Pharmacokinetics of Irinotecan, Oxaliplatin and 5-Fluorouracil During Hepatic Artery Chronomodulated Infusion: A Translational European OPTILIV Study

The combination of hepatic artery infusion (HAI) of irinotecan, 5-fluorouracil and oxaliplatin with intravenous cetuximab has safely achieved prolonged survival in colorectal cancer patients with extensive liver metastases and prior treatment. Systemic exposure to the drugs or their main metabolites was determined during the first course of chronomodulated triplet HAI in 11 patients and related to toxicities after one or three courses. Consistent trends were found between the area under the plasma concentration-time curve (AUC) values of irinotecan, 7-ethyl-10-hydroxycamptothecin (SN38; a bioactive metabolite), total oxaliplatin and platinum ultrafiltrate (P-UF), on the one hand, and subsequent leukopenia severity, on the other hand. Moreover, the maximum plasma concentration (C _max) and the AUC of P-UF significantly predicted grades of diarrhoea (p = 0.004 and 0.017, respectively) and anaemia (p = 0.001 and 0.008, respectively) after the first course. Systemic drug exposure helps explain both the adverse events and the low rate of extrahepatic progression-a usual drawback of HAI chemotherapy-thus supporting upfront testing of the regimen. Systems optimization of chronomodulated HAI delivery could further reduce adverse events.

Effects of Melatonin, Aluminum Oxide, and Polymethylsiloxane Complex on the Expression of LYVE-1 in the Liver of Mice with Obesity and Type 2 Diabetes Mellitus

The effects of melatonin, aluminum oxide, and polymethylsiloxane complex on the expression of LYVE-1 (lymphatic vessel endothelial hyaluronan receptor) in the liver were studied in db/db mice with experimental obesity and type 2 diabetes mellitus. The complex or placebo was administered daily by gavage from week 8 to week 16 of life. The animals receiving the complex exhibited enhanced, in comparison with the placebo group, immunohistochemical LYVE-1+ staining of endothelial cells in sinusoids. Enhanced expression of LYVE-1 was associated with less pronounced dilatation of interlobular arteries, veins, and lymphatic vessels. Thee findings suggest a protective effect of the complex towards structural changes in the liver of mice with obesity and type 2 diabetes.

Saturable Hepatic Extraction of Gemcitabine Involves Biphasic Uptake Mediated by Nucleoside Transporters Equilibrative Nucleoside Transporter 1 and 2

Hepatic arterial infusion (HAI) chemotherapy with gemcitabine (GEM) is expected to be more effective and safer method to treat hepatic metastasis of pancreatic cancer compared with intravenous administration, because it affords higher tumor exposure with lower systemic exposure. Thus, a key issue for dose selection is the saturability of hepatic uptake of GEM. Therefore, we investigated GEM uptake in rat and human isolated hepatocytes. Hepatic GEM uptake involved high- and low-affinity saturable components with Km values of micromolar and millimolar order, respectively. The uptake was inhibited concentration dependently by S-(4-nitrobenzyl)-6-thioinosine (NBMPR) and was sodium-ion-independent, suggesting a contribution of equilibrative nucleoside transporters (ENTs). The concentration dependence of uptake in the presence of 0.1 μM NBMPR showed a single low-affinity binding site. Therefore, the high- and low-affinity sites correspond to ENT1 and ENT2, respectively. Our results indicate hepatic extraction of GEM is predominantly mediated by the low-affinity site (hENT2), and at clinically relevant hepatic concentrations of GEM, hENT2-mediated uptake would not be completely saturated. This is critical for HAI, because saturation of hepatic uptake would result in a marked increase of GEM concentration in the peripheral circulation, abrogating the advantage of HAI over intravenous administration in terms of severe adverse events.

Effects of Institut Georges Lopez-1 and Celsior preservation solutions on liver graft injury

AIM: To compare Institut Georges Lopez (IGL-1) and Celsior preservation solutions for hepatic endothelium relaxation and liver cold ischemia reperfusion injury (IRI).

METHODS: Two experimental models were used. In the first one, acetylcholine-induced endothelium-dependent relaxation (EDR) was measured in isolated ring preparations of rat hepatic arteries preserved or not in IGL-1 or Celsior solutions (24 h at 4 °C). To determine nitric oxide (NO) and cyclooxygenase EDR, hepatic arteries were incubated with L-NG-nitroarginine methyl ester (L-NAME), an inhibitor of endothelium nitric oxide synthase (eNOS), or with L-NAME plus indomethacin, an inhibitor of cyclooxygenase. In the second experiment, rat livers were cold-stored in IGL-1 or Celsior solutions for 24 h at 4 °C and then perfused “ex vivo” for 2 h at 37 °C. Liver injury was assessed by transaminase measurements, liver function by bile production and bromosulfophthalein clearance, oxidative stress by malondialdehyde levels and catalase activity and alterations in cell signaling pathways by pAkt, pAMPK, eNOS and MAPKs proteins level.

RESULTS: After cold storage for 24 h with either Celsior or IGL-1, EDR was only slightly altered. In freshly isolated arteries, EDR was exclusively mediated by NO. However, cold-stored arteries showed NO- and COX-dependent relaxation. The decrease in NO-dependent relaxation after cold storage was significantly more marked with Celsior. The second study indicated that IGL-1 solution obtained better liver preservation and protection against IRI than Celsior. Liver injury was reduced, function was improved and there was less oxidative stress. IGL-1 solution activated Akt and AMPK, which was concomitant with increased eNOS expression and nitrite/nitrate levels. Furthermore, MAPKs kinases were regulated in livers preserved with IGL-1 solution since reductions in p-p38, p-ERK and p-JNK protein levels were observed.

CONCLUSION: IGL-1 solution preserved NO-dependent relaxation better than Celsior storage solution and enhanced liver graft preservation.

Warm ischemic injury is reflected in the release of injury markers during cold preservation of the human liver

BACKGROUND

Liver transplantation plays a pivotal role in the treatment of patients with end-stage liver disease. Despite excellent outcomes, the field is strained by a severe shortage of viable liver grafts. To meet high demands, attempts are made to increase the use of suboptimal livers by both pretransplant recovery and assessment of donor livers. Here we aim to assess hepatic injury in the measurement of routine markers in the post-ischemic flush effluent of discarded human liver with a wide warm ischemic range.

METHODS

Six human livers discarded for transplantation with variable warm and cold ischemia times were flushed at the end of preservation. The liver grafts were flushed with NaCl or Lactated Ringer's, 2 L through the portal vein and 1 L through the hepatic artery. The vena caval effluent was sampled and analyzed for biochemical markers of injury; lactate dehydrogenase (LDH), alanine transaminase (ALT), and alkaline phosphatase (ALP). Liver tissue biopsies were analyzed for ATP content and histologically (H&E) examined.

RESULTS

The duration of warm ischemia in the six livers correlated significantly to the concentration of LDH, ALT, and ALP in the effluent from the portal vein flush. No correlation was found with cold ischemia time. Tissue ATP content at the end of preservation correlated very strongly with the concentration of ALP in the arterial effluent (P<0.0007, R2 = 0.96).

CONCLUSION

Biochemical injury markers released during the cold preservation period were reflective of the duration of warm ischemic injury sustained prior to release of the markers, as well as the hepatic energy status. As such, assessment of the flush effluent at the end of cold preservation may be a useful tool in evaluating suboptimal livers prior to transplantation, particularly in situations with undeterminable ischemic durations.

[Correlation analysis of liver function and blood flow in children with chronic cholecystocholangitis]

Presented correlation relationship between the functional state of the liver and arterial blood flow in children with chronic cholecystocholangitis. Found increases in the number of pigment and enzyme metabolism of liver, which directly depends on the slowing of blood flow in the basin of the hepatic artery. Is proved the inverse relationship growth of angular indices of internal blood flow in the hepatic artery on the lowering proteins.

Comparison of endothelin receptors in normal versus cirrhotic human liver and in the liver from endothelial cell-specific ETB knockout mice

AIMS

Endothelin (ET) antagonists show promise in animal models of cirrhosis and portal hypertension. The aim was to pharmacologically characterise the expression of endothelin receptors in human liver, hepatic artery and portal vein.

MAIN METHODS

Immunofluorescence staining, receptor autoradiography and competition binding assays were used to localise and quantify ET receptors on hepatic parenchyma, hepatic artery and portal vein in human cirrhotic or normal liver. Additional experiments were performed to determine the affinity and selectivity of ET antagonists for liver ET endothelin receptors. An endothelial cell ET(B) knockout murine model was used to examine the function of sinusoid endothelial ET(B) receptors.

KEY FINDINGS

ET(B) receptors predominated in normal human liver and displayed the highest ratio (ET(B):ET(A) 63:47) compared with other peripheral tissues. In two patients examined, liver ET(B) expression was up-regulated in cirrhosis (ET(B):ET(A) 83:17). Both sub-types localised to the media of normal portal vein but ET(B) receptors were downregulated fivefold in the media of cirrhotic portal vein. Sinusoid diameter was fourfold smaller in endothelial cell ET(B) knockout mice. The liver morphology of ET(B) knockout mice was markedly different to normal murine liver, with loss of the wide spread sinusoidal pattern. In the knockout mice, sinusoids were reduced in both number and absolute diameter, while large intrahepatic veins were congested with red blood cells.

