This theory of aging is related to ‘longevity genes’ that are preserved in species over millions of years. There are many such genes in humans (around 15). They are also present in primitive species like the nematode roundworms (c-elegans) and they are connected with the ‘Target of Rapamycin’ (TOR) pathway for signaling. For mammal, “mTOR” is the same as TOR.
mTOR (Mammalian target of rapamycin) is a particular protein that is engraved in humans FRAP1 gene. It is practically aimed at by a immunosuppressive drug called rapamycin. The drug has been clinically tested to treat restenosis, graft rejection and autoimmune diseases. “The mTOR pathway integrates signals from nutrients, energy status and growth factors to regulate many processes, including autophagy, ribosome biogenesis and metabolism.” (“Supplementary Facts”)
The mTOR pathway is mainly responsible for control of organism and cellular growth that are inclusive to “hormonal and nutrient signals that control various cellular processes”.
Research has proven that the mTOR pathway is associated with old-age illnesses and diseases such as cancer, atherosclerosis, cardiovascular diseases, obesity, diabetes as well as neurological disorder. The use of Rapamycin or any other sub-derived drug, mTOR pathway could be blocked and this could deliver therapeutic cure to some diseases (Study 1, Study 2, Study 3). Moreover, “Targeting mTOR signaling for cancer therapy” can soon become a feasible pathway.
Human longevity might be extended if mTOR is blocked. Research has already proven that lower level of TOR signals can prolong the potential lifespan of both worms and flies. This is achieved as mitochondrial genes are improved, and thereby it alleviates the generation of ROS (reactive oxygen species). This theory is thus related to both the “Mitochondrial damage” and “Oxidative damage” theory.
Once TOR (target of rapamycin) is inhibited, it does actually increase the life span of several living organisms according to “recent studies”. It has been found that “mTOR has an impact in regulating diseases that pop-up with age”. Also, TOR tends to have positive influence on new longevity approaches such as caloric restriction.
Needs More Research
This is a subsidiary theory on aging. There are no certain facts that inhibiting mTOR pathway has no side effects. It is expected that it will increase lifespan. Yet, there are no confirmed studies proving that blocking mTOR will absolutely produce marvelous life extension.
Nonetheless, there are possibilities that mTOR pathway can address various complex aged-diseases. For instance, there is a close-relationship among “P13K-Akt, NF-kappaB and mTOR that correlates to research on longevity” and cancer cures. In treating cancer, it appears that “down-regulation of mTOR and telomerase activity” can cause cancerous cells to apoptosis.
mTOR theory on aging is actually in an infant stage. It is certain that it produces alternatives to address longevity but it is still not a proven one. To progress further in the field it might be necessary to evaluate cross-links between cellular signaling and mitochondria.
Does the mTOR story lend light on whether mitochondrial activity is more important than cell signaling or protection against oxidation damage for determining longevity? The story actually lends light on the fact that this is the wrong kind of question to ask “Such notions are slowly giving way to a more nuanced view in which cellular signaling pathways intersect with the mitochondria, creating a two-way network of interactions between the consumer (the cell) and the supplier (the mitochondria) of energy(ref).” Instead of just focusing on the health of the inner operations of the cell or the mitochondria, perhaps we need to look more at what they are saying to each other.
References:
1. Anti- aging firewalls the science and technology of longevity.
2. PNAS
Further Reading:
1. A Road Map to Anti-Aging Theories
Anti Aging, Anti Aging Theories, Health And Aging, Longevity
Thu, Jan 7, 2010
Anti Aging, Anti Aging Theories, Health And Aging, Longevity