Urinary Oxalate Levels Research Articles

Impact of Phyllantus niruri and Lactobacillus amylovorus SGL 14 in a mouse model of dietary hyperoxaluria.

Hyperoxaluria is a pathological condition which affects long-term health of kidneys. The present study evaluates the impact of the combination of Lactobacillus amylovorus SGL 14 and the plant extract Phyllantus niruri (namely Phyllantin 14™) on dietary hyperoxaluria. Safety and efficacy of Phyllantin 14 have been evaluated in vivo. Mice C57BL6 fed a high-oxalate diet were compared to mice fed the same diet administered with Phyllantin 14 by gavage for 6 weeks. Control mice were fed a standard diet without oxalate. No adverse effects were associated to Phyllantin 14 supplementation, supporting its safety. Mice fed a high-oxalate diet developed significant hyperoxaluria and those administered with Phyllantin 14 showed a reduced level of urinary oxalate and a lower oxalate-to-creatinine ratio. Soluble and insoluble caecal oxalate were significantly lower in treated group, a finding in agreement with the colonisation study, i.e. mice were colonised with SGL 14 after 3 weeks. Microbiota analysis demonstrated that both oxalate diet and Phyllantin 14 can differently modulate the microbiota. In conclusion, our findings suggest that Phyllantin 14 supplementation represents a potential supportive approach for reducing urinary oxalate and/or for enhancing the efficacy of existing treatments.

Human kidney stone matrix proteins alleviate hyperoxaluria induced renal stress by targeting cell-crystal interactions

Increased levels of urinary oxalate also known as hyperoxaluria, increase the likelihood of kidney stone formation through enhanced calcium oxalate (CaOx) crystallization. The management of lithiatic renal pathology requires investigations at the initial macromolecular stages. Hence, the current study was designed to unravel the protein make-up of human kidney stones and its impact on renal cells' altered proteome, induced as the consequence of CaOx injury. CaOx kidney stones were collected from patients; stones were pooled for entire cohort, followed by protein extraction. Immunocytochemistry, RT-PCR and flow-cytometric analysis revealed the promising antilithiatic activity of kidney stone matrix proteins. The iTRAQ analysis of renal cells showed up-regulation of 12 proteins and down-regulation of 41 proteins due to CaOx insult, however, this differential expression was normalized in the presence of kidney stone matrix proteins. Protein network analysis revealed involvement of up-regulated proteins in apoptosis, calcium-binding, inflammatory and stress response pathways. Moreover, seven novel antilithiatic proteins were identified from human kidney stones' matrix: Tenascin-X-isoform2, CCDC-144A, LIM domain kinase-1, Serine/Arginine receptor matrix protein-2, mitochondrial peptide methionine sulfoxide reductase, volume-regulated anion channel subunit-LRRC8A and BMPR2. In silico analysis concluded that these proteins exert antilithiatic potential through crystal binding, thereby inhibiting the crystal-cell interaction, a pre-requisite to initiate inflammatory response. Thus, the outcomes of this study provide insights into the molecular events of CaOx induced renal toxicity and subsequent progression into nephrolithiasis.

Correlation of Dietary Factors and Physical Activities With the Formation of Renal Stones

Objective: This study was undertaken to find out the roles of dietary factors and physical activities in the formation of renal stones in our socio-demographic conditions. Methods: This cross-sectional analytical study was conducted among 70 patients from October 2011 to November 2012 in the department of SSMCMH and a few other private hospitals in Dhaka city. The study included all patients of either gender and all ages attending our out-patient department who were diagnosed to have renal stones. The dietary habits of the patients were explored by face to face interview using food frequency questionnaire (FFQ). The physical activities were evaluated by structured questionnaire, and the metabolic work-ups were done by urinalysis and blood analysis. The results were reviewed and analyzed with the help of SPSS 17. Result: Out of 70 patients about one-third were female (31.4%) and two-third were male (68.6%). Most of the study people belonged to age group 40-50 years. Mean was 43.7 years with standard deviation of 10.28 years. One-fifth of the respondents did minimal activities (0-5 hrs/day), One –third moderate activities (5-10 hrs/day) and about half severe activities (10-15hrs/day). One-fifth did not take any table salt but about one-fourth indulged much (>half tsf/day) and more than half took excessive (> 1tsf/day) salt. About 57.1% stone patients of the present study habitually have taken excessive salt, 24.3% patients took much salt and 18.6% used no added table salt. About one-third (37.71%) of the patients took calcium, one-fourth (25.71%) vitamin-D, one-fifth ascorbic acid and the rest had no supplementations. The patients having supplementations found to have more urinary levels of the corresponding supplements. More ingestion of green leafy vegetables and fruits and juices are associated with increased level of urinary oxalate. 24-hrs urinary oxalate level found to be associated with increased occurrence of renal stones. Most of the patients (64.3%) ingested habitually inadequate amount of fluid. Conclusion: The study showed some important observational facts in regard to the respondent’s diet and physical activities. The dietary and lifestyle modifications can reduce urinary stone disease. Bangladesh Journal of Urology, Vol. 18, No. 1, Jan 2015 p.23-27

