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PubMed1989

Myocardial iron grading by endomyocardial biopsy. A clinico-pathologic study on iron overloaded patients.

Endomyocardial biopsy was performed in 13 patients with primary or secondary iron overload. Prussian blue staining showed visible iron in the biopsy fragments of 8 out of 13 patients. Because of the inhomogeneity of iron deposition in the biopsy fragments, a semi-quantitative myocardial iron grading system was used in which the percentage of Perls' positive cells on 4 to 6 biopsy fragments was averaged from each case. The presence of stainable iron in the myofibrils was not predictable from serum iron, transferrin saturation, serum ferritin or liver iron grading, nor from evidence of endocrine dysfunction. In patients with Perls' positive material in the myocardium, there was a significant correlation between the endomyocardial iron grade and serum iron and transferrin saturation. These results suggest that other factors besides the body iron load determine cardiac iron deposition. The fact that myocardial siderosis was documented only in patients with hepatic cirrhosis, irrespective of the hepatic iron load, suggests that severe liver damage may be a prerequisite for the accumulation of iron in the heart.

Adult↗

PubMed1998

African iron overload and hepatocellular carcinoma (HA-7-0-080).

Although HLA-linked hemochromatosis greatly increases the risk for hepatocellular carcinoma in people of European ancestry, iron overload in Africa is not thought to be etiologically related to this malignancy. To determine if African iron overload may be associated with hepatocellular carcinoma, we reviewed 320 consecutive diagnostic liver biopsies processed at the University of Zimbabwe from 1992 to 1994 and we selected for analysis 215 biopsies from adults that were suitable for the histological assessment of hepatocellular iron. Subjects were stratified according to hepatocellular iron grades of 0-2+ (normal levels to mild siderosis; n = 183) and grades of 3+ and 4+ (distinctly elevated levels consistent with iron overload; n = 32). Thirty-six subjects had hepatocellular carcinoma. Logistic regression modeling revealed a significant association between iron overload and hepatocellular carcinoma after adjustment for age, sex and and the presence of portal fibrosis or cirrhosis (p = 0.041). The odds of hepatocellular carcinoma in subjects with iron overload was 3.1 (95% confidence interval of 1.05-9.4) times that of subjects without iron overload. While we could not test for exposure to viral hepatitis or to aflatoxins in this study, our findings suggest that iron overload may be a risk factor for hepatocellular carcinoma in Africa.

Adult↗

PubMed1992

Hepatocellular carcinoma in porphyria cutanea tarda: frequency and factors related to its occurrence.

Thirty-eight patients with porphyria cutanea tarda (PCT) have been seen in the last 18 years. Five of these patients (13%) developed hepatocellular carcinoma (HCC) during follow-up. We analyzed the differences in clinical, laboratory and liver histology findings at presentation, between patients who developed HCC during follow-up (HCC-group, n = 5) and those who did not (PCT-group, n = 33). Of the clinical features the duration of skin-symptoms was longer in the HCC-group (mean: 10.4 +/- 1.1 years) than in the PCT-group (mean: 1.4 +/- 1 years) (p less than 0.001). No differences in routine laboratory findings were found. Although 11/38 (29%) patients had serologic evidence of a past hepatitis B virus infection and 7/38 (18%) patients had antibodies against hepatitis C virus, no differences in these parameters were found between the PCT-group and the HCC-group. In all 34 liver biopsies a variable degree of siderosis was found (PCT-group vs. HCC-group: NS). Only piecemeal necrosis (p less than 0.01) and advanced fibrosis or cirrhosis (p less than 0.001) were more common in liver biopsies in the HCC-group. In conclusion, factors related to an increased risk of HCC in PCT are: a) a long symptomatic period before start of treatment and b) the presence of chronic active hepatitis and/or advanced fibrosis or cirrhosis in liver biopsies.

Adult↗

PubMed1979

Intramuscular iron therapy and tapetoretinal degeneration. A case report.

A 63-years-old male with pernicious anemia had been treated for 20 years with weekly injections of iron-dextran and cyanocobalamine. Ophthalmological examination revealed the ophthalmoscopic picture of a tapetoretinal degeneration, reduced visual acuity and narrow visual fields. ERG and dark-adaptation test were normal. Hematological examination including liver and bone marrow biopsies gave no support for the existence of systemic siderosis. It is proposed that the retinal degeneration is due to the extensive parenteral iron treatment with a total dose of approximately 100 grams of iron. This theory is supported by a previous experimental report.

