Effect of Incomplete Cryoablation and Matrix Metalloproteinase Inhibition on Intratumoral CD8+ T-Cell Infiltration in Murine Hepatocellular Carcinoma.

Background Image-guided tumor ablation is the first-line therapy for early-stage hepatocellular carcinoma (HCC), with ongoing investigations into its combination with immunotherapies. Matrix metalloproteinase (MMP) inhibition demonstrates immunomodulatory potential and reduces HCC tumor growth when combined with ablative treatment. Purpose To evaluate the effect of incomplete cryoablation with or without MMP inhibition on the local immune response in residual tumors in a murine HCC model. Materials and Methods Sixty 8- to 10-week-old female BALB/c mice underwent HCC induction with use of orthotopic implantation of syngeneic Tib-75 cells. After 7 days, mice with a single lesion were randomized into treatment groups: (a) no treatment, (b) MMP inhibitor, (c) incomplete cryoablation, and (d) incomplete cryoablation and MMP inhibitor. Macrophage and T-cell subsets were assessed in tissue samples with use of immunohistochemistry and immunofluorescence (cell averages calculated using five 1-µm2 fields of view [FOVs]). C-X-C motif chemokine receptor type 3 (CXCR3)- and interferon γ (IFNγ)-positive T cells were assessed using flow cytometry. Groups were compared using unpaired Student t tests, one-way analysis of variance with Tukey correction, and the Kruskal-Wallis test with Dunn correction. Results Mice treated with incomplete cryoablation (n = 6) showed greater infiltration of CD206+ tumor-associated macrophages (mean, 1.52 cells per FOV vs 0.64 cells per FOV; P = .03) and MMP9-expressing cells (mean, 0.89 cells per FOV vs 0.11 cells per FOV; P = .03) compared with untreated controls (n = 6). Incomplete cryoablation with MMP inhibition (n = 6) versus without (n = 6) led to greater CD8+ T-cell (mean, 15.8% vs 8.29%; P = .04), CXCR3+CD8+ T-cell (mean, 11.64% vs 8.47%; P = .004), and IFNγ+CD8+ T-cell infiltration (mean, 11.58% vs 5.18%; P = .02). Conclusion In a mouse model of HCC, incomplete cryoablation and systemic MMP inhibition showed increased cytotoxic CD8+ T-cell infiltration into the residual tumor compared with either treatment alone. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Gemmete in this issue.

Experimental VX2 Rabbit Liver Tumor Model in Carbon Tetrachloride-Induced Cirrhosis of the Liver.

Liver cirrhosis is a major underlying factor in the development of hepatocellular carcinoma. Currently, there is an unmet need for midsize experimental vertebrate models that would offer reproducible implantable liver tumors in a cirrhotic liver background. This study establishes a protocol for a syngeneic rabbit model of VX2 liver cancer with underlying liver cirrhosis induced using carbon tetrachloride (CCl4). Male New Zealand white rabbits (n = 3) received CCl4 by intragastric administration once weekly. Concentrations started at 5% v/v CCl4 dissolved in olive oil. CCl4 dosing was progressively increased every week by 2.5% v/v increments for the duration of treatment (16 weeks total). VX2 tumors were then orthotopically implanted into the left hepatic lobe and allowed to grow for 3 weeks. Cross-sectional imaging confirmed the presence of hepatic tumors. Gross and histopathological evaluations showed reproducible tumor growth in the presence of liver cirrhosis in all animals.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) in sickle cell disease vasculopathy.

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is an endothelial receptor for oxidized LDL. Increased expression of LOX-1 has been demonstrated in atherosclerotic lesions and diabetic vasculopathy. In this study, we investigate the expression of LOX-1 receptor in sickle cell disease (SCD) vasculopathy. Expression of LOX-1 in brain vascular endothelium is markedly increased and LOX-1 gene expression is upregulated in cultured human brain microvascular endothelial cells by incubation with SCD erythrocytes. Also, the level of circulating soluble LOX-1 concentration is elevated in the plasma of SCD patients. Increased LOX-1 expression in endothelial cells is potentially involved in the pathogenesis of SCD vasculopathy. Soluble LOX-1 concentration in SCD may provide a novel biomarker for risk stratification of sickle cell vascular complications.

Development of paravertebral pseudoaneurysms following vertebral augmentation: a report of two cases.

Paravertebral pseudoaneurysms are infrequent following vertebral augmentation but can be difficult to manage due to their proximity to the arterial supply of the spinal cord. Here, we present two distinct manifestations of this complication with associated anatomy and management. In the first, a pseudoaneurysm developed following radiofrequency ablation and kyphoplasty at the L2 and L4 levels. Direct puncture embolization initially failed to close the pseudoaneurysm, but stasis was ultimately achieved via trans-arterial embolization. In the second, vertebral augmentation at the T9 and T11-L3 levels was complicated by formation of a pseudoaneurysm fed by a segmental artery and a long paravertebral anastomotic vein. Due to the patient's poor medical status, intervention was not performed. Understanding vertebral arterial anatomy is crucial for preventing and treating vascular injury in vertebral augmentation.

Artificial intelligence in liver diseases: Improving diagnostics, prognostics and response prediction.

Clinical routine in hepatology involves the diagnosis and treatment of a wide spectrum of metabolic, infectious, autoimmune and neoplastic diseases. Clinicians integrate qualitative and quantitative information from multiple data sources to make a diagnosis, prognosticate the disease course, and recommend a treatment. In the last 5 years, advances in artificial intelligence (AI), particularly in deep learning, have made it possible to extract clinically relevant information from complex and diverse clinical datasets. In particular, histopathology and radiology image data contain diagnostic, prognostic and predictive information which AI can extract. Ultimately, such AI systems could be implemented in clinical routine as decision support tools. However, in the context of hepatology, this requires further large-scale clinical validation and regulatory approval. Herein, we summarise the state of the art in AI in hepatology with a particular focus on histopathology and radiology data. We present a roadmap for the further development of novel biomarkers in hepatology and outline critical obstacles which need to be overcome.

