Flow visualization in isolated transparent natural blood vessels

Karino, Takeshi; Motomiya, Mineo

doi:10.3233/bir-1983-20202

Cited by 64 publications

(13 citation statements)

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“…6 -7 More recently, we have developed a new technique to prepare isolated transparent natural blood vessels from animals and humans post-mortem. 8 This has, for the first time, enabled us to study the exact flow patterns and distributions of fluid velocity and shear rate existing in var-…”

Section: Stroke Vol 15 No I 1984mentioning

confidence: 99%

Flow patterns in the human carotid artery bifurcation.

Motomiya¹,

Karino²

1984

Stroke

225

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SUMMARY To elucidate the connection between blood flow and the localized genesis and development of atherosclerosis and thrombosis at the human carotid artery bifurcation, detailed studies of the flow patterns and distributions of fluid velocity and wall shear rate in this region were carried out using a transparent segment of the carotid artery, prepared from a human subject postmortem, and cinemicrographic techniques.It

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Section: Stroke Vol 15 No I 1984mentioning

confidence: 99%

Flow patterns in the human carotid artery bifurcation.

Motomiya¹,

Karino²

1984

Stroke

225

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“…The strikingly nonrandom distribution of the earliest lesions of atherosclerosis in both humans and experimental animals has suggested to many that hemodynamic forces might be acting as local "biomechanical risk factors"; however, the exact nature of the biomechanical stimuli involved and their influences on EC pathobiology remain ill-defined (4)(5)(6). Arterial bifurcations and curvatures, where disturbed flow patterns (flow separation, flow reversal, low amplitude, and fluctuating wall shear stresses) occur, typically are "lesion-prone areas," whereas geometries associated with uniform laminar flow (oscillatory without flow reversal) and relatively constant (time-averaged) wall shear stresses, such as the straight tubular portions of the aorta and its primary tributaries, tend to be "lesion-protected areas" (7)(8)(9). Interestingly, these patterns are retained even in genetically modified animals in which systemic risk factors, such as markedly elevated levels of atherogenic plasma lipoproteins, are present (10).…”

mentioning

confidence: 99%

Identification of vascular endothelial genes differentially responsive to fluid mechanical stimuli: cyclooxygenase-2, manganese superoxide dismutase, and endothelial cell nitric oxide synthase are selectively up-regulated by steady laminar shear stress.

Topper

Cai

Falb

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

782

499

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Early atherosclerotic lesions develop in a topographical pattern that strongly suggests involvement of hemodynamic forces in their pathogenesis. We hypothesized that certain endothelial genes, which exhibit differential responsiveness to distinct fluid mechanical stimuli, may participate in the atherogenic process by modulating, on a local level within the arterial wall, the effects of systemic risk factors. A differential display strategy using cultured human endothelial cells has identified two genes, manganese superoxide dismutase and cyclooxygenase-2, that exhibit selective and sustained up-regulation by steady laminar shear stress (LSS). Turbulent shear stress, a nonlaminar fluid mechanical stimulus, does not induce these genes. The endothelial form of nitric oxide synthase also demonstrates a similar LSSselective pattern of induction. Thus, three genes with potential atheroprotective (antioxidant, antithrombotic, and antiadhesive) activities manifest a differential response to distinct fluid mechanical stimuli, providing a possible mechanistic link between endothelial gene expression and early events in atherogenesis. The activities of these and other LSSresponsive genes may have important implications for the pathogenesis and prevention of atherosclerosis.Vascular endothelium, the single-cell-thick lining of the cardiovascular system, forms a multifunctional, dynamically mutable interface, that is responsive to a variety of pathophysiologic stimuli. Dysfunction of endothelial cells (EC), induced by systemic biochemical risk factors (e.g., hypercholesterolemia, hyperhomocysteinemia, and diabetes), is thought to play a critical role in the development of atherosclerotic vascular disease and its clinical complications (1-3). The strikingly nonrandom distribution of the earliest lesions of atherosclerosis in both humans and experimental animals has suggested to many that hemodynamic forces might be acting as local "biomechanical risk factors"; however, the exact nature of the biomechanical stimuli involved and their influences on EC pathobiology remain ill-defined (4-6). Arterial bifurcations and curvatures, where disturbed flow patterns (flow separation, flow reversal, low amplitude, and fluctuating wall shear stresses) occur, typically are "lesion-prone areas," whereas geometries associated with uniform laminar flow (oscillatory without flow reversal) and relatively constant (time-averaged) wall shear stresses, such as the straight tubular portions of the aorta and its primary tributaries, tend to be "lesion-protected areas" (7-9). Interestingly, these patterns are retained even in genetically modified animals in which systemic risk factors, such as markedly elevated levels of atherogenic plasma lipoproteins, are present (10). These observations indicate that EC may respond differentially to their local fluid mechanical environment, and thus contribute to the characteristic pattern of atherosclerotic lesion development.Although the molecular mechanisms responsible for atherosclerotic lesion initiati...

