Are Anti–Oxidized Low-Density Lipoprotein Antibodies Pathogenic or Protective?

Abstract

Despite a recent decline, atherosclerosis remains the most common cause of death in the Western world. The disease course of atherosclerosis is characterized by its chronicity, with progression in its initial stages being particularly insidious. Chronic inflammation is the pathological hallmark of atherosclerosis,1–4 and inflammatory processes are instrumental at all stages of this disease. Even before the development of detectable intimal lesions, the expression pattern of the endothelium has been shown to be inflammatory in nature, conforming to the response-to-injury hypothesis first postulated by the late Russell Ross.5 Thus, in lesion-prone sites of the arterial tree, the endothelial expression of adhesion molecules is upregulated, reflecting endothelial dysfunction secondary to unfavorable blood rheology6 and/or hypercholesterolemia.7–9 Atherosclerosis is known today to be associated with the burden of infection as well.10 The presence of infectious/inflammatory pathogeneses raises the autoimmune aspect of the condition.11–14 Anti–oxidized LDL (oxLDL) antibodies are exceptional among the autoantibodies prevalent in atherosclerosis: on the one hand, a correlation was found between the existence and titers of anti-oxLDL antibodies and the extent of atherosclerosis and cardiovascular disease (CVD) (Table 1). On the other hand, experimental data indicate that anti-oxLDL antibodies may be protective. View this table: TABLE 1. Correlation Between Titers of Anti-oxLDL Abs and Atherosclerosis and CVD oxLDL frequently presents in the sera of patients with autoimmune conditions, acute coronary syndrome, or stable coronary artery disease (CAD).15–18 OxLDL has been associated with both subclinical atherosclerosis and inflammatory variables.19 A large amount of oxLDL accumulates in atherosclerotic plaques,20–22 and the serum concentrations of circulating oxLDL may correlate with the severity of CAD23 and acute coronary syndrome.24 OxLDL seems to be an immunogenic molecule that stimulates the induction of anti-oxLDL antibodies. Thus, it is not surprising that an association was found between the presence …