Direct measurement of hepatic tissue hypoxia by using a novel tcpO2/pCO2 monitoring system in comparison with near‐infrared spectroscopy

Abstract: Background/Aims: Hepatic hypoxia occurs during liver surgery and transplantation and it may also appear within liver tumours, correlating with prognosis and efficacy of the treatment. The present study measured liver tissue hypoxia by directly using near‐infrared spectroscopy (NIRS) and a novel tcpO₂/pCO₂ monitoring system. Methods: Graded hypoxia was achieved in a rabbit model by a stepwise reduction of the fraction of inspired oxygen (FiO₂) from 0.3 to 0.0. Animals were allowed to recover from hypoxia at FiO₂ of 3.0 indicated by normalised arterial blood gas values. Hepatic tissue oxyhaemoglobin (HbO₂), deoxyhaemoglobin (Hb), cytochrome oxidase (Cyt Ox), oxygen partial pressure (pO₂) and carbon dioxide partial pressure (pCO₂) were measured continuously with the help of NIRS and a Clark‐type surface tcpO₂/pCO₂ monitoring system, throughout the period of hypoxaemia. Results: There was an immediate reduction in hepatic HbO₂ with hypoxia and a simultaneous increase in hepatic Hb. Similarly, hepatic tissue pO₂ decreased significantly but tissue pCO₂ remained unchanged until the FiO₂ was below 0.1. Hepatic HbO₂ showed a positive correlation with tissue pO₂ (r = 0.53, P < 0.001). Hepatic Hb showed a negative correlation with tissue pO₂ (r = 0.47, P < 0.001). Hepatic Cyt Ox decreased significantly with an FiO₂ of 0.1 or less and showed a positive correlation with hepatic tissue pO₂ (r = 0.64, P < 0.001). A significant correlation was found between hepatic tissue pO₂ and arterial blood pO₂ (r = 0.44, P < 0.001). Arterial blood pCO₂ also correlated with hepatic tissue pCO₂ (r = 0.53, P < 0.001) measured by the tcpO₂/pCO₂ monitoring system. Conclusion: The data from the present study suggest that, like NIRS, the tcpO₂/pCO₂ monitoring system can be reliably used for the direct monitoring of hepatic tissue oxygenation in vivo.     

Assessment of hepatic ischaemia reperfusion injury by measuring intracellular tissue oxygenation using near infrared spectroscopy

AIMS/BACKGROUND: Hepatic ischaemia/reperfusion (I/R) injury is a major cause of liver damage during liver surgery and transplantation. The relationship between the severity of I/R injury and the degree of intracellular hypoxia has not been investigated. METHODS: New Zealand white rabbits were used in 4 groups (n=6 each). At laparotomy, left lobe hepatic ischaemia was produced for 30, 45, or 60 min followed by 60 min reperfusion and compared with controls. Liver function, bile flow, and flow in the hepatic microcirculation (HM) were measured. Near infrared spectroscopy (NIRS) was used to monitor hepatic oxyhaemoglobin (HbO2), deoxyhaemoglobin (Hb), and cytochrome oxidase (Cyt Ox). RESULTS: I/R injury produced deranged liver function tests, reduced bile flow, and reduced flow in the microcirculation in comparison with controls. During ischaemia, HbO2 and Cyt Ox were significantly reduced in comparison with controls. After reperfusion, a biphasic change in tissue oxygenation was observed, with an initial increase in HbO2 and Cyt Ox followed by a progressive reduction. The reduction in tissue oxygenation with ischaemia and reperfusion paralleled the ischaemia time. After I/R, the changes in Cyt Ox (intracellular oxygenation) significantly correlated with the parameters of hepatocellular injury to a higher degree than HbO2 (extracellular oxygenation). CONCLUSION: This study shows the potential of monitoring the degree of I/R injury by measuring hepatic tissue intracellular oxygenation.     

