Aspirin treatment does not increase microhemorrhage size in young or aged mice

A Mild Dose of Aspirin Promotes Hippocampal Neurogenesis and Working Memory in Experimental Ageing Mice

Aspirin has been reported to prevent memory decline in the elderly population. Adult neurogenesis in the hippocampus has been recognized as an underlying basis of learning and memory. This study investigated the effect of aspirin on spatial memory in correlation with the regulation of hippocampal neurogenesis and microglia in the brains of ageing experimental mice. Results from the novel object recognition (NOR) test, Morris water maze (MWM), and cued radial arm maze (cued RAM) revealed that aspirin treatment enhances working memory in experimental mice. Further, the co-immunohistochemical assessments on the brain sections indicated an increased number of doublecortin (DCX)-positive immature neurons and bromodeoxyuridine (BrdU)/neuronal nuclei (NeuN) double-positive newly generated neurons in the hippocampi of mice in the aspirin-treated group compared to the control group. Moreover, a reduced number of ionized calcium-binding adaptor molecule (Iba)-1-positive microglial cells was evident in the hippocampus of aspirin-treated animals. Recently, enhanced activity of acetylcholinesterase (AChE) in circulation has been identified as an indicative biomarker of dementia. The biochemical assessment in the blood of aspirin-treated mice showed decreased activity of AChE in comparison with that of the control group. Results from this study revealed that aspirin facilitates hippocampal neurogenesis which might be linked to enhanced working memory.

Aspirin does not affect hematoma growth in severe spontaneous intracranial hematoma

Hematoma growth (HG) affects the prognosis of patients with spontaneous intracranial hematoma (ICH), but there is still a lack of evidence about the effects of aspirin (acetylsalicylic acid, ASA) on HG in patients with severe ICH. This study retrospectively analyzed patients with severe ICH who met the inclusion and exclusion criteria in Beijing Tiantan Hospital, Capital Medical University, between January 1, 2015, and July 31, 2019. Severe ICH patients were divided into ASA group and nASA groups according to ASA usage, and the incidence of HG between the groups was compared. Univariate analysis was performed by the Mann-Whitney U test, chi-square test, or Fisher exact test. Multivariate logistic regression analysis was used to analyze the impact of ASA on HG and to screen for risk factors of HG. In total, 221 patients with severe ICH were consecutively enrolled in this study. There were 72 (32.6%) patients in the ASA group and 149 patients in the nASA group. Although the incidence of HG in the nASA group was higher than that in the ASA group (34.9% VS 22.2%, p = 0.056), ASA did not significantly affect the occurrence of HG (p = 0.285) after adjusting for initial hematoma volume, high blood pressure at admission, coronary heart disease, and GCS at admission. In addition, we found that high blood pressure at admission was a risk factor for HG. Prior ASA does not increase the incidence of HG in severe ICH patients, and high blood pressure at admission is a risk factor for HG.

In vivo characterization of spontaneous microhemorrhage formation in mice with cerebral amyloid angiopathy

The pathophysiology of microhemorrhages in the context of cerebral amyloid angiopathy (CAA) remains poorly understood. Here we used in vivo two-photon microscopy in aged APP/PS1 mice with mild-to-moderate CAA to assess the formation of microhemorrhages and their spatial relationship with vascular Aβ depositions in the surrounding microvascular network. Mice with chronic cranial windows were intravenously injected with fluorescent dextran to visualize the vessels and a fluorescently labeled anti-fibrin antibody to visualize microhemorrhages. Focal vessel irradiations resulted in extravascular fibrin-positive clots at individual rupture sites that remained visible for weeks. Spontaneous extravascular fibrin-positive clots were more often observed in 19-month-old transgenic APP/PS1 mice compared to their wild-type littermate controls (p = 0.039), after heparin administration. In the transgenic mice, these spontaneous leakage sites frequently occurred at arteriolar segments without CAA at bifurcations or vessel bends. These findings suggest that the presence of vascular Aβ per se does not directly predispose vessels to leak, but that complex flow dynamics within CAA-affected vascular networks likely play a role. Our in vivo approach for the detection of individual spontaneous leakage sites may be used in longitudinal studies aimed to assess structural and functional alterations at the single-vessel level leading up to microhemorrhage formation.