Comparative Study of Urinary Minerals and Their Effect on Stone Formation in Two Groups of Cystic Fibrosis (CF) and Healthy Children

Background: Cystic Fibrosis (CF) is a systemic autosomal disorder and the most important chronic lung disease in children. Oxalate is the end product of vitamin C metabolism, which increases the risk of kidney stones, urinary bladder stones, and calcium deposits in CF patients. Objectives: Considering the increased mineral excretion and the rate of stone formation in the urinary tract, examining the excretion of minerals will greatly help resolve clinical problems. Methods: This descriptive-analytical study was performed on CF and healthy children in Gorgan in 2018 - 19. In this study, 40 CF children and 40 healthy children were randomly selected. After obtaining informed consent from the parents of the children, a random urine sample was collected to evaluate urine minerals. Children with abnormal urinary mineral excretion underwent ultrasonography. The data were analyzed by SPSS 18 using descriptive indices (mean ± SD, frequency, and percentage) and statistical tests (independent t-test, chi-square test, and nonparametric tests). Results: Out of 80 CF and healthy children, 34 were girls, and the rest was boys. The mean age of the patients was 4.34 ± 3.38. The age difference was not significant between the groups (P > 0.05). The mean urinary levels of phosphorus, uric acid, magnesium, and citrate were 0.87 ± 1.01, 1.16 ± 0.68, 0.23 ± 0.18, 2.37 ± 3.13 mg/mg of creatinine. In the pediatric patient group, respectively (P < 0.001). The mean urinary calcium level in CF patients was 0.28 ± 0.39, which was lower than that in the healthy group. The mean urinary oxalate level was 0.13 ± 0.20 in CF patients, which was higher than that in the healthy group (P > 0.05). Hyperoxaluria, hyperuricosuria, hypomagnesiuria, and hypocitraturia occurred in 35, 30, 62, and 7.5% of the CF patients, respectively. Among the urinary minerals studied, hyperoxaluria was found to be a major determinant of stone formation risk in CF. No correlation was observed between the formation of stones and the rate of excretion of minerals (P > 0.05). Conclusions: In summary, CF patients are at an increased risk of developing citrate and calcium stones compared to the healthy group, which is associated with hyperuricosuria, hypocitraturia, and hyperoxaluria.

The relationship between gut microbiota and short chain fatty acids in the renal calcium oxalate stones disease.

The relationship of gut microbiota and calcium oxalate stone has been limited investigated, especially with no study of gut microbiota and short chain fatty acids (SCFAs) in nephrolithiasis. We provided Sprague Dawley rats of renal calcium oxalate stones with antibiotics and examined the renal crystals deposition. We also performed a case-control study by analyzing 16S rRNA microbial profiling, shotgun metagenomics and SCFAs in 153 fecal samples from non-kidney stone (NS) controls, patients with occasional renal calcium oxalate stones (OS) and patients with recurrent stones (RS). Antibiotics reduced bacterial load in feces and could promote the formation of renal calcium crystals in model rats. In addition, both OS and RS patients exhibited higher fecal microbial diversity than NS controls. Several SCFAs-producing gut bacteria, as well as metabolic pathways associated with SCFAs production, were considerably lower in the gut microbiota among the kidney stone patients compared with the NS controls. Representation of genes involved in oxalate degradation showed no significance difference among groups. However, fecal acetic acid concentration was the highest in RS patients with high level of urinary oxalate, which was positively correlated with genes involvement in oxalate synthesis. Administration of SCFAs reduced renal crystals. These results shed new light on bacteria and SCFAs, which may promote the development of treatment strategy in nephrolithiasis.

