Leakage in blood-brain barrier discovered in patients with early Alzheimer's

Individuals with early forms of Alzheimer’s disease (AD) were found to have leakage in the blood-brain barrier (BBB), according to a recent study published in Radiology, and that leakage may be “a key mechanism in the early stages of the disease.”

Walter H. Backes, PhD, of the Maastricht University Medical Center in Maastricht, the Netherlands, and colleagues used contrast-enhanced MRI on 16 patients with early AD and 17 age-matched control subjects. The BBB leakage rate was much higher in the total gray matter and cortex of patients with AD than in the control subjects, the authors found. The 16 patients had a higher volume fraction of the leaking brain tissue in their gray matter, white matter, deep gray matter, and cortex.

“Blood-brain barrier leakage means that the brain has lost its protective means, the stability of brain cells is disrupted and the environment in which nerve cells interact becomes ill-conditioned,” Backes said in a statement. “These mechanisms could eventually lead to dysfunction in the brain.”

The authors added that they were confident the BBB leakage did not originate from vascular abnormality, because adding diabetes and other “noncerebral vascular diseases” to the model did not impact the results of their research.

Backes et al. also said they were able to rule out other potential explanations for the leakage.

“The BBB impairment did not fully originate from vascular abnormality, because adding diabetes and other noncerebral vascular diseases to the analysis model did not change the results,” the authors wrote in the study. “This suggested that the BBB impairment stemmed from the AD abnormality instead of from vascular comorbidities.”

The authors also noted that their study had potential limitations. The group size was small, for example, and the diagnosis of each patient was not confirmed at a neuropathologic examination.