Arterioscler Thromb Vasc Biol Effects of Aspirin on Clot Structure and Fibrinolysis Using a Novel In Vitro Cellular System by R.A. Ajjan, K.F. Standeven, M. Khanbhai, F. Phoenix, K.C. Gersh, J.W. Weisel, M.T. Kearney, R.A.S. Ariëns, and P.J. Grant Arterioscler Thromb Vasc Biol Volume 29(5):712-717 May 1, 2009 Copyright © American Heart Association, Inc. All rights reserved.

Figure 1. A, Fibrinogen purified from aspirin-treated media had increased final turbidity, suggesting the formation of thicker fibers. Figure 1. A, Fibrinogen purified from aspirin-treated media had increased final turbidity, suggesting the formation of thicker fibers. B, Lag phase was increased in clots made from aspirin compared with nontreated fibrinogen. C, Increase in lag phase in aspirin-treated clots was more pronounced when lower thrombin concentrations were used. R.A. Ajjan et al. Arterioscler Thromb Vasc Biol. 2009;29:712-717 Copyright © American Heart Association, Inc. All rights reserved.

Figure 2. Macroscopic fibrinolysis before (A) and after (B) correcting data for maximum absorbance. Figure 2. Macroscopic fibrinolysis before (A) and after (B) correcting data for maximum absorbance. C, Microscopic fibrinolysis observed in real time using laser scanning confocal microscopy. Scale bars on micrographs indicate 5 μm. R.A. Ajjan et al. Arterioscler Thromb Vasc Biol. 2009;29:712-717 Copyright © American Heart Association, Inc. All rights reserved.

Figure 3. Scanning electron micrographs (EM) of clots made from recombinant fibrinogen. Figure 3. Scanning electron micrographs (EM) of clots made from recombinant fibrinogen. Panels A and B represent EM of clots prepared from recombinant fibrinogen purified from media not containing aspirin (0 mg l−1) or containing this agent (100 mg l−1). Scale bars on all micrographs indicate 5 μm (magnification of 10 000×). R.A. Ajjan et al. Arterioscler Thromb Vasc Biol. 2009;29:712-717 Copyright © American Heart Association, Inc. All rights reserved.

Figure 4. Detection of fibrinogen acetylation using monoclonal acetyl-lysine antibody. Figure 4. Detection of fibrinogen acetylation using monoclonal acetyl-lysine antibody. Asp− and Asp+ represent fibrinogen purified from nonaspirin and aspirin-treated media at (100 mg l−1), respectively. A band of ≈68 kDa was detected, suggesting acetylation of lysine residues in the α-chain of fibrinogen. R.A. Ajjan et al. Arterioscler Thromb Vasc Biol. 2009;29:712-717 Copyright © American Heart Association, Inc. All rights reserved.

Figure 5. Changes in clot structure using plasma-purified fibrinogen from 3 healthy volunteers before and after 1 week of aspirin treatment (150 mg/d). Figure 5. Changes in clot structure using plasma-purified fibrinogen from 3 healthy volunteers before and after 1 week of aspirin treatment (150 mg/d). A, Percentage change in final turbidity (FT) and time to 50% lysis (LT) before and after aspirin treatment. B, Electron microscopy of a clot made from 1 volunteer before and after aspirin treatment (B and C, respectively). R.A. Ajjan et al. Arterioscler Thromb Vasc Biol. 2009;29:712-717 Copyright © American Heart Association, Inc. All rights reserved.