Amaranth

The word Amaranth comes from the Greek amarantos, the “one that does not wither,” or the never-fading (flower). The mystical notion of immortality however, may not be so mystical after all. Can we create a race of immortals? Should we? At what evolutionary cost?

Movies such as The Fountain and The Curious Case of Benjamin Button explore this fascination and challenge the perimeters of our knowledge on aging. An episode in the Television series Fringe involved an investigation into the death of a woman and her strange child. The woman was pregnant for only hours, yet the baby she birthed was fully developed- and also aged eighty years in the span of a few minutes. With each cell division, chromosomes lose a portion of their ends and lose vital information, thereby limiting cells to a fixed number of divisions. Studies have suggested that this is responsible for aging at the cellular level and sets limits on life spans. Without checkpoints during the cell cycle, this process occurs rapidly. So is it possible to enforce checkpoints and reverse aging? Obviously, Fringe is science fiction, and diseases such as Progeria cited as relevant examples of rapid advanced aging do not occur within the time-frame depicted on-screen.

However, when the last few decades have seen scientists enhance life expectancy and participate in cutting-edge research on stem cells, therapeutic cloning, etcetera, one does wonder: are prospects for life extension so wondrous as to give human life an amaranth-like nature? Can we actually fiddle with the human clock?

Two areas of research must be given due credit for opening our eyes to such a possibility: genetics and regenerative medicine.

A successful surgery for jawbone regeneration took place at the Mount Sinai Hospital in Toronto. A puddy composed of Bone Morphogenetic Protein was used to stimulate the only cells in the body that have the capability to become whatever type of cell the region needs, stem cells. At UofT, scientists have generated heart tissue with the capacity to beat naturally from stem cells. The use of embryonic stem cells (derived from the placenta after birth, or dead embryos) has been ridden with questions of morality, but with such demonstrations of the use of adult stem cells to generate new tissue, there is new hope for transplantation. The idea of having organ refills such as these reminds me of the Ewan McGregor-Scarlett Johanssen movie, The Island. Not quite as extreme though, yet.

Now genetics goes one step further. In the CBC documentary, Longevity Revolution, scientist Cynthia Kenyon talks about her research on tiny worms that reveal genes whose regulation renders individuals that live longer, healthier, more active lives. She iterates that the old view of aging being a passive process “where you just randomly fall apart like an old car with time” is being replaced by the new view of gene regulation as being capable of stalling, or even reversing aging. At the onset of genetics, scientists were of the view that all living things were derivations of their genetic blueprints. However, with studies in molecular biology and evolution, it became clear that species had common ancestry, which means we’re all derivations of a singular genetic code that accumulated differences over evolutionary time, causing species to diverge further and further. Genetics has revealed several genes encoding proteins as well as gene-regulating molecules common to many species, which is why studies on worms are also of significance to humans. Obviously, studies on mice would be even more significant, which is why the Methuselah Foundation is awarding a million dollars to the scientist that creates the longest living mouse.

A very recent development, if proven safe, will get right down to editing the genetic blueprint. The zinc finger technique will allow the insertion of new genes at a designated site. Genetically Modified Organisms are proof of successful gene insertions resulting in a desired product. And, Gene Therapy is representative of the relatively low, but existential, success of such tactics in humans. But genetic changes made in current gene therapy are to body cells, and they would die with the individual. But the zinc finger technique will alter human egg and sperm cells, making this both a heritable change, and a moral quandary. Sort of like epigenetics, the extermination of undesirable human phenotypes, sans physical murder. It is artificial selection, much like the still-controversial BT crops.

So how does it work? Functional proteins are a crucial component of molecular and cellular-level processes. They act as carriers for transport of molecules like glucose, enzymes to catalyze the many reactions for metabolism, transduction molecules to transmit hormonal signals, structural components like actin and tubulin that maintain cell shape and form. Versatile, and therefore, all-important. Now, ALL proteins develop in the same way: small units binding to form a large polymer, much like the construction of a DNA sequence: the differences occur in the types of units and the number of units. The resulting sequences are different, and they then result in differences in folding (to form the three-dimensional protein structure). Several standard 3D configurations are formed within any protein molecule, like zinc fingers and hairpin loops, that determine what all the protein can attach to, and thus, what its capabilities are. Zinc fingers have an atom of zinc that holds two loops of protein together to form a “finger.” The fingers recognize specific sequences of DNA, guiding the control proteins that can be attached to, to the exact site where their target gene begins. Hence, by stringing three or four fingers together, scientist can generate artificial proteins that match a particular site. ANY site. Since they can be linked to agents that turn on or turn off the gene, this can be deployed as a word processing system for cutting and pasting genetic text. The Zinc Finger Consortium, founded by Dr. Joung and Dr. Voytas, makes the method available free, researchers only pay for materials. This approach is currently being used to develop people’s immunity to AIDS viruses at the University of Pennsylvania. And to genetically correct stem cells taken from patients before use.

The advent of technologies that can remove maladaptations and circumspect aging obviously renders hope to those who had surrendered to fate. And while the pro-activism introduced to medicine by molecular biology is also enthralling to a student of science, it does make me wonder how far we would be willing to exploit our bodies should these possibilities become a reality.