Iron Overload Group Research Articles

DNA methylation plays an important role in iron-overloaded Tibetans.

The prevalence of iron overload in Tibetans in Tibet is higher than that in Han. DNA methylation (DNAm) is closely related to iron metabolism and iron level. Nevertheless, the epigenetic status of Tibetans with iron overload is unknown, and we therefore aimed to explore whether the phenomenon observed in the Tibetan population is regulated by epigenetics. The results showed that 2.26% of cytosine was methylated in the whole genome, and that the rate of CG cytosine methylation was higher in individuals in the iron overload (TH) group than in those in the iron normal (TL) group. We analyzed differentially methylated genes (DMGs) in whole-genome bisulfite sequencing data from the TH and TL groups of high-altitude Tibetans. Protein-protein interaction and pathway analyses of candidate DMGs related to iron uptake and transport showed that epigenetic changes in 10 candidate genes (ACO1, CYBRD1, FLVCR1, HFE, HMOX2, IREB2, NEDD8, SLC11A2, SLC40A1 and TFRC) are likely to relate to iron overload. This work reveals, for the first time, changes of DNAm in Tibetan people with iron overload, which suggest that DNAm is a mechanism underlying differences in iron content between individuals in the high-altitude Tibetan population. Our findings should contribute to the study of iron metabolism and the overall health status of Tibetans.

Comparison Between Hesperidin, Coumarin, and Deferoxamine Iron Chelation and Antioxidant Activity Against Excessive Iron in the Iron Overloaded Mice.

ObjectiveIron accumulation in the brain leads to the development of Alzheimer’s and Parkinson’s diseases. Nowadays, iron chelation therapy is the best way to decrease the side effects of iron and amyloid plaques accumulation. Iron chelators are commonly used for the treatment of Alzheimer’s disease. Previous studies have shown that natural products such as phenol and flavonoid compounds could chelate heavy metals. In the current study, we examined the iron chelation activity of hesperidin and coumarin on the brain tissue of iron-overloaded mice.Methods48 NMRI male mice were divided into eight groups (n = 6). Six groups were treated with iron dextran (100 mg/kg/day) four times a week for 6 weeks. After stopping the injections for a month, five groups of iron-overloaded mice were treated with hesperidin, coumarin, and desferal four times a week subsequent for four subsequent weeks. Finally, the mice were anesthetized, and blood samples were collected from the ventricle of the heart for subsequent examination. The brain tissues were isolated and fixed in the 4% paraformaldehyde solution for Perl’s staining.ResultsThe results show that hesperidin and coumarin could strongly chelate excessive iron from the serum and deposit iron from the brain tissue compared to desferal group. Catalase and super oxidase activity were decreased in the iron-overloaded group, but in the treated group by hesperidin and coumarin, the enzyme’s activity was increased significantly.ConclusionHesperidin and coumarin, as natural products, are powerful options to chelate iron ions and increase the activity of antioxidant enzymes.

Effects of Curcumin on Iron Overload in Rats

Background: Iron overload, common in patients with hematological disorders, is a key target in drug development. This study investigated the effects of curcumin on iron overload in rats.
 Methods: Forty male Wistar rats weighing 139.78 ± 11.95 gm (Mean ± SD) were divided into three equal groups: (i) controls; (ii) iron overload group that received six doses of iron dextran 1000 mg/kg–1 by intraperitoneal injections (i.p.); and (iii) iron overload curcumin group that received six doses of curcumin (1000 mg/kg BW by i.p.). In addition to six doses of iron dextran 1000 mg/kg–1 by i.p., we studied the effects of curcumin on liver function enzymes (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]); antioxidant enzymes (malondialdehyde [MDA], total oxidant status [TOS], total antioxidant status [TAS]); hematological parameters (hemoglobin [Hb], hematocrit [Hct], red blood cells [RBC], white blood cells [WBC], mean corpus volume [MCV], mean corpuscular hemoglobin [MCH], mean corpuscular hemoglobin concentration [MCHC]); and iron parameters (serum iron profile, transferrin, total iron-binding capacity [TIBC], ferritin, and transferrin saturation [TS%]).
 Results: Curcumin caused a significant decrease in the Hct and Hb concentrations in Group III (P < 0.05). It also significantly reduced the serum levels of ALT (52.45 ± 4.51 vs 89.58 ± 4.65 U/L) and AST (148.03 ± 6.47 vs 265.27 ± 13.02 U/L) at the end of the study (P < 0.05). The TIBC, transferrin levels, and TS significantly decreased when the rats were administered curcumin serum iron (P < 0.05). The TAS level significantly increased in Group III in comparison to Group I (the control group) (P < 0.05). At the end of the study, curcumin significantly reduced the serum levels of TOS (12.03 ± 2.8 vs 16.95 ± 5.05 mmol H2O2/L) while the TAS (1.98 ± 0.42 vs 1.06 ± 0.33 mmol Trolox equiv./L) was increased.
 Conclusion: The findings of the present study suggest the therapeutic potential of curcumin against iron overload.

