Oxalate Levels Research Articles

High Plasma Oxalate Levels Early After Kidney Transplantation Are Associated With Impaired Long-Term Outcomes.

Background: Elevated levels of oxalate are common in renal failure patients and non-hyperoxaluria disease, and may cause damage after transplantation. We examined outcomes after 15 years for 167 kidney transplant recipients who had plasma oxalate measured early after transplantation. Analyses included plasma oxalate, recipient age, donor age, live donor, HLA-DR mismatch, mGFR, and smoking. Results: Median age was 52 years (range 18–81), 63% were male and 38% had live donors. Median plasma oxalate concentration 10 weeks after transplantation was 9.0 μmol/L (range 2.7–53.0), one third above the upper reference limit (11.0 μmol/L). Multivariable analysis revealed upper quartile plasma oxalate (>13.0 μmol/L, p = 0.008), recipient age (p < 0.001), deceased donor (p = 0.003), and current smoking (p < 0.001) as significant factors associated with patient survival. Upper quartile plasma oxalate (p = 0.021), recipient age (p = 0.001), deceased donor kidney (p = 0.001), HLA-DR mismatch (p = 0.015), and current smoking (p = 0.014) were also associated with graft loss. Factors associated with death censored graft losses were donor age (p = 0.012), deceased donor (p = 0.032), and HLA-DR mis-matched kidneys (p = 0.005) but plasma oxalate was not (p = 0.188). Conclusions: Plasma oxalate in the upper quartile early after transplantation was significantly associated with impaired long-term patient survival and graft losses, but not when censored for death.

In vivo CRISPR-Cas9 inhibition of hepatic LDH as treatment of primary hyperoxaluria

Genome-editing strategies, especially CRISPR-Cas9 systems, have substantially increased the efficiency of innovative therapeutic approaches for monogenic diseases such as primary hyperoxalurias (PHs). We have previously demonstrated that inhibition of glycolate oxidase using CRISPR-Cas9 systems represents a promising therapeutic option for PH type I (PH1). Here, we extended our work evaluating the efficacy of liver-specific inhibition of lactate dehydrogenase (LDH), a key enzyme responsible for converting glyoxylate to oxalate; this strategy would not be limited to PH1, being applicable to other PH subtypes. In this work, we demonstrate a liver-specific inhibition of LDH that resulted in a drastic reduction of LDH levels in the liver of PH1 and PH3 mice after a single-dose delivery of AAV8 vectors expressing the CRISPR-Cas9 system, resulting in reduced urine oxalate levels and kidney damage without signs of toxicity. Deep sequencing analysis revealed that this approach was safe and specific, with no off-targets detected in the liver of treated animals and no on-target/off-tissue events. Altogether, our data provide evidence that in vivo genome editing using CRISPR-Cas9 systems would represent a valuable tool for improved therapeutic approaches for PH.

Effect of fermentation and drying on the nutrient and antinutrient composition of yellow and white maize flours

Background: Maize is the most abundant and available component of the locally prepared gruels for human consumption in Nigeria. It has been the basic source of meal for infants and breakfast for the average family. Pap in its current state cannot be stored at home for an extended period of time without spoiling or becoming contaminated.&#x0D; Aim: The aim of this research was to investigate and compare the effect of fermentation and drying on the nutrient and antinutrient composition of the sieved and unsieved yellow and white maize flour.&#x0D; Methods: The gains were divided into two portions and fermented for 48hrs. One portion was wet milled and sieved while the other portion was wet milled and unsieved. The slurries gotten were air- dried and sun-dried. The flours were analysis for proximate, vitamins minerals and antinutrient using standard methods.&#x0D; Result: The study revealed that air dried unsieved yellow maize had an increased in protein, fibre and carbohydrate content of the flours while sun dried unsieved had an increase in fat, and ash. The air dried unsieved yellow flours had an increase in the minerals (calcium, iron and phosphorous) and vitamins (Vit A, Vit C and folate) content increased due to fermentation and unsieving. The tannin, phytate and oxalate levels were drastically reduced in the dried flours.&#x0D; Conclusion: The yellow fermented unsieved air dried maize facilitates increased accessibility of nutrient and reduced anti-nutrient. Fermented unseived maize flour could therefore be used be adopted for preparation of maize pap.

