An anti-aging drug may not be an impossible dream

 Longer and healthier lives may be possible with new perspectives on the biology of senescence.

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Since the early 1800s, the best-performing nations' life expectancies have been rising by three months annually. Due primarily to mortality from infectious diseases and accidents, you had an approximately 50/50 chance of living into your twenties over the majority of human history. The end result is undoubtedly humanity's greatest accomplishment—we've literally doubled what it means to be human, raising lifespans from 40 to 80 years—thanks to progressive discoveries of techniques to prevent and treat such causes of death. On the other side, this has enabled one scourge to surpass all others and emerge as the leading cause of death worldwide: aging.

Over two-thirds of deaths now around the world—more than 100,000 individuals each day—are caused by aging. This is due to the fact that, despite what it may seem like, the aging process itself is the main risk factor for the majority of the leading killers in the modern world: As we age, cancer, heart disease, dementia, and many other health issues become significantly more prevalent. While it is common knowledge that variables like smoking, inactivity, and a poor diet can raise the risk of chronic diseases, these are very insignificant in comparison to aging. For example, having high blood pressure doubles your risk of suffering from a heart attack, and being 80 years old as opposed to 40 years old increases your risk by ten.The amount of mortality and misery brought on by aging will only grow as the world's population ages.

But I don't foresee this since, aside from being dismal, extending a two-century tendency for another year is hardly novel. The possibility of the first medication that specifically tackles the biology of aging in 2023 is far more intriguing.

Biologically speaking, scientists currently have a decent understanding of what makes humans age: The so-called "hallmarks" of aging include everything from damage to our DNA, which serves as each cell's instruction manual, to proteins that perform improperly as a result of structural changes to their chemical makeup. The most exciting part is that we now know how to treat them.

It's likely that one of these concepts will be proven to operate in humans by the end of 2023. The term "senolytics" refers to a family of medications that targets old cells, or "senescent cells," which build up in our bodies as we age. The removal of these cells appears to slow down the aging process and may even reverse it. These cells appear to promote the aging process, causing malignancies and neurodegeneration.

In studies where mice were given a senolytic cocktail of dasatinib (a cancer drug) and quercetin (a molecule found in colorful fruit and veg), not only did they live longer, but they were also less frail (they could run further and faster on the tiny mouse-sized treadmills used in the experiments), had thicker, glossier fur, and were at lower risk of diseases like cancer.

More than two dozen businesses are exploring for secure, practical methods to eliminate these senescent cells in people. The largest is Unity Biotechnology, which is testing a variety of senolytic medications against diseases like macular degeneration (a cause of blindness) and lung fibrosis. It was formed by the Mayo Clinic researchers that conducted the mice experiment and has investors that include Jeff Bezos. Numerous strategies are being researched, including gene therapy by a company called Oisn Biotechnologies, which takes its name from an Irish mythological figure who journeys to Tir na ng, the land of eternal youth. These strategies include small proteins that target senescent cells, vaccines to encourage the immune system to clear them out, and even vaccines that target senescent cells.

Senolytics aren't the only potential candidates, though: Others that are now being tested on people include the protein GAIM from Proclara Biosciences, which removes sticky "amyloid" proteins, and the gene therapy from Verve Therapeutics, which lowers cholesterol by changing the PCSK9 gene. Instead of treating aging as a whole, the first effective anti-aging drug will likely focus on a single age-related disease caused by a particular characteristic. But in the not-too-distant future, we'll be able to think about this loftier objective thanks to the success of a medicine that combats an aspect of aging in clinical trials.

Early success of these medicines in 2023 may serve as the impetus for the biggest medical revolution since the discovery of antibiotics. We'll intervene preventively to stop people from becoming ill in the first place—and, if those treadmill-shredding mice are anything to go by, we'll reduce frailty and other problems that don't always elicit a medical diagnosis at the same time. This will avoid treating age-related problems like cancer and dementia in their late stages when they're very difficult to fix.