Iron stores in alcohol abusers. I. Liver iron

Iron as a therapeutic target in chronic liver disease

It was clearly realized more than 50 years ago that iron deposition in the liver may be a critical factor in the development and progression of liver disease. The recent clarification of ferroptosis as a specific form of regulated hepatocyte death different from apoptosis and the description of ferritinophagy as a specific variation of autophagy prompted detailed investigations on the association of iron and the liver. In this review, we will present a brief discussion of iron absorption and handling by the liver with emphasis on the role of liver macrophages and the significance of the iron regulators hepcidin, transferrin, and ferritin in iron homeostasis. The regulation of ferroptosis by endogenous and exogenous mod-ulators will be examined. Furthermore, the involvement of iron and ferroptosis in various liver diseases including alcoholic and non-alcoholic liver disease, chronic hepatitis B and C, liver fibrosis, and hepatocellular carcinoma (HCC) will be analyzed. Finally, experimental and clinical results following interventions to reduce iron deposition and the promising manipulation of ferroptosis will be presented. Most liver diseases will be benefited by ferroptosis inhibition using exogenous inhibitors with the notable exception of HCC, where induction of ferroptosis is the desired effect. Current evidence mostly stems from in vitro and in vivo experimental studies and the need for well-designed future clinical trials is warranted.

Decreased hepatic iron in response to alcohol may contribute to alcohol-induced suppression of hepcidin

Hepatic Fe overload has often been reported in patients with advanced alcoholic liver disease. However, it is not known clearly whether it is the effect of alcohol that is responsible for such overload. To address this lacuna, a time-course study was carried out in mice in order to determine the effect of alcohol on Fe homoeostasis. Male Swiss albino mice were pair-fed Lieber-DeCarli alcohol diet (20 % of total energy provided as alcohol) for 2, 4, 8 or 12 weeks. Expression levels of duodenal and hepatic Fe-related proteins were determined by quantitative PCR and Western blotting, as were Fe levels and parameters of oxidative stress in the liver. Alcohol induced cytochrome P4502E1 and oxidative stress in the liver. Hepatic Fe levels and ferritin protein expression dropped to significantly lower levels after 12 weeks of alcohol feeding, with no significant effects at earlier time points. This was associated, at 12 weeks, with significantly decreased liver hepcidin expression and serum hepcidin levels. Protein expressions of duodenal ferroportin (at 8 and 12 weeks) and divalent metal transporter 1 (at 8 weeks) were increased. Serum Fe levels rose progressively to significantly higher levels at 12 weeks. Histopathological examination of the liver showed mild steatosis, but no stainable Fe in mice fed alcohol for up to 12 weeks. In summary, alcohol ingestion by mice in this study affected several Fe-related parameters, but produced no hepatic Fe accumulation. On the contrary, alcohol-induced decreases in hepatic Fe levels were seen and may contribute to alcohol-induced suppression of hepcidin.

Mitoneet mediates TNFα-induced necroptosis promoted by exposure to fructose and ethanol

Fructose and ethanol are metabolized principally in the liver and are both known to contribute to the development of hepatic steatosis that can progress to hepatic steatohepatitis. The present study indentifies a synergistic interaction between fructose and ethanol in promoting hepatocyte sensitivity to TNFα-induced necroptosis. Concurrent exposure to fructose and ethanol induces the overexpression of the CDGSH iron-sulfur domain-containing protein 1 (CISD1 or mitoneet), which is localized to the outer mitochondrial membrane. The increased expression of mitoneet primes the hepatocyte for TNFα-induced cytotoxicity. Treatment with TNFα induces the translocation of a Stat3-Grim-19 complex to the mitochondria, which binds to mitoneet and promotes the rapid release of its 2Fe-2S cluster, causing an accumulation of mitochondrial iron. The dramatic increase of mitochondrial iron provokes a surge in formation of reactive oxygen species, resulting in mitochondrial injury and cell death. Additionally, mitoneet is constitutively expressed at high levels in L929 fibrosarcoma cells and is required for L929 cells to undergo TNFα-induced necroptosis in the presence of caspase inhibition, indicating the importance of mitoneet to the necroptotic form of cell death.

