Since applications of nanotechnologies for life and health sciences are booming, magnetic nanoparticles (NP) have undergone considerable development. They combine physical, chemical and magnetic properties that make them appropriate as contrast agents for diagnosis using medical imaging techniques such as Magnetic Resonance Imaging (MRI) or ultrasonic imaging. Nanometric contrast agents are made of metallic rare earth elements (Gd) or transition metal (Mn, Fe) oxide cores.
The storage and catabolism of Ultrasmall Super Paramagnetic Iron Oxide (USPIO) nanoparticles was analyzed through a multiscale approach combining Two Photon Laser Scanning Microscopy (TPLSM) and High-Resolution Transmission Electron Microscopy (HRTEM) at different times after intravenous injection (iv) in an atherosclerotic ApoE-/- mouse model. The atherotic plaque features and the USPIOs heterogeneous biodistribution were revealed from organ’s scale down to subcellular level. The biotransformation of the nanoparticle iron oxide (maghemite) core into ferritin, the non-toxic form of iron storage, was demonstrated for the first time ex vivo in atherosclerotic plaques as well as in spleen, the iron storage organ. These results rely on an innovative spatial and structural investigation of USPIO’s catabolism in cellular phagolysosomes. This study showed that these nanoparticles were stored as non-toxic iron compounds: maghemite oxide or ferritin, which is promising for MRI detection of atherosclerotic plaques in clinic using these USPIOs .
 VA Maraloiu, F Appaix, A Broisat et al., Nanomedicine: Nanotechnology, Biology and Medicine 12 (1), 191-200 (2016)
The two-photon microscopy studies were performed on the National Platform of Intravital Microscopy in Grenoble (France Life Imaging). This platform was partly funded by the French program “Investissement d’Avenir” run by the “Agence Nationale pour la Recherche”; grant “Infrastructure d’avenir en Biologie Santé – ANR11-INBS-0006”. Researches were partially granted by the French National Agency for Research (ANR) in the frame of the INFLAM project and partially supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number PN-II-RU-PD-2011-3-0067.
To cite this abstract:Valentin-Adrian Maraloiu, Florence Appaix, Alexis Broisat, Dominique Le Guellec, Valentin Serban Teodorescu, Catherine Ghezzi, Boudewijn van der Sanden, Marie Genevieve Blanchin; Multiscale investigation of USPIO nanoparticles in atherosclerotic plaques and their catabolism and storage in vivo. The 16th European Microscopy Congress, Lyon, France. http://emc-proceedings.com/abstract/multiscale-investigation-of-uspio-nanoparticles-in-atherosclerotic-plaques-and-their-catabolism-and-storage-in-vivo/. Accessed: August 27, 2017
EMC Abstracts - http://emc-proceedings.com/abstract/multiscale-investigation-of-uspio-nanoparticles-in-atherosclerotic-plaques-and-their-catabolism-and-storage-in-vivo/