Link Between Alzheimer’s and Leaky Blood-Brain Barrier Identified
The blood-brain barrier limits entry of blood-derived products, pathogens, and cells into the brain. A recent study suggests that the brain’s protective blood barrier may start leaking as people age. The leaks appear to start in the hippocampus, which is an important critical learning and memory center that is damaged in people with Alzheimer’s disease.
For the first time ever, researchers examined live human brains in 64 people of a variety of ages using high-resolution imaging. They found that even normally aging brains had leakage around the hippocampus, which normally has the highest barrier when compared to other parts of the brain. They also noted more damage in the hippocampus in people with dementia than in people who did not have dementia.
The researchers also examined the particiapants cerebrospinal fluid, which flows through the brain and spinal cord. Those who showed mild signs of dementia had 30% more albumin, a blood protein, in their cerebrospinal fluid than those with no signs of dementia. This provides further evidence of a leaky blood-brain barrier.
The cerebrospinal fluid of the participants with dementia also had a 115% increase in a protein related to pericyte injury. Pericytes are cells that surround blood vessels and help maintain the blood brain barrier; previous research has linked pericytes to dementia and aging.
In order to validate their methodology, the researchers also looked at brain scans of young people with multiple sclerosis but no cognitive impairment, and compared them to young people with neither multiple sclerosis nor cognitive impairment. They did not find any difference in the blood-brain barriers of the hippocampus’ of people of the same age who had the disease and those who did not. They did find, however, increased blood-brain permeability in the white matter of those with multiple sclerosis.
The researchers hypothesized that in order to prevent dementias such as Alzheimer’s in the future, they may need to figure out how to maintain the intergrity of the blood-brain barrier in order to prevent the brain from being flooded with toxic chemicals in the blood.
Researchers from the University of Southern California conducted the study. It was published in the January 2015 issue of Neuron.
Previous studies suggest that vitamin B12, aloe vera, omega-3s, and vitamin E supplements may also slow the progression of Alzheimer’s, which has no cure and had no known cause up until this study was published.