Gene Expression Analysis in Human Peripheral Blood Cells after 900 MHz RF-EMF Short-Term Exposure.

Abstract

Radiofrequency electromagnetic fields (RF-EMF) are a basic requirement of modern wireless communication technology. Statutory thresholds of RF-EMF are established to limit relevant additional heat supply in human tissue. Nevertheless, to date, questions concerning nonthermal biological effects have yet to be fully addressed. New versions of microarrays (8 × 60K v2) provide a higher resolution of whole genome gene expression to display adaptive processes in cells after irradiation. In this ex vivo/ in vitro study, we irradiated peripheral blood cells from five donors with a continuous wave of 900 MHz RF-EMF for 0, 30, 60 and 90 min. Gene expression changes ( P ≤ 0.05 and ≥twofold differences above or below the room temperature control exposed samples) were evaluated with microarray analysis. The results were compared with data from room temperature + 2°C samples. Verification of microarray results was performed using bioinformatic analyses and qRT-PCR. We registered a lack of an EMF-specific gene expression response after applying the false discovery rate adjustment (FDR), using a high-stringency approach. Low-stringency analysis revealed 483 statistically significant deregulated transcripts in all RF-EMF groups relative to the room temperature exposed samples without an association with their corresponding room temperature + 2°C controls. Nevertheless, these transcripts must be regarded as statistical artefacts due to the absence of a targeted biological response, including enrichment and network analyses administered to microarray expressed gene subset profiles. Correspondingly, 14 most promising candidate transcripts examined by qRT-PCR displayed an absence of correlation with respect to the microarray results. In conclusion, these findings indicate that 900 MHz EMF exposure establishing an average specific absorption rate of 9.3 W/kg to whole blood cells is insufficient to induce nonthermal effects in gene expression during short-time exposure up to 90 min.

AI evidence extraction

Main findings

Using a high-stringency approach with false discovery rate adjustment, the authors report no EMF-specific gene expression response after 900 MHz RF-EMF exposure (up to 90 min; average SAR 9.3 W/kg). Low-stringency analysis yielded 483 deregulated transcripts, but these were interpreted as statistical artefacts and were not supported by enrichment/network analyses or qRT-PCR of 14 candidate transcripts.

Outcomes measured

• Whole-genome gene expression (microarray)
• qRT-PCR verification of candidate transcripts

Limitations

• Ex vivo/in vitro design using isolated peripheral blood cells (not an in vivo human exposure study)
• Small number of donors (n=5)
• Short-term exposure only (up to 90 minutes)
• Findings depend on statistical stringency; low-stringency signals were not validated by qRT-PCR

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "RF",
        "source": null,
        "frequency_mhz": 900,
        "sar_wkg": 9.300000000000000710542735760100185871124267578125,
        "duration": "0, 30, 60, and 90 min (continuous wave)"
    },
    "population": "Human peripheral blood cells (five donors; ex vivo/in vitro)",
    "sample_size": 5,
    "outcomes": [
        "Whole-genome gene expression (microarray)",
        "qRT-PCR verification of candidate transcripts"
    ],
    "main_findings": "Using a high-stringency approach with false discovery rate adjustment, the authors report no EMF-specific gene expression response after 900 MHz RF-EMF exposure (up to 90 min; average SAR 9.3 W/kg). Low-stringency analysis yielded 483 deregulated transcripts, but these were interpreted as statistical artefacts and were not supported by enrichment/network analyses or qRT-PCR of 14 candidate transcripts.",
    "effect_direction": "no_effect",
    "limitations": [
        "Ex vivo/in vitro design using isolated peripheral blood cells (not an in vivo human exposure study)",
        "Small number of donors (n=5)",
        "Short-term exposure only (up to 90 minutes)",
        "Findings depend on statistical stringency; low-stringency signals were not validated by qRT-PCR"
    ],
    "evidence_strength": "low",
    "confidence": 0.85999999999999998667732370449812151491641998291015625,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "RF-EMF",
        "900 MHz",
        "continuous wave",
        "specific absorption rate",
        "SAR 9.3 W/kg",
        "peripheral blood cells",
        "microarray",
        "gene expression",
        "qRT-PCR",
        "false discovery rate"
    ],
    "suggested_hubs": []
}

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