scholarly journals More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Baoqiang Li ◽  
Tatiana V Esipova ◽  
Ikbal Sencan ◽  
Kıvılcım Kılıç ◽  
Buyin Fu ◽  
...  
Keyword(s):  
Oxygen Delivery ◽  
Barrel Cortex ◽  
Capillary Flow ◽  
Oxygen Demand ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Homogeneous Distribution ◽  
Metabolic Demand ◽  
Cortical Layers ◽  
Network Adaptation

Our understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of resting-state microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that more homogeneous distribution of the physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to local brain metabolism. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of the diseases that affect cerebral microcirculation.

scholarly journals Homogenization of capillary flow and oxygenation in deeper cortical layers correlates with increased oxygen extraction

2018 ◽  
Author(s):  
Baoqiang Li ◽  
Tatiana V. Esipova ◽  
Ikbal Sencan ◽  
Kivilcim Kilic ◽  
Buyin Fu ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Delivery ◽  
Capillary Flow ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cortical Layers ◽  
Microvascular Network ◽  
Local Brain

ABSTRACTOur understanding of how capillary blood flow and oxygen distribute across cortical layers to meet the local metabolic demand is incomplete. We addressed this question by using two-photon imaging of microvascular oxygen partial pressure (PO2) and flow in the whisker barrel cortex in awake mice at rest. Our measurements in layers I-V show that the capillary red-blood-cell flux and oxygenation heterogeneity, and the intracapillary resistance to oxygen delivery, all decrease with depth, reaching a minimum around layer IV, while the depth-dependent oxygen extraction fraction is increased in layer IV, where oxygen demand is presumably the highest. Our findings suggest that homogenization of physiological observables relevant to oxygen transport to tissue is an important part of the microvascular network adaptation to a local brain metabolism increase. These results will inform the biophysical models of layer-specific cerebral oxygen delivery and consumption and improve our understanding of diseases that affect the cerebral microcirculation.IMPACT STATEMENTHomogenization of cortical capillary blood flow and oxygenation underpins an important mechanism, by which the microvascular network adapts to an increase in the local brain oxidative metabolism.

scholarly journals Tomographic Mapping of Brain Intracellular pH and Extracellular Water Space in Stroke Patients

1985 ◽  
Vol 5 (3) ◽  
pp. 358-368 ◽  
Author(s):  
A. Syrota ◽  
Y. Samson ◽  
C. Boullais ◽  
P. Wajnberg ◽  
C. Loc'h ◽  
...  
Keyword(s):  
Intracellular Ph ◽  
Aerobic Glycolysis ◽  
Oxygen Metabolism ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Extracellular Water ◽  
Metabolic Demand ◽  
Phagocytic Cells ◽  
Infarcted Area ◽  
Positron Emission

Functional images of regional intracellular pH (pHi) and of fractional volume of extracellular water (FVECW) were obtained in 10 patients with recent hemispheric infarction (between 10 and 19 days after onset of symptoms) using positron emission tomography (PET). The volume of extracellular water relative to that of total water was evaluated in each pixel of the PET scan 7–8 h after injection of 76Br. The pHi image was calculated from the data obtained after injection of [11C]5,5-dimethyl-2,4-oxazolidinedione and from the FVECW image. Regional CBF, oxygen extraction, and oxygen metabolism were also measured in the same patients. In normal hemisphere, mean ± SD values for FVECW and pHi were 0.12 ± 0.01 and 6.86 ± 0.11, respectively. FVECW was increased in the infarcted area in most patients. pHi was increased in the infarct in seven patients and unchanged in three. The increase in pHi was not correlated with changes in FVECW, CBF, or CMRO2, but there was a significant correlation with the decrease in oxygen extraction fraction in the same region. Thus, the decreased H+ content in the infarcted area was correlated with the occurrence of perfusion in excess of metabolic demand. An alkaline shift in pHi enhances the glycolysis rate and could explain why the glucose metabolism is less affected than the oxygen metabolism in recent cerebral infarction. The pHi measured in the infarct could represent mainly the pHi of phagocytic cells that use aerobic glycolysis to synthesize hydrogen peroxide.

