Early Assessment of Atherosclerotic Lesions and Vulnerable Plaques in vivo by Targeting Apoptotic Macrophages with AV Nanobubbles.

Background: The early detection of atherosclerotic lesions is particularly important for risk prediction of acute cardiovascular events. Macrophages apoptosis was significantly associated with the degree of AS lesions and especially contributed to plaque vulnerability. In this research, we mainly sought to explore the feasibility of a home-made AV-nanobubbles (NBAV) for visualization of apoptotic macrophages and assessment of atherosclerosis (AS) lesions by contrast-enhanced ultrasound (CEUS) imaging. Methods: NBAV were prepared by "Optimized Thin-Film Hydration" and "Biotin-Avidin-Biotin" methods. Then, the characterization and echogenicity of NBAV were measured and analyzed in vitro. The targeting ability of NBAV to ox-LDL-induced apoptotic macrophages was observed by laser scanning confocal microscope. The ApoE-/- mice mode fed with high fat diet were observed by high-frequency ultrasound, microanatomy and oil red O staining. CEUS imaging in vivo was performed on AS plaques with NBAV and NBCtrl injection through the tail vein in turn in ApoE-/- mice. After CEUS imaging, the plaques were confirmed and analyzed by histopathological and immunological assessment. Results: The prepared NBAV had a nano-scale size distribution with a low PDI and a negative zeta potential. Moreover, NBAV showed an excellent stability and exhibited a significantly echogenic signal than saline in vitro. In addition, we found that NBAV could target apoptotic macrophages induced by ox-LDL. Compared with NBCtrl, CEUS imaging of NBAV showed strong and sustained echo enhancement in plaque area of aortic arch in vivo. Further research showed that NBAV sensitive plaques presented more significant pathological changes with several vulnerable plaque features and abundant TUNEL-positive area. Conclusion: NBAV displayed a sensitive indicator to evaluate apoptotic macrophages, indicating a promising CEUS molecular probe for AS lesions and vulnerable plaques identification.

The severity of portal hypertension by a non-invasive assessment: acoustic structure quantification analysis of liver parenchyma.

BACKGROUND: Acoustic structure quantification (ASQ) has been applied to evaluate liver histologic changes by analyzing the speckle pattern seen on B-mode ultrasound. We aimed to assess the severity of portal hypertension (PHT) through hepatic ultrasonography. METHODS: Sixty patients diagnosed with PHT and underwent surgical treatment with portosystemic shunts were enrolled. Portal pressure (PP) was measured intraoperatively. Patients were divided into subgroups according to the severity of gastroesophageal varices and Child-Pugh class. Three difference ratio (Cm2) values on ASQ histogram mode were analyzed for their relationships with PP, degree of gastroesophageal varices and Child-Pugh liver function. Thirty healthy volunteers matched with the patients for gender and age were enrolled as controls. Comparisons among groups and correlation of the parameters with PP were analyzed. Area under the receive operating characteristic curve was used to evaluate the predicting value of ASQ parameters. RESULTS: In the patients, the ASQ parameters peak Cm2 (Cm2max), mean Cm2 (Cm2mean) and the highest occurred Cm2 value of the obtained red curve (RmaxCm2) were all greatly increased (P < 0.0001, P < 0.0001, P = 0.027). Multiple comparisons indicated that, regardless of Child-Pugh class and degree of gastroesophageal varices, the patients had significantly increased Cm2max and Cm2mean compared with the controls (all P < 0.0001). No differences among subgroups were observed. Cm2max was significantly statistically correlated with PP (r = 0.3505, P < 0.01), degree of varices (r = 0.4998, P < 0.0001). Youden's index for Cm2max with a cut-off value of 140.3 for predicting the presence of PHT, gastroesophageal varices and liver function equal to or worse than Child-Pugh class B were 0.8, 0.91 and 0.84, respectively. CONCLUSIONS: ASQ analysis of ultrasonographic images may have a role in the evaluation of the severity of PHT by detecting liver histologic changes in the speckle pattern caused by cirrhosis.

Ultrasonic assessment of liver stiffness and carotid artery elasticity in patients with chronic viral hepatitis.

