Sex-specific Stone-forming Phenotype in Mice During Hypercalciuria/Urine Alkalinization.

Sex differences in kidney stone formation are well known. Females generally have slightly acidic blood and higher urine pH when compared with males, which makes them more vulnerable to calcium stone formation, yet the mechanism is still unclear. We aimed to examine the role of sex in stone formation during hypercalciuria and urine alkalinization through acetazolamide and calcium gluconate supplementation, respectively, for 4 weeks in wild-type (WT) and moderately hypercalciuric [TRPC3 knockout [KO](-/-)] male and female mice. Our goal was to develop calcium phosphate (CaP) and CaP+ calcium oxalate mixed stones in our animal model to understand the underlying sex-based mechanism of calcium nephrolithiasis. Our results from the analyses of mice urine, serum, and kidney tissues show that female mice (WT and KO) produce more urinary CaP crystals, higher [Ca2+], and pH in urine compared to their male counterparts. We identified a sex-based relationship of stone-forming phenotypes (types of stones) in our mice model following urine alkalization/calcium supplementation, and our findings suggest that female mice are more susceptible to CaP stones under those conditions. Calcification and fibrotic and inflammatory markers were elevated in treated female mice compared with their male counterparts, and more so in TRPC3 KO mice compared with their WT counterparts. Together these findings contribute to a mechanistic understanding of sex-influenced CaP and mixed stone formation that can be used as a basis for determining the factors in sex-related clinical studies.

Inhibitory effect of Incarvillea diffusa Royle extract in the formation of calcium oxalate nephrolithiasis by regulating ROS-induced Nrf2/HO-1 pathway in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Calcium oxalate (CaOx) kidney stones are widely acknowledged as the most prevalent type of urinary stones, with high incidence and recurrence rates. Incarvillea diffusa Royle (ID) is a traditionally used medicinal herb in the Miao Minzu of Guizhou province, China, for treating urolithiasis. However, the active components and the underlying mechanism of its pharmacodynamic effects remain unclear. AIM OF THE STUDY: This study aimed to investigate the potential inhibitory effect of the active component of ID on the formation of CaOx nephrolithiasis and elucidate the underlying mechanism. MATERIALS AND METHODS: In vivo, a CaOx kidney stone model was induced in Sprague-Dawley (SD) rats using an ethylene glycol and ammonium chloride protocol for four weeks. Forty-eight male SD rats were randomly assigned to 6 groups (n = 8): blank group, model group, apocynin group, and low, medium, and high dose of ID's active component (IDW) groups. After three weeks of administration, rat urine, serum, and kidney tissues were collected. Renal tissue damage and crystallization, Ox, BUN, Ca2+, CRE, GSH, MDA, SOD contents, and levels of IL-1ß, IL-18, MCP-1, caspase-1, IL-6, and TNF-α in urine, serum, and kidney tissue were assessed using HE staining and relevant assay kits, respectively. Protein expression of Nrf2, HO-1, p38, p65, and Toll-4 in kidney tissues was quantified via Western blot. The antioxidant capacities of major compounds were evaluated through DPPH, O2·-, and ·OH radical scavenging assays, along with their effects on intracellular ROS production in CaOx-induced HK-2 cells. RESULTS: We found that IDW could significantly reduce the levels of CRE, GSH, MDA, Ox, and BUN, and enhancing SOD activity. Moreover, it could inhibit the secretion of TNF-α, IL-1ß, IL-18, MCP-1, caspase-1, and decreased protein expression of Nrf2, HO-1, p38, p65, and Toll-4 in renal tissue. Three major compounds isolated from IDW exhibited promising antioxidant activities and inhibited intracellular ROS production in CaOx-induced HK-2 cells. CONCLUSIONS: IDW facilitated the excretion of supersaturated Ca2+ and decreased the production of Ox, BUN in SD rat urine, and mitigated renal tissue damage by regulating Nrf2/HO-1 signaling pathway. Importantly, the three major compounds identified as active components of IDW contributed to the inhibition of CaOx nephrolithiasis formation. Overall, IDW holds significant potential for treating CaOx nephrolithiasis.

Dose-dependant preventive effect of a herbal compound on crystal formation in rat model.