Iron homeostasis in the liver

Iron is an essential nutrient that is tightly regulated. A principal function of the liver is the regulation of iron homeostasis. The liver senses changes in systemic iron requirements and can regulate iron concentrations in a robust and rapid manner. The last 10 years have led to the discovery of several regulatory mechanisms in the liver that control the production of iron regulatory genes, storage capacity, and iron mobilization. Dysregulation of these functions leads to an imbalance of iron, which is the primary cause of iron-related disorders. Anemia and iron overload are two of the most prevalent disorders worldwide and affect over a billion people. Several mutations in liver-derived genes have been identified, demonstrating the central role of the liver in iron homeostasis. During conditions of excess iron, the liver increases iron storage and protects other tissues, namely, the heart and pancreas from iron-induced cellular damage. However, a chronic increase in liver iron stores results in excess reactive oxygen species production and liver injury. Excess liver iron is one of the major mechanisms leading to increased steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma.

Liver affection in iron overload studied with serum ferritin and serum aminotransferases

Liver dysfunction as measured by S-ALAT activity was present in 72% of patients over 40 years of age with HLA-related iron overload, mainly detected by laboratory screening. Liver dysfunction was correlated to the amount of iron stored (r = 0.54, p less than 0.001). When iron was removed by phlebotomy, liver function returned to normal. S-ALAT activity was closely correlated to serum ferritin concentration (r = 0.73, p less than 0.001). Even a mild iron excess can affect hepatocytes and result in increased levels of ferritin and aminotransferases in serum. Patients with "transaminitis" should be investigated for iron overload.

Prevalence of iron overload in central Sweden

An increase in the iron content of food may be harmful to people with genetic hemochromatosis. We studied the prevalence of this disorder in Sweden, which is the country with the world's highest iron fortification of food. Serum ferritin and transferrin (TIBC) saturation levels were used as initial screening methods. Three (0.5%) of 623 males aged 30-39 years were found to have genetic hemochromatosis. Family studies revealed 10 additional homozygotic family members. A prevalence of 0.5% of homozygotes (q2) implies a gene frequency (q) of 6.9% or a heterozygote frequency (2 x Q) of 13.8%. The high gene frequency may be explained by a possible genetic advantage of heterozygotes in the past. We conclude that idiopathic hemochromatosis is not as rare as previously thought. Affected persons should be detected and treated before irreversible organ damage occurs. This study demonstrates that serum ferritin levels together with TIBC saturation levels are adequate methods for screening populations.

Regional differences in the idiopathic hemochromatosis gene frequency in Sweden

Screening for idiopathic hemochromatosis (IH) in 941 men, 55 years of age, did not reveal any individual with both biochemical abnormalities and liver iron content compatible with homozygosity for the IH gene. In a large autopsy series of 8 834 males representative of southern Sweden, we found classical hemochromatosis in 0.1%. The results are in contrast with the high frequency of homozygous IH found in the county of Jämtland in central Sweden. We suggest that the difference in gene frequency is a result of enrichment of the recessive IH gene in the Jämtland population by the mechanisms of sampling and drift. We conclude that population screening for early IH in southern Sweden is not worthwhile.

Screening for iron overload using transferrin saturation

People with parenchymal iron overload exhibit an elevated serum iron concentration and a raised transferrin (TIBC) saturation early in the course of the disease. They can therefore be detected by simple laboratory tests before organ damage has occurred. In this study running for 2 months, 10512 samples from approximately 8750 patients and blood donors were examined in a county hospital in Central Sweden. Abnormal TIBC saturation (greater than 70%) was found in 1.7% of the samples. This abnormality was caused by physiological fluctuations in serum iron in 44%, liver disease in 22%, blood disorder in 10%, iron therapy in 10.5% and parenchymal iron overload in 11.5%. The diagnosis of iron overload was confirmed by measuring the serum ferritin concentration and by performing the desferrioxamine test, liver biopsy, quantitative phlebotomy and family studies including HLA typing. We found a prevalence of iron overload of 0.24%. This figure is almost certainly too low because some affected patients were probably lost because of TIBC desaturation induced by inflammatory conditions.