Aged↗

PubMed2003

Disproportionately elevated fasting proinsulin levels in normoglycemic patients with thalassemia major are correlated to the degree of iron overload.

OBJECTIVE: To analyze the secretion of the insulin precursor proinsulin in patients with beta-thalassemia and its possible relation to iron overload. METHODS: We assessed fasting proinsulin, insulin, C-peptide and glucose levels from 34 patients with beta-thalassemia and 33 healthy controls. The correlation to age, body mass index, hepatic iron concentration, serum ferritin and serum AST was analyzed. RESULTS: Fasting proinsulin (p < 0.002) and proinsulin-to-insulin ratio (p < 0.02) were significantly increased in patients with thalassemia irrespective of the degree of glucose tolerance. They correlated positively to serum ferritin, liver iron, patient age and serum AST (all p < 0.05). CONCLUSIONS: Disproportionately elevated proinsulin levels in thalassemic patients indicate early beta-cell dysfunction due to siderosis. An additional biological significance of hyperproinsulinemia and its possible ability to predict long-term iron toxicity in these patients remain to be clarified.

Adolescent↗

PubMed1992

Iron overload of the liver by trimethylhexanoylferrocene in rats.

Iron-deficient female Wistar rats were fed a diet, which contained 0.5% trimethylhexanoylferrocene, over a 56-week period. This dietary iron loading resulted in a progressive siderosis and enlargement of the liver with a maximum iron content of 947.0 +/- 148.0 mg (vs. 0.07 +/- 0.04 mg in iron deficiency) and a maximum organ weight of 39.4 +/- 6.6 g (vs. 6.9 +/- 1.4 g in iron-deficient control rats). Up to 43 weeks, whole liver iron rose by increase in iron concentration (max. 28.0 +/- 6.1 mg/g wet weight, w.w.) as well as by enlargement of the organ. Afterwards whole liver iron increased solely by ongoing hepatomegaly. At the commencement of iron loading, stainable iron was almost exclusively stored by hepatocytes equally throughout all areas of the liver lobule. Later, the distribution of iron-loaded hepatocytes became strikingly periportal, and, in addition, Kupffer cells as well as sinus-lining endothelia began to store iron. Animals with a liver iron concentration of more than 10.4 +/- 0.75 mg/g w.w. showed no further increase in ferritin and haemosiderin within hepatocytes. Iron-burdened Kupffer cells/macrophages, however, accumulated permanently, hereby forming intrasinusoidal and portal siderotic nodules and areas. First signs of liver damage such as necrosis of single hepatocytes and mild fibrosis began at a liver iron concentration of 14.7 +/- 1.4 mg/g w.w. With advancement of iron loading, focal necrosis of hepatocytes and iron-burdened macrophages took place, and significant perisinusoidal as well as portal fibrosis developed. Cirrhosis, however, the final stage of impairment in iron overload of the liver in humans, could not be induced in this animal model up to now.

Animals↗

PubMed1994

Pattern of iron storage in the rat heart following iron overloading with trimethylhexanoyl-ferrocene.

Female Wistar rats with slight iron deficiency anemia were kept on a diet containing 0.5% trimethylhexanoyl (TMH)-ferrocene for up to 79 weeks. In the state of iron deficiency, the heart was free of light-microscopically detectable iron. After 7 weeks of the TMH-ferrocene diet, the first iron-positive granules appeared in perivascular macrophages. Further oral administration caused a progression of iron deposition in these cells, visible in the form of a granular staining but also as a diffuse iron staining of the cytoplasm. Accordingly, at the electron-microscopical level, the iron was stored partly as free ferritin molecules in the cytosol, and partly in lysosomes in the form of ferritin and/or hemosiderin. After 11 weeks, further iron-positive cells with relatively small dark-blue granules were found in the vicinity of capillaries, which could be identified as fibrocytes by means of electron microscopy. In addition, slight iron deposition occurred in the endothelial cells of the cardiac capillaries, likewise mainly in the form of small, uniform siderosomes. The myocytes showed no product of Perls' Prussian blue reaction during the whole period of investigation. From the 11th week onwards, discrete ferritin molecules were detected electron microscopically within lysosomes of these cells. Their amount increased slowly with progression of the TMH-ferrocene feeding period. Free ferritin molecules could be observed in the cytosol of fibrocytes, endothelial cells and myocytes in only very slight concentrations, whilst they were more plentiful in macrophages. In hereditary hemochromatosis and posttransfusional siderosis, the iron is found predominantly in myocytes and appears to cause cell damage, whilst this is not the case in experimental iron overload in rats.

