Final Report Summary - ADVASCULATURE (Clot formation as a potential diagnostic tool and therapeutic target for Alzheimer's disease) Alzheimer’s disease (AD) is the leading cause of dementia in the elderly that currently affects over 36 million people worldwide, number that is predicted to triple by 2050. In fact, the World Health Organization regards it as a true epidemic with very important social and economic costs, which are increasing in an alarming manner. This disease not only affects the patients by stealing their minds, leading to memory loss, confusion, impaired judgment, and inability to communicate and to perform daily routine activities, but this disease is also devastating for families and caregivers who can also become stressed and depressed. Another implication of this overwhelming disease is the economic burden. AD has been estimated to cost the world $604 billion in 2010 alone. Therefore, with more than 100 million people predicted to be affected within the next few years, there will be no health system able to cope with this. A modest delay in the onset of AD by 2 years could translate into avoiding 23 million AD cases by 2050. Accumulating evidence links this overwhelming disease with vascular risk factors. These correlations, together with profound alterations of cerebrovascular structure and function present in AD, suggest a “vascular hypothesis”, where vascular pathology eventually leads to neurodegeneration and subsequent cognitive decline. A decrease in cerebral blood flow has been reported in AD patients and, moreover, a correlation between the level of cerebral hypoperfusion and the degree of dementia has been identified. Several pieces of evidence indicate that there is an increased obstruction of the cerebral blood vessels in the AD brain that could strongly affect the overall cerebral circulation. In vivo clot formation experiments in AD mice showed not only that the AD brain is more prone to clot, but also once the clot has been formed it is more resistant to degradation. Also, the number of spontaneously stalled brain capillaries is significantly increased in AD mouse models, which can provoke an important decrease in the downstream cerebral blood flow. These obstructions in AD cerebral vessels could initiate and/or aggravate the brain hypoperfusion and inflammation present in the AD brain. Cerebral hypoperfusion seems to be a good indicative for dementia conversion, which suggests that the occlusion of vessels might be happening at very early stages of the disease, many years before the clinical manifestation of AD.In this application Dr. Cortes-Canteli proposed to work on two different aspects of AD: the therapeutic part and the diagnostic aspect, both of them based in the fact that abnormally increased thrombosis is present in AD. This approach has been multidisciplinary, since disciplines as different as magnetic resonance imaging (MRI) and immunohistochemistry will be used towards the same goal, but at the same time has a deep interdisciplinary component, since for example nanotechnologists and molecular biologists have worked together to unravel a new diagnostic tool for AD.Aim 1- Characterization of in vivo imaging approaches to detect the occlusions present in the vasculature of the AD brain. The applicant proposed to use Magnetic Resonance Angiography (MRA) to develop an in vivo noninvasive imaging method to identify the occlusions present in the AD brain. Dr. Cortes-Canteli has obtained ample experience with MRI techniques with the invaluable help of the Advanced imaging Unit at CNIC. Using the 7-Tesla MicroMR available at the Center, we optimized different brain imaging protocols to implement in our AD mouse models. One of them is the one proposed in the original application, MRA, but we have also used Arterial Spin Labeling (ASL) MRI to measure blood flow. Moreover, the applicant has taken advantage of the advanced imaging equipment available at CNIC and has also used Computed Tomography (CT) to analyze the mouse cerebral vasculature ex vivo. The results are expected to be of great importance since we will be able to identify and quantify the composition of the stalled vessels present in the AD brain through non-invasive imaging approaches, which will contribute to the advancement of diagnosing AD. This approach will not only identify when and where the vessel obstructions begin but will also identify the specific components of these occlusions. This in vivo system could be used in combination with other biomarkers to help identifying individuals at early stages of the disease. There is a need to develop early biomarkers for AD as well as individual biomarkers to identify the different pathological hallmarks present in this multifactorial disease. This will define different AD subtypes and will aid in matching patients groups with the most appropriate drugs. During the past few years, biomarkers for hallmarks such as amyloid, synaptic dysfunction, and brain atrophy have been developed. However, no biomarkers are yet available to identify the vessel occlusion that contributes and possibly precedes the chronic brain hypoperfusion and cerebrovascular dysfunction existent in AD. This in vivo system could be used in combination with other biomarkers and will help identifying individuals at early stages of the disease and improve the outcome of clinical trials since a better pre-selection of appropriate patient populations could be achieved.Aim 2- Analysis of direct thrombin inhibitors as a potential novel treatment for AD. The applicant proposed to test novel anticoagulant molecules as a potential treatment for AD. Transgenic AD mice have been treated with different doses of a direct thrombin inhibitor (DTI) and Dr. Cortes-Canteli has performed several analysis to measure amyloid pathology, neuroinflammation and synaptic dysfunction as planned. Moreover, taking advantage of the advanced imaging equipment for small animals located at CNIC, the applicant also evaluated the cerebral blood perfusion and neuronal function during anticoagulant treatment.This disease was discovered more than 100 years ago, but there is still no cure. The few current pharmacological approaches approved to treat this disorder are mainly cholinesterase inhibitors that have very modest impact on slowing the progression of the disease. Therefore, new therapeutic strategies to treat AD are sorely needed. Among others, anti-amyloid agents and tau-targeted treatment strategies are being actively investigated. However, given the complex nature of this disease, where dysregulation of different pathways are affected, a multidrug approach might prove more useful than a single one. The results obtained from this grant will demonstrate whether the use of already approved new anticoagulant drugs could be used as a novel therapeutic approach to treat one aspect of the vascular pathology present in AD. This approach would normalize the increased thrombosis rate found in the AD brain, hence improving cerebral blood flow, neuronal function, and survival. This therapeutic strategy could be a promising therapeutic approach to use in combination with others.The project has its own website within CNIC domain: https://www.cnic.es/en/node/8692. This website will be updated with the latest results as soon as they are accepted for publication. The ADvasculature project has been also mentioned in the 2015 CNIC Scientific Report (https://www.cnic.es/en/scientific-report - Translational Coordination. See also document attached), and will be mentioned in the 2016 one as well. Any questions regarding the ADvasculature project, please contact Dr. Marta Cortes-Canteli at mcortes@cnic.es. Related documents final1-scientificreport2015.pdf
