BETHESDA, MD. (FRONTLINE MEDICAL NEWS) Cerebral vascular dysfunction exerts a significant negative influence on cognition, doubling the risk of dementia in old age and speeding the rate of cognitive decline.

These findings have been confirmed in a number of studies, and their advancement in both research and clinical arenas continues. But studies of the vascular conditions that affect cognition remain largely observational. Intervention trials are few and limited in scope. The dearth of animal models that express compromised cerebral vascular function has made conducting basic studies feel like wheels spinning in the mud.

According to investigators who discussed the problem at the recent Alzheimer’s Disease–Related Dementias 2016 Summit, sponsored by the National Institutes of Health, the situation calls for a targeted push to better understand vascular complications and their impact on cognition and the development of dementias – and a new, 5-year NIH research program aims to do just that.

M²OVE–AD: Molecular Mechanisms of the Vascular Etiology of Alzheimer’s Disease, is a $30 million initiative that brings together more than a dozen research teams. Investigators will employ new molecular profiling technologies and big data analytics to understand how vascular dysfunction influences the development of Alzheimer’s. The teams will collaborate on five different projects, each exploring a different facet of these complex processes, according to Dr. Suzana Petanceska, program director of the neuroscience division at the National Institute on Aging, Bethesda, Md., who shared her thoughts after the meeting.

“The central goal of the consortium is to generate a deeper understanding of the molecular mechanisms linking vascular risk factors, cerebrovascular disease, and Alzheimer’s, and to generate a new big-data resource that will aid the discovery of therapeutic targets for disease treatment and prevention and molecular signatures that can be used as biomarkers for disease risk,” Dr. Petanceska said in an interview.

Following a new trend of sharing Alzheimer’s research data across public and academic domains, data generated by this program will be made rapidly available to the greater research community. “Making these complex biological data sets available and usable by researchers other than the data generators is key to accelerating the pace at which the research community can generate new knowledge and replicate new findings. The M²OVE–AD initiative builds on the open-science approach established by the Accelerating Medicines Partnership – AD Program and Alzheimer’s Disease Neuroimaging Initiative (ADNI). By coordinating the experimental and analytical approaches the research teams will maximize the usability of the data generated on these projects.”

Five complementary projects comprise the consortium:

Integrative Translational Discovery of Vascular Risk Factors in Aging and Dementia

Researchers at the Mayo Clinics in Minnesota and Florida will collaborate with those at the Icahn Institute for Genomics and Multiscale Biology, New York, to explore how molecular networks influence vascular risk in normal aging, as well as in Alzheimer’s and other dementias.

The project’s goal is to understand how gender and the Alzheimer’s disease risk factor gene ApoE4 influence the molecular processes that lead to Alzheimer’s-related cerebral amyloid angiopathy (CAA).

CAA appears to be a key player in the progression of Alzheimer’s disease. The health of small vessels of the brain is important not only in age-related cognitive decline, but also in amyloid clearance. When amyloid collects in these vessels, it may cause a potentially self-sustaining loop of vascular injury and impaired amyloid clearance, which causes more intravascular amyloid deposition, more CAA, and increasing amyloid pathology.

The team intends to use genetic and expression profiling data from human brain and bloods samples, as well as existing molecular, clinical, and pathologic data in hopes of discovering therapeutic targets. The dynamic interaction between gender, apoE4 and aging and its impact on various AD pathologic and clinical traits will be explored in an array of existing and new animal models.

“Integrating the analysis of multidimensional human data with studies in animal models will accelerate the speed with which the findings can be translated to new interventions for treatment and prevention,” Dr. Petanceska said.

Interdisciplinary Research to Understand the Interplay of Diabetes, Cerebrovascular Disease and Alzheimer’s Disease

Type 2 diabetes mellitus and prediabetes metabolic abnormalities affect one-third of U.S. adults and the majority of persons aged 60 years and older. Diabetes is associated with a higher risk of the clinical manifestations of AD, including dementia and mild cognitive impairment. Hispanics in the United States have higher rates of diabetes, putting them at greater risk for developing Alzheimer’s. Investigators at Columbia University and SUNY Downstate Medical Center, both in New York, will examine the complex relationship between diabetes, cerebrovascular disease, and Alzheimer’s in a cohort of 200 middle-aged Hispanic participants, with either normal glucose metabolism, prediabetes, or type 2 diabetes; the subjects will be followed for 5 years with whole-brain magnetic resonance imaging and a variety of cognitive measures. The brain imaging will track AD-like functional and pathologic changes and vascular lesions.

