Hypermetabolic state, hepatocyte expansion, and liver blood flow: an interaction triad in alcoholic liver injury

Comparison of liver hemodynamics according to doppler ultrasonography in alcoholic patients subtyped by Cloninger classification and non-alcoholic healthy subjects

BACKGROUND

The aim of this study was to search for morphological and hemodynamic changes in hepatic and splanchnic vasculature in alcoholic patients without the signs of hepatic damage and subtyped by Cloninger classification by means of sonography, and compare the subtypes among themselves and with nonalcoholic healthy subjects.

METHODS

Thirty alcohol dependent patients and 30 healthy subjects with no alcohol problem or hepatic impairment were included in the study. Patients were subtyped by Cloninger classification and all patients were evaluated by gray-scale and spectral Doppler ultrasound. The diameter of the portal vein, portal venous velocity, peak systolic and end diastolic velocities of hepatic and superior mesenteric arteries were assessed. RI, PI and systolic/diastolic velocity ratios were also calculated.

RESULTS

Portal vein diameter (PV diameter), portal vein cross sectional area (PV area), portal vein velocity (PV PSV), hepatic artery peak systolic velocity (HA PSV), hepatic artery end diastolic velocity (HA EDV), hepatic artery resistive index (HA RI), hepatic artery pulsatility index (HA PI), and systolic/diastolic velocity ratios (HA S/D), superior mesenteric artery peak systolic velocity (SMA PSV), superior mesenteric artery end diastolic velocity (SMA EDV), superior mesenteric artery resistive indices (SMA RI), pulsatility index (SMA PI), and systolic/diastolic velocity rates (SMA S/D) showed no significant difference among the groups (P > 0.01). Although there is no significant difference in PV PSV, HA PSV, SMA PSV, SMA EDV values between the groups, mean values of Type II alcoholics is greater than other groups. Portal vein cross-sectional area was greater in alcoholic patients (Type I, II and III) compared to the control group (P = 0.000). Portal vein velocity, hepatic artery peak systolic and end diastolic velocity, superior mesenteric artery peak systolic and end diastolic velocity were significantly greater in alcoholic patients than in the control group (P < 0.001). No statistical difference was detected between other parameters evaluated.

CONCLUSION

In alcohol dependent patients, some hemodynamic and morphologic changes occur in hepatic and splanchnic circulation, even before the signs of hepatic damage develop, which can be detected by means of Doppler and gray-scale sonography. But as there is no significant difference between the Doppler ultrasonographic findings among alcoholics subtyped by a Cloninger classification, which is a clinical classification, it suggests that psychiatric classification doesn't show any correlation with biological parameters, and because of this Cloninger classification a psychiatric classification cannot be considered as a characteristic determinative factor in the prognosis of hepatic disorder due to alcohol use. However, higher values of Type II alcoholics can be attributed to the longer alcohol intake of this subtype.

Doppler and gray-scale ultrasound evaluation of morphological and hemodynamic changes in liver vascualture in alcoholic patients

OBJECTIVE

The aim of this study is to search sonographically for morphological and hemodynamic changes in hepatic and splanchnic vasculature of alcoholic patients having no signs of hepatic damage, and compare these with normal healthy subjects.

METHODS

Thirty alcohol-dependent patients and 30 control subjects with no alcohol problem or hepatic impairment were included in the study. All patients were evaluated by gray-scale and spectral Doppler ultrasound. The diameter of the portal vein, portal venous velocity, peak systolic and end diastolic velocities of hepatic and superior mesenteric arteries were assessed. RI, PI and systolic/diastolic velocity ratios were also calculated.

RESULTS

Portal vein cross-sectional area was greater in alcoholic patients compared to control group (P = 0.0012). Portal vein velocity, hepatic artery peak systolic and end diastolic velocity, superior mesenteric artery peak systolic and end diastolic velocity were significantly greater in alcoholic patients than in control group (P < or = 0.001). No statistically significant difference was detected between other parameters evaluated.

CONCLUSION

In alcohol-dependent patients, some hemodynamic and morphologic changes occur in hepatic and splanchnic circulation, even before the signs of hepatic damage develop. These changes can be detected by means of Doppler and gray-scale sonogrsphy.

