats, Wistar

The current work was designed to study the potential of N-acetylcysteine (NAC) in modulating hyperoxaluric manifestations induced by acute oxalate dose in rat liver. Hyperoxaluric conditions were induced by giving a single dose of sodium oxalate (70 mg/kg body weight) in one group, and in the other group, hyperoxaluric rats were administered NAC (200 mg/kg body weight) after 30 min of the oxalate dose. After 12 h of the above treatment, blood was taken from the orbital sinus for testing serum oxalate, and animals were sacrificed. To exploit the potential of NAC, various oxidative stress parameters [lipid peroxidation (LP) and activity of antioxidant enzymes], lipid content, and histologic analysis of rat liver were performed. The increased level of LP and activities of superoxide dismutase and catalase in hyperoxaluric rats were restored after NAC treatment. Not only the decreased amount of total lipids and phospholipids but also the increased ratio of cholesterol/phospholipid (showing decreased membrane fluidity) in hyperoxaluric rats were balanced by NAC treatment. Further restored histologic changes of liver tissue confirmed the protective antioxidant effects of the given drug. Thus, N-acetylcysteine being an extraneous antioxidant showed curative properties toward hyperoxaluric manifestations in liver.

Topics: Acetylcysteine; Animals; Catalase; Disease Models, Animal; Free Radical Scavengers; Hyperoxaluria; Lipid Metabolism; Lipid Peroxidation; Liver; Liver Diseases; Male; Membrane Fluidity; Oxalates; Oxidative Stress; Rats; Rats, Wistar; Superoxide Dismutase

Kidney stones are known to haunt humanity for centuries and increase in oxalate is a predominant risk factor for stone formation. The present study was initiated with a notion to study the oxidative and nitrosative stress on erythrocytes under oxalate stress and the putative role of sulphated polysaccharides. Hyperoxaluria was induced in two groups by the administration of 0.75% ethylene glycol in drinking water for 28 days and one of them was treated with sulphated polysaccharides from Fucus vesiculosus from the 8th day to the end of the experimental period of 28 days at a dose of 5 mg/kg body weight subcutaneously. Control and drug control (sulphated polysaccharides alone) were also included in the study. Glycolic and glyoxylic acid levels of urine were analyzed as an index of hyperoxaluria. The plasma enzymic markers of cellular integrity, redox status of red blood cells, osmotic fragility, and (14)C-oxalate binding were investigated. Urine and plasma nitric oxide metabolites, expression of inducible nitric oxide synthase protein, and mRNA were assessed in kidney to evaluate the nitrosative stress. Increased levels of glycolic and glyoxylic acid in urine indicated the prevalence of hyperoxaluria in ethylene glycol-administered groups. Plasma aspartate and alanine transaminase were not altered, but alkaline phosphatase and lactate dehydrogenase of hyperoxaluric group were increased indicating tissue damage. Activities of antioxidant enzymes were decreased, whereas erythrocyte membrane lipid peroxidation was increased in hyperoxaluric rats. Moreover, an altered fragility with an increase in oxalate binding activity was observed in hyperoxaluric group. Increase in nitric oxide metabolites levels in urine and plasma along with an increase in expression of inducible nitric oxide synthase protein and mRNA in kidney were observed in hyperoxaluric rats. Administration of sulphated polysaccharides to hyperoxaluric rats averted the abnormal increase in urinary glycolic and glyoxylic acid levels and enzyme activities, decreased lipid peroxidation, and increased the activities of antioxidant enzymes. Furthermore, increased nitrosative stress accompanying hyperoxaluria was also normalized on sulphated polysaccharides treatment. To conclude, sulphated polysaccharide administration was able to maintain the integrity of erythrocyte membrane and decrease the damage to erythrocytes in hyperoxaluria.

Topics: Animals; Biomarkers; Carbon Radioisotopes; Disease Models, Animal; Erythrocytes; Ethylene Glycol; Fucus; Glycolates; Glyoxylates; Hyperoxaluria; Kidney; Male; Nitric Oxide Donors; Nitrosation; Osmotic Fragility; Oxalates; Oxidative Stress; Plant Extracts; Polysaccharides; Rats; Rats, Wistar; Sulfates

Calcium oxalate monohydrate (COM) crystals are the commonest component of kidney stones. Oxalate and COM crystals in renal cells are thought to contribute to pathology via prooxidant events. Using an in vivo rat model of crystalluria induced by hyperoxaluria plus hypercalciuria [ethylene glycol (EG) plus 1,25-dihydroxycholecalciferol (DHC)], we measured glutathione and energy homeostasis of kidney mitochondria. Hyperoxaluria or hypercalciuria without crystalluria was also investigated. After 1-3 wk of treatment, kidney cryosections were analyzed by light microscopy. In kidney subcellular fractions, glutathione and antioxidant enzymes were measured. In mitochondria, oxygen consumption and superoxide formation as well as cytochrome c content were measured. EG plus DHC treatment increased formation of renal birefringent crystal. Histology revealed increased renal tubular pathology characterized by obstruction, distension, and interstitial inflammation. Crystalluria at all time points led to oxidative stress manifest as decreased cytosolic and mitochondrial glutathione and increased activity of the antioxidant enzymes glutathione reductase and -peroxidase (mitochondria) and glucose-6-phosphate dehydrogenase (cytosol). These changes were followed by a significant decrease in mitochondrial cytochrome c content at 2-3 wk, suggesting the involvement of apoptosis in the renal pathology. Mitochondrial oxygen consumption was severely impaired in the crystalluria group without increased mitochondrial superoxide formation. Some of these changes were also evident in hyperoxaluria at week 1 but were absent at later times and in all calciuric groups. Our data indicate that impaired electron flow did not cause superoxide formation; however, mitochondrial dysfunction contributes to pathological events when tubular crystal-cell interactions are uncontrolled, as in kidney stones disease.