Oxygen metabolism of the liver during an HA clamp: HV saturation and free radicals

BACKGROUND/AIMS: To clarify changes in the hepatic oxygen metabolism and tissue damage resulting from oxygen-derived free radical generation from polymorphonuclear cells during a hepatic arterial clamp. METHODOLOGY: Subjects were 32 male Wistar rats. Hepatic tissue blood flow, and hepatic venous chemiluminescence, indicating oxygen-derived free radicals from polymorphonuclear cells, and liver lipid peroxide were measured, and hepatic and portal venous blood gas analysis were performed before and after 130 minutes of hepatic arterial clamping. RESULTS: Hepatic tissue blood flow decreased by hepatic arterial clamp. The values of hepatic arterial oxygen pressure (HTBF), hepatic venous oxygen saturation (ShvO2), and O2 contents after hepatic arterial clamp were lower than those before hepatic arterial clamp (P = 0.035, 0.024, and 0.028, respectively). Hepatic venous chemiluminescence decreased and the lipid peroxide level of the liver increased by hepatic arterial clamp (P = 0.001). CONCLUSIONS: ShvO2 is useful for the evaluation of hepatic oxygen metabolism and hepatic tissue blood flow during acute hepatic arterial clamp. This condition should prepare the following tissue damage due to oxygen-derived free radicals from polymorphonuclear cells.     

The role of nitric oxide in the modulation of hepatic microcirculation and tissue oxygenation in an experimental model of hepatic steatosis

BACKGROUND: Impairment of hepatic microcirculation in fatty liver has been assumed to reduce tolerance of the liver against ischemia-reperfusion injury. The present study was aimed to investigate the role of nitric oxide (NO) in the regulation of hepatic microcirculation and tissue oxygenation in hepatic steatosis. METHODS: Sprague-Dawley rats (200-250 g) were fed a 2% cholesterol diet (n = 12) to induce hepatic steatosis or normal diet (n = 12) served as controls for 12 weeks. Hepatic blood flow, microcirculation, tissue oxyhemoglobin (HbO2) and cytochrome c oxidase radox status (Cyt Ox) in response to intravenous bolus administrations of l-arginine (300 mg/kg) or l-NAME (20 mg/kg) were assessed. RESULTS: Animals which developed moderate hepatic steatosis showed significant increase in tissue level of total lipids. Portal blood flow and hepatic microcirculation were significantly reduced as compared to controls (5.7 +/- 0.9 vs. 9.7 +/- 0.9 ml/min, P = 0.003 and 114.5 +/- 9.5 vs. 167.3 +/- 10.0 flux unit, P = 0.003). l-Arginine improved hepatic arterial and portal blood flows as well as microcirculation in fatty livers (P < 0.05), while l-NAME significantly worsened these parameters (P < 0.05). Hepatic tissue HbO2 and Cyt Ox were improved both in fatty and control livers following l-arginine, while l-NAME resulted in decreased HbO2 and Cyt Ox although a transit increase in tissue oxygenation was observed in fatty livers. CONCLUSIONS: NO is involved in the modulation of hepatic microcirculatory perfusion and oxygenation in cholesterol-induced hepatic steatosis. NO metabolisms may be regulated as a potential therapeutic strategy for impaired microcirculation in hepatic steatosis.     

Hepatic arterial pulsatility index in cirrhosis: correlation with portal pressure.

BACKGROUND/AIMS: Determination of the pulsatility index by means of duplex sonography provides the opportunity to evaluate the vascular resistance of the hepatic artery noninvasively. The aim of this study was to investigate the relationship between the hepatic arterial pulsatility index and the hepatic venous pressure gradient in cirrhosis. METHODS: In 50 patients with cirrhosis, hepatic venous pressure gradient was determined in the fasting state. Immediately thereafter, hepatic arterial pulsatility index and portal blood flow velocity were measured by duplex sonography with no knowledge of hepatic venous pressure values. In addition, the duplex parameters were determined in 20 controls. RESULTS: Hepatic arterial pulsatility index was significantly higher in patients with cirrhosis than in controls (0.92+/-0.1 vs. 1.14+/-0.18; p<0.001) and directly correlated with the hepatic venous pressure gradient (r = 0.7; p<0.001). Furthermore, weak correlations were found between hepatic arterial pulsatility index and Child-Pugh score (r = 0.49; p<0.01) and between portal blood flow velocity and hepatic venous pressure gradient (r = -0.48; p<0.01). CONCLUSION: In cirrhosis the hepatic arterial vascular resistance seems to increase parallel to the rise of the portal pressure. Therefore, duplex sonographic determination of the hepatic arterial pulsatility index may contribute to the noninvasive evaluation of portal hypertension.     

