The treatment of osteoporosis by pulsed electromagnetic field

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Osteoporosis is a metabolic bone disease characterized by low bone mass and impaired bone microstructure leading to increased bone fragility and susceptibility to fracture.  Long-term use of medication will not only bring the adverse effects of medication, but also  reduce the compliance of medication. Physiotherapy is a non-invasive treatment that is safer than medication. As a commonly used physical therapy, pulsed electromagnetic field (PEMF) has been approved by FDA in 1979 for the treatment of post-fracture osteoarthritis . Meanwhile, PEMF has the effects of reducing pain, enhancing bone quality and improving the functional prognosis of patients, and is an effective physical therapy[1].

Currently, the intensity and frequency of PEMF used in different clinical studies vary, with the intensity and frequency ranging from 0.2 to 120 mT and 1 to 100 Hz, respectively. The majority of clinical studies have used PEMF with intensities ranging from 0.2 to 20 mT and frequencies ranging from 5 to 50 Hz. Clinically, there are no comparative studies of PEMF at different intensities or frequencies for the treatment of osteoporosis. For example, Wang et al [2] used PEMF with an intensity of 1.6 mT and frequencies of 8, 50, and 75 Hz to expose ovariectomized (OVX) mice for 4 weeks, and the results showed that the deterioration of bone structure in OVX mice was significantly attenuated by PEMF with an intensity of 50 and 75 Hz, whereas there was no significant effect of 8 Hz. Therefore, the choice of frequency and intensity of PEMF is important in clinical applications, and different frequencies and intensities may produce different therapeutic effects [3].

The duration of PEMF treatment of osteoporosis patients in different studies ranged from 10 to 60 min each time, once a day, for a total of 10 to 60 treatments, lasting between 14 and 180 d.

The most commonly used treatment regimen is 40 min per session, with 10 sessions per course, 1 session per day for the first course, 1 session every other day for the second course, and 1 session every 2 days for the third course, lasting approximately 2 months [4].

It was suggestted that PEMF may regulate the functions of osteoblasts and osteoclasts by regulating the Wnt/β-Catenin RANKL/OPG signaling pathway, thereby preventing bone loss and increasing bone mass. RANKL plays an important role in Wnt/β-catenin differentiation and is an important pathway for regulating proliferation and metabolism in osteoblasts [5]. RANKL binds to RANK on the surface of osteoclasts and promotes osteoclast differentiation and activation, while OPG can competitively inhibit the binding of RANKL to RANK for inhibiting osteoclast function. In a clinical study, Catalano et al [6] found that after 30 d of PEMF treatment, the serum BALP and β-catenin levels of PMOP patients increased significantly, and the RANKL/OPG ratio decreased significantly. After 60 d of treatment, serum BALP and β-catenin levels increased significantly, while CTX and RANKL levels decreased significantly, indicating that PEMF may regulate bone metabolism by regulating the RANKL/OPG and Wnt/β-Catenin signaling pathways.

It was also found that PEMF treatment decreased serum PTH levels and increased serum serum 25(OH)D2 and 25(OH)D3 levels in patients with PMOP. In another study, the combination of PEMF and calcitonin in patients with spinal cord injury-induced osteoporosis also showed a significant decrease in serum PTH levels after treatment. And 1,25-(OH)2D3 levels were significantly increased. These results suggest that PEMF may increase BMD through the regulation of PTH secretion and VD metabolism and play a role in the treatment of osteoporosis[7].

Reference:

  1. Caliogna L, Medetti M, Bina V, Brancato AM, Castelli A, Jannelli E, Ivone A, Gastaldi G, Annunziata S, Mosconi M, Pasta G. Pulsed Electromagnetic Fields in Bone Healing: Molecular Pathways and Clinical Applications. Int J Mol Sci. 2021 Jul 9;22(14):7403.

  2. Wang L, Li Y, Xie S, Huang J, Song K, He C. Effects of Pulsed Electromagnetic Field Therapy at Different Frequencies on Bone Mass and Microarchitecture in Osteoporotic Mice. Bioelectromagnetics. 2021 Sep;42(6):441-454.

  3. Daish C, Blanchard R, Fox K, Pivonka P, Pirogova E. The Application of Pulsed Electromagnetic Fields (PEMFs) for Bone Fracture Repair: Past and Perspective Findings. Ann Biomed Eng. 2018 Apr;46(4):525-542.

  4. Li S, Jiang H, Wang B, Gu M, Bi X, Yin Y, Wang Y. Magnetic Resonance Spectroscopy for Evaluating the Effect of Pulsed Electromagnetic Fields on Marrow Adiposity in Postmenopausal Women With Osteopenia. J Comput Assist Tomogr. 2018 Sep/Oct;42(5):792-797.

  5. Song S, Guo Y, Yang Y, Fu D. Advances in pathogenesis and therapeutic strategies for osteoporosis. Pharmacol Ther. 2022 Sep;237:108168.

  6. Catalano A, Loddo S, Bellone F, Pecora C, Lasco A, Morabito N. Pulsed electromagnetic fields modulate bone metabolism via RANKL/OPG and Wnt/β-catenin pathways in women with postmenopausal osteoporosis: A pilot study. Bone. 2018 Nov;116:42-46.

  7. Wang L, Xie S, Zhu S, Gao C, He C. Efficacy of Pulsed Electromagnetic Fields on Experimental Osteopenia in Rodents: A Systematic Review. Bioelectromagnetics. 2021 Jul;42(5):415-431.