Perivascular Adipose Tissue Inflammation in Ischemic Heart Disease.

OBJECTIVE: There is growing recognition that adipose tissue-derived proatherogenic mediators contribute to obesity-related cardiovascular disease. We sought to characterize regional differences in perivascular adipose tissue (PVAT) phenotype in relation to atherosclerosis susceptibility. Approach and Results: We examined thoracic PVAT samples in 34 subjects (body mass index 32±6 kg/m2, age 59±11 years) undergoing valvular, aortic, or coronary artery bypass graft surgeries and performed transcriptomic characterization using whole-genome expression profiling and quantitative polymerase chain reaction analyses. We identified a highly inflamed region of PVAT surrounding the human aortic root in close proximity to coronary takeoff and adjoining epicardial fat. In subjects undergoing coronary artery bypass graft, we found 300 genes significantly upregulated (false discovery rate Q<0.1) in paired samples of PVAT surrounding the aortic root compared with nonatherosclerotic left internal mammary artery. Genes encoding proteins mechanistically implicated in atherogenesis were enriched in aortic PVAT consisting of signaling pathways linked to inflammation, WNT (wingless-related integration site) signaling, matrix remodeling, coagulation, and angiogenesis. Overexpression of several proatherogenic transcripts, including IL1ß, CCL2 (MCP-1), and IL6, were confirmed by quantitative polymerase chain reaction and significantly bolstered in coronary artery disease subjects. Angiographic coronary artery disease burden quantified by the Gensini score positively correlated with the expression of inflammatory genes in PVAT. Moreover, periaortic adipose inflammation was markedly higher in obese subjects with striking upregulation (≈8-fold) of IL1ß expression compared to nonobese individuals. CONCLUSIONS: Proatherogenic mediators that originate from dysfunctional PVAT may contribute to vascular disease mechanisms in human vessels. Moreover, PVAT may adopt detrimental properties under obese conditions that play a key role in the pathophysiology of ischemic heart disease. Graphic Abstract: A graphic abstract is available for this article.

Reperfusion and Time to Presentation in Women: Too Little Too Late.

See Editorial by Cenko et al.

Comparison of symptoms, treatment, and outcomes of coronary artery disease among rheumatoid arthritis and matched subjects undergoing percutaneous coronary intervention.

OBJECTIVE: Rheumatoid arthritis (RA) is associated with an increased prevalence of coronary artery disease (CAD). We investigated the presenting symptoms of CAD, coronary anatomy (single versus multi-vessel CAD), and treatment among a group of subjects undergoing percutaneous coronary intervention (PCI) with angioplasty and/or stenting. METHODS: We evaluated a retrospective cohort of 43 RA subjects and 43 matched non-RA subjects undergoing PCI at 2 academic referral centers. RA subjects were matched to non-RA subjects on age, gender, history of coronary artery bypass grafting, date of PCI, and interventional cardiologist. We compared cardiac risk factors, presentation, treatment, and outcomes. RESULTS: The mean age of the study cohort was 71 ± 10 years, and the distribution of traditional cardiac risk factors was similar in the subjects with RA compared with the matched non-RA subjects (all P values > 0.05). Seventy-four percent of subjects with RA compared with 67% of those without RA presented with an acute coronary syndrome before PCI (P = 0.48). All subjects in this cohort undergoing PCI had at least 1 stenosis in a major epicardial vessel and similar percentages of subjects with RA (44%) and without RA (40%) had multi-vessel CAD (P = 0.66). The administration of cardiac medications both at PCI and at hospital discharge was not different among subjects with RA compared with matched non-RA subjects. CONCLUSIONS: Among this cohort with significant CAD undergoing PCI, clinical characteristics, presentation, severity of CAD, treatment modalities, and outcomes were similar in subjects with RA and well-matched non-RA subjects.

Optical visualization of cathepsin K activity in atherosclerosis with a novel, protease-activatable fluorescence sensor.

