Different effects of carbon tetrachloride on carcinogen-induced hepatocellular carcinoma and normal liver of the rat: lowered lipid peroxidation and accelerated necrosis in cancer

To investigate molecular responses to lipid peroxidative stimuli in neoplastic cells, lipid peroxidation was induced in liver of rats bearing 3'-methyl-4-dimethylaminoazobenzene-induced hepatocellular carcinoma by injecting a high dose of carbon tetrachloride (CCl4), a strong lipoperoxidative reagent. Normal rat livers with or without CCl4 treatment served as controls. CCl4 administration markedly provoked fatty metamorphosis, visualized by oil red O staining, in normal livers while minimal fatty changes were seen in hepatocellular carcinomas, where necrosis was often observed instead. After CCl4 treatment, the thiobarbituric acid values (representing levels of lipid peroxides in the tissue) were increased two-fold in the untreated normal liver, but were unchanged in the cancer tissue. Levels of vitamin C, an acutely reactive antioxidant, measured by high-performance liquid chromatography were not influenced by the CCl4 injection in the cancer tissue whereas a significant decrease was evident in normal livers. The total fatty acid content, measured by gas chromatography, was significantly lower in the cancer tissue than in the normal liver while the ratio of polyunsaturated fatty acids (PUFAs) in total fatty acids was little changed. Resistance of hepatocellular cancer cells to fatty metamorphosis and their susceptibility to necrosis induced by free radicals may be due to the paucity of the target PUFAs in their cell membrane fraction, resulting in low levels of lipid peroxides. Peroxidation of PUFAs might act as a "shock absorber" against free radical-induced toxic cell death in normal cells.

Incidental microvesicular steatosis due to valproic acid anticonvulsant therapy

Valproic acid has been implicated in at least 100 cases of fatal acute liver failure. Most cases have occurred in patients less than 10 yr old; however, at least seven have involved adults. Microvesicular steatosis has been uniformly observed, but its incidence in less severe liver disease and in asymptomatic patients receiving valproate is unknown. We report two patients receiving maintenance valproate, one with resolving acute hepatitis C and the other with chronic persistent hepatitis C, with incidental microvesicular steatosis demonstrated on oil-red O stains. We conclude that microvesicular steatosis does not necessarily signify hepatotoxicity in patients on chronic valproic acid, and should not lead to discontinuation of the drug until other causes of acute or chronic liver disease have been excluded.

Massive hepatic enlargement with fatty change associated with ketoconazole

Several forms of hepatic toxicity have been described with the antifungal agent ketoconazole. We report a case of massive liver enlargement with fatty infiltration presenting as gastric compression. This occurred in a young woman with AIDS taking ketoconazole as maintenance therapy for cryptococcal meningitis. This is the first reported case of ketoconazole causing fatty change in the liver.

[Morphological evaluation of toxic effect of kartolin-2]

Lipid dystrophy, rapid reduction of RNA and glycogen content in the liver of all experimental rats, developing as a result of acute kartolin-2 poisoning testify to an expressed hepatotropic effect of the substance. Alongside with the processes of parenchymal liver cell damage the signs of intracellular regenerating processes--increase of the size of hepatocytes nuclei are detected. Liver protein metabolism disturbances are observed following exposure to kartolin-2 in the acute experiment. Chronic exposure to kartolin-2, and, specifically to its preparation form in the dose 1/100 LD50 cause lipid infiltration, reduction of histochemical indicators of liver glycogen, and RNA content. No-effect doses of kartolin-2 have been determined.

Carnitine metabolism in rats with 4-pentenoic acid induced fatty liver

The effects of 4-pentenoic acid, a chemical claimed to induce fatty liver morphologically similar to that seen in Reye's syndrome, on carnitine metabolism and on hepatic histology were studied. Male Wistar rats were injected with 50 mg/kg doses of 4-pentenoic acid intraperitoneally every four hours over a period of 82 hours. Control rats received a similar volume of saline instead. The animals were then sacrificed at 82 hours. Liver, serum and urine were collected and stored in dry ice. The concentrations of free, acyl-, and total (free plus acyl) carnitines determined in serum were found to be significantly decreased in the rats which had received 4-pentenoic acid, while the concentrations of acyl- and total carnitines were significantly elevated in urine. In the liver tissue, the concentrations of short chain- and medium chain-acylcarnitines tended to be elevated, but the differences were not statistically significant. These results suggest that enhanced acylation of free carnitine with metabolites of 4-pentenoic acid, and excretion of the resulting acylcarnitine into urine are likely mechanism of the 4-pentenoic acid-induced hypocarnitinemia. Liver histology revealed marked fatty change with minute fat droplets similar to those observed in Reye's syndrome, and very slight alteration in mitochondrial configuration.

