Static electromagnetic fields generated by corrosion currents inhibit human osteoblast differentiation.
METHODS
Human osteoblast cultures were exposed to a very low intensity static magnetic fields (SMF) to investigate its effects on osteoblast growth and differentiation.


OBJECTIVE
Analysis of the effects of periprosthetic SMF on the growth and differentiation of human osteoblast cell cultures in vitro.


BACKGROUND
The effects of pulsed electromagnetic fields (PEMF) on cell proliferation, especially in human osteoblast-like cells is well described, whereas few data are available on the effects of SMF on osteoblast cell culture. We previously demonstrated that the proliferation of human osteoblast cultures is reduced when cells are exposed to a continuous low intensity SMF comparable to the one that occurs around metal devices (Ti spinal implant) because of the generation of electric currents between the screw (Ti6Al4V) and the rod (Ti).


METHODS
Primary osteoblastic cells were isolated from a human femoral head. Osteoblast cultures were exposed to SMF and alkaline phosphatase activity was evaluated in the osteoblast cell cultures at different time points. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to evaluate mRNA expression levels of osteocalcin, Runx2, and collagen I genes.


RESULTS
The SMF-treated cells showed a progressive increase in the alkaline phosphatase activity which, however, remained always lower than the one observed in the control group at each observation time (72 hours, 7 and 14 days). RT-PCR demonstrated that Runx2 and collagen I mRNA were downregulated following SMF stimulation, whereas no change in osteocalcin mRNA was observed.


CONCLUSIONS
Continuous low-intensity electromagnetic field comparable to the one that generates around metal devices because of the generation of corrosion currents inhibits osteoblasts differentiation pattern and might contribute at least in part to a decrease in periprosthetic bone formation occurring in vivo.
Denaro
Vincenzo
V
Department of Orthopaedic and Trauma Surgery, Campus Biomedico University, Catholic University, Rome, Italy.
Cittadini
Achille
A
Barnaba
Simona A
SA
Ruzzini
Laura
L
Denaro
Luca
L
Rettino
Alessandro
A
De Paola
Barbara
B
Papapietro
Nicola
N
Sgambato
Alessandro
A
D000469:Alkaline Phosphatase / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000528:radiation effects*; D002478:Cells, Cultured; D024042:Collagen Type I / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000378:metabolism; D003343:Corrosion; D004574:Electromagnetic Fields; D005269:Femur / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D006801:Humans; D010006:Osteoblasts / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D015675:Osteocalcin / Q000378:metabolism; D019736:Prostheses and Implants / Q000009:adverse effects; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014158:Transcription, Genetic / Q000528:radiation effects
D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D012333:RNA, Messenger; C493709:RUNX2 protein, human; D015675:Osteocalcin; D014025:Titanium; D000469:Alkaline Phosphatase