Unsaturated iron binding capacity and transferrin saturation are equally reliable in detection of HFE hemochromatosis

An efficient machine learning-based approach for screening individuals at risk of hereditary haemochromatosis

Hereditary haemochromatosis (HH) is an autosomal recessive disease, where HFE C282Y homozygosity accounts for 80–85% of clinical cases among the Caucasian population. HH is characterised by the accumulation of iron, which, if untreated, can lead to the development of liver cirrhosis and liver cancer. Since iron overload is preventable and treatable if diagnosed early, high-risk individuals can be identified through effective screening employing artificial intelligence-based approaches. However, such tools expose novel challenges associated with the handling and integration of large heterogeneous datasets. We have developed an efficient computational model to screen individuals for HH using the family study data of the Hemochromatosis and Iron Overload Screening (HEIRS) cohort. This dataset, consisting of 254 cases and 701 controls, contains variables extracted from questionnaires and laboratory blood tests. The final model was trained on an extreme gradient boosting classifier using the most relevant risk factors: HFE C282Y homozygosity, age, mean corpuscular volume, iron level, serum ferritin level, transferrin saturation, and unsaturated iron-binding capacity. Hyperparameter optimisation was carried out with multiple runs, resulting in 0.94 ± 0.02 area under the receiving operating characteristic curve (AUCROC) for tenfold stratified cross-validation, demonstrating its outperformance when compared to the iron overload screening (IRON) tool.

Evaluation of the mobile phone electromagnetic radiation on serum iron parameters in rats

BACKGROUND

Electromagnetic fields (EMF) created by mobile phones during communication have harmful effects on different organs.

OBJECTIVES

It was aimed to investigate the effects of an EMF created by a mobile phone on serum iron level, ferritin, unsaturated iron binding capacity and total iron binding capacity within a rat experiment model.

METHODS

A total of 32 male Wistar albino rats were randomly divided into the control, sham, mobile phone speech (2h/day) and stand by (12 h/day) groups. The speech and stand by groups were subjected to the EMF for a total of 10 weeks.

RESULTS

No statistically significant difference was observed between the serum iron and ferritin values of the rats in the speech and stand by groups than the control and sham groups (p>0.05). The unsaturated iron binding capacity and total iron capacity values of the rats in the speech and stand by groups were significantly lower in comparison to the control group (p<0.01).

CONCLUSION

It was found that exposure to EMF created by mobile phones affected unsaturated iron binding capacity and total iron binding capacity negatively.

Iron Binding and Iron Removal Efficiency of Desferrioxamine Based Polymeric Iron Chelators: Influence of Molecular Size and Chelator Density

Desferrioxamine (DFO) is a clinically approved, high affinity iron chelator used for the treatment of iron overload. Due to its short half-life and toxicity, DFO is administered for 8-12 h per day, 5-7 d per week. In this manuscript, the influence of molecular properties of hyperbranched polyglycerol (HPG)-DFO conjugates on their iron binding by isothermal titration calorimetry, iron removal efficiency from ferritin in presence and absence of a low molecular weight (MW) iron chelator, and protection against iron mediated oxidation of proteins is reported. The iron binding properties of HPG-DFO are slightly altered with size and DFO density of conjugates. The lower MW conjugate shows greater iron removal efficiency at room temperature, however, the efficacy of high MW conjugates increases at physiological temperature. The iron removal from ferritin by HPG-DFO conjugates increases significantly in presence of a low MW chelator, suggesting the potential of combination therapy. The molecular properties of the polymer scaffold also have influence on the prevention of iron mediated oxidation of proteins by the conjugates. The results therefore help to define the iron binding thermodynamics of HPG-DFO and their dependence on MW, and can be extended to improve the general understanding of polymeric chelator-iron interactions in situ.

Improved detection of hereditary haemochromatosis

AIMS

There is high prevalence of hereditary haemochromatosis (HH) in North European populations, yet the diagnosis is often delayed or missed in primary care. Primary care physicians frequently request serum ferritin (SF) estimation but appear uncertain as how to investigate patients with raised SF values. Our aim was to develop a laboratory algorithm with high predictive value for the diagnosis of HH in patients from primary care with raised SF values.

METHODS

Transferrin saturation (Tsat) was measured on SF samples sent from primary care; 1657 male and 2077 female patients age ≥ 30 years with SF ≥ 200 μg/L. HFE genotyping was performed on all 878 male and 867 female patients with Tsat >30%.

