Neuronal cellular responses to extremely low frequency electromagnetic field exposure: implications regarding oxidative stress and neurodegeneration.

Abstract

Neurodegenerative diseases comprise both hereditary and sporadic conditions characterized by an identifying progressive nervous system dysfunction and distinctive neuopathophysiology. The majority are of non-familial etiology and hence environmental factors and lifestyle play key roles in their pathogenesis. The extensive use of and ever increasing worldwide demand for electricity has stimulated societal and scientific interest on the environmental exposure to low frequency electromagnetic fields (EMFs) on human health. Epidemiological studies suggest a positive association between 50/60-Hz power transmission fields and leukemia or lymphoma development. Consequent to the association between EMFs and induction of oxidative stress, concerns relating to development of neurodegenerative diseases, such as Alzheimer disease (AD), have been voiced as the brain consumes the greatest fraction of oxygen and is particularly vulnerable to oxidative stress. Exposure to extremely low frequency (ELF)-EMFs are reported to alter animal behavior and modulate biological variables, including gene expression, regulation of cell survival, promotion of cellular differentiation, and changes in cerebral blood flow in aged AD transgenic mice. Alterations in inflammatory responses have also been reported, but how these actions impact human health remains unknown. We hence evaluated the effects of an electromagnetic wave (magnetic field intensity 1 mT; frequency, 50-Hz) on a well-characterized immortalized neuronal cell model, human SH-SY5Y cells. ELF-EMF exposure elevated the expession of NOS and O2(-), which were countered by compensatory changes in antioxidant catylase (CAT) activity and enzymatic kinetic parameters related to CYP-450 and CAT activity. Actions of ELF-EMFs on cytokine gene expression were additionally evaluated and found rapidly modified. Confronted with co-exposure to H2O2-induced oxidative stress, ELF-EMF proved not as well counteracted and resulted in a decline in CAT activity and a rise in O2(-) levels. Together these studies support the further evaluation of ELF-EMF exposure in cellular and in vivo preclinical models to define mechanisms potentially impacted in humans.

AI evidence extraction

Main findings

In human SH-SY5Y neuronal cells, 50-Hz, 1 mT ELF-EMF exposure increased NOS expression and superoxide (O2(-)) levels, alongside compensatory changes in catalase (CAT) activity and enzymatic kinetic parameters related to CYP-450 and CAT. Cytokine gene expression was rapidly modified. Under co-exposure with H2O2-induced oxidative stress, ELF-EMF was less well counteracted and was associated with decreased CAT activity and increased O2(-) levels.

Outcomes measured

• NOS expression
• O2(-) (superoxide) levels
• Catalase (CAT) activity
• CYP-450-related enzymatic kinetic parameters
• Cytokine gene expression
• Response to co-exposure with H2O2-induced oxidative stress

Limitations

• In vitro neuronal cell model; human health implications not established in the abstract
• Exposure duration not reported in the abstract
• Sample size/replication details not reported in the abstract

Suggested hubs

• occupational-exposure (0.25)
  Discusses 50/60-Hz power transmission fields and ELF exposure context, though experiments are in vitro.

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "ELF",
        "source": "power transmission fields",
        "frequency_mhz": 0.05000000000000000277555756156289135105907917022705078125,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Human SH-SY5Y immortalized neuronal cells",
    "sample_size": null,
    "outcomes": [
        "NOS expression",
        "O2(-) (superoxide) levels",
        "Catalase (CAT) activity",
        "CYP-450-related enzymatic kinetic parameters",
        "Cytokine gene expression",
        "Response to co-exposure with H2O2-induced oxidative stress"
    ],
    "main_findings": "In human SH-SY5Y neuronal cells, 50-Hz, 1 mT ELF-EMF exposure increased NOS expression and superoxide (O2(-)) levels, alongside compensatory changes in catalase (CAT) activity and enzymatic kinetic parameters related to CYP-450 and CAT. Cytokine gene expression was rapidly modified. Under co-exposure with H2O2-induced oxidative stress, ELF-EMF was less well counteracted and was associated with decreased CAT activity and increased O2(-) levels.",
    "effect_direction": "harm",
    "limitations": [
        "In vitro neuronal cell model; human health implications not established in the abstract",
        "Exposure duration not reported in the abstract",
        "Sample size/replication details not reported in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7800000000000000266453525910037569701671600341796875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "extremely low frequency",
        "ELF-EMF",
        "50 Hz",
        "1 mT",
        "SH-SY5Y",
        "neuronal cells",
        "oxidative stress",
        "NOS",
        "superoxide",
        "catalase",
        "CYP-450",
        "cytokine gene expression",
        "neurodegeneration",
        "Alzheimer disease"
    ],
    "suggested_hubs": [
        {
            "slug": "occupational-exposure",
            "weight": 0.25,
            "reason": "Discusses 50/60-Hz power transmission fields and ELF exposure context, though experiments are in vitro."
        }
    ]
}

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