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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: ATP Binding Cassette Transporter 1, Animals, Astrocytes, Blood-Brain Barrier, Brain Injuries, Cells, Cultured, Disease Models, Animal, Immunohistochemistry, Infarction, Middle Cerebral Artery, Insulin-Like Growth Factor I, Male, Matrix Metalloproteinase 9, Mice, Mice, Knockout, Mice, Transgenic, Stroke, Treatment Outcome, White Matter.
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Does deficiency of brain ATP-binding cassette transporter A-1 exacerbate blood-brain barrier and white matter damage after stroke? Context: The ATP-binding cassette transporter A-1 (ABCA1) gene is a key target of the transcription factors liver X receptors. Liver X receptor activation has anti-inflammatory and neuroprotective effects in animal ischemic stroke models. Here, we tested the hypothesis that brain ABCA1 reduces blood-brain barrier (BBB) and white matter (WM) impairment in the ischemic brain after stroke. Adult brain-specific ABCA1-deficient (ABCA1(-B/-B)) and floxed-control (ABCA1(fl/fl)) mice were subjected to permanent distal middle cerebral artery occlusion and were euthanized 7 days after distal middle cerebral artery occlusion. Functional outcome, infarct volume, BBB leakage, and WM damage were analyzed. Compared with ABCA1(fl/fl) mice, ABCA1(-B/-B) mice showed marginally (P=0.052) increased lesion volume but significantly increased BBB leakage and WM damage in the ischemic brain and more severe neurological deficits. Brain ABCA1-deficient mice exhibited increased the level of matrix metalloproteinase-9 and reduced the level of insulin-like growth factor 1 in the ischemic brain. BBB leakage was inversely correlated (r=-0.073; P<0.05) with aquaporin-4 expression. Reduction of insulin-like growth factor 1 and aquaporin-4, but upregulation of matrix metalloproteinase-9 expression were also found in the primary astrocyte cultures derived from ABCA1(-B/-B) mice. Cultured primary cortical neurons derived from C57BL/6 wild-type mice with ABCA1(-B/-B) astrocyte-conditioned medium exhibited decreased neurite outgrowth compared with culture with ABCA1(fl/fl) astrocyte-conditioned medium. ABCA1(-B/-B) primary cortical neurons show significantly decreased neurite outgrowth, which was attenuated by insulin-like growth factor 1 treatment.
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We demonstrate that brain ABCA1 deficiency increases BBB leakage, WM/axonal damage, and functional deficits after stroke. Concomitant reduction of insulin-like growth factor 1 and upregulation of matrix metalloproteinase-9 may contribute to brain ABCA1 deficiency-induced BBB and WM/axonal damage in the ischemic brain. Final Decision: yes