Clinical Impact of Iron Overload on Morbidity in Patients with Sickle Cell Disease

▪Background:Donor erythrocyte (RBC) transfusion was the first therapy used in sickle cell disease (SCD) that targets the pathophysiology of sickle cell disease.1 Transfused RBCs represent iron that circumvents the normal pathways of iron regulation, this excess iron accumulates in tissues.2 Iron overload was present in one third of 141 adult SCD patients at post mortem (mean age, 36 years) and 7% of deaths were related to iron overload.3 In a cohort of 387 young adults from Atlanta, there were 22 deaths, 45% related to iron overload (cirrhosis: 9, heart failure: 2).4 The frequency of hospital admission increased with increased serum ferritin in 199 transfused SCD patients, although the extent to which iron overload was a cause or a consequence of disease severity was not clear.5 We designed a study to retrospectively review the clinical course of SCD patients with iron overload compared to those without iron overload.Methods:We retrospectively reviewed 105 patients at the sickle cell comprehensive clinic at the study institution from Jan 1, 1998 to Oct 31, 2016. Patients with Hb SS, HSC and HB S beta0thalassemia were included. Iron overload was defined as mean serum ferritin >1000 ng/ml and/or T2 liver MRI with hepatic iron content >3 mg/g dry weight. Clinical outcomes studied as categorical variables were liver disease - defined as hepatomegaly, coagulopathy, signs of portal HTN or cirrhosis, thyroid disease - symptoms or abnormal thyroid functions, hypogonadism - history or laboratory measurement of gonadotrophins, arthropathy - symptoms or radiological evidence of joint disease and congestive heart failure - symptoms or low left ventricular ejection fraction on echocardiogram. Clinical outcomes that were studied as continuous variables were number of hospitalization during study period and mean body mass index. Patients who were on chelation at any time were analyzed separately as a subgroup within the iron overload cohort. The categorical variables were analyzed by using Chi-Square test and numerical variable was analyzed using t-test for equality of means.Results:86 out of 105 patients had complete data for clinical outcomes. Out of 33 patients with iron overload 22 had liver disease (66.7%) as compared to only 20 out of 53 (37.7%) without iron overload (p-value =0.009 which was significant). Out of 31 patients with iron overload only 2 (6.5%) had thyroid disease as compared to 0 out of 53 patients (0%) without iron overload. Out of 30 patients with iron overload 0 (0%) had hypogonadism as compared to 3 out of 50 patients (6%) without iron overload. 5 out of 33 patients with iron overload (15.2%) had arthropathy as compared to 5 out of 53 without iron overload (9.4%). 4 out of 31 patients with iron overload had congestive heart failure (12.9%) compared to 3 out of 50 patients without iron overload (6.0%).A total of 10 out of 33 patients (30.3%) with iron overload got chelation at some time during the study period. 8 out of 10 patients (80%) with iron overload who got chelation had liver disease compared to 14 out of 23 patients (60%) with iron overload and no chelation. 2 out 10 patients (20%) who got chelation had thyroid disease compared to 0 out of 21 (0%) without chelation. Interestingly, 4 out of 10 patients (40%) who got chelation had arthropathy compared to 1 out of 23 (4.3%) without chelation (p-value = 0.021 which was significant). 3 out of 9 patients (33.3%) who got chelation had congestive heart failure compared to 1 out of 22 patients (4.5%) without chelation.The mean number of hospitalizations in the iron overload group was 32.07 vs 21.74 in the non-iron overload group during the study period (p-value = 0.169). The mean BMI was 24.59 in the iron overload group compared to 28.48 in the non-iron overload group (p-value = 0.021 was significant).Conclusion:Iron overload was associated with significantly more incidence of liver disease in SCD patients. Chelation was not associated with a statistical significant difference on the incidence of liver disease in the iron overload cohort. There was no significant differences observed in congestive heart failure, hypogonadism or arthropathy. However, patients who were chelated did have a significantly higher incidence of arthropathy. There was no statistically significant difference in the number of hospitalization. Patients with iron overload did have a statistical significant association with having lower BMI. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Salvia miltiorrhiza (SM) Injection Ameliorates Iron Overload-Associated Cardiac Dysfunction by Regulating the Expression of DMT1, TfR1, and FP1 in Rats.

