Clinical diagnosis and successful treatment of inflammatory cerebral amyloid angiopathy

[A subacute dementia: Inflammatory cerebral amyloid angiopathy]

We report a case of inflammatory cerebral amyloid angiopathy (CAA) that led to rapid cognitive decline, seizures, visual hallucinations, hyperproteinorrachia and right hemispheric leukopathy. Brain biopsy gave the diagnosis of CAA. Although no inflammatory infiltrate was found in the biopsy sample, corticosteroids led to a regression of the radiological lesions without significant clinical improvement. CAA is a rare disease, defined by lesions of classical cerebral amyloid angiopathy and perivascular infiltrates in contact with the affected vessels. In cases of rapidly progressive dementia associated with leukopathy, inflammatory amyloid angiopathy should be considered as cognitive disorders may improve after immunosuppressive therapy.

[Cerebral amyloid angiopathy is difficult to diagnose in the intensive care unit]

Cerebral amyloid angiopathy is a common cause of intracerebral haemorrhage in elderly patients. The diagnosis of cerebral amyloid angiopathy is based on the Boston criteria combining clinical and radiological criteria with no other cause of intracerebral haemorrhage. We describe the case of a 60-year-old female admitted to the intensive care unit for agitation and spatial disorientation. She had multiple intracerebral haematomas on brain CT scan. Typical cerebral microbleeds using MRI and the absence of other cause of intracerebral haemorrhage argued in favour of the diagnosis of cerebral amyloid angiopathy. The patient outcome was favourable with a discharge from the intensive care unit on day 16.

Amyloid-β contributes to blood-brain barrier leakage in transgenic human amyloid precursor protein mice and in humans with cerebral amyloid angiopathy

BACKGROUND AND PURPOSE

Cerebral amyloid angiopathy (CAA) is a degenerative disorder characterized by amyloid-β (Aβ) deposition in the blood-brain barrier (BBB). CAA contributes to injuries of the neurovasculature including lobar hemorrhages, cortical microbleeds, ischemia, and superficial hemosiderosis. We postulate that CAA pathology is partially due to Aβ compromising the BBB.

METHODS

We characterized 19 patients with acute stroke with "probable CAA" for neurovascular pathology based on MRI and clinical findings. Also, we studied the effect of Aβ on the expression of tight junction proteins and matrix metalloproteases (MMPs) in isolated rat brain microvessels.

RESULTS

Two of 19 patients with CAA had asymptomatic BBB leakage and posterior reversible encephalopathic syndrome indicating increased BBB permeability. In addition to white matter changes, diffusion abnormality suggesting lacunar ischemia was found in 4 of 19 patients with CAA; superficial hemosiderosis was observed in 7 of 9 patients. Aβ(40) decreased expression of the tight junction proteins claudin-1 and claudin-5 and increased expression of MMP-2 and MMP-9. Analysis of brain microvessels from transgenic mice overexpressing human amyloid precursor protein revealed the same expression pattern for tight junction and MMP proteins. Consistent with reduced tight junction and increased MMP expression and activity, permeability was increased in brain microvessels from human amyloid precursor protein mice compared with microvessels from wild-type controls.

CONCLUSIONS

Our findings indicate that Aβ contributes to changes in brain microvessel tight junction and MMP expression, which compromises BBB integrity. We conclude that Aβ causes BBB leakage and that assessing BBB permeability could potentially help characterize CAA progression and be a surrogate marker for treatment response.