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Moaaz M, Badreldin O, El Chazli Y, Fata A, Abougabal M. Race-neutral equations for assessment of lung function in children with thalassemia. Pediatr Pulmonol 2023; 58:2543-2550. [PMID: 37283241 DOI: 10.1002/ppul.26545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/21/2023] [Accepted: 05/29/2023] [Indexed: 06/08/2023]
Abstract
The aim of this study was to assess pulmonary dysfunction in children with transfusion-dependent thalassemia (TDT) using the Global Lung Function Initiative (GLI) 2022 race-neutral spirometric reference equations and to determine the main predicting factors. The spirometric results of 68 children with TDT were compared to the results of 68 healthy control subjects using both GLI-2012 reference equations for Caucasians and GLI-2022 global equations. Associations between the spirometric data and various anthropometric, clinical, and laboratory parameters were analyzed to detect predictors of pulmonary dysfunction in this group of patients. Children with TDT showed significantly lower values of FVC and FEV1 with a predominance of the restrictive pattern (23.53%). Thalassemic children with the restrictive pattern were significantly older, had a longer duration of regular blood transfusion, lower height, weight, and BMI z-scores, higher average serum ferritin, and higher frequency of having a serum ferritin level >2500 ng/mL. The strongest predictor for having a restrictive spirometric pattern was high serum ferritin. Our analysis shows that the transition from GLI-2012 spirometric reference equations for Caucasians to the GLI-2022 global equations has led to a reduction in the prevalence rate of restrictive pulmonary dysfunction in children with TDT, which should not affect the patient outcome in the long term. Asymptomatic children with TDT exhibited a restrictive spirometric pattern in a significant proportion. The most important predictor was high serum ferritin. We encourage the inclusion of pulmonary function testing in the routine monitoring of patients with TDT, especially in older patients and those with iron overload.
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Affiliation(s)
- Marwa Moaaz
- Department of Human Physiology, Clinical Respiratory Physiology Unit, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Omneya Badreldin
- Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Yasmine El Chazli
- Department of Pediatrics, Faculty of Medicine, Hematology/Oncology Unit, Alexandria University, Alexandria, Egypt
| | - Aya Fata
- Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mohamed Abougabal
- Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
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Pulmonary function in patients with transfusion-dependent thalassemia and its associations with iron overload. Sci Rep 2023; 13:3674. [PMID: 36871083 PMCID: PMC9985598 DOI: 10.1038/s41598-023-30784-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
In patients with transfusion-dependent thalassemia (TDT), pulmonary function impairment has been reported but data are conflicting. Moreover, it remains unclear whether pulmonary dysfunction is associated with iron overload. This study aimed to evaluate the pulmonary function in patients with TDT and to investigate the associations between pulmonary dysfunction and iron overload. It was a retrospective observational study. 101 patients with TDT were recruited for lung function tests. The most recent ferritin levels (pmol/L) and the magnetic resonance imaging (MRI) measurements of the myocardial and liver iron status, as measured by heart and liver T2* relaxation time (millisecond, ms) respectively, were retrieved from the computerized medical records. Only data within 12 months from the lung function measurement were included in the analysis. The serum ferritin, and the cardiac and liver T2* relaxation time were the surrogate indexes of body iron content. The threshold of abnormality in lung function was defined as under 80% of the predicted value. 101 subjects were recruited with a mean age of 25.1 years (standard deviation (SD) 7.9 years). Thirty-eight (38%) and five (5%) demonstrated restrictive and obstructive lung function deficits, respectively. A weak correlation of FVC %Predicted and TLC %Predicted with MRI myocardial T2* relaxation time (rho = 0.32, p = 0.03 and rho = 0.33, p = 0.03 respectively) was observed. By logistic regression, MRI cardiac T2* relaxation time was negatively associated with restrictive lung function deficit (B - 0.06; SE 0.03; Odds ratio 0.94; 95% confidence interval (CI) 0.89-0.99; p = 0.023) after adjusting for age, sex and body mass index. Restrictive pulmonary function deficit was commonly observed in patients with TDT, and the severity potentially correlates with myocardial iron content. Monitoring of lung function in this group of patients, particularly for those with iron overload, is important.
