Neovascularization of hepatocellular carcinoma in a nude mouse orthotopic liver cancer model: a morphological study using X-ray in-line phase-contrast imaging

Progress of Ultrasound Techniques in the Evaluation of Carotid Vulnerable Plaque Neovascularization

BACKGROUND

The rupture and detachment of unstable plaques in the carotid artery can cause embolism in the cerebral artery, leading to acute cerebrovascular events. Intraplaque neovascularization (IPN) is a very important contributor to carotid plaque instability, and its evolution plays a key role in determining the outcome of vulnerable plaques. Ultrasound techniques, represented by contrast-enhanced ultrasound (CEUS) and superb microvascular imaging (SMI), are reported to be non-invasive, rapid, and effective techniques for the semi-quantitative or quantitative evaluation for IPN. Although ultrasound techniques have been widely applied in the detection of carotid plaque stability, it has been limited owing to the lack of unified IPN quantitative standards.

SUMMARY

This review summarizes the application and semi-quantitative/quantitative diagnostic standards of ultrasound techniques in evaluating IPN and looks forward to the prospects of the future research. With the development of novel techniques like artificial intelligence, ultrasound will offer appropriate selections for achieving more accuracy diagnosis.

KEY MESSAGES

A large number of studies have used CEUS and SMI to detect IPN and perform semi-quantitative grading to predict the occurrence of diseases such as stroke and to accurately assess drug efficacy based on rating changes. These studies have made great progress at this stage, but more accurate and intelligent quantitative imaging methods should become the future development goal.

SPAG5, the upstream protein of Wnt and the target of curcumin, inhibits hepatocellular carcinoma

The inhibitory role of curcumin on sperm-associated antigen 5 (SPAG5) and its effects on the cancer‑related Wnt classical signaling pathway has been previously demonstrated. Nevertheless, research on the modulatory role of curcumin on the Wnt signaling pathway by acting on SPAG5 has yet to be reported. The activation of the Wnt/β‑catenin pathway is frequently observed in patients suffering from hepatocellular carcinoma (HCC), suggesting that small molecular drugs that target Wnt could present a promising therapeutic strategy. However, these drugs often result in substantial side effects. In the present study, the presence of SPAG5 in the cancer tissues of patients with HCC and cell lines was validated using immunohistochemistry, cellular immunofluorescence, reverse transcription‑quantitative polymerase chain reaction, and western blot analyses. Subsequently, the effect of SPAG5 and the regulatory role of curcumin on SPAG5 and the Wnt/β‑catenin pathway were examined using cell function tests, flow cytometry, and western blotting. Techniques of gene knockout and overexpression were employed. The findings revealed a significant overexpression of SPAG5 in the cancer tissues of patients with HCC. Both the mRNA and protein levels of SPAG5 in Huh7 and HCCLM3 cell lines were markedly elevated. Treatment with curcumin led to a decrease in SPAG5 expression, while also inhibiting cell migration and promoting apoptosis. Additionally, suppression of SPAG5 expression resulted in the decreased expression of β‑catenin. Furthermore, curcumin was observed to reduce the expression of cyclin D1 in SPAG5‑overexpressing cell lines. However, the degree of inhibition was diminished once SPAG5 expression was silenced. These initial findings indicate that SPAG5 may function as an upstream regulatory protein of the Wnt/β‑catenin pathway, hence offering a potential alternative target for HCC. Moreover, as curcumin has the capacity to inhibit Wnt via suppressing SPAG5, it could potentially serve as a natural drug component for early intervention and treatment of HCC.

