Increased α-tocopherol metabolism in horses with equine neuroaxonal dystrophy.
Authors: Hales Erin N, Habib Hadi, Favro Gianna, Katzman Scott, Sakai R Russell, Marquardt Sabin, Bordbari Matthew H, Ming-Whitfield Brittni, Peterson Janel, Dahlgren Anna R, Rivas Victor, Ramirez Carolina Alanis, Peng Sichong, Donnelly Callum G, Dizmang Bobbi-Sue, Kallenberg Angelica, Grahn Robert, Miller Andrew D, Woolard Kevin, Moeller Benjamin, Puschner Birgit, Finno Carrie J
Journal: Journal of veterinary internal medicine
Summary
Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) remains a significant challenge in young horses, presenting as a neurodegenerative condition linked to vitamin E insufficiency during the critical first year of life, yet clinicians currently lack a reliable antemortem diagnostic tool. Researchers investigated whether alterations in α-tocopherol (the most biologically active vitamin E isoform) metabolism, specifically through the CYP4F2 enzyme pathway, might distinguish affected horses and potentially enable earlier diagnosis. Although specific numerical findings from the study require reference to the full paper, the work demonstrated measurable differences in how affected horses metabolise vitamin E compared to healthy controls, suggesting that enzyme activity or metabolite profiles could serve as biomarkers. These metabolic signatures offer meaningful potential for developing a practical antemortem diagnostic test—something that would allow veterinarians to identify affected foals before irreversible neurological damage occurs and inform breeding decisions in at-risk lines. For nutritionists and veterinarians working with young horses, particularly those from known susceptible bloodlines, these findings underscore the importance of maintaining adequate vitamin E status from birth whilst pointing towards a future diagnostic pathway that could substantially improve management and prevention strategies.
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Practical Takeaways
- •Monitor foals for signs of neuroaxonal dystrophy during the first year of life, as early detection may improve outcomes with vitamin E supplementation
- •Consider vitamin E supplementation protocols for at-risk foals or those with family history of eNAD/EDM, given the association with deficiency
- •Work with veterinarians and breed organizations to develop screening strategies, as increased α-tocopherol metabolism in affected animals may require higher supplementation levels than currently recommended
Key Findings
- •eNAD/EDM is an inherited neurodegenerative disorder associated with vitamin E deficiency manifesting within the first year of life
- •Vitamin E metabolism involves 8 isoforms that are processed by the CYP4F2 enzyme
- •Horses with eNAD/EDM demonstrate increased α-tocopherol metabolism compared to unaffected horses
- •No antemortem diagnostic test currently exists for eNAD/EDM, limiting early identification and intervention