Assessment of Kupffer cell function in rats with chronic liver injury caused by CCl4

Kupffer cell function was assessed by using scintigraphy to evaluate the turnover of a metabolizable tracer (99mTc-millimicrosphered albumin). The organ uptake rate of the tracer, and new parameters concerned with the degradative functions of Kupffer cells obtained from analysis of the excretion phase of the hepatic time-uptake rate curve, were measured in rats with two different types of chronic liver damage induced by carbon tetrachloride (fatty liver group and liver cirrhosis group). The hepatic uptake rate in chronic liver injury decreased, while in contrast the splenic and pulmonary uptake rates increased. A particularly high uptake by the lungs was observed. The data demonstrated a reduced phagocytic activity of the Kupffer cells in rats with chronic liver injury. The new parameters concerned with Kupffer cell degradative function; i.e. the excretion rate (K) and the degradation rate in the first 60-min (D60), were markedly decreased even in the early stage of chronic liver injury. The data showed that the impairment of Kupffer cell degradative function occurred even earlier in liver damage than impairment of the phagocytic activity, so that the K value and the D60 value were the more sensitive indicators of Kupffer cell function.

Estrogen induction of fatty liver in dairy cattle

Two trials were conducted to determine if estrogen contributes to development of fatty liver in dairy cattle. During trial 1, eight late lactation, nonpregnant cows were assigned to 0 or 15 mg estradiol-17 beta benzoate/d treatment. Days 1 to 3 of the trial were for baseline measurements, and treatments were given from d 4 to 21; on d 20 and 21 animals were fasted. Short-term feed deprivation resulted in increased plasma FFA concentrations and rapid accumulation of triglyceride into liver tissue obtained by biopsy. During starvation, plasma FFA concentration and liver triglyceride content were lower for cows receiving the estradiol-17 beta treatment relative to cows receiving control treatment. Very low density lipoprotein concentration in blood increased dramatically in three of four animals during estradiol-17 beta administration. Because of the decrease in milk production during estradiol-17 beta treatment, it was not known whether this represented a decrease in very low density lipoprotein clearance from blood or reflected a lipotropic response to estradiol-17 beta. Therefore, a second trial was conducted employing nonlactating cows, and control and estradiol-17 beta-treated animals were pair fed. The trial was 33 d with d 1 to 3 for baseline measurements, and treatments were administered from d 4 to 33. All animals were starved from d 19 to 23. Estradiol-17 beta increased hepatic lipid and triglyceride accumulation and plasma very low density lipoprotein concentration during starvation. Plasma FFA concentration was also increased by estradiol-17 beta during this time; therefore, a direct or indirect effect of estrogen on hepatic lipid metabolism could not be delineated.

Fatty liver change as a result of hepatic artery infusion chemotherapy

Direct hepatic arterial infusion of floxuridine (FUDR) (Roche Laboratories, Division of Hoffman-LaRoche Inc., Nutley, NJ, U.S.A.) has been used extensively in the treatment of metastases of colorectal tumors to the liver. The effectiveness of infusion and tolerance of the chemotherapy has been improved utilizing a totally implantable infusion pump delivery system. However, unequal distribution of drug infusion may occur to different parts of the liver parenchyma as demonstrated by hepatic arterial infusion scintigraphy (HAPS). We present a case of such unequal perfusion in which fatty metamorphosis of the liver occurred in the overperfused liver segment after FUDR therapy. The liver parenchymal changes were followed by serial computerized tomography scans and proven by biopsy during a minilaparotomy. Serial HAPS examinations show redirection of subsequent infusion to the opposite liver lobe due to parenchymal damage and vascular sclerosis. The importance of uniform liver perfusion and a rare dose-related effect of FUDR on liver parenchyma are thereby demonstrated.

Modulation of the course of CCl4-induced liver injury by the anti-calmodulin drug thioridazine

Thioridazine (TDZ) administration to rats (50 mg/kg i.p.) 6 or 10 h after CCl4 treatment (1 ml/kg in olive oil i.p.) partially prevented necrogenic effects of this compound at 24 h but not at 72 h. TDZ did not have inhibitory effects on CCl4 activation, covalent binding (CB) of reactive metabolites to cellular constituents or CCl4-induced lipid peroxidation (LP). Moreover, TDZ had enhancing effects on both LP and CB. TDZ was able to increase protein and phospholipid synthesis and slightly but significantly enhanced protein but not phospholipid degradation in livers from control rats. TDZ administration decreased calcium liver content in CCl4-poisoned animals but did not change the intensity of CCl4-induced fatty liver. TDZ lowered body temperature in CCl4-treated animals during the 24 h observation period. These results and previous studies from our laboratory suggest calcium and calmodulin (CaM) participation in the CCl4 necrogenic effects on the liver but not in the hepatotoxin-induced fatty liver. TDZ-lowering effects on body temperature might also be a determinant in the delaying effects of this drug on the onset of CCl4-induced necrosis. Present experiments did allow discrimination between these two or other possible mechanisms for TDZ modulation effects.