INTRODUCTION: To analyze the dose-dependent preventive effect of a plant-based herbal product on the new crystal formation in a rat model. MATERIALS AND METHODS: A total of 42 rats were divided into 7 groups and zinc discs were placed into the bladder of rats to provide a nidus for the development of new crystal formation: Group 1: control, Group 2: 0.75 percent ethylene glycol (EG); Group 3: 0.75 percent EG plus 0.051 ml of the compound; Group 4: 0.75 percent EG plus 0.179 ml of the compound; Group 5: 0.75 percent EG plus 0.217 ml of the compound; Group 6: 0.75 percent EG plus 0.255 ml of the compound; Group 7 0.75 percent EG plus 0.332 of the compound). The analysis and comparison focused on the disc weights, changes in urinary oxalate and calcium levels, urinary pH, and the histopathologic evaluation of the inflammatory changes in the bladder after 14 days. RESULTS: According to the evaluation of discs placed in the bladders of the animals, animals receiving the herbal compound on a dose-dependent basis showed a limited increase in the disc weights values after 14 days, despite a considerable increase in animals receiving EG alone (p = 0.001). Further evaluation of the increase in disc weights on a dose-dependent basis in different subgroups (from Groups 3 to 7) demonstrated that the limitation of crystal deposition began to be more prominent as the dose of herbal compound increased. This effect was more evident particularly in comparisons between group 7 and others, according to LSD multiple comparison tests (p = 0.001). As anticipated, there has been no discernible change in the weight of the discs in the control group. Although urinary calcium levels in animals of Groups 2, 6, and 7 were significantly higher than the other groups, we were not able to demonstrate a close correlation between urinary oxalate levels and the increasing dose levels. Even though mean urine pH levels were statistically considerably higher in Group 3, there was no statistically significant correlation between the oxalate and calcium levels between all groups, and no association was seen with the administration of herbal agents. The transitional epithelium between the three groups of animals' bladder samples did not exhibit any appreciable difference according to pathological analysis. CONCLUSIONS: In this animal model, the treatment of the compound was successful in lowering the amount of crystal deposition surrounding the zinc discs, most noticeably at a dosage of 0.332 ml, three times per day.

In vivo investigation of the inhibitory effect of Peganum harmala L. and its major alkaloids on ethylene glycol-induced urolithiasis in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Peganum harmala L. is a traditional medicinal plant used for centuries in folk medicine. It has a wide array of therapeutic attributes, which include hypoglycemic, sedative, anti-inflammatory, and antioxidant properties. The fruit decoction of this plant was claimed by Avicenna as traditional therapy for urolithiasis. Also, P. harmala seed showed a clinical reduction in kidney stone number and size in patients with urolithiasis. AIM OF THE STUDY: In light of the above-mentioned data, the anti-urolithiatic activities of the seed extracts and the major ß-carboline alkaloids of P. harmala were investigated. MATERIALS AND METHODS: Extraction, isolation, and characterization of the major alkaloids were performed using different chromatographic and spectral techniques. The in vivo anti-urolithiatic action was evaluated using ethylene glycol (EG)-induced urolithiasis in rats by studying their mitigating effects on the antioxidant machinery, serum toxicity markers (i.e. nitrogenous waste, such as blood urea nitrogen, uric acid, urea, and creatinine), minerals (such as Ca, Mg, P, and oxalate), kidney injury marker 1 (KIM-1), and urinary markers (i.e. urine pH and urine output). RESULTS: Two major alkaloids, harmine (P1) and harmalacidine HCl (P2), were isolated and in vivo evaluated alongside the different extracts. The results showed that P. harmala and its constituents/fractions significantly reduced oxidative stress at 50 mg/kg body weight, p.o., as demonstrated by increased levels of glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), and catalase (CAT) in kidney homogenate as compared to the EG-treated group. Likewise, the total extract, pet. ether fraction, n-butanol fraction, and P1, P2 alleviated malondialdehyde (MDA) as compared to the EG-treated group. Serum toxicity markers like blood urea nitrogen (BUN), creatinine, uric acid, urea, kidney injury molecule-1 (Kim-1), calcium, magnesium, phosphate, and oxalate levels were decreased by total extract, pet. ether fraction, n-butanol fraction, P1, and P2 as compared to the EG-treated group. Inflammatory markers like NFκ-B and TNF-α were also downregulated in the kidney homogenate of treatment groups as compared to the EG-treated group. Moreover, urine output and urine pH were significantly increased in treatment groups as compared to the EG-treated group deciphering anti-urolithiatic property of P. harmala. Histopathological assessment by different staining patterns also supported the previous findings and indicated that treatment with P. harmala caused a gradual recovery in damaged glomeruli, medulla, interstitial spaces and tubules, and brown calculi materials as compared to the EG-treated group. CONCLUSION: The current research represents scientific evidence on the use of P. harmala and its major alkaloids as an effective therapy in the prevention and management of urolithiasis.

