Asthma as a disruption in iron homeostasis

Prevalence of anemia and its associated factors among adult asthmatic patients in Northwest Ethiopia

BACKGROUND

Asthma is a heterogeneous disease characterized by chronic airway inflammation. The pathophysiologic processes of asthma can disrupt iron homeostasis, resulting in anemia. However, the association between asthma and anemia among adult asthma patients remains limited. Therefore, the main aim of this study was to determine the prevalence and factors associated with anemia among adult asthmatic patients from May to August 2021.

METHODS

An institution-based, cross-sectional study was conducted among 291 asthmatic patients in Northwest Ethiopia. A pre-tested structured questionnaire and checklist were used to collect sociodemographic and clinical data. A blood specimen was collected from asthmatic patients for a complete blood count analysis and morphology assessment. The data were entered into the Epi data software and exported to the statistical package for social science version 20 software for analysis. Non-parametric Mann-Whitney U test was used to compare red blood cell parameters among groups with acute and chronic exacerbations. Binary logistic regression models were used to determine the factors associated with anemia. A p-value less than 0.05 was considered statistically significant.

RESULT

The overall prevalence of anemia in this study was 11% (95% CI: 7.2-14.8%). Acutely exacerbated asthmatic patients had significantly lower median values of red blood cell parameters such as red blood cell count, hemoglobin, and mean cell hemoglobin when compared to chronic exacerbations. In addition, using systemic corticosteroids (AOR = 4.07, 95% CI: 1.126-14.71, p = 0.032) and being hospitalized in the emergency department (AOR = 3.74, 95% CI: 1.26-11.07, p = 0.017) were found to be significantly associated with anemia.

CONCLUSION

This study demonstrated that anemia was predominant in adult asthma patients. Red blood cell number, hemoglobin level, and mean corpuscular hemoglobin were significantly lower in acute asthma exacerbations. Therefore, appropriate intervention strategies should be undertaken to reduce the prevalence of anemia among adult asthma patients to reduce further complications and provide better monitoring of asthma patients.

Plasma levels of oxysterols 7-ketocholesterol and cholestane-3β, 5α, 6β-triol in patients with allergic asthma

The prevalence of allergic asthma is increasing on a global scale, reflecting changes in air pollution, climatic changes, and other environmental stimulants. In allergic conditions, oxidative stress occurs as a result of immune system activation. Oxidation of cholesterol leads to the formation of oxysterols. The main purpose of the study was to compare plasma levels of two oxysterols, namely 7-ketocholesterol (7-KC) and cholestane-3β, 5α, 6β-triol (C-triol), and a lipid peroxidation product, malondialdehyde (MDA) in allergic asthma patients with those of healthy controls, in order to provide information about the involvement of lipid peroxidation in allergic asthma.

Oxysterols were quantified by LC-MS/MS in plasma samples of 120 asthma patients (90 females + 30 males) and 120 healthy controls (matched by age and sex). Plasma MDA level was analyzed by a spectrophotometric method.

Plasma 7-KC (39.45 ± 20.37 ng/mL) and C-triol (25.61 ± 10.13 ng/mL) levels in patients were significantly higher than in healthy subjects (17.84 ± 4.26 ng/mL and 10.00 ± 3.90 ng/mL, respectively) (P < 0.001). Plasma MDA levels were also higher in asthmatic patients (4.98 ± 1.77 nmol/mL) than in healthy controls (1.14 ± 0.31 nmol/mL) (P < 0.001). All data support that lipid peroxidation products are involved in allergic asthma.

Oxysterols were quantified for the first time in allergic asthma. Since the high plasma 7-KC and C-triol levels of allergic asthma patients correlate with high IgE levels, detection of these oxysterols by LC-MS/MS may be helpful in the clinical monitoring of allergic asthma. Current data may also lead to new approaches for the prevention, diagnosis, and treatment of the disease.

Supplemental data for this article is available online at at.

Iron status and its relation to lung function in pediatric asthmatics: a cross-sectional study

Background

Asthma and iron deficiency are common pediatric conditions. In addition, iron deficiency may affect spirometry results in asthmatic children. So, we aimed to assess the effect of ion status on lung function in childhood asthma.

