Measurement of Plasma Resistin Concentrations in Horses with Metabolic and Inflammatory Disorders

Abstract

Obesity and its associated complications, such as metabolic syndrome, are an increasing problem in both humans and horses in the developed world. The expression patterns of resistin differ considerably between species. In rodents, resistin is expressed by adipocytes and is related to obesity and ID. In humans, resistin is predominantly produced by inflammatory cells, and resistin concentrations do not reflect the degree of obesity, although they may predict cardiovascular outcomes. The aim of this study was to investigate the usefulness of resistin and its relationship with ID and selected indicators of inflammation in horses. Seventy-two horses, included in one of the four following groups, were studied: healthy controls (C, n = 14), horses with inflammatory conditions (I, n = 21), horses with mild ID (ID1, n = 18), and horses with severe ID (ID2, n = 19). Plasma resistin concentrations were significantly different between groups and the higher values were recorded in the I and ID2 groups (C: 2.38 1.69 ng/mL; I: 6.85 8.38 ng/mL; ID1: 2.41 2.70 ng/mL; ID2: 4.49 3.08 ng/mL). Plasma resistin was not correlated with basal insulin concentrations. A significant (r = 0.336, p = 0.002) correlation was found between resistin and serum amyloid A. Our results show that, as is the case in humans, plasma resistin concentrations in horses are predominantly related to inflammatory conditions and not to ID. Horses with severe ID showed an elevation in resistin that may be secondary to the inflammatory status associated with metabolic syndrome.

La obesidad y sus complicaciones asociadas, como el síndrome metabólico, son un problema creciente tanto en humanos como en caballos en el mundo desarrollado. Los patrones de expresión de la resistina difieren considerablemente entre especies. En los roedores, la resistina se expresa en los adipocitos y está relacionada con la obesidad y la ID. En humanos, la resistina es producida predominantemente por células inflamatorias, y las concentraciones de resistina no reflejan el grado de obesidad, aunque pueden predecir resultados cardiovasculares. El objetivo de este estudio era investigar la utilidad de la resistina y su relación con la ID y determinados indicadores de inflamación en caballos. Se estudiaron 72 caballos, incluidos en uno de los cuatro grupos siguientes: controles sanos (C, n = 14), caballos con afecciones inflamatorias (I, n = 21), caballos con ID leve (ID1, n = 18) y caballos con ID grave (ID2, n = 19). Las concentraciones plasmáticas de resistina fueron significativamente diferentes entre los grupos y los valores más altos se registraron en los grupos I e ID2 (C: 2,38 1,69 ng/mL; I: 6,85 8,38 ng/mL; ID1: 2,41 2,70 ng/mL; ID2: 4,49 3,08 ng/mL). La resistina plasmática no se correlacionó con las concentraciones basales de insulina. Se halló una correlación significativa (r = 0,336, p = 0,002) entre la resistina y el amiloide A sérico. Nuestros resultados muestran que, al igual que ocurre en los seres humanos, las concentraciones de resistina plasmática en los caballos están relacionadas predominantemente con afecciones inflamatorias y no con la ID