SYNCHROTRON‐BASED ANGIOGRAPHY FOR INVESTIGATION OF THE REGULATION OF VASOMOTOR FUNCTION IN THE MICROCIRCULATION<i> IN VIVO</i>

Shirai, Masamitsu; Schwenke, Daryl O.; Eppel, Gabriela Alejandra; Evans, Roger G.; Edgley, Amanda J.; Tsuchimochi, Hirotsugu; Umetani, Keiji; Pearson, James T.

doi:10.1111/j.1440-1681.2008.05073.x

Cited by 31 publications

(29 citation statements)

References 60 publications

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“…Microangiography using synchrotron radiation has recently been applied to a range of vascular beds (27), including the liver (14), lungs (25,26), brain (13, 18 -20, 30), and heart (12). One of the major the strengths of the technique is that there is no geometric magnification of vessels.…”

Section: Discussionmentioning

confidence: 99%

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Eppel¹,

Jacono²,

Shirai³

et al. 2009

American Journal of Physiology-Renal Physiology

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Eppel GA, Jacono DL, Shirai M, Umetani K, Evans RG, Pearson JT. Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation. Am J Physiol Renal Physiol 296: F1023-F1031, 2009. First published March 4, 2009 doi:10.1152/ajprenal.90499.2008.-We have developed a new method for contrast microangiography of the rat renal circulation using synchrotron radiation. The method was applied to determine responses of the renal arterial vasculature to angiotensin II and electrical stimulation of the renal nerves (RNS). Iodinated contrast agent was administered directly into the renal artery of pentobarbital-anesthetized rats before and during 1) intravenous infusion of angiotensin II (1.6 g ⅐ kg Ϫ1 ⅐ min Ϫ1 ) or 2) its vehicle, or 3) RNS at 2 Hz. Images were obtained at 30 Hz, before and during these treatments, and vascular caliber was determined by use of a newly developed algorithm described herein. Up to four levels of branching could be observed simultaneously along the arterial tree, comprising vessels with resting diameter of 28 -400 m. Vessel diameter was not significantly altered by vehicle infusion (ϩ3.1 Ϯ 3.5% change) but was significantly reduced by angiotensin II (Ϫ24.3 Ϯ 3.4%) and RNS (Ϫ17.1 Ϯ 3.8%). Angiotensin II-induced vasoconstriction was independent of vessel size, but RNS-induced vasoconstriction was greatest in vessels with a resting caliber of 100 -200 m and least in vessels with a resting caliber 40 -100 m. In conclusion, the method we describe herein provides a new approach for assessing responses of the renal arterial circulation to vasoactive factors along several orders of branching.angiography; angiotensin II; vascular caliber; kidney circulation; renal nerves RENAL VASCULAR TONE IS A CRITICAL controller of renal perfusion, glomerular filtration rate, and tubular function (21) and thus long-term regulation of body fluid homeostasis (9). Many available methodologies allow quantification of changes in the caliber of resistance vessels in vivo, but all have important limitations. For example, vascular casting techniques allow quantification of vascular caliber at multiple points along the renal vascular tree, potentially allowing analysis of regulation of blood flow within networks of blood vessels in the kidney (4, 5). But an important disadvantage of this approach is that measurements can only be made at a single time point so that the effects of vasoactive factors can only be inferred from cross-sectional comparisons between blood vessels in different animals. Real-time analysis of vascular caliber (17) and capillary blood velocity (33) within the kidney has been achieved with intravital microscopy, but currently the measurements derived from such techniques are limited to single points along an identified blood vessel. Magnetic resonance imaging and X-ray microtomographic techniques currently lack the spatial and/or temporal resolution required for real-time analysis of resistance vessel caliber in the kidney in vivo (1).Herein we present a new approach that overcom...

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Section: Discussionmentioning

confidence: 99%

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Eppel¹,

Jacono²,

Shirai³

et al. 2009

American Journal of Physiology-Renal Physiology

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“…[3][4][5] In essence, SR produces superior image quality because, first, the extremely high intensity of radiation emitted from the synchrotron storage ring produces extremely bright light. This allows greater X-ray penetration of thick tissues, greater image contrast, and greater X-ray flux during short exposure time to produce sharp and blur-free images.…”

Section: Sr Microangiographymentioning

confidence: 99%

“…In this approach, high-resolution imaging is compromised for the rapid imaging of a large area (essential for large animal or patient imaging). 5 The second approach, single-energy temporal subtraction, uses a single energy (monochromatic) of SR to record X-ray images just above the K-edge. To emphasize the contrast agent contained in blood vessels, 14,20 a background image without contrast agent is subtracted from the vessel images in stationary animals.…”

Section: Sr Microangiographymentioning

confidence: 99%

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Synchrotron Radiation Imaging for Advancing Our Understanding of Cardiovascular Function

