The biggest genetic risk factor for Alzheimer’s disease appears to lead to fat droplets accumulating in brain immune cells, highlighting a possible cause of the condition that has been overlooked
By Clare Wilson
13 March 2024
Various changes are seen in the brains of people with Alzheimer’s, but the exact cause of the disease is unclear
Science Photo Library/Alamy
A new understanding of Alzheimer’s disease suggests that the root cause involves a build-up of fat droplets in brain cells.
Targeting these droplets could lead to more effective treatments than the current strategy of drugs that target proteins, says Michael Haney at the University of Pennsylvania. “This opens up a new avenue for therapeutic development,” he says.
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The commonest explanation for Alzheimer’s disease is that it is caused by a build-up of a protein called beta-amyloid in plaques between nerve cells. Another suspect is a build-up of tangles made of a different protein, called tau, stored inside nerve cells.
Arguments over which of these two proteins is the key culprit have gone on for decades. The amyloid hypothesis is currently in the lead, as some antibody treatments that rid the brain of it have recently shown modest effectiveness at slowing memory loss in people with Alzheimer’s.
But this debate ignores the fact that fat droplets can also be seen in the brains of people who have died from the disease, says Haney. These were first described by Alois Alzheimer, a German doctor who gave his name to the condition in the early 20th century, when he noted amyloid plaques, tau tangles and fat droplets present in the brains of people who had Alzheimer’s. But for decades the fat was mostly overlooked.