Preventive Effect of Specific Antioxidant on Oxidative Renal Cell Injury Associated With Renal Crystal Formation

Fishman, Andrew I.; Green, David; Lynch, Alexandria; Choudhury, Muhammad; Eshghi, Majid; Konno, Sensuke

doi:10.1016/j.urology.2013.03.065

Cited by 20 publications

(17 citation statements)

References 23 publications

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“…Fishman et al. have shown that ascorbic acid is virtually ineffective at preventing COM crystal‐induced oxidative injury in cultured renal epithelial cells, which differ from our present findings. When we repeated the same experiments in vitro using LLC‐PK1 cells (200 μ m of ascorbic acid and 200 μg/mL COM crystals, 24‐h exposure), and measured LDH activity in the medium as a marker of cell injury, we found that ascorbic acid significantly prevented COM‐induced cell injury.…”

Section: Discussioncontrasting

confidence: 99%

“…Moreover, the combined treatment of α‐tocopherol and ascorbic acid to oxalate‐exposed LLC‐PK1 cells resulted in remarkable protection against toxicity. Most recently, without adequate explanation, the results of a study that examined the in vitro and in vivo effects of ascorbic acid on hyperoxaluria‐induced cell injury have been reported . Fishman et al.…”

Section: Discussionmentioning

confidence: 99%

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Oxalate at physiological urine concentrations induces oxidative injury in renal epithelial cells: effect of α‐tocopherol and ascorbic acid

2014

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ObjectivesTo test our hypothesis that physiological levels of urinary oxalate induce oxidative renal cell injury, as studies to date have shown that oxalate causes oxidative injury only at supra-physiological levels. To study the combined effect of α-tocopherol and ascorbic acid against oxalate-induced oxidative injury, as oxalate-induced oxidative cell injury is known to promote initial attachment of calcium oxalate crystals to injured renal tubules and subsequent development of kidney stones. Materials and MethodsCultures of normal (antioxidant-undepleted) and antioxidant-depleted LLC-PK1 cells were exposed to oxalate at human physiological urine concentrations. After exposure, markers of oxidative stress and cell injury were measured in the cells and media, respectively. In addition, we also evaluated the combined effects of α-tocopherol and ascorbic acid on oxalate-induced oxidative cell injury. ResultsExposure of renal cells to oxalate at urinary physiological levels increased the oxidative cell injury as assessed by increased lactate dehydrogenase (LDH) leakage and increased lipid hydroperoxide in the renal cells; however, this effect was not seen until 24 h after oxalate exposure, at which point the injury was milder. On the other hand, when cellular reduced glutathione (GSH) and catalase were depleted in renal epithelial cells with pharmacological inhibitors, the physiological levels of urinary oxalate caused significant oxidative cell injury at 24 h, and remarkably, when additional endogenous antioxidants were depleted, the oxalate at the upper limit of normal 24 h urine caused a significant amount of cell injury in a shorter period of time, which was comparable to that seen in cells exposed to higher levels of oxalate. Exposure of LLC-PK1 cells to oxalate resulted in increased levels of H2O2 and lipid hydroperoxide, correlating with increased release of cell injury markers, including LDH, alkaline phosphate, and γ-glutamyl transpeptidase from renal tubular epithelial cells. Oxalate exposure decreased the activity and protein expression of superoxide dismutase and glutathione peroxidase in a time-dependent manner. LLC-PK1 cells treated with oxalate and either α-tocopherol or ascorbic acid alone exhibited a significant decrease in oxidative cell injury and restored endogenous renal antioxidants towards normal levels, and interestingly, combined treatment with α-tocopherol and ascorbic was more efficient at preventing oxalate-induced toxicity than treatment with either agent alone. ConclusionTo our knowledge this is the first study to show that oxalate alone at human physiological urine concentrations (in the absence of calcium oxalate crystal formation), induced oxidative renal injury in renal epithelial cells when endogenous antioxidants are depleted. Our data further suggests that a combination of α-tocopherol and ascorbic acid may be more effective than each individual agent in reducing oxalate-induced oxidative renal injury and subsequent calcium oxalate crystal deposition in recurrent stone formers.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Oxalate at physiological urine concentrations induces oxidative injury in renal epithelial cells: effect of α‐tocopherol and ascorbic acid

2014

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“…Oxalate is an end product of metabolism, and a high level of oxalate can lead to hyperoxaluria and even in the formation of caOx-induced kidney stones (24). In this study, it was found that oxalate at various concentrations led to a decrease in the viability of human renal tubular epithelial cells, and such a result was consistent with the findings of previous studies (25,26). A previous study reported that miR-30c alleviated diabetic nephropathy via the Snail1/TGF-β1 pathway (27).…”

