A new study from Northwestern’s Feinberg School of Medicine has provided insight into the cause of Alzheimer’s disease.
Focusing on sporadic Alzheimer’s disease, the study revealed that a slow, long-term deficiency of glucose and oxygen to the brain may provide a link to what triggers the disease, said Robert Vassar, a professor at Feinberg who conducted the research.
The disease, mainly observed in senior citizens, is responsible for the rapid deterioration of a number of cognitive abilities. About 26.6 million people suffered from Alzheimer’s worldwide in 2006.
“We don’t understand the cause of SAD, only that it is related to age,” said Vassar, who specializes in cell and molecular biology.
The experiment sought to investigate how the aging process may be linked to the onset of sticky, fiber-like clumps of proteins known as amyloid plaques that are responsible for brain cell death.
Naturally, blood flow decreases to the brain as people age, which, over time, starves the brain of the oxygen and glucose needed for it to perform properly, Vassar said. This deprivation of glucose, a sugar that is the principal source of energy for most living things, initiates a biochemical response to offset the stress experienced by brain cells.
This deprivation, however, is “not enough to cause injury, but is enough to make the cells stressed out,” Vassar said.
During these periods of stress, brain cells secrete an enzyme known as BACE1 as a defensive mechanism, but the process generates a protein that could lead to plaque formation later in life.
“The enzyme BACE helps cells survive temporary stress,” Vassar said. “For short-term, acute stress, BACE is good, but for the long-term, things go awry.”
Vassar’s experiment involved studying the biochemical mechanisms that took place in the kidney cells of a genetically engineered mouse and in other cell cultures. The results showed elevated BACE1 levels when the supply of glucose to the cells was limited, Vassar said.
An individual’s susceptibility to developing Alzheimer’s generally increases with age, but there are a number of preventative measures that can be taken to delay the onset of AD, Vassar stressed. Maintaining a healthy diet and cardiovascular exercise regimen during mid-life can help prevent diseases that limit blood flow to the brain, such as atherosclerosis or hardening of the arteries, and hypertension.
“People need to understand how important their cardiovascular strength is – exercise, dieting, and a healthy change in lifestyle will have the benefit of keeping Alzheimer’s at bay,” said Vassar. “What’s good for the heart is good for the brain.”
