Cerebral Microbleeds Associate with Brain Endothelial Cell Activation-Dysfunction and Blood-Brain Barrier Dysfunction-Disruption with an Increased Risk of Hemorrhagic and Ischemic Stroke That Is Capable of Exacerbating Neurodegeneration

Abstract Cerebral microbleed(s) (CMBs) are increasingly being viewed not only as a marker for cerebral small vessel disease (SVD) but also as having an increased risk for the development of stroke (hemorrhagic/ischemic) and aging-related dementia. Recently, brain endothelial cell activation and dysfunction and blood-brain barrier dysfunction and/or disruption have been shown to be associated with SVD, enlarged perivascular spaces, and the development and evolution of CMBs. CMBs are a known disorder of cerebral microvessels that are visualized as 3-5mm, smooth, round or oval, and hypointense (black) lesions seen only on T2*-weighted gradient recall echo or susceptibility-weighted sequences on MRI images. CMBs (a global problem) are known to occur with high prevalence in community-dwelling older individuals. Since our current global population is the oldest recorded in history and only expected to continue to grow, we can only expect the health care burdens associated with CMBs to also grow. CMBs should raise a red flag regarding the increased risk of large symptomatic neurologic intracerebral hemorrhages. Importantly, CMBs are also currently regarded as markers of diffuse vascular and neurodegenerative brain damage. Thus, it is essential that we try to learn as much as we can about their development, evolution, and their relation to impaired cognition, dementia, and neurodegeneration.