Research ArticleHEALTH AND MEDICINE

Raman spectroscopy imaging reveals interplay between atherosclerosis and medial calcification in the human aorta

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Science Advances  06 Dec 2017:
Vol. 3, no. 12, e1701156
DOI: 10.1126/sciadv.1701156
  • Fig. 1 Univariate Raman spectroscopy images of the cross section of a representative nonatherosclerotic aorta (65 years old).

    (A) Representative spectra rich in specific aortic components. (B) Univariate heat maps of the entire cross section of a nonatherosclerotic aorta were plotted according to the signature peaks listed. (C and D) High-resolution maps at the intima-media interface (C) and within the media (D) were also plotted. Merge refers to a composite image of all the univariate heat maps. Scale bars, 100 μm (B) and 50 μm (C and D).

  • Fig. 2 Ratio of whitlockite to total mineral (apatite + whitlockite) from univariate quantification of the phosphate ν1 peak.

    Average ratios of whitlockite over total mineral within the intima and media. Statistical significance was defined using generalized linear model (GLM) regression followed by analysis of variance (ANOVA); error bars denote 95% confidence intervals. **P < 0.01, n ≥ 9 donors per group.

  • Fig. 3 VCA on Raman spectroscopy images and relevant histology images.

    (A) VCA endmember spectra for nine major components of aortic tissues were found. (B) Representative VCA images, associated histology, and immunofluorescence [red, CD68; green, α–smooth muscle actin (α-SMA); blue, 4′,6-diamidino-2-phenylindole (DAPI)] of aortic tissues from a nonatherosclerotic 65-year-old donor and an atherosclerotic 64-year-old donor (tissue sample taken from the plaque region). Arrows indicate CD68-positive areas. Scale bars, 100 μm. IF, immunofluorescence.

  • Fig. 4 Depth-dependent profiles of the major components in aortic intima and media based on VCA results, normalized to the maximum for each component.

    (A) The relative concentration (Rel.) was summed along the normalized depth of the aorta from the surface of the intima; 0, assigned to the media-adventitia interface; 1, plotted with ±1 SD. (B) Averages of the relative concentrations within the intima and media, normalized to area of the Raman images; error bars denote 95% confidence intervals. Statistical significance was defined using GLM regression followed by ANOVA. CE, cholesterol ester. *P < 0.05, **P < 0.01, n ≥ 9 donors per group. a.u., arbitrary units.

  • Table 1 Experimental groups and donor information.
    Experimental groupsAbbreviationDonorsTissue samplesAge rangeAverage ageMale/female ratio
    Nonatherosclerotic, <50 yearsNAth<50101314–39270.67
    Nonatherosclerotic, >50 yearsNAth>5091254–65581.25
    Atherosclerotic nonplaque, >50 yearsAthnp121557–64570.50
    Atherosclerotic plaque, >50 yearsAthp101357–65570.43

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/3/12/e1701156/DC1

    fig. S1. Comparison of the relative concentrations of apatite and whitlockite between the aortic intima and the media.

    fig. S2. VCA on Raman spectroscopy images and relevant histology images.

    fig. S3. Raman spectra of pure commercial powders.

    fig. S4. Depth-dependent profiles of β-carotene, elastin, collagen, and actin in the aortic intima and media based on VCA results, normalized to the maximum for each component.

    fig. S5. Representative comparison within one donor, for the relative concentrations of major components within the aortic intima and media.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Comparison of the relative concentrations of apatite and whitlockite between the aortic intima and the media.
    • fig. S2. VCA on Raman spectroscopy images and relevant histology images.
    • fig. S3. Raman spectra of pure commercial powders.
    • fig. S4. Depth-dependent profiles of β-carotene, elastin, collagen, and actin in the aortic intima and media based on VCA results, normalized to the maximum for each component.
    • fig. S5. Representative comparison within one donor, for the relative concentrations of major components within the aortic intima and media.

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