PR Newswire
11/14/05, 10:11a
(Copyright 2005, PR Newswire)

BOSTON, Nov 14, 2005 /PRNewswire via COMTEX/ -- Scientists from Harvard Medical School and Mouse Specifics, Inc. (MSI) presented new data regarding "athletic" gait in the early stages of amyotrophic lateral sclerosis (ALS) in genetically modified mice. Eventually, however, the disease progressed and the mice became paralyzed and died. The new findings in this model indicate that presymptomatic heightened motor function and motor coordination could occur early in ALS, and open new lines of thinking for prevention and treatment of the disease. The results of the study were presented yesterday at "Neuroscience 2005", the 35th Annual Meeting of the Society for Neuroscience in Washington, DC.

The scientists examined gait in SOD1 G93A mice, a widely studied animal model of ALS, the most common and inevitably fatal human neurodegenerative disease. The researchers performed sophisticated gait analyses in these mice. Gait analysis is the process of quantification and interpretation of locomotion. In humans, gait is analyzed to quantify patients' movement disorders to provide diagnosis and treatment options. The researchers expected to identify relevant gait disturbances in SOD1 G93A mice engineered to develop ALS. Paradoxically, however, they discovered that stride length was significantly longer in adult ALS mice just prior to the deterioration of motor performance, paralysis, and death. Increased stride length is often associated with increased amplitude of the electromyogram activity, enhanced motor performance, and "athleticism". Interestingly, a higher incidence of amyotrophic lateral sclerosis has been reported among athletes.

The scientists used a high speed digital imaging system and a recently patented treadmill (The DigiGait(TM) Imaging System) to quantify gait indices in the ALS mice. The anticipated gait disturbances did become apparent in the ALS mice at about 15 weeks of age, with a significant decrease in stance width and an increase in the placement angle of their paws during walking. The novel observation of supernormal walking, however, in the presymptomatic mice may provide new avenues for disease prevention and treatment. Dr. Thomas G. Hampton, who presented the findings at "Neuroscience 2005", surmised that heightened electrical activity of the muscles may contribute to these phenomena, or that chronically elevated electrical excitability in motor neurons may contribute to the fatal neurodegeneration of ALS. "These observations suggest that prophylactic treatment with drugs that attenuate muscle sympathetic nerve activity could prevent or delay the onset and course of the disease," said Dr. Hampton. Studies are underway to test this hypothesis.