SS5. Antibodies Against Malondialdehyde-Acetaldehyde Adducts Can Identify Patients With Abdominal Aortic Aneurysm

Abstract

Abdominal aortic aneurysm (AAA) is a pathologic dilation of the aorta. Inflammation of the aortic wall has been shown to be involved in AAA formation. Malondialdehyde-acetaldehyde (MAA) adducts are MAA/protein hybrids with immunogenic, proinflammatory, and profibrotic properties. Levels of MAA adducts are elevated in patients with coronary artery disease; however, the role of MAA adducts in AAA is unclear. We hypothesize that levels of circulating antibodies against MAA adducts are increased in patients with AAA. Plasma samples were collected from mice and patients with and without AAA. AAA was induced in mice by a standard CaCl2 protocol, with matching sham mice. Plasma levels of anti-MAA antibodies were quantified by enzyme-linked immunosorbent assay. Patients with AAA exhibited higher levels of immunoglobulin G (IgG) and IgA anti-MAA antibody subtypes (P = .049 and P = .026, respectively) compared with control patients. Conversely, IgM anti-MAA antibodies in AAA patients were lower compared with control patients (P = .018). In CaCl2 treated mice IgG anti-MAA antibodies were elevated after AAA formation (P = .006). The pattern of anti-MAA antibodies is able to distinguish between patients with AAA and patients with atherosclerosis but no AAA. These results demonstrate that MAA adducts are associated with AAA and suggest they may play a role in either initiating or propagating chronic inflammation in AAA.