For the first time scientists have used cells from a woman with type 1 diabetes to create cloned human embryos from which they extracted embryonic stem cells.
The American-Israeli team also coaxed the stem cells into insulin-producing beta cells, the kind lost in patients with type 1 diabetes.
"These stem cells could therefore be used to generate cells for therapeutic cell replacement," research leader Dieter Egli, from the New York Stem Cell Foundation Research Institute, said.
Embryonic stem cells are capable of transforming into any tissue in the body, not just insulin-producing cells. Therein lies their medical potential – to regenerate tissue or organs for transplant.
The benefit of stem cells obtained from cloned human embryos is they are genetically matched to the person who donated the adult cell, meaning they could be used to personalise therapies for a range of crippling diseases, not just diabetes.
But somatic cell nuclear transfer – the technique used to create Dolly the sheep – is ethically controversial in humans because it involves the creation of embryos for research that are subsequently destroyed.
To obtain stem cells from the cloned human embryo, the nucleus of a skin cell from the woman with type 1 diabetes was transferred into a donated human egg, which had had its nucleus removed.
The cells grew into early-stage embryos, or blastocysts, that gave rise to human embryonic stem cells. The researchers published their findings
in the journal Nature.