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Kate Cavanaugh @katecavanaugh.bsky.social · 6d

Happy Fluorescence Friday with this new preprint 👀

Kate Cavanaugh @katecavanaugh.bsky.social · 8d

See this? This = implanting mouse embryo. Usually this happens inside its mother and is invisible to us, but we can actually watch implantation ex vivo with the hope of understanding why implantation goes awry in embryos of older women. A 🧵...

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Reposted by Kate Cavanaugh

Ricard Alert Zenón @ricardalert.bsky.social · 7d

New job, new preprint! We found that embryo implantation can be understood as active wetting! Embryos from older mothers have trouble implanting because they are too contractile and viscous. Check out the wonderful thread (and movies!) by @katecavanaugh.bsky.social.

www.biorxiv.org/content/10.1...

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Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thank you!!! This was a fun paper to do/write. But Aren't we all just really really really old embryos anyway? 🤣😅

Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thanks Vicky!! I hope you're doing well!

Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thanks Rikki! I hope all is well with you! 💪

Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thanks for the kind words, mark!!

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Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thanks Vinny! I hope you and yours are doing well!!!

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Reposted by Kate Cavanaugh

Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Amazingly, yes! Here, we indexed embryos, calculated compaction metrics, and selected Normal and Accelerated tempo’d embryos for later implantation assays. We find compaction metrics correlate with ultimate implantation potential – for both aged and young maternal conditions.

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Reposted by Kate Cavanaugh

Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Well, we also find increased contractility in the aged embryo also correlates with faster compaction at the 8-cell stage. Could this be a possible metric to see which ones will implant?

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Reposted by Kate Cavanaugh

Kate Cavanaugh @katecavanaugh.bsky.social · 8d

But contractility tunes cell-cell adhesion (limiting spreading) and cell-substrate adhesion (promoting spreading). Aged embryos show higher blastocyst surface tension AND higher spreading forces via Traction Force Microscopy. Weird… So how can we explain reduced spreading?

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Reposted by Kate Cavanaugh

Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Using mouse embryos, we visualize implantation in vitro to see what’s wrong in embryo development w/ advanced maternal age. In vitro implantation assays show aged embryos do not implant as efficiently.

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Kate Cavanaugh @katecavanaugh.bsky.social · 7d

Thanks for following along. We hope this info can be used to improve IVF procedures to increase success rates for women of all ages. Please like/RT. @eshre.bsky.social #eshrejc @bwfund.bsky.social @hhmi.org #reproductivehealth #reproductivehealth #devbiol

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

We stand on the shoulders of giants! Many other groups have looked at compaction metrics - like the extent of embryo "flattening" as a way to show viability. But we hoped that we could fill the gap as to whether compaction itself correlates with later implantation potential 💪

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

we heavily used the Spirochrome dyes for this paper!

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Reposted by Kate Cavanaugh

bioRxivpreprint @biorxivpreprint.bsky.social · 8d

A mechanical origin for implantation defects in embryos from aged females https://www.biorxiv.org/content/10.1101/2025.09.29.679218v1

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

A profuse thank you to all collaborators - Diana Laird, @pwoakes.bsky.social , and @ricardalert.bsky.social – whose hard work really elevated our findings. Thank you to Orion, who gave me incredible freedom to explore this new research in the lab.

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

And finally, can we rejuvenate embryos to restore developmental potential? We hope yes – by tuning embryonic contractility we may find the embryonic fountain of youth to improve fertility if this holds true for human embryos.

a close up of a person 's face with the words `` i want to be forever young '' .

ALT: a close up of a person 's face with the words `` i want to be forever young '' .

media.tenor.com

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

What this also suggests is something out of Willy Wonka – we can use early compaction metrics to find the good and bad embryos. Talk about an Eggdicator…

a little girl in a red dress is standing in front of a scale ..

ALT: a little girl in a red dress is standing in front of a scale ..

media.tenor.com

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

To summarize - we find that there is an optimal contractile regime for embryos to undergo proper development/implantation. Contractility shifts the proportion of optimal embryos in each maternal condition.

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Amazingly, yes! Here, we indexed embryos, calculated compaction metrics, and selected Normal and Accelerated tempo’d embryos for later implantation assays. We find compaction metrics correlate with ultimate implantation potential – for both aged and young maternal conditions.

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Well, we also find increased contractility in the aged embryo also correlates with faster compaction at the 8-cell stage. Could this be a possible metric to see which ones will implant?

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

So, seems like age-related implantation defects are driven by the egg/embryo itself! But how can we pick the good embryos that are competent to implant in IVF procedures? Can we leverage this mechanical info of implantation competence?

Egg Dfk GIF

ALT: Egg Dfk GIF

media.tenor.com

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Enter theory! We modeled embryos like a liquid droplet wetting on a surface. We find age-related spreading behaviors are explained by increased tissue viscosity, which limits implantation spreading. Imagine a droplet of water vs honey spreading…

a black and white photo of a drop of water falling from a bottle on a concrete surface .

ALT: a black and white photo of a drop of water falling from a bottle on a concrete surface .

media.tenor.com

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

But contractility tunes cell-cell adhesion (limiting spreading) and cell-substrate adhesion (promoting spreading). Aged embryos show higher blastocyst surface tension AND higher spreading forces via Traction Force Microscopy. Weird… So how can we explain reduced spreading?

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Kate Cavanaugh @katecavanaugh.bsky.social · 8d

Implantation is inherently a mechanical process. We find contractility is necessary and sufficient for spreading behaviors. We can artificially age embryos from young females and even rescue aged embryo spreading just by tuning contractility!

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