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2058 PREVENTIVE EFFECT OF SPECIFIC ANTIOXIDANT ON OXIDATIVE RENAL CELL INJURY FACILITATING RENAL CRYSTAL FORMATION: IN VITRO AND IN VIVO STUDIES
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THE JOURNAL OF UROLOGY姞
Vol. 185, No. 4S, Supplement, Wednesday, May 18, 2011
2059 AQUEOUS EXTRACT OF COSTUS SPIRALIS ROSCOE INHIBITS CALCIUM OXALATE CRYSTAL GROWTH AND ADHESION TO RENAL EPITHELIAL CELLS Mitra R. de Co´ga´in*, Michael P. Linnes, Rochester, MN; Sung-Hoon Kim, Seoul, Korea, Republic of; John C. Lieske, Rochester, MN
Source of Funding: None
2058 PREVENTIVE EFFECT OF SPECIFIC ANTIOXIDANT ON OXIDATIVE RENAL CELL INJURY FACILITATING RENAL CRYSTAL FORMATION: IN VITRO AND IN VIVO STUDIES Andrew Fishman*, David Green, Alexandria Lynch, Muhammad Choudhury, Majid Eshghi, Sensuke Konno, Valhalla, NY INTRODUCTION AND OBJECTIVES: Calcium oxalate (CaOx), a major element for the most common form of kidney stones, has been shown to induce renal cell injury through oxidative stress, and its crystallization becoming CaOx monohydrate (COM) is a prerequisite for ultimate stone formation. It is yet possible that certain antioxidants may prevent such crystal formation by abolishing oxidative stress. We thus investigated if COM could exert oxidative stress on renal cells (in vitro) and if certain antioxidants might prevent renal crystal formation in the rats (in vivo). METHODS: Renal proximal tubular OK cells were employed as our in vitro model, while CaOx crystals were induced in the rats by the established chemical method using ethylene glycol (EG) and vitamin D3 (VD3). Oxidative stress on OK cells was assessed by lipid peroxidation assay and activity of detoxifying enzyme, glyoxalase I (Gly-I), was also determined. Two antioxidants, vitamin C (VC) and N-acetylcysteine (NAC), were examined if they could relieve oxidative stress in vitro and prevent crystal formation in vivo. Wistar rats were divided into 4 groups and received the following agents: Group 1 (Sham); Group 2 received EG/VD3; Group3 received EG/VD3 and NAC; and Group 4 received EG/VD3 and VC. All rats were sacrificed after 2 weeks and kidneys were harvested for histopathological examination and Gly-I activity. RESULTS: COM ⱖ500 g/ml induced a ⬎45% reduction in OK cell viability with a ⬃1.8-fold greater oxidative stress and a ⬃55% lower Gly-I activity than controls. However, such adverse events were almost completely prevented with NAC, not with VC. In the rat study, no renal crystals were seen in the Sham Group but numerous crystals, with reduced Gly-I activity, were found in the Groups 2 and 4. Yet, markedly (⬎70%) less crystals, with full Gly-I activity, were detected in the Group 3, indicating that NAC could effectively prevent crystal formation and Gly-I inactivation in the rats. CONCLUSIONS: Although COM indeed exerted oxidative stress on OK cells, inducing the cell viability reduction and Gly-I inactivation, NAC was capable of fully preventing such detrimental outcomes. Similarly, numerous crystal formation with Gly-I inactivation in the rats (Group 2) were significantly prevented with NAC supplement (Group 3). Taken together, oxidative stress appears to be a critical event, which may facilitate CaOx crystal formation, but could be entirely abolished with NAC. Thus, it is plausible that NAC may have clinical implications in preventing oxidative renal cell injury and ultimate kidney stone formation. Source of Funding: Research Grant from New York Academy of Medicine
