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Hyperglycemia-induced cerebral hematoma expansion is mediated by plasma kallikrein.

ABSTRACT: Hyperglycemia is associated with greater hematoma expansion and poor clinical outcomes after intracerebral hemorrhage. We show that cerebral hematoma expansion triggered by intracerebral infusion of autologous blood is greater in diabetic rats and mice compared to nondiabetic controls and that this augmented expansion is ameliorated by plasma kallikrein (PK) inhibition or deficiency. Intracerebral injection of purified PK augmented hematoma expansion in both diabetic and acutely hyperglycemic rats, whereas injection of bradykinin, plasmin or tissue plasminogen activator did not elicit such a response. This response, which occurs rapidly, was prevented by co-injection of the glycoprotein VI agonist convulxin and was mimicked by glycoprotein VI inhibition or deficiency, implicating an effect of PK on inhibiting platelet aggregation. We show that PK inhibits collagen-induced platelet aggregation by binding collagen, a response enhanced by elevated glucose concentrations. The effect of hyperglycemia on hematoma expansion and PK-mediated inhibition of platelet aggregation could be mimicked by infusing mannitol. These findings suggest that hyperglycemia augments cerebral hematoma expansion by PK-mediated osmotic-sensitive inhibition of hemostasis.

SUBMITTER: Liu J

PROVIDER: S-EPMC3038677 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature

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Hyperglycemia-induced cerebral hematoma expansion is mediated by plasma kallikrein.

Liu Jia J Gao Ben-Bo BB Clermont Allen C AC Blair Price P Chilcote Tamie J TJ Sinha Sukanto S Flaumenhaft Robert R Feener Edward P EP

Nature medicine 20110123 2

Hyperglycemia is associated with greater hematoma expansion and poor clinical outcomes after intracerebral hemorrhage. We show that cerebral hematoma expansion triggered by intracerebral infusion of autologous blood is greater in diabetic rats and mice compared to nondiabetic controls and that this augmented expansion is ameliorated by plasma kallikrein (PK) inhibition or deficiency. Intracerebral injection of purified PK augmented hematoma expansion in both diabetic and acutely hyperglycemic ra ...[more]

PMID: 21258336

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Project description:Background and objectiveThe aim of this study was to evaluate the impact of radiographic cerebral small vessel disease (CSVD) on the severity of acute intracerebral hemorrhage (ICH) as measured by: ICH volume, hematoma expansion, and extension of intraventricular hemorrhage (IVH).MethodsCSVD was determined on baseline computed tomography (CT) scans of patients from the Ethnic and Racial Variations of Intracerebral Hemorrhage study through the extent of leukoaraiosis and cerebral atrophy using visual rating scales. The associations of leukoaraiosis and atrophy with ICH volume, hematoma expansion, IVH presence, and severity of IVH were tested using multivariable regression models. Secondary analyses were stratified by hemorrhage location. Bonferroni correction was applied to correct for multiple testing.ResultsA total of 2579 patients (mean age 61.7 years, 59% male) met inclusion criteria. Median ICH volume was 10.5 (Interquartile range [IQR] 4.0-25.3) mL. IVH was detected in 971 patients (38%). Neither leukoaraiosis nor atrophy was associated with hematoma expansion. Increasing grades of leukoaraiosis were associated with increased risk of IVH in a dose-dependent manner, while cerebral atrophy was inversely associated with IVH (both P for trend < 0.001). Increasing grades of global atrophy were dose-dependently associated with lower ICH volumes (ß (95% Confidence Interval [CI]) - 0.30[- 0.46, - 0.14], - 0.33[- 0.49, - 0.17], - 0.40[- 0.60, - 0.20], and - 0.54[- 0.76, - 0.32], for grades 1, 2, 3 and 4 compared to 0; all P < 0.001). The associations of leukoaraiosis with ICH volume were consistent with those of atrophy, albeit not meeting statistical significance.ConclusionsLeukoaraiosis and cerebral atrophy appear to have opposing associations with ICH severity. Cerebral atrophy correlates with smaller ICH volume and decreased risk and severity of IVH, while leukoaraiosis is associated with increased risk of IVH. Whether these observations reflect overlapping or divergent underlying mechanisms requires further study.

Project description:Diabetic cardiovascular complications are characterised by oxidative stress-induced endothelial dysfunction. Uncoupling protein 2 (UCP2) is a regulator of mitochondrial reactive oxygen species (ROS) generation and can antagonise oxidative stress, but approaches that enhance the activity of UCP2 to inhibit ROS are scarce. Our previous studies show that activation of transient receptor potential vanilloid 1 (TRPV1) by capsaicin can prevent cardiometabolic disorders. In this study, we conducted experiments in vitro and in vivo to investigate the effect of capsaicin treatment on endothelial UCP2 and oxidative stress. We hypothesised that TRPV1 activation by capsaicin attenuates hyperglycemia-induced endothelial dysfunction through a UCP2-mediated antioxidant effect.TRPV1(-/-), UCP2(-/-) and db/db mice, as well as matched wild type (WT) control mice, were included in this study. Some mice were subjected to dietary capsaicin for 14 weeks. Arteries isolated from mice and endothelial cells were cultured. Endothelial function was examined, and immunohistological and molecular analyses were performed.Under high-glucose conditions, TRPV1 expression and protein kinase A (PKA) phosphorylation were found to be decreased in the cultured endothelial cells, and the effects of high-glucose on these molecules were reversed by the administration of capsaicin. Furthermore, high-glucose exposure increased ROS production and reduced nitric oxide (NO) levels both in endothelial cells and in arteries that were evaluated respectively by dihydroethidium (DHE) and DAF-2 DA fluorescence. Capsaicin administration decreased the production of ROS, restored high-glucose-induced endothelial dysfunction through the activation of TRPV1 and acted in a UCP2-dependent manner in vivo. Administration of dietary capsaicin for 14 weeks increased the levels of PKA phosphorylation and UCP2 expression, ameliorated the vascular oxidative stress and increased NO levels observed in diabetic mice. Prolonged dietary administration of capsaicin promoted endothelium-dependent relaxation in diabetic mice. However, the beneficial effect of capsaicin on vasorelaxation was absent in the aortas of UCP2(-/-) mice exposed to high-glucose levels.TRPV1 activation by capsaicin might protect against hyperglycemia-induced endothelial dysfunction through a mechanism involving the PKA/UCP2 pathway.

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Hyperglycemia-induced cerebral hematoma expansion is mediated by plasma kallikrein.

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Hyperglycemia-induced cerebral hematoma expansion is mediated by plasma kallikrein.

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