Past research into aging was characterized by a driving philosophy of "look but don't touch". Intervention in the aging process was presented as exclusively the domain of fraud, lies, and marketing, exemplified by the activities of anti-aging marketplace, all hope and non-functional potions. To treat aging was an aspiration that every scientist was strongly encouraged to avoid by those who controlled the research agenda and its funding. This was the case from at least the 1970s until comparatively recently. Only in the past decade or so has the scientific community come around to accept the treatment of aging as a possible, plausible, desirable goal.
That change in attitude was sweeping and comprehensive. Now there is an increased level of funding for the study of mechanisms of aging, and the primary arguments held in public are are over how best to achieve a lengthening of the healthy human life spans. The first rejuvenation therapies have started the lengthy and expensive process of making their way out of the laboratory and into the clinic. Others will follow in the years ahead. These are the early years in an era of rejuvenation, in which the healthy human life span will leap upward as a result of treatments that address the molecular damage that drives aging.
Every major cause of death and disability in the developed world shares a greatest risk factor, and it is probably not what most people would think. Smoking, obesity, a sedentary lifestyle, and drinking too much alcohol all contribute to disease: however, their contributions are small in comparison to the physiological changes that result from aging. Whether biological aging causes the many functional declines that occur with age, or just permits them, is perhaps open for debate, but there is no question that, for most of us, biological aging determines how and when we and our loved ones will get sick and die.
This connection between aging and disease has become particularly consequential during the COVID-19 pandemic, with the vast majority of severe cases and deaths occurring among the elderly. Given this obvious relationship, it is somewhat surprising how slowly the biomedical research community has come to appreciate the importance of biological aging in many of the disease processes under study.
Today, unfortunately, too many scientists study individual diseases without recognizing the impact of aging biology. It is still common, for example, to see research studies in cancer, neuroscience, metabolism, and other fields where young animal models (such as 4-6 month old mice) are used to study disease processes that almost exclusively occur in old people. 'Mice are not people' is a standard refrain when explaining why so many preclinical therapies fail in human trials. Perhaps the mouse isn't the problem. Failing to account for the physiological changes that occur during aging, both in mice and in people, may be a much bigger reason why so much preclinical research fails to translate to the clinic.
Thinking about certain conserved molecular mechanisms as 'hallmarks' or 'pillars' of aging has benefited researchers within the field, and has also allowed scientists outside the field to begin to recognize how aging biology impacts on their own research. Another important advance in aging research has been the development of a concept called geroscience: researchers in this area seek to understand mechanistically how the hallmarks of aging cause age-related disease and functional decline. The growth of the geroscience concept also reflects a recognition that aging research is much closer to clinical application than it was twenty years ago. Numerous interventions have been developed that target one or more of the hallmarks of aging in order to delay, or even reverse, age-related functional declines.
The future of aging research is brighter than ever before, and the pace of discovery is only increasing. We look forward to major breakthroughs over the next few years that will revolutionize the way we think about aging biology and have the potential to significantly impact human healthspan and longevity.