Background—
Atherosclerosis is considered to be an inflammatory disease associated with the activation of hematopoietic and immune-related organs such as the bone marrow (BM) and spleen. We evaluated the metabolic activity of those organs and of the carotid artery with
18
F-fluorodeoxyglucose positron emission tomography in patients with coronary artery disease, including acute myocardial infarction.
Methods and Results—
Whole-body combined
18
F-fluorodeoxyglucose positron emission tomography/computed tomography was performed in 32 patients with acute myocardial infarction, 33 patients with chronic stable angina, and 25 control subjects. The mean standard uptake value was calculated in the regions of interest in the spleen and the BM of lumbar vertebrae. The target-to-background ratio of the standard uptake values of the carotid artery and jugular vein was also calculated. In patients with acute myocardial infarction, the standard uptake values of the BM (1.67±0.16) and spleen (2.57±0.39), as well as the target-to-background ratio of the carotid artery (2.13±0.42), were significantly higher than the corresponding values of patients with angina (1.22±0.62; 2.03±0.35; 1.36±0.37; all
P
<0.001) and controls (0.80±0.44; 1.54±0.26; 1.22±0.22; all
P
<0.001), independent of traditional cardiovascular risk factors and high-sensitivity C-reactive protein. In all groups combined, the target-to-background ratio of the carotid artery was significantly associated with the standard uptake values of the BM (
r
=0.535;
P
<0.001), spleen (
r
=0.663;
P
<0.001), and high-sensitivity C-reactive protein (
r
=0.465;
P
<0.001).
Conclusions—
The metabolic activity of the BM and spleen, as well as of the carotid artery, was highest in patients with acute myocardial infarction, intermediate in patients with angina, and lowest in control subjects. The activation of the BM and spleen was significantly associated with inflammatory activity of the carotid artery.
BackgroundDuring myocardial ischemia/reperfusion (I/R), a large amount of reactive oxygen species (ROS) is produced. In particular, overproduction of hydrogen peroxide (H2O2) is considered to be a main cause of I/R‐mediated tissue damage. We generated novel H2O2‐responsive antioxidant polymer nanoparticles (PVAX and HPOX) that are able to target the site of ROS overproduction and attenuate the oxidative stress‐associated diseases. In this study, nanoparticles were examined for their therapeutic effect on myocardial I/R injury.Methods and ResultsThe therapeutic effect of nanoparticles during cardiac I/R was evaluated in mice. A single dose of PVAX (3 mg/kg) showed a significant improvement in both cardiac output and fraction shortening compared with poly(lactic‐coglycolic acid) (PLGA) particle, a non‐H2O2‐activatable nanoparticle. PVAX also significantly reduced the myocardial infarction/area compared with PLGA (48.7±4.2 vs 14.5±2.1). In addition, PVAX effectively reduced caspase‐3 activation and TUNEL‐positive cells compared with PLGA. Furthermore, PVAX significantly decreased TNF‐α and MCP‐1 mRNA levels. To explore the antioxidant effect of PVAX by scavenging ROS, dihydroethidium staining was used as an indicator of ROS generation. PVAX effectively suppressed the generation of ROS caused by I/R, whereas a number of dihydroethidium‐positive cells were observed in a group with PLGA I/R. In addition, PVAX significantly reduced the level of NADPH oxidase (NOX) 2 and 4 expression, which favors the reduction in ROS generation after I/R.ConclusionsTaken together, these results suggest that H2O2‐responsive antioxidant PVAX has tremendous potential as a therapeutic agent for myocardial I/R injury.
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