Wednesday 26 October 2005
Study illuminates implantation regulation, endometriosis-related infertility
Source: Annual Meeting of the American Society of Reproductive Medicine; Montreal, Canada: 15-19 October 2005
Investigating how the expression of a candidate implantation gene is regulated by ovarian hormones.
US researchers have shed light on how N-acetylglucosamine-6-O-sulfotransferase (GlcNAc-6-OST), a candidate implantation gene, is regulated, in research that could hopefully improve understanding of the infertility associated with endometriosis.
GlcNAc-6-OST is an enzyme that has a role in shaping L-selectin ligand, a signal believed to mediate recognition between the embryo and the endometrium surface. Researchers led by Lee-Chuan Kao, from the Cedars Sinai Medical Center in Los Angeles, California, USA, explored its regulation.
In vitro studies of an endometrial cell line showed that treatment with 10 nM 17-beta-estradiol up-regulated the expression of GlcNAc-6-OST 3.63-fold. The further addition of medroxyprogesterone acetate (MPA) led to a substantial, 70.5-fold, increase in its expression. In contrast, GlcNAc-6-OST expression was suppressed by MPA alone.
Kao and colleagues suggest that endometrial GlcNAc-6-OST expression is upregulated by ovarian estradiol in the follicular phase, and then further heightened by progesterone at ovulation. This could facilitate the production of the high affinity L-selectin ligand epitope believed to open the implantation window.
"My hypothesis is that this particular gene, for a yet-to-be-uncovered reason, is abnormally expressed in women with endometriosis which results in the embryo not being able to find the appropriate place to bind to the endometrium leading to a failure or defect in the implantation process," said Kao.
Posted: 20 October 2005
http://www.orgyn.com/en/news/2005/Week_42/Day_4/Study_illuminates_im.asp 
Study illuminates implantation regulation, endometriosis-related infertility 
