The Endometrial Lymphatic Vasculature: Function and Dysfunction Jane E. Girling and Peter A.W. Rogers Gynaecology Research Centre, Department of Obstetrics and Gynaecology, The University of Melbourne, Melbourne, Victoria 3052, Australia. Corresponding Author: Dr Jane E Girling Gynaecology Research Centre Department of Obstetrics and Gynaecology The University of Melbourne The Royal Women’s Hospital Cnr Flemington Rd and Grattan St Parkville, VIC 3058, Australia Email:
[email protected] Telephone: +61 3 8345 3721 Fax: +61 3 8345 3702 1 Abstract The endometrium has a complex and dynamic blood and lymphatic vasculature which undergoes regular cycles of growth and breakdown. While we now have a detailed picture of the endometrial blood vasculature, our understanding of the lymphatic vasculature in the endometrium is limited. Recent studies have illustrated that the endometrium contains a population of lymphatic vessels with restricted distribution in the functional layer relative to the basal layer. The mechanisms responsible for this restricted distribution and the consequences for endometrial function are not known. This review will summarise our current understanding of endometrial lymphatics, including the mechanisms regulating their growth and function. The potential contribution of lymphatic vessels and lymphangiogenic growth factors to various endometrial disorders will be discussed. Keywords: Blood Vessels, Decidua, Endometrium, Lymphatics, Menstruation, VEGFC, VEGFD 2 1. Introduction The endometrium has a complex and dynamic blood and lymphatic vasculature which undergoes regular cycles of growth and breakdown. These cyclic changes reflect variations in circulating sex steroids and uterine blood flow and result in cyclic patterns in tissue oxygenation, haemostasis, nutrient supply, fluid balance and leukocyte distribution. Appropriate growth and functioning of the vasculature is essential for normal endometrial function, including preparation for potential embryo implantation and subsequent pregnancy.