Role of albumin infusion in cirrhosis-associated complications.

Cirrhosis is an advanced-stage liver disease that occurs due to persistent physiological insults such as excessive alcohol consumption, infections, or toxicity. It is characterised by scar tissue formation, portal hypertension, and ascites (accumulation of fluid in the abdominal cavity) in decompensated cirrhosis. This review evaluates how albumin infusion ameliorates cirrhosis-associated complications. Since albumin is an oncotic plasma protein, albumin infusion allows movement of water into the intravascular space, aids with fluid resuscitation, and thereby contributes to resolving cirrhosis-induced hypovolemia (loss of extracellular fluid) seen in ascites. Thus, albumin infusion helps prevent paracentesis-induced circulatory dysfunction, a complication that occurs when treating ascites. When cirrhosis advances, other complications such as spontaneous bacterial peritonitis and hepatorenal syndrome can manifest. Infused albumin helps mitigate these by exhibiting plasma expansion, antioxidant, and anti-inflammatory functions. In hepatic encephalopathy, albumin infusion is thought to improve cognitive function by reducing ammonia concentration in blood and thereby tackle cirrhosis-induced hepatocyte malfunction in ammonia clearance. Infused albumin can also exhibit protective effects by binding to the cirrhosis-induced proinflammatory cytokines TNFα and IL6. While albumin administration has shown to prolong overall survival of cirrhotic patients with ascites in the ANSWER trial, the ATTIRE and MACHT trials have shown either no effect or limitations such as development of pulmonary oedema and multiorgan failure.  Thus, albumin infusion is not a generic treatment option for all cirrhosis patients. Interestingly, cirrhosis-induced structural alterations in native albumin (which lead to formation of different albumin isoforms) can be used as prognostic biomarkers because specific albumin isoforms indicate certain complications of decompensated cirrhosis.

Role of zinc in health and disease.

This review provides a concise overview of the cellular and clinical aspects of the role of zinc, an essential micronutrient, in human physiology and discusses zinc-related pathological states. Zinc cannot be stored in significant amounts, so regular dietary intake is essential. ZIP4 and/or ZnT5B transport dietary zinc ions from the duodenum into the enterocyte, ZnT1 transports zinc ions from the enterocyte into the circulation, and ZnT5B (bidirectional zinc transporter) facilitates endogenous zinc secretion into the intestinal lumen. Putative promoters of zinc absorption that increase its bioavailability include amino acids released from protein digestion and citrate, whereas dietary phytates, casein and calcium can reduce zinc bioavailability. In circulation, 70% of zinc is bound to albumin, and the majority in the body is found in skeletal muscle and bone. Zinc excretion is via faeces (predominantly), urine, sweat, menstrual flow and semen. Excessive zinc intake can inhibit the absorption of copper and iron, leading to copper deficiency and anaemia, respectively. Zinc toxicity can adversely affect the lipid profile and immune system, and its treatment depends on the mode of zinc acquisition. Acquired zinc deficiency usually presents later in life alongside risk factors like malabsorption syndromes, but medications like diuretics and angiotensin-receptor blockers can also cause zinc deficiency. Inherited zinc deficiency condition acrodermatitis enteropathica, which occurs due to mutation in the SLC39A4 gene (encoding ZIP4), presents from birth. Treatment involves zinc supplementation via zinc gluconate, zinc sulphate or zinc chloride. Notably, oral zinc supplementation may decrease the absorption of drugs like ciprofloxacin, doxycycline and risedronate.

Iron-Related Genes and Proteins in Mesenchymal Stem Cell Detection and Therapy.

