Cerebral hemodynamics in preterm infants during positional intervention measured with diffuse correlation spectroscopy and transcranial Doppler ultrasound

Buckley, Erin M.; Cook, Noah; Durdurán, Turgut; Kim, Meeri N.; Zhou, Chao; Choe, Regine; Yu, Guoqiang; Schultz, Susan M.; Sehgal, Chandra M.; Licht, Daniel J.; Arger, Peter H.; Putt, Mary; Hurt, Hallam; Yodh, Arjun G.

doi:10.1364/oe.17.012571

Cited by 157 publications

(163 citation statements)

References 52 publications

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“…27 DCS has been validated directly in many murine and human tissues against laser Doppler, Doppler ultrasound, Xenoncomputed tomography, microsphere velocimetry, power spectral ultrasound, and arterial spin-labeled MRI. 17,[28][29][30][31][32][33][34][35][36] Moreover, DCS for RH in our mice provided similar blood flow data 27 to that reported for MNRI-C57BL/6 mice using arterial spin-labeled MRI. 29 The higher time resolution of DCS, however, allowed us to relate the kinetics of neutrophil shear responses to RH.…”

supporting

confidence: 84%

Shear-Sensitive Regulation of Neutrophil Flow Behavior and Its Potential Impact on Microvascular Blood Flow Dysregulation in Hypercholesterolemia

Zhang

Cheng

Rowe

et al. 2014

ATVB

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Objective-Shear stress-induced pseudopod retraction is an anti-inflammatory measure that minimizes neutrophil activity and is regulated by membrane cholesterol. We tested the hypothesis that a hypercholesterolemic impairment of shear mechanotransduction alters the neutrophil flow behavior leading to microvascular dysfunction. Approach and Results-We examined the shear effects on the flow behavior of human leukocytes. When subjected to shearing during cone-plate viscometry, leukocyte suspensions exhibited parallel time-dependent reductions in viscosity and pseudopod activity. Shear-induced reductions in suspension viscosity were attenuated by membrane cholesterol enrichment. We also showed that enhanced pseudopod activity of leukocyte suspensions in 10% hematocrit significantly (P<0.05) raised the flow resistance of microvascular mimics. These results implicate an impaired neutrophil pseudopod retraction response to shear in hypercholesterolemic microvascular dysfunction. We confirmed this using near-infrared diffuse correlation spectroscopy to assess skeletal muscle blood flow regulation in the hindlimbs of mice subjected to reactive hyperemia. Using a custom protocol for the mouse, we extrapolated an adjusted peak flow and time to adjusted peak flow to quantify the early phase of the blood flow recovery response during reactive hyperemia when shear mechanobiology likely has a maximal impact. Compared with mice on normal diet, hypercholesterolemic mice exhibited significantly (P<0.05) reduced adjusted peak flow and prolonged time to adjusted peak flow which correlated (r=0.4 and r=−0.3, respectively) with neutrophil shear responsiveness and were abrogated by neutropenia. Conclusions-These results provide the first evidence that the neutrophils contribute to tissue blood flow autoregulation.Moreover, a deficit in the neutrophil responsiveness to shear may be a feature of hypercholesterolemia-related microvascular dysfunction. This possibility is in line with reports 13,14 that an impaired neutrophil shear response raises microvascular resistance.Notably, an impaired control of neutrophil pseudopod activity by shear stress develops early during development of a hypercholesterolemic blood state in mice fed a high-fat diet (HFD). 15Considering the link between neutrophil pseudopod activity and tissue blood flow, we hypothesized that a deficit in membrane cholesterol-related regulation of neutrophils by shear contributes to microvascular dysfunction in hypercholesterolemia.We used real-time viscometry of leukocyte suspensions and microfluidics to link microvessel resistance to shear regulation of neutrophil flow behavior. We also used low-density lipoprotein receptor-deficient mice fed a normal diet (ND) or HFD to reveal a first correlative link between neutrophil shear sensitivity and in vivo tissue blood flow regulation. For this purpose, we tested the perfusion recovery responses of the posterior thigh muscles of mice subjected to transient blood flow occlusion (ie, reactive hyperemia [RH]). Conceivably, neutroph...