In vivo monitoring of hepatic oxygenation changes in chronically ethanol-treated rats by functional magnetic resonance imaging

In this study, functional magnetic resonance imaging (fMRI) was used to evaluate in vivo hepatic oxygenation changes in chronically ethanol (CE)-treated and pair-fed (PF) control rats. Male Wistar rats were pair-fed an all-liquid diet containing 36% of total calories as either ethanol or dextrin-maltose for 8 weeks. The rats were initially examined under normoxic conditions, and then subjected to 100% oxygen (hyperoxia), 10% oxygen (hypoxia), 5% carbon dioxide (hypercapnia), or an acute dose of ethanol (1.4 g/kg bw intraperitoneally). A T(2)-weighted spin-echo sequence, which may be more selective for sinusoidal (capillary bed) changes, was performed before, during, and after the four challenges. During hyperoxia, both the CE and PF rats showed a statistically significant increase in signal intensity (22% +/- 5% and 48% +/- 6%, respectively, P < 0.05) relative to normoxia, while hypoxic challenge decreased the signal intensity (9% +/- 4%, p>0.05 and 15% +/- 3%, P < 0.05, respectively). The hypercapnic challenge, which causes vasodilation, resulted in a small increase in signal intensity in CE-fed rats (5% +/- 3%, P > 0.05) and a significant increase in the PF rats (15% +/- 4%, P < 0.05), again consistent with expected changes in deoxyhemoglobin. With all three physiological challenges, the degree of change was less in CE rats compared to PF controls. An acute dose of ethanol that causes vasodilation also increased signal intensity, with no significant difference between the two groups. The signal intensity changes seen with fMRI were highly correlated with pulse oximeter readings (r(2) = 0.95; P < 0.05). In conclusion, fMRI was shown to be a good noninvasive indicator of tissue deoxyhemoglobin changes in the liver. In addition, fMRI was able to detect subtle, early effects of CE administration (manifested as an impaired ability of the liver to respond adequately to oxygenation challenges), consistent with microvascular dysfunction.

Comparison of prevalence for paraumbilical vein patency in patients with viral and alcoholic liver cirrhosis

OBJECTIVES

The patent paraumbilical vein (PUV) is a venous collateral that is often found in patients with cirrhosis and portal hypertension. It can be effectively demonstrated by conventional ultrasonography (US). We conducted this prospective study to elucidate the prevalence and etiology of PUV patency for cirrhotic patients.

METHODS

From August, 1997, to July, 1998, one of the authors (S.-N.L.) observed PUV patency for all cirrhotic patients during routine upper abdominal US examination. All cirrhotic patients diagnosed with portal hypertension were further analyzed. Portal hypertension was diagnosed by sonographic evidence of splenomegaly or ascites, or endoscopic varices. Cases presenting with hepatocellular carcinoma and sonographic evidence of prehepatic portal hypertension were excluded. Once a PUV patency with a diameter of > or = 3 mm was suspected based on conventional US, it was confirmed by color Doppler US. Of the 493 cirrhotic patients examined, 252 with portal hypertension and without hepatoma were enrolled in this study.

RESULTS

Significant PUV patency was detected in 11.1% of the enrolled patients (28 of 252). With univariate analysis, a significantly higher prevalence was demonstrated for alcoholic patients (p < 0.0001), whereas prevalence was relatively low for those with chronic hepatitis B or C infection (p = 0.0159). A trend toward increased prevalence was noted with Child-Pugh classification (p = 0.001). Furthermore, a higher prevalence was noted in younger cirrhotic patients (p = 0.0037). Alcoholism was still a significant factor despite adjustment of Child-Pugh classification using multiple logistic regression, (OR = 3.88, 95% CI = 1.34-8.55).

CONCLUSION

A significantly higher prevalence of PUV patency was demonstrated for patients with alcohol-induced liver cirrhosis in comparison to those with postviral cirrhosis.