Topics: Animals; Calcium; Calcium Oxalate; Cytochromes c; Cytosol; Disease Models, Animal; Energy Metabolism; Glutathione; Kidney; Kidney Calculi; Male; Mitochondria; Oxalates; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reference Values

The rat kidney H1 oxalate binding protein was isolated and purified. Oxalate binds exclusively with H1B fraction of H1 histone. Oxalate binding activity is inhibited by lysine group modifiers such as 4',4'-diisothiostilbene-2,2-disulfonic acid (DIDS) and pyridoxal phosphate and reduced in presence of ATP and ADP. RNA has no effect on oxalate binding activity of H1B whereas DNA inhibits oxalate binding activity. Equilibrium dialysis method showed that H1B oxalate binding protein has two binding sites for oxalate, one with high affinity, other with low affinity. Histone H1B was modeled in silico using Modeller8v1 software tool since experimental structure is not available. In silico interaction studies predict that histone H1B-oxalate interaction take place through lysine121, lysine139, and leucine68. H1B oxalate binding protein is found to be a promoter of calcium oxalate crystal (CaOx) growth. A 10% increase in the promoting activity is observed in hyperoxaluric rat kidney H1B. Interaction of H1B oxalate binding protein with CaOx crystals favors the formation of intertwined calcium oxalate dehydrate (COD) crystals as studied by light microscopy. Intertwined COD crystals and aggregates of COD crystals were more pronounced in the presence of hyperoxalauric H1B.

Topics: Amino Acid Sequence; Animals; Binding Sites; Computational Biology; Computer Simulation; Disease Models, Animal; Histones; Male; Models, Chemical; Models, Molecular; Molecular Conformation; Molecular Sequence Data; Nucleocytoplasmic Transport Proteins; Oxalates; Protein Binding; Protein Interaction Mapping; Rats; Rats, Wistar; Sequence Analysis, Protein; Urinary Calculi

A number of animal models have been developed to investigate calcium oxalate (CaOx) nephrolithiasis. Ethylene glycol (EG)-induced hyperoxaluria in rats is most common, but is criticized because EG and some of its metabolites are nephrotoxic and EG causes metabolic acidosis. Both oxalate (Ox) and CaOx crystals are also injurious to renal epithelial cells. Thus, it is difficult to distinguish the effects of EG and its metabolites from those induced by Ox and CaOx crystals. This study was performed to investigate hydroxy-L-proline (HLP), a common ingredient of many diets, as a hyperoxaluria-inducing agent. In rats, HLP has been shown to induce CaOx nephrolithiasis in only hypercalciuric conditions. Five percent HLP mixed with chow was given to male Sprague-Dawley rats for 63 days, resulting in hyperoxaluria, CaOx crystalluria, and nephrolithiasis. Crystal deposits were surrounded by ED-1-positive inflammatory cells. Cell injury and death was followed by regeneration, as suggested by an increase in proliferating cell nuclear antigen-positive cells. Both osteopontin (OPN) and CD44 were upregulated. Staining for CD44 and OPN was intense in cells lining the tubules that contained crystals. Along with a rise in urinary Ox and lactate dehydrogenase, there were significant increases in 8-isoprostane and hydrogen peroxide excretion, indicating that the oxidative stress induced cell injury. Thus, HLP-induced hyperoxaluria alone can induce CaOx nephrolithiasis in rats.

Topics: Animals; Calcium; Calcium Oxalate; Creatinine; Dinoprost; Disease Models, Animal; Gene Expression Regulation; Hyaluronan Receptors; Hydrogen Peroxide; Hydroxyproline; Hyperoxaluria; Immunohistochemistry; Kidney Calculi; Kidney Tubules; L-Lactate Dehydrogenase; Male; Osteopontin; Oxalates; Rats; Rats, Sprague-Dawley; Sialoglycoproteins

Our understanding of nitrosative stress in the process of urolithiasis is far from complete. Earlier studies carried out in our laboratory demonstrate the presence of nitrated THP in stone formers, l-arginine (l-arg) a precursor of nitric oxide (NO), attenuates the endothelial dysfunction caused by reactive nitrogen species. We investigated the role of l-arg in ethylene glycol (EG)-induced urolithic rat model and observed its antilithic and antioxidative properties.. Hyperoxaluria was induced using 0.75% EG in drinking water. l-arg [1.25 g/kg body weight] was given orally for a period of 28 days.. EG-treated rats showed significant loss in body weight and increase in the activities of oxalate synthesizing enzymes such as glycollic acid oxidase in liver. Lactate dehydrogenase activity in liver and kidney was increased. The activity of the free radical producing enzyme xanthine oxidase, tissue oxalate and calcium levels were significantly increased in EG-treated rats. Depletion in the antioxidant enzymes, membrane bound ATPases and thiol status was observed in these rats. l-arg co-supplementation to EG-treated rats maintained the activities of the oxalate synthesizing enzymes and free radical producing enzymes with in the normal range. Tissue oxalate and calcium levels were also maintained near normal in l-arg treated hyperoxaluric rats. l-arg, by its cytoprotective effect, maintained the thiol status, thereby preserving the activities of the membrane bound ATPases and preventing proteinuria and subsequent weight loss in EG-treated rats.. l-arg feeding prevents the retention of calcium oxalate crystals in hyperoxaluric rats by way of protecting the renal cells from oxidative injury and also by providing a second line of defense through the normalization of the oxalate metabolism. It reduces the risk of stone formation, by curtailing free radicals and hyperoxaluria as both of them have to work in close association to form stones.

