Vitamin E deficiency and risk of equine motor neuron disease.

Hussni O Mohammed,Thomas J Divers,Alexander De Lahunta,Brian A Summers

doi:10.1186/1751-0147-49-17

Abstract

BackgroundEquine motor neuron disease (EMND) is a spontaneous neurologic disorder of adult horses which results from the degeneration of motor neurons in the spinal cord and brain stem. Clinical manifestations, pathological findings, and epidemiologic attributes resemble those of human motor neuron disease (MND). As in MND the etiology of the disease is not known. We evaluated the predisposition role of vitamin E deficiency on the risk of EMND.MethodsEleven horses at risk of EMND were identified and enrolled in a field trial at different times. The horses were maintained on a diet deficient in vitamin E and monitored periodically for levels of antioxidants – α-tocopherols, vitamins A, C, β-carotene, glutathione peroxidase (GSH-Px), and erythrocytic superoxide dismutase (SOD1). In addition to the self-control another parallel control group was included. Survival analysis was used to assess the probability of developing EMND past a specific period of time.ResultsThere was large variability in the levels of vitamins A and C, β-carotene, GSH-Px, and SOD1. Plasma vitamin E levels dropped significantly over time. Ten horses developed EMND within 44 months of enrollment. The median time to develop EMND was 38.5 months. None of the controls developed EMND.ConclusionThe study elucidated the role of vitamin E deficiency on the risk of EMND. Reproducing this disease in a natural animal model for the first time will enable us to carry out studies to test specific hypotheses regarding the mechanism by which the disease occurs.

Highlights

Equine motor neuron disease (EMND) is a spontaneous neurologic disorder of adult horses which results from the degeneration of motor neurons in the spinal cord and brain stem
We believe that EMND, just as amyotrophic lateral sclerosis (ALS), may have a multifactorial etiology and that oxidative stress is a major contributing/predisposing factor, i.e., sufficient cause, in motor neuron death but not necessarily the sole etiologic agent/ factor
While the dietary practices which appear to favor the development of hypovitaminosis E in horses are not new, EMND was not identified prior to 1990

Summary

Introduction

Equine motor neuron disease (EMND) is a spontaneous neurologic disorder of adult horses which results from the degeneration of motor neurons in the spinal cord and brain stem. Pathological findings, and epidemiologic attributes resemble those of human motor neuron disease (MND). Spontaneous motor neuron diseases are uncommon in domestic animals. Where they have been subject to study, these disorders invariably demonstrate a familial pattern, occurring in specific breeds of animals such as Brittany Spaniel dogs [1], Brown Swiss cattle [2] and Yorkshire pigs [3]. Acta Veterinaria Scandinavica 2007, 49:17 http://www.actavetscand.com/content/49/1/17 identification [4] of equine motor neuron disease (EMND), a sporadically occurring motor neuron disease affecting several horse breeds including standardbred, thoroughbred, Quarter horse and Arab breeds. While EMND has been observed most frequently in the Quarter Horse breed, we believe that this is due to the manner in which these horses are housed and fed rather than by a primary genetic determination

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