Last week, two people with type 1 diabetes became the first to receive implants containing cells generated from embryonic stem cells to treat their condition. The hope is that when blood sugar levels rise, the implants will release insulin to restore them to normal.
About 10 per cent of the 422 million people who have diabetes worldwide have type 1 diabetes, which is caused by the body’s immune system mistakenly attacking cells in the pancreas that make insulin. For more than 15 years, researchers have been trying to find a way to use stem cells to replace these, but there have been several hurdles – not least, how to get the cells to work in the body.
Viacyte, a company in San Diego, California, is trying a way to get round this. The firm’s credit-card-sized implant, called PEC-Direct, contain cells derived from stem cells that can mature inside the body into the specialised islet cells that get destroyed in type 1 diabetes.
The implant sits just below the skin, in the forearm, for example, and is intended to automatically compensate for the missing islet cells, releasing insulin when blood sugar levels get too high. “If it works, we would call it a functional cure,” says Paul Laikind, of Viacyte. “It’s not truly a cure because we wouldn’t address the autoimmune cause of the disease, but we would be replacing the missing cells.”
A similar device has already been safety tested in 19 people with diabetes, using smaller numbers of cells. Once implanted, the progenitor cells housed in the device did mature into islet cells, but the trial didn’t use enough cells to try to treat the condition.
Now Viacyte has implanted PEC-Direct packages containing the cells into two people with type 1 diabetes. A third person will also get the implant in the near future. Once inside the body, pores in the outer fabric of the device allow blood vessels to penetrate inside, nourishing the islet progenitor cells. Once these cells have matured – which should take about three months – the hope is that they will be able to monitor sugar levels in the blood, and release insulin as required.
If effective, it could free people with type 1 diabetes from having to closely monitor their blood sugar levels and inject insulin, although they would need to take immunosuppressive drugs to stop their bodies from destroying the new cells.