Stem Cell Therapy on Humans - A Prospect or A Dilemma ?

Stem Cell Therapy on Humans - A Prospect or A Dilemma?

I (NB) got a chance to discuss about the applications and viability of stem cell research with an expert. Dr. Shashi Singh (SS) is doing research on a variety of stem cells at the Centre for Cellular and Molecular Biology, Hyderabad, India. Her research focus is on mesenchymal stem cells (MSCs).

It was an opportunity to understand the opinion of scientific community as provided from horse's mouth about conducting stem cell-based research on humans.

NB.

What are stem cells?

SS.

I do not think there exists any such entity as cells that can act as stems in the growth of tissues. The term is a misnomer.

In general, there are four types of cells that could rather be called regenerative cells -

1. Embryonic, that are pluripotent.

2. Adult, like the MSCs derived from the bone marrow.

3. Cancer, which can self-renew but propagate uncontrollably.

4. Induced Pluripotent Stem Cells (iPSCs), the most recent ones, where somatic cells are induced to act like pluripotent cells via gene therapy and which can be undifferentiated and then re-differentiated to form different cell types in the organism.

NB.

How are stem cells determined to become a particular type?

SS.

We can do this by providing cell markers, which are usually different forms of green fluorescent proteins (GFPs) that can be tagged to various markers on the cell's surface.

Usually, it is a group of markers that are tagged simultaneously. This becomes the basis for cellular determination or fate.

NB.

Is it ethical to allow human clinical trials for stem cell research?

SS.

No.

Most of the ongoing stem cell research is conducted on mammals like mice and rabbits. Obviously, the probability of success in these mammals may differ from humans.

Since these stem cells can proliferate into any given cell type, the risk of carcinogenicity is high even though they can act by the desired induced functionality.

Instead of curing a wound or rebuilding a damaged organ, it may reverse its efficacy and cause side effects like cancer and physiological disorders.

NB.

Why is research on diseases like Parkinson's not living up to expectation?

SS.

It may be because for any stem cell to proliferate successfully, they need to recognize their niche.

If the niche is deleterious in nature (like in Parkinson's), the stem cells will also become deleterious eventually. This may augment the effect of Parkinson's instead of diminishing it.

A good research problem could be how to create a scaffold for such stem cells, such that they are able to recognize a normal healthy niche to substitute for the pre-existing deleterious niche such that normalcy could be revived.

NB.

Is stem cell therapy not effective in curing / controlling genetically lethal diseases?Is it not the need of the hour to save patients with such diseases?

SS.

The stem cell can come only from the organism that is to be treated. Otherwise, it has to undergo various stages of recognition before being considered as self by the patient's body cells.

While the 'self' stem cells are easier to deal with, the 'foreign' cells take time to become 'self'. This is not so useful if immediate cell therapy is required.

If a person is suffering from a genetically lethal disorder, their stem cells could be genetically lethal as well. Till now, not much can be done for such patients in terms of life-saving stem cell treatment.

Having said that, we have succeeded in testing cell therapy in less lethal conditions; generally those that involve the damaged cells of cornea and wounded tissues. These have been successfully treated with multipotent ectodermal stem cells extracted from cornea.

NB.

What about stem cell therapy for neurons?

SS.

Neurons, being senescent, are highly determined in their adult phase. They do not send any growth signals once they have fully matured. As such, any stem cell induced in such an environment will probably die or be removed as 'foreign' from its niche, rather than converting to a fresh neuron.

NB.

What is your view on the future of stem cell therapy?

SS.

I feel that the area has a huge scope to do research.

We need to clear the clutter and focus on tangible research. We can channelize our findings to work in parallel to the diagnostic needs of doctors.

We need to guide them in using stem cells properly. We need to tutor them the process of using such sensitive biological machinery that is vulnerable to damage. For example, we need to teach them how to add these cells in injection syringes and how to inject it into the body to revive damaged tissues.

All that matters is one should not defer too much from what is achievable and also consider the problem to be a grey area rather than black or white. Maybe just a small change can make big improvements on a mass level to the population.