Low hepatic iron concentration: evaluation of two complementary methods, colorimetric assay and iron histological scoring

Histological Scores Validate the Accuracy of Hepatic Iron Load Measured by Signal Intensity Ratio and R2* Relaxometry MRI in Dialysis Patients

Almost all haemodialysis patients are treated with parenteral iron to compensate for blood loss and to allow the full therapeutic effect of erythropoiesis-stimulating agents. Iron overload is an increasingly recognised clinical situation diagnosed by quantitative magnetic resonance imaging (MRI). MRI methods have not been fully validated in dialysis patients. We compared Deugnier’s and Turlin’s histological scoring of iron overload and Scheuer’s classification (with Perls’ stain) with three quantitative MRI methods for measuring liver iron concentration (LIC)—signal intensity ratio (SIR), R2* relaxometry, and R2* multi-peak spectral modelling (Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation (IDEAL-IQ^®)) relaxometry—in 16 haemodialysis patients in whom a liver biopsy was formally indicated for medical follow-up. LIC MRI with these three different methods was highly correlated with Deugnier’s and Turlin’s histological scoring (SIR: r = 0.8329, p = 0.0002; R2* relaxometry: r = −0.9099, p < 0.0001; R2* relaxometry (IDEAL-IQ^®): r = −0.872, p = 0.0018). Scheuer’s classification was also significantly correlated with these three MRI techniques. The positive likelihood ratio for the diagnosis of abnormal LIC by Deugnier’s histological scoring was > 62 for the three MRI methods. This study supports the accuracy of quantitative MRI methods for the non-invasive diagnosis and follow-up of iron overload in haemodialysis patients.

Liver R2* is affected by both iron and fat: A dual biopsy-validated study of chronic liver disease

BACKGROUND

Liver iron content (LIC) in chronic liver disease (CLD) is currently determined by performing an invasive liver biopsy. MRI using R2* relaxometry is a noninvasive alternative for estimating LIC. Fat accumulation in the liver, or proton density fat fraction (PDFF), may be a possible confounder of R2* measurements. Previous studies of the effect of PDFF on R2* have not used quantitative LIC measurement.

PURPOSE

To assess the associations between R2*, LIC, PDFF, and liver histology in patients with suspected CLD.

STUDY TYPE

Prospective.

POPULATION

Eighty-one patients with suspected CLD.

FIELD STRENGTH/SEQUENCE

1.5 T. Multiecho turbo field echo to quantify R2*. PRESS MRS to quantify PDFF.

ASSESSMENT

Each patient underwent an MR examination, followed by two needle biopsies immediately following the MR examination. The first biopsy was used for conventional histological assessment of LIC, whereas the second biopsy was used to quantitatively measure LIC using mass spectrometry. R2* was correlated with both LIC and PDFF. A correction for the influence of fat on R2* was calculated.

STATISTICAL TESTS

Pearson correlation, linear regression, and area under the receiver operating curve.

RESULTS

There was a positive linear correlation between R2* and PDFF (R = 0.69), after removing data from patients with elevated iron levels, as defined by LIC. R2*, corrected for PDFF, was the best method for identifying patients with elevated iron levels, with a correlation of R = 0.87 and a sensitivity and specificity of 87.5% and 98.6%, respectively.

DATA CONCLUSION

PDFF increases R2*.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:325-333.

Long-Term High-Fat Diet Decreases Hepatic Iron Storage Associated with Suppressing TFR2 and ZIP14 Expression in Rats

High-fat diet-induced obesity is known to disturb hepatic iron metabolism in a time-dependent manner. The mechanism of decreased hepatic iron deposits induced by long-term high-fat diet needs to be further investigated. In this study, 24 6-week-old male Sprague-Dawley rats were given a 16-week high-fat diet and hepatic iron metabolism was examined. High-fat diet feeding considerably decreased hepatic iron contents, enhanced transferrin expression, and reduced the expression of ferritin heavy chain, ferritin light chain, and hepatic iron uptake-related proteins (transferrin receptor 2, TFR2, and ZRT/IRT-like protein 14, ZIP14) in rats. Impaired expression of hepatic TFR2 coincided with DNA hypermethylation on the promoter and repressed expression of transcription factor hepatocyte nuclear factor 4α (HNF4α). miR-181 family expression was markedly increased and verified to regulate Zip14 expression by the dual-luciferase reporter system. Taken together, long-term high-fat diet decreases hepatic iron storage, which is closely linked to inhibition of liver iron transport through the TFR2 and ZIP14-dependent pathway.