What treatments reduce kidney stone risk in patients with bowel disease?

We examined how physicians made therapeutic choices to decrease stone risk in patients with bowel disease without colon resection, many of whom have enteric hyperoxaluria (EH), at a single clinic. We analyzed clinic records and 24-h urine collections before and after the first clinic visit, among 100 stone formers with bowel disease. We used multivariate linear regression and t tests to compare effects of fluid intake, alkali supplementation, and oxalate-focused interventions on urine characteristics. Patients advised to increase fluid intake had lower initial urine volumes (L/day; 1.3 ± 0.5 vs. 1.7 ± 0.7) and increased volume more than those not so advised (0.7 ± 0.6 vs. 0.3 ± 0.6 p = 0.03; intervention vs. non-intervention). Calcium oxalate supersaturation (CaOx SS) fell (95% CI -4.3 to -0.8). Alkali supplementation increased urine pH (0.34 ± 0.53 vs. 0.22 ± 0.55, p = 0.26) and urine citrate (mg/d; 83 ± 256 vs. 98 ± 166, p = 0.74). Patients advised to reduce oxalate (mg/day) absorption had higher urine oxalate at baseline (88 ± 44 vs. 50 ± 26) which was unchanged on follow-up (88 (baseline) vs. 91 (follow-up), p = 0.90). Neither alkali (95% CI -1.4 to 2.1) nor oxalate-focused advice (95% CI -1.2 to 2.3) lowered CaOx SS. Physicians chose treatments based on baseline urine characteristics. Advice to increase fluid intake increased urine volume and decreased CaOx SS. Alkali and oxalate interventions were ineffective.

Investigation of the potential anti-urolithiatic activity of Alhagi maurorum (Boiss.) grown wild in Al-Ahsa (Eastern Province), Saudi Arabia.

The potential of Alhagi maurorum (Boiss.) aqueous extract (AME), used in traditional medicine for treatment or prevention of urolithiasis, to dissolve calcium oxalate stones in vitro was evaluated. In order to determine the litholytic potential of the extract, Calcium oxalate urinary stones were incubated during 12 weeks under continuous shaking in the presence of AME, Rowanix or NaCl 9 g/mL solution were used as controls. After the incubation period, the residual weight of the treated calculi was determined and the rate of dissolution was calculated. The medium pH variation was measured and changes in the calcium oxalate crystals at the stone surface were assessed using a scanning electron microscope (SEM). The results showed a significant dissolution effect for the extract on the kidney calculi during the experimentation period. At the end of the experiment, the percentages of calculi weight decrease were 41.23, 4.97 and 55.67% for the extract, NaCl solution and Rowanix, respectively. Gas Chromatography analysis revealed mainly the presence of the following phyto-compounds: Cyclopropenone, 2,3-diphenyl; 1-Nonadecanol; methyl-alpha-D-mannopyranoside; cis-9-Hexadecenal. These compounds unarguably play crucial roles in the health care system especially in cancer treatment and many other diseases including urolithiasis. The urinary stone dissolution, independent of medium pH, could be attributed to formation of complexes between the phytochemical compounds in the extract and the calculi.

Antiurolithiatic Potential of Three Sri Lankan Medicinal Plants by the Inhibition of Nucleation, Growth, and Aggregation of Calcium Oxalate Crystals In Vitro.

Background: Deposition and formation of stones in any part of the urinary system is called urolithiasis. CaOx is the predominant component of most stones, and the formation of these stones is a multistep process that includes supersaturation, nucleation, aggregation, growth, and retention. In ayurvedic medicine, medicinal plants are used for the management of kidney stones. The objective of this study was to determine the effect of aqueous, ethanol, and hexane extracts of Drymoglossum piloselloides leaves, Kalanchoe laciniata leaves, and Aegle marmelos flowers against CaOx urolithiasis in vitro. Methods: The crystallization of CaOx monohydrate (COM) and dihydrate (COD) was induced in a synthetic urine system. The nucleation, growth, and aggregation of crystals were measured using spectrophotometric methods. The results were compared against the polyherbal drug, Cystone, under identical concentrations. Crystals generated in the urine were also observed under light microscopy. Statistical differences and percentage inhibitions were calculated using standard formulae and compared. A preliminary phytochemical screening was also performed to detect active phytoconstituents present in the three plants used in the study. Results: The results obtained clearly demonstrated that Kalanchoe laciniata, Aegle marmelos, and Drymoglossum piloselloides have the capacity to inhibit the nucleation, growth, and aggregation of CaOx crystals. Microscopic examination of crystals revealed the presence of more COM than COD crystals but a dose-dependent reduction in crystals was observed in the presence of plant extracts. Hexane, ethanol, and aqueous extracts of all three plants had different capabilities to inhibit nucleation, growth, and aggregation of CaOx crystals but their activities were different at different concentrations. Preliminary phytochemical screening revealed the presence of reducing sugars, proteins, flavonoids, tannins, and polyphenol compound in Kalanchoe laciniata and Drymoglossum piloselloides and reducing sugars, proteins, anthracene glycosides, and saponins in Aegle marmelos. Conclusions: This study provided evidence that Kalanchoe laciniata, Aegle marmelos, and Drymoglossum piloselloides have the potential to be developed as inhibitors of nucleation, growth, and aggregation of CaOx crystals in the treatment of urolithiasis.