Outcomes of Stereotactic Radiosurgery and Immunotherapy in Renal Cell Carcinoma Patients With Brain Metastases.

OBJECTIVE: The impact of immunotherapy and stereotactic radiosurgery (SRS) in treatment of brain metastases (BM) from renal cell carcinoma (RCC) has not been well investigated. MATERIALS AND METHODS: Forty-eight patients with 372 RCC BM were treated with SRS and divided into those ever treated with immunotherapy versus those who never received immunotherapy. Survival and local control (LC) outcomes were studied. χ2 and Mann-Whitney U tests compared categorical and continuous variables, respectively. Kaplan-Meier curves were used to estimate survival and log-rank test was used to compare survival between groups. RESULTS: Immunotherapy and nonimmunotherapy groups contained 29 and 19 patients, respectively. Median follow-up was 23.1 months (range, 6 to 93.8 mo). Demographic and treatment variables were similar except median prescribed margin dose was significantly lower in immunotherapy group (20 vs. 22 Gy, P<0.0001). Median overall survival (OS) was 27.2 months (immunotherapy) and 14.9 months (nonimmunotherapy), P=0.14. Furthermore, patients treated with immune checkpoint inhibitor (ICI) had even better median OS compared with those who never received ICI (33 vs. 16.7 mo, P=0.03). Factors associated with improved LC were use of ICI (P=0.002) and lesion size <1000 mm3 (P=0.046). There was no difference in incidence of radiation necrosis between the 2 groups (P=0.67). CONCLUSIONS: Patients with RCC BM undergoing SRS can experience prolonged survival when treated with ICI. Equally effective LC of BM was achieved when treated with immunotherapy using a 2 Gy decrease in SRS dose without increasing the risk of central nervous system toxicity.

Visualizing Synaptic Transfer of Tumor Antigens among Dendritic Cells.

Generation of tumor-infiltrating lymphocytes begins when tumor antigens reach the lymph node (LN) to stimulate T cells, yet we know little of how tumor material is disseminated among the large variety of antigen-presenting dendritic cell (DC) subsets in the LN. Here, we demonstrate that tumor proteins are carried to the LN within discrete vesicles inside DCs and are then transferred among DC subsets. A synapse is formed between interacting DCs and vesicle transfer takes place in the absence of free exosomes. DCs -containing vesicles can uniquely activate T cells, whereas DCs lacking them do not. Understanding this restricted sharing of tumor identity provides substantial room for engineering better anti-tumor immunity.

A novel framework for segmentation of secretory granules in electron micrographs.

It is still a standard practice for biologists to manually analyze transmission electron microscopy images. This is not only time consuming but also not reproducible and prone to induce subjective bias. For large-scale studies of insulin granules inside beta cells of the islet of Langerhans, an automated method for analysis is essential. Due to the complex structure of the images, standard microscopy segmentation techniques cannot be applied. We present a new approach to segment and measure transmission electron microscopy images of insulin granule cores and membranes from beta cells of rat islets of Langerhans. The algorithm is separated into two broad components, core segmentation and membrane segmentation. Core segmentation proceeds through three steps: pre-segmentation using a novel level-set active contour, morphological cleaning and a refining segmentation on each granule using a novel dual level-set active contour. Membrane segmentation is achieved in four steps: morphological cleaning, membrane sampling and scaling, vector field convolution for gap filling and membrane verification using a novel convergence filter. We show results from our algorithm alongside popular microscopy segmentation methods; the advantages of our method are demonstrated. Our algorithm is validated by comparing automated results to a manually defined ground truth. When the number of granules detected is compared to the number of granules in the ground truth a precision of 91% and recall of 87% is observed. The average granule areas differ by 13.35% and 6.08% for core and membranes respectively, when compared to the average areas of the ground truth. These results compare favorably to previously published data.

Retracing in correlative light electron microscopy: where is my object of interest?

Correlative light electron microscopy (CLEM) combines the strengths of light and electron microscopy in a single experiment. There are many ways to perform a CLEM experiment and a variety of microscopy modalities can be combined either on separate instruments or as completely integrated solutions. In general, however, a CLEM experiment can be divided into three parts: probes, processing, and analysis. Most of the existing technologies are focussed around the development and use of probes or describe processing methodologies that explain or circumvent some of the compromises that need to be made when performing both light and electron microscopy on the same sample. So far, relatively little attention has been paid to the analysis part of CLEM experiments. Although it is an essential part of each CLEM experiment, it is usually a cumbersome manual process. Here, we briefly discuss each of the three above-mentioned steps, with a focus on the analysis part. We will also introduce an automated registration algorithm that can be applied to the analysis stage to enable the accurate registration of LM and EM images. This facilitates tracing back the right cell/object seen in the light microscope in the EM.

Active contour based segmentation for insulin granule cores in electron micrographs of beta islet cells.

Transmission electron microscopy images of beta islet cells contain many complex structures, making it difficult to accurately segment insulin granule cores. Quantification of sub cellular structures will allow biologists to better understand cellular mechanics. Two novel, level set active contour models are presented in this paper. The first utilizes a shape regularizer to reduce oversegmentation. The second contribution is a dual active contour, which achieves accurate core segmentations. The segmentation algorithm proceeds through three stages: an initial rough segmentation using the first contribution, cleaning using morphological techniques and a refining step using the proposed dual active contour. Our method is validated on a set of manually defined ground truths.