title: Impaired placental vasculogenesis compromises the growth of sheep embryos developed in vitro.
abstract: To evaluate how assisted reproductive technologies (ART) affect vasculogenesis of the developing conceptus, we analyzed placental and fetal development of in vitro-produced (IVP) sheep embryos. Pregnancies produced by ART carry increased risk of low birth weight, though what causes this risk remains largely unknown. We recently reported that developmental arrest of sheep conceptuses obtained by ART is most pronounced when the cardiovascular system develops (Days 20-30 of development). A total of 86 IVP blastocysts (2-4 per ewe) were surgically transferred to 30 recipient sheep 6 days after estrus; 20 sheep were naturally mated (control). Conceptuses were recovered from sheep at Days 20, 22, 26, and 30 of gestation and morphologically evaluated. Then, the conceptuses and part of their placentae (chorion-allantois) were fixed for histological and immunohistochemical analysis and snap-frozen in liquid nitrogen for subsequent mRNA expression analysis. Results demonstrate that the cardiovascular systems of sheep IVP conceptuses were severely underdeveloped. Pericardial and placental hemorrhages were noted in a majority (5/7) of the dead embryos. In the surviving IVP embryos, the expression of angiogenetic factors was reduced at Day 20. The placental vessels were underdeveloped on Days 20 and 22 (P < 0.05), though placental vasculogenesis was successfully completed on subsequent days. However, low vessel number persisted at Days 26 and 30 (4.6 vs. 5.9 and 6.64 vs. 8.70 per field, respectively; P < 0.05) together with reduced vessel diameter at Day 26 (46.89 vs. 89.92 μm; P < 0.05). In vitro production of sheep embryos induced severely impaired vasculogenesis early in gestation. This may lead to developmental programing problems, such as intrauterine growth restriction of the fetus, resulting in long-term health consequences for the offspring, such as cardiovascular diseases.
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Fidanza
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Toschi
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Zacchini
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Czernik
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Palmieri
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: PierAugusto
authors.initials: P
authors.lastname: Scapolo
authors.affiliation: Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland.
authors.forename: Jacek A
authors.initials: JA
authors.lastname: Modlinski
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy.
authors.forename: Pasqualino
authors.initials: P
authors.lastname: Loi
authors.affiliation: Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland gptak@unite.it.
authors.forename: Grazyna E
authors.initials: GE
authors.lastname: Ptak
mesh_terms: D000818:Animals; D004624:Embryo Transfer / Q000662:veterinary*; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D047109:Fetal Development / Q000502:physiology*; D010920:Placenta / Q000098:blood supply*; D010929:Placentation / Q000502:physiology*; D011247:Pregnancy; D012756:Sheep
keywords: assisted reproductive technology; developmental origins of health and disease; fetal growth; in vitro embryo culture; placenta; placental vasculogenesis; pregnancy