Endothelial ICAM-1 expression associated with inflammatory cell response in human ischemic stroke.
BACKGROUND
After focal brain ischemia, leukocytes adhere to the perturbed endothelium and are believed to aggravate reperfusion injury. Although ischemia-induced upregulation of endothelial adhesion molecules, intercellular adhesion molecule-1 (ICAM-1) and P-selectin, has been observed in experimental animals, the mechanism of cerebral leukocyte infiltration and thus therapeutic possibilities to reduce it in humans are uncertain.


RESULTS
We counted the granulocytes, mononuclear phagocytes, and the percentages of cerebral microvessels expressing ICAM-1 by applying immunohistochemistry on brain sections showing a variable degree of neuronal damage from 11 human subjects who died 15 hours to 18 days after ischemic stroke and from normal control brains. In infarcted regions, granulocytes were detected as early as at 15 hours after injury (11.3 versus 0.5 cells/mm2 in noninfarcted hemisphere); their amount exceeded 200 cells/mm2 by 2.2 days but was back to normal level at 6.3 and 8.5 days. Acute infarctions (0.6 to 8.5 days) harbored significantly more ICAM-1-stained microvessels (up to 97% of microvessels at 1.8 days) than the noninfarcted hemisphere (P < .001), although the noninfarcted hemisphere (1.8 to 6.3 days) also showed higher ICAM-1 expression than controls. In the absence of ICAM-1 upregulation, macrophages (> 200/mm2) were abundant in the core of neuronal damage at 17 and 18 days.


CONCLUSIONS
The striking upregulation of endothelial ICAM-1 expression, functioning in concert with chemotactic factors, may cause granulocyte infiltration during the first 3 days after stroke. This study may support the usage and timing of antibody infusions to block endothelial adhesion molecules in an attempt to reduce leukocyte-induced damage in stroke.
Lindsberg
P J
PJ
Department of Neurology, University of Helsinki, Finland.
Carpén
O
O
Paetau
A
A
Karjalainen-Lindsberg
M L
ML
Kaste
M
M
D000328:Adult; D000368:Aged; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000032:analysis; D004730:Endothelium, Vascular / Q000737:chemistry*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis*; D007962:Leukocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D019408:Platelet Endothelial Cell Adhesion Molecule-1
D015214:Antigens, Differentiation, Myelomonocytic; D015815:Cell Adhesion Molecules; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1