Info

Allb, ß3

Fibrinogen, fibronectin, vitronectin

aIV ß3

Vitronectin, fibrinogen, thrombospondin

VLA, very late antigens; ICAM, intercellular adhesion molecule; VCAM, vascular cell adhesion molecule.

important role in the transmigration of leukocytes. The cytokines TNF-a, IL-1, and IFN-y stimulate the expression of ICAM on the vascular endothelial surface. Endothelial VCAM-1 supports the adhesion of lymphocytes, monocytes, eosinophils, and basophils. Platelet endothelial cell adhesion molecule (PECAM-1) exists on platelets, T lymphocytes, and monocytes, suggesting that it contributes to leukocyte migration and thrombosis (Table 7).

Cadhesions represent a group of proteins whose major function is the maintenance of tight gap junctions and intercellular spacing within the vascular endothelium.

Proteoglycans constitute a large protein family with glycoaminoglycan side chains that mediate lymphocyte binding and epithelial cell binding to collagen, fibronectin, and thrombospondin. The glycoprotein Ib/IX complex is the most well-known cell adhesion molecule of the mucin family. It contains a thrombin binding site and a von Willebrand factor binding site.

Cytokines and Provoked Inflammatory Responses

Histologic studies have shown that atherosclerotic plaques contain foci of monocytes, macrophages, and activated lymphocytes. The cytokine secretory capacity of monocytes expressing TNF, IL-1, IL-6, and IFN-k is also increased. The acute-phase reactants CRP and amyloid A protein are elevated in a majority of patients with unstable angina and identify those patients who were more likely to suffer an in-hospital ischemic-thrombotic event (116). The prognostic value of fibrinogen, an acute phase protein directly involved with the cascade of events leading to thrombosis, has also been determined in patients with unstable angina and non-ST-segment elevation MI in whom elevations identify increased risk of spontaneous ischemia, MI, and death (117) (Table 8).

Table 6

Selectins: Cellular Distribution and Interactions

Table 6

Selectins: Cellular Distribution and Interactions

Cell

Distribution Binding site

L-Selectin E-Selectin P-Selectin

All leukocytes Endothelial cells Activated endothelial cells Neutrophils, monocytes, T lymphocytes Platelets, endothelial cells Neutrophils, monocytes, T lymphocytes (Weibel-Palade)

Table 7 Adhesion Molecules

Glycoprotein

Distribution

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