The Battle for Iron between Humans and Microbes

2018 ◽  
Vol 25 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Peggy L. Carver

Background: Iron is an essential micronutrient for bacteria, fungi, and humans; as such, each has evolved specialized iron uptake systems to acquire iron from the extracellular environment. Objective: To describe complex ‘tug of war’ for iron that has evolved between human hosts and pathogenic microorganisms in the battle for this vital nutrient. Methods: A review of current literature was performed, to assess current approaches and controversies in iron therapy and chelation in humans. Results: In humans, sequestration (hiding) of iron from invading pathogens is often successful; however, many pathogens have evolved mechanisms to circumvent this approach. Conclusion: Clinically, controversy continues whether iron overload or administration of iron results in an increased risk of infection. The administration of iron chelating agents and siderophore- conjugate drugs to infected hosts seems a biologically plausible approach as adjunctive therapy in the treatment of infections caused by pathogens dependent on host iron supply (e.g. tuberculosis, malaria, and many bacterial and fungal pathogens); however, thus far, studies in humans have proved unsuccessful.

2021 ◽  
Author(s):  
Naheed Waseem A. Sheikh ◽  
Satish B. Kosalge ◽  
Tusharbindu R. Desai ◽  
Anil P. Dewani ◽  
Deepak S. Mohale ◽  
...  

Iron overload disease is a group of heterogeneous disease, which is caused either due to hereditary or acquired condition. Excess of iron participate in redox reactions that catalyzes the generation of reactive oxygen species (ROS) and increases oxidative stress, which causes cellular damage and encourage the cell injury and cell death. The electronic databases of Scopus, PubMed and Google Scholar have been intensively searched for the research as well as review articles published with the full text available and with the key words such as natural iron chelating agent, synthetic iron chelating agents, iron overload disease, oxidative stress and antioxidant which were appearing in the title, abstract or keywords. In light of the literature review presented in this artial, based on meta-analyses, we suggest that iron chelating agents were used for the management of iron overload disease. These agents were having wide spectrum of activity, they were not only used for the management of iron overload disease but also used as anticancer and antioxidant in various oxidative stress mediated diseases. Last from many years Desferoxamine (DFO) was used as standard iron chelator but currently two new synthetic iron chelators such as Deferiprone (DFP) and Deferasirox (DFS) are available clinically. These clinically available synthetic iron chelators were having serious side effects and certain limitations. Phytochemicals such as flavonoids and polyphenols compounds were having iron chelating as well as antioxidant property with no or minimal side effects. Hence, this review provides an updates on natural iron chelation therapy for the safe and efficacious management of iron overload diseases.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4031-4031
Author(s):  
Oscar Boutros Lahoud ◽  
Velta Willis ◽  
William B. Solomon

