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Platelet activation markers in patients with peripheral arterial disease--a prospective comparison of different
P Gresele1, M Catalano, C Giammarresi
1Institute of Internal Medicine and Vascular Medicine, University of Perugia, Italy.
Insights
Peripheral vascular disease (PVD) patients show increased platelet activation. Urinary 11-dehydro-TXB2 levels were significantly higher in PVD patients, indicating it
Area of Science:
- Cardiovascular Medicine
- Hematology
- Biochemistry
Background:
- Peripheral vascular disease (PVD) is a marker of systemic atherosclerosis.
- PVD is linked to increased risks of coronary heart and cerebrovascular diseases.
- In vivo platelet activation is implicated in PVD, but comparative data on diagnostic tests are lacking.
Purpose of the Study:
- To compare the sensitivity of various in vivo and in vitro platelet function tests in patients with PVD.
- To identify the most reliable marker for in vivo platelet activation in PVD.
Main Methods:
- Prospective comparison of four in vivo platelet activation tests (plasma betaTG, plasma PF4, intraplatelet betaTG, urinary 11-dehydro-TXB2) and one in vitro test (ADP-induced platelet aggregation).
- Study included 63 patients with intermittent claudication (PVD) and 18 healthy controls.
- Measurements included specific platelet proteins and urinary thromboxane metabolites.
Main Results:
- No significant differences were observed between PVD patients and controls for plasma betaTG, plasma PF4, betaTG/PF4 ratio, intraplatelet betaTG, or ADP-induced platelet aggregation.
- Urinary 11-dehydro-TXB2 excretion was significantly higher in the PVD group compared to controls (p < 0.001).
Conclusions:
- Urinary 11-dehydro-TXB2 is a more sensitive indicator of in vivo platelet activation in PVD patients than plasma markers or in vitro aggregation tests.
- This finding suggests urinary 11-dehydro-TXB2 may be a valuable diagnostic tool for assessing platelet activity in PVD.
- Elevated platelet activation in PVD highlights potential therapeutic targets for cardiovascular risk reduction.
Abstract:
Peripheral vascular disease (PVD) is an indicator of diffuse atherosclerosis and is associated with a greatly increased incidence of coronary heart and cerebrovascular disease. Although several studies have assessed whether in vivo platelet activation takes place in patients with PVD, no data are available comparing different platelet function tests in this patient population. We have compared prospectively four tests for the measurement of in vivo platelet activation (plasma betaTG, plasma PF4, intraplatelet betaTG and urinary excretion of 11-dehydro-TXB2) and one in vitro platelet function test (ADP-induced platelet aggregation) in 63 well-characterized patients with intermittent claudication and in 18 age- and sex-matched healthy volunteers. No statistically significant difference was found between patients and controls for plasma betaTG (20.0 +/- 11.8 vs. 18.8 +/- 9.0 ng/ml, respectively), plasma PF4 (5.2 +/- 2.9 vs. 6.3 +/- 3.5 ng/ml), betaTG/PF4 ratio (4.0 +/- 2.9 vs. 3.6 +/- 1.8), intraplatelet betaTG (4503 +/- 1482 vs. 4059 +/- 1065 ng/ml), and threshold aggregatory concentration of ADP (1.7 +/- 0.72 vs. 1.45 +/- 0.56 microM). Urinary 11-dehydro-TXB2 was instead significantly higher in the PVD group (55.4 +/- 27.5 vs. 26.7 +/- 7.0 ng/h, p <0.001). Our study shows that urinary 11-dehydro-TXB2 is a more sensitive index of in vivo platelet activation than the measurement of either platelet specific proteins or of in vitro platelet aggregation in patients with PVD.