Lipoprotein(a) in plasma, arterial wall, and thrombus from patients with aortic aneurysm

Abstract

The plasma concentration of lipoprotein(a) [Lp(a)] is highly correlated with the incidence of cardiovascular and peripheral vascular disease. A positive physiological role for Lp(a) has not yet been clearly identified, although elevated plasma levels in pregnant women, long‐distance runners, subjects given growth hormone, patients after cardiovascular surgery, and patients with cancer, diabetes, or renal disease suggest its involvement in tissue synthesis and repair. The hypothesis that Lp(a) is involved in repair/reinforcement of the aorta was tested in 38 patients undergoing surgery for aortic aneurysm. In 29 patients 1 day before surgery, the mean plasma Lp(a) protein level was 10.7 mg/dl. At about 1, 2, and 8 weeks after surgery, the level was 14.1, 15.1, and 15.2 mg/dl, respectively. These levels are significantly higher than those of a comparable group of normal subjects (6.4 mg/dl; n = 274). Specimens of resected aortic aneurysm showed extensive medial degeneration, discontinuous elastic fibers, and deposition of mucopolysaccharides; these specimens were treated with a detergent‐containing buffer to extract entrapped lipoproteins. The mean Lp(a) protein level in aortic wall extracts was 14.6 ng/mg tissue; these individual values were significantly associated with plasma Lp(a) levels before surgery (r2= 0.31, p = 0.0003). The mean Lp(a) protein level in aortic thrombus extracts was substantially higher at 69.6 ng/mg tissue; these individual levels also were significantly associated with plasma Lp(a) concentrations before surgery (r2= 0.68, p < 0.0001). The observations that: (i) plasma Lp(a) protein is about 1.7‐fold higher in patients with aortic aneurysms than in normal subjects; and (ii) that Lp(a) protein in the aneurysmic thrombus is about 4.8‐fold higher than in the aortic wall suggest that this lipoprotein plays a significant and direct role in thrombus formation and in reinforcement of the aneurysmic aortic wall.

Analysis of serum levels and cutaneous expression of lipoprotein (a) in 38 patients with livedoid vasculopathy

“…We found that patients with LV exhibited high levels of Lp(a) in their skin, significantly higher than control skin, supporting the potential role for Lp(a) in the pathogenesis of LV. Furthermore, a slight positive correlation between serum and tissue levels of Lp(a) was observed, despite previous publications in atherosclerotic vessels (macrocirculation) that found a significant correlation between serum and tissue levels of Lp(a), which can be explained by the fact that LV is a primarily localized disease rather than a systemic disease.…”

Relationship of lipoprotein-associated phospholipase A2 and oxidized low density lipoprotein in carotid atherosclerosis

“…This association suggested that the plasma levels of these analytes might be associated with their levels in atherosclerotic plaques. For example, we previously observed that the plasma level of the cardiovascular risk factor Lp[a] is associated with its levels in lesionbearing tissues, such as resected bypass vein grafts ( 38 ) and aortic aneurysms ( 39 ). In this study, however, the plasma levels of oxLDL are only borderline associated with carotid atheroma levels.…”

Circulating Markers of Abdominal Aortic Aneurysm Presence and Progression

“…A greater number of studies assessing the association of lipoprotein(a) with AAA were identified (Table III). These studies demonstrate higher concentrations of lipoprotein(a) in subjects with AAA compared to healthy controls but no difference from patients with atherothrombosis [56,68,83,87-89]. …”