Liver function in cirrhotic patients in the euthyroid versus the hypothyroid state

We recently showed that some decrease in thyroid hormone blood levels can effectively and significantly prevent the development of cirrhosis and fulminant hepatic failure and decrease portal pressure in three different rat models. This study was conducted to determine whether hypothyroidism has a beneficial effect over euthyroidism on patients with active liver cirrhosis of different etiologies. The medical files of hypothyroid patients with cirrhosis who were referred to the Tel-Aviv Medical Center between the years 1980 and 1995 were retrospectively evaluated. Of 3,528 patients with biopsy-proven cirrhosis and 4,738 hypothyroid patients who were identified, only 46 (25 female, 54%; mean age, 52.3 +/- 9.1) met the eligibility criteria. The patients suffered from cirrhosis (mean, 9.5 +/- 4.3 years; range, 4-23) and had hypothyroidism (mean, 12 +/- 6 years; range, 4-31). Most patients suffered from hypothyroidism of unknown etiology (85%), whereas the rest had hypothyroidism after surgical/iodine ablation of the gland. In the hypothyroid versus the euthyroid state, a significant negative correlation was found between thyroid-stimulating hormone blood levels and both functional and synthetic liver function tests (p < 0.001). A significant negative correlation was also found between thyroid-stimulating hormone blood levels and clinical deterioration manifested as bleeding varices, the development of ascites, and episodes of encephalopathy. We conclude that in patients with liver cirrhosis, the liver function in the hypothyroid state tend to be better than in the euthyroid state. A mild controlled decreased thyroid function may be beneficial for euthyroid cirrhotic patients.

Hepatic artery resistance in alcoholic liver disease

Patency and direction of flow in portal veins and their branches are generally assessed by duplex Doppler ultrasonography (DDUS), whereas few data are available on hepatic arterial hemodynamics. In this study, resistive (RI) and pulsatility indexes (PI) were calculated at DDUS in 21 controls, 22 chronic alcoholic patients without evidence of liver damage, 19 patients with acute alcoholic hepatitis (AAH), 30 patients with chronic viral hepatitis (CVH), 23 patients with alcoholic cirrhosis, and 22 patients with viral-related cirrhosis. Diagnosis was based on clinical and histological findings. Mean +/- SD RI was similar in controls and CVH patients (0.64 +/- 0. 02 and 0.66 +/- 0.04, respectively), significantly decreased in alcoholic patients without liver damage and AAH patients (0.61 +/- 0. 07 and 0.60 +/- 0.07) (P < .05), and significantly increased in patients with alcoholic (0.72 +/- 0.04) and viral-related cirrhosis (0.74 +/- 0.04) (P < .05). It was <0.60 in 9 of the 19 AAH patients (47%) and 11 of the 22 alcoholic patients without liver damage (50%), and >0.70 in 39 of the 45 cirrhotic patients (87%) and 12 of the 71 noncirrhotic patients pooled together (17%). A significant correlation was observed between RI and PI (r = .83; P < .05). The coefficients of variation for intraobserver variability were 6.3% +/- 5.1% for RI and 10.1% +/- 6.2% for PI, and the corresponding figures for interobserver variability were 5.2% +/- 3.5% and 9.3% +/- 4.6%. These findings support the existence of ethanol-related hepatic arterial vasodilation in AAH and alcoholic patients without liver damage. Progression of liver damage from AAH to cirrhosis profoundly impairs the hepatic responsiveness as a consequence of fibrosis with vascular distortion.

The formation and measurement of DNA neuroadduction in alcoholism. Case report

We present a case report of an intoxicated alcoholic driver who sustained fatal motor vehicle injuries. We subsequently quantified ethanol-derived acetaldehyde (ACE) DNA products in his brain, which may represent a major contributor to clinical alcoholic use and complications. Further, ACE DNA neuroadducts may indicate chronic exposure to alcohol, as demonstrated by 32P-prelabeled DNA and two-dimensional thin-layer chromatography. ACE and other unknown neuroadducts were evident in the histologically normal frontal, parietal, and caudate lobes. DNA neuroadduct formation was extensive and similar in three separate brain regions with normal histology. Contributing neuroadduction by chronic drug abuse is also possible, though the deceased's terminal acute blood screens for recent drug abuse were negative. The mechanism of alcohol neurotoxicity remains unknown, but biochemical nonenzymatic changes of DNA at the nucleic acid level (adduct formation) can alter gene function and stability. DNA neuroadduct detection may represent an important determinant in quantifying neurotoxicity from drug abuse or alcoholism in the absence of history, the presence of negative blood, tissue, and urine assays for recent drug and alcohol use, and the absence of neuropathology.

