Microarrays

Over the last 10 to 20 years, the search for mechanisms responsible for cardiac remodeling during cardiac hypertrophy and failure has been hampered by the experimental tools available (primarily Western blot analysis and polymerase chain reaction). This is because these approaches only permit measurement of the expression levels of a few preselected genes at one time. However, there is increasing evidence that at the molecular level the changes that occur during development of heart failure represent a complex series of interrelated events.1 2 3 Thus, to identify the full scope and complexity of the subcellular changes that take place and thus make more rapid progress in identifying causes and cures of heart disease, we must depend on emerging high-throughput gene-profiling technologies. These newer approaches permit expression screening of very large numbers of genes simultaneously and then clustering of the results into functional gene families.4 5 As stated by Weinstein et al,6 “We will have to understand our favorite biological molecule in the context of many thousands of others … a wide net must be cast to be sure that we have, in fact, found the important ones …” (p. 627).Both cDNA7 and oligonucleotide arrays8 permit an unbiased assessment (ie, no preselection required) of expression levels of thousands of full-length genes, cDNAs, or expressed sequence tags. In a relatively short period of time, …