INTRODUCTION AND OBJECTIVES: Costus spiralis Roscoe (C. spiralis) is a plant used in Brazilian folk medicine to treat urolithiasis; however, its’ mechanism(s) of action has yet to be elucidated. The interaction between calcium oxalate (CaOx) crystals and the renal epithelium appears important in calculogenesis, and compounds that modulate this process or other aspects of crystal formation represent candidate therapeutic agents for stone prevention. Therefore, we assessed the inhibitory activity of C. spiralis on CaOx crystallization and the interaction of CaOx crystals with the renal epithelium. METHODS: A seeded CaOx monohydrate (COM) crystallization system was used to study the effect of C. spiralis on crystal growth. Madin Darby canine kidney (MDCK) cells were used to study [14C] COM crystal adhesion in the presence and absence of an aqueous extract of C. spiralis. Cytotoxicity was assessed using a tetrazolium (MTS) cell proliferation assay. RESULTS: Aqueous C. spiralis extract decreased crystal growth in a concentration-dependent manner. The extract decreased crystal adhesion to MDCK cells in a concentration-dependent fashion (Fig. 1). Precoating crystals was effective, while pretreating cells had no effect. The extract was not cytotoxic in concentrations up to 1000 g/ml. No crystal growth or adhesion activity was found in hexane, methyl chloride, n-butanol, ethyl acetate or water fractions of an ethanol extract of the herb, suggesting that activity may reside in a polar compound. CONCLUSIONS: Our findings suggest that C. spiralis contains a compound(s) that may delay calculogenesis by interacting with CaOx crystal surfaces. As activity was present in an aqueous extract, this agent may be bioavailable when administered orally. Preliminary fractionization trials suggest that the active agent might be a polar compound such as a polysaccharide and further identification and characterization appears warranted.
Source of Funding: This work was supported by the Mayo Clinic O’Brien Urology Research Center P50 DK083007 and the Mayo Foundation.
2060 DIETARY OXALATE: WHAT’S IMPORTANT AND WHAT ISN’T FOR PATIENTS WITH CALCIUM OXALATE STONES? Kristina L. Penniston*, Katrina F. Wojciechowski, Stephen Y. Nakada, Madison, WI INTRODUCTION AND OBJECTIVES: Dietary oxalate may account for up to 50% of urinary oxalate in individuals with calcium oxalate urolithiasis. In patients with hyperoxaluria, reducing dietary
THE JOURNAL OF UROLOGY姞
Vol. 185, No. 4S, Supplement, Wednesday, May 18, 2011
2059 AQUEOUS EXTRACT OF COSTUS SPIRALIS ROSCOE INHIBITS CALCIUM OXALATE CRYSTAL GROWTH AND ADHESION TO RENAL EPITHELIAL CELLS Mitra R. de Co´ga´in*, Michael P. Linnes, Rochester, MN; Sung-Hoon Kim, Seoul, Korea, Republic of; John C. Lieske, Rochester, MN
Source of Funding: None
2058 PREVENTIVE EFFECT OF SPECIFIC ANTIOXIDANT ON OXIDATIVE RENAL CELL INJURY FACILITATING RENAL CRYSTAL FORMATION: IN VITRO AND IN VIVO STUDIES Andrew Fishman*, David Green, Alexandria Lynch, Muhammad Choudhury, Majid Eshghi, Sensuke Konno, Valhalla, NY INTRODUCTION AND OBJECTIVES: Calcium oxalate (CaOx), a major element for the most common form of kidney stones, has been shown to induce renal cell injury through oxidative stress, and its crystallization becoming CaOx monohydrate (COM) is a prerequisite for ultimate stone formation. It is yet possible that certain antioxidants may prevent such crystal formation by abolishing oxidative stress. We thus investigated if COM could exert oxidative stress on renal cells (in vitro) and if certain antioxidants might prevent renal crystal formation in the rats (in vivo). METHODS: Renal proximal tubular OK cells were employed as our in vitro model, while CaOx crystals were induced in the rats by the established chemical method using ethylene glycol (EG) and vitamin D3 (VD3). Oxidative stress on OK cells was assessed by lipid peroxidation assay and activity of detoxifying enzyme, glyoxalase I (Gly-I), was also determined. Two antioxidants, vitamin C (VC) and N-acetylcysteine (NAC), were examined if they could relieve oxidative stress in vitro and prevent crystal formation in vivo. Wistar rats were divided into 4 groups and received the following agents: Group 1 (Sham); Group 2 received EG/VD3; Group3 received