Previous studies have found that Salvia miltiorrhiza (SM) injection have a protective effect on the iron overloaded (IO) heart. However, the mechanisms are not completely known. In the present study, we investigated the underlying mechanisms based on the iron transport-related proteins. The rats were randomly divided into five groups: control, IO group, low-dose SM group, high-dose SM group, and deferoxamine control group. Iron dextran was injected to establish the IO model. After 14 days of treatment, cardiac histological changes were observed by hematoxylin and eosin (H&E) staining. Iron uptake-related proteins divalent metal transporter-1 (DMT-1), transferrin receptor-1 (TfR-1), and iron export-related proteins ferroportin1 (FP1) in the heart were detected by Western blotting. The results showed that SM injection decreased cardiac iron deposition, ameliorated cardiac function, and inhibited cardiac oxidation. Most important of all, SM injection downregulated the expression of DMT-1 and TfR-1 and upregulated FP1 protein levels compared with the IO group. Our results indicated that reducing cardiac iron uptake and increasing iron excretion may be one of the important mechanisms of SM injection reducing cardiac iron deposition and improving cardiac function under the conditions of IO.

The protective mechanism of resveratrol against hepatic injury induced by iron overload in mice

Excessive iron deposition can produce toxicity. Liver, as the main storage site of iron, is more vulnerable to excessive iron than other organs. Many studies have found that Resveratrol (RES) can effectively eliminate oxygen free radicals and resist lipid peroxide damage. However, studies investigating the mechanism of how RES prevents liver injury induced by iron overload are few. This study aims to observe the protective effect of RES on liver injury induced by iron overload in mice. Mice, except for the control group, received an intraperitoneal injection of iron dextran (50 mg/kg) every morning. The L-RES and H-RES groups received intragastric administration of low- and high-concentration RES solutions (20 or 50 mg/kg). The deferoxamine (DFO) group was intraperitoneally injected with DFO (50 mg/kg), while the control and iron overload groups were intraperitoneally injected with the same amount of normal saline every afternoon. Two weeks after continuous administration, iron-overloaded mice treated with high and low doses of RES significantly improved liver injury (GOT and GPT) and decreased LDH activity and MDA content and increased SOD and GSH activities (P < 0.01). Morphological tests showed that RES treatment can reduce liver iron deposition and improve liver pathological changes in iron-overloaded mice. Furthermore, RES treatment caused a significant decrease in Ft expression (P < 0.01). In conclusion, RES can alleviate liver injury in iron-overloaded mice. The mechanism may be related to improve the antioxidant capacity and reduce excess iron in the liver.

Coaction of hepatic thioredoxin and glutathione systems in iron overload-induced oxidative stress.

In the present study, we demonstrate the coaction of thioredoxin and glutathione (GSH) systems in mouse liver against iron overload-induced oxidative stress (OS). Mice were injected intraperitoneally with an iron dextran solution twice a week for 3 weeks. Iron accumulation in mouse liver was demonstrated spectroscopically. To confirm the iron overload model in the liver, the increased gene expression levels of hepcidin (Hamp), ferroportin (Fpn1), and ferritin (Fth1), which regulate iron trafficking, were observed by a quantitative polymerase chain reaction. In the case of iron overload, the GSHlevel and the reduced glutathione/oxidized glutathioneratio, which represents a marker of OS, decreased significantly. An increase in the malondialdehyde level, one of the final products of the lipid peroxidation process, was observed. The gene expression of the thioredoxin system, including thioredoxin (Trx1) and thioredoxin reductase (TrxR1), was examined. ThoughTrxR1 expression decreased, no changes were observed in Trx1. The enzyme activity and semiquantitative protein expression of TRXR1 increased. The activity of GSHreductase and GSH peroxidase increased in the iron overload group. The gene and protein expressions of thioredoxininteracting protein, which is an indicator of the commitment of the cell to apoptosis, were elevated significantly. The increased protein expression of Bcl-2-related X protein and CASPASE-3, which is an indicator of apoptosis, increased significantly. In conclusion, excess iron accumulation in mouse liver tissue causes OS, which affects the redox state of the thioredoxin and GSH systems, inducing cell apoptosis and also ferroptosis due to increased lipid peroxidation and the depletion of GSH level.