Cerebral oxygen monitoring during neonatal cardiopulmonary bypass and deep hypothermic circulatory arrest

BACKGROUND: This study was undertaken to investigate the physiological effects of cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) on cerebral oxygen metabolism estimated by near-infrared spectroscopy (NIRS). METHODS: Ten newborn piglets (2.1 to 2.6 kg) were monitored with right frontal NIRS; the right jugular bulb was cannulated for intermittent sampling of jugular venous blood. All animals underwent CPB, cooling to a core temperature below 15 degrees C, 60 minutes of DHCA followed by subsequent reperfusion and rewarming. Continuously recorded NIRS data and intermittent jugular venous blood values were compared. RESULTS: NIRS performance was examined over the jugular venous oxygen saturation (SjvO2) range of 40 to 98 %, a linear correlation was found between SjvO2 and NIRS-derived regional cerebral oxygen saturation (rSO2) (r = 0.91, p < 0.001). A correlation was observed between the cellular oxidation NIRS-parameter cytochrome oxidase aa3 (CytOx) slope during the DHCA period in relation to rectal and nasopharyngeal temperature immediately before the onset of DHCA (r = 0.75 and 0.85, p < 0.001). CONCLUSIONS: This study suggests that NIRS-measured hemoglobin oxygenation parameters may reflect functional changes in cerebral hemodynamics and brain tissue oxygenation, while CytOx values represent related effects on intracellular oxidative metabolism.     

Lactic acidosis in fulminant hepatic failure. Some aspects of pathogenesis and prognosis

To obtain further evidence of tissue hypoxia in fulminant hepatic failure, we have measured the mixed venous lactate concentration and the acid-base status of 32 patients at the time of their admission, in grade III or IV encephalopathy. The mixed venous lactate was elevated in 26 of the 32 patients (median 5.0 mmol/l, range 0.8-21.1 mmol/l), and, in 17 patients, this was associated with evidence of a metabolic acidosis. Mixed venous lactate levels correlated inversely with the mean arterial pressure (r = 0.56, P less than 0.005), systemic vascular resistance (r = 0.62, P less than 0.001) and the oxygen extraction ratio (r = 0.44, P less than 0.02). The 17 patients with a raised mixed venous lactate and metabolic acidosis had a significantly reduced systemic vascular resistance and oxygen extraction ratio compared with the other 15 (median systemic vascular resistances 944 and 1710 dyne X s/cm5/m2, respectively, P less than 0.05, median oxygen extraction ratios 19 and 23%, respectively, P less than 0.05). Survival was markedly reduced in the patients with hyperlactataemia and a metabolic acidosis, and only one out of the 17 survived compared with 12 of the remaining 15, P = 0.0002. These results suggest that lactic acid accumulation may be in part the consequence of tissue hypoxia that develops as a result of arteriovenous shunting, reflected in the reduction in systemic vascular resistance. This tissue hypoxia may occur despite apparently adequate systemic blood pressure, flow and oxygenation.     

Effects of vasopressor agents and epoprostenol on systemic hemodynamics and oxygen transport in fulminant hepatic failure.

Hypotension is a serious complication in patients with fulminant hepatic failure, because it is associated with tissue hypoxia and a further compromise to end-organ function. In this study we investigated the effects of epinephrine and norepinephrine on hemodynamics and oxygen transport variables in 30 patients with fulminant hepatic failure. All had a mean arterial pressure of less than 60 mm Hg, despite adequate intravascular filling pressures. Both epinephrine (n = 15) and norepinephrine (n = 15) improved mean arterial pressure (p less than 0.001 epinephrine and norepinephrine), although this was not associated with a rise in oxygen delivery. Oxygen consumption fell (p less than 0.05 epinephrine, p less than 0.001 norepinephrine) because of a lower oxygen extraction ratio (p less than 0.01 epinephrine and norepinephrine). The addition of epoprostenol, a microcirculatory vasodilator, in 10 patients from each group led to an increase in oxygen consumption (p less than 0.001 epinephrine and norepinephrine) because of a rise in oxygen delivery (p less than 0.05 epinephrine, p less than 0.01 norepinephrine) and oxygen extraction ratio (p less than 0.01 epinephrine, p less than 0.001 norepinephrine), without a fall in mean arterial pressure. The fall in oxygen consumption after the institution of vasopressor therapy could exacerbate tissue hypoxia and thus contribute to further organ damage in an already susceptible patient. In patients with fulminant hepatic failure who are given vasopressor support, the addition of epoprostenol may prevent the development of tissue hypoxia.     