Topics: Animals; Antioxidants; Arginine; Body Weight; Dietary Supplements; Disease Models, Animal; Ethylene Glycol; Free Radicals; Hyperoxaluria; Kidney; L-Lactate Dehydrogenase; Liver; Male; Nitrosation; Oxalates; Oxidative Stress; Oxidoreductases; Rats; Rats, Wistar; Uricosuric Agents; Urinary Calculi

Ethylene glycol (EG) consumption is commonly employed as an experimental regimen to induce hyperoxaluria in animal models of calcium oxalate nephrolithiasis. This approach has, however, been criticized because EG overdose induces metabolic acidosis in humans. We tested the hypothesis that EG consumption (0.75% in drinking water for 4 wk) induces metabolic acidosis by comparing arterial blood gases, serum electrolytes, and urinary chemistries in five groups of Sprague-Dawley rats: normal controls (CON), those made hyperoxaluric (HYP) with EG administration, unilaterally nephrectomized controls (UNI), unilaterally nephrectomized rats fed EG (HRF), and a metabolic acidosis (MA) reference group imbibing sweetened drinking water (5% sucrose) containing 0.28 M NH4Cl. Arterial pH, plasma bicarbonate concentrations, anion gap, urinary pH, and the excretion of titratable acid, ammonium, phosphate, citrate, and calcium in HYP rats were not significantly different from CON rats, indicating that metabolic acidosis did not develop in HYP rats with two kidneys. Unilateral nephrectomy alone (UNI group) did not significantly affect arterial pH, plasma bicarbonate, anion gap, or urinary pH compared with CON rats; however, HRF rats exhibited some signs of a nascent acidosis in having an elevated anion gap, higher phosphate excretion, lower urinary pH, and an increase in titratable acid. Frank metabolic acidosis was observed in the MA rats: decreased arterial pH and plasma HCO3(-) concentration with lower urinary pH and citrate excretion with elevated excretion of ammonium, phosphate and, hence, titratable acid. We conclude that metabolic acidosis does not develop in conventional EG treatments but may ensue with renal insufficiency resulting from an oxalate load.

Topics: Acidosis; Animals; Carbon Dioxide; Disease Models, Animal; Electrolytes; Ethylene Glycol; Hyperoxaluria; Kidney Calculi; Kidney Failure, Chronic; Kidney Function Tests; Male; Oxalates; Oxygen; Rats; Rats, Sprague-Dawley

Most renal stones in humans are composed of calcium oxalate. An increase in urinary oxalate levels has been shown to result in renal epithelial cell injury and crystal retention. However, the underlying mechanisms are unclear. Although the localization of primary stone formation and the associated cells playing the pivotal role in stone formation are still unknown, renal epithelial cells and interstitial cells seem to be involved in this process. The aim of this study was to evaluate the effects of oxalate on distinct renal epithelial and endothelial cells as well as fibroblasts. The first part focused on the toxicity of oxalate on the cells and a potential time- and dose-dependency. In the second part, renal epithelial cells were cultured in a two-compartment model to examine the vulnerability of the tubular or basolateral side to oxalate. LLCPK1, MDCK, renal fibroblast and endothelial cell lines were cultured under standard conditions. In part 1, cells were grown in standard culture flasks until confluent layers were achieved. Sodium oxalate was delivered at final concentrations of 1, 2 and 4 mM to either the apical or basolateral side (plain medium was delivered to the contralateral side). Cell survival was assessed microscopically by trypan blue staining after 1, 2 and 4 h. The influence of oxalate on proliferation and apoptosis induction was also investigated. In the second part, MDCK and LLCPK1 cells were grown in 6-well plates until confluent layers were achieved. Sodium oxalate at the above concentrations was applied, to either the apical or basolateral side and plain medium was delivered to the opposite side. The same protocol was then followed as in part 1. Part 1: sodium oxalate led to a time- and concentration-dependent decline in cell survival that was comparable in LLCPK1 and MDCK. Non-tubular cell lines like fibroblasts and endothelial cells were significantly more vulnerable to oxalate. These observations were reflected by significant impairment to cell proliferation. We could not demonstrate an induction of apoptosis in any cell line. Part 2: both cell lines were more vulnerable to oxalate on the basolateral side. This effect was more pronounced in MDCK cells at high oxalate concentrations (4 mM). Cells are apparently more resistant on the apical (tubular) side. Our results show that sodium oxalate has a negative effect on the growth and survival of renal epithelial cells and, to a greater extent, also fibroblasts and endothelial cells. W

Topics: Animals; Apoptosis; Cell Survival; Cells, Cultured; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Kidney Calculi; Kidney Tubules; LLC-PK1 Cells; Oxalates; Probability; Sensitivity and Specificity; Statistics, Nonparametric; Swine; Urothelium

