Study type: Medical/biological study (experimental study)

Clinical significance of different effects of static and pulsed electromagnetic fields on human osteoclast cultures. med./bio.

Published in: Rheumatol Int 2012; 32 (4): 1025-1031

Aim of study (acc. to author)

To study whether static magnetic fields that are generated around spinal metal (titanium) devices could influence periprosthetic osteolysis modulating not only osteoblasts but also osteoclast cells function. Additionally, it was investigated whether pulsed electromagnetic fields that are usually used in clinical practice for nonunions could affect osteoclasts differentiation and activity.

Background/further details

Primary osteoclast cells were isolated from primary human osteoclast precursor cells.

Endpoint

Exposure

Exposure Parameters
Exposure 1:
Exposure duration: continuous for 7, 10 or 14 days
Exposure 2: 50 Hz
Exposure duration: continuous for 7, 10 or 14 days

Exposure 1

Main characteristics
Frequency
Type
Exposure duration continuous for 7, 10 or 14 days
Exposure setup
Exposure source
  • not specified
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.9 µT - - - -

Exposure 2

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for 7, 10 or 14 days
Exposure setup
Exposure source
Setup 30 cm long solenoid with a diameter of 15 cm and 45 turns of 20 gauge magnetic wire placed in an incubator with 100% humidity and a temperature of 37°C; field uniform inside the solenoid
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 0.4 mT - - - -

Reference articles

  • Denaro V et al. (2008): Static electromagnetic fields generated by corrosion currents inhibit human osteoblast differentiation.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The static magnetic field-exposed cells showed a more differentiated phenotype, a higher number of differentiated cells and a significantly higher TRAP enzyme activity after 7 and 10 days of exposure with respect to a sham exposed cells. Pulsed electromagnetic field exposed cells have a less-differentiated phenotype after 7 days of exposure compared with the relative sham exposed control (no difference after 10 and 14 days), while the TRAP enzyme activity showed no statistically significant differences between exposed and control cells at any observation time.
The findings indicated that static magnetic fields of the same intensity of the one generated around spinal devices can affect osteoclast cell differentiation and activity. Aseptic loosening around titanium implants might be due in part to an increased osteoclast activity and cell differentiation. Pulsed electromagnetic fields of the same intensity than the one used for the management of nonunions can affect osteoclasts phenotype after 7 days of exposure, while osteoclasts TRAP enzyme activity is not affected by this kind of electromagnetic fields.

Study character:

Study funded by

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