Imaging of Human Insulin Secreting Cells with Gd-DOTA-P88, a Paramagnetic Contrast Agent Targeting the Beta Cell Biomarker FXYD2γa

• Published in: Molecules (Basel, Switzerland) Vol. 23; no. 9; p. 2100
• Main Authors: Demine, Stéphane, Balhuizen, Alexander, Debaille, Vinciane, Joosten, Lieke, Fereau, Maïté, Chilla, Satya Narayana Murthy, Millard, Isabelle, Scharfmann, Raphaël, Egrise, Dominique, Goldman, Serge, Marchetti, Piero, Gotthardt, Martin, Laurent, Sophie, Burtea, Carmen, Eizirik, Decio L
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.08.2018; MDPI
• Subjects: Animals; beta cell imaging; Beta cells; Biomarkers; CHO Cells; Computer simulation; Contrast agents; Contrast Media - chemistry; Cricetulus; Diabetes; Fibrosis; Gene Expression; Grafts; Heterocyclic Compounds - chemistry; Heterografts; Humans; Insulin; Insulin-Secreting Cells - metabolism; Insulin-Secreting Cells - transplantation; Kidney diseases; Kidneys; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical imaging; Mice; Molecular Imaging - methods; MRI; non-invasive imaging; Optimization; Organometallic Compounds - chemistry; pancreatic beta cell; Pancreatic islet transplantation; paramagnetic contrast agent; peptide-based imaging; Peptides; Ratios; Renal function; Sodium-Potassium-Exchanging ATPase - genetics; Sodium-Potassium-Exchanging ATPase - metabolism; Type 1 diabetes; Type 2 diabetes; Xenografts; Type 2 diabetes; pancreatic beta cell; MRI; Type 1 diabetes; paramagnetic contrast agent; beta cell imaging; non-invasive imaging; peptide-based imaging
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules23092100

Non-invasive imaging and quantification of human beta cell mass remains a major challenge. We performed pre-clinical in vivo validation of a peptide previously discovered by our group, namely, P88 that targets a beta cell specific biomarker, FXYD2γa. We conjugated P88 with DOTA and then complexed it with GdCl₃ to obtain the MRI (magnetic resonance imaging) contrast agent (CA) Gd-DOTA-P88. A scrambled peptide was used as a negative control CA, namely Gd-DOTA-Scramble. The CAs were injected in immunodeficient mice implanted with EndoC-βH1 cells, a human beta cell line that expresses FXYD2γa similarly to primary human beta cells. The xenograft-bearing mice were analyzed by MRI. At the end, the mice were euthanized and the CA biodistribution was evaluated on the excised tissues by measuring the Gd concentration with inductively coupled plasma mass spectrometry (ICP-MS). The MRI and biodistribution studies indicated that Gd-DOTA-P88 accumulates in EndoC-βH1 xenografts above the level observed in the background tissue, and that its uptake is significantly higher than that observed for Gd-DOTA-Scramble. In addition, the Gd-DOTA-P88 showed good xenograft-to-muscle and xenograft-to-liver uptake ratios, two potential sites of human islets transplantation. The CA shows good potential for future use to non-invasively image implanted human beta cells.