34th Annual Scientific Meeting proceedings

Objectives:

Many conditions and causes of death involve hypoxic ischaemic events, including colic, stroke and myocardial infarction. Accurate detection and quantification of ischaemia is imperative for early diagnosis, treatment, and prognosis of these disorders. Currently used detection methods are time consuming, expensive and may lack accuracy. This study utilised an equine limb tourniquet model to assess the viability of a newly developed in vivo oxidative status biosensor to instantly measure ischaemia by comparing the IVOS biosensor correlation to isoprostane biomarkers associated with ischaemic events. 

Methods:

Six clinically healthy horses’ forelimb cephalic veins were catheterised to collect blood samples, with one forelimb acting as internal control and the other as treatment limb. IVOS biosensors was placed subcutaneously to simultaneously measure oxidative status in both limbs. A pneumatic tourniquet was inflated on a randomly selected forelimb proximal to the catheter and implanted IVOS biosensor for 30 minutes to induce ischaemia. Serial blood samples for isoprostane quantification were collected from both limbs during and after tourniquet release. Samples were centrifuged, plasma was aliquoted, stored at -80C for isoprostane quantification using liquid chromatography-tandem mass spectrometry and ex vivo oxidative status of plasma also using the IVOS biosensor.

Results:

IVOS biosensor and isoprostane measurements showed correlation and increased in a time-dependent manner. 2,3dinor-15-F2t-IsoP isoprostanes are significantly elevated in tourniquated limbs when compared to control limbs over the time of inflation.

Conclusions:

This study provides preliminary evidence that instant dynamic IVOS measurements can be successfully conducted in animals to quantify ischaemia utilising the IVOS biosensor.