Characterization of Novel ¹⁸F-Labeled Phenoxymethylpyridine Derivatives as Amylin Imaging Probes

Deposition of islet amyloid consisting of amylin constitutes one of pathological hallmarks of type 2 diabetes mellitus (T2DM), and it may be involved in the development and progression of T2DM. However, the details about the relationship between the deposition of islet amyloid and the pathology of T2DM remain unclear, since no useful imaging tracer enabling the visualization of pancreatic amylin is available. In the present study, we synthesized and evaluated six novel ¹⁸F-labeled phenoxymethylpyridine (PMP) derivatives as amylin imaging probes. All ¹⁸F-labeled PMP derivatives showed not only affinity for islet amyloid in the post-mortem T2DM pancreatic sections but also excellent pharmacokinetics in normal mice. Furthermore, ex vivo autoradiographic studies demonstrated that [¹⁸F]FPMP-5 showed intense labeling of islet amyloids in the diabetes model mouse pancreas in vivo. The preclinical studies suggested that [¹⁸F]FPMP-5 may have potential as an imaging probe that targets amylin aggregates in the T2DM pancreas.