P0064RENAL PHENOTYPES IN A GROUP OF PATIENTS WITH MITOCHONDRIAL DISEASES

Abstract Background and Aims Mitochondrial diseases (MDs) are one of the most common inherited metabolic disorders caused by mutations of either mitochondrial or nuclear genes involved in the oxidative phosphorylation pathway. Tissues with high energy demand (i.e. brain and skeletal muscle) are preferentially affected, and MDs are not rarely referred to as mitochondrial encephalomyopathies. However, one of the hallmarks of MDs is multisystemic involvement, with large clinical variability and severity due to different mitochondrial DNA heteroplasmy levels. Given the possibility of multisystemic phenotype of MDs, renal involvement has been suggested, based on renal cells vulnerability to poor energy supply. A specific mitochondrial kidney disease is thought to underlie renal manifestations, therefore theoretically every district of the nephron might be affected by MDs. Regarding tubular involvement, we suggested a possible association between nephrolithiasis and MDs, based on data of 3 related stone formers with reduced urinary citrate excretion and MELAS syndrome. The aim of this study is to provide a clinical description of the renal phenotypes of patients with MDs. Method In 2019, 6 patients with MDs routinely followed by the Neurology outpatient clinic of our Institution were randomly asked to perform renal screening. Genetic tests, blood and 24-hour urine analyses were assessed in the whole population. The main comorbidities were recorded. Glomerular filtration rate (GFR) was estimated using creatinine clearance. Results Half of the patients were female, the average age at renal evaluation was 48±15 years; diabetes, hypertension and neurosensorial hypoacusia occurred in 4, 1 and 2 subjects, respectively. Five patients had m.3243A>G mutation, responsible for more than 85% of maternal inherited diabetes and deafness (MIDD) and syndrome of mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS). The remaining patient carried the m.8363G>A variant, reported to be associated with a multisystem MDs known as Leigh syndrome (subacute necrotizing encephalomyelopathy). Median serum creatinine was 0.6 mg/dL (IQR: 0.5-1.1) with median GFR of 92 mL/min/1.73 m2 (IQR: 40-117). Three patients exhibited signs of kidney disease: one had both reduced GFR and proteinuria (eGFR 37 mL/min/1.73 m2 and 750 mg/day respectively), one had renal impairment (58 mL/min/1.7 3m2) and severe hypocitraturia (22 mg/day), one showed increased urinary calcium excretion (348 mg/day). In one patient, evaluation of the type of proteinuria has not been performed yet. Serum lactate was 3.1±1.9 mmol/L, urinary pH 5.8±0.3 and median urinary citrate excretion 593 mg/24h (IQR: 310-923). No relevant results were found on serum and/or urinary levels of sodium, potassium, magnesium, phosphorus, urate, chloride, oxalate, parathyroid hormone and 25-OH vitamin D. Conclusion These results confirmed the presence of renal disease and its heterogeneity in patients with MDs. A complete renal screening is necessary in these subjects in order to early recognize renal involvement and carefully select candidates for further diagnostic work-up including renal biopsy. A consensus on the optimal renal screening for these patients has yet to be established.

LB002ILLUMINATE-A, A PHASE 3 STUDY OF LUMASIRAN, AN INVESTIGATIONAL RNAI THERAPEUTIC, IN CHILDREN AND ADULTS WITH PRIMARY HYPEROXALURIA TYPE 1 (PH1)

Abstract Background and Aims PH1 is a rare genetic disorder characterized by hepatic oxalate overproduction, leading to recurrent kidney stones, nephrocalcinosis, progressive kidney failure, and multiorgan damage from systemic oxalosis. There are no approved pharmacologic therapies for PH1. Lumasiran is a subcutaneously-administered investigational RNAi therapeutic that targets glycolate oxidase to reduce hepatic oxalate production. We report the first results from the six-month, double-blind period of ILLUMINATE-A, a randomized, placebo-controlled Phase 3 study to evaluate lumasiran in patients with PH1. Method Key inclusion criteria: age≥6 years, 24hr urinary oxalate (UOx)≥0.70 mmol/24hr/1.73m2, confirmed PH1 diagnosis, eGFR≥30 mL/min/1.73m2. Randomization: 2:1; lumasiran (n=26), placebo (n=13). Dosing: 3 mg/kg monthly×3, then quarterly. Primary endpoint: percent change in 24hr UOx excretion from baseline to month (M) 6. Primary comparison: least square (LS) mean treatment difference in percent change from baseline (average of M3-6). Results Lumasiran led to a statistically significant percent reduction in 24hr UOx excretion compared to placebo: the LS mean change from baseline to M6 (average of M3-6) was −65.4% with lumasiran and −11.8% with placebo (LS mean difference: −53.5%; p=1.7 × 10−14). Subgroup analyses of the primary endpoint showed a consistent effect of lumasiran across age, baseline UOx, eGFR, and concomitant pyridoxine use. Lumasiran led to statistically significant improvements in all hierarchically tested secondary endpoints, including: proportion of lumasiran-treated patients that achieved normalization or near-normalization of 24hr UOx at M6 (84% vs 0% of placebo-treated patients, p=8.3 × 10−7), and percent change in plasma oxalate from baseline to M6 (average of months 3-6) (-39.5%, p=2.9 × 10−8). There were no serious or severe adverse events. The most common adverse events related to lumasiran were mild, transient injection site reactions. Conclusion Lumasiran resulted in clinically meaningful, rapid, sustained, and statistically significant reductions in urinary and plasma oxalate levels compared to placebo during the six-month double-blind period. Lumasiran has a favorable safety profile.

