Effect of Gelofusine on GLP1-receptor Imaging

Beta-cell imaging in vivo Reliable, sensitive and specific non-invasive methods for comprehensive structural and functional characterization of living pancreatic beta-cells in vivo (and in vitro) would not only enhance our understanding of the pathophysiology of various diseases, but also enable longitudinal in vivo assessment of beta cell mass (BCM) and distribution in patients with e.g. diabetes (including patients who received beta cell replacement therapy). Additionally, it can help in diagnosing insulinomas and congenital hyperinsulinism and when coupled to other biomarkers it could aid patient stratification and enable patient-specific optimized treatment strategies. Inhibiting the reabsorption of radiolabelled peptides It has been shown, both in vitro and in vivo, that the kidney uptake of radiolabelled peptides can be reduced by co-infusion of agents that inhibit the reabsorption of these peptides. One of these agents is succinylated gelatin (Gelofusine), a plasma expander that consists of a mixture of collagen-derived peptides. Previous clinical observations have shown that Gelofusine infusion results in tubular proteinuria of both albumin and β2-microglobulin. Although the exact mechanism for this proteinuria is not completely understood, the megalin receptor system is most likely involved. Based on pre-clinical studies in mice and rats, it has been known that kidney uptake is significantly reduced for various tracers when co-infused with Gelofusine, like 111In-Octreotide 111In-Minigastrin, 68Ga-exendin-4 and 111In-DTPA-AHX-Lys40-Exendin 4. Additionally, it was shown that Gelofusine also reduces the renal retention of 111In- Octreotide by 45% in humans. In the current study, investigators will determine whether Gelofusine has also an effect on kidney retention of 111In-DTPA-AHX-Lys40-Exendin 4 in humans.