Results

In this cross-sectional study, fifty asthmatic pediatric patients aged from 6 to 16 years presented to our institute during the period from (June 2018 to December 2018) were enrolled. Asthmatic patients were classified according to their complete blood count and iron profile into 2 groups: group 1, asthmatic children without iron deficiency anemia (IDA); and group 2, asthmatic children with IDA. All patients underwent full history taking, clinical examination, laboratory investigations, asthma control test, and pulmonary function tests (PFTs). The study showed that PFTs’ parameters (forced expiratory volume in one second (FEV1) % of predicted, FEV1/forced vital capacity, and maximal mid expiratory flow (MMEF) 25–75% of predicted) were significantly lower among asthmatics with IDA (80.62 ± 18.13, 78.36 ± 11.22, 62.35 ± 26.67) than among asthmatics without IDA (93.45 ± 15.51, 87.68 ± 10.81, 82.10 ± 24.74), respectively (p =0.012, 0.006, 0.012). Also, poorly controlled asthma was significantly higher among asthmatics with IDA (p =0.001). In addition, there was a statistically significant positive correlation between forced spirometry parameters, hemoglobin, and ferritin level (p=0.012, 0.042). Moreover, there was a significant positive correlation between hemoglobin level and MMEF 25–75% of predicted (p=0.012).

Conclusions

Lower iron status negatively affects the lung function in asthmatic children with a more obstructive pattern among asthmatics with IDA.

A PET-based fluorescent probe for monitoring labile Fe(II) pools in macrophage activations and ferroptosis

A fluorescent probe (COU-LIP-1) for monitoring labile Fe(II) pools (LIP) with high selectivity and sensitivity was developed utilizing coumarin 343 as the fluorophore and 3-nitrophenylazanyl ester as both the reactive group and the fluorescence quenching group. Fe(II)-induced reductive cleavage of the N-O bond results in a turn-on response via a photo-induced photon transfer (PET) mechanism. The probe was applied for monitoring labile iron(II) changes in M1 and M2a macrophage activations and also erastin-induced ferroptosis, providing a powerful tool for selectively sensing LIP under both physiological and stressed conditions.

Cigarette Smoke Particle-Induced Lung Injury and Iron Homeostasis

It is proposed that the mechanistic basis for non-neoplastic lung injury with cigarette smoking is a disruption of iron homeostasis in cells after exposure to cigarette smoke particle (CSP). Following the complexation and sequestration of intracellular iron by CSP, the host response (eg, inflammation, mucus production, and fibrosis) attempts to reverse a functional metal deficiency. Clinical manifestations of this response can present as respiratory bronchiolitis, desquamative interstitial pneumonitis, pulmonary Langerhans’ cell histiocytosis, asthma, pulmonary hypertension, chronic bronchitis, and pulmonary fibrosis. If the response is unsuccessful, the functional deficiency of iron progresses to irreversible cell death evident in emphysema and bronchiectasis. The subsequent clinical and pathological presentation is a continuum of lung injuries, which overlap and coexist with one another. Designating these non-neoplastic lung injuries after smoking as distinct disease processes fails to recognize shared relationships to each other and ultimately to CSP, as well as the common mechanistic pathway (ie, disruption of iron homeostasis).

Mineral Micronutrients in Asthma

Asthma represents one of the most common medical issues in the modern world. It is a chronic inflammatory disease characterized by persistent inflammation of the airways and disturbances in redox status, leading to hyperresponsiveness of bronchi and airway obstruction. Apart from classical risk factors such as air pollution, family history, allergies, or obesity, disturbances of the levels of micronutrients lead to impairments in the defense mechanisms of the affected organism against oxidative stress and proinflammatory stimuli. In the present review, the impact of micronutrients on the prevalence, severity, and possible risk factors of asthma is discussed. Although the influence of classical micronutrients such as selenium, copper, or zinc are well known, the effects of those such as iodine or manganese are only rarely mentioned. As a consequence, the aim of this paper is to demonstrate how disturbances in the levels of micronutrients and their supplementation might affect the course of asthma.

Abnormal iron status is independently associated with reduced oscillometric lung function in schoolchildren

BACKGROUND

Associations between anemia and allergic diseases have been reported, but the relationship of iron deficiency with airway dysfunction in children remains unclear. We aimed to investigate the relationship between abnormal iron parameters and lung function in schoolchildren.

METHODS

Four hundred and forty-five children (10-12 years-old) from 11 elementary schools in were enrolled. The relationships of different iron parameters (hemoglobin, serum iron, transferrin saturation, and serum ferritin) with lung function evaluated by impulse oscillometry (airways resistance at 5 Hz [Rrs5], 10 Hz [Rrs10], and the difference of Rrs5 and Rrs20 Hz [Rrs5-20]), and with exhaled nitric oxide (FeNO) were evaluated after adjustment for confounders including height, sex, and body mass index z-score, and for additional covariates that could affect airway function.

