Selenium and Glutathione Peroxidase Levels in Persons with Epilepsy and Healthy Controls in Two Tertiary Hospitals in North West Nigeria: A Comparative Study

Abstract

Introduction:  Oxidative stress and increased reactive oxygen species have been implicated in recurrent seizures, but selenium containing glutathione peroxidase are reported to protect against oxidative damage and promote neuronal cell survival.  Aim: We compared levels of selenium and glutathione peroxidase in persons with epilepsy (PWE) and healthy controls. Study Design: A hospital-based cross-sectional case-control study. Place and Duration of Study: This study was carried out from June to December 2014 at neurology outpatient clinics of Ahmadu Bello University Teaching Hospital (ABUTH) Zaria and Neuropsychiatry Hospital Barnawa, Kaduna. Methodology: We collected blood samples from three categories each of 35 subjects (AED-naïve; AEDs-experienced, and healthy controls) after ethical approval and informed consent, for determination of serum selenium and glutathione peroxidase using Atomic Absorption Spectroscopy and ELISA methods respectively. Statistical analysis was done using ANOVA followed by Bonferroni post hoc test, and significant level was defined as P ≤ 0.05. Results: The mean age ± SEM of the controls, patients on AEDs and new patients were 33.31 ± 1.80, 33.91 ± 2.35 and 31.25 ± 2.48 years respectively with no significant difference (P = 0.091). In each study group majority of them, 22 (62.9%) were male and 13 (37.1%) were female. Selenium level was significantly higher in AED-experienced PWE than AED-naïve PWE (P = 0.001) and healthy controls (P = 0.000), but was not significantly different between AED-naïve PWE and healthy controls (P = 1.000). Glutathione peroxidase level was significantly lower in AED-experienced PWE than AED-naïve PWE (P = 0.000) and healthy controls (P = 0.000), and also significantly lower in AED-naïve PWE than healthy controls (P = 0.01).  Selenium correlated negatively with GPX (r = - 0.289, P = 0.003). There was no significant relationship between selenium, GPX with clinical variables like age at onset, duration of illness, seizure frequency and seizure type (P > 0.05).  Conclusion: Selenium level in the follow up group (ASM – experienced) was significantly higher than the new patients (ASM- naïve) and healthy controls. GPX level in ASM – experienced PWE was significantly lower than ASM - naive and healthy controls. The finding suggests the therapeutic potential of selenium supplementation in new PWE.