CRISPR/Cas9–mediated metabolic pathway reprogramming in a novel humanized rat model ameliorates primary hyperoxaluria type 1

Primary hyperoxaluria type I is caused by mutations in the alanine glyoxylate aminotransferase gene (AGXT), leading to accumulation of glyoxylate and subsequent production of oxalate and urolithiasis. Here, we generated a novel rat model of primary hyperoxaluria type I that carries a D205N mutation in the partially humanized Agxt gene through the CRISPR/Cas9 system. The AgxtD205N mutant rats showed undetectable alanine glyoxylate aminotransferase protein expression, developed hyperoxaluria at 1 month of age and exhibited severe renal calcium oxalate deposition after ethylene glycol challenge. This suggests our novel model is more relevant to the human disease than existing animal models. To test whether this model could be used for the development of innovative therapeutics, SaCas9 targeting hydroxyacid oxidase 1, responsible for metabolizing glycolate into glyoxylate, was delivered via adeno-associated viral vectors into newborn rats with primary hyperoxaluria type 1. This approach generated nearly 30% indels in the Hao1 gene in the liver, leading to 42% lower urine oxalate levels in the treated group than in the control group and preventing the rats with primary hyperoxaluria type 1 from undergoing severe nephrocalcinosis for at least 12 months. Thus, our results demonstrate that this partially humanized AgxtD205N rat strain is a high-performing model of primary hyperoxaluria type 1 for understanding pathology, and the development of novel therapeutics, such as reprogramming of the metabolic pathway through genome editing.

Clinical validation of urinary indole-reacted calcium oxalate crystallization index (iCOCI) test for diagnosing calcium oxalate urolithiasis

An indole-reacted calcium oxalate crystallization index (iCOCI) test was developed to quantify the total competence of urine to precipitate calcium oxalate (CaOx) crystals. We conducted the prospective cohort study in accordance with the STARD guideline to evaluate the accuracy of urinary iCOCI test (index test) for diagnosing urolithiasis. A total of 281 participants were recruited for the study. Levels of urinary iCOCI were determined in the pre-diagnostic 24-h urine samples. Positive urinary iCOCI (≥ 0.6 COM eqv., g/L) was accounted for 51% (144/281), and the rest of 49% (137/281) were negative. Non-contrast CT imaging (reference standard) was subsequently performed for the definite diagnosis of urolithiasis to divide the participants into two groups, non-stone subjects (NSS, n = 122) and stone-forming subjects (SFS, n = 159). It should be noted that only subjects who currently had urinary stone at the time of study were classified as SFS. Urinary iCOCI levels in the SFS were significantly higher than the NSS. ROC analysis revealed an area under curve (AUC) of 0.893 (95% CI: 0.855–0.932) in separating NSS from all SFS. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, positive likelihood ratio (LH+) and negative likelihood ratio (LH−) of urinary iCOCI test for diagnosis of all urolithiasis were 87%, 80%, 84%, 84%, 83%, 4.44 and 0.16, respectively. Of 159 SFS, 38 were confirmed to have CaOx stones. Among these 38 CaOx SFS, only 2 had negative urinary iCOCI test. The AUC of urinary iCOCI test for separating CaOx SFS from NSS was markedly high (0.946, 95% CI: 0.914–0.978). Sensitivity, specificity, PPV, NPV, accuracy, LH+ and LH− of urinary iCOCI test for diagnosing CaOx urolithiasis were 95%, 86%, 68%, 98%, 88%, 6.80 and 0.06, respectively. Conclusion, we clinically validated that an innovative non-invasive urinary iCOCI test was highly accurate to diagnose urolithiasis, especially CaOx stone. With its high sensitivity and NPV, urinary iCOCI test is clinically intended to use as a screening test for CaOx urolithiasis. LH− of 0.06 indicates that negative result of urinary iCOCI test is highly accurate to rule out the CaOx stone formation. It is noted that urinary iCOCI level is expressed as arbitrary unit, and it is not directly related to the actual physiological level of urinary oxalate.

