Glutamate and Nitric Oxide as biomarkers for disease activity in patients with multiple sclerosis

•Serum glutamate and nitric oxide are significantly higher in MS patients during relapse.•Serum glutamate and nitric oxide levels can predict occurrence of a relapse.•There is positive correlation between glutamate and nitric oxide in MS patients. Despite multiple diagnostic tests, multiple sclerosis (MS) remains a clinical diagnosis with supportive paraclinical evidence. To measure glutamate and nitric oxide serum levels in MS patients during and in between relapses to assess their potential role as biomarkers of disease activity and relapses. This cross sectional study was carried out on 70 MS patients and 40 age and sex matched apparently healthy controls. MS patients were divided into 2 groups; group 1 that included thirty MS patients without history of relapse within the last 3 months prior to recruitment and group 2 that included forty MS patients with history of relapse within the last 30 day prior to recruitment. Serum glutamate was significantly higher in group 2 (24.67 ± 9.58 μg/ml) compared to group 1(12.5 ± 4.9 μg/ml) (P value < 0.0001) and apparently healthy controls (3.5 ± 1.3 μg/ml) (P value < 0.0001). Serum nitric oxide was significantly higher in group 2 (84.87 ± 29.6 nmol/μl) than group 1 (41.99 ± 24.2 nmol/μl) (P value < 0.0001) and apparently healthy controls (12.03 ± 3.59 nmol/μl) (P value < 0.0001). Cutoff values of 17.5 μg/ml for glutamate and 75.2 nmol/μl for nitric oxide were found to predict occurrence of a relapse (sensitivity = 70% and 72.5% and specificity= 90% and 93.3% respectively). Serum glutamate and nitric oxide can be potential easily-accessible biomarkers of disease activity and relapses in MS patients.