The effect of consecutively larger doses of l-arginine on hepatic microcirculation and tissue oxygenation in hepatic steatosis

Background: Impairment of hepatic microcirculation in fatty liver is thought to render it more susceptible to the effects of ischaemia–reperfusion injury as compared to non-fatty liver grafts. The present study aimed to investigate the effect of consecutively larger doses of l-arginine on the hepatic microcirculation and tissue oxygenation of fatty liver.Methods: Sprague–Dawley rats (200–250 g) were fed a liquid ethanol diet to induce hepatic steatosis or a normal diet for 6 weeks. Hepatic blood flow, microcirculation, tissue oxyhaemoglobin (HBO₂) in response to consecutive intravenous bolus administrations of l-arginine (50 mg/kg, 100 mg/kg, 300 mg/kg and 500 mg/kg) or normal saline, were assessed.Results: Baseline hepatic arterial flows and hepatic microcirculation values were significantly lower in steatotic livers vs. control livers. l-arginine significantly improved hepatic arterial, portal venous blood flow, hepatic microcirculation and tissue oxygenation in both fatty and control livers.Conclusions: The administration of NO in cumulatively larger doses is effective at improving hepatic blood flow, microcirculation and hepatic tissue oxygenation in steatotic liver and these results could form the basis of further work into using NO as a therapeutic tool to reclaim moderately steatotic grafts for use in liver transplantation.     

A role for near infrared spectroscopy in the assessment of intermittent claudication.

BACKGROUND: Near infrared spectroscopy (NIRS) can be used to monitor muscle oxyhemoglobin (HbO2), deoxyhemoglobin (Hb) and cytochrome oxidase (CytOx) oxidation. We evaluated the changes in NIRS in patients with intermittent claudication (IC) pre- and postexercise. Microalbuminuria is an index of endothelial dysfunction. Therefore, we also assessed whether the urinary excretion of albumin increased postexercise in patients with IC. METHODS: Each participant (14 patients with IC and 10 controls) underwent a treadmill test; NIRS was continuously recorded. The urinary albumin:creatinine ratio (ACR) and ankle: brachial systolic pressure index (ABPI) were measured pre- and postexercise. RESULTS: The ABPI in the claudicants dropped significantly (p<0.001) postexercise. The pre-exercise ACR did not differ between claudicants and controls but postexercise, the ACR increased significantly (p<0.001) in the claudicants. There was a significant (p<0.001) difference in the degree of HbO2 deoxygenation between claudicants and controls; the rate of deoxygenation was significantly higher in claudicants than in controls (-8.4 vs. -3.4 mol/L.min, p=0.024). The period of recovery of HbO2 postexercise was also significantly slower in claudicants (192 vs 68 sec, p=0.003). There was a significant correlation between the increase in the ACR and time of recovery of HbO2 levels postexercise (r=0.86, p<0.001, n=24). A similar pattern was seen with CytOx. CONCLUSIONS: NIRS may provide a simple, non-invasive assessment of the severity of IC. Furthermore, because the ACR is a marker of endothelial damage, it is possible that NIRS changes also reflect endothelial integrity. These applications of NIRS technique should be assessed in a larger study.     

