title: Combined Optical Coherence and Fluorescence Microscopy to assess dynamics and specificity of pancreatic beta-cell tracers.
abstract: The identification of a beta-cell tracer is a major quest in diabetes research. However, since MRI, PET and SPECT cannot resolve individual islets, optical techniques are required to assess the specificity of these tracers. We propose to combine Optical Coherence Microscopy (OCM) with fluorescence detection in a single optical platform to facilitate these initial screening steps from cell culture up to living rodents. OCM can image islets and vascularization without any labeling. Thereby, it alleviates the need of both genetically modified mice to detect islets and injection of external dye to reveal vascularization. We characterized Cy5.5-exendin-3, an agonist of glucagon-like peptide 1 receptor (GLP1R), for which other imaging modalities have been used and can serve as a reference. Cultured cells transfected with GLP1R and incubated with Cy5.5-exendin-3 show full tracer internalization. We determined that a dose of 1 μg of Cy5.5-exendin-3 is sufficient to optically detect in vivo the tracer in islets with a high specificity. In a next step, time-lapse OCM imaging was used to monitor the rapid and specific tracer accumulation in murine islets and its persistence over hours. This optical platform represents a versatile toolbox for selecting beta-cell specific markers for diabetes research and future clinical diagnosis.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Corinne
authors.initials: C
authors.lastname: Berclaz
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Christophe
authors.initials: C
authors.lastname: Pache
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Arno
authors.initials: A
authors.lastname: Bouwens
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, PL-87-100 Torun, Poland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Szlag
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lopez
authors.affiliation: Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Lieke
authors.initials: L
authors.lastname: Joosten
authors.affiliation: Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Selen
authors.initials: S
authors.lastname: Ekim
authors.affiliation: Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: Brom
authors.affiliation: Radboud University Medical Center, Nijmegen, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Gotthardt
authors.affiliation: Danish Stem Cell Center, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Grapin-Botton
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors.forename: Theo
authors.initials: T
authors.lastname: Lasser
mesh_terms: D000818:Animals; D002232:Carbocyanines / Q000494:pharmacology*; D002460:Cell Line; D003412:Cricetulus; D003920:Diabetes Mellitus / Q000378:metabolism*; D005260:Female; D005456:Fluorescent Dyes; D000067757:Glucagon-Like Peptide-1 Receptor / Q000032:analysis* / Q000235:genetics; D050417:Insulin-Secreting Cells / Q000166:cytology*; D051379:Mice; D008813:Mice, Inbred ICR; D010455:Peptides; D041623:Tomography, Optical Coherence / Q000379:methods*; D000097789:Glucagon-Like Peptide-1 Receptor Agonists
chemical_list: C098793:CY5.5 cyanine dye; D002232:Carbocyanines; D005456:Fluorescent Dyes; C000593834:Glp1r protein, mouse; D000067757:Glucagon-Like Peptide-1 Receptor; D010455:Peptides; C066448:exendin 3; D000097789:Glucagon-Like Peptide-1 Receptor Agonists