RESULTS

Total airway dysfunction represented by Rrs5 was reduced in participants with low serum iron level (aβ: -0.13, 95% CI: -0.23 to -0.03, p = 0.040) after adjustment for key confounders, but did not correlate with other iron profiles. Reduced oscillometric lung function recorded as Rrs5-20 was related with low serum iron and high serum ferritin, but the results were inconsistent after multiple comparisons. Associations were not observed with serum hemoglobin.

CONCLUSIONS

Decreased serum iron level was related with airway dysfunction represented as oscillomteric Rrs5. Our results suggest a relationship of reduced lung function with abnormal iron status in children.

The association between serum iron status and risk of asthma: a 2-sample Mendelian randomization study in descendants of Europeans

BACKGROUND

Observational studies present conflicting results about a possible association of iron status with asthma risk, pointing to potential modifiable targets for prevention.

OBJECTIVE

The aim of this study was to use Mendelian randomization (MR) to estimate associations between iron status and asthma risk.

METHODS

We used the Genetics of Iron Status consortium to identify genetic variants that could be used as instrumental variables for the effect of systemic iron status. The following sets of instruments were used: a conservative set (instruments restricted to variants with concordant relations to 4 iron status biomarkers) and a liberal set (instruments selected using variants associated with at least 1 of 4 iron status biomarkers). Associations of these genetic variants with asthma risk were estimated in data from the Trans-National Asthma Genetics Consortium (TAGC) and the GABRIEL consortium (A Multidisciplinary Study to Identify the Genetic and Environmental Causes of Asthma in the European Community). Data on the association of genetic variants with iron status and with asthma were combined to assess the influence of iron status on asthma risk.

RESULTS

In the conservative approach, the MR OR of asthma was 1.00 (95% CI: 0.91, 1.10) per SD increase in iron, 0.96 (95% CI: 0.78, 1.18) in log-transformed ferritin, 0.99 (95% CI: 0.93, 1.06) in transferrin saturation, and 1.03 (95% CI: 0.93, 1.14) in transferrin in the TAGC dataset (none of the values were statistically significant). An age at onset-stratified analysis in the GABRIEL dataset suggested no effect of iron status in childhood onset, later onset, or unknown age at onset asthma. Findings from the liberal approach were similar, and the results persisted in sensitivity analyses (all P > 0.05).

CONCLUSIONS

This MR study does not provide evidence of an effect of iron status on asthma, suggesting that efforts to change iron concentrations will probably not result in decreased risk of asthma.

Antibiotic overuse and allergy-related diseases: an epidemiological cross-sectional study in the grasslands of Northern China

Background

Several studies have shown that the use of antibiotics early in life significantly increases the risk of asthma in children. It is unclear whether antibiotics are more commonly used in patients with allergy-related diseases.

Methods

A multistage, clustered and random sampling with a field-interviewer-administrated survey study was performed to investigate if there was multiple use of antibiotics (MUA) in patients with allergic rhinitis (AR), conjunctivitis, chronic urticaria (CU), and asthma in the grasslands of northern China. MUA was defined as antibiotic usage for at least 3 days and for more than 3 times a year in the past 2 years.

Results

A total of 5,787 subjects completed the study, with 1,079 subjects (18.6%) identified as MUA. MUA was more common in patients with AR (23.7% vs 16.2%, P<0.001), conjunctivitis (22.5% vs 17.1%, P<0.001), asthma (31.8% vs 17.7%, P<0.001), and CU (25.9% vs 18.3%, P<0.01) than in subjects without allergic diseases. There is an increasing percentage of MUA in patients with a single, two, and three or more diseases both in children (20.1%, 25.0%, and 31.4%, respectively, P=0.014) and in adults (19.1%, 23.4%, and 32.9%, respectively, P<0.001). MUA is significantly associated with AR (OR=1.7, 95% CI: 1.3-2.1, P<0.001), conjunctivitis (OR=1.6, 95% CI: 1.2-2.1, P=0.001), asthma (OR=2.3, 95% CI:1.6-3.3, P<0.001) and CU (OR=2.1, 95% CI: 1.2-3.6, P=0.006) in children aged 2-17 years; and in adults (≥18 years old) for AR (OR=1.7, 95% CI: 1.4-2.1, P<0.001), conjunctivitis (OR=1.3, 95% CI:1.1-1.6, P=0.002), and asthma (OR=2.0, 95% CI: 1.5-2.7, P<0.001).

Conclusion

Antibiotic overuse might be associated with increased risk of allergy-related disease. It is important that implementation of the evidence-based international guidelines for the management of allergy-related diseases needs to be improved, in order to avoid unnecessary use of antibiotics.

Iron Homeostasis in the Lungs-A Balance between Health and Disease

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.