Interaction of ethanol and the organophosphorus insecticide parathion

Phosphorothioate insecticides such as parathion (O,O-diethyl-O-p-nitrophenyl phosphorothioate) undergo P450-dependent oxidative desulfuration, leading to both activation and detoxification of these compounds. Consequently, alterations in P450-dependent oxidative desulfuration may affect the acute toxicities of these insecticides. In the present study, pretreatment of mice with 15% ethanol in the drinking water for 6 days antagonized the acute toxicity of parathion, but not its toxic metabolite paraoxon (O,O-diethyl-O-p-nitrophenyl phosphate), suggesting that ethanol affected the oxidative desulfuration of this insecticide. The presence of ethanol within hepatic microsomal incubations did not alter the P450-dependent formation of paraoxon (activation) and p-nitrophenol (detoxification), although p-nitrophenol levels were increased in the presence of ethanol as a result of inhibition of its biotransformation to 4-nitrocatechol by CYP2E1. Ethanol exposure reduced hepatic pyruvate levels, but had no effect on levels of lactate, isocitrate, alpha-ketoglutarate, and malate. Calculation of cytosolic NAD+/NADH and cytosolic NADP+/NADPH redox ratios did not reveal any detectable difference in redox state between control and ethanol-treated mice. Since ethanol did not alter directly the P450-dependent activation or detoxification of parathion, and did not decrease NADPH levels, ethanol's antagonism of the acute toxicity of parathion may result from reduced availability of O2.

Ethanol increases hepatocyte water volume

Mouse hepatocytes respond to osmotic stress with adaptive changes in transmembrane potential, Vm, such that hypotonic stress hyperpolarizes cells and hypertonic stress depolarizes them. These changes in Vm provide electromotive force for redistribution of ions such as Cl-, and this comprises part of the mechanism of hepatocyte volume regulation. We conducted the present study to determine whether ethanol administered in vitro to mouse liver slices increases hepatocyte water volume, and whether this swelling triggers adaptive changes in the Vm. Cells in mouse liver slices were loaded with tetramethylammonium ion (TMA). Changes in hepatocyte water volume were computed from measurements with ion sensitive microelectrodes of changes in intracellular activity of TMA (a1TMA) that resulted from water fluxes. Ethanol (70 mM) increased hepatocyte water volume immediately, and this peaked at 17% by 7 to 8 min, by which time a plateau was reached. Liver slices also were obtained from mice treated 12 hr prior with 4-methylpyrazole (4 mM). The effect of ethanol on their hepatocyte water volume was identical to that from untreated mice, except that the onset and peak were delayed 2 min. Hepatocyte Vm showed no differences between control or ethanol-treated cells during the course of volume changes. In contrast, hyposmotic stress, created by dropping external osmolality 50 mosm, increased Vm from -30 mV to -46 mV. Ethanol did not inhibit this osmotic stress-induced hyperpolarization, except partially at high concentrations of 257 mM or greater. We infer that ethanol-induced swelling of hepatocytes differs from that resulting from hyposmotic stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term treatment of alcoholic liver disease with propylthiouracil. Part 2: Influence of drop-out rates and of continued alcohol consumption in a clinical trial

Although propylthiouracil has previously been shown to reduce the risk of mortality in alcoholic liver disease by 60%, generalized use of propylthiouracil for this condition has not occurred. Additional data are therefore presented on four aspects to provide a better assessment of its therapeutic effectiveness. First, the characteristics and the prognosis of dropouts were virtually identical in both the drug and placebo groups. Also the methodology and analysis employed, were designed to control for dropouts, thus providing an accurate interpretation of the outcome. Secondly, since 97% of the patients continued to drink, abstinence was not a precondition for the beneficial effect of propylthiouracil. However, the beneficial effect was observed most clearly in those patients who continued to drink at lower levels, whereas lower level drinking per se did not afford protection in placebo patients. Thirdly, serious side effects or clinical hypothyroidism occurred extremely rarely in these patients, many of whom have now received propylthiouracil for over 4 years. Fourthly, we discuss why the outcome in long-term clinical trials in alcoholic liver disease cannot be compared with effects observed in clinical trials lasting only a few weeks. Journal of Hepatology.

