Background - Calcium oxalate urolithiasis is associated with various metabolic disorders, including dyslipidemia, in humans and dogs. Improved understanding of the underlying metabolic derangements is necessary to advance urolithiasis management strategies. Hypothesis/Objectives - The objective of this study was to identify differences in serum lipidomic and metabolomic profiles between Miniature Schnauzers with and without calcium oxalate urolithiasis. Animals - Miniature Schnauzers with (n = 15, cases) and without (n = 27, controls) a history of calcium oxalate urolithiasis. Methods – Serum lipidomics and untargeted metabolomics were performed using ultrahigh performance liquid chromatography-tandem mass spectroscopy. Normalized lipid species and metabolites were compared between cases and controls using Student’s t tests with correction for multiple comparisons. Metabolites with biological links to calcium oxalate urolithiasis were designated as “high priority” and further analyzed with clustering. Results - None of 956 lipid species were identified as different between cases and controls. Three of 802 metabolites were lower in cases: 10-undecenoate, N-delta-acetylornithine, and glutarate (Praw < .001 and q < .10 for all). Cluster analysis of high priority metabolites identified five cases with a distinct pattern, characterized by lower citrate and higher phosphate, glycine, and hippurate. Conclusions and clinical importance - The absence of differentiating lipid species between cases and controls does not support dyslipidemia as a major risk factor for calcium oxalate urolithiasis in Miniature Schnauzers. The metabolites that discriminated between cases and controls are linked to nutrition and might reflect dietary differences. Distinct metabolic subsets of stone formers might exist within the breed.