Shirai

Schwenke

Tsuchimochi

et al. 2013

Circulation Research

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Synchrotron radiation (SR) is increasingly being used for micro-level and nano-level functionalimaging in in vivo animal experiments. This review focuses on the methodology that enables repeated and regional assessment of vessel internal diameter and flow in the resistance vessels of different organ systems. In particular, SR absorption microangiography approaches offer unique opportunities for real-time in vivo vascular imaging in small animals, even during dynamic motion of the heart and lungs. We also describe recent progress in the translation of multiple phase-contrast imaging techniques from ex vivo to in vivo smallanimal studies. Furthermore, we also review the utility of SR for multiple pinpoint (dimensions 0.2×0.2 mm) assessments of myocardial function at the cross-bridge level in different regions of the heart using small-angle X-ray scattering, resulting from increases in SR flux at modern facilities. Finally, we present cases for the use of complementary SR approaches to study cardiovascular function, particularly the pathological changes associated with disease using small-animal models. -times brighter than laboratory or medical X-ray sources). This brightness is attributable to the fine collimation of the X-ray beam (http:// www.spring8.or.jp/en/about_us/whats_sr/generation_sr/).At SPring-8 in Japan, which is one of the largest SR facilities in the world, one of the smallest beam sizes is ≈2 mm horizontally by 0.4 mm vertically at 40 m from the X-ray source. This divergence is much smaller than that of most laboratory lasers. The X-ray beam is further collimated with focusing optics, so that it is <0.2 mm in diameter at the sample, concentrating a large number of X-ray photons on the sample. There are tens of SR facilities around the world, most of which are available for public access (for details on SR facilities, SR characteristics, and other science applications, http://www.lightsources.org/cms/).The intense X-ray beam from the synchrotron beamlines only can be used in metal-shielded hutches. X-ray image formation and acquisition have to be performed under remote control, including operations to inject contrast medium into an animal or to stop artificial ventilation temporarily. Despite this restriction, when the animal is closely monitored, the experiment can be performed smoothly. At SR medical imaging beamlines important infrastructure for animal experiments such as an animal house, and biology and chemistry preparation laboratories are an essential capability for the experiments described in this review. SR Absorption MicroangiographyThe vascular smooth muscle tone of arterioles is meticulously modulated via multiple mechanistic pathways, including, but not limited to, the vessel endothelium, the vascular smooth muscle, and neurohumoral stimuli to regulate resistance to flow and, hence, to optimize regional blood flow. Impairment of any of these regulatory systems has the potential to adversely impact on the vascular control of blood flow and, thus, impair the homeostatic control...

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“…6,7 Synchrotron radiation angiography (SRA) may represent a novel solution to directly and dynamically monitor MCAO. 8 In the present study, we used SRA to examine if the coating length was critical for producing a highly reproducible stroke model. …”

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confidence: 99%

Effect of Suture Properties on Stability of Middle Cerebral Artery Occlusion Evaluated by Synchrotron Radiation Angiography

Guan

Wang

Yuan

et al. 2012

Stroke

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Background and Purpose-The intraluminal suture technique for producing middle cerebral artery occlusion in rodents is the most commonly used method for modeling focal cerebral ischemia associated with clinical ischemic stroke. Synchrotron radiation angiography may provide a novel solution to directly monitor the success of middle cerebral artery occlusion. Methods-Twenty adult Sprague-Dawley rats for middle cerebral artery occlusion models were prepared randomly with different suture head silicone coating. In vivo imaging was performed at beam line BL13W1, Shanghai Synchrotron Radiation Facility, Shanghai, China. Results-Silicone-coated suture was superior to uncoated suture for producing consistent brain infarction. Additionally, silicone coating length was an important variable controlling the extent of the ischemic lesion: infarcts affected predominantly the caudate-putamen with large variability (Ͻ2 mm), both the cortex and caudate-putamen (2-3.3 mm), and most of the hemisphere, including the hypothalamus (Ͼ3.3 mm). Conclusions-Synchrotron radiation angiography provides a useful tool to observe hemodynamic changes after middle cerebral artery occlusion, and the physical properties of suture are critical to the success of the middle cerebral artery occlusion model. (Stroke. 2012;43:888-891.)Key Words: angiography Ⅲ middle cerebral artery occlusion Ⅲ synchrotron radiation T he focal cerebral ischemia model involves the occlusion of the middle cerebral artery (MCAO) and typically results in localized brain infarction, which recapitulates many of the pathophysiological and histopathologic features of stroke. The most common technique for MCAO is the intraluminal filament model. 1 However, 1 limitation of the suture model is its high variability in infarct size. 2 Factors that contribute to such variation include differences in animal strain and weight, method of anesthesia, blood pressure, brain and body temperature, brain vascular anatomy, suture material, duration, and site of occlusion. Physical properties of the filament are important because it is the key factor that affects lesion volume 3 ; however, there is no direct evidence to confirm this principle. 4,5 Regional cerebral blood flow can be measured using autoradiography and laser Doppler flowmetry to confirm successful MCAO, but neither method can dynamically monitor changes of cerebral blood flow in deeper tissue during ischemia-reperfusion. 6,7 Synchrotron radiation angiography (SRA) may represent a novel solution to directly and dynamically monitor MCAO. 8 In the present study, we used SRA to examine if the coating length was critical for producing a highly reproducible stroke model. Materials and Methods Experimental GroupsAnimal procedures were approved by the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University, Shanghai, China. Twenty male Sprague-Dawley rats (SLAC, Shanghai, China) weighing 270 to 350 g were divided into 4 groups randomly (nϭ5/group). The sutures with different physical properties were used in 4 groups t...

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SYNCHROTRON‐BASED ANGIOGRAPHY FOR INVESTIGATION OF THE REGULATION OF VASOMOTOR FUNCTION IN THE MICROCIRCULATION IN VIVO

Cited by 31 publications

References 60 publications

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Contrast angiography of the rat renal microcirculation in vivo using synchrotron radiation

Synchrotron Radiation Imaging for Advancing Our Understanding of Cardiovascular Function

Effect of Suture Properties on Stability of Middle Cerebral Artery Occlusion Evaluated by Synchrotron Radiation Angiography

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