June W. Halliday

Prevalence of haemochromatosis amongst asymptomatic Australians

We determined the prevalence of iron overload due to homozygous haemochromatosis in an asymptomatic Australian (predominantly Caucasian) population by surveying 1968 employees of two large corporations. Subjects were screened by measurement of transferrin saturation and serum ferritin concentration and, in all subjects with elevation of both indices, percutaneous liver biopsy was performed to establish whether significant iron overload was present. The prevalence of iron overload due to haemochromatosis in this population was 0·36%. The prevalence rate was not significantly different between males and females, suggesting that this autosomal recessive disease is expressed equally in females given an adequate dietary iron supply. The positive predictive value of a transferrin saturation consistently >45% together with an elevated serum ferritin concentration was 64%. It is concluded that the prevalence of significant iron overload due to homozygous haemochromatosis warranting treatment is approximately 1:300 and that transferrin saturation should be included in existing adult health screening programmes.

Primary liver cancer in genetic hemochromatosis: A clinical, pathological, and pathogenetic study of 54 cases

BACKGROUND Although liver cancer arises frequently in the course of genetic hemochromatosis (GH), it has not been previously studied in a large series of patients with well-defined GH. METHODS The bioclinical and pathological data from 1 cholangiocarcinoma and 53 hepatocellular carcinomas (HCCs) complicating GH in 32 untreated and 22 de-ironed patients are reported. RESULTS This study (1) adds three new well-documented cases of HCC in noncirrhotic but only fibrotic hemochromatotic liver, (2) shows the high prevalence (83%) of proliferative and often dysplastic (70%) iron-free foci in the nontumorous liver of untreated patients, and (3) emphasizes the significant increase of cirrhosis (81% vs. 28%) and of associated noniron-related risk factors, mainly chronic alcoholism (48% vs. 25%) and tobacco smoking (50% vs. 18%) in patients with HCC compared with matched hemochromatotic patients without HCC. CONCLUSIONS These data (1) suggest that iron-free foci may be markers of an early stage of HCC in GH and (2) supply the basis for defining a cost-effective policy for the screening of HCC in GH patients.

Distribution of transferrin saturation in an Australian population: relevance to the early diagnosis of hemochromatosis.

BACKGROUND & AIMS An elevated transferrin saturation is the earliest phenotypic abnormality in hereditary hemochromatosis. Determination of transferrin saturation remains the most useful noninvasive screening test for affected individuals, but there is debate as to the appropriate screening level. The aims of this study were to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals and to evaluate potential transferrin saturation screening levels. METHODS Statistical mixture modeling was applied to data from a survey of asymptomatic Australians to estimate the mean transferrin saturation in hemochromatosis heterozygotes and normal individuals. To evaluate potential transferrin saturation screening levels, modeling results were compared with data from identified hemochromatosis heterozygotes and homozygotes. RESULTS After removal of hemochromatosis homozygotes, two populations of transferrin saturation were identified in asymptomatic Australians (P < 0.01). In men, 88.2% of the truncated sample had a lower mean transferrin saturation of 24.1%, whereas 11.8% had an increased mean transferrin saturation of 37.3%. Similar results were found in women. A transferrin saturation threshold of 45% identified 98% of homozygotes without misidentifying any normal individuals. CONCLUSIONS The results confirm that hemochromatosis heterozygotes form a distinct transferrin saturation subpopulation and support the use of transferrin saturation as an inexpensive screening test for hemochromatosis. In practice, a fasting transferrin saturation of > or = 45% identifies virtually all affected homozygous subjects without necessitating further investigation of unaffected normal individuals.

