Objective The aim of this study was to explore the role and mechanism of ferroptosis in SiO_(2)-induced cardiac injury using a mouse model.Methods Male C57BL/6 mice were intratracheally instilled with SiO_(2) to creat...Objective The aim of this study was to explore the role and mechanism of ferroptosis in SiO_(2)-induced cardiac injury using a mouse model.Methods Male C57BL/6 mice were intratracheally instilled with SiO_(2) to create a silicosis model.Ferrostatin-1(Fer-1)and deferoxamine(DFO)were used to suppress ferroptosis.Serum biomarkers,oxidative stress markers,histopathology,iron content,and the expression of ferroptosis-related proteins were assessed.Results SiO_(2) altered serum cardiac injury biomarkers,oxidative stress,iron accumulation,and ferroptosis markers in myocardial tissue.Fer-1 and DFO reduced lipid peroxidation and iron overload,and alleviated SiO_(2)-induced mitochondrial damage and myocardial injury.SiO_(2) inhibited Nuclear factor erythroid 2-related factor 2(Nrf2)and its downstream antioxidant genes,while Fer-1 more potently reactivated Nrf2 compared to DFO.Conclusion Iron overload-induced ferroptosis contributes to SiO_(2)-induced cardiac injury.Targeting ferroptosis by reducing iron accumulation or inhibiting lipid peroxidation protects against SiO_(2) cardiotoxicity,potentially via modulation of the Nrf2 pathway.展开更多
Thalamic hemorrhage can lead to the development of central post-stroke pain.Changes in histone acetylation levels,which are regulated by histone deacetylases,affect the excitability of neurons surrounding the hemorrha...Thalamic hemorrhage can lead to the development of central post-stroke pain.Changes in histone acetylation levels,which are regulated by histone deacetylases,affect the excitability of neurons surrounding the hemorrhagic area.However,the regulato ry mechanism of histone deacetylases in central post-stroke pain remains unclea r.Here,we show that iron overload leads to an increase in histone deacetylase 2expression in damaged ventral posterolateral nucleus neurons.Inhibiting this increase restored histone H3 acetylation in the Kcna2 promoter region of the voltage-dependent potassium(Kv)channel subunit gene in a rat model of central post-stroke pain,thereby increasing Kcna2expression and relieving central pain.However,in the absence of nerve injury,increasing histone deacetylase 2 expression decreased Kcna2expression,decreased Kv current,increased the excitability of neurons in the ventral posterolateral nucleus area,and led to neuropathic pain symptoms.Moreover,treatment with the iron chelator deferiprone effectively reduced iron overload in the ventral posterolateral nucleus after intracerebral hemorrhage,reversed histone deacetylase 2 upregulation and Kv1.2 downregulation,and alleviated mechanical hypersensitivity in central post-stroke pain rats.These results suggest that histone deacetylase 2 upregulation and Kv1.2 downregulation,mediated by iron overload,are important factors in central post-stroke pain pathogenesis and co uld se rve as new to rgets for central poststroke pain treatment.展开更多
Increasing evidence indicates that disruption of normal iron homeostasis may contribute to pathological development of Alzheimer's disease.Icariin,astragalus,and puerarin have been shown to suppress iron overload in ...Increasing evidence indicates that disruption of normal iron homeostasis may contribute to pathological development of Alzheimer's disease.Icariin,astragalus,and puerarin have been shown to suppress iron overload in the cerebral cortex and improve spatial learning and memory disorders in Alzheimer's disease mice,although the underlying mechanism remains unclear.In the present study,APPswe/PS1ΔE9 transgenic mice were administered icariin,astragalus,and puerarin(120,80,and 80 mg/kg,respectively,once a day,for 3 months).Iron levels were detected by flame atomic absorption spectroscopy.Interleukin-1β,interleukin-6,and tumor necrosis factor-α levels were measured in the cerebral cortex by enzyme linked immunosorbent assay.Glutathione peroxidase and superoxide dismutase activity and malondialdehyde content were determined by colorimetry.Our results demonstrate that after treatment,iron levels and malondialdehyde content are decreased,while glutathione peroxidase and superoxide dismutase activities are increased.Further,interleukin-1β,interleukin-6,and tumor necrosis factor-α levels were reduced.These results confirm that compounds of icariin,astragalus,and puerarin may alleviate iron overload by reducing oxidative stress and the inflammatory response.展开更多
BACKGROUND: The liver, as the main iron storage compart-ment and the place of hepcidin synthesis, is the central organ involved in maintaining iron homeostasis in the body. Exces-sive accumulation of iron is an import...BACKGROUND: The liver, as the main iron storage compart-ment and the place of hepcidin synthesis, is the central organ involved in maintaining iron homeostasis in the body. Exces-sive accumulation of iron is an important risk factor in liver disease progression to cirrhosis and hepatocellular carcinoma. Here, we review the literature on the molecular pathogenesis of iron overload and its clinical consequences in chronic liver diseases. DATA SOURCES: PubMed was searched for English-language articles on molecular genesis of primary and secondary iron overload, as well as on their association with liver disease pro-gression. We have also included literature on adjuvant thera-peutic interventions aiming to alleviate detrimental effects of excessive body iron load in liver cirrhosis. RESULTS: Excess of free, unbound iron induces oxidative stress, increases cell sensitivity to other detrimental factors, and can directly affect cellular signaling pathways, resulting in accelerated liver disease progression. Diagnosis of liver cirrhosis is, in turn, often associated with the identiifcation of a pathological accumulation of iron, even in the absence of genetic background of hereditary hemochromatosis. Iron depletion and adjuvant therapy with antioxidants are shown to cause signiifcant improvement of liver functions in patients with iron overload. Phlebotomy can have beneifcial effects on liver histology in patients with excessive iron accumulation combined with compensated liver cirrhosis of different etiology. CONCLUSION: Excessive accumulation of body iron in liver cirrhosis is an important predictor of liver failure and avail-able data suggest that it can be considered as target for adju-vant therapy in this condition.展开更多