Calcium Citrate Versus Calcium Carbonate in the Management of Chronic Hypoparathyroidism: A Randomized, Double-Blind, Crossover Clinical Trial.

In hypoparathyroidism (HypoPT), calcium supplementation is virtually always required, although the disease is likely to be associated with an increased risk of nephrolithiasis. The use of calcium citrate (Ca-Cit) theoretically could have a positive impact on the nephrolithiasis risk because citrate salts are used to reduce this risk. Our objective was to evaluate the potential therapeutic advantage of Ca-Cit in comparison with calcium carbonate (CaCO3 ) in HypoPT, on nephrolithiasis risk factors, as well as to their ability to maintain desirable serum calcium levels. We also evaluated these preparations on quality of life (QOL). This randomized, double-blind, crossover trial recruited 24 adults with postsurgical chronic hypoparathyroidism at Campus Bio-Medico University of Rome. Participants were randomized 1:1 to Ca-Cit or CaCO3 for 1 month and then crossed over to the other treatment for another month. The primary outcomes were changes in albumin-adjusted serum calcium and in ion activity product of calcium oxalate levels (AP[CaOx] index). Secondary efficacy outcomes included changes in SF-36 survey score, fatigue score, constipation, and adverse events. No difference in terms of AP(CaOx) index was observed between the two groups. However, Ca-Cit was associated with a significant reduction in the oxalate/creatinine ratio compared with CaCO3 (-2.46 mmol/mol [SD 11.93] versus 7.42 mmol/mol [SD 17.63], p = 0.029). Serum calcium and phosphorus concentration was not different between the two calcium preparations. Ca-Cit was associated with less constipation (p = 0.047). No difference was found in QOL scores. Although Ca-Cit did not modify the AP(CaOx) index when compared with CaCO3, it was associated with a reduction in urinary oxalate excretion that could have a potential beneficial effect on nephrolithiasis risk. These results are likely to have clinical implications in HypoPT, particularly those who do not tolerate CaCO3 and those affected by nephrolithiasis. A longer-term experience is needed to confirm these findings. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Combined effect of polyacrylic acid and vitamin E in preventing calcium oxalate crystal deposition in the kidneys of experimental hyperoxaluric rats.

Our study explores the combined effect of polyacrylic acid and vitamin E as prophylactic and curative agent against ethylene glycol (EG) induced calcium oxalate stone formation in Wistar rats. Male Wistar rats (54) were divided into nine groups, including control. The experimental groups were equally segregated into two for preventive study (4) and curative study (4). Urolithiasis was induced with 0.75% (v/v) EG in drinking water. Polyacrylic acid (10 mg/kg) and vitamin E (300 IU/day) were supplemented from day 1 for preventive and day 30 for curative studies. Restoration of urinary lithogenic factors (calcium, oxalate, phosphate, citrate and magnesium) and renal function (urea and creatinine in serum) by intervening agents were accomplished compared to urolithic rats (P < .001). Abnormal localization and increased expression of Tamm-Horsfall Protein, osteopontin and transferrin were observed in the kidneys of urolithic rats (P < .001) from immunohistochemistry and immunoblotting analysis. Polyacrylic acid and vitamin E supplementation have regulated the expression of the urinary macromolecules. Pro-inflammatory cytokines in kidney were significantly reduced (P < .001) by the intervening agents compared to urolithic rats. Therefore, polyacrylic acid and vitamin E in combination could be a potential formulation for better management of urolithiasis.

Discovering inhibitor molecules for pathological crystallization of CaOx kidney stones from natural extracts of medical herbs.

