Iron, hemochromatosis genotypes, and risk of infections: a cohort study of 142 188 general population individuals.

ABSTRACT: It is unclear whether risk of infection is increased in individuals with hereditary hemochromatosis and in individuals with low or high plasma iron, transferrin saturation, or ferritin. Therefore, we tested whether high and low iron, transferrin saturation, and ferritin are associated with risk of infections observationally and genetically through HFE genotypes. We studied 142 188 Danish general population individuals. Iron, transferrin saturation, and ferritin were measured in 136 656, 136 599, and 38 020 individuals, respectively. HFE was genotyped for C282Y and H63D in 132 542 individuals. Median follow-up after study enrollment was 8 years (range, 0-38) for hospital and emergency room admissions with infections (n = 20 394) using the National Patient Register, covering all Danish hospitals. Hazard ratios for any infection were 1.20 (95% confidence interval [CI], 1.12-1.28) and 1.14 (95% CI, 1.07-1.22) in individuals with plasma iron ≤5th or ≥95th percentile compared with individuals with iron from 26th to 74th percentiles. Findings for transferrin saturation were similar, whereas infection risk was not increased in individuals with ferritin ≤5th or ≥95th percentile. Hazard ratios in C282Y homozygotes vs noncarriers were 1.40 (95% CI, 1.16-1.68) for any infection, 1.69 (95% CI, 1.05-2.73) for sepsis, and 2.34 (95% CI, 1.41-3.90) for death from infectious disease. Risk of infection was increased in C282Y homozygotes with normal plasma iron, transferrin saturation, or ferritin, and in C282Y homozygotes without liver disease, diabetes, and/or heart failure. In summary, low and high plasma iron and transferrin saturation were independently associated with increased infection risk. C282Y homozygotes had increased risk of any infection, sepsis, and death from infections. Even C282Y homozygotes with normal iron, transferrin saturation, or ferritin, not currently recommended for genotyping, had increased infection risk.

Targeting PKCα alleviates iron overload in diabetes and hemochromatosis through the inhibition of ferroportin.

ABSTRACT: Ferroportin (Fpn) is the only iron exporter, playing a crucial role in systemic iron homeostasis. Fpn is negatively regulated by its ligand hepcidin, but other potential regulators in physiological and disease conditions remain poorly understood. Diabetes is a metabolic disorder that develops body iron loading with unknown mechanisms. By using diabetic mouse models and human duodenal specimens, we demonstrated that intestinal Fpn expression was increased in diabetes in a hepcidin-independent manner. Protein kinase C (PKC) is hyperactivated in diabetes. We showed that PKCα was required to sustain baseline Fpn expression and diabetes-induced Fpn upregulation in the enterocytes and macrophages. Knockout of PKCα abolished diabetes-associated iron overload. Mechanistically, activation of PKCα increased the exocytotic trafficking of Fpn and decreased the endocytic trafficking of Fpn in the resting state. Hyperactive PKCα also suppressed hepcidin-induced ubiquitination, internalization, and degradation of Fpn. We further observed that iron loading in the enterocytes and macrophages activated PKCα, acting as a novel mechanism to enhance Fpn-dependent iron efflux. Finally, we demonstrated that the loss-of-function of PKCα and pharmacological inhibition of PKC significantly alleviated hereditary hemochromatosis-associated iron overload. Our study has highlighted, to our knowledge, for the first time, that PKCα is an important positive regulator of Fpn and a new target in the control of iron homeostasis.

Structural basis of ferroportin inhibition by minihepcidin PR73.

Ferroportin (Fpn) is the only known iron exporter in humans and is essential for maintaining iron homeostasis. Fpn activity is suppressed by hepcidin, an endogenous peptide hormone, which inhibits iron export and promotes endocytosis of Fpn. Hepcidin deficiency leads to hemochromatosis and iron-loading anemia. Previous studies have shown that small peptides that mimic the first few residues of hepcidin, i.e., minihepcidins, are more potent than hepcidin. However, the mechanism of enhanced inhibition by minihepcidins remains unclear. Here, we report the structure of human ferroportin in complex with a minihepcidin, PR73 that mimics the first 9 residues of hepcidin, at 2.7 Å overall resolution. The structure reveals novel interactions that were not present between Fpn and hepcidin. We validate PR73-Fpn interactions through binding and transport assays. These results provide insights into how minihepcidins increase inhibition potency and will guide future development of Fpn inhibitors.

