Blood oxidative stress in amyotrophic lateral sclerosis

It has been suggested that amyotrophic lateral sclerosis (ALS), a neurodege nerative disorder resulting in motor neuron death, is associated with oxida tive damage induced by free radicals. Our study aimed to get an assessment of the blood oxidative stress status in a population of 167 ALS patients (a ged 59+/-13 years), treated or not with riluzole, compared with 62 age-matc hed healthy control subjects (aged 60+/-11 years) simultaneously included i n the study. We determined the level of plasma lipid peroxidation (thiobarb ituric acid-reactive substances, TBARS); the status of the major lipophilic plasma antioxidant defenses (vitamin E, vitamin A and beta-carotene); the activities of erythrocyte Cu,Zn-superoxide dismutase (Cu,Zn-SOD) and of pla sma and erythrocyte glutathione peroxidase (GSH-Px). Plasma selenium was al so determined as a trace element essential to the activity of the GSH-Px. I n comparison with controls, we observed in ALS patients (mean+/-S.D.) signi ficantly higher TEARS values (ALS=1.34+/-0.28 mu mol/l; controls=1.11+/-0.2 0 mu mol/l) and a significant enhancement of the erythrocyte SOD activity ( ALS=710+/-114 U/g Hb; controls=667+/-93 U/g Hb). No differences were observ ed for selenium level, GSH-Px activity, plasma vitamin E, beta-carotene and Vitamin A concentrations. These data confirm the presence of an oxidative stress in blood of ALS patients. The elevated plasma TEARS, without any def iciency in plasma lipophilic antioxidants such as vitamin E, vitamin A and beta-carotene, suggest an enhancement in the production of free radicals. N o correlation was found in our study between the level of any of the blood oxidative stress markers and the disease duration. Comparison between patie nts treated or not with riluzole did not display any modification of the pl asma TEARS concentration, but we observed a slight decrease of erythrocyte SOD activity in treated patients (treated=705+/-113 U/g Hb; not treated=725 +/-118 U/g Hb), suggesting a possible activity of riluzole on the oxygenate d free radical production. (C) 2000 Elsevier Science B.V. All rights reserv ed.