The investigators conducted this study using porcine subjects in a crossover study format as depicted in the image below. Eight male pigs each received a high oxalate diet (HOD), a low-oxalate diet (LOD), a HOD + A0 diet, and LOD + A0 diet, and a LOD + hydroxyproline (HP) diet with intervening washout periods. Urinary oxalate levels were measured by 24-hour total collection during the study period.
The results showed that A0 did, in fact, reduce urinary oxalate levels both during the HOD period (71% reduction) as well as the LOD period (45% reduction). The reduction in urinary oxalate during both phases of the study indicates that A0 is effective in reducing both dietary (demonstrated during HOD) and endogenous (demonstrated during LOD) oxalate. Notably, the pigs did not experience any adverse effects from the A0.
Dr. Bird’s work demonstrates an important concept of enzyme kinetics, as she noted that there was a larger decrease in urine oxalate during the HOD phase because the A0 enzyme had a greater amount of substrate with which to interact. However, she also mentioned that continuing to increase the concentration of A0 will have little benefit to a certain extent, as all substrate (oxalate) will eventually become bound by the enzyme.
Presented by: Victoria Bird, MD, Assistant Professor of Urology, Affiliate Professor of Biomedical Engineering, Director, U. of Florida, College of Medicine and College of Engineering, National Medical Association and Research Group LLC, Gainesville, Florida
Co-Authors: Meekah Chaderton, Meekah Chaderton, Ming Yang, Qing-Shan Li, Haifen Liu, Aaron Cowley
Author Affiliation: University of Florida College of Medicine and College of Engineering, Gainesville, Florida, USA
Written by: Frank Jefferson, Department of Urology, University of California-Irvine, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France