Abstract 12120: Differential Association of Serum Amyloid A and Pentraxin-3 with Allele-Specific Lipoprotein(a) Levels in a Bi-ethnic Population
Introduction: The role of inflammation in the pathogenesis of atherosclerotic cardiovascular disease (CVD) is well recognized, although underlying mechanisms are not completely understood. Lipoprotein(a) (Lp(a)) has been implicated as a CVD risk factor and levels differ across ethnicities. Studies suggest that systemic and vascular inflammation impacts on Lp(a) level, synergistically increasing the risk for CVD, as well as contributing to its well-known interethnic difference.
Objective: We investigated the effect of systemic (serum amyloid A, SAA) and vascular (pentraxin-3, PTX-3) inflammation on Lp(a) and allele-specific apo(a) levels in a bi-ethnic population.
Methods: Lp(a) and allele-specific apo(a) levels, apo(a) sizes, SAA and PTX-3 levels were determined in 258 Caucasians and 163 African Americans.
Results: We dichotomized study subjects into two groups using the respective median SAA (29.8 mg/dl for Caucasians and 41.5 mg/dl for African Americans) or PTX-3 (1.56 ng/ml for Caucasians and 1.09 ng/ml for African Americans) levels. Among African Americans, Lp(a) levels were significantly increased (146 vs. 117 nmol/L, P=0.024) in the high compared to low SAA group, whereas no difference was seen across PTX-3 groups. Among Caucasians, there were no significant associations between Lp(a) and SAA or PTX-3 levels. Further, among African Americans with smaller (<26K4) apo(a) sizes, subjects in the high SAA group had higher allele-specific apo(a) levels (111 vs. 79 nmol/L, P=0.020) compared to subjects in the low SAA group. Again, no difference was seen for PTX-3. We did not find any significant associations between allele-specific apo(a) and SAA or PTX-3 levels among Caucasians with smaller (<26K4) apo(a) sizes.
Conclusion: Elevated levels of SAA, but not PTX-3, are significantly associated with higher Lp(a) levels for smaller (<26K4) apo(a) sizes in African Americans. Our results implicate that a pro-inflammatory stimulus may result in a selective increase in Lp(a) levels among African Americans carrying smaller apo(a) size, which might contribute to the interethnic difference in allele-specific Lp(a) levels.
- © 2010 by American Heart Association, Inc.