SpringerBriefs in Stem Cells For further volumes: http://www.springer.com/series/10206 wwwwwwwwwww Sibel Yildirim Dental Pulp Stem Cells Sibel Yildirim Department of Pediatric Dentistry Selcuk University, Faculty of Dentistry Konya , Turkey ISSN 2192-8118 ISSN 2192-8126 (electronic) ISBN 978-1-4614-5686-5 ISBN 978-1-4614-5687-2 (eBook) DOI 10.1007/978-1-4614-5687-2 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2012948961 © Author 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, speci fi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on micro fi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied speci fi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a speci fi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) To Natasha McCarthney wwwwwwwwwww Preface The pace of scienti fi c life continues to speed up considerably due to the fl ow of data being faster than ever. In my previous SpringerBrief’s preface, I mentioned the groundbreaking discovery that neutrinos have been shown to exist at speeds faster than that of light. However, only a few months after this, the discovery team debunked their data by announcing that a loose fi ber optic cable had introduced a delay in their timing system which explained the effect. Now a new subatomic par- ticle consistent with the long-sought Higgs Boson has been discovered, despite the conservative approaches of many physicists. Unfortunately, only those in the fi eld commonly recognize key discoveries in cell biology. One of the unexpected discoveries in stem cell biology is induced pluripo- tent stem cell (iPSC), which shifted the long-held paradigms of biology to a new dimension. There are many more such discoveries in biology that have been pub- lished in high-impact journals without any discernible effect on society at all, even temporarily. For example, it has been shown that plant miRNAs could migrate into a host’s blood and tissues via the normal intake of food. Eating “material” might mean eating the “information,” which supports epigenetic regulation concepts. Moreover, stem cell fates are starting to be understood with the aid of nonlinear dynamics: mathematics is now working hand in hand with cell biology. These and many other discoveries have not attracted the importance they well deserve in wider society. Media coverage referencing stem cell research and development is increasing rapidly to the extent that hardly a day goes by without hot-topic news items about them. This unfortunately also makes it very hard to distinguish fact from fi ction. Creating bio-organs and almost magical possibilities to cure cancer and other criti- cal diseases are featured regularly in the daily news. Likewise, for many dental practitioners, their wildest dream now is to build a new bio-tooth, aided by the magic of stem cells. Whether dental stem cells have any ability at all to generate a tooth now or in the future is not the main concern of this book. Rather, I am inviting the readers to understand that there are still many challenges waiting in the shadows of the dental stem cell fi eld. For example, that dental pulp-stem cells are not mesen- chymal, but mesectodermal stem cells. vii viii Preface The high costs incurred by dentistry education force its professionals to require high earning positions immediately after graduation. I believe this is the most important factor resulting in the rare occurrence of tooth-related discoveries, since dental surgeons with PhD quali fi cations are decreasing in numbers due to turbulent economic circumstances especially in developing countries. Also, compared to the late eighteenth and early nineteenth centuries, basic dental sciences are not so popu- lar currently, worldwide. In fact, teeth and the oral environment comprise one of the most sophisticated and complex adaptive systems of the human body. Teeth have to resist constant bacterial attacks from the mouth’s environment, cope with extreme temperature changes, and withstand forces of considerably high pressure during chewing. Moreover, the rigid mineralized tissue of the tooth, dentin, surrounds the highly specialized mesenchymal tissue, dental pulp. The pulp–dentin complex creates an integrated organ that displays unique interactions between a mineralized and soft tissue with a signi fi cant regenerative capacity. The very con fi ned and small dentin–pulp organ provides enormous scope for the studies of development, differentiation, regeneration, immune-regulation/immune- modulation, epigenetics, genomics, proteomics, and other fi elds. Routinely dis- carded due to extraction, permanent and exfoliated primary teeth should be evaluated for these studies, since they are ethically and politically free human tissues. Additionally, they can be obtained noninvasively. Dental pulp cells easily provide access to suitable material for the study of cell biology’s many aspects, including clinical applications. I am deeply grateful to Bruce Rutherford for his generous and humble guidance during the whole of my scienti fi c career. I am also grateful for the opportunity to have worked with Kamil Can Akçali, Jeremy Mao, Thimios Mitsiadis, Alp Can, Misako Nakashima, and with so many brilliant minds throughout my career. Thanks to John Dawson for his effort in reading the manuscript and sharing his brilliant ideas, even while on his once in a lifetime holiday. Thanks to my editor Aleta Kalkstein (Springer, USA) and assistant editor Renata Hutter for their supportive and kind assistance. I am very much appreciative of my family for their efforts, encouraging me to become a more down-to-earth person. And last but not least, thanks to Muammer Saglam for giving me an unquenchable fl ambeau and for his unconditional love that guided me to fi nd my unique way. Konya, Turkey Sibel Yildirim Contents 1 Dental Evolution ...................................................................................... 