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Feasibility Study of Ex Ovo Chick Chorioallantoic Artery Model for Investigating Pulsatile Variation of Arterial Geometry.

Nam KH, Kim J, Ra G, Lee CH, Paeng DG - PLoS ONE (2015)

Bottom Line: The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results.In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images.The CAM artery model with the spectral analysis method is a useful in vivo experimental model for studying pulsatile variation in arterial geometry.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea.

ABSTRACT
Despite considerable research efforts on the relationship between arterial geometry and cardiovascular pathology, information is lacking on the pulsatile geometrical variation caused by arterial distensibility and cardiomotility because of the lack of suitable in vivo experimental models and the methodological difficulties in examining the arterial dynamics. We aimed to investigate the feasibility of using a chick embryo system as an experimental model for basic research on the pulsatile variation of arterial geometry. Optical microscope video images of various arterial shapes in chick chorioallantoic circulation were recorded from different locations and different embryo samples. The high optical transparency of the chorioallantoic membrane (CAM) allowed clear observation of tiny vessels and their movements. Systolic and diastolic changes in arterial geometry were visualized by detecting the wall boundaries from binary images. Several to hundreds of microns of wall displacement variations were recognized during a pulsatile cycle. The spatial maps of the wall motion harmonics and magnitude ratio of harmonic components were obtained by analyzing the temporal brightness variation at each pixel in sequential grayscale images using spectral analysis techniques. The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results. In addition, mapping the phase angle of the fundamental frequency identified the regional variations in the wall motion directivity and phase shift. Regional variations in wall motion phase angle and fundamental-to-second harmonic ratio were remarkable near the bifurcation area. In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images. The CAM artery model with the spectral analysis method is a useful in vivo experimental model for studying pulsatile variation in arterial geometry.

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Photo of a chick embryo CAM at HH stage 36 (10 days of incubation).Transparent CAM with well developed vascular network over the yolk sac. An artery marked with arrows appears darker than vein marked with an asterisk.
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pone.0145969.g001: Photo of a chick embryo CAM at HH stage 36 (10 days of incubation).Transparent CAM with well developed vascular network over the yolk sac. An artery marked with arrows appears darker than vein marked with an asterisk.

Mentions: The imaging system consists of a vertical microscope (Nikon ECLIPSE E200, Japan) with a halogen lamp and a digital video camera recorder (Sony HDR-XR520, Japan). An objective lens with a 4× magnification (numerical aperture = 0.10) was used. It is reported that the CAM is formed at 4 to 5 days of incubation, and increases in size and becomes more vascularized until day 11 when its growth rate remained minimal [29]. The video images of the CAM arteries were captured at a frame rate of 120 Hz for 3 seconds during well vascularized stages (HH stages 34–37 corresponding to 8–11 days of incubation). The pixel size of the microscopic images was approximately 2.4 μm/pixel. Imaging was performed at room temperature (25°C) in a thermostatic room. Fig 1 shows a typical image of the CAM vascular network at HH stage 36 (10 days of incubation). A main artery is bifurcated and further divided into numerous branches. The arteries can be easily identified from veins by motility and blood color of arteries. The microscopic artery images were captured from the downstream of the second level bifurcation because the CAM artery started from the bottom of the ex ovo culture system and was usually observed to float flat on the extraembryonic surface after the second-level bifurcation. Various images of arteries were obtained from more than 20 embryo samples, and the analysis results from seven representative video images were displayed.


Feasibility Study of Ex Ovo Chick Chorioallantoic Artery Model for Investigating Pulsatile Variation of Arterial Geometry.

Nam KH, Kim J, Ra G, Lee CH, Paeng DG - PLoS ONE (2015)

Photo of a chick embryo CAM at HH stage 36 (10 days of incubation).Transparent CAM with well developed vascular network over the yolk sac. An artery marked with arrows appears darker than vein marked with an asterisk.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4696805&req=5

pone.0145969.g001: Photo of a chick embryo CAM at HH stage 36 (10 days of incubation).Transparent CAM with well developed vascular network over the yolk sac. An artery marked with arrows appears darker than vein marked with an asterisk.
Mentions: The imaging system consists of a vertical microscope (Nikon ECLIPSE E200, Japan) with a halogen lamp and a digital video camera recorder (Sony HDR-XR520, Japan). An objective lens with a 4× magnification (numerical aperture = 0.10) was used. It is reported that the CAM is formed at 4 to 5 days of incubation, and increases in size and becomes more vascularized until day 11 when its growth rate remained minimal [29]. The video images of the CAM arteries were captured at a frame rate of 120 Hz for 3 seconds during well vascularized stages (HH stages 34–37 corresponding to 8–11 days of incubation). The pixel size of the microscopic images was approximately 2.4 μm/pixel. Imaging was performed at room temperature (25°C) in a thermostatic room. Fig 1 shows a typical image of the CAM vascular network at HH stage 36 (10 days of incubation). A main artery is bifurcated and further divided into numerous branches. The arteries can be easily identified from veins by motility and blood color of arteries. The microscopic artery images were captured from the downstream of the second level bifurcation because the CAM artery started from the bottom of the ex ovo culture system and was usually observed to float flat on the extraembryonic surface after the second-level bifurcation. Various images of arteries were obtained from more than 20 embryo samples, and the analysis results from seven representative video images were displayed.

Bottom Line: The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results.In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images.The CAM artery model with the spectral analysis method is a useful in vivo experimental model for studying pulsatile variation in arterial geometry.

View Article: PubMed Central - PubMed

Affiliation: Interdisciplinary Postgraduate Program in Biomedical Engineering, Jeju National University, Jeju, South Korea.

ABSTRACT
Despite considerable research efforts on the relationship between arterial geometry and cardiovascular pathology, information is lacking on the pulsatile geometrical variation caused by arterial distensibility and cardiomotility because of the lack of suitable in vivo experimental models and the methodological difficulties in examining the arterial dynamics. We aimed to investigate the feasibility of using a chick embryo system as an experimental model for basic research on the pulsatile variation of arterial geometry. Optical microscope video images of various arterial shapes in chick chorioallantoic circulation were recorded from different locations and different embryo samples. The high optical transparency of the chorioallantoic membrane (CAM) allowed clear observation of tiny vessels and their movements. Systolic and diastolic changes in arterial geometry were visualized by detecting the wall boundaries from binary images. Several to hundreds of microns of wall displacement variations were recognized during a pulsatile cycle. The spatial maps of the wall motion harmonics and magnitude ratio of harmonic components were obtained by analyzing the temporal brightness variation at each pixel in sequential grayscale images using spectral analysis techniques. The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results. In addition, mapping the phase angle of the fundamental frequency identified the regional variations in the wall motion directivity and phase shift. Regional variations in wall motion phase angle and fundamental-to-second harmonic ratio were remarkable near the bifurcation area. In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images. The CAM artery model with the spectral analysis method is a useful in vivo experimental model for studying pulsatile variation in arterial geometry.

Show MeSH
Related in: MedlinePlus