Implantation of islets of Langerhans, generated in vitro using stem cell technology, reverses insulin-dependent diabetes in mice, US researchers report. This method of islet cell production could provide "a source for generating functionally useful islets," they say. The implanted cells were not rejected via autoimmune responses (Nature Medicine 2000;6:278).
Dr Ammon Peck (department of pathology, immunology and laboratory medicine, University of Florida college of medicine) and colleagues grew cultures of islet-producing stem cells (IPSCs) obtained from pancreatic ducts of adult non-obese diabetic (NOD) mice who were in a pre-diabetic state. From the IPSCs, islet progenitor cells (IPCs) budded, which proliferated into islet-like structures.
Islets derived from the IPCs were then implanted into a kidney in eight diabetic NOD mice. Five days after transplantation, the mice were weaned from the insulin on which they had been maintained. A decrease in blood glucose was shown after one week. The mice remained healthy and did not require insulin therapy for up to 55 days. The researchers conclude that "implanted, IPC-derived islets could provide adequate insulin to maintain stable blood glucose levels over the time of the experiment."
In an accompanying editorial (ibid, p250), Dr David Sachs (Joslin Diabetes Centre, Boston, Massachusetts) says that transplantation of the whole pancreas, while successful, has too many potential complications for a condition such as diabetes, which can be treated with insulin. If islet cell transplantation were as successful as whole pancreas transplantation, "it would quickly become the treatment of choice for many diabetics," he says. A potential problem of islet transplantation, so far, has been obtaining large enough numbers of purified islets, a problem which Dr Peck and his colleagues might have overcome with the use of stem cell technology.
Dr Sachs comments: "One reason this report is exciting is that, although the islet cultures were derived from pre-diabetic NOD mice, the recipients of these islets seemed not to develop subsequent diabetes. Translated to a clinical situation, this would represent the ability to culture relatively unlimited numbers of islet cells from a piece of the pancreas of an early diabetic individual, and produce sufficient islets to reinfuse later as a treatment for diabetes."