An interesting article regarding the theories of one Aubrey David Nicholas Jasper de Grey, a computer scientist turned self-taught natural scientist turned theoretical biogerontologist. He theorizes that there are 7 obstacles to immortality (heavily excerpted below):

1. Loss and atrophy or degeneration of cells. This element of aging is particularly important in tissues where cells cannot replace themselves as they die, such as the heart and brain.

2. Accumulation of cells that are not wanted. These are (a) fat cells, which tend to proliferate and not only replace muscle but also lead to diabetes by diminishing the body’s ability to respond to the pancreatic hormone insulin, and (b) cells that have become senescent, which accumulate in the cartilage of our joints.

3. Mutations in chromosomes. The most damaging consequence of cell mutation is the development of cancer.

4. Mutations in mitochondria. Mitochondria are the micromachines that produce energy for the cell’s activities. They contain small amounts of DNA, which are particularly susceptible to mutations since they are not housed in the chromosomes of the nucleus.

5. The accumulation of “junk” within the cell. The junk in question is a collection of complex material that results from the cell’s breakdown of large molecules. Intracellular structures called lysosomes are the primary microchambers for such breakdown; the junk tends to collect in them, causing problems in the function of certain types of cells. Atherosclerosis, hardening of the arteries, is the biggest manifestation of these complications.

6. The accumulation of “junk” outside the cell. The fluid in which all cells are bathed—called extracellular fluid—may come to contain aggregates of protein material that it is incapable of breaking down. The result is the formation of a substance called amyloid, which is the material found in the brains of people with Alz­heimer’s disease.

7. Cross-links in proteins outside the cell. The extracellular fluid contains many flexible protein molecules that exist unchanged for long periods of time, whose function is to give certain tissues such qualities as elasticity, transparence, or high tensile strength. Over a lifetime, occasional chemical reactions gradually affect these molecules in ways that change their physical and/or chemical qualities.

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p>A lot of the article is devoted to the author’s impression of de Grey himself…I honestly haven’t yet finished it, but it’s nevertheless an interesting idea that immortability, by this man’s estimate, may be achievable in 25 years. Via Slashdot.