Objective: To investigate the electrophysiology effects and mechanism of iron overload on the slow response autorhythmic cells in the left ventricular outflow tract of guinea pigs.Methods: Standard microelectrode cell...Objective: To investigate the electrophysiology effects and mechanism of iron overload on the slow response autorhythmic cells in the left ventricular outflow tract of guinea pigs.Methods: Standard microelectrode cell recording techniques were adopted to observe the electrophysiological effects of different concentrations of Fe^(2+)(100 μmol/L, 200 μmol/L) on the left ventricular outflow tract autorhythmic cells.Heart tissues were perfused with FeSO_4(200 μmol/L) combing with CaCl_2(4.2 mmol/L), Verapamil,(1 μmol/L), and nickel chloride(200μmol/L) respectively to observe the influences of these contents on electrophysiology of FeSO_4(200μmol/L) on the left ventricular outflow tract autorhythmic cells.Results: Fe^(2+)at both 100 μmol/L and 200 μmol/L could change the electrophysiological parameters of the slow response autorhythmic cells of the left ventricular outflow tract in a concentrationdependent manner resulting into decrease in Vmax, APA and MDP, slower RPF and VDD, and prolonged APD_(50) and APD_(90)(P all <0.05).Besides, perfusion of increased Ca^(2+) concentration could partially offset the electrophysiological effects of Fe^(2+)(200 μmol/L).The L-type calcium channel(LTCC) blocker Verapamil(1 μmol/L) could block the electrophysiological effects of Fe^(2+)(200 μmol/L).But the T-type calcium channel(TTCC) blocker nickel chloride(NiCl_2, 200 μmol/L) could not block the electrophysiological effects of Fe^(2+)(200 μmol/L).Conclusions: Fe^(2+) can directly change the electrophysiological characteristics of the slow response autorhythmic cells of the left ventricular outflow tract probably through the L-type calcium channel.展开更多
BACKGROUND:Increased liver iron stores may contribute to the progression of liver injury and fibrosis,and are associated with a higher risk of hepatocellular carcinoma development.Pre-transplant symptoms of iron overl...BACKGROUND:Increased liver iron stores may contribute to the progression of liver injury and fibrosis,and are associated with a higher risk of hepatocellular carcinoma development.Pre-transplant symptoms of iron overload in patients with liver cirrhosis are associated with higher risk of infectious and malignant complications in liver transplant recipients.HFE gene mutations may be involved in the pathogenesis of liver iron overload and influence the progression of chronic liver diseases of different origins.This study was designed to determine the prevalence of iron overload in relation to HFE gene mutations among Polish patients with liver cirrhosis.METHODS:Sixty-one patients with liver cirrhosis included in the study were compared with a control group of 42 consecutive patients subjected to liver biopsy because of chronic liver diseases.Liver function tests and serum iron markers were assessed in both groups.All patients were screened for HFE mutations (C282Y,H63D,S65C).Thirty-six of 61 patients from the study group and all controls had liver biopsy performed with semiquantitative assessment of iron deposits in hepatocytes.RESULTS:The biochemical markers of iron overload and iron deposits in the liver were detected with a higher frequency (70% and 47% respectively) in patients with liver cirrhosis.There were no differences in the prevalence of all HFE mutations in both groups.In patients with a diagnosis of hepatocellular carcinoma,no significant associations with iron disorders and HFE gene mutations were found.CONCLUSIONS:Iron disorders were detected in patients with liver cirrhosis frequently but without significant association with HFE gene mutations.Only the homozygous C282Y mutation seems to occur more frequently in the selected population of patients with liver cirrhosis.As elevated biochemical iron indices accompanied liver iron deposits more frequently in liver cirrhosis compared to controls with chronic liver disease,there is a need for more extensive studies searching for the possible influence of non-HFE iron homeostasis regulators and their modulation on the course of chronic liver disease and liver cirrhosis.展开更多
BACKGROUND: Liver steatosis and iron overload, which are frequently observed in chronic hepatitis C (CHC), may contribute to the progression of liver injury. This study aimed to evaluate the correlation between liver ...BACKGROUND: Liver steatosis and iron overload, which are frequently observed in chronic hepatitis C (CHC), may contribute to the progression of liver injury. This study aimed to evaluate the correlation between liver steatosis and iron overload in Polish patients with CHC compared to non- alcoholic fatty liver disease (NAFLD) and HFE-hereditary hemochromatosis (HH) patients. METHODS: A total of 191 CHC patients were compared with 67 NAFLD and 21 HH patients. Liver function tests, serum markers of iron metabolism, cholesterol and triglycerides were assayed. The inflammatory activity, fibrosis, iron deposits and steatosis stages were assessed in liver specimens. HFE gene polymorphisms were investigated by PCR-RFLP. RESULTS: Liver steatosis was associated with obesity and diabetes mellitus. This disease was confirmed in 76/174 (44%) CHC patients, most of whom were infected with genotype 1. The average grade of steatosis was higher in NAFLD patients. CHC patients had significantly higher iron concentrations and transferrin saturations than NAFLD patients. Compared with CHC patients, HH patients had higher values of serum iron parameters and more intensive hepatocyte iron deposits without differences in the prevalence and intensity of liver steatosis. In the CHC group, lipids accumulation in hepatocytes was significantly associated with the presence of serummarkers of iron overload. No correlation between the HFE gene polymorphism and liver steatosis in CHC patients was found. CONCLUSIONS: Liver steatosis was diagnosed in nearly half of CHC patients, most of whom were infected with genotype 1. The intensity of steatosis was lower in CHC patients than that in NAFLD patients because of a less frequent diagnosis of metabolic syndrome. Only in CHC patients were biochemical markers of iron accumulation positively correlated with liver steatosis; these findings were independent of HFE gene mutations.展开更多
Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be a...Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be associated with oxidative stress and the NF-E2-related factor 2 (Nrf2)/ARE signaling pathway. As an in vitro cellular model of diabetic peripheral neuropathy, PC12 cells ex- posed to high glucose concentration were used in this study. PC12 cells were cultured with ferric ammonium citrate at different concentrations to create iron overload. PC12 cells cultured in ferric ammonium citrate under high glucose concentration had significantly low cell viability, a high rate of apoptosis, and elevated reactive oxygen species and malondialdehyde levels. These changes were dependent on ferric ammonium citrate concentration. Nrf2 mRNA and protein expression in the ferric ammonium citrate groups were inhibited markedly in a dose-dependent manner. All changes could be inhibited by addition of deferoxamine. These results indicate that iron overload aggravates oxidative stress injury in neural cells under high glucose concentration and that the Nrf2/ARE sigfnaling pathway might play an important role in this process.展开更多