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supporting

confidence: 84%

Shear-Sensitive Regulation of Neutrophil Flow Behavior and Its Potential Impact on Microvascular Blood Flow Dysregulation in Hypercholesterolemia

Zhang

Cheng

Rowe

et al. 2014

ATVB

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“…Blood flow changes measured with DCS have been extensively validated against other techniques in animal and human studies (Yu et al 2005;Zhou et al 2009;Carp et al 2010;Durduran et al 2010;Kim et al 2010). More recently, our group and others have conducted animal and human (Yu et al 2007;Buckley et al 2009;Roche-Labarbe et al 2010) validation studies to show how DCS provides an absolute number that scales with blood flow. By combining the FDNIRS measure of SO 2 and the DCS measure of a CBF i , we can estimate CMRO 2i , as described in Roche-Labarbe et al (2010).…”

Section: Discussionmentioning

confidence: 99%

Regional and Hemispheric Asymmetries of Cerebral Hemodynamic and Oxygen Metabolism in Newborns

Lin

Dehaes

Roche-Labarbe

et al. 2012

Biomedical Optics and 3-D Imaging

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Understanding the evolution of regional and hemispheric asymmetries in the early stages of life is essential to the advancement of developmental neuroscience. By using 2 noninvasive optical methods, frequency-domain near-infrared spectroscopy and diffuse correlation spectroscopy, we measured cerebral hemoglobin oxygenation (SO 2 ), blood volume (CBV), an index of cerebral blood flow (CBF i ), and the metabolic rate of oxygen (CMRO 2i ) in the frontal, temporal, and parietal regions of 70 premature and term newborns. In concordance with results obtained using more invasive imaging modalities, we verified both hemodynamic (CBV, CBF i , and SO 2 ) and metabolic (CMRO 2i ) parameters were greater in the temporal and parietal regions than in the frontal region and that these differences increased with age. In addition, we found that most parameters were significantly greater in the right hemisphere than in the left. Finally, in comparing age-matched males and females, we found that males had higher CBF i in most cortical regions, higher CMRO 2i in the frontal region, and more prominent right--left CBF i asymmetry. These results reveal, for the first time, that we can detect regional and hemispheric asymmetries in newborns using noninvasive optical techniques. Such a bedside screening tool may facilitate early detection of abnormalities and delays in maturation of specific cortical areas.

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“…a correlation coefficient of r = 0.73 was obtained for eight subjects ( figure 3). A second DCS validation example was performed with very low birth-weight preterm infants [53]. The skull anatomy of this patient population permits us to probe a significant fraction of the cortex.…”

Section: Flow Validationmentioning

confidence: 99%

Direct measurement of tissue blood flow and metabolism with diffuse optics

Mesquita

Durdurán

et al. 2011

Phil. Trans. R. Soc. A.

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Diffuse optics has proven useful for quantitative assessment of tissue oxy-and deoxyhaemoglobin concentrations and, more recently, for measurement of microvascular blood flow. In this paper, we focus on the flow monitoring technique: diffuse correlation spectroscopy (DCS). Representative clinical and pre-clinical studies from our laboratory illustrate the potential of DCS. Validation of DCS blood flow indices in human brain and muscle is presented. Comparison of DCS with arterial spin-labelled MRI, xenon-CT and Doppler ultrasound shows good agreement (0.50 < r < 0.95) over a wide range of tissue types and source detector distances, corroborating the potential of the method to measure perfusion non-invasively and in vivo at the microvasculature level. Alloptical measurements of cerebral oxygen metabolism in both rat brain, following middle cerebral artery occlusion, and human brain, during functional activation, are also described. In both situations, the use of combined DCS and diffuse optical spectroscopy/near-infrared spectroscopy to monitor changes in oxygen consumption by the tissue is demonstrated. Finally, recent results spanning from gene expression-induced angiogenic response to stroke care and cancer treatment monitoring are discussed.

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Cerebral hemodynamics in preterm infants during positional intervention measured with diffuse correlation spectroscopy and transcranial Doppler ultrasound

Cited by 157 publications

References 52 publications

Shear-Sensitive Regulation of Neutrophil Flow Behavior and Its Potential Impact on Microvascular Blood Flow Dysregulation in Hypercholesterolemia

Shear-Sensitive Regulation of Neutrophil Flow Behavior and Its Potential Impact on Microvascular Blood Flow Dysregulation in Hypercholesterolemia

Regional and Hemispheric Asymmetries of Cerebral Hemodynamic and Oxygen Metabolism in Newborns

Direct measurement of tissue blood flow and metabolism with diffuse optics

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