Induction of cAMP-dependent protein kinase A activity in human skin fibroblasts and rat osteoblasts by extremely low-frequency electromagnetic fields.

Radiation and environmental biophysics · 1999 · Mixed · Low evidence

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MixedLow evidencePaper 5366

Exposure to sinusoidal ELF-EMF (7–8 mT, 20 Hz) for 60 min increased PKA activity in human skin fibroblasts (~2-fold) and rat embryonic osteoblasts (~1.7-fold). With long-term exposure up to 7 days (1 h-on/1 h-off), PKA activity showed transient stimulation du…

Study snapshot

PublicationRadiation and environmental biophysics · 1999

Study typein_vitro

Reported directionMixed

Evidence ratingLow

Abstract

Sinusoidal extremely low-frequency electromagnetic fields (ELF-EMF; 7-8 mT, 20 Hz) have already been shown to inhibit proliferation and to accelerate terminal differentiation of human skin fibroblasts in vitro. In order to elucidate the underlying processes of signal transduction, we analysed the activity of cAMP-dependent protein kinase (PKA). EMF exposure for 60 min resulted in an increased PKA activity in human skin fibroblasts (2-fold) and rat embryonic osteoblasts (1.7-fold). Long-term exposure for up to 7 days with a constant 1 h-on/1 h-off EMF exposure rhythm indicated a transient stimulation of PKA activity during the first two exposure rhythms followed by a decrease to the baseline levels of sham-exposed controls. Based on these results, we postulate that a modulation of proliferation and differentiation processes in cells of mesenchymal origin is triggered by an immediate and transient EMF-induced increase in PKA activity.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typein_vitro

Effect directionmixed

PopulationHuman skin fibroblasts and rat embryonic osteoblasts (cell cultures)

Sample sizeNot supplied

ExposureELF · 0.02 MHz · 60 min; up to 7 days (1 h-on/1 h-off rhythm)

Evidence strengthLowConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

cAMP-dependent protein kinase A (PKA) activity

Limitations

In vitro study (cell culture), limiting direct inference to human health outcomes
Sample size and statistical details not provided in the abstract
Exposure source and other dosimetry details beyond field strength/frequency not described in the abstract

View raw extracted JSON

{
  "study_type": "in_vitro",
  "exposure": {
    "band": "ELF",
    "source": null,
    "frequency_mhz": 0.02,
    "sar_wkg": null,
    "duration": "60 min; up to 7 days (1 h-on/1 h-off rhythm)"
  },
  "population": "Human skin fibroblasts and rat embryonic osteoblasts (cell cultures)",
  "sample_size": null,
  "outcomes": [
    "cAMP-dependent protein kinase A (PKA) activity"
  ],
  "main_findings": "Exposure to sinusoidal ELF-EMF (7–8 mT, 20 Hz) for 60 min increased PKA activity in human skin fibroblasts (~2-fold) and rat embryonic osteoblasts (~1.7-fold). With long-term exposure up to 7 days (1 h-on/1 h-off), PKA activity showed transient stimulation during the first two exposure rhythms and then decreased back to baseline levels of sham-exposed controls.",
  "effect_direction": "mixed",
  "limitations": [
    "In vitro study (cell culture), limiting direct inference to human health outcomes",
    "Sample size and statistical details not provided in the abstract",
    "Exposure source and other dosimetry details beyond field strength/frequency not described in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-frequency electromagnetic fields",
    "ELF-EMF",
    "20 Hz",
    "7-8 mT",
    "protein kinase A",
    "PKA",
    "cAMP-dependent",
    "human skin fibroblasts",
    "rat embryonic osteoblasts",
    "signal transduction"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.2,
      "reason": "ELF-EMF exposure parameters are relevant to ELF exposure contexts, though no specific occupational setting is stated."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1007/s004110050155
PubMed: 10525956

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