Quantitative Dual-Energy CT Image Guidance for Thermochemical Ablation: In Vivo Results in the Rabbit VX2 Model.

PURPOSE: To evaluate the feasibility of using dual-energy computed tomography (CT) and theranostic cesium hydroxide (CsOH) for image guidance of thermochemical ablation (TCA) in a rabbit VX2 tumor model. MATERIALS AND METHODS: In vivo experiments were performed on New Zealand white rabbits, where VX2 tumor fragments (0.3 mL) were inoculated into the right and left flanks (n = 16 rabbits, 32 tumors). Catheters were placed in the approximate center of 1- to 2-cm diameter tumors under ultrasound guidance. TCA was delivered in 1 of 3 treatment groups: untreated control, 5-M TCA, or 10-M TCA. The TCA base reagent was doped with 250-mM CsOH. Dual-energy CT was performed before and after TCA. Cesium (CS)-specific images were postprocessed on the basis of previous phantom calibrations to determine Cs concentration. Line profiles were drawn through the ablation center. Twenty-four hours after TCA, subjects were euthanized, and the resulting damage was evaluated with histopathology. RESULTS: Cs was detected in 100% of treated tumors (n = 21). Line profiles indicated highest concentrations at the injection site and decreased concentrations at the tumor margins, with no Cs detected beyond the ablation zone. The maximum detected Cs concentration ranged from 14.39 to 137.33 mM. A dose-dependent trend in tissue necrosis was demonstrated between the 10-M TCA and 5-M TCA treatment groups (P = .0005) and untreated controls (P = .0089). CONCLUSIONS: Dual-energy CT provided image guidance for delivery, localization, and quantification of TCA in the rabbit VX2 model.

Thermal Ablation Induces Transitory Metastatic Growth by Means of the STAT3/c-Met Molecular Pathway in an Intrahepatic Colorectal Cancer Mouse Model.

Background Systemic protumorigenic effects have been noted after radiofrequency ablation (RFA) of normal liver and have been linked to an interleukin 6/signal transducer and activator of transcription 3 (STAT3)/hepatocyte growth factor (HGF)/tyrosine-protein kinase Met (c-Met)/vascular endothelial growth factor (VEGF) cytokinetic pathway. Purpose To elucidate kinetics of RFA protumorigenic effects on intrahepatic metastatic implantation and growth and determine potential molecular targets for pharmacologic suppression of these effects. Materials and Methods An intrahepatic metastasis model was established by implanting CT26 and MC38 tumor cells into 216 7-8-week-old male Balb/C and C57BL6 mice, respectively, by means of splenic injection. Between June 2017 and March 2019, mice underwent tumor injection, followed 24 hours later by either standardized RFA (70°C ± 1, 5 minutes, 1-cm tip) or a sham procedure (needle placement without heating) (12 animals per arm, n = 48). Next, RFA or sham procedures were performed, followed by splenic tumor cell injection at 1 day, 3 days, or 7 days later (six animals per arm, n = 72). Finally, PHA-665752 and S3I-201 were used to block c-Met or STAT3, respectively, prior to either RFA or sham treatment (six animals per arm, n = 96). Livers were harvested at 14 days for CT26 and 21days for MC38 for tumor quantification. Ki-67 and CD34 immunohistochemistry measured proliferative indexes and microvascular density, respectively. Data were compared with analysis of variance and the two-tailed Student t test. Results RFA performed after tumor cell injection induced increased metastatic tumor number (103 ± 45 vs 52 ± 44 [CT26], P = .009 and 87 ± 51 vs 39 ± 20 [MC38], P = .007), cellular proliferation (P < .001 for both), and intratumoral neovascularization (P < .001 for both), compared with the sham procedure. Tumor cell injection performed 1 day and 3 days after RFA also increased these indexes (P < .05), while no difference was demonstrated for cell injection 7 days after RFA (P > .05). Adjuvant c-Met or STAT3 inhibition reduced intrahepatic metastatic parameters after RFA to baseline (P < .03), equivalent to the sham group (P > .05). Conclusion Radiofrequency ablation of normal liver promotes intrahepatic metastatic implantation and increased growth over a short-lived (1-3 days) temporal window in animal models. This phenomenon can be potentially neutralized with specific inhibition of pathways including hepatocyte growth factor/tyrosine-protein kinase Met and signal transducer and activator of transcription 3. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Nikolic in this issue.

Effect of laparoscopic liver resection versus the open technique on hepatocyte regenerating activity in the rat.

