A question of guts and brains

August 11, 2021 9:17 AM

Fecal transplants reverse signs of brain aging in mice (Science Magazine) – A new study published in Nature Aging shows a transplant of gut microbes, in the form of feces, from young mice to old ones can turn back the clock on the aging brain.

The first thing the team noticed was that the gut microbiomes of the old mice given young mouse microbes began to resemble those of the younger ones. The common gut microbe Enterococcus became much more abundant in old mice, just as it is in young mice, for example.

There were changes in the brain as well. The hippocampus of old mice—a region of the brain associated with learning and memory—became more physically and chemically similar to the hippocampus of young mice. The old mice that received young mouse poop also learned to solve mazes faster and were better at remembering the maze layout on subsequent attempts

Of course, mice aren’t humans so we "need to be careful to not over-interpret these findings":

We are not advocating faecal transplants for people who want to rejuvenate their brain. Instead, these studies point towards a future where there will be a focus on microbiota-targeted dietary or bacteria-based treatments that will promote optimum gut health and immunity in order to keep the brain young and healthy. Such strategies will be a more palatable elixir indeed.

posted by bitteschoen (73 comments total)

Many elderly people receive fecal transplants as part of a treatment for C. difficile infection. Presumably these transplants come from people who are generally younger than the treatment population, and if so that would seem like a natural experiment.
posted by jedicus at 9:37 AM on August 11, 2021 [13 favorites]

Well this lends a whole new context to the phrase "shit for brains".
posted by thecincinnatikid at 9:37 AM on August 11, 2021 [63 favorites]

I think I would eat the poop of life.
posted by Going To Maine at 9:37 AM on August 11, 2021 [4 favorites]

Metafilter predicted this. Or at least has always held that Peter Thiel is unnaturally full of shit.
posted by howfar at 9:45 AM on August 11, 2021 [5 favorites]

I thought it said "facial implants" and thought, "Oh, boy, this is gonna start a weird new trend!"

Not sure the proper reading is any better.
posted by dobbs at 9:45 AM on August 11, 2021 [3 favorites]

Instead of calling us Boomers they can call us y'all old sh☆theads.
posted by Oyéah at 9:46 AM on August 11, 2021

"these studies point towards a future where there will be a focus on microbiota-targeted dietary or bacteria-based treatments that will promote optimum gut health and immunity in order to keep the brain young and healthy. "

Sounds like a set-up for an ad :

Scientists say: Eat this food/take this supplement to rejuvenate your brain and gain optimum gut health!

The web is full of this kind of stuff.
posted by Billiken at 9:54 AM on August 11, 2021 [1 favorite]

I think immortality-obsessed billionaires should definitely over-interpret these findings in the most immediate and literal way possible. Tired: becoming a regular vampire to stay young. Wired: becoming a poop vampire to stay young.
posted by Pyry at 9:57 AM on August 11, 2021 [23 favorites]

2 Billionaires, 1 Cup
posted by GenjiandProust at 10:00 AM on August 11, 2021 [49 favorites]

The GI tract is an incredibly powerful part of the body that goes way beyond just digestion. It’s so cool! I’m not surprised to see fecal transplants having unexpected impact. It’s such a cool therapy - it’s amazing what it’s done for patients with chronic c dif.
posted by obfuscation at 10:02 AM on August 11, 2021 [8 favorites]

Back and forth forever
posted by brand-gnu at 10:25 AM on August 11, 2021 [20 favorites]

Of course, mice aren’t humans so we "need to be careful to not over-interpret these findings"

Sorry but I have already heard too much good news about this over the last 5 or so years, my thinking is "doesn't seem like it can do much harm, potential for very strong upside".

Keeping my eyes out for a fit, healthy, well organised and happy young man... yes it will be a strange conversation but hey, if it can change my life for the better... ?
posted by Meatbomb at 11:02 AM on August 11, 2021 [8 favorites]

I can think of more pleasant ways of getting healthy gut bacteria, like eating more yogurt or sauerkraut, (or pickles, kimchi, kombacha, etc).

