Effects of the pulsed electromagnetic field PST® on human tendon stem cells: a controlled laboratory study

Abstract

BackgroundCurrent clinical procedures for rotator cuff tears need to be improved, as a high rate of failure is still observed. Therefore, new approaches have been attempted to stimulate self-regeneration, including biophysical stimulation modalities, such as low-frequency pulsed electromagnetic fields, which are alternative and non-invasive methods that seem to produce satisfying therapeutic effects. While little is known about their mechanism of action, it has been speculated that they may act on resident stem cells. Thus, the purpose of this study was to evaluate the effects of a pulsed electromagnetic field (PST®) on human tendon stem cells (hTSCs) in order to elucidate the possible mechanism of the observed therapeutic effects.MethodshTSCs from the rotator cuff were isolated from tendon biopsies and cultured in vitro. Then, cells were exposed to a 1-h PST® treatment and compared to control untreated cells in terms of cell morphology, proliferation, viability, migration, and stem cell marker expression.ResultsExposure of hTSCs to PST® did not cause any significant changes in proliferation, viability, migration, and morphology. Instead, while stem cell marker expression significantly decreased in control cells during cell culturing, PST®-treated cells did not have a significant reduction of the same markers.ConclusionsWhile PST® did not have significant effects on hTSCs proliferation, the treatment had beneficial effects on stem cell marker expression, as treated cells maintained a higher expression of these markers during culturing. These results support the notion that PST® treatment may increase the patient stem cell regenerative potential.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1261-3) contains supplementary material, which is available to authorized users.

Chemical Activation of the Hypoxia-Inducible Factor Reversibly Reduces Tendon Stem Cell Proliferation, Inhibits Their Differentiation, and Maintains Cell Undifferentiation

“…The medium was changed every 2-3 days. All experiments were carried out with cells at passage four to six after isolation [ 17 ].…”

“…All photomicrographs were acquired with an Axiovert 40 microscope (Zeiss) equipped with a Moticam 2300 camera (Motic). The mRNA expression of adipogenic markers including PPAR- γ and LPL were also assessed on days 7 and 21 by real-time PCR, as described above [ 17 ].…”

Magnetotherapy: The quest for tendon regeneration

“…Surprisingly, TSPCs electromagnetically stimulated (30 Hz, 1.5 mT) for 60 min presented a similar migratory profile compared to unexposed cells (Randelli et al, ). In this study, authors also reported that electromagnetic stimulation is likely to maintain TSPCs in an undifferentiated state by regulating stem cell reprogramming factors octamer‐binding transcription factor 4 (Oct4), Kruppel‐like factor 4 (KLF4) and Nanog, up to 48 hr following stimulation (Randelli et al, ).…”

“…Surprisingly, TSPCs electromagnetically stimulated (30 Hz, 1.5 mT) for 60 min presented a similar migratory profile compared to unexposed cells (Randelli et al, ). In this study, authors also reported that electromagnetic stimulation is likely to maintain TSPCs in an undifferentiated state by regulating stem cell reprogramming factors octamer‐binding transcription factor 4 (Oct4), Kruppel‐like factor 4 (KLF4) and Nanog, up to 48 hr following stimulation (Randelli et al, ). In a different study, tendon‐derived cells stimulated with low‐frequency static magnetic field (2 Hz, 350 mT) had enhanced expression of COL1A1, TNC, DCN, and SCX after a single exposure for 8 hr (Pesqueira, Costa‐Almeida, & Gomes, ).…”

Bioreactors for Stem Cell Expansion and Differentiation

“…The use of magnetic forces in tissue healing is quite recent and some pioneer studies suggest the in uence of magnetic elds in modulating tendon injury recovery after rat Achilles transection (Strauch et al 2006). Besides pain relief (Nelson eta l. 2013) and stimulation of blood circulation, magnetotherapy has been reported to stimulate tendon cell proliferation (Seeliger et al 2014, Randelli et al 2016 in the promotion of the healing process.…”