88
LDL DENSITY SIGNIFICANTLY PREDICTS CAROTID PLAQUE
CELL COMPOSITION AND PREVALENCE OF
CEREBROVASCULAR EVENTS IN PATIENTS WITH SEVERE
CAROTID STENOSIS
A. Zambon, S. Bertocco, E. Faggin, N. Vitturi, M. Puato, A.C. Pessina,
G. Crepaldi, P. Pauletto
University of Padova, Italy
LDL size and density significantly contribute to LDL atherogenicity. Small,
dense LDL particles are associated with an increased risk of coronary artery
disease, and with an increased carotid intima-media thickness. We
investigated the possible association between LDL density, cell composition
of carotid plaques and the occurrence of ischemic cerebrovascular events
(ICVE) in 68 patients with severe carotid stenosis undergoing carotid
endarterectomy. LDL density was evaluated by density gradient
ultracentrifugation. Endarterectomy specimens were examined by
immunocytochemistry using the following monoclonal antibodies: i) SM-E7
for smooth muscle cells (SMCs), ii) the anti-macrophage HAM 56, and iii)
the anti-lymphocyte CD45R0. Fifty patients had an ICVE prior the
endarterectomy, 18 had no ICVE. Blood pressure, gender, BMI, total, LDL
and HDL cholesterol, TG, Lp(a), apo AI and apo B levels, smoke habits,
glucose, fibrinogen and plasminogen plasma levels, were similar in patients
with and without previous ICVE. Patients with previous ICVE had
significantly denser LDL particles (p<0.01) and more plaque macrophages
(p=0.01) than those with no ICVE. Small, dense LDL were associated with
increased number of macrophages (r= 0.59, p<0.01) and less SMCs (r= -
0.50, p<0.01) in the plaque. In a multivariate analysis LDL density was the
strongest predictor of the number of macrophages in the plaque (p=0.01). In
a logistic regression analysis the number of macrophages strongly predicted
the prevalence of ICVE (p<0.01). The presence of dense LDL particles is
associated with an abundance of inflammatory cells in the carotid plaque
(unstable plaque) and excess prevalence of ICVE in subjects with carotid
stenosis.