Stem cells are undifferentiated cells which are capable of giving rise to many different cell types, and as such they may play a vital role in the future treatment of degenerative conditions. They are found in the developing fetus and can also be collected from umbilical cord blood soon after birth. There are some types of stem cell found in adults, but these tend to be harder for researchers to work with as they do not grow so well in the laboratory and their ability to differentiate is usually limited to just a few cell types.
Embryonic stem cells in clinical trials
Clinical trials are underway using cell lines originating from embryonic stem cells in the treatment of conditions of the nervous system. In the UK, stem cells are being used to treat stroke victims, and a concurrent trial in the US is studying the use of stem cells in spinal cord injury patients. Both trials commenced during October 2010 and will assess the safety of the process and gather preliminary data as to whether these therapies are likely to be effective.
The use of embryonic stem cells as the origin of cell lines for therapeutic use is highly controversial, as the source of the stem cells is aborted fetuses. The cell lines being used for the current trials each originated from a single donation of embryonic tissue so future donations will not be necessary to sustain these applications, but embryonic stem cells continue to be used to develop new cell lines for different therapeutic uses.
Umbilical cord blood stem cell research
Researchers have long been aware of the potential of umbilical cord blood to yield stem cells for possible therapeutic use (Broxmeyer et al, 1989). There are many potential advantages of harvesting and storing stem cells from cord blood for use in the future. Stem cells from cord blood can be isolated without the need for loss of life, so the process is much less controversial. Stem cells from a particular individual could provide the potential for therapy of that same person in the future without the risk of immunological problems.
Potential uses of umbilical cord stem cells
Early research suggests therapy using umbilical cord stem cells may be successful for a wide range of conditions. Kogler et al (2004) reported that stem cells collected from a human placenta could give rise to a wide range of cells including hematopoietic and neural cells.
Umbilical cord stem cells have been shown to aid recovery from stroke in rats (Vendrame et al, 2005). Together with other research studies, this indicates that there is a chance umbilical cord stem cells may be useful in the treatment of neurodegenerative conditions and neural damage in the future.
Cord blood cells may also have beneficial effects in the treatment of cardiovascular disease in the future. Ma et al (2004) demonstrated that treatment with human cord blood stimulated the development of new blood vessels following myocardial infarction in mice. Early clinical trials suggest infusion with cord blood may help in the treatment of type 1 diabetes (Haller et al, 2008).
Umbilical cord blood collection
Collection of cord blood in the UK has taken place since 1996. The NHS Cord Blood Bank is a public bank and donations are used for research and to treat patients with conditions such as leukaemia, blood disorders and immunodeficiencies. Donations can only be made at certain hospitals where suitably trained staff can ensure the procedure is completed correctly and safely.
Collecting and storing umbilical cord blood for private use is more controversial. Only a tiny proportion of donations are likely to be used, but many parents are eager to invest in cord blood banking in order to ensure their child has the best chance of benefiting from future medical advances. Collection of cord blood for private use is heavily regulated, and the American Academy of Pediatrics (AAP) actively discourage the practice, partly because of fears that cord stem cells used to treat future malignancies in the same individual may already display pre-malignant tendencies (AAP policy report, 2007).
HE Broxmeyer, GW Douglas, G Hangoc “Human Umbilical Cord Blood as a Potential Source of Transplantable Hematopoietic Stem/Progenitor Cells” Proceedings of the National Academy of Science 86:3828-3832 (1989)
G Kogler, S Senkson, JA Airey “A New Human Somatic Stem Cell from Placental Cord Blood with Intrinsic Pluripotent Differentiation Potential” The Journal of Experimental Medicine 200:123-135 (2004)
M Vendrama, C Gemma, D de Mesquita “Anti-Inflammatory Effects of Human Cord Blood Cells in a Rat Model of Stroke” Stem Cells and Development 14:595-604 (2005)
N Ma, C Stamm, A Kaminski “Human Cord Blood Cells Induce Angiogenesis Following Myocardial Infarction in NOD/scid-mice” Cardiovascular Research 66:45-54 (2004)
MJ Haller, HL Viener, C Wasserfall “Autologous Umbilical Cord Blood Infusion for Type 1 Diabetes” Experimental Hematology 36:710-715 (2008)
NHS Cord Blood Bank website
AAP Policy Statement “Cord Blood Banking for Potential Future Transplantation” Pediatrics 119:165-170 (2007)