BACKGROUND: Laparoscopic liver resection offers a safe and feasible option primarily for the excision of hepatic neoplasms. Timely recovery of liver volume is a key factor for improving prognosis and post-operative mortality of patients undergone liver resection. The aim of the present study was to compare liver regeneration after laparoscopic over open partial hepatectomy. METHODS: Wistar rats were subjected to laparoscopic 70% hepatectomy (group LAP-HEP), open 70% hepatectomy (group HEP), sham operation (group Sham) or no intervention (group Control). At various timepoints following operation (1 h-2 weeks), the liver was excised to assess relative liver weight, thiobarbituric acid reactive substances (TBARS) levels, mitotic activity, tissue expression of Nuclear Factor-κB (NFκB), Intercellular Adhesion Molecule-1 (ICAM-1) and Vascular Cell Adhesion Molecule-1 (VCAM-1) and the histopathologic profile. RESULTS: No differences were seen in relative liver weight between hepatectomy groups. Mitotic index was increased in all operative study groups, being higher in group LAP-HEP than in group HEP. TBARS levels were higher in group LAP-HEP compared to group HEP. NFκB and VCAM-1 tissue expression scores were increased in all operative study groups with VCAM-1 being higher in group HEP, while ICAM-1 was overexpressed only in hepatectomy groups. Mild histopathologic lesions were noted in hepatectomy groups with the histopathologic score being higher in group HEP (24 h). CONCLUSIONS: Laparoscopic liver resection enhanced hepatocyte mitotic activity which was accompanied by mild oxidative stress and a less pronounced local inflammatory response and tissue injury to that of the open technique.

Hepatic Microwave Ablation-Induced Tumor Destruction and Animal End Point Survival Can Be Improved by Suppression of Heat Shock Protein 90.

OBJECTIVES: To investigate the effect of heat shock protein 90 (HSP90) modulation on tumor necrosis, apoptosis, tumor growth delay, and end point survival by combining microwave ablation (MWA) with an HSP90 inhibitor in a nude mouse model. METHODS: This study was approved by the Ethics Committee. Forty mice with HepG2 subcutaneous xenograft tumors (10 ± 1 mm) were randomized into 4 groups: (1) no treatment, (2) MWA only, (3) the HSP90 inhibitor ganetespib only, and (4) ganetespib combined with MWA. Tumors were harvested 24 hours after treatment, and gross coagulation diameters were measured. The effect of ganetespib on HSP90 and caspase 3 expression in the periablational rim was assessed. Another 40 mice with the same tumors and groupings were observed after treatment. Tumor growth curve and Kaplan-Meier survival analyses were performed with a tumor diameter of 2.2 cm and 40 days of survival as the defined survival end points. RESULTS: Combination treatment significantly increased the coagulation size compared to tumors treated with MWA or ganetespib alone (P < 0.05). The combination of MWA and ganetespib decreased HSP90 expression and increased cleaved caspase 3 expression 24 hours after treatment. Compared with MWA or ganetespib only, combination treatment could lengthen the end point survival and reduce the tumor growth rate. CONCLUSIONS: Modulation of HSP production can improve MWA-induced tumor apoptosis and destruction, reduce residual tumor growth rates, and prolong end point survival.

Potential of Ablation Therapy during Hepatocellular Carcinoma.

BACKGROUND: This study explored the potential of ablation therapy on membrane fluidity changes in diethylnitrosamine (DEN) induced hepatic cancer. METHODS: Male Wistar rats were segregated into four groups viz., normal control, DEN treated, ablation therapy treated, and DEN ablation therapy treated. We assessed the viscosities as well as fluidity parameters in isolated brush border membranes using the membrane extrinsic fluorophore pyrene. RESULTS: DEN treatment successfully induced hepatic cancer in the livers of rats and ablation therapy worked well in terms of therapy. DEN treatment resulted in a significant rise in lipid peroxidation (LPO) and significant decrease in the, reduced glutathione levels (GSH). A significant decrease was also noticed in the activities of glutathione reductase (GR), glutathione transferase (GST), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) following DEN treatment. On the other hand, ablation therapy treatment to DEN-treated rats resulted in a significant decrease in the LPO levels but caused a significant rise in the levels of GSH. Moreover, the activities of GR, GST, SOD, CAT, and GPx showed significant improvement after ablation therapy treatment. The results further demonstrated a marked decrease in membrane microviscosity following DEN treatment. On the other hand, a significant increase was noticed in both excimer/monomer ratio and fluidity parameter in DEN-treated rats. However, membrane microviscosity and the fluidity alterations were significantly restored back to near normal with ablation therapy treatment. CONCLUSIONS: The study, therefore, concluded that ablation therapy holds good therapeutic potential against DEN-induced hepatic cancer.

