A report in Science published on World Diabetes Day (14th November 2003) has brought new hope to diabetes sufferers by showing that spleen cells can be used to cure type 1 diabetes in mice — injected spleen cells differentiated into insulin-producing cells in diabetic animals.

Islet cells of the pancreas secrete insulin, which is needed to remove excess glucose from the blood. But in type 1 diabetes, the immune system destroys the islet cells and high sugar levels in the blood cause serious medical complications. Denise Faustman and colleagues, from Massachusetts General Hospital (MGH), injected donor spleen cells from normal mice into diabetic mice and found, surprisingly, that they produce normal insulin-secreting islet cells. According to Faustman “The unanswered question from that study was whether this was an example of rescuing a few remaining islet cells in the diabetic mice or of regeneration of the insulin-secreting islets from another source” (ScienceDaily, 17 November 2003).

In an elegant set of experiments using labelled donor spleen cells, Faustman and colleagues now show that, in fact, the insulin-producing cells grow from both the recipient's own cells and the donor cells. “We have found that it is possible to rapidly regrow islets from adult precursor cells, something that many thought could not be done” said Faustman (ScienceDaily, 17 November 2003). David Nathan, Director of the MGH Diabetes Center, believes that using this procedure “Patients with fully established diabetes possibly could have their diabetes reversed” (BBC News Online, 14 November 2003), and hopes to test the approach in clinical trials.