Scientists in the US have created human embryonic stem cells without destroying embryos, a discovery that appears to get around a basic ethical objection to stem cell research.
The breakthrough – published online by the scientific journal Nature on 24 August – could help lead to greater public funding for the field and make it more appealing for commercial investment.
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US President George Bush recently vetoed legislation that would have made state funding for embryonic stem cell research possible – an action that has been widely criticised by scientists across the globe.
However, no embryonic stem cell research is currently being done in South Africa. No formal policies exist and there's no government funding for research in this country.
But that doesn't mean South Africans aren't affected by decisions made abroad. The research done in countries such as America has the potential to change medicine as we know it.
Debate: where life begins
In order to understand the debate raging in the US, one has to go back to the origins of stem cells.
Prof Michael Pepper, director of the Netcare Institute of Cellular and Molecular Medicine in Pretoria, explains that there are two types of stem cells: 1) embryonic stem cells; and 2) adult stem cells.
The period that stretches from the moment of fertilisation up until the eighth week of pregnancy is generally regarded as the embryonic stage, while the foetal stage lasts from the eight-week mark up until birth.
Embryonic stem cells are "harvested" during the blastocyst stage – an early stage of embryonic development that consists of a hollow ball of cells with a localised thickening (called the "inner cell mass"). This ball of cells will eventually develop into the embryo.
Research shows that embryonic stem cells are remarkably useful. These cells can develop into every type of cell in the body – and has the potential to treat a myriad of diseases.
But their use is controversial, and the debate seems to be centred on the definition of the point at which life begins. According to Pepper, there are generally four ways of thinking about it:
life begins at the moment of fertilisation;
life begins when the organs start to develop;
life begins at the moment of perceived consciousness;
life begins at the moment when the foetus is able to survive outside of the womb (somewhere between 22 and 24 weeks).
"I don't know which one is correct," Pepper says. "But Bush believes that life begins at the moment of fertilisation."
In other words, the US president is of the opinion that when scientists take stem cells from the embryo during the blastocyst stage, they're taking away life.
Bush seems to oppose the fact that innocent human lives are sacrificed in the hope of finding medical benefits for others. "It crosses a moral boundary that our society needs to respect," he was recently quoted as saying.
The fact that a US biosciences company has succeeded in deriving stem cells from embryos without killing them, raises hopes that Bush will reconsider his veto on federal funding for such work.
The scientists were able to grow a stem cell line using just one or two cells from the blastocyst, making it possible for the embryo to develop as normal.
Unethical use of stem cells
Apart from the global controversy regarding the use of embryonic stem cells, these cells have also been in the news for another reason: its unethical use in the treatment of disease.
A Cape Town couple was recently accused of exploiting desperate patients by providing them with ampoules containing cord stem-cells from a registered laboratory, Die Burger reported.
There have also been reports of stem cells from animals being used in the treatment of humans.
But, according to Pepper, bone-marrow transplants are currently the only universally accepted use of stem cells.
"Any other applications are either in a legitimate experimental stage or are unethical, and aren't accepted by the medical community as a routine form of therapy," he says.
Several potential uses of stem cells are currently being investigated, but are not yet a reality in a clinical sense. Some of these applications include:
The use of stem cells in the treatment of nervous system disorders, such as Parkinson's disease, spinal cord injury and blindness.
Treating diabetes, by using embryonic stem cells to make insulin-producing beta cells.
Using stem cells in the treatment of patients with heart failure as well as in those with heart attacks.
Bone-marrow transplants
The use of stem cells for bone-marrow transplantation is used mainly in the treatment of cancer, but also in treating other diseases. This type of therapy, in which adult stem cells are used, is already popular worldwide.
Stem cells make it possible for patients to receive very high doses of chemotherapy and/or radiation therapy.
Both these treatments are aimed at dividing cancer cells. Unfortunately, healthy cells are affected too, for example the cells in the hair roots (this is why cancer patients often experience hair loss during and after treatment).
Radio- and chemotherapy also affect the cells in the bone marrow, which are responsible for producing the body's red and white blood cells, as well as the blood platelets. Without these, the body is susceptible to anaemia, infection and bleeding.
When the cells in the bone marrow are wiped out, stem cells can replace them. "After treatment, the stem cells populate the bone marrow, ensuring that these blood elements are formed again," Pepper says.
Stem cells for bone-marrow transplants can be obtained either from the patient being treated or from another individual. Sources of these stem cells include:
the bone marrow itself;
peripheral, circulating blood; and
blood from the umbilical cord.
Stem cells in SA
The practice of using stem cells in bone-marrow transplants has been applied in South Africa for years.
What is new here is that umbilical cord stem cells can now be obtained from three private stem cell banks around the country.
About the fact that no research studies on embryonic stem cells are currently being conducted here, Pepper remains positive: "I believe this will change in future as embryonic stem cell research is translated into clinical reality. The potential is enormous."
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