The Activity of Purple Sweet Potato Leaves (Ipomea batatas Ver.) Extract to Calcium Oxalate Concentration of Male Rat (Rattus novergicus)

Purple sweet potato leaves (Ipomea batatas Ver.) has been proven to have anti-lithiasis effects in vitro in treating kidney stone disease. This is due to the high content of potassium in the leaves. The study aimed to analyze the effect of purple sweet potato leaf extract on kidney stone decay in male white rats induced by ethylene glycol 0.75% and ammonium chloride 2% for 10 days. In this study, 24 mice were divided into 6 groups: normal or without induction group, positive control, negative control, dose group 300 mg/200-gram body weight, 400 mg/200-gram body weight, and 500 mg/200-gram body weight. The parameters observed were calcium levels in the urine tested using Atomic Absorption Spectrophotometry, oxalate levels in urine tested using UV VIS Spectrophotometer. The results of this study indicate that purple sweet potato leaf extract at a dose of 500 mg/200-gram body weight can increase the levels of calcium and oxalate in the urine of rats compared with negative controls.

PD04-06 SIGNIFICANT POST-PRANDIAL URINARY HYPEROXALURIA OBSERVED BY SPOT TESTING INDIVIDUAL URINARY VOIDS

You have accessJournal of UrologyStone Disease: Basic Research & Pathophysiology I (PD04)1 Apr 2020PD04-06 SIGNIFICANT POST-PRANDIAL URINARY HYPEROXALURIA OBSERVED BY SPOT TESTING INDIVIDUAL URINARY VOIDS William Donelan*, Pedro Espino-Grosso, Tina Esfandiary, Alexandria Voigt, Paul Dominguez-Gutierrez, Cuong Nguyen, and Benjamin Canales William Donelan*William Donelan* More articles by this author , Pedro Espino-GrossoPedro Espino-Grosso More articles by this author , Tina EsfandiaryTina Esfandiary More articles by this author , Alexandria VoigtAlexandria Voigt More articles by this author , Paul Dominguez-GutierrezPaul Dominguez-Gutierrez More articles by this author , Cuong NguyenCuong Nguyen More articles by this author , and Benjamin CanalesBenjamin Canales More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000824.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Urinary oxalate is a vital component of supersaturation profiles and a major driving force for crystallization. Although routinely assessed by metabolic testing, the 24-hour urine collection lacks the ability to measure spikes in urine oxalate concentration, particularly those that follow the consumption of a high oxalate-containing meal. To determine whether oxalate spikes are important for predicting stone risk, we measured oxalate concentration in each void over a 24-hour period in individuals who ingested a high oxalate-containing meal. METHODS: After IRB approval, healthy non-stone formers (6 F, 5 M) were prospectively enrolled to collect consecutively voided urine specimens over a 24-hour period. Participants were given a dietary log and instructed to consume food low in oxalate throughout the entire collection period. At noon on their collection day, participants were asked to consume a high-oxalate load (HOL) in the form of 100g spinach. Participants collected urinary voids in separate containers approximately every 3 hours during the day. Oxalate levels were evaluated on each specimen as well as the final combined 24-hour collection using the Trinity Biotech Oxalate Assay. RESULTS: The 24-hour average urinary oxalate concentrations measured approximately 0.45mM, which is at the normal high end for healthy individuals. We found that within the time period 2-8 hours post-HOL, 43.7% of the daily oxalate excretion occurred, and participants had hyperoxaluric voids that were significantly higher compared to baseline levels or the mean of the entire 24-hour period. CONCLUSIONS: The study demonstrates that significant post-prandial urinary hyperoxaluric spikes occur that are missed using the classical 24-hour urine test. This, together with hyperoxaluria as a potential etiopathological entity in a variety of disease processes, underscores the need for regular temporal-based monitoring of urinary oxalate levels. Source of Funding: This work was supported in part by the Urology Care Foundation Research Scholar Award Program and The Endourological Society; and by The National Institutes of Health Grant 5T32DK094789-05. © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e80-e80 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information William Donelan* More articles by this author Pedro Espino-Grosso More articles by this author Tina Esfandiary More articles by this author Alexandria Voigt More articles by this author Paul Dominguez-Gutierrez More articles by this author Cuong Nguyen More articles by this author Benjamin Canales More articles by this author Expand All Advertisement PDF downloadLoading ...

The Relationship between Gut Microbiota and Short Chain Fatty Acids in the Renal Calcium Oxalate Stones Disease