Despite its various vital roles in the different body’s metabolisms,iron may have a hazardous impact on health when it exceeds its normal values.Iron overload is triggered by many genetic and behavioral factors.Furth...Despite its various vital roles in the different body’s metabolisms,iron may have a hazardous impact on health when it exceeds its normal values.Iron overload is triggered by many genetic and behavioral factors.Furthermore,excessive iron levels have also been observed in many pathologies such as Alzheimer’s,Parkinson’s,cardiovascular and some cancerous diseases.This paper describes a set of natural iron chelators as an effective and a safe orthomolecular approach in chelating iron.Orthomolecular medicine is based on providing patients with nutritional supplementation at high doses to treat and prevent diseases.This paper describes the properties of a set of flavonoids and phenolic acids such as curcumin and ferulic acid that can be administered as supplements to patients suffering from iron overload since they are classified as strong chelators.Those natural iron chelators’supplements are mainly extracted from fruits,vegetables,and plants.As chelators,they are able to bind effectively to iron,inhibit the production of reactive oxygen species,and reduce the levels of oxidative stress.They can also play an effective therapeutic role in the treatment of neurodegenerative,cardiovascular,diabetic,and cancerous diseases thanks to their iron chelation,antioxidant,and anti-inflammatory properties.展开更多
AIM: The pathogenesis of occurrence of liver inflammation and fibrosis in patients with nonalcoholic steatohepatitis (NASH) is not completely understood. Other than insulin resistance, iron abnormalities have been tho...AIM: The pathogenesis of occurrence of liver inflammation and fibrosis in patients with nonalcoholic steatohepatitis (NASH) is not completely understood. Other than insulin resistance, iron abnormalities have been thought to be one of the triggering factors. Therefore, our aim was to study the role of iron abnormalities and HFE gene mutations in patients with NASH.METHODS: Thirty-one patients of NASH diagnosed on the basis of clinical examination biochemistry, ultrasonography and liver biopsy (n = 14) were included in the study. Serum iron parameters (n = 23) (iron, ferritin, total iron-binding capacity and transferrin saturation), Peris' iron staining on liver biopsies (n = 14) and HFE gene mutations (C282Y and H63D) (n = 16) were studied in these patients. The association between iron staining, necroinflammatory activity and fibrosis stage on liver biopsies was also determined.RESULTS: Elevated serum iron, ferritin and transferrin saturation above 55% were observed in 4.3% of patients.On histology, 71% of the patients had negative iron staining,21.4% had 1+ staining, 7.2% had 2+ staining and none had 3+ or 4+ staining. There was no association between the degree of iron staining and necroinflammatory activity (P = 0.55) and fibrosis stage (P = 0.09) on histology. None of the patients had C282Y HFE gene mutation and four patients (25%) were found to be heterozygotes for H63D gene mutation.CONCLUSION: Our study does not favor iron overload and HFE gene mutations as major factors in the pathogenesis of NASH in Asian Indians.展开更多
Iron overload is reported to be associated with immune alterations and increased susceptibility to infections. HIV infection is characterized by progressive immunodeficiency leading to invasion by opportunistic pathog...Iron overload is reported to be associated with immune alterations and increased susceptibility to infections. HIV infection is characterized by progressive immunodeficiency leading to invasion by opportunistic pathogens. It was of interest to find out if disease course in HIV type-1 infection could have any relation with alteration in body iron status among individuals with history of oral iron intake. A follow-up study of immunologic and virologic markers in relation to disease progression was undertaken on asymptomatic HIV-1 positive blood donors with history of oral iron intake (subgroup I) compared to those without such history (subgroup II). High serum iron was associated with elevated levels of Th2 category of cytokines, heightened immune activation, faster decline in CD4 + T lymphocyte count and higher viral set point. Pulmonary tuberculosis (PT) was the most common AIDS related illness (ARI) (>70%) recorded among subgroup I compared to non-PT category of ARI. Median ARI free duration (months) was shorter among those who developed PT compared to those developing non-PT category of ARI i.e. 30 (95% CI as 26,32) versus 67(95% CI as 60,71) in subgroup I and 47 (95% CI as 42,49) versus 80 (95% CI as 72,87) in subgroup II (P P < 0.001 for PT versus non-PT in both subgroups). The present study indicates that body iron overload resulting from excess intake of iron may be associated with qualitative defects in cell mediated immunity at early stage of HIV-1 infection that may facilitate subsequent acquisition of pulmonary tuberculosis, shorter ARI free duration and reduced survival.展开更多
Nonspherocytic hereditary anemias are occasionally accompanied by significant iron overload but the significance for the development of chronic liver disease is not clear. We described two cases of patients with chron...Nonspherocytic hereditary anemias are occasionally accompanied by significant iron overload but the significance for the development of chronic liver disease is not clear. We described two cases of patients with chronic liver d isease and severeiron overload due to chronic hereditary hemolysis. Both patients have had signs of liver cirrhosis and severe hemolysis since childhood. A hereditary pyruvate kinase deficiency (PKD) was discovered as the underlying reason for the hemolysis.Sequencing of the pyruvate kinase gene showed a mutation within exon 11. Liver histology in both patients revealed cirrhosis and a severe iron overload but primary hemochromatosis was excluded by HFE-gene analysis.An iron reduction therapy with desferrioxamine led to significant decrease of serum ferritin and sustained clinical improvement. PKD-induced hemolysis may cause severe iron overload even in the absence of HFE-genotype abnormalities. This secondary iron overload can lead to chronic liver disease and cirrhosis. Therefore, the iron metabolism of PKD patients has to be closely monitored and iron overload should be consequently treated.展开更多
