Increased α-tocopherol metabolism in horses with equine neuroaxonal dystrophy.
Abstract: Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder associated with a vitamin E deficiency within the first year of life. Vitamin E consists of 8 isoforms metabolized by the CYP4F2 enzyme. No antemortem diagnostic test currently exists for eNAD/EDM. Objective: Based on the association of α-tocopherol deficiency with the development of eNAD/EDM, we hypothesized that the rate of α-tocopherol, but not γ-tocopherol or tocotrienol metabolism, would be increased in eNAD/EDM-affected horses. Methods: Vitamin E metabolism: Proof of concept (POC) study; eNAD/EDM-affected (n = 5) and control (n = 6) horses. Validation study: eNAD/EDM-affected Quarter Horses (QHs; n = 6), cervical vertebral compressive myelopathy affected (n = 6) horses and control (n = 29) horses. CYP4F2 expression and copy number: eNAD/EDM-affected (n = 12) and age- and sex-matched control (n = 11-12) horses. Methods: The rates of α-tocopherol/tocotrienol and γ-tocopherol/tocotrienol metabolism were assessed in equine serum (POC and validation) and urine (POC only) using liquid chromatography tandem mass spectrometry (LC-MS/MS). Quantitative reverse-transcriptase PCR (qRT-PCR) and droplet digital (dd)-PCR were used to assay expression and genomic copy number of a CYP4F2 equine ortholog. Results: Metabolic rate of α-tocopherol was increased in eNAD/EDM horses (POC,P < .0001; validation, P = .03), with no difference in the metabolic rate of γ-tocopherol. Horses with eNAD/EDM had increased expression of the CYP4F2 equine orthologue (P = .02) but no differences in copy number. Conclusions: Increased α-tocopherol metabolism in eNAD/EDM-affected QHs provides novel insight into alterations in vitamin E processing in eNAD/EDM and highlights the need for high-dose supplementation to prevent the clinical phenotype in genetically susceptible horses.
© 2021 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.
Publication Date: 2021-07-31 PubMed ID: 34331715PubMed Central: PMC8478026DOI: 10.1111/jvim.16233Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research investigated how vitamin E metabolism is altered in horses affected by an inherited neurogenerative disorder known as equine neuroaxonal dystrophy/degenerative myeloencephalopathy (eNAD/EDM). It proposed that the metabolism rate of a specific form of vitamin E called α-tocopherol, but not other forms, would be increased in affected horses.
Objective and Hypothesis
- The researchers aimed to understand the metabolism of Vitamin E in horses suffering from eNAD/EDM, an inherited neurodegenerative disorder. As previous findings highlighted that Vitamin E deficiency contributes to the development of this disease, they hypothesized that the metabolism rate of α-tocopherol, a specific isoform of Vitamin E would be higher in affected horses.
Methods
- The research involved observation and analysis of both eNAD/EDM-affected and healthy horses in Proof of Concept and validation studies. Additionally, horses with cervical vertebral compressive myelopathy, another form of neurodegenerative disorder, were also studied for validation.
- The metabolism rates of α-tocopherol/tocotrienol and γ-tocopherol/tocotrienol were analyzed in the serum and urine of the horses involved in the study through liquid chromatography tandem mass spectrometry (LC-MS/MS).
- The researchers also assessed the expression and genomic copy number of CYP4F2 equine ortholog, an enzyme involved in Vitamin E metabolism, using quantitative reverse-transcriptase PCR (qRT-PCR) and droplet digital (dd)-PCR.
Results
- The findings confirmed the original hypothesis – the metabolic rate of α-tocopherol was significantly increased in eNAD/EDM horses. However, there was no change in the metabolic rate of γ-tocopherol.
- They also found increased expression of the CYP4F2 equine ortholog enzyme in the horses with eNAD/EDM, but the copy number of this enzyme remained unchanged.
Conclusion
- The findings offer new insights into how vitamin E processing is altered in horses suffering from eNAD/EDM. It suggests the need for administering high-dose supplements of Vitamin E in genetically susceptible horses as a way to prevent the development of the disorder’s clinical phenotype. This possibly opens up new opportunities for the management and treatment of eNAD/EDM in horses.
Cite This Article
APA
Hales EN, Habib H, Favro G, Katzman S, Sakai RR, Marquardt S, Bordbari MH, Ming-Whitfield B, Peterson J, Dahlgren AR, Rivas V, Ramirez CA, Peng S, Donnelly CG, Dizmang BS, Kallenberg A, Grahn R, Miller AD, Woolard K, Moeller B, Puschner B, Finno CJ.