Hepcidin and Iron in Health and Disease.

Hepcidin, the iron-regulatory hormone, determines plasma iron concentrations and total body iron content. Hepcidin, secreted by hepatocytes, functions by controlling the activity of the cellular iron exporter ferroportin, which delivers iron to plasma from intestinal iron absorption and from iron stores. Hepcidin concentration in plasma is increased by iron loading and inflammation and is suppressed by erythropoietic stimulation and during pregnancy. Hepcidin deficiency causes iron overload in hemochromatosis and anemias with ineffective erythropoiesis. Hepcidin excess causes iron-restrictive anemias including anemia of inflammation. The development of hepcidin diagnostics and therapeutic agonists and antagonists should improve the treatment of iron disorders.

BMP5 contributes to hepcidin regulation and systemic iron homeostasis in mice.

Hepcidin is the master regulator of systemic iron homeostasis. The bone morphogenetic protein (BMP) signaling pathway is a critical regulator of hepcidin expression in response to iron and erythropoietic drive. Although endothelial-derived BMP6 and BMP2 ligands have key functional roles as endogenous hepcidin regulators, both iron and erythropoietic drives still regulate hepcidin in mice lacking either or both ligands. Here, we used mice with an inactivating Bmp5 mutation (Bmp5se), either alone or together with a global or endothelial Bmp6 knockout, to investigate the functional role of BMP5 in hepcidin and systemic iron homeostasis regulation. We showed that Bmp5se-mutant mice exhibit hepcidin deficiency at age 10 days, blunted hepcidin induction in response to oral iron gavage, and mild liver iron loading when fed on a low- or high-iron diet. Loss of 1 or 2 functional Bmp5 alleles also leads to increased iron loading in Bmp6-heterozygous mice and more profound hemochromatosis in global or endothelial Bmp6-knockout mice. Moreover, double Bmp5- and Bmp6-mutant mice fail to induce hepcidin in response to long-term dietary iron loading. Finally, erythroferrone binds directly to BMP5 and inhibits BMP5 induction of hepcidin in vitro. Although erythropoietin suppresses hepcidin in Bmp5se-mutant mice, it fails to suppress hepcidin in double Bmp5- and Bmp6-mutant males. Together, these data demonstrate that BMP5 plays a functional role in hepcidin and iron homeostasis regulation, particularly under conditions in which BMP6 is limited.

Hemochromatosis drives acute lethal intestinal responses to hyperyersiniabactin-producing Yersinia pseudotuberculosis.

Hemachromatosis (iron-overload) increases host susceptibility to siderophilic bacterial infections that cause serious complications, but the underlying mechanisms remain elusive. The present study demonstrates that oral infection with hyperyersiniabactin (Ybt) producing Yersinia pseudotuberculosis Δfur mutant (termed Δfur) results in severe systemic infection and acute mortality to hemochromatotic mice due to rapid disruption of the intestinal barrier. Transcriptome analysis of Δfur-infected intestine revealed up-regulation in cytokine-cytokine receptor interactions, the complement and coagulation cascade, the NF-κB signaling pathway, and chemokine signaling pathways, and down-regulation in cell-adhesion molecules and Toll-like receptor signaling pathways. Further studies indicate that dysregulated interleukin (IL)-1ß signaling triggered in hemachromatotic mice infected with Δfur damages the intestinal barrier by activation of myosin light-chain kinases (MLCK) and excessive neutrophilia. Inhibiting MLCK activity or depleting neutrophil infiltration reduces barrier disruption, largely ameliorates immunopathology, and substantially rescues hemochromatotic mice from lethal Δfur infection. Moreover, early intervention of IL-1ß overproduction can completely rescue hemochromatotic mice from the lethal infection.

Haemochromatosis in children: A national retrospective cohort promoted by the A.I.E.O.P. (Associazione Italiana Emato-Oncologia Pediatrica) study group.

