Longevity Briefs: Release of Packaged Mitochondrial DNA Declines With Age

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: The mitochondria are the cell’s power plants, and they stand out from other structures within the cell because they have their own DNA – mtDNA. One theory suggests that damage to this DNA plays a central role in the ageing process. mtDNA from destroyed mitochondria can be released from the cell inside extracellular vesicles – small membrane packages that can carry messages from one cell to another. Might this mtDNA be linked to the ageing process?

What did the researchers do: In this study, researchers measured the quantity of mtDNA in extracellular vesicles from individuals between the ages of 30 and 64. This measurement was made twice for each individual, with measurements being made 5 years apart. They also introduced these extracellular vesicles into cell cultures, and studied the effects of ‘young’ vs ‘old’ vesicles on energy production by mitochondria.

Key takeaway(s) from this research: The quantity of mtDNA contained within extracellular vesicles appears to decline with age. This may simply be because the number of mitochondria within cells declines with age. It may also be because old cells are less able to destroy and clear damaged mitochondria. Whatever the case, this change may serve as a useful biomarker of ageing within middle-aged populations.

The study also found that cells exposed to ‘young’ extracellular vesicles produced more energy within their mitochondria than those exposed to ‘old’ vesicles. This suggests that extracellular vesicles contain signals that are important for mitochondria to function (though this doesn’t necessarily mean that mtDNA is one of these signals). In line with this finding, another study in 2019 reported that injecting extracellular vesicles could extend mouse lifespan.

Recommended Products