Sinusoidal electromagnetic fields accelerate bone regeneration by boosting the multifunctionality of bone marrow mesenchymal stem cells.

Abstract

BACKGROUND: The repair of critical-sized bone defects is always a challenging problem. Electromagnetic fields (EMFs), used as a physiotherapy for bone defects, have been suspected to cause potential hazards to human health due to the long-term exposure. To optimize the application of EMF while avoiding its adverse effects, a combination of EMF and tissue engineering techniques is critical. Furthermore, a deeper understanding of the mechanism of action of EMF will lead to better applications in the future. METHODS: In this research, bone marrow mesenchymal stem cells (BMSCs) seeded on 3D-printed scaffolds were treated with sinusoidal EMFs in vitro. Then, 5.5 mm critical-sized calvarial defects were created in rats, and the cell scaffolds were implanted into the defects. In addition, the molecular and cellular mechanisms by which EMFs regulate BMSCs were explored with various approaches to gain deeper insight into the effects of EMFs. RESULTS: The cell scaffolds treated with EMF successfully accelerated the repair of critical-sized calvarial defects. Further studies revealed that EMF could not directly induce the differentiation of BMSCs but improved the sensitivity of BMSCs to BMP signals by upregulating the quantity of specific BMP (bone morphogenetic protein) receptors. Once these receptors receive BMP signals from the surrounding milieu, a cascade of reactions is initiated to promote osteogenic differentiation via the BMP/Smad signalling pathway. Moreover, the cytokines secreted by BMSCs treated with EMF can better facilitate angiogenesis and osteoimmunomodulation which play fundamental roles in bone regeneration. CONCLUSION: In summary, EMF can promote the osteogenic potential of BMSCs and enhance the paracrine function of BMSCs to facilitate bone regeneration. These findings highlight the profound impact of EMF on tissue engineering and provide a new strategy for the clinical treatment of bone defects.

AI evidence extraction

Main findings

BMSC-seeded scaffolds treated with sinusoidal EMFs accelerated repair of critical-sized calvarial defects in rats. EMF did not directly induce BMSC differentiation but increased sensitivity to BMP signals by upregulating specific BMP receptors, promoting osteogenic differentiation via BMP/Smad signalling; EMF-treated BMSCs also secreted cytokines that better facilitated angiogenesis and osteoimmunomodulation.

Outcomes measured

• Bone regeneration/repair of critical-sized calvarial defects
• BMSC osteogenic differentiation via BMP/Smad signalling
• BMP receptor expression/sensitivity to BMP signals
• Angiogenesis facilitation (paracrine cytokines)
• Osteoimmunomodulation (paracrine effects)

Limitations

• EMF exposure parameters (e.g., frequency, intensity, duration) not provided in the abstract
• Sample size not reported in the abstract
• Animal model and in vitro findings; human clinical relevance not established in the abstract

{
    "study_type": "animal",
    "exposure": {
        "band": null,
        "source": "therapeutic EMF (sinusoidal)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Rats with 5.5 mm critical-sized calvarial defects; bone marrow mesenchymal stem cells (BMSCs) on 3D-printed scaffolds (in vitro and implanted)",
    "sample_size": null,
    "outcomes": [
        "Bone regeneration/repair of critical-sized calvarial defects",
        "BMSC osteogenic differentiation via BMP/Smad signalling",
        "BMP receptor expression/sensitivity to BMP signals",
        "Angiogenesis facilitation (paracrine cytokines)",
        "Osteoimmunomodulation (paracrine effects)"
    ],
    "main_findings": "BMSC-seeded scaffolds treated with sinusoidal EMFs accelerated repair of critical-sized calvarial defects in rats. EMF did not directly induce BMSC differentiation but increased sensitivity to BMP signals by upregulating specific BMP receptors, promoting osteogenic differentiation via BMP/Smad signalling; EMF-treated BMSCs also secreted cytokines that better facilitated angiogenesis and osteoimmunomodulation.",
    "effect_direction": "benefit",
    "limitations": [
        "EMF exposure parameters (e.g., frequency, intensity, duration) not provided in the abstract",
        "Sample size not reported in the abstract",
        "Animal model and in vitro findings; human clinical relevance not established in the abstract"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "electromagnetic fields",
        "sinusoidal EMF",
        "bone regeneration",
        "critical-sized calvarial defect",
        "rats",
        "bone marrow mesenchymal stem cells",
        "BMSCs",
        "3D-printed scaffolds",
        "BMP receptors",
        "BMP/Smad signalling",
        "angiogenesis",
        "osteoimmunomodulation",
        "tissue engineering"
    ],
    "suggested_hubs": []
}

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