2152 OXALATE STIMULATES THE PRODUCTION OF FIBRONECTIN VIA TGF- β1-DEPENDENT ACTIVATION OF NADPH OXIDASE IN RENAL EPITHELIAL CELLS

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were not significantly different among the groups. When 24-week-old male OLETF, that had already developed type 2 diabetes, were submitted to the same protocol, similar results were obtained. CONCLUSIONS: The results indicate that weight loss intervention reduces the risk of uric acid stone formation by improving low urine pH and CaOx stone formation by increasing urinary citrate excretion. The present study provides the first theoretical evidence to recommend weight loss intervention program for nephorolithiasis patients with MetS.

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addressing total Na intake. Detailed and specific Na-reducing strategies must be provided to patients to address the majority of their Na intake. Source of Funding: AUA Foundation

2151 FORMATION AND GROWTH OF RANDALL’S PLAQUES: AN ULTRASTRUCTURAL STUDY OF RENAL PAPILLAE FROM IDIOPATHIC STONE FORMERS Saeed Khan*, Benjamin Canales, Gainesville, FL; Manoj Monga, Cleveland, OH

Source of Funding: None

2150 THE SALT SHAKER PROVIDES LESS THAN 15% OF TOTAL SODIUM INTAKE IN STONE FORMERS: FOOD STRATEGIES TO REDUCE SODIUM ARE NEEDED Kristina L. Penniston*, Katrina F. Wojciechowski, Stephen Y. Nakada, Madison, WI INTRODUCTION AND OBJECTIVES: Hypercalciuria is a major risk factor for calcium stones, and the majority of calcium stone formers have some degree of hypercalciuria in repeated 24-h urine analyses. Dietary sodium chloride exerts a significant calciuric effect and interferes with diuretic medications aimed at reducing urinary calcium excretion. We characterized the sodium (Na) intake of calcium stone formers and determined its major food sources. METHODS: Calcium stone formers undergoing medical management in our clinic were trained to provide 4-day weighed diet records. 83 subjects (M:F, 50:28; 58 and 54 years, respectively) submitted evaluable diet records which were analyzed using the Nutrition Data System for Research nutrient anlysis software (University of Minnesota). Mean Na intakes were calculated. Individual foods were separated by a Registered Dietitian into food groups, and overall contribution to Na intake was calculated. RESULTS: Mean Na intake was high (3,300 ⫾ 115 SE mg/d), exceeding the recommended daily value (2,400 mg), despite that most patients had received Na-reducing nutrition recommendations at some point during their care. Mean daily Na intake of male stone formers was higher than women (3,595 ⫾ 130 vs. 2,770 ⫾ 184 mg⫾SE; p⫽0.0003), but on a kcal-adjusted basis there was no difference in intake. More than 85% of total Na was from foods, not “the salt shaker,” which accounted for only 13.8% of Na intake. There were 6 food groups that accounted for 60% of total Na intake. They were: processed & luncheon meats (15%); bread & baked goods (14.1%); canned & pickled goods (8.5%); salad dressings, condiments, & sauces (8.4%); cheese (7.2%); and salty snacks (6.8%). CONCLUSIONS: The Na intake of calcium stone formers is high and comes less from added salt than from processed foods, baked goods, condiments, cheese, and snacks. Recommendations for calcium stone formers to “avoid the salt shaker” are insufficient in

INTRODUCTION AND OBJECTIVES: Idiopathic calcium oxalate (CaOx) kidney stones develop by deposition of CaOx crystals on Randall’s plaques (RP) present on renal papillary surfaces. RPs consist of calcium phosphate (CaP). It is our hypotheses that Randall’s plaque formation is similar to vascular calcification involving components of extracellular matrix including membrane bound vesicles and collagen fibers. In order to verify our hypothesis we critically examined renal papillary tissue from stone patients obtained at time of stone removal. METHODS: After IRB approval and informed consent, cold-cup biopsy of renal papilla was performed on 10 idioptahic stone patients undergoing PCNL. Stones were analyzed using FTIR/polarizing optics. Kidney tissue was immediately fixed and later processed for light and electron microscopic analyses. Paraffin embedded sections were examined after H&E and PAS staining. Selected samples were also stained for collagen and osteopontin (OPN). All samples were examined by transmission electron microscopy (TEM). Because of small specimen size, some were first examined by scanning electron microscopy (SEM) and then TEM and light microscopy. RESULTS: Spherulitic CaP crystal deposits, the hallmark of RP’s, were seen by TEM in all samples examined. They were seen in the interstitium as well as laminated basement membrane of tubular epithelia. Five specimens contained large crystalline deposits. These were aggregates of needle shaped as well as plate-like crystals. Energy dispersive x-ray microanalyses (EDX) identified them as CaP. Individual spherulites were often surrounded by membrane bound vesicles. Many such vesicles either contained or seen associated with individual needle shaped crystals. Some of the crystals present in the interstitium were closely aligned with collagen fibers. EDX analyses of such collagen associated deposits determined that they contained calcium and phosphorus. Crystal deposits stained positive for the presence of osteopontin by light microscopic immuno-histochemical analyses. CONCLUSIONS: Results presented here show that crystals in the Randalls’ plaques are associated with both the collagen as well as membrane bound vesicles and stain positive for osteopontin. The vesicles contained needle shaped crystals. We conclude that crystal deposition in renal papillae may have started with membrane vesicle induced nucleation and grew by addition of crystals on the periphery within a collagen framework. Mineralization was most likely modulated by various proteins one of them being osteopontin. Source of Funding: University of Florida Center for the Study of Lithiasis and Pathological Calcification