Atmospheric Chemistry of Oxalate: Insight Into the Role of Relative Humidity and Aerosol Acidity From High‐Resolution Observation

AbstractOxalate is the product of the precursors that can eventually be oxidized into oxalate by atmospheric oxidants (O3, etc.) and then redistributed to the particle phase, which has an impact on acid rain, and even the climate. However, we are still unclear about the influence of typical atmospheric oxidants in different phases with different RH and pH on oxalates. Here, we analyzed the effects of typical oxidants at RH ≤ 30%, 30% &lt; RH ≤ 80% of the atmosphere on oxalates in atmospheric particulates based on high‐resolution online observation in Nanjing: the chemical processes of O3, OX (=O3 + NO2), and Cl− in different RH all have an important influence on the oxalate level, especially at 30% &lt; RH ≤ 80% with high humidity have greater influence. NO2 only affects the particulate oxalate at RH ≤ 30%; HONO shows a greater effect at RH ≤ 30%, and 30% &lt; RH ≤ 80% in winter and summer, the atmospheric oxidants that dust participates in have little effect. At the same time, we also found the difference between the influence of pH on atmospheric oxalate in winter and summer at RH &gt; 80%, among which high pH is beneficial to the formation of oxalate in summer, while in winter has a greater influence on oxalate at RH ≤ 30%. These results help us to systematically understand the influence and distribution of oxalate in the atmosphere by RH, pH, and typical atmospheric oxidants.

Oxalobacter formigenes treatment confers protective effects in a rat model of primary hyperoxaluria by preventing renal calcium oxalate deposition.

In primary hyperoxaluria, increased hepatic oxalate production sometimes leads to severe nephrocalcinosis and early end-stage kidney disease. Oral administration of Oxalobacter formigenes (O. formigenes), an oxalate-degrading bacterium, is thought to derive oxalate from systemic sources by inducing net enteric oxalate secretion. Here, the impact of O. formigenes on nephrocalcinosis was investigated in an ethylene glycol rat model mimicking hepatic oxalate overproduction in primary hyperoxaluria. Eighteen rats were administered ethylene glycol (0.75% in drinking water) for 6weeks, of which 9 were treated by oral gavage with O. formigenes and 9 received vehicle. Five control rats did not receive ethylene glycol or O. formigenes. Plasma and urinary oxalate levels, calcium oxalate crystalluria, urinary volume, fluid intake, and serum creatinine were monitored during the study. On killing, nephrocalcinosis was quantified. Ethylene glycol intake induced pronounced hyperoxalemia, hyperoxaluria, calcium oxalate crystalluria and nephrocalcinosis. Concomitant O. formigenes treatment partially prevented the ethylene glycol-induced increase in plasma oxalate and completely prevented nephrocalcinosis. Urinary oxalate excretion was not reduced by O. formigenes treatment. Nevertheless, absence of crystals in renal tissue of O. formigenes-treated ethylene glycol animals indicates that the propensity for oxalate to crystallize in the kidneys was reduced compared to non-treated animals. This is supported by the lower plasma oxalate concentrations in O. formigenes-treated animals. This study shows a beneficial effect of O. formigenes treatment on ethylene glycol-induced hyperoxalemia and nephrocalcinosis, and thus supports a possible beneficial effect of O. formigenes in primary hyperoxaluria.

POS-461 CREATION OF RATIONALLY DESIGNED AND METABOLICALLY ACTIVE MICROBIOME CONSORTIA FOR TREATMENT OF ENTERIC HYPEROXALURIA

Enteric hyperoxaluria (EH) is caused by excess absorption of dietary oxalate leading to elevated urinary oxalate (UrOx) levels. Once absorbed, oxalate can complex with calcium to form insoluble crystals, and as a result chronically elevated UrOx levels are a major risk factor for the development of kidney stones and progression to kidney damage. There are currently no approved therapies for EH; the standard of care options is limited to supportive measures and dietary restrictions that have relatively low compliance.