Mesenchymal stem cells (MSCs) are located in various tissues of the body. These cells exhibit regenerative and reparative properties, which makes them highly valuable for cell-based therapy. Despite this, majority of MSC-related studies remain to be translated for regular clinical use. This is partly because there are methodical challenges in pre-administration MSC labelling, post-administration detection and tracking of cells, and in retention of maximal therapeutic potential in-vivo. This calls for exploration of alternative or adjunctive approaches that would enable better detection of transplanted MSCs via non-invasive methods and enhance MSC therapeutic potential in-vivo. Interestingly, these attributes have been demonstrated by some iron-related genes and proteins.Accordingly, this unique forward-looking article integrates the apparently distinct fields of iron metabolism and MSC biology, and reviews the utility of iron-related genes and iron-related proteins in facilitating MSC detection and therapy, respectively. Effects of genetic overexpression of the iron-related proteins ferritin, transferrin receptor-1 and MagA in MSCs and their utilisation as reporter genes for improving MSC detection in-vivo are critically evaluated. In addition, the beneficial effects of the iron chelator deferoxamine and the iron-related proteins haem oxygenase-1, lipocalin-2, lactoferrin, bone morphogenetic protein-2 and hepcidin in enhancing MSC therapeutics are highlighted with the consequent intracellular alterations in MSCs. This review aims to inform both regenerative and translational medicine. It can aid in formulating better methodical approaches that will improve, complement, or provide alternatives to the current pre-transplantation MSC labelling procedures, and enhance MSC detection or augment the post-transplantation MSC therapeutic potential.

Liver biopsy for assessment of chronic liver diseases: a synopsis.

The world-wide increase in chronic liver disease (CLD) calls for refinement of diagnostic and prognostic measures for early and accurate disease detection and management. Regardless of the aetiology, liver biopsy allows direct visualisation of specimen under the microscope. It facilitates histological evaluation of disease-specific morphological alterations. Thereby, it aids in disease diagnosis, prognosis, and assessment of treatment compliance/response. Indeed, with the advent of non-invasive methods, liver biopsy is used less frequently than before, but it is still considered as a gold standard for staging and grading several CLDs. This short review revisits liver biopsy. It highlights the significance of liver biopsy in evaluating CLDs and explains the commonly used Ishak, METAVIR and Batts-Ludwig scoring systems for grading and staging CLDs. The utility of liver biopsy in examining alcohol-related liver disease and non-alcoholic fatty liver disease (NAFLD) is discussed along with the disease-specific alcoholic hepatitis histology score (AHHS) and non-alcoholic fatty liver disease activity score (NAS). Additionally, the review elaborates on the role of liver biopsy in evaluating viral hepatitis, haemochromatosis, and hepatocellular carcinoma. Contextual explanation on the diagnosis of metabolic dysfunction-associated liver disease (MAFLD) is provided. The significance and clinical indications of repeat biopsy are also explained. Lastly, caveats and limitations associated with liver biopsy are reviewed. Essentially, this review collates the application of liver biopsy in assessing various CLDs and provides succinct explanations of the core scoring systems, all under one roof. It is clinically relevant and provides a useful synopsis to budding scientists and hepato-pathologists.

Iron and iron-related proteins in COVID-19.

COVID-19 can cause detrimental effects on health. Vaccines have helped in reducing disease severity and transmission but their long-term effects on health and effectiveness against future viral variants remain unknown. COVID-19 pathogenesis involves alteration in iron homeostasis. Thus, a contextual understanding of iron-related parameters would be very valuable for disease prognosis and therapeutics.Accordingly, we reviewed the status of iron and iron-related proteins in COVID-19. Iron-associated alterations in COVID-19 reported hitherto include anemia of inflammation, low levels of serum iron (hypoferremia), transferrin and transferrin saturation, and high levels of serum ferritin (hyperferritinemia), hepcidin, lipocalin-2, catalytic iron, and soluble transferrin receptor (in ICU patients). Hemoglobin levels can be low or normal, and compromised hemoglobin function has been proposed. Membrane-bound transferrin receptor may facilitate viral entry, so it acts as a potential target for antiviral therapy. Lactoferrin can provide natural defense by preventing viral entry and/or inhibiting viral replication. Serum iron and ferritin levels can predict COVID-19-related hospitalization, severity, and mortality. Serum hepcidin and ferritin/transferrin ratio can predict COVID-19 severity. Here, serum levels of these iron-related parameters are provided, caveats of iron chelation for therapy are discussed and the interplay of these iron-related parameters in COVID-19 is explained.This synopsis is crucial as it clearly presents the iron picture of COVID-19. The information may assist in disease prognosis and/or in formulating iron-related adjunctive strategies that can help reduce infection/inflammation and better manage COVID-19 caused by future variants. Indeed, the current picture will augment as more is revealed about these iron-related parameters in COVID-19.

Liver Iron Loading in Alcohol-Associated Liver Disease.