In addition, the team will carry out molecular profiling of plasma samples collected in the same participants to identify metabolic and protein signatures that may predict clinical, pathologic, and physiologic outcomes related to Alzheimer’s and cerebrovascular disease.

In a companion study using mouse models with diabetes and Alzheimer’s pathology traits, the researchers will examine how the interaction between diabetes and Alzheimer’s pathology affects the structure and function of neural circuits important to learning and memory.

“This project is addressing two critical knowledge gaps,” Dr. Petanceska said. “The first is understanding the mechanisms by which dysregulated glucose metabolism impacts the onset and progression of pathologic changes in the course of the preclinical phase of Alzheimer’s disease; the second is understanding the molecular determinants of AD risk in Hispanics, a population with higher prevalence of diabetes and at greater risk for AD.”

The Role of Renin-Angiotensin-Endothelial Pathway in Alzheimer’s Disease

Researchers at Emory University, Atlanta, will focus on understanding the molecular mechanisms by which vascular dysfunction associated with high blood pressure affects the onset and progression of Alzheimer’s.

The research cohort comprises 160 subjects from the Emory Cardiovascular Biobank and Predictive Health Study – 80 with normal cognition and 80 with mild cognitive impairment – who will be followed for 2 years. Molecular data (genomic, epigenetic and metabolomic) combined with clinical data on the same subjects collected over 2 years, will be used to build a molecular network model of the interaction between vascular dysfunction and various Alzheimer’s disease traits.

Parallel studies in a rat model that uniquely exhibits human-like AD neuropathology will help uncover the temporal relationship between vascular dysfunction and AD and examine the potential of the molecular regulators of vascular function, such as the renin-angiotensin system, as therapeutic targets for AD. The goal is to characterize this pathway as a therapeutic target.

Metabolic Signatures Underlying Vascular Risk Factors for Alzheimer’s-Type Dementias

Teams at Duke University, Durham, N.C., and the University of Pennsylvania, Philadelphia, will carry out extensive profiling of plasma samples from 900 ADNI participants and from participants in the Duke University MURDOCK Memory and Cognitive Health Study in search for lipid metabolites that are associated with cardiovascular disease and cognitive change. These lipidomic profiles will be integrated with the vast array of clinical and other molecular data available for these participants to identify molecular signatures that may be used to differentiate among various risk-factor types of AD.

In addition, in a subset of subjects, the team will compare the lipidomic profiles between plasma and cerebrospinal fluid; this will enable the team to test hypotheses about the role of systemic vascular and metabolic factors on cognitive aging and AD.

Cerebral Amyloid Angiopathy and Mechanisms of Brain Amyloid Accumulation

Investigators at Massachusetts General Hospital, Boston, will investigate the molecular underpinnings of CAA and its impact on Alzheimer’s disease. Employing a mouse model and human subjects with CAA, the study will explore this cycle of progressive amyloid deposition and brain injury. The team’s approach combines noninvasive detection and analysis of human CAA, real-time measurement of vascular structure and physiology in living transgenic mouse models, and molecular analysis of gene expression in brain microvessels. Ultimately, the team hopes to identify candidate therapies with which could block it.

“This highly multidisciplinary investigation into how the vascular effects of amyloid at the molecular, single-blood vessel, and whole-brain levels influence the clinical disease promises to deliver new, well-characterized therapeutic targets for disease prevention,” Dr. Petanceska said.

She predicted that the wide-ranging projects of the M²OVE–AD consortium will bring invaluable understanding to an enormously important, but still unexplored, aspect of Alzheimer’s pathology.

“We hope that this large-scale team science effort will generate an in-depth understanding of how vascular and metabolic factors contribute to neurodegenerative changes that result in cognitive decline and dementia and that the data and knowledge generated by this program will be the basis for developing effective interventions for disease treatment and prevention.”

On Twitter @Alz_Gal


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