Most of us think we know what aging is like. It is advertised with wrinkled skin and gray and thinning hair. It blurs the vision, makes the joints creaky and, if not strictly combated, makes things break down.
But scientists are cataloging much more subtle signs of biological aging, evident long before hair and skin loss begins to wrinkle.
19:33, January 18, 2020
This story incorrectly described Judith Campisi as a biochemist at USC. It is based at the Buck Institute for Aging Research in Novato, California, which is not part of USC.
It is a story told not only in the body's organs, but in its genes, cells and proteins – even in the bacteria that colonize us. First, one or two molecular processes are out of control. These flaws send out broader functions. Sometimes, all at once, sometimes gradually, our organs suffer and entire networks – the immune system, for example – start to falter.
Understanding how it all happens can allow us to live another day. But a closer goal can produce an even greater return: defining what aging is and exactly how it progresses can allow us to stay healthy for more of our lives.
Two new researches bring this objective to extend the "health" of human beings a little closer. Both identify biomarkers that help define what it means, at a microscopic level, to age. Both focus on the mechanisms that tend to break down as we age – in other words, targets of therapies that can interrupt or delay the aging process.
And both offer some guidelines for measuring the effectiveness of elixirs that promise to be (but rarely are) fountains of youth.
In one of the new studies, Stanford University researchers combed 18 million data points collected from 106 people who were monitored for two to four years. The goal was to detect patterns common to everyone as we age, as well as patterns that vary from person to person.
Emerging from that study, published this week in the journal Nature Medicine, is the idea that individuals age over at least four biological “pathways”. While one person may be more likely to decline in kidney function, another may experience the greatest age-related degradation in the liver, immune system or metabolic function, the results suggest.
Most of us are likely to age on some or all of these fronts, if not more, said the Stanford geneticist Michael Snyder, who led the research. But classifying people by their personal “aging style,” or areas of greatest vulnerability, can help them identify and prevent their most likely depredations of aging, he said.
In the second study, scientists at USC & # 39; s Buck Institute for Aging Research profiled the known universe of tissues and cells that can reveal the biological age of the human body. Used the data collected as part of a study that followed 3,200 volunteers throughout their adult lives since 1958.
The atlas of aging biomarkers will accelerate efforts to find and develop drugs that can slow biological aging, said the USC biochemist Judith Campisi, who led the work published this week in the journal PLOS Biology. One day, she added, it could allow doctors to provide patients "with a clear reading of how well or badly their various tissues and organs are aging."
After centuries of snake oil and hucksterism, the fight against aging has become real in recent years. Scientists focused on "senescent" cells, which stop dividing under stress, as a key factor in diseases like cancer, heart disease, diabetes, arthritis and dementia. Because these diseases are more common as we age, they and their root causes have become central to scientists' understanding of aging.
Researchers are increasingly suspecting that when you stop the development of one aging disease, it can help protect against others – a principle called the "unitary theory of fundamental aging processes". If, for example, senescent cells and the inflammation they cause could be brought under control, perhaps many age-related diseases – in fact, unhealthy aging itself – could be prevented and the experience of aging could be much less unhappy.
This is the idea behind the search for "senolytics" – drugs or therapies that can remove or stop senescent cells. If such anti-aging drugs are developed and used safely, researchers will need to recognize the many forms that senescent cells take and measure what happens when different members of that group are removed or suppressed.
In the Stanford University study, the researchers sequenced genes; analyzed blood, urine and saliva samples; and probed the microbes in the entrails and noses of 43 people. The team found 608 molecules that could be evaluated and used to identify likely contributors to age-related problems.
The Stanford team created four "age types" based on these biomarkers and how they changed over time. Although the list is likely to expand with more research, the authors suggest that people tend to age more along one of four distinct biological pathways: metabolic, immune, hepatic (or hepatic) and nephrotic (or renal).
A person whose dominant age type is metabolic can see it A1C, a measure of blood sugar levels, increases with age, potentially leading to type 2 diabetes. A person with an immune age, on the other hand, may experience increased inflammation throughout the body, making him more vulnerable to a heart attack and certain types of cancer.
The work is highly preliminary. Dr. Zoltan Arany who studies aging processes at the University of Pennsylvania Perelman School of Medicine, said that while investigating a wide range of measures and looking for changes over time, determining whether they really cause aging or are innocent people in the process "will take a lot more work. "
Even after scientists have established the common roots of age-related illnesses – a task that is far from complete – there is still a lot of work ahead, he said. Dr. James L. Kirkland, who studies aging at the Mayo Clinic. If studies like the two published this week help humans to age better, they will have to explain why we age so differently and predict which of the many routes each of us will follow.
"Right now, we're measuring everything," said Kirkpatrick. "But the effort will be to decrease, to obtain a score composed of biomarkers, which is predictive of a future decline in the level of health."
Snyder said he shared that long-term goal.
"I can imagine a world in which everyone measures your age type, so that, with the slightest sign of acceleration, you can intervene," he said. For some, this may be taking a statin to lower cholesterol, and for others, it may mean exercising more.
"It can get you started in the ass" to deal with these vulnerabilities, he said.