EMBRYOLOGY – UPDATES AND HIGHLIGHTS ON CLASSIC TOPICS Edited by Luís Antonio Violin Pereira Embryology – Updates and Highlights on Classic Topics Edited by Luís Antonio Violin Pereira Published by InTech Janeza Trdine 9, 51000 Rijeka, Croatia Copyright © 2012 InTech All chapters are Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. After this work has been published by InTech, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work. Any republication, referencing or personal use of the work must explicitly identify the original source. As for readers, this license allows users to download, copy and build upon published chapters even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications. Notice Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher. No responsibility is accepted for the accuracy of information contained in the published chapters. The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book. Publishing Process Manager Romina Skomersic Technical Editor Teodora Smiljanic Cover Designer InTech Design Team First published March, 2012 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can be obtained from orders@intechopen.com Embryology – Updates and Highlights on Classic Topics, Edited by Luís Antonio Violin Pereira p. cm. ISBN 978-953-51-0465-0 Contents Preface IX Part 1 Gametes and Infertility 1 Chapter 1 Molecular Alterations During Female Reproductive Aging: Can Aged Oocytes Remind Youth? 3 Misa Imai, Junwen Qin, Naomi Yamakawa, Kenji Miyado, Akihiro Umezawa and Yuji Takahashi Chapter 2 Role of Sperm DNA Integrity in Fertility 23 Mona Bungum Chapter 3 The Epididymis: Embryology, Structure, Function and Its Role in Fertilization and Infertility 41 Kélen Fabiola Arrotéia, Patrick Vianna Garcia, Mainara Ferreira Barbieri, Marilia Lopes Justino and Luís Antonio Violin Pereira Part 2 Implantation, Placentation and Early Development 67 Chapter 4 Endometrial Receptivity to Embryo Implantation: Molecular Cues from Functional Genomics 69 Alejandro A. Tapia Chapter 5 The Actors of Human Implantation: Gametes, Embryo, Endometrium 85 Virginie Gridelet, Olivier Gaspard, Barbara Polese, Philippe Ruggeri, Stephanie Ravet, Carine Munaut, Vincent Geenen, Jean-Michel Foidart, Nathalie Lédée and Sophie Perrier d’Hauterive Chapter 6 The Role of Macrophages in the Placenta 127 Grace Pinhal-Enfield, Nagaswami S. Vasan and Samuel Joseph Leibovich VI Contents Chapter 7 DNA Methylation in Development 143 Xin Pan, Roger Smith and Tamas Zakar Part 3 Perspectives in Embryology 171 Chapter 8 Stem Cell Therapies 173 D. Amat, J. Becerra, M.A. Medina, A.R. Quesada and M. Marí-Beffa Chapter 9 Self-Organization, Symmetry and Morphomechanics in Development of Organisms 189 Lev V. Beloussov Preface Embryology is a branch of science concerned with the morphological aspects of organismal development. The genomic and molecular revolution of the second half of the 20 th century, together with the classic descriptive aspects of this science have allowed greater integration in our understanding of many developmental events. Current studies in embryology and developmental biology are not restricted to gamete formation, fertilization (in vivo or in vitro), zygote formation, early growth or the development of living organisms, but also involve investigation of the genetic control of these processes and of development itself (so called morphogenesis). Modern embryology seeks to provide practical knowledge that can be applied to assisted reproduction, stem cell therapy, birth defects, fetal surgery and other fields. This book focuses on human embryology and aims to provide an up-to-date source of information on a variety of selected topics. The book consists of nine chapters organized into three sections, namely: 1) gametes and infertility, 2) implantation, placentation and early development, and 3) perspectives in embryology. 1. Gametes and Infertility Development begins with fertilization. However, the success of fertilization depends on the ability of the gametes involved. The molecular alterations that occur in oocytes during female reproductive aging represent a controversial area of clinical interest since these changes can markedly affect human female fecundity by 40 years of age or less. This topic is discussed in chapter 1 by Drs. Imai, Qin, Yamakawa, Miyado, Umezawa and Takahashi, who review their studies and recent knowledge on female reproductive aging, as well as the possibility of preventing age-associated infertility. Infertility affects approximately 15% of all couples trying to conceive. The important subject of male fertility and the biology of male gametes are dealt with in chapters two and three. Reduced semen quality contributes to ~50% of the cases of male infertility, while there is no clear explanation for infertility in the remaining 50% of cases. In chapter 2, Dr. Bungum discusses the techniques for assessing the intactness of sperm DNA since recent molecular studies have shown that factors such as breaks in sperm DNA can contribute to male infertility. In chapter 3, Drs. Arrotéia, Garcia, Barbieri, Justino and Pereira discuss sperm epididymal maturation, i.e., the process by which X Preface spermatozoa acquire their post-testicular ability to fertilize. The embryology, structure, function and role of the epididymis in fertilization and in male infertility are also emphasized. 2. Implantation, Placentation and Early Development Fertilization is followed by pre-implantational events that lead to formation of the blastocyst which is subsequently implanted in the endometrium. The onset of endometrial receptivity to the blastocyst, trophoblast invasion and placental development involves the expression of specific genes in particular cell types. As discussed by Dr. Tapia in chapter 4, this expression is temporally regulated, with some genes being turned on or showing enhanced expression while others are down- regulated or completely switched off. Likewise, when implantation has occurred, another set of genes facilitates the continuing trophoblast invasion and placentation. In chapter 5, Drs. Gridelet, Gaspard, Polese, Ruggeri, Ravet, Munaut, Geenen, Foidart, Lédée and Perrier d’Hauterive point out that implantation of the blastocyst and placentation remain the black boxes of fertility since only 20-25% of embryos transferred to the uterus after in vitro fertilization result in a birth. As pointed out by these authors, successful implantation requires that a good quality oocyte meet a normal sperm, leading to the development of a functionally normal blastocyst able to interact with the maternal endometrium. Placental macrophages play a central role in the establishment and maintenance of pregnancy through their ability to produce a variety of endogenous mediators involved in pregnancy, as well as in parturition, lactation, local immune reactions and maternal-fetal tolerance. In chapter 6, Drs. Pinhal-Enfield, Vasan and Leibovich show that the study of placental macrophages can provide insights into normal embryonic development and the possible causes of embryo loss. DNA methylation during early embryonic development has received considerable attention. In chapter 7, Drs. Pan, Smith and Zakar describe the influence of DNA methylation in cell-lineage determination, genomic imprinting and the genesis of germ cells, as well as its role in a group of diseases related to the Developmental Origins of Health and Disease (DOHaD). 3. Perspectives in Embryology Stem cells are undifferentiated cells that can proliferate and give rise to various types of differentiating cell lines. Stem cells were discovered through a combination of studies involving early embryonic development, genetics, cell surface immunology and tissue culture. The ability of these cells to differentiate into various cell types has created numerous perspectives for their use in many fields. However, the presence of these cells raises important questions. For example, if stem cells occur in humans then why does the human body not regenerate completely? And what about stem cell therapy? Chapter 8 by Drs. Amat, Becerra, Medina, Quesada and Marí-Beffa provides . EMBRYOLOGY – UPDATES AND HIGHLIGHTS ON CLASSIC TOPICS Edited by Luís Antonio Violin Pereira Embryology – Updates and Highlights. macromolecules and cellular components, e.g., mitochondrial Embryology – Updates and Highlights on Classic Topics 4 desensitization, mitochondrial DNA mutation,