Establishment of a model for equine small intestinal disease: effects of extracorporeal blood perfusion of equine ileum on metabolic variables and histological morphology – an experimental ex vivo study

Maria S. Unterköfler, Bruce McGorum, Elspeth Milne, Theresia Licka

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Background: In horses a number of small intestinal diseases is potentially life threatening. Among them are Equine
Grass Sickness (EGS), which is characterised by enteric neurodegeneration of unknown aetiology, as well as reperfusion
injury of ischaemic intestine (I/R), and post-operative ileus (POI), common after colic surgery. The perfusion of isolated
organs is successfully used to minimize animal testing for the study of pathophysiology in other scenarios. However,
extracorporeal perfusion of equine ileum sourced from horses slaughtered for meat production has not yet been
described. Therefore the present study evaluated the potential of such a model for the investigation of small intestinal
diseases in an ex vivo and cost-efficient system avoiding experiments in live animals.
Result: Nine ileum specimens were sourced from horses aged 1–10 years after routine slaughter at a commercial
abattoir. Ileum perfusion with oxygenated autologous blood and plasma was successfully performed for 4 h in a warm
isotonic bath (37.0–37.5 °C). Ileum specimens had good motility and overall pink to red mucosa throughout the
experiment; blood parameters indicated good tissue vitality: 82 ± 34 mmHg mean arterial partial pressure of oxygen
(pO2) compared to 50 ± 17 mmHg mean venous pO2, 48 ± 10 mmHg mean arterial partial pressure of carbon dioxide
(pCO2) compared to 66 ± 7 mmHg venous pCO2 and 9.8 ± 2.8 mmol/L mean arterial lactate compared to 11.6 ± 2.7
mmol/L venous lactate. There was a mild increase in ileum mass reaching 105 ± 7.5% of the pre-perfusion mass after 4
hours. Histology of haematoxylin and eosin stained biopsy samples taken at the end of perfusion showed on average
99% (±1%) histologically normal neurons in the submucosal plexus and 76.1% (±23.9%) histologically normal neurons
in the myenteric plexus and were not significantly different to control biopsies.
Conclusion: Extracorporeal, normothermic perfusion of equine ileum over 4 h using autologous oxygenated blood/
plasma perfusate showed potential as experimental model to test whether haematogenous or intestinal exposure to
neurotoxins suspected in the pathogenesis of EGS can induce neuronal damage typical for EGS. Also, this model may
allow investigations into the effect of pharmaceuticals on I/R injury, as well as into the pathogenesis of equine POI
Original languageEnglish
JournalVeterinary Research
Early online date8 Nov 2019
DOIs
Publication statusE-pub ahead of print - 8 Nov 2019

Keywords / Materials (for Non-textual outputs)

  • Dysautonomia
  • Extracorporeal perfusion
  • Horse
  • Ileum
  • Grass sickness
  • Ileus
  • Reperfusion injury

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