THE NATURE OF PIECEMEAL NECROSIS IN CHRONIC ACTIVE HEPATITIS

On the basis of histological studies, it is proposed that the type of liver-cell death in piecemeal necrosis is apoptosis. The characteristic inconspicuousness of apoptosis explains why the mode of hepatocyte elimination in piecemeal necrosis has hitherto remained obscure. Cell-mediated immune attack induces apoptosis, not classical necrosis, and the occurrence of apoptosis in piecemeal necrosis links the observed morphological changes in chronic active hepatitis with the other evidence for an autoimmune pathogenesis. It is significant that apoptosis does not evoke inflammation or fibroplasia. In attempting to elucidate the cause of the fibrosis that accompanies progression to cirrhosis in chronic hepatitis, it may thus be more relevant to study the effect on fibroblasts of substances liberated during lymphocyte-hepatocyte interactions than the death of the hepatocytes.

Body Composition in Nonalcoholic Cirrhosis: The Effect of Disease Etiology and Severity on Nutritional Compartments

BACKGROUND/AIMS Previous studies of body composition in cirrhosis have either measured only one body compartment, used alcoholic subjects, or not corrected body composition for physical characteristics. The aim of this study was to perform a detailed analysis of body composition in subjects with nonalcoholic cirrhosis. METHODS Simultaneous measurements of total body potassium and total body water were performed and values of body cell mass and body fat were corrected for physical characteristics. RESULTS Childs class C patients had a significantly lower mean total body potassium index (i.e., percent observed value/expected value) and body fat index than class A or B patients. Eighty-one percent of class C patients had simultaneous reductions in body fat and body cell mass, and 71% of patients with class A disease had a significant reduction in either or both compartments. Nine patients showed the pattern of tissue loss seen with short-term starvation. Fourteen patients showed the pattern of tissue loss seen in physiological stress. CONCLUSIONS Severe liver disease is characterized by significant reductions in body fat and body cell mass, most class A patients have a significant reduction in some nutritional compartments, and the pattern of tissue loss may reflect mechanisms of tissue wasting.

Dose‐dependent pharmacokinetics of caffeine in humans: Relevance as a test of quantitative liver function

Caffeine clearance was determined in 13 healthy control subjects and in 13 patients with histologically proven cirrhosis. On separate occasions, 70 mg, 200 mg, and 300 mg single doses of anhydrous caffeine were administered orally with decaffeinated coffee to each subject. Subjects were analyzed individually, acting as their own controls, thus reducing interindividual variability. The present study showed that caffeine exhibited dose‐dependent pharmacokinetics, particularly in subjects who showed high initial clearance with the low dose (70 mg) of caffeine. There was a significant decrease in caffeine clearance with increasing dose from 70 mg to 300 mg (n = 26, p < 0.01, Dunnetts test), indicating saturable caffeine metabolism in the dose range tested. These findings imply that if caffeine is to be used as a guide to deteriorating liver function, serial caffeine clearance estimations should be performed in each individual subject, with use of the same dose of caffeine each time.

Expression of hemochromatosis in homozygous subjects: Implications for early diagnosis and prevention

This study looks at expression of genetic hemochromatosis in the homozygous and heterozygous states. Two hundred nine subjects in 40 families with confirmed hemochromatosis and clear evidence of HLA linkage in symptomatic individuals were studied prospectively for up to 24 yr. The study group consisted of 40 probands, 51 subjects sharing two HLA haplotypes with affected relatives (putative homozygotes), 98 putative heterozygotes, and 20 putative normal homozygotes. Forty-eight of 51 subjects predicted to be homozygous showed increased hepatic iron stores as assessed by liver biopsy and quantitative phlebotomy. If not evident initially, this developed in 1-8 yr. In the 3 subjects predicted by HLA typing to be homozygous but in whom there was no progressive iron accumulation, results of studies using another chromosome 6 genetic marker (Factor 13 A subunit) were consistent with chromosomal recombination, presumably separating one hemochromatosis allele from the HLA markers. No heterozygous subject developed overt hemochromatosis during the period of follow-up, although 1 showed evidence of iron overload at initial assessment. Genetic recombination is again thought to have separated the hemochromatosis allele from the HLA markers here. The present findings favor a location of the hemochromatosis locus telomeric to HLA-A. It is concluded that, in this population, hemochromatosis is apparently always HLA linked, and homozygous subjects will develop iron overload in the absence of chromosomal recombination or blood loss.

