Grant: CIHR Fellowship

Naturally acquired microchimerism refers to the acquisition of a small number of genetically distinct cells or DNA through pregnancy. During pregnancy, mother and fetus constantly exchange materials (nutrients, gases and waste products) with each other via the placenta. Recently, exchanges of cells and/or DNA have also been detected. Surprisingly, many years after their physical union is severed, maternal microchimerism can be found in her adult offspring and fetal microchimerism in the mother. These recent findings challenge the traditional view of self and point to the potential for both good and bad consequences for human health. In humans, maternal and fetal microchimerism has been identified in blood, heart, kidney, pancreas and spleen. No prior study has tested the brain. That human brain is likely to include microchimerism is supported by recent experimental studies that found fetal and maternal microchimerism in mouse brain. Therefore, the overall goal of this project is for the first time to identify, quantify and characterize microchimerism in the human brain, particularly fetal microchimerism in women. Once the prevalence, quantity and phenotype of microchimerism have been established, we may extend our studies to selective brain diseases. Effects of microchimerism in the brain could either be beneficial (tissue repair, tumor immune surveillance or normal development) or adverse (targets of immune attack, accessory to degenerative changes or neoplasia). As there is currently no information regarding naturally acquired microchimerism in the human brain, this project will be the first to explore this new frontier and provide a useful basis of knowledge for future studies of normal development of the brain (including aging) and specific brain diseases.