Related Experiment Videos
Platelet kinetics in patients with atherosclerosis
H Sinzinger1, I Virgolini, P Fitscha
1Department of Nuclear Medicine, University of Vienna, Ludwig Boltzmann-Institute for Nuclear Medicine, Austria.
Insights
Platelet survival is significantly reduced in patients with atherosclerosis. While imaging showed no differences, altered thromboxane B2 metabolism suggests increased platelet activation in these individuals.
Area of Science:
- Cardiovascular Medicine
- Hematology
- Nuclear Medicine
Background:
- Atherosclerosis is a complex disease affecting arteries.
- Platelet activation plays a crucial role in thrombotic events associated with atherosclerosis.
Purpose of the Study:
- To investigate platelet kinetics and activation markers in patients with clinically manifest atherosclerosis.
- To assess the utility of radiolabeled autologous platelets in visualizing atherosclerotic disease.
Main Methods:
- Autologous platelets were labeled with Indium-111 oxine in 12 atherosclerosis patients and 6 controls.
- Platelet half-life was determined using gamma camera imaging.
- Serum and plasma thromboxane B2 levels and arachidonic acid conversion were measured.
Main Results:
- Platelet half-life was significantly shorter (p < 0.01) in patients with atherosclerosis.
- No significant differences in platelet distribution were observed via gamma imaging.
- Plasma thromboxane B2 showed a trend towards increase, and conversion of arachidonic acid to thromboxane B2 was elevated in atherosclerotic patients.
Conclusions:
- Atherosclerosis is associated with accelerated platelet turnover.
- Despite normal imaging, altered thromboxane B2 metabolism indicates increased platelet activation in atherosclerosis.
Abstract:
In 12 patients (8 males, 4 females; 59.4 +/- 6.2 years) with clinically manifest atherosclerosis (peripheral vascular disease stage II according to Fontaine and coronary heart disease) without any risk factor and 6 controls (4 males, 2 females; 58.5 +/- 7.06 years) autologous platelets were labelled using 100 microCi 111-In-oxine. In parallel, serum- and plasma-thromboxane (TX) B2 and conversion of exogenous radiolabelled arachidonic acid towards TXB2 were determined. No difference in labelling efficiency and recovery was noted. Platelet half-life was significantly (p less than 0.01) shortened in the atherosclerotics. Gamma-camera images were obtained during the first 64 minutes after reinjection as well as 2, 6, 18, 24 and daily up to 1 week after reinjection of autologous radiolabelled platelets. No difference between the patients suffering from atherosclerosis--having either visible atherosclerotic lesions or not--could be discovered. Serum-TXB2 was comparable, whereas plasma-TXB2 showed a trend towards an increase and the conversion from exogenous 14C-AA to 14C-TXB2 was increased in atherosclerosis.