Stem Cell Biology
Stem cell biology is a fascinating and relatively new area of life sciences research. By increasing our understanding of how these most basic of cells lead to the development of complex tissues, organs and ultimately whole organisms we also increase the possibility of stem cell-based therapies eventually being used to treat a number of degenerative diseases.
For the most part, scientists work with two types of stem cell from animals and humans: embryonic stem cells and adult stem cells. Embryonic stem cells are derived from the early stage embryo, whereas adult stem cells are obtained from certain human tissues, such as bone marrow, muscle or brain. Following earlier studies of mouse stem cells, human embryonic stem cells were first isolated and grown in the United States in 1998. Stem cells, whatever their origin, are distinguished from other cells found in the human body by a number of unique properties; namely, their ability to proliferate by dividing and renewing themselves over long periods, to differentiate and give rise to specialised cells, and the fact that they themselves are unspecialised.
A large number of questions regarding the properties of stem cells remain unanswered but are currently being investigated. For example understanding the specific factors that induce stem cell proliferation without differentiation is crucial for scientists attempting to grow large numbers of unspecialised stem cells. Furthermore, identifying the genetic signals as well as particular stimuli from the environment that trigger differentiation is essential if researchers are to grow cells or tissues for specific cell-based therapies. Another key area of research lies in the field of adult stem cell plasticity, or the potential ability of stem cells from one type of tissue to give rise to cell types of a completely different tissue. For example it has been shown that haematopoietic stem cells in the bone marrow can develop into heart muscle, and that liver cells can be induced to produce insulin. Adult stem cells therefore hold great therapeutic potential.
Human stem cells have a range of applications as research tools as well as in novel therapies. An improved understanding of the molecular mechanisms that control the way in which cells grow and differentiate may yield crucial information on how conditions such as cancer develop, as well suggest new approaches to their treatment. Human stem cells could also be used to screen new drugs for toxicity and safety, by developing differentiated cell lines. But the most important application of stem cells remains in the promise they hold as potential therapeutic agents. Today, donated tissues and organs are used to replace diseased or damaged tissues, but the need for transplants far exceeds the available supply. Stem cells, differentiated into specific cell types offer the possibility of a renewable source of replacement cells and tissues that could be used to treat a range of conditions including Alzheimer’s disease, stroke, diabetes, burns and heart disease.
However a number of barriers to fully exploiting the therapeutic potential of stem cells remain. Technical hurdles such as understanding and controlling the factors necessary to stimulate differentiation, the generation of sufficient quantities of the desired tissue for transplantation, and ensuring that these function appropriately are just some of the issues that must be addressed. Additionally, a range of regulatory, legal and ethical concerns must also be tackled when considering the future of stem cell medicine. It is hoped that the East of England Stem Cell Network will bring together not just scientists and clinicians but also those with expertise in law, social science and bioethics, and will stimulate research activity and its translation into clinical application within an ethically sound framework.
