Oxygen delivery at high blood viscosity and decreased arterial oxygen content to brains of conscious rats

Rebel, Annette; Lenz, Christian; Krieter, H.; Waschke, Klaus F.; Ackern, K. van; Kuschinsky, Wolfgang

doi:10.1152/ajpheart.2001.280.6.h2591

Cited by 36 publications

(20 citation statements)

References 25 publications

(36 reference statements)

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“…vasodilation or vasoconstriction capability) . When vascular reserve is depleted, blood flow to some organs may be substantially reduced owing to increased blood viscosity (Most et al 1986;Baskurt et al 1991;Dalinghaus et al 1994;Rebel et al 2001). Therefore, specific adaptations may also exist in the vasculature of these marsupials that may facilitate oxygen transfer despite their lower HVR.…”

Section: Discussionmentioning

confidence: 99%

Haemorheology of the eastern grey kangaroo and the Tasmanian devil

et al. 2011

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The blood of two Australian marsupials, the eastern grey kangaroo (Macropus giganteus) and the Tasmanian devil (Sarcophilus harrisii), has been reported to have greater oxygen-carrying capacity (i.e. haemoglobin content) when compared with that of placental mammals. We investigated whether alterations of blood rheological properties are associated with the increased oxygen-carrying capacity of these marsupials. Eastern grey kangaroos (n = 6) and Tasmanian devils (n = 4) were anaesthetised for blood sampling; human blood (n = 6) was also sampled for comparison. Laboratory measurements included blood and plasma viscosity, red blood cell (RBC) deformability, RBC aggregation and the intrinsic tendency of RBC to aggregate, RBC surface charge and haematological parameters. Scanning electron micrographs of RBC from each species provided morphological information. High-shear blood viscosity at native haematocrit was highest for the Tasmanian devil. When haematocrit was adjusted to 0.4 L L -1 , lower-shear blood viscosity was highest for the eastern grey kangaroo. RBC deformability was greatly reduced for the Tasmanian devil. Eastern grey kangaroo blood had the highest RBC aggregation, whereas Tasmanian devil RBC did not aggregate. The surface charge of RBC for marsupials was~15% lower than that of humans. The dependence of oxygen-delivery effectiveness on haemoglobin concentration (i.e. oxygen content) and blood viscosity was quantitated by calculating the haematocrit to blood viscosity ratio and was 15-25% lower for marsupials compared with humans. Our results suggest that environmental pressures since the marsupial-monotreme divergence have influenced the development of vastly different strategies to maintain a match between oxygen demand and delivery.

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Section: Discussionmentioning

confidence: 99%

Haemorheology of the eastern grey kangaroo and the Tasmanian devil

et al. 2011

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“…(51) This compensatory mechanism may be exhausted when pre-existing vasodilation impairs the ability of vessels to dilate further to changes in viscosity. (52) All of these responses of the cerebral vasculature have been determined at normal CPP. When CPP varies, a different set of cerebrovascular and brain metabolic responses occur.…”

Section: Cerebrovascular Controlmentioning

confidence: 99%

PET in Cerebrovascular Disease

Zazulia

2010

PET Clinics

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SYNOPSISInvestigation of the interplay between the cerebral circulation and brain cellular function is fundamental to understanding both the pathophysiology and treatment of stroke. Currently, PET is the only technique that provides accurate, quantitative in vivo regional measurements of both cerebral circulation and cellular metabolism in human subjects. We review normal human cerebral blood flow and metabolism and human PET studies of ischemic stroke, carotid artery disease, vascular dementia, intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage and discuss how these studies have added to our understanding of the pathophysiology of human cerebrovascular disease. Keywordspositron emission tomography; cerebrovascular disease; vascular dementia; cerebral blood flow; cerebral metabolism; cerebral hemodynamics INTRODUCTIONCerebrovascular disease results from a derangement of the normal relationship between the cerebral vasculature and the brain parenchyma. Thus, investigation of the interplay between the cerebral circulation and brain cellular function is fundamental to understanding both the pathophysiology and treatment of stroke. Currently, PET is the only technique that provides accurate, quantitative in vivo regional measurements of both cerebral circulation and cellular metabolism in human subjects. It is therefore well-suited for the study of human cerebrovascular disease, but its application to this end is not easy. An on-site cyclotron and radiochemistry facility is necessary due to the short half-lives of the commonly used radionuclides 15 O (2 minutes) and 11 C (20 minutes). Quantitative physiological measurements require complex postprocessing and multiple arterial blood samples, although for some specific applications simple count-based images can be used.(1;2) Patients with acute stroke may be medically unstable, requiring a nurse or physician in attendance. For these reasons, PET is still a research tool for cerebrovascular disease. It has provided us with valuable new knowledge and insight into both ischemic and hemorrhagic stroke regarding pathophysiology, therapy and Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public AccessAuthor Manuscript PET Clin. Author manuscript; available in PMC 2011 January 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript prognosis but has not entered the mainstream of clinical practice. In the future, the results of the Carotid Occlusion Surgery Study (www.cosstrial.org), an ongoing clinical trial in which PET is being used to determine eligibility, may demonstrate the clinical value ...

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“…Second, polyvinylpyrrolidone ($1.1 MDa) is used as a plasma expander and in studies of brain circulation [29]. It is inexpensive; however, it causes immune and inflammatory reactions related to the distribution of molecular weights in the compound, and it is no longer approved for human use in the United States.…”

Section: The Viscosity Of Plasma Expandersmentioning

confidence: 99%

Microcirculatory effects of intravenous fluids in critical illness: plasma expansion beyond crystalloids and colloids

Intaglietta

2009

Current Opinion in Anaesthesiology

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Preclinical studies show that polyethylene glycol-conjugated albumin at concentrations in the range of 2-4% extends the transfusion trigger, providing the more extended and complete microvascular and systemic recovery from hemorrhagic shock, extreme hemodilution and endotoxemia, postponing the need of reestablish intrinsic blood oxygen-carrying capacity to hemoglobin concentrations lower than those associated with accepted transfusion triggers.

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Oxygen delivery at high blood viscosity and decreased arterial oxygen content to brains of conscious rats

Cited by 36 publications

References 25 publications

Haemorheology of the eastern grey kangaroo and the Tasmanian devil

Haemorheology of the eastern grey kangaroo and the Tasmanian devil

PET in Cerebrovascular Disease

Microcirculatory effects of intravenous fluids in critical illness: plasma expansion beyond crystalloids and colloids

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