人类最长能活多久？
1978年11月14日，《纽约时报》开始刊出一个新的每周健康与科学栏目。四十年来，时报科学版提供了从气候变化到遗传再到引力波的各种报道。
In 2003, on the 25th anniversary of the section, reporters offered up their thoughts on the most pressing questions in science. Fifteen years later, the questions have changed. But we’re still curious.
2003年，时值科学版的25周年纪念，记者们提出了他们对最紧迫的科学问题的看法。十五年后，问题发生了变化。但我们仍然好奇。
—Michael Mason ——迈克尔·梅森(Michael Mason)
The most common risk factor for serious disease is old age. Heart disease, cancer, stroke, neurological conditions, diabetes — all increase radically with advancing years. And the older a person is, the more likely he or she is to have multiple chronic illnesses.
严重疾病最常见的风险因素是高龄。心脏病、癌症、中风、神经系统疾病、糖尿病的风险都随着年龄增长而急剧增加。一个人年龄越大，他/她就越有可能患上多种慢性疾病。
Some scientists hope one day to treat all of them at once — by targeting aging itself. 有些科学家希望有一天能够同时治疗所有这些疾病——通过针对衰老本身。
Humans aren’t built to last forever. The oldest person on record was Jeanne Calment, a Frenchwoman, who died in 1997 at the age of 122. In 2040, the average life span for people in Spain, projected to pass Japan as the country with the longest-lived citizens, will reach about 86 years.
人类不是永生的。有史以来最长寿的人是法国女性让娜·卡尔芒(Jeanne Calment)，她于1997年去世，享年122岁。2040年，西班牙人的平均寿命预计将超过日本，成为拥有最长寿公民的国家，人均寿命将达到约86岁。
There is considerable dispute, however, over how long humans might live under optimal circumstances. In 2016, a team of scientists declared the upper limit to be 115 years. But in June, researchers reviewing death rates among elderly Italians suggested that there may be no limit at all.
然而，人类能在最理想的环境下活多久的问题有相当大的争议。2016年，一组科学家宣布上限应为115岁。但在6月，查看意大利老年人死亡率的研究人员表明，人类寿命可能根本没有任何限制。
In animal studies over the last few decades, scientists have begun to understand the specific cellular and molecular processes that cause the deteriorations of old age.
在过去几十年的动物研究中，科学家已经开始了解导致老年人身体退化的特定细胞和分子过程。
In an essay in the journal JAMA last month, Tamara Tchkonia and Dr. James L. Kirkland of the Mayo Clinic categorized these processes into four broad groups: chronic inflammation; cell dysfunction; changes in stem cells that make them fail to regenerate tissue; and cellular senescence, the accumulation in tissue of aging cells that accompanies disease.
上个月在《美国医学会杂志》(JAMA)上发表的一篇论文中，梅奥医院(Mayo Clinic)的塔玛拉·奇科尼亚(Tamara Tchkonia)和詹姆斯·L·柯克兰(James L. Kirkland)博士将这些过程分为四大类：慢性炎症;细胞功能障碍;干细胞变化使它们无法再生组织;细胞衰老，及与疾病相伴的衰老细胞在组织中积累。
Old cells, researchers have found, secrete proteins, lipids and other substances that increase inflammation and tissue destruction. In one study in mice, researchers showed that transplanting these cells to the knee joints of healthy animals causes disease that looks very much like human osteoarthritis.
研究人员发现，衰老细胞分泌蛋白质、脂质和其他增加炎症和组织破坏的物质。在一项针对小鼠的研究中，研究人员显示，将这些细胞移植到健康动物的膝关节会导致看起来非常像人类骨关节炎的疾病。
Healthy young people have few of these aging cells, but after age 60, they begin to accumulate, and their increasing quantity correlates with disabilities of old age.
健康的年轻人很少有这样的细胞，但是在60岁以后，它们开始累积，并且其数量增加与老年失能相关。
Could there be any remedy that removes these old cells while leaving young cells? Several are being tested.
是否有什么治疗方法可以在留下年轻细胞的同时清除这些衰老细胞?有几项方法正在测试中。
In one study of mice, old cells have been found susceptible to a combination of two drugs: dasatinib, a cancer drug, and quercetin, a plant flavonoid. They improved cardiac function and exercise capacity in old mice, delayed symptoms of osteoporosis and prolonged healthy old age.
在一项针对小鼠的研究中发现，衰老细胞对两种药物的组合敏感：达沙替尼(一种抗癌药物)和槲皮素(一种植物类黄酮)。他们改善了老鼠的心脏功能和运动能力，延缓了骨质疏松的症状，并延长了健康的老年状态。
Some drugs already approved for other purposes are being tested as “senolytics,” as the drugs that kill old cells are now called.
