Application Of Stem Cell Technology Research Articles

THE BIOLOGICAL RESTORATION OF CENTRAL NERVOUS SYSTEM ARCHITECTURE AND FUNCTION

Since their discovery, stem cells have fascinated scientists with their ultimate potential: the ability to cure disease, repair altered physiology, and reverse neurological deficit. Stem cell science unquestionably promises to eliminate many of the tragic limitations contemporary medicine must acknowledge, and cloning may provide young cells for an aging population. Although it is widely believed that stem cells will transform the way medicine is practiced, therapeutic interventions using stem cell technology are still in their infancy. The 3 most common stem cell sources studied today are umbilical cord blood, bone marrow, and human embryos. Although cord blood is currently used to treat dozens of disorders and bone marrow stem cells have been used clinically since the 1960s, human embryonic stem cells have yet to be successfully applied to any disease. Undeniably, stem cell therapy has the potential to be one of the most powerful therapeutic options available. In this introductory article of a 5-part series on stem cells, we narrate the evolution of modern stem cell science, delineating major landmarks that will prove responsible for taking stem cell technology from the laboratory into revolutionary clinical applications: from the first milestone of identifying the mouse hematopoietic stem cell to the latest feats of producing pluripotent stem cells without embryos at all. In Part 2, we present the evidence demonstrating the certainty of adult mammalian neurogenesis; in Parts 3 and 4, we describe neurosurgical applications of stem cell technology; and in Part 5, we discuss the philosophical and ethical issues surrounding stem cell therapy, as well as future areas of exploration.

Regulation of Stem Cells in the Zebra Fish Hematopoietic System

Hematopoietic stem cells (HSCs) have been used extensively as a model for stem cell biology. Stem cells share the ability to self-renew and differentiate into multiple cell types, making them ideal candidates for tissue regeneration or replacement therapies. Current applications of stem cell technology are limited by our knowledge of the molecular mechanisms that control their proliferation and differentiation, and various model organisms have been used to fill these gaps. This chapter focuses on the contributions of the zebra fish model to our understanding of stem cell regulation within the hematopoietic system. Studies in zebra fish have been valuable for identifying new genetic and signaling factors that affect HSC formation and development with important implications for humans, and new advances in the zebra fish toolbox will allow other aspects of HSC behavior to be investigated as well, including migration, homing, and engraftment.

Cowboy cloners, mavericks and kings: a cautionary tale of a promissory science

Ever since Dolly the sheep was cloned, there has been much debate in the media and public spheres about the ethics and morality of genetic research. This paper, based on a Public Lecture given at the Australian National University in Canberra in September 2006, considers some of the social and cultural issues that arise from scientific advances in the selection, modification and engineering of human and other species, and their implications for improving health and extending life. It suggests that while visionary talk abounds, the new genetics has not yet begun to fulfil its promises in these areas. Examples, based on the author's own research, range from the mapping of the human genome, and the development of proteomics, to the application of stem cell technologies in South Korea, India and the United Kingdom. In particular, the paper highlights the importance of the robust regulation of informed consent procedures to under pin good governance in these new bio-technologies. It concludes that this account is a cautionary tale of a ‘promissory science’, where experience suggests that hype may once more triumph over hope.

Application of Stem Cell Technology for Coronary Artery Disease at the All India Institute of Medical Sciences, New Delhi, India

Stem cell technology is rapidly gaining popularity as a way to improve the prognosis of patients with coronary artery disease and heart failure. In this review, we systematically analyze the basis, methods, and results of stem cell technology for coronary artery disease at the All India Institute of Medical Sciences, New Delhi, India.

From Gene Therapy and Stem Cells to Clinical Electrophysiology

Gene therapy, cell therapy, and tissue engineering are emerging as novel experimental therapeutic paradigms for a variety of cardiovascular disorders. In the current report we will review the possible implications of these emerging technologies in the field of cardiac electrophysiology. Initially, the possible role of myocardial gene and cell therapies in creating a biological alternative to electronic pacemakers for the treatment of bradyarrhythmias will be discussed. This will be followed by a description of the possible applications of using similar strategies for the treatment of common tachyarrhythmias. Finally, the electrophysiological implications of cardiac stem cell therapy for heart failure, as well as the possible in vitro applications of stem cell technology for electrophysiological studies and drug screening, will be discussed. While these emerging strategies provide a paradigm shift from conventional treatment modalities, this field is still at its infancy and several obstacles, discussed in this review, should be overcome before any clinical breakthroughs can be expected.

