Want to live longer? For centuries the attempt to stop ageing was the preserve of charlatans touting the benefits of mercury and arsenic, or assortments of herbs and pills, often to disastrous effect. Yet after years of false starts, the idea of a genuine elixir of longevity is taking wing. Behind it is a coterie of fascinated and ambitious scientists and enthusiastic and self-interested billionaires. Increasingly, they are being joined by ordinary folk who have come to think that the right behaviour and drugs could add years, maybe decades, to their lives.

想活得更久？几个世纪以来，企图长生不老一直是江湖骗子的专利，他们兜售汞、砷、各种草药、药丸的好处，往往会带来灾难性的后果。然而，在经历多年的失败尝试后，研制真正长生不老药的构想已经开始了，推动这一构想的是一群心驰神往、雄心壮志的科学家，充满热情、出于私利的亿万富翁。越来越多的普通人也加入了这一行列，他们意识到合理的生活习惯和药物可以让他们多活几年，甚至几十年。

Living to 100 today is not unheard of, but is still rare. In America and Britain centenarians make up around 0.03% of the population. Should the latest efforts to prolong life reach their potential, living to see your 100th birthday could become the norm; making it to 120 could become a perfectly reasonable aspiration.

当今活到100岁并非闻所未闻，但还是罕见。在美国和英国，百岁老人约占人口的0.03%。如果延长寿命的最新努力发挥了潜力，活到100岁生日可能会成为常态，活到120岁可能成为完全合理的愿望。

More exciting still, those extra years would be healthy. What progress has been made in expanding lifespans has so far come by countering the causes of death, especially infectious disease. The process of ageing itself, with its attendant ills such as dementia, has not yet been slowed. This time, that is the intention.

更令人振奋的是，延长的寿命将是健康的。迄今为止，人类在延长寿命方面取得的进展是通过对抗死亡因素来实现的，尤其是传染病。衰老的过程及其伴随的痴呆症等疾病并未得到减缓，这次的研究方向就在于此。

The idea, as we set out in our Technology Quarterly, is to manipulate biological processes associated with ageing that, when dampened in laboratory animals, seem to extend their lives. Some of these are familiar, such as severely restricting the number of calories an animal consumes as part of an otherwise balanced diet. Living such a calorie-restricted life is too much to ask of most people; but drugs that affect the relevant biological pathways appear to bring similar results. One is metformin, which has been approved for use against type-2 diabetes; another is rapamycin, an immunosuppressant used in organ transplants. Early adopters are starting to take these drugs “off label”, off their own bat or by signing what amount to servicing contracts with a new class of longevity firms.

正如我们在《科技季刊》中所阐述的那样，这个构想是控制与衰老相关的生物过程，如果实验动物被抑制这些生物过程，似乎可以延长它们的寿命。某些生物过程是我们熟知的，例如在平衡饮食的基础上严格限制动物摄入的热量。对于大多数人来说，这种热量限制的生活太难了；但影响相关生物通路的药物似乎也能产生类似的效果。其中一种是二甲双胍，已被批准用于治疗2型糖尿病；另一种是雷帕霉素，用于器官移植的免疫抑制剂。早期服用者开始“超说明书”用药，他们自行服用，或者与一种新型的长寿公司签订服务合同。

Another path is to develop drugs that kill “senescent” cells for which the body has no further use. The natural means for disposing of these cells, like a number of other repair mechanisms, themselves weaken with age. Giving them a helping hand is not just a matter of tidying up. Senescent cells cause all sorts of malfunctions in their healthy neighbours. “Senolytic” drugs which target them pose obvious risks: it is hard to kill off one type of cell without inconveniencing others. But the promise is clear.

另一种方法是研制药物，消灭人体不再需要的“衰老”细胞。就像许多其他修复机制一样，处理掉衰老细胞的自然方法是随着年龄的增长而变弱。帮它们一把不只是清理的问题，衰老细胞会导致健康细胞的各种功能失调。针对它们的“抗衰老”药物存在显著的风险：很难消灭一种细胞而不损害其他细胞，但显然是有希望的。

For true believers that is just the beginning. Groups of academic and commercial researchers are studying how to rejuvenate cells and tissues by changing the “epigenetic” markers on chromosomes, which tell cells which genes they should activate. These markers accumulate with age; strip them back and you might produce the cells of a 20-year-old body inside one that is in fact 65. Mimicking calorie restriction and clearing out senescent cells would delay ageing. Boosters claim that epigenetic rejuvenation could halt or reverse it.

对于真诚的信徒来说，这只是个开始。多个学术和商业研究团队正在研究如何通过改变染色体上的“表观遗传”标记来恢复细胞和组织的活力，这些标记告诉细胞应该激活哪些基因。这些标记随着年龄的增长而不断积累；减少这些标记，65岁的身体可以产生20岁的细胞。模拟热量限制和清除衰老细胞能够延缓衰老。支持者声称，表观遗传再青春化可以阻止甚至逆转衰老。

One cause for concern is people’s brains. Slowing bodily ageing will not change the fact that the brain has a finite capacity, and is presumably adapted by natural sextion to conventional lifespans. This is quite separate from worries about dementia, which is caused by specific diseases. Society will thus have to find ways to adapt to the normal ageing in brains: centenarians may, for instance, find themselves increasingly occupied with asking their ai diary assistants questions for which once they would have remembered the answer.

