Arterioles in cerebral amyloid angiopathy and vascular dementia.

Background: Small cerebrovascular lesions are one of the most important factors in cerebral amyloid angiopathy (CAA) and vascular dementia (VaD). We analyzed the difference of arteriolar pathology between CAA patients (CAAs) and vascular dementia patients without CAA (VaDs).

Methods: Ten deceased CAAs and twelve deceased VaDs were available for this study. Five deceased patients without known cerebrovascular diseases served as controls. These patients were all autopsy cases. All transversely cut arterioles in the gray matter and white matter with an external diameter equal to or larger than 30 microm and with a maximum of 300 microm were examined. The internal and external diameters of arterioles were measured.

Results: The external diameter of gray matter arterioles in the CAAs was significantly greater than in controls. In gray matter arterioles, the diameter of the lumen in VaDs was markedly smaller than in the CAAs, whereas there was no significant difference between CAAs and controls. CAAs and VaDs may cause remarkable thickening of the arteriolar walls in either white matter or gray matter. The sclerotic index of arterioles in VaDs was significantly greater than in CAAs and controls.

Conclusions: Stenosis of arterioles occurred in both CAA and VaD, but the tendency was greater in VaD. Arterioles of CAA were also expanded in gray matter, which may be related to lobar hemorrhage. The loss and/or degeneration of vascular smooth muscle cells was predominant in CAA, while the over-proliferation of vascular smooth muscle cells was greater in VaD.