The way energy is distributed throughout the body is by blood. It provides oxygen and nutrients to different parts of the body, including brain. Previous studies have shown that the first change in Alzheimer’s disease is a decrease in cerebral blood flow. Now scientists from UCL confirmed that reduced blood flow to the brain associated with early Alzheimer’s may be caused by the contraction of cells.
Red and yellow areas in these scans are showing high concentrations high amounts of amyloid deposits in the brain. Image credit: Klunkwe via Wikimedia (CC BY-SA 3.0)
Glucose and oxygen supply to the brain, taken care of by the blood flow, is very important. It allows for cells to grow and regenerate. Without efficient blood supply, it is not possible to have a healthy brain or any other organ for that matter. Pericytes, cells wrapped around capillaries, are able to contract to regulate the blood flow. Pericytes help the body regulating the temperature and blood pressure. Scientists decided to see how pericytes behave in people with Alzheimer’s disease and found that pericytes are squeezing capillaries in Alzheimer’s-affected brain tissue.
Tests were also carried out with specially bred mice that developed Alzheimer’s pathology. Scientists found that the blood flow is cut in half and it corresponds with the decrease in blood flow found in parts of the brain affected by Alzheimer’s. Reduced blood flow is the first clinically detectable sign of Alzheimer’s, but the mechanism was largely unknown up until now. Scientists say that results of this research could lead to new treatments that would fix these symptoms and potentially improve the health of the brain affected by the Alzheimer’s. Scientists also found that amyloid beta protein, which accumulates in the brains of people with Alzheimer’s, is probably responsible for the squeezing of the blood vessels.
Scientists say that at least part of the damage, seen in the brain of someone with Alzheimer’s, can be explained through the loss of energy supply. This opens up new opportunities for a new generation of Alzheimer’s medicine. Professor David Attwell, senior author of the study, said: “In clinical trials, drugs that clear amyloid beta from the brain have not succeeded in slowing mental decline at a relatively late phase of the disease. We now have a new avenue for therapies intervening at an earlier stage”.
Combating reduced blood would mean fighting a symptom. However, it is a very important symptom and reducing its effects could have a huge positive influence on the progression of the disease. Now scientists have to accelerate their research and see how they can take advantage of this newly acquired knowledge.
Source: UCL