For years, researchers have worked to find out how they might be able to decrease or even halt the progression of Alzheimer’s disease, which currently has no cure and no long-term effective treatment. A new study shows, however, that the key to reducing memory loss issues may have been right in front of us all along.
Researchers at the University of Sussex wanted to know why the hippocampus in particular is so vulnerable to damage and degeneration when other parts of the brain often remain healthy. The hippocampus is often referred to as the brain’s memory center, because it is a part of the brain that is highly responsible for the forming and storage of memories.
The researchers theorized that blood oxygen level may have something to do with it and tested their theory by measuring the hippocampal blood oxygen levels, brain activity, and blood flow in mice.
Simulations showed the researchers that it’s highly likely that the amount of oxygen supplied to the hippocampal cells farthest from the blood vessels may be just enough to keep the cells working and not really enough for optimal functioning.
“We found that blood flow and oxygen levels in the hippocampus were lower than those in the visual cortex,” says Dr. Kira Shaw, a psychology researcher at the University of Sussex who undertook the main experiments. “Also, when neurons are active, there is a large increase in blood flow and oxygen levels in the visual cortex. This provides energy to hungry neurons. But in the hippocampus, these responses were much smaller.”
Dr. Catherine Hall, senior lecturer in psychology at the University of Sussex, describes the hippocampus’s tendency not to work optimally and how easily it falls into a state of dysfunction.
“We think that the hippocampus exists at a watershed. It’s just about OK normally, but when anything else happens to decrease brain blood flow, oxygen levels in the hippocampus reduce to levels that stop neurons working. We think that’s probably why Alzheimer’s disease first causes memory problems – because the early decrease in blood flow stops the hippocampus from working properly.”
The findings demonstrate that increasing blood flow and oxygenation to the brain could work wonders in terms of slowing or halting the progress of Alzheimer’s-related memory loss.
“If it’s right that increasing blood flow in the hippocampus is important in protecting the brain from diseases like Alzheimer’s, then it will throw further weight behind the importance of regular exercise and a low-cholesterol diet to long-term brain health,” says Dr. Hall.
“The same factors that put you at risk of having a heart attack make you more likely to develop dementia. That’s because our brains need enough blood flow to provide energy – in the form of oxygen and glucose – so brain cells can work properly, and because blood flow can clear away waste products such as the beta-amyloid proteins that build up in Alzheimer’s disease.”
The study also showed that the blood vessels of the hippocampus don’t contain as many mRNA transcripts for making the proteins that shape blood vessel dilation as other parts of the brain do. Additionally, the pericytes—the cells that dilate small blood vessels—were a different shape in the hippocampus. Each of these factors makes it difficult for the hippocampus to get enough blood and oxygen to its cells.
The scientists also found that blood vessels in the hippocampus contained fewer mRNA transcripts (codes for making proteins) for proteins that shape blood vessel dilation. Additionally, the cells that dilate small blood vessels, called pericytes, were a different shape in the hippocampus than in the visual cortex.
“We think blood vessels in the hippocampus are less able to dilate than in the visual cortex,” says Dr. Shaw.
“Now we want to discover whether the lower blood flow and oxygen levels in the hippocampus are what causes beta-amyloid to start to build up in Alzheimer’s disease,” says Dr. Hall. “Understanding what causes early damage will be really important to help us learn how to treat or prevent disease.”
It probably doesn’t come as a surprise to you that a low-cholesterol diet and plenty of exercise are essential parts of this equation, just like they’re essential to so many of our bodies’ healthy functions. But if you don’t want to have memory loss issues, that’s one more great reason to make sure you’re living the healthiest lifestyle you can.Whizzco