Protective role of zinc in the pathogenesis of respiratory diseases

Reference ranges for select elements and metals in healthy biomatrices

INTRODUCTION/OBJECTIVE

This review aimed to consolidate and compare reference values (RVs) for various elements and metals in biological samples from healthy populations worldwide.

METHODS

A Web of Science/PubMed/Scopus review was conducted. Original articles in the English language, from January 2012 to February 2022, with at least 120 participants and 3 evaluated elements, and biological samples of whole blood, serum, plasma, umbilical cord, and hair included in this review.

RESULTS

Ninety-nine studies were screened and assessed, and eventually, 29 eligible studies from 15 countries and a total recruitment of 26,676 healthy subjects, ages ranging from zero to 80 years were included in this review. The results of evaluating 36 trace/micro/meso/macro/ toxic metals and elements in biological fluids and hair were extracted from eligible studies. Several indicators include reference range (lower, upper), arithmetic and geometric mean, median, percentile (lower, upper), and confidence interval (CI) 95 % of evaluated elements were reported. Due to geographical conditions, different demographic factors, and different analytical methodologies, the results of the analysis were various in different countries.

CONCLUSIONS

This review points out the necessity for localized RVs and standardized methodologies for accurate clinical evaluations and bio-monitoring. The findings call for extensive studies across diverse populations to develop comprehensive RVs for elements and metals, ensuring effective health assessments and environmental exposure controls.

In Vitro and In Vivo Antibacterial and Antibiofilm Activity of Zinc Sulfate (ZnSO4) and Carvacrol (CV) Alone and in Combination with Antibiotics Against Pseudomonas aeruginosa

Background/Objectives: Biofilm-embedded bacteria, such as Pseudomonas aeruginosa (P. aeruginosa), are highly resistant to antibiotics, making their treatment challenging. Plant-based natural compounds (PBCs) and metal(loid)-based antimicrobials (MBAs) are promising alternatives. This study evaluated the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and synergistic effects of zinc sulfate (ZnSO4), carvacrol (CV), and antibiotics (ciprofloxacin [CIP], tobramycin [TOB], and azithromycin [AZM]) against P. aeruginosa PAO1. Methods: The MIC and MBC of ZnSO4, CV, and antibiotics were determined using a 96-well plate method. Cytotoxicity was assessed via MTT assay. Fractional inhibitory concentration (FIC), fractional bactericidal concentration (FBC), minimal biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC) indices were calculated for each combination of agents. Checkerboard assays identified interactions, and the effectiveness of combinations was further evaluated in a mouse chronic lung infection model with treatments delivered intratracheally, intraperitoneally, and orally. Results: TOB had the lowest MIC and MBC values, proving most effective against P. aeruginosa PAO1. Strong synergy was observed with CV + ZnSO4 (CV + Zn) combined with CIP, CV with CIP, and CV + Zn with TOB, as indicated by low FIC indices. CV + Zn with TOB and CV with TOB had low FBC indices, while CV + Zn with AZM showed antagonism. In vivo, intratracheal TOB + CV + Zn reduced lung inflammation and tissue involvement, yielding the best histopathological outcomes. The MIC of CIP and TOB was reduced 5-fold and 4-fold, respectively, when combined with CV + Zn. Conclusions: CV + Zn demonstrated strong synergistic effects with antibiotics and effectively managed P. aeruginosa lung infections in mice. These findings highlight its potential as an innovative therapy for biofilm-associated infections.

Energy and Key Micronutrient Intake in Amateur Swimmers: A Pilot Study

Swimming is a highly demanding sport that requires the integration of multiple physical, physiological, and psychological factors for optimal performance. Despite its popularity, most swimmers are amateur, and few studies have assessed energy and nutrient intake at this athlete level. Therefore, the aim of the present pilot study was to evaluate energy and nutrient intake and compare them with the recommended values. Methods: The participants were recruited from local teams. To determine body composition, weight, height, and skinfold measurements were taken. Food intake assessment was conducted through a 3-day food log. Results: The sample was composed of 15 individuals, where 7 were female. There were no significant differences in energy and macronutrient intake between male and female swimmers, nor between rest or workout days. Despite protein intake being within the recommendation, the estimated average intake for energy was significantly lower than the recommended values. Female swimmers also showed an inadequate intake of calcium, iron, and zinc. Conclusions: Swimmers showed an inadequate energy and carbohydrate intake for their activity level. Female athletes also reported a low intake of crucial micronutrients.

