Transvascular permeability in the blood vessels of the human placental cotyledon

1. Aims: The placental cotyledon contains an integral vascular circulation which includes arterial, capillary and venous segments. This vasculature is described as fetal, it nonetheless mediates well-differentiated transport functions involving selective exclusion of some substances and uptake of others. The permeability of the cotyledon vessels varies according to developmental stage and is under hormonal and growth factor control. We used fluorescence microscopy to analyse passage of perfused proteins across the cotyledon vessel walls. 2. Methods: Cotyledons obtained at elective term cesarean sections were per…