(18)F-Labeling of Mannan for Inflammation Research with Positron Emission Tomography.

Abstract

Recently mannan from Saccharomyces cerevisiae has been shown to be able to induce psoriasis and psoriatic arthritis in mice, and the phenotypes resemble the corresponding human diseases. To investigate the pathological processes, we set out to label mannan with fluorine-18 ((18)F) and study the (18)F-labeled mannan in vitro and in vivo with positron emission tomography (PET). Accordingly, mannan has been transformed into (18)F-fluoromannan with (18)F-bicyclo[6.1.0]nonyne. In mouse aorta, the binding of [(18)F]fluoromannan to the atherosclerotic lesions was clearly visualized and was significantly higher compared to blocking assays (P < 0.001) or healthy mouse aorta (P < 0.001). In healthy rats the [(18)F]fluoromannan radioactivity accumulated largely in the macrophage-rich organs such as liver, spleen, and bone marrow and the excess excreted in urine. Furthermore, the corresponding (19)F-labeled mannan has been used to induce psoriasis and psoriatic arthritis in mice, which indicates that the biological function of mannan is preserved after the chemical modifications.

• Authors: Xiang-Guo Li, Cecilia Hagert, Riikka Siitonen, Helena Virtanen, Outi Sareila, Heidi Liljenbäck, Jouni Tuisku, Juhani Knuuti, Jörgen Bergman, Rikard Holmdahl, Anne Roivainen
• Journal: ACS medicinal chemistry letters (ACS Med Chem Lett) Vol. 7 Issue 9 Pg. 826-30 (Sep 08 2016) ISSN: 1948-5875 [Print] United States
• PMID: 27660685 (Publication Type: Journal Article)