Maternal DNA could help prevent diabetesStem cells could be harvested to treat child

23 January 2007

Cells passed from mother to child during pregnancy could be used to treat insulin-dependent diabetes, new research suggests.

Scientists found they can develop into functioning islet beta cells which produce insulin in the pancreas.

They think in some cases the maternal cells may protect against the kind of damage that leads to type 1 diabetes.

The discovery opens up the future possibility of a mother's stem cells being harvested and used to treat her diabetic child.

Essential hormone

Type 1 diabetes is an autoimmune disorder which destroys insulin-producing pancreatic cells.

Insulin is the essential hormone used by the body to regulate the uptake of glucose for energy production.

Around 350,000 people in the UK suffer from type 1 diabetes and have to give themselves regular insulin injections.

The new findings suggest an unusual and beneficial form of "microchimerism", the harbouring of cells or DNA that originate from another genetically distinct individual.

Originally, the research was carried out to investigate whether cells passing from mother to child in the womb were in some way responsible for type 1 diabetes.

Maternal cells

Scientists studied 172 individuals and took pancreatic tissue from four deceased males.

They found small numbers of female islet beta cells in the pancreatic samples that were capable of producing insulin.

There was no evidence that the mother's cells were causing damage or becoming the target of an immune response.

However the researchers found more maternal DNA in the blood of children and young adults with type 1 diabetes than in healthy individuals.

Although the disease was not prevented, it looked as if the mother's cells were trying to undertake repairs.

Regenerating tissue

"We think the maternal cells may be helping to regenerate tissue in the pancreas," said Dr Lee Nelson, one of the investigators from the Fred Hutchinson Cancer Research Center in Seattle, US.

"The child is probably tolerant to the mother's half-matched cells because the child acquired the cells during its life as a foetus while its immune system was still developing."

Maternal microchimerism was first recognised in children with severe immunodeficiency in the 1970s.

In 1999, Dr Nelson showed that microchimerism can persist into adulthood in people with normal immune systems.

Writing in the journal Proceedings of the National Academy of Sciences, the researchers said they believed the new findings were the first to describe a maternal contribution to hormone function.

They added: "Our findings also raise the possibility that naturally acquired microchimerism might be exploited to therapeutic benefit."

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