Increased NAD(P)H fluorescence with decreased blood flow in the steatotic liver of the obese Zucker rat

The steatotic liver is characterized by deranged intrahepatic microvasculature that is believed to predispose it to ischemia-reperfusion injury. The aim of this study was to investigate the distorted hepatic hemodynamics and its impact on the redox status of the steatotic liver. Hepatic hemodynamic parameters, hepatic microcirculatory perfusion (HMP), and in vivo reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] autofluorescence, which reflects the mitochondrial redox status and tissue oxygen levels, were measured in obese (n = 7) and lean Zucker rats (n = 7). Portal venous and total hepatic blood flow per unit of liver weight were found to exhibit a 37.9% and 35.9% reduction, respectively, in the steatotic liver compared to the nonsteatotic liver of the lean group (P < 0.0001) as was HMP (obese, 96.1 +/- 18.1 PU; lean, 143.8 +/- 12.0 PU, P < 0.05) that showed a 33.2% decrease in the former. Hepatic arterial resistance, however, was 38.7% lower in the obese rat (83.1 +/- 9.1 mmHg. ml(-1). min) than in the lean rat (135.5 +/- 15.8 mmHg. ml(-1). min) (P < 0.05). NAD(P)H fluorescence intensity was significantly elevated in the steatotic liver (0.16 +/- 0.001 aU) compared with the lean one (0.14 +/- 0.007 aU) (P = 0.014). Our results suggest that, in response to a reduced portal venous blood flow, there is a significant decrease in hepatic arterial resistance that, nevertheless, cannot completely compensate for the drop in overall hepatic perfusion and oxygenation of the microvascular bed in the steatotic liver of the obese Zucker rat.     

The effect of mechanically enhancing portal venous inflow on hepatic oxygenation, microcirculation, and function in a rabbit model with extensive hepatic fibrosis.

Enhancing the portal venous blood flow (PVBF) has been shown to reduce portal pressure and intrahepatic vascular resistance and to improve liver function in isolated cirrhotic rodent livers in vitro. The aim of this study was to assess the short-term effect of mechanically pumping the portal inflow on hepatic microcirculation (HM), oxygenation, and function in an animal model of extensive hepatic fibrosis. New Zealand white rabbits underwent laparotomy and exposure of the liver: group 1 (n = 7) were normal controls; group 2 (n = 7) had hepatic fibrosis. Total hepatic blood flow (THBF) and HM was measured along with continuous monitoring of intrahepatic tissue oxygenation using near infrared spectroscopy (NIRS). Baseline hepatic hemodynamics and liver function were measured in both groups. PVBF was then increased by 50% over a 3-hour period in the hepatic fibrosis group using a miniature portal pump designed for human implantation, and the hemodynamics were monitored continuously. Liver function tests were repeated after portal pumping. In comparison with normal controls, animals with hepatic fibrosis had a higher portal pressure (13.0 +/- 3.6 vs. 3.7 +/- 1.4 mm Hg, P <.001, mean +/- SD vs. controls), reduced PVBF (52.4 +/- 24.6 vs. 96.9 +/- 21.1 mL/min, P =.003), and increased portal vascular resistance (P =. 001). THBF and flow in the HM was lower than in controls, and liver function tests were abnormal. After a 3-hour period of enhanced portal flow in animals with hepatic fibrosis, the portal pressure greatly reduced (13.0 +/- 3.6 to 2.5 +/- 1.1 mm Hg, P <.001) as did the intrahepatic portal resistance (0.32 +/- 0.18 to 0.04 +/- 0.03 mm Hg/mL/min, P =.006). Flow in the HM improved (143 +/- 16 to 173 +/- 14 flux units, P =.006) and was associated with improved hepatic tissue oxygenation, tissue oxy-hemoglobin (HbO2) and cytochrome oxidase being increased by 24.4 +/- 7.5 and 5.65 +/- 2.30 micromol/L above the baseline value (P <.001), respectively. A 3-hour period of mechanical portal pumping produced a dramatic improvement in liver function, bilirubin (41.1 +/- 25.9 to 10.0 +/- 5.9 micromol/L, P =. 040), aspartate transaminase (AST) (135.5 +/- 52.3 to 56.3 +/- 19.8 U/L, P =.006) and lactate dehydrogenase (LDH) (2,030.1 +/- 796.3 to 1,309.8 +/- 431.6 IU/L, P =.006; prepumping vs. postpumping, all P <. 050). In conclusion, portal pumping in this rabbit model with extensive hepatic fibrosis improved liver parenchymal perfusion, oxygenation, and function.     

