As people age, maintaining a positive and predictable social environment becomes more and more important.
For instance, keeping close ties with friends and family has been identified as one of the key ingredients to healthy aging.
In a study from Arizona State University and elsewhere, scientists found that maintaining a positive social environment can help stave off some of the key stressors and challenges of aging.
They found that in macaque monkeys, females with a higher social status had younger, more resilient molecular profiles, providing a key link between the social environment and healthy brains.
This study builds upon more than 15 years of work by the team investigating the interactions between social behavior, genetics, and the brain in the Cayo macaques.
The group they have studied is a population of free-ranging rhesus macaques living on the isolated island of Cayo Santiago, Puerto Rico.
When the team grouped each sample brain region by age, 8 distinct clusters of genes stood out.
Among the most interesting were those involved in metabolic processes, cell signaling, and immune and stress responses.
Next, they homed in on their analysis to magnify the prefrontal cortex area of the brain at a single-cell level.
They also revealed strong parallels between macaque and human gene expression signatures of age.
Some of this variation was specific to regions associated with degenerative neurological diseases, while others reflect conserved neurological patterns associated with older age across the whole brain.
But not all the findings found parallels in humans, suggesting that there may be root causes of some neurodegenerative disease that are also part of what make us uniquely human.
These key differences between the effects of age in macaques and humans could help explain the unique mechanisms underlying some human neurodegenerative diseases.
Next, the team applied their data to the social aspects of macaque aging, which have several unique features.
They found in female macaques low social status is associated with increased mortality, and its effects on immune cell gene expression are similar to gene expression signatures of aging in humans.
They found that the effect of rank on gene expression was particularly driven by younger molecular profiles in high-ranking females, suggesting that associations between higher rank and younger brain age are not expressed linearly along the social hierarchy but instead are specific to females with the highest ranks.
High social status may confer several advantages, including increased access to resources, more predictable environments, and decreased harassment from group mates.
These findings provide some of the first evidence of molecular parallels between aging and social adversity in the brain—providing a key mechanism linking adverse (or conversely, beneficial) environments and earlier onset and faster progression of age-related brain decline and disease.
If you care about brain health, please read studies about a major cause of depression in older people, and these antioxidants could help reduce dementia risk.
The study was conducted by Noah Snyder-Mackler et al and published in Nature Neuroscience.
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