gms | German Medical Science

60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

Platelet depletion does not influence growth and angiogenesis of GBM in vivo despite proliferative and migratory effects of platelet cytokines in vitro

Meeting Abstract

  • M. Brockmann - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • B. Bender - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • E. Plaxina - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • I. Nölte - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • R. Erber - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • S. Schambach - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • C. Groden - Abteilung für Neuroradiologie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim
  • L. Schilling - Abteilung für Neurochirurgie, Medizinische Fakultät Mannheim der Universität Heidelberg, Mannheim

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocP14-10

DOI: 10.3205/09dgnc408, URN: urn:nbn:de:0183-09dgnc4086

Published: May 20, 2009

© 2009 Brockmann et al.
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Outline

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Objective: Thrombocytosis is an independent predictor of short survival in patients with glioblastoma (GBM) and in various other tumor entities. Prothrombotic activity of the tumor microcirculation has been suggested to induce platelet activation resulting in a release of angiogenic cytokines from activated platelets. Controversial results regarding the influence of platelets on tumor growth and angiogenesis exist. We analyzed the effects of platelet-released cytokines on GBM and endothelial cell proliferation and migration in vitro, the effect of reducing platelet counts on glioblastoma growth and angiogenesis in an in vivo model, and the correlation between platelet count and vessel density in patients with GBM.

Methods: Cultured GBM cells (U87, U373) and HUVECs were coincubated with platelet-released cytokines, and stimulation of proliferation and migration as well as sprouting and formation of capillary-like structures were analyzed. In vivo, glioblastoma cells (G55T2) were implanted subcutaneously in mice followed by platelet depletion starting 1 or 8 days after implantation of the tumor cells. Tumor volume was analyzed on day 14. Microvessel density (MVD) and proliferative activity were determined in tumor samples. Finally, MVD and proliferative activity in tumor samples from 57 patients were correlated with the patients’ preoperative platelet counts.

Results: In vitro, cytokines released from activated platelets stimulated proliferation and migration of glioblastoma cells and HUVECs significantly in a dose dependent manner. Despite these in vitro-effects, tumor volume, proliferative index, and vessel density analyzed 14 days after implantation did not differ between animals with a normal platelet count and platelet-depleted animals. Proliferative activity and vessel density determined in tumor samples from patients operated because of GBM did not show any correlation with the patients’ preoperative platelet count.

Conclusions: We conclude that despite the distinct proliferation- and chemotaxis-stimulating effects of platelet-derived cytokines in vitro, platelets do not exert a major influence on tumor growth and angiogenesis in vivo.