gms | German Medical Science

62nd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Polish Society of Neurosurgeons (PNCH)

German Society of Neurosurgery (DGNC)

7 - 11 May 2011, Hamburg

Influence of oxygen concentration and irradiation fractionation on Aminolevulinic Acid (ALA) guided Photodynamic Therapy (PDT) on human malignant glioma cells in vitro

Meeting Abstract

Search Medline for

  • R. Pannewitz - Klinik für Neurochirurgie, Universitätsklinikum Düsseldorf
  • W. Stummer - Klinik für Neurochirurgie, Universitätsklinikum Münster

Deutsche Gesellschaft für Neurochirurgie. Polnische Gesellschaft für Neurochirurgen. 62. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgen (PNCH). Hamburg, 07.-11.05.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. DocP 085

DOI: 10.3205/11dgnc306, URN: urn:nbn:de:0183-11dgnc3066

Published: April 28, 2011

© 2011 Pannewitz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Outline

Text

Objective: Resection followed by radiation and chemotherapy are well established treatments for high-grade gliomas. However, in almost 100% of cases, the tumor recurs. Therefore innovative treatment options are required. The extent of resection, optimally guided by ALA, is important for overall outcome. Beyond that, ALA is a well examined compound for photodynamic treatment after or instead of surgery in several disciplines. In this study we examined the influence of excess oxygen supply and light fractionation on the efficacy of PDT. Light fractionation theoretically results in sensitizer replenishment during irradiation gaps in comparison to continued irradiaiton.

Methods: G112 cells were disseminated on 96-well-plates and incubated in ALA and placed in a self-developed irradiation chamber. First of all, the cells were treated by ALA (25 μg/ml cell suspension) and light (25mW/cm2) without additional oxygen and with only one single fraction of irradiation (450s). This resulted in 50% cell death as shown by colorimetric ELISA-Reader. Oxygen-treated cells were maintained in an oxygen enriched atmosphere (100%) for 15 minutes. For safety reasons oxygen supply was turned off during laser treatment. For fractionation, cells underwent irradiation treatment with 3 separate treatments with duration of 150 seconds and delays of 10 minutes.

Results: Oxygen pre-treatment resulted in significantly increased tumor cell death (up to 28%), whereas cell death was decreased in the group treated by light fractionation (up to 34%).

Conclusions: Our results demonstrate excess oxygen to improve the efficacy of photodynamic therapy while fractionation cannot improve the effect. Clinical PDT should therefore be performed with a high intraoperative fraction of inspired oxygen (FiO2).