Abstract 275: Cholesterol Efflux Capacity is Inversely Associated with Severity of Carotid Atherosclerosis and Increases with Time Since Cerebrovascular Event
Introduction HDL is thought to exert its atheroprotective role by promoting cholesterol efflux from lipid-laden macrophages. Cholesterol efflux capacity (CEC) has been shown to be inversely associated with carotid intima-media thickness and presence of coronary artery disease. We assessed the hypothesis that CEC is associated with severity of carotid atherosclerosis and with cerebrovascular symptomatology.
Methods Symptomatic (n=114) and asymptomatic (n=41) patients with carotid stenosis were recruited from Vascular Surgery at the Royal Victoria and Jewish General hospitals, Montreal, Canada. Carotid Doppler ultrasound was performed and stenosis (50-79%, 80-99%) was graded according to velocities. Detailed information on symptomatology obtained. A blood sample was collected on the day of the ultrasound; HDL was obtained by polyethylene glycol precipitation after depletion of apoB-containing lipoproteins. CEC was determined by incubating HDL in cAMP-stimulated J774 mouse peritoneal macrophages for 6 hours. Specific cholesterol efflux was obtained by subtracting total efflux from efflux in non-cAMP stimulated cells. Differences in CEC were assessed using linear regression according to 1) stenosis, 2) symotomatology and, 3) timing of symptomatology.
Results Compared to patients with 50-79% stenosis (n=31), patients with 80-99% stenosis (n=124) had significantly decreased CEC (beta=-2.23, P=0.04) after adjustment for age, sex, apoAI, and systolic BP. CEC was not significantly different between symptomatic or asymptomatic patients. However, in symptomatic patients CEC increased with increasing time since cerebrovascular event. Specifically, compared to 0-30 days (n=72), CEC was non-significantly increased 31-90 days since event (n=31, beta=1.64, P=NS), while increased significantly ≥ 90 days since event (n=11, beta=4.48, P=0.01), after adjustment as described above.
Conclusion These results suggest that CEC is inversely associated with severity of carotid stenosis and that CEC increases with increasing time since symptomatic event. This may be related to remodeling of HDL during the acute phase reaction after a recent ischemic event.
- © 2013 by American Heart Association, Inc.