SEATTLE For the first time, scientists have discovered that cells passed from mother to child during pregnancy can differentiate into functioning islet beta cells that produce insulin in the child. The same study also found that maternal DNA was found in greater amounts in the blood of children and young adults with Type 1 diabetes than their healthy siblings and a control group, implying that they may be attempting to repair damaged tissue.
The findings suggest a beneficial role for this type of maternal microchimerism. Microchimerism is the term used when an individual harbors cells or DNA that originate from another genetically distinct individual.
In this study, published in the Jan. 22 issue of the Proceedings of the National Academy of Sciences, J. Lee Nelson, M.D., a member of the Clinical Research Division at Fred Hutchinson Cancer Research Center, and colleagues found no evidence that the mother's cells were attacking the child's insulin cells and no evidence that the maternal cells were targets of an immune response from the child's immune system.
"We think the maternal cells may be helping to regenerate damaged tissue in the pancreas," Nelson said.
She said investigators are excited about new possible approaches to treat Type 1 diabetes raised by their findings. For example, if maternal microchimerism results in cells that make insulin, a mother's stem cells might be harvested and used to treat her diabetic child. Such cells would have a genetic edge over donated islet cells from a cadaver that are usually completely genetically mismatched.
"The child is probably tolerant to the mother's half-matched cells because the child acquired the cells during its life as a fetus while its immune system was still developing," Nelson said.
Originally, the study of 172 individuals and pancreatic tissue from four males was designed to ask the question whether these small numbers of maternal cells might be involved in any way in Typ
Contact: Dean Forbes
Fred Hutchinson Cancer Research Center