|He also has a beard which suggests he|
is very serious about living forever.
Problem: In SENS, the only mutations that matter are the ones that cause you cancer. Other non-cancerous mutations may still occur, but are made redudant by the vast number of other cells around them. Cancer is an ageing related disease and one of the reasons the chance of dying increases as we grow old, according to this theory.
Solution: Cure cancer. It sounds obvious, but unfortunately, it's the only real way to avoid this problem. Cancer therapies are improving all the time, so it's not quite as sci-fi as it first appears. SENS specifically focuses in on your friend and mine, telomeres, in order to tackle the cancer problem.
Problem: Mitochondrial DNA mutates. This causes damage to the energy production of the cell, possibly through the release of certain harmful products. de Gray himself has actually gone back on this theory, stating that the number of mutations observed in mitochondrial DNA (about one every 7884 years) probably isn't enough to account for ageing.
Solution: Something called allotopic expression, which would involve moving the mitochondrial DNA further into the cell in order to protect it.
Problem: Over time, byproducts produced by the cell can build up and cause ageing effects. Alzheimer's disease, retinal deteriation and even liver spots are all caused by this build up of "junk"
Solution: The cell has a collection of miniature organs within it called lysosomes which function to digest unwanted molecules and byproducts. de Grey suggests adding new enzymes to the lysosomes, specifically ones from molds and bacteria that display efficient and complete digestion, in order to reduce the build up of waste products.
Problem: The same as before, but this time, outside of the cell. This can often be toxins, or other damaging substances.
Solution: Use phagocytes to clear the junk up. Phagocytes are essentially eating cells. They are actually used by the body to swarm areas of infection and absorb and digest infectious organism, but they could easily turn their hand to toxin clean up.
Problem: Whilst the majority of cells keep in a good balance of death and growth, some cells divide much slower, specifically those in the brain, heart and certain muscle tissues. As a result, over time these tissues grow weaker and cannot function properly.
Solution: Stem cells. The magical cells that can become any kind of cells around them (within reason) would be perfect for replacing cells lost over time.
Problem: This is where cells stop dividing, but don't die. This prevents other cells from dividing and causes damage to tissue over time.
Solution: Controlled cell demolition, sort of. By introducing specific genes, inventively called suicide genes, cells can be instructed to self destruct and stop blocking the replication of other healthy cells.
Problem: Cells in the body are held together by special link proteins. If too many of these cross links form between cells in a tissue, it can actually cause the tissue problems. In some cases, the high amount of bonds can cause the tissue to become brittle, weak and easier to damage.
Solution: The use of small molecule drugs and ezymes to severe the sugar cross links between the cells and tissues in order to keep them healthy.
As you can see, there are a wide number of different elements of aging covered in the SENS approach. You'll have probably noticed that some of topics I've mentioned bear quite a lot of resemblance to some of the other theories of ageing I've previously mentioned.
The idea behind SENS however, is not just to show how ageing works, but to provide an united front approach to life extension therapy. SENS gathers together all of the leading theories and works them into something of a therapy checklist; a strong approach that tackles a wide number of causes of aging.
It's not without its criticisms however. Some suggest that SENS is nothing but a science fiction wondering, and is too complex to be implemented anytime in the near future. Whilst many areas of research are undoubtable beneficial, such as cancer therapies, or stem cell research, critics claim that other areas, like alloptopic expression or crosslink destruction, are irrelevant and fanciful.
If you would like to disover more about SENS, the official website contains a large amount of indepth information.
I will finish with a video showing a TED talk that Aubrey de Grey gave back in 2006 on the topic of life extension;