ETHNOPHARMACOLOGICAL RELEVANCE: Kidney stones is one of the common diseases of the urinary system. The primary cause of kidney stone formation is the thermodynamic supersaturation of lithogenic solutes in urine, which desaturates by nucleation, crystal growth and aggregation of minerals and salts, mainly Calcium oxalate (CaOx). One of the potential therapies is to develop drug molecules to inhibit or prevent CaOx crystallization in urine. Traditional Chinese medicines (TCMs) provided an efficient approach for the treatment of kidney stones with a specialized-designed recipe of medicinal herbs. But the action details of these herbs were poorly understood due to their complex components, and whether the effective constituents of herbs have an inhibitory effect on the process of stone formation has not been evaluated. AIM OF THE STUDY: This study aims to develop and identify inhibitor substitutes from a library of kidney stone prescriptions in traditional Chinese medicines to prevent pathological kidney stone formation. MATERIALS AND METHODS: As many as twenty Chinese medicines were extracted and separated into five different polar extracts, the inhibition performance of which on CaOx crystallization was explored by recording and comparing crystallization kinetics. The potential inhibitor molecules in the inhibitory extracts were confirmed by HPLC and their retardation efficacy was evaluated by quantifying nucleation and growth kinetics using colorimetry. Then the inhibitor-COM crystal interactions and specificity were examined by morphology evolution and surface structure analysis. In vitro inhibition performance of inhibitors on crystal growth and attachment of CaOx crystals to human renal epithelial cells were further evaluated by recording the nucleation and adhesive crystal numbers. RESULTS AND CONCLUSION: Water- and n-butanol- soluble extracts from 20 kinds of herbs show almost 100% inhibition percentage, and the n-butanol extracts was found better than commercial drug citrate. Twenty-one molecule substitutes were identified from these extracts, and among them polyphenols display the best inhibition efficacy to retard CaOx crystallization. The high-throughput colorimetric assay and morphology examinations reveals thirteen out of 21 molecules show inhibition potential and disrupt growth of CaOx monohydrate crystals by interacting with exposed Ca2+ and C2O42- on the (100) and (010) surfaces. Moreover, these inhibitors also display pronounced performance in protecting renal epithelial cells by inhibiting nucleation and adhesion of CaOx crystals to cells, thus reducing stone formation. The structure-performance correlation among 19 screened molecules that inhibitors having pKa<3.5, logD (pH = 6) <0, H-number>0.1 mmol are the best in suppressing CaOx crystallization. Our findings provide a novel solution to design and manufacture inhibitor drugs from Chinese medicines for preventing pathological kidney stones formation.

Evaluations of the curative efficacy of G. fruticosus solvent extracts in experimentally induced nephrolithiatic Wistar male rats.

BACKGROUND: In Ethiopian folk medicine, there is a claim that medicinal plants can treat urolithiasis although there is insufficient scientific evidence. The objective of this study was to evaluate the curative efficacy of Gomphocarpus fruticosus extracts in experimentally induced nephrolithiatic rats. METHODS: Urolithiasis was induced in male Wistar rats by feeding ethylene glycol in drinking water for 28 days. The curative effects were evaluated after oral administrations of 200 mg/kg of the extracts from 15 to 28 days. Urine samples were collected 1 day before sacrificing the rats. Blood, liver and kidney samples were gathered under anaesthetic condition at day 28. Crystals in the urine were also analyzed by light microscopy. RESULTS: G. fruticosus EtOAc extract reduced significantly the level of sodium (P < 0.001), whereas it was significantly elevated the levels of magnesium and citrate (P < 0.01) compared to lithiatic control. G. fruticosus BuOH extract lowered the levels of potassium (P < 0.01), calcium and phosphate in urolithiatic rats. It was also observed that G. fruticosus EtOAc extract decreased the level of oxalate in the urine (P < 0.001), whereas it was increased the levels of magnesium (P < 0.05) and citrate (P < 0.01) in serum analysis after exposure to BuOH extract. In the kidneys, CaOx crystal deposits were reduced significantly by G. fruticosus EtOAc extract (P < 0.01). CONCLUSION: It has been noted that G. fruticosus EtOAc extract was potent in treating urolithiasis. However, further study is required to assess the efficacy of the active compounds against urolithiasis.

Antiurolithic effects of medicinal plants: results of in vivo studies in rat models of calcium oxalate nephrolithiasis-a systematic review.

