Reference values of carotid intima-media thickness and arterial stiffness in Chinese adults based on ultrasound radio frequency signal: A nationwide, multicenter study.

BACKGROUND: Carotid intima-media thickness (IMT) and diameter, stiffness, and wave reflections, are independent and important clinical biomarkers and risk predictors for cardiovascular diseases. The purpose of the present study was to establish nationwide reference values of carotid properties for healthy Chinese adults and to explore potential clinical determinants. METHODS: A total of 3053 healthy Han Chinese adults (1922 women) aged 18-79 years were enrolled at 28 collaborating tertiary centers throughout China between April 2021 and July 2022. The real-time tracking of common carotid artery walls was achieved by the radio frequency (RF) ultrasound system. The IMT, diameter, compliance coefficient, ß stiffness, local pulse wave velocity (PWV), local systolic blood pressure, augmented pressure (AP), and augmentation index (AIx) were then automatically measured and reported. Data were stratified by age groups and sex. The relationships between age and carotid property parameters were analyzed by Jonckheere-Terpstra test and simple linear regressions. The major clinical determinants of carotid properties were identified by Pearson's correlation, multiple linear regression, and analyses of covariance. RESULTS: All the parameters of carotid properties demonstrated significantly age-related trajectories. Women showed thinner IMT, smaller carotid diameter, larger AP, and AIx than men. The ß stiffness and PWV were significantly higher in men than women before forties, but the differences reversed after that. The increase rate of carotid IMT (5.5 µm/year in women and 5.8 µm/year in men) and diameter (0.03 mm/year in both men and women) were similar between men and women. For the stiffness and wave reflections, women showed significantly larger age-related variations than men as demonstrated by steeper regression slopes (all P for age by sex interaction <0.05). The blood pressures, body mass index (BMI), and triglyceride levels were identified as major clinical determinants of carotid properties with adjustment of age and sex. CONCLUSIONS: The age- and sex-specific reference values of carotid properties measured by RF ultrasound for healthy Chinese adults were established. The blood pressures, BMI, and triglyceride levels should be considered for clinical application of corresponding reference values.

Application value of high-frequency ultrasonography in endoscopic retrograde appendicitis therapy for pediatric acute appendicitis.

BACKGROUND: Endoscopic retrograde appendicitis therapy (ERAT) is a new method of treating acute appendicitis that has emerged in recent years in children, but the application of radiological examination in the diagnosis and treatment of pediatric diseases is greatly limited. Therefore, high-frequency ultrasonography imaging has attracted more and more attention because of its advantages such as non-invasiveness, no radiation, and a simpler procedure. This study aims to explore the application value of high-frequency ultrasonography in ERAT for pediatric acute appendicitis. METHODS: A retrospective analysis was conducted on 136 children admitted to our hospital from January 2020 to October 2021 who were definitively diagnosed with acute appendicitis and underwent endoscopic retrograde intra-appendiceal irrigation treatment under the guidance of high-frequency ultrasonography. They were divided into the preschool age group (< 6 years) and school age group (≥ 6 years) according to age. Before the operation and at 1-2 days after ERAT, the external diameter of the appendix, as well as the thickness of the intestinal wall, mucosal layer, and muscular layer in each group were measured by high-frequency ultrasonography and recorded in detail. During the operation, a stent was placed under real-time guidance, and the situation in the cavity was observed. The clinical data of the two groups of children before and after the operation were collected, and the recurrence status after treatment was followed up. RESULTS: Endoscopic treatment was completed in 131 patients with a success rate of 96.32%. There was no significant difference between the two groups in appendix diameter, intestinal wall, or muscular layer after the operation when compared to those before the operation (p > 0.05), but there was a significant difference in the mucosal thickness after operation when compared to before the operation (p < 0.05). Abdominal pain in the two groups was significantly relieved immediately after the operation, and the white blood cell count returned to normal, with a significant difference before and after the ERAT operation (p < 0.05). CONCLUSION: Endoscopic intra-appendiceal irrigation under the guidance of high-frequency ultrasonography is a real-time and convenient method that is safe and effective in treating pediatric acute appendicitis.

Preparation of multifunctional nanobubbles and their application in bimodal imaging and targeted combination therapy of early pancreatic cancer.

