Novel Antiplatelet Agents in Cardiovascular Medicine

In silico identification of new inhibitors for βeta-2-glycoprotein I as a major antigen in antiphospholipid antibody syndrome

Beta 2 glycoprotein I (β2GPI) is a major antigen for autoantibodies present in antiphospholipid antibody syndrome (APS). β2GPI is a single polypeptide with five repeated domains and different conformations. The activated J-shaped conformation of β2GPI binds to negatively charged phospholipids in the membrane via the fifth domain and causes blood clotting reactions. We applied a drug repurposing strategy using virtual screening and molecular dynamics to find the best FDA drugs against the fifth domain of β2GPI. In the first phase, FDA drugs that had the most favorable ΔG with the fifth domain of β2GPI were selected by virtual screening. Among these drugs that had the most favorable ΔG, Vorapaxar and Antrafenine were selected for molecular dynamics (MD) simulation studies. MD simulation was performed to evaluate the stability of Vorapaxar and Antrafenine complexes and the effect of the two drugs on protein conformation. Also, MD simulation was done to investigate the effect of Antrafenine and Vorapaxar on the binding of β2GPI to the platelet model membrane. According to the results, Vorapaxar and Antrafenine were bound to the protein with the favorable binding energy (Vorapaxar and Antrafenine binding energies are - 49.641 and - 38.803 kcal/mol, respectively). In this study, it was shown that unlike protein alone and protein in the Antrafenine complex, the protein in the Vorapaxar complex was completely separated from the model membrane after 350 ns. Moreover, Vorapaxar led to more changes in the activated J-shape of β2GPI. Thus, Vorapaxar can be a suitable candidate for further investigations on the treatment of APS.

DAPT Plus Cilostazol is Better Than Traditional DAPT or Aspirin Plus Ticagrelor as Elective PCI for Intermediate-to-Highly Complex Cases: Prospective, Randomized, PRU-Based Study in Taiwan

PURPOSE

Current treatment guidelines do not recommend different antiplatelet treatments for patients in different coronary risk categories; nor do they consider ethnic differences in responses to individual drugs.

OBJECTIVES

We performed a prospective, single-blind, randomized, comparative study of Taiwanese patients with stable angina and scheduled stent implantation for intermediate-to-highly complex coronary lesions and compared the platelet reactivity unit (PRU) levels and 24-month outcomes of groups receiving three different antiplatelet treatments.

METHODS

Patients (N = 334) were randomized into three treatment groups (aspirin + clopidogrel, aspirin + ticagrelor, or aspirin + clopidogrel + cilostazol) for 6 months of treatment and were then switched to aspirin only. PRU levels were determined 24 h, 7 days, and 1 month after stent implantation. Clinical outcomes and adverse events were recorded over 24 months.

RESULTS

Clopidogrel treatment reached full effect after 1 month. Ticagrelor decreased PRU levels more than did clopidogrel but often to levels that increased the risk of hemorrhage. The addition of cilostazol to clopidogrel decreased PRU levels earlier and more strongly than clopidogrel alone but not as strongly as did ticagrelor. Ticagrelor treatment caused fewer major adverse cardiovascular events (MACEs) and more episodes of minor bleeding than the other two treatments.

CONCLUSIONS

Clopidogrel appears safer than ticagrelor in Taiwanese patients with stable angina after stent implantation for intermediate-to-highly complex coronary lesions. The addition of cilostazol to clopidogrel may provide a more rapid decrease in PRU to therapeutic levels without increasing the risk of hemorrhage.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02101411.