Abstract
Background and Objectives. Inhibition of soluble fibrinogen binding to activated platelets represents the target of pharmacologic approach with antagonists of the glycoprotein IIb/IIIa (GPIIb/IIIa) complex. In this study we assessed the effects of abciximab, a recombinant chimeric Fab fraction of the antibody against GPIIb/IIIa, on several markers of platelet activation. Design and Methods. The platelet surface expression of GPIIb/IIIa was measured by a flow cytometry technique using a two-color assay. GPIIb/IIIa was detected by FITC-conjugated antibodies in whole blood, either unstimulated or exposed to platelet stimuli. The following antibodies were used: CD41, which recognizes the IIb/IIIa complex both in activated and non-activated conformers, and PAC-1, which is directed toward the activated conformer of GPIIb/IIIa. In addition, the same blood sample was incubated with CD62 antibody to measure P-selectin, as a marker of α-granule degranulation. The effect of abciximab was also assessed by experiments carried out on shear stress-induced platelet aggregation, a test that appears to be a predictor of platelet hemostatic function. Results. Abciximab inhibited CD41 binding to glycoprotein IIb (GPIIb) in a concentration-dependent manner and also inhibited the binding of PAC-1 to active GPIIb/IIIa. In contrast, membrane-associated P-selectin was significantly increased by the drug, which suggests that blockade of GPIIb/IIIa receptors results in an increased platelet degranulation in response to agonists. Shear stress-induced platelet aggregation was inhibited by abciximab, with a more pronounced effect on blood filtration, which represents an index of platelet aggregate formation. Interpretation and Conclusions. Our results indicate that GPIIb/IIIa blockade by abciximab is accompanied by an increase of α-granule secretion, suggesting that different mechanisms regulate these aspects of platelet activation. The described flow cytometry technique, that allows the simultaneous in vitro detection of several platelet markers, is a suitable method for assessing the effects of agents which interfere with platelet function.
| Original language | English |
|---|---|
| Pages (from-to) | 192-198 |
| Number of pages | 7 |
| Journal | Haematologica |
| Volume | 86 |
| Issue number | 2 |
| Publication status | Published - 2001 |
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Keywords
- Abciximab
- Flow cytometry
- Glycoprotein IIb/IIIa
- P-selectin
- Platelets
ASJC Scopus subject areas
- Hematology
Cite this
In vitro measurement of platelet glycoprotein IIb/IIIa receptor blockade by abciximab : Interindividual variation and increased platelet secretion. / Rossi, F.; Rossi, E.; Pareti, F. I.; Colli, S.; Tremoli, E.; Gallo, L.
In: Haematologica, Vol. 86, No. 2, 2001, p. 192-198.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - In vitro measurement of platelet glycoprotein IIb/IIIa receptor blockade by abciximab
T2 - Interindividual variation and increased platelet secretion
AU - Rossi, F.
AU - Rossi, E.
AU - Pareti, F. I.
AU - Colli, S.
AU - Tremoli, E.
AU - Gallo, L.
PY - 2001
Y1 - 2001
N2 - Background and Objectives. Inhibition of soluble fibrinogen binding to activated platelets represents the target of pharmacologic approach with antagonists of the glycoprotein IIb/IIIa (GPIIb/IIIa) complex. In this study we assessed the effects of abciximab, a recombinant chimeric Fab fraction of the antibody against GPIIb/IIIa, on several markers of platelet activation. Design and Methods. The platelet surface expression of GPIIb/IIIa was measured by a flow cytometry technique using a two-color assay. GPIIb/IIIa was detected by FITC-conjugated antibodies in whole blood, either unstimulated or exposed to platelet stimuli. The following antibodies were used: CD41, which recognizes the IIb/IIIa complex both in activated and non-activated conformers, and PAC-1, which is directed toward the activated conformer of GPIIb/IIIa. In addition, the same blood sample was incubated with CD62 antibody to measure P-selectin, as a marker of α-granule degranulation. The effect of abciximab was also assessed by experiments carried out on shear stress-induced platelet aggregation, a test that appears to be a predictor of platelet hemostatic function. Results. Abciximab inhibited CD41 binding to glycoprotein IIb (GPIIb) in a concentration-dependent manner and also inhibited the binding of PAC-1 to active GPIIb/IIIa. In contrast, membrane-associated P-selectin was significantly increased by the drug, which suggests that blockade of GPIIb/IIIa receptors results in an increased platelet degranulation in response to agonists. Shear stress-induced platelet aggregation was inhibited by abciximab, with a more pronounced effect on blood filtration, which represents an index of platelet aggregate formation. Interpretation and Conclusions. Our results indicate that GPIIb/IIIa blockade by abciximab is accompanied by an increase of α-granule secretion, suggesting that different mechanisms regulate these aspects of platelet activation. The described flow cytometry technique, that allows the simultaneous in vitro detection of several platelet markers, is a suitable method for assessing the effects of agents which interfere with platelet function.
AB - Background and Objectives. Inhibition of soluble fibrinogen binding to activated platelets represents the target of pharmacologic approach with antagonists of the glycoprotein IIb/IIIa (GPIIb/IIIa) complex. In this study we assessed the effects of abciximab, a recombinant chimeric Fab fraction of the antibody against GPIIb/IIIa, on several markers of platelet activation. Design and Methods. The platelet surface expression of GPIIb/IIIa was measured by a flow cytometry technique using a two-color assay. GPIIb/IIIa was detected by FITC-conjugated antibodies in whole blood, either unstimulated or exposed to platelet stimuli. The following antibodies were used: CD41, which recognizes the IIb/IIIa complex both in activated and non-activated conformers, and PAC-1, which is directed toward the activated conformer of GPIIb/IIIa. In addition, the same blood sample was incubated with CD62 antibody to measure P-selectin, as a marker of α-granule degranulation. The effect of abciximab was also assessed by experiments carried out on shear stress-induced platelet aggregation, a test that appears to be a predictor of platelet hemostatic function. Results. Abciximab inhibited CD41 binding to glycoprotein IIb (GPIIb) in a concentration-dependent manner and also inhibited the binding of PAC-1 to active GPIIb/IIIa. In contrast, membrane-associated P-selectin was significantly increased by the drug, which suggests that blockade of GPIIb/IIIa receptors results in an increased platelet degranulation in response to agonists. Shear stress-induced platelet aggregation was inhibited by abciximab, with a more pronounced effect on blood filtration, which represents an index of platelet aggregate formation. Interpretation and Conclusions. Our results indicate that GPIIb/IIIa blockade by abciximab is accompanied by an increase of α-granule secretion, suggesting that different mechanisms regulate these aspects of platelet activation. The described flow cytometry technique, that allows the simultaneous in vitro detection of several platelet markers, is a suitable method for assessing the effects of agents which interfere with platelet function.
KW - Abciximab
KW - Flow cytometry
KW - Glycoprotein IIb/IIIa
KW - P-selectin
KW - Platelets
UR - http://www.scopus.com/inward/record.url?scp=0035107399&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035107399&partnerID=8YFLogxK
M3 - Article
C2 - 11224490
AN - SCOPUS:0035107399
VL - 86
SP - 192
EP - 198
JO - Haematologica
JF - Haematologica
SN - 0390-6078
IS - 2
ER -