Background: Oxidative stress from vitamin E deficiency is a risk factor for equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM). Prior research found no differences in CSF 8-hydroxy-2'-deoxyguanosine concentration ([8-OHdG]), a biomarker of oxidative stress, between eNAD/EDM adults and controls, suggesting earlier or intermittent oxidative stress might trigger disease.
Hypothesis/
Objectives: 1) To investigate temporal CSF [8-OHdG] changes in vitamin E-deprived foals: one group with increased CSF phosphorylated neurofilament heavy concentrations ([pNfH]) that developed eNAD/EDM, and one that did not. 2) To assess correlations among 8-OHdG, pNfH, and serum vitamin E.
Methods: Case-control study quantifying serum and CSF [8-OHdG] via ELISA, with serum vitamin E and CSF [pNfH] available retrospectively. Foal data were analyzed using mixed-effects models, and adult data using linear regression and Spearman’s correlation.
Results: Foal CSF [8-OHdG] showed a temporal pattern: lower in eNAD foals than controls at day 60 (20.80 pg/mL vs. 47.90 pg/mL, P = 0.01) but higher at day 120 (78.68 pg/mL vs. 15.64 pg/mL, P < 0.001); no difference was detected at day 180. In foals, CSF [8-OHdG] inversely correlated with serum vitamin E (P < 0.005) and positively with CSF [pNfH] (P = 0.02). In adults, no differences or correlations were detected.
Conclusions and Clinical Importance: CSF [8-OHdG] reflects time-dependent oxidative stress in eNAD/EDM foals. Lack of adult differences suggests oxidative activity wanes by maturity despite persistent axonal injury detected by increased pNfH.