Renal tubular epithelium is the major target for oxalate induced injury, and sustained hyperoxaluria together with CaOx crystal formation/deposition may induce renal tubular cell damage and/or dysfunction. This may express itself in cell apoptosis. To evaluate the possible protective effects of certain agents (vitamin E, potassium citrate, allopurinol, verapamil and MgOH) on the presence and the severity of apoptotic changes caused by hyperoxaluria on renal tubular epithelium, an experimental study in rabbits was performed. Seventy rabbits were divided into seven different groups (each group n = 10): in group I severe hyperoxaluria was induced by continuous ethylene glycol (0.75%) administration started on day 0 and completed on day 14. Histologic alterations including crystal formation together with apoptotic changes (by using the TUNEL method) were evaluated on days 21 and 42, respectively. In the remaining experimental groups (groups II-VI), animals received some agents in addition to the induction of hyperoxaluria in an attempt to limit apoptotic changes. Group VII) animals constituted the controls. Kidneys were examined histopathologically under light microscopy for the presence and degree of crystal deposition in the tubular lumen. The percentage of apoptotic nuclei in the control group was significantly different from the other group animals (2.9-2.4%) in all study phases (P < 0.05). Apart from potassium citrate and allopurinol, the other medications seemed to prevent or limit the formation of apoptotic changes in renal tubular epithelium during the early period (day 21). The percentage of positively stained nuclei in animals undergoing potassium citrate medication ranged from 24.3% to 28.6%, with an average of 27.1%. This was 18.4% in animals receiving allopurinol. On the other hand, animals receiving magnesium hydroxide (MgOH), verapamil and vitamin E demonstrated limited apoptotic changes (11.2, 9.7, 8.7%, respectively) during this phase(P < 0.05). In the long-term (day 42), the animals receiving allopurinol and vitamin E showed a decrease in the percentage of the positively stained nuclei (13.5% and 8.3%, respectively). Animals in the other groups showed an increase in the number and percentage of apoptotic cells. Although, there was a significant decrease in the mean values of apoptosis in animals receiving vitamin E (8.7%-8.3%) and allopurinol (18.4%-13.5%) (P < 0.05), animals on verapamil, MgOH and potassium citrate medication had an increas

Topics: Allopurinol; Animals; Apoptosis; Cells, Cultured; Disease Models, Animal; Hyperoxaluria; In Situ Nick-End Labeling; Kidney Tubules; Male; Oxalates; Potassium Citrate; Rabbits; Random Allocation; Reference Values; Sensitivity and Specificity; Urinary Calculi; Urothelium; Verapamil; Vitamin E

Previous enzymatic determinations have suggested that serum oxalate concentrations in normal rats, the main animal model used in urolithiasis research, to be 3 to 5 times greater than those in healthy human subjects. In this report we validated this observation using a different method (ion chromatography) on serum samples from healthy rats and human subjects that were prepared and handled similarly. Oxalate recoveries during sample preparation for ion chromatography were strongly and variably affected by ultrafiltration devices employed for sample deproteinization and after Cl(-) removal by means of ion exchange. When oxalate recoveries were accounted for, we found significant differences in serum oxalate (6 human samples, 1.47 +/- 0.15 micromol/L; and 15 rat samples, 9.88 +/- 0.91 micromol/L). We conclude that ion-chromatographic techniques confirm the differences in serum oxalate concentrations between rats and human beings measured enzymatically and that failure to account for oxalate losses during sample preparation for ion chromatography can lead to significant underestimation of serum oxalate in both species.

Topics: Animals; Chromatography, Ion Exchange; Disease Models, Animal; Female; Humans; Male; Oxalates; Rats; Rats, Sprague-Dawley; Species Specificity

Oxalate induced renal calculi formation and the associated renal injury is thought to be caused by free radical mediated mechanisms. An in vivo model was used to investigate the effect of phycocyanin (from Spirulina platensis), a known antioxidant, against calcium oxalate urolithiasis. Male Wistar rats were divided into four groups. Hyperoxaluria was induced in two of these groups by intraperitoneal infusion of sodium oxalate (70 mg/kg) and a pretreatment of phycocyanin (100 mg/kg) as a single oral dosage was given, 1h prior to sodium oxalate infusion. An untreated control and drug control (phycocyanin alone) were also included in the study. We observed that phycocyanin significantly controlled the early biochemical changes in calcium oxalate stone formation. The antiurolithic nature of the drug was evaluated by the assessment of urinary risk factors and light microscopic observation of urinary crystals. Renal tubular damage as divulged by urinary marker enzymes (alkaline phosphatase, acid phosphatase and gamma-glutamyl transferase) and histopathological observations such as decreased tubulointerstitial, tubular dilatation and mononuclear inflammatory cells, indicated that renal damage was minimised in drug-pretreated group. Oxalate levels (P < 0.001) and lipid peroxidation (P < 0.001) in kidney tissue were significantly controlled by drug pretreatment, suggesting the ability of phycocyanin to quench the free radicals, thereby preventing the lipid peroxidation mediated tissue damage and oxalate entry. This accounts for the prevention of CaOx stones. Thus, the present analysis revealed the antioxidant and antiurolithic potential of phycocyanin thereby projecting it as a promising therapeutic agent against renal cell injury associated kidney stone formation.