SIGNIFICANCE

These data support a role for the ET system in cirrhosis of the liver and suggest that endothelial ET(B) blockade may cause sinusoidal constriction which may contribute to hepatotoxicity associated with some endothelin antagonists.

Evaluation of adeno-associated viral vectors for liver-directed gene transfer in dogs

This study evaluated six adeno-associated viral (AAV) vectors expressing green fluorescent protein (GFP) from the liver-specific thyroid hormone-binding globulin (TBG) promoter made with novel capsids in canine liver-directed gene transfer. Studies in 1.5-month-old dogs, which were administered vector through a peripheral vein, showed that AAV8 capsid vectors had the most favorable performance profiles. Interestingly, the absolute levels of hepatocyte transduction achieved with AAV8 were lower in dogs compared with what had been achieved in mice and nonhuman primates. Additional studies were performed with AAV8 delivered into the hepatic artery in adult dogs, with higher doses of vector used to assess potential dose-limiting toxicities. These studies showed good transduction on day 7 in one dog that apparently was lost by day 28 in another dog through the generation of GFP-specific T cells. Each adult dog was carefully monitored for any hemodynamic changes associated with vector infusion. Both animals demonstrated mild to moderate hypotension and bradycardia, which appeared to be anesthesia-related, making it difficult to evaluate contributions of the vector.

Optimization of single injection liver arterial phase gadolinium enhanced MRI using bolus track real-time imaging

PURPOSE

To measure contrast agent enhancement kinetics in the liver and to further evaluate and develop an optimized gadolinium enhanced MRI using a single injection real-time bolus-tracking method for reproducible imaging of the transient arterial-phase.

MATERIALS AND METHODS

A total of 18 subjects with hypervascular liver lesions were imaged with four dimensional (4D) perfusion scans to measure time-to-peak (TTP) delays of arterial (aorta-celiac axis), liver parenchyma, liver lesion, portal, and hepatic veins. Time delays were calculated from the TTP-aorta signal, and then related to the gradient echo (GRE) k-space acquisition design, to determine optimized timing for real-time bolus-track triggering methodology. As another measure of significance, 200 clinical patients were imaged with 3D-GRE using either a fixed time-interval or by individualized arterial bolus real-time triggering. Bolus TTP-aorta was calculated and arterial-phase acquisitions were compared for accuracy and reproducibility using specific vascular enhancement indicators.

RESULTS

The mean bolus transit-time to peak-lesion contrast was 8.1 ± 2.7 seconds following arterial detection, compared to 32.1 ± 5.4 seconds from contrast injection, representing a 62.1% reduction in the time-variability among subjects (N = 18). The real-time bolus-triggered technique more consistently captured the targeted arterial phase (94%), compared to the fixed timing technique (73%), representing an expected improvement of timing accuracy in 28% of patients (P = 0.0001389).

CONCLUSION

Our results show detailed timing window analysis required for optimized arterial real-time bolus-triggering acquisition of transient arterial phase features of liver lesions, with optimized arterial triggering expected to improve reproducibility in a significant number of patients.

Liver fat content in type 2 diabetes: relationship with hepatic perfusion and substrate metabolism

OBJECTIVE

Hepatic steatosis is common in type 2 diabetes. It is causally linked to the features of the metabolic syndrome, liver cirrhosis, and cardiovascular disease. Experimental data have indicated that increased liver fat may impair hepatic perfusion and metabolism. The aim of the current study was to assess hepatic parenchymal perfusion, together with glucose and fatty acid metabolism, in relation to hepatic triglyceride content.

RESEARCH DESIGN AND METHODS

Fifty-nine men with well controlled type 2 diabetes and 18 age-matched healthy normoglycemic men were studied using positron emission tomography to assess hepatic tissue perfusion, insulin-stimulated glucose, and fasting fatty acid metabolism, respectively, in relation to hepatic triglyceride content, quantified by proton magnetic resonance spectroscopy. Patients were divided into two groups with hepatic triglyceride content below (type 2 diabetes-low) or above (type 2 diabetes-high) the median of 8.6%.

RESULTS

Type 2 diabetes-high patients had the highest BMI and A1C and lowest whole-body insulin sensitivity (ANOVA, all P < 0.001). Compared with control subjects and type 2 diabetes-low patients, type 2 diabetes-high patients had the lowest hepatic parenchymal perfusion (P = 0.004) and insulin-stimulated hepatic glucose uptake (P = 0.013). The observed decrease in hepatic fatty acid influx rate constant, however, only reached borderline significance (P = 0.088). In type 2 diabetic patients, hepatic parenchymal perfusion (r = -0.360, P = 0.007) and hepatic fatty acid influx rate constant (r = -0.407, P = 0.007) correlated inversely with hepatic triglyceride content. In a pooled analysis, hepatic fat correlated with hepatic glucose uptake (r = -0.329, P = 0.004).

CONCLUSIONS

In conclusion, type 2 diabetic patients with increased hepatic triglyceride content showed decreased hepatic parenchymal perfusion and hepatic insulin mediated glucose uptake, suggesting a potential modulating effect of hepatic fat on hepatic physiology.

Tracer input for kinetic modelling of liver physiology determined without sampling portal venous blood in pigs

Purpose

Quantification of hepatic tracer kinetics by PET requires measurement of tracer input from the hepatic artery (HA) and portal vein (PV). We wished to develop a method for estimating dual tracer input without the necessity to sample PV blood.

Methods

Pigs weighing 40 kg were given bolus doses of C¹⁵O (CO), 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG), [¹¹C]-methylglucose (MG), 2-[¹⁸F]fluoro-2-deoxy-D-galactose (FDGal) or H₂¹⁵O (H₂O). Tracer concentration 3-min time courses were measured in the femoral artery and PV by blood sampling. Blood flow was measured in the HA and PV using flow-meters. A model for transfer of tracer through the splanchnic circulation was used to estimate values of a tracer-specific model parameter β. Tracer-specific mean values of β were used to estimate tracer concentration time courses in the PV from the measured arterial concentration. A model-derived dual-input was calculated using the mean HA flow fraction (0.25) and validated by comparison of the use of the measured dual-input and a kinetic model with a fixed ”true” K₁^true, i.e. clearance of tracer from blood to liver cells.

Results

The rank order of the means of β was CO < FDG ≈ MG < FDGal < H₂O, reflecting their different splanchnic mean transit times. Estimated K₁^est was not significantly different from “true” K₁^true.

Conclusion

The hepatic dual tracer input, which is of great importance for the assessment of processes such as transfer across the plasma-hepatocyte membrane or hepatic blood perfusion, can be well approximated in pigs without the necessity to sample PV blood and measure hepatic blood flow; only arterial blood sampling is needed.

Definition of contrast enhancement phases of the liver using a perfluoro-based microbubble agent, perflubutane microbubbles

To define the contrast enhancement phases in the liver with perflubutane microbubbles, the liver enhancement time-intensity curves were investigated in 14 healthy volunteers. The agent was injected intravenously as a bolus and the liver was imaged with an ultrasound scanner as long as 4h after the injection. Time-intensity curves from the hepatic artery, the intrahepatic portal vein, the hepatic vein and the parenchyma of the liver were obtained from the liver ultrasound images. The arrival of the agent in the hepatic artery, the portal vein and the hepatic vein were visually distinguishable and the mean arrival times were 19.2, 24.3 and 32.2 s after the injection, respectively. The signal intensity in these vessels increased rapidly after the arrival of the contrast and gradually reverted to baseline after the peak. In contrast, within 5 min after the injection, the intensity in the parenchyma increased and reached a plateau, which persisted for at least 2h. The contrast enhancement phases in the liver with perflubutane microbubbles could be defined as two major phases-a vascular phase, in which the vessels are enhanced between 15 s and 10 min after injection, and a Kupffer phase, in which the parenchyma is enhanced 10 min after injection. The vascular phase is divided into three subphases: the arterial phase (15 to 45 s after injection); the portal phase (45 s to 1 min after injection); and the vasculo-Kupffer phase (1 to 10 min after injection).

Evidence against a role for NADPH oxidase modulating hepatic vascular tone in cirrhosis

BACKGROUND & AIMS

Increased hepatic vascular resistance in cirrhosis is in part due to reduced nitric oxide (NO) bioavailability. This is related to insufficient NO synthesis from endothelial nitric oxide synthase and to enhanced NO scavenging by superoxide radicals (O(2)(-)). Nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase is an important source of O(2)(-) that increases vascular tone in different cardiovascular disorders. Thus, our aims were to study the molecular and biochemical state of NADPH-oxidase in cirrhotic livers and to investigate its possible role in modulating hepatic vascular tone in cirrhosis.

METHODS

NADPH-oxidase expression and enzymatic activity were determined in control (n = 8) and CCl(4)-cirrhotic (n = 8) rat livers. Additional control (n = 6) and CCl(4)-cirrhotic (n = 10) rats were treated with apocynin (a selective NADPH-oxidase inhibitor) or its vehicle. Mean arterial pressure, portal pressure, and superior mesenteric arterial blood flow were measured in vivo. Moreover, hepatic endothelial function was evaluated in isolated and perfused rat livers by dose-response curves to acetylcholine. In addition, in 6 control and 6 cirrhotic human livers NADPH-oxidase activity and expression were evaluated.