Targeting STAT3 to Suppress Systemic Pro-Oncogenic Effects from Hepatic Radiofrequency Ablation.

Purpose To (a) identify key expressed genes in the periablational rim after radiofrequency ablation (RFA) and their role in driving the stimulation of distant tumor growth and (b) use adjuvant drug therapies to block key identified mediator(s) to suppress off-target tumorigenic effects of hepatic RFA. Materials and Methods This institutional animal care and use committee-approved study was performed in C57BL6 mice (n = 20) and F344 rats (n = 124). First, gene expression analysis was performed in mice after hepatic RFA or sham procedure; mice were sacrificed 24 hours to 7 days after treatment. Data were analyzed for differentially expressed genes (greater than twofold change) and their functional annotations. Next, animals were allocated to hepatic RFA or sham treatment with or without STAT3 (signal transducer and activator of transcription 3) inhibitor S3I-201 for periablational phosphorylated STAT3 immunohistochemistry analysis at 24 hours. Finally, animals with subcutaneous R3230 adenocarcinoma tumors were allocated to RFA or sham treatment with or without a STAT3 inhibitor (S3I-201 or micellar curcumin, eight arms). Outcomes included distant tumor growth, proliferation (Ki-67 percentage), and microvascular density. Results At 24 hours, 217 genes had altered expression (107 upregulated and 110 downregulated), decreasing to 55 genes (27 upregulated and 28 downregulated) and 18 genes (four upregulated, 14 downregulated) at 72 hours and 7 days, respectively. At 24 hours, STAT3 occurred in four of seven activated pathways associated with pro-oncogenic genes at network analysis. Immunohistochemistry analysis confirmed elevated periablational phosphorylated STAT3 24 hours after RFA, which was suppressed with S3I-201 (percentage of positive cells per field: 31.7% ± 3.4 vs 3.8% ± 1.7; P < .001). Combined RFA plus S3I-201 reduced systemic distant tumor growth at 7 days (end diameter: 11.8 mm ± 0.5 with RFA plus S3I-201, 19.8 mm ± 0.7 with RFA alone, and 15 mm ± 0.7 with sham procedure; P < .001). STAT3 inhibition with micellar curcumin also suppressed postablation stimulation of distant tumor growth, proliferation, and microvascular density (P < .01). Conclusion Gene expression analysis identified multiple pathways upregulated in the periablational rim after hepatic RFA, of which STAT3 was active in four of seven. Postablation STAT3 activation is linked to increased distant tumor stimulation and can be suppressed with adjuvant STAT3 inhibitors. © RSNA, 2017.

Dual-Energy CT-Derived Volumetric Iodine Concentration for the Assessment of Therapeutic Response after Microwave Ablation in a Rabbit Model with Intrahepatic VX2 Tumor.

PURPOSE: To evaluate whether changes in volumetric iodine concentration (VIC) could serve as a suitable predictor of therapeutic response to microwave (MW) ablation in a rabbit intrahepatic VX2 tumor model. MATERIALS AND METHODS: Sixteen intrahepatic VX2 tumors were transplanted in 8 New Zealand White rabbits treated with MW ablation. Contrast-enhanced dual-energy CT scans were obtained at baseline and follow-up. Therapeutic response assessment by modified Response Evaluation Criteria In Solid Tumors (mRECIST), Choi criteria, and VIC changes was performed. An intraclass correlation coefficient (ICC) was used to characterize consistency of assessment results among the criteria used. Technical success was evaluated with explant pathologic findings as a reference. Correlations between technical success and variations in diameter, CT density, and VIC were analyzed. RESULTS: Disease control was observed in 4, 8, and 10 of the 16 tumors per mRECIST, Choi criteria, and VIC changes, respectively. VIC exhibited strong consistency (ICC = 0.807, P < .0001) with Choi criteria. According to explant pathology, technical success was achieved in 10 of the 16 tumors. There was a moderate correlation between VIC changes and technical success (r = 0.532, P = .034), and no correlation was found between technical success and variations in diameter or CT density. CONCLUSIONS: Compared with mRECIST and Choi criteria, dual-energy CT-derived VIC allowed for better prediction of therapeutic response after MW ablation and could provide a potential imaging biomarker of tumor response to MW ablation in patients with hepatocellular carcinoma.

Analysis of laparoscopic laser liver resection in standardized porcine model.

