Scientists prove diseased blood vessels communicate with the brain
They were then able to follow the trace, allowing them to compare healthy against diseased mice and to directly identify the electrical connections.
In the rodents which had experimental therapy where the connections were severed, atherosclerosis was less developed than in the control mice.
Dr D’Agostino, a neuroscientist from The University of Manchester involved in the study and who is also a Medical Research Council Fellow, said: “Today we have the tools not only to visualise, but also to turn on or off nerve bundles connecting the brain with the body with unprecedented selectivity. This gives us a greater understanding of how the brain and other parts of the body are wired together during health and disease.
“The novel technologies we have been using make it possible to reduce the boundaries between disciplines that were previously working in isolation. And that, in the long term, could have a significant impact on the development of novel therapeutics and ultimately improve human health.”
Arteries have three layers, though plaques are only found on the innermost layer.
Scientists have long known that the innermost layers are not supplied by nerve fibres. “As such, no one has asked whether nerves come into contact with arteries in the case of atherosclerosis so this could open up a new understanding of atherosclerosis” says senior author Professor Andreas Habenicht, also from the University of Munich.
However, the team revealed that molecular sensors known as receptors, located in the outer layer of the vessels, play a key role.
The receptors recognize where plaques are located and where vessels are inflamed by identifying the inflammatory messengers of the inflammation.
Then the receptors at the nerve endings translate the inflammatory signals into electrical signals via nerves to the brain.
The brain processes the signals and sends a stress signal back to the inflamed blood vessel. This negatively influences the inflammation, and the atherosclerosis gets worse.
Co-senior authors Professor Daniela Carnevale and Giuseppe Lembo, from the University of Rome and the Neuromed Institute in Italy, studied mice in which electrical connections between a diseased artery and the brain were severed.
In mice which had the experimental therapy, atherosclerosis was less developed than in the control mice.
Image: Nerve bundles in the diseased artery external layer (adventitia) visualised as red, fluorescent filaments. Growing new nerve bundles are visualised as green, fluorescent filaments. Image credit: Dr Sarajo Kumar Mohanta
Image: artery that supplies the heart showing significant atherosclerosis and marked luminal narrowing.
The paper Neuroimmune cardiovascular interfaces control atherosclerosis is available here DOI: 10.1038/s41586-022-04673-6