BACKGROUND: This study investigated the relationship between liver stiffness and carotid artery elasticity in patients with chronic viral hepatitis. We used an acoustic radiation force impulse (ARFI) technique to measure stiffness, and a radio frequency (RF) vascular quantitative ultrasound technique to measure changes in common carotid artery elasticity and vascular function. METHODS: Two-hundred seventeen patients with chronic viral hepatitis caused by either hepatitis B virus (HBV) or hepatitis C virus (HCV) were enrolled. We divided the patients into two groups, one comprising 147 patients with chronic hepatitis B (CHB) (98 men and 49 women, average age 46.5 ± 12.2 years) and another comprising 70 patients with chronic hepatitis C (CHC) (47 men and 23 women, average age 47.6 ± 12.1 years). Additionally, 64 healthy age- and sex-matched participants (43 men and 21 women, average age 47.8 ± 5.1 years) were selected as the control group. The ARFI technique was used to measure liver stiffness and the RF ultrasound technique was used to measure carotid artery elasticity parameters including intima-media thickness (IMT), pulse wave velocity (PWV), arterial wall dilation coefficient (DC), compliance coefficient (CC), sclerosis indices α and ß, and augmentation index (Aix). Clinical indicators, liver stiffness, and carotid artery elasticity parameters were observed and compared between the different age groups to investigate the correlation between carotid artery elasticity parameters and liver stiffness. RESULTS: The ARFI values for the CHB and CHC groups were significantly higher than those for the control group (1.84 ± 0.52 vs. 1.04 ± 0.11 m/s; 1.86 ± 0.37 vs. 1.04 ± 0.11 m/s, respectively; P < 0.001). When compared to the control group, both CHB and CHC groups showed an IMT of the same order, but had significantly higher elasticity parameters, such as α and ß, as well as lower DC and CC values (P < 0.001). The PWV of the CHC group was significantly higher than that of the control group (7.98 ± 1.42 vs. 6.09 ± 0.90 m/s, P < 0.001). In the CHB group, all parameters including ARFI, IMT, PWV, DC, CC, α and ß, were significantly different between the two age groups (P < 0.05). Within the CHC group, all parameters including IMT, PWV, DC, α and ß, were significantly different between the two age groups (P < 0.05), except for ARFI, wherein the difference was not statistically significant. The correlation analysis and stepwise multiple linear regression analysis indicated that for patients with CHB, age was an independent predictor of common carotid artery IMT (R2 = 0.468, F = 54.635, and P < 0.001). For patients with CHC, age and blood sugar were independent predictors of common carotid artery IMT (R2 = 0.465, F = 29.118, and P < 0.001). CONCLUSION: Although based on ARFI and RF ultrasound, the carotid artery IMT in patients with CHB and CHC was not significantly higher than that in the control group, their functional elasticity parameters had already changed. This finding serves as a useful reference for the clinical diagnosis of vascular diseases in patients with viral hepatitis. TRIAL REGISTRATION: ClinicalTrials: ChiCTR1800015859 25/04/2018.

Annexin V conjugated nanobubbles: A novel ultrasound contrast agent for in vivo assessment of the apoptotic response in cancer therapy.

In vivo assessment of apoptotic response to cancer therapy is believed to be very important for optimizing management of treatment. However, few noninvasive strategies are currently available to monitor the therapeutic response in vivo. Ultrasonography has been used to detect apoptotic cell death in vivo, but a high-frequency transducer is needed. Fortunately, the capability of ultrasound contrast agents (UCAs) to exit the leaky vasculature of tumors enables ultrasound-targeted imaging of molecular events in response to cancer therapy. In this study, we prepared a novel nano-sized UCA, namely, Annexin V-conjugated nanobubbles (AV-NBs, 635.5 ±â€¯25.4 nm). In vitro studies revealed that AV-NBs were relatively stable and highly echogenic. Moreover, these AV-NBs could easily extravasate into the tumor vasculature and recognize the apoptotic cells with high specificity and affinity in tumors sensitive to chemotherapy. Ultrasound imaging results demonstrated that AV-NBs had higher echogenicity and significantly greater enhancement compared with the untargeted control NBs (P < 0.01) inside the tumors after chemotherapy. Taken together, this study provides a promising method to accurately evaluate therapeutic effects at the molecular level to support cancer management.

