Angiogenesis and microvascular development in the marmoset (Callithrix jacchus) endometrium during early pregnancy

The aim of the study was to describe and quantify the changes in the maternal vasculature and angiogenesis during early pregnancy in the marmoset endometrium using bromodeoxyuridine (BrdU) to identify proliferating cells, CD31 to label endothelial cells and dual staining to identify proliferating endothelial cells. Non-pregnant animals from mid- and late secretory stages were studied and compared with pregnant animals at weeks 2, 3 and 4 of pregnancy. Qualitative and morphometric analyses of angiogenesis and vascular area were performed. The results show that pregnancy is associated with increasing angiogenesis in the upper zone of the endometrium, becoming significantly increased at 3 weeks. This is associated with an increase in the vessel area and diameter in this zone. These results provide the platform from which to design studies in which specific angiogenic factors can be targeted in vivo during early pregnancy in order to determine their role in regulating these vascular changes.