ARIA-E refers to cerebral edema, involving the breakdown of the tight endothelial junctions of the blood-brain barrier and subsequent accumulation of fluid.[3] In a double-blind trial of the humanised monoclonal antibody solanezumab (n = 2042), sixteen patients (11 taking the drug, 5 taking a placebo), or 0.78% developed ARIA-E. A further 7 patients developed ARIA-E during an open-label extension of the trial.[4]
The effect of ARIA-E depends on the severity and location of the edema. Symptoms may include headache, changes in mental state, confusion, vomiting, nausea, tremor and gait disturbances.[4]
ARIA-H
ARIA-H refers to cerebral microhaemorrhages (mH), small haemorrhages on the brain,[5] often accompanied by hemosiderosis.[1] mH are usually seen as small, round and low intensity lesions and are small haemosiderin deposits. Some studies define mH as being less than or equal to 10mm, while others define the cut-off as ≤ 5mm.[1] The prevalence of mH in healthy elderly people is approximately 6%, but this value increases to between 50% and 80% in elderly people with cerebrovascular disease.[6]
Mechanism of action
MRI scans of the human brain, examples of ARIA highlighted in blue: Left: ARIA-E with sulcal effusion (FLAIR sequence) Middle: ARIA-H with multiple microbleeds (T2* weighted) Right: ARIA-H with superficial siderosis (T2* weighted)
Two non-exclusive mechanisms have been postulated. Firstly, in the context of aging and neurodegeneration, the integrity of the blood-brain barrier (BBB) can become compromised, resulting in increased permeability. Notably, amyloid plaques have been hypothesized to counteract this BBB leakage.[7] However, upon the administration of antibodies, these plaques are targeted and subsequently eliminated, potentially uncovering the occurrence of micro-hemorrhage [8][9] Secondly, an alternate perspective posits that the introduction of antibodies into the bloodstream triggers an immune-inflammatory response as part of the treatment regimen. This orchestrated immune reaction might inadvertently precipitate micro-hemorrhages.[10]
FLAIR hyperintensity 5 to 10cm, or more than 1 site of involvement, each measuring < 10cm
FLAIR hyperintensity measuring > 10cm, often with significant subcortical white matter and/or sulcal involvement. One or more separate sites of involvement may be noted.
↑ Atwood, Craig S.; Bowen, Richard L.; Smith, Mark A.; Perry, George (September 2003). "Cerebrovascular requirement for sealant, anti-coagulant and remodeling molecules that allow for the maintenance of vascular integrity and blood supply". Brain Research Reviews. 43 (1): 164–178. doi:10.1016/S0165-0173(03)00206-6.
↑ Hansen, Scott B. (18 July 2023). "Cholesterol's Function and Origin in the Alzheimer's Disease Brain". Journal of Alzheimer's Disease. 94 (2): 471–472. doi:10.3233/JAD-230538.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.