Effects of Ischemia on Gene Expression

摘要: Microarray gene expression technology has recently made it feasible to characterize the RNA of thousands genes across numerous tissue samples. We hypothesized that warm ischemia commonly associated with surgical extirpation human would have significant effects on profiles. To quantitate tissue, we rapidly dissected normal mucosa from a colon cancer specimen. The specimen was divided and maintained at room temperature until snap-frozen in liquid nitrogen. Aliquots were frozen times 5, 10, 15, 20, 40, 60 min after extirpation. Spotted microarrays composed 2400 distinct elements used assay mRNA derived each time point triplicate. Eisen's hierarchical clustering methodology Bayesean statistical methods then expression. Application time-course models suggest three patterns induced by ischemia, accounting for 68.2, 17.8, 13.4% evaluable genes, respectively. Pattern I corresponds an average change 27% over 5 baseline level 63.8% least 80% probability membership this pattern show increases min. remainder decrease average. II ischemia-related effects, demonstrating only 12% In contrast I, find 67.5% are decreasing time. remaining 32.5% increase Finally, III (13.4% sample) greatest sensitivity changing 50% min, about same number increasing as decreasing. Fold changes over- or under-expression observed up greater than 20-fold. Warm tissues expression. These data support careful monitoring ischemic harvested purposed profiling.