Angiogenesis, the growth of new blood vessels, is a complex process of successive stages, in which numerous cell types and signal molecules play changing roles as budding and growth of the new vessel progresses. Angiogensis becomes less effective with age, for reasons that remain unclear. Here, researchers note that increased levels of PLGF, a companion signal molecule to VEGF in regulating angiogenesis, are associated with poor outcomes in cerebral small vessel disease, a dysfunction of the smaller blood vessels in the brain. They hypothesize that an increased effort to conduct angiogenesis, likely unsuccessful given the noted decline in capillary density with age, is a reaction to the damage found in these aged, inflamed blood vessels.
Cerebral small vessel disease, a common disease marked by damage to the cells lining the blood vessels in the brain, is a major driver of cognitive problems and dementia in older adults. However, it can be difficult for doctors to determine whether a patient's cognitive impairments stem predominately from Alzheimer's disease or vascular problems, the two most common causes of dementia. In new research, scientists found that patients with higher levels of placental growth factor (PLGF) - a key molecule involved in the formation of new blood vessels, or angiogenesis - were more likely to have cognitive impairment or evidence of brain injury.
Researchers identified signaling involved in angiogenesis as potential biomarkers, theorizing that the body may respond to damaged small blood vessels in the brain with intensified efforts to grow more. For this study, researchers focused on just one of those signals, PLGF, which has previously been associated with cerebral blood flow regulation. Data had also suggested this may be a useful biomarker for identifying patients with cognitive impairment and dementia due to vascular brain injury.
335 patients underwent brain imaging, cognitive testing and blood collection. Researchers found those in the top quartile for PLGF measurement were three times as likely to have cognitive impairment or dementia compared to those in the bottom quartile. Every unit increase in total PLGF in the bloodstream was also associated with a 22% increase in the likelihood of having cognitive impairment and a 16% increase in the likelihood of having neuroimaging evidence of cerebral small vessel disease.