Differences in lesion severity and cellular composition between in vivo assessed upstream and downstream sides of human symptomatic carotid atherosclerotic plaques.
BACKGROUND
The heterogeneous structure of carotid atherosclerotic plaques may be better understood if it is related to blood flow variations, influencing gene expression and cellular functions. Upstream of the maximum stenosis there is laminar blood flow and high shear stress, downstream there is turbulence and low shear stress. We studied if these variations were associated with differences in plaque morphology and composition between sites located up- and downstream of the maximum stenosis in symptomatic carotid plaques.


METHODS
Patients with symptomatic carotid stenosis were examined with magnetic resonance angiography to localize the maximum stenosis in-vivo, prior to endarterectomy. In 41 endarterectomized specimens, transverse tissue sections prepared up- and downstream of the maximum stenosis were compared using histopathology and immunohistochemistry.


RESULTS
The location of maximum stenosis relative the carotid bifurcation varied considerably between plaques. Compared with the downstream side, the upstream side of the stenosis had higher incidence of severe lesions with cap rupture and intraplaque hemorrhage, more macrophages, less smooth muscle cells and more collagen.


CONCLUSIONS
The up- and downstream sides of symptomatic carotid plaques differed in plaque morphology and composition. This implies that the intraplaque location of sampling sites may be a confounding factor in studies of atherosclerotic plaques.
Fagerberg
Björn
B
Sahlgrenska Center for Cardiovascular and Metabolic Research, University of Gothenburg, Gothenburg, Sweden.
Ryndel
Mikael
M
Kjelldahl
Josefin
J
Akyürek
Levent M
LM
Rosengren
Lars
L
Karlström
Lars
L
Bergström
Göran
G
Olson
Fredrik J
FJ
D000368:Aged; D000369:Aged, 80 and over; D002339:Carotid Arteries / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D003094:Collagen / Q000032:analysis; D016894:Endarterectomy, Carotid; D005260:Female; D005355:Fibrosis; D006470:Hemorrhage / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008264:Macrophages / Q000473:pathology; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D012039:Regional Blood Flow; D012421:Rupture; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color
D003094:Collagen