title: Non-targeted metabolite profiling reveals changes in oxidative stress, tryptophan and lipid metabolisms in fearful dogs.
abstract: BACKGROUND
  Anxieties, such as shyness, noise phobia and separation anxiety, are common but poorly understood behavioural problems in domestic dogs, Canis familiaris. Although studies have demonstrated genetic and environmental contributions to anxiety pathogenesis, better understanding of the molecular underpinnings is needed to improve diagnostics, management and treatment plans. As a part of our ongoing canine anxiety genetics efforts, this study aimed to pilot a metabolomics approach in fearful and non-fearful dogs to identify candidate biomarkers for more objective phenotyping purposes and to refer to potential underlying biological problem.
  
  
  METHODS
  We collected whole blood samples from 10 fearful and 10 non-fearful Great Danes and performed a liquid chromatography combined with mass spectrometry (LC-MS)-based non-targeted metabolite profiling.
  
  
  RESULTS
  Non-targeted metabolomics analysis detected six 932 metabolite entities in four analytical modes [RP and HILIC; ESI(-) and ESI(+)], of which 239 differed statistically between the test groups. We identified changes in 13 metabolites (fold change ranging from 1.28 to 2.85) between fearful and non-fearful dogs, including hypoxanthine, indoxylsulfate and several phospholipids. These molecules are involved in oxidative stress, tryptophan and lipid metabolisms.
  
  
  CONCLUSIONS
  We identified significant alterations in the metabolism of fearful dogs, and some of these changes appear relevant to anxiety also in other species. This pilot study demonstrates the feasibility of the non-targeted metabolomics and warrants a larger replication study to confirm the role of the identified biomarkers and pathways in canine anxiety.
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland. jennipuu@student.uef.fi.
authors: Jenni
authors: J
authors: Puurunen
authors: Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Biomedicum Helsinki, P.O. Box 63, 00014, Helsinki, Finland. katriina.tiira@helsinki.fi.|The Folkhälsan Research Center, Helsinki, Finland. katriina.tiira@helsinki.fi.
authors: Katriina
authors: K
authors: Tiira
authors: School of Pharmacy, University of Eastern Finland, Kuopio, Finland. marko.lehtonen@uef.fi.|LC-MS Metabolomics Center, Biocenter Kuopio, Kuopio, Finland. marko.lehtonen@uef.fi.
authors: Marko
authors: M
authors: Lehtonen
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland. kati.hanhineva@uef.fi.|LC-MS Metabolomics Center, Biocenter Kuopio, Kuopio, Finland. kati.hanhineva@uef.fi.
authors: Kati
authors: K
authors: Hanhineva
authors: Department of Veterinary Biosciences and Research Programs Unit, Molecular Neurology, University of Helsinki, Biomedicum Helsinki, P.O. Box 63, 00014, Helsinki, Finland. hannes.lohi@helsinki.fi.|The Folkhälsan Research Center, Helsinki, Finland. hannes.lohi@helsinki.fi.
authors: Hannes
authors: H
authors: Lohi
mesh_terms: D000818:Animals; D001007:Anxiety / Q000503:physiopathology* / Q000523:psychology; D015415:Biomarkers / Q000097:blood; D002853:Chromatography, Liquid; D004285:Dogs / Q000097:blood* / Q000378:metabolism* / Q000523:psychology*; D005239:Fear / Q000502:physiology* / Q000523:psychology; D050356:Lipid Metabolism; D008297:Male; D013058:Mass Spectrometry; D055432:Metabolomics; D018384:Oxidative Stress / Q000502:physiology*; D010865:Pilot Projects; D014364:Tryptophan / Q000097:blood*
chemical_list: D015415:Biomarkers; D014364:Tryptophan