An important paper from Füger et al last month, in which they labelled individual microglia in mouse brains and tracked their locations over 1.5 years. Here were some of their major findings:
- The median lifespan of microglia was estimated to be approximately 2.5 years, which is close to the mean lifespan of the mice that they were studying. So, it is fair to think of microglia as long-lived tissue macrophages. It is also clear how changes in microglia epigenetics in earlier life could affect late-life cognitive outcomes.
- Microglia died at a higher rate in older mice, suggesting that aging may lead to alterations in microglia function that could affect neurodegenerative disease.
- In APPPS1 mice, microglia proliferate 3x more than usual in areas of the cortex without amyloid plaque, but only proliferate a normal amount in areas of the cortex with amyloid plaque. This suggests that any increase in microglia near plaque is likely due to migration, not local proliferation.