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 children and young adults with type 1 diabetes had higher levels of maternal DNA in their blood than their healthy siblings and a control group. This implies that their bodies may be attempting to repair damaged tissue. Maternal microchimerism
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 the study, published in the Jan. 22 issue of the journal Proceedings of the National Academy of Sciences, the Clinical Research Division's Dr. Lee Nelson 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.
Grants from the National Institutes of Health, the Juvenile Diabetes Research Foundation, the Iacocca Foundation and the Wellcome Trust funded this study.
To learn more, visit www.pnas.org/cgi/content/abstract/0606169104v1.