Do chronic fatigue syndrome and atherosclerosis share common molecular risk factors?

Abstract

In the past 50 years, numerous studies have identified novel risk factors for atherosclerosis. Chronic fatigue syndrome (CFS), an illness characterized by lasting disabling fatigue and referred to as a 20th century phenomenon, is highly prevalent, and the number of people affected is increasing. Although the influence of physical and psychological stress factors on atherosclerosis has been recognized, the role of psychosocial risk factors has received far less attention in cardiac practice and in the research of atherosclerosis. Despite the fact that these represent highly relevant aspects of this disease, their potential role in promoting CFS has not been systematically explored. In this context, certain questions arise that need to be answered. Studies investigating oxidative stress (OS) in CFS report (i) significantly increased low-density lipoprotein (LDL) oxidation, (ii) significantly reduced plasma concentrations of high-density lipoprotein and vitamin E, (iii) a significantly reduced lag phase for ex vivo oxidized LDL, (iv) increased augmentation index normalized for a heart rate of 75 beats/ min (AIx@75), and (v) gene expression alterations of ATP-binding cassette transporters (e.g. ABCD 4) and the integral peroxisomal membrane protein PEX 16. Evidence for OS in patients with this syndrome has been strengthened by studies demonstrating increased C-reactive protein levels, high blood pressure, and increased numbers of erythrocytes in a stomatocytic form. Furthermore, there are reports of cardiovascular impairment in many CFS patients, with underlying pathomechanisms such as autonomic dysfunction, attenuated heart rate and blood pressure regulation, increased vasomotor tone, and loss of heart rate variability. These findings suggest that CFS itself is a chronic state of inflammation lasting over long periods of time from 3 to 9 years. The results of present studies suggest that there are individual risk factors, such as physical and/or psychological stress, for CFS and that it is a molecular risk factor for atherosclerosis. The presence of reactive oxygen species and chronic inflammation in atherosclerosis and CFS indicates that the two diseases may have common underlying molecular mechanisms. Copyright © 2011 S. Karger AG, Basel.