Does Alzheimer's start at 40?
A group of researchers from the University of Southern California in Los Angeles has proved that the destruction of pericytes - cells surrounding small blood vessels - leads to damage to the white matter of the brain and the development of dementia. These changes can begin as early as the age of 40.
White matter is brain tissue consisting of nerve fibers connecting neurons to each other or other cells of the body. The defeat of the white matter leads to the termination of the transmission of impulses along nerve fibers, memory, thinking and movement disorders develop.
In the first part of the study, the authors studied postmortem brain samples of people suffering from Alzheimer's disease and neurologically healthy people. The comparison showed that the number of pericytes in Alzheimer's disease is 50% less than in healthy people. The level of fibrinogen (a protein that normally circulates in the blood and does not penetrate into the brain tissue) in the white matter, on the contrary, was increased three times.
Next, an experiment was conducted on mice. Brain MRI of mouse models with pericyte deficiency helped to understand their role in brain health.
Mice with a deficiency of pericytes at the age of 12-16 weeks (this corresponds to 40 years in "human" time) had a tenfold increased level of fibrinogen in the corpus callosum – the part of the brain that provides the relationship of the right and left hemispheres. At the age of 36-48 weeks, equivalent to 70 years in humans, mice showed a 50% increase in vascular wall permeability. This proves that with a decrease in the number of pericytes, blood flow in the vessels of the brain is disrupted, and the blood-brain barrier does not work properly.
In the next part of the study, the motor functions of mice were evaluated using wheel testing. Mice with pericyte deficiency aged 12-16 weeks worked 50% slower compared to healthy mice.
MRI of the brain of mouse models with a deficiency of pericytes showed structural changes in the white matter.
The authors write that the results of the study suggest that people have changes in the brain, which then flow into Alzheimer's disease, begin at the age of 40.
The researchers used a drug that reduces the level of fibrinogen in the brain of mice. This led to the restoration of the structure of the white matter by 90%, its functions by 80%.
The authors believe that therapy aimed at reducing the level of fibrinogen has a huge potential for treating Alzheimer's disease long before the appearance of amyloid plaques and the development of clinical manifestations. Given that fibrinogen circulates in the blood and should not penetrate into the brain tissue, emphasis should also be placed on therapeutic enhancement of the blood-brain barrier, without waiting for the first clinical manifestations of Alzheimer's disease.
Article by Joanna Wardlaw et al. Neuroimaging standards for research into small vessel disease and its contribution to aging and neurodegeneration are published in the journal The Lancet Neurology.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru According to Medical News Today: Alzheimer's-related brain changes could start at 40.