Ultrasound inflammation imaging in rats with myocardial ischemia-reperfusion: evaluation by non-specific targeted
Toshihiko Asanuma1, Ryu Mabuchi1, Kasumi Masuda1
1Division of Functional Diagnostics, Department of Health Sciences, Osaka University Graduate School of Medicine, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan.
Background:
Reports on ultrasound inflammation imaging with non-specific targeted microbubbles in the heart have been scarce. We investigated whether inflammation induced by myocardial ischemia-reperfusion in rats could be evaluated by ultrasound inflammation imaging with non-specific targeted microbubbles.
Methods:
Six rats subjected to 30 min of occlusion of the left anterior descending artery (LAD) followed by 4 h of reperfusion (ischemia group) and 4 rats subjected to the sham operation (sham group) were used. Ultrasound inflammation imaging was performed 4 h after reperfusion, and non-circulating signal intensity (SI), which reflects the signal derived from microbubbles phagocytosed by neutrophils in inflamed tissue, was calculated by the SI difference between the initial and subsequent imaging both in the LAD and non-LAD areas. The accumulation of neutrophils was confirmed by myeloperoxidase (MPO) staining.
Results:
Non-circulating SI in the LAD area was significantly greater for the ischemia group than the sham group [5.19 ± 2.19 (ischemia) vs. 0.31 ± 0.13 (sham) dB, p < 0.01]. Non-circulating SI in the LAD area was significantly higher than that in the non-LAD area when compared in the same rat of the ischemia group [5.19 ± 2.19 (LAD) vs. 0.18 ± 0.64 (non-LAD) dB, p < 0.01]. MPO-positive cells were confirmed in the LAD area of the ischemia group.
Conclusion:
Inflammation induced by myocardial ischemia-reperfusion in rats could be quantitatively assessed by ultrasound inflammation imaging with non-specific targeted microbubbles.
Insights
Ultrasound inflammation imaging using non-specific targeted microbubbles can effectively assess heart inflammation after ischemia-reperfusion injury in rats. This method quantifies neutrophil accumulation, aiding in understanding myocardial damage.
Area of Science:
- Cardiovascular Imaging
- Inflammation Imaging
- Ultrasound Technology
Background:
- Limited reports exist on ultrasound inflammation imaging of the heart using non-specific targeted microbubbles.
- Myocardial ischemia-reperfusion injury is a significant cause of heart damage, often accompanied by inflammation.
Purpose of the Study:
- To investigate the efficacy of ultrasound inflammation imaging with non-specific targeted microbubbles in evaluating myocardial ischemia-reperfusion induced inflammation in a rat model.
Main Methods:
- Rats underwent left anterior descending artery occlusion followed by reperfusion (ischemia group) or a sham operation.
- Ultrasound inflammation imaging was performed post-reperfusion to measure non-circulating signal intensity (SI) in ischemic and non-ischemic areas.
- Neutrophil accumulation was confirmed via myeloperoxidase (MPO) staining.
Main Results:
- Significantly higher non-circulating SI was observed in the ischemic (LAD) area of the ischemia group compared to the sham group (p < 0.01).
- Within the ischemia group, the LAD area showed significantly higher non-circulating SI than the non-LAD area (p < 0.01).
- MPO-positive cells confirmed neutrophil presence in the LAD area of the ischemia group.
Conclusions:
- Ultrasound inflammation imaging with non-specific targeted microbubbles provides a quantitative assessment of inflammation following myocardial ischemia-reperfusion in rats.
- This imaging technique shows promise for evaluating inflammatory responses in cardiac injury.
