Reference: Pulsed Electromagnetic Fields for Clinical Applications, Edited by
Marko S. Markov, James T. Ryaby, and Erik I. Waldorff, CRC Press 2020
International Standard Book Number-13: 978-0-367-17971-7 (Hardback)
PEMF dosimetry at the adenosine receptor and inflammation .
Adenosine is a building block for RNA/DNA and a part of the energy molecule ATP (Chen et al., 2013). In addition, adenosine is a signaling molecule. Adenosine acts through four types of ARs – A1, A2A, A2B, and A3. These receptors are widely distributed throughout the body and have been found to be part of both physiologi- cal and pathological biological functions. They affect, at the least, cardiac rhythm and circulation, breakdown of fat, kidney blood flow, immune function, regulation of sleep, development of new blood vessels, inflammatory diseases/inflammation, blood flow, and neurodegenerative disorders.
The role of ARs (adenosine receptors) and adenosine in modifying inflammation is well accepted (Varani et al., 2017). Neutrophils have a major role in inflammation. There are A2A receptors in the membranes of neutrophils. PEMFs applied in vitro at the surface of neutrophils have been found to significantly increase the binding of adenosine to the A2A receptor in the human neutrophils exposed to PEMFs. This effect was time, intensity, and temperature dependent. PEMF dose-response studies found that a PEMF effect was detectable after 30min of exposure, and the receptors became saturated with a 1.5 mT magnetic field (Massari et al., 2007). The effect plateaued with intensities >1.5 mT.
The PEMF used had an intensity range from 0.1 to 4.5 mT, frequency range from 10 to 120Hz. The signal had a pulse duration of 1.3 ms, frequency of 75Hz, 10% duty cycle. The most used peak intensity of the magnetic field was 1.5 mT. The cor- responding peak amplitude of the induced electric voltage was 2.0 ± 0.5 mV.
Armed with this information, the clinician might reasonably assume that a 1.5 mT “dose” for at least 30 minutes at the inflammatory target tissue would be the opti- mized amplitude of a magnetic field to help with reducing inflammation, at least as far as neutrophil involvement is concerned. The clinician is faced routinely with the need to reduce inflammation at various depths in the body, depending on the target organ and tissue, and it is not unreasonable to consider the role of the AR on the neutrophil membrane as a worthy and useful approach.
