title: Microdialysis measurements of lamellar perfusion and energy metabolism during the development of laminitis in the oligofructose model.
abstract: BACKGROUND
  Failure of lamellar energy metabolism, with or without ischaemia, may be important in the pathophysiology of sepsis-associated laminitis.
  
  
  OBJECTIVE
  To examine lamellar perfusion and energy balance during laminitis development in the oligofructose model using tissue microdialysis.
  
  
  METHODS
  In vivo experiment.
  
  
  METHODS
  Six Standardbred horses underwent laminitis induction using the oligofructose model (OFT group) and 6 horses were untreated controls (CON group). Microdialysis probes were placed in the lamellar tissue of one forelimb (all horses) as well as the skin dermis of the tail in OFT horses. Dialysate and plasma samples were collected every 2 h for 24 h and concentrations of energy metabolites (glucose, lactate, pyruvate) and standard indices of energy metabolism (lactate to glucose ratio [L:G] and lactate to pyruvate ratio [L:P]) determined. Microdialysis urea clearance was used to estimate changes in tissue perfusion. Data were analysed nonparametrically.
  
  
  RESULTS
  Median glucose concentration decreased to <30% of baseline by 8 h in OFT lamellar (P = <0.01) and skin (P<0.01) dialysate. Lactate increased mildly in skin dialysate (P = 0.04) and plasma (P = 0.05) but not lamellar dialysate in OFT horses. Median pyruvate concentration decreased to <50% of baseline in OFT lamellar dialysate (P = 0.03). A >5-fold increase in median L:G compared with baseline occurred in OFT lamellar and skin dialysate (P<0.03). From a baseline of <20, median L:P increased to a peak of 80 in OFT skin and 38.7 in OFT lamellar dialysates (P<0.02); however, OFT lamellar dialysate L:P was not significantly different from CON. Urea concentration decreased significantly in OFT lamellar dialysate (increased urea clearance) but not in OFT skin or CON lamellar dialysate.
  
  
  CONCLUSIONS
  Increased lamellar perfusion occurred during the development of sepsis-associated laminitis in the oligofructose model. Glucose concentrations in the lamellar interstitium decreased, suggesting increased glucose consumption but there was no definitive evidence of lamellar energy failure.
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: C E
authors.initials: CE
authors.lastname: Medina-Torres
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Underwood
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: C C
authors.initials: CC
authors.lastname: Pollitt
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: E M
authors.initials: EM
authors.lastname: Castro-Olivera
authors.affiliation: Metabolomics Australia - Queensland Node, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland, Australia.
authors.forename: M P
authors.initials: MP
authors.lastname: Hodson
authors.affiliation: New Bolton Center, Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Philadelphia, USA.
authors.forename: D W
authors.initials: DW
authors.lastname: Richardson
authors.affiliation: Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: A W
authors.initials: AW
authors.lastname: van Eps
mesh_terms: D000818:Animals; D005260:Female; D005534:Foot Diseases / Q000473:pathology / Q000662:veterinary*; D006724:Hoof and Claw / Q000473:pathology*; D006734:Horse Diseases / Q000139:chemically induced* / Q000473:pathology; D006736:Horses; D007249:Inflammation / Q000473:pathology / Q000662:veterinary*; D008297:Male; D017551:Microdialysis / Q000295:instrumentation / Q000379:methods / Q000662:veterinary; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods / Q000662:veterinary; D009844:Oligosaccharides / Q000633:toxicity*
chemical_list: D009844:Oligosaccharides; C120489:oligofructose
keywords: bioenergetics; horse; metabolite; microdialysis; oligofructose