POS-433 SYSTEMIC MANIFESTATIONS OF PRIMARY HYPEROXALURIA IN ADULT PATIENTS: A MONOCENTRIC TUNISIAN STUDY

Primary hyperoxaluria (PH) is a rare recessive autosomic condition. It is related to an enzymatic deficit in alanine glyoxylate aminotransferase (AGXT) leading to increased oxalate levels in the body. Uncontrolled production of insoluble calcium oxalate induces its deposition in several tissues, mainly in the kidneys.

Structural identification through GC mass spectrophotometer and determine anti lithiotic activity of hibiscus rosa sinensis by using ethylene glycol induced method

The present study investigated the antiurolithiatic effect of standardized ethanolic extract of Hibiscus rosa sinensis by structural elucidation of the responsible compound for the activity as well as Ethylene glycol model induce calcium oxalate crystal in Albino rats. The chemical structural elucidation of H. rosa sinensis performed by phytochemical study and GC-Mass spectrophotometry. Calcium oxalate urolithiasis was induced in rats in rats by ethylene glycol -ammonium chloride feeding in drinking water. Antiurolithiatic activity of H. rosa sinensis was evaluated in 2 different doses (300,600 mg/kg) in curative and preventive regimen by estimating the histological changes in kidney and biochemical change in urine, serum. Sodium oxalate was used as reference standard drug. Ethylene glycol-ammonium chloride feeding caused an increase in urinary volume, oxalate, total protein, phosphate and uric acid levels along with a decrease in urinary excretion of calcium, magnesium and citrate. Test group -1 and Test group-2 animals treated with H. rosa sinensis decrease the amount of calcium, oxalate, citrate, which is responsible for induce calcium oxalate crystals in significant amount. Histological study revealed minimum damage and a smaller number of calcium oxalate deposits in the kidney of ethylene glycol treated rats. These results indicated that the hibiscus rosa sinensis reduced and prevented the growth of urinary stones. However, the sodium citrate is more effective than the H rosa sinensis (600 mg/kg more effective than hibiscus 300 mg/kg) in the treatment of urolithiasis. Keywords: Hibiscus Rosa Sinensis, Kidney Stone, Sodium Citrate, Ethylene Glycol, Calcium Oxalate.

Ultra-Low-Dose Pre-Metallation Strategy Served for Commercial Metal-Ion Capacitors

HighlightsInterfacial bonding strategy has been successfully applied to address the high overpotential issue of sacrificial additives, which reduced the decompositon potential of Na2C2O4 from 4.50 to 3.95 V.Ultra-low-dose technique assisted commercial sodium ion capacitor (AC//HC) could deliver a remarkable energy density of 118.2 Wh kg−1 as well as excellent cycle stability.In-depth decomposition mechanism of sacrificial compound and the relative influence after pre-metallation were revealed by advanced in situ and ex situ characterization approaches.Sacrificial pre-metallation strategy could compensate for the irreversible consumption of metal ions and reduce the potential of anode, thereby elevating the cycle performance as well as open-circuit voltage for full metal ion capacitors (MICs). However, suffered from massive-dosage abuse, exorbitant decomposition potential, and side effects of decomposition residue, the wide application of sacrificial approach was restricted. Herein, assisted with density functional theory calculations, strongly coupled interface (M–O–C, M = Li/Na/K) and electron donating group have been put forward to regulate the band gap and highest occupied molecular orbital level of metal oxalate (M2C2O4), reducing polarization phenomenon and Gibbs free energy required for decomposition, which eventually decrease the practical decomposition potential from 4.50 to 3.95 V. Remarkably, full sodium ion capacitors constituted of commercial materials (activated carbon//hard carbon) could deliver a prominent energy density of 118.2 Wh kg−1 as well as excellent cycle stability under an ultra-low dosage pre-sodiation reagent of 15–30 wt% (far less than currently 100 wt%). Noteworthily, decomposition mechanism of sacrificial compound and the relative influence on the system of MICs after pre-metallation were initially revealed by in situ differential electrochemical mass spectrometry, offering in-depth insights for comprehending the function of cathode additives. In addition, this breakthrough has been successfully utilized in high performance lithium/potassium ion capacitors with Li2C2O4/K2C2O4 as pre-metallation reagent, which will convincingly promote the commercialization of MICs.