RESULTS

Rat cirrhotic livers had no increased NADPH-oxidase protein expression or activity in relation to control livers. NADPH-oxidase inhibition did not modify splanchnic or systemic hemodynamics in control or cirrhotic rats and did not improve the impaired endothelial-dependent vasodilatory response to acetylcholine of cirrhotic livers. Human cirrhotic livers also did not exhibit increased NADPH-oxidase expression or activity.

CONCLUSIONS

Our study shows that NADPH-oxidase activity is decreased in the cirrhotic livers and therefore cannot explain increased hepatic O(2)(-), endothelial dysfunction, and increased vascular tone in cirrhotic livers.

High volume hydrodynamic injection of plasmid DNA via the hepatic artery results in a high level of gene expression in rat hepatocellular carcinoma induced by diethylnitrosamine

BACKGROUND

Hydrodynamic injection of naked plasmid DNA (pDNA) via the tail vein is a safe and effective method of gene transfer to the liver. However, successful gene transfer has yet to be shown for hepatocellular carcinoma (HCC); therefore, we investigated the feasibility and efficacy of hydrodynamic injection via the tail vein and hepatic artery in a diethylnitrosamine (DEN)-induced HCC model in rats.

METHODS

HCC was induced in Sprague-Dawley rats by 100 ppm DEN in drinking water. pCMV-SPORT-beta-galactosidase (beta-gal, 400 microg) was injected (i) via the tail vein in a volume of 0.1 ml/g in 30 s or (ii) via the hepatic artery in a volume of 5 or 10 ml at 1 ml/s, either with or without temporary occlusion of the inferior vena cava (IVC) and portal vein (PV). The liver was harvested 24 h after administration, and beta-gal expression was evaluated with X-gal staining and measurement of enzymatic activity in tissue homogenates.

RESULTS

Hydrodynamic injection via the tail vein achieved transgene expression only in non-cancerous tissue (tumor: 0.16 +/- 0.04%, non-tumor: 5.07 +/- 1.66%). Hydrodynamic injection via the hepatic artery was tolerated, but failed to produce efficient transgene expression in tumor and non-tumor cells. On the other hand, concomitant use of temporary IVC/PV occlusion with hydrodynamic injection via the hepatic artery dramatically increased transgene expression in cancer cells, but tumor-selective gene transfer was not achieved with this procedure (tumor: 7.38 +/- 3.66%, non-tumor: 7.77 +/- 1.06%).

CONCLUSIONS

High-volume hydrodynamic injection of a pDNA solution via the hepatic artery with IVC/PV occlusion achieved a high level of gene expression in a HCC rat model. This gene transfer technique may have potential in clinical gene therapy for HCC.

Patient-specific dosimetry calculations using mathematic models of different anatomic sizes during therapy with 111In-DTPA-D-Phe1-octreotide infusions after catheterization of the hepatic artery

The aim of the study was to provide dosimetric data on intrahepatic (111)In-diethylenetriaminepentaacetic acid (DTPA)-D-Phe(1)-octreotide therapy for neuroendocrine tumors with overexpression of somatostatin receptors.

METHODS

A dosimetric protocol was designed to estimate the absorbed dose to the tumor and healthy tissue in a course of 48 treatments for 12 patients, who received a mean activity of 5.4 +/- 1.7 GBq per session. The patient-specific dosimetry calculations, based on quantitative biplanar whole-body scintigrams, were performed using a Monte Carlo simulation program for 3 male and 3 female mathematic models of different anatomic sizes. Thirty minutes and 2, 6, 24, and 48 h after the radionuclide infusion, blood-sample data were collected for estimation of the red marrow radiation burden.

RESULTS

The mean absorbed doses per administered activity (mGy/MBq) by the critical organs liver, spleen, kidneys, bladder wall, and bone marrow were 0.14 +/- 0.04, 1.4 +/- 0.6, 0.41 +/- 0.08, 0.094 +/- 0.013, and (3.5 +/- 0.8) x 10(-3), respectively; the tumor absorbed dose ranged from 2.2 to 19.6 mGy/MBq, strongly depending on the lesion size and tissue type.

CONCLUSION

The results of the present study quantitatively confirm the therapeutic efficacy of transhepatic administration; the tumor-to-healthy-tissue uptake ratio was enhanced, compared with the results after antecubital infusions. Planning of treatment was also optimized by use of the patient-specific dosimetric protocol.

[Pharmacokinetics of doxorubicin alginate microspheres and evaluation of its hepatic arterial embolization in vivo]

AIM

To investigate the pharmacokinetics of doxorubicin alginate microspheres (DOX-AM) in vivo after hepatic arterial embolization.

METHODS

China miniature pigs were chosen as the experimental animals. Transcatheter hepatic arterial chemoembolization (TACE) with DOX-AM (experimental group), lipiodol and DOX (DOX-lipiodol, control group 1), and infusion with DOX (control group 2) were performed after angiography and superselection of an intrahepatic branch of hepatic artery. After chemoembolization or infusion, the blood was collected at different time intervals. Drug concentration in plasma was measured by HLPC and the parameters of pharmacokinetics were calculated.

RESULTS

The values of T1/2, AUC, Cmax, and MRT of the DOX-AM were significantly different from those of control group 1 and control group 2. After embolization, the DOX-AM embolized in the vessel and still retained there at 8 weeks. The digital subtraction arteriography (DSA) and computerized tomography (CT) showed the reliable embolization results. The histological examination indicated that the liver damnifications were changed transitorily in all groups (P < 0.05) and were recovered within two weeks. The liver damnifications increased in following order: DOX < DOX-AM < DOX-lipiodol.

CONCLUSION

DOX-AM showed definite property of delayed release of drug in liver, and increased the retention time and concentration of DOX after embolization in vivo.

Expression of the interferon-induced Mx proteins in biliary atresia

Biliary atresia (BA) is a rare disease of the newborn for which the Kasai procedure is curative only for a few of the patients. The dilemma is that all therapeutic attempts to cure the disease are symptomatic because the etiology is still unclear. One theory suggests a progressive inflammatory process, possibly induced by a viral infection. The aim of the present study was to investigate the activity of type I interferons (IFNs) in the livers of patients with BA. Mx proteins, which mediate an early innate immune response, are a very sensitive marker for type I IFN activity (eg, to viral infection). Liver biopsies were taken during the Kasai procedure from 13 newborns with BA who were serologically negative for hepatotropic viruses. Age-matched controls originated from 7 patients with neonatal cholestasis (eg, inspissated bile syndrome), 3 aborted fetuses, and a 10-year-old child. The immunostaining procedure (alkaline phosphatase anti-alkaline phosphatase) was performed with Mx-specific monoclonal antibody. Immunostaining for Mx proteins was positive in the hepatocytes of all newborns with BA, whereas the intrahepatic bile ducts were positive in all but one. In the control group, 8 of 11 liver samples were Mx-negative. This is the first study dealing with the detection of type I IFN activity in the liver of patients with BA. This observation supports the etiologic consideration of type I IFN-mediated immune response. Although positive findings of viruses in patients with BA are still inconsistent, the present study retraces the progressive inflammatory process in BA one more step toward its beginning.

[11C]palmitate kinetics across the splanchnic bed in arterial, portal and hepatic venous plasma during fasting and euglycemic hyperinsulinemia

PURPOSE

The liver is fundamental in regulating lipid metabolism, and it supplies fatty acids (FA) to the rest of the body in the form of triglycerides (TG); the time-related relevance of this process is incompletely defined. The aim of the study was to investigate the appearance of labeled TG in the hepatic vascular bed after [11C]palmitate injection during fasting and insulin stimulation.

METHODS

Plasma [11C]palmitate kinetics in arterial, portal and hepatic venous lipid fractions was studied in eight anesthetized pigs during fasting or euglycemic hyperinsulinemia. Plasma analyses were conducted at 10 and 40 min after tracer injection. Corresponding liver positron emission tomography (PET) images were acquired for the semiquantitative determination of hepatic FA uptake.

RESULTS

At 10 min, plasma levels of unchanged [11C]palmitate were lower in hyperinsulinemic than in fasting experiments in the artery and in the portal vein (P< or=.03), suggesting faster clearance. Levels of unmetabolized [11C]palmitate did not differ between portal and arterial plasma. In the fasting state, a tendency to a positive arterial and portal vs. hepatic venous gradient was observed, indicative of net hepatic [11C]palmitate extraction. Labeled TG were already detectable at 10 min (fasting vs. hyperinsulinemia, ns) and were higher in fasting than in hyperinsulinemic animals at 40 min (92+/-1% and 82+/-6% of arterial plasma radioactivity). Higher proportions of labeled TG were recovered in portal vein plasma, suggesting release by the gut. The portal and the arterial-portal vs. hepatic venous TG gradient tended to be positive. Accordingly, hepatic FA uptake was higher, but declined more rapidly during fasting than during hyperinsulinemia.

CONCLUSION

The study indicates that the redistribution of [11C]palmitate between different lipid pools occurs within the short time interval of most PET experiments and is strongly influenced by insulin. Labeled TG constitute an additional [11C]palmitate source in the modeling of PET data.

