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Blood Res 2019; 54(2):

Published online June 30, 2019

https://doi.org/10.5045/br.2019.54.2.87

© The Korean Society of Hematology

Role of redox iron towards an increase in mortality among patients: a systemic review and meta-analysis

Sankalp Sharma

Department of Transfusion Medicine and Blood Bank, All India Institute of Medical Sciences Raipur, Chhattisgarh, India

Correspondence to : Sankalp Sharma, M.D.
Department of Transfusion Medicine and Blood Bank, Gate Number 1, Hospital Block–A, G E Road, All India Institute of Medical Sciences, Raipur, Raipur Chhattisgarh, India
E-mail: sunray2077@gmail.com

Received: September 23, 2018; Revised: November 6, 2018; Accepted: November 6, 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An increase in biochemical concentrations of non-transferrin bound iron (NTBI) within the patients with an increase in serum iron concentration was evaluated with the following objectives: (a) Iron overloading diseases/conditions with free radicle form of ‘iron containing’ reactive oxygen species (ROS) and its imbalance mediated mortality, and (b) Intervention with iron containing drugs in context to increased redox iron concentration and treatment induced mortality. Literature search was done within Pubmed and cochrane review articles. The Redox iron levels are increased during dys-erythropoiesis and among transfusion recipient population and are responsive to iron-chelation therapy. Near expiry ‘stored blood units’ show a significant rise in the ROS level. Iron mediated ROS damage may be estimated by the serum antioxidant level, and show reduction in toxicity with high antioxidant, low pro-oxidant levels. Iron drug therapy causes a significant increase in NTBI and labile iron levels. Hospitalized patients on iron therapy however show a lower mortality rate. Serum ferritin is a mortality indicator among the high-dose iron therapy and transfusion dependent population. The cumulative difference of pre-chelation to post chelation ROS iron level was 0.97 (0.62; 1.32; N=261) among the transfusion dependent subjects and 2.89 (1.81–3.98; N=130) in the post iron therapy ‘iron ROS’ group. In conclusion, iron mediated mortality may not be mediated by redox iron among multi-transfused and iron overloaded patients.

Keywords Chelation antioxidants, Hepcidin, Non transferrin bound iron, Pro-oxidant effect, Serum ferritin, Transferrin saturation

Article

Review Article

Blood Res 2019; 54(2): 87-101

Published online June 30, 2019 https://doi.org/10.5045/br.2019.54.2.87

Copyright © The Korean Society of Hematology.

Role of redox iron towards an increase in mortality among patients: a systemic review and meta-analysis

Sankalp Sharma

Department of Transfusion Medicine and Blood Bank, All India Institute of Medical Sciences Raipur, Chhattisgarh, India

Correspondence to:Sankalp Sharma, M.D.
Department of Transfusion Medicine and Blood Bank, Gate Number 1, Hospital Block–A, G E Road, All India Institute of Medical Sciences, Raipur, Raipur Chhattisgarh, India
E-mail: sunray2077@gmail.com

Received: September 23, 2018; Revised: November 6, 2018; Accepted: November 6, 2018

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An increase in biochemical concentrations of non-transferrin bound iron (NTBI) within the patients with an increase in serum iron concentration was evaluated with the following objectives: (a) Iron overloading diseases/conditions with free radicle form of ‘iron containing’ reactive oxygen species (ROS) and its imbalance mediated mortality, and (b) Intervention with iron containing drugs in context to increased redox iron concentration and treatment induced mortality. Literature search was done within Pubmed and cochrane review articles. The Redox iron levels are increased during dys-erythropoiesis and among transfusion recipient population and are responsive to iron-chelation therapy. Near expiry ‘stored blood units’ show a significant rise in the ROS level. Iron mediated ROS damage may be estimated by the serum antioxidant level, and show reduction in toxicity with high antioxidant, low pro-oxidant levels. Iron drug therapy causes a significant increase in NTBI and labile iron levels. Hospitalized patients on iron therapy however show a lower mortality rate. Serum ferritin is a mortality indicator among the high-dose iron therapy and transfusion dependent population. The cumulative difference of pre-chelation to post chelation ROS iron level was 0.97 (0.62; 1.32; N=261) among the transfusion dependent subjects and 2.89 (1.81–3.98; N=130) in the post iron therapy ‘iron ROS’ group. In conclusion, iron mediated mortality may not be mediated by redox iron among multi-transfused and iron overloaded patients.

