Biomarker identified that helps diagnose cause of cognitive decline
It can be difficult to determine whether cognitive decline in older adults is caused by vascular problems or dementia. New research has now identified a biomarker associated with the vascular causes of cognitive impairment that may assist with differentiating the two.
Cerebral small vessel disease causes progressive damage to the cells lining the small blood vessels of the brain and is known to be a significant contributor to cognitive impairment and dementia. The damage observed in the cerebral blood vessels in vascular conditions, is similar to that seen in Alzheimer’s disease, making it difficult to ascertain the cause.
While doctors rely on magnetic resonance imaging (MRI) and computerized axial tomography (CAT) scans to differentiate between vascular damage and Alzheimer’s disease, a certain amount of speculation is involved. However, new research has identified a diagnostic biomarker that may reduce some of the guesswork.
The research, led by the University of California, Los Angeles (UCLA), focused on the body’s formation of new blood vessels from existing ones, a process called angiogenesis. Angiogenesis involves signaling networks among and within endothelial cells, the main type of cells found in the lining of blood vessels.
Researchers theorized that the body tries to repair damaged cerebral small blood vessels by boosting angiogenesis. They focused on placental growth factor (PlGF), a key molecule in the angiogenic process known to be associated with regulating cerebral blood flow.
As part of the study, 335 participants underwent brain imaging with MRI and cognitive testing. Blood samples were taken that included measurement of PlGF levels.
The results showed that participants with cognitive impairment and brain imaging consistent with cerebral small vessel disease also had high plasma levels of PlGF. Those in the top quartile for PlGF levels – above 75% of people who were tested – were three times as likely to have cognitive impairment or dementia than those in the bottom quartile.
Identifying PlGF as a biomarker for the contribution of vascular disease to cognitive decline is an important step towards distinguishing this kind of cognitive impairment from that caused by Alzheimer’s disease.
“The addition of a blood-based biomarker that is associated with the traditional measures of vascular injury could allow a [healthcare] provider to be able to distinguish the patient that has Alzheimer’s-predominant dementia versus a significant vascular contribution,” said Jason Hinman, MD, PhD, lead author of the study. “Right now, it’s kind of the clinician’s best guess. This work can directly inform this diagnostic decision."
The study was published in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association.