Bilirubin loading of the heart: a novel treatment for ischemia‐reperfusion injury (667.5)

Abstract

Cardiovascular Disease (CVD) is the world’s greatest killer, claiming the lives of around 17.2 million men and women per year. Bilirubin is a novel antioxidant, which has been cited to reduce ischemia‐reperfusion injury in various tissues; however research into cardiac ischemia‐reperfusion injury is yet to be completed. The aim of this research was to determine whether exogenous bilirubin is capable of reducing ischemia‐reperfusion injury, in the heart. Young male (12 weeks old) Wistar isolated rat hearts were treated with bilirubin (50mM) for a period of 30 minutes before (Pre) or after (Post) a 30 minute no flow ischemic period. As well as functional recovery, tissue damage was measured by collecting effluent samples and quantifying infarct size. The left atria was removed from each heart after their respective treatment periods to allow analysis, through Pearson's correlation, of recovery and bilirubin concentration in the tissue. Diastolic pressure in both Pre and Post treated hearts was most significantly reduced after 90 minutes of reperfusion (Control, 81.01±14.73 mmHg, Pre, 58.92±14.23 mmHg, Post, 64.74±13.21 mmHg). The pre‐treated hearts revealed a significant recovery in left ventricular developed pressure (LVDP) in comparison to controls (Control, 34.72±12.67 %, Pre, 54.32±12.87 %). In addition, biomarkers of tissue damage, as well as infarct area, were significantly reduced in both pre‐treated and post‐treated hearts, in comparison to controls. Although the mechanisms are still unclear, this data suggests that bilirubin loading on the heart, either before or after ischemic insult, can preserve heart tissue and function.