Hepcidin is down-regulated in alcoholic liver injury: implications for the pathogenesis of alcoholic liver disease

BACKGROUND

Alcoholic liver disease is known to be associated with abnormal iron homeostasis, and iron metabolism itself is regulated by the liver-derived peptide hepcidin. Both CCAAT enhancer binding protein alpha (C/EBPalpha) and interleukin 6 (IL-6) have been shown to regulate hepcidin gene transcription.

AIM

To investigate mechanisms underlying alcohol-induced disturbances in iron homeostasis by measuring the expression of hepcidin and C/EBPalpha mRNA using in vivo and in vitro models of alcoholic liver injury.

METHODS

Male rats were pair-fed an alcoholic liquid diet for 12 weeks. RT-PCR was performed on liver tissue using specific primers for hepcidin and C/EBPalpha. The effect of alcohol on hepcidin and C/EBPalpha gene expression was also determined in isolated hepatocytes, HuH-7 cells and HepG2 cells treated with 50 mM ethanol, 200 microM acetaldehyde, and/or 20 ng/ml IL-6.

RESULTS

Hepcidin and C/EBPalpha mRNA expression were significantly decreased in alcohol-fed rats compared with pair-fed controls (6-fold p < 0.001 and 2.2-fold p < 0.0002 reduction, respectively) and hepatic lipid peroxidation was increased by 32.5% (p < 0.05) in alcohol-fed rats compared with controls. Hepcidin gene expression was not altered significantly in cells cultured in the presence of 50 mM ethanol. Following 24 hour stimulation by IL-6, there was a 4-fold increase in hepcidin expression in hepatocytes and a 9-fold increase in HuH-7 cells. Ethanol (50 mM) attenuated the IL-6-induced increase in hepcidin expression in HuH-7 cells (9-fold to a 4-fold increase) but not in hepatocytes. Acetaldehyde had no effect on hepcidin gene expression in cells in culture.

CONCLUSION

The down-regulation of hepcidin and C/EBPalpha gene expression shown in vivo implies disturbed iron sensing contributing to the hepatosiderosis seen in alcoholic liver disease, possibly by mechanisms involving the IL-6 signaling cascade.

Zinc, copper, manganese, and iron in chronic alcoholic liver disease

Ethanol consumption and/or liver damage may alter liver content of several trace elements, as iron, zinc, copper, and manganese. This alteration may play a role on ongoing liver fibrogenesis. Based on these facts we have determined liver, serum, and urinary Mn, Cu, Zn, and Fe levels in a group of alcoholic cirrhotics and noncirrhotics with normal renal function, comparing them with those of controls. We have observed low liver zinc and high liver copper--this last in relation with histomorphometrically determined total amount of liver fibrosis--and manganese contents in cirrhotics, together with increased excretion of zinc and iron and decreased excretion of manganese. Zinc, iron, and copper excretion kept a relation with data of severity of cirrhosis, including mortality in the case of urinary copper, independently of the use of diuretics. Thus, liver copper and urinary iron, zinc, and copper excretion seem to be related with data of severity of chronic alcoholic liver disease. Low urinary manganese excretion may play a role on liver manganese overload.

