Effects and Mechanisms of Exogenous Electromagnetic Field on Bone Cells: A Review

Abstract

Osteoporosis, fractures, and other bone diseases or injuries represent serious health problems in modern society. A variety of treatments including drugs, surgeries, physical therapies, etc. have been used to prevent or delay the progression of these diseases/injuries with limited effects. Electromagnetic field (EMF) has been used to non-invasively treat bone diseases, such as fracture and osteoporosis, for many years. However, because a variety of cellular and molecular events can be affected by EMF with various parameters, the precise bioeffects and underlying mechanisms of specific EMF on bone cells are still obscure. Here, we summarize the common therapeutic parameters (frequency and intensity) of major types of EMF used to treat bone cells taken from 32 papers we selected from the PubMed database published in English from 1991 to 2018. Briefly, pulse EMF promotes the proliferation of osteoblasts when its frequency is 7.5-15 Hz or 50-75 Hz and the intensity is 0.40-1.55 mT or 3.8-4 mT. Sinusoidal EMF, with 0.9-4.8 mT and 45-60 Hz, and static magnetic field with 0.1-0.4 mT or 400 mT, can promote osteoblast differentiation and maturation. Finally, we summarize the latest advances on the molecular signaling pathways influenced by EMF in osteoblasts and osteoclasts. A variety of molecules such as adenosine receptors, calcium channels, BMP2, Notch, Wnt1, etc., can be influenced by EMF in osteoblasts. For osteoclasts, EMF affects RANK, NF-κB, MAPK, etc. We speculate that EMF with different frequencies and intensities exert distinct bioeffects on specific bone cells. More high-quality work is required to explore the detailed effects and underlying mechanisms of EMF on bone cells/skeleton to optimize the application of EMF on bone diseases/injuries.

Pulsed Electromagnetic Fields in Bone Healing: Molecular Pathways and Clinical Applications

“…Furthermore, activation of PI3K/Akt signaling in MSCs under PEMFs osteogenic induction has been reported. Zhang and colleagues described increased levels of phosphorylated Akt, phosphorylated GSK3β, and nuclear β-catenin, indicating the Akt/GSK3β/β-catenin axis is involved in osteogenic differentiation, following PEMF exposure [ 28 ]. The involvement of Akt has been reported also by Poh and colleagues, who demonstrated that after PEMFs exposure at selected parameters, the activation of Akt in adipose derived mesenchymal stem cells, leads to a significant upregulation of bone-specific genes [ 29 ].…”

Effect of acetone and methanol environment on the electrical properties of Fe doped hydroxyapatite

“…Sensing of methanol, ethanol, acetone, and ammonia is reported in literature by HAP and measured by electrical properties 11‐15 . Sensing of 1000 ppm CO and CO 2 gases using Fe doped HAp thick films have been reported by Mene et al with 91% and 112% response at temperature 140°C and 155°C, respectively 10 . Anjum et.…”

“…Hydroxyapatite, collagen, and fluids are major components of bone. Selective use of dielectric and electric properties of HAp can play a very important role to improve (a) hydroxyapatite's bioactivity with electric poling (b) bone growth with electrical stimulation for bone grafts in spinal fusion (c) healing and repairing of bone fractures with electric field and (d) osteonecrosis and osteoarthritis treatment 5‐10 …”

“…Selective use of dielectric and electric properties of HAp can play a very important role to improve (a) hydroxyapatite's bioactivity with electric poling (b) bone growth with electrical stimulation for bone grafts in spinal fusion (c) healing and repairing of bone fractures with electric field and (d) osteonecrosis and osteoarthritis treatment. [5][6][7][8][9][10] Hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 ] crystallize in P 6 3 /m space group. It has OH ions and these are located at the center of Ca 2+ triangles situated along the c-axis in hexagonal unit cell of hydroxyapatite.…”

“…[11][12][13][14][15] Sensing of 1000 ppm CO and CO 2 gases using Fe doped HAp thick films have been reported by Mene et al with 91% and 112% response at temperature 140°C and 155°C, respectively. 10 Anjum et. al have reported the sensing of alcohols using nanocomposite thick film of graphite and HAp with response 465% (for 100 ppm methanol) at 30°C.…”