Scientist at @harvardmed and @WyssInstitute in @geochurch's lab | Working on solving aging
Joined October 2019
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Alex Plesa retweeted
So proud to have been part of this work on cellular rejuvenation through identity-preserving reprogramming, out now in @NatureAging! Grateful to my mentors @geochurch @amplesa and all of our co-authors. nature.com/articles/s43587-0…
Our paper is out in @NatureAging. We looked for factors that make old cells' gene expression young without erasing their identity. SRSF1 came out as a promising rejuvenation target that reduced aging hallmarks in human cells and extended median lifespan of aged mice by 14%.
1/4
ALT Watercolor-style graphic of two overlapping cells split by a curved diagonal. On the left, a muted gray cell with a dark nucleus and faint white circuit traces. On the right, the same form in luminous blue, its circuitry lit up. Short dashes standing for RNA transcripts scatter loosely in gray on the left and fan outward in blue and pale green arcs on the right. Art by Helen H. Wang.
Alex Plesa retweeted
There's a new imaging modality in town: functional ultrasound imaging. I went down a deep rabbit hole to understand how it works computationally. Read all about how it works physically and how *you* can improve it..
Alex Plesa retweeted
In 12 weeks, we built a research facility that is run entirely by AI.
AI designs, executes, and observes experiments end-to-end across biology, chemistry, and materials science.
We’re introducing SciUniverse: a benchmark that measures AI’s ability to do real-world scientific research.
Alex Plesa retweeted
Science – debatably the #1 journal in the world – published a paper on a "virtual biotech" AI system this week
but the authors never even test if it works well!
all the evidence for its performance is 3 anecdotes
the paper has no benchmark scores, no baselines, no replicates
Alex Plesa retweeted
One of the most comprehensive studies of human mutations across tissues and age was released last week. 53 cell types, 172 people, ages 0-93.
Many takeaways, but the big highlight is that mutation rates vary a lot - and not in the ways you'd expect.
A thread:
Alex Plesa retweeted
We’ve just published what we believe is the first clinical trial of a treatment for primary age-related sarcopenia in cats. 💊😼
In a randomized, double-blind, placebo-controlled trial, our multi-target therapeutic showed significant positive effects on key measures of age-related muscle loss vs. placebo. 💪
A step toward treating one of the most consequential and under-studied manifestations of aging in cats.
Preprint linked in the comments.
Alex Plesa retweeted
41 outstanding progress intellectuals joined the 2026 Blog-Building Intensive Program.
Alex Plesa retweeted
No, we're not on the brink of ending aging. More clickbait, even from prestigious scientific magazines that should know better.
Why not? A short 🧵
1) The strongest lifespan-extending intervention in mice is caloric restriction, discovered nearly a century ago. So even in animals we haven't truly made much progress on how to slow (much less reverse) aging.
2) Our understanding of the aging process and its cellular and molecular drivers is still poor - which helps explain 1).
3) There is no proven intervention that retards human aging itself.
Cellular reprogramming is an exciting technology with many companies* and labs now working on it. It may have important clinical applications, including the current clinical trial for glaucoma - fingers crossed!
But while reprogramming allows cells to be rejuvenated in vitro, we don't yet understand whether or how it can be used safely and effectively in whole organisms.
And rejuvenating cells isn't the same as rejuvenating an organism. Remember that an immortal cell is a cancer cell, so rejuvenating a cell may or may not be beneficial in an organism made of many different types of cells. We know from mouse experiments that reprogramming can induce cancer, so it needs to be carefully controlled and tailored to the tissue and context.
*Disclosure: I'm CSO of YouthBio, a company developing rejuvenation gene therapies based on cellular reprogramming.
Are We on the Brink of Ending Aging?
nationalgeographic.com/healt…
Alex Plesa retweeted
AI transformed coding, science is next
@ReactorfieldAI makes scientists and deep tech startups AI-native
Built by me and @berkbuilds to accelerate science with frontier AI
Alex Plesa retweeted
Just published on Substack: Why Epigenetic Rejuvenation Won’t Give Us Radical Life Extension — Lessons from 58 Generations of Cloned Mice.
This is my take at the results of a landmark Nature Communications paper (20+ years, 1,200+ mice, 58 generations of serial cloning with full epigenetic reset) shows it still collapses. Mutations accumulated 3× faster. Epigenetic reprogramming works… until it doesn’t. There is an irreducible level of damage that cannot be undone.
To my taste, this is a very important study. Popular literature claims cloning erases aging signatures. In short-lived species it may look that way — the entropic damage simply doesn’t have time to kill. In longer-lived animals we expect the picture be very different (and there is an anecdotal evidence for that with a lot fewer generation before the collapse).
This is also why I dislike the language of “information theory of aging.” Flipping the sign on entropy and calling that "information" (changing from the Boltzmann to Shannon equation) doesn’t repeal thermodynamics.
