Premature senecence biomarkers in pediatric epilepsy patients and their association with comorbid cognitive impairment

Senescence, a steady loss of proliferative capacity triggered by complex pathways, has been studied in neurodegenerative diseases but remains obscure in epilepsy. This study aims to investigate whether the chronic stress of frequent seizures in children induces cellular senescence and, if so, its potential association with comorbid cognitive impairment. Peripheral blood mononuclear cells (PBMC) from children under 12 years of age were analyzed for senescence-associated β-galactosidase (SA-BetaGal) activity, telomere length, expression alterations of cell cycle arrest genes p53, p16, p21, and retinoblastoma (RB)along with telomerase reverse transcriptase (TERT), insulin-like growth factors (IGF). Furthermore, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) plasma levels were assessed. We compared these senescence markers in drug-resistant epilepsy patients with malformations of cortical development (MCD) to those in drug-responsive epilepsy patients and healthy controls. (n = 10 each). Our study showed similar levels of SA-BetaGal activity in PBMCs across all groups. Additional analysis of lymphocyte subsets revealed that CD8+ T cells from the drug-resistant epilepsy with MCD group exhibited higher SA-BetaGal activity. Drug-resistant epilepsy group was associated with the longest telomeres, followed by the drug-responsive epilepsy patients, both higher than healthy children. Also, TERT expression was significantly higher in the drug-resistant epilepsy patients. p53 and RB expressions were similar to healthy controls in drug-resistant epilepsy group, whereas p21 and p16 expressions were higher. Children with drug-resistant epilepsy with MDC showed significantly higher levels of IL-6 and TNF-alpha than healthy controls or children with drug-responsive epilepsy. Our results showed that no stress-induced premature or replicative senescence was detected in drug-resistant epilepsy patients with MCD, based on telomere length, cell cycle gene expression profile and SA-BetaGal activity levels. However, elevated proinflammatory cytokines and high p21/p16 expressions in the drug-resistant group suggested that ongoing seizures cause cellular stress and an inflammatory microenvironment, which may increase the susceptibility to senescence over time in children with drug-resistant epilepsy.