Filmmaker James Cameron proclaimed that he had opened a “new frontier” when he reached the Mariana Trench’s Challenger Deep last month, 200 miles below the surface of the ocean. Quietly and with less fanfare, California researchers have unlocked an important discovery about the human frontier of the brain, detecting new information about how dementia spreads.
Scientists at the University of California, San Francisco concluded that Alzheimer’s disease, as well as other forms of dementia, may move directly between connected neurons in the brain. The degree of connectedness between a nerve region in the brain and a disease “hot spot,” or epicenter, appears to have the strongest influence on how the degeneration of neurons occurs in people with dementia.
Previous theories about how dementia spreads have examined the role of “wear and tear” on areas of the brain that carry heavy signaling traffic, as well as breakdowns in brain connectivity that interrupt transport of growth factor needed to maintain brain neurons. Additional studies on the spread of dementia have looked at the role of specific genes or proteins that make certain networks in the brain more susceptible to disease. The UCSF findings suggest that the linked nerve cells are the strongest predictor of how dementia will spread from a point of origin in the brain to other areas.
The findings, published in the journal Neuron, may yield important information that will allow physicians to predict the course of dementias and potentially measure the effectiveness of treatment. This could be particularly significant in testing new medications to combat dementia, as brain network models combined with MRI imaging may produce information about how a drug works before dementia-related changes in behavior are apparent.
William Seeley, M.D., a neurologist and MacArthur Foundation “genius award” recipient from the UCSF Memory and Aging Center, led the research. In the study, Seeley and colleagues created what he calls a “wiring diagram” based on the brains of 12 healthy individuals using MRI imaging. Then they compared these “brain maps” with data on patients with five different forms of dementia, including Alzheimer’s disease and frontotemporal dementia, or FTD. Their analysis revealed that the trans-neuronal spread mechanism most closely matched the data in predicting how the disease-related proteins would spread.
An estimated 5.4 million people currently have Alzheimer’s disease, according to the Alzheimer’s Association. The number is expected to skyrocket as baby boomers age. In California, the projection for the number of people with Alzheimer’s by 2025 is 660,000, according to an Alzheimer’s Association report. This projected number marks a startling 50 percent increase since 2000, underscoring the need for research aimed at understanding, preventing, and curing the disease.
The degenerative effects of Alzheimer’s rob people of their memory and personality. The estimated 14.9 million family members and friends who care for Alzheimer’s patients often develop health problems related to the stress and exhaustion that go along with providing care.
“Every bit of new research is a critical piece of the much larger puzzle that will lead us to effective treatments and ultimately to a cure for this devastating disease,” said Jim McAleer, president and CEO of the Alzheimer’s Association, Orange County Chapter.
The Alzheimer’s Association Helpline is available 24 hours a day, seven days a week at 800-272-3900.