Reduction in oxygen demand, normalization of oxygen delivery and oxygen extraction

1996 ◽  
Vol 5 (2) ◽  
pp. 302-312 ◽  
Author(s):  
C.C. Berton ◽  
B. Schnitzler ◽  
B. Thill
Keyword(s):  
Oxygen Delivery ◽  
Oxygen Demand ◽  
Oxygen Extraction

scholarly journals Author response: More homogeneous capillary flow and oxygenation in deeper cortical layers correlate with increased oxygen extraction

2018 ◽  
Author(s):  
Baoqiang Li ◽  
Tatiana V Esipova ◽  
Ikbal Sencan ◽  
Kıvılcım Kılıç ◽  
Buyin Fu ◽  
...  
Keyword(s):  
Capillary Flow ◽  
Author Response ◽  
Oxygen Extraction ◽  
Cortical Layers

scholarly journals Oxygen Extraction Fraction at Maximally Vasodilated Tissue in the Ischemic Brain Estimated from the Regional CO2 Responsiveness Measured by Positron Emission Tomography

1988 ◽  
Vol 8 (2) ◽  
pp. 227-235 ◽  
Author(s):  
Iwao Kanno ◽  
Kazuo Uemura ◽  
Schuichi Higano ◽  
Matsutaro Murakami ◽  
Hidehiro Iida ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Resting State ◽  
Emission Tomography ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Cross Point ◽  
Steady State Method ◽  
Extraction Fraction ◽  
Positron Emission ◽  
Vascular Responsiveness

The oxygen extraction fraction (OEF) at maximally vasodilated tissue in patients with chronic cerebrovascular disease was evaluated using positron emission tomography. The vascular responsiveness to changes in PaCO2 was measured by the H215O autoradiographic method. It was correlated with the resting-state OEF, as estimated using the 15O steady-state method. The subjects comprised 15 patients with unilateral or bilateral occlusion and stenosis of the internal carotid artery or middle cerebral artery or moyamoya disease. In hypercapnia, the scattergram between the OEF and the vascular responsiveness to changes in PaCO2 revealed a significant negative correlation in 11 of 19 studies on these patients, and the OEF at the zero cross point of the regression line with a vascular responsiveness of 0 was 0.53 ± 0.08 (n = 11). This OEF in the resting state corresponds to exhaustion of the capacity for vasodilation. The vasodilatory capacity is discussed in relation to the lower limit of autoregulation.

Reversal of Focal Misery Perfusion after Intracranial Angioplasty: Case Report

Neurosurgery ◽  
2001 ◽  
Vol 48 (2) ◽  
pp. 436-440 ◽  
Author(s):  
Colin P. Derdeyn ◽  
DeWitte T. Cross ◽  
Christopher J. Moran ◽  
Ralph G. Dacey
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Intracranial Stenosis ◽  
Oxygen Extraction Fraction ◽  
Oxygen Extraction ◽  
Positron Emission ◽  
Misery Perfusion ◽  
Before And After ◽  
Hemodynamic Measurements

Abstract OBJECTIVE AND IMPORTANCE The presence of reduced blood flow and increased oxygen extraction fraction (OEF) (misery perfusion) in the hemisphere distal to an occluded carotid artery is a proven risk factor for subsequent stroke. Whether angioplasty of intracranial stenosis is sufficient to reverse this condition has not been documented. CLINICAL PRESENTATION A 67-year-old man exhibited progressive right hemispheric ischemic symptoms despite maximal antiplatelet and antithrombotic therapy. Angiography demonstrated focal 80% stenosis of the supraclinoid segment of the ipsilateral internal carotid artery. TECHNIQUE 15O positron emission tomographic measurements of cerebral blood flow and OEF were made before and after transfemoral percutaneous angioplasty. OEF values measured before angioplasty were elevated in the middle cerebral artery distal to the stenosis. Angioplasty reduced the degree of luminal stenosis to 40% (linear diameter). OEF values measured 36 hours after angioplasty were normal. CONCLUSION Angioplasty of intracranial stenosis can restore normal cerebral blood flow and oxygen extraction, despite mild residual stenosis after the procedure. Hemodynamic measurements may be useful for the identification of patients with the greatest potential to benefit from angioplasty.

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