Thursday, January 15, 2015

Cell Phone & Wi-Fi EMR Effects on Oxidative Stress & Molecular Pathways in the Brain

Joel's comments:
Excerpted below are the sections of this review paper by Nazıroğlu and Akman (2014)  that address blood-brain barrier penetration. Blood-brain barrier penetration after exposure to low intensity (as opposed to greater intensity) microwave radiation has been observed in various studies since it was first reported by Allan Frey in 1975.

Cell Phone & Wi-Fi EMR Effects on Oxidative Stress & Molecular Pathways in the Brain

This phenomenon is problematic for the development of safe RF regulatory standards as well as for the development of harm reduction recommendations via personal behavior change. I would be interested in learning what other people think about this line of research, especially its policy implications.

"Studies have shown that neurological damage can be observed at exposure levels of 0.12 mW/kg (Eberhardt et al. 2008). This is less than one eighth of the average exposure level of 1 mW/kg found 150–200 m from a mobile phone mast. The researchers concluded that 'the weakest fields are the biologically most harmful'.”

Eberhardt JL, Persson BR, Brun AE, Salford LG, Malmgren LO (2008) Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones. Electromagn Biol Med 27(3):215–129
Effects of Cellular Phone- and Wi-Fi-Induced Electromagnetic Radiation on Oxidative Stress and Molecular Pathways in Brain

Mustafa Nazıroğlu, Hatice Akman. Effects of Cellular Phone- and Wi-Fi-Induced Electromagnetic Radiation on Oxidative Stress and Molecular Pathways in Brain.
Systems Biology of Free Radicals and Antioxidants. 2014, pp 2431-244.
It has been suggested that the widespread use of cellular telephones and wireless devices may result in increased health risks resulting from brain exposure to electromagnetic radiation (EMR). The situation has prompted many investigations into the interaction between EMR and neuronal cells, even at intensities not able to produce thermal effects. This chapter reviews the effects of Wi-Fi (2.45 GHz) EMR exposure on the central nervous system in humans and experimental animals.

Several studies have suggested that EMR emitted by wireless devices can interfere with learning and memory in both animal models and human, but the results obtained are controversial and the molecular basis of this interaction is still unclear. Electromagnetic radiation may induce some degenerative effects in the brain by increasing oxidative stress and DNA breakage plus interference with the blood–brain barrier permeability. There are also recent reports on the role of Wi-Fi and mobile phone frequencies on Ca2+ influx through Ca2+ channels. The EMR increases ROS production in the neurons through the activation of oxidant system including NADPH oxidase activity and nitric oxide production. These effects are accompanied by a decrease in brain tissue of enzymatic antioxidants such as superoxide dismutase, catalase, and glutathione peroxidase together with a fall in the levels of nonenzymatic antioxidants such as glutathione and vitamin C.

Cell phone- and Wi-Fi-induced EMR appears to induce degenerative effects through increase of oxidative stress and decrease of antioxidants in the brain that affect neuronal physiological functions. Antioxidants seem to counteract the effects on the EMR, however.

Safe Doses of Wi-Fi in Brain
Most of the studies that have been conducted while investigating the biological effects of Wi-Fi on humans have mainly dealt with the amount of energy absorbed by the human tissue. They are somewhat limited, however, with regard to measurements of the specific absorption rate (SAR). SAR is a rate of energy absorbed by a unit mass of the object and usually expressed by the parameter W/kg2. We may liken the intensity of RF rate to a quantity of novalgin (analgesic) tablets. If, say, there are 100 mg of novalgin per tablet, we cannot decide anything about the efficacy of the tablets unless we also know the amount of the tablets taken, e.g., two tablets taken every 4 h (or 200 mg every 4 h). The amount of a drug absorbed into the body is the main determinant of its effect (Lai and Singh 1996).

There are also ongoing dosimetry studies that measure RF levels around the globe, including that coming from various sources including wireless local area networks (WLANs) which indicate that the associated exposure level is low (Foster and Glaser 2007). Martínez‐Búrdalo and Martin (2009) reported that measuring local energy SAR rates in different areas of the brain in a rat exposed to RF rate revealed that two brain regions that are spaced less than a millimeter apart can have more than a twofold difference in SAR. Martens et al. (1995) also reported that the peak (hot spot) for SAR in the head tissue of a user of a mobile telephone can range from 2–8 W/kg2 per watt output of the device. The peak energy output of mobile telephones can range from 0.6–1 W, although the average output is closer to 0.6 than to 1.0 Studies have shown that neurological damage can be observed at exposure levels of 0.12 mW/kg (Eberhardt et al. 2008). This is less than one eighth of the average exposure level of 1 mW/kg found 150–200 m from a mobile phone mast. The researchers concluded that “the weakest fields are the biologically most harmful.”