ANTIUROLITHIATIC ACTIVITY OF ETHANOLIC EXTRACT OF EICHHORNIA CRASSIPES (MART.) SOLMS WHOLE PLANT ON ETHYLENE GLYCOL-INDUCED UROLITHIASIS IN WISTAR RATS

Objective: In India Indigenous system of medicine, the plant Eichhornia crassipes (Mart.) Solms is claimed to be useful for different ailments. The purpose of this study is to investigate the significant activity of the ethanolic extract of E. crassipes (Mart.) Solms whole plant in the treatment of renal stone by ethylene glycol (EG)-induced urolithiasis in Wistar rats. Methods: Wistar rat will be divided into four groups. All the animals received EG 0.75%v/v by orally for 28 days. Group I was received 0.75%v/v EG for 28 days. Groups II, III, and IV were received cystone, ethanolic extract of E. crassipes (Mart.) Solms (200 mg/kg, and 400 mg/kg), respectively, administered orally from 15th to 28th day for curative regimen. Animals were housed in metabolic cages and collect the 24 h urine samples and serum samples on the 7th, 14th, 21th, and 28th day of the experiments. Under the microscopical study to observe the crystals in urine sample. The biochemical parameters monitored in the present study are calcium, oxalate, magnesium, phosphorus, urea, creatinine, uric acid, blood urea nitrogen (BUN), and lactate dehydrogenase (LDH) in urine and serum samples. Results: The EG feeding resulted in elevated renal excretion of calcium, phosphate, oxalate, and decreased renal excretion of magnesium as well-elevated serum BUN, creatinine, uric acid, urea, LDH levels, and decreased the urine pH and urine volume. Treatment of the ethanolic extract of E. crassipes (Mart.) Solms significantly reduced the elevated calcium, phosphate, oxalate in urine as well as BUN, creatinine, uric acid, urea, and LDH level in serum. It also restores the normal urine pH and promotes the urine output. Conclusion: Ethanolic extract of E. crassipes (Mart.) Solms exhibited significant anti-urolithiatic activity evident from urine calcium, phosphate, oxalate levels and serum BUN, creatinine, uric acid, urea and LDH levels.

Molecular mechanism of Pyrrosia lingua in the treatment of nephrolithiasis: Network pharmacology analysis and in vivo experimental verification

BackgroundEvidence exists reporting that Pyrrosia lingua (PL, Xinhui Pharmaceutical, Polypodiaceae) alleviates nephrolithiasis in rat models. The precipitation of calcium oxalate may result in kidney stones, and the intestinal microbiota is critical for oxalate metabolism. Therefore, we attempt to delineate the molecular mechanism underlying the effect of PL on nephrolithiasis and its association with gut microbiota. MethodsFollowing differential flora analysis in gutMEGA, the network relationship of PL and nephrolithiasis was analyzed based on the TCMSP, DisGeNET and STRING databases. Moreover, the kidney stone model rats were fed with different doses of PL powder and PL extract. In addition, metabolomics technology was employed to identify the active ingredients in PL extract and the microbial metabolites in rat feces. ResultsThe effect of PL on the nephrolithiasis was based on quercetin and kaempferol by mediating the toll-like receptor signaling pathway and regulating the expression levels of interleukin 6, tumor necrosis factor, mitogen activated protein kinase 8, and secreted phosphoprotein 1. PL significantly reduced the levels of urine oxalic acid, urine calcium, and osteopontin (OPN) levels in rat models of nephrolithiasis. Notably, PL extract decreased these two indicators to lower levels. Furthermore, contents of Oxalobacter formigenes, Bacteriodetes, Bifidobacterium and Fecalibacterium were obviously reduced after treatment with PL extract. ConclusionPL powder and its active extracts reduce the oxalate level in urine by regulating oxalate metabolism, thus ameliorating the damage of kidney tissues and preventing kidney stone formation. This study suggests the use of PL and its extracts as an alternative source of promising agents that might directly or indirectly inhibit the progression of kidney stone diseases.

