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1.
The role of iron in the pathogenesis of COVID-19 and possible treatment with lactoferrin and other iron chelators.
Habib, HM, Ibrahim, S, Zaim, A, Ibrahim, WH
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie. 2021;:111228
Abstract
Iron overload is increasingly implicated as a contributor to the pathogenesis of COVID-19. Indeed, several of the manifestations of COVID-19, such as inflammation, hypercoagulation, hyperferritinemia, and immune dysfunction are also reminiscent of iron overload. Although iron is essential for all living cells, free unbound iron, resulting from iron dysregulation and overload, is very reactive and potentially toxic due to its role in the generation of reactive oxygen species (ROS). ROS react with and damage cellular lipids, nucleic acids, and proteins, with consequent activation of either acute or chronic inflammatory processes implicated in multiple clinical conditions. Moreover, iron-catalyzed lipid damage exerts a direct causative effect on the newly discovered nonapoptotic cell death known as ferroptosis. Unlike apoptosis, ferroptosis is immunogenic and not only leads to amplified cell death but also promotes a series of reactions associated with inflammation. Iron chelators are generally safe and are proven to protect patients in clinical conditions characterized by iron overload. There is also an abundance of evidence that iron chelators possess antiviral activities. Furthermore, the naturally occurring iron chelator lactoferrin (Lf) exerts immunomodulatory as well as anti-inflammatory effects and can bind to several receptors used by coronaviruses thereby blocking their entry into host cells. Iron chelators may consequently be of high therapeutic value during the present COVID-19 pandemic.
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2.
Iron Chelators Dictate Immune Cells Inflammatory Ability: Potential Adjuvant Therapy for IBD.
Chieppa, M, Galleggiante, V, Serino, G, Massaro, M, Santino, A
Current pharmaceutical design. 2017;(16):2289-2298
Abstract
BACKGROUND The importance of hemoproteins for life lies largely in their iron-mediated chemical properties. In the human body, there are about 4 g of iron, a precious resource preserved by sophisticated recycling mechanisms. Iron is also important for pathogen growth, so it is not surprising that immune cells developed mechanisms to reduce iron availability in cases of inflammation. In healthy conditions, macrophages degrade hemoproteins and export iron, while if inflammation develops, they retain cytoplasmic iron to reduce extracellular iron concentrations. Iron-rich macrophages possess a stronger inflammatory ability, which explains the chronic inflammatory response observed in states of iron overload. Inflammatory bowel syndromes are often characterized by intestinal blood loss and consequent anemia, but iron-supplementation therapies may exacerbate the inflammatory response. In chronically transfused patients iron overload is frequently observed; the iron can become toxic and in excess, even fatal if not treated with iron-chelating drugs. CONCLUSION In the present review, we discuss the importance of iron homeostasis in states of health and inflammation, focusing on iron and iron-chelation treatment for IBD patients. Oral administration of natural ironchelating chemicals may be an effective adjuvant therapy for IBD patients, acting on numerous aspects of chronic inflammatory syndromes.
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3.
Novel immunosuppressive agent caerulomycin A exerts its effect by depleting cellular iron content.
Kaur, S, Srivastava, G, Sharma, AN, Jolly, RS
British journal of pharmacology. 2015;(9):2286-99
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Abstract
BACKGROUND AND PURPOSE Recently, we have described the use of caerulomycin A (CaeA) as a potent novel immunosuppressive agent. Immunosuppressive drugs are crucial for long-term graft survival following organ transplantation and treatment of autoimmune diseases, inflammatory disorders, hypersensitivity to allergens, etc. The objective of this study was to identify cellular targets of CaeA and decipher its mechanism of action. EXPERIMENTAL APPROACH Jurkat cells were treated with CaeA and cellular iron content, iron uptake/release, DNA content and deoxyribonucleoside triphosphate pool determined. Activation of MAPKs; expression level of transferrin receptor 1, ferritin and cell cycle control molecules; reactive oxygen species (ROS) and cell viability were measured using Western blotting, qRT-PCR or flow cytometry. KEY RESULTS CaeA caused intracellular iron depletion by reducing its uptake and increasing its release by cells. CaeA caused cell cycle arrest by (i) inhibiting ribonucleotide reductase (RNR) enzyme, which catalyses the rate-limiting step in the synthesis of DNA; (ii) stimulating MAPKs signalling transduction pathways that play an important role in cell growth, proliferation and differentiation; and (iii) by targeting cell cycle control molecules such as cyclin D1, cyclin-dependent kinase 4 and p21(CIP1/WAF1) . The effect of CaeA on cell proliferation was reversible. CONCLUSIONS AND IMPLICATIONS CaeA exerts its immunosuppressive effect by targeting iron. The effect is reversible, which makes CaeA an attractive candidate for development as a potent immunosuppressive drug, but also indicates that iron chelation can be used as a rationale approach to selectively suppress the immune system, because compared with normal cells, rapidly proliferating cells require a higher utilization of iron.
