Skeletal muscle mitochondrial capacity in people with multiple sclerosis

Background: People with multiple sclerosis (MS) have functional disability and may have reduced muscle mitochondrial capacity.

Objective: The objective of this paper is to measure muscle mitochondrial capacity of leg muscles using near-infrared spectroscopy (NIRS) and compare to functional status.

Materials and methods: People with MS (n = 16) and a control (CON) group (n = 9) were evaluated for 25-ft walk time. Mitochondrial capacity of both gastrocnemius muscles were measured with NIRS as the rate of recovery of oxygen consumption in after exercise.

Results: Mitochondrial capacity was lower in the MS group compared to the CON group (rate constants: 1.13 ± 0.29 vs. 1.68 ± 0.37 min^-1, p < 0.05). There was a tendency for people with MS who used assistive devices to have lower mitochondrial capacity in the weaker leg (p = 0.07).

Conclusion: NIRS measurements of mitochondrial capacity suggest a 40% deficit in people with MS compared to CONs and this may contribute to walking disability.