Maternal risk factors in fetal alcohol syndrome: provocative and permissive influences

We present an hypothesis integrating epidemiological, clinical case, and basic biomedical research to explain why only relatively few women who drink alcohol during pregnancy give birth to children with alcohol-related birth defects (ARBDs), in particular, Fetal Alcohol Syndrome (FAS). We argue that specific sociobehavioral risk factors, e.g., low socioeconomic status, are permissive for FAS in that they provide the context for increased vulnerability. We illustrate how these permissive factors are related to biological factors, e.g., decreased antioxidant status, which in conjunction with alcohol, provoke FAS/ARBDs in vulnerable fetuses. We propose an integrative heuristic model hypothesizing that these permissive and provocative factors increase the likelihood of FAS/ARBDs because they potentiate two related mechanisms of alcohol-induced teratogenesis, specifically, maternal/fetal hypoxia and free radical formation.

A long-term study of the interaction between iron and alcohol in an animal model of iron overload

BACKGROUND/AIMS

The hypothesis that chronic alcohol ingestion potentiates iron-associated liver injury was investigated in the 'carbonyl iron-overload rat model'.

METHODS

Newborn male and female Wistar-Furth rats (seven per group) were used to investigate iron-alcohol interaction over a 26-week period. Groups 1 and 2 were iron loaded from birth, while the others received normal diet. At 10 weeks all rats commenced Lieber-DeCarli liquid diet; additional treatments were: group 1 6 g carbonyl iron/1000 ml diet plus alcohol; group 2 carbonyl iron in the liquid diet; group 3 alcohol in the liquid diet; group 4, the controls, received liquid diet only.

RESULTS

This study confirmed our previous observation that iron-loading from birth resulted in grade III-IV siderosis, in both male and female rats, and caused fibrosis associated with periportal macrophages. Alcohol-feeding, in addition to iron-feeding for 26 weeks significantly lowered the hepatic iron concentration in both male and female rats compared to those fed iron only (p < 0.05). Alcohol feeding did increase hepatic fibrosis in the iron-loaded animals. However, serum alanine aminotransferase activity was significantly higher in the iron-alcohol group than in the other groups (p < 0.05).

CONCLUSIONS

Thus, contrary to expectation, chronic alcohol feeding failed to potentiate hepatic fibrosis in iron-overloaded rats, although there was rather more hepatocyte necrosis, and the serum alanine aminotransferase activity was significantly higher in the iron-alcohol group than in the other groups.

Effects of alcohol, carbon tetrachloride, and choline deficiency on iron metabolism in the rat

The effects of alcohol on hepatic iron uptake and intestinal iron transport were studied in rats fed a nutritionally replete liquid diet containing varying quantities of ethanol. Results were compared with those from animals exposed to carbon tetrachloride (CCl4) to produce hepatocellular necrosis or a choline-deficient diet to produce steatosis and cirrhosis. A high ethanol intake for 4 or 10 weeks produced hepatic steatosis. CCl4 produced hepatocellular necrosis. Choline deficiency was associated with steatosis +/- cirrhosis. Intestinal iron transport was unaffected by ethanol, CCl4, or choline deficiency. Hepatic iron uptake was significantly depressed in rats consuming 11.7 g/kg/day ethanol (p < 0.01) for 4 weeks. Choline-deficient animals studied at 14 weeks also had significantly decreased hepatic iron uptake (p < 0.01); results were similar in the cirrhotic and noncirrhotic animals. Conversely, CCl4 exposure produced a significant 5-fold increase in hepatic iron uptake (p < 0.001). Results suggest that ethanol consumption, fatty liver, and cirrhosis are not responsible for any increase in iron absorption or of hepatic iron uptake in the rat model. Acute hepatocellular injury is followed by increased hepatic iron uptake.

