March 29th, 2015
Judging from the field of biology, escaping death altogether is just not possible. Drastically extending the human lifespan, on the other hand, is closer than one might expect. By knocking out two genes, the lifespan of mice has already been doubled. Within a few decades, this might be possible for humans too.
No upper limit
Gerontologist Valter Longo is looking for ways to extend our lifespan. Thanks to his research, common yeast fungus (used to make bread and beer) is now able to live ten weeks . A small step for man, but a giant leap for yeast – its normal lifespan is six to seven days. If the same could be applied to humans, we would be able to live for about 800 years.
The yeast’s longevity occurred with the removal of two genes from its DNA, RAS2 and SCH9, which promote ageing in yeast and cancer in humans. In addition, a calorie-restricted diet was applied to the yeast. The reason for this is that calorie-restriction decreases the activity of pathways involving insulin-like growth factor (IGF-1), glucose and TOR (target of rapamycin), which increases an organism’s lifespan.
“We’re very, very far from making a person live to 800 years of age”
Although interesting, the lifespan of yeast is not directly relevant to human ageing and longevity. Therefore Longo and his colleagues decided to take their research one step further: they found a way to knock out the two genes in mice. As a result, the mice life expectancy was doubled. Since a mouse’s genome is 99% the same as that of a human, this result seems promising. We won’t be around to meet the first 800-year old person, unfortunately. “We’re very, very far from making a person live to 800 years of age,” Longo says, “I don’t think it’s going to be very complicated to get to 120 and remain healthy, but at a certain point I think it will be possible to get people to live to 800. I don’t think there is an upper limit to the life of any organism.”
Aubrey de Grey is also specialised in gerontology, but is looking for other ways to battle the process of ageing. The technologist-turned-biologist believes getting old to be a disease; and a curable one at that. So how do we define aging? It’s quite simple: ageing is the lifelong process that gives rise to debilitation in old age. To put it in other words: there is a set of damage, types of molecular and cellular change in the body, that accumulate throughout life as intrinsic, unavoidable side effects of normal essential metabolic processes, like breathing for instance. “Most people think of ageing as the right thing to die off,” De Grey explains, “but actually, this supposed distinction between ageing on the one hand, and the diseases of old age on the other hand, is a false distinction. The only reason why diseases of old age are in fact diseases of old age, is because they’re the last stages of processes that go on throughout our whole life.”
“I’m not god- I’m a practical guy”
These are the processes De Grey would like to stop, or even better, reverse. In order to do so, he co-founded SENS Foundation, an organisation which works to develop, promote and ensure widespread access to rejuvenation biotechnologies which comprehensively address the disabilities and diseases of ageing. “Most of our people are researchers,” De Grey says, “they work in the laboratory, developing the technologies that we will put together to make comprehensive rejuvenation possible. In the first instance, hopefully in the next six to eight years, we will be able to do this in mice. What I mean by ‘do this’, is that we will take middle-aged mice, in whom nothing has been done before, and ‘repair’ them with the help of stem cell therapies, gene therapies, and vaccines. This way we will fix all of the various types of damage that accumulate during ageing. The purpose of this is to extend their healthy lifespan. Once we’ve done this, it’s only a matter of time before we can do this to humans.” This, however, does not mean that De Grey is ‘a merchant of immortality,’ as he is often dubbed. “I’m not god- I’m a practical guy. I’m working to stop people from getting sick, however old they get. Maybe people will live a long time as a result, but that would just be a side effect, not the goal in itself.”
Theoretical physics has never shunned away from the seemingly impossible. To live forever, therefore, is a plausible scenario until the opposite has been proven. By escaping through a wormhole into another dimension, for example, we could reverse time – and cheat death.
One of the iron laws of physics is the Second law of thermodynamics, which says that everything most move from order to disorder; never the other way around. This principle is called entropy. For example, burning an old chair turns a functional and ‘ordered’ piece of matter into a chaotic and disordered cloud of ash and smoke. It’s straightforward to accelerate entropy by burning the chair, but it is (currently) impossible to reassemble the chair from the resultant ash and smoke.
The atoms of which we are made of too have to obey the Second law of thermodynamics. This causes us to age, and eventually, die. Theoretical physicist and author of Physics of the Future Michio Kaku believes there might be a way out of this- escaping through a wormhole: “Perhaps civilisations billions of years ahead of ours will harness enough energy to punch a hole in space and escape, in a hyper-dimensional space ark, to a new universe. Calculations show that these gigantic machines must be the size of star systems. Unfortunately, other calculations show that a wormhole might only be microscopic in size. If so, an advanced civilisation might resort to shooting molecular-sized robots, called “nanobots”, through the wormhole. These could carry the entire genetic database of the human race. Once on the other side, these nanobots would then create huge DNA factories to grow clones of their creators. Although the physical bodies of these individuals will have died, their genetic twins will live on.”
