Sticking with mum

Trophoblast adhesion to the uterine wall is the essential first step in embryonic implantation. Its disruption has been implicated in non-chromosomal pregnancy loss — a significant clinical concern in human reproduction — but most of the mechanisms involved in trophoblast adhesion have been unclear. In the January 17 Science, Olga D. Genbacev and colleagues at the University of California, San Francisco, USA, show that the trophoblast L-selectin mediates adhesion at the maternal-fetal interface (Science, 299:405-408, January 17, 2003).

Genbacev et al. examined endometrial biopsies from six donors during the follicular (nonreceptive) and the luteal (receptive) phases. They observed that human uterine epithelial cells up-regulated selectin oligosaccharide-based ligands during receptivity and human trophoblasts expressed L-selectin. In addition, they showed that beads coated with the selectin ligand 6-sulfo sLex bound to trophoblasts, and trophoblasts bound to ligand expressing uterine luminal epithelium in tissue sections.

"With the Genbacev et...