1 1.1 Historical Perspectives ..................................................................... 1 2 Tooth Development ................................................................................. 5 2.1 Stages of a Tooth Development ....................................................... 6 2.1.1 Initiation ............................................................................... 7 2.1.2 Bud Stage ............................................................................. 7 2.1.3 Cap Stage ............................................................................. 8 2.1.4 Bell Stage ............................................................................. 9 2.2 Odontoblast Differentiation ............................................................. 9 2.3 Dental Papilla and Follicle ............................................................... 12 2.4 Formation of Permanent Dentition .................................................. 13 3 Dental Pulp Is a Connective Tissue ....................................................... 17 3.1 Histology of the Dental Pulp............................................................ 17 3.2 Extracellular Matrix of Dental Pulp ................................................. 17 3.3 Cells of the Dental Pulp ................................................................... 18 3.3.1 Odontoblasts ........................................................................ 18 3.3.2 Fibroblasts ............................................................................ 19 3.3.3 Undifferentiated Mesenchymal Cells ................................... 20 3.3.4 Immunocompetent Cells ...................................................... 20 3.4 Neuronal and Vascular Networks ..................................................... 21 3.5 Deciduous (Primary) Tooth Dental Pulp .......................................... 21 4 Dental Pulp Stem Cells (DPSC) ............................................................. 25 4.1 Evidence for Dental Pulp Stem Cells: Emergence of a New Generation of Odontoblast-Like Cells ............................. 25 4.2 Origin of Progenitor Cells ................................................................ 26 4.3 Dental Pulp Stem Cells (DPSC) ...................................................... 27 4.4 DPSC from Deciduous Teeth Pulp .................................................. 28 4.4.1 The Degree of Resorption of the Teeth Related to Stem Cell Isolation........................................................... 29 ix x Contents 4.5 Niche(s) in Dental Pulp .................................................................... 33 4.6 Epigenetics in Dental Pulp ............................................................... 36 5 Isolation Methods of Dental Pulp Stem Cells ....................................... 41 5.1 Isolation of Dental Pulp Stem Cells ................................................. 41 5.1.1 Enzyme Digestion Method .................................................. 42 5.1.2 Outgrowth Method ............................................................... 42 5.2 Cell Culture Media for Dental Pulp Stem Cells............................... 44 5.3 Cryopreservation of DPSC............................................................... 49 6 Characterization of DPSC ...................................................................... 53 6.1 Phenotypic Characteristics ............................................................... 53 6.2 Multidifferentiation Capacity ........................................................... 54 6.2.1 Problems in Adipogenesis.................................................... 55 6.2.2 Odontogenic Differentiation ................................................ 56 7 Reprogramming of DPSC to Induced Pluripotent Stem Cells ........... 65 7.1 Is Reprogramming Necessary for Dental Regenerative Therapies? .................................................................. 68 8 Immunomodulatory Effects of DPSC ................................................... 73 9 Dental Pulp Is a Complex Adaptive System ......................................... 75 9.1 Changing Concepts in Cell Biology ................................................ 75 9.2 The Tooth as a Complex Adaptive System ...................................... 76 10 Conclusions .............................................................................................. 79 About the Author ............................................................................................ 81 Index ................................................................................................................. 83