I have no idea what the significance of telomere is (googled it but really want a TL;DR version). Can someone explain this preliminary result in layman's terms?
Quoting wikipedia:
> During chromosome replication, the enzymes that duplicate DNA cannot continue their duplication all the way to the end of a chromosome, so in each duplication the end of the chromosome is shortened [...] The telomeres are disposable buffers at the ends of chromosomes which are truncated during cell division; their presence protects the genes before them on the chromosome from being truncated instead.
> Telomere shortening is associated with aging, mortality and aging-related diseases. In 2003, Richard Cawthon discovered that those with longer telomeres lead longer lives than those with short telomeres. However, it is not known whether short telomeres are just a sign of cellular age or actually contribute to the aging process.
It causes your body to (very) slowly lose the ability to grow new cells. Also cells with shorter telomeres "senescence", which is sort of like aging : they become slower, and more brittle.
Amongst the advantages this has is that it protects against cells that increase their metabolism too high and against cells that rapidly divide (by having them senescence and die). The obvious disadvantage: it eventually kills you.
It seems likely, given that this mechanism is "deliberate" and definitely under the control of your DNA, that you live longer and more successfully with aging than without.
Not necessarily "you" but perhaps the species as a whole. Without the aging and inevitable death our ancestors may have evolved slower.
The human body has a mechanism to reset telomere length during reproduction; i.e., babies are born with "full length" telomeres.
Can anyone shed light on why this mechanism is so hard to trigger in an adult? What are the technical difficulties in artifically lengthening telomeres?
Purely speculating, death to "old age" is rare in nature so the process merely has to be "good enough" for our genes to compete rather than perfect enough for immortality.
Clearly, as you age, telomeres would shrink to nothingness. However, there is a mechanism to add more DNA to telomeres... which seems to be off for most cells. So it's thought that shortening telomeres is a cause of cellular aging, and lengthening them is thought to be able to halt or reverse cellular aging and hence aging in general.
The actual biology experiments generally seem to suggest more "we don't really know what's going on here."
In short, what's being said is "going to space seems to show an improvement in a metric that we really, really hope is correlated with increased longevity."
Another really interesting result was in DNA methylation, a gene activity regulation process [1].
Scott's DNA methylation decreased during flight while his Earthbound twin's methylation increased during that time. After Scott's return to Earth, DNA methylation in both twins returned to baseline level. The last result puzzles me.
[1] http://ideonexus.com/2009/02/17/how-much-does-time-dilate-fo...
[2] https://spaceflight.nasa.gov/station/crew/exp7/luletters/lu_...