BACKGROUND: Hepatocellular carcinoma is a highly prevalent and lethal primary neoplasia of the liver and metastases of other malignancies affect most frequently the liver. Minimally invasive surgical approach for liver resections is advancing. Dissection of liver parenchyma by laparoscopic technique remains challenging and new technologies are in need. Therefore, we asked whether it is feasible to dissect liver tissue comparably in terms of speed and hemostasis with a non-contact 1.9-µm cw-laser device and whether there are differences in the postoperative healing process compared to a gold standard device (ultrasound aspirator) in an experimental model. METHODS: Laparoscopic laser and ultrasound aspirator standardized partial liver resections were performed in seven pigs. Resection time, hemostasis time, and blood loss were evaluated. After at least 10 days, representative specimen of the resection areas was collected via re-laparoscopy and biopsy and side effects like hematoma, abscess, or bilioma were noted. Histologically, coagulation necrosis margin, granulation tissue zone, tissue fibrosis, and giant cell count were analyzed. RESULTS: Laparoscopic laser liver resection was three times faster compared to the laparoscopic ultrasound aspirator. Blood loss was equal in both groups. No side effects like hematoma or bilioma occurred. Histologically, specimen showed the same expansion of coagulation necrosis zone and granulation tissue. Fibrotic scar could be determined in three cases in both groups, respectively. However, giant cell count was significant higher in the laser resection group. CONCLUSIONS: The 1.9-µm cw-laser device enables a safe and fast liver resection in an experimental pig model compared to a gold standard (ultrasound aspirator) laparoscopic liver resection method. Wound healing is not interfered by laser liver resection.

Irreversible Electroporation versus Radiofrequency Ablation: A Comparison of Local and Systemic Effects in a Small-Animal Model.

Purpose To compare both periablational and systemic effects of two mechanistically different types of ablation: thermal radiofrequency (RF) ablation and electroporative ablation with irreversible electroporation (IRE) in appropriately selected animal models. Materials and Methods Animal experiments were performed according to a protocol approved by the Animal Care Committee of Hebrew University. Female C57BL/6 mice (n = 165) were randomized to undergo either RF or IRE ablation of noncancerous normal liver. The inflammatory response, cell proliferation, interleukin 6 (IL-6) levels, and intactness of vessels in the liver were assessed at 6, 12, and 24 hours and at 3, 7, and 14 days after ablation (n = 122 for mechanistic experiments). Systemic effects were then assessed by comparing tumor formation in an Mdr2-knockout (KO) mouse model (n = 15) and tumor growth in a remote BNL 1ME hepatoma xenograft tumor (n = 28). Results were averaged and evaluated by using two-tailed t tests. Results Although RF ablation was associated with a well-defined periablational inflammatory rim, for IRE, the infiltrate penetrated the ablation zone, largely along persistently patent vessels. Peak IL-6 levels (6 hours after ablation) were 10 and three times higher than at baseline for IRE and RF, respectively (P < .03). Mdr2-KO mice that were treated with IRE ablation had more tumors that were 3 mm or larger than mice treated with RF ablation or sham operation (mean, 3.6 ± 1.3 [standard deviation] vs 2.4 ± 1.1 and 2.2 ± 0.8, respectively; P < .05 for IRE vs both RF ablation and sham operation). For BNL 1ME tumors, both RF and IRE liver ablation reduced tumor growth, with a greater effect noted for IRE (1329 mm(3) ± 586 and 819 mm(3) ± 327 vs 2241 mm(3) ± 548 for sham operation; P < .05) that was accompanied by more infiltrating lymphocytes compared with sham operation (7.6 cells per frame ± 1.9 vs 11.2 ± 2.1 vs 0.3 ± 0.1; P < .05). Conclusion Persistent patency of vasculature within the coagulated zone from IRE increases the area and accumulation of infiltrative cells that is associated with a higher serum IL-6 level than RF ablation. These local changes of IRE induce more robust systemic effects, including both tumorigenic and immunogenic effects. (©) RSNA, 2016 Online supplemental material is available for this article.

Stress Test of Contrast-Enhanced US with Phenylephrine in a Rabbit VX2 Liver Tumor Model: Differentiating Benign Periablational Enhancement from Residual Tumor after Radiofrequency Ablation.