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“…Then the transparent stenosis was mounted to a head-tank overflow perfusion system to observe its flow pattern. The perfusion fluid used in this flow study was methyl salicylate [8] (oil of winter green) to keep the arterial segment transparent. A small amount of neutrally buoyant latex microspheres with diameters of 50-120 μm (Duke Scientific Corp., Palo Alto, CA) was added to visualize the flow in the stenosis.…”

Section: Model Flow Studymentioning

confidence: 99%

“…A stenosis with 75% area constriction was introduced to the artery segment by using a length of 3-0 silk suture. The artery segment with the stenosis was rendered transparent according to the technique described by Karino et al [8] . Then the transparent stenosis was mounted to a head-tank overflow perfusion system to observe its flow pattern.…”

Section: Model Flow Studymentioning

confidence: 99%

Ex vitro experimental study on concentration polarization of macromolecules (LDL) at an arterial stenosis

et al. 2007

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To verify the previous theoretical prediction that the disturbed flow distal to a stenosis enhances lipid accumulation at the blood/arterial wall interface, we designed a canine carotid arterial stenosis model and measured ex vitro the luminal surface concentration of bovine serum albumin (as a tracer macromolecule) by directly taking liquid samples from the luminal surface of the artery. The experimental results showed that due to the presence of a filtration flow, the luminal surface albumin concentration c(w) was higher than the bulk concentration c(0) as predicted by our theory. The measurement revealed that the luminal surface concentration of macromolecules was indeed enhanced significantly in regions of the disturbed flow. At Re = 50, the relative luminal surface concentration c(w)/c(0) was 1.66 +/- 0.10 in the vortex region, while the c(w)/c(0) was 1.37 +/- 0.06 in the laminar flow region. When Re increased to 100, the c(w)/c(0) in the vortex flow region and the laminar flow region reduced to 1.39 +/- 0.07 and 1.24 +/- 0.04, respectively. The effect of the filtration rate, v(w), on the luminal surface concentration of albumin was remarkably apparent. At Re = 50 and 100, when v(w) = 8.9 +/- 1.7 x 10(-6) cm/s, c(w) in the vortex region was 77% and 52% higher than c(0) respectively, meanwhile when v(w) = 4.8 +/- 0.6 x 10(-6) cm/s, c(w) in the vortex region was only 66% and 39% higher than c(0) respectively. In summary, the present study has provided further experimental evidence that concentration polarization can occur in the arterial system and fluid layer with highly concentrated lipids in the area of flow separation point may be responsible for the formation and development of atherosclerosis.

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Flow visualization in isolated transparent natural blood vessels

Cited by 64 publications

References 0 publications

Flow patterns in the human carotid artery bifurcation.

Flow patterns in the human carotid artery bifurcation.

Identification of vascular endothelial genes differentially responsive to fluid mechanical stimuli: cyclooxygenase-2, manganese superoxide dismutase, and endothelial cell nitric oxide synthase are selectively up-regulated by steady laminar shear stress.

Ex vitro experimental study on concentration polarization of macromolecules (LDL) at an arterial stenosis

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