Figure 1: Endothelial and Monocytic Activation by Platelets Is Enhanced in HIV Subjects

(A) Immunofluorescence microscopy of platelet adhesion to HUVECs in healthy and HIV subjects. Freshly isolated platelets (green) from controls (C) and HIV subjects (HIV) were stained with CellTracker dye and left untreated (Basal, left panels) or treated with thrombin (0.05 U/ml for 5 min; Activated, right panels) before incubating with HUVECs. HUVEC nuclei are stained with DAPI (blue). The images are representative of 3 subjects for each group. Magnification, 20×. **p < 0.01. (B to D) HUVECs were coincubated with resting (Basal) or activated platelets from HIV (n = 6 to 7) and healthy controls (n = 6 to 7) for 2 h. Interleukin (IL)-8 (B), intercellular adhesion molecule (ICAM)-1 (C), and monocyte chemotactic protein (MCP)-1 (D) expression was assessed by quantitative polymerase chain reaction (qPCR). Values, normalized on 18S5 RNA represent fold change versus respective control. TNF (10 ng/ml) represents the positive control. *p < 0.05. (E and F) THP-1 were cultured with HIV platelets (HIV, n = 7) or control platelets (C, n = 4) at basal (Basal) or after stimulation (thrombin 0.25 U/ml, 5 min) for 2 h. MCP-1 (E) and IL-6 (F) expression was assessed by qPCR and normalized on 18S5 RNA. Lipopolysaccharide (100 ng/ml) was used as positive control. Values represent fold increase versus respective control. *p < 0.01, **p < 0.05, and p = 0.07. HIV = human immunodeficiency virus; HUVEC = human umbilical vein endothelial cell.



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