Open AccessBiomarker potential of brain‐secreted extracellular vesicles in blood in Alzheimer's disease
Author(s) -
Badhwar AmanPreet,
Haqqani Arsalan S.
Publication year - 2020
Publication title -
alzheimer's and dementia: diagnosis, assessment and disease monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.497
H-Index - 37
ISSN - 2352-8729
DOI - 10.1002/dad2.12001
Subject(s) - research centre , library science , brain research , gerontology , political science , medicine , psychology , neuroscience , computer science
Brain cells secrete extracellular microvesicles (EVs) that cross the blood‐brain barrier. Involved in cell‐to‐cell communication, EVs contain surface markers and a biologically active cargo of molecules specific to their tissue (and cell) of origin, reflecting the tissue or cell's physiological state. Isolation of brain‐secreted EVs (BEVs) from blood provides a minimally invasive way to sample components of brain tissue in Alzheimer's disease (AD), and is considered a form of “liquid biopsy.” Methods We performed a comprehensive review of the PubMed literature to assess the biomarker and therapeutic potential of blood‐isolated BEVs in AD. Results We summarize methods used for BEV isolation, validation, and novel biomarker discovery, as well as provide insights from 26 studies in humans on the biomarker potential in AD of four cell‐specific BEVs isolated from blood: neuron‐, neural precursor‐, astrocyte‐, and brain vasculature–derived BEVs. Of these, neuron‐derived BEVs has been investigated on several fronts, and these include levels of amyloid‐β and tau proteins, as well as synaptic proteins. In addition, we provide a synopsis of the current landscape of BEV‐based evaluation/monitoring of AD therapeutics based on two published trials and a review of registered clinical trials. Discussion Blood‐isolated BEVs have emerged as a novel player in the study of AD, with enormous potential as a diagnostic, evaluation of therapeutics, and treatment tool. The literature has largely concentrated on neuron‐derived BEVs in the blood in AD. Given the multifactorial pathophysiology of AD, additional studies, in neuron‐derived and other brain cell–specific BEVs are warranted to establish BEVs as a robust blood‐based biomarker of AD.