Scientists at Karolinska Institutet and the University of Miami have developed a method for studying complicated cell processes, such as the secretion of insulin in the pancreas, of living animals -- something that has not been possible to this date. The new method, which involves the transplantation of a tiny part of the pancreas onto the iris of mice, paves the way for radical approaches to diabetes research, which has previously been conducted on single cells in artificial laboratory environments.
The eye acts like a window through which we can watch complicated biological processes at a cellular level for a long time without having to operate on the animal, which is therefore spared any suffering, says Professor Per-Olof Berggren, who led the study at the Rolf Luft Research Centre for Diabetes and Endocrinology, Karolinska Institutet. We can also confirm that diabetic mice which had pancreatic beta cells transplanted onto the eye were completely cured.
Insulin secretion from the beta cells in the part of the pancreas called the Islets of Langerhan is a complicated process, which if it fails to work properly induces diabetes. However, in order to do something about the defects in the beta cells, scientists must first know how they work under normal conditions and identify all the signals that usually affect the secretion of insulin. To date, much of the research has been confined to in vitro rather than in vivo studies of individual beta cells and the Islets of Langerhan.
In a new paper published in the prestigious scientific journal Nature Medicine, scientists describe the development of a new experimental model based on transplanting Islets of Langerhan cells onto the anterior chamber of the mouse eye. These cells fuse with the iris and are quickly supplied with blood vessels and nerves. Using a microscope, the scientists are able to register changes in specific cellular markers through the cornea, allowing them to make detailed studies of the function of different signal systems and their role in the regulation of beta cell function and survival in the living, healthy animal.
The scientists believe that the study now published will prove of significant benefit to diabetes research in a variety of ways, from gene expression and how blood vessels and nerves are established in the insulin-secreting part of the pancreas, to the testing of new drugs on living organisms. However, the discovery can also be used by researchers to study other types of cell than those in the pancreas. One great advantage of the method is that the mice can continue to live normal, discomfort-free lives. It is therefore likely that the number of experimental animals can eventually be reduced.
Journal reference: Stephan Speier, Daniel Nyqvist, Over Cabrera, Jia Yu, R. Damaris Molano, Antonello Pileggi, Tilo Moede, Martin Köhler, Johannes Wilbertz, Barbara Leibiger, Camillo Ricordi, Ingo B. Leibiger, Alejandro Caicedo and Per-Olof Berggren. Non-invasive in vivo imaging of pancreatic islet cell biology. Nature Medicine, Online Early Edition, 7 March2008
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