Zinc as a potential prophylactic adjuvant therapy for prolonged hospitalization: A systematic review and meta-analysis of an umbrella of randomized controlled trials

AIMS

The present study evaluated the effect of oral zinc supplementation on shortening hospital length of stay.

METHODS

A systematic review was conducted for randomized control trials in patients who were hospitalized regardless of age and cause of admission. Studies were collected from PubMed, Web of Science, SCOPUS, and the Cochrane Library until July 2023. Results were compared between the zinc group and those who received a placebo and/or the standard therapy.

RESULTS

Eight studies were qualified for our meta-analysis. Of the 1267 patients, 633 and 634 were in the zinc supplementation and control groups, respectively. The meta-analysis found that oral zinc supplementation group experienced a lower length of hospital stay than the control group (mean difference, -0.43 days; 95% confidence interval, -0.65 to -0.22; P < 0.0001; heterogeneity, I2 = 20%).

CONCLUSION

The administration of oral zinc supplements was associated with a slightly reduced duration of hospital stay.

The independent and joint relationships between dietary antioxidant intake with risk of chronic obstructive pulmonary disease and all-cause mortality: insights from NHANES

Background

Numerous studies have indicated that a diet rich in antioxidants can prevent Chronic Obstructive Pulmonary Disease (COPD). However, the relationship between combined dietary antioxidant intake and the risk of COPD remains unclear. The Comprehensive Dietary Antioxidant Index (CDAI) is a composite score of various dietary antioxidants, including vitamins A, C, E, zinc, selenium, and carotenoids. In this study, we examined the independent and joint associations of CDAI with the risk of COPD and all-cause mortality.

Methods

The analysis was conducted using data from the National Health and Nutrition Examination Survey (NHANES) spanning from 2013 to 2018. Multivariable weighted logistic and Cox regression models were employed to evaluate the correlations of CDAI (including vitamins A, C, E, zinc, selenium, and carotenoids) with the risk of COPD and all-cause mortality. Restricted cubic spline models were used to examine potential non-linear relationships. Sensitivity and stratified analyses were conducted to assess the robustness of the results.

Results

In this study, compared to the lowest quartile, the highest quartile of CDAI levels was significantly negatively associated with the risk of COPD (Odds Ratio [OR]: 0.47; 95% Confidence Interval [CI]: 0.22-0.97), exhibiting a non-linear relationship. Additionally, vitamins A, C, E, zinc, selenium, and carotenoids were also negatively associated with the risk of COPD. Furthermore, dietary antioxidant zinc in the second quartile (Hazard Ratio [HR]: 0.25; 95% CI: 0.10-0.62) was negatively associated with the risk of all-cause mortality compared to the lowest quartile. Subgroup analysis results remained stable, and sensitivity analysis did not support the association between selenium and the risk of COPD, with no substantial changes in the remaining associations.

Conclusion

Higher CDAI is inversely associated with the risk of COPD, and appropriate intake of the dietary antioxidant zinc may reduce all-cause mortality in COPD patients.

Impact of zinc on immunometabolism and its putative role on respiratory diseases

Zinc is the second most abundant trace mineral in the human body and plays a critical role in immune cell function and metabolism. Zinc deficiency impairs immune cell function and is associated with increased susceptibility to respiratory diseases, including pneumonia, influenza, and COVID-19. Zinc homeostasis, maintained by numerous zinc transporters and metal-binding proteins (ie, metallothionein), is essential for coordinating immune cell signaling, gene expression, and enzymatic activities in response to respiratory infections. This article highlights the emerging role of zinc in various aspects of immune function, particularly through its influence on cellular metabolism. Given the significant global burden of respiratory diseases, there is a need to identify effective nutritional interventions that could be readily leveraged to prevent and/or mitigate respiratory disease risk, particularly in older adults who are prone to zinc deficiency. However, the immunometabolic mechanisms underlying zinc's protective effects remain poorly characterized. Future research should focus on elucidating how micronutrients, such as zinc, can support changes in immune cell metabolism in response to infections. Such efforts will help determine how zinc metabolism and zinc intervention strategies may best be leveraged to prevent or mitigate respiratory disease.