Impact of iron overload by transfusion on survival and leukemia transformation of myelodysplastic syndromes in a single center of China

ABSTRACT Introduction Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases which are prone to progress into acute myeloid leukemia (AML). Iron overload (IOL) caused by transfusion occurred in most MDS patients. But how IOL influences MDS progression has not been clarified yet. Methods Herein, we collected clinical data from 143 MDS patients to investigate the impacts of IOL on patients survival and AML transformation. Results We found that median survival time, 3-year survival rate, leukemia-free survival (LFS) time were significantly shorter in patients with IOL than those with non-iron overload (NIOL) (P = 0.040; P = 0.044; P = 0.037). Besides, IOL was more likely to be found in higher-risk subgroups (assessed by IPSS and WPSS) of MDS patients which also promoted 2-year AML transformation. Furthermore, the serum ferritin (SF) was significantly correlated with the overall survival (OS) of MDS patients (r = −0.311, P < 0.05). The concentrations of both intracellular iron and reactive oxygen species (ROS) in CD34+ cells of bone marrow were higher in the IOL group than the NIOL group, respectively (P = 0.0426; P = 0.0185). Moreover, ROS level was closely correlated with the percentage of bone marrow blasts (r = 0.7200, P = 0.0370). Collectively, IOL threatened the survival of MDS patients and promoted AML transformation. Conclusion Elevated intracellular iron and ROS in CD34+ cells of bone marrow could accelerate the abnormal proliferation of blasts.

Effect of Ethanol Extract of Green Tea (Camellia Sinensis) to Lowering Iron Level in Ferrous Sulfate Induced Male Rats

Green tea (Camellia sinensis) has the potential to be developed as a natural agent for therapy of iron overload in thalassemia. The purpose of this research was to observe the ability of ethanol extract of green tea as a natural iron chelating agent in animal iron overload model. Ethanol extract of green tea leave (GTLE) was prepared by maceration using 70% ethanol. Sprague-Dawley male rats were divided into three groups (5 rats each), a normal control group (group I) received daily p.o. of deionized water, the iron overload group received 100 g/Kg BW (group II) of GTLE that given two hours before ferroussulfate0.5 g/Kg BW administrations and the last group (group III) received only 0.5 g/Kg BW of ferrous sulfate. GTLE and ferrous sulfate were given orally every day for 30 days. At the end of the experimental period, rat blood serum samples were collected. Iron content and alanine aminotransferase (ALT) levels were measured using a spectrophotometer followed by observing the histologic preparation of rat liver organ. The results showed that administration of green tea leaves ethanolic extract of 100 g/Kg BW was able to keep down iron and ALT levels in the rat blood to a normal level.

The protective effect of the cardiac thioredoxin system on the heart in the case of iron overload in mice

BackgroundIron, which is essential for many vital biological processes, causes significant clinical pathologies in the case of its deficiency or excess. Cardiovascular protective pathways are activated by iron therapy. However, determining the appropriate iron concentration is essential to protect heart tissue from iron-induced oxidative stress. The thioredoxin system is one of the antioxidant systems that protect cells against oxidative stress. Moreover, it allows the binding of many transcription factors for apoptosis, myocardial protection, the stimulation of cell proliferation, and angiogenesis processes, especially the regulation of the cardiovascular system. This study’s goal was to understand how iron overload affects the gene and protein levels of the thioredoxin system in the mouse heart. MethodsBALB/c mice were randomly separated into two groups. The iron overload group was administered with intraperitoneal injections of an iron-dextran solution twice a week for three weeks. In parallel, the control group was intraperitoneally given Dextran 5 solution. The total iron content, the total GSH level, the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, and thioredoxin reductase 1 (TXNRD1) activity were demonstrated spectroscopically. Changes in the iron metabolism marker genes and thioredoxin system genes were examined by qPCR. The quantitative protein expression of TXNRD1 and thioredoxin-interacting protein (TXNIP) was examined by western blotting. ResultsThe iron content of the heart increased in the iron overload group. The expression of hepcidin (Hamp) and ferroportin (Fpn) increased with iron overload. However, decreased expression was observed for ferritin (Fth). No changes were revealed in the GSH level and GSH/GSSG ratio. The gene expression of thioredoxin 1 (Txn1), Txnrd1, and Txnip did not change. TXNRD1 activity and protein expression increased significantly, while the protein expression of TXNIP decreased significantly. ConclusionIn the case of iron overload, the cardiac thioredoxin system is affected by the protein level rather than the gene level. The amount and duration of iron overload used in this study may be considered as a starting point for further studies to determine appropriate conditions for the iron therapy of cardiovascular diseases.

