Everyone loses their youthful glow eventually, as the process of aging drags on. But while age is the single most unifying quality of humans, it's also a multifaceted and complex phenomenon, leaving scientists baffled for centuries — with many wondering whether a unifying causal mechanism underlies aging, or if it's caused by a composite result of several disparate factors.
However, scientists recently found that DNA damage is responsible for most — if not all — features of aging, which hints at the possibility of a unifying cause behind the way time drags us down, according to a recent study published in the journal Nature.
DNA damage is most responsible for aging phenotypes
Physically speaking, any organism is a consequence of both its genetic makeup and its environmental influences. Gentotypes are unique genetic patterns you inherit from your biological parents, whereas phenotypes can change due to epigenetic modifications, which can include environmental and lifestyle influences — such as great stress, trauma, diet, socialization, and many other factors.
For example, our genes determine the quantity and kind of melanin our bodies produce, which creates skin color. But ultraviolet (UV) light exposure in sunny regions can darken existing melanin and lead to the production of more melanin — and thus darker shades of skin.
Aging is linked to a wide scope of features at the molecular, cellular, and physiological level — which involves genomic and epigenomic alterations, a decline in the general cellular and subcellular function and deregulation of signaling systems, and the loss of proteostasis. But until now, the relative roles of each factor over one another hadn't been clearly ordered into a hierarchy of causal significance. And the new study collected evidence that suggests that DNA damage is most responsible for aging phenotypes.
However, it's one thing to understand how aging works, and it's another thing entirely to engineer new methods of slowing or reversing the aging process.
In May of last year, a reverse aging procedure involving giving young rat plasma to aged rats successfully reversed epigenetic changes in the animals — which resulted in improved organ functions and cleared senescent cells. That study — initially posted on a preprint biology server — effectively reverse-aged the rats by 54%.
Efforts to reverse aging in humans might focus on repairing DNA damage
In the same month of 2020, MIT neuroscientists discovered an enzyme — known as HDAC1 — that might be vital in repairing age-related DNA damage to cognitive and memory-linked genes. HDAC1 levels are lowered in people suffering from Alzheimer's, and the elderly in general. But the MIT researchers suggested we might reverse the effects of aging or cognitive loss in their study, which was published in the journal Nature Communications.
In it, the scientists noticed how DNA damage in mice was correlated with lowered levels of HDAC1 enzyme, but then improved after injection with a drug that (re-)activates the enzyme.
"It seems that HDAC1 is really an anti-aging molecule," said the Director of MIT's Picower Institute for Learning and Memory Li-Huaei Tsai, who was also senior author of the study, in a Science Daily report. "I think this is a very broadly applicable basic biology finding, because nearly all of the human neurodegenerative diseases only happen during aging."
"I would speculate that activating HDAC1 is beneficial in many conditions," added LiHuaei Tsai.
And perhaps with more research into the newer study — which suggests that DNA damage is responsible for most (if not all) aging symptoms in humans, efforts can be made to focus the development of the HDAC1 enzyme-activating drug and the finding that reversed aging in mice by 54%. This work could ultimately lead to new and better ways to restore DNA to its youthful glory, and give ordinary people a chance to overcome their social or economic disadvantages.
After all, with a long enough timeline, nearly everyone could ultimately improve their lives beyond the limits in which most are born.