Relationship among histologic, radiologic, and biochemical assessments of hepatic steatosis: a study of human liver samples

BACKGROUND AND AIMS: In patients with nonalcoholic fatty liver disease, there is not a consistent relationship between severity of steatosis and the presence of steatohepatitis. This leads to the possibility that severity of steatosis is not an important factor in the pathogenesis of nonalcoholic steatohepatitis. Alternatively, it is possible that currently used method to quantify hepatic steatosis (histologic grading) may not accurately reflect hepatic lipid content. Therefore, we examined the relationship between hepatic triglyceride (TG) content and nonbiochemical assessment of steatosis in 38 human liver samples. METHODS: Hepatic steatosis was histologically graded by the 3 hepatopathologists and hepatic TG levels were determined from liver homogenate. Additionally, we characterized the relationship between (a) hepatic steatosis quantified by magnetic resonance spectroscopy (MRS) and histologic grading and hepatic TG content and (b) hepatic long-chain polyunsaturated fatty acid n-6/n-3 ratio and the severity of steatosis. RESULTS: Twenty-two samples had <5% steatosis, 9 had 5% to 33% steatosis and 7 had >33% steatosis. The mean (+/-SD) hepatic TG was 1.8+/-1.3 mg/mg of protein and MRS fat score was 6.4+/-6.0. There was a significant correlation between histologic grading and hepatic TG content (r=0.64, P<0.001). A significant correlation existed between MRS fat score and histologic grading (r=0.61, P=0.006), and hepatic TG (r=0.63, P=0.004). Severity of steatosis as graded histologically had significant correlation with n-6/n-3 ratio (r=0.61, P<0.001). CONCLUSIONS: Hepatic steatosis quantified by histologic grading or by MRS is significantly reflective of hepatic TG content. Further research is needed to investigate the relationship we observed between n-6/n-3 ratio and the severity of steatosis.     

Portal hypertension in acute liver failure.

Twenty five patients with acute liver failure were measured for hepatic venous pressure gradient as an index of portal pressure during the course of a transjugular liver biopsy. Hepatic venous pressure gradient ranged from 4 to 24.5 mm Hg with a mean of 12.8 (5.3) mm Hg (normal values less than 5 mm Hg). All patients but one had increased portal pressure gradient. Portal hypertension correlated with the degree of architectural distortion of the liver, as suggested by a direct correlation between hepatic venous pressure gradient and the area of reticulin collapse, evaluated by means of a morphometric analysis on Sirius red stained liver slides (r = 0.43, p less than 0.05). Hepatic venous pressure gradient was significantly higher in patients with ascites (15.1 (5) mm Hg, n = 15) or renal failure (14.4 (5.3) mm Hg, n = 16) than in those without (9.3 (3.4) mm Hg and 10.1 (4) mm Hg, respectively; p less than 0.05). Portal hypertension was associated with systemic vasodilation and a hyperkinetic circulatory state, with decreased arterial pressure, and peripheral resistance and increased cardiac output.     

Correlation between arterial blood pressure and oxygenation in tetralogy of fallot

To examine the relationship between arterial blood pressure and oxygenation in patients undergoing complete surgical correction of tetralogy of Fallot, a retrospective study of 16 patients was first performed, looking at the correlation between mean arterial blood pressure (MAP) and arterial oxygen tension (PaO₂ The correlation between phenylephrine-induced changes in MAP (Δ MAP) and those in PaO₂ (Δ PaO₂ was investigated prospectively in seven patients. In the retrospective study, there was a significant correlation between MAP and (PaO₂ (n = 66; r = 0.55; P < 0.01), and most data points with a PaO₂ <50 mm Hg were associated with a MAP <60 mm Hg. In the seven patients who received phenylephrine, 10 μg/kg, a significant correlation was found between Δ MAP and Δ (PaO₂ (n = 10; r = 0.95; P < 0.01). These results suggest that in tetralogy of Fallot arterial blood pressure is a determinant of arterial oxygenation, and that the risk of serious hypoxia is significant when MAP is <60 mm Hg.     