Inhibition of Toxic Effects of Oxalate in Sugar Beet Pulp with Adding Ca During Ensiling

This study was carried out to eliminate the toxic effect of soluble oxalate in sugar beet pulp (SBP) by ensiling and adding Ca during ensiling and to determine the effects of the obtained silage on sheep. The study was based on two experiments. For the first experiment, the laboratory silages were prepared as SBP alone with the addition of molasses and straw at different levels of dry matter and Ca. After fermentation for 120 days, the Fleig scores, physical properties, Weende analysis, and oxalate analysis were performed. This laboratory trial showed that the content of the soluble oxalate could be reduced to nontoxic levels by ensiling and adding Ca. For the second experiment, SBP silage with 30% dry matter (DM) and 45 mg/kg SBP were prepared according to the results of the first experiment. This silage was fed to 36 sheep divided into six groups. During the experiment, blood samples and rumen fluid was collected every 14 days during the experiment, and the body weights were controlled. The results of this experiment showed that the soluble oxalate amount of SBP decreased to a tolerable level by the rumen. Thus, ensiling SBP with barley straw, molasses, urea, and di-calcium phosphate (DCP), as a calcium source, showed that soluble oxalate levels of SBP could be reduced levels below the toxic levels, and added to sheep ratio as 60%.

Hyperoxaluria: An early diagnosis will allow a timely combined renal and liver transplantations to avoid irreversible damages to all other organs.

ABSTRACTA 4-month-old patient was admitted to the emergency room for vomiting, weight gain, food refusal and hypertension. Blood gases showed a metabolic acidosis with increased anion gap. Laboratory finding revealed severe renal failure (creatinine 8 mg/dL). Renal ultrasound showed an important hyperechogenicity of the parenchyma with loss of cortico-medullar differentiation suggesting a nephronophytosis. Genetic testing was negative. Urine oxalate levels were increased to 140 μmol/L. New genetic tests were positive for type I hyperoxaluria. The authors discuss the management of hyperoxaluria.

Endogenous Oxalate Production in Primary Hyperoxaluria Type 1 Patients.

Primary hyperoxaluria type 1 (PH1) is an inborn error of glyoxylate metabolism, characterized by increased endogenous oxalate production. The metabolic pathways underlying oxalate synthesis have not been fully elucidated, and upcoming therapies require more reliable outcome parameters than the currently used plasma oxalate levels and urinary oxalate excretion rates. We therefore developed a stable isotope infusion protocol to assess endogenous oxalate synthesis rate and the contribution of glycolate to both oxalate and glycine synthesis in vivo . Eight healthy volunteers and eight patients with PH1 (stratified by pyridoxine responsiveness) underwent a combined primed continuous infusion of intravenous [1- 13 C]glycolate, [U- 13 C 2 ]oxalate, and, in a subgroup, [D 5 ]glycine. Isotopic enrichment of 13 C-labeled oxalate and glycolate were measured using a new gas chromatography-tandem mass spectrometry (GC-MS/MS) method. Stable isotope dilution and incorporation calculations quantified rates of appearance and synthetic rates, respectively. Total daily oxalate rates of appearance (mean [SD]) were 2.71 (0.54), 1.46 (0.23), and 0.79 (0.15) mmol/d in patients who were pyridoxine unresponsive, patients who were pyridoxine responsive, and controls, respectively ( P =0.002). Mean (SD) contribution of glycolate to oxalate production was 47.3% (12.8) in patients and 1.3% (0.7) in controls. Using the incorporation of [1- 13 C]glycolate tracer in glycine revealed significant conversion of glycolate into glycine in pyridoxine responsive, but not in patients with PH1 who were pyridoxine unresponsive. This stable isotope infusion protocol could evaluate efficacy of new therapies, investigate pyridoxine responsiveness, and serve as a tool to further explore glyoxylate metabolism in humans.

Hyperoxaluria: An early diagnosis will allow a timely combined renal and liver transplantations to avoid irreversible damages to all other organs

ABSTRACT A 4-month-old patient was admitted to the emergency room for vomiting, weight gain, food refusal and hypertension. Blood gases showed a metabolic acidosis with increased anion gap. Laboratory finding revealed severe renal failure (creatinine 8 mg/dL). Renal ultrasound showed an important hyperechogenicity of the parenchyma with loss of cortico-medullar differentiation suggesting a nephronophytosis. Genetic testing was negative. Urine oxalate levels were increased to 140 μmol/L. New genetic tests were positive for type I hyperoxaluria. The authors discuss the management of hyperoxaluria.

