TY - JOUR T1 - Optoacoustic imaging of Glucagon-like Peptide 1 Receptor with a near-infrared exendin-4 analog JF - Journal of Nuclear Medicine JO - J Nucl Med DO - 10.2967/jnumed.120.252262 SP - jnumed.120.252262 AU - Sheryl Roberts AU - Eshita Khera AU - Crystal Choi AU - Tejas Navaratna AU - Jan Grimm AU - Greg M. Thurber AU - Thomas Reiner Y1 - 2020/10/01 UR - http://jnm.snmjournals.org/content/early/2020/10/23/jnumed.120.252262.abstract N2 - Limitations in current imaging tools have long challenged the imaging of small pancreatic islets in animal models. Here, we report the first development and in vivo validation testing of a broad spectrum and high absorbance near infrared optoacoustic contrast agent, E4x12-Cy7. Our near infrared tracer (E4x12-Cy7) is based on the amino acid sequence of exendin-4 and targets the glucagon-like peptide-1 receptor (GLP-1R). Cell assays confirmed that E4x12-Cy7 has a high binding affinity (IC50 = 4.6 ± 0.8 nM). Using the multi-spectral optoacoustic tomography (MSOT), we imaged E4x12-Cy7 and optoacoustically visualized β-cell insulinoma xenografts in vivo for the first time. In the future, similar optoacoustic tracers that are specific for β-cells and combines optoacoustic and fluorescence imaging modalities could prove to be important tools for monitoring the pancreas for the progression of diabetes. ER -