Iron overload increases the risk of diabetes via mechanisms of abnormal glucose metabolism: insulin deficiency, insulin resistance, and/or hepatic dysfunction. Iron reduction upregulates glucose uptake and improves he...Iron overload increases the risk of diabetes via mechanisms of abnormal glucose metabolism: insulin deficiency, insulin resistance, and/or hepatic dysfunction. Iron reduction upregulates glucose uptake and improves hepatocytes insulin receptor activity. This study was conducted to examine the effects of iron depletion—via controlled phlebotomy—on the hypoglycemic treatment in poorly controlled type 2 diabetes mellitus (T2DM) patients with non-genetic iron overload. Forty three patients with poorly controlled T2DM and iron overload were divided into 2 groups: iron depletion group and control group. Regular phlebotomy was performed for iron depletion group on monthly basis until serum ferritin reached 20 μg/L or less. Both groups were examined and compared for blood pressure, serum ferritin, lipid profile, HFE-gene, HbA1c, HOMA-IR and number of medicines used for diabetic control. The results had revealed that group differences of HbA1c (-2.64, 95% CI -3.23 to 2.04, p < 0.001) and HOMA-IR (-0.68, 95% CI -0.98 to -0.37, p < 0.001) showed significant decreases in iron depletion group at end of study. Significant decrease in the numbers of hypoglycemic medicines in iron depletion group was shown at end of study (p < 0.001);66.7% of iron depletion group patients were receiving 1 or 2 medicines at end of studyversus none of the control group. Diastolic blood pressure (DBP), triglycerides and LDL-C decreased significantly while HDL-C levels showed significant rise after iron depletion. It can be concluded from the present study that iron depletion therapy is beneficial for improving the efficiency of glycemic control, DBP, and dyslipidemia in poorly controlled type 2 diabetics with iron over load.展开更多
We report the case of a 7 years old girl with Juvenile Hemochromatosis, due to homozygous mutation of HJV, which had increased serum iron indices and liver iron overload in the absence of any clinical sign of disease....We report the case of a 7 years old girl with Juvenile Hemochromatosis, due to homozygous mutation of HJV, which had increased serum iron indices and liver iron overload in the absence of any clinical sign of disease. Oral iron chelation with low dose deferasirox showed good efficacy and no side effects. The oral iron chelator deferasirox could be a valid option for removing excess iron in early Juvenile Hemochromatosis.展开更多
AIM: To re-evaluate the diagnostic criteria of insulin resistance hepatic iron overload based on clinical, biochemical and histopathological findings. METHODS: We studied 81 patients with hepatic iron overload not exp...AIM: To re-evaluate the diagnostic criteria of insulin resistance hepatic iron overload based on clinical, biochemical and histopathological findings. METHODS: We studied 81 patients with hepatic iron overload not explained by known genetic and acquired causes. The metabolic syndrome (MS) was defined according to ATPⅢ criteria. Iron overload was assessed by liver biopsy. Liver histology was evaluated by Ishak's score and iron accumulation by Deugnier's score; steatosis was diagnosed when present in ≥ 5% of hepatocytes. RESULTS: According to transferrin saturation levels, we observed significant differences in the amount of hepatic iron overload and iron distribution, as well as the number of metabolic abnormalities. Using Receiving Operating Curve analysis, we found that the presence of two components of the MS differentiatedtwo groups with a statistically significant different hepatic iron overload (P < 0.0001). Patients with ≥ 2 metabolic alterations and steatosis had lower amount of hepatic iron, lower transferrin saturation and higher sinusoidal iron than patients with < 2 MS components and absence of steatosis. CONCLUSION: In our patients, the presence of ≥ 2 alterations of the MS and hepatic steatosis was associated with a moderate form of iron overload with a prevalent sinusoidal distribution and a normal transferrin saturation, suggesting the existence of a peculiar pathogenetic mechanism of iron accumulation. These patients may have the typical dysmetabolic iron overload syndrome. By contrast, patients with transferrin saturation ≥ 60% had more severe iron overload, few or no metabolic abnormalities and a hemochromatosis-like pattern of iron overload.展开更多
Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are promising effective iron chelators for the treatment of iron overload in b-thalassemia patients;nonetheless, their side effects have also been reporte...Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are promising effective iron chelators for the treatment of iron overload in b-thalassemia patients;nonetheless, their side effects have also been reported. 3-Hydroxypyridinone derivatives are being developed as a safer new chelator and in combined chelation therapy. We evaluated the iron-chelating activity of 1-(N-acetyl-6-aminohexyl)-3-hydroxypyridin-4-one (CM1) in iron-loaded C57BL6 mice. The feeding of a ferrocene-supplemented diet (Fe diet) to mice resulted in iron overload, detectable plasma nontransferrin-bound iron (NTBI) and labile plasma iron (LPI), and increases of red cell membrane iron, plasma malondialdehyde (MDA) and excessive tissue iron deposits. Like DFP, the CM1 lowered the levels of the membrane non-heme iron, the NTBI and LPI (p < 0.05) and the MDA after 3 months of treatment. Administration of the Fe diet and the Fe diet along with the chelators did not change the morphology of the liver and heart. Numerous iron accumulations were observed in the liver and spleen tissues of the Fe dietfed mice, whereas the CM1 reduced such iron deposition. Thus, 1-(N-acetyl-6-aminohexyl)-3-hydro- xypyridin-4-one (CM1) can be considered a candidate bidentate oral iron chelator and is effective in the removal of toxic irons in blood compartment and tissues. The effectiveness and toxicity of the CM1 need to be investigated extensively in thalassemia mice and patients with iron overload.展开更多
Iron overload is a condition involving excessive iron deposit in various organs,the liver being the main target organ for iron deposition and overload which are associated with significant liver morbidity and mortalit...Iron overload is a condition involving excessive iron deposit in various organs,the liver being the main target organ for iron deposition and overload which are associated with significant liver morbidity and mortality.Iron overload can be categorized into primary and secondary causes.Primary iron overload,so-called hereditary hemochromatosis,is a wellrecognized disease with available standard treatment recommendations.However,secondary iron overload is a more diverse disease with many unclear areas to be explored.Secondary iron overload is more prevalent than primary iron overload and occurs as a consequence of various causes which differ significantly across geographic regions.The main causes of secondary iron overload are iron-loading anemias,and chronic liver disease.The liver-related outcomes,patient outcomes,and treatment recommendations in these patients differ depending on the cause of iron overload.This review summarizes the causes,pathophysiology,liver-related outcomes,disease outcomes,and treatments of secondary iron overload.展开更多
基金supported by the National Natural Science Foundation of China[No.U21A20334,82373544]Hebei Provincial Department of Science and Technology Centrally Guided Local Development Fund Project[236Z7705G]Occupational health risk assessment and the formulation of national occupational health standards[102393220020090000020].