Feasibility of Blood Oxygenation Level–dependent MR Imaging to Monitor Hepatic Transcatheter Arterial Embolization in Rabbits

Blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging is a noninvasive method to assess changes in oxygen delivery to tissues. It was hypothesized that BOLD MR imaging can detect changes in rabbit VX2 liver tumor oxygenation after hepatic artery embolization with polyvinyl alcohol particles. In four discrete VX2 liver tumors, a statistically significant mean reduction in apparent transverse relaxation time was shown, from 55 milliseconds before embolization to 41 milliseconds after embolization (P < .01). This reduction corresponded to a decrease in hepatic tumor oxygenation. The use of BOLD MR imaging to monitor changes in hepatic tumor oxygenation after embolization is feasible. These functional MR imaging measurements of hypoxia may be targeted as an endpoint for therapy in future studies.

Hemodynamic and morphologic changes of peripheral hepatic vasculature in cirrhotic liver disease: A preliminary study using contrast-enhanced coded phase inversion harmonic ultrasonography

AIM: To provide the useful information for the diagnosis of liver cirrhosis by observing the morphology of peripheral hepatic vessels and the hemodynamics of microbubble arrival time in these vessels.

METHODS: Twenty-one subjects including 5 normal volunteers and 16 patients (liver cirrhosis, n=10; chronic hepatitis, n=6) were studied by contrast-enhanced coded phase inversion harmonic sonography (GE LOGIQ 9 series) using a 6-8 MHz convex-arrayed wide-band transducer. The images of peripheral hepatic artery, portal and hepatic vein were observed in real-time for about 2 min after intravenous injection of Levovist. The time when microbubbles appeared in the peripheral vessels (microbubble arrival time) was also recorded. The morphologic changes of peripheral hepatic vasculature were classified as marked, slight, and no changes based on the regularity in caliber, course, ramification, and the delineation of vessels compared to normal subjects.

RESULTS: The microbubble arrival time at peripheral artery, portal, and hepatic vein was shorter in cirrhotic patients than in chronic hepatitis patients and normal subjects. The marked, slight and no morphologic changes of peripheral hepatic vasculature found in 5 (5/6, 83.3%), 1 (1/6, 16.7%), and 0 (0/6, 0%) liver cirrhosis patients, respectively, and in 1 (1/10, 10%), 6 (6/10, 60%), and 3 (3/10, 30%) chronic hepatitis patients, respectively. There was a significant difference between the two groups (P<0.001).

CONCLUSION: Evaluation of the hemodynamics and morphology of peripheral hepatic vasculature by contrast-enhanced coded pulse inversion harmonic sonography can provide useful information for the diagnosis of liver cirrhosis.

Real-time MRI monitoring of transcatheter hepatic artery contrast agent delivery in rabbits

RATIONALE AND OBJECTIVES

We sought to test the hypothesis that transcatheter hepatic artery delivery of dilute gadolinium (Gd) in rabbits can be monitored in real-time using magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Catheters (2F) were inserted via a femoral access into the hepatic arteries of six New Zealand White rabbits under radiographic guidance. After transfer to a 1.5-T MRI scanner, 26 separate hepatic artery injections of 2 mL of 4% Gd and 14 sham injections were performed. Real-time imaging of all injections was acquired using two-dimensional projection inversion recovery-gradient echo. Films of these 40 injections, as well as 10 random repeats, were independently reviewed in a randomized, blinded fashion by two Certificate of Added Qualification-certified interventional radiologists. Observers reported (i) if Gd injection occurred and (ii) if so, the location of delivery. For each observer, we compared sensitivity/specificity for real-time visualization of contrast injection and accuracy of injection localization. Interobserver and intraobserver variability was assessed using the kappa statistic. X-ray digital subtraction angiography was the gold standard for all MRI studies.

RESULTS

Both observers had a sensitivity of 100% and a specificity of 93%. Accuracy for intrahepatic contrast delivery was 77% for both observers. Accuracy for extrahepatic delivery was 92% and 96%, respectively. Both interobserver and intraobserver agreement was outstanding.

CONCLUSIONS

In rabbits, MRI allows for accurate real-time monitoring of transcatheter hepatic artery delivery of contrast agent. Localization accuracy is higher outside the liver than within the liver. These results can be used as a baseline reference for comparing the accuracy of delivery of Gd-tagged therapies in the future.

Treatment of multi-focal colorectal carcinoma metastatic to the liver of immune-competent and syngeneic rats by hepatic artery infusion of oncolytic vesicular stomatitis virus

Viruses that replicate selectively in cancer cells hold considerable promise as novel therapeutic agents for the treatment of malignancy. We report an orthotopic model of multi-focal colorectal cancer (CRC) metastases in the livers of syngeneic and immune-competent rats, which permitted rigorous testing of oncolytic virus vectors as novel therapeutic agents through hepatic arterial infusion for efficacy and safety. Vesicular stomatitis virus (VSV) is a negative-strand RNA virus with intrinsic oncolytic specificity due to attenuated anti-viral responses in many tumors. After administration at the maximum tolerated dose, the recombinant VSV vector gained access to multi-focal hepatic CRC lesions that led to tumor-selective viral replication and oncolysis. No relevant vector-associated toxicities were noted and in particular, no damage to the hepatic parenchyma was seen. Moreover, the survival rate of vector-treated rats was significantly improved over that of animals in the control treatment group (p = 0.015). Our results demonstrate that hepatic arterial administration of oncolytic VSV is both effective and safe in an immune-competent and syngeneic rat model of multi-focal CRC liver metastasis, suggesting that it can be developed into an effective therapeutic modality in patients in the future.

Hepatic microcirculation and cholangiocyte physiopathology

BACKGROUND

The peribiliary plexus (PBP) plays a fundamental role in supporting the functions of the biliary epithelium. After common bile duct ligation (BDL) progressive PBP proliferation is demonstrated. We have, recently, demonstrated that the biliary epithelium express Vascular Endothelial Growth Factor (VEGF), both subtype -A and -B and VEGF receptors. Taking in consideration the wide extension of PBP during BDL, aim of our study is to investigate the role of VEGF in stimulating angiogenesis and also in the modulation of epithelial cells proliferation.

MATERIAL AND METHODS

Experimental studies were performed by evaluating the effects of: a) endogenous VEGF neutralization by chronic administration of anti VEGF-C antibody on cholangiocyte proliferation in BDL rats and; b) the hepatic artery ligation (HAL) immediately after BDL followed by treatment (7 days) with a recombinant of VEGF-A (administered through IP implanted minipumps) on cholangiocyte proliferative activities.

RESULTS

Both administration of antiVEGF-C antibody and HAL decreases cholangiocyte proliferation. The decrease of cholangiocyte proliferation was associated with depressed VEGF-A protein expression. The administration of rVEGF-A to BDL, hepatic artery ligated rats prevented the decrease of cholangiocyte proliferation and VEGF-A expression as compared to BDL control rats.

CONCLUSION

These data suggest that VEGF-C modulates the proliferative activities of cholangiocytes in experimental cholestasis and that circulating factors (i.e., VEGF) in the blood supply of the intra-hepatic biliary epithelium, play an important role in the balance between cholangiocyte proliferation/loss.

Continuous hepatic arterial infusion chemotherapy for liver metastasis from biliary tract and pancreatic cancers

BACKGROUND

The efficacy of intrahepatic arterial chemotherapy for liver metastasis from biliary tract or pancreatic cancer remains uncertain.

PATIENTS AND METHODS

Five patients with bilio-pancreatic liver metastasis underwent continuous hepatic arterial infusion chemotherapy. One treatment course basically consisted of a 14-day infusion period during which continuous infusions of 5-fluorouracil and intermittent bolus injections of cisplatin were given, and a subsequent 14-day intermission. After two consecutive courses, these drugs were administered bi-weekly.

RESULTS

One complete and three partial responses were observed (response rate, 80%). In responders, the responses persisted until or even after the cessation of chemotherapy. The median survival was 15 months after the start of chemotherapy. The longest survivor has been disease-free for 46 months since a liver tumour remaining despite chemotherapy was eradicated by further treatment. Toxicity was acceptable.

CONCLUSION

5-Fluorouracil and cisplatin-based continuous hepatic arterial infusion chemotherapy may serve as a promising treatment for bilio-pancreatic liver metastasis.

Preparation and biodistribution of rhenium-188 ECD/Lipiodol in rats following hepatic arterial injection

Radiolabeled Lipiodol has routinely been used in hepatoma therapy. In this article an attempt to develop a new (188)Re-ECD/Lipiodol radiopharmaceutical, in which the chelating agent ECD (ethyl cyteinate dimer), is the constituent of the known brain perfusion agent (99m)Tc-ECD, and an evaluation of its stability and biodistribution in rats with hepatic tumors is presented. First, (188)Re-ECD was prepared in a vial, followed by extraction with Lipiodol to get the final product, (188)Re-ECD/Lipiodol. The optimal labeling conditions for (188)Re-ECD were: (1) tartaric acid which is better than EDTA as a weak chelating agent; and (2) 15 mg of SnCl(2), as the reducing agent, and 5-10 mg of tartaric acid in each vial had a better labeling yield. The radiochemical purity of (188)Re-ECD/Lipiodol was more than 94%. Twenty-four male Sprague-Dawley rats with liver tumors were sacrificed at 1, 24, and 48 h (eight rats each time) after an injection of approximately 7.4 MBq of (188)Re-ECD/Lipiodol via the hepatic artery. The radioactivity in the liver tumor is significantly high following therapeutic arterial injection, and relatively low in other organs including the bone, spleen, brain, thyroid, stomach, muscle, blood, and testis throughout this study. In conclusion, the new preparation of (188)Re-ECD/Lipiodol is a candidate agent for the treatment of liver cancer.

