I AM writing from the perspective of a neurobiologist, who has been working in the area of neural Regeneration for over 20 years.
This has led to a concerted research program in the past five years investigating an adult stem cell. I am writing, therefore, in the context of technological developments in adult stem cell biology.
These developments, I believe, alter the context of the current debate by providing serious alternatives to embryonic stem cells for cell transplantation, for investigation of disease, and drug discovery. In this context, the potential of adult stem cells alters the political debate.
Adult stem cells have made considerable advances and there are numerous clinical trials throughout the world using adult stem cell therapies. Most, but not all, are experimental at this stage but the lack of use of embryonic stem cells in clinical trials illustrates the continuing problems associated with embryonic stem cells, including immune rejection and uncontrolled growth.
Multipotent stem cells have now been isolated from bone marrow, skin, tooth pulp, fat tissue and brain. In our lab we have isolated an adult stem cell from the organ of the sense of smell in the human nose. These are neural stem cells, related to those found in the brain.
We have, however, been able to induce these adult stem cells to become liver cells, heart cells, muscle cells, kidney cells, blood cells, fat cells and numerous other cell types indicative of a very broad developmental potential and far exceeding the expectations of an adult stem cell with the ability only to repair the tissue of origin. We are exploring the utility of these cells in animal models of disease and injury, including spinal cord injury, Parkinson’s disease and Motor Neuron disease.
We are not alone in using adult stem cells for these purposes and there are many groups around the world using bone marrow stem cells, for example, in cell transplantation therapies. There are numerous clinical trials of bone marrow stem cells for cardiac repair after heart attack.
In most reports there is an improvement of function after stem cell transplantation. Adult stem cells have the advantage that they can, in many cases, be taken from the same patient who needs the repair, obviating immune rejection issues.
Another example of a developing therapy is the use of olfactory ensheathing cells for the treatment of spinal cord injury. These are specialised cells, not stem cells, from the nose, that show promise for treating spinal cord injury in animal studies. We are currently undertaking a Phase I clinical trial taking these cells from the nose of the patient, growing them in the lab, and transplanting them into the injury spinal cord of human paraplegics.
It is often stated that therapeutic cloning will be required to investigate the biology of certain diseases and to find cures for them by studying embryonic stem cells and their progeny derived from the patients.
Therapeutic cloning is a long and laborious procedure and will produce an inexact “copy” of the donor because of the handful of genes passed on through the donor egg. An alternative source of stem cells for these important investigations is provided by adult stem cells.
In our lab we already have over 40 adult cell lines derived from persons with schizophrenia, Parkinson’s disease, motor neuron disease, and mitochondrial disease. These are relatively easily obtained and easy to grow in the lab in large numbers.
In the case of adult stem cells and embryonic stem cells, knowledge of the one will illuminate knowledge of the other but the ethical issues raised by the embryonic stem cell debate should be informed by knowledge of alternative technologies.
Adult stem cells currently appear to offer many advantages over embryonic stem cells. It is important that the public and politicians be kept informed of developments in all areas.
Alan Mackay-Sim is a professor at Griffith University’s School of Biomolecular and Biomedical Science