On November 14, 1978, the New York times began a new weekly health and science section. For four decades, The Times science section has provided coverage of everything from climate change to genetics to gravitational waves.
In 2003, the 25th anniversary of the science edition, journalists presented their views on the most pressing scientific issues. Fifteen years later, the problem has changed. But we're still curious.
-- Michael Mason
The most common risk factor for serious illness is advanced age. The risk of heart disease, cancer, stroke, neurological disease, and diabetes all increase dramatically with age. The older a person is, the more likely he or she is to develop a variety of chronic diseases.
Some scientists hope to one day treat all these diseases at once -- by targeting aging itself.
Man is not immortal. The oldest person ever was Jeanne Calment, a French woman who died in 1997 at the age of 122. By 2040, spaniards are expected to outlive Japan as the country with the oldest citizens, with an average life expectancy of about 86 years.
However, there is considerable debate about how long humans can live under optimal conditions. In 2016, a team of scientists announced that the upper limit should be 115. But in June, researchers looking at mortality rates among the elderly in Italy suggested that there may be no limit to human longevity at all.
In animal studies over the past few decades, scientists have begun to understand the specific cellular and molecular processes that cause degeneration in the elderly.
In a paper published last month in JAMA, Dr. Tamara Tchkonia and James l. Kirkland of the Mayo Clinic broke down these processes into four broad categories: chronic inflammation; Cellular dysfunction; Stem cell changes make it impossible for them to regenerate tissue; Cell senescence, and the accumulation of senescent cells in tissues associated with 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。
The researchers found that senescent cells secrete proteins, lipids and other substances that increase inflammation and tissue destruction. In a study of mice, researchers showed that transplanting these cells into the knee joints of healthy animals caused a disease that looked very much like human osteoarthritis.
Healthy young people rarely have such cells, but after the age of 60 they start to accumulate, and their number increases associated with disability in old age.
Is there any treatment that can clear these senescent cells while leaving the younger ones? Several methods are being tested.
In a study of mice, senescent cells were found to be sensitive to a combination of two drugs: dasatinib, an anticancer drug, and quercetin, an plant-based flavonoid. They improved heart function and exercise, delayed the onset of osteoporosis, and prolonged healthy old age.
Some drugs that have been approved for other purposes are being tested as senolytics, the current generic term for drugs that kill aging cells.
Dr. Nir Barzilai, a professor of Medicine at Albert Einstein School of Medicine, is planning a study on metformin, which has been used to treat diabetes for 60 years 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, said barzilai.
Neither I nor the Food and Drug Administration have the intention of calling aging a disease. Our research shows that we can prevent a range of age-related diseases -- cardiovascular, cancer and 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 candidate involves a coenzyme called nicotinamide adenine dinucleotide, or NAD. It plays a role in cellular respiration, moving electrons into energy-producing mitochondria.
As people age, NAD levels drop to levels undetectable in the blood of older people.
David a. Sinclair, A professor of genetics at Harvard, is studying ways to supplement those levels. In studies on yeast, worms, flies and mice, "supplementing NAD can quickly reverse some aspects of aging," he said. "And now it's being tested on humans." (NAD is already sold in health food stores, but scientists like barzilai say it's a bad idea to take nutritious foods to prolong life -- even long-used drugs like metformin -- until clinical data are available.)
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。)
S. Jay Olshansky, a professor of epidemiology at the University of Illinois at Chicago and a researcher who has published several papers in the field, said 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 are seeing the consequences of pushing the limits of survival: alzheimer's disease, dementia, increased joint and hip problems, decreased muscle mass."
These are not the results of failure, they are the results of success, he added. Olshansky advocates extending "health span, not life span."
We all die. Serious scientists don't believe in immortality. But at the same time, we are one step closer to a secure and healthy old age.
There are many companies that are conducting or planning clinical trials to block all the different causes of aging, Sinclair said. "I am optimistic that there will be some success in the next few years."