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Electromagnetic Fields in Biological Systems
Vianale et al. (2008) investigated the effect of an ELF-EMF (50 Hz, 1 mT) on keratinocyte proliferation and production of chemokines, regulated on activation, normal T cell
expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1 α, and IL-8 in the human keratinocyte cell line
HaCaT. Significantly increased growth rates were observed after 48 hours of EMF exposure compared with control cells, whereas no difference in cell viabilities was detected.
Gene expression and release of RANTES, MCP-1, MIP-1 α, and IL-8 were significantly
reduced after 72 hours of exposure. The NF-κB levels became almost undetectable after
only 1 hour of exposure, and they were inversely correlated with cell density. The authors
suggested that ELF-EMF modulates chemokine production and keratinocyte growth
through inhibition of the NF-κB signaling pathway and thus may inhibit inflammatory processes. They postulated that ELF-EMF could represent an additional therapeutic
approach in the treatment of skin injury. The same research group further revealed that
the exposure of HaCaT cells to ELF-EMF increased inducible NOS (iNOS) and eNOS
expression levels (Patruno et al. 2010). These ELF-EMF-dependent increased expression levels were paralleled by increased NOS activities and increased NO production.
In addition, higher levels of activator protein 1 (AP-1) expression as well as a higher cell
proliferation rate were associated with ELF-EMF exposure. In contrast, ELF-EMF exposure decreased COX-2 expression, PGE 2 production, catalase activity, and O 2
− production. The authors postulated that the ability of ELF-EMFs to upregulate NOS activities,
and thus nitrogen intermediates as well as cell proliferation, and to downregulate COX-2
expression and the downstream intermediate PGE 2 , highlights the potential therapeutic
role of ELF-EMFs in wound healing processes.
Ke et al. (2008) investigated the effect of an ELF-EMF (50 Hz, 0.4 mT) on clustering of epidermal growth factor (EGF) receptors and ras protein activation in Chinese
hamster lung (CHL) cells. The results showed that, compared with sham-exposed
cells, 5 minutes of exposure slightly induced EGF receptor clustering and 15 minutes
of exposure significantly enhanced receptor clustering. Ras protein was also activated
after exposure. Exposure to a “noise” EMF (30–90 Hz), at the same intensity and durations, did not significantly affect EGF receptor clustering and ras protein activation.
However, by superimposing the noise EMF, the EGF receptor clustering and ras activation induced by 50 Hz EMF were found to be inhibited. These results suggest that
membrane receptors are one of the most important targets where a 50 Hz EMF interacts with cells and that ras protein participates in the signal transduction process of the
50 Hz EMF. Furthermore, a noise EMF can inhibit the effects caused by a 50 Hz EMF.
The same research group also suggested that membrane receptors are one of the main
targets where an ELF-EMF interacts with cells and that the intensity threshold in the
case of EGF receptors is between 0.05 and 0.1 mT (Sun et al. 2008). An incoherent EMF
could completely inhibit the effects induced by an ELF-EMF of equal or lower intensity.
Salerno et al. (2009) investigated the influence of an ELF-EMF (50 Hz, 0.5 mT) or an
SMF (0.5 mT) on subsets of human CD4 + T cells. The CD4 + T cells can be divided into different subsets on the basis of surface marker expression, such as CD45, and T cells can be
divided into naive (CD45RA + ) and memory (CD45RA − ) cells. The authors found that the
CD4 + CD45RA − T subset was more sensitive after 2 hours of exposure to either of the two
magnetic fields. Decreases in the release/content of interferon (IFN)-γ, in cell proliferation