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Iron Homeostasis in the Lungs-A Balance between Health and Disease. Pharmaceuticals (Basel) 2019; 12:ph12010005. [PMID: 30609678 PMCID: PMC6469191 DOI: 10.3390/ph12010005] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/23/2018] [Accepted: 12/25/2018] [Indexed: 12/15/2022] Open
Abstract
A strong mechanistic link between the regulation of iron homeostasis and oxygen sensing is evident in the lung, where both systems must be properly controlled to maintain lung function. Imbalances in pulmonary iron homeostasis are frequently associated with respiratory diseases, such as chronic obstructive pulmonary disease and with lung cancer. However, the underlying mechanisms causing alterations in iron levels and the involvement of iron in the development of lung disorders are incompletely understood. Here, we review current knowledge about the regulation of pulmonary iron homeostasis, its functional importance, and the link between dysregulated iron levels and lung diseases. Gaining greater knowledge on how iron contributes to the pathogenesis of these diseases holds promise for future iron-related therapeutic strategies.
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Neves J, Leitz D, Kraut S, Brandenberger C, Agrawal R, Weissmann N, Mühlfeld C, Mall MA, Altamura S, Muckenthaler MU. Disruption of the Hepcidin/Ferroportin Regulatory System Causes Pulmonary Iron Overload and Restrictive Lung Disease. EBioMedicine 2017; 20:230-239. [PMID: 28499927 PMCID: PMC5478206 DOI: 10.1016/j.ebiom.2017.04.036] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 01/01/2023] Open
Abstract
Emerging evidence suggests that pulmonary iron accumulation is implicated in a spectrum of chronic lung diseases. However, the mechanism(s) involved in pulmonary iron deposition and its role in the in vivo pathogenesis of lung diseases remains unknown. Here we show that a point mutation in the murine ferroportin gene, which causes hereditary hemochromatosis type 4 (Slc40a1C326S), increases iron levels in alveolar macrophages, epithelial cells lining the conducting airways and lung parenchyma, and in vascular smooth muscle cells. Pulmonary iron overload is associated with oxidative stress, restrictive lung disease with decreased total lung capacity and reduced blood oxygen saturation in homozygous Slc40a1C326S/C326S mice compared to wild-type controls. These findings implicate iron in lung pathology, which is so far not considered a classical iron-related disorder. Ferroportin resistance to hepcidin binding leads to pulmonary iron overload. Lung iron accumulation is restricted to specific cell types. Iron overload causes restrictive lung disease and decreased blood oxygen saturation.
Pulmonary iron accumulation is associated with a wide spectrum of lung diseases, such as chronic obstructive pulmonary disease and cystic fibrosis. Impaired lung function was further reported in patients with thalassemia major, a disease hallmarked by transfusional iron overload. So far, the mechanism(s) leading to pulmonary iron deposition and its role in disease onset and progression are still unknown. Our study shows that in a murine disease model, in which the control of systemic iron homeostasis is disrupted, iron accumulates in the lung and correlates with oxidative stress, restrictive lung disease and decreased blood oxygen saturation. These findings implicate iron overload in lung pathology, which is not considered a classical iron-related disorder.
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Affiliation(s)
- Joana Neves
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany; Molecular Medicine Partnership Unit, D-69120 Heidelberg, Germany; Graduate Program in Areas of Basic and Applied Biology, Abel Salazar Biomedical Sciences Institute, University of Porto, 4050-343 Porto, Portugal; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, D-69120 Heidelberg, Germany
| | - Dominik Leitz
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, D-69120 Heidelberg, Germany; Department of Translational Pulmonology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Simone Kraut
- Justus-Liebig University of Giessen (JLUG), Excellence Cluster Cardiopulmonary System (ECCPS), Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Germany
| | - Christina Brandenberger
- Institute of Functional and Applied Anatomy, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover Medical School, D-30625 Hannover, Germany
| | - Raman Agrawal
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, D-69120 Heidelberg, Germany; Department of Translational Pulmonology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Norbert Weissmann
- Justus-Liebig University of Giessen (JLUG), Excellence Cluster Cardiopulmonary System (ECCPS), Universities of Giessen and Marburg Lung Center (UGMLC), German Center for Lung Research (DZL), Germany
| | - Christian Mühlfeld
- Institute of Functional and Applied Anatomy, Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover Medical School, D-30625 Hannover, Germany
| | - Marcus A Mall
- Molecular Medicine Partnership Unit, D-69120 Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, D-69120 Heidelberg, Germany; Department of Translational Pulmonology, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Sandro Altamura
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany; Molecular Medicine Partnership Unit, D-69120 Heidelberg, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany; Molecular Medicine Partnership Unit, D-69120 Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, D-69120 Heidelberg, Germany.
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