Elevated plasma biomarkers of inflammation in acute ischemic stroke patients with underlying dementia

The blood-brain barrier has been a hindrance to developing blood-based diagnostic tests for dementias, as it limits the appearance of brain biomarkers in the blood. Our aim was to see if the natural opening of the blood-brain barrier induced by ischemic stroke would increase serum levels of inflammatory biomarkers known to be elevated in the brains of patients with Alzheimer's disease and other neurodegenerative dementias.

Forty-three patients with acute ischemic stroke presenting to Stony Brook University Hospital were prospectively enrolled in the study. Eight of these patients were clinically diagnosed as having an underlying neurodegenerative dementia. Blood was drawn acutely within 72 h of stroke symptom onset, and serum levels of the classic inflammatory biomarkers, interleukin-6 (IL-6) and C-reactive protein (CRP) were measured, along with levels of S100B protein (S100B) and complement C3 (CC3).

Serum levels of IL-6 and CRP in patients with acute ischemic stroke and underlying dementia (AIS + D) were significantly higher (p = 0.002 and 0.003, respectively) than in patients with acute ischemic stroke alone (AIS). Serum levels of S100B and CC3 did not differ significantly between the groups.

This study supports the possibility that opening of the blood-brain barrier may enhance the blood appearance of brain tissue markers of inflammation associated with neurodegenerative dementia. Further study is warranted to test this possibility, given the recent emergence of methods to open the blood-brain barrier for diagnostic or therapeutic purposes.