Ultrasound contrast agent Sonazoid for the diagnosis of hepatic epithelioid angiomyolipoma: a case report

Background An angiomyolipoma usually occurs in the kidneys and rarely in the liver. Hepatic epithelioid angiomyolipoma (HEAML), a rare variant of angiomyolipoma, possesses malignant potential and mimics the imaging features of hepatocellular carcinoma. Sonazoid® (perfluorobutane microbubbles), a new contrast agent that facilitates hepatic parenchyma-specific Kupffer phase imaging on contrast-enhanced ultrasonography (CEUS), is useful for the detection and characterization of focal liver lesions. Case presentation A 30-year-old man with HEAML underwent CEUS using Sonazoid®, in which new concepts for ultrasonography-based differentiation between HEAML and hepatocellular carcinoma were applied. Conclusions This case report provides clinicians and radiologists with a reference for distinguishing HEAML from hepatocellular carcinoma based on CEUS using Sonazoid®.

Expression and purification of a native Thy1-single-chain variable fragment for use in molecular imaging

Molecular imaging using singlechain variable fragments (scFv) of antibodies targeting cancer specific antigens have been considered a non-immunogenic approach for early diagnosis in the clinic. Usually, production of proteins is performed within Escherichia coli. Recombinant proteins are either expressed in E. coli cytoplasm as insoluble inclusion bodies, that often need cumbersome denaturation and refolding processes, or secreted toward the periplasm as soluble proteins that highly reduce the overall yield. However, production of active scFvs in their native form, without any heterologous fusion, is required for clinical applications. In this study, we expressed an anti-thymocyte differentiation antigen-scFv (Thy1-scFv) as a fusion protein with a N-terminal sequence including 3 × hexa-histidines, as purification tags, together with a Trx-tag and a S-tag for enhanced-solubility. Our strategy allowed to recover ~ 35% of Thy1-scFv in the soluble cytoplasmic fraction. An enterokinase cleavage site in between Thy1-scFv and the upstream tags was used to regenerate the protein with 97.7 ± 2.3% purity without any tags. Thy1-scFv showed functionality towards its target on flow cytometry assays. Finally, in vivo molecular imaging using Thy1-scFv conjugated to an ultrasound contrast agent (MBThy1-scFv) demonstrated signal enhancement on a transgenic pancreatic ductal adenocarcinoma (PDAC) mouse model (3.1 ± 1.2 a.u.) compared to non-targeted control (0.4 ± 0.4 a.u.) suggesting potential for PDAC early diagnosis. Overall, our strategy facilitates the expression and purification of Thy1-scFv while introducing its ability for diagnostic molecular imaging of pancreatic cancer. The presented methodology could be expanded to other important eukaryotic proteins for various applications, including but not limited to molecular imaging.

Effects of Ultrasound Contrast Agent-Mediated Nerve Growth Factor on Apoptosis of Retinal Ganglion Cells in Mice with Glaucoma

With an increasing incidence in recent years, glaucoma (GL) has gradually become a global public health problem for humans of all ages. Nerve growth factor (NGF) eye drops, with well-documented stable effect in the treatment of GL, can be potentiated by the administration of NGF drugs via ultrasound contrast agent (UCA). This study analyzed the efficacy of NGF+UCA on GL mice and the influencing mechanism on retinal ganglion cells and further explored the pathological changes of GL mice under different UCA irradiation duration. In this study, we established GL mouse models and treated the mouse with NGF+UCA. The effect of NGF+UCA on intraocular pressure in mice was observed; the flash visual evoked potential of mice was compared; the changes of retinal structure, inflammation index, and oxidative stress index were observed, and autophagic protein levels were tested. Finally, the influence of UCA irradiation duration on GL symptoms was observed. The results showed that the intraocular pressure of mice decreased greatly, while their flash visual evoked potential and nervous layer of retina increased, and their ganglion cells showed stronger proliferation activity and weaker apoptosis and autophagy, indicating that UCA-mediated NGF can strongly improve the pathological condition of GL mice. In addition, PI3K/AKT pathway-associated proteins were inhibited in retina under the intervention of NGF+UCA, which further suggests that the influence of UCA-mediated NGF on GL is achieved by inhibiting autophagy of retinal ganglion cells and enhancing their apoptosis via the PI3K/AKT signaling pathway. Moreover, we found that in the treatment of GL, three weeks of UCA irradiation and six weeks caused no significant difference in the pathological manifestations and ganglion cells of mice, while after six weeks of irradiation, the level of NLRP3 in mice increased. In conclusion, UCA-mediated NGF can significantly improve the pathological condition of GL mice and improve the apoptosis of retinal ganglion cells by inhibiting autophagy, which is associated with the inhibition of the PI3K/AKT signal pathway. In terms of selection of UCA irradiation duration, three weeks of irradiation is enough to yield good clinical results.

