The role of labeled Annexin A5 in imaging of programmed cell death. From animal to clinical imaging.

Programmed cell death plays a critical role in embryology, homeostasis and disease. However, until recently no non-invasive imaging modality has been able to visualize this process directly. Annexin A5 binds to cells undergoing programmed cell death. When labeling this protein, Annexin A5 becomes a tool for the detection of programmed cell death in vitro and in vivo. Labeled Annexin A5 has enabled our group and others to detect programmed cell death non-invasively in animals and patients. This review will highlight the development of this imaging modality in cellular and animal models. Furthermore, we will discuss Annexin A5 imaging in human disease. We will focus on the clinical applications and their relevance, limitations and future perspectives of non-invasive imaging of programmed cell death using labeled Annexin A5.

Molecular imaging of cell death in intracardiac tumours: A new approach to differential diagnosis in cardiac tumours.

BACKGROUND: Primary endocardial tumours are rare, but may impose a difficult clinical problem. The definite diagnosis regarding the nature of the tumour is often made after surgery. This is due to the fact that current non-invasive imaging techniques are unable to inform us about the nature of the tumour. In addition, invasive techniques can not be used to obtain biological information of the tumour in these cases, because they carry a high risk of embolic complications. OBJECTIVE: To assess the possibility of a novel modality of imaging, molecular imaging, in the diagnosis of primary intracardiac tumours. METHODS: We evaluated two patients with a primary cardiac tumour. Prior to therapy, we infused human recombinant annexin-V Tc99-m and thallium 201. We used a dual isotope single photon emission computed tomography technique. This allowed us to obtain information about the relation between the anatomical position of the left ventricle and the uptake of the labelled annexin-V within the thoracic cavity. RESULTS: The patient with a malignant primary cardiac tumour showed uptake of labelled annexin-V within the area of the tumour. After surgery, the malignant nature was confirmed by histological analysis. The patient with a benignant intracardiac tumour showed no uptake of annexin-V within the area of the tumour. CONCLUSION: This novel imaging technique, molecular imaging, may be of help to differentiate non-invasively between a malignant and benignant primary intracardiac tumour.