Angiogenesis in implantation.
OBJECTIVE
Implantation failure and early pregnancy loss are common following natural conceptions and they are particularly important clinical hurdles to overcome following assisted reproduction attempts. The importance of adequate vascular development and maintenance during implantation has recently become a major focus of investigation.


METHODS
Review of current published literature was undertaken to summerize the cells and cell products that regulate tissue vascularity during implantation.


RESULTS
Vascular development at the maternal fetal interface can be regulated by a number of different cell types; two principal candidates are trophoblast and natural killer cells. A wide range of soluble factors, some with well established angiogenic functions as well as other more novel factors, can contribute to vascular development and maintenance at the maternal-fetal interface.


CONCLUSIONS
Robust vascular development occurs during implantation and early placentation of normal pregnancies. Studies to define the extent and mechanisms by which defects in vascularity contribute to human implantation failure and early miscarriage need to be undertaken.
Torry
Donald S
DS
Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, P.O. Box 19626, Springfield, IL 62794-9626, USA. dtorry@siumed.edu
Leavenworth
Jonathan
J
Chang
Miao
M
Maheshwari
Vatsala
V
Groesch
Kathleen
K
Ball
Evan R
ER
Torry
Ronald J
RJ
D010064:Embryo Implantation / Q000502:physiology*; D004717:Endometrium / Q000098:blood supply* / Q000378:metabolism; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000502:physiology; D011247:Pregnancy; D042442:Vascular Endothelial Growth Factors / Q000502:physiology
D042442:Vascular Endothelial Growth Factors