We need a study that tells us which probiotic foods we can eat to make the gut microbes of the elderly look like those of the young, and to see if it has this same effect on the aging brain.
posted by eye of newt at 11:09 AM on August 11, 2021 [1 favorite]

Tbh, I’m torn about whether or not to post this to my Cdiff groups.FMTs have been game changers for so many people who suffered for years w recurrent Cdiff, but with insurance being what it is, DIY fecal transplants are definitely a thing.
posted by jacy at 11:10 AM on August 11, 2021 [2 favorites]

Looks like it has been somewhat of a mixed week for lab mice.
posted by acb at 11:17 AM on August 11, 2021 [16 favorites]

But eye of newt, I recall articles mentioning changes in things like BMI and even personality traits based on fecal transplants. I do not just want to have healthy guy bacteria, I want to be young again!
posted by Meatbomb at 11:19 AM on August 11, 2021 [4 favorites]

There are articles mentioning the same types of changes after eating particular probiotics.
posted by eye of newt at 11:24 AM on August 11, 2021 [2 favorites]

I'm also a little wistfully grumpy that I won't get to see what medical and biological understanding of the microbiome effects and interrelations and general entire internesting ecologies that makes up a person and that clause got very out of control, but what that'll look like in another hundred years of (dare to dream) continued improving civilization. It's sure to have some amazing things taken for granted ("back then, they just accepted massive shifts in their microbiomes as natural! that's practically bloodletting!") as well as museum dedicated to currently-seeming-promsing-but-actually-nonsense-in-future's-retrospect things ("this display is dedicated to the period of time they honestly thought tweaking gut populations affected memory, when actually as every schoolchild knows, vitamin X was only tenuously connected to c.diff levels").
posted by Drastic at 11:28 AM on August 11, 2021 [1 favorite]

healthy guy bacteria

I would prefer my bacteria to be gender-affirming, please.
posted by tigrrrlily at 11:30 AM on August 11, 2021 [3 favorites]

Keeping my eyes out for a fit, healthy, well organised and happy young man...

Strictly speaking, the study only showed that mouse feces reverses aging. So maybe try a pet shop?
posted by Pyry at 11:57 AM on August 11, 2021 [4 favorites]

It's yucky but not as spooky as using young people's blood.
posted by Nancy Lebovitz at 12:16 PM on August 11, 2021 [2 favorites]

HOUSE: He needs mouse poops to live!
posted by GCU Sweet and Full of Grace at 12:25 PM on August 11, 2021 [8 favorites]

Tired: becoming a regular vampire to stay young. Wired: becoming a poop vampire to stay young.

Elizabeth Báthory: I will bathe in the blood of virgins and live forever!

Court Physician: well erm actually your countess there's another therapy involving something from a young person that actually works

EB: Drinking blood directly from their necks?

CP: well ah not blood and not drinking and kind of involving the other end

EB: ...not following you

CP: You know, the other end

EB: oh hell to the nah

CP: but this one really works

EB: [sigh] oh OK washing the clots out of my hair was getting to be a drag anyway
posted by Halloween Jack at 12:30 PM on August 11, 2021 [7 favorites]

The most frustrating part of research like this is how many doctors dismiss it based on the ick factor. My mother had recurring C-Diff. Every time they took her off heavy antibiotics, the C-Diff would recur and she'd end up back in the ER. after the first few recurrences, we asked about fecal transplants but the doctors were dismissive. After 5 or 6 recurrences, they suggested she just stay on vancomycin forever. This is not a light decision - the drug needs to be kept refrigerated, and if you miss a day or two you end up back in the ER. These doctors considered that preferable to a fecal transplant because "that sounds gross". Luckily both mom and us are pushy, and had enough privilege to find other solutions - eventually she was able to enroll in a study of fecal transplants, and get one that way, and was cured.
posted by mrgoldenbrown at 12:42 PM on August 11, 2021 [43 favorites]