PURPOSE: To differentiate benign periablational enhancement (BPE) from residual tumor after radiofrequency (RF) ablation by using a stress contrast-enhanced ultrasonography (US) test with phenylephrine in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: VX2 tumors were implanted in the livers of 40 rabbits for two experiments. In experiment one, liver tumors from 32 animals were completely ablated. On days 2, 7, 14, and 21 after RF ablation, eight animals were randomly chosen for contrast-enhanced US before and after phenylephrine administration, and the microvessel density (MVD) of BPE at these four time points was assessed. In experiment two, liver tumors from eight animals were partly ablated, and each animal underwent contrast-enhanced US before and after phenylephrine administration on day 7 after RF ablation. Perfusion parameters were observed, including maximum intensity (IMAX), rise time (ie, time between 10% and 90% of IMAX), time to peak, mean transit time, and area under the curve (AUC), along with the profile of time-intensity curves (TICs) in BPE and residual tumor in response to phenylephrine. RESULTS: Among the four time points after ablation, the IMAX and AUC before phenylephrine administration and the MVD of BPE were greatest on day 7 (P < .05). The profile of TICs and the corresponding perfusion parameters in residual tumor did not change significantly in response to phenylephrine. However, those from BPE changed significantly (P < .05). CONCLUSIONS: Contrast-enhanced US with phenylephrine stress may be helpful in differentiating BPE from residual tumor after RF ablation in hepatocellular carcinoma.

Improved disease-free survival and overall survival after fluorescence-guided surgery of liver metastasis in an orthotopic nude mouse model.

BACKGROUND: In the present study, we sought to determine if fluorescence-guided surgery (FGS) would improve survival compared to standard bright light surgery (BLS) in an experimental colorectal liver metastasis nude mouse model. METHODS: Orthotopic nude-mouse models of human HT-29-GFP colon cancer liver metastasis were established in the left lobe of the liver of mice. Fourteen mice with a single liver metastasis were randomized into FGS or BLS groups of seven each. FGS of liver metastasis was performed using a hand-held portable fluorescence imaging system (Dino-Lite) to visualize the GFP fluorescence of the metastasis. The BLS- and FGS-treated mice were followed by weekly fluorescence imaging in order to detect recurrence. RESULTS: The bright fluorescence of GFP provided sufficient illumination to accurately distinguish the margins of the metastasis within the liver. Recurrence occurred in multiple sites including the liver, lung, and other organs in the BLS-treated mice but was significantly reduced in FGS-treated mice. The FGS-treated mice had significantly prolonged disease-free survival (P = 0.001) and overall survival (P = 0.027) compared to BLS-treated mice. CONCLUSION: The results of the present report demonstrate the feasibility and efficacy of FGS for liver metastasis and suggest its important clinical potential.

Multimodality imaging to assess immediate response to irreversible electroporation in a rat liver tumor model.

PURPOSE: To compare changes on ultrasonographic (US), computed tomographic (CT), and magnetic resonance (MR) images after irreversible electroporation (IRE) ablation of liver and tumor tissues in a rodent hepatoma model. MATERIALS AND METHODS: Studies received approval from the institutional animal care and use committee. Forty-eight rats were used, and N1-S1 tumors were implanted in 24. Rats were divided into groups and allocated for studies with each modality. Imaging was performed in normal liver tissues and tumors before and after IRE. MR imaging was performed in one group before and after IRE after hepatic vessel ligation. US images were graded to determine echogenicity changes, CT attenuation was measured (in Hounsfield units), and MR imaging signal-to-noise ratio (SNR) was measured before and after IRE. Student t test was used to compare attenuation and SNR measurements before and after IRE (P < .05 indicated a significant difference). RESULTS: IRE ablation produced greater alterations to echogenicity in normal tissues than in tumors. Attenuation in ablated liver tissues was reduced compared with that in control tissues (P < .001), while small attenuation differences between ablated (42.11 HU ± 2.11) and control (45.14 HU ± 2.64) tumors trended toward significance (P = .052). SNR in ablated normal tissues was significantly altered after IRE (T1-weighted images: pre-IRE, 145.95 ± 24.32; post-IRE, 97.80 ± 18.03; P = .004; T2-weighted images, pre-IRE, 47.37 ± 18.31; post-IRE, 90.88 ± 37.15; P = .023). In tumors, SNR differences before and after IRE were not significant. No post-IRE signal changes were observed after hepatic vessel ligation. CONCLUSION: IRE induces rapid changes on gray-scale US, unenhanced CT, and MR images. These changes are readily visible and may assist a performing physician to delineate ablation zones from the unablated surrounding parenchyma.

Radiofrequency ablation suppresses distant tumour growth in a novel rat model of multifocal hepatocellular carcinoma.

