This study shows links between Long COVID’s neurological effects, including brain fog and cognitive decline, and brain blood vessel integrity, offering hope for new treatments and diagnostic methods.
https://www.nature.com/articles/s41593-024-01576-9 (open access)
Bringing in a medical perspective since there is a lot of subtle misunderstanding in the comments section:
The source study is not referring to “brain bleeding” or “mini strokes” as a cause of long COVID—the results point more towards a breakdown of the integrity of the blood brain barrier and maybe micro vascular ischemia.
You can essentially think of your central nervous system (brain and spinal cord) as being surrounded by a very selective security system called the Blood Brain Barrier (BBB). The BBB exists to prevent certain chemicals and cell signaling molecules from entering the central nervous system and messing things up. Neurons and many of the cells that support neurons do not regenerate and tolerate stress as well as other parts of the body, which is why the BBB is so important. Through the various assays the primary authors used it seems like in the setting of long COVID there is a breakdown of the BBB—it starts letting things in and out that it shouldn’t be. This leads to inflammation and damage in the brain which likely results in immediate decreased processing ability and also long-term damage (which further leads to decreased processing ability). One of the components which “leaks” in this setting of BBB breakdown are components of the coagulation cascade (the things that make blood clot) which may potentiate small areas of clotting and decreased blood flow (a thing we called micro vascular ischemia—like an ischemic stroke but in very small capillaries). This entire mechanism is similar to (but very different in nuance) “leaky gut syndrome,” where the gut endothelium starts to break down and cause inflammation. I put that out there since leaky gut is gaining more popular understanding these days and may be more familiar for some folks.
As of now there is no available treatment that restores the endothelial integrity of the BBB. Off of the top of my head this study may suggest that more treatments to modulate the inflammsome (roughly—the amount of inflammation in your body) could be beneficial—which sort of tracks since there is some scattered evidence that high dose Omega-3’s help long COVID.