How We Age—and How Scientists Are Working to Turn Back the Clock
Scientists obsessed with aging are sketching a road map of how our bodies change as we grow old in the hopes that it will lead to treatments that could help us live longer, healthier lives.
They call this road map the “hallmarks of aging”—a set of biological features and mechanisms linked to our inexorable march toward death. Over the past decade, the hallmarks have helped guide the development of drugs that clear away cells that have stopped dividing and gene therapies that appear to restore cells to a more youthful state.
Scientists in Europe codified nine hallmarks in a 2013 paper in the journal Cell that is widely cited in the aging field. They include: shortening of telomeres (DNA segments at the ends of chromosomes); cell senescence, when cells stop dividing; and breakdowns in how cells regulate nutrients.
The hallmarks appear to manifest with age and accelerate aging when enhanced. They are interconnected in ways researchers are trying to understand. Some believe this could unlock insights into why we age.
Scientists are getting closer to solving mysteries that have long vexed thinkers. Gilgamesh, the titular character of an epic poem etched some 4,000 years ago on clay tablets, was obsessed with overcoming mortality. Chinese Emperor Qin Shi-Huang, who died in 210 B.C., drank mercury hoping to cheat death.
“Aging has excited the imagination throughout the history of humankind,” said Carlos Lopez-Otin, a biochemist at the University of Oviedo in Spain who co-wrote the hallmarks paper, “But it’s only recently that it has been subjected to profound scientific scrutiny.”
One hallmark attracting attention is changes in the epigenome, which consists of chemical compounds and proteins that can attach to DNA and regulate whether genes are turned on or off. Some researchers think an accumulation of errors in the epigenome drives aging and that removing the errors by “reprogramming” cells could lengthen life.
Shinya Yamanaka, a Japanese stem-cell researcher, shared a Nobel Prize in 2012 for discovering proteins that reprogram a cell’s epigenome to its embryonic state.
Scientists have used the proteins to extend the lifespan of mice and reverse blindness in mice and monkeys. Biotechnology companies such as Altos Labs, which Yamanaka advises, Retro Biosciences and Calico Life Sciences, part of Google parent Alphabet, are probing whether cellular reprogramming could extend lifespans or improve health.