Haemochromatosis (HC) encompasses a range of genetic disorders. HFE-HC is by far the most common in adults, while non-HFE types are rare due to mutations of HJV, HAMP, TFR2 and gain-of-function mutations of SLC40A1. HC is often unknown to paediatricians as it is usually asymptomatic in childhood. We report clinical and biochemical data from 24 paediatric cases of HC (10 cases of HFE-, 5 TFR2-, 9 HJV-HC), with a median follow-up of 9.6 years. Unlike in the adult population, non-HFE-HC constitutes 58% (14/24) of the population in our series. Transferrin saturation was significantly higher in TFR2- and HJV-HC compared to HFE-HC, and serum ferritin and LIC were higher in HJV-HC compared to TFR2- and HFE-HC. Most HFE-HC subjects had relatively low ferritin and LIC at the time of diagnosis, so therapy could be postponed for most of them after the age of 18. Our results confirm that HJV-HC is a severe form already in childhood, emphasizing the importance of early diagnosis and treatment to avoid the development of organ damage and reduce morbidity and mortality. Although phlebotomies were tolerated by most patients, oral iron chelators could be a valid option in early-onset HC.

Haemochromatosis.

Haemochromatosis is one of the most common genetic diseases affecting patients of northern European ancestry. It is overdiagnosed in patients without iron overload and is underdiagnosed in many patients. Early diagnosis by genetic testing and therapy by periodic phlebotomy can prevent the most serious complications, which include liver cirrhosis, liver cancer, and death. This Seminar includes an update on the origins of haemochromatosis; and an overview pathophysiology, genetics, natural history, signs and symptoms, differential diagnoses, treatment with phlebotomy, outcomes, and future directions.

Hemochromatosis classification: update and recommendations by the BIOIRON Society.

Hemochromatosis (HC) is a genetically heterogeneous disorder in which uncontrolled intestinal iron absorption may lead to progressive iron overload (IO) responsible for disabling and life-threatening complications such as arthritis, diabetes, heart failure, hepatic cirrhosis, and hepatocellular carcinoma. The recent advances in the knowledge of pathophysiology and molecular basis of iron metabolism have highlighted that HC is caused by mutations in at least 5 genes, resulting in insufficient hepcidin production or, rarely, resistance to hepcidin action. This has led to an HC classification based on different molecular subtypes, mainly reflecting successive gene discovery. This scheme was difficult to adopt in clinical practice and therefore needs revision. Here we present recommendations for unambiguous HC classification developed by a working group of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society), including both clinicians and basic scientists during a meeting in Heidelberg, Germany. We propose to deemphasize the use of the molecular subtype criteria in favor of a classification addressing both clinical issues and molecular complexity. Ferroportin disease (former type 4a) has been excluded because of its distinct phenotype. The novel classification aims to be of practical help whenever a detailed molecular characterization of HC is not readily available.

Modulation of the HIF2α-NCOA4 axis in enterocytes attenuates iron loading in a mouse model of hemochromatosis.

Intestinal iron absorption is activated during increased systemic demand for iron. The best-studied example is iron deficiency anemia, which increases intestinal iron absorption. Interestingly, the intestinal response to anemia is very similar to that of iron overload disorders, as both the conditions activate a transcriptional program that leads to a hyperabsorption of iron via the transcription factor hypoxia-inducible factor 2α (HIF2α). However, pathways for selective targeting of intestine-mediated iron overload remain unknown. Nuclear receptor coactivator 4 (NCOA4) is a critical cargo receptor for autophagic breakdown of ferritin and the subsequent release of iron, in a process termed ferritinophagy. Our work demonstrates that NCOA4-mediated intestinal ferritinophagy is integrated into systemic iron demand via HIF2α. To demonstrate the importance of the intestinal HIF2α/ferritinophagy axis in systemic iron homeostasis, whole-body and intestine-specific NCOA4-/- mouse lines were generated and assessed. The analyses revealed that the intestinal and systemic response to iron deficiency was not altered after disruption of intestinal NCOA4. However, in a mouse model of hemochromatosis, ablation of intestinal NCOA4 was protective against iron overload. Therefore, NCOA4 can be selectively targeted for the management of iron overload disorders without disrupting the physiological processes involved in the response to systemic iron deficiency.

Differences in bone microarchitecture between genetic and secondary iron-overload mouse models suggest a role for hepcidin deficiency in iron-related osteoporosis.

