Fine particulate matter air pollution and aortic perivascular adipose tissue: Oxidative stress, leptin, and vascular dysfunction

Figures

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  FIGURE 1. Murine thoracic aortic perivascular adipose tissue (PVAT) structure and function. a) Isolated thoracic aorta with PVAT intact (accompanying dashed lines indicate the approximate location of a 3‐mm segment to be used for functional assay). b) Image of a hematoxylin‐eosin stained cross‐section of the formalin‐fixed aorta with PVAT intact (40x magnification). Inset: Enhanced view of the interface between aortic wall adventitia and PVAT (400x magnification). c) Summary data of cumulative concentration‐dependent phenylephrine‐ (PE) induced increase in isometric tension (mN/mm3) of isolated aortic rings with and without PVAT. d) Summary data of the endogenous anti‐contractile effect of PVAT in aortas stimulated with PE (100 nM). Data are mean ± SE. n = 3. * p < 0.05 versus matched clean aorta

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  FIGURE 2. CAP‐induced PVAT oxidative stress and insulin resistance. Western blots and densitometric analyses of protein–acrolein adduct abundance in PVAT (a) and aorta (c) of mice exposed for 9 days to either air or CAP. Inset: Membranes stained with amido black served as loading controls. Data are mean ± SE normalized to air controls (n = 4, * p < 0.05 vs. air group). Insulin‐stimulated (+I, 100 nM, 15 min) Akt phosphorylation in isolated PVAT (b) and aorta (d) of mice exposed for 9 days to either air or CAP. Data are mean ± SE normalized to controls (n = 4; * p < 0.05 insulin vs. control; # p < 0.05 air vs. CAP)

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  FIGURE 3. Gene expression and function of aortic PVAT. a) Relative abundance of inflammatory and adipose‐related mRNAs measured by qRT‐PCR analysis in PVAT isolated from WT mice exposed to either air or CAP for 9 days. b) Effect of the leptin receptor antagonist (SLAN) on aorta contractile response to PE and thromboxane A2 analog, U46,619. c) Effect of SLAN on aortic relaxation of ACh and SNP in PE‐precontracted aorta. d) Effect of PVAT anti‐contractile activity against 100 mM HI K+‐induced tension. e) PE‐induced tension (10 μM) in the clean aorta, aorta with intact PVAT, and clean aorta with isolated PVAT immersed in organ bath. Data are mean ± SE. * p < 0.05 versus air group (n = 4–8) or matched clean aorta (n = 3); #0.10 > p > 0.05 versus matched clean aorta (n = 3)

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  FIGURE 4. CAP‐induced effects on aorta and PVAT function. a) Representative images of aortic cross‐sections stained with Sirius Red/Fast Green (lamellae/collagen fibers and adventitia in red; PVAT and smooth muscle in green) of air‐ (Ai) and CAP‐ (Aii) exposed mice. b–d) Summary effects of 9‐day air and CAP exposures on responses of isolated aorta with and without PVAT to phenylephrine (efficacy and sensitivity) in (b, c) summer or (d) winter. (e) Summary data of “PE Contraction Ratio” (tensionPE+L‐NAME/tensionPE alone) of isolated aorta after 9‐day air and CAP exposures in winter. Data are mean ± SE. n = 4–8. * p < 0.05 versus matched clean aorta; #0.10 > p > 0.05 versus matched air control

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  FIGURE 5. Prevention of CAP‐induced effects in ecSOD‐Tg mice. a) Levels of thiobarbituric acid reactive substances (TBARS) measured in the lungs of ecSOD‐Tg mice and their WT littermates inhaling air or CAP for 9 days. b) Urinary levels of the acrolein metabolite 3‐hydroxypropylmercapturic acid (3HPMA) in WT and ecSOT‐Tg mice exposed for 6 h to air or CAP. c) Relative abundance of inflammatory and adipose‐related mRNAs measured by qRT‐PCR in PVAT isolated from ecSOD‐Tg mice inhaling either air or CAP. The qRT‐PCR data are normalized to the data obtained from the WT‐air controls of the same exposure experiments that are shown in Figure 3a. Data are mean ± SE (n = 3–9; *p < 0.05 vs. matched air control). d–e). CAP exposure had no effect on anti‐contractile function of PVAT to single concentration (100 nM; d) or cumulative PE (1–1,000 nM; e) in ecSOD‐Tg mice. Data are mean ± SE (n = 4–8; *p < 0.05 vs. matched clean aorta)