Friday, October 4, 2013

A call for an international network of stem cell banks to ensure diversity and consistency in iPS cell lines

When we talk about diversity we typically think about ensuring that people from different communities are not discriminated against in society such as in the workplace or in school and that they have the same rights as everyone else. But diversity is also an important consideration in developing new stem cell therapies so that they will be effective in people from diverse backgrounds with diverse forms of a disease. A new article in the journal Cell Stem Cell explores just how important diversity is, and how we can achieve it.

Let’s back up a bit. The discovery of induced pluripotent stem (iPS) cells in 2006 by Shinya Yamanaka had a dramatic impact on stem cell research globally. The ability to take adult cells and reprogram them into an embryonic-like stem cell that could then be turned into any other cell in the body opened up a whole new approach to developing treatments for disease. These iPS cells gave us the ability to create more useful models of different diseases, and improved our ability to test drugs on those models to see which might be most effective in treating them.

Theoretically iPS cells can be used in a number of different ways, including taking a person’s own cells and reprogramming them into, say, brain cells to treat that person for a disease like Parkinson’s. Or you could create an entire line of iPS cells that could then be used to treat many different people.

But how do you ensure that those iPS cells reflect the diversity of the patients you might be treating?. We know from blood, tissue and organ transplantation that a poorly matched donation can be potentially deadly. Similar concern has to be given to ensuring that iPS cells are matched to the patient so they don’t cause more problems than they are intended to fix.

We are encountering this issue right now as we begin setting up our own iPS Cell Bank so this article in Cell Stem Cell – co-written by our President Alan Trounson, PhD – points out the many factors that have to be considered when creating this kind of resource, factors such as:

  • What markers do you need to look for to ensure the cells you give someone are compatible with their immune system
  • How many lines would you need to develop to ensure you cover as many people as possible
  • What rules and regulations do you need to ensure these standards are met, not just here in the US but around the world.

Fortunately, as well as posing questions the article also offers some solutions. For example, they calculate that with just 1,000 cell lines you could create enough different lines to be compatible with 90 percent of the population. Dr. Ian Wilmut, the lead investigator on the article, says:
“Calculations suggest that cells from approximately 150 selected people would provide a useful immunological match for the majority of people.”
They also identify the proteins on the surface of a cell that they need to screen to ensure compatibility.

The group called for international collaboration to reach agreement on a wide range of issues ranging from how to manufacture the cells, how to screen and select the best donors of tissue to make these cell lines, and how to ensure these donors understand how these cell lines will be used so they can give informed consent.
“We propose that an international network of stem cell banks working with common procedures and standards should be established now in order to provide the broadest range of immunological types. This would be a critical step in ensuring widespread availability of high quality cell therapies in the future,”
It’s been just seven years since iPS cells came onto the scene but they are already being used in clinical trials and several countries are creating their own IPS cell banks to have a steady, consistent supply of cells for research. In time the hope is that they will lead to a new generation of cellular therapies and that by considering the recommendations made in this piece that those therapies will ultimately be available for all people, regardless of their ethnicity or ancestry.

Kevin McCormack

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