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Objective: Macrophages have been shown to play important roles in various pathophysiological processes of the central nervous system via neuroinflammation, leading to an increased interest in macrophage biology. Circulating blood monocytes are among the first cells to infiltrate the brain after ischemic stroke; however, the role of innate immune cells such as monocytes and macrophages remains to be elucidated. Here, we investigated the association between blood monocytes and infarct size following ischemic stroke., Methods: We induced stroke using a focal ischemia mouse model through middle cerebral artery suture occlusion. To deplete circulating blood monocytes, clodronate was injected intraperitoneally 24 h before the surgery. Animals were sacrificed at specified time points, and the infarct size and mRNA expression were then measured., Results: The clodronate-injected mice showed significantly smaller infarct size than the control mice. Immunohistochemical staining revealed that monocyte depletion significantly blocked the infiltration of macrophages and microglia. The mRNA expression levels of macrophage and microglia markers were higher in the left infarcted brain than in the right non-infarcted brain., Conclusions: In summary, monocyte depletion reduced the infarct size and mitigated neurological deficits in mice following ischemic stroke, likely by blocking the infiltration of inflammatory cells such as macrophages and microglia.

Abstract: Measurement of cortisol in hair is a reliable method for determining long-term cortisol exposure reflecting chronic stress. Research using hair cortisol concentration has been limited to mainly cardiometabolic diseases. The association between hair cortisol concentration and aneurysmal rupture has not yet been studied. We aimed to investigate the relationship between the degree of chronic stress as measured by hair cortisol concentration and aneurysmal rupture.Sixty-eight patients diagnosed with intracranial aneurysms were included in this study (ruptured group, 30; unruptured group, 38). Hair cortisol was measured in 3-cm hair segments, reflecting roughly 3 months of hair growth. For a risk factor analysis, patient-specific factors and aneurysm-specific factors as well as hair cortisol concentration were investigated.Hair cortisol concentrations were significantly higher in the ruptured group than in the unruptured group (55.8 ± 22.0 ng/dL vs. 19.1 ± 6.4 ng/dL; P < .001). High hair cortisol concentration was found to be an independent risk factor for aneurysmal rupture (odds ratio [OR]: 2.245, 95% confidence interval [CI]: 1.825-2.753; P = .013). Additionally, a history of cerebrovascular disease was significantly associated with an increased risk of aneurysmal rupture (OR: 1.577, 95% CI: 1.099-2.262; P = .040).Based on our results, we suggest that chronic stress as measured by hair cortisol concentration could be an independent risk factor for intracranial aneurysmal rupture., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Objective: Ischemic postconditioning (IPostC), consisted of transient brain ischemia/reperfusion cycles, is considered to have neuroprotective effect. However, there is no best single protocol of IPostC, because varied factors like species tested and characteristics of the tissue may affect the efficacy of IPostC. Thus, we investgated whether different protocols of IPostC affect neuroprotective effects in experimental animal models., Materials and Methods: Through occlusion of middle cerebral artery (MCA) with intraluminal suture, stroke was induced in a transient focal ischemia model in mice. We conducted IPostC via brief and repeated MCA occlusion, 2 minutes after reperfusion, followed by different ischemia and reperfusion protocols. After procedure, functional neurological score and histological examination were evaluated., Results: IPostC with different protocols resulted in diverse effects. Among them, a protocol that consists of 3 cycle of IPostC significantly reduced the infarction size 3 days after stroke., Conclusion: IPostC was confirmed to reduce infarction size. The effects of IPostC are definitely affected by differences in the protocol used, including the number of cycles, the duration of individual ischemia/reperfusion episode and the entire duration of the IPostC stimuli., Competing Interests: Disclosure: The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.