Grow your own transplant - a possibility for men with diabetes
Men that have type 1 diabetes might be able to grow insulin-producing cells from their testicular tissue.
Georgetown University Medical Center researchers say it’s possible and they presented their findings on Sunday at the American Society of Cell Biology’s 50th annual meeting in Philadelphia.
Their laboratory and animal study is proof the principal that human spermatogonial stem cells (SSCs) extracted from testicular tissue can transform into insulin-secreting beta islet cells usually found in the pancreas. The researchers say they accomplished this amazing feat without the use of any of the extra genes now used in most labs to turn adult stem cells into a chosen tissue.
"No stem cells, adult or embryonic, have been induced to secrete enough insulin yet to cure diabetes in humans, but we know SSCs have the potential to do what we want them to do, and we know how to improve their yield," said the study’s lead investigator, G. Ian Gallicano, Ph.D., an associate professor in the Department of Cell Biology and director of the Transgenic Core Facility at GUMC.
Based on continuing progress, Gallicano says his strategy could give a unique solution to treatment of individuals with type 1 diabetes (juvenile onset diabetes). Many therapies have been tried for these patients, but they each have drawbacks. Transplanting islet cells from dead donors can end in rejection, plus donations are not readily available.
Researchers also have been able to cure diabetes in mice using induced pluripotent stem cells, which are adult cells that have been reprogramming with other genes to act like embryonic stem cells, but this method can make tumors in transfected tissue, as well as problems stemming from the external genes used to make IPS cells, Gallicano said.
So instead of using IPS cells the researchers switched to a more readily available source of stem cells, the SSCs that are the beginning precursors to sperm cells. They extracted these cells from deceased human organ donors.
Since SSCs already have the necessary genes to become embryonic stem cells, it is not necessary to add in any new genes to get them to change into the progenitor cells, Gallicano said. "These are male germ cells as well as adult stem cells."
"We found that once you take these cells out of the testes niche, they get confused, and will form all three germ layers within several weeks," he says. "These are true, pluripotent stem cells."
The researchers took 1 gram of tissue from human testicles and made about 1 million stem cells in the laboratory. These cells had many of the bio-markers that characterize normal beta islet cells.
They then had to transplant those cells into the back of the immune deficient diabetic mice, and were able to lower glucose levels in the mice for nearly a week, demonstrating the cells were producing enough insulin to reduce hyperglycemia.
The effect only lasted one week, Gallicano says the newest research has shown the yield can be significantly increased.
The research was funded in part by the American Diabetes Association, patient contributions to the GUMC Office of Advancement, support from GUMC diabetes specialist Stephen Clement, M.D., and a grant from GUMC.
Interestingly, Georgetown University made sure to let the media know that the authors of the research have no personal financial interests related to the study.