文摘Objective The aim of this study was to explore the role and mechanism of ferroptosis in SiO_(2)-induced cardiac injury using a mouse model.Methods Male C57BL/6 mice were intratracheally instilled with SiO_(2) to create a silicosis model.Ferrostatin-1(Fer-1)and deferoxamine(DFO)were used to suppress ferroptosis.Serum biomarkers,oxidative stress markers,histopathology,iron content,and the expression of ferroptosis-related proteins were assessed.Results SiO_(2) altered serum cardiac injury biomarkers,oxidative stress,iron accumulation,and ferroptosis markers in myocardial tissue.Fer-1 and DFO reduced lipid peroxidation and iron overload,and alleviated SiO_(2)-induced mitochondrial damage and myocardial injury.SiO_(2) inhibited Nuclear factor erythroid 2-related factor 2(Nrf2)and its downstream antioxidant genes,while Fer-1 more potently reactivated Nrf2 compared to DFO.Conclusion Iron overload-induced ferroptosis contributes to SiO_(2)-induced cardiac injury.Targeting ferroptosis by reducing iron accumulation or inhibiting lipid peroxidation protects against SiO_(2) cardiotoxicity,potentially via modulation of the Nrf2 pathway.
基金supported by the National Natural Science Foundation of China,Nos.U2004106 (to WY),81971061 (to JC)the Key Scientific Research Project of Colleges and Universities in Henan Province,No.21A320039 (to WY)。
文摘Thalamic hemorrhage can lead to the development of central post-stroke pain.Changes in histone acetylation levels,which are regulated by histone deacetylases,affect the excitability of neurons surrounding the hemorrhagic area.However,the regulato ry mechanism of histone deacetylases in central post-stroke pain remains unclea r.Here,we show that iron overload leads to an increase in histone deacetylase 2expression in damaged ventral posterolateral nucleus neurons.Inhibiting this increase restored histone H3 acetylation in the Kcna2 promoter region of the voltage-dependent potassium(Kv)channel subunit gene in a rat model of central post-stroke pain,thereby increasing Kcna2expression and relieving central pain.However,in the absence of nerve injury,increasing histone deacetylase 2 expression decreased Kcna2expression,decreased Kv current,increased the excitability of neurons in the ventral posterolateral nucleus area,and led to neuropathic pain symptoms.Moreover,treatment with the iron chelator deferiprone effectively reduced iron overload in the ventral posterolateral nucleus after intracerebral hemorrhage,reversed histone deacetylase 2 upregulation and Kv1.2 downregulation,and alleviated mechanical hypersensitivity in central post-stroke pain rats.These results suggest that histone deacetylase 2 upregulation and Kv1.2 downregulation,mediated by iron overload,are important factors in central post-stroke pain pathogenesis and co uld se rve as new to rgets for central poststroke pain treatment.
基金supported by the National Natural Science Foundation of China,No.81273983
文摘Increasing evidence indicates that disruption of normal iron homeostasis may contribute to pathological development of Alzheimer's disease.Icariin,astragalus,and puerarin have been shown to suppress iron overload in the cerebral cortex and improve spatial learning and memory disorders in Alzheimer's disease mice,although the underlying mechanism remains unclear.In the present study,APPswe/PS1ΔE9 transgenic mice were administered icariin,astragalus,and puerarin(120,80,and 80 mg/kg,respectively,once a day,for 3 months).Iron levels were detected by flame atomic absorption spectroscopy.Interleukin-1β,interleukin-6,and tumor necrosis factor-α levels were measured in the cerebral cortex by enzyme linked immunosorbent assay.Glutathione peroxidase and superoxide dismutase activity and malondialdehyde content were determined by colorimetry.Our results demonstrate that after treatment,iron levels and malondialdehyde content are decreased,while glutathione peroxidase and superoxide dismutase activities are increased.Further,interleukin-1β,interleukin-6,and tumor necrosis factor-α levels were reduced.These results confirm that compounds of icariin,astragalus,and puerarin may alleviate iron overload by reducing oxidative stress and the inflammatory response.
基金supported by a grant from Polish National Science Centre(2011/01/B/NZ6/00320)
文摘BACKGROUND: The liver, as the main iron storage compart-ment and the place of hepcidin synthesis, is the central organ involved in maintaining iron homeostasis in the body. Exces-sive accumulation of iron is an important risk factor in liver disease progression to cirrhosis and hepatocellular carcinoma. Here, we review the literature on the molecular pathogenesis of iron overload and its clinical consequences in chronic liver diseases. DATA SOURCES: PubMed was searched for English-language articles on molecular genesis of primary and secondary iron overload, as well as on their association with liver disease pro-gression. We have also included literature on adjuvant thera-peutic interventions aiming to alleviate detrimental effects of excessive body iron load in liver cirrhosis. RESULTS: Excess of free, unbound iron induces oxidative stress, increases cell sensitivity to other detrimental factors, and can directly affect cellular signaling pathways, resulting in accelerated liver disease progression. Diagnosis of liver cirrhosis is, in turn, often associated with the identiifcation of a pathological accumulation of iron, even in the absence of genetic background of hereditary hemochromatosis. Iron depletion and adjuvant therapy with antioxidants are shown to cause signiifcant improvement of liver functions in patients with iron overload. Phlebotomy can have beneifcial effects on liver histology in patients with excessive iron accumulation combined with compensated liver cirrhosis of different etiology. CONCLUSION: Excessive accumulation of body iron in liver cirrhosis is an important predictor of liver failure and avail-able data suggest that it can be considered as target for adju-vant therapy in this condition.