Alcohol-associated liver disease (ALD) is a common chronic liver disease with increasing incidence worldwide. Alcoholic liver steatosis/steatohepatitis can progress to liver fibrosis/cirrhosis, which can cause predisposition to hepatocellular carcinoma. ALD diagnosis and management are confounded by several challenges. Iron loading is a feature of ALD which can exacerbate alcohol-induced liver injury and promote ALD pathologic progression. Knowledge of the mechanisms that mediate liver iron loading can help identify cellular/molecular targets and thereby aid in designing adjunct diagnostic, prognostic, and therapeutic approaches for ALD. Herein, the cellular mechanisms underlying alcohol-induced liver iron loading are reviewed and how excess iron in patients with ALD can promote liver fibrosis and aggravate disease pathology is discussed. Alcohol-induced increase in hepatic transferrin receptor-1 expression and up-regulation of high iron protein in Kupffer cells (proposed) facilitate iron deposition and retention in the liver. Iron is loaded in both parenchymal and nonparenchymal liver cells. Iron-loaded liver can promote ferroptosis and thereby contribute to ALD pathology. Iron and alcohol can independently elevate oxidative stress. Therefore, a combination of excess iron and alcohol amplifies oxidative stress and accelerates liver injury. Excess iron-stimulated hepatocytes directly or indirectly (through Kupffer cell activation) activate the hepatic stellate cells via secretion of proinflammatory and profibrotic factors. Persistently activated hepatic stellate cells promote liver fibrosis, and thereby facilitate ALD progression.

Iron and iron-related proteins in alcohol consumers: cellular and clinical aspects.

Alcohol-associated liver disease (ALD) is one of the most common chronic liver diseases. Its pathological spectrum includes the overlapping stages of hepatic steatosis/steatohepatitis that can progress to liver fibrosis and cirrhosis; both are risk factors for hepatocellular carcinoma. Moreover, ALD diagnosis and management pose several challenges. The early pathological stages are reversible by alcohol abstinence, but these early stages are often asymptomatic, and currently, there is no specific laboratory biomarker or diagnostic test that can confirm ALD etiology. Alcohol consumers frequently show dysregulation of iron and iron-related proteins. Examination of iron-related parameters in this group may aid in early disease diagnosis and better prognosis and management. For this, a coherent overview of the status of iron and iron-related proteins in alcohol consumers is essential. Therefore, here, we collated and reviewed the alcohol-induced alterations in iron and iron-related proteins. Reported observations include unaltered, increased, or decreased levels of hemoglobin and serum iron, increments in intestinal iron absorption (facilitated via upregulations of duodenal divalent metal transporter-1 and ferroportin), serum ferritin and carbohydrate-deficient transferrin, decrements in serum hepcidin, decreased or unaltered levels of transferrin, increased or unaltered levels of transferrin saturation, and unaltered levels of soluble transferrin receptor. Laboratory values of iron and iron-related proteins in alcohol consumers are provided for reference. The causes and mechanisms underlying these alcohol-induced alterations in iron parameters and anemia in ALD are explained. Notably, alcohol consumption by hemochromatosis (iron overload) patients worsens disease severity due to the synergistic effects of excess iron and alcohol.

Hepcidin in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common reasons for cancer-related deaths. Excess iron increases HCC risk. Inevitably, hepcidin, the iron hormone that maintains systemic iron homoeostasis is involved in HCC pathology. Distinct from other cancers that show high hepcidin expression, HCC patients can show low hepcidin levels. Thus, it is of immense clinical benefit to address the regulation and action of hepcidin in HCC as this may help in identifying molecular targets for diagnosis, prognosis, and therapeutics. Accordingly, this review explores hepcidin in HCC. It presents the levels of tissue and serum hepcidin and explains the mechanisms that contribute to hepcidin reduction in HCC. These include downregulation of HAMP, TfR2, HJV, ALK2 and circular RNA circ_0004913, upregulation of matriptase-2 and GDF15, inactivation of RUNX3 and mutation in TP53. The enigmas around mir-122 and the functionalities of two major hepcidin inducers BMP6 and IL6 in relation to hepcidin in HCC are discussed. Effects of hepcidin downregulation are explained, specifically, increased cancer proliferation via activation of CDK1/STAT3 pathway and increased HCC risk due to reduction in a hepcidin-mediated protective effect against hepatic stellate cell activation. Hepcidin-ferroportin axis in HCC is addressed. Finally, the role of hepcidin in the diagnosis, prognosis and therapeutics of HCC is highlighted.

