Serum procollagen III peptide concentration in iron overload

Non-invasive methods for liver fibrosis prediction in hemochromatosis: One step beyond

Advances in recent years in the understanding of, and the genetic diagnosis of hereditary hemochromatosis (HH) have changed the approach to iron overload hereditary diseases. The ability to use a radiologic tool (MRI) that accurately provides liver iron concentration determination, and the presence of non-invasive serologic markers for fibrosis prediction (serum ferritin, platelet count, transaminases, etc), have diminished the need for liver biopsy for diagnosis and prognosis of this disease. Consequently, the role of liver biopsy in iron metabolism disorders is changing. Furthermore, the irruption of transient elastography to assess liver stiffness, and, more recently, the ability to determine liver fibrosis by means of MRI elastography will change this role even more, with a potential drastic decline in hepatic biopsies in years to come. This review will provide a brief summary of the different non-invasive methods available nowadays for diagnosis and prognosis in HH, and point out potential new techniques that could come about in the next years for fibrosis prediction, thus avoiding the need for liver biopsy in a greater number of patients. It is possible that liver biopsy will remain useful for the diagnosis of associated diseases, where other non-invasive means are not possible, or for those rare cases displaying discrepancies between radiological and biochemical markers.

Diagnosis of liver fibrosis using FibroScan and other noninvasive methods in patients with hemochromatosis: a prospective study

BACKGROUND

The role of hepatic iron overload in the development of hepatic fibrosis in patients with hemochromatosis is well-established. Transient elastography (FibroScan) is a new noninvasive, rapid, reproducible bedside method, allowing assessment of liver fibrosis by measuring liver rigidity.

OBJECTIVES

The aim of this prospective study was to evaluate liver fibrosis with FibroScan and other noninvasive biochemical methods in patients with hemochromatosis (C282Y homozygosity) compared with control patients.

PATIENTS AND METHODS

From January 2004 through October 2006, all consecutive patients with hemochromatosis were evaluated for liver fibrosis using noninvasive methods (FibroScan and biochemical markers). These patients were compared with patients who had chronic cytolysis and no fibrosis on liver biopsy.

RESULTS

One hundred and three consecutive patients (57 cases and 46 controls) were fully investigated. Median FibroScan values were similar in both groups, 5.20 kPa versus 4.9 kPa, respectively. No differences were observed between cases and controls for all biochemical markers. A strong correlation was observed between FibroScan and many biochemical markers, although ferritin levels did not correlate with FibroScan values. The prevalence of patients with FibroScan values greater than 7.1 kPa (cut-off level for significant fibrosis) was 22.8% in patients with hemochromatosis and 0% in the controls (P<0.0001).

CONCLUSION

FibroScan and biochemical markers could be reliable noninvasive methods for detecting liver fibrosis in patients with hemochromatosis. Such patients have high FibroScan values more often than do control patients. Further longitudinal and prospective studies are necessary to confirm these preliminary data.

Treatment of hepatitis C virus infection in thalassemia

Treatment of hepatitis C virus (HCV) in the general population has improved over the last decade. Patients treated with peginterferon alfa (PegIFN) and ribavirin (RBV) combination therapy demonstrate overall 50-55% sustained viral response (SVR) with rates as high as 80% in patients with genotypes 2 and 3. Because RBV induces hemolysis and subsequently increases blood transfusion requirements, combination therapy has been considered contraindicated for hemoglobinopathies. This report reviews the response to interferon alfa and RBV (IFN/RBV) and PegIFN/RBV combination therapies in patients treated in the Northern California Comprehensive Thalassemia Center. A total of six thalassemia major patients were treated with IFN/RBV (n = 5; age: 4-38 years) or with PegIFN/RBV (n = 1; age: 26 years). Quantitative HCV RNA polymerase chain reaction and liver iron level assessment were completed. Transfusion volumes were obtained from patients' medical records. On IFN/RBV combination, four of five patients demonstrated SVR. The one patient on PegIFN/RBV showed end-treatment viral response after 6 months of therapy (genotype 3), but subsequently relapsed. Liver iron pretreatment level ranged from 0.2 to 22 mg/g dry weight, with a mean +/- SD of 7.9 +/- 7.7. Transfusion requirement increased by a median of 43.5% (range: 32-137%). Five of the six patients had liver iron measurements within 1 year following completion of treatment, with quantitative liver iron increasing in two patients by 2.5 mg/g dry weight, decreasing in two patients by 3 and 14 mg/g dry weight, and remaining unchanged in one patient. All patients were able to complete combination therapy, although dose reductions were required. Patients with thalassemia and high iron overload can obtain SVR after combination therapy with rates similar to those in the general population and without significant complications. Although transfusion requirements increased in most patients, iron burden was not necessarily increased.