Pancreatic cancer will gradually become the second leading cause of cancer death due to its poor suitability for surgical treatment, frequent recurrence and metastasis, and insensitivity to radiotherapy and chemotherapy. Strategies for precise early detection and effective targeted treatment of pancreatic cancer are urgently needed. Because of its unique advantages, molecular targeted contrast-enhanced ultrasound imaging (CEUI) has generated new opportunities to overcome this challenge. The aim of this study was to explore multifunctional nanobubbles named IR780-NBs-DTX as novel ultrasound contrast agents (UCAs) for dual-mode targeted imaging and photothermal ablation combined with chemotherapy for pancreatic cancer. An optimized "film hydration method" was used to prepare IR780-NBs-DTX in this research. The characteristics and ability of the new UCAs were detected via in vitro, in vivo and ex vivo experiments. The initial dose of 0.15 mg IR-780 iodide/1.0 mg DTX was considered to be the best formula for IR780-NBs-DTX, and the concentration of 6 ×106 bubbles/mL was best for CEUI. The excellent characteristics of IR780-NBs-DTX, including a uniform nanoscale particle size (349.8± 159.1 nm, n= 3), good performance in dual-mode imaging, high stability and reliable biocompatibility, were also proven. In the in vitro cell experiments, IR780-NBs-DTX targeted more pancreatic cancer cells than the control treatments, and the targeting rate was approximately 95.6± 1.7%. Under irradiation with an 808 nm laser, most cells died. Furthermore, the in vivo study demonstrated that IR780-NBs-DTX could precisely detect pancreatic cancer through near infrared fluorescence (NIRF) imaging and CEUI, and the tumor almost disappeared at 18 days after combined treatment. In ex vivo experiments, immunohistochemistry (IHC) and immunofluorescence (IF) showed that the expression of HSP70 increased and that of PCNA decreased, and many apoptotic tumor cells were observed by TUNEL staining in the IR780-NBs-DTX group. The newly prepared IR780-NBs-DTX are novel nanosized UCAs with high efficiency for dual-mode molecular targeted imaging and combined therapy, and they may have future potential applications in the precise detection and effective targeted therapy of small and metastatic lesions in the early stage of pancreatic cancer.

Novel biomimetic dual-mode nanodroplets as ultrasound contrast agents with potential ability of precise detection and photothermal ablation of tumors.

PURPOSE: Molecule-targeted ultrasound imaging has attracted extensive attention for precise diagnosis and targeted therapy of tumors. The aim of this research is to prepare novel biomimetic dual-mode nanoscale ultrasound contrast agents (UCAs), which can not only evade the immune clearance of reticuloendothelial system, but also have the potential ability of precise detection and photothermal ablation of tumors. METHODS: In this study, for the first time, the novel biomimetic UCAs were prepared by encapsulating liquid perfluorohexanes with red blood cell membranes carrying IR-780 iodide and named IR780-RBCM@NDs. The characteristics of that were verified through the particle size analyzer, scanning electron microscopy, transmission electron microscopy and laser scanning confocal microscopy. The stability of IR780-RBCM@NDs at 37 °C was explored. The abilities of immune escape, dual-mode imaging and photothermal effect for IR780-RBCM@NDs were verified via in vitro experiments. RESULTS: The novel prepared nanodroplets have good characteristics such as mean diameter, zeta potential, and relatively stability. Importantly, the integrin-associated protein expressed on the surface of RBCMs was detected on IR780-RBCM@NDs. Then, compared with control groups, IR780-RBCM@NDs performed excellent immune escape function away from macrophages in vitro. Furthermore, the IR-780 iodide was observed on the new nanodroplets and that was able to perform the dual-mode imaging with near-infrared fluorescence imaging and contrast-enhanced ultrasound imaging after the phase change. Finally, the effective photothermal ablation ability of IR780-RBCM@NDs was verified in tumor cells. CONCLUSION: The newly prepared biomimetic IR780-RBCM@NDs provided novel ideas for evading immune clearance, performing precise diagnosis and photothermal ablation of tumor cells.

A new strategy for accurate targeted diagnosis and treatment of cutaneous malignant melanoma: dual-mode phase-change lipid nanodroplets as ultrasound contrast agents.