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The effect of iron loading and iron chelation on the innate immune response and subclinical organ injury during human endotoxemia: a randomized trial.
van Eijk, LT, Heemskerk, S, van der Pluijm, RW, van Wijk, SM, Peters, WH, van der Hoeven, JG, Kox, M, Swinkels, DW, Pickkers, P
Haematologica. 2014;(3):579-87
Abstract
In this double-blind randomized placebo-controlled trial involving 30 healthy male volunteers we investigated the acute effects of iron loading (single dose of 1.25 mg/kg iron sucrose) and iron chelation therapy (single dose of 30 mg/kg deferasirox) on iron parameters, oxidative stress, the innate immune response, and subclinical organ injury during experimental human endotoxemia. The administration of iron sucrose induced a profound increase in plasma malondialdehyde 1 h after administration (433±37% of baseline; P<0.0001), but did not potentiate the endotoxemia-induced increase in malondialdehyde, as was seen 3 h after endotoxin administration in the placebo group (P=0.34) and the iron chelation group (P=0.008). Endotoxemia resulted in an initial increase in serum iron levels and transferrin saturation that was accompanied by an increase in labile plasma iron, especially when transferrin saturation reached levels above 90%. Thereafter, serum iron decreased to 51.6±9.7% of baseline at T=8 h in the placebo group versus 84±15% and 60.4±8.9% of baseline at 24 h in the groups treated with iron sucrose and deferasirox, respectively. No significant differences in the endotoxemia-induced cytokine response (TNF-α, IL-6, IL-10 and IL-1RA), subclinical vascular injury and kidney injury were observed between groups. However, vascular reactivity to noradrenalin was impaired in the 6 subjects in whom labile plasma iron was elevated during endotoxemia as opposed to those in whom no labile plasma iron was detected (P=0.029). In conclusion, a single dose of iron sucrose does not affect the innate immune response in a model of experimental human endotoxemia, but may impair vascular reactivity when labile plasma iron is formed. (Clinicaltrials.gov identifier:01349699).
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Immunological evaluation of β-thalassemia major patients receiving oral iron chelator deferasirox.
Aleem, A, Shakoor, Z, Alsaleh, K, Algahtani, F, Iqbal, Z, Al-Momen, A
Journal of the College of Physicians and Surgeons--Pakistan : JCPSP. 2014;(7):467-71
Abstract
OBJECTIVE To determine the immune abnormalities and occurrence of infections in transfusion-dependent β-thalassemia major patients receiving oral iron chelator deferasirox (DFX). STUDY DESIGN An observational study. PLACE AND DURATION OF STUDY Hematology Clinics, King Khalid University Hospital, Riyadh, Saudi Arabia, from July to December 2010. METHODOLOGY Seventeen patients with β-thalassemia major (12 females, median age 26 years) receiving deferasirox (DFX) for a median duration of 27 months were observed for any infections and had their immune status determined. Immune parameters studied included serum immunoglobulins and IgG subclasses, serum complement (C3 and C4) and anti-nuclear antibody (ANA) level, total B and T-lymphocytes, CD4+ and CD8+ counts, CD4+/CD8+ ratio, and natural killer (NK) cells. Immunological parameters of the patients were compared with age, gender, serum ferritin level and splenectomy status. Lymphocyte subsets were also compared with age and gender matched normal controls. RESULTS A considerable reduction in serum ferritin was achieved by DFX from a median level of 2528 to 1875 μmol/l. Serum IgG levels were increased in 7 patients. Low C4 levels were found in 9 patients. Total B and T-lymphocytes were increased in 14 patients each, while CD4+, CD8+ and NK cells were increased in 13, 12 and 11 patients respectively. Absolute counts for all lymphocyte subsets were significantly higher compared to the normal controls (p ² 0.05 for all parameters). Raised levels of IgG were associated with older age, female gender, splenectomized status and higher serum ferritin levels but this did not reach statistical significance except for the higher ferritin levels (p=0.044). Increased tendency to infections was not observed. CONCLUSION Patients with β-thalassemia major receiving DFX exhibited significant immune abnormalities. Changes observed have been described previously, but could be related to DFX. The immune abnormalities were not associated with increased tendency to infections.