The Relationship between Modern Fad Diets and Kidney Stone Disease: A Systematic Review of Literature.

Objectives: Kidney stone disease (KSD) has a strong association with diet metabolic syndrome. This review aims at exploring the lithogenic risk posed by the current most popular diets. Our approach was to search for the effect of each diet type on the major urinary risk factors, to try to draw conclusions regarding the association of a specific diet type and KSD. Methods: This systematic review searched for the available literature exploring the association between the existing popular fad diets and KSD. Articles in English, French and Spanish were included, without restriction of the search period with the final search done in August 2021. Results: Total number of studies and studies for each diet type was as follows: 22 articles for the low carbohydrate diet, 20 articles for high protein diets, 26 articles for vegetarian and vegan diets. There exists a substantial variability in different low carbohydrate and high protein diets, and considerable overlap between modern popular fad diets. High carbohydrate intake might increase urine uric acid, calcium and oxalate levels. High protein diets increase urine calcium and uric acid and lower urine pH and citrate. Consumption of fruits and vegetables increases the urinary volume and urinary citrate. In vegan diets, sufficient daily calcium intake is important to avoid possible secondary hyperoxaluria. Conclusions: Few studies evaluated the direct relationship between modern fad diets and KSD. In general, the reduction of carbohydrate in the diet, and counterbalancing protein rich diets with sufficient intake of fruits and vegetables, seem to play a protective role against KSD formation. Maintaining sufficient calcium intake in vegan and vegetarian diets is important. Additional research is needed to directly evaluate the link between KSD and each diet type.

Role of Citrus Fruit Juices in Prevention of Kidney Stone Disease (KSD): A Narrative Review.

To explore the relationship between citrus fruit juices (oranges, grapefruits, and lemonades) and kidney stone disease (KSD). Methods: A systematic review was performed using the Medline, EMBASE, and Scopus databases, in concordance with the PRISMA checklist for all English, French, and Spanish language studies regarding the consumption of citrus fruit juices and the relationship to urinary stone disease. The main outcome of interest was the association of citrus fruit juices with KSD. Results: Thirteen articles met the criteria for inclusion in the final review. Three large epidemiological studies found that grapefruit juice was a risk factor for stone formation, while orange juice did not increase the risk for KSD. Ten small prospective clinical studies found that orange, grapefruit, and lemon juices all increased urinary citrate levels. Only orange and grapefruit juices had an alkalinizing effect and while lemon juice has a protective effect by raising urinary citrate levels, it lacked a significant alkalinizing effect on urine pH. Orange juice and grapefruit juices significantly increased urinary oxalate levels, while orange juice also had a high carbohydrate content. Conclusion: While orange juice seems to play a protective role against stone formation, grapefruit was found to raise the risk of KSD in epidemiological studies but had a protective role in smaller clinical studies. Lemon juice had a smaller protective role than orange juice. Larger amounts of, as well as more accurate, data is needed before recommendations can be made and a high carbohydrate content in these juices needs to be taken into consideration.

Short-Chain Fatty Acids Reduced Renal Calcium Oxalate Stones by Regulating the Expression of Intestinal Oxalate Transporter SLC26A6.