Topics: Acid Phosphatase; Alkaline Phosphatase; Animals; Antioxidants; Bacterial Proteins; Biomarkers; Cyanobacteria; Disease Models, Animal; gamma-Glutamyltransferase; Hyperoxaluria; Kidney; Kidney Calculi; Lipid Peroxidation; Male; Oxalates; Phycocyanin; Rats; Rats, Wistar; Spirulina

Previous studies have described the inhibitory effects of citrate on calcium oxalate crystallization in place of crystal growth, but the effects of citrate on matrix proteins of stones has not been studied in vivo. To examine the effect of citrate on the matrix, we investigated the effect of citrate on osteopontin (OPN) expression, which we had previously identified as an important stone matrix protein. Control rats were treated with saline while rats of the stone group were treated with ethylene glycol (EG) and vitamin D3, and the citrate groups (low-dose and high-dose groups) were treated with a citrate reagent compound of sodium citrate and potassium citrate, in addition to EG and vitamin D3. The rate of renal stone formation was lower in the citrate groups than in the stone group. This was associated with a low expression of OPN mRNA in citrate-treated rats relative to that in the stone group. Citrate was effective in preventing calcium oxalate stone formation and reduced OPN expression in rats. Our results suggest that citrate prevents renal stone formation by acting against not only the crystal aggregation and growth of calcium oxalate but also OPN expression.

Topics: Animals; Blotting, Northern; Chelating Agents; Cholecalciferol; Citric Acid; Disease Models, Animal; Ethylene Glycol; Gene Expression; Immunohistochemistry; In Situ Hybridization; Male; Osteopontin; Oxalates; Rats; Rats, Wistar; RNA, Messenger; Sialoglycoproteins; Urinary Calculi

The effects of female sex hormones on urinary stone formation are not known. This study was conducted to investigate the effects of these hormones on stone formation by using an ethylene glycol (EG) and vitamin D-induced rat urolithiasis model.. Adult female Wistar rats were fed the same diet for four weeks and were then divided into four groups (N = 10 each). One group was administered 0.5 ml of olive oil three times per week for four weeks as a control. The other three groups were administered 0. 5 microg of vitamin D3 and 0.5 ml of 5% EG three times per week for four weeks. The rats in two of these three groups were oophorectomized, and the rats of the remaining group underwent a sham operation on the day before the start of the four-week treatment period. One of the two oophorectomized groups was then administered a supplementation of female sex hormones (0.1 mg of estrogen and 2.5 mg of progesterone 3 times per week for 4 weeks). On the first day of the fifth week of the experimental period, the degree of crystal deposition was determined histologically, and the calcium content in renal tissue was measured. We also investigated the level of osteopontin (OPN) mRNA in renal tissues by Northern blot analysis. OPN is a matrix protein thought to be a promoter of stone formation.. The urinary oxalate excretion, crystal deposition and calcium content in renal tissue and the expression of OPN-mRNA were greater in the oophorectomized rats compared with the controls, and the same parameters were inhibited by the female sex hormone supplementation.. These results suggest that female sex hormones can inhibit renal crystal deposition in EG-treated rats by suppressing the urinary oxalate excretion and the expression of OPN.

Topics: Animals; Blotting, Northern; Calcium; Citric Acid; Crystallization; Disease Models, Animal; Estradiol; Ethylene Glycol; Female; Kidney Calculi; Kidney Medulla; Kidney Tubules, Distal; Magnesium; Osteopontin; Ovariectomy; Oxalates; Phosphoproteins; Rats; Rats, Wistar; RNA, Messenger; Sialoglycoproteins; Vitamin D

To detect the role of the enzyme gamma-glutamyl carboxylase in an experimental stone-forming condition.. Urolithiasis was induced in experimental rats by (i) oral feeding of 1% ethylene glycol (EG) and (ii) feeding a calculus-producing diet containing 3% sodium glycolate.. A significant enhancement in the activity of renal vitamin-K-dependent gamma-glutamyl carboxylase was observed in both groups of experimental urolithic rats. Dicoumarol as well as EG treatment enhanced the accumulation of the endogenous substrate for the enzyme. The carboxylase activity was stimulated by sodium oxalate as well as calcium oxalate in vitro. A positive correlation was observed between lipid peroxidation and the renal gamma-glutamyl carboxylase activity.. The enhanced carboxylase activity observed in the hyperoxaluric condition is suggested to be due to stimulation of the enzyme by oxalate/calcium oxalate, increased concentration of endogenous carboxylase substrate and lipid peroxidation.

Topics: Animals; Carbon-Carbon Ligases; Dicumarol; Disease Models, Animal; Enzyme Activation; Ethylene Glycol; Glycolates; In Vitro Techniques; Kidney; Male; Oxalates; Rats; Rats, Wistar; Urinary Calculi

To determine the efficacy of (L)-cysteine and (L)-2-oxothiazolidine-4-carboxylic acid (OTZ) in reducing urinary oxalate excretion under hyperoxaluric conditions and to determine whether by inclusion of glycolate in a standard diet, cysteine:glyoxylate adduct can be detected in hyperoxaluric rats given either compound.. Hyperoxaluria (200% above basal) was induced 2 days prior to commencement of the studies and maintained throughout. After a 3 days baseline, animals were randomly allocated to a control or treatment group. Standard diet containing either (L)-cysteine or OTZ was then fed to the treatment groups for 5 days while standard diet alone was fed to the control groups. Urinary oxalate excretion was subsequently monitored and average daily rates were then compared with basal values. Plasma and urine were analyzed for adduct.. Both (L)-cysteine and OTZ significantly reduced urinary oxalate excretion relative to the basal hyperoxaluric level (28.6 +/- 1.5 micromol./day). While (L)-cysteine reduced oxalate excretion over the 5 day treatment period by only 7.82 +/- 1.39 micromol./day (27%), OTZ reduced it by 12.34 +/- 1.58 micromol./day (43%). Adduct could not be detected in plasma or urine in this study.. This study confirms that both (L)-cysteine and OTZ are effective in reducing urinary oxalate excretion under hyperoxaluric conditions, with OTZ being more effective than (L)-cysteine. These compounds were shown to be 3- to 4-fold more effective in reducing urinary oxalate excretion under hyperoxaluric conditions when compared with the results from previous studies under normooxaluric conditions.

