New Methods to Increase Success Rate of Islet Transplantation
The researchers at University of Geneva (UNIGE)and Geneva
University Hospitals (HUG), Switzerland have come up with a solutin to increase
the success rate of Islet of Langherhans transplation for diabetes patients.
The new method to create a robust islets to withstand the stress of transplantation better is by adding amniotic epithelial cells, taken from the wall of the inner placenta membrane to the pancreatic cells.“These cells, very simi-lar to stem cells, are already used in other therapies, such as corneal repair for example,” says Thierry Berney, Professor in the Department of Surgery at UNIGE Faculty of Medicine and Head of HUG Transplant Division, who co-directed this work. “In our case, we found that they can promote the function of pancreatic cells, which is to produce hor-mones according to fluctuations in sugar levels.
”First step, in vitro: the addition of amniotic epithelial cells allowed the cell clusters to form regular spheres, indicating better intracellular communication and connectivity. Second step in vivo: the scientists transplanted their “super-islets” of Langerhans into diabetic mice,which quickly began to produce insulin. “Even with few cell clusters, our super islets adapted very well to their new environment and quickly became vascularized,” says Fanny Lebreton, a researcher in the Department of Surgery at UNIGE Faculty of Medicine and the first author of this work. A good vascularization is indeed the key element of any transplantation: it allows to supply the new organ with oxygen and nutrients and guarantees their survival. In addition, the artificial islets quickly began to produce insulin.
Amniotic epithelial cells are thus essential to islet survival and seem to act on two vital elements: the lack of oxygen, which usually kills a large number of transplanted islets, and the modulation of the host immune system to limit the risk of rejection. “In any transplant, the first step is to lower the recipient’s immunity to limit the risk of rejection, says Ekaterine Berishvili. Amniotic epithelial cells have the unique characteristic of protecting the foetus, which is also a “non-self,” from attacks by its mother’s immune system. We believe that the same mechanism is at work to protect the grafts.” The protective mechanism, observed here on cell transplants, could also take place on other types of transplants or even in xenotransplantation – where non-human cells or organs are transplanted into humans. These discoveries now need to be confirmed on human subjects. Since the use of amniotic epithelial cells is already common in other clinical settings without adverse side effects, this could be done rela-tively quickly. An important hope for all those awaiting a transplant.