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更新时间:2018/11/21 19:39:44 来源:纽约时报中文网 作者:佚名

How Long Can People Live?

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.


Some scientists hope one day to treat all of them at once — by targeting aging itself.


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.


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.


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.


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.


Could there be any remedy that removes these old cells while leaving young cells? Several are being tested.


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.


Some drugs already approved for other purposes are being tested as “senolytics,” as the drugs that kill old cells are now called.


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.


“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.


As people age, levels of N.A.D. decline to the point where it is undetectable in the blood of the elderly.


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.”


“These are not a consequence of failure, but of success,” he added. Dr. Olshansky advocates extending “health span, not life span.”


We will all die. No serious scientist believes in immortality. But we also are closer to assuring healthier old age than ever before.


“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.”