Lower Expression of Genes Involved in Protection against Oxidative Stress in Symptomatic Carotid Atherosclerosis

Abstract

Oxidative stress is increased in atherosclerosis, manifested both in blood and tissue (atherosclerotic plaque). We aim at describing the expression of a number of genes related to oxidative stress response in carotid atherosclerotic plaques and their relation to symptomatic state. We have studied the messenger RNA expression levels for genes related to oxidative stress in a population of 44 patients undergoing carotid endarterectomy, according to the presence (24 patients) or absence (20 patients) of symptoms. Samples were homogenized, RNA was extracted, and gene expression was measured by quantitative reverse transcription polymerase chain reaction arrays. Data showed a decrease in expression of oxidative stress protective genes in symptomatic patients and increased expression of pro-oxidant genes. Asymptomatic patients maintain higher levels of expression of protective genes in the tissue. This study establishes a close relationship between symptoms and levels of expression of genes that protect against oxidative stress. We propose the existence of a mechanism that silences these genes, causing a more severe atherosclerotic disease state.