Distinct Genomic Expression Signatures after Low-Force Electrically Induced Exercises in Persons with Spinal Cord...

Area of Science:

• Exercise Physiology
• Molecular Biology
• Neurorehabilitation

Background:

• Spinal cord injury (SCI) leads to metabolic dysfunction and insulin resistance in skeletal muscle.
• Electrical muscle stimulation (EMS) is a potential therapy for SCI, but high-intensity contractions risk fractures.

Purpose of the Study:

• Investigate acute molecular responses to different EMS frequencies (3 Hz vs. 1 Hz) in individuals with SCI.
• Determine optimal EMS parameters to improve muscle phenotype without compromising skeletal integrity.

Main Methods:

• Ten individuals with complete SCI underwent unilateral EMS (1-hour at 3 Hz or 3-hour at 1 Hz).
• Vastus lateralis muscle biopsies were collected post-exercise.
• Genomic and epigenomic expression profiles were analyzed.

Main Results:

• 3 Hz EMS induced significant upregulation of early response genes (e.g., NR4A3, PGC-1α, MYC) involved in mitochondrial biogenesis and metabolism.
• Gene expression changes indicate enrichment of pathways for signal transduction, cellular response, and metabolism.
• 1 Hz EMS showed similar trends but did not reach statistical significance; no significant methylation changes were observed.

Conclusions:

• A 1-hour, 3 Hz EMS session provides a suitable low-force stimulus for acute genomic response in paralyzed muscle.
• This EMS protocol may improve the metabolic and contractile characteristics of skeletal muscle in individuals with chronic paralysis.
• Regularly performed 3 Hz EMS could be a safe and effective therapeutic strategy for SCI-related metabolic dysfunction.