title: Relationship of skeletal muscle inflammation with obesity and obesity-associated hyperinsulinemia in horses.
abstract: Local (skeletal muscle and adipose) and systemic inflammation are implicated in the development of obesity-associated insulin resistance in humans. In horses, obesity is neither strongly nor consistently associated with systemic inflammation. The role of skeletal muscle inflammation in the development of insulin dysregulation (insulin resistance or hyperinsulinemia) remains to be determined. We hypothesized that skeletal muscle inflammation is related to obesity-associated hyperinsulinemia in horses. Thirty-five light-breed horses with body condition scores (BCSs) of 3/9 to 9/9 were studied, including 7 obese, normoinsulinemic (BCS ≥ 7, resting serum insulin < 30 μIU/mL) and 6 obese, hyperinsulinemic (resting serum insulin ≥ 30 μIU/mL) horses. Inflammatory biomarkers were evaluated in skeletal muscle biopsies and plasma. Relationships between markers of inflammation and BCS were evaluated. To assess the role of inflammation in obesity-associated hyperinsulinemia, markers of inflammation were compared among lean or ideal, normoinsulinemic (L-NI); obese, normoinsulinemic (O-NI); and obese, hyperinsulinemic (O-HI) horses. Skeletal muscle and plasma tumor necrosis factor alpha (TNFα) concentrations were negatively correlated with BCS. When comparing inflammatory markers among groups, skeletal muscle TNFα was lower in the O-HI group than in the O-NI or L-NI groups. In horses, neither skeletal muscle nor systemic inflammation appears to be positively related to obesity or obesity-associated hyperinsulinemia.
authors.affiliation: Department of Physiological Sciences (Banse, McFarlane) and Department of Veterinary Clinical Sciences (Holbrook), Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA; Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA (Frank).
authors.forename: Heidi E
authors.initials: HE
authors.lastname: Banse
authors.affiliation: Department of Physiological Sciences (Banse, McFarlane) and Department of Veterinary Clinical Sciences (Holbrook), Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA; Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA (Frank).
authors.forename: Todd C
authors.initials: TC
authors.lastname: Holbrook
authors.affiliation: Department of Physiological Sciences (Banse, McFarlane) and Department of Veterinary Clinical Sciences (Holbrook), Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA; Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA (Frank).
authors.forename: Nicholas
authors.initials: N
authors.lastname: Frank
authors.affiliation: Department of Physiological Sciences (Banse, McFarlane) and Department of Veterinary Clinical Sciences (Holbrook), Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA; Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts 01536, USA (Frank).
authors.forename: Dianne
authors.initials: D
authors.lastname: McFarlane
mesh_terms: D000818:Animals; D015415:Biomarkers; D005260:Female; D005786:Gene Expression Regulation; D006734:Horse Diseases / Q000209:etiology*; D006736:Horses; D006946:Hyperinsulinism / Q000150:complications / Q000662:veterinary*; D007249:Inflammation / Q000150:complications / Q000662:veterinary*; D007328:Insulin / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology*; D009135:Muscular Diseases / Q000150:complications / Q000662:veterinary*; D009765:Obesity / Q000150:complications / Q000662:veterinary*
chemical_list: D015415:Biomarkers; D007328:Insulin