(2021).
Increased α-tocopherol metabolism in horses with equine neuroaxonal dystrophy.
J Vet Intern Med, 35(5), 2473-2485.
https://doi.org/10.1111/jvim.16233 Publication
Researcher Affiliations
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Biomedical Sciences, Section of Anatomic Pathology, Cornell University College of Veterinary Medicine, Ithaca, New York, USA.
- Department of Pathology and Immunology, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
- Michigan State University College of Veterinary Medicine, East Lansing, Michigan, USA.
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.
MeSH Terms
- Animals
- Chromatography, Liquid / veterinary
- Horse Diseases
- Horses
- Neuroaxonal Dystrophies / genetics
- Neuroaxonal Dystrophies / veterinary
- Tandem Mass Spectrometry / veterinary
- Vitamin E
- alpha-Tocopherol
Grant Funding
- L40 TR001136 / NCATS NIH HHS
- K01OD015134-01A1 / NIH HHS
- UC Davis Center for Equine Health
- L40 TR001136 / NIH HHS
- 20143842021796 / National Institute of Food and Agriculture
- K01 OD015134 / NIH HHS
Conflict of Interest Statement
Authors declare no conflict of interest.
References
This article includes 38 references
- Mayhew IG, Brown CM, Stowe HD. Equine degenerative myeloencephalopathy: a vitamin E deficiency that may be familial.. J Vet Intern Med 1987;1:45‐50.
- Aleman M, Finno CJ, Higgins RJ. Evaluation of epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses.. J Am Vet Med Assoc 2011;239:823‐833.
- Finno CJ, Estell KE, Katzman S. Blood and cerebrospinal fluid alpha‐tocopherol and selenium concentrations in neonatal foals with neuroaxonal dystrophy.. J Vet Intern Med 2015;29:1667‐1675.
- Burns EN, Finno CJ. Equine degenerative myeloencephalopathy: prevalence, impact, and management.. Vet Med (Auckl) 2018;9:63‐67.
- Finno CJ, Bordbari MH, Valberg SJ. Transcriptome profiling of equine vitamin E deficient neuroaxonal dystrophy identifies upregulation of liver X receptor target genes.. Free Radic Biol Med 2016;101:261‐271.
- Reed SM, Furr M, Howe DK. Equine protozoal myeloencephalitis: an updated consensus statement with a focus on parasite biology, diagnosis, treatment, and prevention.. J Vet Intern Med 2016;30:491‐502.
- Janes JG, Garrett KS, McQuerry KJ. Comparison of magnetic resonance imaging with standing cervical radiographs for evaluation of vertebral canal stenosis in equine cervical stenotic myelopathy.. Equine Vet J 2014;46:681‐686.
- Edwards L, Donnelly CG, Reed S. Serum and cerebrospinal fluid phosphorylated neurofilament heavy protein concentrations in equine neurodegenerative diseases equine.. Vet J 2021. Online ahead of print.
- Finno CJ, Valberg SJ. A comparative review of vitamin E and associated equine disorders.. J Vet Intern Med 2012;26:1251‐1266.
- Sontag TJ, Parker RS. Cytochrome P450 omega‐hydroxylase pathway of tocopherol catabolism. Novel mechanism of regulation of vitamin E status.. J Biol Chem 2002;277:25290‐25296.
- Schmolz L, Birringer M, Lorkowski S. Complexity of vitamin E metabolism.. World J Biol Chem 2016;7:14‐43.
- Swanson JE, Ben RN, Burton GW. Urinary excretion of 2,7,8‐trimethyl‐2‐(beta‐carboxyethyl)‐6‐hydroxychroman is a major route of elimination of gamma‐tocopherol in humans.. J Lipid Res 1999;40:665‐671.
- Galli F, Polidori MC, Stahl W. Vitamin E biotransformation in humans.. Vitam Horm 2007;76:263‐280.
- Habib H, Finno CJ, Gennity I. Simultaneous quantification of vitamin E and vitamin E metabolites in equine plasma and serum using LC‐MS/MS.. J Vet Diagn Invest 2021;33(3):506‐515.
- Favro G, Habib H, Gennity I. Determination of vitamin E and its metabolites in equine urine using liquid chromatography‐mass spectrometry.. Drug Test Anal 2021;13(6):1158‐1168.
- Yokota T, Uchihara T, Kumagai J. Postmortem study of ataxia with retinitis pigmentosa by mutation of the alpha‐tocopherol transfer protein gene.. J Neurol Neurosurg Psychiatry 2000;68:521‐525.
