Aerospace medical factor gene expression patterns in live subjects persist in aviation accident victims within muscle, blood, and brain (981.6)

Abstract

In support of our efforts to validate gene expression markers for aerospace medical factors such as mild hypoxia, sleep deprivation, and alcohol use, we compared gene expression patterns between aviation accident victim samples and live subject samples. RTqPCR was performed against a panel of markers and 15 potential normalizers. Microarray data was taken from a publically available dataset of fresh post‐mortem tissue samples or our own marker discovery efforts in blood.RNA integrity from tissues was poor, ranging from RINs of 0 in most brain samples to 5 in some muscle samples. RINs in blood ranged from 2 to 6. In both tissues and blood, purity was high: A260/A280 ratios between 1.9 and 2.1. Post‐mortem interval did not correlate with quality measures or yield.Expression patterns of the gene panel within tissues between the microarray (live subjects) and RTqPCR (accident victims) data were compared by Spearman correlation coefficient. Because in qPCR data, higher Ct values reflect lower gene expression, negative coefficients were expected. Skeletal muscle (‐0.50), blood (‐0.48), brain (‐0.48), cardiac muscle (‐0.47), and lung (‐0.44) had the best correlations. Expression patterns within accident victim blood samples were highly correlated (r>0.80) suggesting that degradation was irrespective of accident conditions or post‐mortem interval.In the future, it is expected that accident investigators will utilize gene expression data to determine aviation accident causality. However, to translate tests developed in live subject studies to the field, it must be demonstrated that assays are robust to RNA degradation. These results demonstrate that in some tissues, relative gene expression patterns remain stable post‐mortem and assay development can remain focused on discovering the most accurate markers without regard for potential differential stability between mRNAs.