Untargeted Metabolic Profiling of Cat Urine and Plasma in Hypertension

Background

Early diagnosis of hypertension remains an important problem in cats. Lack of routine blood pressure screening in primary care practice, and the possibility of white coat artifact mean the discovery of a new diagnostic test, if less sensitive to short-term changes in blood pressure associated with veterinary care, would be useful. Identification of metabolomic changes in hypertensive cats could advance understanding of the pathogenesis of hypertension in cats, as well as identify novel biomarkers.

Objectives

Use untargeted metabolomics to identify biochemical changes in cat plasma and urine between normotensive controls (NT) and hypertensive cats before treatment (HTpre); HTpre and hypertensive cats treated with amlodipine (HTtx).

Animals

Biobanked surplus plasma and urine samples were selected from client-owned cats (> 9 years old) that were NT (urine n = 17, plasma n = 19), HTpre (urine n = 13, plasma n = 19), or HTtx (urine n = 12, plasma n = 19).

Methods

Samples were profiled using flow infusion electrospray—high-resolution mass spectrometry, and differences assessed using univariate (paired or two sample t-tests) and multivariate (partial least squares discriminant analysis) methods using the R-based MetaboAnalyst platform. Tentative identifications of metabolites then were made using the MZedDb database.

Results

Significant (false discovery adjusted < 0.01) biochemical differences were observed between each of the sample groups. Biochemical changes in urine between HTpre and NT animals were linked to the tricarboxylic acid cycle, oxidative stress, steroid hormones, taurine metabolism, and phosphatidylinositol-3,4,5-trisphosphate.

Conclusions

Metabolites altered in hypertensive cats were similar to those observed in other species.