Effects of moderate intensity static magnetic fields on human bone marrow‐derived mesenchymal stem cells

Abstract

This study aimed to explore effects of static magnetic fields (SMFs) of moderate intensity (3-50 mT) as biophysical stimulators of proliferation and osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs). MSCs were exposed to SMFs of three intensities: 3, 15, and 50 mT. Proliferation was assessed by cell counting and bromodeoxyuridine incorporation, and differentiation by measuring alkaline phosphatase (ALP) activity, calcium content, mineralized nodule formation, and transcripts of osteogenic markers. Moderate intensity SMFs increased cell proliferation, ALP activity, calcium release, and mineralized nodule formation in a dose- and time-dependent manner, which peaked at 15 mT. In the same manner, they upregulated expression of osteogenic marker genes such as ALP, bone sialoprotein 2 (BSP2), collagen1a1 (COL1a1), osteocalcin (OCN), osteonectin (ON), osteopontin (OPN), osterix (OSX), and runt-related transcription factor 2 (RUNX2) with peak at 15 mT after 14 or 21 days of exposure. Results demonstrate that moderate intensity SMFs promote proliferation and osteoblastic differentiation of MSCs. This effect could help to improve MSC responses during osseointegration between a dental implant and surrounding bone.

Magnetic targeting as a strategy to enhance therapeutic effects of mesenchymal stromal cells

“…To date, reports of SMF use with MSCs have demonstrated that moderate SMFs can have divergent effects (enhancing or inhibiting) on MSC viability [19, 45], proliferation [45–47], differentiation capacity [19, 31, 47, 48], colony formation [31], and extracellular vesicle secretion [19, 46] (summarized in Table 2 and Fig. 2).…”

Enhanced osteogenic differentiation of human bone–derived mesenchymal stem cells in 3‐dimensional printed porous titanium scaffolds by static magnetic field through up‐regulating Smad4

“…Conversely, the positive effect of SMF (3–50 mT) on BMSCs has also been reported by Kim et al . (21). Until now, the resulting effect was considered to be associated with the cell type, time of exposure, and initial cell densities (22, 23).…”

Effects of moderate intensity static magnetic fields on osteoclastic differentiation in mouse bone marrow cells

“…A magnet was placed horizontally below the wells, and the north (N) side of magnet was oriented towards the well. We selected the same SMF intensities that were found to stimulate osteogenic differentiation in MSCs [Kim et al, ] and periodontium‐derived cells [Kim et al, ] in our previous studies. The SMFs were established by controlling the distance between the magnet and culture plates, as previously described [Kim et al, ; Kim et al, ].…”

“…We previously demonstrated that 15 mT intensity SMF, which is a relatively weak intensity among moderate SMF intensity ranges (1 mT–1 T), can trigger earlier peri‐implant bone formation than the absence of a magnetic field in vivo [Leesungbok et al, ; Kim et al, ]. Moreover, we demonstrated that 15 mT intensity SMFs could enhance the proliferation and osteogenic differentiation of human bone marrow‐derived mesenchymal stem cells (MSCs) [Kim et al, ] and periodontium‐derived cells, such as osteoblasts, cementoblasts, and periodontal ligament cells [Kim et al, ] in vitro. As osteoblastic stromal cells in physiological conditions modulate osteoclastogenesis and osteoclastic bone resorption [Takahashi et al, ], it is assumed that SMF‐induced osteogenic differentiation in osteoblasts would also affect osteoclasts.…”