Comparison of organ dysfunction in transfused patients with SCD or beta thalassemia

Although it is life saving, transfusion therapy has resulted in the majority of sickle cell anemia and thalassemia patients being at risk for hemosiderosis-induced organ damage. It is unknown whether the complications of iron overload are affected by the underlying disease. In order to address this problem, we compared the prevalence of organ dysfunction in both groups of patients receiving chronic transfusion therapy (beta thalassemia, N = 30; sickle cell anemia, N = 43). Both groups had similar quantitative liver iron. Thalassemia patients had greater cardiac disease (20% vs. 0%), growth failure (27% vs. 9%), and endocrine failure (37% vs. 0%). The strongest predictors of combined endocrine and cardiac disease in multivariate analysis were duration of chronic transfusion (P = 0.03) and diagnosis (P = 0.03). Quantitative liver iron concentration on a single liver biopsy was not predictive of cardiac or endocrine injury. Viral hepatitis is the strongest predictor of hepatocellular damage (P = 0.009), while the development of liver fibrosis is more closely related to liver iron concentration (P = 0.04). In conclusion, sickle cell anemia and thalassemia differ in the prevalence of organ injury. This difference is related to the duration of iron exposure and the specific hemoglobinopathy. A prospective study with a larger number of subjects is needed to confirm the relationships between specific diagnosis, liver iron concentration over time, and organ dysfunction.

Elevated serum type IV collagen: a sensitive indicator of the presence of cirrhosis in haemochromatosis

BACKGROUND/AIM

Hereditary haemochromatosis can now be diagnosed by genetic testing, although determining the presence or absence of cirrhosis remains crucial to patient management. While many studies have investigated the utility of various serum markers of cirrhosis in chronic liver diseases, few have examined specifically patients with hereditary haemochromatosis. The aim of this study was to assess the utility of serum type IV collagen and serum laminin in diagnosing hepatic fibrosis and cirrhosis in patients with hereditary haemochromatosis.

METHODS

The study group consisted of 42 patients with hereditary haemochromatosis and 19 Caucasian controls. Serum type IV collagen, laminin, matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of metalloproteinase (TIMP-1) concentrations were measured by enzyme-linked immunosorbant assay in serum from patients with haemochromatosis and control subjects. Liver biopsies from patients with haemochromatosis were graded for fibrosis and correlated with serum markers of hepatic fibrosis.

RESULTS

Serum type IV collagen concentration was significantly increased in haemochromatosis patients compared to controls (130+/-79 ng/ml vs 81 +/- 17 ng/ml, p<0.05) and was significantly correlated with both the grade of histological fibrosis (r=0.67, p<0.0001) and serum MMP-2 levels (r=0.42, p<0.05). A serum type IV collagen concentration > 115 ng/ml (mean+2 SD of controls) was 100% sensitive and 69% specific in detecting severe (grade 3) fibrosis and cirrhosis. The sensitivity results of serum laminin and TIMP-1 were 11% and 56% respectively.

CONCLUSIONS

Elevated serum type IV collagen is a sensitive indicator of the presence of severe fibrosis and cirrhosis in patients with haemochromatosis. Useful markers of hepatic fibrosis in other chronic liver diseases may not be applicable to haemochromatosis.

Iron loading of isolated rat hepatocytes inhibits asialoglycoprotein receptor dynamics and induces formation of rat hepatic lectin-1 [correction of leptin-1] (RHL-1) oligomers

The major subunit [rat hepatic lectin-1 (RHL-1)] of the asialoglycoprotein (ASGP) receptor mediates endocytosis of the iron-binding protein lactoferrin (Lf) by isolated rat hepatocytes, yet iron loading of cultured adult rat hepatocytes increases the binding and endocytosis of Lf while greatly inhibiting the uptake of desialylated ligand. In the present study, we determined whether the iron-induced Lf-binding site is RHL-1 and examined the nature of the iron-induced block in ASGP receptor endocytic function. Isolated rat hepatocytes increased their non-haem iron content from 70 to 470 p.p. b. following incubation with ferric ammonium citrate (<=100 microgram/ml). These conditions blocked internalization of 125I-asialo-orosomucoid (ASOR) by approximately 90% but increased 125I-Lf endocytosis by 40%. ASOR and anti-RHL-1 sera blocked the binding and endocytosis of 125I-Lf on control cells but not on iron-loaded cells, indicating that the iron-induced Lf-binding site on hepatocytes is not RHL-1. Iron-loading of hepatocytes in the presence or absence of excess ASOR did not significantly alter the number of active ASGP receptors on the cell surface. In contrast, iron-loading decreased the number of active intracellular receptors by 40% and blocked the uptake of 125I-ASOR prebound to the cells by approximately 80%. Under these conditions, we found an iron-dependent evolution of 88 and 140 kDa RHL-1-containing, beta-mercaptoethanol-sensitive multimers that constituted up to 34 and 23%, respectively, of total immunodetectable RHL-1. We propose that iron-induced formation of cystinyl-linked RHL-1-containing multimers inhibits ASGP receptor movement between cell surface and interior and disrupts acylation of intracellular receptors.