Equine dysautonomia (grass sickness) is associated with altered plasma amino acid levels and depletion of plasma sulphur amino acids

McGorum, Bruce; Kirk, Julie

doi:10.2746/042516401776254763

Cited by 31 publications

(31 citation statements)

References 48 publications

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“…The low concentrations of methionine noted in FD and in-contact cats is consistent the depletion of methionine and cyst(e)ine reported in EGS and healthy in-contact horses [9]. In the present study it was unfortunately not possible to meaningful assess the cats’ cyst(e)ine status because the low plasma/serum cyst(e)ine concentrations noted in all cats were likely artefactual, due to cysteine interaction with sulphydryl groups on plasma proteins and subsequent loss when the protein was precipitated during sample preparation.…”

Section: Discussionsupporting

confidence: 81%

“…The increase in essential amino acids in FD may reflect increased tissue protein catabolism in response to reduced food intake. In contrast, horses with EGS had reduced plasma concentrations of many essential amino acids, consistent with severe protein malnutrition, and increased concentrations of some non-essential amino acids [9]. …”

Section: Discussionmentioning

confidence: 99%

“…Plasma/serum amino acid profiles were determined as previously described [9]. Tryptophan was not detectable by this method due to losses during sample preparation and analysis.…”

Section: Methodsmentioning

confidence: 99%

“…There has been no investigation of the potential role of genetic mutations, such as those which cause familial human dysautonomia [8]. Horses with acute EGS have reductions in plasma concentrations of the sulphur amino acids (SAA) cyst(e)ine and methionine, and perturbations in plasma amino acid profile consistent with severe protein malnutrition [9]. We hypothesise that SAA depletion in EGS may reflect xenobiotic exposure, since SAA are strong nucleophiles that trap, reduce, detoxify and facilitate the excretion of electrophilic compounds and free radicals derived from dietary toxins such as mycotoxins, plant lectins, sesquiterpene lactones and toxic amino acids [10–13].…”

Section: Introductionmentioning

confidence: 99%

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Alterations in amino acid status in cats with feline dysautonomia

McGorum

Symonds

Knottenbelt³

et al. 2017

PLoS ONE

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Feline dysautonomia (FD) is a multiple system neuropathy of unknown aetiology. An apparently identical disease occurs in horses (equine grass sickness, EGS), dogs, rabbits, hares, sheep, alpacas and llamas. Horses with acute EGS have a marked reduction in plasma concentrations of the sulphur amino acids (SAA) cyst(e)ine and methionine, which may reflect exposure to a neurotoxic xenobiotic. The aim of this study was to determine whether FD cats have alterations in amino acid profiles similar to those of EGS horses. Amino acids were quantified in plasma/serum from 14 FD cats, 5 healthy in-contact cats which shared housing and diet with the FD cats, and 6 healthy control cats which were housed separately from FD cats and which received a different diet. The adequacy of amino acids in the cats’ diet was assessed by determining the amino acid content of tinned and dry pelleted foods collected immediately after occurrences of FD. Compared with controls, FD cats had increased concentrations of many essential amino acids, with the exception of methionine which was significantly reduced, and reductions in most non-essential amino acids. In-contact cats also had inadequate methionine status. Artefactual loss of cysteine during analysis precluded assessment of the cyst(e)ine status. Food analysis indicated that the low methionine status was unlikely to be attributable to dietary inadequacy of methionine or cystine. Multi-mycotoxin screening identified low concentrations of several mycotoxins in dry food from all 3 premises. While this indicates fungal contamination of the food, none of these mycotoxins appears to induce the specific clinico-pathologic features which characterise FD and equivalent multiple system neuropathies in other species. Instead, we hypothesise that ingestion of another, as yet unidentified, dietary neurotoxic mycotoxin or xenobiotic, may cause both the characteristic disease pathology and the plasma SAA depletion.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 99%

“…Plasma/serum amino acid profiles were determined as previously described [9]. Tryptophan was not detectable by this method due to losses during sample preparation and analysis.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Alterations in amino acid status in cats with feline dysautonomia

McGorum

Symonds

Knottenbelt³

et al. 2017

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…A few years ago, a study on plasma amino acid profiles of EGS horses found that these were similar to those occurring in subacute/chronic cyanide toxicity (McGorum and Kirk 2001). Furthermore, horses grazing EGS pastures had higher blood cyanide, and plasma and urinary thiocyanate concentrations, which is consistent with an increased exposure to cyanogens (McGorum and Anderson 2002).…”

mentioning

confidence: 92%