Exposure to 60 minutes of hyperoxia upregulates myocardial humanins in patients with coronary artery disease

Background. In experimental setting the concept of myocardial preconditioning-by hyperoxia has been introduced and different intracellular protective mechanisms and their effects have been described. To study whether similar protective phenotype can be induced by hyperoxia also in humans, gene expression profile after hyperoxic exposure was analyzed. Methods and Findings. Adult patients were randomized to be ventilated with either FiO2 0.4 (n=14) or 1.0 (n=10) for 60 minutes before coronary artery bypass grafting. A tissue sample from the right atrial appendage was taken for gene analysis and expression profile analysis on genome wide level by gene chip analysis was applied. Exposure to > 96% oxygen for 60 minutes significantly changed the expression of 20 different genes, including upregulation of two different humanins - MTRNR2L2 and MTRNR2L8, and activated a “cell survival” network as detected by Ingenuity Pathway Analyses. Conclusions. Administration of > 96% oxygen for 1 hour changes gene expression in the myocardium of the patients with coronary artery disease and may enhance cell survival capability. Background. In experimental setting the concept of myocardial preconditioning-by hyperoxia has been introduced and different intracellular protective mechanisms and their effects have been described. To study whether similar protective phenotype can be induced by hyperoxia also in humans, gene expression profile after hyperoxic exposure was analyzed. Methods and Findings. Adult patients were randomized to be ventilated with either FiO2 0.4 (n=14) or 1.0 (n=10) for 60 minutes before coronary artery bypass grafting. A tissue sample from the right atrial appendage was taken for gene analysis and expression profile analysis on genome wide level by gene chip analysis was applied. Exposure to > 96% oxygen for 60 minutes significantly changed the expression of 20 different genes, including upregulation of two different humanins - MTRNR2L2 and MTRNR2L8, and activated a “cell survival” network as detected by Ingenuity Pathway Analyses. Conclusions. Administration of > 96% oxygen for 1 hour changes gene expression in the myocardium of the patients with coronary artery disease and may enhance cell survival capability. Overall design: 24 samples, 14 controls and 10 with intervention