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Arterioscler Thromb Vasc Biol. 2010 Oct;30(10):1933-9. doi: 10.1161/ATVBAHA.110.206342. Epub 2010 Aug 5.

Pioglitazone suppresses inflammation in vivo in murine carotid atherosclerosis: novel detection by dual-target fluorescence molecular imaging.

Author information

1
Cardiovascular Research Center and the Cardiology Division, Massachusetts General Hospital, Boston, Mass 02114, USA.

Abstract

OBJECTIVE:

To investigate the effects of pioglitazone (PIO), a peroxisome proliferator-activated receptor γ agonist, on plaque matrix metalloproteinase (MMP) and macrophage (Mac) responses in vivo in a molecular imaging study.

METHODS AND RESULTS:

In vitro, PIO suppressed MMP-9 protein expression in murine peritoneal Macs (P<0.05). To assess PIO's effects on plaque inflammation, nondiabetic apolipoprotein E(-/-) mice receiving a high-cholesterol diet (HCD) were administered an MMP-activatable fluorescence imaging agent and a spectrally distinct Mac-avid fluorescent nanoparticle. After 24 hours, mice underwent survival dual-target intravital fluorescence microscopy of carotid arterial plaques. These mice were then randomized to HCD or HCD plus 0.012% PIO for 8 weeks, followed by a second intravital fluorescence microscopy study of the same carotid plaque. In the HCD group, in vivo MMP and Mac target-to-background ratios increased similarly (P<0.01 versus baseline). In contrast, PIO reduced MMP and Mac target-to-background ratios (P<0.01) versus HCD. Changes in MMP and Mac signals correlated strongly (r ≥0.75). Microscopy demonstrated MMP and Mac reductions in PIO-treated mice and a PIO-modulated increase in plaque collagen.

CONCLUSIONS:

Serial optical molecular imaging demonstrates that plaque MMP and Mac activity in vivo intensify with hypercholesterolemia and are reduced by PIO therapy.

PMID:
20689078
PMCID:
PMC3030475
DOI:
10.1161/ATVBAHA.110.206342
[Indexed for MEDLINE]
Free PMC Article

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