Microvascular research
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Microvascular research · Sep 2016
Comparative StudySanguinate's effect on pial arterioles in healthy rats and cerebral oxygen tension after controlled cortical impact.
Sanguinate, a polyethylene glycol-conjugated carboxyhemoglobin, was investigated for cerebral vasoactivity in healthy male Sprague-Dawley rats (Study 1) and for its ability to increase brain tissue oxygen pressure (PbtO2) after controlled cortical impact (CCI) - traumatic brain injury (TBI) (Study 2). In both studies ketamine-acepromazine anesthetized rats were ventilated with 40% O2. In Study 1, a cranial window was used to measure the diameters of medium - (50-100μm) and small-sized (<50μm) pial arterioles before and after four serial infusions of Sanguinate (8mL/kg/h, cumulative 16mL/kg IV), volume-matched Hextend, or normal saline. ⋯ Results showed: 1) in healthy rats, percentage changes in pial arteriole diameter were the same among the groups, 2) in TBI rats, PbtO2 decreased from 36.5±3.9mmHg to 19.8±3.0mmHg at T15 in both groups after TBI and did not recover in either group for the rest of the study, and 3) MAP increased 16±4mmHg and 36±5mmHg after Sanguinate in healthy and TBI rats, respectively, while MAP was unchanged in control groups. In conclusion, Sanguinate did not cause vasoconstriction in the cerebral pial arterioles of healthy rats but it also did not acutely increase PbtO2 when administered after TBI. Sanguinate was associated with an increase in MAP in both studies.
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Microvascular research · Jul 2016
Vasopressin V1A receptors mediate the stabilization of intestinal mucosal oxygenation during hypercapnia in septic rats.
Microvascular oxygen saturation (μHBO2) plays an essential role in the development and outcome of sepsis. Hypercapnia (HC) improves the microvascular oxygenation of the mucosa in both healthy and septic animals. Vasopressin V1A receptor blockade prevents this positive effect under otherwise physiological conditions. The aim of this study was to investigate the effects and mechanisms of the vasopressin system during hypercapnia under septic conditions. ⋯ Vasopressin V1A receptors mediate the beneficial effects of hypercapnia on microcirculatory oxygenation during sepsis. The effects of vasopressin on μHBO2 might be related to decreased oxygen consumption during hypercapnia.
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Microvascular research · Jul 2016
Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R.
Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear. ⋯ The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB.
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Microvascular research · May 2016
Overexpression of hypoxia-inducible factor-1 alpha improves vasculogenesis-related functions of endothelial progenitor cells.
Postnatal vasculogenesis is mediated by mobilization of endothelial progenitor cells (EPCs) from bone marrow and homing to ischemic tissues. This feature emphasizes this cell type for cell-based therapies aiming at the improvement of neovascularization in tissue engineering applications and regenerative medicine. In animal models, it was demonstrated that implantation of EPCs from cord blood (cbEPCs) led to the formation of a complex functional neovasculature, whereas EPCs isolated from adult peripheral blood (pbEPCs) showed a limited vasculogenic potential, which may be attributed to age-related dysfunction. ⋯ Similarly, the colony-formation capacity was much higher in cbEPCs in comparison to pbEPCs and was further increased by Hif-1α overexpression, whereas Hif-1α transduction exerted no significant influence on colony formation of pbEPCs. In summary, our experiments illustrated multifarious effects of Hif-1α overexpression on stem cell and vasculogenic parameters. Therefore, Hif-1α overexpression may represent a therapeutic option to improve cellular functions of adult as well as postnatal EPCs.
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Microvascular research · May 2016
The waveform index of the ophthalmic artery predicts impaired coronary flow reserve.
Coronary flow reserve (CFR) can decrease with impairment in coronary microcirculation, even in the absence of epicardial conduit obstruction. Recently, the ophthalmic artery (OA), which is the first major branch of the internal carotid artery and is representative of microarterioles, has been identified using color Doppler sonography. However, the features of ultrasound waveform indices suggestive of impaired OA microcirculation and the relationships between these indices and CFR have not been elucidated. The present study aimed to assess the features of ultrasound waveform indices suggestive of impaired OA microcirculation and the relationships between these indices and CFR. ⋯ An increase in the Sm/Dm ratio, which reflects a characteristic waveform, indicates impaired OA microcirculation. The ratio is negatively correlated with CFR, and therefore, it may be applied for the noninvasive evaluation of coronary physiology. Furthermore, hemoglobin A1c may be a common mediator for the OA and coronary microcirculation.