Alterations of Circulating Biomarkers During Late Term Pregnancy Complications in the Horse Part I: Cytokines.

Abstract

Equine abortions are attributed to both infectious and noninfectious causes. Clinical extrapolations are often made from the experimental model for ascending placentitis towards other causes&#xa0;of fetal compromise, including various markers of inflammation, including the cytokines IL-2, 5, IL-6, IL-10,&#xa0;IFN&#x3b3;, and TNF. It is unknown if these cytokine changes are noted under field conditions, or if they increase preceding other pregnancy related complications. To assess this,&#xa0;Thoroughbred mares (n&#xa0;=&#xa0;702) had weekly blood obtained beginning in December 2013 and continuing until parturition. Fetal membranes&#xa0;were submitted to the UKVDL for complete gross and pathologic assessment and classified as either ascending placentitis (n&#xa0;=&#xa0;6), focal mucoid placentitis (n&#xa0;=&#xa0;6), idiopathic abortion (n&#xa0;=&#xa0;6) or control (n&#xa0;=&#xa0;20). Weekly serum samples were analyzed via immunoassay for concentrations of IL-2, IL-5, IL-6, IL-10, IFN&#x3b3;, and TNF. For both focal mucoid placentitis and ascending placentitis, an increase (P < .05) in the concentrations of IL-2, IL-5, IL-6, IL-10,&#xa0;IFN&#x3b3;, and TNF was noted preceding parturition in comparison to controls. Cytokine profiles preceding idiopathic abortion did not differ from controls. In conclusion,&#xa0;serum cytokines may be considered potential biomarkers for the prediction of placental infection, while no changes in cytokine profiles were noted when noninfectious causes of abortion&#xa0;occurred. Additionally,&#xa0;this is the first study to report an increase in cytokines during the disease process of focal mucoid placentitis, the etiology of which includes Nocardioform placentitis.