Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
Cr
Ca
LRa
M
Ao
A
Elastin
Collagen
LDL
(d)
a
b
B
Elastin
Collagen
LDL
FIgurE 13.9
(
See color insert.
) LDL binds to the atherosclerosis-susceptible renal artery ostial diverter at the
aortic entrance to the renal artery. (a, b, c) Histological analysis. Sagital sections of renal diverter stained with
Masson's trichrome stain (a, b) for collagen (blue) and smooth muscle (red), and Movat stain (green) for proteo-
glycans (c). The caudal aspect (Ca) of the renal ostium (a) is thickened, angulated, and more rigid than the cranial
aspect (Cr). Both the intimal (rectangle) and medial (
M
) layers of the caudal renal ostium are thickened, forming a
flow diverter at the entrance to the renal artery. The thickened intimal layer on the caudal side of the renal ostium
forms an elongated cap (rectangle in a). A zone of proteoglycan enrichment (c, green) just below the surface of the
caudal ostium surrounds a densely collagenous core (b, blue) in the intimal “fibrous cap”-like structure. (a) Scale
bar = 500 μm; (b and c) Scale bars = 10 μm. (d) LDL binding to renal diverter microstructural components assessed
by two-photon multimodal microscopy. (d) Tiled (9 × 9) two-photon maximum projection of z-series images
through 180 μm of the luminal surface of the aortic entrance to the left renal artery. Merged image. Collagen SHG is
green, elastin autofluorescence is red, and Alexa 647-LDL is blue. LDL binds eccentrically to the collagen-enriched,
elastin-poor, atherosclerosis-susceptible, caudal side of the renal ostium. The tiles (A) and (B) outlined in the cranial
and caudal regions of the renal ostium in (d) are shown to the right in (A) and (B), respectively. Scale bar = 1 mm.
(Right) Z-series images at 0-124 μm from the luminal surface of the aortic wall, for tiles (A) and (B), respectively.
Elastin autofluorescence is red, collagen SHG is green, and Alexa 647-LDL fluorescence is white. Collagen is enriched
in the caudal compared to the cranial ostium. LDL binding is also greatly enhanced in the caudal compared to the
cranial ostium. LDL binding to the surface occurs prior to the appearance of collagen at both the cranial and cau-
dal sites, but overlaps to a considerable extent with collagen in the caudal ostium. Scale bars = 250 μm. (Reprinted
from
Atherosclerosis
211, Neufeld, E. B. et al. The renal artery ostium flow diverter: Structure and potential role in
atherosclerosis, 153-158, Copyright (2010), with permission from Elsevier Ireland LTD.)
[39], as noted above. These studies have shown that arterial branch points are predisposed to athero-
sclerotic lesion formation due to the intrinsic macromolecular composition required for structural
integrity at these sites.
13.7 investigations of the Diseased Vascular Wall
Nonlinear optical microscopy has been used to expand our current understanding of disease processes
that occur in the arterial wall, including atherosclerotic disease progression, cardiomyopathy, and