基金supported by Zhangjiakou Project of Science and Technology Studies and Development Planning(Grand No.1321078D)
文摘Objective: To investigate the electrophysiology effects and mechanism of iron overload on the slow response autorhythmic cells in the left ventricular outflow tract of guinea pigs.Methods: Standard microelectrode cell recording techniques were adopted to observe the electrophysiological effects of different concentrations of Fe^(2+)(100 μmol/L, 200 μmol/L) on the left ventricular outflow tract autorhythmic cells.Heart tissues were perfused with FeSO_4(200 μmol/L) combing with CaCl_2(4.2 mmol/L), Verapamil,(1 μmol/L), and nickel chloride(200μmol/L) respectively to observe the influences of these contents on electrophysiology of FeSO_4(200μmol/L) on the left ventricular outflow tract autorhythmic cells.Results: Fe^(2+)at both 100 μmol/L and 200 μmol/L could change the electrophysiological parameters of the slow response autorhythmic cells of the left ventricular outflow tract in a concentrationdependent manner resulting into decrease in Vmax, APA and MDP, slower RPF and VDD, and prolonged APD_(50) and APD_(90)(P all <0.05).Besides, perfusion of increased Ca^(2+) concentration could partially offset the electrophysiological effects of Fe^(2+)(200 μmol/L).The L-type calcium channel(LTCC) blocker Verapamil(1 μmol/L) could block the electrophysiological effects of Fe^(2+)(200 μmol/L).But the T-type calcium channel(TTCC) blocker nickel chloride(NiCl_2, 200 μmol/L) could not block the electrophysiological effects of Fe^(2+)(200 μmol/L).Conclusions: Fe^(2+) can directly change the electrophysiological characteristics of the slow response autorhythmic cells of the left ventricular outflow tract probably through the L-type calcium channel.
基金supported by a grant from the Medical University of Gdansk (W-175)
文摘BACKGROUND:Increased liver iron stores may contribute to the progression of liver injury and fibrosis,and are associated with a higher risk of hepatocellular carcinoma development.Pre-transplant symptoms of iron overload in patients with liver cirrhosis are associated with higher risk of infectious and malignant complications in liver transplant recipients.HFE gene mutations may be involved in the pathogenesis of liver iron overload and influence the progression of chronic liver diseases of different origins.This study was designed to determine the prevalence of iron overload in relation to HFE gene mutations among Polish patients with liver cirrhosis.METHODS:Sixty-one patients with liver cirrhosis included in the study were compared with a control group of 42 consecutive patients subjected to liver biopsy because of chronic liver diseases.Liver function tests and serum iron markers were assessed in both groups.All patients were screened for HFE mutations (C282Y,H63D,S65C).Thirty-six of 61 patients from the study group and all controls had liver biopsy performed with semiquantitative assessment of iron deposits in hepatocytes.RESULTS:The biochemical markers of iron overload and iron deposits in the liver were detected with a higher frequency (70% and 47% respectively) in patients with liver cirrhosis.There were no differences in the prevalence of all HFE mutations in both groups.In patients with a diagnosis of hepatocellular carcinoma,no significant associations with iron disorders and HFE gene mutations were found.CONCLUSIONS:Iron disorders were detected in patients with liver cirrhosis frequently but without significant association with HFE gene mutations.Only the homozygous C282Y mutation seems to occur more frequently in the selected population of patients with liver cirrhosis.As elevated biochemical iron indices accompanied liver iron deposits more frequently in liver cirrhosis compared to controls with chronic liver disease,there is a need for more extensive studies searching for the possible influence of non-HFE iron homeostasis regulators and their modulation on the course of chronic liver disease and liver cirrhosis.
基金supported by agrant from Medical University of Gdansk(W-175)
文摘BACKGROUND: Liver steatosis and iron overload, which are frequently observed in chronic hepatitis C (CHC), may contribute to the progression of liver injury. This study aimed to evaluate the correlation between liver steatosis and iron overload in Polish patients with CHC compared to non- alcoholic fatty liver disease (NAFLD) and HFE-hereditary hemochromatosis (HH) patients. METHODS: A total of 191 CHC patients were compared with 67 NAFLD and 21 HH patients. Liver function tests, serum markers of iron metabolism, cholesterol and triglycerides were assayed. The inflammatory activity, fibrosis, iron deposits and steatosis stages were assessed in liver specimens. HFE gene polymorphisms were investigated by PCR-RFLP. RESULTS: Liver steatosis was associated with obesity and diabetes mellitus. This disease was confirmed in 76/174 (44%) CHC patients, most of whom were infected with genotype 1. The average grade of steatosis was higher in NAFLD patients. CHC patients had significantly higher iron concentrations and transferrin saturations than NAFLD patients. Compared with CHC patients, HH patients had higher values of serum iron parameters and more intensive hepatocyte iron deposits without differences in the prevalence and intensity of liver steatosis. In the CHC group, lipids accumulation in hepatocytes was significantly associated with the presence of serummarkers of iron overload. No correlation between the HFE gene polymorphism and liver steatosis in CHC patients was found. CONCLUSIONS: Liver steatosis was diagnosed in nearly half of CHC patients, most of whom were infected with genotype 1. The intensity of steatosis was lower in CHC patients than that in NAFLD patients because of a less frequent diagnosis of metabolic syndrome. Only in CHC patients were biochemical markers of iron accumulation positively correlated with liver steatosis; these findings were independent of HFE gene mutations.
