title: Equine endometrial vascular pattern changes during the estrous cycle examined by Narrow Band Imaging hysteroscopy.
abstract: The aim of this study was to evaluate the uterine blood supply and endometrial vessel architecture, during the equine estrous cycle. Narrow Band Imaging (NBI) hysteroscopy was used for evaluating changes in the endometrial vasculature during the estrous cycle [six mares, d 0 (representing the day of ovulation), d 6 and 11 in four locations]. In addition, endometrial biopsy samples were used for immunodetection of markers for angiogenesis (Vascular Endothelial Growth Factor A, its receptor 2, as well as angiopoietin-2 and its receptor-tyrosine-kinase Tie2) during the estrous cycle (three mares, d 0, 5 and 10; one biopsy per mare). Detailed analysis of hysteroscopic images revealed an increase in the vascular density from estrus towards diestrus. In contrast, microscopic specimens prepared from biopsies revealed no evidence for changes in the endometrial vessel number during the estrous cycle. Studies on expression of angiogenesis markers indicated that cyclic changes in the endometrial vascular density observed by NBI-hysteroscopy were not due to formation of new vessels. It is concluded that vessels are involved in blood supply of a smaller area during diestrus, facilitating better distribution of nutrients during this phase.
authors.affiliation: Institute for Reproductive Biology, University of Veterinary Medicine Hannover, Bünteweg 2, 30559 Hannover, Germany. Electronic address: Henning.Otzen@tiho-hannover.de.
authors.forename: Henning
authors.initials: H
authors.lastname: Otzen
authors.affiliation: Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Bünteweg 15, 30559 Hannover, Germany. Electronic address: Harald.Sieme@tiho-hannover.de.
authors.forename: Harald
authors.initials: H
authors.lastname: Sieme
authors.affiliation: Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Bünteweg 15, 30559 Hannover, Germany. Electronic address: Harriette.Oldenhof@tiho-hannover.de.
authors.forename: Harriëtte
authors.initials: H
authors.lastname: Oldenhof
authors.affiliation: Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Bünteweg 15, 30559 Hannover, Germany. Electronic address: Ana.Kassens@tiho-hannover.de.
authors.forename: Ana
authors.initials: A
authors.lastname: Kassens
authors.affiliation: Clinic for Horses-Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Bünteweg 15, 30559 Hannover, Germany. Electronic address: Franziska.Ertmer@tiho-hannover.de.
authors.forename: Franziska
authors.initials: F
authors.lastname: Ertmer
authors.affiliation: Institute for Anatomy, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, 30173 Hannover, Germany. Electronic address: Kristina.Rode@tiho-hannover.de.
authors.forename: Kristina
authors.initials: K
authors.lastname: Rode
authors.affiliation: Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 33, 04103 Leipzig, Germany. Electronic address: kristin.mueller@vetmed.uni-leipzig.de.
authors.forename: Kristin
authors.initials: K
authors.lastname: Müller
authors.affiliation: Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 33, 04103 Leipzig, Germany. Electronic address: kristin.klose@vetmed.uni-leipzig.de.
authors.forename: Kristin
authors.initials: K
authors.lastname: Klose
authors.affiliation: Institute for Biometry, Epidemiology and Information Processing, University of Veterinary Medicine Hannover, Bünteweg 2, 30559 Hannover, Germany. Electronic address: Karl.Rohn@tiho-hannover.de.
authors.forename: Karl
authors.initials: K
authors.lastname: Rohn
authors.affiliation: Institute of Pathology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 33, 04103 Leipzig, Germany. Electronic address: schoon@vetmed.uni-leipzig.de.
authors.forename: Heinz-Adolf
authors.initials: HA
authors.lastname: Schoon
authors.affiliation: Institute for Reproductive Biology, University of Veterinary Medicine Hannover, Bünteweg 2, 30559 Hannover, Germany. Electronic address: Burkhard.Meinecke@tiho-hannover.de.
authors.forename: Burkhard
authors.initials: B
authors.lastname: Meinecke
mesh_terms: D042702:Angiopoietin-2 / Q000378:metabolism; D000818:Animals; D004717:Endometrium / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D006736:Horses / Q000378:metabolism; D015907:Hysteroscopy / Q000379:methods / Q000662:veterinary; D062048:Narrow Band Imaging / Q000662:veterinary; D011247:Pregnancy; D042787:Receptor, TIE-2 / Q000378:metabolism; D014599:Uterus / Q000098:blood supply / Q000000981:diagnostic imaging; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D042702:Angiopoietin-2; D042461:Vascular Endothelial Growth Factor A; D042787:Receptor, TIE-2; D040301:Vascular Endothelial Growth Factor Receptor-2
keywords: Angiogenesis; Blood vessel; Endometrium; Endoscopy; Mare; NBI