- Gotoda T, Arita M, Arai H. Adult‐onset spinocerebellar dysfunction caused by a mutation in the gene for the alpha‐tocopherol‐transfer protein.. N Engl J Med 1995;333:1313‐1318.
- Schultz M, Leist M, Elsner A. Alpha‐carboxyethyl‐6‐hydroxychroman as urinary metabolite of vitamin E.. Method Enzymol 1997;282:297‐310.
- Schuelke M, Elsner A, Finckh B. Urinary alpha‐tocopherol metabolites in alpha‐tocopherol transfer protein‐deficient patients.. J Lipid Res 2000;41:1543‐1551.
- Finno CJ, Famula T, Aleman M. Pedigree analysis and exclusion of alpha‐tocopherol transfer protein (TTPA) as a candidate gene for neuroaxonal dystrophy in the American Quarter Horse.. J Vet Intern Med 2013;27:177‐185.
- Blythe LL, Craig AM, Lassen ED. Serially determined plasma alpha‐tocopherol concentrations and results of the oral vitamin E absorption test in clinically normal horses and in horses with degenerative myeloencephalopathy.. Am J Vet Res 1991;52:908‐911.
- Finno CJ, Estell KE, Winfield L. Lipid peroxidation biomarkers for evaluating oxidative stress in equine neuroaxonal dystrophy.. J Vet Intern Med 2018;32:1740‐1747.
- NRC. Nutrient Requirements of Horses.. 6th ed. Washington, DC: NRC; 2007.
- Lunn DP, Mayhew IG. The neurologic evaluation of horses.. Equine Vet Educ 1989;1:94‐101.
- Nout YS, Reed SM. Cervical vertebral stenotic myelopathy.. Equine Vet Educ 2003;15:212‐223.
- Sharma G, Muller DP, O'Riordan SM. Urinary conjugated alpha‐tocopheronolactone—a biomarker of oxidative stress in children with type 1 diabetes.. Free Radic Biol Med 2013;55:54‐62.
- Liu SK, Dolensek EP, Adams CR. Myelopathy and vitamin E deficiency in six Mongolian wild horses.. J Am Vet Med Assoc 1983;183:1266‐1268.
- Dill SG, Correa MT, Erb HN. Factors associated with the development of equine degenerative myeloencephalopathy.. Am J Vet Res 1990;51:1300‐1305.
- Morinobu T, Yoshikawa S, Hamamura K. Measurement of vitamin E metabolites by high‐performance liquid chromatography during high‐dose administration of alpha‐tocopherol.. Eur J Clin Nutr 2003;57:410‐414.
- Nierenberg DW, Lester DC. Determination of vitamins A and E in serum and plasma using a simplified clarification method and high‐performance liquid chromatography.. J Chromatogr 1985;345:275‐284.
- Catignani GL, Bieri JG. Simultaneous determination of retinol and alpha‐tocopherol in serum or plasma by liquid chromatography.. Clin Chem 1983;29:708‐712.
- Dinis‐Oliveira RJ. Metabolism and metabolomics of ketamine: a toxicological approach.. Forensic Sci Res 2017;2:2‐10.
- Lavoie DS, Pailleux F, Vachon P. Characterization of xylazine metabolism in rat liver microsomes using liquid chromatography‐hybrid triple quadrupole‐linear ion trap‐mass spectrometry.. Biomed Chromatogr 2013;27:882‐888.
- Gorski JC, Hall SD, Jones DR. Regioselective biotransformation of midazolam by members of the human cytochrome P450 3A (CYP3A) subfamily.. Biochem Pharmacol 1994;47:1643‐1653.
- Pusterla N, Puschner B, Steidl S. Alpha‐tocopherol concentrations in equine serum and cerebrospinal fluid after vitamin E supplementation.. Vet Rec 2010;166:366‐368.
- Higgins JK, Puschner B, Kass PH. Assessment of vitamin E concentrations in serum and cerebrospinal fluid of horses following oral administration of vitamin E.. Am J Vet Res 2008;69:785‐790.
- Brown JC, Valberg SJ, Hogg M. Effects of feeding two RRR‐alpha‐tocopherol formulations on serum, cerebrospinal fluid and muscle alpha‐tocopherol concentrations in horses with subclinical vitamin E deficiency.. Equine Vet J 2017;49:753‐758.
- Handelman GJ, Machlin LJ, Fitch K. Oral alpha‐tocopherol supplements decrease plasma gamma‐tocopherol levels in humans.. J Nutr 1985;115:807‐813.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