[Use of the stable nitrogen isotope 15N in assessing liver metabolism in hormonal contraception]

In 37 women with long-term use of oral contraceptives (average use 13.4 years) and 12 women who had not taken oral contraceptives for at least 5 years we determined the serum enzymes ALAT, ASAT, Gamma-GT and conducted the 15N-ammonium test as a marker of partial metabolic performance of the liver. In addition we studied total protein, protein fractions in the serum and haematologic parameter. 18 out of 37 women showed a morbid result in the 15N-ammonium test. In 4 of these 18 women morphological changes representing hepatic damage caused by contraceptives could be detected. On the average ALAT, Gamma-GT and 15N-ammonium test in both groups are clearly different. Because the enzymic levels are being in the normal range, only the 15N ammonium test enables to give a hepatotoxic evidence. It is possible to conclude that long-term use of oral contraceptives influences the liver metabolism.

Microvesicular steatosis of the liver

The term "microvesicular steatosis of the liver" refers to a variant form of hepatic fat accumulation whose histologic features contrast with the much more common macrovesicular steatosis. Microvesicular steatosis of the liver was originally described in association with conditions who share a number of biochemical and a limited number of clinical features: acute fatty liver of pregnancy, Reye's syndrome, Jamaican vomiting sickness, sodium valproate toxicity, high-dose tetracycline toxicity and certain congenital defects of urea cycle enzymes; they were thought to constitute an entity of "microvesicular fat diseases". In recent years the disease has been described in a wide variety of conditions: alcoholism, toxicity of several medications, delta hepatitis in South America and Central Africa, sudden childhood death, congenital defects of fatty acid beta oxidation, cholesterol ester storage disease, Wolman disease and Alpers syndrome. Not much is known regarding the pathogenesis of microvesicular steatosis but in many instances the primary defect could be a mitochondrial lesion, and inhibition of the mitochondrial beta oxidation of fatty acids has been the most frequently implicated defect. The different conditions associated with microvesicular steatosis are heterogenous in many aspects. Maintaining the concept of "microvesicular fat diseases" as a unique entity seems no longer justified.

The effect of L-carnitine supplementation in 4 pentenoic acid treated rats

The effects of prolonged administration (7 days) of 4 pentenoic acid (4PA, 20 mg/kg/day) or 4PA (20 mg/kg/day) with L-carnitine (200 mg/kg/day) on carnitine metabolism and morphological changes of liver mitochondria were assessed in rats. 4PA-treated rats showed hyperammonemia, decreased levels of blood glucose, free fatty acids and beta-OH-butyrate, and of free carnitine in serum, muscle and liver, increased excretion of acylcarnitine in urine, and enlarged mitochondria with microvesicular steatosis, when compared to saline-injected control rats, respectively. 4PA plus L-carnitine rats showed decreased levels of blood ammonia and increased levels of beta-OH-butyrate, compared to the 4PA group. On the other hand, the levels of free carnitine in serum and liver in rats treated with both 4PA and L-carnitine were increased, when compared to controls. The ratio of acylcarnitine to free carnitine excreted in urine in 4PA-treated rats was higher than that in either the control or 4PA plus L-carnitine group. The liver mitochondria in the 4PA plus L-carnitine group were the same as in the controls. The results suggested that the abnormal biochemical and morphological findings due to only 4PA may be relieved with L-carnitine supplementation.

