Dottorato in MORFOGENESI E INGEGNERIA TISSUTALE

Titolo della tesi: X-Ray Phase Contrast Tomography applied to Neurodegenerative Disorders

X-ray Phase Contrast Tomography (XPTC) offers the possibility to simultaneously investigate the highly complex vascular network and neuronal network in the context of organ as a whole and, compare physiological vs. pathological states at the level of crucial disease targets. In fact, XPCT provides high-contrast and high-spatial resolution images of low absorbing tissues with no use of contrast agent or sample staining. For this reason, XPCT emerges as added-value technology for the investigation of neurodegenerative disorders. In particular, XPCT enabled us to investigate mouse model APP/PS1 of Alzheimer’s Disease (AD), demonstrating capillary occlusions and damages, close associations between plaques and damaged vessels both in the hippocampal and cerebellum regions. Moreover XPCT, changes induced in APP/PS1 mouse brains by mesenchymal stem cells exposed in vitro to AD mouse brain homogenates (MSC-CS) treatment has been investigated, unveiling MSC-CS action on amyloid plaque load. To extract quantitative information from images, a new segmentation approach has been developed based on machine learning. A random forest-based classifier has been used in order to automatically segment feature of interest in tomographic volumes including cells, vascular network and amyloid plaques. However, additional efforts are necessary for the comprehension of disease mechanisms and monitoring of therapeutic approaches. Although XPCT revealed to be a powerful technique for preclinical studies, it lacks in specificity provided by classical immunohistochemistry or histology. A combination of these techniques with XPCT has been thought and developed with the purpose of combining specificity with high-resolution 3D information. Functionalized gold nanoparticles have been injected in a mouse model of neurodegenerative disorder to target disease-relevant cell populations. The idea is to boost research in preclinical studies and shed light on future in-vivo investigation by using IH-XPCT.