• Title, Summary, Keyword: iron overload

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Changes in Cytochrome c Oxidase and NO in Rat Lung Mitochondria Following Iron Overload

  • Kim, Min-Sun;Hong, Min-A;Song, Eun-Sook
    • Animal cells and systems
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    • v.13 no.2
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    • pp.105-112
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    • 2009
  • In this study, the effects of iron on cytochrome c oxidase (CcO) in rat lung mitochondria were examined. Similar to liver mitochondria, iron accumulated considerably in lung mitochondria (more than 2-fold). Likewise, the reactive oxygen species and nitric oxide (NO) content of mitochondria were increased by more than 50% and 100%, respectively. NO might be produced by nitric oxide synthase (NOS), eNOS and iNOS type, with particular contribution by NOS in mitochondria. The respiratory control ratio of iron overloaded lung mitochondria dropped to nearly 50% due to increased state 4. Likewise, cytochrome c oxidase activity was lowered significantly to approximately 50% due to excess iron. Real-time PCR revealed that the expression of isoforms 1 and 2 of subunit IV of CeO was enhanced greatly under excess iron conditions. Taken together, these results show that oxidative phosphorylation within lung mitochondria may be influenced by iron overload through changes in cytochrome c oxidase and NO.

Relationship between liver iron concentration determined by R2-MRI, serum ferritin, and liver enzymes in patients with thalassemia intermedia

  • Al-Momen, Hayder;Jasim, Shaymaa Kadhim;Hassan, Qays Ahmed;Ali, Hayder Hussein
    • BLOOD RESEARCH
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    • v.53 no.4
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    • pp.314-319
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    • 2018
  • Background Iron overload is a risk factor affecting all patients with thalassemia intermedia (TI). We aimed to determine whether there is a relationship of serum ferritin (SF) and alanine aminotransferase (ALT) with liver iron concentration (LIC) determined by R2 magnetic resonance imaging (R2-MRI), to estimate the most relevant degree of iron overload and best time to chelate in patients with TI. Methods In this cross-sectional study, 119 patients with TI (mean age years) were randomly selected and compared with 120 patients who had a diagnosis of thalassemia major (TM). Correlations of LIC, as determined by R2-MRI, with SF and ALT levels, were assessed in all participants. A P-value <0.05 was considered statistically significant. Results SF and LIC levels were lower in patients with TI than in those with TM; only ferritin values were significant. We found a statistically significant relationship between SF and LIC, with cut-off estimates of SF in patients with TI who had splenectomy and those who entered puberty spontaneously (916 and 940 ng/mL, respectively) with LIC >5 mg Fe/g dry weight (P<0.0001). A significant relationship was also found for patients with TI who had elevated ALT level (63.5 U/L), of 3.15 times the upper normal laboratory limit, using a cut-off for LIC ${\geq}5mg\;Fe/g\;dry\;weight$. Conclusion We determined the cut-off values for ALT and SF indicating the best time to start iron chelation therapy in patients with TI, and found significant correlations among iron overload, SF, and ALT.

Causes of Hyperferritinemia and Red Blood Cell Transfusion (고페리틴혈증의 원인과 적혈구 수혈)

  • Kim, Mi Seon;Kim, Sun Hyung
    • The Korean Journal of Blood Transfusion
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    • v.29 no.3
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    • pp.273-281
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    • 2018
  • Background: Ferritin is used to detect iron overload in patients with chronic red blood cell transfusions. Although ferritin reflects the amount of iron storage in the body, it may increase nonspecifically in inflammation and infection. This study analyzed the cause of increased ferritin and the association with a red blood cell (RBC) transfusion. Methods: The medical records of patients who visited the authors' hospital from January to December 2017 and underwent a ferritin test were reviewed retrospectively. Hyperferritinemia was defined as a ferritin level more than 1,000 ng/mL. The causes of hyperferritinemia were investigated by examining the laboratory findings and medical records. Results: The results revealed 417 cases of hyperferritinemia in 238 patients during the period. The most common diseases were hematologic malignancies from 125 cases (30.0%) in 31 patients and infectious diseases were the second most common. Iron overload was suspected in 119 cases in 33 patients, and 12 patients (76 cases) were transfused with more than 8 units of RBC for 1 year before the test. Conclusion: In hyperferritinemia, the rate of iron overload is high considering the underlying diseases and chronic RBC transfusion. To determine iron storage status accurately, it will be helpful to measure the C-reactive protein (CRP) and iron saturation in the ferritin test. Careful attention should be paid to habitual iron formulations and frequent transfusions due to the possibility of iron overload.