Iron Oxide Nanoparticles in Mesenchymal Stem Cell Detection and Therapy.

Mesenchymal stem cells (MSCs) exhibit regenerative and reparative properties. However, most MSC-related studies remain to be translated for regular clinical usage, partly due to challenges in pre-transplantation cell labelling and post-transplantation cell tracking. Amidst this, there are growing concerns over the toxicity of commonly used gadolinium-based contrast agents that mediate in-vivo cell detection via MRI. This urges to search for equally effective but less toxic alternatives that would facilitate and enhance MSC detection post-administration and provide therapeutic benefits in-vivo. MSCs labelled with iron oxide nanoparticles (IONPs) have shown promising results in-vitro and in-vivo. Thus, it would be useful to revisit these studies before inventing new labelling approaches. Aiming to inform regenerative medicine and augment clinical applications of IONP-labelled MSCs, this review collates and critically evaluates the utility of IONPs in enhancing MSC detection and therapeutics. It explains the rationale, principle, and advantages of labelling MSCs with IONPs, and describes IONP-induced intracellular alterations and consequent cellular manifestations. By exemplifying clinical pathologies, it examines contextual in-vitro, animal, and clinical studies that used IONP-labelled bone marrow-, umbilical cord-, adipose tissue- and dental pulp-derived MSCs. It compiles and discusses studies involving MSC-labelling of IONPs in combinations with carbohydrates (Venofer, ferumoxytol, dextran, glucosamine), non-carbohydrate polymers [poly(L-lysine), poly(lactide-co-glycolide), poly(L-lactide), polydopamine], elements (ruthenium, selenium, gold, zinc), compounds/stains (silica, polyethylene glycol, fluorophore, rhodamine B, DAPI, Prussian blue), DNA, Fibroblast growth Factor-2 and the drug doxorubicin. Furthermore, IONP-labelling of MSC exosomes is reviewed. Also, limitations of IONP-labelling are addressed and methods of tackling those challenges are suggested.

Betaine in ameliorating alcohol-induced hepatic steatosis.

Alcohol-associated liver disease (AALD) is one of most common chronic liver diseases. Hepatic steatosis is the earliest stage in AALD pathological spectrum, reversible by alcohol abstinence. Untreated steatosis can progress to steatohepatitis, fibrosis and/or cirrhosis. Considering the difficulties in achieving complete abstinence, challenges in disease reversal at advanced stages, high costs of AALD management and lack of standardised prescribed medications for treatment, it is essential to explore low-cost natural compounds that can target AALD at an early stage and halt or decelerate disease progression. Betaine is a non-hazardous naturally occurring nutrient. Here, we address the mechanisms of alcohol-induced hepatic steatosis, the role of betaine in reversing the effects i.e., its action against hepatic steatosis in animal models and humans, and the associated cellular and molecular processes. Accordingly, the review discusses how betaine restores the alcohol-induced reduction in methylation potential by elevating the levels of S-adenosylmethionine and methionine. It details how betaine reinstates alcohol-induced alterations in the expressions and/or activities of protein phosphtase-2A, FOXO1, PPAR-α, AMPK, SREBP-1c, fatty acid synthase, diacylglycerol transferase-2, adiponectin and nitric oxide. Interrelationships between these factors in preventing de novo lipogenesis, reducing hepatic uptake of adipose-tissue-derived free fatty acids, promoting VLDL synthesis and secretion, and restoring ß-oxidation of fatty acids to attenuate hepatic triglyceride accumulation are elaborated. Despite its therapeutic potential, very few clinical trials have examined betaine's effect on alcohol-induced hepatic lipid accumulation. This review will provide further confidence to conduct randomised control trials to enable maximum utilisation of betaine's remedial properties to treat alcohol-induced hepatic steatosis.

Role of iron and iron-related proteins in mesenchymal stem cells: Cellular and clinical aspects.