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Effect of supplementation with ferrous sulfate or iron bis-glycinate chelate on ferritin concentration in Mexican schoolchildren: a randomized controlled trial.
Duque, X, Martinez, H, Vilchis-Gil, J, Mendoza, E, Flores-Hernández, S, Morán, S, Navarro, F, Roque-Evangelista, V, Serrano, A, Mera, RM
Nutrition journal. 2014;:71
Abstract
BACKGROUND Iron deficiency is one of the most common nutritional deficiencies worldwide. It is more prevalent when iron requirements are increased during pregnancy and during growth spurts of infancy and adolescence. The last stage in the process of iron depletion is characterized by a decrease in hemoglobin concentration, resulting in iron deficiency anemia. Iron deficiency, even before it is clinically identified as anemia, compromises the immune response, physical capacity for work, and intellectual functions such as attention level. Therefore, interventions addressing iron deficiency should be based on prevention rather than on treatment of anemia. The aim of this study was to compare short- and medium-term effects on ferritin concentration of daily supplementation with ferrous sulfate or iron bis-glycinate chelate in schoolchildren with iron deficiency but without anemia. METHODS Two hundred schoolchildren from public boarding schools in Mexico City who had low iron stores as assessed by serum ferritin concentration but without anemia were randomly assigned to a daily supplement of 30 mg/day of elemental iron as ferrous sulfate or iron bis-glycinate chelate for 12 weeks. Iron status was evaluated at baseline, one week post-supplementation (short term), and 6 months (medium term) after supplementation. RESULTS Ferritin concentration increased significantly between baseline and post-supplementation as well as between baseline and 6 months after supplementation. One week post-supplementation no difference was found in ferritin concentration between iron compounds, but 6 months after supplementation ferritin concentration was higher in the group that received bis-glycinate chelate iron. However, there is no difference in the odds for low iron storage between 6 months after supplementation versus the odds after supplementation; nor were these odds different by type of supplement. Hemoglobin concentration did not change significantly in either group after supplementation. CONCLUSIONS Supplementing with 30 mg/d of elementary iron, either as ferrous sulfate or iron bis-glycinate chelate for 90 days, showed positive effects on increasing ferritin concentration in schoolchildren with low iron stores, and this effect persisted 6 months after supplementation.
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The effects of chelators on zinc levels in patients with thalassemia major.
Erdoğan, E, Canatan, D, Ormeci, AR, Vural, H, Aylak, F
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2013;(2):109-11
Abstract
Zinc which is an essential element has very important effects on growth and immune system in patients with thalassemia major (TM). The effects of two oral iron chelator agents, desferrioxamine (DFO) and deferiprone (DFP), on zinc levels were investigated in previous studies and they were found to cause zinc deficiency. Zinc level alteration by the new chelator deferasirox (DFX) is not present in the literature. The aim of this study was to examine the effects of different oral chelators on serum and urine zinc levels in TM patients. Zinc levels are compared in the patients who received different chelators: only DFX, combined chelation with DFO plus DFP and the healthy control group. A total of 56 patients with TM were involved in this study: 39 patients received only DFX and 17 patients were given combined treatment DFO+DFP between August 2008 and August 2009. In addition, a control group was established from the healthy population. Blood was taken from all the patients for serum zinc levels and 24hour-urine samples were collected for urine zinc levels. Serum zinc levels were found to be 64.8±14.8μg/dL in DFX group and 66.5±15.1μg/dL in DFO+DFP group. These levels were statistically lower than that in the control group (149±54.3μg/dL) (p<0.05), but there was no statistically difference between the two different chelation groups (p>0.05). The urine zinc levels of DFX and DFO+DFP group were 662.2±428.2μg/day and 1182.3±980.3μg/day respectively (p<0.05). Urinary zinc excretion in the chelation groups (DFX and DFO+DFP) was significantly higher than the control group (395.1±208.9μg/day) (p<0.05). As a conclusion, the new chelation agent, DFX, also leads to zinc deficiency, though its urinary zinc excretion is lower. New studies are required to examine the effects of DFX on zinc extensively. Zinc levels of patients with TM should be followed up regularly and zinc supply should be given at early ages.
