Throughout history humans have pursued the elusive prize of immortality. Kings, Alchemists, Scientists, all have tried and failed to reach this goal, various religions have offered eternal life as a reward, and although from this pursuit stems the discovery of many important medical advances, no-one has yet succeeded in eluding their demise.

However, now; in the year 2008 we are perhaps the closest we have ever been to realising, if not true immortality, life extension the likes of which have never before been possible. While there are numerous moral, social and economical arguments about life extension, none will be discussed in this article. What I will list in this article are five of the most probable advances in technology which offer us vastly extended, or even eternal lives (of a sort).

Cybernetic Immortality or ‘Mind Uploading’

The practice of ’scanning’ a human brain and recording its state at a given time onto a non-biological substrate is a concept that has been explored by many science fiction writers (notably William Gibson, Peter Hamilton and Ian M. Banks). Whilst this process might arguably fail to preserve a person’s consciousness or ’soul’, the concept of being able to store a copy of your brain to ‘download’ a new version of yourself could be considered a form of immortality.

While this process is not yet possible, scientists are continually making progress in the study of the human brain, and the production of computers that work more and more like their biological counterparts. Advances in our understanding of how signals travel and originate in the brain, how data is stored and organised as memories and novel methods of scanning human tissue are all making the possibility of creating a hard copy of someone’s consciousness and memories seem more and more real.

Chips have been made which can interface with the brain, or mimic parts of it; neuroscientist Ted Berger of the University of Southern California has produced a microchip (about a millimetre squared in size) which can translate signals from a rat’s brain into code it understands, and send signals back in a format the brain can use.

Whilst hardware like this has a long way to go, as does the understanding required to program these signals into useful forms, the progress is tantalizing. Berger predicts that the first human trials of this chip in treating Alzheimer’s patients are no more than 15 years away, which means that the first working brain implants could be coming within our lifetimes; indeed, if progress continues at this rate, a full copy of the brain might not be too fantastical an idea after all.

But whilst we’re busy replicating the brain, why stop there? Replacement eyes, ears, arms, legs and many other organs are in production as we speak. Artificial hearts are making great progress and an artificial bladder has been produced for the first time ever. This opens up the road for humans to gradually replace parts of themselves as they ‘break down’, effectively maintaining themselves as one would a car, or even upgrading parts as with a home pc. Nevertheless, the question remains; where does our humanity end? What do we become when we are more machine than man, and if we were to ultimately replace all our parts with superior artificial ones, could we still be considered human?

DNA Therapy and Genetic Engineering

If the body is a machine, DNA is both the schematic and the programming. Every aspect of our lives, from our weight to our happiness, our height, looks, strengths or weaknesses and even personalities are in some way influenced by our DNA. If we could change this schematic, rewrite the code, the possibility of extending and improving our capacity for life would be almost endless.

And science is gradually achieving just that ability. Already the human genome has been sequenced, and over 100 Gigabases (100,000,000,000 bases; the ‘letters’ of the genetic code) from various species including us have been documented and stored. Whilst we don’t yet know the specific function of most of these genes, they are gradually revealing their purposes to us.

Genes have been found which relate to weight gain or loss, inherited disease, physical characteristics, sexual orientation and even ageing. With this knowledge, scans of people’s genome could be made which allow personalised medical treatment and diets, and could explain many ailments for which we as of yet have no cure. Changes could be made to the genes which regulate our appetites to discourage overeating, and genes linked to ageing could be modified or replaced to allow us to live longer and repair ourselves more effectively. Genes from other species could be used in our bodies to code for desirable characteristics, and potentially damaging genes which code for inherited disease or malformation can be removed and repaired in the foetus.

Whilst this is all well and good, we’ve got a long way to go before any of this becomes a reality. Research is going on regarding the changing of an adult’s DNA (gene therapy), but progress is slow, whilst the editing of babies’ genes, producing ‘designer babies’ evokes a huge amount of controversy.