BACKGROUND: Cathepsin K (CatK), a potent elastinolytic and collagenolytic cysteine protease, likely participates in the evolution and destabilization of atherosclerotic plaques. To assess better the biology of CatK activity in vivo, we developed a novel near-infrared fluorescence (NIRF) probe for imaging of CatK and evaluated it in mouse and human atherosclerosis. METHODS AND RESULTS: The NIRF imaging agent consists of the CatK peptide substrate GHPGGPQGKC-NH2 linked to an activatable fluorogenic polymer. In vitro, CatK produced a 2- to 14-fold activation of the agent over other cysteine and matrix metalloproteinases (P<0.0001), as well as a >8-fold activation over a control imaging agent (P<0.001). Optical imaging of atheroma revealed >100% NIRF signal increases in apolipoprotein E-/- mice in vivo (n=13; P<0.05, CatK imaging agent versus control agent) and in human carotid endarterectomy specimens ex vivo (n=14; P<0.05). Fluorescence microscopy of plaque sections demonstrated that enzymatically active CatK (positive NIRF signal) localized primarily in the vicinity of CatK-positive macrophages. Augmented NIRF signal (reflecting CatK activity) colocalized with disrupted elastin fibers within the media underlying plaques. CONCLUSIONS: Use of this novel protease-activatable NIRF agent for optical imaging in vivo demonstrated preferential localization of enzymatically active CatK to macrophages, consistent with their known greater elastinolytic capabilities compared with smooth muscle cells. Augmented CatK proteolysis in atheromata further links CatK to vascular remodeling and plaque vulnerability.

Dual channel optical tomographic imaging of leukocyte recruitment and protease activity in the healing myocardial infarct.

Inflammatory responses after myocardial infarction profoundly impact tissue repair. Yet, efficient tools to serially and noninvasively assess cellular and molecular functions in postinfarct inflammation are lacking. Here we use multichannel fluorescent molecular tomography (FMT) for spatiotemporal resolution of phagocytic and proteolytic activities mediated by macrophages and neutrophils in murine infarcts. We performed FMT imaging to compare the course of efficient and impaired healing in wild-type and FXIII-/- mice, respectively. Mice subjected to coronary ligation received simultaneous injections with Prosense-680, an activatable fluorescence sensor reporting on cathepsin activity, and CLIO-VT750, a magneto-fluorescent nanoparticle for imaging of phagocyte recruitment. On FMT, Prosense-680 infarct signal was 19-fold higher than background (P<0.05). Protease activity was higher in the infarcted lateral wall than in the remote, uninjured septum on ex vivo fluorescence reflectance imaging (contrast to noise ratio 118+/-24). CLIO-VT750 FMT signal coregistered with contrast enhancement in the hypokinetic infarct on MRI. Microscopic fluorescence signal colocalized with immunoreactive staining for cathepsin, macrophages and neutrophils. Flow cytometry of digested infarcts revealed monocytes/macrophages and neutrophils as the source of the fluorescence signal. Phagocytic activity peaked on day 6, and proteolytic activity peaked on day 4 after myocardial infarction. FMT detected impaired recruitment of phagocytes and protease activity in FXIII-/- mice (P<0.05). FMT is a promising noninvasive molecular imaging approach to characterize infarct healing. Spectrally resolved imaging agents allow for simultaneous assesment of key processes of in vivo cellular functions. Specifically, we show that in vivo FMT detects impaired healing in FXIII-/- mice.

Detection of macrophage activity in atherosclerosis in vivo using multichannel, high-resolution laser scanning fluorescence microscopy.

Molecular and cellular mechanisms of atherogenesis and its treatment are largely being unraveled by in vitro techniques. We describe methodology to directly image macrophage cell activity in vivo in a murine model of atherosclerosis using laser scanning fluorescence microscopy (LSFM) and a macrophage-targeted, near-infrared fluorescent (NIRF) magnetofluorescent nanoparticle (MFNP). Atherosclerotic apolipoprotein E deficient (apoE -/-) mice (n=10) are injected with MFNP or 0.9% saline, and wild-type mice (n=4) are injected with MFNP as additional controls. After 24 h, common carotid arteries are surgically exposed and prepared for LSFM. Multichannel LSFM of MFNP-enhanced carotid atheroma (5x5-microm in-plane resolution) shows a strong focal NIRF signal, with a plaque target-to-background ratio of 3.9+/-1.8. Minimal NIRF signal is observed in control mice. Spectrally resolved indocyanine green (ICG) fluorescence angiograms confirm the intravascular location of atheroma. On ex vivo fluorescence reflectance imaging, greater NIRF plaque signal is seen in apoE -/- MFNP mice compared to controls (p<0.01). The NIRF signal correlates well with immunostained macrophages, both by stained surface area (r=0.77) and macrophage number (r=0.86). The validated experimental methodology thus establishes a platform for investigating macrophage activity in atherosclerosis in vivo, and has implications for the detection of clinical vulnerable plaques.