Alzheimer’s disease (AD) consists of a continuum from an asymptomatic preclinical form to the disease objectivated by cognitive and memory tests. Differential diagnosis is difficult during the asymptomatic preclinical phase of the pathology. Alzheimer's disease is defined by the association of a progressive dementia syndrome and of two main characteristic brain molecular lesions: extracellular senile plaques composed primarily of amyloid peptides, and neurofibrillary tangles (NFTs) composed of hyperphosphorylated Tau aggregates. Recently a major role for extracellular pathological forms of Tau proteins, Tau oligomers, has been shown in the propagation mechanism of the pathology within the brain by contaminating neuron after neuron. Cognitive impairment becomes manifest when lesions reach the hippocampus, with abundant neocortical Tau inclusions and extracellular amyloid deposits. The development of new therapeutic strategies to eliminate the pathological forms of tau protein requires their evaluation during preclinical and clinical trials in well-characterized patient groups. Furthermore, early diagnosis is required for implementing appropriate therapy. Our project concerns the development of nuclear imaging tools to detect the early abnormal forms of Tau in the human brain with Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) in order to improve the diagnosis and the follow-up of AD hallmarks. Our strategy is to develop radiolabeled nanobodies (Nbs) directed against the oligomeric form of pathologic Tau protein. Nbs represent the smallest possible (15 kDa) functional immunoglobulin-like antigen-binding fragments, possess nanomolar affinity and are by nature present in camelids. We produced a Nb (2C5), with both good affinity and specificity for human tau protein oligomers. We significantly increased the passage of the blood-brain barrier (BBB) from 2C5, as demonstrated in vitro in an artificial BBB model, by improving its isolectric point and lipophilicity and by associating it with peptides facilitating the BBB crossing. The purpose of our project is to validate in vivo this new ligand of early pathological forms of tau. The vectorized Nb will be radiolabeled, with 99m technetium (99mTc) by coordination according to the method developed in the laboratory for other Nbs. Binding properties of this radioligand will be evaluated in vitro as previously for 2C5. Then, its biodistribution will be assessed in wild-type mice to determine the radiotracer retention in the various organs. The radiotracer will then be validated in transgenic mice along SPECT imaging studies. Secondarily, the development of radiolabeling of this Nb with 68 Gallium (68Ga) will be carried out and pharmacokinetic and PET imaging studies conducted as for the 99mTc-ligand. The 99mTc and 68Ga radiolabeled ligands will finally be compared to 18F-AV1451, the most currently used NFTs radiotracer: The main goal of this project is to provide a radiotracer specific for abnormal forms of Tau usable in Nuclear Medicine facilities for SPECT and/or PET imaging.

Single domain antibodies (sdAb or nanobodies) based imaging agent directed at the inflammatory marker Vascular Cell Adhesion Molecule 1 (VCAM-1) have recently been validated by the LRB (partner 1) for the non-invasive nuclear imaging of atherosclerosis and liver inflammation in mice. The lead compound (cAbVCAM1-5) has been produced according to good manufacturing practice and a phase I/II clinical trial is underway at Grenoble-Alpes University Hospital. The aim of the present project is to further evaluate its capabilities using preclinical mice models in order to pave the way of future clinical evaluations. To fulfill this objective, we will evaluate its ability to detect and quantify chronic inflammation in various pathological settings and organs. Moreover, we will evaluate the potency of anti-VCAM-1 sdAb for magnetic resonance imaging (MRI), as an alternative to nuclear imaging, using biodegradable microparticles developed by partner 4 (PhIND). cAbVCAM1-5 will therefore be evaluated in a mouse model of spondyloarthritis in collaboration with the T-Raig team (Lab TIMC, partner 2), in mice models of myocardial infarction with HP2 laboratory (partner 3) and in mice models of neuroinflammation in collaboration with PhIND. Upon completion of this research project, the consortium will have investigated the potential of the anti-VCAM-1 sdAb in 3 pathological settings that could potentially benefit from improved diagnostic and prognostic imaging biomarkers for the management of patients. The results will therefore allow determining relevant strategies for the evaluation of this novel imaging agent, in particular for the design of phase II clinical trials. Moreover, it will provide a better understanding of the tissue and subcellular distribution of this imaging agent, and will explore the possibility to extend its field of application using MRI as a second imaging modality.

