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A UNILATERAL URETERAL OBSTRUCTION MOUSE MODEL IS APPLIED TO INVESTIGATE THE PATHOPHYSIOLOGY OF OBSTRUCTED URETERS
THE JOURNAL OF UROLOGY®
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
721
CONCLUSIONS: We conclude the UUO mouse model is appropriate for studying ureteral pathophysiology during obstruction. This is the first study to image ureteral histology and COX-2 induction in a mouse model during obstruction. This model is readily available for use in conjunction with transgenic mice (i.e. knock-out mice) or to evaluate novel pharmaceutical therapies. Source of Funding: None
Source of Funding: None
1991 Stone Disease: Research/New Technology (II)
RENAL HISTOLOGICAL CHANGES AFTER RYGB IN A DIET INDUCED OBESE RAT MODEL
Moderated Poster 68
Benjamin K Canales*, Saeed R Khan, Patricia A Glenton, Leticia Reyes, Mary K Reinhard, Gainesville, FL; Carolina G Goncalves, Michael M Meguid, Syracuse, NY
Wednesday, April 29, 2009
10:30 am - 12:30 pm
1990 A UNILATERAL URETERAL OBSTRUCTION MOUSE MODEL IS APPLIED TO INVESTIGATE THE PATHOPHYSIOLOGY OF OBSTRUCTED URETERS Kwadwo Owusu-Ofori*, Eric Wilkinson, William S Mellon, Stephen Y Nakada, Madison, WI INTRODUCTION AND OBJECTIVES: Ureteral obstruction is characterized by increases in COX-2 expression stimulating hypercontractility, inflammation and pain via increased prostanoid synthesis. The most common cause of obstruction is urolithiasis, which carries a 13% lifetime risk in the United States with recurrence risks of 50% following the initial stone event. We previously reported increased COX-2 expression in the urothelium of obstructed human and porcine tissues. The Unilateral Ureteral Obstruction (UUO) mouse model is primarily utilized to study hydronephrosis and other renal disorders that occur during ureteral obstruction. We recently reported biochemical evidence that the UUO mouse model displays COX-2 induction, however ureteral physiology during obstruction remains poorly studied. The purpose of this study is to provide further microscopic evidence that the UUO mouse model will provide a novel method to study ureteral pathophysiology during obstruction. METHODS: Male CD1 mice (12-wks old) were anesthetized, and double-ligated at the Ureteropelvic Junction (UPJ) with a 6.0 vicryl suture. Ureters were harvested, fixed in 4% formalin and paraffin embedded. Sectioned (~5microns) samples were analyzed with H&E staining or immunohistochemistry (IHC) of COX-2. RESULTS: We show that histology staining and IHC can be performed on obstructed mouse ureters. We also show COX-2 induction within 4hrs of obstruction primarily in the urothelium of obstructed mouse ureters. These results confirm our laboratory’s biochemical studies showing enhanced COX-2 expression during obstruction.
INTRODUCTION AND OBJECTIVES: Roux-en-Y gastric bypass (RYGB) surgery is the most common and effective surgical intervention for long-term weight loss in morbidly obese patients. As popularity and demand for this therapy has expanded, renal manifestations such as oxalate nephropathy and nephrolithiasis appear to be increasing in this patient population. With the intention to develop a murine model, we performed RYGB in obese rats on a high fat, normal oxalate diet and tested whether the enteric hyperoxaluria of RYGB causes detrimental renal injury and mineral deposition. METHODS: Sprague-Dawley rats, fed a high-lard diet to induce gross obesity, were randomized to RYGB (n=6), GI-intact sham-operated obese controls (Controls, n=4), or GI-intact sham-operated obese pairfed rats (PF, n=8). Daily body weight and food intake were recorded for 40 days. Food efficiency was calculated. Rats were sacrificed and renal tissue was obtained for protein and immunohistochemical analysis. Stained sections were imaged using an imaging microscope and imageanalysis software (Axioplan 4.1). Osteopontin (OPN) stain was estimated based on percentage of stained area compared to the kidney section size. ED-1 (macrophage-derived mononuclear cell stain) was estimated on the number of counted cells in each field divided by the number of fields examined. Data were compared using ANOVA and t-test. RESULTS: RYGB vs. PF control rats had significant reductions in body weight and food efficiency (p<0.001) and significantly greater renal tubule mineralization and basophilia, patchy interstitial nephritis, and glomerular changes by H&E staining. The inner medulla of the RYGB rats stained stronger for osteopontin (70% vs. 43%, p=0.01) while the outer medulla of the RYGB rats stained stronger for ED-1 (39 cells/10x field vs. 11 cells/10x field, p=0.05). CONCLUSIONS: In this rat model, RYGB surgery is associated with significant weight loss, decreased food efficiency, renal mineral deposition, and insidious, chronic renal interstitial cellular damage. Osteopontin is up-regulated within the tubular lumen and urinary space, likely due to oxalate mineralization. ED-1 positive cells are attracted to epithelial cells located within the thin loop of Henle, suggesting that the injurious mechanisms provoked by mineralization involve not only inflammation but also antigen presentation and fibrogenesis. Source of Funding: BKC is supported by NIH grant 3R01DK065658-03S1, CGG by a post-doc intramural grant (130230-30), and MMM by an American Diabetes Association grant (1-05-RA-81).
