Wendy W @WendyW@qoto.org

First, a recap. After COVID infection (especially with the early variants) many/most folks lost their sense of smell - for most it was transient (days-weeks) but for some others much longer (months-years). So how does SARS-CoV-2 actually attack your sense of smell?

Odors are detected by olfactory sensory neurons (OSNs) in your nose, which send information about odors to the brain. These sensory neurons are surrounded by support and stem cells, which enable OSN function and renewal of the olfactory epithelium (which gets banged up every time you breath through your nose).

At the beginning of the pandemic we (including Brad Goldstein, Darren Logan, Hiro Matsumani, John Ngai, Matt Grubb and others) hypothesized that SARS-CoV-2 infects support/stem cells but not OSNs themselves. Since then many studies have explored this issue - most are consistent with the hypothesis that support cell infection and possibly the loss of support cell function indirectly causes sensory neuron dysfunction = transient and/or long term loss of smell

Two key studies from human autopsies (from Stavros Lomvardas and Peter Mombaerts) revealed that in people the virus likely infects support cells and not OSNs, and further that after COVID there are hallmarks of inflammation that could affect OSNs. Animal models also suggested that the nose might be subject to all sorts of immune-mediated madness (see work from Ben tenOever).

But what is going on in living patients suffering from long-term smell loss?

To explore this idea, Brad's lab performed biopsies of the olfactory epithelium from patients with post-COVID smell loss (objectively documented via testing), followed by single cell sequencing to enable definitive cell type identification (side note - in the field there is a lot of confusion about how to identify cell types).

There is a lot of data in the paper, but the most important observation is the presence of an immune infiltrate comprised of T cells and myeloid cells, just camping out in the epithelium of patients with long term smell loss; there is no evidence of viral RNA, but support cells are clearly responding to immune signals. There are also fewer OSNs, there are changes in OSN gene expression, and there is evidence that stem cells may not be renewing the epithelium effectively.

These findings lead to a model in which support cell infection triggers a cascade that culminates in immune infiltration, OSN dysfunction and long-term smell loss. The data argue that persistent smell loss is immune mediated, suggesting possible new strategies for patient treatment; these results are also broadly consistent with the idea that neuroinflammation is the main way SARS-CoV-2 impacts the nervous system.

Our findings are also relevant to long COVID, which affects many other organ systems, and is also thought to be at least in part immune mediated. Many questions remain (why do some patients get their smell back quickly while others have this immune infiltrate and long term loss?). Looking forward to continuing to work on this important problem - congrats to all the authors (and thanks to the patients!)

So, I'm finding out the hard way that if you start a new Mastodon server, nobody can find you.

This is a shameless request for some boosts so some of the bigger instances see me.

#mastodon #twittermigration #mastodonserver #findme #helpimtrappedinawell #imlonely

#london

If you're interested in the present and future of fusion energy then I recommend this 30-minute video. Really in-depth look at Helion's process for generating electricity.

https://www.youtube.com/watch?v=_bDXXWQxK38

BIG NEWS: New York Mayor #EricAdams has announced a “reimagining of Fifth Avenue — from Bryant Park at 42nd Street to Central Park at 59th Street — as a safer, less congested, pedestrian-centered boulevard that also prioritizes cyclists, mass transit, & the public realm.”

This is one I’ll be watching!
https://www.nyc.gov/office-of-the-mayor/news/917-22/mayor-adams-moves-reimagine-fifth-avenue-bryant-park-central-park

#NYC #NewYork #NewYorkCity #urbanism #cities #StreetsForPeople #cities #city

I'm testing out my first pinned post. I'm #newhere and finding my way around. I'm here to learn about things to do with better #cycling and #walking and to share what I'm learning as I go.

My day job is running the new agency responsible for cycling, walking and wheeling in England - Active Travel England. Busy times :)

I’ve said it before. These things are complete game changers. As usual, a car driver cut me up from the inside on Lambeth Bridge roundabout (south side horrendous layout) but with the e-bike you can move faster to avoid danger caused by drivers. If the saddles could go slightly higher then = dream bike for me #radfahren #cycling #mobility

#Introduction Hi all, I’m a developmental neurobiologist running a lab that uses brain #organoids to uncover mechanisms that make the human brain special. Follow me for interesting papers in this sphere, updates on our research, and fun science things I find along the way!

Excited for an #introduction 👋!

📝 We are Penn NeuroKnow, a #neuroscience blog run by PhD students in the University of Pennsylvania’s Neuroscience Graduate Group.

👩‍🔬 👨‍🔬 Our goal is to share our love of neuroscience with you all. Each post breaks down a different topic in neuroscience, ranging from general neuroscience knowledge to summaries of exciting new studies that are changing how we think about the brain.

🧠 Recent topics have included why we get the hiccups, how the octopus controls its arms, and how neuroscientists are starting to realize that what they thought was noise might not actually be so noisy.

⏰ We’ll be sharing links to our latest posts with short summaries every Tuesday when they go live. We’re looking forward to sharing our posts and engaging with the community here!

https://pennneuroknow.com/

#sciComm #scienceCommunication #writing #blog #neuro #PhDStudent

"William Hogarth’s Satire on False Perspective (1754), engraved by Luke Sullivan, offers an Escher-like array of impossible lines and vanishing points: a man lights his pipe from a distant candle; a flock of sheep grow bigger as they recede round a corner; a foreground flag disappears behind a distant tree, and many more."

https://publicdomainreview.org/collection/william-hogarth-satire-on-false-perspective?ref=the-browser

Oh, wow, Tom Lehrer has released all of his songs into the public domain. Apparently also his website will shut down "at some date in the not too distant future" so now's a good time to download directly.

"In short, I no longer retain any rights to any of my songs.
So help yourselves, and don’t send me any money."

https://tomlehrersongs.com/

European Union negotiators reached agreement early on Sunday morning (18 December) to reform the EU’s Emissions Trading Scheme (ETS), the biggest carbon market in the world and the bloc’s flagship climate policy instrument.

https://www.euractiv.com/section/emissions-trading-scheme/news/eu-agrees-carbon-market-overhaul-in-bid-to-hit-2030-climate-goal/

Kindness Can Have Unexpectedly Positive Consequences

https://www.scientificamerican.com/article/kindness-can-have-unexpectedly-positive-consequences/

#science
#blackmastodan

Philosophy article recipe https://www.keithfrankish.com/philosophy-article-recipe/