Alzheimer's-Related Brain Changes Could Start at 40

A study published in Nature Medicine details how damage to cells called pericytes can induce white matter disease associated with dementia, and the findings suggest these brain changes may happen as early as the age of 40, reports Medical News Today . The University of Southern California's Berislav Zlokovic notes white matter disease is common in older adults, and research has connected it to cerebral small vessel disease, which "contributes to almost 50 percent of dementia cases worldwide, including Alzheimer's disease." In the first stage of the study, the researchers conducted a postmortem analysis of the brains of people who had Alzheimer's, comparing them to the brains of healthy adults. The brains of people with Alzheimer's had half the number of pericytes as healthy brains, and levels of the protein called fibrinogen were three times higher in white matter regions. The team found 12- to 16-week-old mice with pericyte deficiency had levels of fibrinogen about 10 times higher in the corpus callosum, while at 36 to 48 weeks old the mice exhibited a 50 percent increase in blood vessel leakage. The team evaluated the mice's running speed, and pericyte-deficient mice ran 50 percent slower than control mice when they were 12 to 16 weeks old. "The mice deficient in pericytes function slower because there are structural changes in their white matter and a loss of connectivity among neurons," Zlokovic says. The researchers think these results may suggest fibrinogen as a target for preventing this dementia precursor.