Journal of Molecular Biomarkers and Clinical Trials

Urinary Metabolomics Profile of Genetically Obese Rats Using Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry

*Michel Aliani
Department Of Food Science And Human Nutrition, Canada, Canada

*Corresponding Author:
Michel Aliani
Department Of Food Science And Human Nutrition, Canada, Canada
Email:michel.aliani@cc.umanitoba.ca

Published on: 2018-02-09

Abstract

As the prevalence of obesity continues to increase further research investigating the body’s metabolic response to increased adiposity can help us better understand the disease and identify biomarkers that pave way for the development of new prevention and treatment strategies. The urinary metabolite profile can provide detailed information regarding the metabolic network at any disease stage and may be useful for investigating the effect of obesity on water-soluble metabolite profiles in genetically obese rats using a nontargeted metabolomics approach. Urine from 24 week old male obese fa/fa (n=8) and lean (n=8) Zucker rats were extracted and analyzed using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Data were analyzed by moderated T-test (P<0.05), fold change (≥2) and a prediction model using partial least squares discrimination analysis. The body composition of obese rats was 48.1 ± 0.9% fat compared to 16.9 ± 0.8% fat for lean rats. Untargeted urine metabolomics detected 1046 entities with 43 metabolites significantly different between obese and lean rats. Among these metabolites, N1 -methylnicotinamide, spermine, hexadecyl acetyl glycerol and 3-mercaptolactic acid were significantly elevated in the urine from obese rats. The increase of water-soluble metabolites may suggest an obesity effect on the metabolism of arginine (increased levels of spermine) as well as nicotinamide metabolism (increased levels of N1 -methylnicotinamide) which can lead to oxidative stress. Urinary metabolites observed in obese rats provided new insights into biological mechanisms associated with an obese state.

Keywords

Obesity; Urinary Metabolomics; Spermine; N1-Methylnicotinamide

Introduction

Obesity is a condition characterized by the excessive accumulation and storage of fat in the body [1]. The prevalence of obesity worldwide has more than doubled between 1980 and 2014 with 39% of adults over 18 years of age being classified as overweight (BMI ≥ 25 to ≤ 29.9 kg/m2 ) and 13% being classified as obese (BMI ≥ 30 kg/m2 ) in 2014 [2]. In Canada, approximately one in four Canadian adults are obese, according to measured height and weight data from 2007- 2009 [3]. Obesity has been deemed one of the greatest public health challenges of the 21st century and has reached epidemic proportions worldwide [2] due to its adverse health effects that reduce life expectancy in association with many chronic diseases, including hypertension, cardiovascular disease, diabetes, arthritis and certain types of cancer [4,5]. It has been estimated that 44% of diabetes, 23% of ischemic heart disease and up to 41% of cancer related cases in the world are attributable to being overweight or obese