Relationships among inflammatory cytokines, obesity, and insulin sensitivity in the horse1,2

Autor: B. J. Shelton, David W. Horohov, Amanda A. Adams, R. F. Cook, B. P. Fitzgerald, Mandi M. Vick, Barbara A. Murphy, D. R. Sessions
Rok vydání: 2007
Předmět:
Zdroj: Journal of Animal Science. 85:1144-1155
ISSN: 1525-3163
0021-8812
DOI: 10.2527/jas.2006-673
Popis: Recent studies associate obesity and in- sulin resistance in horses with development of abnor- mal reproductive function and debilitating laminitis. The factors contributing to insulin resistance in obese horses are unknown. However, human studies provide evidence that elevated inflammatory cytokines such as tumor necrosis factor α (TNFα), IL1, and IL6 play direct roles in development of obesity-associated insulin resis- tance. Thus, inflammation may be a key link between obesity and insulin resistance in horses. The aim of the current investigation was to examine possible relation- ships between obesity, inflammatory cytokines, and in- sulin sensitivity (IS) in the horse. Age was recorded and BCS and percent body fat (% FAT) were determined as measures of obesity in 60 mares. In addition, blood mRNA expression of IL1, IL6, and TNFα and circulat- ing concentrations of TNFα protein (TNFp) were deter- mined in each mare. Finally, fasted concentrations of insulin were determined, and IS was determined using the hyperinsulinemic, euglycemic clamp. Significant correlations between several variables provided evi- dence for the design of 4 population regression models to estimate relationships between measures of obesity, inflammatory factors, and IS in the sample population. The results of these analyses revealed that IS decreased as BCS and % FAT increased (P < 0.001) in the sample population. Additionally, increased IL1 (P < 0.05) and TNFp (P < 0.01) were associated with decreased IS. However, increased TNFα (P < 0.001) was associated with decreased IS only in mares 20 yr of age and older. Increased BCS and % FAT were associated with in- creased expression of TNFα (P = 0.053) and IL1 (P < 0.05), and increased TNFp (P < 0.05). Surprisingly, increased BCS and % FAT were associated with de- creased IL6 expression (P = 0.05) in mares
Databáze: OpenAIRE