Urolithiasis is one of the oldest diseases affecting humans, while plants are one of our oldest companions providing food, shelter, and medicine. In spite of substantial progress in understanding the pathophysiological mechanisms, treatment options are still limited, often expensive for common people in most parts of the world. As a result, there is a great interest in herbal remedies for the treatment of urinary stone disease as an alternative or adjunct therapy. Numerous in vivo and in vitro studies have been carried out to understand the efficacy of herbs in reducing stone formation. We adopted PRISMA guidelines and systematically reviewed PubMed/Medline for the literature, reporting results of various herbal products on in vivo models of nephrolithiasis/urolithiasis. The Medical Subject Heading Terms (Mesh term) "Urolithiasis" was used with Boolean operator "AND" and other related Mesh Unique terms to search all the available records (July 2019). A total of 163 original articles on in vivo experiments were retrieved from PubMed indexed with the (MeshTerm) "Urolithiasis" AND "Complementary Therapies/Alternative Medicine, "Urolithiasis" AND "Plant Extracts" and "Urolithiasis" AND "Traditional Medicine". Most of the studies used ethylene glycol (EG) to induce hyperoxaluria and nephrolithiasis in rats. A variety of extraction methods including aqueous, alcoholic, hydro-alcoholic of various plant parts ranging from root bark to fruits and seeds, or a combination thereof, were utilized. All the investigations did not study all aspects of nephrolithiasis making it difficult to compare the efficacy of various treatments. Changes in the lithogenic factors and a reduction in calcium oxalate (CaOx) crystal deposition in the kidneys were, however, considered favorable outcomes of the various treatments. Less than 10% of the studies examined antioxidant and diuretic activities of the herbal treatments and concluded that their antiurolithic activities were a result of antioxidant, anti-inflammatory, and/or diuretic effects of the treatments.

The Efficacy of Polyunsaturated Fatty Acids as Protectors against Calcium Oxalate Renal Stone Formation: A Review.

In the pathogenesis of hypercalciuria and hyperoxaluria, n-6 polyunsaturated fatty acids (PUFAs) have been implicated by virtue of their metabolic links with arachidonic acid (AA) and prostaglandin PGE2. Studies have also shown that n-3 PUFAs, particularly those in fish oil-eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)-can serve as competitive substrates for AA in the n-6 series and can be incorporated into cell membrane phospholipids in the latter's place, thereby reducing urinary excretions of calcium and oxalate. The present review interrogates several different types of study which address the question of the potential roles played by dietary PUFAs in modulating stone formation. Included among these are human trials that have investigated the effects of dietary PUFA interventions. We identified 16 such trials. Besides fish oil (EPA+DHA), other supplements such as evening primrose oil containing n-6 FAs linoleic acid (LA) and γ-linolenic acid (GLA) were tested. Urinary excretion of calcium or oxalate or both decreased in most trials. However, these decreases were most prominent in the fish oil trials. We recommend the administration of fish oil containing EPA and DHA in the management of calcium oxalate urolithiasis.

Amelioration of hyperoxaluria-induced kidney dysfunction by chemical chaperone 4-phenylbutyric acid.

Hyperoxaluria is characterized by an increased excretion of urinary oxalate which is caused by inherited disorders or high oxalate intake leading to renal stone ailment. Until date, reactive oxygen species and inflammation has been convicted for the progression of kidney stones for which antioxidant therapy has been employed. However, recent studies have linked the association of endoplasmic reticulum stress and oxidative imbalance in the progression of renal diseases. Considering oxidative stress being at forefront in causing hyperoxaluric consequences, current study was designed to correlate the impact of hyperoxaluria and regulation of oxidative imbalance via inhibition of endoplasmic reticulum stress by 4-phenylbutyric acid (4-PBA). Male wistar rats were subdivided into three groups, i.e., normal control (C), hyperoxaluric rats given ethylene glycol (EG), and hyperoxaluric rats treated with 4-PBA (EG + PBA). After 28 days of treatment, assessment of antioxidant defence system, inflammation, ER stress, and subsequent unfolded protein response was studied in renal tissue. It was found that the hyperoxaluric insult led to a marked damage to the renal tissue resulting in compromised antioxidant levels, upregulation of ER stress markers along with a steep surge in the extent of inflammation. However, 4-PBA treatment significantly curtailed the deleterious effects of hyperoxaluria by lowering down the level of stress markers as well as normalizing the antioxidant defence enzymes. Therefore, chemical chaperones can be deemed as a new class of drugs for the treatment of hyperoxaluric induced renal damage.

Protective potential of Angelica sinensis polysaccharide extract against ethylene glycol-induced calcium oxalate urolithiasis.

