http://stroke.ahajournals.org/content/44/7/1988.abstract
Abstract
Background and Purpose—Our aim was to assess the spatiotemporal evolution of the cerebrovascular inflammation occurring after ischemic and hemorrhagic
strokes using a recently developed, fast, and ultra-sensitive molecular MRI method.
Methods—We first
assessed longitudinally the cerebrovascular inflammation triggered by
collagenase-induced hemorrhage and by permanent/transient
middle cerebral artery occlusion in mice,
using MRI after injection of microparticles of iron oxide targeted to
vascular cell
adhesion molecule-1 (MPIOs-αVCAM-1).
Thereafter, we used this method to study the anti-inflammatory effects
of celecoxib,
atorvastatin, and dipyridamole after stroke.
Results—Using
multiparametric MRI, we demonstrated that the level and the kinetics of
cerebrovascular VCAM-1 expression depend on
several parameters, including stroke
pathogenesis, the natural history of the disease, and the administration
of inflammation-modulating
drugs. Interestingly, in transient middle
cerebral artery occlusion and intracranial hemorrhage models, VCAM-1
expression
was maximal at 24 hours and almost returned
to baseline 5 days after stroke onset. In contrast, after permanent
middle cerebral
artery occlusion, VCAM-1 overexpression was
sustained between 24 hours and 5 days, and was particularly significant
in the
peri-infarct areas. Our results suggest that
these perilesional areas expressing VCAM-1 constitute an inflammatory
penumbra
that is recruited by the ischemic core during
the subacute phase. Using MPIOs-αVCAM-1–enhanced imaging, we also
provided evidence
that celecoxib and atorvastatin (but not
dipyridamole) alleviate VCAM-1 overexpression after stroke and prevent
formation
of the inflammatory penumbra.
Conclusions—MPIOs-αVCAM-1–enhanced imaging seems to be promising in the detection of individuals presenting with severe cerebrovascular
responses after stroke, which could therefore benefit from anti-inflammatory treatments.
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