Immune activation in amyloid-ß-related angiitis correlates with decreased parenchymal amyloid-ß plaque load.

BACKGROUND: Primary angiitis of the central nervous system (PACNS) is a rare but serious condition. A fraction of patients suffering from PACNS concurrently exhibit pronounced cerebral amyloid angiopathy (CAA) which is characterized by deposits of amyloid-ß (Aß) in and around the walls of small and medium-sized arteries of the brain. PACNS with CAA has been identified as a distinct disease entity, termed Aß-related angiitis (ABRA). Evidence points to an immune reaction to vessel wall Aß as the trigger of vasculitis. OBJECTIVE: To investigate whether the inflammatory response to Aß has (1) any effect on the status of immune activation in the brain parenchyma and (2) leads to clearance of Aß from brain parenchyma. METHODS: We studied immune activation and Aß load by quantitative immunohistochemical analysis in brain parenchyma adjacent to affected vessels in 11 ABRA patients and 10 matched CAA controls. RESULTS: ABRA patients showed significantly increased immune activation and decreased Aß loads in the brain parenchyma adjacent to affected vessels. CONCLUSION: Our results are in line with the hypothesis of ABRA being the result of an excessive immune response to Aß and show that this can lead to enhanced clearance of Aß from the brain parenchyma by immune-mediated mechanisms.

[A potential neuroprotective and synaptic plasticity mechanism induced by estradiol through PI3K/GSK3beta in cerebral ischaemia]. / Mecanismo potencial de neuroprotección y plasticidadsináptica inducidas por el estradiol a través dePI3K/GSK3beta en la isquemia cerebra.

AIM: To review the basic molecular mechanisms that are triggered by neuroactive steroids related to protection and plasticity, and their possible therapeutic application in cases of cerebral ischaemia. DEVELOPMENT: The term 'neuroprotection' embraces a series of strategies and effects that are aimed at preventing, impeding or delaying anomalies in the functioning of the central nervous system. The neuroactive steroids, and particularly estradiol, have been widely reported owing to their neuroprotective action because they give rise to a wide range of cell signals and generate effects in genes by means of canonical pathways or through non-conventional mechanisms that are involved in neuronal survival, dendritogenesis and synapse remodelling. Thus, neuroactive steroids become an important long-term protective therapeutic alternative due to the fact that such effects converge on neuronal plasticity. CONCLUSIONS: Further work needs to be carried out to study the mechanisms of action of neuroactive steroids, especially the non-conventional ones, which involve proteins such as GSK-3beta and beta-catenin. These proteins are involved in the functions of synaptic plasticity and survival, and play a crucial role in maintaining and recovering the functional integrity of the brain after the appearance of the lesions caused by cerebral ischaemia.