Development of 99mTc labelled Lipiodol: biodistribution following injection into the hepatic artery of the healthy pig

BACKGROUND

We develop a method for the radiolabelling of Lipiodol with Tc, using a lipophilic complex, [99mTc-(S2CPh)(S3Ph)2], dissolved in Lipiodol (99mTc-SSS Lipiodol).

RESULTS

The labelling yield is high (96 +/- 0.8%), and the radiochemical purity satisfactory (92 +/- 2.6%). This labelling is reproducible and stable for up to 24 h in vitro. Studies carried out after injection into the hepatic artery of the healthy pig show that the biodistribution of 99mTc-SSS Lipiodol is comparable with that observed for 188Re Lipiodol.

MATERIALS AND METHODS

The 99mTc-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with 99mTc, in cold lipiodol. The radiochemical purity (RCP) of the labelling was checked immediately and at 24 h. The 99mTc-SSS lipiodol was injected into the hepatic artery of four healthy pigs for an ex-vivo biodistribution study. An autoradiographic study was performed in two cases.

CONCLUSIONS

Apart from the specific interest of a Lipiodol-bearing technetiated agent for carrying out dosimetric studies, the labelling of Lipiodol with 99mTc is a preliminary step towards the use of radiolabelling with the 188Re analogue.

Oncolysis of multifocal hepatocellular carcinoma in the rat liver by hepatic artery infusion of vesicular stomatitis virus

Hepatocellular carcinoma (HCC) is a lethal malignancy with poor prognosis and few effective treatments, as well as ever-increasing frequencies in the Western world. Viruses that replicate selectively in cancer cells hold considerable promise as novel therapeutic agents for the treatment of malignancy. Vesicular stomatitis virus (VSV) is a negative-strand RNA virus with intrinsic oncolytic specificity due to significantly attenuated antiviral responses in many tumor cells. The aim of this study was to evaluate the potential of VSV, administered via the hepatic artery, as an effective and safe therapeutic agent for treating "multifocal" HCC in the rat liver. Recombinant VSV vector expressing beta-galactosidase (rVSV-beta-gal) was generated by reverse genetics and infused into the hepatic artery of Buffalo rats bearing orthotopically implanted multifocal HCC. Access by the virus to multifocal HCC lesions in the liver, as well as the kinetic profiles of intratumoral viral replication and spread, was established by X-gal staining of liver and tumor sections. Plaque assays were also performed to determine the infectious viral yields in tumor and normal liver tissues. Pharmacotoxicology studies, including serum chemistries and proinflammatory cytokine production, as well as organ histopathology, were performed. Buffer- or vector-treated tumor-bearing rats were followed for survival and the results were analyzed by the Kaplan-Meier method and the log-rank test. Hepatic arterial infusion of rVSV-beta-gal at the maximum tolerated dose in tumor-bearing rats resulted in efficient viral transduction of multifocal HCC lesions in their livers, tumor-selective viral replication, and extensive oncolysis. Importantly, no significant vector-associated toxicities were noted and, in particular, no damage to the hepatic parenchyma was seen. Finally, survival of vector-treated rats was substantially prolonged over that of animals in the control treatment group (p < 0.028). Thus, hepatic arterial administration of VSV is both effective and safe in an orthotopic animal model of multifocal HCC. The results suggest that oncolytic VSV can be developed into an effective and safe therapeutic modality for patients with multifocal HCC in the future.

Angiopoietin-1 causes reversible degradation of the portal microcirculation in mice: implications for treatment of liver disease

In many different liver diseases, such as cirrhosis, degradation of the microcirculation, including obliteration of small portal or hepatic veins contributes to disease-associated portal hypertension. The present study demonstrates the importance of angiogenesis in the establishment of arteriovenous shunts and the accompanying changes to the venous bed. One aspect of angiogenesis involves the branching of new vessels from pre-existing ones, and the molecular mechanisms controlling it are complex and involve a coordinated effort between specific endothelial growth factors and their receptors, including the angiopoietins. We modulated the hepatic vasculature in mice by conditionally expressing angiopoietin-1 in hepatocytes. In mice exposed to angiopoietin-1 during development, arterial sprouting, enlarged arteries, marked loss of portal vein radicles, hepatic vein dilation, and suggestion of arteriovenous shunting were observed. Most importantly, these phenotypic changes were completely reversed within 14 days of turning off transgene expression. Expression of excess angiopoietin-1 beginning in adulthood did not fully recapitulate the phenotype, but did result in enlarged vessels. Our findings suggest that controlling excessive angiogenesis during liver disease may promote the restoration of the portal vein circuit and aid in the resolution of disease-associated portal hypertension.

Bioembolisation for unresectable hepatocellular carcinoma: preliminary results of a translational research study

Lack of effective treatment for surgically unresectable hepatocellular carcinoma has made this disease dismal. Although, systemic and/or locoregional chemotherapy and chemo-embolization are among the established treatment options, the results of these modalities are still far from being satisfactory. Systemic interferon administration is also used for the treatment of this disease however it has high toxicity rates. We conducted a pharmacology guided phase I/II study with the aim to explore the effect of hypoxy and interferon alpha-2a in vitro using the HepG2 Hepatoma cell line. We then translated the in-vitro results to the clinical setting and designed a treatment protocol. This schema consisted of lipiodol embolisation via a hepatic artery port in between two sets of seven loco-regional injections of IFNalpha-2a, 3 MU every other day. The in-vitro study revealed the best sequence of hypoxy and IFN as IFN-Hypoxy-IFN. Based on this finding, ten patients with HCC were treated with loco-regional IFN and lipiodolisation. Seven of them achieved partial response and the mean duration of response was 10 months. There was no Grade 4 toxicity. In conclusion, our preliminary clinical results suggest that the combined use of IFN and lipiodolisation in the optimal sequence may provide a new therapeutic option for patients with HCC.

Development and biodistribution of 188Re-SSS lipiodol following injection into the hepatic artery of healthy pigs

Although intra-arterial radiotherapy with (131)I-labelled lipiodol is a useful therapeutic approach in the treatment of hepatocellular carcinomas, various disadvantages limit its use. Here we describe the development of (188)Re-SSS lipiodol, as well as its biodistribution in the healthy pig after injection into the hepatic artery. The (188)Re-SSS lipiodol was obtained after dissolving a chelating agent, previously labelled with (188)Re, in cold lipiodol. The radiochemical purity (RCP) of the labelling was checked immediately and at 24 and 48 h. The (188)Re-SSS lipiodol was injected into the hepatic artery of six healthy pigs. They were killed 1, 24 and 48 h post injection, for ex vivo counting. An autoradiographic study was performed in three cases. (188)Re-SSS lipiodol was obtained with a yield of 87%+/-9.1%. The immediate RCP was 93%+/-3.4%. This radiolabelling was reproducible and stable at 48 h in plasma: 90.6%+/-1.5% of the activity remained in the lipiodol with an RCP of 91%+/-4%. Ex vivo counting confirmed the predominantly hepatic uptake and revealed weak lung and intestinal uptake. There was very weak urinary elimination (2.3%+/-0.5% at 48 h) and a slightly higher level of intestinal elimination (4.8%+/-1.9% at 48 h). The autoradiographic studies showed (188)Re-SSS lipiodol to be located mainly in sinusoids, like (131)I-lipiodol. By using the method described here, (188)Re-SSS lipiodol can be obtained with a very high yield and a satisfactory RCP. Its biodistribution in the healthy pig is in agreement with data published elsewhere concerning other types of radiolabelling used for lipiodol, except for the very weak urinary and intestinal elimination, which probably indicates better stability of (188)Re-SSS labelling.

Intestinal lysine metabolism is driven by the enteral availability of dietary lysine in piglets fed a bolus meal

Previous steady-state continuous-feeding studies have shown that the gut mucosa removes substantial amounts of both dietary and systemic amino acids. However, enteral nutrition is often given under non-steady-state conditions as a bolus meal, and this has been shown to influence systemic metabolism. Therefore, our aim was to quantify the relative metabolism of dietary and systemic lysine by the portal-drained viscera (PDV) under non-steady-state conditions after a single bolus meal. Five 28-day-old piglets implanted with arterial, venous, and portal catheters and with an ultrasonic portal flow probe were given an oral bolus feeding of a milk formula containing a trace quantity of intrinsically 15N-labeled soy protein and a continuous intravenous infusion of [U-13C]lysine for 8 h. Total lysine use by the PDV was maximal 1 h after the meal (891 micromol x kg(-1) x h(-1)) and was predominantly of dietary origin (89%), paralleling the enteral delivery of dietary lysine. Intestinal lysine use returned to a low level after 4 h postprandially and was derived exclusively from the arterial supply until 8 h. Cumulative systemic appearance of dietary lysine reached 44 and 80% of the ingested amount 4 and 8 h after the meal, respectively, whereas the PDV first-pass use of dietary lysine was 55 and 32% of the intake for these two periods, respectively. We conclude that the first-pass utilization rate of dietary lysine by the PDV is directly increased by the enteral lysine availability and that it is higher with a bolus than with continuous oral feeding.

