Key Points:
- Rats treated with exosomes lived about 10% longer on average than non-treated rats.
- Exosome-treated rats also showed enhanced physical performance as demonstrated by a grip strength test.
- Sima, one of the exosome-treated rats, survived approximately four years—recognized by the North of England Rat Society as the longest a rat has ever lived.
Blood plasma from young mice has been shown to alleviate signs of aging and extend lifespan in older mice, making way for some human zealots attempting to prolong their lives by trying blood transfusions from younger donors. All the same, the exact way that young blood rejuvenates tissues and prolongs life in these animals has remained somewhat of a mystery. However, more recent research has shown that exosomes derived from the blood of young mice can also extend the lives of older mice. This research supports the notion that young blood plasma may work to extend lifespan, at least in part, through effects from exosomes.
Following this line of thought, some researchers have questioned whether exosomes derived from certain mammal species—like pigs—may work to alleviate signs of aging and extend lifespan for other species. Along those lines, Katcher and colleagues from Yuvan Research in California have published a report in Aging Cell showing that exosomes from pigs modestly extend lifespan in aged rats. The pig-derived exosomes also improved physical performance as measured with grip strength. Perhaps the most notable thing from the study was that one rat in the group treated with exosomes was recognized by the North of England Rat Society for living the longest of any known rat—four years. These findings provide a hint that tissue rejuvenation and lifespan extension from young blood plasma, at least in rodents, could be, in part, a result of effects coming from exosomes.
For background, exosomes are nano-sized vesicles released from cells that travel through bodily fluids like blood. These interesting, microscopic structures are thought to shuttle proteins, fats, and pieces of DNA and RNA between cells. Accordingly, exosomes are believed to play key roles in communication between cells.
Pig-Derived Exosomes Extend Lifespan and Improve Physical Performance
For their study, Katcher and colleagues began with aged female rats that were intermittently injected with exosomes derived from the blood of young pigs. Interestingly, the rats that received the pig-derived exosome injections lived, on average, about 10% longer than those that did not. These data suggest that pig-derived exosomes extend lifespan in rats. Importantly, this finding also provides the first evidence that exosomes from young mammalian organisms, in this case pigs, can be transferred to older organisms of another species—rats in this study.
To get a better handle on whether the exosomes reverse signs of aging like reductions in physical capacity, Katcher and colleagues measured grip strength after treatment with exosomes. Interestingly, they found that the exosome injections significantly improved grip strength. Furthermore, this measure of physical function did not trend toward tapering off to the same degree over the course of aging as it did for non-treated rats. By measuring grip strength as a proxy for overall physical function, the researchers’ data suggested that exosomes restore age-related physical decline, which can be a major feature of aging.
Perhaps most noteworthy, one rat in the study, named Sima, that was treated with pig-derived exosomes lived approximately four years. Hence, according to the North of England Rat Society, Sima broke the record for the longest that any known rat has lived. This adds to the intrigue of the publication in that it appears that exosomes coming from young pigs propelled the longest lifespan of any rat recorded to date.
Determining Whether Humans Can Use Pig-Derived Exosomes to Delay Aging
How exactly exosomes may rejuvenate physical function and extend lifespan in rats remains a topic of debate amongst aging researchers. Katcher and colleagues say, though, that they have confirmed through unpublished data that exosomes contain long fragments of DNA and RNA—termed nucleic acids. According to a study, one major age-related change identified in cells is the loss of longer fragments of RNA, many of which are associated with longevity genes. In that regard, the Yuvan Research-based scientists say replacing the missing fragments of RNA with those from long RNA-containing exosomes may be one means by which exosomes restore more youthful physiological function.
What’s more, the finding that exosomes can be taken from a young organism like a pig and used to rejuvenate another organism like a rat begs the question of whether people could one day use pig-derived exosomes as an aging intervention. More trials are needed with animals to confirm efficacy before moving to human trials. All the same, the possibility remains that we may one day be able to use pig-derived exosomes to ward off the ravages of aging.
“I don’t like the idea, but it’s no more unethical than eating a meat sandwich,” said Katcher regarding human usage of pig-derived exosomes in a press release. “When those pigs are killed they still have a lot of life in them. We just use that extra life instead of throwing it away.”
Even if people could start injecting pig-derived exosomes into their circulation, it is still unclear whether the effects would be short- or long-lived. In that sense, these exosomes could enhance our physical function or other physiological parameters for a while, but whether they would provide long-term, whole-body rejuvenation against aging would be another question.
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