Keywords: Chelation antioxidants, Hepcidin, Non transferrin bound iron, Pro-oxidant effect, Serum ferritin, Transferrin saturation

Fig 1.

Figure 1.

Flow diagram: selected studies. Role of redox form of iron towards an increase in mortality among patients. A systemic review and meta-analysis.

Blood Research 2019; 54: 87-101https://doi.org/10.5045/br.2019.54.2.87

Fig 2.

Figure 2.

Studies included in qualitative synthesis and meta-analysis.

Blood Research 2019; 54: 87-101https://doi.org/10.5045/br.2019.54.2.87

Fig 3.

Figure 3.

(A) Forest Plot 1: Standard mean différence pre-chelation; post-chelation redox iron levels, (B) funnel plot [16202122343536].

Abbreviation: ROS, reactive oxygen species.

Blood Research 2019; 54: 87-101https://doi.org/10.5045/br.2019.54.2.87

Fig 4.

Figure 4.

(A) Forest plot 2 post-iron therapy redox iron levels, (B) funnel plot [22728293036].

Abbreviation: ROS, reactive oxygen species.

Blood Research 2019; 54: 87-101https://doi.org/10.5045/br.2019.54.2.87

Fig 5.

Figure 5.

(A) Forest plot 3 pooling of effects, ROS overloading conditions, odds ratio 0.89 (0.39, 2.02). (B) Funnel plot of studies [110373839404142].

Abbreviation: ROS, reactive oxygen species.

Blood Research 2019; 54: 87-101https://doi.org/10.5045/br.2019.54.2.87
Role of the stored blood and transferrin saturation in iron ROS increase.

Patient: Role of TS, NTBI, LPI in patient's mortality after receiving blood transfusion..

Setting: Review of studies; RCT; animal preclinical studiesa); Population studiesb)..

Interventions: The NTBI, LPI release in the RBC transfusions; hemolytic anemia; stored RBC units..

a)Review studies awarded moderate grading. b)Animal experimentation awarded moderate grading..

Abbreviations: LPI, labile plasma iron; NTBI, non transferrin bound iron; ROS, reactive oxygen species; TS, transferrin saturation..


Role of the increase antioxidants, and chelation therapy in iron ROS.

Abbreviations: DCI, directly chelatable iron; HCV, hepatitis C virus; HH, hereditary hemochromatosis; HR, hazard ratio; LPI, labile plasma iron; MDA, malondialdehyde..


Release of redox iron by iron drugs and comparison of towards patient prognosis.

Patient: TS, NTBI, LPI levels in iron pharmacological preparations; role of NTBI and LPI in mortality among patients..

Intervention: The NTBI, LPI release in iron formulations and level of serum ferritin and patient prognosis..


Summary of outcome.

Patient: Mortality after receiving blood transfusion, iron pharmacological preparations and role of NTBI and LPI..

Setting: review of studies; RCT; animal preclinical studies; a)population studies..

Interventions: role of TS, NTBI, and LPI in patient mortality in iron overload conditions, multi-transfused patients; iron pharmacological preparations..

Comparison: The NTBI, LPI increase during the RBC transfusions; hemolytic anemia; multi-transfusion anemia patients; iron formulations..

a)Animal preclinical studies were awarded moderate or below grading..

Abbreviations: DCI, directly chelatable iron; LPI, labile plasma iron; NTBI, non transferrin bound iron; ROS, reactive oxygen species; TS, transferrin saturation..


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