The human brain is an extremely sensitive organ. Therefore, it must also be particularly protected from toxins and pathogens. The supply of messenger substances and the removal of metabolic products must also be precisely regulated. The blood-brain barrier (BBB) has exactly this function and separates the central nervous system from the rest of the body’s blood circulation. The BBB acts as a shield, protecting the brain from infectious agents and toxic substances, but must also act as a filter, allowing nutrients to get inside the central nervous system.
Recent studies have shown that this thin structure plays an important role in Alzheimer’s disease. In fact, it seems to be involved in the process of the disease even before the first pathological changes are identified. You can have further information about the relationship of ApoE4 and BBB breakdown in the article published in our previous news feed “Alzheimer gene triggers early collapse of the blood-brain barrier and predicts cognitive decline”.
Besides genetics, other factors can contribute to the linkage of the BBB and lead to or perpetuate the cascade of inflammation and neurodegeneration observed in Alzheimer’s disease. Of all the factors that can cause the blood-brain barrier to break down, the alteration of intestinal permeability is given greater consideration because it is a modifiable factor depending on lifestyle measures. Diet composition and gut microbiota play a crucial role in maintaining intestinal integrity and the intestinal-brain axis. On the subject of the ‘gut-brain axis’, why not take a look at our fact sheet, which “Knowledge stops Dementia”’ makes available to you free of charge.
The importance of the composition of the microbiota becomes clear in the following: specific substances produced by gut bacteria can influence BBB barrier permeability: So-called lipopolysaccharides are endotoxins and pro-inflammatory agents produced by gram-negative bacteria that can potently stimulate BBB disruption. On the other hand, short-chain fatty acids produced by commensal bacteria can protect the BBB from damage.
In order to bring you more information about this important structure of the nervous system, we have updated the Brain & Body section of the KsD page, adding a review about how the BBB breakdown plays an important role in the accumulation of Alzheimer-specific plaques in the form of amyloid-beta. You will find the complete update in the Brain & Body section – Blood Brain Barrier.
Figure 1: Physiopathological cycle of Blood-brain-barrier (BBB) injury and Amyloid beta (Aβ) accumulation in Alzheimer’s disease
You will be able to understand which factors can contribute to disrupting the BBB and the close relationship between gut permeability and BBB breakdown, and especially, how important a healthy lifestyle is for your mental health!
Enjoy your reading!
Link to Brain & Body section here.