Abstract: The present invention is based upon the discovery that endothelial cells exposed to atheroprotectiveflow increase expression of the transcription factor KLF2 via a distinct flow-mediated signaling pathway and that this, in turn, modulates the activity of a series of genes that are responsible for maintaining the cells in an atherosclerosis-resistant state. By carrying out analyses to determine the extent to which endothelial cells are expressing these genes, a determination can be made concerning whether they are in a healthy state and factors can be examined for their effect on this state. In addition, the invention includes microarray plates or slides that can be used in carrying out such analyses.