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

This study aimed to understand whether changes in certain inflammatory markers – cytokines IL-2, IL-5, IL-6, IL-10, IFNγ, and TNF – under field conditions could predict equine pregnancy complications. The findings showed that these markers increased in cases of certain types of placental infections, possibly acting as potential biomarkers. However, these markers didn’t change in cases of non-infectious causes of abortion.

Study Design and Participants

• The study involved 702 Thoroughbred mares, whose blood was drawn every week from December 2013 until they gave birth.
• The mares’ fetal membranes were examined thoroughly and categorized into four groups: ascending placentitis, focal mucoid placentitis, idiopathic abortion, and control.

Findings and Analysis

• The collected weekly serum samples were tested using an immunoassay to measure the concentrations of IL-2, IL-5, IL-6, IL-10, IFNγ, and TNF.
• The concentrations of these cytokines increased prior to birth in cases of both ascending placentitis and focal mucoid placentitis. The increase was significant when compared to control cases.
• However, cytokine profiles leading up to idiopathic abortions (where causes are unknown) were no different than those in control cases.

Conclusion and Implications

• The study suggested that serum cytokines could serve as potential biomarkers for predicting placental infection in horses. Detecting an increase in these cytokines could alert veterinarians to potential complications, potentially help manage them more effectively, and minimize abortion rates.
• On the other hand, the unchanged cytokine profiles in mares that experienced idiopathic abortions indicate that these biomarkers might not be useful for predicting non-infectious causes of abortions.
• This research was conducted in field conditions, increasing its potential for real-world application. It also highlighted the need for further research into other potential biomarkers of non-infectious causes of equine pregnancy complications.
• This is the first study that reported an elevation in cytokines during an episode of focal mucoid placentitis, whose causative agents include Nocardioform bacteria.