Temporal changes in mitochondrial activities of rat heart after a single injection of iron, including increased complex II activity

  • Kim, Mi-Sun;Song, Eun-Sook
    • Animal cells and systems
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    • v.14 no.2
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    • pp.91-98
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    • 2010
  • Male rats were given a single injection of iron, and temporal changes in iron content and iron-induced effects were examined in heart cellular fractions. Over a period of 72 h, the contents of total and labile iron, reactive oxygen species, and NO in tissue homogenate, nuclear debris, and postmitochondrial fractions were mostly constant, but in mitochondria they continuously increased. An abrupt decrease in membrane potential and NAD(P)H at 12 h was also found in mitochondria. The respiratory control ratio was reduced slowly with a slight recovery at 72 h, suggesting uncoupling by iron.While the ATP content of tissue homogenate decreased steadily until 72 h, it showed a prominent increase in mitochondria at 12 h. Total iron and calcium concentration also progressively increased in mitochondria over 72 h. Enzyme activity of the oxidative phosphorylation system was significantly altered by iron injection: activities of complexes I, III, and IV were reduced considerably, but complex II activity and the ATPase activity of complex V were enhanced. A reversal of activity in complexes I and II at 12 h suggested reverse electron transfer due to iron overload. These results support the argument that mitochondrial activities including oxidative phosphorylation are modulated by excessive iron.

Iron Toxicity to Peritoneal Macrophage Due to Alteration of Mitochondria by NO

  • Yoon, Ji-Yeon;Kim, Jin-Sun;Lee, Heum-Sook;Lee, Kyo-Young;Cheon, Choong-Ill;Lee, Myeong-Sok;Park, Jong-Hoon;Song, Eun-Sook
    • Animal cells and systems
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    • v.8 no.2
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    • pp.97-103
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    • 2004
  • The cytotoxic effect of iron was examined in peritoneal macrophage to determine contributing factors by iron injection to rat. Viability was reduced by 24% by the iron-overload and by 30% by short-term iron addition. Total iron was increased by 45% in the iron-overloaded with remarkable elevation (9 to 14 fold) in the presence of $FeSO_4$. Free calcium was also increased by 19% in control and 44% in iron-overloaded group due to additional $FeSO_4$ NO and MDA were increased by 40% and 136%, respectively, with significant reduction (37%) of NAD(P)H. RCR and cytochrome c oxidase activity were lowered approximately by 10% with reduction of mitochondrial membrane potential. Addition of iron was frequently associated with altered distribution of mitochondria of high membrane potential in the iron-overloaded macrophage. These results suggest altered mitochondria with high NO and low NAD(P)H due to iron.

Effect of iron overload with ascorbic acid on experimental colon carcinogenesis in mice

  • Ahn, Tae-Hyon;Kim, Sung-June;Jeong, Jae-Hwang;Nam, Sang Yoon;Yun, Young Won;Lee, Beom Jun
    • Journal of Biomedical and Translational Research
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    • v.18 no.4
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    • pp.136-141
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    • 2017
  • Excessive iron can promote the production of free radicals, thereby leading to harmful effects on cancer and aging. Ascorbic acid is not only an antioxidant but also a co-factor of iron absorption. The effect of iron-overload with ascorbic acid on experimental colon carcinogenesis was investigated in male ICR mice. Animals were treated weekly with azoxymethane (AOM, 10 mg/kg b.w.) at 0, 1, and 2 week and then drunk 2% dextran sodium sulfate (DSS)-containing water for the next 1 week. There were four experimental groups: carboxymethylcellulose (CMC) alone (control), CMC + ascorbic acid (AA), CMC + Fe, CMC + Fe + AA. The animals fed on AIN-76A purified rodent diet for six weeks. AA or $Fe_2O_3$ at the dose of 450 mg/kg b.w. were daily and orally treated for 6 weeks. The colonic mucosa was stained with methylene blue and then aberrant crypt foci (ACF) and polyps were counted. Thiobarbituric acid-reactive substances (TBARS) in serum and liver were determined. Iron concentration in liver was measured by inductively coupled plasma spectrophotometer. Fe-overload with AA strongly increased liver iron contents compared to control or Fe group (p<0.05). There were no significant differences in the number of ACF or polyps among all groups, although ironoverloaded groups had slightly higher numbers compared with the control or AA group. TBARS values in the liver were increased in the iron-overloaded groups compared to control and AA only group (p<0.05), but serum TBARS values were not changed. These results indicate that the excessive iron treatment did not affect the experimental colon carcinogenesis regardless of presence of AA in mice.

Transfusional Iron Overload and Choroid Plexus Hemosiderosis in a Pediatric Patient: Brain Magnetic Resonance Imaging Findings

  • Kim, Min Seon;Lee, Ha Young;Lim, Myung Kwan;Kang, Young Hye;Kim, Jun Ho;Lee, Kyung Hee
    • Investigative Magnetic Resonance Imaging
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    • v.23 no.4
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    • pp.390-394
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    • 2019
  • Hemosiderosis is characterized by the deposition of excess iron in body tissues. The choroid plexus is an important part of the central nervous system that can be the primary site of iron overload. T2*-weighted gradient echo (GRE) sequence provides high sensitivity for demonstrating cerebral microhemorrhagic foci and iron deposition. In the present study, we describe the case of a 15-year-old boy with acute lymphoblastic leukemia, in whom repeated transfusion led to iron accumulation in the brain. GRE sequence effectively demonstrated hemosiderin deposition in the choroid plexus.