Nevertheless, progress is being made, and with every step forwards we come closer to the dream of being able to edit our bodies how we wish to suit our lifestyles and increase longevity. Viruses are being experimented with in the field of gene therapy, where they infect a body and insert or remove genes, and new genes coding for different characteristics are being found every day.

Stem Cell Research

The cells that make up our body invariably age, and die, and are replaced, until old age reduces our ability to replace dead cells to the extent that we cannot keep going, and our life ends.

But what if we could boost that repair system?

Stem cells are a type of cell found in both embryos and adults (though in differing forms). These cells are capable of renewing themselves via mitosis, and can differentiate into a wide range of mature cells, thereby allowing a foetus to develop, and an adult body to repair itself easily.

So what if these cells could be collected or even produced artificially, given to people whose own repair systems need a boost, and stimulated to grow into the cells the patient needs? Ageing could effectively be halted, as organs would not deteriorate and any dead cells could be replaced with fresh ones. Alternatively, these cells could be used to produce entire organs outside of the body, and these could be transplanted as and when a given organ fails. A form of stem cell therapy already exists for some conditions, notably bone marrow transplants for leukaemia patients (allowing the patients to produce new blood cells and immune cells over a long term when their own natural ability to do so has been damaged).

Whilst research into stem cells looks promising, controversy in the field has slowed progress dramatically, both in terms of production and use of the cells. Cells harvested from foetuses are argued to be morally wrong, and opponents of the research argue that embryonic stem cell technologies are a slippery slope to reproductive cloning and could devalue human life. Faked research has been published about the topic, particularly from Korean researcher Hwang Woo-Suk, who announced that he had produced embryonic stem cell lines from unfertilised human eggs; the lines were later shown to be fake.

The possibility of manipulating adult stem cells to act like their embryonic counterparts has, in principle, been demonstrated, but not enough progress has been made to remove the controversy surrounding usage of embryonic cells.

If stem cell research continues, tissue regeneration and age-prevention therapies look to be at least partly possible within our lifetimes.

Cryonics

Cryonics (not to be confused with cryogenics) is the low-temperature preservation of humans and other animals which current medicine cannot sustain, in the hopes that future techniques can be used to repair them.

This method of ‘life extension’ is already legal and practised in many places in the world (for example, in the USA, where the patient has to be legally deceased and the heart demonstrated to have stopped before preservation is permitted). The patient is pumped full of chemicals called ‘cryoprotectants’ which prevent damage from ice crystals and the preservation process, and then is cooled to around 77K (-196°C), preserving the body in the state it was in at the time of ‘death’.

Whilst dead in legal and conventional terms, and current cryopreservation methods are irreversible with current technology, the hope is that the patient can be resuscitated at some future point, and any damage from either the cause of death or the preservation process itself can be repaired.

Whilst cryopreservation offers an extension to life by making future technologies potentially accessible to the patient, it in itself does not extend life, rather it preserves the body as well as possible at the point of death.

Calorie Restriction

The lowering of energy intake, or calories, when practised in an otherwise healthy diet, has been demonstrated in laboratory experiments to extend the maximum lifespan of almost every species tested so far, including rats, yeast, fruit flies, and nematodes.

In rats, a roughly 50% decrease in calorie intake compared to an animal that freely fed led to an extension of lifespan by the same amount. Experiments on calorie restriction are now being carried out on primates, to see if the same will work with humans, and many scientists are confident that similar results will be seen.

Whilst the other technologies mentioned in this article are not yet scientifically possible, calorie restriction is possible now, for anyone who decides to practice it, and the potential benefits are massive,

Nevertheless, a high level of scepticism exists in the scientific community about the practice, as some scientists suggest that the practice only works in short-lived species which have evolved to respond to feast and famine with alterations in longevity.

Proving that the practice is generally applicable to most species is a challenge, but the results will certainly be seen far before any of the other technologies in this article. Along with calorie restriction, a healthy diet with the right levels of nutrients is perhaps the best form of life extension we have available at this point in time. Whilst this might sound trivial, it is only because of advances in nutritional science that we know what a ‘good diet’ is, and more progress is expected even here.