Researchers Make Stem Cells That Secrete Insulin

Scientists reported on Wednesday that they were able to control diabetes in mice by harnessing human embryonic stem cells. The work raised the prospect that the embryonic cells might one day be used to provide insulin-producing replacement cells to treat the disease in people.

Scientists have found a way to convert human embryonic stem (ES) cells into cells that release insulin in response to glucose and ease a diabetes-like condition in mice, a new study says.

Further research and development of this technique could lead to a renewable source of cells for treatment of people with diabetes, according to Emmanuel Baetge, of Novocell Inc., in San Diego, and colleagues, who published their work online in the current issue of Nature Biotechnology.

Type 1 and some forms of type 2 diabetes involve the loss of pancreatic beta cells, which regulate blood glucose (sugar) levels by releasing insulin, according to background information in a news release about the study.
The scientists, at the biotechnology company Novocell, turned the stem cells into cells that produced insulin in the mice. Those cells kept blood sugar in check after the mice’s own insulin-producing cells were destroyed.

“For those who say there is not much evidence that embryonic stem cells can cure diabetes, there you go,” said Dr. Camillo Ricordi, director of the Diabetes Research Institute at the University of Miami, who was not involved in the research.
Still, a small number of the mice developed tumors, and some experts said the cells might not be well-characterized enough for use in people. Indeed, in the Novocell experiment, 7 of the 105 mice with the implants developed a sort of tumor called teratomas. Dr. Baetge said Novocell could probably have reduced or eliminated the teratomas if it had purified the cells before implanting them.

In any event, Novocell said it would be several years before any human tests could begin.
In previous work, Baetge and the team were able to coax human ES cells part of the way toward becoming beta cells, but not far enough for them to carry out the key function of mature beta cells, which is the release of insulin in response to glucose.

In this new study, the researchers transplanted immature beta cells derived from human ES cells into mice whose beta cells had been destroyed by chemical treatment. After one to three months, the transplanted cells developed into glucose-responsive, insulin-secreting cells and helped control blood glucose levels in the mice.

Previous research demonstrated that transplantation of pancreatic beta cells (within islets) can help control diabetes in humans. But the therapy relies on cells from donor pancreases, meaning that the supply of such cells is limited. That’s why scientists are trying to develop alternative sources of beta cells, such as those derived from human ES cells.

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DID YOU KNOW:
Inpatient Cardiac Arrest Survival Worse During Night, Weekend Shifts: Hospitalized patients who go into cardiac arrest on nights and/or weekends have a significantly lower chance of survival than patients who go into arrest during weekday shifts, the Wall Street Journal reports. Among nearly 59,000 patients in 507 US hospitals who went into cardiac arrest, about 20% of those with arrests occurring during day or evening shifts survived to discharge, compared with about 15% of those who went into arrest at night. Survival of weekday cardiac arrests was also higher than weekend day/evening arrests (about 21% vs 17%). The differences were significant and held even after controlling for potential confounders such as patient, event, and hospital characteristics. See This Weeks’ Item #6    JAMA,February 20, 2008

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