基金supported by the Natural Science Foundation of Hubei Province,No.2010CDB09001
文摘Iron overload can lead to cytotoxicity, and it is a risk factor for diabetic peripheral neuropathy. However, the underlying mechanism remains unclear. We conjectured that iron overload-induced neurotoxicity might be associated with oxidative stress and the NF-E2-related factor 2 (Nrf2)/ARE signaling pathway. As an in vitro cellular model of diabetic peripheral neuropathy, PC12 cells ex- posed to high glucose concentration were used in this study. PC12 cells were cultured with ferric ammonium citrate at different concentrations to create iron overload. PC12 cells cultured in ferric ammonium citrate under high glucose concentration had significantly low cell viability, a high rate of apoptosis, and elevated reactive oxygen species and malondialdehyde levels. These changes were dependent on ferric ammonium citrate concentration. Nrf2 mRNA and protein expression in the ferric ammonium citrate groups were inhibited markedly in a dose-dependent manner. All changes could be inhibited by addition of deferoxamine. These results indicate that iron overload aggravates oxidative stress injury in neural cells under high glucose concentration and that the Nrf2/ARE sigfnaling pathway might play an important role in this process.
文摘Despite its various vital roles in the different body’s metabolisms,iron may have a hazardous impact on health when it exceeds its normal values.Iron overload is triggered by many genetic and behavioral factors.Furthermore,excessive iron levels have also been observed in many pathologies such as Alzheimer’s,Parkinson’s,cardiovascular and some cancerous diseases.This paper describes a set of natural iron chelators as an effective and a safe orthomolecular approach in chelating iron.Orthomolecular medicine is based on providing patients with nutritional supplementation at high doses to treat and prevent diseases.This paper describes the properties of a set of flavonoids and phenolic acids such as curcumin and ferulic acid that can be administered as supplements to patients suffering from iron overload since they are classified as strong chelators.Those natural iron chelators’supplements are mainly extracted from fruits,vegetables,and plants.As chelators,they are able to bind effectively to iron,inhibit the production of reactive oxygen species,and reduce the levels of oxidative stress.They can also play an effective therapeutic role in the treatment of neurodegenerative,cardiovascular,diabetic,and cancerous diseases thanks to their iron chelation,antioxidant,and anti-inflammatory properties.
文摘AIM: The pathogenesis of occurrence of liver inflammation and fibrosis in patients with nonalcoholic steatohepatitis (NASH) is not completely understood. Other than insulin resistance, iron abnormalities have been thought to be one of the triggering factors. Therefore, our aim was to study the role of iron abnormalities and HFE gene mutations in patients with NASH.METHODS: Thirty-one patients of NASH diagnosed on the basis of clinical examination biochemistry, ultrasonography and liver biopsy (n = 14) were included in the study. Serum iron parameters (n = 23) (iron, ferritin, total iron-binding capacity and transferrin saturation), Peris' iron staining on liver biopsies (n = 14) and HFE gene mutations (C282Y and H63D) (n = 16) were studied in these patients. The association between iron staining, necroinflammatory activity and fibrosis stage on liver biopsies was also determined.RESULTS: Elevated serum iron, ferritin and transferrin saturation above 55% were observed in 4.3% of patients.On histology, 71% of the patients had negative iron staining,21.4% had 1+ staining, 7.2% had 2+ staining and none had 3+ or 4+ staining. There was no association between the degree of iron staining and necroinflammatory activity (P = 0.55) and fibrosis stage (P = 0.09) on histology. None of the patients had C282Y HFE gene mutation and four patients (25%) were found to be heterozygotes for H63D gene mutation.CONCLUSION: Our study does not favor iron overload and HFE gene mutations as major factors in the pathogenesis of NASH in Asian Indians.
文摘Iron overload is reported to be associated with immune alterations and increased susceptibility to infections. HIV infection is characterized by progressive immunodeficiency leading to invasion by opportunistic pathogens. It was of interest to find out if disease course in HIV type-1 infection could have any relation with alteration in body iron status among individuals with history of oral iron intake. A follow-up study of immunologic and virologic markers in relation to disease progression was undertaken on asymptomatic HIV-1 positive blood donors with history of oral iron intake (subgroup I) compared to those without such history (subgroup II). High serum iron was associated with elevated levels of Th2 category of cytokines, heightened immune activation, faster decline in CD4 + T lymphocyte count and higher viral set point. Pulmonary tuberculosis (PT) was the most common AIDS related illness (ARI) (>70%) recorded among subgroup I compared to non-PT category of ARI. Median ARI free duration (months) was shorter among those who developed PT compared to those developing non-PT category of ARI i.e. 30 (95% CI as 26,32) versus 67(95% CI as 60,71) in subgroup I and 47 (95% CI as 42,49) versus 80 (95% CI as 72,87) in subgroup II (P P < 0.001 for PT versus non-PT in both subgroups). The present study indicates that body iron overload resulting from excess intake of iron may be associated with qualitative defects in cell mediated immunity at early stage of HIV-1 infection that may facilitate subsequent acquisition of pulmonary tuberculosis, shorter ARI free duration and reduced survival.
文摘Nonspherocytic hereditary anemias are occasionally accompanied by significant iron overload but the significance for the development of chronic liver disease is not clear. We described two cases of patients with chronic liver d isease and severeiron overload due to chronic hereditary hemolysis. Both patients have had signs of liver cirrhosis and severe hemolysis since childhood. A hereditary pyruvate kinase deficiency (PKD) was discovered as the underlying reason for the hemolysis.Sequencing of the pyruvate kinase gene showed a mutation within exon 11. Liver histology in both patients revealed cirrhosis and a severe iron overload but primary hemochromatosis was excluded by HFE-gene analysis.An iron reduction therapy with desferrioxamine led to significant decrease of serum ferritin and sustained clinical improvement. PKD-induced hemolysis may cause severe iron overload even in the absence of HFE-genotype abnormalities. This secondary iron overload can lead to chronic liver disease and cirrhosis. Therefore, the iron metabolism of PKD patients has to be closely monitored and iron overload should be consequently treated.