Abstract Background: Patients with beta-thalassemia intermedia are at increased risk of developing clinically relevant iron overload independent of blood transfusions, which can result in serious sequelae, including liver, myocardial and endocrine dysfunction. This is thought to be modulated by downregulation of hepcidin and upregulation of ferroportin1. Standard of care in these patients has essentially consisted of iron-chelating agents such as deferasirox, presumably based on the hypothesis that phlebotomy would worsen clinical anemia and potentially exacerbate further ineffective erythropoeisis2. We present the cases of two patients with non-transfusion dependent iron overload secondary to beta-thalassemia intermedia, who were treated with serial phlebotomies as well as hydroxyurea. Case #1: Patient A was heterozygous for the Gln39X beta zero thalassemic allele as well as heterozygous for the H63D HFE-1 allele, and presented with a serum ferritin of 1928 ng/ml. T2* MRI of liver and myocardium demonstrated mild iron deposition in the liver and none in the heart. During a period of 18 months Patient A received serial phlebotomies and hydroxyurea 500 mg daily with decrease in serum ferritin to 770 ng/ml with no change in her baseline Hb and an increase in Hb F from 7% to 15%. Repeat T2*MRI of the liver and myocardium demonstrated no clinically significant iron deposition. Patient A continues to be phlebotomized every one to two months. Case #2: Patient B was heterozygous for the Gln39X beta zero allele with no mutant HFE-1 alleles, and presented with a serum ferritin of 1230 ng/ml. T2* MRI of the liver and myocardium demonstrated iron deposition in the liver and none in the heart. Over a period of twelve months patient B received serial phlebotomies and hydroxyurea 500 mg daily with decrease in his serum ferritin to 450 ng/mL, with no change in baseline Hb and no increase in Hb F. Repeat T2* MRI demonstrated no cardiac iron overload and slight improvement in the liver T2* relaxation time. Patient B continues to be phlebotomized every one to two months. Discussion: We presented two cases of non-transfusion dependent iron overload secondary to beta thalassemia intermedia managed with the combination of phlebotomy and low dose hydroxyurea, which resulted in clinically significant decrease in serum ferritin. In both patients the decrease in serum ferritin averaged ~65 ng/ml/month. As a reference, the higher dose regimen of deferasirox 10 mg/kg/d has a reported average decrease in serum ferritin of around 222 ng/mL/year, corresponding to an estimated 18.5 ng/mL/month2. There was no change in either patient’s Hb/Hct or markers of ineffective erythropoiesis such as LDH, indirect bilirubin and reticulocyte count. This could be due to a somewhat protective effect from hydroxyurea, which may decrease unbound alpha-globin chains, thereby permitting phlebotomy while maintaining adequate counts. Conclusion: These two cases suggest that in some non-transfusion dependent patients, the combination of phlebotomy and hydroxyurea may be an appropriate first-line treatment of iron overload due to beta-thalassemia. It appears to potentially offer enhanced efficacy with presumably less toxicity than standard iron-chelating agents in selected patients. Further investigation is needed to determine the specific population that would benefit most from this combination. The optimal treatment modality/combination in those patients has yet to be determined. Additional studies about treatment effect on iron-regulatory pathways are warranted. References: (1) Gardenghi S, et al. Ineffective erythropoiesis in beta-thalassemia is characterized by increased iron absorption mediated by down-regulation of hepcidin and up-regulation of ferroportin. Blood 2007: 109(11):5027-5035. (2) Taher AT, et al. Deferasirox reduces iron overload significantly in nontransfusion-dependent thalassemia: 1-year results from a prospective, randomized, double-blind, placebo-controlled study. Blood 2012; 120(5): 970-977. Disclosures No relevant conflicts of interest to declare.


Hematology ◽  
2001 ◽  
Vol 2001 (1) ◽  
pp. 47-61 ◽  
Author(s):  
James P. Kushner ◽  
John P. Porter ◽  
Nancy F. Olivieri

Abstract Transfusion therapy for inherited anemias and acquired refractory anemias both improves the quality of life and prolongs survival. A consequence of chronic transfusion therapy is secondary iron overload, which adversely affects the function of the heart, the liver and other organs. This session will review the use of iron chelating agents in the management of transfusion-induced secondary iron overload. In Section I Dr. John Porter describes techniques for the administration of deferoxamine that exploit the pharmacokinetic properties of the drug and minimize potential toxic side effects. The experience with chelation therapy in patients with thalassemia and sickle cell disease will be reviewed and guidelines will be suggested for chelation therapy of chronically transfused adults with refractory anemias. In Section II Dr. Nancy Olivieri examines the clinical consequences of transfusion-induced secondary iron overload and suggests criteria useful in determining the optimal timing of the initiation of chelation therapy. Finally, Dr. Olivieri discusses the clinical trials evaluating orally administered iron chelators.


Author(s):  
Xiaomin Wang ◽  
Ye Li ◽  
Li Han ◽  
Jie Li ◽  
Cun Liu ◽  
...  

Iron overload, a high risk factor for many diseases, is seen in almost all human chronic and common diseases. Iron chelating agents are often used for treatment but, at present, most of these have a narrow scope of application, obvious side effects, and other disadvantages. Recent studies have shown that flavonoids can affect iron status, reduce iron deposition, and inhibit the lipid peroxidation process caused by iron overload. Therefore, flavonoids with iron chelating and antioxidant activities may become potential complementary therapies. In this study, we not only reviewed the research progress of iron overload and the regulation mechanism of flavonoids, but also studied the structural basis and potential mechanism of their function. In addition, the advantages and disadvantages of flavonoids as plant iron chelating agents are discussed to provide a foundation for the prevention and treatment of iron homeostasis disorders using flavonoids.


