1. Structural analysis of adventitial collagen to feature aging and aneurysm formation in human aorta 
Go Urabe, MD, Katsuyuki Hoshina, MD, PhD, Tomomasa Shimanuki, MS, Yasutomo Nishimori, MS, PhD, Tetsuro Miyata, MD, PhD, Juno Deguchi, MD, PhD 
Journal of Vascular Surgery 
Volume 63, Issue 5, Pages (May 2016)
DOI: /j.jvs
Copyright © 2016 Society for Vascular Surgery Terms and Conditions

2. Fig 1
a, Components of collagen fiber. Images of scanning electron microscopy (SEM) show collagen fiber at a lower magnification (×900) and collagen fibril at a higher magnification (×19,000). b, The left panel illustrates four levels of aorta and two levels of surgical samples under analysis. The table indicates sample localization for each analysis. AA, Ascending aorta; AAA, abdominal aortic aneurysm; 2D-FFT, two-dimensional fast Fourier transform; IMA, aorta at the level of inferior mesenteric artery; InfRA, aorta at 2 cm below renal artery; NANA, nonatherosclerotic nonaneurysmal; SMA, aorta at the level of superior mesenteric artery. c, The principle of analyzing retardation of collagen bundles with polarized light microscopy. After it is transformed into a linear polarized light with a wavelength of 546 nm through a polarizer, the light passes through birefringence specimen and is transformed into elliptically polarized light. The light is converted back with the Sénarmont compensator (quarter wavelength plate) into linear polarized light with an angle lag θ from the original linear polarized light. The analyzer was rotated until maximum darkness of the collagen bundle, and the angle rotated was θ. Retardation R (nm) was calculated by the equation R = λθ/180 (λ = 546 nm).
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2016 Society for Vascular Surgery Terms and Conditions

3. Fig 2
Adventitial collagen fibers in abdominal aorta visualized by scanning electron microscopy (SEM): bird's-eye (a) and cross-sectional (b) views show that collagen fibers formed rope-like bundles in nonatherosclerotic nonaneurysmal (NANA) young aortas and became unraveled and flattened in NANA old aortas. Collagen fibers in abdominal aortic aneurysm (AAA) were flat and almost completely disappeared with strand formation (×900). Collagen fibrils appeared similar among NANA young and old aortas and AAA, although the fibrils were fluffier in aortas with AAA (×19,000).
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2016 Society for Vascular Surgery Terms and Conditions

4. Fig 3
Correlation between orientation of adventitial collagen determined by two-dimensional fast Fourier transform (2D-FFT) and age at four levels of nonatherosclerotic nonaneurysmal (NANA) aortas. Orientation is expressed as the following indices: orientation variation (OV), orientation ratio (OR), and fiber bundle spacing (BS). These indices did not significantly correlate. AA, Ascending aorta; IMA, aorta at the level of inferior mesenteric artery; InfRA, aorta at 2 cm below renal artery; SMA, aorta at the level of superior mesenteric artery.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
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5. Fig 4
Comparison of orientation between nonatherosclerotic nonaneurysmal (NANA) old aortas (n = 5) and abdominal aortic aneurysm (AAA) (n = 11). Orientation is expressed as the following indices: orientation variation (OV), orientation ratio (OR), and fiber bundle spacing (BS). These indices did not statistically differ between NANA old aortas and AAA. IMA, Aorta at the level of inferior mesenteric artery; InfRA, aorta at 2 cm below renal artery; NS, not significant.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2016 Society for Vascular Surgery Terms and Conditions

6. Fig 5
Retardation of adventitial collagen fibrils at four levels of nonatherosclerotic nonaneurysmal (NANA) aortas. a, Correlation between retardation of NANA aortas and age. b, Comparison of retardation at four levels of NANA aortas. Retardation at level of inferior mesenteric artery (IMA) was statistically lower than that at other levels. AA, Ascending aorta; InfRA, aorta at 2 cm below renal artery; SMA, aorta at the level of superior mesenteric artery.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2016 Society for Vascular Surgery Terms and Conditions

7. Fig 6
Comparison of retardation between nonatherosclerotic nonaneurysmal (NANA) aortas and aortas with abdominal aortic aneurysm (AAA) at levels of infrarenal aorta (InfRA) and inferior mesenteric artery (IMA). Retardation of AAA was statistically lower than that in NANA old aortas.
Journal of Vascular Surgery  , DOI: ( /j.jvs )
Copyright © 2016 Society for Vascular Surgery Terms and Conditions