Section: Discussionsupporting

confidence: 92%

Overexpression of miR‑30c‑5p reduces cellular cytotoxicity and inhibits the formation of kidney stones through ATG5

et al. 2019

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MicroRNAs (miRNAs or miRs) are critical regulators in various diseases. In the current study, the role of miR-30c-5p in the formation of sodium oxalate-induced kidney stones was investigated. For this purpose, human renal tubular epithelial cells (HK-2 cells) were incubated with sodium oxalate at the concentrations of 100, 250, 500, 750 and 1,000 µM. cell viability and the miR-30c-5p expression level were respectively measured by ccK-8 assay and RT-qPcR. After separately transfecting miR-30c-5p mimic and inhibitor into the HK-2 cells, the cell apoptotic rate, the levels of mitochondrial membrane potential (MMP) and ROS were determined by flow cytometry. The levels of oxidative stress indicators [lactate dehydrogenase (LdH), malondialdehyde (MdA), superoxide dismutase (SOd) and catalase (cAT)] were determined using commercial kits. crystal-cell adhesion assay was performed to evaluate the crystal adhesion capacity in vitro. miR-30c-5p binding at autophagy related 5 (ATG5) was predicted by TargetScan7.2 and further verified by dual-luciferase reporter assay. Rescue experiments were performed to confirm the molecular mechanisms underlying sodium oxalate-induced kidney formation in HK-2 cells. The results revealed that sodium oxalate decreased the viability of HK-2 cells in a concentration-dependent manner, and that miR-30c-5p expression was significantly downregulated by exposure to 750 µM sodium oxalate. In addition, the increase in cell apoptosis and crystal number, and the upregulated levels of LdH, MdA and ROS were reversed by the overexpression of miR-30c-5p. Moreover, the overexpression of miR-30c-5p upregulated the levels of SOd, cAT and MMP induced by sodium oxalate. ATG5 was directly regulated by miR-30c-5p, and the inhibition of cell cytotoxicity and crystal-cell adhesion induced by miR-30c-5p mimic was blocked by ATG5. These data indicated that the overexpression of miR-30c-5p alleviated cell cytotoxicity and crystal-cell adhesion induced by sodium oxalate through ATG5. Thus, the current study provides a better understanding of the role of miR-30c-5p in sodium oxalate-induced kidney stones.

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“…In fact, antioxidant enzymes such as catalase and superoxide dismutase and chemical (non-enzymatic) antioxidant, vitamin E, have been shown to effectively reduce oxidative stress, resulting in decreased renal cell injury and crystal deposition in the kidneys [11]. Our previous study also demonstrated that a potent antioxidant, N-acetylcysteine (NAC), was capable of significantly (> 70%) preventing and reducing chemically induced CaOx crystal formation in rats [12]. …”

Section: Introductionmentioning

confidence: 99%

Antioxidant and Renoprotective Effects of Mushroom Extract: Implication in Prevention of Nephrolithiasis

et al. 2016

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BackgroundThe pathogenesis of nephrolithiasis (kidney stone) remains elusive, while several therapeutic options are available but not effective as we expected. Accumulating data yet suggest that oxidative stress (generation of oxygen free radicals) may play a primary role in its occurrence. Particularly, calcium oxalate (CaOx) is a key element in the most common form (> 75%) of kidney stones, and its crystal form known as CaOx monohydrate (COM) has been shown to exert oxidative stress, facilitating CaOx stone formation. Hence, diminishing oxidative stress with certain antioxidants could be a potential strategic approach. We are interested in a bioactive extract of Poria mushroom, PE, which has been shown to have antioxidant and renoprotective activities. Accordingly, we investigated if PE might have antioxidant activity that would have implication in prevention of kidney stone formation.MethodsRenal epithelial LLC-PK1 cells were employed and exposed to COM or hydrogen peroxide (H2O2) as a positive control capable of exerting oxidative stress. Possible antioxidant and protective effects of PE against oxidative stress (exerted by COM or H2O2) were assessed by cell viability test and lipid peroxidation (LPO) assay. To explore its protective mechanism, two glycolytic parameters, hexokinase (HK) activity and ATP synthesis, were examined and cell cycle analysis was also performed.ResultsBoth H2O2 and COM led to a significant (P < 0.05) reduction in cell viability, accompanied by severe oxidative stress assessed by LPO assay. Such oxidative stress also caused the significant decline in HK activity and cellular ATP level, indicating the inhibition of glycolysis. Cell cycle analysis further indicated that oxidative stress interfered with cell cycle, inducing a G1 cell cycle arrest that presumably results in the cessation of cell proliferation. However, PE was capable of significantly preventing or diminishing all these cellular effects mediated through oxidative stress (exerted by H2O2 and COM).ConclusionsThe present study shows that the mushroom extract PE appears to have antioxidant and renoprotective effects against oxidative stress exerted by COM in renal cells. Therefore, PE with antioxidant activity is considered a promising natural agent that may have clinical implications in prevention of nephrolithiasis primarily induced by oxidative stress.

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Preventive Effect of Specific Antioxidant on Oxidative Renal Cell Injury Associated With Renal Crystal Formation

Cited by 20 publications

References 23 publications

Oxalate at physiological urine concentrations induces oxidative injury in renal epithelial cells: effect of α‐tocopherol and ascorbic acid

Oxalate at physiological urine concentrations induces oxidative injury in renal epithelial cells: effect of α‐tocopherol and ascorbic acid

Overexpression of miR‑30c‑5p reduces cellular cytotoxicity and inhibits the formation of kidney stones through ATG5

Antioxidant and Renoprotective Effects of Mushroom Extract: Implication in Prevention of Nephrolithiasis

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