High levels of acetaldehyde in nonalcoholic liver injury after threonine or ethanol administration

Acetaldehyde, a product of ethanol oxidation which forms adducts with proteins, has been incriminated in the pathogenesis of alcoholic liver injury. High serum antibody titers against acetaldehyde-protein adducts have been found not only in alcoholics but also in patients with nonalcoholic liver disease, suggesting a contribution of acetaldehyde derived from sources other than exogenous ethanol. To investigate the effect of liver injury on the removal and the production of acetaldehyde, we produced fibrosis and cirrhosis (by chronic administration of carbon tetrachloride) and fatty liver (with very small doses of dimethylnitrosamine) in rats. Endogenous blood acetaldehyde levels increased by 38% in rats with severe liver injury (p less than 0.005), but not significantly in rats with fatty liver. However, an i.v. load of threonine (a physiological source of acetaldehyde), in amounts equivalent to the daily intake of this amino acid, increased blood and hepatic acetaldehyde levels in the rats with both types of liver injury more than in controls. Threonine dehydrogenase and dehydratase activities, involved in the major pathways for threonine degradation in mitochondria and cytosol, respectively, were markedly decreased in rats with liver injury with a resulting increase in hepatic threonine concentration. Moreover, the threonine aldolase activity, which splits threonine into glycine and acetaldehyde, remained unaffected or even slightly increased. Liver injury was also associated with impaired mitochondrial functions, including a 10 to 23% decrease in acetaldehyde oxidation (depending upon the severity of the lesions). As a consequence, administration of ethanol (an exogenous source of acetaldehyde) resulted in striking elevations in the levels of acetaldehyde in carbon tetrachloride-treated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Liver disorder owing to estrogen therapy in prostatic cancer, examined histopathologically in six autopsy cases]

The parenchymal damage of the liver after estrogen therapy for prostatic cancer, mainly treated with diethylstilbestrol diphosphate (DES-DP), was studied in the six autopsied cases, herein. The parenchymal disorder of the liver was "nonalcoholic steatohepatitis", reported by Ludwig et al., and its degree of disorder was dependent upon the administered dose of estrogen. The acceptable total dose of DES-DP was supposed to be about 150 g at maximum, according to the various degrees of damage examined histopathologically in the six cases who were administered at total doses of DES-DP from 12.6 g to 619 g. Comparison of the histopathologic damage to the liver function tests performed within 10 days before death revealed that only the serum levels of cholinesterase (ChE) were abnormally decreased, suggesting its importance to predict the degree of "nonalcoholic steatohepatitis" by monitoring of ChE.

Tianeptine, a new tricyclic antidepressant metabolized by beta-oxidation of its heptanoic side chain, inhibits the mitochondrial oxidation of medium and short chain fatty acids in mice

Tianeptine is a new tricyclic antidepressant which is metabolized mainly by beta-oxidation of its heptanoic side chain. We determined the effects of tianeptine on the mitochondrial oxidation of natural fatty acids in mice. In vitro, tianeptine (0.5 mM) inhibited by only 32% the formation of beta-oxidation products from [1-14C]palmitic acid by hepatic mitochondria, but inhibited by 71% that from [1-14C]octanoic acid and by 51% that from [1-14C]butyric acid. The activity of the tricarboxylic acid cycle, assessed as the in vitro formation of [14C]CO2 from [1-14C]acetylcoenzyme A was decreased by 51% in the presence of tianeptine (0.5 mM). The inhibition of both beta-oxidation and the tricarboxylic acid cycle appeared reversible in mitochondria from mice exposed to tianeptine in vivo but incubated in vitro without tianeptine. In vivo, administration of tianeptine (0.0625 mmol/kg i.p.), decreased by 53 and 58%, respectively, the formation of [14C]CO2 from [1-14C]octanoic acid and [1-14C]butyric acid, but did not significantly decrease that from [1-14C]palmitic acid. After administration of high doses of tianeptine, however, formation of [14C]CO2 from [1-14C]palmitic acid became inhibited as well, transiently after 0.25 mmol/kg and durably (greater than 24 hr) after 0.75 mmol/kg i.p. Hepatic triglycerides were increased 24 hr after administration of 0.75 mmol/kg i.p. of tianeptine, but not after 0.25 mmol/kg i.p. Microvesicular steatosis of the liver was observed in some mice after 0.75 mmol/kg i.p., but not after 0.5 mmol/kg i.p. We conclude that tianeptine inhibits the oxidation of medium- and short-chain fatty acids in mice. Microvesicular steatosis, however, requires very large doses in mice (0.75 mmol/kg i.p., i.e. 600-times the oral dose in humans), and is therefore unlikely to occur in humans.

Acute, reversible hepatic failure associated with methotrexate treatment of rheumatoid arthritis

We describe 2 patients who developed reversible decompensated liver disease while taking pulse dosed methotrexate (MTX) for rheumatoid arthritis. One of the patients was available for biopsy and had chronic active hepatitis--a lesion not previously described with MTX. This appears to be a unique and unusual manifestation of MTX hepatotoxicity.