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Idiosyncratic drug-induced agranulocytosis: the paradigm of deferiprone.
Pontikoglou, C, Papadaki, HA
Hemoglobin. 2010;(3):291-304
Abstract
Non chemotherapy drug-induced agranulocytosis is considered a potentially life-threatening idiosyncratic blood dyscrasia, thought to result from a partly elucidated immune and/or toxic damage on myelopoiesis, due to a multitude of drugs. Offending agents include clozapine, ticlopidine, antithyroid compounds, dipyrone, sulfasalzine, trimethropim/sulfomethoxazole, carmabazepine, and to a lesser extent, deferiprone (L1) and probably rituximab. Suspected drugs should be immediately stopped and, in symptomatic patients, once appropriate cultures have been obtained, broad-spectrum antibiotic treatment should be administered. Hematopoietic growth factors may be considered, specifically in patients with poor prognostic factors. Due to improved intensive care treatment and alertness of physicians the case fatality of the disorder has recently been decreased to 5%.
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Red blood cell transfusion therapy and iron chelation in patients with myelodysplastic syndromes.
Malcovati, L
Clinical lymphoma & myeloma. 2009;:S305-11
Abstract
Anemia is the most frequent peripheral cytopenia observed in myelodysplastic syndromes (MDS) and has been recognized among the most important factors affecting the outcome of patients with MDS. In patients who are not candidates for potentially curative approaches, therapeutic options for symptomatic anemia include red blood cell (RBC) transfusion and iron chelation, hematopoietic growth factors, immunosuppression, immune-modulatory drugs, and hypomethylating agents. In about 40% of patients, regular RBC transfusions are the only therapeutic option that can be offered. The onset of a regular transfusion requirement significantly worsens the survival of patients with MDS. Transfusion-dependent patients invariably develop secondary iron overload. Elevated serum ferritin was proven to be associated with worse survival in transfusion-dependent patients, and recent data obtained using magnetic resonance imaging show both hepatic and myocardial iron accumulation in heavily transfused patients. According to evidence-based guidelines, patients with sideroblastic anemia, 5q- syndrome, or other forms of refractory anemia, in whom long-term transfusion therapy is likely, are recognized as the best candidates to receive iron chelation therapy. In addition, patients who are candidates for allogeneic stem cell transplantation might also benefit from chelation therapy because iron overload is associated with increased transplantation-related mortality. RBC transfusions and iron chelation are the mainstay of therapy for many individuals with MDS. However, critical issues remain to be clarified in order to optimize treatment, including the identification of target hemoglobin levels to prevent anemia-related morbidity and more accurate information on the effect of iron-mediated organ damage on the outcome of patients with MDS.
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Desferoxamine (DFO)--mediated iron chelation: rationale for a novel approach to therapy for brain cancer.
Dayani, PN, Bishop, MC, Black, K, Zeltzer, PM
Journal of neuro-oncology. 2004;(3):367-77
Abstract
Iron homeostasis is crucial to normal cell metabolism, and its deficiency or excess is associated with numerous disease states. The association of increased iron load with cancer may be due to several factors including free radical production, reduction of the body's protective mechanism to combat oxidative stress, inhibition of immune systems, inhibition of essential nutrient functions, facilitation of cancer growth, suppression of antitumor actions of macrophages, and lowering of the ratio of T4-T8 positive lymphocytes. Antiproliferative effects of desferoxamine (DFO) both in vitro and in vivo are mediated by an intracellular pool of iron that is necessary for DNA synthesis rather than prevention of iron uptake from transferrin. Several clinical studies have shown it to have antitumor activity in the treatment of neuroblastoma, leukemia, bladder carcinoma, and hepatocellular carcinoma. Human neural tumor cells are susceptible to the effects of DFO. Continued study of DFO is necessary to further elucidate its antineoplastic profile and its use as an adjunct to current chemotherapy regimens. Given the lack of satisfactory treatment of central nervous system neoplasms, DFO could serve as an important tool in the management of such cancers.