elements will invade, and eventually the house will disintegrate. But if you proactively take care of the structure, repair
all damage,
confront all dangers, and rebuild or renovate parts from time to time using new materials and technologies,
the life of the house can essentially be extended without limit.
The same holds true for our bodies and brains. The only difference is that, while we fully understand the methods
underlying
the maintenance of a house, we do not yet fully understand all of the biological principles of life. But with
our rapidly increasing comprehension of the biochemical processes and pathways of biology, we are quickly gaining
that knowledge. We are
beginning to understand aging, not as a single inexorable progression but as a group of related
processes. Strategies are emerging for fully reversing each of these aging progressions, using different combinations of
biotechnology techniques.
De Grey describes his goal as "engineered negligible senescence"—stopping the body and brain from becoming
more frail and disease-prone as it grows older.
18
As he explains, "All the core knowledge needed to develop
engineered negligible senescence
is already in our possession—it mainly just needs to be pieced together."
19
De Grey
believes we'll demonstrate "robustly rejuvenated" mice—mice that are functionally younger than before being treated
and with the life extension to prove it—within ten years, and he points out that this achievement will have a dramatic
effect on public opinion. Demonstrating that we can reverse the aging process in an animal that shares 99 percent of
our genes will profoundly challenge the common wisdom that aging and death are inevitable. Once robust
rejuvenation
is confirmed in an animal, there will be enormous competitive pressure to translate these results into human therapies,
which should appear five to ten years later.
The diverse field of biotechnology is fueled by our accelerating progress in reverse engineering the information
processes underlying biology and by a growing arsenal of tools that can modify these processes. For example, drug
discovery was once a matter of finding substances that produced some beneficial result without excessive side effects.
This process was similar to early humans' tool discovery, which was limited to simply finding
rocks and other natural
implements that could be used for helpful purposes. Today we are learning the precise biochemical pathways that
underlie both disease and aging processes and are able to design drugs to carry out precise missions at the molecular
level. The scope and scale of these efforts are vast.
Another powerful approach is to start with biology's information backbone: the genome. With recently developed
gene technologies we're on the verge of being able to control how genes express themselves.
Gene expression is the
process by which specific cellular components (specifically RNA and the ribosomes) produce proteins according to a
specific genetic blueprint. While every human cell has the full complement of the body's genes, a specific cell, such as
a skin cell or a pancreatic islet cell, gets its characteristics from only the small fraction of genetic information
relevant
to that particular cell type.
20
The therapeutic control of this process can take place outside the cell nucleus, so it is
easier to implement than therapies that require access inside it.
Gene expression is controlled by peptides (molecules made up of sequences of up to one hundred amino acids)
and short RNA strands. We are now beginning to learn how these processes work.
21
Many new therapies now in
development and testing are based on manipulating them either to turn off the expression
of disease-causing genes or
to turn on desirable genes that may otherwise not be expressed in a particular type of cell.
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