When people get fecal transplants, they do not eat the poop. It gets put directly into the colon, where there is already poop. Reference here. For that reason, I’ve never understood why everyone thinks it’s so gross. You don’t have to eat the poop, smell the poop, touch the poop, or interact with the poop using any of your other senses. It’s as uncomfortable as any colonoscopy, but it’s no more gross than the poop that is already there.
posted by snowmentality at 1:07 PM on August 11, 2021 [20 favorites]

MetaFilter: as uncomfortable as any colonoscopy
posted by nickmark at 1:09 PM on August 11, 2021 [9 favorites]

"You won't be able to tell but you'll have someone else's poop inside you" is not as strong a sales pitch as you seem to think.
posted by VTX at 1:10 PM on August 11, 2021 [11 favorites]

Personally, I think that it's kind of awesome that we're basically starships for bacteria.
posted by Halloween Jack at 1:20 PM on August 11, 2021 [20 favorites]

MetaFilter: eat the poop, smell the poop, touch the poop
posted by Wordshore at 1:29 PM on August 11, 2021 [4 favorites]

For that reason, I’ve never understood why everyone thinks it’s so gross
Mainly because of the idea of it being someone else's feces, really. Also keep in mind that most of the people undergoing fecal transplants are actually doing it the DIY way, at home, because it's not a recognized treatment that's widely available so those who have heard of it and want to try it (typically because of GI issues ranging from inflammatory diseases to more common IBS) do a bit of research online and find instructions on how to do it at home. This usually involves a partner or family member as donor. So it means you're going to have at least visual and olfactory contact with the fecal sample in question. It's not that terrible but yeah it's a bit more gross than when it's all done and processed in a lab.
posted by bitteschoen at 1:51 PM on August 11, 2021

2 Billionaires, 1 Cup

I really want to understand this joke but I just don't. Guess I had to be there.
posted by Bella Donna at 1:52 PM on August 11, 2021 [1 favorite]

I really want to understand this joke

No you don't, trust me.
posted by each day we work at 2:07 PM on August 11, 2021 [31 favorites]

All this knowledge is yours. Except "1 cup." Attempt no Googling there.
posted by It's Raining Florence Henderson at 2:11 PM on August 11, 2021 [12 favorites]

I like poop jokes but I’m sad they’re like 85% of the comments on this :(
posted by obfuscation at 2:20 PM on August 11, 2021

Bella Donna: "I really want to understand this joke but I just don't."

Just to reiterate: No. You. Don't.
I wish I didn't.
posted by signal at 2:21 PM on August 11, 2021 [4 favorites]

Out of curiosity I've just found and read two websites which detail doing an FMT at home ("Decide where you will do your FMT – either in a bath or lying on a towel on the bathroom floor. Avoid doing it on a bed or sofa or in a carpeted area in case you have a spill.") or in the office or workplace(!) Not linking to either as ... sketchy, and the recommendations and instructions were alarmingly different between the two. Can see some of the reasons why people attempt this procedure, though on some even sketchier websites it seems to be presented as a "cure" for just about everything.
posted by Wordshore at 2:31 PM on August 11, 2021 [1 favorite]

Fecal ‘transplant’ is effective orally as well as per a simple enema; colonoscopy is not necessary. See, for example https://jamanetwork.com/journals/jama/fullarticle/2664458 for a comparison of oral capsules vs. colonoscopy

Several methods have been used (freeze-drying, premedication with PPIs, etc.) but even simple encapsulation appears effective - at least for recurrent C. difficile. And, no need to approach relative strangers and have a difficult conversation. There are commercial and non-profit sources for properly screened feces (see https://www.openbiome.org/).
posted by sudogeek at 2:43 PM on August 11, 2021 [6 favorites]

Forget freezing your brain! Freeze your childhood poop!
posted by aniola at 2:53 PM on August 11, 2021 [5 favorites]

Mainly because of the idea of it being someone else's feces, really.

I pick up dog poop from 2 greyhounds each 1-3 times per day. My friends have kids who aren't yet potty-trained, and were it not for a pandemic, I might be babysitting and changing diapers.

If I can get a health benefit from proximity to poop, it's an upgrade to my daily existence.