Reduced volume of diabetic pancreatic islets in rodents detected by synchrotron X-ray phase-contrast microtomography and deep learning network

The pancreatic islet is a highly structured micro-organ that produces insulin in response to rising blood glucose. Here we develop a label-free and automatic imaging approach to visualize the islets in situ in diabetic rodents by the synchrotron radiation X-ray phase-contrast microtomography (SRμCT) at the ID17 station of the European Synchrotron Radiation Facility. The large-size images (3.2 mm × 15.97 mm) were acquired in the pancreas in STZ-treated mice and diabetic GK rats. Each pancreas was dissected by 3000 reconstructed images. The image datasets were further analysed by a self-developed deep learning method, AA-Net. All islets in the pancreas were segmented and visualized by the three-dimension (3D) reconstruction. After quantifying the volumes of the islets, we found that the number of larger islets (=>1500 μm³) was reduced by 2-fold (wt 1004 ± 94 vs GK 419 ± 122, P < 0.001) in chronically developed diabetic GK rat, while in STZ-treated diabetic mouse the large islets were decreased by half (189 ± 33 vs 90 ± 29, P < 0.001) compared to the untreated mice. Our study provides a label-free tool for detecting and quantifying pancreatic islets in situ. It implies the possibility of monitoring the state of pancreatic islets in vivo diabetes without labelling.

Micro-morphological feature visualization, auto-classification, and evolution quantitative analysis of tumors by using SR-PCT

Tissue micro‐morphological abnormalities and interrelated quantitative data can provide immediate evidences for tumorigenesis and metastasis in microenvironment. However, the multiscale three‐dimensional nondestructive pathological visualization, measurement, and quantitative analysis are still a challenging for the medical imaging and diagnosis. In this work, we employed the synchrotron‐based X‐ray phase‐contrast tomography (SR‐PCT) combined with phase‐and‐attenuation duality phase retrieval to reconstruct and extract the volumetric inner‐structural characteristics of tumors in digesting system, helpful for tumor typing and statistic calculation of different tumor specimens. On the basis of the feature set including eight types of tumor micro‐lesions presented by our SR‐PCT reconstruction with high density resolution, the AlexNet‐based deep convolutional neural network model was trained and obtained the 94.21% of average accuracy of auto‐classification for the eight types of tumors in digesting system. The micro‐pathomophological relationship of liver tumor angiogenesis and progression were revealed by quantitatively analyzing the microscopic changes of texture and grayscale features screened by a machine learning method of area under curve and principal component analysis. The results showed the specific path and clinical manifestations of tumor evolution and indicated that these progressions of tumor lesions rely on its inflammation microenvironment. Hence, this high phase‐contrast 3D pathological characteristics and automatic analysis methods exhibited excellent recognizable and classifiable for micro tumor lesions.

Gompertz tracking of the growth trajectories of the human-liver-cancer xenograft-tumors in nude mice

BACKGROUND AND OBJECTIVE

The accurate tracking of the growth trajectories of the human-liver-cancer xenograft-tumors in nude mice is an important prerequisite for the effective use of relevant trial results. Our objective is first to find out whether the Gompertz model can accurately track the growth trajectories of the xenograft-tumors in the non-target control group, Gsk3β knockdown, and c-Myc knockdown groups; secondly, to verify the effect of knocking down Gsk3β or c-Myc on the growth of xenograft-tumors and reveal the mechanism; finally, to demonstrate the 100-day Gompertz growth trajectory, which is a complete growth process with two phases and three stages.

METHODS

The 18 male specific-pathogen-free (SPF) BALB/c nude mice were randomly divided into three groups and different interventions were performed to establish the non-target control, Gsk3β knockdown, and c-Myc knockdown groups. The volumes of the xenograft-tumors were measured from day 14 to day 30 after transplantation. The first 30-days and the whole 100-days of Gompertz growth trajectories of the xenograft-tumors were obtained respectively, and the growth assessment indicators of each group were calculated based on the parameters of the Gompertz model.

