The progress of a human life may be thought of as a gradual succession of changes from the egg to the tomb.
But if you wake up one morning, look in the mirror, and wonder how you’ve aged all this time, it might not be your imagination: According to a new study of the molecular changes that occur with aging, humans experience two dramatic aging surges, once at an average age of 44 and once at an average age of 60.
“We’re not just seeing gradual changes over time, we’re seeing really dramatic changes.” says geneticist Michael Snyder. from Stanford University and lead author of the study.
“We found that the mid-40s, as well as the early 60s, are a time of dramatic change, and this is true no matter what class of molecules we look at.”
Aging is complex and associated with an increased risk of all kinds of diseases. Snyder and his colleagues are investigating the biology of aging, seeking to better understand what changes occur and how they occur, in order to more effectively mitigate and treat these diseases. To this end, they have been following a group of 108 adults who provided biological samples every few months for several years.
They are Some conditionsAlzheimer’s disease Cardiovascular diseaseThe risk does not increase gradually over time, but increases exponentially after a certain age. So the researchers wanted to take a closer look at biomarkers of ageing to see if they could identify relevant changes.
Using samples from the cohort, the researchers have tracked a wide variety of biomolecules studied, including RNA, proteins, lipids, and gut, skin, nasal, and oral microbiome taxa, totaling 135,239 biological features.
Each participant submitted an average of 47 samples over a period of 626 days, with the participant who attended the longest submitting 367. This massive amount of data generated more than 246 billion data points that the researchers crunched to look for patterns of change.
Several previous studies have found nonlinear changes in molecular weight associated with aging. Rat and humanIn research on fruit flies, mice, and zebrafish, The gradual aging process in these species.
Snyder and his colleagues found that the amounts of different molecules in the human body changed very clearly in two stages: about 81 percent of the molecules they studied showed changes in one or both of these stages. The changes peaked in the mid-40s and again in the early 60s, but with slightly different profiles.
The peak in the mid-40s was associated with molecular changes related to lipid, caffeine, and alcohol metabolism, cardiovascular disease, and skin and muscle dysfunction, whereas the peak in the early 60s was associated with carbohydrate and caffeine metabolism, cardiovascular disease, skin and muscle, immune regulation, and renal function.
The first peak, in their mid-40s, is when women typically go through menopause or the peri-menopause, but the researchers ruled this out as a major factor because men also undergo significant molecular changes at the same age.
“This suggests that although menopause or premenopause may contribute to the changes seen in women in their mid-40s, there are likely other more important factors influencing these changes in both men and women.” Metabolite Xiaotao Shen, first author and author of the study, explains:Formerly of Stanford University, he is currently at Nanyang Technological University in Singapore.
“Identifying and studying these factors should be a priority for future research.”
The researchers note that their sample size was fairly small and they performed only limited testing. Biological The samples were taken from people aged between 25 and 70. Future research could look more into this phenomenon and, by studying a wider range of subjects in more detail, potentially provide a better understanding of how the human body changes over time.
This study Natural aging.