Iron overload is one of the secondary osteoporosis etiologies. Cellular and molecular mechanisms involved in iron-related osteoporosis are not fully understood. AIM: The aim of the study was to investigate the respective roles of iron excess and hepcidin, the systemic iron regulator, in the development of iron-related osteoporosis. MATERIAL AND METHODS: We used mice models with genetic iron overload (GIO) related to hepcidin deficiency (Hfe-/- and Bmp6-/- ) and secondary iron overload (SIO) exhibiting a hepcidin increase secondary to iron excess. Iron concentration and transferrin saturation levels were evaluated in serum and hepatic, spleen, and bone iron concentrations were assessed by ICP-MS and Perl's staining. Gene expression was evaluated by quantitative RT-PCR. Bone micro-architecture was evaluated by micro-CT. The osteoblastic MC3T3 murine cells that are able to mineralize were exposed to iron and/or hepcidin. RESULTS: Despite an increase of bone iron concentration in all overloaded mice models, bone volume/total volume (BV/TV) and trabecular thickness (Tb.Th) only decreased significantly in GIO, at 12 months for Hfe-/- and from 6 months for Bmp6-/- . Alterations in bone microarchitecture in the Bmp6-/- model were positively correlated with hepcidin levels (BV/TV (ρ = +.481, p < .05) and Tb.Th (ρ = +.690, p < .05). Iron deposits were detected in the bone trabeculae of Hfe-/- and Bmp6-/- mice, while iron deposits were mainly visible in bone marrow macrophages in secondary iron overload. In cell cultures, ferric ammonium citrate exposure abolished the mineralization process for concentrations above 5 µM, with a parallel decrease in osteocalcin, collagen 1, and alkaline phosphatase mRNA levels. Hepcidin supplementation of cells had a rescue effect on the collagen 1 and alkaline phosphatase expression level decrease. CONCLUSION: Together, these data suggest that iron in excess alone is not sufficient to induce osteoporosis and that low hepcidin levels also contribute to the development of osteoporosis.

Hereditary hemochromatosis with homozygous C282Y HFE mutation: possible clinical model to assess effects of elevated reactive oxygen species on the development of cardiovascular disease.

Hereditary hemochromatosis with the homozygous C282Y HFE mutation (HH-282H) is a genetic condition which causes iron overload (IO) and elevated reactive oxygen species (ROS) secondary to the IO. Interestingly, even after successful iron removal therapy, HH-282H subjects demonstrate chronically elevated ROS. Raised ROS are also associated with the development of multiple cardiovascular diseases and HH-282H subjects may be at risk to develop these complications. In this narrative review, we consider HH-282H subjects as a clinical model for assessing the contribution of elevated ROS to the development of cardiovascular diseases in subjects with fewer confounding clinical risk factors as compared to other disease conditions with high ROS. We identify HH-282H subjects as a potentially unique clinical model to assess the impact of chronically elevated ROS on the development of cardiovascular disease and to serve as a clinical model to detect effective interventions for anti-ROS therapy.

Associations between metabolic hyperferritinaemia, fibrosis-promoting alleles and clinical outcomes in steatotic liver disease.

BACKGROUND & AIMS: Ferritin has been investigated as a biomarker for liver fibrosis and iron in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). However, whether metabolic hyperferritinaemia predicts progression of liver disease remains unknown. In this study, we sought to understand associations between hyperferritinaemia and (1) adverse clinical outcomes and (2) common genetic variants related to iron metabolism and liver fibrosis. METHODS: This was a retrospective analysis of adults with MASLD seen at the University of Michigan Health System, where MASLD was defined by hepatic steatosis on imaging, biopsy or vibration-controlled transient elastography, plus metabolic risk factors in the absence of chronic liver diseases other than hemochromatosis. The primary predictor was serum ferritin level, which was dichotomized based on a cut-off of 300 or 450 mcg/L for women or men. Primary outcomes included (1) incident cirrhosis, liver-related events, congestive heart failure (CHF), and mortality and (2) distribution of common genetic variants associated with hepatic fibrosis and hereditary hemochromatosis. RESULTS: Of 7333 patients with MASLD, 1468 (20%) had elevated ferritin. In multivariate analysis, ferritinaemia was associated with increased mortality (HR 1.68 [1.35-2.09], p < .001) and incident liver-related events (HR 1.92 [1.11-3.32], p = .019). Furthermore, elevated ferritin was associated with carriage of cirrhosis-promoting alleles including PNPLA3-rs738409-G allele (p = .0068) and TM6SF2-rs58542926-T allele (p = 0.0083) but not with common HFE mutations. CONCLUSIONS: In MASLD patients, metabolic hyperferritinaemia was associated with increased mortality and higher incidence of liver-related events, and cirrhosis-promoting alleles but not with iron overload-promoting HFE mutations.

