History of Aging Research
Aging is a phenomenon that humans have been intrigued by for millennia, stretching as far back as the days of Aristotle and Plato.
Plato, a Greek philosopher from 400 B.C., characterized aging and disease as two different phenomena. While Plato’s teachings tend to be slightly elitist, in his eyes, we all age. By living a healthy life, one can create harmony between the movement of the soul and body.
Aristotle, a student of Plato’s, thought that aging led to the deterioration of mental intellect. He did not make a distinction between aging and disease, as Plato did; instead, Aristotle proposed aging to be a natural disease that comes with a natural loss of intellect.
While aging piqued the interest of early philosophers, for years, the scientific community did not seem to care about aging. It was considered a part of the evolutionary process, and aging, from an evolutionary perspective, was nothing more than natural selection.
Even further, most animals died at young age due to predation, disease, human intervention, and food scarcity — so studying aging did not seem like a necessity. It wasn’t until the late twentieth century that solid evidence emerged suggesting that it was possible to increase human lifespan in the absence of evolution.
The Birth of Aging Research
In the early 1900’s, scientists began studying the mortality rates and curves of single-celled organisms, mice, and humans. Interestingly, they realized that most mortality curves had a similar structure; nearly all organisms had higher mortality rates in older age.
The conclusion was also made that it is not possible to stop the aging process, but rather, scientists realized that the rate of aging could be slowed, and that the same species could live drastically different lifespans depending on the type of intervention.
One of these interventions is termed caloric restriction and brought these promising findings into the spotlight. CR is just as it sounds: cutting back on the amount of food an organism consumes. Treatment with CR can lead to an increase in both lifespan and maximum lifespan of a species.
The first studies on CR were conducted in mice. They were fed a diet that was 30 to 40 percent less than their normal caloric intake. Today, it is widely accepted that CR also prevents age-related illness in most organisms.
The value in studying interventions to increase lifespan and healthspan began to grow. In 1988, a biology professor at the University of Houston, Michael Klass, studied worms to understand the genes involved in aging. Worms were genetically modified with a compound called ethylmethanesulfonate and studied extensively. It turns out that these worms lived longer than the average wild, non-modified worm.
Researchers working off Klass’s studies found that some of the C. elegans that lived longer lives had reduced activity in their age-1, PI3-K, gene. This led researchers to discover the insulin/insulin-like growth factor 1 (IGF-1)-like signaling pathway. Mutations in various components of the IIS were found to increase lifespan. For example, Professor Cynthia Kenyon from the University of California, San Francisco discovered that a single mutation in the daf-2 gene, which encodes an insulin receptor, can nearly double the lifespan of C. elegans worms.
Thus, Klass’s findings paved the way for aging research. Aging researchers continue to craft studies based off Klass’s studies even today.
First Studies Impact Today
Studies on CR also continued developing throughout the 20th century and into present day. A 2020 study fed rats 30 percent fewer calories than their ad-libitum counterparts and compared the differences between the diets at 18 and 27 months of their lives (the equivalent of 50 to 70 years of age in humans).
An intense evaluation of the genetic changes in these rats found that 57 percent of the age-related changes that occurred in normal rats did not occur in the calorie-restricted rats.
And, a 2021 study of C. elegans worms discovered something Klass did not: the power of the tumor suppressor phosphatase and tensing homolog protein (PTEN).
PTEN is a tumor suppressor, which means that it helps to keep the cell from engaging in any unhealthy behavior. Within the PTEN protein is a single strand amnio acid that supports health and longevity, while counteracting other naturally decreasing biological changes. This study offers the promise of a small genetic tweak that can help keep organisms healthy while also promoting longevity.
C.elegans and the studies conducted on them brought aging research to where it is today, but the discovery and study of anti-aging compounds also contributed greatly to the growth of aging research.
An easy way to help you live longer is to eat grapes, some berries, and peanuts. This is due to an anti-aging compound, called reversatol, that is found within these foods.
Scientists are also looking into metformin, a drug typically prescribed to manage Type 2 diabetes, for its anti-aging benefits. Metformin has been shown to slow aging in model organisms and reduce the incidence of age-related diseases in humans, such as neurodegenerative disease and cancer; though, just how metformin does so remains unknown.
Another compound under study is that of rapamycin, a drug that was initially developed as an immunosuppressant for organ transplant patients. A 2009 study found that rapamycin extends lifespan in mice, and research has since demonstrated the compound’s effects on cardiac disease and function, the central nervous system, immune system, cell senescence, and other areas of interest for anti-aging.
Into the Future
Considering that aging research has only taken off in the past 40 years, the possibilities of future studies are endless. There could one day be a lab-approved treatment for extending healthspan and allowing humans to live longer and healthier.
At the Center for Healthy Aging, we recognize that aging affects all of us, and by understanding it, we can tackle some of its root causes and effects. Browse our faculty directory to see how our affiliates are studying aging across disciplines.
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ABOUT THE AUTHOR
Grace Weintrob is a junior majoring in Communication Studies with a minor in Stage, Sports, and Film Production at CSU. She is currently working as the digital media intern for the Columbine Health Systems Center for Healthy Aging.