Topics: Animals; Cysteine; Disease Models, Animal; Male; Oxalates; Pyrrolidonecarboxylic Acid; Rats; Rats, Inbred Strains; Thiazoles; Thiazolidines; Urinary Calculi

To evaluate the possible traumatizing effect of high-energy shockwaves (HESW) on new stone formation as indicated by crystal deposition in the renal parenchyma, we performed an experimental study in 50 rabbits. During severe oxaluria induced by continuous ethylene glycol (0.75%) administration, animals in the first group (N = 15) received 500 to 1500 shockwaves. Animals in the second group (N = 15) underwent no specific therapy apart from ethylene glycol administration. In a third group of animals (N = 15), only shockwave administration was applied. Sham group animals constituted the last group in our study (N = 5). Three months after shockwave application, tissue sections obtained from treated and untreated kidneys were evaluated histopathologically under light and transmission electron microscopy (TEM) for the presence and degree of crystal deposition in the cortical parenchymal region subjected to HESW. Crystal deposition was evident in the intercellular region and intratubular parts of the parenchyma in animals subjected to HESW application, especially in those receiving relatively high (1000 or 1500) numbers of shockwaves. On the other hand, no crystal formation and deposition was detectable in animals undergoing only ethylene glycol therapy or shockwave administration alone. Sham group animals demonstrated no significant renal histopathology. The traumatic effects of HESW should be evaluated as a factor in new stone formation after SWL.

Topics: Animals; Crystallization; Disease Models, Animal; Ethylene Glycol; Ethylene Glycols; High-Energy Shock Waves; Kidney; Kidney Calculi; Microscopy, Electron; Oxalates; Prospective Studies; Rabbits; Recurrence

Forty adult male Wistar rats were placed in metabolic cages on a Ca-deficient diet (0.1%) for 7 days and then on a Ca-deficient, Na-oxalate (NaOx) enriched diet (20 mg/100 g) for another 14 days. The animals were subdivided into three groups receiving three different types of mineral water: group I (n = 13), Badoit (Ca 222 mg/l); group II (n = 14), Contrexéville (Ca 467 mg/l); and group III (n = 13), Evian (Ca 78 mg/l). Another series of 25 rats (group I, n = 9; group II, n = 8; group III, n = 8) underwent the same study protocol, except that they received a normal Ca diet (1%). On the low-Ca diet, urinary Ca-Ox monohydrate (COM) crystals were observed only under the Na-Ox diet, with a mean crystal number significantly greater in group III (16.7 +/- 4.5 crystals/mm3) than in group I or II rats (2.5 +/- 1.5 or 4.1 +/- 1.5 crystals/mm3, respectively). Urinary Ca concentrations decreased in all groups (P < 0.001) under the Na-Ox diet, while urinary oxalate concentrations increased in all groups (P < 0.001). On the normal Ca diet, COM crystal excretion was observed only with the Na-Ox-enriched diet, but in this case feeding the Na-Ox diet did not modify urinary oxalate excretion. Ca/Ox ratio was significantly lower under 0.1% Ca diet than under normal Ca diet, related with the type and the number of crystals observed, demonstrating that assessment of crystalluria can provide an index of disease severity. Moreover, the hardness of the drinking water influences urinary COM crystal excretion only under a low-Ca, oxalate-rich diet, suggesting that the total calcium intake rather than the water calcium content is an important factor in the occurrence of Ca-Ox nephrolithiasis.

Topics: Animals; Calcium; Calcium Oxalate; Calcium, Dietary; Crystallization; Diet; Disease Models, Animal; Magnesium; Male; Oxalates; Rats; Rats, Wistar; Urinary Calculi

Vitamin B-6 deficiency has been reported to produce behavioral, neurophysiological and neuropathological abnormalities in a variety of species. In this investigation we used brainstem auditory evoked potentials (BAEP) to determine if vitamin B-6 deficiency in cats affected peripheral and brainstem auditory pathways. Brainstem auditory evoked potentials were recorded from growing cats as they developed vitamin B-6 deficiency, which was confirmed using clinical, hematological and urinary criteria. The BAEP interwave intervals measured from early (wave 1 or 1N) to late waves (5N) or from middle (wave 3) to late waves increased significantly, whereas interwave intervals from early to middle waves did not differ significantly. These results indicate that vitamin B-6 deficiency affects one or more structures of the brainstem that generate the later parts of the BAEP. The finding of prolonged interwave intervals in vitamin B-6-deficient animals is consistent with slowed axonal conduction velocity secondary to defective myelination. Recording BAEP provided a noninvasive means of detecting effects of vitamin B-6 deficiency on specific parts of the central nervous system.