Penetrance, cancer incidence and survival in HFE haemochromatosis-A population-based cohort study.

BACKGROUND AND AIMS: Haemochromatosis is characterized by progressive iron overload affecting the liver and can cause cirrhosis and hepatocellular carcinoma. Most haemochromatosis patients are homozygous for p.C282Y in HFE, but only a minority of individuals with this genotype will develop the disease. The aim was to assess the penetrance of iron overload, fibrosis, hepatocellular carcinoma and life expectancy. METHODS: A total of 8839 individuals from the Austrian region of Tyrol were genotyped for the p.C282Y variant between 1997 and 2021. Demographic, laboratory parameters and causes of death were assessed from health records. Penetrance, survival, and cancer incidence were ascertained from diagnosed cases, insurance- and cancer registry data. Outcomes were compared with a propensity score-matched control population. RESULTS: Median age at diagnosis in 542 p.C282Y homozygous individuals was 47.8 years (64% male). At genotyping, the prevalence of iron overload was 55%. The cumulative penetrance of haemochromatosis defined as the presence of provisional iron overload was 24.2% in males and 10.5% in females aged 60 years or younger. Among p.C282Y homozygotes of the same ages, the cumulative proportion of individuals without fibrosis (FIB-4 score < 1.3) was 92.8% in males and 96.7% in females. Median life expectancy was reduced by 6.8 years in individuals homozygous for p.C282Y when compared with population-matched controls (p = .001). Hepatocellular carcinoma incidence was not significantly higher in p.C282Y homozygotes than in controls matched for age and sex. CONCLUSION: Reduced survival and the observed age-dependent increase in penetrance among p.C282Y homozygotes call for earlier diagnosis of haemochromatosis to prevent complications.

SUGP2 p.(Arg639Gln) variant is involved in the pathogenesis of hemochromatosis via the CIRBP/BMPER signaling pathway.

Pathogenic variants in HFE and non-HFE genes have been identified in hemochromatosis in different patient populations, but there are still a certain number of patients with unexplained primary iron overload. We recently identified in Chinese patients a recurrent p.(Arg639Gln) variant in SURP and G-patch domain containing 2 (SUGP2), a potential mRNA splicing-related factor. However, the target gene of SUGP2 and affected iron-regulating pathway remains unknown. We aimed to investigate the pathogenicity and underlying mechanism of this variant in hemochromatosis. RNA-seq analysis revealed that SUGP2 knockdown caused abnormal alternative splicing of CIRBP pre-mRNA, resulting in an increased normal splicing form of CIRBP V1, which in turn increased the expression of BMPER by enhancing its mRNA stability and translation. Furthermore, RNA-protein pull-down and RNA immunoprecipitation assays revealed that SUGP2 inhibited splicing of CIRBP pre-mRNA by a splice site variant at CIRBP c.492 and was more susceptible to CIRBP c.492 C/C genotype. Cells transfected with SUGP2 p.(Arg639Gln) vector showed up-regulation of CIRBP V1 and BMPER expression and down-regulation of pSMAD1/5 and HAMP expression. CRISPR-Cas9 mediated SUGP2 p.(Arg622Gln) knock-in mice showed increased iron accumulation in the liver, higher total serum iron, and decreased serum hepcidin level. A total of 10 of 54 patients with hemochromatosis (18.5%) harbored the SUGP2 p.(Arg639Gln) variant and carried CIRBP c.492 C/C genotype, and had increased BMPER expression in the liver. Altogether, the SUGP2 p.(Arg639Gln) variant down-regulates hepcidin expression through the SUGP2/CIRBP/BMPER axis, which may represent a novel pathogenic factor for hemochromatosis.

Iron overload disorders: Growth and gonadal dysfunction in childhood and adolescence.

