Study Disturbed fat breakdown in the brain leads to measurable dumbing down

Disturbed fat loss in the brain makes mice dumb
Impaired fat loss in the brain has an extremely detrimental effect on learning and memory performance, according to a recent study led by scientists at the University of Bonn. The study results also throw a new look at the development of dementia, reports University.

Due to the disturbed degradation of certain fat molecules in the brain, according to the researchers, the learning and memory performance is significantly impaired - at least in mice. In model experiments, the animals showed significantly worse learning and memory performance in impaired fat loss. In addition, the amount of Alzheimer-specific proteins has risen sharply in their brains, the scientists report. The researchers published their results in the journal "Autophagy".

A disturbed fat loss in the brain has far-reaching consequences and could be involved in the development of dementia. (Image: denisismagilov / fotolia.com)

Brain fat really exists
In the experiments, the scientists in the brain of mice prevented the breakdown of a specific fat molecule. Because the proverbial "brain lard" is, according to the researchers actually. Thus, apart from water, the brain mainly consists of lipids, in other words: fat. These lipids serve, for example, "as an insulating layer around the nerve fibers and thus prevent short circuits," explain the experts. In addition, they are a major component of the thin membranous membranes surrounding the brain cells.

Mice learn and remember worse
One of the most common lipids in our brain is the so-called sphingolipid, whose degradation product S1P may play a central role in the development of Alzheimer's and other dementias, the researchers explain. For their experiments, they bred mice, "which can not further degrade S1P in large parts of their brains," said the Dr. med. Gerhild van Echten-Deckert of LIMES-Institut at the University of Bonn. As a result, "the animals learned much worse and could not remember so well," the university continues.

Mechanism of autophagy disturbed
According to the researchers, the S1P is normally broken down into several parts, with one of the breakdown products urgently needed for another metabolic pathway - the so-called autophagy. This mechanism allows cells to digest and recycle their own constituents. In this way, the cells can, for example, eliminate defective proteins or cell organelles that no longer fulfill their task.

Decomposition product of S1P needed for autophagy
According to the scientists, the intracellular waste disposal of autophagy works in two steps. First, the "garbage" is packed in tiny "garbage bags" that then fuse with other "bags" containing highly reactive enzymes. These enzymes then "shred" the contents of the garbage bags and dispose of them, explain the researchers. The packaging of the waste in the intracellular garbage bags involves a decomposition product of S1P and "without degradation of S1P form less closed garbage bags; the autophagy then does not work properly, "said study author Daniel Mitroi in the press release of the University of Bonn.

Accumulation of harmful substances in the brain
In the brain of mice, harmful substances have accumulated when S1P degradation is eliminated, such as "the protein APP, which plays a key role in the development of Alzheimer's disease," reports the lead author of the study.

Unknown mechanism of dementia discovered?
According to the researchers, the current study results put a focus on a hitherto completely unnoticed development mechanism for dementia. For the first time, the scientists from the University of Bonn, the University Hospital Jena, the German Center for Neurodegenerative Diseases (DZNE), as well as from San Francisco and Madrid, have shown the far-reaching consequences of disturbed S1P degradation. "Maybe our work will contribute in the long term to the fact that these disorders of the brain can be successfully treated at some point in the future," Dr. van Echten-Deckert. (Fp)