Purchase this article with an account.
J. Hua, N. Gross, B. Schulze, U. Michaelis, H. Bohnenkamp, E. Guenzi, L. L. Hansen, T. Kube, G. Martin, H. T. Agostini; In vivo Imaging of Angiogenic Activity in Laser-Induced Choroidal Neovascularization (L-CNV)of Mice Using Cationic Liposomes. Invest. Ophthalmol. Vis. Sci. 2007;48(13):1474.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Anti-angiogenic therapy is now available for patients with exudative age-related macular degeneration (AMD). To reduce the frequency of injections, a precise determination of the activity in lesions would be advantageous for the indication of treatment as well as for follow-ups. Cationic liposomes bind specifically to the activated angiogenic endothelial cells in tumor and inflammation models. We performed in vivo imaging to determine the specific uptake of fluorescent labeled cationic liposomes (EndoTag®) in L-CNV lesions using a scanning-laser ophthalmoscope (SLO) (HRA, Heidelberg Ing.).
C57Bl/6 mice underwent ARGON-laser coagulations. EndoTag® or neutral liposomes tagged with the fluorescent dye Oregon Green (OG) were injected i.v. on day 1, 5, 10 or 14, respectively after laser coagulation (each time point n=3). In vivo fluorescence imaging using a SLO was performed 60 min after the application. Flat mounts of sclera and choroid were dissected after enucleation and examined with fluorescence microscopy. The software ImageJ® was used to quantify the specific uptake of OG in both in vivo and ex vivo imaging. In addition, frozen enucleates were cross sectioned and stained for platelet/endothelial adhesion molecule (PECAM-1). OG and the immunofluorescence stain were examined with confocal microscopy and the colocalization was analyzed for the specificity of liposome uptake in lesions.
In vivo and ex vivo imaging, as well as immunochemistry demonstrate the specific uptake of EndoTag® in L-CNV. There is an increasing accumulation of EndoTag® in the lesions within 14 days after the laser coagulation, whereas no such trend was found for neutral liposomes. The uptake of EndoTag® was significantly higher compared to neutral liposomes on day 10 and 14 (ANOVA, p<0.01). Colocalization of PECAM-1 and OG confirmed the uptake of EndoTag® in L-CNV lesions.
Using fluorescent labeled EndoTag® and conventional SLO, an in vivo cellular imaging of angiogenic activity in L-CNV is possible. This could be easily transferred into precise clinical diagnostics of active AMD with the aim to facilitate the decision for anti-angiogenic therapy and the monitoring of treatment efficacy.
This PDF is available to Subscribers Only