Innovative strategies in in vivo apoptosis imaging
Johann Schoenberger1, Johann Bauer, Jutta Moosbauer
1Department of Nuclear Medicine, University of Regensburg, Germany. johann.schoenberger@klinik.uni-regensburg.de
Abstract:
Apoptosis (programmed cell death) plays a key role in the pathogenesis of many disorders including cerebral and myocardial ischemia, autoimmune and neurodegenerative diseases, infections, organ and bone marrow transplant rejection, and tumor response to chemotherapy and/or radiotherapy. Apoptosis in itself represents a complex mechanism where numerous (pro-apoptotic and anti-apoptotic) molecules interact in an elaborate manner. Since the original description by Kerr et al. in 1972, clinical assessment of apoptosis has always required biopsies or aspirated material for in vitro investigations. Several well-established methods are available for in vitro tests using tissue specimens. However, a non-invasive detection of apoptosis would be of great benefit for many patients in various situations. Today, non-invasive techniques for direct in vivo detection of apoptotic cells are rare and urgently need improvement. The early in vivo detection of apoptotic cells can provide the physician with important information to develop further therapeutic strategies in chemotherapy or radiotherapy of tumors, in transplantation of organs, or in healing of infarct areas. In some preliminary publications, several authors reported on the in vivo use of caspase-inhibitors and annexin V, labeled with indium-111, technetium-99m, iodine-123, iodine-124 or fluoride-18. In the present paper, we review the current applicability of both techniques for in vivo apoptosis imaging, and discuss the methodical problems.
Insights
Non-invasive detection of apoptosis (programmed cell death) is crucial for managing various diseases. Current in vivo imaging techniques using radiolabeled caspase inhibitors and annexin V show promise but require further development.
Area of Science:
- Biomedical imaging
- Cellular biology
- Pathogenesis research
Background:
- Apoptosis is integral to numerous diseases, including ischemia, autoimmune disorders, and cancer.
- Current apoptosis assessment relies on invasive in vitro biopsy methods.
- Non-invasive in vivo detection of apoptosis is needed for timely therapeutic strategy development.
Purpose of the Study:
- To review the current applicability of in vivo apoptosis imaging techniques.
- To discuss methodical challenges in current non-invasive apoptosis detection.
Main Methods:
- Review of preliminary publications on in vivo apoptosis imaging.
- Analysis of radiolabeled caspase inhibitors and annexin V for imaging.
- Discussion of imaging agents labeled with isotopes like 111In, 99mTc, 123I, 124I, and 18F.
Main Results:
- Radiolabeled annexin V and caspase inhibitors have been explored for in vivo apoptosis imaging.
- These agents offer potential for early detection of apoptotic cells in various clinical scenarios.
- Methodical problems and limitations in current techniques are identified.
Conclusions:
- Non-invasive in vivo apoptosis imaging holds significant clinical potential.
- Further refinement of current techniques is necessary for widespread clinical adoption.
- Improved imaging methods will aid therapeutic decisions in oncology, transplantation, and ischemic diseases.