2152 OXALATE STIMULATES THE PRODUCTION OF FIBRONECTIN VIA TGF- ␤1-DEPENDENT ACTIVATION OF NADPH OXIDASE IN RENAL EPITHELIAL CELLS Vijayalakshmi Thamilselvan, Mani Menon, Sivagnanam Thamilselvan*, Detroit, MI INTRODUCTION AND OBJECTIVES: Hyperoxaluria is one of the major risk factors for calcium oxalate nephrolithiasis. We have previously demonstrated that oxalate induces reactive oxygen species (ROS) mediated cell injury via NADPH oxidase activation in renal epithelial cells. Generation of Inflammatory mediators and excessive

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accumulation of extracellular matrix proteins in the kidneys contributes to the renal fibrosis. Since there is a strong association between hyperoxaluria and tubulointerstitial scarring, we investigated whether oxalate-induced TGF- ␤1 can stimulate the production of fibronectin (FN) via NADPH oxidase mediated ROS production in renal epithelial cells. METHODS: Confluent monolayers of LLC-PK1 cells pretreated with inhibitors of NADPH oxidase (DPI or apocynin) or neutralizing antibody to TGF- ␤1 were exposed to 0.75 mM oxalate for different time periods. Recombinant TGF- ␤1 was used as a positive control. ROS generation and LDH release were determined. Expression of TGF- ␤1 mRNA was analyzed by RT-PCR. Fibronectin and TGF- ␤1 levels were measured in culture supernatants by ELISA. TGF- ␤1 and FN protein expression were determined by western blot analysis. NADPH oxidase activity was determined by SOD-inhibitable cytochrome c reduction assay. RESULTS: Oxalate time dependently stimulated FN expression and secretion in LLC-PK1 cells. TGF- ␤1 mRNA and protein expression were augmented by oxalate exposure. Oxalate significantly increased NADPH oxidase activity in LLC-PK1 cells. Treatment with TGF ␤1 neutralizing antibody significantly inhibited oxalate -induced NADPH oxidase activity, ROS production and LDH release. The stimulatory effect of oxalate on FN secretion was inhibited by neutralizing antibodies against TGF- ␤1. Recombinant TGF- ␤1 dose dependently increased ROS generation, LDH release and FN expression and secretion in LLC-PK1 cells. In addition, pretreatment with NADPH oxidase inhibitors significantly decreased oxalate or recombinant TGF- ␤1 induced ROS generation, FN expression and secretion. CONCLUSIONS: Our findings demonstrate that TGF- ␤1-dependent activation of NADPH oxidase mediated ROS play an important role in oxalate-induced FN accumulation and development of renal interstitial fibrosis, and suggest that ROS signaling pathways may represent a novel therapeutic target to prevent the progression of tubulointerstitial fibrosis in patients with kidney stones. Source of Funding: NIH RO1 DK 56249