Effect of propylthiouracil on the ethanol-induced increase in liver oxygen consumption in awake rats

It has been postulated that the beneficial effects of the antithyroid drug propylthiouracil in the treatment of alcoholic liver disease depend primarily on the action of propylthiouracil in suppressing the increase in hepatic oxygen consumption induced by ethanol. The evidence for this effect of propylthiouracil is derived from studies in which liver oxygen consumption has been determined in in vitro preparations. In our study the effects of ethanol and propylthiouracil on liver oxygen consumption were assessed in vivo in an unrestrained and unanesthetized rat model, where liver blood flow and hepatic vein and portal vein oxygen content can be measured. Data show that the liver oxygen consumption increased in rats treated with ethanol-containing liquid diets for 4 to 6 wk, both on withdrawal of alcohol (30%, p < 0.01), and after readministration of ethanol (50%, p < 0.01). Single-dose ethanol administration increased portal tributary blood flow without affecting hepatic arterial blood flow in both controls and rats withdrawn from long-term ethanol treatment. Long-term ethanol administration per se had no effect on portal tributary blood flow; however, hepatic arterial blood flow was increased by 38% (p < 0.01). Treatment with propylthiouracil for 5 days resulted in complete suppression of the increase in liver oxygen consumption induced by long-term ethanol administration. Propylthiouracil treatment also attenuated the increase in portal tributary blood flow after the administration of a single dose of ethanol. These determinations were made 24 hr after the last dose of propylthiouracil.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral trauma and alcohol abuse

We report results of clinical examinations, computed tomography, quantitative electroencephalography (QEEG), and cerebral blood flow measurements performed on a series of 56 consecutive brain injury patients including 15 alcohol abusers and 41 non-alcoholic subjects. Greater volumes of intracranial haemorrhage were noted in the alcoholics for a similar severity of injury and local brain atrophy became more pronounced in them during a follow-up of 1 year. After this time, the third ventricle width, distance between frontal horns, the sum of lateral ventricle dimensions and cortical sulci were all markedly larger in the alcoholics. The QEEG results also indicated a weaker improvement in the alcoholics. The cerebral blood flow at the site of the injury was initially slow in the alcoholics when compared to the contralateral region of the other hemisphere, although these differences disappeared during the follow-up. Permanent occupational disability was also found to be associated with pretraumatic alcohol abuse. The findings indicate that ethanol abuse is not only commonly associated with cerebral trauma but is also a risk factor for a more severe brain damage following the injury.

The effects of chronic ethanol consumption on the intact rat liver studied by in vivo 31P NMR spectroscopy

In vivo 31P nuclear magnetic resonance (NMR) spectroscopy provides unique opportunities to study the biochemistry of an organ within the intact animal in a totally non-invasive way. We have used in vivo and in vitro 31P NMR spectroscopy to study steady state changes in the major phosphorus-containing metabolites of the rat liver in control and chronically ethanol-treated rats. Chronic (4 month) ethanol treatment caused a statistically significant increase in the inorganic phosphate and phosphodiester resonances of rat liver in in vivo 31P NMR spectra relative to pair-fed control rats. Phosphomonoester and adenosine 5'-triphosphate resonances, as well as intracellular pH, were not appreciably altered. The effects of chronic ethanol treatment were particularly apparent in the response of the liver to a metabolic challenge of glycerol. Glycerol is phosphorylated almost exclusively in the liver and metabolized predominately via glycolysis and gluconeogenesis. Our in vivo 31P NMR results after administration of glycerol showed a significant increase in the phosphomonoester resonance in the liver of chronic ethanol-treated rats but not for their pair-fed controls. In vitro 31P NMR studies of perchloric acid extracts of liver showed that the increase was due to an accumulation of sn-glycerol 3-phosphate. This effect is due to the NAD(+)-dependent glycerol 3-phosphate dehydrogenase step being inhibited in the chronic ethanol-treated rats. This glycerol test may be useful in assessing the ability of the liver to rapidly regenerate NAD+ in situ and may be a more sensitive indicator of redox imbalance than steady state ratios of redox pairs (e.g., lactate/pyruvate).