RFA (radiofrequency ablation) is an established therapy for HCC (hepatocellular carcinoma). The multikinase inhibitor sorafenib prolongs survival in advanced HCC. We examined the effects of RFA alone and in combination with sorafenib on a bystanding tumour in a two-tumour rat model of HCC. A total of 80 rats were implanted with two liver tumours and randomized to four treatment groups: vehicle and sham operation (control), sorafenib and sham operation (Sora/Sham), vehicle and RFA (Vh/RFA), and sorafenib and RFA (Sora/RFA) (n=10/group per time point). RFA or sham-operation was performed on the left lobe tumour on day 15. Animals were killed at day 18 and day 30. Non-RFA-targeted right lobe tumours were analysed for angiogenesis, growth factors [HGF (hepatocyte growth factor), EGF (epidermal growth factor) and VEGF (vascular endothelial growth factor)] and infiltrating immune cells (CD3 and CD68). At day 30, the non-RFA-targeted tumours were significantly smaller in all three treatment groups compared with control (Sora/Sham P≤0.0001, Vh/RFA P=0.005 and Sora/RFA P≤0.0001). The smallest tumours were observed in animals treated with a combination of sorafenib and RFA, whereas the size reduction seen in the RFA-only group indicated an RFA-mediated distant suppression of tumour growth. Growth factor measurement revealed transiently decreased EGF levels after RFA (P=0.008), whereas sorafenib treatment decreased HGF levels (P=0.001). MVD (microvessel density) was reduced by sorafenib (P=0.002) despite increased VEGF levels (P≤0.0001). The immune parameters revealed augmented T-cells and IL-10 (interleukin 10) levels in all three treatment groups; sorafenib additionally increased macrophage numbers (P≤0.0001). RFA and sorafenib alone resulted in significant volume reduction of the non-RFA-targeted tumour; this effect was enhanced when both modalities were combined.

Different roles of hepatic hypothermic ischemia and ischemic preconditioning in chemically induced hepatocarcinogenesis in rats.

BACKGROUND: Hepatic ischemia-reperfusion (IR) injury, an unfavorable complication of hepatectomy, could be prevented by hypothermic ischemia and ischemic preconditioning (IPC). However, the effects of these two approaches on hepatocarcinogenesis have not been examined. The aim of the study was to investigate roles of hypothermic ischemia and IPC in a chemically induced rat liver tumor model. METHODS: Twenty-four Sprague-Dawley rats were treated with diethylnitrosamine and phenobarbital to induce hepatocellular carcinoma. Rats underwent hepatic ischemic injury, hypothermic ischemia, and IPC. Twenty-eight-wk-old rats were sacrificed to evaluate the morbidity and growth of liver tumor. Cytokines were measured at the protein and messenger RNA level. RESULTS: IR injury significantly promoted liver tumor development. Intriguingly, hypothermic ischemia, but not IPC, delayed liver carcinogenesis, although both of them suppressed the hepatic IR injury. IPC-treated rats showed elevated interleukin (IL)-6 concentration in the serum and messenger RNA expression in liver. In addition, higher levels of IL-6 activated signal transducer and activator of transcription 3 in the liver of IPC-treated rats. The hepatic expression of target genes of signal transducer and activator of transcription 3 signaling, cyclin D1, c-myc, c-fos, and c-jun, all of which might participate in tumor progression, increased in IPC group, compared with that of IR group. CONCLUSIONS: These data indicated hypothermic ischemia could ameliorate both IR injury and liver tumor development. However, IPC, another effective method to prevent hepatic IR injury, might exacerbate liver tumor growth. The elevated level of IL-6 was one of the reasons for the different effects of hypothermic ischemia and IPC on hepatocarcinogenesis in rats.

Ultrasound-based tumor movement compensation during navigated laparoscopic liver interventions.

BACKGROUND: Image-guided navigation aims to provide better orientation and accuracy in laparoscopic interventions. However, the ability of the navigation system to reflect anatomical changes and maintain high accuracy during the procedure is crucial. This is particularly challenging in soft organs such as the liver, where surgical manipulation causes significant tumor movements. We propose a fast approach to obtain an accurate estimation of the tumor position throughout the procedure. METHODS: Initially, a three-dimensional (3D) ultrasound image is reconstructed and the tumor is segmented. During surgery, the position of the tumor is updated based on newly acquired tracked ultrasound images. The initial segmentation of the tumor is used to automatically detect the tumor and update its position in the navigation system. Two experiments were conducted. First, a controlled phantom motion using a robot was performed to validate the tracking accuracy. Second, a needle navigation scenario based on pseudotumors injected into ex vivo porcine liver was studied. RESULT: In the robot-based evaluation, the approach estimated the target location with an accuracy of 0.4 ± 0.3 mm. The mean navigation error in the needle experiment was 1.2 ± 0.6 mm, and the algorithm compensated for tumor shifts up to 38 mm in an average time of 1 s. CONCLUSION: We demonstrated a navigation approach based on tracked laparoscopic ultrasound (LUS), and focused on the neighborhood of the tumor. Our experimental results indicate that this approach can be used to quickly and accurately compensate for tumor movements caused by surgical manipulation during laparoscopic interventions. The proposed approach has the advantage of being based on the routinely used LUS; however, it upgrades its functionality to estimate the tumor position in 3D. Hence, the approach is repeatable throughout surgery, and enables high navigation accuracy to be maintained.