Anemia, Iron-Deficiency↗

PubMed1984

Natural killer cell activity and T subpopulations in thalassemia major.

Natural killer (NK) cell activity against K562 cell targets and the distribution of T cell subpopulations were investigated in the peripheral blood of 25 patients affected by beta thalassemia major, 18 clinically healthy heterozygotes, and 25 age-matched normal subjects. It was found that thalassemia major patients display augmented levels of NK activity [specific lysis 41.9 +/- (se) 4.5%], while thalassemic carriers behave as normal controls [specific lysis 34.6 +/- (se) 3.5%]. The increase of NK function was neither related to the splenectomy nor to the siderosis, but rather to the age and the amount of blood units that the patients had received. An imbalance of circulating T subsets with the helper/suppressor cell ratio significantly diminished (p less than 0.001) was also detected in homozygotes but not in carriers. The finding that NK function is enhanced in homozygous beta thalassemia might be of clinical interest in assessing the risk of development of malignancies in these patients.

Adolescent↗

PubMed1989

Iron, copper and zinc levels in serum and cirrhotic liver of patients with and without hepatocellular carcinoma.

It has been pointed out that hepatocellular carcinoma (HCC) develops more frequently in cirrhotic liver with siderosis than in liver without iron deposition, that excess copper in hepatocytes inhibits hepatocarcinogenesis, and that an increase in copper and a decrease in zinc are seen in the sera of patients with various malignant tumors. Iron, copper and zinc concentrations in the serum and liver were estimated in normal subjects and cirrhotic patients with and without HCC. Serum copper level was significantly higher in cirrhotic patients with or without HCC than in normal subjects. No significant differences were observed in the levels of these trace elements in the serum and liver of cirrhotic patients with and without HCC. The current study seems to indicate that iron, copper and zinc do not play an important role in the development of HCC in cirrhotic patients in Japan.

Carcinoma, Hepatocellular↗

PubMed1991

Liver iron overload and desferrioxamine treatment of porphyria cutanea tarda.

The aim of this paper is to evaluate invasive and non-invasive indices of iron store and compare the effectiveness of different ferrodepletive protocols in 150 patients with porphyria cutanea tarda (PCT). Iron removal was performed either by intensive phlebotomy (22 cases) or slow subcutaneous and high intravenous doses of desferrioxamine (18 and 5 cases, respectively), and several laboratory parameters were studied; among these, oligo-elements and urinary porphyrins (detected by HPLC) were taken into account before and after the treatments. Serum iron, transferrin saturation, ferritin (RIA) and nuclear magnetic resonance results were compared with invasive findings in order to detect the metal deposition in liver tissue (atomic absorption concentration, optic or electron-microscopic detection). Liver iron overload was observed in 95% of cases. Full normalization of the disease took place by all the treatments, even if it required slightly more time in the phlebotomy group. We may conclude that ferrodepletive treatments are highly effective in PCT and, considering the fact that siderosis and liver damage always accompany the disease, these treatments are proposed as first choice in such cases.

Bloodletting↗

PubMed1984

Porphyria cutanea tarda in beta-thalassemia trait carriers.

The authors report 5 cases of porphyria cutanea tarda (PCT) occurring in carriers of the beta-thalassemia trait. This hematologic condition may be responsible for the development of liver damage resulting in siderosis, higher susceptibility to hepatitis B virus infection, and the earlier appearance of clinical features of PCT. Consequently, the authors propose chelation therapy with long-term subcutaneous desferioxamine infusions.

Adult↗

PubMed1987

Involvement of iron and iron-catalyzed free radical production in ethanol metabolism and toxicity.

