Christin Perlitz

Comparison of Two Tricarbocyanine-Based Dyes for Fluorescence Optical Imaging

Optical technologies are evolving in many biomedical areas including the biomedical imaging disciplines. Regarding the absorption properties of physiological molecules in living tissue, the optical window ranging from 700 to 900 nm allows to use fluorescent dyes for novel diagnostic solutions. Here we investigate the potential of two different carbocyanine-based dyes fluorescent in the near infrared as contrast agents for in vivoimaging of subcutaneously grown tumours in laboratory animals. The primary aim was to modify the physicochemical properties of the previously synthesized dye SIDAG to investigate the effect on the in vivoimaging properties.

ED-B fibronectin (ED-B) can be targeted using a novel single chain antibody conjugate and is associated with macrophage accumulation in atherosclerotic lesions

It has been shown that ED-B fibronectin (ED-B) is a potential target for plaque imaging. The aim of this study was to test a novel modified single chain anti-ED-B antibody (scFv) conjugated for near infrared fluorescence imaging (NIRF) with tetrasulfonated carbocyanine-maleimide (TSC-scFv) and to examine the association of ED-B with the presence of macrophages in a murine model of atherosclerosis. Expression of ED-B was observed in plaque areas in apolipoprotein E–deficient (apoE–/–) mice which increased with age and plaque load. Robust imaging was possible after explantation of the aorta and demonstrated a strong NIRF signal intensity in focal aortic and brachiocephalic plaque lesions, whereas no signals were found in undiseased areas. Plaque lesion ED-B was expressed by smooth muscle cell and was closely associated to macrophage infiltrates. Although not expressed by the same cell type, there was a significant correlation (p<0.01) between ED-B and macrophage immunoreactivity. In vitro human coronary and mouse smooth muscle cells significantly increased ED-B expression after angiotensin II and TNF-α treatment.This study demonstrates that plaque NIRF imaging is feasible with a novel single chain antibody and that ED-B expression is closely associated with inflammation in experimental atherosclerosis.

Molekulare Bildgebung des Mammakarzinoms in einem transgenen Mausmodell

Background: Purpose of the study was to detect early breast cancer and its precursors by in vivo optical molecular imaging in an animal model. Material and methods: Females of the transgene mouse strain WAP-TNP8 develop non-invasive and consequently invasive tumours of the mammary glands due to specific expression of the viral SV40 large tumour antigen induced by lactation. The molecular target for imaging was extradomain-b fibronectin (EDB-FN), which is associated with tumour angiogenesis. The optical probe was designed as a compound of an anti-EDB-FN antibody fragment and a near-infrared fluorescent dye. 30h after intravenous injection of the contrast agent, optical imaging was performed using a pulsed Laser system for excitation and an intensified CCD-camera to record fluorescence images. After optical molecular imaging all animals were sacrified and the tumours were examined histologically. Results: Initiated transgene female animals developed palpable masses of the mammary gland within 6 months (median 4 months). Imaging was performed in 5 animals with a total of 9 tumours (diameter 2–7mm, median 4mm). Applying optical molecular imaging 8 of 9 tumours were detected. The urogenital tract was contrasted unspecifically. Histological examination proved invasive epithelial tumours of the mammary gland in all cases. Conclusion: Breast cancer can be detected in vivo by near-infrared fluorescence molecular imaging targeting neoangiogenesis in a transgene mouse-model.