Endothelial apoptosis does not determine symptom status in carotid artery disease.
BACKGROUND
We examined the hypothesis that endothelial denudation in advanced carotid plaques (CPs) occurs by increased apoptosis of endothelial cells (ECs) using scanning electron microscopy (SEM) as well as markers of cellular proliferation and apoptosis in advanced symptomatic CPs (SCPs) and asymptomatic CPs (ACPs).


METHODS
93 consecutive patients underwent carotid endarterectomy. Five additional specimens were studied by SEM. We performed TUNEL assays, and immunostaining against Fas receptor (FasR), Fas ligand (FasL), activated caspase 3 (ACA3) and Ki-67.


RESULTS
SEM revealed morphological changes consistent with EC detachment. Surprisingly, ACA3 positivity was more pronounced on the endothelium of ACPs (4.6 +/- 0.7% of total EC count) than on SCPs (3.3 +/- 0.7%, p = 0.049), and was found to correlate positively with nuclear Ki-67 expression (r(s) = 0.275, p = 0.040). FasL expression was significantly increased on the endothelium of SCPs compared with ACPs (66.4 +/- 4.4 vs. 53.9 +/- 4.5%, p = 0.047).


CONCLUSIONS
Absence of increased positivity of apoptotic markers dismisses apoptosis as a dominant mechanism underlying endothelial detachment of SCPs. Rather, increased ACA3 with co-expression of Ki-67 in ACPs might suggest that renewal of endothelium by active cell turnover may contribute to clinically silent evolution of plaques with preserved EC integrity. These observations may assist in designing novel therapies to prevent endothelial decay and symptom generation in advanced carotid artery disease.
Nuotio
Krista
K
Neuroscience Program, Biomedicum Helsinki, Helsinki, Finland. Krista.Nuotio@helsinki.fi
Mäyränpää
Mikko I
MI
Saksi
Jani
J
Ijas
Petra
P
Sairanen
Tiina
T
Carpén
Olli
O
Soinne
Lauri
L
Saimanen
Eija
E
Salonen
Oili
O
Lepäntalo
Mauri
M
Kovanen
Petri T
PT
Kaste
Markku
M
Lindsberg
Perttu J
PJ
D000368:Aged; D017209:Apoptosis; D002343:Carotid Artery, Internal / Q000201:enzymology / Q000276:immunology / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D016893:Carotid Stenosis / Q000201:enzymology / Q000276:immunology / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D053148:Caspase 3 / Q000032:analysis; D002448:Cell Adhesion; D016894:Endarterectomy, Carotid; D004730:Endothelium, Vascular / Q000201:enzymology / Q000276:immunology / Q000503:physiopathology* / Q000648:ultrastructure; D053222:Fas Ligand Protein / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D012307:Risk Factors; D012720:Severity of Illness Index; D019014:fas Receptor / Q000032:analysis
D053222:Fas Ligand Protein; D019394:Ki-67 Antigen; D019014:fas Receptor; D053148:Caspase 3