Background: The relationship of gut microbiota and calcium oxalate stone has been limited investigated, especially with no study of gut microbiota and short chain fatty acids (SCFAs) in nephrolithiasis. Methods: We provided Sprague Dawley rats of renal calcium oxalate stones with antibiotics and examined the renal crystals deposition. We also performed a case-control study by analyzing 16S rRNA microbial profiling, shotgun metagenomics and SCFAs in 153 fecal samples from non-kidney stone (NS) controls, patients with occasional renal calcium oxalate stones (OS) and patients with recurrent stones (RS). Findings: Antibiotics reduced bacterial load in feces and could promote the formation of renal calcium crystals in model rats. In addition, both OS and RS patients exhibited higher fecal microbial diversity than NS controls. Several SCFAs-producing gut bacteria, as well as metabolic pathways associated with SCFAs production, were considerably lower in the gut microbiota among the kidney stone patients compared with the NS controls. Representation of genes involved in oxalate degradation showed no significance difference among groups. However, fecal acetic acid concentration was the highest in RS patients with high level of urinary oxalate, which was positively correlated with genes involvement in oxalate synthesis. Interpretation: Depletion of gut microbiota promoted the formation of renal crystals. Fecal SCFAs dominant patients, with altered gut microbiota composition and the functional metagenome, were associated with oxalate synthesis. Funding Statement: This work was supported by the National Natural Science Foundation of China [81770703, 81970602]; the Foundation of Science & Technology Department of Sichuan Province [2018SZ0118]; and the 1·3·5 Project for Disciplines of Excellence, West China Hospital, Sichuan University [ZYGD18011, ZYJC18015, ZY2016104]. Declaration of Interests: The authors declare that they have no conflicts of interest. Ethics Approval Statement: The animal experiment was performed in accordance with the policies of the West China Hospital of Sichuan University Medical Research Ethics Committee (2017063A). This study was approved by the West China Hospital of Sichuan University Medical Research Ethics Committee (2018182), and informed consents were obtained from each participant.

ESGCT 27th Annual Congress In collaboration with SETGyc Barcelona, Spain October 22–25, 2019 Abstracts

Xenotransplantation of transgenic porcine pancreatic islets offers a promising alternative source to circumvent current limitations posed by the scarcity of allogeneic donors. We have investigated the feasibility to generate tissue engineered SLA silenced islet cell clusters (ICC) to decrease xenogeneic immune responses Pancreatic islets single cell suspensions were generated by enzymatic digestion of porcine ICCs. Single cells were silenced for SLA expression by lentiviral vectors encoding for Nanoluciferase as reporter gene and for short hairpin RNAs targeting beta2-microglobulin or class II transactivator, respectively. SLA transcripts were evaluated by real-time PCR and protein levels by flow cytometry and fluorescence microscopy analyses. The effect of SLA silencing was evaluated in human T and NK cell cytotoxicity assays. SLA-silenced pancreatic beta-cells were then reassembled into ICCs in stirred bioreactors. SLA class I silencing reached a level of up to 84% and class II by up to 50% on pancreatic islet cell. Silencing SLA expression did not affect cell viability and the insulin-producing beta-cell phenotype. Xenogeneic T-cell immune responses (p < 0.05) as well as antibody-mediated cellular-dependent immune responses (p < 0.01) were significantly decreased. Silencing SLA class I expression did not increase susceptibility to NK-cell cytotoxicity. In stirred bioreactors, tissue engineered islets showing the typical 3D-structure and morphology of ICC were assembled from SLA-silenced pancreatic cell suspensions. These data shows the feasibility to generate low immunogenic porcine ICC from transgenic pigs after single cell engineering and post-transduction islet reassembling that might serve as a robust alternative to allogeneic pancreatic islet cell transplantation.

Clinical and Metabolic Correlates of Calcium Oxalate Stone Subtypes: Implications for Etiology and Management.

Introduction: Calcium oxalate (CaOx) is the predominate component within renal calculi and can be divided into two subtypes: CaOx-monohydrate (COM) and CaOx-dihydrate (COD). COM and COD form in differing urinary environments, which suggest differential underlying metabolic abnormalities associated with each subtype. We compared clinical and metabolic findings in CaOx stone formers to delineate factors differentiating COD and COM stone formers and the implication this holds in terms of etiology and treatment. Patients and Methods: We identified CaOx stone formers that had passed their stones or had undergone endoscopic extraction between October 2014 and December 2018. Only patients who had a predominant subtype (≥80% COM or COD) and who had a 24-hour urine evaluation before medical management were included. Clinical and metabolic factors were compared in the two subgroups. Results: Out of 157 stone formers, 121 were COM and 36 were COD. COD formers were younger than COM formers with a mean age of 53 ± 16 vs 59 ± 15, respectively (p = 0.038). There were no observable differences in gender, body mass index, hypertension, diabetes mellitus, or hyperlipidemia. COM formers exhibited higher rates of hypocitraturia and hyperoxaluria, p = 0.022 and p = 0.018, respectively. Conversely, COD formers had significantly higher rates of hypercalciuria (47% vs 28%, p = 0.012). Multivariate analysis found hypercalciuria to independently predict COD (p = 0.043) and hyperoxaluria to predict COM stones (p = 0.016). Conclusion: COM formers are more likely to have hyperoxaluria, hypocitraturia, and elevated urinary oxalate levels compared to COD formers. COD formers exhibited higher incidence of hypercalciuria. These data suggest that all CaOx stones are not alike and that distinct metabolic and clinical etiological differences exist that may guide future management and prevention.