Yioultsis et al. (2002) studied the occurrence of considerable differences in electric field or SAR values. They also demonstrated high radiation absorption by the head, which, apart from any possible biological damage, caused a rise in brain temperature after a 10-min exposure. Although both SAR values and the thermal rise in the case of a WLAN are one or two orders of magnitude lower than before exposure, the issue of prolonged exposure is raised, since it is found that the safety limits for long exposure are also marginally violated.
Pinto et al. (2010) studied the dosimetry levels during exposure to the electromagnetic (EM) field associated with the Wi-Fi frequency band (2,412–2,484 MHz).
The exposure system they developed allows experiments to be performed for the evaluation of biological effects of electromagnetic field exposure during early life. They found that average whole-body SAR drastically changes during the exposure period according to the size and weight of the new born mice.

Blood – brain barrier permeability
(b) Blood–brain barrier permeability: It has been known for years that EMR has the potential to alter the permeability of the blood–brain barrier. Salford et al. (2003) and Nittby et al. (2009) report on various studies of the effect of EMR. The danger of a break in the blood–brain barrier is that the brain ceases to be protected from compounds in the blood that are harmful to the nervous system.

Salford et al. (1997) exposed rats to microwave radiation at an intensity equivalent to that received by a mobile phone user. They investigated the ease by which substances toxic to the central nervous system can cross over from the blood into the brain and found that the blood–brain barrier breaks down after a 2-min exposure. They demonstrated consequent neural damage especially in subjects of middle age and deduced that mobile phone use can precipitate degenerative brain effects. In addition, Nittby et al. (2008) and Nittby et al. (2009) and Salford (2007) have found that very low emission energy levels cause more leakage across the blood–brain barrier than higher levels.

Franke et al. (2005) reported that no changes in the blood–brain barrier permeability to sucrose occurred in response to constant exposure, over a period of 1–5 days, to a mobile phone signal at 1,800 MHz. Grafstrom et al. (2008) similarly could find no change in the permeability of the blood–brain barrier to several types of markers and observed no dark neurons or neuronal damage after exposing rats to a mobile phone 900 signal with an SAR of 0.6 or 60 mW/kg for 2 h per week, over a period of 55 weeks. Masuda et al. (2009) observed the passage of plasma protein albumin across the blood–brain barrier and no appearance of dark neurons in experiments. McQuade et al. (2009) observed no effect of a 30-min exposure to modulated GSM 915 MHz (two types of modulation: 217 Hz and 16 Hz) or to a continuous signal (SAR of 0.0018–20 W/kg in male rats). Poulletier De Gannes et al. (2009) also detected no effect on blood–brain barrier integrity or neuronal degeneration. These authors also assessed neuronal apoptosis. Cosquer et al. (2005) observed no effect of semi-chronic exposure to 2.45 GHz pulses (2 μs, 500 Hz) for 45 min per day over 10 days, using neither indirect observations based on cognitive tests nor by the passage of Evans blue dye across the blood–brain barrier (study carried out on 36 male rats). For the cognitive tests, the authors investigated whether radio frequency modified the behavioral response of the animals to the injection of a muscarinic antagonist (scopolamine) that crosses the blood–brain barrier only poorly. The response of the cage control rats differed from those seen in the sham-exposed and exposed rats (effect of stress), despite habituation to handling before testing.

We have reviewed the literature to better understand the effects of Wi-Fi on human health, especially on brain neural activity. Wi-Fi may affect cell function via nonthermal effects. The EMR exposure can increase ROS formation and decrease cognitive function and antioxidant values by second messengers that cause increases in the activity of plasma membrane NADH oxidase and PKC activation. Prolonged exposure to EMR can also damage DNA which may accelerate neuronal cell death. Ca2+ is important in neuronal cells for physiological function and pathophysiological function such as cell proliferation and apoptosis. The results from relatively few recent papers indicate that Ca2+ influx is increased in neuronal cells through the activation of TRP channels and VGCC following EMR exposure. Future studies should therefore be aimed at identifying the specific intracellular pathways and calcium channels that transduce Wi-Fi-induced changes in calcium influx into signal capabilities of exposed brain and neurons.


Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley

Electromagnetic Radiation Safety

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