Nanobots to the rescue
Nanobots might not only be useful in the distant future, but also within a few decades. It is anticipated that they could be equipped with all sorts of tools and cameras in order to furnish more extensive information about the human body. And it doesn’t stop there. Researchers expect that someday refined nanobots will be developed, that are designed to the point where they can be remotely controlled in order to perform millions of useful tasks. Among these is the ability to float neutrally through your bloodstream, identifying problem areas of your body and fixing them. Furthermore, nanobots could be used to clear the built-up cholesterol from your arteries, thereby saving you from a heart attack. If the heart itself is damaged, they work their way up to the affected area and perform micro-surgery that you would probably not feel or notice. And most importantly, nanorobots’ ability to interact with materials in their most basic form may enable them to effectively rebuild or “regrow” damaged tissue.
Kaku too believes that certain medical developments of the future will enable us to drastically extend our lifespan. “In the future, all of us will have a CD-ROM with all of our genes on it,” he says. “It’ll cost about a hundred dollars. We’ll be able to scan the genes of old people by the millions, scan the genes of young people by the millions, and subtract. And when you subtract the genes of old people from young people, bingo, you have the genes that control the ageing process. We’ve already found 60 genes that control human ageing. So it’s conceivable now that maybe our grandkids will have the ability to reach the age of 30, and then they’ll simply stop. They’ll simply decide that, “Hey, I like being 30,” and they’ll cruise at age 30 for several decades.”
The human brain is one of the most complex systems in the universe. Figuring out how we get from cells and wires to thoughts and memories, is one of the greatest challenges known to science. Being able to crack the code might enable us to digitize our brains. That way, we could live forever inside a machine.
We are our brains
Neuroscientist Olaf Sporns, who works at Indiana University, has been studying the brain for quite some time. Sporns’ goal is to chart every single neurone and synapse, and create a complete map of the brain; ‘the connectome’. It’s a comprehensive set of connections that will allow us, for the first time, to understand in more detail how brain regions are connected to each other. Sporns is creating the connectome using a new technique called ‘diffusing imaging.’ It reveals the brain’s long distance connections by tracking water molecules along the neurological highways. What emerges is a detailed map of the central core of brain cells’ connections. Is this the area where awareness and consciousness, everything that makes us who we are, resides?
“As we’ve been discovering recently, some brain regions are more connected than others,” says Sporns. “Some are more essential for the functioning of the brain as a whole. Those regions we call hubs. By their nature, hubs are focal points of information traffic. Information converges on these regions, and it is that ebb and flow of information and the magnitude of that flow, that really sets these hubs apart from other regions of the brain.”
Finding that one part of the brain in which our ‘self’ is located is one of the most important quests of neuroscience. According to Sporns, the key might be the so-called precuneus, a region located in the medial area of the superior parietal cortex. “This area is very highly active in many cognitive tasks or mental states that involve self-reflection, thinking about the past and the future, retrieving memories,” Sporns explains. “It’s sort of part of a network that kicks into high gear when we’re not engaged in anything cognitively demanding in the outside world. It is part of a network that perhaps relates to ‘self’ processes.”
So suppose Sporns is right and our ‘self’ really is nothing more than a bunch of neurones and connections. How does that make us immortal? To achieve that goal, we would have to be able to copy our brain to a machine; also known as ‘mind uploading’. This hypothetical process requires the transferring of a conscious mind to a computer, by scanning and mapping a biological brain in detail and copying its state into a system. The computer would have to run a simulation model so faithful to the original, that it would behave in exactly the same way as the biological brain. To put it in other words: you would become a machine. And if the processes of the mind can be separated from the body, they are no longer tied to the limits and lifespan of that body.
Our ‘self’ really is nothing more than a bunch of neurones and connections
The idea isn’t new. In 1971, biogerontologist George Martin already outlined a hypothetical proposal for achieving ‘immortality’ through a process we now describe as mind uploading: “The ultimate solution [for immortality] is pure science fiction. […] We shall assume that developments in neurobiology, bioengineering and related disciplines… will ultimately provide suitable techniques of ‘read-out’ of the stored information from cryobiologically preserved brains into nth generation computers capable of vastly outdoing the dynamic patterning of operation of our cerebral neurones.” Olaf Sporns, however, is not sure mind uploading will grab the essence of life. “Just imagine all the things that happen in the real world, for example during a conversation. It includes hand gestures, speech sounds; our brains interact in an embodied manner. That could not happen in a computer. Yet, it is somehow the essence of what life’s all about. So I’m sceptical.”
Sporns’ scepticism is understandable. If we could reach a state of digital immortality, does this mean ‘we’ are still living? And isn’t the whole concept of living defined by the inevitability of dying? Whether we extend our lifespan by altering our DNA, getting rejuvenation therapy or by crawling through a wormhole, none of these options are available yet. In the mean time, we still have some time to decide whether it’s desirable to live forever. And that too, is what makes us human.