The role of continued drinking in loss of portal perfusion after distal splenorenal shunt

Fifty percent of patients with alcoholic cirrhosis who undergo distal splenorenal shunting for variceal bleeding lose portal perfusion within 1 year. Although it was previously considered that this loss of portal flow was irrevocable, the present study shows that with resolution of alcoholic hepatitis, portal perfusion can be restored. A 34-year-old patient with alcoholic liver disease and a distal splenorenal shunt lost portal perfusion 1 year after the operation. He had continued to drink alcohol and had high sinusoidal pressure. Following forced abstinence over the next 2 years, his sinusoidal pressure fell, liver volume decreased, results of liver biopsy improved, and portal perfusion was restored. Shunt patency was documented, and the same collaterals from the portal vein to the shunt could still be visualized as had been seen when portal flow was absent. Restoration of portal perfusion was attributed to decreased intrahepatic resistance secondary to abstinence from alcohol. A return to drinking in the next 9 months led to alcoholic hepatitis and once again loss of portal perfusion. This study places emphasis on increased intrahepatic resistance rather than the development of portal-to-shunt collaterals as important in the loss of portal flow in such patients.

Effects of chronic ethanol consumption on the synthesis of polypeptides encoded by the hepatic mitochondrial genome

Liver mitochondria from rats fed ethanol chronically demonstrate an impaired ability to incorporate [35S]methionine into polypeptide products in vitro. This ethanol-induced effect on mitochondrial translation in vitro could not be attributed to significant differences in the methionine precursor pool sizes of ethanol and control mitochondria or to the acute effects of residual ethanol. The observed reduction of radiolabeled methionine incorporation into mitochondrial gene products of ethanol mitochondria in vitro reflects a decrease in the synthesis of all the mitochondrial gene products. However, the percentage of total radiolabel incorporated into each gene product is unaffected by ethanol, suggesting an ethanol-induced coordinate depression of mitochondrial protein synthesis. Moreover, SDS-PAGE and densitometry of submitochondrial particles from ethanol-fed and control rats demonstrated that the steady-state concentration of each of the mitochondrial gene products is decreased in ethanol-fed rats. This reduction of the steady-state concentration of the mitochondrial gene products may be related to the observed depressions of oxidative phosphorylation activities associated with hepatic mitochondria from ethanol-fed rats.

Alterations in splanchnic blood flow following chronic ethanol exposure

The purpose of these experiments was to determine whether or not tolerance develops to the effect of 3.0 g/kg ethanol on total and regional splanchnic blood flow in male Wistar rats. The animals were given the Lieber-DeCarli liquid diet containing ethanol for 10 days; ethanol-fed animals were withdrawn 24 hr prior to experiments. Regional blood flow and cardiac output (CO) were measured by the reference microsphere technique after an intraperitoneal injection of 3.0 g/kg of ethanol. Acute ethanol administration produced early nonsustained increases in portal vein blood flow in animals fed ethanol for 10 days and withdrawn for 24 hr and in control animals. However, after chronic exposure to ethanol, the pattern of increase in blood flow in response to ethanol in the splanchnic organs was different between the ethanol-fed and control groups. Increases in portal vein flow in control groups were due to concomitant increases in small intestinal, colonic, and cecal blood flow while the increase in the ethanol-fed group was due to a rise in small intestinal and stomach blood flow. The increase in stomach blood flow that occurred in the animals treated chronically with ethanol may be viewed as a conditioned response to ethanol, since this was not found in the control group. These results, demonstrate that the pattern of increase in blood flow in the splanchnic organs produced by an acute dose of ethanol depends on the animal's previous exposure to ethanol.

Hepatic circulation: potential for therapeutic intervention

In recent years, knowledge of the physiology and pharmacology of hepatic circulation has grown rapidly. Liver microcirculation has a unique design that allows very efficient exchange processes between plasma and liver cells, even when severe constraints are imposed upon the system, i.e. in stressful situations. Furthermore, it has been recognized recently that sinusoids and their associated cells can no longer be considered only as passive structures ensuring the dispersion of molecules in the liver, but represent a very sophisticated network that protects and regulates parenchymal cells through a variety of mediators. Finally, vascular abnormalities are a prominent feature of a number of liver pathological processes, including cirrhosis and liver cell necrosis whether induced by alcohol, ischemia, endotoxins, virus or chemicals. Although it is not clear whether vascular lesions can be the primary events that lead to hepatocyte injury, the main interest of these findings is that liver microcirculation could represent a potential target for drug action in these conditions.

