The proteome of fetal fluids in mares with experimentally-induced placentitis.

This study examines the proteins found in fetal fluids of mares with induced placentitis. Researchers found notable proteins that could be future markers for diagnosing the disease.

Research Overview

In this study, researchers aimed to better understand placentitis, a leading cause of late-term abortion in mares, by identifying and analyzing proteins (the proteome) from fetal fluids (amniotic and allantoic) in healthy mares and those with induced placentitis. This was done through LTQ-Orbitrap mass-spectrometry of the collected fluids.

Methodology

• The mares were divided into control mares (n = 5) and experimentally-induced placentitis mares (n = 5).
• Placentitis was artificially introduced in the latter group via trans-cervical inoculation of Streptococcus equi ssp. zooepidemicus.

Findings

• Through this process, 130 proteins were identified either in amniotic fluid, allantoic fluid, or both. It was noted that amniotic proteins were more prevalent and better conserved across samples.
• The researchers discovered that 18 proteins were up-regulated (increased in response to a stimulus) in amniotic fluid during placentitis, including haptoglobin, plasminogen isoform X2 and plasminogen-like isoform X1, which were exclusively found in samples from mares with placentitis.
• Five allantoic proteins were up-regulated, four of which were also found to be up-regulated in amniotic fluid. These included alpha-1-antiproteinase and transferrin family members.
• Additionally, 19 proteins were down-regulated (decreased in response to a stimulus) in amniotic fluid, while no significant decrease was noted in allantoic fluid.

Significance and Future Applications

• This study represents the first proteomic analysis of amniotic and allantoic fluid during placental infection in any domestic livestock species, marking a significant advancement in research of placentitis.
• A number of proteins with significantly altered expression were identified—primarily those related to immune function—providing deeper insights into the physiology of placentitis.
• These findings have the potential to facilitate the identification of biomarkers for future diagnostic work, with the intention of improving early diagnosis and treatment.