Assessment of intrahepatic blood flow by Doppler ultrasonography: relationship between the hepatic vein, portal vein, hepatic artery and portal pressure measured intraoperatively in patients with portal hypertension.

BACKGROUND: Abnormality of hepatic vein (HV) waveforms evaluated by Doppler ultrasonography has been widely studied in patients with chronic liver disease. We investigated the correlation between changes in HV waveforms and portal vein velocity (PVVel), the hepatic artery pulsatility index (HAPI), and also the extent of abnormal Doppler HV waveforms expressed as damping index (DI), severity of portal hypertension expressed as Child-Pugh scores and portal pressure (PP) measured directly from patients with portal hypertension (PHT) to evaluate the indicative value of abnormal HV waveforms and discuss the cause of abnormal HV waveform. METHODS: Sixty patients who had been diagnosed with PHT and accepted surgical therapy of portosystemic shunts were investigated. PP was measured intraoperatively. Thirty healthy volunteers with no history of chronic liver disease were enrolled as the control group. HV waveforms were categorized as triphasic, biphasic or monophasic. DI was compared as the quantitative indicator of abnormal HV waveforms. Another two Doppler parameters, PVVel and HAPI were also measured. These Doppler features were compared with PP, Child-Pugh scores and histological changes assessed by liver biopsy. RESULTS: In the patient group, the Doppler flow waveforms in the middle HV were triphasic in 31.6%, biphasic in 46.7%, and monophasic in 21.6% of subjects. These figures were 86.7%, 10.0%, and 3.3%, respectively, in healthy subjects. With the flattening of HV waveforms, the HAPI increased significantly (r = 00.438, p < 0.0001), whereas PVVel decreased significantly (r = -0.44, p <0.0001). Blood flow parameters, HAPI, PVVel and HV-waveform changes showed no significant correlations with Child-Pugh scores. The latter showed a significant correlation with PP (r = 0.589, p = 0.044). Changes of HV waveform and DI significantly correlated with PP (r = 0.579, r = 0.473, p <0.0001), and significant correlation between DI and Child-Pugh scores was observed (r = 0.411, p = 0.001). PP was significantly different with respect to nodule size (p < 0.05), but HV-waveform changes were not significantly correlated with pathological changes. CONCLUSION: In patients with PHT, a monophasic HV waveform indicates higher portal pressure. Furthermore, quantitative indicator DI can reflect both higher portal pressure and more severe liver dysfunction. Flattening of HV waveforms accompanied by an increase in the HAPI and decrease in PVVel support the hypothesis that histological changes reducing HV compliance be the cause of abnormality of Doppler HV waveforms from the hemodynamic angle.

Noninvasive assessment of influence of resistant respiration on blood flow velocities across the cardiac valves in humans--a quantification study by echocardiography.

UNLABELLED: The aim of our study is to quantitatively investigate influence of the intrathoracic pressure change on the four cardiac valves' velocities and further verify a new proposal of the mechanism of respiratory influence on hemodynamics. METHODS: Thirty healthy volunteers with no cardiopulmonary diseases were included. The intrathoracic pressure changes were measured with self-designed device. The velocity across the four cardiac valves during spontaneous respiration and with the intrathoracic pressure change at -4, -8, and -12 mmHg, respectively, were recorded simultaneously with the electrocardiogram and respiratory curve. The respiratory variation indices (RVIs) were calculated. The average RVIs of mitral, aortic, tricuspid, and pulmonary valves were 12.54%, 13.19%; 6.23%, 8.27%; 20.27%, 24.36%; and 6.45%, 7.69% with intrathoracic pressure change at -8 mmHg and -12 mmHg, respectively. All the above parameters have a significant difference from those during spontaneous respiration (P < 0.01 or P < 0.001). We concluded that it might be the respiratory intrathoracic pressure change that causes the change of the velocity across the valves.