Lipoperoxidation, a degradative process of membranous polyunsaturated fatty acids, has been suggested to represent an important mechanism in the pathogenesis of ethanol toxicity on the liver and possibly also on the brain. Catalysis by transition metals, especially iron, is involved in the biosynthesis of free radicals contributing to lipid peroxidation. Although the exact nature of the redox-active iron implicated in this catalysis is still unknown, it has been well established that lipid peroxidation can be prevented in vitro by iron chelators such as desferrioxamine. Deprivation of redox-active iron through desferrioxamine inhibits by about 50% the microsomal oxidation of ethanol in vitro and reduces very significantly in vivo the overall ethanol elimination rate in rats. Administration of desferrioxamine together with ethanol also reduces the ethanol-induced disturbances in the antioxidant defense mechanisms of the hepatocyte. It also reduces in mice both the severity of physical dependence on ethanol and lethality following the acute administration of a narcotic dose of ethanol. Chronic overloading of rats with iron results, on the opposite, in an increased rate of ethanol elimination, although alcohol dehydrogenase and catalase activities are reduced and cytochrome P-450 depleted in the liver of such iron-overloaded animals. The magnitude of the ethanol-induced increase in lipid peroxidation and decrease in the major membranous antioxidant, alpha-tocopherol, is exacerbated in iron-overloaded rats. Several disturbances of iron metabolism have been reported in human alcoholics. Their contribution to ethanol toxicity appears very likely in the case of hepatic siderosis associated with alcohol abuse. Ethanol could however disturb iron metabolism even in the absence of gross abnormalities of the total iron stores. It is suggested that ethanol intoxication could increase cellular redox-active iron, thus contributing to an enhanced steady-state concentration of reactive-free radicals. This oxidative stress would lead to lipoperoxidative damage and cellular injury.

Alcoholic Intoxication↗

PubMed1976

An inherited enzymatic defect in porphyria cutanea tarda: decreased uroporphyrinogen decarboxylase activity.

Uroporphyrinogen decarboxylase activity was measured in liver and erythrocytes of normal subjects and in patients with porphyria cutanea tarda and their relatives. In patients with porphyria cutanea tarda, hepatic uroporphyrinogen decarboxylase activity was significantly reduced (mean 0.43 U/mg protein; range 0.25-0.99) as compared to normal subjects (mean 1.61 U/mg protein; range 1.27-2.42). Erythrocyte uroporphyrinogen decarboxylase was also decreased in patients with porphyria cutanea tarda. The mean erythrocyte enzymatic activity in male patients was 0.23 U/mg Hb (range 0.16-0.30) and in female patients was 0.17 U/mg Hb (range 0.15-0.18) as compared with mean values in normal subjects of 0.38 U/mg Hb (range 0.33-0.45) in men and 0.26 U/mg Hb (range 0.18-0.36) in women. With the erythrocyte assay, multiple examples of decreased uroporphyrinogen decarboxylase activity were detected in members of three families of patients with porphyria cutanea tarda. In two of these families subclinical porphyria was also recognized. The inheritance pattern was consistant with an autosomal dominant trait. The difference in erythrocyte enzymatic activity between men and women was not explained but could have been due to estrogens. This possibility was supported by the observation that men under therapy with estrogens for carcinoma of the prostate had values in the normal female range. It is proposed that porphyria cutanea tarda results from the combination of an inherited defect in uroporphyrinogen decarboxylase and an acquired factor, usually siderosis associated with alcoholic liver disease.

5-Aminolevulinate Synthetase↗

PubMed1988

Desialation of transferrin by rat liver endothelium.

To examine the role of liver endothelium in desialation of transferrin (TF), pulse-chase studies were done by incubation of either 3H (sialic acid labeled)-, or 125I, or 59Fe (protein core labeled)-TF with fractionated liver endothelium. While 125I or 59Fe labels were externalized after initial binding and internalization, a large proportion of 3H label was internalized and remained within the cell. When the supernatant of these experiments was studied by isoelectricfocusing and Ricinus communis agglutinin (RCA120) affinity chromatography, generation of asialotransferrin was noted by both techniques. Incubation of liver endothelium with double-labeled TF (sialic acids with 3H and protein core with 125I or 59Fe) led initially to a concordant uptake of the two labels, which were then dissociated and 3H was retained by the cell. These findings indicate desialation of TF by liver endothelium. The significance of these findings in the pathogenesis of hepatic siderosis is discussed.

Animals↗

PubMed1983

Insulin resistance and iron overload.

Glucose tolerance tests performed in 15 patients (10 males and 5 females, age range 6-34 years, mean 16 years) with transfusional iron overload revealed fasting and subsequent blood glucose concentrations within the normal range in all except one patients who was overtly diabetic. However, in all patients except one, blood glucose concentration at 2 hours was higher than the respective fasting glucose concentration. All but two of the patients (one of whom was diabetic) showed fasting and post glucose hyperinsulinism. All the patients had hepatic dysfunction of varying severity. It is hence suggested that the initial disturbance of carbohydrate metabolism in transfusional siderosis is insulin resistance, similar to that found in chronic liver disease. Overt diabetes is probably a later event, occurring when sufficient damage to pancreatic cells has occurred and appropriate hyperinsulinaemia cannot be sustained.