Phytic Acid Protects from Oxidative Stress Induced by Iron-Overload and High-Fat Diets in ß2-Microglobulin Knockout Mice.

The objective of this study was to examine the protective effect of phytic acid (PA) in reducing oxidative stress in an animal model for human hereditary hemochromatosis (HH) fed high-fat diets. Sixty-four ß2 microglobulin knockout (β2m KO) mice were randomly assigned to three treatments by feeding: control (basal), atherogenic (AT), and polyunsaturated fatty acid (PUFA) diets. One-half of the mice in each treatment group were fed 2% (wt/wt) PA. The ß2m+/+ mice (wild type (WT)) were fed a basal diet. All seven groups were fed for 10 weeks with a 50-ppm iron-containing diet (AIN-93G). Free iron and lipids were measured in serum samples. Nonheme iron, thiobarbituric acid-reactive substances (TBARS), superoxide dismutase (SOD), and catalase concentrations were measured in the liver tissue. Nonheme iron concentration in ß2m KO mice (on the basal diet) was 20× higher (p < 0.0001) than in the WT mice. Compared to the WT mice, ß2m KO mice had a significantly higher concentration of free iron in the serum (p < 0.0001), six-fold higher hepatic TBARs (p < 0.0001), and 18% lower hepatic SOD level. When PA was added to the β2m KO basal diet, a reduction (26 to 50%) of iron concentration was seen in the liver and heart. The addition of PA also significantly reduced TBARs in all three dietary groups of the iron-overloaded group, but most effectively in the control group. An increase in SOD concentration was seen only in the PUFA group, but serum triacylglycerol (TG) concentration was reduced in both dietary fat groups. In conclusion, our results suggest that PA protects against oxidative stress-induced by genetic iron overload alone or when fed high fat.

Abnormal Ferroptosis in Myelodysplastic Syndrome.

BackgroundFerroptosis is a form of iron-dependent non-apoptotic cell death, with characteristics of loss of the activity of the lipid repair enzyme, glutathione (GSH) peroxidase 4 (GPX4), and accumulation of lethal reactive lipid oxygen species. The mechanism of ferroptosis in myelodysplastic syndrome (MDS) is unclear.MethodsCell viability assay, reactive oxygen species (ROS) assay, GSH assay, and GPX activity assay were performed to study the regulation of ferroptosis in MDS cells obtained from MDS patients, the iron overload model mice, and cell lines.ResultsThe growth-inhibitory effect of decitabine could be partially reversed by ferrostatin-1 and iron-chelating agent [desferrioxamine (DFO)] in MDS cell lines. Erastin could increase the cytotoxicity of decitabine on MDS cells. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in MDS cells upon treatment with decitabine, which could be reversed by ferrostatin-1. The concentration of hemoglobin in peripheral blood of iron overload mice was negatively correlated with intracellular Fe2+ level and ferritin concentration. Iron overload (IO) led to decreased viability of bone marrow mononuclear cells (BMMNCs), which was negatively correlated with intracellular Fe2+ level. Ferrostatin-1 partially reversed the decline of cell viability in IO groups. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in BMMNCs of IO mice. DFO could increase the level of GSH. Ferrostatin-1 and DFO could increase the GPX4 activity of BMMNCs in IO mice. Ferrostatin-1 could significantly reverse the growth-inhibitory effect of decitabine in MDS patients. Decitabine could significantly increase the ROS level in MDS groups, which could be inhibited by ferrostatin-1 or promoted by erastin. Ferrostatin-1 could significantly reverse the inhibitory effect of decitabine on GSH levels in MDS patients. Erastin combined with decitabine could further reduce the GSH level. Erastin could further decrease the activity of GPX4 compared with the decitabine group.ConclusionFerroptosis may account for the main mechanisms of how decitabine induced death of MDS cells. Decitabine-induced ROS raise leads to ferroptosis in MDS cells by decreasing GSH level and GPX4 activity.

Change of Hepcidin in Patients with Iron Overload at the Tibet Plateau

To explore the possible etiological factors of iron overload through detecting plasma hepcidin level of adult males at Tibet plateau. 81 Tibetan male adult patients hospitalized in our department during January 2017 - December 2018 were selected, and divided into iron overload group and non-iron overload group. The difference in serum ferritin, serum iron, total iron binding capacity, hemoglobin, HBSAg, ALT, AST, albumin, creatinine and hepcidin of patients in each group were tested. To analyze the differences between groups. The regression analysis was applied to analyze the relationship between laboratory index and hepcidin. The plasma hepcidin of iron overload group was significantly higher than that of the non-iron overload group [93.69 (65.57-133.92) ng/ml vs 63.93 (40.01-90.65) ng/ml] (P=0.005). And there was a positive correlation between plasma hepcidin and ferritin (β=0.03 ng/ml，95%CI 0.01-0.05) (P<0.01) and BMI (β=5.71 ng/ml，95%CI 0.54-10.88) (P<0.05）. Iron overload at Tibet plateau can not be attributed to hepcidin deficiency in Tibetan adult male patients. Iron metabolism disorders in Tibetan population may be associated with metabolic syndrome.