Hemochromatosis (HC) is characterized by the progressive accumulation of iron in the body, resulting in organ damage. Endocrine complications are particularly common, especially when the condition manifests in childhood or adolescence, when HC can adversely affect linear growth or pubertal development, with significant repercussions on quality of life even into adulthood. Therefore, a timely and accurate diagnosis of these disorders is mandatory, but sometimes complex for hematologists without endocrinological support. This is a narrative review focused on puberty and growth disorders during infancy and adolescence aiming to offer guidance for diagnosis, treatment, and proper follow-up. Additionally, it aims to highlight gaps in the existing literature and emphasizes the importance of collaboration among specialists, which is essential in the era of precision medicine.

Edwardsiella piscicida causes iron storage disorders by an autophagy pathway in fish monocytes/macrophages.

Edwardsiella piscicida (E. piscicida) is a gram-negative pathogen that survives in intracellular environment. Currently, the interplay between E. piscicida and host cells has not been completely explored. In this study, we found that E. piscicida disturbed iron homeostasis in grass carp monocytes/macrophages to maintain its own growth. Further investigation revealed the bacteria induced an increase of intracellular iron, which was subjected to the degradation of ferritin. Moreover, the autophagy inhibitor impeded the degradation of ferritin and increase of intracellular iron in E. piscicida-infected monocytes/macrophages, implying possible involvement of autophagy response in the process of E. piscicida-broken iron homeostasis. Along this line, confocal microscopy observed that E. piscicida elicited the colocalization of ferritin with LC3-positive autophagosome in the monocytes/macrophages, indicating that E. piscicida mediated the degradation of ferritin possibly through the autophagic pathway. These results deepened our understanding of the interaction between E. piscicida and fish cells, hinting that the disruption of iron homeostasis was an important factor for pathogenicity of E. piscicida. They also indicated that autophagy was a possible mechanism governing intracellular iron metabolism in response to E. piscicida infection and might offer a new avenue for anti-E. piscicida strategies in the future.

Eicosanoids and Oxylipin Signature in Hereditary Hemochromatosis Patients Are Similar to Dysmetabolic Iron Overload Syndrome Patients but Are Impacted by Dietary Iron Absorption.

INTRODUCTION: Oxylipins are mediators of oxidative stress. To characterize the underlying inflammatory processes and phenotype effect of iron metabolism disorders, we investigated the oxylipin profile in hereditary hemochromatosis (HH) and dysmetabolic iron overload syndrome (DIOS) patients. METHODS: An LC-MS/MS-based method was performed to quantify plasma oxylipins in 20 HH and 20 DIOS patients in fasting conditions and 3 h after an iron-rich meal in HH patients. RESULTS: Principal component analysis showed no separation between HH and DIOS, suggesting that the clinical phenotype has no direct impact on oxylipin metabolism. 20-HETE was higher in DIOS and correlated with hypertension (p = 0.03). Different oxylipin signatures were observed in HH before and after the iron-rich meal. Discriminant oxylipins include epoxy fatty acids derived from docosahexaenoic acid and arachidonic acid as well as 13-HODE and 9-HODE. Mediation analysis found no major contribution of dietary iron absorption for 16/22 oxylipins significantly affected by the meal. DISCUSSION: The oxylipin profiles of HH and DIOS seemed similar except for 20-HETE, possibly reflecting different hypertension prevalence between the two groups. Oxylipins were significantly affected by the iron-rich meal, but the specific contribution of iron was not clear. Although iron may contribute to oxidative stress and inflammation in HH and DIOS, this does not seem to directly affect oxylipin metabolism.

The relationship between liver stiffness by two-dimensional shear wave elastography and iron overload status in transfusion-dependent patients.

