Reproduction Abstracts

Early pregnancy loss (EPL) affecting between 6 and 15% of equine pregnancies remains a significant issue for the £3.5 billion Thoroughbred breeding and equestrian industries. Very little is known about the causes of pregnancy failure in the horse, although it is likely to involve a multitude of failed physiological processes and/or environmental insults. Our laboratory aims to identify key mechanisms that regulate the differentiation and function of trophoblast cells in both physiologically normal pregnancies and those that fail. The chorionic girdle is a unique component of the equine conceptus comprised of trophoblast cells that give rise to the equine chorionic gonadotrophin (eCG) producing endometrial cups. The molecular mechanisms that regulate differentiation of chorionic girdle trophoblast and eCG expression remain poorly understood. We have been using a targeted approach to determine the role of bone morphogenetic protein signalling and glial cells missing 1 (GCM1) in regulation of trophoblast differentiation and eCGβ transcription. We have complemented this work with microarray studies that aim to identify novel signalling pathways and candidate transcription factors that may play a role in initiation of these two processes. In order to extend our work to investigate the functionality of trophoblast cells from failed early pregnancy, we have successfully developed new methods to obtain, isolate and culture trophoblast cells from clinical cases of early pregnancy loss. We are currently using this material to determine the incidence and characteristics of aneuploidies associated with the condition.