PURPOSE: To evaluate a Angelica sinensis polysaccharide aqueous extract as a preventive agent in experimentally induced urolithiasis using in- vitro and vivo models. MATERIAL AND METHODS: Angelica sinensis polysaccharide was investigated in vitro to determine its antilithiatic effects on the formation and morphology of calcium oxalate (CaOx) crystals and was analyzed in vivo to determine its ability to prevent CaOx urolithiasis in rats subjected to ethylene glycol-induced urolithiasis. Potassium citrate administration was used in the positive control group. The urolithiasis-related biochemical parameters were evaluated in the rats urine, serum and kidney homogenates. Kidney sections were subjected to histopathological and immunohistochemical analyses, and urolithiasis-related phospho-c-Jun NH2-terminal protein kinase and kidney injury molecule-1proteins were evaluated by Western blot analyses. RESULTS: Angelica sinensis polysaccharide exhibited concentration-dependent inhibition of CaOx crystal formation. The in vitro assay revealed significant inhibition of crystal formation (6.99 ± 1.07) in the group treated with 4.0 mg/mL Angelica sinensis polysaccharide extract compared with the control group (58.38 ± 5.63; p < .05). In vivo, after treatment with ethylene glycol for 28 days, urinary oxidative stress, oxalate, creatinine, urea and urolithiasis-related protein were significantly increased (p < .05), except for serum oxidative stress (p > .05). The rats administered the extract of Angelica sinensis polysaccharide showed significantly decreased pathological change and CaOx deposition (p < .05) compared with the urolithiatic rats. Significantly reduced levels of urinary oxidative stress, oxalate, creatinine, urea and urolithiasis-related protein were observed in the Angelica sinensis polysaccharide treatment groups (p < .05) compared with the nephrolithic rats. CONCLUSION: The results presented here suggest that Angelica sinensis polysaccharide has the potential to inhibit CaOx crystallization in vitro and may present anti-urolithiatic effects in vivo.

Lime powder treatment reduces urinary excretion of total protein and transferrin but increases uromodulin excretion in patients with urolithiasis.

Our previous study has shown that lime powder (LP) had an inhibitory effect against calcium oxalate stone formation. However, the precise mechanisms underlying such beneficial effect remained unclear. Our present study thus aimed to address the effect of LP on excretory level and compositions of urinary proteins using a proteomics approach. From a total of 80 calcium oxalate stone formers recruited into our 2-year randomized clinical trial of LP effect, 10 patients with comparable age and clinical parameters were selected for this proteomic study. 24-h urine specimens were collected from all subjects, at baseline (before) and after LP treatment for 6 months, and then subjected to quantitative proteomics analysis and subsequent validation by ELISA. Total urinary protein excretion was significantly decreased by LP treatment, but unaffected by placebo. Nanoflow liquid chromatography coupled to tandem mass spectrometry (nanoLC-MS/MS) followed by quantitative analysis revealed 17 proteins whose levels were significantly altered (16 decreased and 1 increased) exclusively by LP treatment. Among these, the decrease of transferrin and increase of uromodulin were validated by ELISA. Moreover, there was a significant correlation between microalbuminuria and urinary transferrin level by Pearson's correlation test. In summary, LP treatment caused significant reduction in total urinary protein excretion and changes in urinary protein compositions that could be linked to stone inhibitory effects and might be relevant mechanisms responsible for the beneficial effects of LP to prevent kidney stone formation and recurrence.

Total flavonoids of Desmodium styracifolium attenuates the formation of hydroxy-L-proline-induced calcium oxalate urolithiasis in rats.

Desmosium styracifolium (D. styracifolium), which is considered as a Chinese herbal medicine, has been reported to treat the kidney stone diseases. However, the potential phytochemically active components and the underlying mechanisms associated with its efficacy in targeting urolithiasis remain to be elucidated. This study aims to investigate the anti-urolithiatic effect of total flavonoids of D. styracifolium (TFDS) on calcium oxalate (CaOx) renal stones in Sprague-Dawley rats. Animal models of CaOx urolithiasis were established in male Sprague-Dawley rats by adding 5% w/w hydroxy-L-proline (HLP) in regular rat chow. The TFDS orally at 100, 400 mg/kg, respectively, were administered along with HLP for 28 days. At the end of 28 days of treatment, urine and serum samples were collected for crystalluria determination and various biochemical analysis. Kidney tissues were isolated and processed for antioxidant parameters measurement and histopathological examinations. HLP-induced hyperoxaluria alone reliably caused CaOx nephrolithiasis in rats. We showed that TFDS significantly reduced crystalluria and CaOx crystal deposits in the kidney sections as compared to untreated HLP group. Also, TFDS was observed to decrease urinary oxalate excretion, alleviate the pro-acidosis condition, improve the impaired renal functions and renal epithelial cell injury. Moreover, TFDS protected against the oxidative stress changes via reducing MDA content, increasing CAT and GSH-Px activities in renal homogenate, as well as attenuating the expression of MCP-1, OPN and TGF-ß proteins. These results indicated that TFDS had beneficial effect on inhibition of CaOx formation in the rat kidney probably through a combination of antioxidant, anti-inflammatory, urine alkalinizing activities, and lowering the concentration of urinary stone-forming constituents. Thus, TFDS might have clinical implications in preventing oxidative renal cell injury and, ultimately, kidney stone formation. The data provide a rationale for the medicinal use of TFDS in nephrolithiasis and identify this agent as a potential source of new antiurolithic drugs.

