Abstract

Clinical pathophysiological insights

ALS and excitotoxicity

ALS and oxidative stress

Excitotoxicity and oxidative stress

References

Discussion
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Amytrophic Lateral Sclerosis (ALS) is the principal human motor neuron disease. The neuropathology is marked by the degeneration of lower motor neurons in spinal cord and brainstem and by the death of large neurons of the motor cortex. The cause of sporadic ALS is unknown nor it is known why these cells are selectively impaired in ALS. Recent findings have highlighted two major hypothesis at the origin of the disease ; excitotoxicity and oxidative stress. Excitotoxicity linked to glutamate toxic properties is responsible for post-synaptic neuronal degeneration and was proposed as a pathogenic factor in various acute or chronic neurological disorders. For example, Lathyrism linked to the excitotoxin BOAA is marked by a rather pure impairment of motor tracts in humans. The re-uptake of glutamate was found decreased in the motor cortex and spinal cord of ALS patients. This could be associated with the reduced expression of the glutamate transporter EAAT-2 detected in patients. ALS CSF contains excitotoxic factors leading to neuronal death in cultures. In addition mutations of the SOD1 gene were discovered in subgroups of familial ALS patients. Oxidative stress or accumulation of mutated SOD1 could be the cause of motoneuron death in the mice transgenic model of ALS. The association of oxidative stress and excitotoxicity could be both at the origin of motoneuron death in ALS.

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Presentation Number SAhugon j.0510
Keywords: ALS, Excitotocity, Oxidative Stress