Benefit of vitamin E, riluzole, and gababapentin in a transgenic model of familial amyotrophic lateral sclerosis

TLDR

Familial amyotrophic lateral sclerosis is linked to dominant mutations in the SOD1 gene encoding Cu,Zn superoxide dismutase. The study aimed to investigate the etiology and therapy of FALS using a transgenic mouse model expressing mutant human Cu,Zn SOD. The authors used this transgenic model to induce oxidative stress in the brain and spinal cord. Mutant Cu,Zn SOD expression caused oxidative stress and vitamin E depletion; dietary vitamin E delayed disease onset and slowed progression but did not extend survival, whereas riluzole and gabapentin prolonged survival without delaying onset, indicating distinct therapeutic effects and supporting a role for oxidative damage in weak excitotoxicity.

Abstract

Abstract Familial amyotrophic lateral sclerosis (FALS) has been linked in some families to dominant mutations of the SOD1 gene encoding Cu,Zn superoxide dismutase (Cu,Zn SOD). We have used a transgenic model of FALS based on expression of mutant human Cu,Zn SOD to explore the etiology and therapy of the genetic disease. Expression of mutant, but not wild‐type, human Cu,Zn SOD in mice places the brain and spinal cord under oxidative stress. This causes depletion of vitamin E, rather than the typical age‐dependent increase in vitamin E content as occurs in nontransgenic mice and in mice expressing wild‐type human Cu,Zn SOD. Dietary supplementation with vitamin E delays onset of clinical disease and slows progression in the transgenic model but does not prolong survival. In contrast, two putative inhibitors of the glutamatergic system, riluzole and gabapentin, prolong survival. However, riluzole did not delay disease onset. Thus, there was clear separation of effects on onset, progression, and survival by the three therapeutics tested. This suggests the hypothesis that oxidative damage produced by the expression of mutant Cu,Zn SOD causes slow or weak excitotoxicity that can be inhibited in part by altering glutamate release or biosynthesis presynaptically.