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Título

An updated non systematic review on Cerebral amyloid angiopathy (CAA)

Resumo

Introduction: Cerebral amyloid angiopathy (CAA) is described as the accumulation of amyloid fibrils on the walls of blood vessels of the parenchyma of the central nervous system (CNS) and leptomeninges. Due to abnormal production or impaired clearance of the amyloid beta protein, structural changes in the vessels are lead, causing ischemic lesions and intracerebral hemorrhages (ICH) owing to small vessels fragility. Objectives: To describe the pathophysiology, criteria diagnosis and progression of CAA. Methods: Non systematic review in the Pubmed, Lilacs and Scielo databases, selecting articles in english, published from 2020 to 2022. Results: The pathophysiological progression of CAA remains uncertain, but has a strong contribution of a genetic component (APOE 2 and 4), related to changes in the astrocitarian reactivity and deficit of solubility factors. In addition, the impairment of perivascular spaces on the blood-brain barrier (BBB) or lymphatic system, accumulation of amyloid beta proteins, in the integrity of BBB by the loss of proteins on tight joints, leads to inflammatory effects by oxidative stress, which alters the permeability of the BBB and promotes toxicity and changes in vessel structure. Currently, the management of CAA remains focused in the prevention of recurrent ICH episodes, and the protocols for diagnosis still lack padronization – there is no consensus in the meanings of CAA’s neuropathology. Also, a definitive diagnosis can only be confirmed via postmortem examination of the brain. Thus, to identify possible CAA patients, the Boston criteria was developed as a combination of clinical, pathological, and radiographic criteria that uses MRI findings, classifying the results in “possible” and “likely”. According this criteria, the analyzed aspects of the MRI are strictly lobar cerebral microhemorrhages (small cerebral hemorrhages restricted to the cortical and subcortical regions of the brain), and superficial cortical siderosis (deposition of blood degradation products in the cortical sulci over the convexity of the cerebral hemispheres). The use of this criteria, in synthesis, can improve the chances of obtaining a diagnosis during the patient’s lifetime. Conclusions: The poor understanding of the disease mechanisms reflects the lack of therapies able to limit the disease progression. The combination between experimental results and clinical data from large observational studies are mandatory to its understanding.