Søren Grubb🔥🔥🔥Exciting news! I just published a preprint on the #Ultrastructure of #PrecapillarySphincters and the #NeurovascularUnit. This study is based on the https://www.microns-explorer.org/ dataset by @AllenInstitute. Check 🧵 for more details, including movies of the findings. (1/15)
Introduction: Precapillary sphincters are indentations of the #capillary lumen at where it branches from an #arteriole. With colleagues I have previously shown their location 🗺️ and function 🧑🔧 (https://tinyurl.com/euasfses). (2/15)
‼️Importantly, #PrecapillarySphincters exist where a #Capillary branches from a much larger #Arteriole (≈upper cortical layers) but not when there is a more gradual transition (≈lower cortical layers). (3/15)
The function 🧑🔧 of the #PrecapillarySphincter is to control the #BloodFlow to the #Capillaries, securing adequate distribution of blood flow between the upper and lower cortical layers. For more, check these🧵: https://bit.ly/3hUEytP and https://tinyurl.com/4e2w3x9n (4/15)
Søren Grubb @[email protected] on Twitter
“Today our #neuroscience #research #paper about #PrecapillarySphincters in the #Brain is live on @NatureComms: https://t.co/dIQb5Cr3BG. I’m so proud of our work @Uni_Copenhagen @UCPH_Health @Neuroscience_dk and would like to share it with you in the following tweets. #happy (1/10)”
Results: In this study of the #MICrONS 🐭👁️-cortex 3D #ElectronMicroscopy dataset, I show how the shape of #Contractile #MuralCells transition from #PenetratingArteriole to #PrecapillarySphincter to #Capillaries. Vascular lumen = blue, mural cells = various colors (5/15)
At the #PrecapillarySphincter and #NeurovascularUnit, I show: #EndothelialCell, #MuralCell, #Fibroblast, #Macrophage, #Astrocyte and #Neuron. Also, structures: #ContractileElement, #MyoendothelialJunction, #PinocyticVesicle, #Collagen, #Elastin, #Glycocalyx (6/15)
#MyoendothelialJunctions are 🔗s between #MuralCells and #Endothelia, elsewhere separated by the #BasementMembrane. I show how #Brain #PrecapillarySphincters are 🔥spots for these junctions (yellow dots), like Rhodin showed in 🐇 #PeripheralTissue: https://tinyurl.com/cm8chj56 (7/15)
#Collagen is mainly synthesized by #Fibroblasts, strengthening #Arteriole and #Capillary vessel wall. #Ultrastructure shows #fibripositors where #collagenfibril #tripelhelixes are made and #fibrils that reach across the #PerivascularSpace (8/15)
#Astrocytes are generally depicted as #Parenchymal somas with processes reaching the #bloodvessels. Here, I show that #AstrocyteSoma are part of the #Endfeet around #PenetratingArterioles and #AscendingVenules (9/15)
🐭#Brain #Microvasculature is not #Innervated. But #Parenchymal #NeuronalProcesses arrange perpendicular to #Arteriole direction where #PerivascularSpace exists, while #AscendingVenules do not have this arrangement (10/15)
#Human🚶♀️#Brain 🧠 has similar arrangement of #NeuronalProcesses around #Microvasculature. Shown here for a #FirstOrderCapillary and an #AscendingVenule in the #H01release 3D #ElectronMicroscopy 🔬 dataset: https://tinyurl.com/mvvunjax (11/15)
Conclusion: In the #Brain 🧠, #Microvasculature is not #Innervated like in #PeripheralTissue. #PrecapillarySphincters and/or #FirstOrderCapillaries are central to #NeurovascularCoupling, which may be enhanced by perpendicular alignment of #NeuronalProcesses (12/15)
If you enjoyed this🧵, please read my @biorxiv_neursci #Preprint: https://tinyurl.com/5yfx5d8p. If you have suggestions on how to improve the #Manuscript, please comment using the comment function in BiorXiv (13/15)
Motivation for study: Lack of independence has been a major criticism in my #RejectedStartingGrant application reviews. I have been working on this project mostly as a hobby, but I have also used some time @neuroscience_dk funded by @novonordiskfond via @MartinMlauritz (14/15)
I would appreciate suggestions for what #Journal to submit to 🙏. I have no personal grants to pay #PublishingCosts or do supporting lab experiments, so the journal would have to understand my situation and waive the costs 🤷 (15/15)