C E Quinn1, C Folkard, J Detmar, R F Casper. 1. Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Institute of Medical Sciences, University of Toronto, 150 Bloor St W, Suite 210, Toronto, ON, Canada, M5G 1X5.
Abstract
BACKGROUND: Understanding the mechanisms by which fluid absorption and secretion occur in the endometrium is clinically important since conditions that deregulate this process reduce fertility. It has been suggested that luminal epithelial cells induce a crucial step in the process of embryo implantation called uterine closure via endocytotic fluid uptake. Uterine lumen closure is a key step in the process of embryo implantation and is absent in some infertile strains of mice. METHODS: To investigate the process of uterine closure a ferritin-based tracer, used as a marker of endocytosis, was injected into the uterine lumen on day 5 of pregnancy when closure occurs. RESULTS: Unexpectedly, luminal epithelial uptake of tracer was minimal on day 5 of pregnancy discrediting endocytosis as the induction method of uterine closure. In contrast, ferritin was found deep in the stromal portion of the endometrium in pre-pregnant animals. CONCLUSIONS: We have shown for the first time that uterine closure is not induced by luminal epithelial cell driven endocytosis. Another novel finding of this study was the passage of the tracer ferritin up to 15 cells deep into the endometrium suggesting an as yet unstudied mechanism by which information can be transported from the uterine lumen to the underlying stroma.
BACKGROUND: Understanding the mechanisms by which fluid absorption and secretion occur in the endometrium is clinically important since conditions that deregulate this process reduce fertility. It has been suggested that luminal epithelial cells induce a crucial step in the process of embryo implantation called uterine closure via endocytotic fluid uptake. Uterine lumen closure is a key step in the process of embryo implantation and is absent in some infertile strains of mice. METHODS: To investigate the process of uterine closure a ferritin-based tracer, used as a marker of endocytosis, was injected into the uterine lumen on day 5 of pregnancy when closure occurs. RESULTS: Unexpectedly, luminal epithelial uptake of tracer was minimal on day 5 of pregnancy discrediting endocytosis as the induction method of uterine closure. In contrast, ferritin was found deep in the stromal portion of the endometrium in pre-pregnant animals. CONCLUSIONS: We have shown for the first time that uterine closure is not induced by luminal epithelial cell driven endocytosis. Another novel finding of this study was the passage of the tracer ferritin up to 15 cells deep into the endometrium suggesting an as yet unstudied mechanism by which information can be transported from the uterine lumen to the underlying stroma.
Authors: Susanne Tranguch; Joyce Cheung-Flynn; Takiko Daikoku; Viravan Prapapanich; Marc B Cox; Huirong Xie; Haibin Wang; Sanjoy K Das; David F Smith; Sudhansu K Dey Journal: Proc Natl Acad Sci U S A Date: 2005-09-21 Impact factor: 11.205
Authors: Andrea Abbing; Ulrich K Blaschke; Swen Grein; Michael Kretschmar; Christoph M B Stark; Michael J W Thies; Jürgen Walter; Martina Weigand; Diemuth C Woith; Jürgen Hess; Christian O A Reiser Journal: J Biol Chem Date: 2004-04-21 Impact factor: 5.157