Of course, you can still hope for better Yamanaka factors or else. My interpretation of the experiment is not yet a proof of anything - certainly not. However, the experiment removes a lot of ground under proponents of epigenetic rejuvenation.
If you want to keep your identity, better to stop aging than try to reverse it.
Challenge me. Subscribe, Like & repost. Link: peterfedichev.substack.com/p…
Alex Plesa retweeted
long-lived species and humans living 100+ years are known to have increased DNA repair capacity
but how DNA repair could be boosted to extend human lifespan is largely unknown
our research in Nature Aging today proposes a target to enable such a boost: the DREAM complex
Alex Plesa retweeted
AI has transformed how we design therapeutics.
But targeted delivery is still an expensive guessing game.
Today @BobbyHollings and I are launching @deliverome with @beckypferdehirt and @radialscience at @AsteraInstitute, to fix that. 🧵
Alex Plesa retweeted
Some thoughts on why it's so hard to find a cure for aging — tarkhov.ae/age-time-reversal…
🤖 Made with AI
Alex Plesa retweeted
1/ How long do you want to live?
For most of human history, aging was inevitable.
It's now solvable.
Apply for LBF8 cohort program: longbiofellowship dot org
/THREAD🧵
Alex Plesa retweeted
I’m excited to launch the Longevity Biotech Atlas, a personal project mapping 700+ organizations across the aging and longevity ecosystem.
Longevity biotech is moving fast.
A lot of the public narrative has centered on GLP-1s, peptides, biohacking, and consumer health optimization. But beneath that, a much deeper ecosystem is forming: companies, labs, investors, and non-profits working on core technologies that will enable fundamentally new forms of measurement and rejuvenation.
The field is growing quickly, but it is still hard to answer basic questions:
Who is building what?
Which areas are crowded?
Which technologies are underexplored?
Where should founders, scientists, investors, and operators be paying attention?
To help make the space easier to navigate, I synthesized public information on 700+ organizations—ranging from therapeutics developers, diagnostics, investors, and more— into a single database.
You can explore the atlas at the link in the comments.
This is still an early version, and I’ll be adding more over time: new organizations, personal accounts, bookmarks, and better ways to track how the field is evolving. My hope is to build this out into a core tool for people trying to understand, build, fund, or work in longevity.
If you’re interested in aging biology, biotech, investing, company formation, or the future of medicine, follow along. I’ll be sharing updates, maps of different subfields, and analyses of where the biggest opportunities and gaps may be. Let me know what you find useful!
Alex Plesa retweeted
Let’s stay at peak health without limits!
🧬 Vitalist Bay 2026 is T-30 days away
in Berkeley, CA from May 14-17.
Thanks to our partners, join this week & get:
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Alex Plesa retweeted
for a while i've had a slight fear that the bluetooth from my airpods could be frying my brain
this weekend i pulled the raw data from a $30m government study of 1,679 mice blasted with cell phone radiation and reanalyzed it
what i found was...not what I expected?
🧵
Alex Plesa retweeted
A reminder that cellular rejuvenation ≠ organismal rejuvenation
In mice, chemical reprogramming cocktails could be safely administered at lower dosages but with little benefits.
At higher dosages, they became toxic and required euthanasia.
In Vivo Chemical Reprogramming Is Associated With a Toxic Accumulation of Lipid Droplets Hindering Rejuvenation
onlinelibrary.wiley.com/doi/…
Alex Plesa retweeted
🧵 Elon: “Longevity is an extremely solvable problem”
At Vitalist Bay (May 14 - May 17), we’re solving it!
1K+ pioneers, 100+ speakers, 50+ workshops, 40+ activities, 5 critical health tests
Join us to spark dozens of SpaceXs for longevity!
Alex Plesa retweeted
How could tiny breakthroughs in aging science change U.S. GDP and population growth?
What’s the economic value of making 41 the new 40, or 65 the new 60?
How many lives could we create or save if we could slow reproductive or brain aging by just 1 year? What would billions of healthier hours be worth to the economy, if we assume no change in the age of retirement?
I spent the last two years obsessing over the design, research, and execution of this project. The result is a book upcoming with Harvard University Press, a preprint, and—maybe your favorite part—an interactive simulation tool that lets you input your own timelines and assumptions for specific breakthroughs in aging bio, then see the ROI in terms of US population & GDP growth.
From @RickEcon and Jason DeBacker—the economists who co-developed the open-source, macro model that made this project possible—to extensive comments by @tylercowen, @sapinker, Richard Freeman, @NDHendrix, @ebudish, @elidourado, @geochurch, @jasoncrawford as well as interviews with 102 scientists (!) and countless iterations with award-winning designer Giorgia Lupi and the @pentagram team, we built something we hope will be a benchmark for how scientists, economists, designers, philosophers, entrepreneurs and storytellers can come together to paint, fund, and build different flourishing futures for our species.
I couldn’t be more excited to share this. It’s the start of an open and evolving project—the labor and product of love, obsession, and unrelenting care.
I hope you have fun playing with our simulation tool — and if you do, please share!