Magnetic resonance of coronary arteries: assessment of luminal narrowing and blood flow in the coronary arteries

Magnetic resonance/fluorescence dual-modality contrast agents targeting αvβ6-overexpressing tumors based on A20FMDV2 peptide as a ligand

Pancreatic ductal adenocarcinoma (PDAC) is a malignant digestive system tumor with a poor late-stage prognosis. This study aimed to identify new methods for the early detection of PDAC. The nanoprobe A20FMDV2-Gd-5-FAM was developed using A20FMDV2 (N¹AVPNLRGDLQVLAQKVART²⁰-NH₂, A20FMDV2) as the ligand and characterized using dynamic light scattering, transmission electron microscopy, Fourier transform infrared analysis, and UV absorption spectroscopy. The binding of pancreatic cancer cells AsPC-1, MIA PaCa-2, and normal human pancreatic H6C7 cells (HPDE6-C7) to the probe was verified using laser confocal microscopy, and the biocompatibility of the probe was evaluated in vivo. In vivo magnetic resonance and fluorescence imaging were also performed on nude mice with subcutaneous pancreatic tumor xenografts to verify the bimodal imaging performance of the probe. The probe exhibited good stability and biocompatibility and an enhanced relaxation rate (25.46 ± 1.32 mM^-1 s^-1) than Gd-DTPA. Confocal laser scanning microscopy results revealed that the A20FMDV2-Gd-5-FAM probe could be successfully ingested and internalized, and infrared analysis results demonstrated that the probe was linked successfully. Finally, magnetic resonance T₁WI imaging and intravital fluorescence imaging demonstrated the specific signal enhancement of the probe at the tumor site. In conclusion, the bimodal molecular probe A20FMDV2-Gd-5-FAM showed a stable magnetic resonance and fluorescence bimodal imaging performance and is a promising new approach for diagnosing early-stage cancers with a high integrin α_vβ₆ expression.

Circular RNA circ_0001445 alleviates the ox-LDL-induced endothelial injury in human primary aortic endothelial cells through regulating ABCG1 via acting as a sponge of miR-208b-5p

BACKGROUND

Coronary artery disease (CAD) originates from the blockage of the inner walls of the coronary arteries due to a plaque buildup. Circular RNA (circRNA) circ_0001445 has been reported to be downregulated in patients with a higher coronary atherosclerotic burden. This study is designed to explore the role and mechanism of circ_0001445 on the oxidized low-density lipoprotein (ox-LDL)-induced endothelial cell damage.

METHODS

Circ_0001445, microRNA-208b-5p (miR-208b-5p), and ATP-binding cassette sub-family G member 1 (ABCG1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Inflammatory cytokines levels, cell viability, proliferation, migration were detected by Enzyme-linked immunosorbent assay (ELISA) kits, Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and transwell assays, respectively. Protein levels were determined by western blot assay. The binding between miR-208b-5p and circ_0001445 or ABCG1 was predicted by circBank or TargetScan, and then verified by a dual-luciferase reporter, RNA Immunoprecipitation (RIP), and RNA pull-down assays.

RESULTS

Circ_0001445 and ABCG1 were decreased, and miR-208b-5p was increased in CAD patients and ox-LDL-treated HAECs. Also, circ_0001445 overexpression could weaken ox-LDL-triggered HAEC injury by boosting proliferation, migration, and repressing inflammation and extracellular matrix (ECM). Mechanically, circ_0001445 directly targeted miR-208b-5p. Furthermore, miR-208b-5p mediated the modulation of circ_0001445 in ox-LDL-induced HAEC injury. ABCG1 acted as a direct target of miR-208b-5p, and the downregulation of miR-208b-5p relieved ox-LDL-induced HAEC damage by interacting with ABCG1. Additionally, circ_0001445 regulated ABCG1 expression by sponging miR-208b-5p.

CONCLUSION

Circ_0001445 could abate ox-LDL-mediated HAEC damage by the miR-208b-5p/ABCG1 axis, providing a novel insight into the pathogenesis and treatment of CAD.

Diagnostic Accuracy of Three-Dimensional Whole-Heart Magnetic Resonance Angiography to Detect Coronary Artery Disease with Invasive Coronary Angiography as a Reference: A Meta-Analysis

Objective: We aimed to evaluate the diagnostic performance of three-dimensional whole-heart magnetic resonance coronary angiography (MRCA) in detecting coronary artery disease (CAD) with invasive coronary angiography as the reference standard.Methods: We searched PubMed and Embase for studies evaluating the diagnostic performance of three-dimensional whole-heart MRCA for the diagnosis of CAD with invasive coronary angiography as the reference standard. The bivariate mixed-effects regression model was applied to synthesize available data. The clinical utility of whole-heart MRCA was calculated by the posttest probability based on Bayes’s theorem.Results: Eighteen studies were included, of which 16 provided data at the artery level. Patient-based analysis revealed a pooled sensitivity of 0.90 (95% confidence interval [CI] 0.87‐0.93) and specificity of 0.79 (95% CI 0.73‐0.84), while the pooled estimates were 0.86 (95% CI 0.82‐0.89) and 0.89 (95% CI 0.84‐0.92), respectively, at the artery level. The areas under the summary receiver operating characteristic curve were 0.93 (95% CI 0.90‐0.95) and 0.92 (95% CI 0.90‐0.94) at the patient and artery levels, respectively. With a pretest probability of 50%, the patients’ posttest probabilities of CAD were 81% for positive results and 11% for negative results.Conclusions: Whole-heart MRCA can be an alternative noninvasive method for diagnosis and assessment of CAD.

