Spinal Cord Injury-Induced Osteoporosis: Pathogenesis and Emerging Therapies

Curr Osteoporos Rep, 2012 · DOI: 10.1007/s11914-012-0117-0 · Published: December 1, 2012

Spinal Cord Injury Musculoskeletal Medicine

Simple Explanation

Spinal cord injuries can lead to rapid and severe bone loss, increasing the risk of fractures. This happens because the bones are no longer loaded mechanically due to paralysis. This lack of mechanical loading causes bone cells to produce more sclerostin, which inhibits bone formation and indirectly stimulates bone breakdown. Currently, there are no established guidelines to prevent this bone loss. Researchers are exploring new treatments like anti-sclerostin antibodies, electrical stimulation to load the lower extremities, and vibration therapy to help prevent or treat this SCI-induced osteoporosis.

Study Duration

Not specified

Participants

155 men with varying degrees of SCI, 49 subjects with varying degrees of chronic SCI, 39 men with chronic SCI and 10 men with no SCI

Evidence Level

Review article

Key Findings

1
Sclerostin is a key mediator in SCI-induced bone loss. Initially, sclerostin levels increase after SCI due to mechanical unloading, leading to reduced bone formation.
2
However, in chronic SCI, sclerostin levels decrease as rapid bone loss progresses, making it a potential biomarker of osteoporosis severity in the long term.
3
Obesity, which is more common in SCI, does not protect against bone loss in this population, suggesting that increased fat mass may contribute to BMD loss.

Research Summary

Spinal cord injury (SCI) leads to rapid and severe osteoporosis with increased fracture risk due to mechanical unloading and increased sclerostin expression. Sclerostin plays a dual role, acting as a mediator of acute bone loss and a biomarker of osteoporosis severity in chronic SCI. Emerging therapies such as anti-sclerostin antibodies, mechanical loading with electrical stimulation, and vibration therapy show promise in preventing or treating SCI-induced osteoporosis.

Practical Implications

Therapeutic Target Identification

Sclerostin is identified as a potential therapeutic target to prevent rapid immobility-induced bone loss in acute SCI.

Biomarker Development

Sclerostin can be used as a biomarker of osteoporosis severity in chronic SCI.

Emerging Treatment Strategies

Mechanical loading of the lower extremity with electrical stimulation and mechanical stimulation via vibration therapy can be used for treatment.

Study Limitations

1
Lack of standard clinical guidelines for diagnosis, prevention, or treatment of SCI-induced osteoporosis
2
Limited information regarding the natural course of SCI-induced bone loss
3
Need for larger longitudinal studies to establish the efficacy of emerging therapies like ES and FES

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