Saturday, June 02, 2012

Weekend Post - Stemming stem cell research?

One of the most controversial areas of scientific research in modern times is stem cell therapy. Actually, it’s only controversial because certain religiously motivated groups have decided it should be controversial, regardless of the scientific truth. In fact there’s no controversy at all if you look at the facts.

Some background would be useful. Everyone reading this was originally formed from a single human cell, an egg from your mother. Once fertilized by your father’s sperm that single cell divided into two, then four, eight and so on until your body consisted of tens of trillions of cells. Here’s the clever bit. That single original cell gave rise to an enormous range of different, specialized cells. Your body contains around 200 different types of cells that are each devoted to specific purposes. Some transmit messages in your brain, others help your heart pump blood, others exist in your liver solely to “detox” your system, others receive light in your eye. The variation is amazing but they all came from that single generic cell. They all “stem” from that single cell.

These stem cells have that amazing capability: to become other types of cells. Like that first cell from your mother that created you, they have the capacity to produce the specialist cells needed in specialized organs. One of the biggest hopes in modern medicine is to find a way of introducing stem cells into damaged or diseased tissue to grow new tissue to replace the damaged bits.

This would be revolutionary and might offer us an enormously powerful technique to help cure a range of conditions.

The controversy came from one of the original sources of stem cells for research: human embryos, either from aborted embryos or from spare embryos created during fertility treatments. I can understand how people would find this instinctivel a little distasteful but these embryos weren’t in any real sense human. They had developed no further than the blastocyst stage when the embryos consists of no more than about 100 cells. In real terms they were no more “human” than the fleshy inside bit of your tooth.

However, whether rightly or wrongly, there was considerable resistance to using embryonic stem cells in research. Former President George W Bush even banned their use in any federally funded research programs.

The good news is that it looks like we can avoid the need for embryonic stem cells entirely. Stem cells can be harvested instead from adults, avoiding any of the emotional complications arising from embryo use. In fact we’ve been using adult stem cells to treat disease for years, it was just never called that. Bone marrow transplants, most commonly used to treat leukemia, actually use the stems cells found in adult bone marrow.

Bizarrely one of the richest sources of adult stem cells is the dental pulp tissue found inside adult teeth. These stem cells could, in principle, be used to grow new heart and nerve tissue, muscle and bone. The potential is extraordinary.

It’s early days but there’s great reason to be optimistic. A recent study published in The Lancet used stem cells taken from the heart tissue of heart attack victims. The scientists cultured stem cells from this tissue and re-implanted them into the damaged heart. Four months after the procedure, those participants who had received the stem cells had a significant improvement in heart function compared to a group who had not been given stem cells. The improvement wasn’t complete, their hearts were still damaged, but every little improvement helps tremendously in heart attack patients and it shows the potential for the procedure.

A similar study in Israel, which involved introducing stem cells into the hearts of rats, confirmed that the stem cells were busy bonding with existing heart tissue. The lead researcher, Lior Gepstein from Rambam Medical Center commented to the BBC that “we have shown that it's possible to take skin cells from an elderly patient with advanced heart failure and end up with his own beating cells in a laboratory dish that are healthy and young - the equivalent to the stage of his heart cells when just born."

The potential for stem cell therapies is enormous, so long as ignorance isn’t allowed to get in the way.

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