Iron overload regulate the cytokine of mesenchymal stromal cells through ROS/HIF-1α pathway in Myelodysplastic syndromes

Iron overload is a significant feature of myelodysplastic syndromes (MDS) patients due to ineffective hematopoiesis and transfusion dependence. Excess iron results in organ dysfunction through the generation of reactive oxygen species (ROS) which can cause oxidative stress even mutation. Mesenchymal stromal cells (MSCs) are responsible for supporting and regulating hematopoiesis, whether MSCs is involved in the pathogenesis of MDS still need further elucidation. Hypoxia-inducible factors-1 (HIF-1) is an integral signal of inflammation that has been shown to up-regulating in MDS patient. We found that MDS-derived MSC had disorganized clones and increased level of apoptosis (n = 53). Iron transportation-related gene, such as DMT1 and ZIP14, and ROS level were increased in iron overload-MDS-MSC (n = 23). HIF-1a, as a crucial part of HIF-1, was also elevated in iron overload-group and PHD2 involved in the degradation of HIF-1a was reduced. Furthermore, HIF-1 downstream cytokines such IL-6, IL-8, TGF-βand VEGF that were also involved in the pathogenesis of MDS were increased in IO-MDS-MSC. When treated with DFO and NAC for iron chelation and antioxidation, the level of HIF-1a and related cytokines could decrease. We conclude that iron overload regulates the cytokine of mesenchymal stromal cells through ROS/HIF-1α pathway in Myelodysplastic syndromes, result in dysfunction of MSC and damage of microenvironment that may be involved in the pathogenesis of MDS.

Effect Of Iron And Diazoxide On Muscle Strength Development, Oxidative Stress And Lipid Profile In Diabetic Rats

Diabetes is a global health problem. Oxidative stress plays an essential role in the development of complications, among the most frequent symptoms is muscle fatigue. Diabetes also contributes to a high cardiovascular risk attributed to dyslipidemia. Diazoxide (dzx) is a drug that acts on mitoKATP. Studies indicate that this drug improves the development of muscle strength; on the other hand, it is known that iron overload (IO) increases oxidative stress, while a reduction has a protective role. The objective was to evaluate the effect of iron and dzx on the development of muscle strength, oxidative stress, and lipid profile in diabetic rats. Male Wistar rats (250g) were used in eight groups: control, diabetics, IO, diabetic + IO, low iron, diabetic + low iron, dzx, diabetic + dzx. Soleus muscle and extensor digitorum longus (EDL) of an extremity were extracted to perform the muscle tension tests, and the other limb was used to obtain homogenates to measure lipid oxidation, glutathione levels and total reactive oxygen species (ROS). Finally, the serum was collected to measure lipid profile. Rats fed with a low iron diet and dzx administration improved muscle strength and fatigue took longer to appear. The groups fed with IO had reduced muscle strength development. Regarding the lipid peroxidation, the groups of diabetic rats fed with a low iron diet (0.34 nM/mg of protein) and dzx administration (0.033 nM/mg of protein) had the lower levels of lipid peroxidation. As for the glutathione levels, diabetic rats treated with dzx obtained the highest levels of reduced glutathione (1.65 μmol of GSH/mg of protein) and oxidized glutathione (GSSG) levels in diabetic rats with a low iron diet obtained the lowest values (0.82 μmol of GSH/mg of protein). Concerning total ROS levels, diabetic rats treated with dzx got the lowest levels (2.80 DCF*mg of protein). As for the lipid profile, diabetic rats treated with dzx obtained lower levels (ẋ =105 mg/dL). Very low‐density lipoprotein (VLDL) levels were high in the group of diabetic rats without treatment (ẋ=58.06 mg/dL), and the group of diabetics + dzx obtained similar levels to the control group (ẋ=21.1 mg/dL). Dzx acts as a mitoKATP opener, previous studies reported that the opening of these channels provokes a decrease in oxidative stress during fatigue and also activates the electron transport chain, which promotes a constant production of ATP, which is necessary for energy production and in this way the generation of muscular strength. On the other hand, iron plays an essential role in the formation of the hydroxyl radical, which is the most dangerous radical, this agrees with the results we obtained in the groups that had an IO. The higher levels of oxidative stress and muscular strength were lower in IO groups; however, the iron restriction had a protective effect on oxidative stress levels. Regarding the lipid profile, both dzx and low iron diets were shown to have a positive impact on the lipid profile by mechanisms that are not yet known.