Iron uptake from transferrin and asialotransferrin by hepatocytes from chronically alcohol-fed rats

Chronic alcohol intake is often associated with alterations to iron homeostasis and an increase in the serum levels of carbohydrate-deficient transferrin. As the liver is a major iron storage site and also synthesizes transferrin, the normal serum iron transport protein, the aim of this study was to test the hypothesis that these disturbances in iron homeostasis were caused by altered hepatocyte iron uptake from the abnormal transferrin. To achieve this, we have investigated iron uptake from both transferrin and asialotransferrin by hepatocytes from male Sprague-Dawley rats fed the De Carli and Lieber alcohol diet. Iron uptake from transferrin by hepatocytes from alcoholic rats was less than 60% that of control values, and in the presence of 50 mM ethanol decreased still further to 35% of the uptake by the corresponding control cells. Iron uptake from rat asialotransferrin was reduced in both groups when compared to that observed from normal transferrin; 13% by control cells and 39% by hepatocytes from alcohol-fed rats. Alcohol, however, had no further effect on asialotransferrin uptake by either hepatocytes from alcohol-fed rats, or their pair-fed controls. Transferrin binding to hepatocytes was also influenced by the alcohol diet. Although there was no difference in binding at 37 degrees C, cells from alcohol-fed rats bound 85% of this total at 4 degrees C, compared to 44% by control hepatocytes. Similar values were also obtained for hepatocyte binding of asialotransferrin; alcohol feeding resulted in an increase in binding at 4 degrees C to 73% from 58% with control cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Coincidental hemochromatosis and viral hepatitis

A 35-year-old woman presented with liver failure, hepatic iron overload, and secondary amenorrhea due to hypogonadotropic hypogonadism. She had chronic inflammatory hepatitis which was considered to be due to post-transfusional viral hepatitis. Her hepatic iron overload was considered to be due to hemochromatosis. Her premature menopause was thought to be due to the severity of her liver disease, but her iron overload also could have contributed to gonadotrophin deficiency. She underwent liver transplantation and 5 months later, she experienced return of menstrual function. The distinction between hepatitis as a cause of iron loading, hemochromatosis as a cause of hepatic inflammation, the small influence of alcohol on increased iron stores, and other features of her history, physical examination, and laboratory evaluation are discussed.

Iron mediates production of a neutrophil chemoattractant by rat hepatocytes metabolizing ethanol

Ethanol metabolism in hepatocytes is accompanied by release of a potent lipid chemoattractant for neutrophils. Production of the factor may initiate the inflammation associated with alcoholic hepatitis. In previous studies with a cytosol system from liver, production was blocked by iron chelators as well as by catalase and superoxide dismutase, suggesting the involvement of oxyradicals in formation of the chemoattractant. These studies have examined the role of iron in intact hepatocytes using cells from rats fed an iron-deficient diet, a control diet or a diet containing 3% carbonyl iron. The iron content averaged 1.4 nmol/mg protein in iron-deficient cells, 6.3 in controls and 135.3 in iron-loaded cells. Hepatocytes from all groups were established in primary culture and incubated with ethanol (10 mM); the medium was assayed for chemoattractant activity for human neutrophils. Cultures from chow-fed or iron-loaded animals produced chemoattractant as previously reported. By contrast, chemoattractant production was undetectable in the iron-deficient cultures. Addition of ferric citrate (10 microM) restored chemoattractant production while increasing cellular iron in the deficient cells less than 50% (to 2.3 nmol/mg protein). Addition of desferrioxamine mesylate to cultures of iron-loaded cells ablated chemoattractant production. The data provide evidence for the importance of hepatocellular iron in production of this alcohol-related lipid chemoattractant and suggest that a small intracellular pool of "free" iron plays a critical role.

Decreased serum selenium and magnesium levels in drunkenness arrestees

Serum levels of selenium magnesium, copper, zinc and iron were studied in chronic drunkenness arrestees and a healthy control group. The mean serum concentrations of selenium and magnesium were both significantly lower (P less than 0.01) in drunkenness arrestees than in the control subjects. The mean alcohol intake was 190 g of absolute alcohol daily in drunkenness arrestees and 14 g in controls. The erythrocyte glutathione peroxidase concentrations of the study groups did not support poor selenium intake as a principal cause of low selenium concentration in the serum.

