Using Magnetic Resonance Imaging, researchers in the Netherlands have found what they believe to be a connection between a leaky blood brain barrier (BBB) and Alzheimer’s disease.  According to their report published in the journal Radiology a team of investigators led by Harm J. van de Haar saw a significantly higher rate of leakage in the BBB in people who had early symptoms of Alzheimer’s disease than in normal, healthy adults.

Just what is the blood brain barrier?

The blood brain barrier is responsible for keeping toxins in the blood stream from infecting the brain. A leaky blood brain barrier may be responsible, at least in part, for the onset of Alzheimer’s disease. Credit University of Washington

The blood brain barrier is, as the name implies, a membrane that separates the blood in the circulatory system from the fluid that surrounds the brain cells. Its purpose is to filter out possible neurotoxins, including bacteria, contained in the blood. At the same time it allows to pass those nutrients that are essential to normal neurological function. Because of this selective screening system infections of the brain are rare. Conversely, when they do occur they can be extremely difficult to treat. The barrier also blocks many drugs from entering the brain from the bloodstream, including most antibiotics.

In cases like this it is important to consider the direction of cause and effect. Does the leaky blood brain barrier cause Alzheimer’s disease or result from it. By adding analysis of some vascular diseases like diabetes to the mix the study concluded that the permeable BBB likely created the conditions for dementia.

The authors list two important generalizations that can be taken away from their findings:

1. Patients with early Alzheimer disease have significantly more tissue characterized by blood-brain barrier leakage than do healthy control subjects, both in the normal-appearing white matter (P = .019) and in the gray matter (P = .004).
2. Blood-brain barrier leakage in the gray matter correlates with lower scores on the Mini-Mental State Examination¹.

The test group in this study was small, which limits its impact. The authors, on the other hand, feel that the differences between the test group and the control group were significant enough to warrant further study. If further study substantiates this teams findings it may lead to an accurate early diagnostic tool. Early diagnosis can provide a powerful tool in our search for a cure because researchers will be able to look at disease as it is taking hold. It will also give the individual diagnosed an opportunity to participate in the planning of their future.

Related Research: leaky blood brain barrier and Alzheimer’s

1. Mini–mental state examination; From Wikipedia, the free encyclopedia
2. Erickson MA, Banks WA. Blood-brain barrier dysfunction as a cause and consequence of Alzheimer’s disease. J Cereb Blood Flow Metab 2013;33(10):1500–1513.
3. Montagne A, Barnes SR, Sweeney MD, et al. Blood-brain barrier breakdown in the aging human hippocampus. Neuron2015;85(2):296–302. CrossRef,