Chronic Iron Overload Restrains the Benefits of Aerobic Exercise to the Vasculature.

Physical exercise is a well-recognized effective non-pharmacological therapy for cardiovascular diseases. However, because iron is essential element in many physiological processes including hemoglobin and myoglobin synthesis, thereby playing a role on oxygen transport, many athletes use iron supplement to improve physical performance. Regarding this, iron overload is associated with oxidative stress and damage to various systems, including cardiovascular. Thus, we aimed to identify the vascular effects of aerobic exercise in a rat model of iron overload. Male Wistar rats were treated with 100mg/kg/day iron-dextran, i.p., 5days a week for 4weeks, and then underwent aerobic exercise protocol on a treadmill at moderate intensity, 60min/day, 5days a week for 8weeks. Exercise reduced vasoconstrictor response of isolated aortic rings by increasing participation of nitric oxide (NO) and reducing oxidative stress, but these benefits to the vasculature were not observed in rats previously subjected to iron overload. The reduced vasoconstriction in the exercised group was reversed by incubation with superoxide dismutase (SOD) inhibitor, suggesting that increased SOD activity by exercise was lost in iron overload rats. Iron overload groups increased serum levels of iron, transferrin saturation, and iron deposition in the liver, gastrocnemius muscle, and aorta, and the catalase was overexpressed in the aorta probably as a compensatory mechanism to the increased oxidative stress. In conclusion, despite the known beneficial effects of aerobic exercise on vasculature, our results indicate that previous iron overload impeded the anticontractile effect mediated by increased NO bioavailability and endogenous antioxidant response due to exercise protocol.

Blockade of angiotensin AT1 receptors prevents arterial remodelling and stiffening in iron-overloaded rats.

Damage to the vasculature caused by chronic iron-overload in both humans and animal models, is characterized by endothelial dysfunction and reduced compliance. In vitro, blockade of the angiotensin II AT1 receptors reversed functional vascular changes induced by chronic iron-overload. In this study, the effect of chronic AT1 receptor blockade on aorta stiffening was assessed in iron-overloaded rats. Male Wistar rats were treated for 15 days with saline as control group, iron dextran 200 mg·kg-1 ·day-1 , 5 days a week (iron-overload group), losartan (20 mg·kg-1 ·day-1 in drinking water), and iron dextran plus losartan. Mechanical properties of the aorta were assessed in vivo. In vitro, aortic geometry and biochemical composition were assessed with morphometric and histological methods. Thoracoabdominal aortic pulse wave velocity (PWV) increased significantly, indicating a decrease in aortic compliance. Co-treatment with losartan prevented changes on PWV, β-index, and elastic modulus in iron-overloaded rats. This iron-related increase in PWV was not related to changes in aortic geometry and wall stress. but to increased elastic modulus/wall stress ratio, suggesting that a change in the composition of the wall was responsible for the stiffness. Losartan treatment also ameliorated the increase in aorta collagen content of the iron-overload group, without affecting circulating iron or vascular deposits. Losartan prevented the structural and functional indices of aortic stiffness in iron-overloaded rats, implying that inhibition of the renin-angiotensin system would limit the vascular remodelling in chronic iron-overload.

The corrected QT interval prolongation in adolescents with cardiac iron overload β-thalassemia major.

Iron-induced cardiomyopathy remains the leading cause of mortality in β-thalassemia major patients. The T2* magnetic resonance imaging (MRI) technique is the gold standard for iron load detection, yet it is expensive and not widely available especially in the developing countries. Some previous studies showed that QTc interval could be used as an early detection of cardiac iron overload. This study aimed to evaluate the diagnostic value of QTc interval as a marker of early detection of cardiac iron overload in adolescent beta thalassemia major patients. We prospectively evaluated electrocardiography (ECG) parameter of QTc interval in 50 β-thalassemia major patients aged 10-18 years. All participants had a 12-lead ECG evaluation, echocardiogram and cardiac MRI T2* examination within three months (average 15 days). They were categorized as cardiac iron overload (MRI T2* < 20 millisecond) and non-cardiac iron overload (MRI T2* > 20 millisecond). Of the 50 patients, the male to female ratio was 1.08:1 and the mean age was 13.7 ± 2.43 years. All participants showed normal systolic and diastolic function using conventional echocardiography. The mean QTc interval was significantly different between cardiac iron overload group (464.44 ± 20.35 ms) and noncardiac iron overload group (431.09 ± 32.29) (p= 0.001). Diagnostic study of QTc interval resulted in AUC 0.8 (p= 0.002). Calculated sensitivity and specificity of QTc interval were 0.88 and 0.73 respectively, with cut-off point of 449 ms. Cardiac iron overload is associated with QTc prolongation in adolescents. QTc interval of 449 ms could be considered as a cut-off point of cardiac iron overload.