Normal Serum Ferritin Concentrations in Precirrhotic Hemochromatosis

We investigated 33 of 58 members of two families with latent or precirrhotic hemochromatosis to determine its pattern of inheritance and to evaluate the serum ferritin levels as an index of iron stores. In both families, the pattern of inheritance was as an autosomal dominant trait with incomplete expressivity. Mean serum ferritin values in the affected family members were 88.5 ng per milliliter (range, 28.0 to 201.9) for males and 65.2 ng per milliter (range 23.7 to 97.0) for females, which were no different from controls (P is less than 0.5). Furthermore, the serum ferritin values did not correlate with or reflect mobilizable iron stores, and there were no relations between the serum iron, iron-binding capacity and transferrin saturation (P is less than 0.2). Thus, serum ferritin concentrations in precirrhotic familial hemochromatosis appear to underestimate iron stores. Serum ferritin levels do not help to identify such patients with increased iron stores for therapeutic phlebotomy.

Evidence that myofibroblast-like cells are the cellular source of capsular collagen in hepatocellular carcinoma

BACKGROUND/AIMS The prognosis for patients with hepatocellular carcinoma is poor although tumour encapsulation has been associated with improved survival and disease-free rates. While the source of the tumour capsule is unclear, the major role that activated hepatic stellate cells play in the deposition of liver matrix in normal and diseased states suggests the possible involvement of these cells in tumour encapsulation. METHODS Twenty-four liver tumours (seven encapsulated HCC, seven non-encapsulated HCC, 10 colorectal metastases) were studied. Activated hepatic stellate cells were identified by immunohistochemistry for alpha-smooth muscle actin (alpha-SMA) and in situ hybridization for pro-collagen alpha1 (I) mRNA. Collagen deposition was localized using Massons trichrome stain. RESULTS Pro-collagen alpha1 (I) mRNA co-localized to alpha-SMA positive hepatic stellate cells within the region of increased collagen deposition in (i) the tumour capsule of encapsulated HCC, and (ii) the tumour junction of non-encapsulated HCC and colorectal metastasis. In addition, there was marked peritumour expression of alpha-SMA and procollagen alpha1 (I) mRNA, which diminished with distance away from the tumour in all tumour groups. The degree of expression was greatest with encapsulated HCC, less with non-encapsulated HCC and least with colorectal metastasis. This contrasted with the absence of alpha-SMA expression in normal liver from the same patients. Within the tumours, colorectal metastases differed from HCC by demonstrating marked alpha-SMA expression and collagen deposition in the septa. CONCLUSIONS Our findings demonstrate that activated hepatic stellate cells (i) are responsible for increased peritumour collagen production in non-encapsulated HCC and colorectal metastasis, and (ii) may be implicated in tumour capsule formation in HCC and metastasis stroma development. Thus, stellate cells may influence the local hepatic invasion by these tumours.

Transferrin receptor distribution and regulation in the rat small intestine: Effect of iron stores and erythropoiesis

A combination of biochemical quantitation and immunohistochemistry has been used to examine in detail transferrin receptor distribution and expression in the rat small intestine and its relationship to iron absorption. Receptor numbers were quantitated by transferrin binding to preparations of basolateral or brush-border membranes. Receptors were demonstrated on the basolateral membranes of the gut cells, but not on the brush-border fraction. Apotransferrin demonstrated little binding to basolateral membranes at physiological pH. Dietary or parenteral iron loading of animals produced a significant decline in transferrin binding, whereas binding was increased in iron deficiency. These data were confirmed by immunohistochemical studies using a monoclonal antibody to the transferrin receptor. When iron absorption was increased threefold following acute hemolysis and without a decrease in body iron stores, there was no change in transferrin receptor number. These data indicate that intestinal transferrin receptors may be regulated by body iron stores but suggest that they are not directly involved in iron absorption.