The
discovery of early plasma biomarkers for Alzheimer’s disease could transform
outcomes by enabling patients to begin treatment early.
Canadian researchers have identified two biomarkers which were able to predict Alzheimer’s disease (AD) five years before its onset. Their discovery could revolutionise how, and at what stage of disease, patients are diagnosed.
Typically,
AD is diagnosed through a series of psychometric tests assessing cognitive
function, brain imaging and cerebrospinal fluid analysis. However, these tests
have their limitations: “The lumbar puncture is invasive, while brain imaging
is expensive and not 100 percent reliable. This complicates regular follow-up,”
explained Professor Charles Ramassamy of the Institut National de la Recherche
Scientifique (INRS), Canada, who directed the researchers.
Moreover,
people with the disease are often diagnosed at a late stage of the disease when
there is too much damage to reverse. “We need to find more and more early
markers so we can act as soon as possible. When the disease is symptomatic,
there is little, if any, way back,” he added.
In their
study, the researchers focused on sporadic AD, the most common form of the
disease, which is primarily caused by the expression of the ε4 variant of the
APOE gene that encodes apolipoprotein. They analysed blood samples
collected as part of the Canadian Study of Health and Aging (CSHA). The
population studied consisted of patients with cognitive problems, but not
suffering from dementia, only some of whom developed AD.
The
scientists discovered that in patients who developed AD five years later, the
ratio between pentraxin‐2 and α‐synuclein expressed in the extracellular
vesicles circulating in their blood stream varied from those who did not
develop the disease. As a result, they concluded that the
pentraxin‐2/α‐synuclein ratio could serve as a useful early biomarker for AD
susceptibility. Extracellular vesicles are pockets that are naturally released
by all cells in the body and play an essential role play an essential role in
the crosstalk between the brain and the periphery.
Professor
Ramassamy said he now hopes to analyse a larger population with pre- and
post-disease samples to determine the progression of markers after the onset of
symptoms. He added that their research on the markers located in the vesicles
could enable the study of other diseases, such as vascular dementia.
The
study was published in Alzheimer’s & Dementia:
Translational Research & Clinical Interventions (TRCI).
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