RESULTS

1) The Gompertz model can accurately track the growth trajectories of xenograft-tumors in the non-target control, Gsk3β knockdown, and c-Myc knockdown groups; 2) knocking down Gsk3β or c-Myc can inhibit the growth of xenograft-tumors. It is the combined effect of growth-promoting factor, growth inhibitory factor, and the delay of angiogenesis, of which the delay of angiogenesis plays a decisive role; 3) the 100-day Gompertz growth trajectory can provide complete information about the two phases and three stages of xenograft-tumor growth. Therefore, it is strongly recommended that nude mouse trials be extended from 30 days (currently widely accepted) to 100 days.

CONCLUSIONS

The Gompertz model can well reveal the growth pattern of the human-liver-cancer xenograft-tumors in nude mice. Combined with the growth assessment indicators obtained from the Gompertz model parameters, one can further clarify the mechanism that affects the growth of xenograft-tumors. The Gompertz tracking of the growth trajectories of the human-liver-cancer xenograft-tumors in nude mice has broad application prospects in the fields of basic research, drug verification, and clinical treatment, etc.

Synchrotron Radiation-Based Three-Dimensional Visualization of Angioarchitectural Remodeling in Hippocampus of Epileptic Rats

Characterizing the three-dimensional (3D) morphological alterations of microvessels under both normal and seizure conditions is crucial for a better understanding of epilepsy. However, conventional imaging techniques cannot detect microvessels on micron/sub-micron scales without angiography. In this study, synchrotron radiation (SR)-based X-ray in-line phase-contrast imaging (ILPCI) and quantitative 3D characterization were used to acquire high-resolution, high-contrast images of rat brain tissue under both normal and seizure conditions. The number of blood microvessels was markedly increased on days 1 and 14, but decreased on day 60 after seizures. The surface area, diameter distribution, mean tortuosity, and number of bifurcations and network segments also showed similar trends. These pathological changes were confirmed by histological tests. Thus, SR-based ILPCI provides systematic and detailed views of cerebrovascular anatomy at the micron level without using contrast-enhancing agents. This holds considerable promise for better diagnosis and understanding of the pathogenesis and development of epilepsy.

A Nude Mouse Model of Orthotopic Liver Transplantation of Human Hepatocellular Carcinoma HCCLM3 Cell Xenografts and the Use of Imaging to Evaluate Tumor Progression

Background

This study aimed to develop a nude mouse model of orthotopic liver transplantation of HCCLM3 human hepatocellular carcinoma (HCC) cell xenografts and the use of imaging and histology to evaluate tumor development and progression.

Material/Methods

HCCLM3 cells were injected subcutaneously into 25 healthy male athymic BALB/c (nu/nu) nude mice. The tumors that developed were transplanted into the liver of a new set of nude mice. After four weeks and six weeks, the mice were imaged using ultrasound (US), software-assisted contrast-enhanced ultrasound (CEUS), fluorodeoxyglucose-positron emission tomography (FDG-PET). Histology was performed on the liver and liver tumors, and included immunohistochemistry for vascular endothelial growth factor (VEGF), CD31, CD34, and α-smooth muscle actin (α-SMA).

Results

The success rate for orthotopic tumor transplantation in the mouse liver was 90% (18/20). Liver tumors measured 11.8±2.6 mm in diameter and 525.9±250.8 mm3 in volume on the sixth week. CEUS showed rapid wash-in and washout in the liver tumors, and PET showed low tumor cell metabolism. Bone metastases were present in 45% (9/20) of mice in the sixth week. Immunohistochemistry showed positive expression for VEGF, CD31, CD34, and α-SMA.

Conclusions

The nude mouse orthotopic liver transplantation model of human HCC was shown to be a reliable model that has the potential for future research on the pathogenesis and progression of HCC and studies on drug development.