Chronic hepatic artery ligation does not prevent liver from differentiating portal vs. peripheral glucose delivery

Infusion of glucose into the hepatic artery blocks the stimulatory effect of the "portal signal" on net hepatic glucose uptake (NHGU) during portal glucose delivery. We hypothesized that hepatic artery ligation (HAL) would result in enhanced NHGU during peripheral glucose infusion because the arterial glucose concentration would be perceived as lower than that in the portal vein. Fourteen dogs underwent HAL approximately 16 days before study. Conscious 42-h-fasted dogs received somatostatin, intraportal insulin, and glucagon infusions at fourfold basal and at basal rates, respectively, and peripheral glucose infusion to create hyperglycemia. After 90 min (period 1), seven dogs (HALpo) received intraportal glucose (3.8 mg. kg-1. min-1) and seven (HALpe) continued to receive only peripheral glucose for 90 min (period 2). These two groups were compared with nine non-HAL control dogs (control) treated as were HALpe. During period 2, the arterial plasma insulin concentrations (24 +/- 3, 20 +/- 1, and 24 +/- 2 microU/ml) and hepatic glucose loads (39.1 +/- 2.5, 43.8 +/- 2.9, and 37.7 +/- 3.7 mg. kg-1. min-1) were not different in HALpe, HALpo, and control, respectively. HALpo exhibited greater (P < 0.05) NHGU than HALpe and control (3.1 +/- 0.3, 2.0 +/- 0.4, and 2.0 +/- 0.1 mg. kg-1. min-1, respectively). Net hepatic carbon retention was approximately twofold greater (P < 0.05) in HALpo than in HALpe and control. NHGU and net hepatic glycogen synthesis during peripheral glucose infusion were not enhanced by HAL. Even though there exists an intrahepatic arterial reference site for the portal vein glucose concentration, the failure of HAL to result in enhanced NHGU during peripheral glucose infusion suggests the existence of one or more comparison sites outside the liver.

Portal hypertension is associated with increased mRNA levels of vasopressor G-protein-coupled receptors in human hepatic arteries

BACKGROUND

The contractile response of human splanchnic vessels to different vasoconstrictors is attenuated in cirrhosis. Functional studies indicate a cellular signalling defect upstream of the G-protein level. The aim of the present study was to analyze expression and mRNA levels of the following most relevant vasopressor receptors in the smooth musculature of human hepatic arteries: alpha1 adrenoceptor (AR) subtypes a, b and d, angiotensin II type 1 receptor (AT1), arginine vasopressin receptor type 1a (V1a), endothelin receptor type A (ETA) and B (ETB).

MATERIALS AND METHODS

Hepatic arteries were collected from 10 donors (noncirrhotic) and 14 recipients (cirrhotic) at liver transplantations. Real-time-PCR was performed to quantify steady-state levels of receptor mRNAs.

RESULTS

alpha 1aAR mRNA levels showed no significant difference between the cirrhotic arteries and the controls while the mRNA levels of the other vasoactive receptors were significantly higher in the cirrhotic hepatic arteries (alpha 1bAR: 4-fold, P = 0.013; AT1: 16-fold, P = 0.024; V1a: 23-fold, P = 0.001; ETA: 4-fold, P = 0.02; ETB: 8-fold, P = 0.008). No mRNA for the alpha 1dAR was detected either in the donor or recipient hepatic arteries.

CONCLUSION

We conclude that vascular hyporeactivity to the most relevant endogenous vasoconstrictors of cirrhotic hepatic arteries is not caused by a receptor down-regulation at mRNA levels. In contrast they were up-regulated.

The effect of hepatic inflow occlusion on laparoscopic radiofrequency ablation using simulated tumors

BACKGROUND

The purpose of this study was to determine the effect of hepatic inflow occlusion (the Pringle maneuver) on laparoscopic radiofrequency (RF) ablation.

METHODS

Using a previously validated agarose tissue-mimic model, 1-cm simulated hepatic tumors (three per animal) were laparoscopically ablated in five pigs with normal perfusion and then in five pigs with hepatic artery and portal vein occlusion. Energy was applied until tissue temperature reached 100 degrees C (warm-up) and thereafter for eight min. Specimens were examined immediately after treatment.

RESULTS

Vascular occlusion was successful in all cases per color-flow Doppler ultrasound. Pringle time was 11.4 +/- 1.6 min. Warm-up time (2.7 +/- 1.4 vs 20.2 +/- 14.0 min) was significantly faster in the Pringle group. Ablation diameter (34.8 +/- 2.9 vs 24.7 +/- 3.1 mm), proportion of round/ovoid lesions (93% vs 20%), ablation symmetry (100% vs 40%), and margin distance (5.1 +/- 3.0 vs 1.1 +/- 1.2 mm) were significantly better for the Pringle group than the No Pringle group, respectively.

CONCLUSION

Using a Pringle maneuver during laparoscopic RF ablation significantly enhances ablation geometry and results in larger margins.

P53 mutation and response to hepatic arterial floxuridine in patients with colorectal liver metastases

PURPOSE

To establish the relationship between the number and site of p53 genomic mutations in metastatic colorectal cancer, and the response to hepatic arterial floxuridine.

METHODS

Liver metastasis biopsies were collected, at the time of laparotomy for hepatic arterial cannulation. in 28 patients with metachronous colorectal liver metastases. p53 Gene mutations were assessed using reverse transcription, nested polymerase chain reaction, single strand conformational polymorphism and gene sequencing. Chemotherapy response was determined from computerised liver tomograms after 4 months of treatment.

RESULTS

Liver metastasis p53 mutation was identified in 21 (75%), and p53 "hot spot" mutation in 11 (39%) patients. There was a significantly lower prevalence (Fisher's, P=0.001) of patients with p53 "hot spot"-mutated liver metastases in stable disease and partial response (5/22) than in progressive (6/6) disease groups. Significantly fewer (Mann-Whitney U, P=0.002) p53 "hot spot" mutations/biopsy were observed in liver metastases from stable disease and partial response (median 0, iqr. 0-0) than in progressive (median 1, iqr 1-2) disease patients. p53 "Hot spot"-mutated liver metastases were associated with significantly shorter survival times (logrank P=0.05) after hepatic arterial floxuridine. Significant response or survival-time differences by total or L2/L3 zinc-binding site p53 mutations were not detected.

CONCLUSIONS

The results support a role for p53 "hot spot" mutations in colorectal liver metastasis resistance to fluorinated pyrimidines, and suggest that the presence of such mutations may be a contra-indication to treatment of colorectal liver metastases with hepatic arterial floxuridine.

Gap junctional communication underpins EDHF-type relaxations evoked by ACh in the rat hepatic artery

Synthetic peptides homologous to the Gap 26 and Gap 27 domains of the first and second extracellular loops of the major vascular connexins (Cx37, Cx40, and Cx43) have been used to investigate the role of gap junctions in endothelium-derived hyperpolarizing factor (EDHF)-type relaxations of the rat hepatic artery. These peptides were designated 37,40Gap 26, 43Gap 26, 37,43Gap 27, and 40Gap 27, according to connexin specificity. When administered at 600 microM, none of the peptides individually affected maximal EDHF-type relaxations to ACh. By contrast, at 300 microM each, paired peptide combinations targeting more than one connexin subtype attenuated relaxation by up to 50%, and responses were abolished by the triple peptide combination 43Gap 26 + 40Gap 27 + 37,43Gap 27. In parallel experiments with A7r5 cells expressing Cx40 and Cx43, neither 43Gap 26 nor 40Gap 27 affected intercellular diffusion of Lucifer yellow individually but, in combination, significantly attenuated dye transfer. The findings confirm that functional cell-cell coupling may depend on more than one connexin subtype and demonstrate that direct intercellular communication via gap junctions constructed from Cx37, Cx40, and Cx43 underpins EDHF-type responses in the rat hepatic artery.

Heterogeneity in mechanisms underlying vasodilatory responses in small arteries of the rat hepatic mesentery

We have characterised nerve-mediated vasodilations in small arteries of the rat hepatic mesentery. Stimulation of sympathetic nerves (10 Hz, 10 s) produced a vasodilation which was abolished by the beta-adrenoceptor antagonist, propranolol (2 x 10(-6) M), but was unaffected by NG-nitro-L-arginine methyl ester (L-NAME, 10(-5) M). Stimulation of sensory nerves produced a large vasodilation that was abolished by capsaicin (10(-6) M). This vasodilation was unaffected by L-NAME (10(-5) M), but significantly reduced by the calcitonin gene related peptide (CGRP) antagonist, CGRP8-37 (10(-6) M), or inhibition of adenylate cyclase (SQ22356, 2 x 10(-5) M; 2',5'-dideoxyadenosine, 2 x 10(-4) M). Stimulation of cholinergic nerves produced a small vasodilation which was significantly reduced by scopolamine (10(-6) M). Expression of mRNA for CGRP1 receptors, muscarinic m2, m3 and m5 receptors and neurokinin1 (NK1) and NK3, receptors was detected. Perivascular nerves were immunoreactive for CGRP and substance P. No role was found for substance P, neuronal NO, ATP or adenosine in nerve-mediated responses. L-NAME (10(-5) M) potentiated vasoconstrictions following sympathetic nerve stimulation. This effect was reversed by L-arginine (10(-3) M) and cromakalim (10(-6) M) and mimicked by glybenclamide (10(-5) M), thus implicating KATP channels. Vasodilation in response to sensory nerve stimulation was directly proportional to the level of preconstriction, while vasodilation in response to neurogenic or applied acetylcholine was inhibited at high levels of preconstriction. We hypothesize that, under conditions of intensive vasoconstriction, some endothelial-dependent vasodilations may be less important than vasodilations activated directly through the smooth muscle.

