TY - JOUR

T1 - Different Effects of Ranibizumab and Bevacizumab on Platelet Activation Profile

AU - Sobolewska, Bianka

AU - Grimmel, Cornelia

AU - Gatsiou, Aikaterini

AU - Sopova, Kateryna

AU - Klein, Judith

AU - Biedermann, Tilo

AU - Stellos, Konstantinos

AU - Ziemssen, Focke

PY - 2015/10/31

Y1 - 2015/10/31

N2 - PURPOSE: The aim of the study was to evaluate the potential influence of ranibizumab and bevacizumab on platelet activation and aggregation, which are critical processes in the pathogenesis of arterial thromboembolic events (ATEs).METHODS: For the assessment of platelet function, flow cytometry and aggregometry were employed. Platelets were isolated from healthy volunteers and exposed to ranibizumab (1 mg/ml and 150 ng/ml) and bevacizumab (2.5 mg/ml and 3 μg/ml) or their solvents for 10 and 30 min prior to the addition of TRAP (25 μM), PAR-4-AP (25 μM) or thrombin (0.02 U/ml). The surface expression of activated GP IIb/IIIa, P-selectin (CD62P) and platelet-bound stromal cell-derived factor-1 (SDF-1) was measured on resting (nonactivated) and activated platelets by flow cytometry. The platelet aggregation capacity was examined using light transmission aggregometry.RESULTS: The expression of surface activation markers did not differ significantly between nonstimulated and TRAP-, PAR-4-AP- or thrombin-activated platelets after incubating with ranibizumab. However, GP IIb/IIIa, CD62P and SDF-1 were significantly downregulated in PAR-4-AP- and thrombin-activated platelets after exposure to bevacizumab 2.5 mg/ml. In addition, ranibizumab- and bevacizumab-FITC were significantly increased in all activated platelets. No significant differences were observed in the aggregation of activated platelets after incubation with ranibizumab or bevacizumab.CONCLUSION: All ranibizumab concentrations as well as the bevacizumab concentration of 3 μg/ml had no influence on platelet activation and aggregation. Therefore, this in vitro study did not show any relationship between the exposition of activated platelets to ranibizumab or bevacizumab and the development of ATEs. However, the highest level of bevacizumab interfered with platelet activation, leading to downregulation of platelet activation markers. This observation might explain why the systemic treatment with high-dose bevacizumab could be associated with an increased risk of bleeding. Regarding the use of lower intravitreal dosages, further research should focus on the complex interactions between platelets and other cells, such as endothelial cells, which might stronger relate to a potentially increased risk of ATEs and depend on systemic vascular endothelial growth factor levels. Facing the different activation profiles, the diverse effects of the drugs on the cellular level have to be critically scrutinized for their clinical relevance.

AB - PURPOSE: The aim of the study was to evaluate the potential influence of ranibizumab and bevacizumab on platelet activation and aggregation, which are critical processes in the pathogenesis of arterial thromboembolic events (ATEs).METHODS: For the assessment of platelet function, flow cytometry and aggregometry were employed. Platelets were isolated from healthy volunteers and exposed to ranibizumab (1 mg/ml and 150 ng/ml) and bevacizumab (2.5 mg/ml and 3 μg/ml) or their solvents for 10 and 30 min prior to the addition of TRAP (25 μM), PAR-4-AP (25 μM) or thrombin (0.02 U/ml). The surface expression of activated GP IIb/IIIa, P-selectin (CD62P) and platelet-bound stromal cell-derived factor-1 (SDF-1) was measured on resting (nonactivated) and activated platelets by flow cytometry. The platelet aggregation capacity was examined using light transmission aggregometry.RESULTS: The expression of surface activation markers did not differ significantly between nonstimulated and TRAP-, PAR-4-AP- or thrombin-activated platelets after incubating with ranibizumab. However, GP IIb/IIIa, CD62P and SDF-1 were significantly downregulated in PAR-4-AP- and thrombin-activated platelets after exposure to bevacizumab 2.5 mg/ml. In addition, ranibizumab- and bevacizumab-FITC were significantly increased in all activated platelets. No significant differences were observed in the aggregation of activated platelets after incubation with ranibizumab or bevacizumab.CONCLUSION: All ranibizumab concentrations as well as the bevacizumab concentration of 3 μg/ml had no influence on platelet activation and aggregation. Therefore, this in vitro study did not show any relationship between the exposition of activated platelets to ranibizumab or bevacizumab and the development of ATEs. However, the highest level of bevacizumab interfered with platelet activation, leading to downregulation of platelet activation markers. This observation might explain why the systemic treatment with high-dose bevacizumab could be associated with an increased risk of bleeding. Regarding the use of lower intravitreal dosages, further research should focus on the complex interactions between platelets and other cells, such as endothelial cells, which might stronger relate to a potentially increased risk of ATEs and depend on systemic vascular endothelial growth factor levels. Facing the different activation profiles, the diverse effects of the drugs on the cellular level have to be critically scrutinized for their clinical relevance.

KW - Angiogenesis Inhibitors/pharmacology

KW - Bevacizumab/pharmacology

KW - Blood Platelets/drug effects

KW - Chemokine CXCL12/metabolism

KW - Flow Cytometry

KW - Humans

KW - P-Selectin/metabolism

KW - Peptide Fragments/pharmacology

KW - Platelet Activation/physiology

KW - Platelet Aggregation/physiology

KW - Platelet Glycoprotein GPIIb-IIIa Complex/metabolism

KW - Ranibizumab/pharmacology

KW - Receptors, Thrombin/administration & dosage

KW - Thrombin/pharmacology

KW - Vascular Endothelial Growth Factor A/antagonists & inhibitors

U2 - 10.1159/000437057

DO - 10.1159/000437057

M3 - Journal article

C2 - 26305017

VL - 234

SP - 195

EP - 210

JO - Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde

JF - Ophthalmologica. Journal international d'ophtalmologie. International journal of ophthalmology. Zeitschrift fur Augenheilkunde

SN - 0030-3755

IS - 4

ER -