Mesenchymal stem cells (MSCs) are located in various tissues where these cells show niche-dependent multilineage differentiation and secrete immunomodulatory molecules to support numerous physiological processes. Due to their regenerative and reparative properties, MSCs are extremely valuable for cell-based therapy in tackling several pathological conditions including COVID-19. Iron is essential for MSC processes but iron-loading, which is common in several chronic conditions, hinders normal MSC functionality. This not only aggravates disease pathology but can also affect allogeneic and autologous MSC therapy. Thus, understanding MSCs from an iron perspective is of clinical significance. Accordingly, this review highlights the roles of iron and iron-related proteins in MSC physiology. It describes the contribution of iron and endogenous iron-related effectors like hepcidin, ferroportin, transferrin receptor, lactoferrin, lipocalin-2, bone morphogenetic proteins and hypoxia inducible factors in MSC biology. It summarises the excess-iron-induced alterations in MSC components, processes and discusses signalling pathways involving ROS, PI3K/AKT, MAPK, p53, AMPK/MFF/DRP1 and Wnt. Additionally, it evaluates the endogenous and exogenous saviours of MSCs against iron-toxicity. Lastly, it elaborates on the involvement of MSCs in the pathology of clinical conditions of iron-excess, namely, hereditary hemochromatosis, diabetes, ß-thalassaemia and myelodysplastic syndromes. This unique review integrates the distinct fields of iron regulation and MSC physiology. Through an iron-perspective, it describes both mechanistic and clinical aspects of MSCs and proposes an iron-linked MSC-contribution to physiology, pathology and therapeutics. It advances the understanding of MSC biology and may aid in identifying signalling pathways, molecular targets and compounds for formulating adjunctive iron-based therapies for excess-iron conditions, and thereby inform regenerative medicine.

Iron elevates mesenchymal and metastatic biomarkers in HepG2 cells.

Liver iron excess is observed in several chronic liver diseases and is associated with the development of hepatocellular carcinoma (HCC). However, apart from oxidative stress, other cellular mechanisms by which excess iron may mediate/increase HCC predisposition/progression are not known. HCC pathology involves epithelial to mesenchymal transition (EMT), the basis of cancer phenotype acquisition. Here, the effect of excess iron (holo-transferrin 0-2 g/L for 24 and 48 h) on EMT biomarkers in the liver-derived HepG2 cells was investigated. Holo-transferrin substantially increased intracellular iron. Unexpectedly, mRNA and protein expression of the epithelial marker E-cadherin either remained unaltered or increased. The mRNA and protein levels of metastasis marker N-cadherin and mesenchymal marker vimentin increased significantly. While the mRNA expression of EMT transcription factors SNAI1 and SNAI2 increased and decreased, respectively after 24 h, both factors increased after 48 h. The mRNA expression of TGF-ß (EMT-inducer) showed no significant alterations. In conclusion, data showed direct link between iron and EMT. Iron elevated mesenchymal and metastatic biomarkers in HepG2 cells without concomitant decrement in the epithelial marker E-cadherin and altered the expression of the key EMT-mediating transcription factors. Such studies can help identify molecular targets to devise iron-related adjunctive therapies to ameliorate HCC pathophysiology.

High omega arachidonic acid/docosahexaenoic acid ratio induces mitochondrial dysfunction and altered lipid metabolism in human hepatoma cells.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a common cause of liver disease worldwide and is a growing epidemic. A high ratio of omega-6 fatty acids to omega-3 fatty acids in the diet has been implicated in the development of NAFLD. However, the inflicted cellular pathology remains unknown. A high ratio may promote lipogenic pathways and contribute to reactive oxygen species (ROS)-mediated damage, perhaps leading to mitochondrial dysfunction. Therefore, these parameters were investigated to understand their contribution to NAFLD development. AIM: To examine the effect of increasing ratios of omega-6:3 fatty acids on mitochondrial function and lipid metabolism mediators. METHODS: HepG2-derived VL-17A cells were treated with normal (1:1, 4:1) and high (15:1, 25:1) ratios of omega-6: omega-3 fatty acids [arachidonic acid (AA): docosahexaenoic acid (DHA)] at various time points. Mitochondrial activity and function were examined via MTT assay and Seahorse XF24 analyzer, respectively. Triglyceride accumulation was determined by using EnzyChrom™ and levels of ROS were measured by fluorescence intensity. Protein expression of the mediators of lipogenic, lipolytic and endocannabinoid pathways was assessed by Western blotting. RESULTS: High AA:DHA ratio decreased mitochondrial activity (P < 0.01; up to 80%) and promoted intracellular triglyceride accumulation (P < 0.05; 40%-70%). Mechanistically, it altered the mediators of lipid metabolism; increased the expression of stearoyl-CoA desaturase (P < 0.05; 22%-35%), decreased the expression of peroxisome proliferator-activated receptor-alpha (P < 0.05; 30%-40%) and increased the expression of cannabinoid receptor 1 (P < 0.05; 31%). Furthermore, the high ratio increased ROS production (P < 0.01; 74%-115%) and reduced mitochondrial respiratory functions such as basal and maximal respiration, ATP production, spare respiratory capacity and proton leak (P < 0.01; 35%-68%). CONCLUSION: High AA:DHA ratio induced triglyceride accumulation, increased oxidative stress and disrupted mitochondrial functions. Stimulation of lipogenic and steroidal transcription factors may partly mediate these effects and contribute to NAFLD development.