Levels of interleukin (IL)-6, IL-8, and IL-1 receptor antagonist in the hepatic vein following liver surgery

BACKGROUND/AIMS

The liver produces various cytokines, but local changes in the concentrations of these reaction products after liver surgery are unknown. We investigated the local changes of interleukin-6, interleukin-8 and interleukin-1 receptor antagonist after liver surgery.

METHODOLOGY

We determined levels of interleukin-6, interleukin-8, and interleukin-1 receptor antagonist in the hepatic vein and radial artery after liver resection in 13 patients. These cytokine levels in the portal vein were also measured in 6 patients.

RESULTS

Interleukin-6, interleukin-8, and interleukin-1 receptor antagonist levels were significantly increased during liver surgery (P < 0.05). The level of interleukin-6 was significantly lower in the hepatic vein than in the radial artery as well as in the portal vein at the end of the operation (P < 0.05, < 0.03). The level of interleukin-8 and interleukin-1 receptor antagonist was significantly higher in the hepatic vein than in the artery (P < 0.05).

CONCLUSIONS

Interleukin-6 may be taken up by the liver after liver surgery, and the difference between hepatic venous and peripheral arterial interleukin-6 levels may be an indicator of liver regeneration after liver resection. Interleukin-8 and interleukin-1 receptor antagonist appear to be produced in the remaining liver.

Blockade of nitric oxide synthase potentiates the suppression of vasodilators by norepinephrine in the hepatic artery

We have previously shown that nitric oxide (NO) and adenosine suppress vasoconstriction induced by norepinephrine infusion and sympathetic nerve stimulation in the hepatic artery and superior mesenteric artery. NO is involved in the control of basal vascular tone in the superior mesenteric artery but not the hepatic artery. The vasodilation induced by adenosine is inhibited by NO in the superior mesenteric artery but not in the hepatic artery. Based on these known interactions of catecholamines, adenosine, and NO, the objective of this study was to test the hypothesis that NO modulates the interaction between vasoconstrictors and vasodilators in the hepatic artery. We examined the ability of norepinephrine to suppress adenosine-mediated vasodilation and the role of NO in this interaction. Hepatic arterial blood flow and pressure were monitored in pentobarbital-anesthetized cats. The maximum hepatic arterial vasoconstrictor response to norepinephrine infusion was potentiated by blockade of NO production using Nomega-nitro-L-arginine methyl ester (L-NAME), and the potentiation was reversed by L-arginine. The maximum dilator response to adenosine was only slightly suppressed (14.0+/-5.8%, P < 0.05) by norepinephrine infusion; however, after the NO blockade, the suppression by norepinephrine of the vasodilation induced by adenosine was substantially potentiated (45.2+/-9.1%, P < 0.05). Similar results were obtained for isoproterenol-induced vasodilation. We conclude that the interaction between these vasodilators and norepinephrine was modulated by NO which inhibited the vasoconstriction and the suppression of vasodilators caused by norepinephrine and that in the absence of NO production, norepinephrine-induced constriction and the ability to antagonize dilation is substantially potentiated.

Regional heterogeneities in the production of uric acid from adenosine in the bivascularly perfused rat liver

The heterogeneity of the liver parenchyma in relation to uric acid production from adenosine was investigated using the bivascularly perfused rat liver in the anterograde and retrograde modes. Adenosine was infused in livers from fed rats during 20 min at four different concentrations (20, 50, 100 and 200 microM) according to four experimental protocols as follows: (A) anterograde perfusion, with adenosine infusion into the portal vein; (B) anterograde perfusion, with adenosine in the hepatic artery, (C) retrograde perfusion, with adenosine in the hepatic vein; (D) retrograde perfusion, with adenosine in the hepatic artery. With protocols A, B, and D uric acid production from adenosine was always characterized by initial bursts followed by progressive decreases toward smaller steady-states. With protocol C the initial burst was present only when 200 microM adenosine was infused. The initial bursts in uric acid production were accompanied by simultaneous increases in the ratio of uric acid production/adenosine uptake rate. These initial bursts are thus representing increments in the production of uric acid that are not corresponded by similar increments in the metabolic uptake rates of adenosine. Global analysis of uric acid production revealed that the final steady-state rates were approximately equal for all infusion rates with protocols A, B and C, but smaller with protocol D. This difference, however, can be explained in terms of the differences in accessible cellular spaces, which are much smaller when protocol D is employed. When the analysis was performed in terms of the extra amounts of uric acid produced during the infusion of adenosine, where the initial bursts are also taken into account, different dose-response curves were found for each experimental protocol. These differences cannot be explained in terms of the accessible cell spaces and they are likely to reflect regional heterogeneities. From the various dose-response curves and from the known characteristics of the microcirculation of the rat liver it can be concluded that the initial bursts in uric acid production are generated in periportal hepatocytes. The reason for this heterogeneity could be related to the metabolic effects of adenosine, especially to oxygen uptake inhibition, which is likely to produce changes in the ATP/AMP ratios.

A simple and accurate mathematical method for calculation of the EC50

A simple, accurate, and speedy noncomputational technique for the calculation of the EC50 or any other concentration-related parameter of concentration-effect curves is presented. It avoids the necessity for graph construction or computational curve-fitting programs and allows accurate calculation of the EC50, where the value falls between two known concentrations The technique has been applied to a concentration-response curve constructed to hepatic arterial (HA) vasoconstrictor responses to HA injections of noradrenaline in an isolated dual-perfused rat liver preparation. EC50 values calculated by the new technique were compared to those calculated by conventional, established, noncomputational techniques. The new technique is faster, more accurate, and simpler to perform than other established noncomputational techniques used for the calculation of the EC50 and can be widely applied to many other pharmacological investigations.

Tissue levels of chemotherapeutic agents for hepatic metastasis during hepatic arterial and portal injection

Hepatic metastasis is one of the most important prognostic factors in digestive organ cancer, and hepatic arterial infusion is aggressively performed for therapy of nonresectable metastatic liver cancer. Although comparatively high response rates have been attained in some cases, this treatment has been ineffective in not a few cases because these metastatic tumors are frequently hypovascular in nature. To develop better methods of administering chemotherapeutic agents, we performed basic experiments concerning intraportal administration which has been regarded as having a generally negative effect, focusing on a report indicating that portal supply is dominant along the borders of metastatic liver cancer tumors. VX2 carcinoma cells were inoculated into the hepatic parenchyma beneath the capsule of juvenile Japanese white rabbits. Drugs were infused 2 weeks after the inoculation, then tissue and blood were sequentially sampled. Mitomycin C (1.7 mg/kg) was infused either by bolus injection to the hepatic artery (arterial infusion group) or by bolus injection to the portal vein (portal infusion group). Five-fluorouracil (9.5 mg/kg) and Cisplatin (1.6 mg/kg) were likewise infused continuously over 60 min, and tissue levels of the drugs were compared between the two groups. Mitomycin C and 5-fluorouracil levels were measured by HPLC and Cisplatin levels were measured by atomic absorption spectrophotometry. As a result, the levels of every drug in VX2 tumor tissue did not significantly differ between the arterial infusion group and the portal infusion group, while the levels were significantly higher than those in the intravenous infusion group. Using portal infusion, we observed a drug transition which was not inferior to that of arterial infusion, suggesting that an imported antitumoral effect may be obtained with this method compared with intravenous infusion.

Both positive and negative portal venous and hepatic arterial glucose gradients stimulate hepatic glucose uptake after the same amount of glucose is infused into the splanchnic bed in conscious dogs

We studied the effects of both positive and negative portal venous and hepatic arterial glucose gradients on hepatic glucose uptake after the same amount of glucose was administered into the portal vein and/or hepatic artery. Studies were performed on eight unrestrained conscious dogs with catheters in the portal vein, hepatic vein, gastroduodenal artery, superior mesenteric vein, and femoral artery and Doppler flow probes on the portal vein and hepatic artery. Glucose was infused as follows: protocol 1, 55.6 micromol/kg/min into the portal vein for the first 90 minutes; protocol 2, 27.8 micromol/kg/min into both the portal vein and hepatic artery for the next 90 minutes; and protocol 3, 55.6 micromol/kg/min into the hepatic artery for the last 90 minutes. The portal venous and hepatic arterial plasma glucose gradient was 2.1+/-0.3, -3.0+/-0.5, and -7.1+/-0.6 mmol/L, the rate of hepatic glucose uptake divided by the administered glucose load was 46%+/-11%, 42%+/-10%, and 57%+/-8%, net hepatic glucose uptake was 25.4+/-5.9, 23.5+/-5.6, and 31.6+/-4.6 micromol/kg/min; and the fractional hepatic extraction of glucose was 10.7%+/-2.2%, 11.6%+/-2.5%, and 15.0%+/-2.1%, respectively (mean+/-SEM of three points at 60, 75, and 90 minutes in each protocol). The rate of hepatic glucose uptake divided by the administered glucose load, net hepatic glucose uptake, and fractional hepatic extraction of glucose did not change significantly despite the various portal venous and hepatic arterial glucose gradients. We also studied the effect of the same amount of intraportal glucose infusion for 240 minutes on net hepatic glucose uptake. From 60 to 240 minutes, net hepatic glucose uptake did not change significantly. In conclusion, the liver took up a large amount of glucose administered into the portal vein and/or hepatic artery, regardless of positive or negative portal venous and hepatic arterial glucose gradients. Augmentation of hepatic glucose uptake is not dependent on the signal of the positive or negative portal venous and hepatic arterial glucose gradient.

