Abstract: Background– Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is increasingly recognized as a cause of neurologic disease in adult horses. Diagnosis requires postmortem examination, with no accurate antemortem diagnostic test available. 8-hydroxy-2’-deoxyguanosine(8-OHdG), a biomarker of oxidative damage utilized in human neurodegenerative disease, has potential to correlate with postmortem diagnosis of eNAD/EDM.
Hypothesis/Objectives– We hypothesized that 8-OHdG will be increased in CSF and serum from eNAD/EDM horses compared to horses with other neurologic diseases (CVSM, EPM) and a control group of neurologically normal horses. 8-OHdG will be increased in CSF compared to serum of eNAD/EDM horses.
Animals– Case-control study using biobanked samples from 50 horses with postmortem diagnoses (20 with eNAD/EDM, 10 in each group- EPM, CVSM, and control).
Methods– A commercial competitive ELISA kit (Highly Sensitive 8-OHdG Check ELISA) previously used in a study of horses with asthma was utilized. Concentration of 8-OHdG was quantitated in both CSF and serum and compared between groups.
Results– The mean concentration of 8-OHdG amongst all groups was 179.3 pg/mL (41.5-635.4) in CSF and 150.1 pg/mL (36.8-857.5) in serum. Poisson regression showed no significant difference once confounding variables (breed, age, sample age, vitamin E concentration) were considered.
Conclusions– 8-OHdG is detectable in equine CSF and serum, although does not aid in antemortem diagnosis of eNAD/EDM. The findings support the concept that at the time of diagnosis horses with eNAD/EDM do not have ongoing oxidative stress, and that further studies are needed to improve our ability to obtain an antemortem diagnosis.