Hepcidin secretion was not directly proportional to intracellular iron-loading in recombinant-TfR1 HepG2 cells: short communication.

Hepcidin is the master regulator of systemic iron homeostasis and its dysregulation is observed in several chronic liver diseases. Unlike the extracellular iron-sensing mechanisms, the intracellular iron-sensing mechanisms in the hepatocytes that lead to hepcidin induction and secretion are incompletely understood. Here, we aimed to understand the direct role of intracellular iron-loading on hepcidin mRNA and peptide secretion using our previously characterised recombinant HepG2 cells that over-express the cell-surface iron-importer protein transferrin receptor-1. Gene expression of hepcidin (HAMP) was determined by real-time PCR. Intracellular iron levels and secreted hepcidin peptide levels were measured by ferrozine assay and immunoassay, respectively. These measurements were compared in the recombinant and wild-type HepG2 cells under basal conditions at 30 min, 2 h, 4 h and 24 h. Data showed that in the recombinant cells, intracellular iron content was higher than wild-type cells at 30 min (3.1-fold, p < 0.01), 2 h (4.6-fold, p < 0.01), 4 h (4.6-fold, p < 0.01) and 24 h (1.9-fold, p < 0.01). Hepcidin (HAMP) mRNA expression was higher than wild-type cells at 30 min (5.9-fold; p = 0.05) and 24 h (6.1-fold; p < 0.03), but at 4 h, the expression was lower than that in wild-type cells (p < 0.05). However, hepcidin secretion levels in the recombinant cells were similar to those in wild-type cells at all time-points, except at 4 h, when the level was lower than wild-type cells (p < 0.01). High intracellular iron in recombinant HepG2 cells did not proportionally increase hepcidin peptide secretion. This suggests a limited role of elevated intracellular iron in hepcidin secretion.

Iron and liver fibrosis: Mechanistic and clinical aspects.

Liver fibrosis is characterised by excessive deposition of extracellular matrix that interrupts normal liver functionality. It is a pathological stage in several untreated chronic liver diseases such as the iron overload syndrome hereditary haemochromatosis, viral hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis and diabetes. Interestingly, regardless of the aetiology, iron-loading is frequently observed in chronic liver diseases. Excess iron can feed the Fenton reaction to generate unquenchable amounts of free radicals that cause grave cellular and tissue damage and thereby contribute to fibrosis. Moreover, excess iron can induce fibrosis-promoting signals in the parenchymal and non-parenchymal cells, which accelerate disease progression and exacerbate liver pathology. Fibrosis regression is achievable following treatment, but if untreated or unsuccessful, it can progress to the irreversible cirrhotic stage leading to organ failure and hepatocellular carcinoma, where resection or transplantation remain the only curative options. Therefore, understanding the role of iron in liver fibrosis is extremely essential as it can help in formulating iron-related diagnostic, prognostic and treatment strategies. These can be implemented in isolation or in combination with the current approaches to prepone detection, and halt or decelerate fibrosis progression before it reaches the irreparable stage. Thus, this review narrates the role of iron in liver fibrosis. It examines the underlying mechanisms by which excess iron can facilitate fibrotic responses. It describes the role of iron in various clinical pathologies and lastly, highlights the significance and potential of iron-related proteins in the diagnosis and therapeutics of liver fibrosis.

Iron Enhances Hepatic Fibrogenesis and Activates Transforming Growth Factor-ß Signaling in Murine Hepatic Stellate Cells.