文摘Iron overload increases the risk of diabetes via mechanisms of abnormal glucose metabolism: insulin deficiency, insulin resistance, and/or hepatic dysfunction. Iron reduction upregulates glucose uptake and improves hepatocytes insulin receptor activity. This study was conducted to examine the effects of iron depletion—via controlled phlebotomy—on the hypoglycemic treatment in poorly controlled type 2 diabetes mellitus (T2DM) patients with non-genetic iron overload. Forty three patients with poorly controlled T2DM and iron overload were divided into 2 groups: iron depletion group and control group. Regular phlebotomy was performed for iron depletion group on monthly basis until serum ferritin reached 20 μg/L or less. Both groups were examined and compared for blood pressure, serum ferritin, lipid profile, HFE-gene, HbA1c, HOMA-IR and number of medicines used for diabetic control. The results had revealed that group differences of HbA1c (-2.64, 95% CI -3.23 to 2.04, p < 0.001) and HOMA-IR (-0.68, 95% CI -0.98 to -0.37, p < 0.001) showed significant decreases in iron depletion group at end of study. Significant decrease in the numbers of hypoglycemic medicines in iron depletion group was shown at end of study (p < 0.001);66.7% of iron depletion group patients were receiving 1 or 2 medicines at end of studyversus none of the control group. Diastolic blood pressure (DBP), triglycerides and LDL-C decreased significantly while HDL-C levels showed significant rise after iron depletion. It can be concluded from the present study that iron depletion therapy is beneficial for improving the efficiency of glycemic control, DBP, and dyslipidemia in poorly controlled type 2 diabetics with iron over load.
文摘We report the case of a 7 years old girl with Juvenile Hemochromatosis, due to homozygous mutation of HJV, which had increased serum iron indices and liver iron overload in the absence of any clinical sign of disease. Oral iron chelation with low dose deferasirox showed good efficacy and no side effects. The oral iron chelator deferasirox could be a valid option for removing excess iron in early Juvenile Hemochromatosis.
基金Grant from the Association for the Study of Hemochromatosis and Iron Overload Disorders-ONLUS (P.T.), Monza
文摘AIM: To re-evaluate the diagnostic criteria of insulin resistance hepatic iron overload based on clinical, biochemical and histopathological findings. METHODS: We studied 81 patients with hepatic iron overload not explained by known genetic and acquired causes. The metabolic syndrome (MS) was defined according to ATPⅢ criteria. Iron overload was assessed by liver biopsy. Liver histology was evaluated by Ishak's score and iron accumulation by Deugnier's score; steatosis was diagnosed when present in ≥ 5% of hepatocytes. RESULTS: According to transferrin saturation levels, we observed significant differences in the amount of hepatic iron overload and iron distribution, as well as the number of metabolic abnormalities. Using Receiving Operating Curve analysis, we found that the presence of two components of the MS differentiatedtwo groups with a statistically significant different hepatic iron overload (P < 0.0001). Patients with ≥ 2 metabolic alterations and steatosis had lower amount of hepatic iron, lower transferrin saturation and higher sinusoidal iron than patients with < 2 MS components and absence of steatosis. CONCLUSION: In our patients, the presence of ≥ 2 alterations of the MS and hepatic steatosis was associated with a moderate form of iron overload with a prevalent sinusoidal distribution and a normal transferrin saturation, suggesting the existence of a peculiar pathogenetic mechanism of iron accumulation. These patients may have the typical dysmetabolic iron overload syndrome. By contrast, patients with transferrin saturation ≥ 60% had more severe iron overload, few or no metabolic abnormalities and a hemochromatosis-like pattern of iron overload.
文摘Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are promising effective iron chelators for the treatment of iron overload in b-thalassemia patients;nonetheless, their side effects have also been reported. 3-Hydroxypyridinone derivatives are being developed as a safer new chelator and in combined chelation therapy. We evaluated the iron-chelating activity of 1-(N-acetyl-6-aminohexyl)-3-hydroxypyridin-4-one (CM1) in iron-loaded C57BL6 mice. The feeding of a ferrocene-supplemented diet (Fe diet) to mice resulted in iron overload, detectable plasma nontransferrin-bound iron (NTBI) and labile plasma iron (LPI), and increases of red cell membrane iron, plasma malondialdehyde (MDA) and excessive tissue iron deposits. Like DFP, the CM1 lowered the levels of the membrane non-heme iron, the NTBI and LPI (p < 0.05) and the MDA after 3 months of treatment. Administration of the Fe diet and the Fe diet along with the chelators did not change the morphology of the liver and heart. Numerous iron accumulations were observed in the liver and spleen tissues of the Fe dietfed mice, whereas the CM1 reduced such iron deposition. Thus, 1-(N-acetyl-6-aminohexyl)-3-hydro- xypyridin-4-one (CM1) can be considered a candidate bidentate oral iron chelator and is effective in the removal of toxic irons in blood compartment and tissues. The effectiveness and toxicity of the CM1 need to be investigated extensively in thalassemia mice and patients with iron overload.
文摘Iron overload is a condition involving excessive iron deposit in various organs,the liver being the main target organ for iron deposition and overload which are associated with significant liver morbidity and mortality.Iron overload can be categorized into primary and secondary causes.Primary iron overload,so-called hereditary hemochromatosis,is a wellrecognized disease with available standard treatment recommendations.However,secondary iron overload is a more diverse disease with many unclear areas to be explored.Secondary iron overload is more prevalent than primary iron overload and occurs as a consequence of various causes which differ significantly across geographic regions.The main causes of secondary iron overload are iron-loading anemias,and chronic liver disease.The liver-related outcomes,patient outcomes,and treatment recommendations in these patients differ depending on the cause of iron overload.This review summarizes the causes,pathophysiology,liver-related outcomes,disease outcomes,and treatments of secondary iron overload.