Stem cells: marvel or slippery slope?

THE planned development of a £15m science centre at Oldham Sixth-Form College sees the town bucking the national trend by having more students than ever taking the subjects.
Tonight, in the latest in a series of Friday features, we look at stem cell research and its potentially amazing benefits with Dr Pauline Balac, senior lecturer in biology at the the University of Huddersfield’s School of Applied Sciences

DO you remember the Superman actor Christopher Reeve? He was paralysed after a horse riding accident in 1995, which severed his spinal cord at the neck.

He campaigned for stem cell research, to find a treatment for spinal cord injuries, until his death in 2004. But between 2001-2006, President George Bush restricted US federally-funded embryonic stem cell research to existing cell lines only. This ban was overturned by President Obama last month. President Obama paid tribute to the late Christopher Reeve for raising the awareness of the value of stem cell research.

So what are they concerned about? Cells can be categorised into three types: labile, stable and permanent. Labile cells, such as epidermis and bone marrow have excellent regenerative properties. Stable cells such as liver, cartilage, bone and skeletal muscle do regenerate, but more slowly than labile cells. Permanent cells such as nerves, eye lenses and heart muscle have no regenerative capacity.

Stem cells are special cells that can regenerate themselves by cell division and also differentiate into a variety of specialised cell types. The two main types of stem cell are embryonic stem cells and adult stem cells.

Human embryonic stem cells are obtained from the inner mass of 4-5 day old embryos consisting of 50-150 cells. These cells can develop into any of the 200 plus cell types that make up the adult human body, so you can see why they are so potentially valuable for research.

Adult stem cells can be obtained from a number of tissues including umbilical cord blood, bone marrow and skin cells. Adult stem cells have been used for some time to routinely treat disease. Bone marrow cells are used to treat leukaemia (a cancer of the white blood cells) and skin cells are used to cover skin loss or burns.

Most people accept the use of adult stem cells in medical treatment; embryonic stem cell research is what some people find unacceptable. This is because starting a cell line requires the destruction of a human embryo.

Supporters argue that the potential benefits of stem cell treatments for cancer and neurodegenerative diseases, such a Parkinsons or Alzheimer’s, outweigh the objections.

Opponents argue that embryonic stem cell technologies are a slippery slope to reproductive cloning, which would fundamentally devalue human life.

Recently it was shown in principle that adult stem cells can be manipulated to generate embryonic stem cells lines, by the manipulation of a few key genes. It is also possible that unwanted embryos created for in vitro fertilisation (IVF) could be donated, with consent, and used for the research.

In the UK, research on embryonic stem cells has been going on quietly without any restriction on funding. This year three major stem cell studies are due to start in this country.

The first is a trial in Glasgow involving 12 patients who have been left disabled by stroke. They will have stem cells derived from human foetal tissue injected into their brains.

The eventual aim is to see if neural stem cells can repair the tissue damage. ReNeuron, the UK based company that developed the stem cell line, chose Britain in which to carry out the research after failing to get approval in the USA.

The second project, in Edinburgh, is to create synthetic blood from human embryonic stem cells. The artificial blood will be made from the stem cells of human embryos left over from IVF treatment.

Researchers will test embryos to find those that are genetically programmed to develop into the O-negative blood group, the universal donor. The benefit would be a supply of blood free from the risk of HIV and hepatitis infection.

The third study is at Bristol University, where stem cells will be implanted into 10 patients suffering from torn knee cartilage — a common injury among young sports people.

The stem cells will come from the patient’s own bone marrow, reducing the chance of rejection. The same research group transplanted a windpipe, made using the patient’s own stem cells, into a 30-year-old woman last year.

Stem cell therapy can work in one of two ways. It could repair by direct cell replacement, or it could help the body’s own repair system by secretion of growth factors. Whichever method of action is used, several obstacles need to be overcome for widespread use of human stem cells.

These problems include how to get the stem cells into the body, how to keep them alive and how to make them function correctly without causing tumours or immune rejection.

The promise of stem cell therapy for neurodegenerative disorders such as Multiple Sclerosis and Motor Neurone Disease is an exciting prospect, as these disorders are currently untreatable.

These diseases are amenable to embryonic stem cell therapy because adult nerve cells have no regenerative capacity. Christopher Reeve once told a reporter “If you came back here in ten years, I expect that I’d walk to the door to greet you”.

Maybe 10 years from now, that comment may not be too futuristic...