Figure 5

Viral load, vascular lipid accumulation, and markers of endothelial activation. (a) Plasma viral loads for SIV-infected animals at 4 weeks after infection (4 weeks post) and killing. (b) Cranial abdominal aorta, SIV-positive animal. There is intense positive staining for lipid in intimal foam cells along with focally extensive lipid droplet accumulation in medial smooth muscle (Oil Red O). (c) Soluble VCAM-1 (sVCAM-1) levels were significantly higher in SIV-infected animals than in uninfected animals at the 4-week postinfection time point (P<0.01) and at the time of killing (P<0.05). 4 weeks pre, 4 weeks before virus inoculation of SIV-positive group; 4 weeks post, 4 weeks after virus inoculation of SIV-positive group; euthanasia, 9 weeks after virus inoculation of SIV-positive group. (d) The percent change in soluble E-selectin (sE-selectin) levels from baseline did not differ significantly between groups. 4 weeks pre, 4 weeks before virus inoculation of SIV-positive group; 4 weeks post, 4 weeks after virus inoculation of SIV-positive group; euthanasia, 9 weeks after virus inoculation of SIV-positive group. (e) Soluble ICAM-1 (sICAM-1) levels did not differ significantly between groups at any evaluated time point. 4 weeks pre, 4 weeks before virus inoculation of SIV-positive group; 4 weeks post, 4 weeks after virus inoculation of SIV-positive group; euthanasia, 9 weeks after virus inoculation of SIV-positive group. (f) Carotid bifurcation, SIV-positive animal. Granular cytoplasmic MCP-1 staining was present in a subset of endothelial cells in both SIV-positive and SIV-negative animals, as well as in scattered cells deeper within the intima. The percent of MCP-1+endothelial cells correlated significantly with scores based on American Heart Association lesion-type classification (P<0.03, R=0.455) and preinoculation levels of CRP (P=0.01, R=0.707) (MCP-1 immunohistochemistry with DAB chromogen and Mayer's hematoxylin counterstain). (g) Cranial abdominal aorta, SIV-negative animal. Many vessels showed strong, circumferentially discontinuous endothelial labeling for VCAM-1, but no significant correlations were identified between extent of endothelial VCAM-1 expression and measures of atherosclerotic lesion character or extent (VCAM-1 immunohistochemistry with DAB chromogen and Harris hematoxylin counterstain).