Effect of ethanol on splanchnic hemodynamics in awake and unrestrained rats with portal hypertension

Alcoholic liver disease is frequently accompanied by portal hypertension. We have previously shown that alcohol intake in awake, unrestrained rats is followed by an increase in portal tributary blood flow. In this study, the effect of ethanol on splanchnic hemodynamics in rats with portal hypertension was analyzed. Portal hypertension was induced by partial ligation of the portal vein. This procedure resulted in an increase in portal tributary and hepatic arterial blood flows compared to sham-operated animals. Ethanol (2 gm per kg, oral) increased portal tributary blood flow in both sham-operated and portal vein-ligated rats (sham + water = 37.6 +/- 1.4; sham + ethanol = 63.1 +/- 1.9; p less than 0.01; partial portal vein stenosis + water = 53.2 +/- 3.3; partial portal vein stenosis + ethanol = 69.5 +/- 2.2 ml.kg-1.min-1; p less than 0.01). In sham-operated rats, hepatic artery blood flow was unchanged following ethanol (sham + water = 6.6 +/- 0.7; sham + ethanol = 7.1 +/- 1.0 ml.kg-1.min-1), whereas in portal vein-ligated rats, flow was increased (partial portal vein stenosis + water = 13.7 +/- 1.4; partial portal vein stenosis + ethanol = 19.8 +/- 1.1 ml.kg-1.min-1; p less than 0.025). The adenosine receptor blocker 8-phenyltheophylline suppressed only the ethanol-induced increase in both portal tributary and hepatic artery blood flows in portal vein-ligated rats. The increases in hepatic artery and portal tributary blood flows observed in portal vein-ligated rats without ethanol were not influenced by 8-phenyltheophylline.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between fatty liver and subsequent development of necrosis, inflammation and fibrosis in experimental alcoholic liver disease

Rats fed a diet varying in the amount of fat, infused with ethanol, were studied to determine the relationship among diet, degree of fatty liver, and development of necrosis, inflammation, and fibrosis. Three groups of experimental animals, male Wistar rats, were fed diets containing 25% fat, 35% fat, and 32% fat with low protein. Morphologic assessment of liver injury was performed monthly by obtaining liver biopsies. The greatest degree of fatty infiltration at 1 month was seen in the high fat-low protein group, the mean fat score (3.8 +/- 0.37) was significantly higher than in the other two groups (P less than 0.05 and P less than 0.01). When the subsequent development of necrosis, inflammation, and fibrosis was related to the degree of fatty infiltration at 1 month, a significant relationship was seen between the number of animals developing these pathologic lesions and the severity of fatty liver. Our results show that the degree of fatty infiltration of the liver, influenced by the dietary intake of both fat and protein, is related to the subsequent development of necrosis, inflammation, and fibrosis in our intragastric feeding model for alcoholic liver disease.

Effects of propylthiouracil and methimazole on splanchnic hemodynamics in awake and unrestrained rats

The treatment of alcoholic liver disease with propylthiouracil is based on its effect of suppressing the ethanol-induced increase in hepatic oxygen consumption. It has been postulated that liver necrosis ensues when the increase in oxygen demand by the liver exceeds oxygen delivery to this organ. Data are now presented which show that propylthiouracil also increases portal blood flow in awake, unrestrained rats. Liver blood flow was determined using the labeled microsphere technique in rats at various intervals (0.25, 0.5, 1.0, 3.0, 6.0 and 24 hr) after oral propylthiouracil (50 mg per kg). Administration of propylthiouracil (dose range: 6.25 to 100.0 mg per kg) produced a dose-dependent increase in portal blood flow when given either orally or intraarterially. Maximal flows were obtained with 50 mg per kg (controls = 37.8 +/- 1.5, oral propylthiouracil = 50.7 +/- 2.2 ml.kg-1.min-1). This increase in portal blood flow was accompanied by a decrease in preportal vascular resistance (controls = 2.61 +/- 0.16; propylthiouracil, 50 mg per kg = 1.79 +/- 0.09 mmHg per ml.kg-1.min-1). These effects were correlated with the plasma concentrations of propylthiouracil (r = 0.67, n = 68, p less than or equal to 0.001). The effect of oral propylthiouracil (50 mg per kg) on portal blood flow started at 0.5 hr and lasted for 6 hr after administration, whereas total liver blood flow was increased for 3 hr. Oral propylthiouracil (50 mg per kg) for 5 days resulted in a 53% increase in thyroid weight, an 85% reduction in 125I thyroid uptake and a 74% decrease in serum thyroxine concentration.(ABSTRACT TRUNCATED AT 250 WORDS)