Lack of healing reaction in the cancer wound.

Surgical wounds in cancer patients have a relatively high dehiscence rate. Although cancer resections are performed so as to include macroscopically non-involved tissues, some cancer cells can be present in the line of transection or surrounding tissues (R1 and R2 resections). The local healing process may facilitate proliferation of these localized cancer cells, and the high cytokine concentration within the healing wound may also attract cancer cells from distant sites to migrate into the wound area. The question arises how the tumor environment influences the wound healing process. The aim of the study was to monitor and compare, using immunohistochemical methods, the healing process of an incision wound performed through a metastatic liver tumor of colon cancer with the healing of a normal liver incision wound. The experiments were carried out on a CC531 colon cancer rat model. We observed impaired healing of cancer wounds at all stages of wound healing. Significantly fewer mononuclear cells infiltrated the cancer than the normal liver wounds. There were no significant differences in the phenotypes of infiltrating mononuclear cells. BrdU incorporation showed rapid proliferation of cancer but not infiltrating cells or fibroblasts in the cancer wounds. We observed no connective tissue formation and poor collagen deposition in cancer wounds. Additionally, cancer wounds were significantly deprived of newly formed vessels. We confirmed that the impaired migration and proliferation of inflammatory cells in cancer wounds and poor scar tissue formation contribute to impaired healing of cancer 'contaminated' wounds.

Plk4 haploinsufficiency causes mitotic infidelity and carcinogenesis.

The polo-like kinase Plk4 (also called Sak) is required for late mitotic progression, cell survival and postgastrulation embryonic development. Here we identified a phenotype resulting from Plk4 haploinsufficiency in Plk4 heterozygous cells and mice. Plk4+/- embryonic fibroblasts had increased centrosomal amplification, multipolar spindle formation and aneuploidy compared with wild-type cells. The incidence of spontaneous liver and lung cancers was approximately 15 times high in elderly Plk4+/- mice than in Plk4+/+ littermates. Using the in vivo model of partial hepatectomy to induce synchronous cell cycle entry, we determined that the precise regulation of cyclins D1, E and B1 and of Cdk1 was impaired in Plk4+/- regenerating liver, and p53 activation and p21 and BubR1 expression were suppressed. These defects were associated with progressive cell cycle delays, increased spindle irregularities and accelerated hepatocellular carcinogenesis in Plk4+/- mice. Loss of heterozygosity occurs frequently (approximately 60%) at polymorphic markers adjacent to the PLK4 locus in human hepatoma. Reduced Plk4 gene dosage increases the probability of mitotic errors and cancer development.

Hepatic arterial infusion of temsirolimus inhibits tumor growth of colorectal rat liver metastases even after a growth stimulating procedure like liver resection.

BACKGROUND: Hepatic arterial infusion (HAI) of specific anti-tumor drugs can be more effective compared with systemic drug application. Herein, we studied whether HAI of temsirolimus is effective to inhibit tumor growth of colorectal liver metastases after liver resection. MATERIALS AND METHODS: Twenty-four Wistar Albino Glaxo from Rijswijk (WAG/Rij) rats were randomized to four groups and underwent subcapsular implantation of CC531 colorectal cancer cells in the left liver lobe. In two groups, a 70% liver resection (Phx) was performed simultaneously. After 10 d, animals received either a HAI of temsirolimus (CCI-779) or saline solution (controls). Tumor growth was determined on d 10 and 13 using three-dimensional ultrasound. On d 13, tumor tissue was removed for histologic and immunohistochemical analysis. RESULTS: Sham controls revealed a tumor growth of ∼40% from d 10 to d 13. HAI of temsirolimus completely inhibited this tumor growth. Controls with Phx showed a tumor growth of >60%. In contrast, HAI of temsirolimus in Phx animals did not only inhibit tumor growth but was even capable of decreasing the tumor size by ∼8%. Immunohistochemical analysis of the tumors showed a decreased proliferation rate and an increased cleaved caspase-3 activity, which was associated with a significant reduction of platelet endothelial cell adhesion molecule (PECAM)-1-positive cells after HAI of temsirolimus. CONCLUSIONS: HAI of temsirolimus inhibits tumor growth of CC531 colorectal liver metastases even if a growth-stimulating procedure like Phx is performed. Inhibition of tumor growth is provided by a decrease of tumor vascularization associated with an inhibition of tumor cell proliferation and an induction of tumor cell apoptosis.

