A New Record for the Longest Lived Laboratory Rat, Resulting from Plasma Dilution

Many more life span studies are carried out in mice rather than rats, so it is not too surprising to see people pushing the record for longest lived rat. The longest lived mice are those in which growth hormone receptor signaling is inhibited, while the longest lived rats are the result of life-long calorie restriction. The group noted here is pursuing a strategy of processing the blood plasma from young animals and then introducing the processed plasma into old animals. A treatment starting in mid-life produced a modest gain in median life span in rats, while the one still surviving rat from the small study group has surpassed the existing record for calorie restricted mice. It is an interesting data point for the field of dilution of blood plasma to reduce harmful factors present in the bloodstream of old individuals, though as I understand it, this group favors explanations involving factors from the processed young plasma that are beneficial.

Scientists working on an experimental anti-ageing therapy claim to have broken a record by extending the lifespan of a lab rat called Sima. Named after the Hindi word for "limit" or "boundary", Sima is the last remaining survivor from a group of rodents that received infusions of blood plasma taken from young animals to see if the treatment prolonged their lives. Sima, who was born on 28 February 2019, has lived for 47 months, surpassing the 45.5 months believed to be the oldest age recorded in scientific literature for a female Sprague-Dawley rat, the researchers say. So far, Sima has outlived her closest rival in the study by nearly six months.

Researchers have rushed to produce and trial therapies based on young blood plasma after numerous experiments found that infusions could reinvigorate ageing organs and tissues. The results from the latest study will be written up when Sima dies, but data gathered so far suggests that eight rats that received placebo infusions of saline lived for 34 to 38 months, while eight that received a purified and concentrated form of blood plasma, called E5, lived for 38 to 47 months. They also had improved grip strength. Rats normally live for two to three years, though a contender for the oldest ever is a brown rat that survived on a restricted calorie diet for 4.6 years.

Results from such small studies are tentative at best, but some scientists believe the work, and similar efforts by others, has potential. A preliminary study found that infusions of young blood plasma wound back the biological clock on rat liver, blood, heart and a brain region called the hypothalamus. A patent filing on the potential therapy describes how plasma from young mammals is purified and concentrated before use. Some components, such as platelets, are removed, as they can trigger immune reactions.

Link: https://www.theguardian.com/science/2023/feb/08/anti-ageing-scientists-extend-lifespan-of-oldest-living-lab-rat


This is Harold Katcher's lab, and is a follow-up experiment to well-publicized research he did showing epigenetic age reversal (as verified by Horvath) using young-to-old plasma fraction infusions. E5 is what he is calling the combination of blood signaling factors he has been using. I've been following updates on this experiment (there is a youtube channel that was coming out with updates every few months) and I recall that Katcher was somewhat disappointed with the early results of this experiment. It looked like the mortality curve was not dramatically different from untreated rats iirc. The explanation was that the original experiment used all male rats, and this newer experiment used all female rats, and that E5 would have to be somehow modified for use in females for some reason.

Pretty exciting that despite E5 (apparently) working less well in female rats than male rats, the lab was nonetheless able to set a longevity record. I hope they follow up with a lifespan study using E5 in male rats.

Overall, this experiment gives more credibility to the aging-as-signalling-error-cascade camp (though the Conboys of course think of aging as primarily pro-aging signaling of some sort, and Katcher thinks of aging as pro-youth signaling).

Posted by: gheme at February 16th, 2023 8:49 AM

Great news. It would seem any Patent application in this area would necessitate that the Patent applicant assert that there are beneficial effects to the young plasma. Filing a Patent application which merely asserted that dilution of old plasma is beneficial would likely not get Patent approval. And thus, imo, the entire Elixir 5 protocol is probably a charade to get Patent approval on plasma dilution..It is noteworthy that the literature explicitly states that no specific components of E5 are identified as being beneficial

Posted by: JohnD at February 16th, 2023 1:15 PM

This is not a plasma dilution experiment. The results are from injecting pro-youth factors derived from young plasma of another species. The patent covers both aspects the creation of the pro youth biologic and success in cross species sourcing of them. The latter patent solves a major dilemma of sourcing young plasma from teenagers. Cross species sourcing allows for the waste of the meat industry to become raw material for production of the pro-youth factor biologic. Thereby giving scalability and keeping the treatment pricing affordable.

Posted by: Akshay at February 17th, 2023 2:25 PM

This is inaccurate and misleading. You should consider rewriting it, unless of course it was intentionally prepared as such. It is interesting that the name of the Rat (Sima) is mentioned, but the name of the company that does this experiment (Yuvan), and the lead scientist (Harold Katcher), are not mentioned.

Posted by: Zisos Katsiapis at February 19th, 2023 3:22 PM

In the article is says "The results from Katcher's latest study will be written up when Sima dies, but data gathered so far suggests that eight rats that received placebo infusions of saline lived for 34 to 38 months, while eight that received a purified and concentrated form of blood plasma, called E5, lived for 38 to 47 months." That means that E5 is not dilution, as the control rats received placebo saline infusions. It means that E5 works better than dilution.

Posted by: Nina at February 24th, 2023 9:09 AM

it would be interesting to have in such a study a second control group, with albumin dilution only...

Posted by: SilverSeeker at February 24th, 2023 10:31 AM

Checking in on this months later, now that we know more about what they've been up to. I'm surprised there's not more talk about this around here. They're using porcine plasma and believe high quantities of exosomes to be responsible for the rejuvenative effects. Katcher has recently done several interviews where he has made some exceedingly ambitious claims (of the sort that can only elicit skepticism) believing this to essentially be the Eureka moment for aging and akin to the fountain of youth, and even says he has rejuvenated his own right hand by applying E5 to his skin. He regularly shows the supposedly rejuvenated hand on camera and while it does look significantly younger than his left appendage it's obviously impossible to know whether E5 is the cause. He says they're planning to get E5 to market as a topical cosmetic application soon, as it won't face the same regulatory roadblocks as will the ultimate goal of providing intermittent intravenous therapy for systemic rejuvenation. Of course, if this product is other than snake oil then even as a topical application it will absolutely disrupt the entire cosmetic industry and change the world, so here's hoping. I welcome the critical opinions of any resident scientists.

Posted by: Ben at October 8th, 2023 4:13 AM
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