一些已被批准用于其他目的的药物，正在测试作为抗衰老药(senolytics)的效力——这是目前能杀死衰老细胞的药物的通称。
Dr. Nir Barzilai, a professor of medicine at the Albert Einstein School of Medicine, is planning a study of metformin, a drug that has been used for 60 years to treat diabetes and has been shown to be effective against several age-related diseases.
阿尔伯特·爱因斯坦医学院(Albert Einstein School of Medicine)医学教授尼尔·巴兹莱(Nir Barzilai)博士正计划对二甲双胍进行一项研究，二甲双胍被用于治疗糖尿病已有60年的历史，并已被证明可有效对抗几种与年龄相关的疾病.
If drugs can treat aging, is aging itself a disease? No, Dr. Barzilai said. 如果药物能治疗衰老，衰老本身是一种疾病吗?不是，巴兹莱说。
“Neither I nor the Food and Drug Administration is interested in calling aging a disease. Our study is to show that we can prevent a composite of age-related diseases — cardiovascular, cancer, cognitive — and ultimately affect mortality.”
“我和美国食品和药物管理局(Food and Drug Administration)都无意称衰老为一种疾病。我们的研究表明，我们可以预防一系列与年龄相关的疾病——心血管疾病、癌症和认知疾病——并最终影响死亡率。”
Another drug candidate involves a coenzyme called nicotinamide adenine dinucleotide, or N.A.D. It functions in cell respiration, moving electrons into the mitochondria where energy is produced.
另一种候选药物涉及一种名为烟酰胺腺嘌呤二核苷酸或NAD的辅酶。它在细胞呼吸过程中起作用，将电子移动到产生能量的线粒体中。
As people age, levels of N.A.D. decline to the point where it is undetectable in the blood of the elderly.
随着人们年龄的增长，NAD的水平下降到在老年人血液中无法检测到的程度。
David A. Sinclair, a professor of genetics at Harvard, is working on methods of replenishing those levels. In studies of yeast, worms, flies and mice, “that replenishing rapidly reverses some aspects of aging,” he said. “And now there are trials underway in humans.”(N.A.D. is already peddled in health food stores, but scientists like Dr. Barzilai say it’s a bad idea to take a nutraceutical to extend life — or even an established medication like metformin — until the clinical data are in.)
哈佛大学(Harvard)遗传学教授大卫·A·辛克莱(David A. Sinclair)正在研究补充这种物质水平的办法。在针对酵母菌、蠕虫、苍蝇和小鼠的研究中，“补充NAD能快速逆转衰老的某些方面，”他说。“而现在正在进行人类试验。”(NAD已经在健康食品商店里售卖，但像巴兹莱这样的科学家说，在得到临床数据之前，服用营养食品延长生命——甚至是二甲双胍等早已投入使用的药物——是一个坏主意。)
One widely published researcher in the field, S. Jay Olshansky, a professor of epidemiology at the University of Illinois at Chicago, said that there is an upper limit to how long we can live — about 85 years.
伊利诺伊大学芝加哥分校(University of Illinois at Chicago)流行病学教授S.杰伊·奥尔沙恩斯基(S. Jay Olshansky)是在该领域发表了诸多论文的研究者，他说我们能活多久有一个上限——大约85年。
“Parts of the body, including the brain, are not designed for long-term use,” he said. “We’re seeing the consequences of pushing the limits of survival: the rise of Alzheimer’s disease, dementias, joint and hip problems, loss of muscle mass.”
“身体的某些部位，包括大脑，不是为了长期使用而设计的，”他说。“我们正在看到推动生存极限的后果：阿尔茨海默病、失智症、关节和髋关节问题的增加、肌肉质量的减少。”
“These are not a consequence of failure, but of success,” he added. Dr. Olshansky advocates extending “health span, not life span.”
“这些不是失败的结果，而是成功的结果，”他补充道。奥尔沙恩斯基主张延长“健康跨度，而非生命跨度”。
We will all die. No serious scientist believes in immortality. But we also are closer to assuring healthier old age than ever before.
我们都会死。严肃的科学家是不相信永生的。但与此同时，我们距离有保障的健康晚年也更近了一步。
“There are dozens of companies in clinical trials, or planning them, tackling all the different causes of aging,” Dr. Sinclair said. “I’m optimistic that there will be a few successes in the coming years.”
“有许多公司正在进行或计划临床试验，阻断所有不同的衰老原因，”辛克莱说。“我很乐观，未来几年会取得一些成功。”
