During pregnancy, part of thegenetic material from the fetus passes into the mother’s bloodand it can stay there for many years. A study published in the journalPLoS ONEindicates that women with DNA fragments from their male children in their brains are less likely to have Alzheimer’s disease.
According to experts, the exchange of DNA and cells between mother and child can have positive and negative effects: on the one hand, the cells could be beneficial for maternal health, since they promoterepair damaged tissues and improve defenses;but they can also cause problems, such as an autoimmune reaction, which occurs when the immune system acts against its own elements.
Another question is the effect of fetal cells in the brain. Previous studies have detected its presence in the brains of mice, but not in humans. In this study, the researchers, from the Seattle Cancer Research Center (USA), collected brain samples from 59 dead women between the ages of 32 and 101, and found remains of the Y chromosome – exclusive to males – in the 63 percent of them. In addition, half of the women studied had had symptoms of Alzheimer’s, and they carried a lot ofless male genetic material in their brainsthan women who had not had the disease.
Does this mean that having male children protects their mothers from neurodegenerative diseases such as Alzheimer’s? “We honestly don’t know,” explains J. Lee Nelson, one of the study’s authors. Scientists often find correlated data, and this does not mean that one is the cause of the other. On the other hand,male DNA is easier to detect in the motherthan that of daughters, since women do not have a Y chromosome, so it would also be necessary to analyze whether the fetal DNA of daughters has the same effects as that of boys.
“Previous work showed that, in mice, cells from the fetus can migrate from the mother’s brain, and once there mature into neurons, but we have yet to see if this happens in humans, and what effects it has.” adds the author, whose work is undoubtedly a first step in the study of the consequences of DNA exchange between mothers and children.
