Topic

in vitro experiments on exposure to the high frequency fields of mobile telecommunications.
C. blood-brain barrier

Start

01.12.2003

End

31.11.2006

Project Management

University of Münster

Objective

The objective of this research project was to investigate whether the differential gene expression in cells of the blood-brain barrier is affected by the high frequency fields of mobile communication technology (RF fields). Primary capillary endothelium cells from rats were used as a model for the blood-brain barrier. The effects of RF-fields relevant for mobile communication (GSM and UMTS) on the gene expression pattern of cell culture models were examined with the help of a method used to screen gene expression (chip arrays). Through the screening carried out in this study, target proteins of the blood-brain barrier, which are influenced by RF-fields of mobile communication technology, were identified.

Results

The present study aimed at investigating the impact of mobile phone electromagnetic fields on the blood brain-barrier in vitro. The analysis of differential gene expression was chosen as hypothesis-free screening tool in order to identify genes that were up- or down regulated due to RF-EMF exposure. Primary cultures of rat brain microvascular endothelial cells were permanently exposed for 72 hours to either UMTS or GSM1800 signals at SAR-values ranging from 0.4 to 8.0 W/kg in a radial waveguide. A sham exposure was performed for each experiment in parallel. RNA was isolated from the cell cultures and underwent genechip array and quantitative real time PCR analysis. A comparison of expression profiles of exposed and sham exposed revealed 14 (UMTS) or respectively 5 (GSM1800) genes that were significantly regulated at least at one SAR, most of them at 3 W/kg. These genes include candidates encoding for proteins known for their relevance for proper BBB function such as members of the SLC-Transporter family, vasoactive receptors, cellular differentiation, signal transduction and the tight junction protein claudin-1. Up- or down regulations in gene expression were relatively weak for all samples and typically ranged between 1.5 to 3-fold changes when compared to sham exposed controls. The comparison of data for all four SAR-values tested here did not identify any dose-response relationship. Overall this study identified several candidate genes that showed differential expression due to non-thermal (less than +1°C warming) EMF influence, including Claudin-1, a tight junction protein, but no exposure-response relationship could be identified.

The first interim report gives a short review over the methods of cell culture used in the study, the preparation of the in vitro model for the blood brain barrier and the status of the setup for the exposure of the cell culture system. The report is available as PDF-file in German (63 kB).

In the second interim report the researchers give a short description about the establishment and characterisation of the cell culture model used for the investigation of the blood brain barrier. The interim report is available as PDF-file in German (96 kB).

The final report, including a review of the relevant scientific literature concerning the topic of possible influences of RF-fields on the blood-brain barrier is available as PDF-file in German (2,13 MB).

Conclusion

Several candidate genes were changed in their expression, but no plausible pattern was detected. Since there are neither indications from in vitro studies (Franke et al. 2005) nor from recent in vivo studies about adverse effects on the permeability of the blood brain barrier, the study design and the data obtained do not allow to draw conclusions concerning health relevant effects in human. Nevertheless, independent verification of the results and further investigation of the candidate genes is recommended.