Biomarkers for placental disease in mares.

This research paper examines the various biomarkers associated with placental disease in mares, discussing new discoveries that may aid in early and more reliable diagnoses to prevent adverse outcomes such as abortions, stillbirths, and neonatal deaths in horses.

Background

• Placentitis, an inflammation of the placenta, is a significant reason for cases of abortion, stillbirth, and neonatal death in horses.
• Currently, diagnosis relies on the observation of clinical signs and ultrasonography, but lacks sensitivity to detect early and subtle cases.

Role of Blood Markers

• Recent studies have shown that blood markers can provide an objective way of diagnosing placentitis in mares.
• Changes in steroids produced by the fetoplacental unit, in particular, have been linked to the existence of placentitis.

Changes in Steroid Production

• Increased peripheral progestogens have been observed in mares with chronic placentitis.
• Conversely, mares with an acute infection have shown a reduction in peripheral concentrations of progestogens.
• Estradiol-17β concentrations significantly decrease in the plasma of mares suffering from placentitis.

Acute-Phase Proteins and Alpha-fetoprotein

• Serum amyloid A, an acute-phase protein, has been found increased in the plasma of mares with placentitis, primarily due to secretions from endometrial and chorioallantoic areas.
• Increased alpha-fetoprotein, produced in the fetoplacental unit, is also seen in affected mares, indicating its potential as a biomarker.

MicroRNA and Proteomic Signatures

• A variety of microRNA have been identified in plasma and tissues of mares with experimentally induced placentitis, offering potential diagnostic utility, but testing in spontaneous cases is still needed.
• Unique proteomic signatures have been discovered in the fetal fluids of these mares, suggesting they could be useful for diagnosis.

Lack of Transabdominal Fetal Fluid Sampling

• Despite promising findings, the lack of commonly used transabdominal fetal fluid sampling limits the widespread use of these fluid-based diagnostic techniques.

The paper aims to highlight and discuss these recent discoveries surrounding biomarkers for placentitis, hoping to inspire future development and use of these biomarkers for accurate and early diagnosis of the disease in mares.