In potential breakthrough research, experts are measuring cell and tissue decline to better understand how we age and to make better aging therapeutics.
Published by Brett J. Weiss 2 April 2021
https://www.nmn.com/new1s/what-is-biological-aging
How do we define aging? Historically, we’ve counted the number of times we live while the Earth orbits the sun (chronological age in years), but nowadays we can also think about the accumulation of cell and tissue damage (biological age). Right now, the aging research field is having a “eureka” moment — we’re rapidly uncovering how and why we age and potential aging therapeutic options. What we’re starting to see is that the topic of biological aging is a key to understanding the aging process and may provide a means to achieve milestone, aging-related discoveries.
Getting at the heart of crucial biological concepts will help us understand what researchers are doing in this defining moment in the study of aging. These topics range from the level of DNA molecules and chromosomes to cells and tissues of the body.
Aging researchers have proposed that DNA damage that causes chromosome instability — where chromosomes lose structural integrity — is a primary cause of aging, affecting the quality of our cells’ molecular machines (proteins) that the DNA codes for. The underlying accumulation of DNA mutations, a concept referred to as “mutational load”, extensively contributes to chromosome instability. The idea is that with passing years, spontaneous, deleterious DNA mutations build-up resulting in “mutational load.” Although the aging effects of these mutations remain murky, such as how they alter proteins, DNA mutations seem to correlate with aging in tissues like skeletal muscle.
Another hot topic in biological aging research is chromosome end length. Scientists refer to these chromosome ends as “telomeres”, which appear to decay with age. What we’re finding is that the enzymes that facilitate their repair (telomerase) can’t keep up with their fraying and decay as aging progresses. So, researchers have sought ways to measure biological age by looking at chromosome end health, however, how telomere length affects aging remains unclear.
Another growing aging research concept is about cellular aging or “senescence.” When cells become senescent, that means they’ve reached an age-related, non-proliferating state. Researchers are still trying to figure out how senescence gets initiated. Interestingly, one way that cells become senescent appears to be linked to telomere shortening. Overall, quantifying senescent cell accumulation and burden on the body may provide an informative way to track biological aging. In fact, this method to measure biological aging may soon enter clinical research and medical practice, providing hope in elucidating the processes underlying aging.
Another way to measure aging is based on epigenetics, which is based on the accumulation of molecules that ornament our DNA called “methyl groups.” Studies show that “epigenetically older” individuals with more DNA methyl groups have a higher risk for developing age-related diseases. So, to measure biological age epigenetically and determine age-related disease risk, researchers have developed tools to measure and analyze accumulating patterns of DNA methyl groups. These techniques measuring biological age can help to determine what variables play into how fast passing years take a toll on the body and may also lead to methods to possibly even reverse biological age by manipulating patterns of DNA methyl groups.
The mitochondria, commonly referred to as the cell’s powerhouse, can also provide a way to measure biological aging. Mitochondria exist throughout the body, as cells need them to generate energy. As we age, mitochondria lose their ability to generate energy, which can lead to fatigue and age-related metabolic disorders. Research has shown that taking supplements called NAD+ precursors, such as nicotinamide mononucleotide (NMN), can boost mitochondrial production and function with possible effects on increasing energy levels and preventing age-related diseases.
The health of our blood vessels, or vascular health, can serve as biological indicators (biomarkers) that predict the occurrence of death (mortality). By applying what we know about blood vessel health and mortality risk, we can get a better idea of how fast people age.
These biomarker indicators of blood vessel health include measures of blood pressure and altered blood flow through vessels as well as blood vessel stiffness and the accumulation of plaque and calcium (calcification). Other blood vessel markers of aging not related to vessel structure and function include DNA mutations, markers of inflammation called interleukins, and protein-based indicators of blood vessel dysfunction. Perhaps in the future, by looking at these blood vessel biomarkers in younger adults, we can prevent age-related diseases and optimize solid health-related choices that improve each individual’s longevity.
From using methods to measure biological aging to finding ways to prevent and mitigate age-related diseases, biological aging research is in its heyday for helping scientists who study aging make discoveries. Not only will measuring biological age help with predicting age-related diseases, but it can also help us study how people age and what factors contribute to their aging. New molecules, like NMN and other popular NAD+ precursors, can also help us to minimize the damage from aging and prevent age-related deteriorating health. Combinations of NAD+-boosting molecules along with other anti-aging compounds may pave the way to lifespan extension therapies in the future. In due time, it’s probable that research will continue to provide insight to help us get a better handle on biological aging to improve our quality of life and help us live longer. Treating aging itself could also lead to breakthrough discoveries in age-related disease treatments for ailments like cancer, stroke, diabetes, and Alzheimer’s disease.
