Written on Tuesday, January 30, 2007 by Gemini
Washington: Mothers interfere with their children’s lives even more than most offspring realise. Mothers leave cells inside their children’s bodies, which help repairs when a child’s cells go awry. This form of maternal meddling is called microchimerism.
A mother’s cells can endure until a child reaches adulthood and perhaps throughout life. But scientists do not know exactly how common microchimerism is. It is detected more often in people with autoimmune conditions, which has led to the suggestion that the maternal cells could trigger those diseases. But healthy people have them too, with no ill effects.
Lee Nelson, of the University of Washington suspects everybody has maternal cells. Her recent work, argues that in some cases they help rather than harm. Her research consisted of two parts. In the first, Nelson took blood samples from three groups of young volunteers and their mothers. The first group comprised 94 volunteers who had diabetes; the second were 54 of their healthy siblings; and a further 24 were children without diabetes who were not related to anyone else in the study.
Because mothers pass copies of about half their genes to their children, some genes in any childmother pairs will be unique to the mother—those that the child has not inherited from her. Others—versions of genes that came from dad—will be unique to the child. Nelson used the uniquely maternal genes to find mothers’ cells in the volunteers’ blood. The technique found maternal cells in about half the diabetics’ samples, but in only about one-third of the healthy siblings’ samples and in less than one-fifth of those from the unrelated volunteers.
Moreover, the microchimerism was not only more common but also more pronounced in diabetics. Nelson found that diabetics with maternal cells tended to have more of them than did non-diabetics with maternal cells. Why? In the second half of the study, Nelson examined the pancreatic tissue of four dead boys, one of whom had been diabetic. Specialised cells within that tissue, called islet beta cells, make insulin. Usually, by the time diabetes is diagnosed most islet beta cells have stopped working.
She found female cells (from mother) in all four samples. Furthermore, these cells had transformed themselves into the insulin-producing islet beta cells. They also produced insulin, demonstrating mothers do indeed interfere at a cellular level. Nelson also looked for signs that maternal cells had caused the diabetes but found no evidence. So, she believes maternal cells can do children good—and that there is no reason to think they do so only in the pancreas. These cells may help any bodily organ work better, she says, apart from the reproductive kind.