Effect of iron chelation therapy on EPO-STAT5 signalling pathway and EPO resistance in iron-overloaded low-risk myelodysplastic syndrome patients

ABSTRACT Objectives: Background/aims: We aim to explore low-risk MDS patients’ ESA response and the difference between iron-overloaded (IO) group and the control group in the expression of SOCS1, STAT5 and BCL2L1 which play a key role to EPO-STAT5 signal pathway. Methods: 56 low-risk MDS patients were divided into experimental group, IO patients; control group, non-IO patients. Among experimental group, 28 IO patients were treated with iron chelation therapy (ICT). SOCS1, phosphorylated STAT5 (p-STAT5) and BCL2L1 protein concentration in bone marrow supernatant have been analyzed by ELISA, STAT5a+b protein concentration in bone marrow mononuclear cells (BMMC) have been analyzed by Western blot, and mRNA expression of them have been detected in BMMC by RQ-PCR. The percentage of CD71+ cells in BMMC, apoptotic rate of CD71+ cells and ROS expression in CD71+ cells were detected by Flow cytometry. Results: Compared with the control group, the sEPO concentration, the efficacy of ESA and the expression of SOCS1, apoptotic rates of CD71+ cells and ROS expression in CD71+ cells in IO group were increased, the expression of STAT5 and BCL2L1 was reduced. Interestingly, after receiving ICT, some patients with EPO resistance have responded again to ESA treatment, with the decrease of the expression of SOCS1, apoptotic rates of CD71+ cells, ROS expression in CD71+ cells and the increase of the expression of STAT5 and BCL2L1. Conclusion: Iron overload can increase EPO resistance and the expression of SOCS1, inhibit the expression of STAT5 and BCL2L1. ICT could allivation of EPO resistance.

Impact of Iron Overload and Iron Removal Therapy on Outcome of Allogeneic Hematopoietic Stem Cell Transplantation in the Patients with Severe Aplastic Anemia

Abstract:The aim of this study was to evaluate the Impact of iron overload and iron removal therapy on the outcome of allogeneic hematopoietic stem cell transplantation (SCT) in patients with severe aplastic anemia (SAA). Forty-five transplant patients with SAA were retrospectively analyzed. Patients were divided into two groups according to whether there was iron overload or not: iron overload group (n=23) and non-iron overload group (n=22). The iron overload group had higher 1-year transplant-related mortality (TRM) (30.4% vs. 4.5%, P = 0.02), lower 1-year transfusion-free survival (TFS) (40.6% vs. 81.8%, P = 0.007) and lower 1-year overall survival (OS) (54.8% vs. 90.2%, P = 0.003) than the non-iron overload group. However, there was no significant difference in implantation rate, pre-engraftment syndrome (PES) and acute graft-versus-host disease (aGVHD, grade III-IV) between the two groups. Furthermore, the multivariate analysis revealed that iron overload was an independent risk factor affecting OS (HR = 36.88, P = 0.03). The patients in iron overload group were divided into two subgroups according to the time of iron removal using deferasirox 20mg/kg/d. Specifically, group A (n=17) was treated with deferasirox 20mg/kg/d for 3 months or less and group B (n=6) treated for more than 3 months. The results showed that group B had a lower one-year TRM (0% vs. 41.2% , P = 0.07), higher 1-year TFS (66.7% vs. 31.4%, P = 0.18) and higher 1-year OS (100% vs. 31.4% , P = 0.02) than group A. There were no significant difference in implantation rate, PES and aGVHD ( III-IV) between the two groups. In conclusion, the results indicate that iron overload before transplantation was associated with increased TRM and decreased OS, suggesting that iron overload was associated with worse transplantation outcomes. However, standardized iron removal therapy could reverse the adverse effects of iron overload on the outcomes of transplantation to a certain extent and improve the prognosis significantly. Disclosures No relevant conflicts of interest to declare.