Effect of Korean Magnolia obovata Extract on Platelet-Derived Growth Factor-Induced Vascular Smooth Muscle Cells

OBJECTIVE

To investigate the effects of Korean Magnolia obovata crude extract (KME) on plateletderived growth factor (PDGF)-BB-induced proliferation and migration of vascular smooth muscle cells (VSMCs).

METHODS

KME composition was analyzed by high-performance liquid chromatography (HPLC). VSMCs were isolated from the aorta of a Sprague-Dawley rat, incubated in serum free-Dulbecco's modified Eagle's medium in the presence or absence of KME (10, 30, 100, and 300 μg/mL), then further treated with PDGF-BB (10 ng/mL). VSMC proliferation was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and VSMC migration was determined using the Boyden chamber and scratch wound healing assays. Western blot analysis was used to detect phosphorylation of extracellular signal-regulated protein kinases 1 and 2 (p-ERK1/2), protein kinase B (p-Akt), and stress-activated protein kinase/c-Jun NH2-terminal kinase (p-SAPK/JNK). The antimigration and proliferation effects of KME were tested using aortic sprout outgrowth.

RESULTS

The HPLC analysis identified honokiol (0.45 mg/g) and magnolol (0.34 mg/g) as the major components of KME. KME (30, 100, and 300 μg/mL) significantly decreased the proliferation and migration of PDGF-BB-stimulated (10 ng/mL) VSMCs and the PDGF-BB-induced phosphorylation of EKR1/2, Akt, and SAPK/JNK (P<0.05). Furthermore, PDGF-BBinduced VSMCs treated with 300 μg/mL of KME showed reduction in aortic sprout outgrowth.

CONCLUSION

KME could inhibit abnormal proliferation and migration of VSMCs by down-regulating the phosphorylation of EKR1/2 and Akt. Thus, KME might be a functional food for preventing vascular disorders.

Labeling monocytes with gold nanoparticles to track their recruitment in atherosclerosis with computed tomography

Monocytes are actively recruited from the circulation into developing atherosclerotic plaques. In the plaque, monocytes differentiate into macrophages and eventually form foam cells. Continued accumulation of foam cells can lead to plaque rupture and subsequent myocardial infarction. X-ray computed tomography (CT) is the best modality to image the coronary arteries non-invasively, therefore we have sought to track the accumulation of monocytes into atherosclerotic plaques using CT. Gold nanoparticles were synthesized and stabilized with a variety of ligands. Select formulations were incubated with an immortalized monocyte cell line in vitro and evaluated for cytotoxicity, effects on cytokine release, and cell uptake. These data identified a lead formulation, 11-MUDA capped gold nanoparticles, to test for labeling primary monocytes. The formulation did not the affect the viability or cytokine release of primary monocytes and was highly taken up by these cells. Gold labeled primary monocytes were injected into apolipoprotein E deficient mice kept on Western diet for 10 weeks. Imaging was done with a microCT scanner. A significant increase in attenuation was measured in the aorta of mice receiving the gold labeled cells as compared to control animals. Following the experiment, the biodistribution of gold was evaluated in major organs. Additionally, plaques were sectioned and examined with electron microscopy. The results showed that gold nanoparticles were present inside monocytes located within plaques. This study demonstrates the feasibility of using gold nanoparticles as effective cell labeling contrast agents for non-invasive imaging of monocyte accumulation within plaques with CT.

Validation of high temporal resolution spiral phase velocity mapping of temporal patterns of left and right coronary artery blood flow against Doppler guidewire

BACKGROUND

Temporal patterns of coronary blood flow velocity can provide important information on disease state and are currently assessed invasively using a Doppler guidewire. A non-invasive alternative would be beneficial as it would allow study of a wider patient population and serial scanning.

METHODS

A retrospectively-gated breath-hold spiral phase velocity mapping sequence (TR 19 ms) was developed at 3 Tesla. Velocity maps were acquired in 8 proximal right and 15 proximal left coronary arteries of 18 subjects who had previously had a Doppler guidewire study at the time of coronary angiography. Cardiovascular magnetic resonance (CMR) velocity-time curves were processed semi-automatically and compared with corresponding invasive Doppler data.

RESULTS

When corrected for differences in heart rate between the two studies, CMR mean velocity through the cardiac cycle, peak systolic velocity (PSV) and peak diastolic velocity (PDV) were approximately 40 % of the peak Doppler values with a moderate - good linear relationship between the two techniques (R(2): 0.57, 0.64 and 0.79 respectively). CMR values of PDV/PSV showed a strong linear relationship with Doppler values with a slope close to unity (0.89 and 0.90 for right and left arteries respectively). In individual vessels, plots of CMR velocities at all cardiac phases against corresponding Doppler velocities showed a consistent linear relationship between the two with high R(2) values (mean +/-SD: 0.79 +/-.13).

CONCLUSIONS

High temporal resolution breath-hold spiral phase velocity mapping underestimates absolute values of coronary flow velocity but allows accurate assessment of the temporal patterns of blood flow.

MR imaging of the coronary vasculature: imaging the lumen, wall, and beyond

The characteristics of coronary artery disease are gradual thickening of the coronary walls and narrowing of the vascular lumen by the buildup of atherosclerosis plaques. These morphologic changes can be noninvasively detected by coronary magnetic resonance (MR) imaging/MR angiography (MRA). In addition, functional changes, such as coronary wall distensibility and flow changes, may also be evaluated with MR imaging. However, the application of current MR imaging/MRA techniques is limited in clinical practice because of several adverse technical and physiologic factors, such as cardiac and respiratory motion. Many technical innovations have been adopted to address these problems from multiple aspects.