Preface

Stem cells in general and pluripotent stem cells in particular have gained tremendous interest in the recent years, primarily driven by the hope of finding cures for several debilitating human diseases through cell transplantation (regenerating medicine). Pluripotent stem cells have the inherent ability to reproduce indefinitely and have the capability to produce all the 220 different types of cells constituting the human body and thus offer tremendous therapeutic potentials. The isolation of human embryonic stem cells (hESCs) from embryos and their successful culture in the petrii dish in 1998 has been considered the biggest breakthrough of the 21st century. This has been followed by another remarkable breakthrough in 2006 when scientists demonstrated for the first time that such pluripotent stem cells could be produced from adult somatic tissues by reprogramming without having to use human embryos. These pluripotent stem cells are called the induced pluripotent stem (iPS) cells. Production of iPS cells has been considered as the biggest discovery of this decade. Both hESCs and iPS cells are pluripotent and are highly versatile and offer tremendous therapeutic potential for finding cures for many incurable diseases such as diabetes, Parkinson’s, Alzheimer’s, and many other diseases via stem cell therapeutic in the next decade or so.

Both ES and iPS cells are pluripotent and capable of differentiating into three primary germ layer derivatives—an important characteristic for producing healthy cells for therapeutic purposes. While there are some proofs of principle with embryonic stem cells for therapeutic approaches in animal models, two major roadblocks to their use in humans must be overcome: post-transplantation immune rejection and ethical issues. iPS cell technology addresses both concerns: it is possible to use a patient’s own somatic cells to generate therapeutic iPS cells (thus eliminating the potential for immune rejection), and they represent an acceptable alternative to the use of human embryos for stem cell production. An added benefit is that patient-specific iPS cells can be used for drug and regenerative medical research. However, there are some significant issues that need further investigations : (i) the low efficiency of cell reprogramming, (ii) the integration of viral transgenes into the somatic genome, especially oncogenes such as c-MYC and KLF4 and (iii) iPS cell can lead to tumor formation. There has been a significant progress during the last 4-5 years to address to these issues and the efficiency of reprogramming has been increasing and the non-integrating systems developed to eliminate the possibility of mutagenesis with integrating approaches.

The use of stem cells in the therapeutic field and in drug development has been of considerable interest in contemporary bioscience. In recent years our knowledge and understanding of stem cell biology and regenerative medicine has increased substantially. ESCs not only continuously divide, they are also able to differentiate into all cell types of the human body. The isolation of tissue stem cells could offer a less ethically contentious and more practical source of replacement tissue for organs that are susceptible to age-related diseases or traumatic injury. These diseases include Alzheimer’s and Parkinson’s disease, but also stroke, myocardial infarction and diabetes to mention a few. They have become a serious health problem in our societies as people now live longer. A large part of stem cell research aims to identify the ideal cell type and time point of cell transplantation. Future research will also lead to improved protocols that generate more pure populations of transplantable cells. With the continuous progress in stem cell research, modern clinical medicine is at the threshold of transformation.

Cellular therapies with products from pluripotent stem cell have the potential to treat many conditions where present conventional treatments are inadequate. As such, public expectation remains high that these novel therapies will be ‘‘panacea,’’ even though there have been few preclinical animal trials. However, recent FDA approval for two clinical trials with cells derived from hESC for spinal cord injury patients and those with macula degeneration will give a big boost once some preliminary data are made available. Therefore, there is still a significant gap between promising laboratory-based research and approved final products in this emerging field. the information generated during the last one decade on these pluripotent stem cells is compartmentalized in different journals and reports. This eBook brings together the state-of-the-art on these stem cells, compiled by reputed scientists from different part of the world who are experts in the relevant fields. The major focus of this eBook has been to bring together all aspects of pluripotent stem cells from basic biology to their use in understanding disease process, toxicology, drug discovery and towards developing therapeutics.

The major credit goes to all those who contributed scholarly written chapters on fields of their expertise to this eBook and have laid the foundation for continuous progression of innovative investigations for inquisitive minds to explore further the areas of stem cell biology that can offer respite to many debilitating human diseases for which there is no cure. Members of the stem cell lab contributed sincerely for completion of this eBook. The patience of my family, particularly my wife, Dr Kiran Sidhu greatly helped me in completing this task particularly Dr Sophia Dean who prepared the subject index and also carried out general editing. The cooperation of the Bentham Press and its staff to bring out the final form of this eBook that is more presentable and readable is appreciable.