Determination of iron in cardiac and liver tissues by plasma emission spectroscopy

A simple plasma emission spectroscopic method for the determination of iron in liver and cardiac tissue is described. Using this technique, iron was extracted quantitatively from liver tissue of mass 14.2 to 65.4 mg wet weight, and heart tissue of mass 5.9 to 27.4 mg wet weight. Iron added to liver as aqueous ferric nitrate was recovered in the range 93 to 108%. Reference ranges for liver and myocardial iron on post mortem tissue gave respectively mean values of 0.841 mg/g dry weight (Range 0.310 to 1.600, n = 37) and 0.340 mg/g dry weight (Range 0.290 to 0.470, n = 8). Data on patients with haemochromatosis and transfusion siderosis are also presented.

Depression of iron uptake from transferrin by isolated hepatocytes in the presence of ethanol is a pH-dependent consequence of ethanol metabolism

Incubation of freshly isolated rat hepatocytes with highly purified radiolabeled rat transferrin in weakly buffered medium in the presence of 10 mM ethanol resulted in a marked diminution of iron uptake by these cells, associated with a greater pH depression than in ethanol-free control studies. This effect on iron uptake persisted, even when the cells were preincubated for 90 min with ethanol before the addition of transferrin. Increasing the buffering capacity of the system or the addition of a metabolic inhibitor of alcohol dehydrogenase (4-methylpyrazole) returned iron uptake to control values. Acetaldehyde, acetate, lactate (products of ethanol metabolism), and 3-butanol (an alcohol not metabolized by alcohol dehydrogenase) had no influence on iron uptake. Further investigation of iron uptake over the pH range 6-8.5 revealed a marked dependency of iron uptake on the extracellular pH. Leucine incorporation into cell protein was also found to be pH dependent. It is suggested that, in the light of current understanding of transferrin recycling by other cell types, the disturbances of iron homeostasis observed in alcoholics can be partially accounted for by alterations in their acid-base metabolism.

Trace elements in normal and cirrhotic human liver tissue. I. Iron, copper, zinc, selenium, manganese, titanium and lead measured by X-ray fluorescence spectrometry

Trace elements (Fe, Cu, Zn, Se, Mn, Ti, Pb) were measured by X-ray fluorescence spectrometry in normal liver tissue obtained at autopsy from 74 subjects (44 male, 30 female), median age 62 years (range 20-87), and in tissue from 27 cirrhotic livers (14 alcoholic, 13 non-alcoholic cirrhosis). The element content (median and 5-95 percentile interval) in normal livers in mmol/kg dry tissue was: Fe, 16.51 (7.82-39.03); Cu, 0.378 (0.189-0.629); Zn, 4.01 (2.59-9.33); Se, 0.018 (less than 0.004-0.035); Mn, less than 0.055 (less than 0.055-0.237); Ti, less than 0.146 (less than 0.146-0.919); Pb, less than 0.0005 (less than 0.0005-0.0154). Only copper content showed a sex difference, being higher in males than in females (P less than 0.04). In both groups of cirrhotic liver, Fe content was within normal, Cu content above normal (P less than 0.05, P less than 0.02), and Se content below normal (P less than 0.0001, P less than 0.04). Alcoholic cirrhotic livers had lower Zn levels (P less than 0.02), higher Mn levels (P less than 0.06), and higher Pb levels (P less than 0.03) than normal livers.

Porphyria cutanea tarda, or the uroporphyrinogen decarboxylase deficiency diseases