Some of us just aren't as squicked out as others.
posted by explosion at 2:56 PM on August 11, 2021 [9 favorites]

I have a kid who is only partially potty trained (he poops in a bucket, oh joy!) and pick up poop from a 90lbs Akita every day. I would absolutely have this procedure if it was medically appropriate.

Still squickes me out.
posted by VTX at 3:03 PM on August 11, 2021 [4 favorites]

eventually she was able to enroll in a study of fecal transplants, and get one that way, and was cured.
posted by mrgoldenbrown

Epony… *nervous laugh*
posted by GenjiandProust at 3:12 PM on August 11, 2021 [4 favorites]

More researching indicates that cat faeces are not ideal and, in fact, can be highly dangerous when put inside the human body.

Good to know and means I'll never have to sift through a cat litter tray, like a gold rush worker in search of nuggets, for this purpose.
posted by Wordshore at 3:14 PM on August 11, 2021 [1 favorite]

So ok, a dating type app, but instead people post pictures of their perfectly formed and very attractive poop. Hard little lumps … swipe left!
posted by freecellwizard at 3:26 PM on August 11, 2021 [1 favorite]

I’m surprised to see in 2021 comments about doctors not knowing of or not performing FMT for C. difficle. I have been doing fecal ‘transplants’ in my GI practice for 2 decades plus, as have most gastroenterologists. This is first line therapy for recurrent CDI after failure of vancomycin retreatment.

And, so-called FMT has been tried - sometimes in small studies, sometimes only in case reports or by DIY adventurers - for numerous conditions including but not limited to ulcerative colitis, Crohn’s disease, microscopic/lymphocytic colitis, collagenous colitis, IBS, various rheumatologic conditions including lupus and RA, celiac disease, obesity, anorexia, and others, and in none of these have there been any controlled studies or even small series with definitive improvement. I have also seen patients who did DIY FMT which resulted in infectious colitis, while there are reports of serious complications like amebiasis, HIV, hepatitis, etc, from the use of feces from unscreened donors.

The efficacy of changing your native microflora by FMT (as compared to restoring a more normal microflora in a colon with abnormal flora after antibiotics and C. difficile infection) is not established. Several studies using antibiotic pretreatment to “prepare” the colon for the new microflora have suggested only transient presence of introduced bacterial DNA markers. (Measuring what the actual ‘microbiome’ is in some global way to determine this is very difficult as it consists of probably hundreds of species, some of which have never been cultured. Subtle changes in relative proportions of species, persistence of minor populations, and changes in the interaction of the mucosal immune system cannot be currently measured.) And, antibiotic therapy used prior to FMT for other conditions has resulted in, yes, C. difficile infection.

So, don’t do this at home.
posted by sudogeek at 3:36 PM on August 11, 2021 [41 favorites]

The director of Human Centipede may have missed best Oscar but must still hold some hope for the Nobel.
posted by biffa at 3:46 PM on August 11, 2021 [7 favorites]

I very occasionally prepared fecal transplants at my old job. We did a ton of donor testing for everything from giardia to HIV. We also prepared the transplant in a sterile room under a hood. We worked very closely with the ID docs to keep is safe as possible. I would never feel comfortable doing this at home.
posted by MaritaCov at 3:51 PM on August 11, 2021 [7 favorites]

I think immortality-obsessed billionaires should definitely over-interpret these findings in the most immediate and literal way possible.

To go this long in the thread and have no mention of John McAfee is a pretty big missed joke opportunity.
posted by tclark at 4:14 PM on August 11, 2021 [1 favorite]

Fecal ‘transplant’ is effective orally as well as per a simple enema; colonoscopy is not necessary.

Eat shit and not die.
posted by y2karl at 4:30 PM on August 11, 2021 [4 favorites]

I have a kid who is only partially potty trained (he poops in a bucket, oh joy!)

Yeah, the teenage years are rough, but it gets better.
posted by Literaryhero at 4:41 PM on August 11, 2021 [5 favorites]

"Knock knock"

"Who's there?"

"Gram."

"Gram who?"

"Gram negative."

