Study type: Medical/biological study (experimental study)

Whole-genome expression analysis in primary human keratinocyte cell cultures exposed to 60 GHz radiation med./bio.

Published in: Bioelectromagnetics 2012; 33 (2): 147-158

Aim of study (acc. to author)

To study the potential responses of skin cells to millimeter wave exposure.

Background/further details

Four independent replicates per condition were used.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60.4 GHz
Modulation type: CW
Exposure duration: continuous for 1, 6, 24 h

Exposure 1

Main characteristics
Frequency 60.4 GHz
Type
Charakteristic
Exposure duration continuous for 1, 6, 24 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 27 cm
Setup 8.5 cm x 12.7 cm culture plate (six wells) with 0.01 mm cell monolayers in each well placed in an incubator and irradiated from the bottom by a pyramidal horn antenna; horn antenna with an aperture of 22.2 mm x 16.7 mm and 17 dB gain
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 425 mW - - - antenna output power
SAR 39 W/kg minimum calculated - within the outer wells
SAR 49.3 W/kg maximum calculated - within the inner wells
SAR 42.4 W/kg spatial average calculated - averaged over all six wells
power density 1.7 mW/cm² - - - in the outer wells
power density 2.1 mW/cm² - - - in the inner wells
power density 2.3 mW/cm² peak value - - -
power density 1.8 mW/cm² spatial average - - averaged over all six wells

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No significant difference in gene expression was observed when gene expression values were subjected to a stringent statistical analysis (via t-test with a statistical correction). However, when a single t-test (less stringent) was applied, 130 transcripts were found to be potentially modulated after exposure. To further quantitatively analyze these preselected transcripts, real-time RT-PCR was performed on 24 genes with the best combination of high "fold change" and low P-value. Five of them were confirmed as differentially expressed after 6 h of exposure: CRIP2 (a zinc-binding protein involved in signaling, haematopoiesis, and cell proliferation), PLXND1 (a transmembrane receptor involved in development), PTX3 (a protein involved in innate immunity and inflammatory response), SERPINF1 (a secreted endopeptidase inhibitor that has anti-angiogenic and anti-proliferation functions), and TRPV2 (a calcium channel involved in sensory perception).
Compared to other microarray analyses studying the effect of pollutants or drug treatments, the number of responsive genes in the present study is extremely modest. Moreover, the gene expression modification is transient (mostly after 6 h of exposure) and with a limited amplitude (generally with a fold change close to 2). One can only wonder about the consequence on human health, of such subtle changes at cellular level. Thus, the authors conclude that millimeter waves (CW, 60.4 GHz, 1.8 mW/cm²) do not have any dramatic impact on primary cultures of human keratinocytes. However, they cannot exclude that millimeter waves could affect gene expression in vivo because skin is a complex tissue composed of different kinds of cells with various sensitivities.

Study character:

Study funded by

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