Advancing cartilage tissue engineering: the application of stem cell technology

The treatment of cartilage pathology and trauma face the challenges of poor regenerative potential and inferior repair. Nevertheless, recent advances in tissue engineering indicate that adult stem cells could provide a source of chondrocytes for tissue engineering that the isolation of mature chondrocytes has failed to achieve. Various adjuncts to their propagation and differentiation have been explored, such as biomaterials, bioreactors and growth hormones. To date, all tissue engineered cartilage has been significantly mechanically inferior to its natural counterparts and further problems in vivo relate to poor integration and deterioration of tissue quality over time. However, adult stem cells--with their high rate of proliferation and ease of isolation--are expected to greatly further the development and usefulness of tissue engineered cartilage.

Review:Application of Stem Cells for Vascular Tissue Engineering

As the prevalence of vascular disease has continued to expand, the need for a suitable arterial replacement has prompted researchers to look beyond synthetic and autologous grafts toward the field of tissue engineering. Advances in vascular tissue engineering have utilized both mesenchymal and hematopoietic stem cells as a cell source in an attempt to create a fully engineered small-diameter graft. Stem cells offer enormous potential as a cell source because of their proliferative and growth potential, and the application of stem cell technology has far-reaching implications for future applications. The innovative use of stem cells for vascular tissue engineering has opened new possibilities for a fully engineered blood vessel. The purpose of this review is to summarize the current perspective on the use of stem cells for vascular tissue engineering. It focuses principally on the classes of stem cells used, techniques for differentiation scaffolding technology, and the successes and failures of models.

Epigenetic reprogramming in mammals

Epigenetic marking systems confer stability of gene expression during mammalian development. Genome-wide epigenetic reprogramming occurs at stages when developmental potency of cells changes. At fertilization, the paternal genome exchanges protamines for histones, undergoes DNA demethylation, and acquires histone modifications, whereas the maternal genome appears epigenetically more static. During preimplantation development, there is passive DNA demethylation and further reorganization of histone modifications. In blastocysts, embryonic and extraembryonic lineages first show different epigenetic marks. This epigenetic reprogramming is likely to be needed for totipotency, correct initiation of embryonic gene expression, and early lineage development in the embryo. Comparative work demonstrates reprogramming in all mammalian species analysed, but the extent and timing varies, consistent with notable differences between species during preimplantation development. Parental imprinting marks originate in sperm and oocytes and are generally protected from this genome-wide reprogramming. Early primordial germ cells possess imprinting marks similar to those of somatic cells. However, rapid DNA demethylation after midgestation erases these parental imprints, in preparation for sex-specific de novo methylation during gametogenesis. Aberrant reprogramming of somatic epigenetic marks after somatic cell nuclear transfer leads to epigenetic defects in cloned embryos and stem cells. Links between epigenetic marking systems appear to be developmentally regulated contributing to plasticity. A number of activities that confer epigenetic marks are firmly established, while for those that remove marks, particularly methylation, some interesting candidates have emerged recently which need thorough testing in vivo. A mechanistic understanding of reprogramming will be crucial for medical applications of stem cell technology.

Stem cells: Implications for urology

Stem cells are characterized by their potential immortality and are capable of self-renewal and differentiation. Stem cells are proposed to provide the potential to cure degenerative diseases and to give important clues regarding human development and aging. However, stem cell research has evoked enthusiasm and passionate debate regarding the ethics of their use in medicine and reproduction. In this article, the current understanding of the biology of stem cells, their application in urology, and some of the controversies regarding their use are discussed. Although the clinical application of stem cell technologies to urologic practice is likely to be well in the future, advances in this field hold great promise for the correction of a number of illnesses. Nevertheless, scientists and ethicists will continue to struggle with their ethical responsibilities to the patient and society.

Britain the first to formally ban human cloning

The British government announced in April that it would ban all forms of human reproductive cloning. This makes Britain the first country to do this and comes as part of a package of legislation designed to allay fears regarding misuse of genetic technologies. The health secretary, Alan Milburn, announced the comprehensive ban on human cloning along with a moratorium on the use of genetic data by insurance companies and an increased availability of genetic screening tests on the UK National Health Service. Two new national laboratories for research into diagnostics and treatments for genetic disorders are also to be established. The cloning ban signifies a clear demarcation between the application of stem cell technologies for therapeutic research, which is allowed in Britain, and the use of such technologies in the creation of cloned humans. D.S.