"Step away from the back door."
posted by mandolin conspiracy at 5:39 PM on August 11, 2021

I guess it makes some sense that the digestive system should be so powerful; essentially every animal over a few cells is an elaboration of a gut tube. Most of the rest of our complicated bodies are built on the platform of those original cells, folded over and expanded and elaborated. And a great deal of that was for the purpose of more efficiently providing items for that gut tube to work on.

It still makes me feel a little strange, though!
posted by tavella at 5:56 PM on August 11, 2021 [5 favorites]

Give! Me! The de-aging poop!
posted by pelvicsorcery at 6:38 PM on August 11, 2021 [1 favorite]

I have absolutely no problem believing the gut and the brain are deeply linked - anyone who lives with an anxiety disorder is used to the digestive system going into, um, overdrive during an attack -- one way or another.
posted by tzikeh at 7:00 PM on August 11, 2021 [5 favorites]

I scurried down the rainy, crowded street under a sky so filled with ads it might as well have been a TV screen. In an inside pocket was 150g of black market shit, forcibly removed from some careless bunker-dweller when they had wandered into the wrong place.
I remembered what the Kakomancer said as he handed over the chilly steel cylinder. "Ten minutes late for delivery and this will only be useful for spreading on the nutrient tanks. As will you."
I shivered and moved on. This was my last chance to escape the distribution center dormitories.
posted by thatwhichfalls at 7:06 PM on August 11, 2021 [18 favorites]

sudogeek, there's a lot of work going on with microbiomes in livestock. Recognizing that ruminants are very different from monogastrics, I wonder just how much host control there is of the microbiome in humans. For example, if you swap the rumen contents between two cows, the transplanted microbiome will eventually "revert" to the original microbiome. This suggests that the host genome has considerable control over the microbial population, at least in the rumen. It's fascinating stuff.
posted by wintermind at 8:17 PM on August 11, 2021 [2 favorites]

I realize there's a large giggle/yuck factor, but if this pays off for people, it's good news.
posted by Nancy Lebovitz at 10:20 PM on August 11, 2021 [1 favorite]

Unfortunately, the zen approach won't help you overcome natural distaste for the idea, cause becoming one with the solution means you'll still be de turd.
posted by allium cepa at 10:24 PM on August 11, 2021 [2 favorites]

> Keeping my eyes out for a fit, healthy, well organised and happy young man...

I let the talent scouts do the work for me & buy my transplant material on the brown market.
posted by ASCII Costanza head at 11:25 PM on August 11, 2021

Some of us just aren't as squicked out as others.

Eh yeah I’m among those not easily squicked out too, but I was just observing that most people indeed are squicked out by the idea. Still if it’s done in a medical setting with proper procedures there’s a lot less of an ick factor involved.

But it’s true that there seem to be a lot of people doing it at home and that does involve more risks as well as more of a potentially "gross" situation of having to handle the poop. It was just an observation, not a recommendation for a DIY approach. Here’s an article on WebMD from six years ago, "The Rise of the Do-It-Yourself Fecal Transplant"
posted by bitteschoen at 3:23 AM on August 12, 2021

Wintermind, I’d suspect diet and local exposure way more than host genetics (at least in healthy people, most studies I know of have found little evidence of genetic control and a LOT of influence from diet and what microbes you’re exposed to). In humans microbiomes tend to be pretty stable over the medium term, barring major interventions, but over decades things do seem to get replaced.

Engraftment is a really weird process. My recollection is that post-FMT you see some really startling mixtures of changes (some donor strains engraft but not others, some recipient strains persist, sometimes things coexist, sometimes other stuff randomly shows up or goes away???). For as effective as it is in C. diff there’s a lot we don’t know about how the process works. Even when you’re transferring stuff into germ-free mice not everything in a complex human community ends up taking, for whatever mysterious reason.

Also just wanted to boost sudogeek’s excellent comment above about the clinical side of FMT.
posted by en forme de poire at 4:55 AM on August 12, 2021 [1 favorite]

And one of the take home messages — do not try this at home — cannot be overstated. A couple of people have even died in FMT trials from insufficiently screened donors who turned out to be asymptomatic carriers of something nasty, and those studies were way more rigorous than the average biohacker with a blender is capable of achieving.
posted by en forme de poire at 4:57 AM on August 12, 2021

2 Billionaires, 1 Cup

I really want to understand this joke but I just don't. Guess I had to be there.