Adolescent↗

PubMed1993

Morphologic investigations of the guinea pig model of iron overload.

We have developed a guinea pig model of iron overload toxicity. Animals were administered intraperitoneal iron dextran 3 times a week to achieve total body iron load of 0.25, 0.5, 1.0, 1.5, and 2.0 g Fe/kg body weight in less than 30 days. Quantitation of tissue iron levels with atomic absorption indicated increased iron deposition in liver and heart of the iron-loaded guinea pigs (p < 0.001). Additionally, the iron-loaded pigs demonstrated decreased nuclear magnetic resonance spectroscopy T1 relaxation times in both liver and heart (p < 0.001). Serum iron, total body iron capacity, and transferrin saturation values were also determined in guinea pigs treated with 0.25, 0.5, and 1.0 g Fe/kg body weight. Serum iron and total iron-binding capacity were significantly increased at 0.5 and 1.0 g Fe/kg; transferrin saturation was elevated at 0.25 and 1.0 g Fe/kg. kg. Histologic examination of liver, heart, and bone marrow as well as ultrastructural studies on liver and heart confirmed increased iron deposition in treated animals. At the low iron dose level of 0.5 g Fe/kg, liver iron particles were primarily confined to Kupffer cells with minimal hepatocellular localization. Increased hepatocellular iron deposition was observed with larger doses of loaded iron. Myocardial iron was most prominent in interstitial cells of the epicardium, endocardium, myocardium, and coronary adipose tissue. Ultrastructurally, the presence of iron particles in perinuclear, membrane-bound structures (consistent with lysosomes) was confirmed using x-ray microanalysis. These morphological studies suggest that in this animal model siderosis of hepatic mononuclear phagocyte and myocardial interstitial cells may be the initial lesions leading to further biochemical and functional abnormalities. Correlation between tissue iron measurements and both light and electron microscopic changes, presented in this report, serve to introduce the iron-loaded guinea pig as a model for the study of iron-induced tissue damage.

Animals↗

PubMed2005

Pathology of Berkeley sickle cell mice: similarities and differences with human sickle cell disease.

Because Berkeley sickle cell mice are used as an animal model for human sickle cell disease, we investigated the progression of the histopathology in these animals over 6 months and compared these findings to those published in humans with sickle cell disease. The murine study groups were composed of wild-type mixed C57Bl/6-SV129 (control) mice and sickle cell (SS) mice (alpha-/-, beta-/-, transgene +) of both sexes and between 1 and 6 months of age. SS mice were similar to humans with sickle cell disease in having erythrocytic sickling, vascular ectasia, intravascular hemolysis, exuberant hematopoiesis, cardiomegaly, glomerulosclerosis, visceral congestion, hemorrhages, multiorgan infarcts, pyknotic neurons, and progressive siderosis. Cerebral perfusion studies demonstrated increased blood-brain barrier permeability in SS mice. SS mice differed from humans with sickle cell disease in having splenomegaly, splenic hematopoiesis, more severe hepatic infarcts, less severe pulmonary manifestations, no significant vascular intimal hyperplasia, and only a trend toward vascular medial hypertrophy. Early retinal degeneration caused by a homozygous mutation (rd1) independent from that causing sickle hemoglobin was an incidental finding in some Berkeley mice. While our study reinforces the fundamental strength of this model, the notable differences warrant careful consideration when drawing parallels to human sickle cell disease.

Anemia, Sickle Cell↗

PubMed2004

Hematoma removal, heme, and heme oxygenase following hemorrhagic stroke.

The hemorrhagic strokes, intracerebral (ICH) and subarachnoid hemorrhage (SAH), often have poor outcomes. Indeed, the most common hemorrhagic stroke, ICH, has the highest mortality and morbidity rates of any stroke subtype. In this report, we discuss the evidence for the staging of red blood cell removal after ICH and the significance of control of this process. The protective effects of clinically relevant metalloporphyrin heme oxygenase inhibitors in experimental models of ICH and in superficial siderosis are also discussed. We also examine literature paradoxes related to both heme and heme oxygenase in various disorders of the central nervous system. Last, new data are presented that support the concept that heme, although primarily a pro-oxidant, can also have antioxidant properties.

Animals↗