SUN-325 SAFETY AND EFFICACY OF LUMASIRAN, AN INVESTIGATIONAL RNA INTERFERENCE (RNAi) THERAPEUTIC, IN ADULT AND PEDIATRIC PATIENTS WITH PRIMARY HYPEROXALURIA TYPE 1

Primary hyperoxaluria type 1 (PH1) is a rare genetic disorder characterized by the hepatic overproduction of oxalate, which forms calcium oxalate crystals in the urinary system. Disease manifestations include recurrent urolithiasis, nephrocalcinosis, progressive renal failure, and multi-organ damage from systemic oxalosis, often resulting in high morbidity and mortality. Lumasiran is a subcutaneously-administered investigational RNAi therapeutic specifically designed to reduce a key substrate thereby decreasing oxalate production. The objective is to the present emerging safety and pharmacodynamic data from the Phase 2 open-label extension (OLE) study of lumasiran. ALN-GO1-001 is a Phase 1/2 randomized, placebo-controlled, single-blind, multicenter trial, evaluating lumasiran in patients with PH1 ≥6 years of age with urinary oxalate (UOx) ≥0.7 mmol/1.73m2/day and eGFR >45 mL/min/1.73m2. The study consists of three dosing regimens: 1 mg/kg monthly for 3 doses, 3 mg/kg monthly for 3 doses, or 3 mg/kg lumasiran every 3 months for 2 doses. Once patients complete follow up in Phase 1/2, eligible patients may enroll in the OLE study for long-term dosing. Endpoints for the OLE study include safety and change in 24-hour UOx from baseline. Patients (N=20; 65% females) in Phase 1/2 had a mean age at enrollment of 14.9 years (range 6-43) and a mean baseline UOx of 1.69 mmol/1.73m2/day (range 0.83–2.97). Previously presented data showed no discontinuations or drug-related serious adverse events (AEs). AEs were reported in 3 (100%) patients during placebo dosing and 19 (95%) patients after lumasiran dosing; the majority of AEs were mild or moderate and deemed unrelated to study drug. Mean maximal reduction in urinary oxalate relative to baseline was 75% after lumasiran dosing; the mean reduction relative to baseline 28 days post last dose of lumasiran was 66%. Among patients receiving lumasiran 3.0 mg/kg monthly or quarterly, 10/12 (83%) achieved urinary oxalate levels within the normal range (<0.46 mmol/1.73m2/day). As of Oct 2018, all patients who have completed follow up in Phase 1/2 have enrolled in the OLE. At the time of data cut off, patients (N=8) have been on the OLE study for 2.7 months (range: 0.03–3.02). Safety data from OLE remains consistent with that observed in the Phase 1/2 study, with no discontinuations or drug related serious adverse events. AEs were reported in 5 (63%) of patients; all AEs were mild or moderate in severity and a majority were unrelated to study drug. The acceptable safety profile and clinically significant reduction in urinary oxalate levels observed in these studies support continued clinical development of lumasiran for patients with PH1. A Phase 3 program to evaluate the efficacy and safety of lumasiran in children and adults with primary hyperoxaluria type 1 is now underway.

Anticalcifying effect of Daucus carota in experimental urolithiasis in Wistar rats

BackgroundUrolithiasis is a burgeoning disease that results from pathological biomineralization. Daucus carota L. is a widely consumed food crop with reported nephroprotective and diuretic activity. Its potential for Ashmari bhedan (destruction of stone/calculi) or treatment of urinary calculi has been explored traditionally. However, no scientific evidence is available to prove its antiurolithiatic efficacy. Moreover, establishing the antiurolithiatic effects of D. carota, an extensively consumed commodity with numerous health benefits, would provide a beneficial dietary measure for the prevention and cure of urolithiasis. ObjectiveThe study aimed at investigating in vivo antiurolithiatic potential of hydroethanolic extract of D. carota roots against calcium oxalate urolithiasis. Materials and methodsEthylene glycol and ammonium chloride induced hyperoxaluria model of urolithiasis in male Wistar rats was used for the study. Urine and serum parameters and, kidney histopathology was used to determine the antilithic efficacy of D. carota root extract. ResultsD. carota extract significantly ameliorated abnormal urinary levels of calcium, oxalate, phosphate, magnesium, citrate, protein and uric acid in lithogenic rats. Serum BUN, creatinine and uric acid levels; and calcium, phosphate and oxalate deposition in kidney tissue were also rendered normal following D. carota treatment. D. carota extract also prevented oxidative stress mediated renal tissue degeneration both prophylactically and curatively. ConclusionThis study suggests antiurolithiatic effect of D. carota roots, which can be attributed to its anticrystallization property, ability to ameliorate urine and serum biochemistry and renal cellularity.