Increased liver stiffness (LS) can be result of increased liver iron concentration (LIC) which may not yet be reflected in the liver fibrotic status. The objective of our study was to examine relationship between hemochromatosis, LS, and serum ferritin level in transfusion-dependent patients. We recruited all 70 transfusion-dependent patients, whose median age was 15, referred for evaluating LIC status by magnetic resonance imaging (MRI) followed by two-dimensional ultrasonography shear wave elastography (2D-SWE). Thalassemia beta affected the majority of the patients. The optimal cut point for prediction of severe hemochromatosis using median SWE (kPa) and SWV (m/s) was ≥ 7.0 kPa and ≥ 1.54 m/s, respectively, with sensitivity of 0.76 (95% confidence interval [CI] 0.55, 0.91) and, specificity of 0.69 (95%CI 0.53, 0.82). When combing the optimal cut point of SWE (kPa) at ≥ 7.0 and serum ferritin ≥ 4123 ng/mL, the sensitivity increased to 0.84 (95%CI 0.64, 0.95) with specificity of 0.67 (95%CI 0.50, 0.80), positive predictive value (PPV) of 0.60 (95%CI 0.42, 0.76), and negative predictive value (NPV) of 0.88 (95%CI 0.71, 0.96). Simultaneous tests of 2D-SWE and serum ferritin for prediction of severe hemochromatosis showed the highest sensitivity of 84% (95%CI 0.64-0.95), as compared to 2D-SWE alone at 76% (95%CI 0.55, 0.91) or serum ferritin alone at 44% (95%CI 0.24-0.65). We recommend measuring both 2D-SWE and serum ferritin in short interval follow up patients. Adding 2D-SWE to management guideline will help in deciding for aggressive adjustment of iron chelating medication and increased awareness of patients having severe hemochromatosis.

Hemochromatosis: Ferroptosis, ROS, Gut Microbiome, and Clinical Challenges with Alcohol as Confounding Variable.

Hemochromatosis represents clinically one of the most important genetic storage diseases of the liver caused by iron overload, which is to be differentiated from hepatic iron overload due to excessive iron release from erythrocytes in patients with genetic hemolytic disorders. This disorder is under recent mechanistic discussion regarding ferroptosis, reactive oxygen species (ROS), the gut microbiome, and alcohol abuse as a risk factor, which are all topics of this review article. Triggered by released intracellular free iron from ferritin via the autophagic process of ferritinophagy, ferroptosis is involved in hemochromatosis as a specific form of iron-dependent regulated cell death. This develops in the course of mitochondrial injury associated with additional iron accumulation, followed by excessive production of ROS and lipid peroxidation. A low fecal iron content during therapeutic iron depletion reduces colonic inflammation and oxidative stress. In clinical terms, iron is an essential trace element required for human health. Humans cannot synthesize iron and must take it up from iron-containing foods and beverages. Under physiological conditions, healthy individuals allow for iron homeostasis by restricting the extent of intestinal iron depending on realistic demand, avoiding uptake of iron in excess. For this condition, the human body has no chance to adequately compensate through removal. In patients with hemochromatosis, the molecular finetuning of intestinal iron uptake is set off due to mutations in the high-FE2+ (HFE) genes that lead to a lack of hepcidin or resistance on the part of ferroportin to hepcidin binding. This is the major mechanism for the increased iron stores in the body. Hepcidin is a liver-derived peptide, which impairs the release of iron from enterocytes and macrophages by interacting with ferroportin. As a result, iron accumulates in various organs including the liver, which is severely injured and causes the clinically important hemochromatosis. This diagnosis is difficult to establish due to uncharacteristic features. Among these are asthenia, joint pain, arthritis, chondrocalcinosis, diabetes mellitus, hypopituitarism, hypogonadotropic hypogonadism, and cardiopathy. Diagnosis is initially suspected by increased serum levels of ferritin, a non-specific parameter also elevated in inflammatory diseases that must be excluded to be on the safer diagnostic side. Diagnosis is facilitated if ferritin is combined with elevated fasting transferrin saturation, genetic testing, and family screening. Various diagnostic attempts were published as algorithms. However, none of these were based on evidence or quantitative results derived from scored key features as opposed to other known complex diseases. Among these are autoimmune hepatitis (AIH) or drug-induced liver injury (DILI). For both diseases, the scored diagnostic algorithms are used in line with artificial intelligence (AI) principles to ascertain the diagnosis. The first-line therapy of hemochromatosis involves regular and life-long phlebotomy to remove iron from the blood, which improves the prognosis and may prevent the development of end-stage liver disease such as cirrhosis and hepatocellular carcinoma. Liver transplantation is rarely performed, confined to acute liver failure. In conclusion, ferroptosis, ROS, the gut microbiome, and concomitant alcohol abuse play a major contributing role in the development and clinical course of genetic hemochromatosis, which requires early diagnosis and therapy initiation through phlebotomy as a first-line treatment.