Ultrasound-guided percutaneous laser and ethanol ablation of rabbit VX2 liver tumors.

BACKGROUND: Only a small percentage of patients with hepatocellular carcinoma (HCC) may benefit out of surgical resection. Thus, lots of these patients are in need of local control, such as percutaneous ethanol injection (PEI), percutaneous laser ablation (PLA), or radiofrequency thermal ablation (RF). PURPOSE: To investigate the effects of ultrasound-guided PLA combined with PEI on rabbit VX2 liver tumors, using conventional gray-scale ultrasonography (US), color/power Doppler (CD/PD)US, contrast-enhanced (CE) US, and histologic examination. MATERIAL AND METHODS: VX2 tumors were implanted in the livers of 80 rabbits. Fourteen days after implantation, animals were randomly separated into four groups of 20 rabbits. Treatment of the four groups was with: (i) PLA; (ii) PEI; (iii) combined therapy of PLA immediately followed by PEI; and (iv) combined therapy of PEI immediately followed by PLA. Conventional gray-scale US, CD US, PD US, and CE US were performed before and after ablation. The effects on ablated areas were assessed by histologic examination. RESULTS: Conventional gray-scale US showed a clear boundary around the ablated area in groups 1, 3, and 4. An isoechoic treated region with an irregular boundary was seen in group 2. On CE US, coagulated areas demonstrated a perfusion defect. Both conventional gray-scale US and CE US showed that the ablated volume in group 4 was larger than that in groups 1, 2, and 3. CD US and PD US demonstrated residual tumor in the periphery of ablated areas in groups 1 and 2, but not in groups 3 and 4. CE US demonstrated no residual tumor in group 4, unlike in groups 1, 2, and 3. Examination of treated tumors demonstrated necrosis in the ablated zones and increasing surrounding fibrous bands in the four treatment groups. Residual viable tissue in group 4 was less than that in groups 1, 2, and 3. CONCLUSION: Combined therapy of PEI immediately followed by PLA can coagulate significantly larger volumes of tumor and reduce residual tumor.

Sorafenib suppresses the rapid progress of hepatocellular carcinoma after insufficient radiofrequency ablation therapy: an experiment in vivo.

BACKGROUND: Radiofrequency ablation (RFA) is a widely applied treatment for hepatocellular carcinoma (HCC), but insufficient RFA can promote rapid progression of the residual tumor through the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGFA) pathway. Although sorafenib has been successfully applied to advanced HCC, the use of sorafenib in residual tumor cells after RFA has rarely been tested. PURPOSE: To evaluate the potential role of sorafenib as an adjunct to RFA to reduce the recurrence rate after insufficient RFA. MATERIAL AND METHODS: Xenograft tumors of SMMC 7721 were created by subcutaneously inoculating nude mice with hepatoma cells (5 × 10(6) cells per mouse). Fourteen days after inoculation, all mice were divided into three groups (control group [sham puncture], RFA group, and RFA combined with sorafenib treatment group) with six mice in each group. Each group was given a different treatment procedure. After treatment, the volume of the tumors was calculated from the resected specimens. The mRNA and protein expression of HIF-1α and VEGFA was quantified by real-time PCR and immunohistochemistry analysis. The micro-vessel density (MVD) was determined by CD34 immunohistochemistry. RESULTS: Real-time PCR and immunohistochemistry analysis showed that, compared to the RFA group, HIF-1α and VEGFA expression were significantly decreased in the group that received RFA combined with sorafenib treatment (P < 0.05). By comparing the control group with the RFA group, we found that insufficient RFA promoted HIF-1α and VEGFA expression (P < 0.05). Similar results were obtained for MVD expression. Additionally, the combination of RFA with sorafenib therapy resulted in a synergistic reduction in tumor growth compared to insufficient RFA and sham puncture (P < 0.05). CONCLUSION: Sorafenib was able to inhibit the expression of HIF-1α and VEGFA, and sorafenib was able to increase time to recurrence when used as an adjunct to RFA.