Before 2007,  the research community had dogmatically insisted that only embryonic stem cell research would be medically useful, and that adult stem cell research was a waste of resources and effort.  The contentious debate was framed as between "enlightened" scientists and religious fundamentalists.

Like many dogmatic theoretical constructs--this one proved to be false.

The Institute of Science and Society reports that researchers at Edinburgh and Cambridge Universities in the UK reported that existing stem cells in the adult brain can be stimulated by a drug to repair damage in animal models of multiple sclerosis (MS).

"This proof-of-principle experiment suggest that there is little scientific advantage in deriving embryonic cells for tissue repair when naturally existing adult stem cells can do the job, with minimum intervention and without raising ethical concerns."

"Adult stem cells are showing greater and greater promise in providing a more ethical alternative to embryonic stem cells. With the discovery of more and more resident stem cells in various adult tissues, the future lies with being able to utilise these cells to perform the job that, ultimately, they are perfectly designed to do."  

If the viability of using adult stem cells to repair damaged tissue--including damaged brain cells--is proven--without unforeseen disastrous consequences-- then we will have resolved both the moral concerns of a significant segment of the population, as well eliminating the complex, high risk medical issues involved in transplanting organs or embryonic stem cells. 

 Vera Hassner Sharav

Stem Cells Repair without Transplant

Existing stem cells in the adult brain stimulated by drug to repair brain damage in animal models of multiple sclerosis Dr. Eva Sirinathinghji

There has been a great deal of excitement over the recent discovery that stem cells (see Box) with the potential to multiply indefinitely and generate many other different kinds of cells can be created from ordinary skin cells (see [1] The Promise of Induced Pluripotent Stem Cells, SiS 50). These ‘induced pluripotent stem cells’ (iPS cells) could be used to repair damaged tissue. For example, they can be turned into the types of brain cells – cholinergic neurones – that are thought to die early on in Alzheimer’s disease [2].

Although iPS cells may be useful for modelling diseases, their potential for regenerative therapy, as with embryonic stem cells, is still limited. The dangers of tumour formation following transplantation, as well as the requirement for brain surgery, on top of the little evidence of success in animal and human studies, are some of the major concerns regarding stem cell therapies for brain diseases.

In contrast to the use of exogenous stem cells for brain repair, researchers at Edinburgh and Cambridge Universities in the UK reported earlier that naturally existing stem cells in the adult brain can be stimulated by a drug to repair damage in animal models of multiple sclerosis (MS) [3].

This proof-of-principle experiment suggest that there is little scientific advantage in deriving embryonic cells for tissue repair when naturally existing adult stem cells can do the job, with minimum intervention and without raising ethical concerns (see [4] No Case for Embryonic Stem Cells Research, and other articles in the series, SiS 25).

Stem cells for therapy

Since the first derivation of human embryonic stem (hES) cells in 1998 [5],  stem cell therapies have been investigated for a wide range of medical conditions from heart disease, diabetes, spinal cord injury, retinal disorders, stroke, as well as neurodegenerative diseases including Parkinson’s, Huntington’s disease and MS. A great deal of research to date has focused on the use of embryonic stem cells derived from human embryos for regenerative repair; though clinical success has only been reported for using the patient’s own adult stem cells (see [6] Patient's Own Stem Cells Mend Heart, SiS 25).

More recently, however, research based on utilising endogenous brain stem cells (a person’s own cells) has gained ground. Such a strategy can avoid all ethical issues associated with deriving stem cells from embryos. It also avoids the scientific complications of using embryonic cells grown in long-term culture, where their full cellular identity and capacity to differentiate into different kinds of cells, migrate and functionally integrate into patients bodies is still limited or unknown. Embryonic stem cell cultures are also notoriously unstable, showing genetic imbalances over time, and also have potential to develop into tumours [3]. Furthermore, stem cell transplantation can require serious surgical procedures that are risky and expensive. Surgery on the brain would be best avoided under any circumstances, considering it is the most complicated, as well as least understood organ in our body.

This is an exciting approach to regenerative repair, and could be applied to many different diseases, not just those affecting the brain. Work on heart disease has also made progress in this area, where a recent paper showing that haematopoietic stem cells produced in adult bone marrow, can be pharmacologically manipulated to repair heart tissue following myocardial infarction (heart attack) in mice [9]. By giving a molecule to the mice that mobilised stem cells from the bone marrow into blood circulation, along with a drug to protect its degradation, the stem cells were able to successfully reach the heart. This work led to generation of new blood vessels, improved cardiac function, and increased survival, offering hope in treating one of the biggest killers in the world, safely and affordably.

Adult stem cells are showing greater and greater promise in providing a more ethical alternative to embryonic stem cells. With the discovery of more and more resident stem cells in various adult tissues, the future lies with being able to utilise these cells to perform the job that, ultimately, they are perfectly designed to do.

A fully referenced version of this article is posted on ISIS members website and is available for download here