Human blood cells coaxed to produce insulin

时间:2019-03-02 12:19:00166网络整理admin

By Andy Coghlan Tantalising experiments that seem to have made human blood cells start producing insulin have raised the prospect of a new treatment for diabetes. Although the treatment has only been tried in mice so far, it might mean people can be cured with implants of their own cells. But even the researcher whose team carried out the work says he will remain sceptical until other groups have repeated it. “If it’s true, it would be very nice, but the data is very preliminary,” cautions Bernat Soria, chairman of the European Stem Cell Network. Juvenile-onset diabetes is caused by the immune system destroying the insulin-producing beta cells in the pancreas. It can now be treated by transplanting beta cells taken from cadavers, using a technique called the Edmonton protocol. But many recipients suffer severe side effects because of the drugs they have to take to prevent their immune systems rejecting the foreign cells. Also, the supply of beta cells is limited – only 500 people have been treated so far. Several teams around the world have now managed to derive insulin-producing cells from human embryonic stem cells (ESCs). While this might one day end the shortage of beta cells for transplantation, it is not a perfect solution. One problem is that there is no easy way to derive ESCs from individual patients, so obtaining matching cells might not be possible and immunosuppressant drugs would likely still be needed. And even if the beta cells were a perfect match, without drugs they might still be destroyed by the same autoimmune reaction that killed patients’ original beta cells. Soria’s team at the Institute of Bioengineering in Alicante, Spain, was the first to obtain insulin-producing cells from mouse ESCs and is also working with human ESCs. Recently, together with Fred Fandrich of the University of Kiel in Germany, the team tried a different approach: exposing human white blood cells to the same growth factors it had applied to mouse ESCs. It worked. “We convinced white blood cells to produce insulin,” Soria says. When the transformed cells were injected into diabetic mice, their blood sugar levels returned to normal, Soria told a recent conference on stem cells in Edinburgh, UK. After a week the effect disappeared, because the animals’ immune systems destroyed the human cells. The full results will appear soon in Gastroenterology. The next step is to find out if insulin-producing cells can be derived from the blood of people with diabetes, and if they will be stable after re-implantation. One great advantage of the approach, if it works, is that white blood cells are very easy to obtain. It is not yet clear whether the insulin-producing cells have actually become beta cells or another cell type that has been persuaded to make insulin, says Chris Burns of King’s College London, who studies beta cells. This should not matter as long as the cells produce normal insulin in response to rising blood sugar levels, he says. “If this is the case, then this would be a significant advance.” It could even be an advantage if the cells are not true beta cells, as it means they might escape the autoimmune reaction that causes juvenile diabetes. More on these topics: