Hitting Rewind II
Date: March 26, 2007
Time: 3:43am est

A couple weeks ago I was talking about one of the most promising alternative sources of human "pluripotent" stem cells called direct cell reprogramming. It holds out the possibility of producing embryonic-like stem cells, but without destroying, harming, or even involving human embryos in the process.

Reprogramming (also called de-differentiation) proposes to take adult cells from the human body and send each cell's nucleus back to a pluripotent state, meaning that each of these cells would then be capable of producing any tissue type in the human body-virtually equivalent in versatility to human embryonic stem cells.

Direct cell reprogramming offers the possibility of turning a normal adult body cell into a cell with the properties of an embryonic stem cell, but without involving human embryos in the process.

Furthermore, these stem cells would be genetically matched to the person who donated the body cells. They could then be used to grow tissues for future use in tissue replacement therapies (everything from regeneration of damaged heart tissue to Parkinson's to spinal chord injury). A perfect genetic match, these tissues would not be rejected by the donor's immune system. Most importantly, there would be no embryo created, destroyed, damaged or used in any way at any point in the process.

As I mentioned in the previous e-column on this topic, in August 2006, the journal Cell published research by a Japanese team of researchers lead by Shinya Yamanaka. In that research, Yamanaka reported successes in reprogramming mouse cells by altering just four genetic factors in those cells. In so doing, the team was able to demonstrate that the new cells had pluripotent-like qualities.

I recently asked Westchester Institute senior fellow Dr. Markus Grompe to comment on the significance of Yamanaka's work and whether anyone has yet replicated it? Here's what Markus had to say:

Nobody has yet published a replication of this work, although I have not yet heard anyone cast serious doubt on it either. Yamanaka is making all of his protocols and reagents available. The work is highly significant, because it suggests that pluripotent cells can be made from adult cells without using oocytes, embryonic stem cells or any other fetal/embryonic material. The method involves direct genetic manipulation of the adult cells with the goal of reprogramming its epigenetic state. It is also significant, because it implies that tissue-matched pluripotent cells can be generated for individual patients.

Markus further confirmed that perhaps as many as 50 labs around the world, and upwards of 200 stem cell researchers, are currently pursuing cell reprogramming. He also confirmed that, if successful, cell reprogramming holds out the same promise as so called "therapeutic cloning", meaning that the end product-patient-specific, genetically matched tissue-would be similar if not identical to what scientists would hope to achieve through cloning. When I asked him how long it would likely take before we see published research on successful attempts to do this with human cells, he prognosticated 2008 or 2009 at the latest-but was quick to add: "Success is in the eye of the beholder, however."

***