BACKGROUND: Although excess iron induces oxidative stress in the liver, it is unclear whether it directly activates the hepatic stellate cells (HSC). MATERIALS AND METHODS: We evaluated the effects of excess iron on fibrogenesis and transforming growth factor beta (TGF-ß) signaling in murine HSC. Cells were treated with holotransferrin (0.005-5g/L) for 24 hours, with or without the iron chelator deferoxamine (10µM). Gene expressions (α-SMA, Col1-α1, Serpine-1, TGF-ß, Hif1-α, Tfrc and Slc40a1) were analyzed by quantitative real time-polymerase chain reaction, whereas TfR1, ferroportin, ferritin, vimentin, collagen, TGF-ß RII and phospho-Smad2 proteins were evaluated by immunofluorescence, Western blot and enzyme-linked immunosorbent assay. RESULTS: HSC expressed the iron-uptake protein transferrin receptor 1 (TfR1) and the iron-export protein ferroportin. Holotransferrin upregulated TfR1 expression by 1.8-fold (P < 0.03) and ferritin accumulation (iron storage) by 2-fold (P < 0.01), and activated HSC with 2-fold elevations (P < 0.03) in α-SMA messenger RNA and collagen secretion, and a 1.6-fold increase (P < 0.01) in vimentin protein. Moreover, holotransferrin activated the TGF-ß pathway with TGF-ß messenger RNA elevated 1.6-fold (P = 0.05), and protein levels of TGF-ß RII and phospho-Smad2 increased by 1.8-fold (P < 0.01) and 1.6-fold (P < 0.01), respectively. In contrast, iron chelation decreased ferritin levels by 30% (P < 0.03), inhibited collagen secretion by 60% (P < 0.01), repressed fibrogenic genes α-SMA (0.2-fold; P < 0.05) and TGF-ß (0.4-fold; P < 0.01) and reduced levels of TGF-ß RII and phospho-Smad2 proteins. CONCLUSIONS: HSC express iron-transport proteins. Holotransferrin (iron) activates HSC fibrogenesis and the TGF-ß pathway, whereas iron depletion by chelation reverses this, suggesting that this could be a useful adjunct therapy for patients with fibrosis. Further studies in primary human HSC and animal models are necessary to confirm this.

Erratum to: HFE mRNA expression is responsive to intracellular and extracellular iron loading: short communication.

The original article has been changed to reflect the correct co-author name: Sebastien Farnaud. The original article was corrected.

HFE mRNA expression is responsive to intracellular and extracellular iron loading: short communication.

In liver hepatocytes, the HFE gene regulates cellular and systemic iron homeostasis by modulating cellular iron-uptake and producing the iron-hormone hepcidin in response to systemic iron elevation. However, the mechanism of iron-sensing in hepatocytes remain enigmatic. Therefore, to study the effect of iron on HFE and hepcidin (HAMP) expressions under distinct extracellular and intracellular iron-loading, we examined the effect of holotransferrin treatment (1, 2, 5 and 8 g/L for 6 h) on intracellular iron levels, and mRNA expressions of HFE and HAMP in wild-type HepG2 and previously characterized iron-loaded recombinant-TfR1 HepG2 cells. Gene expression was analyzed by real-time PCR and intracellular iron was measured by ferrozine assay. Data showed that in the wild-type cells, where intracellular iron content remained unchanged, HFE expression remained unaltered at low holotransferrin treatments but was upregulated upon 5 g/L (p < 0.04) and 8 g/L (p = 0.05) treatments. HAMP expression showed alternating elevations and increased upon 1 g/L (p < 0.05) and 5 g/L (p < 0.05). However, in the recombinant cells that showed higher intracellular iron levels than wild-type cells, HFE and HAMP expressions were elevated only at low 1 g/L treatment (p < 0.03) and were repressed at 2 g/L treatment (p < 0.03). Under holotransferrin-untreated conditions, the iron-loaded recombinant cells showed higher expressions of HFE (p < 0.03) and HAMP (p = 0.05) than wild-type cells. HFE mRNA was independently elevated by extracellular and intracellular iron-excess. Thus, it may be involved in sensing both, extracellular and intracellular iron. Repression of HAMP expression under simultaneous intracellular and extracellular iron-loading resembles non-hereditary iron-excess pathologies.