Inflammatory changes have been postulated to contribute to secondary brain injury after aneurysmal subarachnoid hemorrhage (SAH). In human specimens after SAH as well as in experimental SAH using mice, we show an intracerebral accumulation of inflammatory cells between days 4 and 28 after the bleeding. Using bone marrow chimeric mice allowing tracing of all peripherally derived immune cells, we confirm a truly CNS-intrinsic, microglial origin of these immune cells, exhibiting an inflammatory state, and rule out invasion of myeloid cells from the periphery into the brain. Furthermore, we detect secondary neuro-axonal injury throughout the time course of SAH. Since neuronal cell death and microglia accumulation follow a similar time course, we addressed whether the occurrence of activated microglia and neuro-axonal injury upon SAH are causally linked by depleting microglia in vivo. Given that the amount of neuronal cell death was significantly reduced after microglia depletion, we conclude that microglia accumulation inflicts secondary brain injury after SAH.
Activation of innate immunity contributes to secondary brain injury after experimental subarachnoid hemorrhage (eSAH). Microglia accumulation and activation within the brain has recently been shown to induce neuronal cell death after eSAH. In isolated mouse brain capillaries after eSAH, we show a significantly increased gene expression for intercellular adhesion molecule-1 (ICAM-1) and P-selectin. Hence, we hypothesized that extracerebral intravascular inflammatory processes might initiate the previously reported microglia accumulation within the brain tissue. We therefore induced eSAH in knockout mice for ICAM-1 (ICAM-1) and P-selectin glycoprotein ligand-1 (PSGL-1) to find a significant decrease in neutrophil-endothelial interaction within the first 7 days after the bleeding in a chronic cranial window model. This inhibition of neutrophil recruitment to the endothelium results in significantly ameliorated microglia accumulation and neuronal cell death in knockout animals in comparison to controls. Our results suggest an outside-in activation of the CNS innate immune system at the vessel/brain interface following eSAH. Microglia cells, as part of the brain's innate immune system, are triggered by an inflammatory reaction in the microvasculature after eSAH, thus contributing to neuronal cell death. This finding offers a whole range of new research targets, as well as possible therapy options for patients suffering from eSAH.
An endonasal technique is indicated for patients presenting with narrowness of the oral cavity, such as in the case reported, where the narrowness due to pediatric age and the macroglossia characteristic of Down syndrome hamper the transoral approach.
Although several series of pineal region tumors are available, the issue of pineal gliomas has been scarcely faced in the literature. Gliomas are usually included in largest series of pineal neoplasms. Therefore, whether pineal gliomas share the biological behavior of either hemispheric gliomas or other midline lesions is not yet defined. The aim of this retrospective study is to analyze long-term morbidity and mortality of these lesions. In English published literature gliomas account for about 14-22 % of all pineal region tumors. Most of these tumors are pilocytic astrocytomas, while glioblastoma multiforme is rare. We retrospectively analyzed all pineal region tumors operated on in our department in the last 28 years, and identified eight pineal astrocytomas, accounting for 14.03 % of all pineal tumors. The series includes four pilocytic astrocytomas, two grade II diffuse astrocytomas, and two anaplastic astrocytomas. A comprehensive review of the available literature data shows that the mean survival time of WHO grade II gliomas is shorter when tumor grows in the pineal region than for hemispheric locations, although the limited amount of available data prevents a rigorous statistical analysis. This difference might be due to the peculiar infiltrating behavior of pineal tumors, which often can't be satisfactorily resected from vital structures.
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