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Type IV collagen and its degradation in paralyzed human muscle: effect of functional electrical stimulation
S O Koskinen1, M Kjaer, T Mohr
1Neuromuscular Research Center, Department of Biology, University of Jyväskylä, Jyväskylä, Finland.
Abstract:
The purpose of this study was to evaluate the effects of spinal cord injury (SCI) and functional electrical stimulation (FES) of paralyzed muscles on type IV collagen content and proteins involving its degradation, which is initiated by matrix metalloproteinase (MMP)-2 and -9 and regulated by their tissue inhibitors (TIMPs)-2 and -1. Ten SCI subjects participated in an 18-month program of functional electrical stimulation (FES) of their leg muscles. Needle biopsies were taken from the vastus lateralis muscle before and at various times during the training period, and from able-bodied controls. Type IV collagen concentration was unaltered. ProMMP-2 level of SCI subjects before the training period tended to be higher than able-bodied controls and was significantly above the control level after FES. MMP-9 concentration was unchanged. The results suggest accelerated type IV collagen turnover in skeletal muscle of SCI individuals especially after FES as a part of adaptive process of the muscle.
Insights
Spinal cord injury (SCI) affects muscle proteins. Functional electrical stimulation (FES) in SCI individuals may accelerate type IV collagen turnover in leg muscles, suggesting an adaptive response.
Area of Science:
- Biomedical Engineering
- Muscle Physiology
- Connective Tissue Metabolism
Background:
- Spinal cord injury (SCI) leads to muscle paralysis and atrophy.
- Skeletal muscle in SCI individuals undergoes changes in extracellular matrix composition.
- Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play a role in collagen remodeling.
Purpose of the Study:
- To investigate the impact of SCI and functional electrical stimulation (FES) on type IV collagen content.
- To assess the levels of MMP-2, MMP-9, TIMP-2, and TIMP-1 in the skeletal muscle of SCI individuals undergoing FES.
- To understand the adaptive processes in skeletal muscle following SCI and FES.
Main Methods:
- Muscle biopsies were obtained from the vastus lateralis of ten SCI subjects and able-bodied controls.
- Subjects underwent an 18-month FES program for paralyzed leg muscles.
- Analysis included quantification of type IV collagen, proMMP-2, MMP-9, TIMP-2, and TIMP-1.
Main Results:
- Type IV collagen concentration remained unchanged in SCI subjects post-FES compared to baseline.
- ProMMP-2 levels were elevated in SCI subjects before FES and significantly increased after FES compared to controls.
- MMP-9 concentrations did not show significant changes.
Conclusions:
- FES may accelerate type IV collagen turnover in the skeletal muscle of individuals with SCI.
- This accelerated turnover appears to be an adaptive response of the muscle to FES.
- The study highlights the role of MMP-2 in muscle adaptation post-SCI and FES.