Role of gut microbiota against calcium oxalate.

Nephrolithiasis is a condition marked by the presence or formation of stones in kidneys. Several factors contribute to kidney stones development such as environmental conditions, type of dietary intake, gender and gastrointestinal flora. Most of the kidney stones are composed of calcium phosphate and calcium oxalate, which enter in to the body through diet. Both sources of oxalates become dangerous when normal flora of gastrointestinal tract is disturbed. Oxalobacter and Lactobacillus species exist symbiotically in the human gut and prevent stone formation by altering some biochemical pathways through production of specific enzymes which help in the degradation of oxalate salts. Both Oxalobacter and Lactobacillus have potential probiotic characteristics for the prevention of kidney stone formation and this avenue should be further explored.

Hyperoxaluria in a Model of Mini-Gastric Bypass Surgery in Rats.

BACKGROUND: Bariatric surgery is associated with hyperoxaluria hence predisposing to nephrolithiasis. The present study aimed to investigate the underlying mechanisms contributing to increased urinary oxalate in a mini-gastric bypass (MGB) surgery model in rats under different dietary conditions. The expression of intestinal oxalate transporters was also evaluated. METHODS: Male rats underwent MGB (n = 21) or Sham procedure (n = 21) and after recovery were fed a standard or high-fat diet with or without oxalate for 8 weeks. Stool and urine were collected before surgery (baseline) and at the end of protocol (final), when intestinal fragments were harvested for expression of Slc26a3 and Slc26a6 oxalate transporters. RESULTS: MGB groups fed with fat, irrespective of oxalate supplementation, presented steatorrhea. In MGB animals fed with fat and oxalate (Fat + Ox), final values of urinary oxalate and calcium oxalate supersaturation risk were markedly and significantly increased versus baseline or Sham animals under the same diet, as well as MGB groups under other diets. Slc26a3 was decreased in biliopancreatic limbs of MGB rats, probably reflecting a physiological adaptation to the restriction of food passage. Slc26a6 was not altered in any harvested intestinal fragment. CONCLUSIONS: A high-fat and oxalate diet induced hyperoxaluria and elevation in calcium oxalate supersaturation risk in a MGB rat model. The presence of fat malabsorption and increased dietary oxalate absorption, but not modifications of Slc26a3 and Slc26a6 oxalate transporters, accounted for these findings, suggesting that bariatric patients may benefit from a low-fat and low-oxalate diet.

Inhibitory effect of an aqueous extract of Radix Paeoniae Alba on calcium oxalate nephrolithiasis in a rat model.

OBJECTIVE: To examine the effect of an aqueous extract of Radix Paeoniae Alba (RPA) on the formation of calcium oxalate (CaOx) stones and the potential mechanism underlying the effect. MATERIALS AND METHODS: An in vitro assay was used to determine whether the RPA extract prevents the formation of CaOx or promotes CaOx dissolution. We also investigated the efficacy of the extract in vivo as a preventive and therapeutic agent for experimentally induced CaOx nephrolithiasis in rats. Various biochemical, molecular, and histological parameters were assessed in kidney tissue and urine at the end of the in vivo experiment. RESULTS: Significant dissolution of formed crystals (8.99 ± 1.43) and inhibition of crystal formation (2.55 ± 0.21) were observed in vitro after treatment with 64 mg/mL of the RPA extract compared with a control treatment (55.10 ± 4.98 and 54.57 ± 5.84, respectively) (p < .05). In preventive protocols, the RPA extract significantly reduced urinary and renal oxalate levels and increased urinary calcium and citrate levels compared to the control. In addition, the RPA preventive protocol significantly decreased osteopontin expression, renal crystallization, and pathological changes compared to the control. These changes were not observed in rats on the therapeutic protocol. CONCLUSIONS: RPA is a useful agent that prevents the formation of CaOx kidney stones.