2008 ◽  
Vol 252 (10-11) ◽  
pp. 1225-1240 ◽  
Author(s):  
Guido Crisponi ◽  
Maurizio Remelli

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4527-4527
Author(s):  
Mauricette Michallet ◽  
Mohamad Sobh ◽  
Stéphane Morisset ◽  
Hélène Labussière-Wallet ◽  
Marie Y. Detrait ◽  
...  

Abstract Abstract 4527 The main objective of this study was to determine the impact of serum ferritin level on the different allogeneic HSCT outcomes in adult patients with hematological disorders in addition to other disease and patient variables. We evaluated the implication of iron overload in the HSCT mortality causes and the potential role of iron chelation. We included 158 patients, 100 males and 58 females with a median age of 45 years (18–67) who underwent allo-HSCT between 2002 and 2010. There were 83 AML, 10 CML (3CP, 2AP, 5BC), 11 MDS (10 acute phase; 1 CMML), 7 myeloproliferative disorders, 19 MM, 9 NHL, 6 HDG, 5 aplastic anemia and 3 hemoglobinopathies. Sixty-seven (42%) patients were sex mismatched (F→M:37; M→F:30); for ABO compatibility, 61% were compatible, 18% had minor incompatibility and 21% had major incompatibility. For CMV status, 36% were sero-negative, 15% were D+R-, 18% were D-R+ and 31% were D+R+. Concerning the HSCT procedures, 60 patients (38%) received PBSC and 98 (62%) received BM from 97 (61%) HLA related donors [matched, n=76; mismatched, n=21], and 61 (39%) HLA unrelated donors [matched, n=36; mismatched, n=25] after MAC [n=64, (41%)] or RIC [n=94, (59%)]. At transplantation, 91 (58%) were in CR or CP [CR1: n=61 (67%); ≥CR2: n=30 (33%)] and the rest of patients were in less that CR or CP [n=67 (42%)]. The median serum ferritin level at HSCT was 1327 microg./l (26–14136); 31(20%) patients had a level 26–500, 33 (21%) had a level 500–2500, and 94 (59%) >2500. There were no significant correlation between the different ferritin levels, disease kind and status at HSCT. Twenty two patients received iron chelating agents (Exjade, n=19; Desferal, n=3). After allo-HSCT, the cumulative incidence of acute GVHD ≥ II at 3 months was 14% (11–16.5) with 10.5% (8–13) for grade III and 7% (5–9) for grade IV; the 1 year cumulative incidence of limited and extensive chronic GVHD were 4% (2–6) and 12.4% (9–16) respectively. After a median follow-up of 18 months (1–106), the median OS was 25 months (16-NR) with a 2 years probability of 50% (43–59). The median PFS was 13.5 months (9–25) with a 2 years probability of 43% (34–50). The cumulative incidence of relapse at 1 year was 31% (27–34), the TRM rate was 6.5% (4.5–8.5) and 20% (17–23.5) at 3 months and 1 year respectively. We performed a multivariate analysis taking into account the patient age, gender, diagnosis, disease status a allo-HSCT, matching variables (sex, ABO, HLA, CMV), conditioning/HSC source and the different serum ferritin levels; the different results are shown in table1. Interestingly, we found that ferritin level >500 has a significant impact on OS which is explained by a significant higher TRM for patients with level >2500 and a significant mortality after relapse in patients with level 500–2500 (figure). The analysis on effect of iron chelating agents is ongoing and results will be communicated later. Serum ferritin level has been previously shown to impact on allo-HSCT survival without a clear explanation of its implication and at which level; in our study, we demonstrated that this survival difference is caused in part by higher TRM and the other part by mortality after relapse. In conclusion, we should give a better attention to iron overload, confer an efficient follow-up of this parameter and provide a treatment strategy after allo-HSCT especially when its level reaches 500μg/l at transplantation. Disclosures: Nicolini: Novartis, Bristol Myers-Squibb, Pfizer, ARIAD, and Teva: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.


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