ABSTRACTRenal calcium oxalate (CaOx) stone is a common urologic disease with a high prevalence and recurrence rate. However, short-chain fatty acids (SCFAs) are less often reported in the prevention of urolithiasis. This study aimed to explore the effect of SCFAs on the renal CaOx stone formation and the underlying mechanisms. Ethylene glycol was used to induce renal CaOx crystals in rats. SCFAs (acetate, propionate, or butyrate) were added as supplements to the drinking water with or without antibiotics. Because intestinal oxalate transporters SLC26A6 and SLC26A3 regulate the excretion and absorption of oxalate in the intestine, we injected adeno-associated virus 9 (AAV9)-SLC26A6-shRNA (short hairpin RNA) and AAV9-SLC26A3 into the tail vein of rats to suppress SLC26A6 and overexpress SLC26A3 expression in the intestine, respectively, to explore the role of SLC26A3 and SLC26A6 (SLC26A3/6) in the reduction of renal CaOx crystals induced by SCFAs. Results showed that SCFAs reduced renal CaOx crystals and urinary oxalate levels but, however, increased the abundance of SCFA-producing bacteria and cecum SCFA levels. SCFA supplements still reduced renal crystals and urinary oxalate after gut microbiota depletion. Propionate and butyrate downregulated intestinal oxalate transporter SLC26A3 expression, while acetate and propionate upregulated SLC26A6 expression, both in vivo and in vitro. AAV9-SLC26A3 exerted a protective effect against renal crystals, while AAV9-SLC26A6-shRNA contributed to the renal crystal formation even though the SCFAs were supplemented. In conclusion, SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.IMPORTANCE Some studies found that the relative abundances of short-chain-fatty-acid (SCFA)-producing bacteria were lower in the gut microbiota of renal stone patients than healthy controls. Our previous study demonstrated that SCFAs could reduce the formation of renal calcium oxalate (CaOx) stones, but the mechanism is still unknown. In this study, we found that SCFAs (acetate, propionate, and butyrate) reduced the formation of renal calcium oxalate (CaOx) crystals and the level of urinary oxalate. Depleting gut microbiota increased the amount of renal crystals in model rats, and SCFA supplements reduced renal crystals and urinary oxalate after gut microbiota depletion. Intestinal oxalate transporter SLC26A6 was a direct target of SCFAs. Our findings suggested that SCFAs could reduce urinary oxalate and renal CaOx stones through the oxalate transporter SLC26A6 in the intestine. SCFAs may be new supplements for preventing the formation of renal CaOx stones.

Nephroprotective Effect of Functional Beverage of Dolichous Biflorus Seeds on Ethylene Glycol Induced Urolithiasis: A Mechanistic Approach

Calcium oxalate is the most common type of urolithiasis and is suggested due to membrane oxalate transporters dysfunction. This study has used Dolichos biflorus seeds as a functional beverage to explore its bioactive substances’ role on membrane transporters for managing urolithiasis. Urolithiasis model of ethylene glycol induced calcium oxalate crystals in albino Wistar rats was used in this study. Treatment of functional beverage of Dolichos biflorus seeds restored normal blood and urinary oxalate and citrate level and showed anti-urolithiasis activity. Probenecid, a membrane organic anion transporter (Slc26) inhibitor, treatment has abolished anti-urolithiasis activity of functional beverage and suggested Dolichos biflorus produce effect through the restoration of membrane oxalate transporters activity. An oxalate-less diet did not significantly reduce urinary, and plasma oxalate in probenecid treated animals and suggested that dietary oxalate is not primarily involved in calcium oxalate urolithiasis and conditions like hyperoxalemia and hyperoxaluria. Therefore, our findings suggested that endogenous oxalate in conjunction with idiopathic or chronic reduced activity or defective Slc26 transporters due to aging results in calcium oxalate kidney stones. The functional beverage of Dolichos biflorus seeds exhibited anti-urolithiasis activity through improving the activity of Slc26 transporters.

Optimization Process to Increase the Quality of Lombok Porang Flour

As a primary source of glucomannan, porang (Amorphophallus oncophyllus Prain) has a decisive role in the food and non-food industry development. However, the naturally high calcium oxalate content in the corm is one obstacle why it is not safe as a food material. This paper describes and discusses the optimizing process to reduce the level of calcium oxalate content and improve the quality of the flour of porang locally grown in Lombok. Porang samples were obtained from the center of growing area in North Lombok. Series of trials were carried out, including treatment using a salt solution, blanching, and fermentation technology. The parameters observed in this study were the calcium oxalate content, moisture content, and the color of porang flour. The results from these trials indicated that soaking in salt solution and blanching technology significantly reduced the calcium oxalate concentration in the flour. However, the oxalate levels in the flour were slightly higher than the quality standard requirement. In contrast, fermentation treatment was not effective in reducing the oxalate level. In general, all treatments significantly reduced the flour-moisture content. Further research is required in order to produce quality local porang flour that meets quality standards.