PD12-01 ASSOCIATION OF OBESITY WITH INCREASED ENDOGENOUS OXALATE SYNTHESIS

INTRODUCTION AND OBJECTIVES:Urinary oxalate levels are affected by both dietary and endogenous components. Prior studies have demonstrated the positive correlation between weight/body mass index (B...

Fecal transplant modifies urine chemistry risk factors for urinary stone disease.

Urinary stone disease (USD) is a major health concern. There is a need for new treatment modalities. Recently, our group provided evidence for an association between the GMB composition and USD. The accessibility of the Gut Microbiome (GMB) makes it an attractive target for investigation and therefore, in these studies we have evaluated the extent to which the whole gut microbial community in fecal transplants can affect urinary stone risk parameters in an animal model. Fresh fecal pellets were collected from Zucker lean rats, homogenized in PBS (100 mg/mL), filtered through a 70 μm strainer and then orally gavaged into C57BL/6NTac germ‐free mice. Twenty‐four hours urine collections and GMB analysis were performed over time for 1 month. Kidney and gut tissue were harvested from transplanted mice for western blot analysis of expression levels of the Slc26a6 transporter involved in oxalate balance. Urinary calcium decreased after fecal transplant by 55% (P < 0.001). Urinary oxalate levels were on average 24% lower than baseline levels (P < 0.001). Clostridiaceae family was negatively correlated with urinary oxalate at 4 weeks after transplant (r = −0.83, P < 0.01). There was a 0.6 unit average increase in urinary pH from a baseline of 5.85 (SE ± 0.028) to 6.49 (SE ± 0.04) (P < 0.001) after transplant. There was a concomitant 29% increase in gastrointestinal alkali absorption (P < 0.001) 4‐weeks after fecal transplant. Slc26a6 expression increased by 90% in the cecum after transplant. Our results suggest that the gut microbiome may impact metabolism, alters urinary chemistry, and thereby may influence USD; the accessibility of the GMB can potentially be leveraged for therapeutic interventions.

Systemic Alanine Glyoxylate Aminotransferase mRNA Improves Glyoxylate Metabolism in a Mouse Model of Primary Hyperoxaluria Type 1.

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-/- mice. Repeat dosing in Agxt-/- mice resulted in a 40% reduction in urinary oxalate, suggesting therapeutic benefit. These studies suggest that mRNA encoding AGT led to increased expression and activity of the AGT enzyme in liver that translated into decrease in urinary oxalate levels. Taken together, our data indicate that AGT mRNA may have the potential to be developed into a therapeutic for PH1.

Does the Urinary Calcium/Citrate Ratio Add to the Diagnostic Workup of Children at Risk of Kidney Stones? A Cross-Sectional Study

The purpose of the study was to evaluate urinary citrate/creatinine (UCi/UCr) and urinary calcium/citrate (UCa/UCi) ratios for distinguishing stone formers (SF) from non-stone formers (NSF) in an at-risk population. This was a retrospective study that included all pediatric patients who underwent urinary citrate testing from April 2017 to March 2018. The urinary levels of citrate, calcium, sodium, potassium, creatinine, oxalate, urate, pH, and specific gravity (SG) were measured in our clinical laboratory. Diagnosis of kidney stones was obtained through chart review.A total of 97 patients were included (46 NSF and 51 SF). The UCi/UCr ratio was not significantly different between NSF and SF. Median UCa/UCr ratio was higher in SF (0.67) compared with NSF (0.21, p &lt; 0.0001). The median ratio of UCa/UCi was also higher in SF (1.30) than in NSF (0.65, p = 0.001). Oxalate, urate, pH, SG, and urinary sodium/potassium ratio did not differentiate between the SF and NSF. Positive correlation was seen between UCa/UCr and urinary sodium/creatinine UNa/UCr (p &lt; 0.0001), as well as between UCa/UCr and UCi/UCr (p &lt; 0.0001).The study has demonstrated significantly higher UCa/UCi and UCa/UCr in SF compared with NSF, while the use of urinary oxalate, urate, pH, and SG did not differentiate between SF from NSF. We also confirmed a positive correlation between UNa/UCr and UCa/UCr. While the utility of UCa/UCr is well established, our data suggest that UCa/UCi rather than UCi/UCr may be more predictive in the clinical setting when evaluating for nephrolithiasis.