Differential regulation of hepatic arterial and portal venous vascular resistance by nitric oxide and carbon monoxide in rats

Nitric oxide (NO), a gaseous mediator that accounts for the biological activity of endothelium-derived relaxing factor, has been shown to play an important role in the reduction of basal vascular tone in multiple vascular beds, including the hepatic circulation. On the other hand, recent studies have provided first evidence that endogenously generated carbon monoxide (CO) may exert vasodilatory effects in the hepatic portal vein and within sinusoids. Thus, we defined the differential role of NO and CO in the regulation of vascular resistance in the two inflows to the liver in the normal rat in vivo. Male Sprague-Dawley rats were anesthetized with pentobarbital sodium and surgically instrumented in order to study the change in hepatic arterial (Rha) and portal venous vascular resistance (Rpv) in response to intravenous bolus administration of either the NO-synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) (1 mg/kg; n = 7 animals) or of tin protoporphyrin-IX (SnPP-IX) (50 micromol/kg), a specific inhibitor of the CO-generating enzyme heme oxygenase (n = 8 animals). While L-NAME caused a substantial increase in Rha, Rpv increased only slightly under these conditions. In sharp contrast, SnPP-IX did not affect Rha, but caused a profound increase in Rpv. In conclusion, Rha and Rpv are differentially regulated by NO and CO in the normal rat liver in vivo, i.e., NO serves as a potent vasodilator in the hepatic arterial circulation, but exerts only a minor vasodilatory effect in the portal venous vascular bed. In contrast, while there is no intrinsic CO-mediated vasodilation in the hepatic artery, CO acts to maintain portal venous vascular tone in a relaxed state.

[Study of disposition of adriamycin and mitomycin C in liver by determination of plasma concentrations in hepatic vein and artery during intravenous constant infusion in rats]

The hepatic extraction ratios (EH) of adriamycin (ADR) and mitomycin C (MMC), which were administered clinically by an intra-hepatic arterial route, were measured in rats to clarify the disposition of ADR and MMC in liver. EH values of ADR and MMC were determined by comparing the femoral arterial and hepatic venous plasma concentrations at steady state during continuous intravenous administration. The EH value of ADR in rats at each infusion rate of 2, 10 and 50 micrograms/kg/min, was 0.290, 0.286 and 0.251, respectively. There was no significant difference between the EH values (p > 0.05). The systemic clearance (CLtot) at each infusion rate was 108, 77.6 and 72.9 ml/min/kg, respectively. The EH value of MMC in rats at each infusion rate of 2.5, 7.5 and 25 micrograms/kg/min, was 0.332, 0.358 and 0.360, respectively. There was no significant difference between the EH values, the same as for ADR. The systemic clearance (CLtot) at each infusion rate was 38.3, 36.1 and 35.3 ml/min/kg.

Involvement of voltage-dependent potassium channels in the EDHF-mediated relaxation of rat hepatic artery

1. In the rat hepatic artery, the acetylcholine-induced relaxation mediated by endothelium-derived hyperpolarizing factor (EDHF) is abolished by a combination of apamin and charybdotoxin, inhibitors of small (SKCa) and large (BKCa) conductance calcium-sensitive potassium (K)-channels, respectively, but not by each toxin alone. The selective BKCa inhibitor iberiotoxin cannot replace charybdotoxin in this combination. Since delayed rectifier K-channels (KV) represent another target for charybdotoxin, we explored the possible involvement of KV in EDHF-mediated relaxation in this artery. 2. The KV inhibitors, agitoxin-2 (0.3 microM), kaliotoxin (0.3 microM), beta-dendrotoxin (0.3 microM), dofetilide (1 microM) and terikalant (10 microM), each in combination with apamin (0.3 microM) had no effect on the EDHF-mediated relaxation induced by acetylcholine in the presence of N omega-nitro-L-arginine (0.3 mM) and indomethacin (10 microM), inhibitors of nitric oxide (NO) synthase and cyclo-oxygenase, respectively (n = 2-3). Although the KV inhibitor margatoxin (0.3 microM) was also without effect (n = 5), the combination of margatoxin and apamin produced a small inhibition of the response (pEC50 and Emax values were 7.5 +/- 0.0 and 95 +/- 1% in the absence and 7.0 +/- 0.1 and 81 +/- 6% in the presence of margatoxin plus apamin, respectively; n = 6; P < 0.05). 3. Ciclazindol (10 microM) partially inhibited the EDHF-mediated relaxation by shifting the acetylcholine-concentration-response curve 12 fold to the right (n = 6; P < 0.05) and abolished the response when combined with apamin (0.3 microM; n = 6). This combination did not inhibit acetylcholine-induced relaxations mediated by endothelium-derived NO (n = 5). 4. A 4-aminopyridine-sensitive delayed rectifier current (IK(V)) was identified in freshly-isolated single smooth muscle cells from rat hepatic artery. None of the cells displayed a rapidly-activating and -inactivating A-type current. Neither charybdotoxin (0.3 microM; n = 3) nor ciclazindol (10 microM; n = 5), alone or in combination with apamin (0.3 microM; n = 4-5), had an effect on IK(V). A tenfold higher concentration of ciclazindol (0.1 mM, n = 4) markedly inhibited IK(V), but this effect was not increased in the additional presence of apamin (0.3 microM; n = 2). 5. By use of membranes prepared from rat brain cortex. [125I]-charybdotoxin binding was consistent with an interaction at a single site with a KD of approximately 25 pM. [125I]-charybdotoxin binding was unaffected by iberiotoxin (0.1 microM, n = 6), but was increased by apamin in a concentration-dependent manner (Emax 43 +/- 10%, P < 0.05 and pEC50 7.1 +/- 0.2; n = 7-8). Agitoxin-2 (10 nM) displaced [125I]-charybdotoxin binding by 91 +/- 3% (n = 6) and prevented the effect of apamin (1 microM; n = 6). 6. It is concluded that the EDHF-mediated relaxation in the rat hepatic artery is not mediated by the opening of either KV or BKCa. Instead, the target K-channels for EDHF seem to be structurally related to both KV and BKCa. The possibility that a subtype of SKCa may be the target for EDHF is discussed.

[Distribution and significance of endothelin-1 and endothelin receptor a mRNA in liver after endotoxemia]

OBJECTIVE

To study the distribution and significance of endothelin-1 (ET-1) and endothelin receptor A (ETAR) mRNA in liver after endotoxemia using situ hybridization.

METHODS

30 rats were randomized into control and endotoxin groups. The endotoxin group was injected with endotoxin at a dose of 10 mg/kg body wt. Hybridization of ET-1 and ETAR mRNA of the hepatic tissue was proceeded at 3, 6, 12 and 24 hours after endotoxin administration.

RESULTS

By in situ hybridization, the cell expression of ET-1 mRNA was hepatic sinusoids, the endothelial cells of portal vein, and Kupffer cell and the cell expression of ETAR mRNA was the small artery smooth muscle cells of hepatic lobule and the hepatic sinusoidal lining cells. The accumulation of grain was observed in many cells of the liver. The number of accumulating grain increased in unit scope.

CONCLUSION

ET-1 is synthesized by the hepatic sinusoids, hepatic vascular endothelial cells, and Kupffer cells, ETAR may be located on the hepatic vascular smooth muscle cells and Ito cells (fat-storing cells) around sinusoid. Endotoxin may, on transcription and translation level, lead to the increase of ET-1 and ETAR in synthesis and release.

[Adrenoceptors in the hepatic tissues in cirrhotic rats and cirrhotic patients with portal hypertension]

OBJECTIVE

To study the density of alpha 1-adrenoceptors on hepatic tissues of cirrhotic rats and cirrhotic patients with portal hypertension.

METHODS

A light autoradiography of alpha 1-adrenoreceptors on hepatic tissues of Wistar rats in the process of CC1(4)-induced cirrhosis (n = 18) and hepatitis virus B-related cirrhotic patients (n = 8) were studied.

RESULTS

The density of alpha 1-adrenoceptors on hepatic tissues (per 10,000 microns2) in rats (normal/cirrhotic early stage/cirrhotic middle stage/cirrhotic advanced stage) was 946 +/- 100/431 +/- 54/567 +/- 92/692 +/- 55 for hepatocytes, 581 +/- 90/250 +/- 87/273 +/- 92/273 +/- 88 for intrahepatic artery walls, 470 +/- 83/260 +/- 75/258 +/- 77/253 +/- 83 for intrahepatic portal walls, 362 +/- 92/229 +/- 64/218 +/- 87/212 +/- 90 for hepatic venule walls and in patients (control human beings/cirrhotic patients) it was 1255 +/- 151/583 +/- 48 for hepatocytes, 705 +/- 189/184 +/- 47 for intrahepatic artery walls 410 +/- 89/ 154 +/- 21 for intrahepatic portal walls 339 +/- 95/... ...for hepatic venule walls.

CONCLUSION

The density of alpha 1-adrenoceptors on various hepatic structures in cirrhotic rats and cirrhotic patients are significantly lower than that in normal rats and control human beings (P < 0.01).