Abstract
The incidence of calcium oxalate (CaOx) urolithiasis in dogs has increased steadily over the last two decades. A potential mechanism to minimize CaOx urolithiasis is to reduce enteric absorption of dietary oxalate by oxalate-metabolizing enteric bacteria. Enteric colonization of Oxalobacter formigenes, an anaerobe which exclusively relies on oxalate metabolism for energy, is correlated with absence of hyperoxaluria or CaOx urolithiasis or both in humans and laboratory animals. We thus hypothesized that decreased enteric colonization of O. formigenes is a risk factor for CaOx urolithiasis in dogs. Fecal samples from dogs with CaOx uroliths, clinically healthy, age-, breedand gender-matched dogs, and healthy non-stone forming breed dogs were screened for the presence of O. formigenes by quantitative PCR to detect the oxalyl CoA decarboxylase (oxc) gene, and by oxalate degrading biochemical activity in fecal cultures. Prevalence of O. formigenes in dogs with CaOx uroliths was 25%, compared to 50% in clinically healthy, age-, breed- and gender-matched dogs, and 75% in healthy non-stone forming breeds. The presence of oxc genes of O. formigenes was significantly higher in healthy non-stone forming breed dogs than in the dogs with CaOx stones. Further, dogs with calcium oxalate stones and the stone-forming breed-matched controls showed comparable levels of biochemical oxalate degrading activity. We conclude that the absence of enteric colonization of O. formigenes is a risk factor for CaOx urolithiasis.
Original language | English (US) |
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Pages (from-to) | 467-473 |
Number of pages | 7 |
Journal | Urological Research |
Volume | 40 |
Issue number | 5 |
DOIs | |
State | Published - Oct 2012 |
Bibliographical note
Funding Information:Acknowledgments We thank Dr. M. Allison, Iowa State University, for technical advice on anaerobic culture and for kindly providing the O. formigenes-positive culture. Dr. Carl A. Osborne, Department of Veterinary Clinical Sciences, University of Minnesota, for his vision and encouragement in initiating studies of canine urolithiasis and establishing the Urolith Center through which the animals in this study were recruited. Dr. H. Albasan and staff of Minnesota Urolith Center assisted in sample collection. Dr. R. Knurr, Department of Geology and Geophysics, University of Minnesota, performed the ion chromatographic analyses. This study was funded by the Morris Animal Foundation grants D08CA-154 and DO8CA-408.
Keywords
- Calcium oxalate
- Dogs
- Oxalobacter formigenes
- Urolithiasis