Transcript Time’s Arrow: Projecting Human Lifespan in the 21st Century

http://www.census.gov/population/www/pop-profile/natproj.html.
Accessed 2/5/12
https://www.cia.gov/library/publications/the-world-factbook/rankorder/2102rank.html
Am J Public Health. 2008; 98: 1163–1166.
Science 2002; 296: 1029-31
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Telomere length
Oxidative damage
Caloric restriction
Gene expression
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Nucleotide sequences at the end of a
chromosome, which protects the end of the
chromosome from deterioration
These sequences shorten in length as cell age
and make them vulnerable to mutation and
death
Expanding the length of telomeres with drugs
or by gene therapy may be a way of
extending lifespan
Am J Hum Biol 2011;23:149-67
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Theory holds that reactive oxygen species
(ROS) which can damage cell DNA
accumulate as humans age, leading to the
degeneration of organ systems and
susceptibility to disease characteristic of
aging
Could drugs reverse
process?
Am J Physiol Regul Integr Comp Physiol 2007; 292: R18–R36
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Currently a vibrant area of research
Numerous studies at the cellular and animal
level have suggested a 20% decrease in
caloric intake can extend life
◦ Data in numerous animal models including
primates
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The big question is WHY?
◦ More chronic disease?
◦ Genetic adaptability (i.e. a “leaner, meaner”
organism?
Eur J Clin Invest. 2010;40: 440–450
Science. 2009;325: 201–204.
Science. 2009;325: 201–204.
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Some data suggest that 25% of human
lifespan is heritable (found in twin studies)
Studies to find the “long-life” gene have been
inconclusive
– Maybe more than one gene?
– Responsible for different regulatory assignments
• Cytokine production—Responsible for immunogenic
responses
• NK receptor genes—Responsible for cancer
surveillance
• Etc
Int J Immunogenet. 2011;38:373-81
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Mammalian Target of rapamycin (mTOR) is a
gene derived kinase that is a central
controller of cell growth, metabolism and
aging
Implicated in a wide variety of human disease
Rapamycin administration may inhibitor
amount of mTOR in tissues, PERHAPS
decreasing development of disease
Animal and human studies underway
Curr Opin Cell Biol. 2011;23:744-55.
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Therapeutic cloning
◦ Technology available, but how to turn cellular
machinery off??
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Stem-Cells
◦ Use in diseased organs? Data to date has been
disappointing
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Nanotechnology
◦ Molecular sized “machines” to target cancer cells or
remove atherosclerosis?
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Although difficult to project, the increase in
American lifespan is predicted to continue
into the 21st Century
New Technologies MAY dramatically cause a
shift in these numbers, but no indications at
this time strongly suggest this
Stay tuned for research in this area
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