TL;DR
Turn quiet afternoons into listening time
- Thousands of audiobooks, podcasts and originals
- Listen on your phone, tablet or Echo — also offline
- Cancel anytime
A study published in Aging Cell found that autophagy patterns differed by age, sex and cell type in samples from healthy volunteers. A small exercise pilot in five older adults suggested blood-cell autophagy may shift after a 12-week program, but the finding needs larger studies.
Researchers at the Sanford Burnham Prebys Medical Discovery Institute found that autophagy varies with age, sex and cell type, rather than following a uniform decline in the human cells they studied. The findings, published September 27 in Aging Cell, challenge a common assumption about cellular recycling and may affect how scientists evaluate proposed healthy-aging interventions.
The team studied skin and blood samples from volunteers aged 23 to 72 who reported having no chronic diseases. Researchers also converted skin cells into induced neurons, allowing them to examine three cell types. They analyzed RNA transcripts to assess the expression of genes involved in autophagy and used a separate test to measure the rate of the cellular process directly.
In the results, autophagy declined with age in male skin cells, remained stable in female skin cells and increased in induced neurons from female participants. The study also found that autophagy-gene expression did not correlate with the direct measurement of cellular recycling activity. The researchers said that means gene-expression readings alone may not reliably indicate how quickly autophagy is occurring.
The team examined links between autophagy and physical function among adults aged 70 and older. Higher autophagy was associated with poorer physical-function measures across the cell types studied: blood-cell autophagy with lower aerobic fitness, skin-cell autophagy with higher body mass index, and induced-neuron autophagy with lower grip strength and metabolism and a higher resting heart rate. These are reported associations, not evidence that autophagy caused those outcomes.
Why One Aging Measure May Mislead
The results suggest that researchers cannot treat autophagy as a single process that changes in the same way throughout the body as people age. Cell type and sex mattered in this study, and the differences between gene activity and directly measured recycling raise a practical issue for research: a convenient molecular proxy may not capture the process scientists want to measure.
The findings also complicate the idea that increasing autophagy is always beneficial for aging. In participants aged 70 and older, greater measured activity was associated with poorer physical-function indicators. That does not establish that higher autophagy is harmful; it does suggest that its meaning may depend on age and other factors. The study is relevant to work exploring autophagy as a target for healthy-aging interventions, but it does not establish a treatment or prove that changing autophagy improves health.
As an affiliate, we earn on qualifying purchases.
How Researchers Measured Cell Recycling
Autophagy is a cellular process that breaks down and recycles damaged or unneeded material. It is often discussed in aging research because reduced autophagy has been linked with age-related disease, but the study’s authors said evidence for a simple decline in humans is limited. Senior and corresponding author Caroline Kumsta said the team wanted to test that assumption in healthy individuals.
The study combined two approaches: analysis of RNA transcripts related to autophagy and a direct measurement of autophagy rates. It also included an exploratory exercise pilot. Five adults aged 77 to 88 provided blood samples before and after a 12-week, mild exercise program focused on fall prevention. The researchers reported that blood-cell autophagic activity appeared to decrease toward levels they described as more youthful, alongside improved physical performance. The pilot’s small size limits what can be concluded.
“We commonly see people cite this idea that autophagy declines with age, but the actual evidence for this in humans is very thin.”
— Caroline Kumsta, senior and corresponding author
As an affiliate, we earn on qualifying purchases.
Limits of the Human Evidence
The supplied report does not state the total number of volunteers in the main study, making it difficult to assess the size and representativeness of that sample. Participants self-reported that they had no chronic diseases, and the reported results do not establish that age or sex caused the differences. The exercise findings are especially preliminary: they involve five participants, blood-cell measurements and a 12-week program, so they cannot show whether the same changes occur in other tissues or persist over time.
It also remains unclear why higher autophagy was associated with poorer physical-function measures among older adults, whether those associations hold in larger groups, and what level of activity might be beneficial at different ages. The study does not show that exercise should be used to alter autophagy or that doing so prevents disease.
blood autophagy measurement device
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Larger Exercise Studies Underway
The researchers said larger studies with more participants and improved testing protocols are underway with the Exercise and Physical Activity Resource Center at UC San Diego. The lab has received a pilot grant from UC San Diego’s Altman Clinical and Translational Research Institute to extend work on exercise, autophagy and physical function in aging.
Those studies may help test whether the blood-cell changes seen in the small pilot are reproducible and how they relate to fitness and physical performance. Further work will also be needed to establish whether findings differ across tissues, ages and sexes before autophagy measurements can reliably guide potential interventions.
As an affiliate, we earn on qualifying purchases.
Key Questions
What did the study find about autophagy and aging?
It found that autophagy did not change uniformly with age in the cell types examined. Patterns differed by cell type and sex, including a decline in male skin cells, stable levels in female skin cells and an increase in female induced neurons.
Does the study show that autophagy causes poorer health in older adults?
No. Among adults aged 70 and older, higher autophagy was associated with some poorer physical-function measures. The study does not show that autophagy caused those differences.
Did exercise change autophagy in the study?
A pilot involving five adults aged 77 to 88 found that blood-cell autophagic activity appeared to decrease after a 12-week mild exercise program. The small pilot is preliminary and does not establish a general effect.
Can gene-expression tests show how much autophagy is happening?
Not reliably on their own, according to the study. Researchers found that autophagy-gene expression did not correlate with their direct measurement of cellular recycling rates.
Source: rss
Cold & flu season Picks
humidifiers
As an affiliate, we earn on qualifying purchases.