Characterization of microvessels and parenchyma in in-line phase contrast imaging CT: healthy liver, cirrhosis and hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a cancer with a poor prognosis, and approximately 80% of HCC cases develop from cirrhosis. Imaging techniques in the clinic seem to be insufficient for revealing the microstructures of liver disease. In recent years, phase contrast imaging CT (PCI-CT) has opened new avenues for biomedical applications owing to its unprecedented spatial and contrast resolution. The aim of this study was to present three-dimensional (3D) visualization of human healthy liver, cirrhosis and HCC using a PCI-CT technique called in-line phase contrast imaging CT (ILPCI-CT) and to quantitatively evaluate the variations of these tissues, focusing on the liver parenchyma and microvasculature.

Methods

Tissue samples from 9 surgical specimens of normal liver (n=3), cirrhotic liver (n=2), and HCC (n=4) were imaged using ILPCI-CT at the Shanghai Synchrotron Radiation Facility (SSRF) without contrast agents. 3D visualization of all ex vivo liver samples are presented. To quantitatively evaluate the vessel features, the vessel branch angles of each sample were clearly depicted. Additionally, radiomic features of the liver parenchyma extracted from the 3D images were measured. To evaluate the stability of the features, the percent coefficient of variation (%COV) was calculated for each radiomic feature. A %COV <30 was considered to be low variation. Finally, one-way ANOVA, followed by Tukey's test, was used to determine significant changes among the different liver specimens.

Results

ILPCI-CT allows for a clearer view of the architecture of the vessels and reveals more structural details than does conventional radiography. Combined with the 3D visualization technique, ILPCI-CT enables the acquisition of an accurate description of the 3D vessel morphology in liver samples. Qualitative descriptions and quantitative assessment of microvessels demonstrated clear differences among human healthy liver, cirrhotic liver and HCC. In total, 38 (approximately 51%) radiomic features had low variation, including 11 first-order features, 16 GLCM features, 6 GLRLM features and 5 GLSZM features. The differences in the mean vessel branch angles and 3 radiomic features (first-order entropy, GLCM-inverse variance and GLCM-sum entropy) were statistically significant among the three groups of samples.

Conclusions

ILPCI-CT may allow for morphologic descriptions and quantitative evaluation of vessel microstructures and parenchyma in human healthy liver, cirrhotic liver and HCC. Vessel branch angles and radiomic features extracted from liver parenchyma images can be used to distinguish the three kinds of liver tissues.

Osthole attenuates angiogenesis in an orthotopic mouse model of hepatocellular carcinoma via the downregulation of nuclear factor-κB and vascular endothelial growth factor

Osthole has been demonstrated to have antitumor activity. Previous studies by our group indicated that osthole effectively inhibited tumor growth in hepatocellular carcinoma (HCC) through the induction of apoptosis and enhancement of antitumor immune responses in mice. The importance of angiogenesis in the proliferation, invasion and metastasis of tumor cells in HCC is well established. The present study aimed to investigate the effects of osthole on angiogenesis in an orthotopic mouse model of HCC. Orthotopic HCC in mice was established, and osthole at 61, 122 and 244 mg/kg was administered intraperitoneally once daily to the tumor-bearing mice for 14 consecutive days. Immunohistochemistry was performed to analyze the microvessel density (MVD) of tissues, and the level of vascular endothelial growth factor (VEGF) was measured by ELISA. The protein levels of nuclear factor-κB (NF-κB) p65 and IκB-α were also detected by western blotting. MVD was positively correlated with tumor weight in the orthotopic mouse model of HCC. Osthole administration significantly decreased MVD in tumor and adjacent tissues, and inhibited tumor growth. Furthermore, osthole downregulated the expression of VEGF and NF-κB p65, and upregulated IκB-α expression in tumor and adjacent tissues. To the best of our knowledge, the results of the present study demonstrated for the first time that osthole inhibits angiogenesis in an orthotopic mouse model of HCC, which may be one of the mechanisms underlying the anti-HCC activity of osthole, which in turn may be mediated by the NF-κB/VEGF signaling pathway. Therefore, osthole, a potential angiogenesis inhibitor and immune system enhancer, may be a promising lead compound for the treatment of HCC.