Topics: Acoustic Stimulation; Animals; Body Weight; Cats; Disease Models, Animal; Electrodes; Electrophysiology; Evoked Potentials, Auditory, Brain Stem; Hemoglobins; Oxalates; Pyridoxine; Vitamin B 6 Deficiency

Sodium oxalate injected into young rats, via the intraperitoneal route, at a dose of 8 mg per 100 g of body weight, induced death in 50 p. cent of animals, and induced calcium oxalate crystals in renal tissue. When a zinc solution was administered prior to sodium oxalate, at the dose of 12 micrograms/100 g of body weight, the mortality rate decreased, and at the same time oxalate and calcium deposits were significant reduced (respectively P less than 0.01; P less than 0.01). The same results were found when zinc was administered at 24 micrograms/100 g of body weight, however, oxalic accumulation was found to be significantly lower in this group than in the group treated at 12 micrograms. This protection against calcium oxalate deposits was complete in the animals treated with various doses of zinc, because compared to reference animals, which received distilled water, calcium accumulation in these groups was not different and oxalate accumulation was also found to be lower (respectively P less than 0.05; P less than 0.001). Microscopic examination showed calcium crystals only in the group treated with sodium oxalate, localized preferentially in the renal papilla. All these experiments conclude on the total inhibitory effect of zinc on experimental lithiasis induced by oxalic acid, even though it was administered at a dose of only 12 micrograms/100 g of body weight.

Topics: Animals; Calcium; Disease Models, Animal; Drug Evaluation, Preclinical; Kidney Calculi; Male; Oxalates; Rats; Rats, Inbred Strains; Sulfates; Zinc; Zinc Sulfate

To better understand the pathogenesis of nephrolithiasis, we developed a new animal model that closely mimics human calcium oxalate stone disease. Rats were treated with a regimen that combines moderate hyperoxaluria (produced by 10 days of feeding with 3% ammonium oxalate) with mild proximal tubular injury/dysfunction (produced by 8 daily injections of gentamicin sulfate -40 mg./kg.). This combined treatment caused a marked increase in the incidence of calcium oxalate crystals and stones over that seen in animals treated with oxalate or gentamicin alone. Using a semiquantitative scoring system for estimating the abundance of crystals in coronal sections of kidneys, we found that 63% of animals receiving gentamicin plus oxalate showed "moderate" numbers of crystal, as compared to 8% of animals receiving oxalate alone; and the majority of the crystals occurred in the papilla, a pattern similar to that seen in human stone disease. Untreated rats and rats treated with gentamicin alone did not exhibit calcium oxalate crystals or stones. Despite the abundance of crystals and stones, animals receiving gentamicin plus oxalate retained relatively normal renal function as judged by creatinine clearance. Thus, the model has several advantages over preexisting models of nephrolithiasis. Crystal and stone deposition develop rapidly (within 14 days). The pattern of deposition resembles that seen in human stone disease and renal function remains relatively normal. These findings indicate that this model of nephrolithiasis may prove useful for studies of the pathogenesis of stone disease. Moreover, they suggest that renal tubular injury and/or dysfunction may produce conditions conducive to the formation and growth of calcium oxalate stones.

Topics: Animals; Calcium Oxalate; Disease Models, Animal; Gentamicins; Kidney; Kidney Calculi; Kidney Tubules; Male; Microscopy, Electron; Microscopy, Electron, Scanning; Oxalates; Rats; Rats, Inbred Strains

The low incidence of atherosclerosis and other degenerative diseases including stone disease in the Greenland Eskimo has been attributed to their high consumption of oily fish with its high concentration of eicosapentaenoic acid (EPA). Man cannot synthesis EPA from the precursor essential fatty acid, linolenic acid, and can only assimilate preformed EPA present in fish and fish oil, to bring about a change in the pathway of eicosanoid metabolism from the n-6 to the n-3 series. With a westernised diet the oxygenated products of renal prostaglandin synthesis are metabolites of the n-6 series and these are known to play an important role in several pathophysiological states including stone disease. Our previous studies have shown a relationship between prostaglandin activity and urinary calcium excretion and it would seem that the initiating factor/s for stone formation trigger the mechanisms for prostaglandin synthesis resulting in the biochemical abnormalities associated with stone disease. The Eskimo may be protected from these events by possession of an eicosanoid metabolism that follows an n-3 pathway. To test this hypothesis experiments were performed using an animal model of nephrocalcinosis. The animals were divided into three groups; one group was given an intra-peritoneal injection of 10% calcium gluconate daily for 10 days to induce nephrocalcinosis; a second group was fed MaxEPA fish oil before and during the calcium gluconate injections and a third group only received an intra-peritoneal injection of N saline. A group of 12 recurrent, hypercalciuric/hyperoxaluric stone-formers were treated with fish oil for eight weeks to study the effects on solute excretion. Nephrocalcinosis, which was readily produced in the control animals, was prevented in the experimental animals by pre-treatment with fish oil and urine calcium excretion was significantly reduced. The urinary calcium and oxalate excretion in the recurrent, hypercalciuric stone-formers was significantly reduced with fish oil treatment over an eight week period. There were no untoward side-effects. These studies indicate that the incorporation of EPA in the diet as a substitute metabolic pathway could be a unique way of correcting the biochemical abnormalities of idiopathic urolithiasis.