The term "porphyria cutanea tarda" originally described the dermatological manifestations of various chronic porphyrias. Its usage now is usually restricted to disorders associated with a deficiency of uroporphyrinogen decarboxylase (UROD), for which the term "UROD-deficiency" may be more appropriate. Four etiologic agents have been implicated in this condition: alcohol, oral estrogens, halogenated aromatic hydrocarbons, and iron. An inherited deficiency of UROD is also recognized, with increased susceptibility to these agents. Certain halogenated aromatic hydrocarbons can cause UROD-deficiency in animals and synergism with iron is demonstrable in this model. Neither ethanol nor estrogen has been shown to cause UROD-deficiency in animals. Treatment by venesection to reduce total body iron is safe and effective. The 4-aminoquinoline antimalarial drugs also provide effective treatment, possibly by lysis of affected liver cells. Unlike venesection, they may not reverse the biochemical lesion which causes porphyrins to accumulate. The mechanism of acquired UROD-deficiency is not clear but animal studies suggest a role for the hepatic mixed function oxygenases which initiate iron-dependent inactivation of UROD. Diagnosis is simple, often requiring only appropriate clinical data and testing of a random urine sample. Although not common, the disorder is the most frequently diagnosed disturbance of porphyrin metabolism in many countries, and further insight into its unusual pathogenesis may clarify the hepatotoxic effects of the 4 etiologic agents.

Iron absorption from red and white wines

Iron (3 mg) was added as ferrous sulphate to 2 dl red wine, white wine and 7% alcohol and its absorption was then measured in 38 fasting male subjects. (The original concentrations of iron in the two wines were low, being 1.01-1.08 mg/l (red wine) and 0.13-0.20 (white wine]. The geometric mean absorption from red wine was only 20% of that from the alcohol solution whilst more than 4 times as much was absorbed from white wine as from the alcohol. Direct comparison showed greater absorption from white wine (10.4%) than from red wine (4.4%). Removal of about 80% of the polyphenols in red wine increased the geometric mean iron absorption from 1.9% to 3.6%. In vitro experiments indicated that iron was less soluble and less dialysable in red wines than in white wines. This was possibly due to the binding of iron to polyphenols in red wines. Electrophoretic studies suggested that the iron in white wines was complexed to hydroxycarboxylic acids.

HLA as a marker of the hemochromatosis gene in Sweden

The frequency of HLA-A3 and HLA-B14 antigens was found to be significantly (P = less than 0.0001) higher in a series of 50 unrelated and unselected Swedish patients with idiopathic hemochromatosis (IH) than in controls, being 66% and 32% for A3 and 22% and 2% for B14. The haplotype A3B14 was associated with the highest risk in this material (relative risk 23.4). One family with this haplotype was traced back to the end of the seventeenth century. The pattern of HLA antigens associated with IH in Sweden shows remarkable similarity to those reported from England and Brittany.

Transferrin glycans: a possible link between alcoholism and hepatic siderosis

The hepatic uptake of 59Fe from diferric rat and rabbit asialotransferrins and from human transferrin lacking two sialyl residues was investigated in rats in experiments lasting for 1 hr. The 59Fe attached to either of these preparations disappeared from the plasma more rapidly than the 59Fe introduced with the unmodified respective parent proteins. Most of the 59Fe activity that had disappeared from the circulation could be recovered with the liver. Studies with double-labeled (125I, 59Fe) preparations showed that the enhanced 59Fe clearance was not associated with increased catabolism of the modified transferrins. Prolonged, heavy alcohol consumption, as shown by others, results in the appearance of sialic acid-deficient transferrin (two residues missing) in human serum. We suggest that the increased capacity of transferrin deficient in sialic acid to selectively deposit iron in the hepatocyte may be of significance for the development of the hepatic siderosis observed in alcoholism.

Iron and haemochromatosis

There have recently been considerable advances in the understanding of the inheritance of idiopathic haemochromatosis (McKusick 23520). The disorder is determined by a locus closely linked to the HLA loci on the short arm of chromosome 6. There is a recessive mode of transmission. The gene frequency may be as high as 0.05 in some parts of the world. HLA typing makes it possible to identify family members who are homozygous for idiopathic haemochromatosis and measurement of transferrin saturation and serum ferritin concentration will identify those with iron overload. Treatment is by regular phlebotomy. Few advances have been made in the 50 years in the understanding of the abnormality which permits the increased absorption of iron and which causes the iron overload.

