The term frontotemporal dementia (sometimes called Pick’s disease) refers to a number of related dementias that involve nerve cell loss in the frontal or temporal lobes of the brain. Frontotemporal dementia can be especially challenging for caregivers. It is often marked by significant changes in a loved one’s personality, behavior, muscle control, and ability to master language. Alterations in personality and behavior are common. A new study suggests that frontotemporal dementia may be triggered by a defect in certain immune cells.
Published by the medical journal, Cell, the study is entitled “Progranulin Deficiency Promotes Circuit-Specific Synaptic Pruning by Microglia via Complement Activation.” (Click here to read about the study.) The study is preclinical, meaning that it does not look at the disorder in humans; rather, it studies how the disorder is presented in an animal model, in this instance in mice.
Previous studies have indicated that the immune system plays a role in many neurodegenerative disorders. This study adds frontotemporal dementia to that list.
In this instance, researchers were looking at immune cells called microglia. These cells are part of the process that takes viruses, bacteria, and dead brain cells and disposes of them. They also “prune” unneeded neural connections.
The scientists determined that, in mouse models of frontotemporal dementia, microglia were too aggressive in getting rid of these connections, often mistakenly targeting connections that shouldn’t have been disconnected. By going overboard in this area, microglia trigger development of frontotemporal dementia.
By making genetic alterations in mice, scientists were able to correct the situation. Now the question is whether such a result is possible in humans – but that is likely a question that will not be answered for some time.
Still, it is valuable to have this information so that scientists can develop strategies that may lead to a treatment for frontotemporal dementia in humans down the road.