RESULTS

This study identified 402 (206 men; 196 women) C282Y carriers and 132 (58 men; 74 women) C282Y homozygotes. Optimal limits for combined SF and Tsat values for HH recognition were established. The detection rate for homozygous C282Y HH for male patients with both SF ≥ 300 μg/L and Tsat >50% was 18.8% (52/272) and 16.3% (68/415) for female patients with both SF ≥ 200 μg/L and Tsat >40%.

CONCLUSIONS

The large number of SF requests received from primary care should be used as a resource to improve the diagnosis of HH in areas of high prevalence.

An assessment of iron overload in children treated for cancer and nonmalignant hematologic disorders

Our goal was to assess the natural fate of iron overload (IO) following transfusions of packed red blood cells (PRBCs) in children treated for cancer and nonmalignant disorders according to the intensity level of their treatment. Sixty-six children were followed up from February 2010 to March 2013. The transfusion burden was compared between three treatment intensity groups assigned according to the Intensity of Treatment Rating Scale 3.0 (ITR-3). IO was assessed by serial measurements of serum ferritin (SF) (n= 66) and quantification of tissue iron by magnetic resonance imaging (MRI) (n=12). Of the children studied, 36 % (24/66) received moderately intensive treatment (level 2), 21 % (14/ 66) received very intensive treatment (level 3), and 42 % (28/ 66) received the most intensive treatment (level 4). The number of PRBC (p=0.016), the total transfused volume (p= 0.026), and transfused volume adjusted to body weight (p= 0.004) were significantly higher in the level 4 group. By the median follow-up time of 35.5 months (range 8–133), 21– 29 % of patients (including level 2 and level 3 children) had SF >1,000 μg/l 1 year after cessation of transfusions. The slowest decrease of SF was observed in the level 4 group. Initial MRI examination demonstrated either mild or moderate IO in the liver and spleen. Repetitive MRI showed significant improvement in relaxation time between the initial and follow-up MRI performances in the liver (5.9 vs. 8.6 ms, p= 0.03) and the spleen (4.3 vs. 8.8 ms, p=0.03).

CONCLUSION

IO diminished over time, but in the level 4 patients, it was detectable for years after cessation of transfusions.

Diagnosis and treatment of hereditary hemochromatosis: an update

Hereditary hemochromatosis is an inherited iron overload disorder caused by inappropriately low hepcidin secretion leading to increased duodenal absorption of dietary iron, most commonly in C282Y homozygous individuals. This can result in elevated serum ferritin, iron deposition in various organs and ultimately end-organ damage, although there is incomplete biochemical and clinical penetrance and variable phenotypic expression of the HFE mutation in hereditary hemochromatosis. An elevated SF >1000 mg/l [corrected] is associated with an increased risk of cirrhosis and mortality in C282Y homozygotes.Conversely, a SF <1000 µg/l is associated with a very low likelihood of cirrhosis, making liver biopsy unnecessary among C282Y homozygotes in the absence of concomitant risk factors for liver disease. Phlebotomy remains the mainstay of treatment and new treatments being studied include erythrocytapheresis and 'mini-hepcidins'. Iron overload is being recognized to play a carcinogenic role in hepatocellular carcinoma and other cancers, possibly supporting iron depletion in these patients.

Hereditary hemochromatosis: laboratory evaluation

The condition of hereditary hemochromatosis (HH) is caused by gene-dependent protein abnormalities involved in iron absorption, storage, or modulation of iron; these abnormalities result in iron overload. The clinical laboratory plays a significant role in case finding, diagnostic validation, and monitoring HH therapy. Elevated serum iron, transferrin saturation, and ferritin suggest HH, but results can also indicate other forms of hepatocyte injury such as alcoholic or viral hepatitis, or other inflammatory disorders involving the liver. In the context of elevated serum iron, transferrin saturation, and ferritin, and after ruling out secondary causes of iron overload, HFE gene evaluation is the preferred test to confirm the diagnosis of HH. However, 5% to 15% of patients with phenotypic HH do not have HFE gene mutations. In these cases, MRI evaluation or liver biopsy with iron quantification is indicated. The clinical role of hepcidin, the iron modulating protein, is undetermined at this time. Because hepcidin also plays a key role in antimicrobial and inflammatory activities, interpretation of hepcidin serum or urine concentration will require thorough understanding of its complex role in iron regulation.