Liver disease associated with exposure to 1,1,1-trichloroethane

1,1,1-trichloroethane is a halogenated hydrocarbon solvent commonly used in industry because of its supposed lack of hepatotoxicity. Nonetheless, animal studies performed by several independent groups have shown the solvent to induce fat deposition, vacuolar degeneration, and centrilobular necrosis, changes similar to those seen after exposure to carbon tetrachloride, albeit of a much reduced magnitude, in animals exposed to the agent. Four patients with fatty liver disease whose work entailed substantial exposure to this agent were seen at the University of Pittsburgh (Pa). Based on this clinical experience, we believe that 1,1,1-trichloroethane should be reconsidered as an agent with potential hepatotoxicity in man.

Hypertension does not stimulate the development of hypercholesterolemia or fatty liver induced by a high cholesterol/cholate diet in rats

A high cholesterol/cholate diet induced hypercholesterolemia and fatty liver in both spontaneously hypertensive rats (SHR) and normotensive control rats (WKY). However, in contrast to previous concepts, the levels of cholesterol ester, triacylglycerol and phosphatidylcholine in plasma as well as triacylglycerol in liver were higher in WKY than in SHR fed a normal diet. The high cholesterol/cholate diet elevated the levels of plasma cholesterol, plasma cholesterol ester and hepatic triacylglycerol, and the extent of elevation was significantly higher in WKY than in SHR. Increases both in monoene/saturated ratios, an indication of elevated delta 9-desaturase activity, and in linoleate/arachidonate ratios, a possible indication of impaired desaturation-elongation activity, were observed in hepatic and plasma lipids of both strains fed the high cholesterol/cholate diet. The increases in monoene/saturated ratios were similar in both strains, but the increases in the linoleate/arachidonate ratios were higher for the plasma cholesterol esters of WKY than of SHR. The n-6/n-3 ratios of plasma and hepatic lipids were higher in WKY than in SHR throughout the experiments. These diet-induced changes observed in hepatic and plasma lipids were not reflected in the aortic lipids. Thus, hypertension per se does not promote the development of hyperlipemia and fatty liver induced by a high cholesterol/cholate diet. Our results also suggest that the metabolism of polyenoic fatty acids is different between SHR and WKY.

[The pathogenesis of toxic liver lesions in workers in phosphorus production]

Data of an examination of 600 workers of the phosphorus industry and experimental findings indicate that of major importance in the pathogenesis of toxic lesions of the liver in chronic intoxication with yellow phosphorus and its compounds are disorders of the fatty metabolism developing due to inhibition of oxidation-reduction processes.

[The diagnosis of drug-induced hepatopathies]

The present paper reports on the recent possibilities of diagnosis in iatrogenic diseases of the liver. The iatrogenic diseases of the liver are diagnosed with difficulty since no clinical, biological and histological pathognomonic criteria are known. The hepatic lesions appearing after drug intake are extremely various, including: hepatocellular necrosis, cholestasis, hepatic granuloma, perisinusoid fibrosis, steatosis, pseudoalcoholic lesions, vascular lesions and hepatic tumours. Clinical criteria, very important for the diagnosis, are based on: appearance of the disease, regression of symptomatology when the treatment is interrupted and recurrence when it is administered again. The biological criteria are not specific but they may indicate the drug etiology of a liver disease. Increase in the serum concentration of aminotransferases might be the only biochemical disturbance and it might be overlooked if not systematically investigated. The immunological tests suggested for diagnosis of iatrogenic liver diseases are numerous but only a few of them are specific. Histological criteria cannot identify, for sure, the drug etiology of the lesions. They may suggest the possibility of a drug induced cause and may help in establishment of a correct diagnosis.

Histopathologic findings in the liver of rheumatoid arthritis patients treated with long-term bolus methotrexate

Twenty-three patients with severe rheumatoid arthritis were treated with oral methotrexate (MTX) for more than 10 years. MTX was given as a bolus of 5-15 mg/week; the total cumulative dose ranged from 4,690 mg to 10,230 mg. Liver biopsies were performed on 21 of the patients to assess possible fibrosis and cirrhosis. Grade I histopathologic changes were found in 13 of the 21 biopsy samples, grade II changes were found in 3, and grade IIIA changes (mild fibrosis) were found in 5 specimens. None of the biopsy samples showed cirrhosis. Repeat biopsies were performed on the 5 patients with grade IIIA changes while they were still taking MTX. No progression of the fibrosis was noted. Two of the 5 samples, however, were graded IIIB because of portal and perilobular inflammation. Our findings support the premise that prolonged administration of oral MTX, when given as a weekly bolus at a low dose, does not cause cirrhosis or severe fibrosis in the rheumatoid arthritis patient who does not abuse alcohol.