2153 METABOLIC ABNORMALITIES OF UROLITHIASIS PATIENTS WITH 25-HYDROXY VITAMIN- D DEFICIENCY Mohamed Elkoushy*, Ramsey Sabbagh, Bernard Unikowsky, Sero Andonian, Montreal, Canada INTRODUCTION AND OBJECTIVES: Vitamin D deficiency and replacement has risen in popularity in recent years. However, there is no data characterizing the metabolic abnormalities in vitamin D deficient patients presenting with urolithiasis. The aim of this work was to determine urinary and serum abnormalities in patients presenting with urolithiasis and found to have 25-hydroxy vitamin D deficiency. METHODS: A retrospective review of our prospectively collected data was performed to identify patients with 25, hydroxy vitamin D (VD) deficiency from August, 2009 to Jan, 2010. Patients with VD ⬍ 74 nmol/L were included and their demographic, medical and surgical data were recorded. Metabolic stone workup including 24-hours urine collection, serum calcium, PTH, TSH, and uric acid were performed. RESULTS: Sixty-nine patients were included in the study of whom 37 (53.6%) were males with a mean age of 50.4⫾15.8 years (range: 14 – 87) and a mean BMI of 27.4⫾ 6.6. Fifty-one percent had past history of urolithiasis and 54.1% had family history of stone disease. Secondary hyperparathyroidism was detected in 25.3% of these patients. Normalized ionized calcium was low in 36.2% of patients. Hyperuricemia was found in 11% of patients. Ninety-three percent of the 24-hours urine collections had at least one abnormality. The most prevalent patterns of urinary abnormalities in decreasing frequency were suboptimal urine volume (⬍2 L/day) in 45%, hypocitaturia in 24%, hypercalciuria in 20%, hyperuricosuria in 16%, cystinuria in 5%, and hyper-oxaluria in 3% of patients. Interestingly, 33% of patients had hypocalciuria.

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CONCLUSIONS: Patients with 25- hydroxy VD deficiency have high incidence of abnormalities on metabolic stone workup. The relationship between vitamin D deficiency and these findings needs to be further evaluated. Source of Funding: None

2154 ANTIBIOTIC PRESCRIPTION AND POOR COMPLIANCE WITH AUA BEST PRACTICE STATEMENT Brian Eisner, Michael Kurtz*, Boston, MA; Stuart Wolf, Jr, Ann Arbor, MI INTRODUCTION AND OBJECTIVES: In 2008 the AUA published a best practice statement regarding antibiotic prophylaxis for all urologic procedures. In 2009, we performed an online survey through the Society of Endourology which demonstrated that compliance with these guidelines was quite poor, with approximately 69% of respondents prescribing antibiotics in excess of best-practice recommendations. The current study was undertaken to examine the current state of compliance with these guidelines. METHODS: A blast email restating practice guidelines was sent via the Endourological Society list serve (n ⫽ estimated at 1500). This email blast reiterated the AUA Best Practice Statement on antibiotic prophylaxis. Two weeks later, an online anonymous secure survey was sent. Unique results were tabulated and reviewed. RESULTS: In one year after in the initial survey, a minority of respondents reported prescription patterns compliant with guidelines, but the number has increased from 30.4% (2009) to 40% (present). When queried about factors that influenced decisions about postoperative antibiotics, 56.6% of respondents cited AUA Best Practice Statement published in 2008, 5.2% cited our initial abstract presented at AUA 2009 annual meeting, and 13% cited the email blast sent two weeks prior to the current survey.There were no significant differences between the respondents reporting compliant behavior with respect to the type of stenting used; no stent in 31.9 vs 26.3%, externalized catheter in 8.4 vs 10.3%, stent with a tether in 25.9 vs 27.6%, or cystoscopic removal in 41.2 vs. 48.3%. Doses prescribed in excess of AUA recommendations in the last 12 months by the survey respondents alone exceeded 3,628 doses of penicillin / cephalosporin, 2,670 doses of quinolone, 1,177 doses of trimethoprim, and 180 doses of nitrofurnatoin. CONCLUSIONS: Compliance with AUA Best Practice guildines for antibiotic prophylaxis after surgery is poor (40%). AUA published guidelines appear to have the greatest influence on this, but meeting abstracts and email blasts may also be useful for disseminating this type of information as well. There is great need, however, for improving methods of dissemination and enhancing compliance with clinical practice guidelines. Source of Funding: None

2155 ASSESSING THE USE OF HEMOSTATIC SEALANTS IN TUBELESS PERCUTANEOUS NEPHROSTOMY: THE EFFECTS ON RENAL HISTOLOGY IN AN EXPERIMENTAL PORCINE STUDY Christos Rigopoulos, Panagiotis Kallidonis*, Iason Kyriazis, Odysseas Andrikopoulos, Constantinos Constantinidis, Patras, Greece; Jens-Uwe Stolzenburg, Leipzig, Germany; Evangelos Liatsikos, Patras, Greece INTRODUCTION AND OBJECTIVES: Despite the relative common use of hemostatic sealants in tubeless percutaneous nephrolithotomy (PCNL) in the clinical practice, various experimental settings have questioned the safety of this application. These studies are mainly focusing on the potential of such materials to occlude urinary drainage. In this study, we question again the safety of various types of hemo-