Managing diseases using stem cells

Published in The Hindu on February 21, 2008

Cell based diseases such Parkinson’s, Alzheimer’s and diabetes were seen as the first candidates for being cured using stem cell transplantation. There is a probability that it would be possible one day. But some scientists are beginning to think that it will take another 15 years for a treatment using stem cells for Parkinson’s to emerge.

“The brain is so complex. We don’t understand every phenomenon in the brain,” said Colin McGuckin, Professor of Regenerative Medicine at the Newcastle Centre for Cord Blood, Newcastle, U.K. while explaining why it will take such a long time.

And unlike other organs, such as the heart, where the stem cells can be easily introduced, getting the stem cells into the brain poses an additional challenge.

Treating organs

According to Prof. McGuckin, treating organs and not cell-based diseases, may become a reality some time in the future. Even in the case of organs, such as the heart, the central idea is not about curing but managing the disease.

And if it were to come true, it would mark a paradigm shift in the way stem cells are seen as a treatment/cure option for many diseases.

The Newcastle centre has been in the forefront of cord blood stem cell research. The Centre was the first in the world to produce cord blood-derived embryonic stem cells, liver and pancreatic-like tissues, and neural cells from cord blood stem cells. It has a public cord blood bank started seven years ago and has about 1,000 samples.

Beta cell implant

Even in the case of diabetes, Prof. McGuckin feels that cord blood stem cells may only be able to treat diabetes. They may not be able to cure it.

The strategy is to implant beta cells that produce insulin anywhere near the blood system and allow these to control blood sugar. The strategy is the same for both Type 1 and Type 2 diabetes.

“The patient would get better [with the implant]. “Diet control is a must [even after the implant],” he stressed, “sensible diet is the best way to control diabetes. In both the cases, the implant is seen as a short term therapy.

The Newcastle centre is not looking at using cord blood stem cells for treating or curing diseases alone.

They have been using stem cells to produce human tissues to study the way certain diseases manifest and progress and look for possible ways of curing or treating them.

The team has already found that some genes expressed only at the embryonic stage, when growth is at its peak, reappear later in life. Ideally these genes should not be expressed after the foetal stage. But when they do appear, it results in cancerous growth.

Genes reactivated

“These genes are reactivated [at a later stage] by accident, Prof. McGuckin said. The Newcastle team found that some cancers of the skin, lung and prostate are caused this way. They have developed a family of drugs that can slow down such cancers.

“When we slow down cancer, we can use less of chemo and the chemo will have more time to act [on the cancer],” he said while explaining the advantages of slowing down cancer.

“Can’t cure cancer”

Apart from leukaemia, can stem cells be used to cure cancers? “Stem cells can’t cure cancer; they [stem cells] really don’t fight. The cancer cells would ignore stem cells as they don’t respect the environment,” said Prof. McGuckin emphatically. “We don’t promote stem cells for cancer [treatment].”

While some cancers are caused by faulty genes within the cells, some are switched on by other cells. Animal studies are currently underway to test the drugs that can address cancers caused by both, the faulty genes and by other cells.

Finding the causal factor, as in this case, is one of the uses of studying human tissues produced using stem cells. Using them for testing new molecules for treating diseases is another promising area.

When used prior to taking up animal trials, such human tissues can help reduce the number of animals used for testing. “Can’t [totally] replace animal testing overnight,” he stressed.

Multicentric trials

The team headed by Prof. McGuckin was in Chennai recently to explore the possibility of collaborating with institutions for undertaking joint multicentric global clinical trials using cord blood stem cells.

While using the patient’s bone marrow for treating his disease (autologous transplantation) is considered to be safe and numerous clinical trials are currently underway in India, Prof. McGuckin was critical of such trials.

“Even if it is an autologous [transplantation], we are taking the cells outside [the body] and there are chances of contamination. If it is a clinical trial, the researchers must work with other institutions abroad so that it is an international trial,” he underlined. “It is a risk if the trial is done in India [alone] and not internationally. Trials should be monitored.”

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