Stem Cells Quotes

“Haematopoietic stem cell transplantation is not a term that is immediately recognizable to the general public but it is actually the same as the much more familiar ‘bone marrow transplantation’. The rather long phrase haematopoietic stem cell transplantation (HSCT) is now preferred because it covers not just transplantation of bone marrow itself but other types of transplant where the blood-forming (haematopoietic) stem cells of the graft come from non-marrow sources such as peripheral blood or umbilical cord blood. Worldwide, about 50,000 HSCTs are carried out each year making this overwhelmingly the most important type of stem cell therapy in current practice. Most are done for treatment of cancer, mainly lymphomas and leukaemias, with about 5 per cent for treatment of non-malignant blood diseases and a few other conditions.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“Despite the restriction of stem cells to just two regions of the mammalian central nervous system (CNS)—the lateral ventricle linings and the dentate gyrus—it is possible to grow neural stem cells in tissue culture from a much wider range of brain regions than this. The stem cells grow in a form called neurospheres. These are clumps of cells, up to 0.3 mm wide, that grow in suspension culture in a medium containing two specific growth factors (EGF and FGF). The cultures can be initiated from any part of the foetal CNS and often from parts of the adult CNS as well, even regions not thought to undergo continuous renewal. Neurospheres are thought each to contain a few neural stem cells, which are capable of self-renewal, plus a certain number of transit amplifying cells, that have finite division potential. When neurospheres are plated on an adhesive surface in the presence of serum, they will differentiate and form the three cell types normally generated by neuronal stem cells, which are neurons, and two types of glial cells: astrocytes and oligodendrocytes. If neurospheres are dissociated into single cells, a few per cent of these cells can establish new neurospheres, with similar properties to the original. Repeated cycles of dissociation and growth can provide substantial expansion capacity.

The phenomenon of neurospheres is an example of the fact that cells may behave in a different manner in tissue culture from in vivo. Neurospheres have created enormous interest because, unlike haematopoietic stem cells, they are expandable in vitro, and because there is a hope that they might be used for cell therapy of the very intractable neurodegenerative diseases involving widespread neuronal death.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“The Karolinska lab has surmounted all the technical problems and published studies on several tissues. In the brain they isolated nuclei from neurons of the cerebral cortex, the part of the brain responsible for higher functions. The results indicate that there is no renewal of neurons whatsoever. All the cerebral cortex neurons were formed during foetal life and they are not added to after this time, at least not enough to alter the isotope ratio. So, despite the fact that certain other areas of the brain do show some cell renewal, for the all important cerebral cortex we really are living with our lifetime supply of cells from the time of birth. This is one reason why neurodegenerative diseases are so devastating: when central neurons die, nothing can bring them back.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“There are also some potential safety concerns with grafts derived from pluripotent cells. Although Parkinson’s disease is a distressing condition that causes much suffering, it does not greatly reduce lifespan, so the period of time available for the development of complications is quite long, perhaps about 20 years on average. For any cell therapy derived from pluripotent stem cells there is always an issue about the possibility of persistence of a few pluripotent cells in the graft which might give rise to teratomas. Although the animal experiments indicate that the teratoma risk is very low, the long survival time of Parkinson’s patients does make even a very small cancer risk seem significant. Moreover, the differentiation protocols for pluripotent stem cells never produce 100 per cent of the desired cell type. Even if all the pluripotent cells are gone there will certainly be other types of neuron and glial cell present and these may generate unwanted effects. For example, the uncontrolled movement problems seen in some of the foetal midbrain graft recipients has been ascribed to the presence of other types of neuron which make inappropriate connections.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“Human pluripotent stem cells are considered a suitable source of dopaminergic neurons because the supply of early human foetuses as graft donors is limited. Also, since they are obtained as a result of elective abortion, there are inevitably some ethical issues. Abortion is opposed by more people than oppose the use of human preimplantation embryos to grow embryonic stem cells. So there is a significant body of opinion who consider it is all right to use human embryonic stem cells but not all right to use human foetal grafts. Accordingly, Parkinson’s disease is usually listed among the priority diseases for treatment with human ES cells, or more recently, with iPS cells.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“Ironically, in the Middle Ages, before the discovery of the human sperm and eggs, the Catholic Church taught that the soul entered the human foetus at the time of quickening, when the mother can first feel the foetus move inside her. But this is about 18–24 weeks of gestation, well after the time at which most abortions are performed, and even longer since the foetus was a preimplantation embryo, so this teaching has been quietly forgotten.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“The properties of the renewal tissues enabled the original definition of stem cell behaviour in terms of the ability to self-renew and to generate differentiated progeny. But the most famous stem cell of them all is now the embryonic stem cell (ES cell). In one sense, the ES cell is the iconic stem cell. It is the type of stem cell that has attracted all of the ethical controversy, and it is what lay people are thinking of when they refer to ‘stem cell research’. But ironically, the embryonic stem cell does not exist in nature. It is a creature that has been created by mankind and exists only in the world of tissue culture: the growth of cells in flasks in the laboratory, kept in temperature-controlled incubators, exposed to controlled concentrations of oxygen and carbon dioxide, and nourished by complex artificial media. Cells grown in culture are often referred to by the Latin phrase in vitro (in glass, since the relevant containers used to be made of glass) and distinguished from in vivo (inside the living body).”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“The FDA will accept a certain level of risk for a new treatment that is to be applied to a group of very sick patients who would otherwise die in the near future, but not for a group who have a relatively long life expectancy on the basis of existing therapies.”
― Jonathan Slack, Stem Cells: A Very Short Introduction

“For better or worse, we live in a world where money can be acquired simply by attracting attention and by making promises.”
― Jonathan Slack, Stem Cells: A Very Short Introduction