Weak electromagnetic fields (50 Hz) elicit a stress response in human cells.

Abstract

The aim of this study was to demonstrate the expression of heat shock (HS) genes in human cells in response to extremely low-frequency electromagnetic fields (ELF-EMF) alone and in combination with thermal stress. After exposing human myeloid leukemia (HL-60) cells to the stressor(s) for 30 min we quantified the expression of the HS genes HSP27, HSP60, HSP70 (A, B, and C), HSC70, HSP75, HSP78, and HSP90 (alpha and beta) by RT-PCR. The results clearly show that HS genes, in particular the three HSP70 genes (A, B, and C), are induced by ELF-EMF, a reaction that is enhanced by simultaneous HS (43 degrees C for 30 min). The results show similarities and some significant differences to previous experiments in which transgenic nematodes were used to monitor the induction of the HSP70 gene under similar stress conditions. We also studied the effect of different flux densities on gene expression in the range of 10-140 microT. Even the lowest dose tested (10 microT) resulted in a significant induction of the genes HSP70A, HSP70B, and HSP70C. The reaction to ELF-EMF shows a maximum at a flux density of 60-80 microT. The unusual dose-response relation reveals an interesting difference to other stressors that elicit the HS response.

AI evidence extraction

Main findings

After 30 min exposure, ELF-EMF induced heat shock gene expression in HL-60 cells, particularly HSP70A, HSP70B, and HSP70C; induction was enhanced when combined with simultaneous heat shock (43°C for 30 min). Across 10–140 µT, even 10 µT significantly induced HSP70A/B/C, with a maximum response at 60–80 µT and an unusual dose-response relationship.

Outcomes measured

• Expression/induction of heat shock (HS) genes (HSP27, HSP60, HSP70A/B/C, HSC70, HSP75, HSP78, HSP90α/β) measured by RT-PCR
• Dose-response of HS gene expression across magnetic flux densities (10–140 µT)
• Interaction with thermal stress (43°C for 30 min) on HS gene expression

Limitations

• In vitro study in a leukemia cell line (HL-60), which may not generalize to in vivo human responses
• Sample size and replication details not provided in the abstract
• Exposure source/setup details beyond frequency (50 Hz) and flux density range are not described in the abstract
• Outcomes are gene expression changes; no clinical or organism-level health outcomes reported

Suggested hubs

• occupational-exposure (0.35)
  Study examines 50 Hz ELF magnetic field exposure levels (µT range) relevant to some occupational/environmental settings, though no specific workplace source is stated.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "30 min"
    },
    "population": "Human myeloid leukemia (HL-60) cells",
    "sample_size": null,
    "outcomes": [
        "Expression/induction of heat shock (HS) genes (HSP27, HSP60, HSP70A/B/C, HSC70, HSP75, HSP78, HSP90α/β) measured by RT-PCR",
        "Dose-response of HS gene expression across magnetic flux densities (10–140 µT)",
        "Interaction with thermal stress (43°C for 30 min) on HS gene expression"
    ],
    "main_findings": "After 30 min exposure, ELF-EMF induced heat shock gene expression in HL-60 cells, particularly HSP70A, HSP70B, and HSP70C; induction was enhanced when combined with simultaneous heat shock (43°C for 30 min). Across 10–140 µT, even 10 µT significantly induced HSP70A/B/C, with a maximum response at 60–80 µT and an unusual dose-response relationship.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro study in a leukemia cell line (HL-60), which may not generalize to in vivo human responses",
        "Sample size and replication details not provided in the abstract",
        "Exposure source/setup details beyond frequency (50 Hz) and flux density range are not described in the abstract",
        "Outcomes are gene expression changes; no clinical or organism-level health outcomes reported"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "ELF-EMF",
        "50 Hz",
        "magnetic flux density",
        "10–140 µT",
        "HL-60",
        "human cells",
        "heat shock response",
        "HSP70",
        "RT-PCR",
        "thermal stress",
        "dose-response"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.34999999999999997779553950749686919152736663818359375,
            "reason": "Study examines 50 Hz ELF magnetic field exposure levels (µT range) relevant to some occupational/environmental settings, though no specific workplace source is stated."
        }
    ]
}

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