Effects of iron-loading and ethanol treatment on rat porphyrin metabolism

Rats were fed for 50 weeks with a standard diet containing 5.9% ferric ammonium sulphate. Half of these animals drank normal water, and the other half water containing 5% ethanol (groups 1 and 2). Two other groups received normal food, but drank water containing 5 or 10% ethanol (groups 3 and 4) for 40 weeks. Histologic examinations revealed that the iron-loading resulted in only mild hepatic siderosis in groups 1 and 2, the degree of siderosis not differing appreciably in the two groups. The ethanol led to fatty degeneration too in the liver of animals in group 2. Both iron-loading and ethanol treatment, either separately or in combination, increased the porphyrin excretion, but the distribution of the various porphyrins in the urine and faeces showed merely the symptoms of an aspecific poisoning. A significantly elevated uroporphyrin excretion was not observed in any of the groups, and thus the results support the view that dietary iron-loading and ethanol consumption can not be regarded as direct aetiologic factors in the pathomechanism of porphyria cutanea tarda. At the same time, the results suggest that vitamin E therapy, frequently employed effectively in porphyria cutanea tarda, can not be considered a causal intervention as regards the mechanism of action.

Hepatic siderosis in alcoholics

In a population of 157 (120 males, 37 females) predominantly British alcoholics with liver disease, the incidence of some degree of hepatic siderosis, as estimated by stainable parenchymal iron, was 57.3%. The incidence of significant siderosis (grades III and IV) was 7%, and was similar for both sexes. In the female alcoholics there was a significant correlation between age and the degree of siderosis (P less than 0.05)--four of the five females with significant siderosis being premenopausal. In the male alcoholics there was a significant inverse relationship between the grams of ethanol consumed per day and the degree of siderosis (P less than 0.05) and a significant correlation between the percentage saturation of iron-binding protein and the degree of siderosis (P less than 0.05). The mean daily iron intake from alcoholic beverages was 1.5 mg; there was no relationship between the amount of iron ingested in the alcohol and the degree of siderosis. In this population of alcoholics the incidence of significant siderosis in both sexes was low.

Effect of a single ingestion of alcohol on iron absorption

The effect of alcohol on inorganic and organic iron absorption was studied in 70 subjects, using a whole-body counter technique. The mean iron absorption of a test dose was 24.44%, while in the presence of whisky, absorption fell to 9.73% (P less than 0.0001). Absorption of a test dose in the presence of whisky without alcohol was 10.14% (P less than 0.0001). The alcohol in whisky, therefore, was not responsible for the diminished iron absorption (P greater than 0.20). The absorption of the iron contained in wine with alcohol was 73.31 microgram and wine without alcohol was 67.50 microgram. The difference was not statistically significant (P greater than 0.20). The absorption of inorganic iron contained in a test meal was 165.55 microgram and was not changed in the presence of ethanol (151.35 microgram) (P greater than 0.10). However, the presence of ethanol affected the absorption of heme iron: 538.68 microgram compared with 442.41 microgram with ethanol (P less than 0.0001). These studies show that the acute ingestion of ethanol does not influence the absorption of inorganic iron, while it does diminish the absorption of the organic form.

Liver morphology in acute viral hepatitis related to the hepatitis B antigen

The liver histology in infectious hepatitis or hepatitis A (HA) and serum hepatitis or hepatitis B (HB) is generally described as identical. However, the clinical separation of the two types has been a problem. Today a serological reaction based on the well documented association between hepatitis antigen and HB is of great assistance in the differential diagnosis. The present study of 165 hepatitis cases separated into hepatitis A and B by this test method indicates quantitative differences in the liver histology of the two types. Thus HB was associated with more prominent parenchymal cell damage and Kupffer cell reaction, while intrahepatic cholestasis was found in a significantly higher frequency in cases presumed to represent HA. The presence of intrahepatic cholestasis was associated with higher levels of serum bilirubin but otherwise no correlation was found between liver morphology and biochemical liver tests. The patients included a group of young intravenous amphetamine addicts with HB. No differences of importance were found histologically in addicts and other patients with hepatitis B.