ABSTRACT
Workshops are an important part of the IFPA annual meeting as they allow for discussion of specialised topics. At IFPA meeting 2011 there were twelve themed workshops, five of which are summarized in this report. These workshops related to various aspects of placental biology: 1) immunology; 2) epigenetics; 3) comparative placentation; 4) trophoblast differentiation; 5) stem cells.
Subject(s)
Health Status , Placenta/physiology , Animals , Biomedical Research/trends , Cell Differentiation , Epigenesis, Genetic , Female , Fetal Proteins/genetics , Fetal Proteins/metabolism , Gene Expression Regulation, Developmental , Humans , Immunomodulation , Male , MicroRNAs/physiology , Physiology, Comparative/trends , Placenta/cytology , Placenta/immunology , Placentation , Pregnancy , Pregnancy Proteins/genetics , Pregnancy Proteins/metabolism , Stem Cell Transplantation/trends , Stem Cells/cytology , Stem Cells/immunology , Trophoblasts/cytology , Trophoblasts/immunologyABSTRACT
Most lizards lay eggs. However viviparity has evolved in the Squamata on many separate occasions by the process of extended retention of the egg coincident with gradual loss of the eggshell. This process is linked to reduction of the amount of yolk which is coupled with development of placental nutrient transfer. The family Scincidae currently show a range of multiple independent origins of viviparity and placentation along this pathway, and the genus Mabuya shows one of the most structurally complex placentas. This study investigates the transport potential of the different areas of the Mabuya placenta using immunocytochemistry to localize the systems in place for calcium, glucose and water transfer. The localization of these transporters demonstrated restricted distributions in the specialized areas of this morphologically complex placenta.
Subject(s)
Aquaporins/metabolism , Calcium-Binding Proteins/metabolism , Glucose Transporter Type 1/metabolism , Lizards/metabolism , Viviparity, Nonmammalian , Actins/metabolism , Animals , Calcium/metabolism , Female , Glucose/metabolism , Immunohistochemistry , Keratins/metabolism , Lectins/metabolism , Water/metabolismABSTRACT
Analysis of placentation in the final stages of development in Mabuya mabouya shows that the placenta is formed by the apposition of the chorioallantois to the uterine mucosa implicating the entire embryonic chamber, because the allantoic vesicle invades all the exocoelom. The chorioallantoic placenta presents the features proper of a type IV allantoplacenta. However, in the mesometrial area peripheral to the placentome, we found that the paraplacentome is an additional zone specialized for histotrophic transfer, and is separated from the rest of the embryonic chamber by a chorionic invagination formed of polymorphic cells. The chorionic areolae are components of the embryonic hemisphere; they are in apposition to an endometrium with columnar epithelial cells and several glands that secrete toward the cavity of the areolae. They are observed only in the preparturition stage, probably operating in maternal-fetal transfer of nutrients during the last embryonic growth stage. The mesometrial hemisphere possesses specializations related to histotrophic nutrition (placentome, paraplacentome, and chorionic areolae), while in the abembryonic hemisphere there is an allantoplacenta of mixed function, with capacity for histotrophic nutrition and for gas exchange. The absorptive plaques are small rounded areas constituted by chorionic cells similar to the paraplacentomal chorionic cells, in intimate apposition with a secretory uterine epithelium. Separating the absorptive plaques are respiratory segments histologically similar to the type I allantoplacenta. The additional histotrophic areas found for this species demonstrate the great specialization of this allantoplacenta, and support the highest degree of matrotrophy among reptiles reached in the Neotropical Mabuya.