BACKGROUND: Currently, effective detection and treatment of cutaneous malignant melanoma (CMM) still face severe challenges. Ultrasound molecular imaging as a noninvasive and easy-to-operate method is expected to bring improvements for tumor detection. PURPOSE: The aim of this research is to prepare novel phase-change ultrasound contrast agents, Nds-IR780, which can perform not only dual-mode molecule-targeted imaging but also targeted photothermal therapy for CMM. METHODS: A double emulsion process was used to prepare the Nds-IR780. Then, the entrapment rate and drug loading of IR-780 iodide in Nds-IR780 were detected by high-performance liquid chromatography. The biocompatibility of Nds-IR780 was evaluated by a CCK-8 assay and the characteristics and stability of that were verified through the particle size analyzer, laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). The abilities of dual-mode molecule-targeted imaging and targeted photothermal therapy for Nds-IR780 were confirmed via the in vitro and in vivo experiments. RESULTS: Nds-IR780 had good size distribution, polydispersity index, stability and biosafety. The in vitro and in vivo experiments confirmed that Nds-IR780 were capable of targeting CMM cells with high affinity (22.4±3.2%) and facilitating dual-mode imaging to detect the primary lesion and sentinel lymph nodes (SLNs) of CMM. Furthermore, the photothermal ablation of CMM mediated by Nds-IR780 was very effective in vivo. CONCLUSION: The newly prepared Nds-IR780 were observed to be effective targeted theranostic probe for the precise detection and targeted treatment of CMM.

FA-NBs-IR780: Novel multifunctional nanobubbles as molecule-targeted ultrasound contrast agents for accurate diagnosis and photothermal therapy of cancer.

Early accurate diagnosis and targeted therapy for cancer are essential to improve the prognosis of patients. With the emergence of molecular imaging, molecule-targeted ultrasound imaging for the non-invasive and precise detection of cancer has attracted increased attention. The investigation of molecule-targeted ultrasound contrast agents (UCAs) with excellent performance is urgently needed. In this study, we synthetized folic acid and IR-780 on self-made nanobubbles and prepared novel UCAs, named FA-NBs-IR780. The results showed that the conjugates had a uniform size distribution (591 ±â€¯52 nm). In vitro and in vivo experiments demonstrated that FA-NBs-IR780 can target tumour cells via dual molecular targeting, perform enhanced-contrast ultrasound imaging and near-infrared fluorescence (NIRF) imaging for the precise detection of tumours, and induce targeted photothermal therapy in lesions irradiated at 808 nm. Ex vivo experiments further confirmed that FA-NBs-IR780 efficiently induced tumour cell apoptosis and inhibited tumour growth. The newly fabricated FA-NBs-IR780 were observed to be molecule-targeted dual-mode UCAs and may have potential applications in early accurate diagnosis and targeted therapy of cancer in the future.

The therapeutic effect in gliomas of nanobubbles carrying siRNA combined with ultrasound-targeted destruction.

BACKGROUND: Nanobubbles (NBs) combined with ultrasound-targeted destruction (UTD) have become promising potential carriers for drug or siRNA delivery. Due to their nano-size, NBs could penetrate tumor blood vessels and accumulate in intercellular spaces so that "sonoporation" induced by UTD would act directly on the tumor cells to increase cell membrane permeability. METHODS: Based on the successful the fabrication of NBs, we synthesized NBs carrying siRNA (NBs-siRNA) by using a biotin-streptavidin system. We then utilized ultrasound irradiation (UI)-targeted NBs-siRNA to improve siRNA transfection and achieve the inhibition of glioma growth. RESULTS: NBs as carriers combined with UI effectively enhanced siRNA transfection and the effect of silencing targeted genes in vitro. Additionally, a better therapeutic effect was shown in the NBs-siRNA with UI group in vivo compared with that of microbubbles (MBs) with UI or NBs-siRNA without UI. CONCLUSION: These results indicated that NBs combined with UTD might be an ideal delivery vector for siRNA to achieve the noninvasive treatment of glioma.

A Novel Bimodal Imaging Agent Targeting HER2 Molecule of Breast Cancer.

Nanobubble (NB), a newly developed nanoscaled ultrasound contrast agent (UCA) for molecular imaging, has been widely researched for these years. Targeting it with functional molecule, nanobubble can adhere selectively to cellular epitopes and receptors outside the vasculature via enhanced permeability and retention (EPR) effect of tumor blood vessel. To enhance the targeting rate of our previous prepared NBs-Affibody for HER2 (+) breast cancer imaging, we introduced a near-infrared fluorescent (NIRF) dye, IR783, in this study to enhance tumor-specific targeting rate and provide a promising modality for dual-mode imaging. The prepared IR783-NBs-Affibody presented a uniform nanoscale size around 482.7 ± 54.3 nm, good biosecurity, and stability over time. The encapsulation efficiency (EE) of IR-783 was 15.09% in the conjugates leading to a successful NIR fluorescence and ultrasound enhancement imaging ex vivo. IR783-NBs-Affibody was able to automatically accumulate on BT474 cells with a highly increased targeting rate of 85.4% compared with previous NBs-Affibody of 26.6%, while Affibody-guided HER2 binding was only found in HER2-positive cell lines (BT474 and T-47D). The newly developed IR783-NBs-Affibody is characterized with favorable HER2 targeting ability and bimodal imaging capability for breast cancer. Thus, IR783-NBs-Affibody holds great potential in molecular diagnosis for patients with breast cancer.

