The holy grail for diabetes researchers is finding a way to get the insulin-producing cells (beta or β cells) of the pancreas functioning normally. For people with Type 1 diabetes whose β cells have been destroyed by autoimmune attacks, or people with Type 2 diabetes whose β cells are basically worn out, this could mean somehow giving them new ones, a feat that has yet to be accomplished. However, we may be just a little closer to achieving that goal, according to new research published in the journal Cell Metabolism.
Led by Dr.Eiji Yoshihara from the Salk Institute in La Jolla, CA, an international team of scientists investigated the process by which mature, insulin-producing β cells could be grown in the laboratory (in vitro). Before birth, a baby receives glucose from its mother and has no need to produce its own insulin. But after birth, it must have functioning β cells to have a normal glucose metabolism — and that's when the β cells mature.
This maturation process has not been fully functional in human β cells grown from human stem cells in the lab. The cells reach a precursor stage, but are not able to respond to glucose added to their growth medium by releasing insulin, that is, they are not fully functioning β cells. These researchers discovered that a protein called estrogen-related receptor gamma (ERRγ), is necessary for the maturation process to be completed.
When the investigators added ERRγ to immature β cells in the lab, they found that they became fully functional, releasing insulin when stimulated by glucose, which is what happens in the body of non-diabetic individuals. The next step for the researchers was to demonstrate that these cells would have the same effect in vivo.
They did this by utilizing a strain of mouse that didn't produce ERRγ. These animals' β cells did not produce insulin in response to glucose. But when they were given ERRγ-stimulated β cells, they responded normally, thus demonstrating that these cells had sufficiently matured.
While this research is obviously still preliminary, it resolves some difficulties that researchers had faced in trying to cope with the non-functional β cells in diabetic humans. Pending replication by other labs, such laboratory-matured β cells could be tested in diabetic humans to see how well they ameliorate human diabetes. If they work, it could mean that diabetic people will no loner have to keep measuring their blood glucose levels and injecting insulin in order to normalize their metabolism.