Vol. 181, No. 4, Supplement, Wednesday, April 29, 2009
721
CONCLUSIONS: We conclude the UUO mouse model is appropriate for studying ureteral pathophysiology during obstruction. This is the first study to image ureteral histology and COX-2 induction in a mouse model during obstruction. This model is readily available for use in conjunction with transgenic mice (i.e. knock-out mice) or to evaluate novel pharmaceutical therapies. Source of Funding: None
Source of Funding: None
1991 Stone Disease: Research/New Technology (II)
RENAL HISTOLOGICAL CHANGES AFTER RYGB IN A DIET INDUCED OBESE RAT MODEL
Moderated Poster 68
Benjamin K Canales*, Saeed R Khan, Patricia A Glenton, Leticia Reyes, Mary K Reinhard, Gainesville, FL; Carolina G Goncalves, Michael M Meguid, Syracuse, NY
Wednesday, April 29, 2009
10:30 am - 12:30 pm
1990 A UNILATERAL URETERAL OBSTRUCTION MOUSE MODEL IS APPLIED TO INVESTIGATE THE PATHOPHYSIOLOGY OF OBSTRUCTED URETERS Kwadwo Owusu-Ofori*, Eric Wilkinson, William S Mellon, Stephen Y Nakada, Madison, WI INTRODUCTION AND OBJECTIVES: Ureteral obstruction is characterized by increases in COX-2 expression stimulating hypercontractility, inflammation and pain via increased prostanoid synthesis. The most common cause of obstruction is urolithiasis, which carries a 13% lifetime risk in the United States with recurrence risks of 50% following the initial stone event. We previously reported increased COX-2 expression in the urothelium of obstructed human and porcine tissues. The Unilateral Ureteral Obstruction (UUO) mouse model is primarily utilized to study hydronephrosis and other renal disorders that occur during ureteral obstruction. We recently reported biochemical evidence that the UUO mouse model displays COX-2 induction, however ureteral physiology during obstruction remains poorly studied. The purpose of this study is to provide further microscopic evidence that the UUO mouse model will provide a novel method to study ureteral pathophysiology during obstruction. METHODS: Male CD1 mice (12-wks old) were anesthetized, and double-ligated at the Ureteropelvic Junction (UPJ) with a 6.0 vicryl suture. Ureters were harvested, fixed in 4% formalin and paraffin embedded. Sectioned (~5microns) samples were analyzed with H&E staining or immunohistochemistry (IHC) of COX-2. RESULTS: We show that histology staining and IHC can be performed on obstructed mouse ureters. We also show COX-2 induction within 4hrs of obstruction primarily in the urothelium of obstructed mouse ureters. These results confirm our laboratory’s biochemical studies showing enhanced COX-2 expression during obstruction.
INTRODUCTION AND OBJECTIVES: Roux-en-Y gastric bypass (RYGB) surgery is the most common and effective surgical intervention for long-term weight loss in morbidly obese patients. As popularity and demand for this therapy has expanded, renal manifestations such as oxalate nephropathy and nephrolithiasis appear to be increasing in this patient population. With the intention to develop a murine model, we performed RYGB in obese rats on a high fat, normal oxalate diet and tested whether the enteric hyperoxaluria of RYGB causes detrimental renal injury and mineral deposition. METHODS: Sprague-Dawley rats, fed a high-lard diet to induce gross obesity, were randomized to RYGB (n=6), GI-intact sham-operated obese controls (Controls, n=4), or GI-intact sham-operated obese pairfed rats (PF, n=8). Daily body weight and food intake were recorded for 40 days. Food efficiency was calculated. Rats were sacrificed and renal tissue was obtained for protein and immunohistochemical analysis. Stained sections were imaged using an imaging microscope and imageanalysis software (Axioplan 4.1). Osteopontin (OPN) stain was estimated based on percentage of stained area compared to the kidney section size. ED-1 (macrophage-derived mononuclear cell stain) was estimated on the number of counted cells in each field divided by the number of fields examined. Data were compared using ANOVA and t-test. RESULTS: RYGB vs. PF control rats had significant reductions in body weight and food efficiency (p<0.001) and significantly greater renal tubule mineralization and basophilia, patchy interstitial nephritis, and glomerular changes by H&E staining. The inner medulla of the RYGB rats stained stronger for osteopontin (70% vs. 43%, p=0.01) while the outer medulla of the RYGB rats stained stronger for ED-1 (39 cells/10x field vs. 11 cells/10x field, p=0.05). CONCLUSIONS: In this rat model, RYGB surgery is associated with significant weight loss, decreased food efficiency, renal mineral deposition, and insidious, chronic renal interstitial cellular damage. Osteopontin is up-regulated within the tubular lumen and urinary space, likely due to oxalate mineralization. ED-1 positive cells are attracted to epithelial cells located within the thin loop of Henle, suggesting that the injurious mechanisms provoked by mineralization involve not only inflammation but also antigen presentation and fibrogenesis. Source of Funding: BKC is supported by NIH grant 3R01DK065658-03S1, CGG by a post-doc intramural grant (130230-30), and MMM by an American Diabetes Association grant (1-05-RA-81).