EG/VD3 and NAC; and Group 4 received EG/VD3 and VC. All rats were sacrificed after 2 weeks and kidneys were harvested for histopathological examination and Gly-I activity. RESULTS: COM ⱖ500 g/ml induced a ⬎45% reduction in OK cell viability with a ⬃1.8-fold greater oxidative stress and a ⬃55% lower Gly-I activity than controls. However, such adverse events were almost completely prevented with NAC, not with VC. In the rat study, no renal crystals were seen in the Sham Group but numerous crystals, with reduced Gly-I activity, were found in the Groups 2 and 4. Yet, markedly (⬎70%) less crystals, with full Gly-I activity, were detected in the Group 3, indicating that NAC could effectively prevent crystal formation and Gly-I inactivation in the rats. CONCLUSIONS: Although COM indeed exerted oxidative stress on OK cells, inducing the cell viability reduction and Gly-I inactivation, NAC was capable of fully preventing such detrimental outcomes. Similarly, numerous crystal formation with Gly-I inactivation in the rats (Group 2) were significantly prevented with NAC supplement (Group 3). Taken together, oxidative stress appears to be a critical event, which may facilitate CaOx crystal formation, but could be entirely abolished with NAC. Thus, it is plausible that NAC may have clinical implications in preventing oxidative renal cell injury and ultimate kidney stone formation. Source of Funding: Research Grant from New York Academy of Medicine
INTRODUCTION AND OBJECTIVES: Costus spiralis Roscoe (C. spiralis) is a plant used in Brazilian folk medicine to treat urolithiasis; however, its’ mechanism(s) of action has yet to be elucidated. The interaction between calcium oxalate (CaOx) crystals and the renal epithelium appears important in calculogenesis, and compounds that modulate this process or other aspects of crystal formation represent candidate therapeutic agents for stone prevention. Therefore, we assessed the inhibitory activity of C. spiralis on CaOx crystallization and the interaction of CaOx crystals with the renal epithelium. METHODS: A seeded CaOx monohydrate (COM) crystallization system was used to study the effect of C. spiralis on crystal growth. Madin Darby canine kidney (MDCK) cells were used to study [14C] COM crystal adhesion in the presence and absence of an aqueous extract of C. spiralis. Cytotoxicity was assessed using a tetrazolium (MTS) cell proliferation assay. RESULTS: Aqueous C. spiralis extract decreased crystal growth in a concentration-dependent manner. The extract decreased crystal adhesion to MDCK cells in a concentration-dependent fashion (Fig. 1). Precoating crystals was effective, while pretreating cells had no effect. The extract was not cytotoxic in concentrations up to 1000 g/ml. No crystal growth or adhesion activity was found in hexane, methyl chloride, n-butanol, ethyl acetate or water fractions of an ethanol extract of the herb, suggesting that activity may reside in a polar compound. CONCLUSIONS: Our findings suggest that C. spiralis contains a compound(s) that may delay calculogenesis by interacting with CaOx crystal surfaces. As activity was present in an aqueous extract, this agent may be bioavailable when administered orally. Preliminary fractionization trials suggest that the active agent might be a polar compound such as a polysaccharide and further identification and characterization appears warranted.
Source of Funding: This work was supported by the Mayo Clinic O’Brien Urology Research Center P50 DK083007 and the Mayo Foundation.
2060 DIETARY OXALATE: WHAT’S IMPORTANT AND WHAT ISN’T FOR PATIENTS WITH CALCIUM OXALATE STONES? Kristina L. Penniston*, Katrina F. Wojciechowski, Stephen Y. Nakada, Madison, WI INTRODUCTION AND OBJECTIVES: Dietary oxalate may account for up to 50% of urinary oxalate in individuals with calcium oxalate urolithiasis. In patients with hyperoxaluria, reducing dietary