Platelets
-
Platelets of patients with sickle cell disease (SCD) show evidence of mild activation in the non-crisis steady state and greater activation during vaso-occlusive crises (VOC). Prasugrel, a potent inhibitor of ADP-mediated platelet activation and aggregation, may be useful in attenuating VOC. We compared platelet responses to ADP stimulation in patients with SCD and healthy subjects before and after treatment with prasugrel. ⋯ Furthermore, prasugrel decreases ex vivo ADP-stimulated platelet aggregation with monocytes and neutrophils as measured by the monocyte-platelet and neutrophil-platelet aggregate MFI. This implies that in the presence of prasugrel, fewer platelets adhere to monocytes and neutrophils, which may result in reducing cell-platelet aggregate size. Therefore, reduced platelet reactivity and decreased size of leukocyte-platelet aggregates suggest additional mechanisms by which prasugrel may provide benefit to patients with SCD and support further investigation of possible therapeutic benefits of prasugrel in this population.
-
Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by chronically low peripheral blood platelet counts. Eltrombopag is an oral, non-peptide, thrombopoietin-receptor agonist that increases platelet production. This report examines peri-procedural platelet counts and bleeding complications among chronic ITP patients requiring dental procedures while participating in clinical studies with eltrombopag. ⋯ Among patients with chronic ITP who required a dental procedure during clinical studies of eltrombopag, supplemental ITP treatment was required for both patients who received placebo but was not required for most patients who received eltrombopag. No bleeding complications were reported. These data imply that patients with chronic ITP who receive eltrombopag and experience increases in platelet counts fulfill current pre-procedural platelet count recommendations to undergo invasive dental procedures, and may have a lower risk of bleeding complications and a reduced need for supplemental ITP treatment.
-
Storage impairs platelet function. It was hypothesized that multiple electrode aggregometry in vitro could be used to follow aggregability in platelet concentrates over time and that the results predict the efficacy of platelet transfusion in an ex vivo transfusion model. In vitro platelet aggregability was assessed in apheresis and pooled buffy coat platelet concentrates (BCs) (n = 13 each) using multiple electrode aggregometry with different agonists 1, 3, 5 and 7 days after preparation. ⋯ The same pattern was observed after ex vivo addition of apheresis and pooled BCs to whole blood samples. The best correlation between in vitro aggregability and changes in aggregation after addition was achieved with collagen as agonist (r = 0.67, p < 0.001). In conclusion, multiple electrode aggregometry can be used to follow aggregability in platelet concentrates in vitro, and the results predict with moderate accuracy changes in aggregation after addition of platelet concentrate to whole blood samples.
-
Previous laboratory and clinical data have shown evidence for the concept of rebalanced hemostasis in liver disease. We evaluate whether this concept of rebalanced hemostasis can be applied in patients with idiopathic thrombocytopenic purpura (ITP). Twenty patients with ITP (platelet count < 100 × 10(9) /l) who visited our hospital were enrolled. ⋯ We found that the vWF antigen level was elevated and the TEG profiles were better in older ITP patients with longer disease statuses. Patients with ITP appeared to achieve a rebalance hemostasis through an elevation of their plasma vWF antigen levels and hemostatic changes that promote thrombosis. Measuring the vWF antigen levels and performing TEG analysis can help determine the treatment strategy in ITP patients.