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.

Iron accumulation and microglia activation contribute to substantia nigra hyperechogenicity in the 6-OHDA-induced rat model of Parkinson's disease.

INTRODUCTION: This study aims to explain the mechanisms for the formation of sonographic features of Parkinson's disease (PD) using a 6-hydroxydopamine (6-OHDA) rat model of PD. The iron chelator deferiprone (DFP) was used in the PD model rat to examine the relationship between iron and the echo signal. METHODS: Rat models were created using stereotactic injections of 6-OHDA. DFP was administered intragastrically. Transcranial sonography (TCS) was performed to observe the substantia nigra (SN) echo signal of the brain. Immunofluorescence and iron staining were performed to observe the histological characteristics of the hyperechogenic area. The imaging findings were compared with the histopathological findings. RESULTS: The PD model rat presented a large area of hyperechogenicity in the SN. Ferric ion accumulation and microglia proliferation occurred in the hyperechogenic area. DFP inhibited dopaminergic (DA) neuron necrosis, ferric ion accumulation and microglia proliferation and reduced the hyperechogenic area of the SN. CONCLUSIONS: Both iron aggregation and gliosis contribute to the formation of substantia nigra hyperechogenicity (SNH) in PD. DFP exhibits a neuroprotective effect by inhibiting SNH. Iron deposit and the SNH are correlated with DA neuron necrosis.

Novel dual-mode nanobubbles as potential targeted contrast agents for female tumors exploration.

The purpose of this study was to prepare tumor-specific dual-mode nanobubbles as both ultrasound contrast agents (UCAs) and near-infrared fluorescence (NIRF) imaging agents for female tumors. Recent studies have demonstrated the conjugation of anti-tumor ligands on the surface of nanobubbles for use as molecule-targeting ultrasound contrast agents for tumor visualization. However, this complicated procedure has also posed a challenge to nanobubble stability. Thus, in the present study, we combined the fluorescent dye, NIRF IR-780 iodide, which has lipid solubility and tumor-targeting characteristics, with the phospholipid film of nanobubbles that we constructed. We then characterized the physical features of the IR-780-nanobubbles, observed their tumor-targeting capacity in multiple female tumor cell types in vitro, and verified their capability for use in tumor-specific ultrasound contrast imaging and NIRF imaging in vivo. The results showed that the new IR-780-nanobubbles had a uniform nano-size (442.5 ± 48.6 nm) and stability and that they were safe and effective at NIRF imaging and ultrasound imaging in vitro. The IR-780-nanobubbles were found to automatically accumulate on different female tumor cells in vitro with a considerable targeting rate (close to 40 %) but did not accumulate on cardiac muscle cells used as a negative control. Importantly, the IR-780-nanobubbles can detect female tumors precisely via dual-mode imaging in vivo. In conclusion, the new dual-mode IR-780-nanobubbles are stable and have potential advantages in non-invasive tumor-specific detection for female tumors via contrast-enhanced ultrasound and NIRF imaging.

Nanobubble-Affibody: Novel ultrasound contrast agents for targeted molecular ultrasound imaging of tumor.

Nanobubbles (NBs), as novel ultrasound contrast agents (UCAs), have attracted increasing attention in the field of molecular ultrasound imaging for tumors. However, the preparation of uniform-sized NBs is considered to be controversial, and poor tumor selectivity in in vivo imaging has been reported. In this study, we fabricated uniform nano-sized NBs (478.2 ± 29.7 nm with polydispersity index of 0.164 ± 0.044, n = 3) using a thin-film hydration method by controlling the thickness of phospholipid films; we then conjugated the NBs with Affibody molecules to produce nano-sized UCAs referred to as NB-Affibody with specific affinity to human epidermal growth factor receptor type 2 (HER2)-overexpressing tumors. NB-Affibody presented good ultrasound enhancement, demonstrating a peak intensity of 104.5 ± 2.1 dB under ultrasound contrast scanning. Ex vivo experiments further confirmed that the NB-Affibody conjugates were capable of targeting HER2-expressing tumor cells in vivo with high affinity. The newly prepared nano-sized NB-Affibody conjugates were observed to be novel targeted UCAs for efficient and safe specific molecular imaging and may have potential applications in early cancer quantitative diagnosis and targeted therapy in the future.