Oxidative stress, metalloproteinase and LDH in children with intractable and non-intractable epilepsy as reflected in salivary analysis

• Mean salivary LDH and MMP9 concentration decrease in epilepsy patients.
• Mean salivary peroxidase, SOD activity and carbonyls increase in epilepsy patients.
• Salivary oxidative component levels are useful in detection/follow-up of epilepsy.

SummaryOxidative stress and metalloproteinase (MMPs) may have a pivotal role in the pathogenesis of epilepsy. This study examined the underlying mechanism of epilepsy in children and especially in its intractable form, with respect to the roles of MMP's and free radicals in general and in saliva in particular. We also explored the possible diagnostic role of a compositional salivary analysis in these children, as salivary collection is simple, non-invasive (and thus ‘children-friendly’) and requires almost no expertise. We analyzed saliva parameters of 33 epileptic children: 22 with non-intractable (E's) and 11 with intractable epilepsy (IE's), and compared them with 16 healthy controls. Mean salivary LDH concentration in controls was 213.1 ± 34.0 IU/L, dropping by 38% (p = 0.014) in E's and by 76% (p = 0.0003) in IE's. Mean salivary values of peroxidase activity, SOD activity and carbonyls level were 480 ± 14 mU/mL, 1.30 ± 0.15 U/mL and 0.34 ± 0.04 nmol/mg, respectively, in controls, increasing by 6% (p = 0.03), by 37% (p = 0.04) and by 59% (p = 0.003) in E's, and by 10% (p = 0.02), by 29% (p = 0.03) and by 56% (p = 0.004) in IE's. Mean salivary MMP 9 concentration was 0.062 ± 0.003 (OD) in controls, decreased by 12% (p = 0.048) in E's, and by 23%, (p = 0.009) in IE's. Our results enhance our understanding of epilepsy's biological underlying mechanism as reflected in the saliva of children with both intractable and non intractable disease.SignificanceThe currently reported salivary analysis and the demonstrated salivary alterations in children suffering from epilepsy represent a novel direction. We found various salivary alterations demonstrated in the general composition as well as the oxidative and metalloproteinase analyses and more so in the intractable epilepsy group than in the non intractable epilepsy group. Hence, salivary oxidative components and MMP levels were found useful in the detection and follow-up of children with epilepsy. As such, we recommend using this non-invasive salivary analysis for diagnosis and monitoring of epileptic activity in children.