Platelets
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Biography Historical Article
Gustav Born: pioneer in imaging platelet and leukocyte biology.
Gustav Born achieved scientific fame for his application of light transmission aggregometry to the study of platelet function, but also led interdisciplinary research teams in pioneering quantitative in vivo imaging studies of platelet aggregation and leukocyte adhesion, and in conducting the first research into the biomechanical factors underlying atherosclerotic plaque rupture. Gus Born also communicated both current research findings and an integrated understanding of cardiovascular biology to a wide audience through acting as scientific advisor on several television productions. Using footage from two of these films, we discuss Gustav Born's scientific achievements and legacy.
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Numerous number of evidences show that high on-treatment platelet reactivity is a well-known risk factor for adverse events in patients after percutaneous coronary intervention (PCI). Controversial situations still exist regarding the effectiveness of tailoring antiplatelet therapy according to platelet function monitoring. The PubMed, Embase, and Cochrane Central databases were searched for randomized trials comparing platelet reactivity-adjusted antiplatelet therapy with conventional antiplatelet therapy in patients undergoing PCI. ⋯ Six studies enrolling 6347 patients were included. Compared with conventional treatment, tailoring antiplatelet failed to reduce all-cause mortality (RR: 0.89, 95% confidence interval [CI]: 0.63-1.24, P = 0.48), MACE (RR: 1.02, 95% CI: 0.92-1.14, P = 0.69), MI (RR: 1.07, 95% CI: 0.95-1.21, P = 0.24), CV death (RR: 0.69, 95% CI: 0.40-1.19, P = 0.09), ST (RR: 0.83, 95% CI: 0.50-1.38, P = 0.23), stroke or TIA (RR: 1.08, 95% CI: 0.55-2.12, P = 0.83), revascularization (RR: 0.96, 95% CI: 0.69-1.33, P = 0.79), and major bleeding events (RR: 0.79, 95% CI: 0.53-1.17, P = 0.24). Compared with traditional antiplatelet treatment, tailoring antiplatelet therapy according to platelet reactivity testing failed to reduce all-cause mortality, MACE, and major bleeding events in patients undergoing PCI.
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Pneumatic tube is an attractive way to transport blood samples from the emergency department to the central laboratory facility. We aimed to investigate the impact of pneumatic tube transportation on blood samples for analysis of whole blood coagulation and platelet function. We included 21 healthy adult individuals and measured global coagulation assays by rotational thromboelastometry (ROTEM) and platelet aggregation induced by arachidonic acid (AA) and adenosine diphosphate (ADP) using impedance aggregometry (ROTEM Platelet), on samples transported manually or by pneumatic tube transport. ⋯ Our data revealed no difference in the far majority of ROTEM parameters (P > 0.003), while significantly decreased values were observed for INTEM clotting time (CT) (P = 0.002) and maximum clot firmness (MCF) including the amplitude after 10 min (A10) (P < 0.0001). No statistically significant difference was observed on impedance aggregometry results when manual transport was compared to pneumatic tube transport (P > 0.003). This study indicates that only minor and unsystematic differences between manual transport and pneumatic tube transport may be observed in ROTEM analyses, and that there is no influence from pneumatic tube transport on impedance aggregometry analyses using AA and ADP.
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Smokers receiving clopidogrel show a lower residual platelet reactivity than non-smokers, a phenomenon generally ascribed to smoking-induced increased production of clopidogrel active metabolite, but also associated with the high hemoglobin levels of smokers, which decreases platelet reactivity in tests that measure platelet function in whole blood. We evaluated the impact of cigarette smoking and of hemoglobin levels on platelet reactivity index (PRI) measured by the vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) assay in whole blood samples from patients with non-ST elevation acute coronary syndrome (NSTE-ACS) undergoing percutaneous coronary interventions, both before and after clopidogrel administration. PRI was measured in 718 clopidogrel-naïve NSTE-ACS patients, both before and 1 month after treatment with clopidogrel (75 mg daily). ⋯ Our analysis confirms that clopidogrel-treated smokers have lower platelet reactivity, measured by the VASP-P assay, compared to clopidogrel-treated non-smokers. However, smokers had lower platelet reactivity already before receiving clopidogrel treatment, suggesting that smoke affects platelet reactivity independently of its potential effect on the pharmacokinetics of clopidogrel. Our data also indicate that such an effect is not mediated by increased hemoglobin levels.
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Platelet-rich fibrin (PRF) is generated from the patients' own venous blood by a single centrifugation step without the additional use of anticoagulants. Based on the previously described LSCC (low-speed centrifugation concept), our group showed that modification of the centrifugation setting, that is, reducing the relative centrifugal force (RCF) and mildly increasing the centrifugation time, resulted in modified solid and liquid PRF-matrices with increased number of platelets, leukocytes, and growth factors' concentrations. The aim of this study was to determine whether RCF reduction might also result in different tissue reactions toward the two PRF-based matrices, especially vascularization and cell distribution in vivo. ⋯ By contrast, PRF-medium was more porous, had a significantly higher in vivo vascularization rate, and included significantly more human cells, especially at day 10, compared to PRF-high. These findings highlight the possibility of modifying the structure and composition of PRF matrices and thus selectively altering their regenerative potential in vivo. Clinical studies now must evaluate the different PRF matrices for bone and soft-tissue regeneration to validate possible benefits using personalized preparation protocols.