The pig as animal model in diabetes research

Diabetes mellitus is a common and complicated disease and the numbers of affected people are increasing throughout the world, with no peak in sight at this point. Even so, the disease development is not fully understood and no permanent cure is available. In order to better understand the disease progression, evaluate treatment responses and assess the viability of transplanted beta cells, a non-invasive method to determine the pancreatic beta cell mass (BCM) is much warranted. Currently, the BCM can only be determined post mortem.

Positron emission tomography with computed tomography (PET/CT) is an imaging method that might be suitable for this purpose if a beta cell-specific PET-tracer can be developed. In the present study the glucagon like peptide-1 receptor (GLP-1R), which is expressed on beta cells, was the target for a newly developed PET-tracer and the tracer uptake in the pancreas was examined in healthy pigs and pigs with induced diabetes. The hypothesis was that no uptake would be seen in the pancreas of diabetic pigs lacking beta cells, if the targeted GLP-1R was specific to these cells.

The study is a collaboration between the Department of Clinical Sciences; SLU and the PET-Centre and the Nordic Network for Islet Transplantation, UU. The PET/CT experiments showed GLP-1R-mediated uptake of PET-tracer‎ in the pancreas of both non-diabetic and diabetic pigs. GLP-1R availability did not differ between the groups and GLP1-R is therefore not a suitable imaging biomarker for native pancreatic beta cells in pigs.