Stem cell researchers at Harvard University have devised a method for creating large quantities of human insulin-producing beta cells, which could soon lead to a cure for type 1 diabetes as well as a new treatment for type 2 diabetes. The cells are currently being trialled in animals and non-human primates with hopes human trials could take place in the near future..
The researchers built a three-dimensional cell culture system using 500 ml spinner flasks containing undifferentiated human pluripotent stem cells. The flasks were placed on a magnetic stirrer and the cells were fed special proteins over a 33-day period. After further treatment and imaging, the insulin-secreting stem-cell-derived-β cells were transplanted into diabetic mice, which had a higher survival rate and lower blood glucose level than the control group under three different scenarios.
The cells produced were found to mimic the function of human islets (clusters of cells scattered throughout the pancreas), which are crucial in regulating blood sugar. Type 1 diabetics lack the beta cells that monitor blood sugar levels and release insulin to normalize it because their immune system attacks and destroys these cells. Transplanted beta cells grown in a lab may provide a long-term solution, but until now they could not be grown in sufficient quantities to treat the disease.
The other remaining piece in the diabetes cure puzzle involves pinpointing a method for protecting the transplanted cells – around 150 million of them in each patient – from immune system attack (otherwise patients would require repeated and regular or semi-regular transplantations). Lead researcher Doug Melton is collaborating with Daniel G. Anderson of the Koch Institute at MIT on an implantation device that has thus far protected beta cells implanted in mice for many months.
Anderson described the work of Melton's lab as "an incredibly important advance for diabetes" as it "opens the doors to an essentially limitless supply of tissue for diabetic patients awaiting cell therapy."
Type 1 diabetes affects an estimated three million Americans, who for the most part must currently regulate their blood sugar levels by injecting insulin multiple times a day. But without the kind of fine-tuned metabolic control that glucose-sensing, insulin-secreting beta cells can provide, they face potential complications as severe as blindness and loss of limbs. Transplanted beta cells could also help type 2 diabetics who are dependent on insulin injections.
"We are now just one pre-clinical step away from the finish line," said Melton, who hopes to see transplantation trials in humans begin in the next few years.
A paper describing the research was published in the journal Cell.
Source: Harvard University
