A Simple “Streak Length Method” for Quantifying and Characterizing Red Blood Cell Velocity Profiles and Blood Flow in Rat Skeletal Muscle Arterioles

Al‐Khazraji, Baraa K.; Novielli, Nicole; Goldman, Daniel; Medeiros, Philip J.; Jackson, Dwayne N.

doi:10.1111/j.1549-8719.2012.00165.x

Cited by 25 publications

(55 citation statements)

References 27 publications

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“…Centerline RBC velocities were acquired by taking multiple centerline streak length (camera exposure: 10 -20 ms depending on RBC velocity) measurements using ImageJ software (manual; ImageJ 1.43 u; National Institutes of Health, Bethesda, MD). Mean RBC velocity was calculated by correcting centerline streak lengths with a velocity ratio factor (Vratio) previously determined based on the arteriolar diameter of interest, where Vratio ϭ (0.0071 ϫ diameter) ϩ 1.15 (1). Blood flow was calculated as a product of mean RBC velocity and vessel cross-sectional area.…”

Section: Rat Gluteus Maximus Skeletal Muscle Modelmentioning

confidence: 99%

Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia

Nyberg

Al‐Khazraji

Mortensen

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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During skeletal muscle contractions, the concentration of ATP increases in muscle interstitial fluid as measured by microdialysis probes. This increase is associated with the magnitude of blood flow, suggesting that interstitial ATP may be important for contraction-induced vasodilation. However, interstitial ATP has solely been described to induce vasoconstriction in skeletal muscle. To examine whether interstitial ATP induces vasodilation in skeletal muscle and to what extent this vasoactive effect is mediated by formation of nitric oxide (NO) and prostanoids, three different experimental models were studied. The rat gluteus maximus skeletal muscle model was used to study changes in local skeletal muscle hemodynamics. Superfused ATP at concentrations found during muscle contractions (1-10 μM) increased blood flow by up to 400%. In this model, the underlying mechanism was also examined by inhibition of NO and prostanoid formation. Inhibition of these systems abolished the vasodilator effect of ATP. Cell-culture experiments verified ATP-induced formation of NO and prostacyclin in rat skeletal muscle microvascular endothelial cells, and ATP-induced formation of NO in rat skeletal muscle cells. To confirm these findings in humans, ATP was infused into skeletal muscle interstitium of healthy subjects via microdialysis probes and found to increase muscle interstitial concentrations of NO and prostacyclin by ~60% and ~40%, respectively. Collectively, these data suggest that a physiologically relevant elevation in interstitial ATP concentrations increases muscle blood flow, indicating that the contraction-induced increase in skeletal muscle interstitial [ATP] is important for exercise hyperemia. The vasodilator effect of ATP application is mediated by NO and prostanoid formation.

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Section: Rat Gluteus Maximus Skeletal Muscle Modelmentioning

confidence: 99%

Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia

Nyberg

Al‐Khazraji

Mortensen

et al. 2013

American Journal of Physiology-Regulatory, Integrative and Comp

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“…This stands in contrast to the bulk perfusion measurements acquired by laser Doppler perfusion imaging (9, 18, 43) and wide field applications of LSF (7, 18, 38). Second, where high resolution is available, such as in the recent development of optical imaging techniques including optical coherent tomography (13, 50), intravital microscopy of fluorescent particles (1, 30, 42), and multiphoton microscopy (24, 26), there are often limitations with respect to spatial coverage and the challenges of registering multiple fields of view. A similar difficulty is present in the more traditional microvascular tools of autocorrelation and dual-slit velocimeters (8, 46) in the experimental duration needed to capture hemodynamics throughout an entire network one vessel at a time.…”

Section: Discussionmentioning

confidence: 99%

Laser Speckle Flowmetry Method for Measuring Spatial and Temporal Hemodynamic Alterations Throughout Large Microvascular Networks

et al. 2012

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Objectives 1) Develop and validate laser speckle flowmetry (LSF) as a quantitative tool for individual microvessel hemodynamics in large networks. 2) Use LSF to determine if structural differences in the dorsal skinfold microcirculation (DSFWC) of C57BL/6 and BALB/c mice impart differential network hemodynamic responses to occlusion. Methods We compared LSF velocity measurements to known/measured velocities in vitro using capillary tube tissue phantoms and in vivo using mouse DSFWCs and cremaster muscles. Hemodynamic changes induced by feed arteriole occlusion were measured using LSF in DSFWCs implanted on C57BL/6 and BALB/c. Results In vitro, we found that the normalized speckle intensity (NSI) versus velocity linear relationship (R2≥0.97) did not vary with diameter or hematocrit and can be shifted to meet an expected operating range. In vivo, DSFWC and cremaster muscle preparations (R2=0.92 and 0.95, respectively) demonstrated similar linear relationships between NSI and centerline velocity. Stratification of arterioles into predicted collateral pathways revealed significant differences between C57BL/6 and BALB/c strains in response to feed arteriole occlusion. Conclusions These data demonstrate the applicability of LSF to intravital microscopy microcirculation preparations for determining both relative and absolute hemodynamics on a network-wide scale while maintaining the resolution of individual microvessels.

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“…The animal preparation and IVVM techniques used are described in detail in Ref. . Also described in Ref.…”

Section: Experimental Methodsmentioning

confidence: 99%

Estimating blood flow in skeletal muscle arteriolar trees reconstructed from in vivo data using the Fry approach

et al. 2017

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A Simple “Streak Length Method” for Quantifying and Characterizing Red Blood Cell Velocity Profiles and Blood Flow in Rat Skeletal Muscle Arterioles

Abstract: We present a means for quantifying blood flow in continuously branching skeletal muscle arterioles. Further, we provide an equation for calculating velocity ratios based on arteriolar diameter, which may be used by others for blood flow calculations.

Cited by 25 publications

References 27 publications

Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia

Effect of extraluminal ATP application on vascular tone and blood flow in skeletal muscle: implications for exercise hyperemia

Laser Speckle Flowmetry Method for Measuring Spatial and Temporal Hemodynamic Alterations Throughout Large Microvascular Networks

Estimating blood flow in skeletal muscle arteriolar trees reconstructed from in vivo data using the Fry approach

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