Cell Senescence, Cancer, Longevity, Telomeres
When Campisi was introduced to the idea that cell senescence might have something to do with aging, she was skeptical. But the more she looked at the evidence:
the more she became convinced that we had all been wrong,” says Miller, “that [senescence] had something to do with aging after all.” Perhaps the strongest evidence, published when Campisi moved to the West Coast, was her demonstration that senescent cells not only exist in vivo but also accumulate in aging tissue. What’s more, she and her colleagues have found that in culture, these nonreplicating cells are far from inert. They produce a plethora of unpleasant proteins that can, among other things, destroy the structural integrity of the tissue that surrounds them.
The ultimate experiment, however, has yet to be conducted. “The critical test would be to create an organism in which you prevent senescent cells from accumulating,” says Campisi. She and her colleagues are working on devising a system to do that test. They are developing a mouse in which an inducible promoter allows them to activate a gene that will selectively eliminate senescent cells.
.....At the same time, Campisi has also done more extensive work to shore up the connection between senescence and cancer. In experiments in tissue culture and in mice, she finds that proteins produced by senescent fibroblasts, including proteases, growth factors, and even molecules that promote angiogenesis can fuel malignancy, encouraging premalignant cells to become fully cancerous and form tumors that can kill an animal. “That was a very important observation,” notes DePinho. “Advancing age is, far and away, the most important of all carcinogens, and understanding why that is has been one of the central questions in the aging field.”
A key part of Aubrey de Grey's SENS approach to longevity is the removal of senescent cells from tissues, so that they will no longer be a source of cellular breakdown and carcinogenesis. In the SENS method, senescent cells are removed, and newer more vital cells are introduced to replace them.
This is the source for the graphic above, with explanations.
Along with cell senescence, telomere research is now one of the central focuses of research into aging and longevity. An earlier article here discussed telomeres and telomerase in more detail.
It is important for the public to understand that the different strands of longevity research that have been described by Aubrey de Grey and others, are not simply empty conjecture and speculation. They are real strategies being actively pursued by various research labs around the world.
That does not mean that SENS, or other strategies proposed thus far, will conquer aging. They are simply the best approach that has been conceived so far. It is the rate of discovery of new ideas and tools, and the increasing acceleration of the rate of applied discovery, that provides a promise of many new and wonderful discoveries for increasing healthy lifespan, and overcoming the major bio-killers.
Update: This newsrelease from Brown University points to another well known researcher in cell senescence, John Sedivy. I discussed Sedivy briefly in this post.
Hat tip William Garth Hopkins.