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Global Translational Medicine Quantification of atherosclerosis

to enhance automated quantification. It is important to perform histology and immunostaining to compare
note that it is not appropriate to report percent lesion area lesion composition [1,13] .
that is normalized using luminal area for aortic root cross-
sections. In contrast to the normalization of lesion area Acknowledgments
by intimal surface area for the en face analysis, luminal None.
area cannot reflect the true surface areas in the aortic root
cross-sections. Therefore, most researchers report absolute Funding
lesion areas, as we also recommend. Many articles show The authors’ research work on atherosclerosis is supported
one representative image for the aortic root, which does by the National Heart, Lung, and Blood Institute of
not reflect appropriately the lesion measurements. We the National Institutes of Health under award number
recommend showing images of the serial sections used for
quantification of atherosclerosis, as shown in Figure 2C. R01HL139748. The content in this manuscript is solely
While we suggest measuring lesion areas on 6–9 sections the responsibility of the authors and does not necessarily
of each aortic root, we also recommend reporting the data represent the official views of the National Institutes of
Health.
as per the example shown in Figure 2D.
4. Summary Conflict of interest

Both en face analysis and aortic root cross-section methods None.
have been the classic approaches for atherosclerotic Author contributions
lesion size quantification. In addition to what we have
recommended above, it is important to consider some Conceptualization: Alan Daugherty, Hong S. Lu
factors for experimental design and data analysis. We Data curation: Hui Chen, Deborah A. Howatt, Michael K.
recommend taking the following factors into consideration: Franklin, Naofumi Amioka
i. En face analysis provides quantification of two- Supervision: Alan Daugherty, Hong S. Lu
dimensional lesion area without considering the Validation: Alan Daugherty, Hong S. Lu
thickness of lesions. To overcome this shortcoming, Visualization: Hui Chen, Hisashi Sawada, Hong S. Lu
cholesterol content can be measured, for example, Writing – original draft: Hui Chen, Hong S. Lu
using chromatography. This is particularly insightful Writing – review & editing: All authors
if the lesions are thick. Furthermore, we expect in the
near future that the high resolution of the advanced References
micro-CT may make it possible to measure the full 1. Daugherty A, Tall AR, Daemen M, et al., 2017,
three-dimensional volume of plaques in both the Recommendation on design, execution, and reporting of
aorta and the aortic root. animal atherosclerosis studies: A scientific statement from
ii. Atherosclerotic lesions are initiated in the aortic the American heart association. Arterioscler Thromb Vasc
root, ascending aorta, and arch regions, but hardly Biol, 37: e131–e157.
detectable in the descending thoracic and abdominal https://doi.org/10.1161/atv.0000000000000062
regions within 8–12 weeks of Western diet feeding. 2. Wu C, Daugherty A, Lu HS, 2019, Updates on approaches
We recommend measuring and comparing lesions for studying atherosclerosis. Arterioscler Thromb Vasc Biol,
in a region-specific manner. These will help discover 39: e108–e117.
potential region-specific differences.
iii. In addition to the aorta, atherosclerosis can also be 3. Lu H, Daugherty A, 2015, Atherosclerosis. Arterioscler
profound in the innominate and left carotid arteries Thromb Vasc Biol, 35: 485–491.
when the mice are fed a Western-type diet for a 4. Lu H, Howatt DA, Balakrishnan A, et al., 2016,
prolonged duration such as 12 weeks (or 3 months). Hypercholesterolemia induced by a PCSK9 gain-of-function
We recommend including the proximal portions of mutation augments angiotensin II-induced abdominal
these two arteries (such as 1 mm from the orifice) for aortic aneurysms in C57BL/6 mice. Arterioscler Thromb
en face analysis. Vasc Biol, 36: 1753–1757.
iv. Evaluation of human and animal atherosclerosis has https://doi.org/10.1161/atvbaha.116.307613
provided evidence that lesion composition, rather 5. Roche-Molina M, Sanz-Rosa D, Cruz FM, et al., 2015,
than lesion size, may be the primary factor defining Induction of sustained hypercholesterolemia by single
the risk of cardiovascular consequences [1,11,12] . In adeno-associated virus-mediated gene transfer of mutant
addition to lesion size, it would be important to hPCSK9. Arterioscler Thromb Vasc Biol, 35: 50–59.

Volume 1 Issue 1 (2022) 5 https://doi.org/10.36922/gtm.v1i1.76