Influence of Collagen and TGF-$\beta$I Gene Expression and Hepatic Fibrogenesis by Iron Overload in Rat (철 과잉투여가 흰쥐의 Hepatic Fibrogenesis와 Collagen 및 TGF-$\beta$I 유전자 발현에 미치는 영향)

  • 양영목;박종환;이현영;정연희;김해영
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.2
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    • pp.307-313
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    • 2001
  • Iron excess is known to affect long-term iron accumulation and tissue change such as fibrosis in liver. To determine the changes of expression level of genes associated with fibrosis by short-term iron exposure, we measured liver mRNA levels by reverse transcription polymerase chain reaction (RT-PCR) in rats fed dietary carbonyl iron (3%, wt/wt) for 9 weeks. The results showed that the expression of the collagen (I, III) and transforming growth factor (TGF)-$\beta$I mRNAs was enhanced in high-dose iron treated rat, compared to normal-dose iron treated rat. An electron microscopy study revealed that excess iron caused increase of collagen fibrils in liver. The cell shapes and compositions of hepatocytes and extracellular matrix(ECM) in liver were changed by the iron-treatment. Also, necrosised hepatocytes were broadly seen in ECM. Taken together, we suggest that iron overload affects changes of collagen and TGF-$\beta$I gene expression and these changes are associated with liver fibrogenesis.

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High Copy Rme1p Suppresses Iron-Induced Cell Growth Defect of Saccharomyces cerevisiae

  • Park, Yong-Sung;Yun, Cheol-Won;Kong, Jae-Yang;Kim, Tae-Hyoung;Sung, Ha-Chin
    • Journal of Microbiology and Biotechnology
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    • v.14 no.3
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    • pp.470-473
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    • 2004
  • In the yeast Saccharomyces cerevisiae, iron can be toxic. Because of this phenomenon, its metabolism of iron is strictly regulated. We have constructed a model system in which cell growth is defected during periods of iron over-load. When $Aft1-1^{up}$ protein was overexpressed with Ga110 promoter, a galactose inducible promoter, cell growth was defected and levels of CLN2 transcript decreased. However transcript levels of AFT1 and FET3 genes increased over time in a consistent manner throughout the course of $AFT1-1^{up}$ overexpression. We have screened to find genes to suppress cell growth defect by iron overload with YEp-derived high copy yeast genomic DNA library and found that high copy of Rmelp suppressed cell growth defects. Rme1p has been known as an activator protein of CLN2 gene expression. Taking these results together, we suggest that the yeast cell cycle is arrested at the $G_1$, phase by iron overload via Cln2p.

Effect of iron and selenium status on glutathione peroxidase activity and lipid peroxidation in rats

  • Lee, Beom-jun;Nam, Sang-yoon;Lee, Yong-soon;Park, Jae-hak
    • Korean Journal of Veterinary Research
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    • v.39 no.4
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    • pp.679-688
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    • 1999
  • The combined effects of iron and selenium status on glutathione peroxidase (GSHPx) activity, cytochrome P-450 activity, and lipid peroxidation in the liver and intestinal mucosa of rats were investigated. In experiment one, four experimental groups (+Se+Fe, -Se+Fe, +Se++Fe, -Se++Fe) were manipulated for 3 weeks with intramuscular administration of irondextran (++Fe) and/or normal diet (+Fe) and deionized water (-Se) and/or selenium-supplemented deionized water (+Se). In experiment two, 2% dietary carbonyl iron (instead of the parenteral administration) was fed for 3 weeks to rats. Body weight of rats was significantly decreased in both parenterally and orally iron-overloaded groups (p<0.01), regardless of Se supplement. Serum iron was significantly increased in parenterally iron-overloaded groups but it was marginally increased in orally iron-overloaded groups. There was no significant difference in hemoglobin content among experimental groups in either experiment one or two. Total iron in the small intestine, intestinal mucosa, and livers was significantly high in both parenterally and orally iron-overloaded rats, regardless of selenium status. In the liver and intestine, GSHPx activity was significantly higher in all selenium-supplemented groups, compared to Se-deficient groups (p<0.01) and lipid peroxidation was significantly enhanced in both parenterally and orally iron-overloaded groups, compared to iron-adequate groups. There was no significant difference in cytochrome P-450 activity in the livers between groups in both experiment one and two. These results indicated that GSHPx activity in liver and intestinal mucosa was depended on selenium status, regardless of iron status, and iron-overload enhances lipid peroxidation in liver and intestinal mucosa by increasing the tissue iron content.

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