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Changes in Adipose m RNA Expression between Previously Laminitic Ponies and Nonlaminitic Ponies in Summer and Winter
Author(s) -
Timpson A.J.,
Elliott J.,
Harris P.A.,
Cheng Z.,
Rainbow L.,
Mestre A.M.,
MenziesGow N.J.
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12323_15
Subject(s) - adipose tissue , laminitis , biology , inflammation , gene expression , gene , pathogenesis , medicine , endocrinology , horse , genetics , immunology , paleontology
Reasons for performing study Some ponies are predisposed to recurrent pasture‐associated laminitis, but the mechanisms underlying this remain unclear. Adipose tissue is a highly metabolically active tissue that secretes mediators which affect vascular function, insulin signalling and inflammation, all of which are potentially implicated in the pathogenesis of laminitis. Objectives To determine whether the gene expression of adipose tissue from previously laminitic ponies ( LP ) differs from nonlaminitic ponies ( NL ). Study design Subcutaneous adipose tissue was collected by biopsy from the neck region of healthy LP and NL (n = 6 each group) in the summer and winter. Methods Gene expression was determined using a 44 K equine expression microarray. Data were analysed using GeneSpring and Ingenuity Pathway Analysis. Genes with >2‐fold difference, P<0.01 were considered significant using a t test to analyse group and/or season. Results The most significant differences in global gene expression in adipose tissue were observed between summer and winter in both groups, with 244 ( NL ) and 174 ( LP ) genes differentially expressed. There was a significant difference between LP and NL groups in the summer (141 genes differentially expressed), whereas the 2 groups were more similar in the winter (40 genes differentially expressed). Eight of the top 10 upregulated genes and 3 of the top 5 canonical pathways that differed between LP and NL in the summer were associated with inflammation and/or immunity. Conclusions Laminitic ponies appear to have a different adipose tissue gene expression profile to NL , particularly in the summer. Inflammatory genes and pathways were significantly upregulated in the LP group suggesting higher levels of inflammation or priming of inflammatory pathways which may contribute to a predisposition to laminitis. Ethical animal research: The study was completed under Home Office Project Licence approved by the RVC Ethics and Welfare Committee. Sources of funding: This study was funded by Waltham®. A. Timpson is funded by the Mellon Equine Endowment Fund. Competing interests: Dr P . H arris is employed by W altham. The other authors have declared no competing interests.