BackgroundMicroglia are the resident macrophage population of the central nervous system (CNS) and play essential roles, particularly in inflammation-mediated pathological conditions such as ischemic stroke. Increasing evidence shows that the population of vascular cells located around the blood vessels, rather than circulating cells, harbor stem cells and that these resident vascular stem cells (VSCs) are the likely source of some microglia. However, the precise traits and origins of these cells under pathological CNS conditions remain unclear.MethodsIn this study, we used a mouse model of cerebral infarction to investigate whether reactive pericytes (PCs) acquire microglia-producing VSC activity following ischemia.ResultsWe demonstrated the localization of ionized calcium-binding adaptor molecule 1 (Iba1)-expressing microglia to perivascular regions within ischemic areas. These cells expressed platelet-derived growth factor receptor-β (PDGFRβ), a hallmark of vascular PCs. PDGFRβ+ PCs isolated from ischemic, but not non-ischemic, areas expressed stem/undifferentiated cell markers and subsequently differentiated into various cell types, including microglia-like cells with phagocytic capacity.ConclusionsThe study results suggest that vascular PCs acquire multipotent VSC activity under pathological conditions and may thus be a novel source of microglia.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-016-0523-9) contains supplementary material, which is available to authorized users.

Chick embryos exposed to VPA during the last week of embryogenesis had impaired social behaviors in spite of normal mortar and imprinting ability. The present method will be a useful animal model for assessing the effects of environment during embryogenesis on social behaviors in later life.

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Six Japanese children with rapidly progressive Henoch-Schönlein purpura nephritis (HSPN) received multiple drug therapy combined with plasmapheresis (PP). After five courses of PP, multiple drug therapy, including methylprednisolone and urokinase pulse therapy, oral prednisolone, cyclophophamide, dipyridamole, and warfarin was given. At presentation, urine protein excretion and histological indices of the mean activity and chronicity were 245+/-101 mg/m(2) per hour, 6.6+/-1.2, and 1.5+/-1.3, respectively. After 6 months of therapy, urinary protein excretion had decreased significantly ( P<0.001). The activity index decreased significantly at the second renal biopsy performed at a mean interval of 4.3 months after the first (2.8+/-1.4, P<0.05), while the chronicity index did not change. At the most recent observation, all showed clinical improvement. Two patients had normal urine, three had proteinuria of <20 mg/m(2) per hour, one had proteinuria of >20 mg/m(2) per hour, and none had renal insufficiency. Although this case series is without controls, our treatment protocol may be of benefit to children with rapidly progressive HSPN.