Just kind of interesting. It's been suspected for a long time but I'm not sure if it was ever really demonstrated: Restoring via decal transplant was also interesting.
Gut microbiota influences blood-brain barrier permeability:ki.se/en/news/gut-microbiota-influences-blood-brain-barrier-permeability
"A new study in mice, conducted by researchers at Sweden’s Karolinska Institutet together with colleagues in Singapore and the United States, shows that our natural gut-residing microbes can influence the integrity of the blood-brain barrier, which protects the brain from harmful substances in the blood. According to the authors, the findings provide experimental evidence that our indigenous microbes contribute to the mechanism that closes the blood-brain barrier before birth. The results also support previous observations that gut microbiota can impact brain development and function."
I wonder if in normal healthy mice that undergo say antibiotics or have some sort of dysbiosis (DDS colitis) or something also experience an increase in permeability of their Blood Brain Barrier.