令人担忧的问题是人的大脑。减缓身体的衰老并不能改变大脑容量有限的事实，而且大脑可能已经通过自然选择适应了常规寿命。这与对痴呆症的担忧完全不同，痴呆症是由特定疾病引起的。因此，社会将不得不想办法适应大脑的正常衰老：例如百岁老人可能会越来越频繁地询问AI日记助手，他们曾经是记得答案的。

An even greater concern is that none of these ideas has yet been tested formally on people. That is partly because drug-approval agencies do not yet recognise old age as a treatable condition, making trials hard to register. By their very nature, such trials must follow thousands of people over many years, adding to their cost and complexity. The lack of testing is also partly because many of the initial proposals use out-of-patent molecules that are of little interest to drug companies. Nevertheless some trials are now in the works. The Targeting Ageing with Metformin trial (tame) will follow 3,000 Americans in their 60s and 70s to see whether the drug does in fact aid survival overall. Such studies will necessarily take time. But more of them are needed, and governments should be helping bring them about.

更令人担忧的是，这些构想尚未进行过正式的人体试验。部分原因是药物审批机构尚未意识到衰老是可治疗的疾病，所以人体试验很难注册。就其性质而言，这种试验必须对数千人进行多年的随访，这增加了试验成本和复杂性。缺少试验的另一个原因是，许多初步方案使用制药公司不感兴趣的非专利分子。尽管如此，一些试验正在进行中。二甲双胍抗衰老试验（TAME）将对3000名六七十岁的美国人进行随访，以观察该药物是否真的有助于提高整体生存率。这种研究固然需要时间，但需要进行更多的研究，政府应该帮助开展这种研究。

Any development that causes people to live healthily for longer, and to take fuller advantage of what the world has to offer, is cause for cheer. Some people, observing billionaires’ interest in longevity-promoting startups, worry that the benefits will be captured mainly by the rich, leading to a class of long-lived Übermenschen lording it over short-lived ordinary folk. But technologies have a record of spreading, and cheapening as they do so. It is hard to imagine a privilege more likely to spark rebellion than a ruling class that hoards age-treatments to escape the great leveller.

只要让人们健康长寿，并且更充分地利用世界提供的资源，这种发展都是可喜的。有人注意到亿万富翁对延寿的初创公司感兴趣，他们担心延寿的主要受益者将是有钱人，结果产生一个长寿的“超人”阶层凌驾于短命的普通人之上。但是，技术有普及和成本下降的特点。如果统治阶级秘藏抗衰疗法来逃避凡人皆要面对的死亡，恐怕没有比这更容易引发反抗的特权了。

The fact of many people living much longer would have wide ramifications. Most obviously, working lives will be extended, as they have already as life expectancies have lengthened, and possibly even more so for women, who will lose less of their careers to having children, perhaps narrowing inequality in the workplace. Over time there could be deeper shifts. People who live longer may care more about threats that are further away, such as the state of the world in 2100. Longevity permits the patient accumulation of capital, a factor in the emergence of a middle class. And times when political power is exercised mainly by young men, such as the Middle Ages in Europe, tend to be more violent than when older, cooler heads prevail. Families will span even more generations and, presumably, larger networks of exes, half-siblings and quarter-cousins. Will that atomise them, or bring them together? Will a surfeit of centenarians marginalise the young, create a cult of youth—or both?

许多人的寿命大大延长将会产生广泛的影响。最明显的是工作生涯将会延长，现在工作生涯已经随着预期寿命而延长了，女性可能更是如此，她们牺牲给生儿育女的工作生涯将会减少，可能缩小职场中的不平等。随着时间的推移，可能会有更深层次的变化。长寿的人可能会更关心长远的威胁，比如2100年的世界状况。长寿使人有足够的时间去积累资本，这是中产阶级兴起的一个因素。在政治权力主要由年轻人掌控的时代，比如中世纪的欧洲，往往比头脑冷静的老年人掌权的时代更加暴力。家族将会跨越更多世代，由此可能形成更大的家族网，涵盖前配偶、同父异母或同母异父的兄弟姐妹、四分之一堂表兄弟姐妹。这会使彼此的关系疏远还是团结？过多的百岁老人会让年轻人边缘化？成为崇拜对象？还是两种情况都会出现？

Forever and a day

直到永远

People will seize on the elixir of life if it becomes available. Natural sextion has no interest in indefinite longevity per se: the traits that spread best are those that make organisms fit in their prime; those that help them live on when reproduction is a distant memory must work through children and grandchildren. Yet the visceral drive to cling to life is the most basic trait of all. Indeed, it is prevailing today—to tantalising effect.

如果有长生不老药，人们就不会放过。自然选择本身对长生不老没兴趣：最容易传播的是使生物在鼎盛时期适应环境的特质；当繁殖成为久远的记忆时，有助于生物延续的特质一定会在子孙后代身上表现出来，但其中最基本的特质是本能的求生欲。确实，求生欲在今天仍然盛行，并且产生了诱人的效果。