Impact of gene patents and licensing practices on access to genetic testing for hereditary hemochromatosis

Hereditary hemochromatosis is an iron metabolism disorder that leads to excess iron buildup, especially in the heart, liver, and pancreas. Mutations in the HFE gene are the single most common cause of hereditary hemochromatosis, which can be treated effectively if diagnosed early. Patents cover the HFE gene, related proteins, screening methods, and testing kits. Most initial testing for hereditary hemochromatosis is biochemical, but HFE deoxyribonucleic acid testing or genotyping is used to confirm a diagnosis of inherited hemochromatosis. Concerns over patents covering HFE testing emerged in 2002, when scholars argued that exclusive licensing and the patent-enabled sole provider model then in place led to high prices and limited access. Critics of the sole provider model noted that the test was available at multiple laboratories before the enforcement of patents. By 2007, however, Bio-Rad Limited, acquired the key intellectual property and sublicensed it widely. In part because of broad, nonexclusive licensing, there are now multiple providers and testing technologies, and research continues. This case study illustrates how both changes in intellectual property ownership and evolving clinical utility of HFE genetic testing in the last decade have effected the licensing of patents and availability of genetic testing.

Highly sensitivity adhesion molecules detection in hereditary haemochromatosis patients reveals altered expression

Several abnormalities in the immune status of patients with hereditary haemochromatosis (HH) have been reported, suggesting an imbalance in their immune function. This may include persistent production of, or exposure to, altered immune signalling contributing to the pathogenesis of this disorder. Adhesion molecules L-, E- and P-Selectin, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) are some of the major regulators of the immune processes and altered levels of these proteins have been found in pathological states including cardiovascular diseases, arthritis and liver cancer. The aim of this study was to assess L-, E- and P-Selectin, ICAM-1 and VCAM-1 expression in patients with HH and correlate these results with HFE mutation status and iron indexes. A total of 139 subjects were diagnosed with HH (C282Y homozygotes = 87, C282Y/H63D = 26 heterozygotes, H63D homozygotes = 26), 27 healthy control subjects with no HFE mutation (N/N), 18 normal subjects heterozygous for the H63D mutation served as age-sex-matched controls. We observed a significant decrease in L-selectin (P = 0.0002) and increased E-selectin and ICAM-1 (P = 0.0006 and P = 0.0059) expression in HH patients compared with healthy controls. This study observes for the first time that an altered adhesion molecules profile occurs in patients with HH that is associated with specific HFE genetic component for iron overload, suggesting that differential expression of adhesion molecules may play a role in the pathogenesis of HH.

Elevated MCP-1 serum levels are associated with the H63D mutation and not the C282Y mutation in hereditary hemochromatosis

Monocyte chemoattractant protein-1 (MCP-1) is a major lymphocyte and inflammatory chemokine associated with persistent inflammatory states. Several abnormalities in the immune status of patients with hereditary hemochromatosis (HH) have been reported, suggesting an imbalance in their immune function. This may include persistent production of, or exposure to, inflammatory cytokines contributing to the pathogenesis of this disorder. The aim of this study was to assess MCP-1 levels in patients with HH and correlate these results with HFE status and iron indexes. One hundred and thirty-nine subjects diagnosed with HH (C282Y homozygotes = 87, C282Y/H63D = 26 heterozygotes, H63D homozygotes = 26), 27 healthy control subjects with no HFE mutation (N/N), and 18 normal subjects heterozygous for the H63D mutation served as age- and sex-matched controls. Ferritin and transferrin saturation and the presence of HFE mutation status were correlated with MCP-1 levels. Full white blood cell count analysis was also performed. We found a strongly significant decrease in MCP-1 protein levels in the C282Y homozygotes compared with the H63D homozygotes (P = 0.0009) and C282Y/H63D heterozygotes (P = 0.002). Similarly, MCP-1 protein levels in the C282Y homozygotes were decreased compared with the healthy controls (P = 0.00076). Furthermore, MCP-1 serum levels were elevated in H63D patients compared with the healthy controls (P = 0.0008). This study suggests for the first time that a differential expression of MCP-1 protein in patients with HH is associated with the specific HFE genetic component for iron overload. Therefore, these findings offer a possible explanation in the variable clinical spectrum of pathogenesis in patients with HH through abnormalities of an imbalance in the immune states of patients with HH.

Review article: targeted screening for hereditary haemochromatosis in high-risk groups

Patients with hereditary haemochromatosis are at risk for significant morbidity from iron overload as well as reduced life-expectancy once cirrhosis is established. Although inexpensive, sensitive screening tests and effective therapy are available, there is continued debate regarding the utility of screening for this condition because of recent data suggesting that the homozygous haemochromatosis mutation (C282Y) is associated with low penetrance and mild expressivity when identified in population screening studies. In this review, we examine the published data related to general population screening for haemochromatosis, as well as the evidence for screening selected 'high-risk' populations. We also suggest possible screening strategies based on the available evidence.