Dr Elizabeth Blackburn tells me that things are still rather muddled on the telomerase front. She comments:
W...an experiment was done using human cells in the test tube ... that showed that these cells could keep growing... if they were given a gene construct containing a part of the telomerase enzyme. When this gene construct was expressed - i.e. made to produce the telomerase component in the cells - (although the gene was unnaturally expressed under a non-natural control system in these cells) these cells had an extended lifespan... It now makes it more reasonable than was thought previously that telomerase action is required to keep cells dividing....
But the plot thickens more:
Now, just in the last month or so, a paper was published by David Beach and colleagues in which they have repeated the experiment using cells from a human tissue cell type different from the type used in the originally published experiment of extended life span. They now find that these other cells do not have their lifespan extended when the same experiment of expressing the telomerase gene is done.
So we're back to not knowing whether expressing telomerase really IS important in human life span.
The bottom line is that the research is really right in the middle just now - the facts are coming out bit by bit but there isn't enough known to extend the results with certainty to the whole human being.
This is perhaps a setback for hopes of enhanced longevity by that path. But clearly the ball is still in play...
Damien Broderick