[Metalloproteinase in carotid endarterectomy plaques: increased activity in critical stenosis zones].
BACKGROUND
The presence of metalloproteinases in atherosclerotic plaques has been described but their role is not well understood. An increased secretion of these proteolytic enzymes could explain plaque instability and distal embolization.


OBJECTIVE
To measure metalloproteinase activity in atherosclerotic plaques obtained after carotid endarterectomy.


METHODS
Plaques were divided in one segment with and one segment without stenosis, the latter being used as control. Both segments were incubated in culture media for 48 h or were fixed for histology. The conditioned medium was studied using gelatin zimography and digital densitometry. Metalloproteinases were identified by their molecular weight, inhibition with EDTA or Western Blot. Standard histologic study and immunohistochemistry were done.


RESULTS
In stenotic areas, metalloproteinase 9 (92kD) secretion was 260% higher than in regular plaques (191 and 73 Kilopixels/microgram protein respectively p < 0.02). The histological study of stenotic areas showed macrophage infiltration and neoformation of blood vessels.


CONCLUSIONS
The increased secretion of cellular matrix degrading enzyme metalloproteinase 9 in stenotic areas of atherosclerotic plaques, could explain plaque instability and subsequent embolization.
Mertens
R
R
Departamento de Enfermedades Cardiovasculares, Facultad de Medicina, P Universidad Católica de Chile, Santiago de Chile.
Valdés
F
F
Krämer
A
A
Guarda
E
E
Acevedo
C
C
Vergara
T
T
D001161:Arteriosclerosis / Q000201:enzymology*; D002343:Carotid Artery, Internal / Q000201:enzymology; D016893:Carotid Stenosis / Q000201:enzymology*; D003720:Densitometry; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007150:Immunohistochemistry; D008666:Metalloendopeptidases / Q000378:metabolism*
D008666:Metalloendopeptidases
Metaloproteinasas en placas de endarterectomía carotídea: actividad aumentada en áreas de estenosis crítica.