Senescence markers in peripheral blood mononuclear cells in pediatric drug-resistant epilepsy.

SA-β-galactosidase activity in whole PBMCs was similar across drug-resistant epilepsy, drug-responsive epilepsy, and healthy control groups.

• n = 10 per group, all children under 12 years of age
• Drug-resistant epilepsy patients had malformations of cortical development (MCD)
• SA-β-gal is a canonical marker of cellular senescence
• Similar PBMC SA-β-gal levels across all groups indicated no established senescence at the whole PBMC level

CD8+ T cell subgroup analysis from the drug-resistant epilepsy group exhibited higher SA-β-galactosidase activity compared to other groups.

• SA-β-gal subgroup analysis was performed specifically on CD8+ T cells
• Higher SA-β-gal activity was found in CD8+ T cells from the drug-resistant epilepsy group
• This finding was distinct from the whole PBMC analysis which showed no group differences
• CD8+ T cells are a component of PBMCs relevant to immune surveillance and senescence

The drug-resistant epilepsy group was associated with the longest telomeres and high telomerase reverse transcriptase (TERT) expression.

• Telomere length was measured in PBMCs from all three groups (n = 10 each)
• Drug-resistant epilepsy patients had the longest telomeres compared to drug-responsive epilepsy and healthy controls
• TERT expression was high in the drug-resistant epilepsy group
• Longer telomeres with high TERT expression argued against replicative senescence in this group

p21 and p16 expression were higher in the drug-resistant epilepsy group, while p53 and RB expressions were similar to healthy controls.

• Cell cycle arrest genes measured included p53, p16, p21, and retinoblastoma (RB)
• p53 and RB expressions in the drug-resistant epilepsy group were comparable to healthy controls
• p21 and p16 expressions were elevated in the drug-resistant epilepsy group
• The dissociation between p21/p16 elevation and normal p53/RB levels suggested partial or atypical activation of senescence-related pathways

Children with drug-resistant epilepsy with MCD showed significantly higher levels of IL-6 and TNF-alpha than healthy controls or children with drug-responsive epilepsy.

• IL-6 and TNF-alpha were measured as markers of the senescence-associated secretory phenotype (SASP) and neuroinflammation
• Levels were significantly higher in the drug-resistant epilepsy (MCD) group compared to both healthy controls and drug-responsive epilepsy group
• n = 10 per group
• Elevated proinflammatory cytokines suggest ongoing inflammatory activity in drug-resistant pediatric epilepsy

No evidence of established stress-induced premature or replicative senescence was observed in drug-resistant epilepsy patients.

• Conclusion based on combined analysis of SA-β-gal (whole PBMCs), telomere length, TERT expression, and p53/RB expression
• The overall senescence marker profile did not fulfill criteria for classical premature or replicative senescence
• Despite this, elevated p21/p16 and proinflammatory cytokines were interpreted as evidence of cellular stress
• Authors suggest susceptibility to senescence may increase over time with ongoing seizures