Introducing the brain: brain, eye immunity one system (Introduction)

by David Turell , Tuesday, April 30, 2024, 18:52 (17 days ago) @ David Turell

Traced though lymphatic system::

https://www.the-scientist.com/keeping-an-eye-on-brain-immunity-71806?utm_campaign=TS_Ne...

"As an extension of the central nervous system, the eyes share an anatomical connection with the brain that is key to an animal’s ability to see. Besides the visual connection, both the brain and the eye are considered immune-privileged sites, wherein the immune response to pathogens is highly controlled to preserve the organ’s functions and minimize potential damage to tissues that do not easily regenerate.1 Despite both organs bearing the immune-privileged tag, the brain has received far more attention than the eye, according to Eric Song, a physician scientist at Yale University. This prompted Song to take a closer look at eye immunity.

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“'We say that the eyes are the windows into the soul. This paper shows that they are also the windows into the immunology of the brain,” said Jonathan Kipnis, a neuroimmunologist at the Washington University in St. Louis, who was not involved in the research.

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"The lymphatic system helps remove byproducts and pathogens from tissues and allows the movement of immune cells to sites of infection throughout the body. To map the ocular drainage system, the scientists injected a fluorescently labeled molecule into the anterior and posterior chambers of mouse eyes. They found that these compartments drained into different lymph nodes, with the posterior chamber, or vitreous, draining into the same lymph nodes in the neck that receive drainage from the brain.

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"...the team surgically damaged the lymphatic vessels that flow to the deep lymph nodes (dLN), structures in the neck into which the vitreous and brain drain their byproducts. They found that these lymphatic structures are necessary for eye-brain immunity since mice with dLN ligatures succumbed to HSV-2 challenge in the brain, as do nonimmunized animals.

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"...the researchers investigated the organization of this lymphatic network, which was not well understood. By combining a spatial transcriptomic approach with immunolabeling of lymphatic vessel markers, the team identified a lymphatic vasculature in the optic nerve sheath, a very thin membrane that covers the optic nerve. Intravitreal administration of the lymphatic stimulator vascular endothelial growth factor C (VEGFC) increased the drainage of a fluorescent molecule to the dLN, indicating that this vasculature functionally supports the vitreous drainage to these lymph nodes.

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"...the researchers investigated the organization of this lymphatic network, which was not well understood. By combining a spatial transcriptomic approach with immunolabeling of lymphatic vessel markers, the team identified a lymphatic vasculature in the optic nerve sheath, a very thin membrane that covers the optic nerve. Intravitreal administration of the lymphatic stimulator vascular endothelial growth factor C (VEGFC) increased the drainage of a fluorescent molecule to the dLN, indicating that this vasculature functionally supports the vitreous drainage to these lymph nodes."

Comment: the blood brain barrier is quite strong. Finding a lymphatic system that works for both brain and eyes is not surprising since the eyes are an extension of the brain. As usual a great logical design.