Development of a neuroimaging biomarker of the pro‐coagulant state in Alzheimer’s disease: The BioClotAD Project

Abstract

AbstractBackgroundAlzheimer’s disease (AD) is the most common form of dementia1. Its multifactorial profile includes a strong vascular factor, partially driven by an early haemostatic dysregulation. Accordingly, fibrin, the main protein component of blood clots, is significantly increased in AD‐patients’ brains2. Furthermore, amyloid‐β contributes to this process by interacting with fibrin and producing degradation‐resistant clots3. Consequently, this pro‐thrombotic milieu intensifies hypoperfusion, neurodegeneration and blood‐brain barrier (BBB) disruption4, but it does not affect all patients. Therefore, early detection of these phenomena would be invaluable to identify patients likely to benefit from anticoagulant therapies5. Therefore, the BioClotAD Project aims to develop an imaging biomarker based on a fibrin binding probe (FBP)6 to non‐invasively identify AD’s pro‐coagulant state.MethodBioClotAD involves four partners in three European countries with complementary expertise. To optimize and test FBP we use extensive in vitro, ex vivo and in vivo assays, including AD animal models and human AD samples. Our project is comprised of three blocks: 1) Testing the FBP to in vivo detect the cerebral occlusions by nuclear imaging. 2) Detecting fibrin deposits inside the brain parenchyma with FBP coupled to a transferrin receptor antibody (FBP‐TfR) to facilitate BBB crossing7. FBP‐TfR will be labelled for optical and nuclear imaging. 3) Validating the most promising FBP probes in frozen brain samples of AD patients by autoradiography or fluorescence microscopy.ResultBioClotAD provides feasible neuroimaging strategies to in vivo detect the fibrin cerebral accumulation of AD models and identify the specific regional distribution in the brain. Our project will set the basis for future clinical trials on neuroimaging of the cerebral fibrin accumulation in AD.ConclusionBioClotAD neuroimaging biomarkers will allow the early detection of the pro‐thrombotic state in AD, opening a window of opportunity to delay the disease progression by personalized anticoagulant therapies. Funding: EU Joint Programme – Neurodegenerative Disease Research (JPND)