Phd ceremony Ms. D. de Paula Faria: New avenues in PET imaging of multiple sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease characterized by neuroinflammation and myelin loss in the central nervous system. Molecular imaging, such as PET (Positron Emission Tomography), may become an important tool for monitoring disease progression and treatment effects in MS patients. PET imaging uses a short-lived radioactive compound, called tracer, which is injected intravenously and allows the acquisition of a 3D image of body. The PET image contains specific molecular information about (abnormalities in) physiological and biochemical processes inside the patient. The aim of this thesis was to evaluate the potential of PET imaging, using different tracers, for monitoring myelin and inflammation changes in the central nervous system of experimental animals, in which MS-like disease was induced. We confirmed that microglia activation and monocyte invasion in the brain, could be well monitored by [ 11 C]PK11195 PET. The image signal corresponded well with data from histochemical analysis. PET imaging appeared a very sensitive tool to measure the effects of an anti-inflammatory treatment. In addition, we tested 3 novel PET tracers for myelin and showed that PET imaging can detect changes in myelin content (demyelination and remyelination) in animal models of MS. The most promising results were obtained with the tracer [ 11 C]MeDAS. Further research on the specificity and safety of this PET tracer is required before it can be used in the clinic. In conclusion, we have shown that PET imaging is a very promising tool for in vivo monitoring of disease processes in the brain and spinal cord of MS patients.