Noninvasive Molecular Imaging of Apoptosis in Central Nervous System by Magnetic Resonance Imaging: Emerging to Clinical Practice
Apoptosis involves a particular type of cell death that plays an important role in tissue turnover and homeostatic regulation. Remove unwanted cells in multicellular organisms and unicellular organized by this process. Cell apoptosis begins with the production and release of various factors. The effects of apoptosis depend on the environment in which is occur programmed cell death. Apoptosis in some cells also causes release of various factors such as cytokines and subsequently mediated activation of other protein mediators of immune and inflammatory response. Today, using genes, inducer metabolites and inhibitors involved in of apoptosis, or programmed cell death, can be immune system (the balance between cellular and humoral immune) is directed towards the desired immune response. There are different methods for detection of apoptotic cells and each of these methods alone cannot be used as the criterion of apoptosis. The activation of caspases also is a marker for cellular damage in diseases. Caspases as an indicator is specific apoptosis therefore determine the activation of caspase can be used to differentiate between necrosis and apoptosis. Molecular imaging is ideally suited to measuring early response by quantifying cellular metabolism, proliferation and apoptosis, activities altered early in treatment. There are now several possible Magnetic Resonance Imaging (MRI) based approaches for detecting apoptosis, in particular tumor apoptosis, which have the potential to be translated into clinical application. Detection of cellular lipid droplet accumulation, using localized Magnetic Resonance Spectroscopy (MRS) and changes in tissue architecture using Diffusion-Weighted Imaging (DWI) has the virtues that they are completely non-invasive and thus could be implemented in the clinical practice now. Potential disadvantages include a lack of specificity for apoptosis and the possibility that they may be limited in detecting relatively low but clinically relevant, levels of cell death. Finally using labeled molecular factors and inducer proteins and also measurement of metabolites by non-invasive medical imaging techniques such as magnetic resonance spectroscopy can be identified the actual mechanisms and pathways of apoptosis as well by manipulated these pathways may be effective in the prevention of diseases such as autoimmune and neurodegenerative disorders.