To date, early warning signs of acute decompensation of heart (ADHF) are not detected and medical treatment is adjusted only to the apparition of symptoms leading to hospitalization. 40% of patients hospitalized twice in a year for ADHF die in the following year. Existing devices - implanted or not - allow to acquire relevant physiological parameter(s) whose analysis can lead to early detection. However, these devices do not respond efficiently to economic medical issues or require complex implantation. Some of these devices only consider a single biomarker whereas the HF syndrome is mutliparametric. Some devices are comparable to our proposal in terms of parameters taken into account, but they are only relevant for a small proportion of the patients undergoing heart failure, those equipped with cardio defibrillators. Over this project, our final aim is to develop a fully-implantable and fully-integrated device able to track various parameters involved in the ADHF process with the aim of providing early detection. Examples include heart rate (HRV) and respiratory rate variability, cardiac (S1, S3) and pulmonary heart sounds as well as patient activity and position. The originality of our approach lies in the choice of a gastric implantation site. This implantation site has never been used before and opens a promising exploratory field associated with new potentially relevant parameters in the follow-up of HF. The added value of the gastric implantation site also lies in the compatibility with an endoscopic route thus minimizing complications and time of hospitalization. This 3-year project is structured to validate a data extraction process and demonstrate, through a preclinical study, the ability to track specific ICID biomarkers through (1) a multimodal device implanted in the stomach of healthy or HF pigs in ambulatory conditions and through (2) an appropriate treatment of cardiac and respiratory signals. This project faces a certain number of technical and scientific challenges: denoising of signals, pre-clinical model of adapted HF. Each of these challenges is associated with well identified risks for which we already propose adapted fallback solutions. The consortium is composed of four complementary partners; 3 laboratories and a private company. The industrial partner will bring its knowledge in the fields of electronics and mechatronics and will ensure the valorization of the results. The hospital partner (LRB) will bring its expertise to ensure the relevance of selected pre-clinical models and selected pathophysiological parameters. Finally, the scientific partners (TIMC, LTSI) will bring their skills in the field of cardio-respiratory parameters monitoring techniques and associated information processing methods.

With 17.6 million of individuals / year, cardiovascular diseases represent the first cause of death in the world, the majority of those deaths being attributed to coronary artery disease (CAD). The underlying mechanism of CAD is the development of atherosclerotic plaques within the wall of coronary arteries. General risk factors that allow initial risk stratification are well known, but it remains a major challenge to identify individual patients before the occurrence of acute clinical events. It is the realization that so called ‘high-risk’ or ‘vulnerable’ atherosclerotic plaques are responsible for the majority of these events, that has motivated the development of diagnostic strategies to predict in an early stage whether a specific patient will develop a life-threatening event or not. For one, molecular imaging has emerged as a tool to identify and visualize biological aspects implicated in atherosclerotic plaque vulnerability. The final goal of this project is to develop and translate to the clinic an imaging agent dedicated to the detection of vulnerable plaques in nuclear medicine departments. The term ‘vulnerable plaque’ is used to refer to atherosclerotic lesions that are responsible for life-threatening thrombotic complications. As rupture of thin-capped fibro-atheroma (TCFA) with large lipidic and necrotic cores and intense inflammatory process is the major underlying substrate, most anatomic and molecular imaging and therapeutic strategies are focusing on this specific lesion type. However, other plaque types such as eroded lesions can also give rise to thrombotic events. The prevalence of these lesions has increased so that they are now considered to be responsible for 30-40% of acute coronary syndromes (ACS). In order to identify all high-risk patients, the ideal imaging tracer should thus be able to detect both types of vulnerable lesions. Indeed, an imaging agent dedicated to non-invasive imaging of atherothrombosis that could accurately detect high risk TCFA and eroded atherosclerotic plaques and thereby enable preventive therapy to be implemented to avoid a heart attack would address a major unmet clinical need. More importantly, it will also greatly enhance the quality of at-risk patient care and treatment. Pro-thombotic factors are expressed in both main types of vulnerable lesions (TCFA and eroded lesions), and are key drivers of the thrombotic process that is responsible for acute coronary symptoms. They therefore constitute attractive targets for atherothrombosis imaging. Two of the partners have previously developed a first generation of single-domain antibody (sdAb) derived imaging agents targeting the inflammatory process that characterizes TCFA, that is currently under clinical transfer. The aim of this project is to develop and fully characterize a second generation of sdAb-derived atherosclerosis imaging agents with potentially broader application for atherothrombosis. To fulfill this objective they are collaborating with a third partner that is an expert in hematology. the project will be subdivided into 8 tasks, from the generation of the sdAb to their in vivo evaluation in mice using state of the art preclinical nuclear imaging systems.