Influence of hepatic arterial blockage on blood perfusion and VEGF,MMP—1 expression implanted liver cancer in rats

AIM：To investigate the influence of hepatic arterial blodckage on blood perfusion of transplanted cancer in rat liver and the expression of vascular endothelial growth factor (VEGF)and matrix metalloproteinase-1(MMP-1),and to explore the mechanisms involved in transarterial embolization(TAE)-induced metastasis of liver cancer preliminarily.METHODS:Walker 256 carcinosarcoma was transplanted in to rat liver to establish the liver cancer model.Hepatic arterial ligation(HAL) was used to block the hepatic arterial blood supply and simulate TAE.Blood perfusion of tumor in control laparotomy control,and HAL group was analyzed by Hoechst 33342 labeling assay,the serum VEGF level was assayed by ELISA,the expression of VEGF and MMP-1 mRNA was detected by in situ hybridization.RESULTS:Two days after HAL.the number of Hoechst 33 342 labeled cells which represent the blood perfusion of tumor directly and hypoxia of tumor indirectliy in HAL group decreased significantly compared with that in control group (329&#177;29VS 384&#177;19,P&lt;0.01),The serum VEGF level in the HAL group increased significantly as against that of the control group (93ng.L^-1&#177;44ng.L^-1VS55ng.L^-1&#177;19ng.L^-1,P&lt;0.05),The expression of VEGFand MMP-1 mRNA in the tumor tissue of the HAL group increased significantly compared with that of the control and the laparotomy control groups(P&lt;0.05),The blood perfusion data of the tumor represented by the number of Hoechst 33342 labeled cells,showed a good linear inverse correlation with the serum VEGF level(r=-0.606,P&lt;0.05),and the expression of VEGF mRNA in the tumor tissue(r=-0.338,P&lt;0.01).CONCLUSION:Blockage of hepatic arterial blood supply results in decreased blood perfusion and increased expression of metastasis-associated genes VEGF and MMP-1 of transplanted liver cancer in rats .Decreased blood Perfusion and hypoxia may be the major cause of upregulated expression of VEGF.&#177;&#177;     

Influence of hepatic arterial blockage on blood perfusion and VEGF, MMP-1 expression of implanted Iiver cancer rats

AIM: To investigate the influence of hepatic arterial blockageon blood perfusion of transplanted cancer in rat liver and theexpression of vascular endothelial growth factor (VEGF)and matrix metalloproteinase-1 (MMP-1), and to explore themechanisms involved in transarterial embolization (TAE)-induced metastasis of liver cancer preliminarily.METHODS: Wallker 256 carcinosarcoma was transplanted intorat liver to establish the liver cancer model. Hepatic arterialligation (HAL) was used to block the hepatic arterial bloodsupply and simulate TAE. Blood perfusion of tumor incontrol, laparotomy control, and HAL group was anslyzedby Hoechst 33 342 labeling assay, the serum VEGF level wasassayed by ELISA, the expression of VEGF and MMP-1mRNA was detected by in situ hybridization.RESULTS: Two days after HAL, the number of Hoechst 33342 labeled cells which represent the blood perfusion oftumor directly and hypoxia of tumor indirectly in HAL groupdecreased significantly compared with that in control group(329+29 vs 384+ 19, P＜0.01). The serum VEGF level inthe HAL group increased significantly as against that of thecontrol group (93 ng@ L-1 + 44 ng@ L-1 vs 55 ng@ L-1 + 19 ng@ L-1,P＜ 0.05). The expression of VEGF and MMP-1 mRNA in thetumor tissue of the HAL group increased significantlycompared with that of the control and the laparotomy controlgroups ( P ＜ 0. 05). The blood perfusion data of the tumor,represented by the number of Hoechst 33 342 labeled calls,showed a good linear inverse correlation with the serumVEGF level ( r = -0.606, P ＜ 0. 05 ) and the expression ofVEGF mRNA in the tumor tissue ( r= -0.338, P＜ 0.01).CONCLUSION: Blockage of hepatic arterial blood supplyresults in decreased blood perfusion and increasedexpression of metastasis-associated genes VEGF and MMP-1of transplanted liver cancer in rats. Decreased bloodperfusion and hypoxia may be the major cause of up-regulated expression of VEGF.     