It's a reference to a porn video called 2 Girls 1 Cup which I have not seen, but from reading people's jokes about it online I gather involves some shit play that is repulsive to most people.
posted by medusa at 5:06 AM on August 12, 2021 [1 favorite]

How is this any grosser than a solid organ transplant, which isn't gross at all? If you own a pet or have a kid or care for someone incontinent don't you interact with someone else's poop constantly? Most people wipe their own butts. Poop is a part of life. This is a medical procedure, so presumably unless you're doing it DYI you're not really doing much if you're the patient in the procedure. In any case it is super cool that poop--which is literally garbage--actually might have value!
posted by twelve cent archie at 6:06 AM on August 12, 2021

Just when you get old and well off enough to not have to eat anymore shit from other people they reel you back in.
posted by srboisvert at 6:26 AM on August 12, 2021 [2 favorites]

Well, at least it's no longer same shit, different day.
posted by acb at 8:35 AM on August 12, 2021

It's not the delivery of the transplant that's icky, it's the harvesting and handling of the material to be transplanted.
posted by entropos at 11:31 AM on August 12, 2021

I have eaten
the feces
that were in
the icebox

and which
you were probably
saving for old age

Forgive me
they were odorous
so moist
and so cold
posted by sjswitzer at 3:32 PM on August 12, 2021 [4 favorites]

So... its not a kink, its preserving your brain functionality... To be clear, I can see how this works... that scene in Pink Flamingo is permanently etched in my brain.
posted by Nanukthedog at 3:54 PM on August 12, 2021 [1 favorite]

[Geriatrician (geriatric medicine doctor) here. For years I was in a department that's one of the world's leading aging research centers.]

The study's endpoint is "aging-associated differences in peripheral and brain immunity, as well as the hippocampal metabolome and transcriptome of aging recipient mice." Why not make the endpoint be how long the mice lived? A laboratory mouse's lifespan is just two years.

Laboratory mice are super weird. They are inbred to an insane degree, the result of mating siblings for hundreds of generations. They're very different from wild mice.

I learned a lot over just the last couple of days from a recent 2.5 hour podcast episode with leading (like, really really leading) aging-biology researcher Steve Austad. It's here.
posted by neuron at 7:48 PM on August 12, 2021 [5 favorites]

Read the headline, came in to see if a "shit for brains" joke had been made yet. Comment number two. Nice!
posted by Serene Empress Dork at 5:17 AM on August 13, 2021

How is this any grosser than a solid organ transplant, which isn't gross at all?

Those organs are not made of POOP!
posted by VTX at 6:35 AM on August 13, 2021 [2 favorites]

In any case it is super cool that poop--which is literally garbage--actually might have value!

Just wait until you learn about the magic of manure! No, really, I can recommend at least one book if you're interested.
posted by aniola at 10:40 PM on August 13, 2021 [1 favorite]

The most frustrating part of research like this is how many doctors dismiss it based on the ick factor. My mother had recurring C-Diff. Every time they took her off heavy antibiotics, the C-Diff would recur and she'd end up back in the ER. after the first few recurrences, we asked about fecal transplants but the doctors were dismissive. After 5 or 6 recurrences, they suggested she just stay on vancomycin forever. This is not a light decision - the drug needs to be kept refrigerated, and if you miss a day or two you end up back in the ER. These doctors considered that preferable to a fecal transplant because "that sounds gross". Luckily both mom and us are pushy, and had enough privilege to find other solutions - eventually she was able to enroll in a study of fecal transplants, and get one that way, and was cured.

That really surprises me. In the UK the guideline is to try anti-microbials twice and then do a faecal transplant on third occurrence. I have spoken to at least one gastroenterologist who does them on second occurrence since if antimicrobials fail once, they are much more likely to fail a second time.
posted by atrazine at 3:40 AM on August 16, 2021