Topics: Adult; Aged; Animals; Calcium; Disease Models, Animal; Drug Evaluation; Drug Evaluation, Preclinical; Eicosapentaenoic Acid; Female; Humans; Kidney; Kidney Calculi; Male; Microradiography; Middle Aged; Nephrocalcinosis; Oxalates; Oxalic Acid; Rats; Rats, Inbred Strains; Recurrence; Spectrophotometry, Atomic

Topics: Acute Kidney Injury; Animals; Cat Diseases; Cats; Disease Models, Animal; Female; Glyceric Acids; Hyperoxaluria; Male; Oxalates; Oxalic Acid

This paper examines the kinetics of calcium deposition in rat kidneys after an intraperitoneal sodium oxalate injection. From the results we conclude that only a limited portion of tubular surface is available for adsorption of calcium oxalate crystals, that adsorpption of calcium oxalate crystals onto tubular epithelium is a process of greater than first order with regard to the dose, and that the washout of retained particles from the tubules is a first-order process as related to time. Also, we conclude that in these animals, which were subjected to a large oxalate challenge, the deposition of calcium oxalate crystals is virtually all intratubular.

Topics: Animals; Calcium; Disease Models, Animal; Dose-Response Relationship, Drug; Kidney; Kidney Calculi; Male; Oxalates; Rats; Sodium

A single intraperitoneal injection of sodium oxalate was used to induce intrarenal tubular precipitation of calcium oxalate in rats. This experimental model was used to screen the efficacy of hydrochlorothiazide, orthophosphate, methylene blue, trypan blue, retinal folic acid, neuraminidase, and lysozyme in retarding intratubular calcium oxalate precipitation. Orthophosphate caused a 53 per cent reduction in calcium oxalate precipitation relative to the control animals.

Topics: Animals; Calcium; Disease Models, Animal; Drug Evaluation, Preclinical; Female; Folic Acid; Hydrochlorothiazide; Methylene Blue; Muramidase; Neuraminidase; Oxalates; Phosphates; Rats; Trypan Blue; Urinary Calculi; Vitamin A

A model was designed to study the relation between urinary infection and vesicoureteral, low-grade, total reflux. Surgical alteration of the ureterovesical junction produced grade 2 vesicoureteral reflux in seven of 13 animals. In the other six animals, surgery had rendered the vesicoureteral junction marginally competent and chronic bladder infection caused grade 2 reflux. It was found that grade 2 vesicoureteral reflux in the adult monkey neither prolongs urinary tract infection nor causes continued renal infection.

Topics: Animals; Disease Models, Animal; Escherichia coli Infections; Female; Foreign Bodies; Haplorhini; Macaca; Oxalates; Proteus Infections; Proteus mirabilis; Pyelonephritis; Urinary Bladder; Vesico-Ureteral Reflux

The growth-inhibiting influence of hydroxy-anthraquinone derivatives of root of rubia in various calcium offerings was investigated using a foreign-body bladder calculus model in rabbits. Following oral doses of glycoside-bound and free aglycemics a pronounced calcium-complex binding effect and a significant reduction in the growth rate of the calculi was observed. Use of anthraquinone glycosides to prevent recurrence of calcium-containing urinary stones is recommended.

Topics: Animals; Anthraquinones; Calcium; Disease Models, Animal; Female; Glycosides; Oxalates; Phosphates; Rabbits; Structure-Activity Relationship; Urinary Bladder Calculi

Utilizing a low pyridoxine, ethylene glycol-fed rat model, various modes of anticalculus therapy were compared. Prophylactic papillary and parenchymal oxalate stone therapy is most effective with magnesium oxide. Hydrochlorothiazide is next in order as the therapy of choice in this group. A high calcium diet seems to negate the effect of magnesium oxide. Methylene blue, magnesium oxide, and even sodium phosphate, are not as effective as hydrochlorothiazide in the combined prevention and treatment of preformed parencymal calcium oxalate stones. No agent seems to have a profound effect on preformed apical papillary calculi.

Topics: Animals; Disease Models, Animal; Hydrochlorothiazide; Kidney Calculi; Magnesium Oxide; Male; Methylene Blue; Oxalates; Phosphates; Rats

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Black People; Child; Disease Models, Animal; Guinea Pigs; Hemosiderosis; Humans; Iron; Leukocytes; Liver; Oxalates; South Africa; Thalassemia

The clinical picture resembling fundus albipunctatus was seen to develop in rabbits following subcutaneous injection with dibutyl oxalate. On histologic examination, the flecks were found to be due to intracellular accumulation of calcium oxalate in the RPE cells. The clinical and histologic features of this animal model closely resemble the recently described entity of oxalate retinopathy in humans which was seen in the presence of high circulating oxalate levels. It is suggested that the presence of metabolic disorders or toxicity which are known to cause oxalate depositions should be sought in patients with fundus albipunctatus.

Topics: Animals; Calcium; Crystallization; Disease Models, Animal; Epithelium; Injections, Subcutaneous; Kidney Tubules; Lens, Crystalline; Male; Oxalates; Rabbits; Retina; Retinal Degeneration

Topics: Animal Feed; Animals; Calcium; Calculi; Disease Models, Animal; Ethylene Glycols; Female; Foreign Bodies; Kidney; Magnesium; Oxalates; Rabbits; Urinary Bladder Calculi

Topics: Administration, Oral; Animals; Citrates; Citric Acid Cycle; Disease Models, Animal; Ethylene Glycols; Glyoxylates; Hydroxyproline; Injections, Intraperitoneal; Kidney Calculi; Malates; Oxalates; Oxaloacetates; Rats; Succinates

Topics: Aging; Animals; Biological Transport, Active; Calcium; Cricetinae; Disease Models, Animal; Female; Heart; Heart Failure; Male; Myocardium; Organ Size; Oxalates; Sarcoplasmic Reticulum