In 2006 I was the convenor of a major conference organised by my Institute in Oxford. Called Tomorrow’s People, its aim was to consider - from scientific, social and ethical perspectives - radical attempts to enhance human capacities and lifespan.  The book of the conference was published in 2009[i]. The gerontologists at the conference fell into two camps - Aubrey de Grey and everybody else. Everybody else saw ageing as a process arising from the complex interplay of multiple biological and environmental factors involving accumulating cell damage, all of which which had to be understood and tackled in a cumulative, incremental scientific programme whose immediate objective might be to achieve an additional span of healthy life of about 7 years.  Aubrey de Grey – a slight man, informally dressed with a spectacular beard which makes him look something like an old testament prophet - agreed with the causes but not the treatment.  For him the perspective was that of an engineer:  accumulating cell damage was effectively ageing, and ageing could be halted or reversed by removing or repairing the damaged cells. He called his approach ‘Strategies for Engineered Negligible Senescence’, or SENS. The SENS approach identified seven main types of cell damage, which, when effectively countered, de Grey believed, would not only stop but reverse ageing and eventually allow people to live to the age when the length of life would effectively be limited only by the chances of death by accident or homicide – about 1000 years. To dramatise his point he said that the first person to live to 1000 had already been born. In describing the reactions of the ageing research community in his piece in the conference book de Grey quoted Gandhi’s aphorism:  first they ignore you, then they laugh at you, then they oppose you; finally they say that you are right and that they supported you all along.  In 2005 when we were trying to get a full range of opinion involved in our conference the matter was certainly at the second to third of these stages.  Provoked by an article from de Grey suggesting that the research community should get behind SENS because of the opportunity to save thousands of lives, 27 leading research scientists signed a journal article entitled ‘Science fact and the SENS agenda: What can we reasonably expect from ageing research?’ [ii] De Grey responded in the same issue and the two camps were entrenched - persuaded to share a platform at the Oxford meeting but only just. De Grey continued to pursue his path, but wisely developed a broad definition of SENS when recruiting to annual SENS conferences he organised, and benefiting from the rapid development of parallel streams of innovative science in tissue engineering and other approaches to what has become known as regenerative medicine. On 2 November 2011 Nature published online an article online entitled ‘Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders’ by a team of eight scientists associated with the Mayo Clinic College of Medicine in the US and Groningen University in the Netherlands.[iii] This type of senescent cell causes age-related pathologies to the eye, to sub-cutaneous fat and to skeletal muscle.  When removed for life from the bodies of the mice the experiment studies, these disorders were delayed in appearing or their further development was stopped.  The authors conclude that their data ‘indicate that cellular senescence is causally implicated in generating age-related phenotypes and that removal of senescent cells can prevent or delay tissue dysfunction and extend healthspan.’  In other words, the experiment provided proof of concept for the SENS approach. At the 2006 conference Aubrey de Grey said that the implications of these radical life technologies would hit the public in about ten years.  After the publication of the recent Nature article I sent him a note of congratulation and said that it appeared that five years after the Oxford conference his timetable seemed to be well on track. He modestly replied that there was still a long way to go.   However, now that we are halfway to somewhere very significantly different from where we have been on lifespan and ageing it may be time to work on the range of possible social, economic and ethical implications with a new sense of urgency.

[i] Peter Healey and Steve Rayner, eds., (2009)  Unnatural Selection: the Challenges of Engineering Tomorrow’s People.  Earthscan: London & Stirling, VA [ii] Warner, H., et al. (2005) Science fact and the SENS agenda: What can we reasonably expect from ageing research?’ EMBO Reports, 6, 11, pp 1006-1008 [iii] Darren J. Baker et al. (2011) Nature doi:10.1038/nature10600 Received 08 May 2011 Accepted 30 September 2011 Published online 02 November 2011