Medicine and Health Sciences Commons^™

Estrogens Regulate Placental Angiogenesis In Horses, Shingo Haneda, Pouya Dini, Alejandro Esteller-Vico, Kirsten E. Scoggin, Edward L. Squires, Mats H. T. Troedsson, Peter Daels, Yasuo Nambo, Barry A. Ball

Maxwell H. Gluck Equine Research Center Faculty Publications

A sufficient vascular network within the feto-maternal interface is necessary for placental function. Several pregnancy abnormalities have been associated with abnormal vascular formations in the placenta. We hypothesized that growth and expansion of the placental vascular network in the equine (Equus caballus) placenta is regulated by estrogens (estrogen family hormones), a hormone with a high circulating concentration during equine gestation. Administration of letrozole, a potent and specific inhibitor of aromatase, during the first trimester (D30 to D118), decreased circulatory estrone sulfate concentrations, increased circulatory testosterone and androstenedione concentrations, and tended to reduce the weight of the fetus ( …

Kinetics Of The Chromosome 14 Microrna Cluster Ortholog And Its Potential Role During Placental Development In The Pregnant Mare, Pouya Dini, Peter Daels, Shavahn C. Loux, Alejandro Esteller-Vico, Mariano Carossino, Kirsten E. Scoggin, Barry A. Ball

Maxwell H. Gluck Equine Research Center Faculty Publications

Background: The human chromosome 14 microRNA cluster (C14MC) is a conserved microRNA (miRNA) cluster across eutherian mammals, reported to play an important role in placental development. However, the expression kinetics and function of this cluster in the mammalian placenta are poorly understood. Here, we evaluated the expression kinetics of the equine C24MC, ortholog to the human C14MC, in the chorioallantoic membrane during the course of gestation.

Results: We demonstrated that C24MC-associated miRNAs presented a higher expression level during early stages of pregnancy, followed by a decline later in gestation. Evaluation of one member of C24MC (miR-409-3p) by in situ hybridization …

Evaluation Of Circulating Mirnas During Late Pregnancy In The Mare, Shavahn C. Loux, Kirsten E. Scoggin, Jason E. Bruemmer, Igor F. Canisso, Mats H. T. Troedsson, Edward L. Squires, Barry A. Ball

Veterinary Science Faculty Publications

MicroRNAs (miRNAs) are small, non-coding RNAs which are produced throughout the body. Individual tissues tend to have a specific expression profile and excrete many of these miRNAs into circulation. These circulating miRNAs may be diagnostically valuable biomarkers for assessing the presence of disease while minimizing invasive testing. In women, numerous circulating miRNAs have been identified which change significantly during pregnancy-related complications (e.g. chorioamnionitis, eclampsia, recurrent pregnancy loss); however, no prior work has been done in this area in the horse. To identify pregnancy-specific miRNAs, we collected serial whole blood samples in pregnant mares at 8, 9, 10 m of gestation …

The Mare Reproductive Loss Syndrome And The Eastern Tent Caterpillar: A Toxicokinetic/Statistical Analysis With Clinical, Epidemiologic, And Mechanistic Implications, Manu Sebastian, Marie G. Gantz, Thomas Tobin, J. Daniel Harkins, Jeffrey M. Bosken, Charlie Hughes, Lenn R. Harrison, William V. Bernard, Dana L. Richter, Terrence D. Fitzgerald

Maxwell H. Gluck Equine Research Center Faculty Publications

During 2001, central Kentucky experienced acute transient epidemics of early and late fetal losses, pericarditis, and unilateral endophthalmitis, collectively referred to as mare reproductive loss syndrome (MRLS). A toxicokinetic/statistical analysis of experimental and field MRLS data was conducted using accelerated failure time (AFT) analysis of abortions following administration of Eastern tent caterpillars (ETCs; 100 or 50 g/day or 100 g of irradiated caterpillars/day) to late-term pregnant mares. In addition, 2001 late-term fetal loss field data were used in the analysis. Experimental data were fitted by AFT analysis at a high (P < .0001) significance. Times to first abortion (“lag time”) and abortion rates were dose dependent. Lag times decreased and abortion rates increased exponentially with dose. Calculated dose × response data curves allow interpretation of abortion data in terms of “intubated ETC equivalents.” Analysis suggested that field exposure to ETCs in 2001 in central Kentucky commenced on approximately April 27, was initially equivalent to approximately 5 g of intubated ETCs/day, and increased to approximately 30 g/day at the outbreak peak. This analysis accounts for many aspects of the epidemiology, clinical presentations, and manifestations of MRLS. It allows quantitative interpretation of experimental and field MRLS data and has implications for the basic mechanisms underlying MRLS. The results support suggestions that MRLS is caused by exposure to or ingestion of ETCs. The results also show that high levels of ETC exposure produce intense, focused outbreaks of MRLS, closely linked in time and place to dispersing ETCs, as occurred in central Kentucky in 2001. With less intense exposure, lag time is longer and abortions tend to spread out over time and may occur out of phase with ETC exposure, obscuring both diagnosis of this syndrome and the role of the caterpillars.