Cerebral microhemorrhages (CMHs) are considered as asymptomatic lesions, but might impair cognition in non-demented elderly individuals. The aging process includes poor vascular health, enhanced at midlife by metabolic disturbances upon high-fat diet (HFD). The onset of CMHs could thus have more serious consequences in midlife subjects with metabolic disturbances. This hypothesis was tested through the induction of multiple CMHs, using cyclodextrin nanoparticles injection, in mice at midlife (14 month old) or at a younger stage (5 month old) after 12 months or 3 months of normal diet or HFD (40% of animal fat) respectively. When induced at 14 months of age, CMHs were not larger but were more numerous (+25%) in mice on HFD compared with mice on normal diet. They slowed down the locomotor activity significantly but caused neither a change in the working memory nor a difference in the visual recognition memory decline. When induced at 5 months of age, CMHs provoked slighter locomotor and cognitive symptoms, regardless the diet. No spontaneous progression of CMHs toward larger hemorrhages was observed after onset when HFD was prolonged up to midlife. Consistently, no precipitated cognitive decline was observed. Middle-age plus time of metabolic disturbances represent enhanced risk factors for CMH outcome.

中文翻译：

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年龄和饮食改变小鼠大脑中的急性微出血结果

脑微出血 (CMH) 被认为是无症状病变，但可能会损害非痴呆老年人的认知能力。衰老过程包括血管健康状况不佳，在中年时因高脂肪饮食 (HFD) 的代谢紊乱而加剧。因此，CMH 的发作可能会对患有代谢紊乱的中年受试者产生更严重的后果。该假设通过使用环糊精纳米颗粒注射在中年（14 个月大）或年轻阶段（5 个月大）的小鼠中，在正常饮食或 HFD 12 个月或 3 个月后（40%动物脂肪）分别。当在 14 个月大时诱导时，与正常饮食的小鼠相比，使用 HFD 的小鼠中的 CMH 并不更大，但数量更多（+25%）。它们显着减慢了运动活动，但既没有引起工作记忆的变化，也没有引起视觉识别记忆衰退的差异。在 5 个月大时诱导时，无论饮食如何，CMH 都会引起较轻微的运动和认知症状。当 HFD 延长到中年时，没有观察到 CMHs 向更大出血的自发进展。一致地，没有观察到明显的认知衰退。中年加上代谢紊乱的时间代表了 CMH 结果的危险因素。一致地，没有观察到明显的认知衰退。中年加上代谢紊乱的时间代表了 CMH 结果的危险因素。一致地，没有观察到明显的认知衰退。中年加上代谢紊乱的时间代表了 CMH 结果的危险因素。