Decreased chloride levels of cerebrospinal fluid in patients with amyotrophic lateral sclerosis

Recent studies have suggested that the elevation of intracellular chloride contributes to excitotoxic cell death in motor neuron and can be related to the pathogenesis of amyotrophic lateral sclerosis (ALS). We investigated whether chloride levels in cerebrospinal fluid (CSF) and serum were lower in ALS patients than in control patients with other neurological diseases (OND). We also examined the relationship between chloride levels and clinical ALS phenotypes. We measured chloride levels (CSF and serum) in 27 ALS patients and 33 age- and gender-matched OND controls admitted to our hospital for diagnosis. The CSF chloride levels were lower in ALS patients (117 [range 102-130] mmol/L) than in OND controls (126 [range 114-134] mmol/L) (P<0.0001). However, no significant difference was found in their serum chloride levels (P>0.05). There was no significant difference in CSF chloride levels among the sub-groups of ALS patients classified according to their age, gender, duration of illness, clinical state and type of onset (P>0.05). CSF chloride levels already significantly decreased in ALS patients at the time of diagnosis. We conclude that the elevation of intracellular chloride would cause the reduction of chloride in CSF and be related to the pathogenesis of ALS. (c) 2009 Elsevier B.V. All rights reserved.