Thread: Thanks to @ECTS_science for inviting me to speak today on What is New in Basic Bone Biology Techniques at #ECTS2021. It is an overview of many interesting papers over the past 18 months, so to make it simple for listeners, here’s a thread of the papers I’ll discuss. 1/21
Osteoclast fission and fusion was first proposed in 1946, in this beautiful image from Hancox who wished he could see it live with “microcinephotography”. https://physoc.onlinelibrary.wiley.com/doi/10.1113/jphysiol.1946.sp004153 #ECTS2021 2/21
75 years later this is reality with intravital imaging and fluorescent reporter mice. @michbal19 @LabPhan @GarvanInstitute recently published videos of osteoclast fusion and fission, tracking osteoclast recycling. Videos in the paper. https://www.sciencedirect.com/science/article/pii/S0092867421001525 #ECTS2021 3/21
Intravital imaging has also been used by @SDallas_lab to visualise osteocyte dynamics in real-time; osteocyte dendrites move in and out of their canaliculi! https://pubmed.ncbi.nlm.nih.gov/32512167/ #ECTS2021 4/21
Visualising the osteocyte network means we can start to map its beautiful complexity – there are 23 trillion connections in the osteocyte network, and enough dendritic processes to go 4x around the world #BiggerOnTheInside https://pubmed.ncbi.nlm.nih.gov/25708054/ #ECTS2021 5/21
The Ploton silver stain reveals the complexity and variability of the osteocyte network Thanks to @TamaraAlliston for making this stain so popular. It’s important to note that this stains the canals of the network, not the cells. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3728487/ #ECTS2021 6/21
The dendritic processes can be quantified – it’s very challenging! But this has been done by a few studies, including this one from @jboerckel’s team noting a change in dendritic morphology with YAP/TAZ deletion. https://asbmr.onlinelibrary.wiley.com/doi/full/10.1002/jbmr.3876 #ECTS2021 7/21
Measuring the network, this time with confocal imaging has now shown that the structure of the network is an excellent predictor of response to mechanical load. @afvantol’s work is stunning! Look at the paper to see videos. https://www.pnas.org/content/117/51/32251 #ECTS2021 8/21
That study focussed only on a slice of bone. Another recent study also used in vivo micro-computed tomography to show the response to mechanical load is co-ordinated at the organ level, leading to the increase in curvature. @apitsillides50
https://advances.sciencemag.org/content/6/10/eaax8301 #ECTS2021 9/21
https://advances.sciencemag.org/content/6/10/eaax8301 #ECTS2021 9/21
We’ve been using in vivo microCT @SVIResearch and noted that as bone matures, the level of mineralisation changes, even after shape is established. We measured bone mass at multiple densities. This revealed how bone matures with age. https://elifesciences.org/articles/56666 #ECTS2021 10/21
We’ve also published a method paper @bioprotocolbyte to make it easy for others to do it too. I hope you’ll give it a try. https://bio-protocol.org/e3873 #ECTS2021 11/21
Here’s the paper that I had to skip due to lack of time! It shows how the muscle pushes against bone as it grows, changing bone shape, even in young adult mice. An inspiring paper from @audreeq18 @GordonSLynch
https://asbmr.onlinelibrary.wiley.com/doi/10.1002/jbm4.10477 #ECTS2021 12/21
https://asbmr.onlinelibrary.wiley.com/doi/10.1002/jbm4.10477 #ECTS2021 12/21
Some beautiful imaging with fluorescent-tagged antibodies and reporter mice has brought the bone vasculature back to our attention. This paper really showed very convincingly that, just like human bone, murine bone is heavily vascularised: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6795552/ #ECTS2021 13/21
Again, this is a new way of looking at something very old, and just like human studies, we have known for a long time that rodent bone is vascularised. This excellent review provides some good historic context https://anatomypubs.onlinelibrary.wiley.com/doi/abs/10.1002/ar.24461 #ECTS2021 14/21