Effects of Crushed Ticagrelor Versus Eptifibatide Bolus Plus Clopidogrel in Troponin-Negative Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention: A Randomized Clinical Trial.

Background After a loading dose of ticagrelor, the rate of high on-treatment platelet reactivity remains elevated, which increases periprocedural myocardial infarction and injury. This indicates that faster platelet inhibition with crushed ticagrelor (CTIC) or eptifibatide is needed to reduce high on-treatment platelet reactivity. The efficacy of CTIC versus eptifibatide bolus plus clopidogrel is unknown. Methods and Results A total of 100 P2Y12 naïve, troponin-negative patients with acute coronary syndrome were randomized to CTIC (180 mg) versus eptifibatide bolus (180 µg/kg×2 intravenous boluses) plus clopidogrel (600 mg) at the time of percutaneous coronary intervention. High on-treatment platelet reactivity was markedly higher with CTIC versus eptifibatide bolus plus clopidogrel (42% versus 0%; P<0.001) at 30 minutes and persisted up to 2 hours (12% versus 0%; P=0.01, respectively). Platelet aggregation by adenosine diphosphate dropped faster from baseline with eptifibatide bolus plus clopidogrel versus CTIC (0.5 versus 2 hours, respectively) and was higher with CTIC versus eptifibatide bolus plus clopidogrel at 0.5, 2, and 4 hours after loading dose (53±12% versus 1.3±2%; 35±11% versus 0.34±1.0%; and 23±9% versus 3.5±2%, respectively; P<0.001). Eptifibatide bolus plus clopidogrel, but not CTIC, significantly inhibited platelet aggregation induced by thrombin-receptor activating peptide. Periprocedural myocardial infarction and injury was higher with CTIC versus eptifibatide bolus plus clopidogrel (48% versus 28%, respectively; P=0.035). Post-percutaneous coronary intervention hemoglobin levels were not different between groups. Conclusions Eptifibatide bolus plus clopidogrel led to faster and more potent platelet inhibition than CTIC and reduced periprocedural myocardial infarction and injury in troponin-negative acute coronary syndrome patients undergoing percutaneous coronary intervention, with no significant hemoglobin drop after percutaneous coronary intervention. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02925923.

Plasma membrane Ca-ATPase isoform expression in human cataractous lenses compared to age-matched clear lenses.

The plasma membrane calcium ATPase (PMCA) pump is the major mechanism by which calcium is removed from the lens. The aim of this study was to determine if mRNA and proteins levels of PMCA isoforms changed with age or lens opacity. mRNA was quantified using a quantitative real-time reverse transcription polymerase chain reaction assay (RT-PCR). PMCA protein levels were quantified using Western blot analysis. No PMCA mRNA or proteins were detected in human lens fiber cells. The mRNA and protein levels of PMCA1, 3 and 4 in the epithelium of cataractous lenses were similar to those of epithelium from age-matched clear lenses and were also the same in younger lenses. PMCA2 mRNA and protein levels were 1.6-2.5 times higher, respectively, in cataractous lenses compared to age-matched clear lenses. Elevated PMCA2 expression in cataractous lenses might be a compensatory mechanism to overcome higher intracellular calcium levels in cataract.

Regulation of sarco/endoplasmic and plasma membrane calcium ATPase gene expression by calcium in cultured human lens epithelial cells.

Since Ca(2+)-ATPase is a major determinant of calcium homeostasis in the lens, we examined the expression of Ca(2+)-ATPase by calcium. An immortalized human lens epithelial cell line, HLE B-3, was treated with thapsigargin to inhibit sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) releasing calcium from intracellular stores. Isoforms of the plasma membrane Ca(2+)-ATPase (PMCA) and SERCA were quantified by Western blot and quantitative real time reverse transcription polymerase chain reaction. We showed that both PMCA1 and SERCA3 isoform protein and mRNA are upregulated two- to three-fold in thapsigargin-treated HLE B-3 cells in a time and dose-dependent manner. Thapsigargin did not change the protein or mRNA levels of PMCA2, 3, 4 or SERCA2b. Considering the harmful effects of increased intracellular calcium levels, the upregulation of both SERCA and PMCA pumps suggests it is a compensatory mechanism to restore the calcium concentration to the physiological resting level.

Ticagrelor and Eptifibatide Bolus Versus Ticagrelor and Eptifibatide Bolus With 2-Hour Infusion in High-Risk Acute Coronary Syndromes Patients Undergoing Early Percutaneous Coronary Intervention.

BACKGROUND: In patients with non-ST-segment elevation acute coronary syndromes, inhibition of platelet aggregation (IPA) with a potent P2Y12 inhibitor, ticagrelor, was inferior to tirofiban infusion at 2 hours, indicating that glycoprotein IIb/IIIa inhibitors are still needed. Ticagrelor and eptifibatide bolus only may maximally inhibit platelet aggregation and decrease bleeding, but IPA with ticagrelor and eptifibatide bolus versus 2-hour infusion is unknown. METHODS AND RESULTS: A total of 70 P2Y12-naïve patients, with high-risk non-ST-segment elevation acute coronary syndromes, were randomized to ticagrelor and eptifibatide bolus (group 1) versus ticagrelor and eptifibatide bolus with 2-hour infusion (group 2). Levels of IPA with ADP, thrombin receptor-activating peptide, collagen, and high on-treatment platelet reactivity were measured by light transmission aggregometry at baseline and at 2, 6, and 24 hours after percutaneous coronary intervention in both groups. The primary end point, IPA with ADP 20 µmol/L at 2 hours, was 99.59±0.43% in group 1 versus 99.88±1.0% in group 2 (P<0.001 for noninferiority). High on-treatment platelet reactivity with ADP was zero at 2, 6, and 24 hours in both groups. IPA levels with ADP, thrombin receptor-activating peptide, and collagen were significantly higher at 2 and 6 hours than at 24 hours in both groups. Periprocedural myocardial infarction was not significantly different between the groups. Hemoglobin level was significantly less at 24 hours versus baseline in group 2 (13.35±1.8 versus 12.38±1.8 g/dL, respectively; P<0.01). CONCLUSIONS: Ticagrelor and eptifibatide bolus maximally inhibited platelet aggregation at 2 hours, which was associated with no significant hemoglobin drop after percutaneous coronary intervention. This obviates the need for eptifibatide 2-hour infusion and might decrease bleeding complications. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01919723.