Hepatic iron overload is associated with hepatocyte apoptosis during Clonorchis sinensis infection

Background

Hepatic iron overload has been implicated in many liver diseases; however, whether it is involved in clonorchiasis remains unknown. The purpose of this study is to investigate whether Clonorchis sinensis (C. sinensis) infection causes hepatic iron overload, analyze the relationship between the iron overload and associated cell apoptosis, so as to determine the role of excess iron plays in C. sinensis-induced liver injury.

Methods

The Perls’ Prussian staining and atomic absorption spectrometry methods were used to investigate the iron overload in hepatic sections of wistar rats and patients infected with C. sinensis. The hepatic apoptosis was detected by transferase uridyl nick end labeling (TUNEL) methods. Spearman analysis was used for determining the correlation of the histological hepatic iron index and the apoptotic index.

Results

Blue iron particles were deposited mainly in the hepatocytes, Kupffer cells and endothelial cells, around the liver portal and central vein area of both patients and rats. The total iron score was found to be higher in the infected groups than the respective control from 8 weeks. The hepatic iron concentration was also significantly higher in treatment groups than in control rats from 8 weeks. The hepatocyte apoptosis was found to be significantly higher in the portal area of the liver tissue and around the central vein. However, spearman’s rank correlation coefficient revealed that there was a mildly negative correlation between the iron index and hepatocyte apoptosis.

Conclusions

This present study confirmed that hepatic iron overload was found during C. sinensis infection. This suggests that iron overload may be associated with hepatocyte apoptosis and involved in liver injury during C. sinensis infection. Further studies are needed to investigate the molecular mechanism involved here.

Introducing a new histologic scoring system for iron deposition in liver of thalassemic patients, compared with atomic absorption spectrometry

Iron deposition in liver is a major finding in thalassemic patients and because of direct iron toxicity to liver it is associated with several consequences for example liver fibrosis. Liver biopsies from 63 patients were evaluated, 40 (63.5%) were male and 20 (36.5%) were female. The mean age of the patients was 8.01 ± 3.7 and the age range was from 1.8 to 15 years. Histologic grading and staging was performed for each case according to modified HAI (Hepatitis Activity Index) system. Iron scoring was performed according to Sindram & Marx and MTK1-3 scoring systems. The mean (SD) dry weight (dw) of liver specimens was 1.34 (0.11) mg (range 0.20 to 3.80 mg). The mean (SD) of hepatic iron concentration was 230.9 (121.2)μmol/g dry weight. The relationship between the variables HIC, HII (hepatic iron index) and all histological gradings of iron (S&M and MTK1-3) was very strong. The relationship between the HIC and staging by HAI method was good. Significant differences were identified between the mean HIC in scores 1&2 of all histological iron scorings (S&M and MTK1-3), but no significant differences identified between mean HIC in other adjacent scores in all histological iron scorings (S&M and MTK1, 2 and 3). New scoring system introduced by us in this study which considered size and density of iron granules as well as zone of iron deposition was very much the same as simple Sindram and Marx classification.

Iron Overload in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Context.—Patients who undergo hematopoietic stem cell transplant are at an increased risk of developing iron overload.

Objectives.—To describe the effect of hepatic iron overload on hematopoietic stem cell transplant recipients and to validate the utility of histologic scoring system of iron granules in the liver.

Design.—Records of 154 post allogeneic hematopoietic stem cell transplant patients were reviewed. Forty-nine patients underwent liver biopsy. Histologic hepatic iron overload was defined as a score of 2 or greater (scale, 0–4).

Results.—Twenty-eight of 49 patients (57%) evaluated by liver biopsy had hepatic iron overload; 17 had moderate to severe hepatic iron overload (score, 3 or 4). In multivariate analysis, a significant correlation was discovered between hepatic iron overload and the number of transfusions (P &lt; .001), posttransplant serum ferritin levels (P  =  .004), lactate dehydrogenase levels (P  =  .03), and the development of blood stream infections (P  =  .02). There was no correlation between hepatic iron overload and abnormal liver function test results. While 37 patients (76%) died after receiving a transplant, mortality was not influenced by hepatic iron overload but was significantly higher in older patients, in patients with lower serum albumin levels, higher serum bilirubin levels, and higher clinical grade of acute graft-versus-host disease (P  =  .04, P  =  .001, P  =  &lt;.001, and P  =  .004, respectively).

