What is the longest living animal on earth? You may be thinking whales, tortoises or sharks perhaps? And in human terms they can live pretty long lives, some well over 100 years. But have you ever heard of the Antarctic glass sponge that can apparently live for more than 10,000 years; or how about the immortal jellyfish?
Humans like to think we are the most important and evolved species on earth, but when it comes to longevity we are lightweights. The good news is that we are the only species that are extending our life expectancy; 100 years ago humans could only expect to live about 50 years, today that has expanded to 71. The maximum human life span, on the other hand, has remained about the same.
A study published in Nature last year caused an outcry when it suggested that the human lifespan was capped at about 115 years. Many scientists have disputed this, adding their own research to the argument.
The latest news, a report published in Nature* in July, suggests we can expand this by at least 10 to 15%; the study team claim to have achieved what the human race has been chasing for so long - the reversal of the aging process… at least in mice.
The study’s findings confirm that aging is controlled by an area in the brain called the hypothalamus. More specifically, stem cells produced in this area of the brain control the aging process in some way. These stem cells are present in the hypothalamus from birth but slowly decline as we age, until they are almost completely absent by middle-age.
In the initial stages of the study about 70% of these stem cells were killed off in the hypothalamus of young mice, resulting in rapid aging and a decline in health. Then stem cells were implanted into the hypothalamus of a sample group of aging mice; the health and physical fitness of these mice improved and they lived up to 15% longer than the control group.
The stem cells are neural stem cells, they secrete molecules called microRNAs (miRNAs) that appear to control gene expression in processes involved in aging.
The next step in this research is to generate human neural stem cells and ultimately move to implanting these into the hypothalamus of humans, in the hopes of increasing health and fitness and slowing the aging process. The thoughts of having something implanted into my brain does not remotely appeal to me, but I suspect, when it comes to clinical trials, the team will have little difficulty finding willing participants.
If brain implantation is not your thing, how about a little bit of telomere extending? Our genetic code is contained within our chromosomes, which have protective caps on their ends, called telomers. Every time our cells replicate these telomers shorten. There are many research studies that are focusing on extending these telomers and thereby increasing the longevity of the cells within our bodies. Although definite advances have been made in this area of research, other complications arise, such as a possible increased risk of cancer.
If implants and extensions sound too invasive then there is still plenty of research suggestion less extreme ways to prolong our lives. Some are obvious, like staying away from processed foods and following a healthier diet. When it comes to exercise it is recommended that we get at least 150 minutes of it a week, and, if one study is to be believed, that includes shopping, with claims that those that shop daily reduce the risk of death by more than 23%.
If you are a parent then the mere sex of your children, or the number of children you have, may influence how long you live. With studies claiming that dads of girls live long than dads of boys (74 weeks longer per daughter born) and mums of twins have a greater chance of longevity.
Depending on which studies you follow there are certainly plenty of life-expanding options to choose from. However for some the holy-grail of longevity is to take away all limits, to achieve immortality. And maybe that will be a real possibility in the future, perhaps with a little technical enhancement.
There are many terms and options, from transhumanism, cybernetic immortality or virtual immortality but, whatever term you choose for the fusing of humans with machine, they seem to be ever closer to becoming a reality.
Maybe it all comes down to how we define life; it seems that some scientists focus on consciousness as the root of living, at least that would explain their enthusiasm to fuse our brains with something a little less organic. There are many options being studied, from the basic uploading of consciousness to a computer, to the combining of our brain in a virtual realm.
If you want to take it a step further you could look at investing in a custom made avatar, all ready to receive your brain once your current body stops performing.
Science may be catching up with science fiction, but then you have to consider the question… immortality may be OK for a jellyfish, but will it really suit the human race?
Yalin Zhang et al., ‘Hypothalamic stem cells control ageing speed partly through exosomal miRNAs’ Nature (2017)