Portal hypertension and ascites in acute hepatitis: clinical, hemodynamic and histological correlations

We attempted to ascertain the mechanism of portal hypertension and ascites complicating acute hepatitis in 66 patients who underwent transvenous liver biopsy and measurement of hepatic venous pressure gradient. Increase in hepatic venous pressure gradient was related to the severity of acute hepatitis, as indicated by the significant correlation between the values for hepatic venous pressure gradient and serum bilirubin, serum albumin or coagulation factor V, and by its higher value in patients with, than in patients without, encephalopathy. Hepatic venous pressure gradient was higher in patients with, than in patients without, ascites (12.5 +/- 3.4 vs. 8.4 +/- 3.6 mmHg, respectively; p less than 0.001). No ascites was clinically detectable in the patients in whom hepatic venous pressure gradient was below 6 mmHg. We tested the hypothesis that sinusoidal collapse due to liver cell dropout was a major factor in portal hypertension. Semiautomatic determination of the fractional area of sinusoidal collapse on chromotrope-stained sections and automatic measurement of Sirius red-stained collagen fiber density were performed. Hepatic venous pressure gradient significantly correlated with fractional sinusoidal collapse area (r = 0.61, p less than 0.001) and with Sirius red-stained collagen fiber density (r = 0.43, p less than 0.01). We conclude that portal hypertension in the course of acute hepatitis is related to the severity of liver damage and is a major factor in the development of ascites. Portal hypertension is mainly determined by intrahepatic vascular space being reduced by the collapse of sinusoids.     

The acid-labile subunit of the ternary insulin-like growth factor complex in cirrhosis: relation to liver dysfunction

BACKGROUND/AIMS: In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the level of ALS has not been described in relation to hepatic dysfunction. The aim of the present study was therefore to measure circulating and hepatic venous concentrations of ALS in relation to hepatic function and the IGF axis. METHODS: Twenty-five patients with cirrhosis (Child class A/B/C:5/10/10) and 30 controls with normal liver function were studied. During a haemodynamic investigation, blood samples were collected from the hepatic vein and femoral artery, and the plasma concentrations of ALS, IGF-I and IGFBP-3 were determined. RESULTS: Hepatic venous and arterial concentrations of ALS were significantly decreased in the cirrhotic patients compared with the controls (-69% and -68%, respectively, both p<0.001). IGF-I and IGFBP-3 were similarly decreased in the cirrhotic patients (-51%,p<0.001). A significant hepatic extraction of ALS was found in the controls (6%, p<0.01) and in the cirrhotic patients (8%, p=0.08). ALS correlated significantly with indicators of liver dysfunction, including the Child-Turcotte score (r=-0.69, p<0.0001), IGF-I (r=0.82, p<0.0001) and IGFBP-3 (r=0.74, p<0.0001). CONCLUSIONS: Circulating and hepatic venous ALS are decreased in patients with cirrhosis with significant relations to liver dysfunction and other components of the IGF complex. A small hepatic extraction was found in controls, which suggests extrahepatic production of ALS. Future studies should focus on organ-specific removal of ALS.     

Villous motility: relationship to lymph flow and blood flow in the dog jejunum

Villous contraction frequency, lymph flow, blood flow, and arteriovenous oxygen difference were measured in dog jejunum. Venous pressure elevation and plasma dilution were used to increase capillary fluid filtration. Both perturbations produced concomitant increases in villous contraction frequency and lymph flow. A highly significant correlation (r = 0.83, p less than 0.001) was obtained between villous contraction frequency and lymph flow. This finding, coupled with the observation that stimulation of net fluid absorption increases villous contraction frequency, suggests that villous motility is increased by a myogenic response elicited by increments in interstitial fluid pressure. In another series of experiments local arterial pressure was reduced in 20-mmHg steps from 120 to 20 mmHg. Although blood flow fell proportionately to arterial pressure, villous contraction frequency and oxygen uptake were maintained at a normal level when arterial pressure was between 120 and 60 mmHg. Villous motility and oxygen consumption fell progressively as arterial pressure was reduced below 60 mmHg. This observation indicates that ischemia does not alter villous contraction frequency unless blood flow is reduced below the level necessary to maintain normal tissue oxygenation.