Preparation of Novel Bi-Modal Nano Contrast Agent and Its Application in Diagnosis of Breast Cancer

In the study, a new ultrasound contrast agent was used in the above diagnosis. Specifically, PLGA nanoparticles (PNA) loaded with Au nanorods and perfluorohexane (PFH) were prepared by the double emulsification method, and then the aptamer (APT) and PNA were connected by the carbodiimide method to obtain dualmodal ultrasound/photoacoustic targeting contrast agent (APT-PNA). Subsequently, physical characterization was performed on the prepared material, and then a fluorescence microscope was used to detect in vitro binding to breast cancer MCF-7 cells, with the normal nanoparticle group, HELA cell group, and APT interference group as controls. On this basis, it was used for the SLNB of breast cancer patients. The results showed that, the average particle size of APT-PNA was (468.5±23.6) nm, and the connection rate between the APT and the PNA reached 95.68%. After laser irradiation, the photo-induced phase changes of the APT-PNA were obvious. The APT-PNA aggregated around and bound firmly to breast cancer MCF-7 cells, while other control groups did not show obvious specific binding. After using APT-PNA, the ultrasound signal and photoacoustic signal were obviously enhanced than before irradiation. Of the 40 patients who participated in the trial, 37 developed lymphatic imaging, with an imaging rate of 92.5%, and 32 of the 37 patients with lymphatic imaging developed lymph node imaging, with a success rate of 86.5%.

Evaluation of Microwave Ablation in 4T1 Breast Tumor by a Novel VEFGR2 Targeted Ultrasound Contrast Agents

ObjectivesA novel ultrasound contrast agent (UCA) VEGFR2-targeting iron-doped silica (SiO2) hollow nanoparticles (VEGFR2-PEG-HSNs-Fe NPs) was prepared and applied in microwave ablation for breast cancer to investigate its value in the evaluation of effectiveness after tumor ablation.MethodsVEGFR2-PEG-HSNs-Fe NPs were prepared by using nano-SiO2, which was regarded as a substrate and etched by ferrous acetate, and then modified with anti-VEGFR2 antibody. Laser confocal microscope and flow cytometry were used to observe its main physicochemical properties, and biological safety was also investigated. After the xenograft tumor was treated with microwave ablation, the extent of perfusion defect was evaluated by ultrasound by injecting VEGFR2-PEG-HSNs-Fe NPs.ResultsThe average particle size of VEGFR2-PEG-HSNs-Fe was 276.64 ± 30.31 nm, and the surface potential was −13.46 ± 2.83 mV. In vitro, the intensity of ultrasound signal increased with UCA concentration. Good biosafety was performed in in vivo and in vitro experiments. The enhanced ultrasound signal was detected in tumors after injection of VEGFR2-PEG-HSNs-Fe NPs, covering the whole tumor. The lesions, which were incompletely ablated, presented as contrast agent perfusion at the periphery of the tumor, and contrast enhanced ultrasound (CEUS) was performed again after complementary ablation. It was confirmed that all the lesions were completely ablated.ConclusionNano-targeted UCAs VEGFR2-PEG-HSNs-Fe NPs had good biosafety and ability of specific imaging, which might be used as a contrast agent in CEUS to evaluate the efficacy of tumor ablation.