Conclusions.—Hepatic iron overload is commonly identified in hematopoietic stem cell transplant patients and can be accurately diagnosed by liver biopsy. In addition, hepatic iron overload has been identified in patients receiving as few as 25 units of packed red blood cells, with elevated posttransplant serum ferritin levels, and with blood stream infections.

Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

OBJECTIVES/METHODS

This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or beta-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC).

RESULTS

In patients with baseline LIC > or = 7 mg Fe/g dry weight, deferasirox initiated at 20 or 30 mg/kg/d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 +/- 0.14 mg/kg/d; greatest in DBA: 0.4 +/- 0.11 mg/kg/d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety/tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases.

CONCLUSIONS

Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups.

Iron chelation beyond transfusion iron overload

The effects of systemic iron overload in hereditary (e.g., classic HFE hemochromatosis) or acquired disorders (e.g., transfusion-dependent iron overload) are well known. Several other iron overload diseases, with an observed mild-to-moderate increase in iron in selected organs (e.g., the liver or the brain), or with "misdistribution" of iron within cells (e.g., reticuloendothelial cells) or subcellular organelles (e.g., mitochondria), have been recognized more recently. The deleterious impact of any excess iron may be high as active redox iron may directly contribute to cell damage or affect signaling pathways involved in cell necrosis-apoptosis or organ fibrosis and cancer. This article discusses the potential use of iron chelation therapy to treat iron overload from causes other than transfusion overload.

Pathology of hepatic iron overload

Although progress in imaging and genetics allow for a noninvasive diagnosis of most cases of genetic iron overload, liver pathology remains often useful (1) to assess prognosis by grading fibrosis and seeking for associated lesions and (2) to guide the etiological diagnosis, especially when no molecular marker is available. Then, the type of liver siderosis (parenchymal, mesenchymal or mixed) and its distribution throughout the lobule and the liver are useful means for suggesting its etiology: HLA-linked hemochromatosis gene (HFE) hemochromatosis or other rare genetic hemochromatosis, nonhemochromatotic genetic iron overload (ferroportin disease, aceruloplasminemia), or iron overload secondary to excessive iron supply, inflammatory syndrome, noncirrhotic chronic liver diseases including dysmetabolic iron overload syndrome, cirrhosis, and blood disorders.

Iron overload disorders

Because hepatic siderosis is a frequent finding, there is a risk of making it trite when elaborating the pathology report. Iron is increasingly considered an important cofactor of morbidity. Its finding in hepatic cells must be recognized, indicated, qualified, quantified, and interpreted. A systematic reasoning based on a strict semiological approach allows for guiding the clinician. Iron overload syndromes do not amount to genetic hemochromatosis only.

Liver fibrosis in overweight patients

BACKGROUND & AIMS

A common clinical issue is whether overweight patients with abnormal liver function test results should undergo liver biopsy. Although serious liver injury can occur, its prevalence and risk factors are not well known.

METHODS

Ninety-three consecutive patients with abnormal liver function tests (but without overt liver disease), body mass index (BMI) > 25 kg/m(2), and no alcoholic, viral, autoimmune, drug-induced, or genetic liver disease were retrospectively studied. Clinical, biological, and histological variables were tested for association with septal fibrosis or cirrhosis.

RESULTS

Septal fibrosis was present in 28 patients (30%) including cirrhosis in 10 (11%). Age >/= 50 years (odds ratio [OR], 14.1), BMI >/= 28 kg/m(2) (OR, 5.7), triglycerides >/= 1.7 mmol/L (OR, 5), and alanine aminotransferase (ALT) >/= 2N (OR, 4.6) were independently associated with septal fibrosis. Among histological features, septal fibrosis was strongly associated with necroinflammatory activity (OR, 44). A score combining age, BMI, triglycerides, and ALT had 100% negative predictive value for septal fibrosis when scoring 0 or 1 (100% sensitivity for a specificity of 47%).

CONCLUSIONS

Septal fibrosis occurs frequently in overweight patients with abnormal liver function tests. A clinicobiological score combining BMI, age, ALT, and triglycerides could improve selection of patients for liver biopsy.