title: A liquid chromatography-tandem mass spectrometry-based investigation of the lamellar interstitial metabolome in healthy horses and during experimental laminitis induction.
abstract: Lamellar bioenergetic failure is thought to contribute to laminitis pathogenesis but current knowledge of lamellar bioenergetic physiology is limited. Metabolomic analysis (MA) can systematically profile multiple metabolites. Applied to lamellar microdialysis samples (dialysate), lamellar bioenergetic changes during laminitis (the laminitis metabolome) can be characterised. The objectives of this study were to develop a technique for targeted MA of lamellar and skin dialysates in normal horses, and to compare the lamellar and plasma metabolomic profiles of normal horses with those from horses developing experimentally induced laminitis. Archived lamellar and skin dialysates (n = 7) and tissues (n = 6) from normal horses, and lamellar dialysate and plasma from horses given either 10 g/kg oligofructose (treatment group, OFT; n = 4) or sham (control group, CON; n = 4) were analysed. The concentrations of 44 intermediates of central carbon metabolism (CCM) were determined using liquid chromatography-tandem mass spectrometry. Data were analysed using multivariate (MVA) and univariate (UVA) analysis methods. The plasma metabolome appeared to be more variable than the lamellar metabolome by MVA, driven by malate, pyruvate, aconitate and glycolate. In lamellar dialysate, these metabolites decreased in OFT horses at the later time points. Plasma malate was markedly increased after 6 h in OFT horses. Plasma malate concentrations between OFT and CON at this time point were significantly different by UVA. MA of lamellar CCM was capable of differentiating horses developing experimental laminitis from controls. Lamellar malate, pyruvate, aconitate and glycolate, and plasma malate alone were identified as the source of differentiation between OFT and CON groups. These results highlighted clear discriminators between OFT and CON horses, suggesting that changes in energy metabolism occur locally in the lamellar tissue during laminitis development. The biological significance of these alterations requires further investigation.
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, Faculty of Science, The University of Queensland, Gatton Campus, Gatton, QLD 4343, Australia. Electronic address: c.medina@pferd.vetmed.uni-muenchen.de.
authors.forename: C E
authors.initials: CE
authors.lastname: Medina-Torres
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, Faculty of Science, The University of Queensland, Gatton Campus, Gatton, QLD 4343, Australia.
authors.forename: A W
authors.initials: AW
authors.lastname: van Eps
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia.
authors.forename: L K
authors.initials: LK
authors.lastname: Nielsen
authors.affiliation: Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; Metabolomics Australia - Queensland Node, AIBN, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, QLD 4102, Australia.
authors.forename: M P
authors.initials: MP
authors.lastname: Hodson
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid; D005528:Foot / Q000473:pathology*; D005534:Foot Diseases / Q000378:metabolism / Q000662:veterinary*; D006734:Horse Diseases / Q000378:metabolism* / Q000473:pathology; D006736:Horses; D007249:Inflammation / Q000378:metabolism / Q000662:veterinary*; D012867:Skin / Q000737:chemistry / Q000378:metabolism; D053719:Tandem Mass Spectrometry
keywords: Bioenergetic; Chromatography; Energy metabolism; Metabolomic; Sepsis