Imbalanced and Unchecked: The Role of Metal Dyshomeostasis in Driving COPD Progression

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory condition characterized by persistent inflammation and oxidative stress, which ultimately leads to progressive restriction of airflow. Extensive research findings have cogently suggested that the dysregulation of essential transition metal ions, notably iron, copper, and zinc, stands as a critical nexus in the perpetuation of inflammatory processes and oxidative damage within the lungs of COPD patients. Unraveling the intricate interplay between metal homeostasis, oxidative stress, and inflammatory signaling is of paramount importance in unraveling the intricacies of COPD pathogenesis. This comprehensive review aims to examine the current literature on the sources, regulation, and mechanisms by which metal dyshomeostasis contributes to COPD progression. We specifically focus on iron, copper, and zinc, given their well-characterized roles in orchestrating cytokine production, immune cell function, antioxidant depletion, and matrix remodeling. Despite the limited number of clinical trials investigating metal modulation in COPD, the advent of emerging methodologies tailored to monitor metal fluxes and gauge responses to chelation and supplementation hold great promise in unlocking the potential of metal-based interventions. We conclude that targeted restoration of metal homeostasis represents a promising frontier for ameliorating pathological processes driving COPD progression.

The Role of Trace Elements in COPD: Pathogenetic Mechanisms and Therapeutic Potential of Zinc, Iron, Magnesium, Selenium, Manganese, Copper, and Calcium

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a progressive, inflammatory airway disorder characterized by a gradual decline in lung function and increased oxidative stress. Both oxidative stress and inflammation are central to its pathophysiology, with trace elements such as zinc, copper, iron, manganese, magnesium, selenium, and calcium playing key roles in various cellular processes.

OBJECTIVE

This article reviews the role of trace elements in COPD, focusing on their involvement in disease pathogenesis and their therapeutic potential. Specifically, we examine the effects of zinc, copper, iron, magnesium, manganese, selenium, and calcium in COPD.

METHODS

We performed a comprehensive narrative review of the literature across databases including PubMed, Web of Science, Cochrane Library, and Google Scholar, identifying studies that explore the therapeutic effects of trace elements in COPD. The studies included in the review consisted of cohort analyses, randomized controlled trials, and clinical investigations.

RESULTS

Zinc, copper, iron, magnesium, manganese, selenium, and calcium are critical to both the pathophysiology and management of COPD. These trace elements contribute to the regulation of inflammation, the modulation of oxidative stress, and the maintenance of lung function. Zinc and copper, for instance, reduce oxidative stress and modulate immune responses, while iron is essential for oxygen transport. Magnesium, manganese, selenium, and calcium are vital for muscle function, respiratory performance, reducing inflammation, and improving pulmonary function.

CONCLUSIONS

The minerals zinc, copper, iron, magnesium, manganese, selenium, and calcium may contribute to beneficial effects as part of the standard therapeutic management of COPD. Maintaining optimal levels of these trace elements may support the regulation of inflammatory processes, a reduction in oxidative stress, and an improvement in the pulmonary function. However, further clinical research is necessary to confirm their efficacy and establish safe dosage recommendations in COPD treatment.

Genetic information supports a causal relationship between trace elements, inflammatory proteins, and COPD: evidence from a Mendelian randomization analysis

Objective

Dietary factors and nutritional status may be among the risk factors for Chronic Obstructive Pulmonary Disease (COPD). There exists a certain correlation between trace elements and COPD. Through Mendelian Randomization (MR) analysis, we investigated the causal relationships between trace elements, inflammatory proteins, and COPD.

Methods

We employed MR, multivariable MR (MVMR), and two-step MR (TSMR) approaches to assess the causal links between 15 trace elements and COPD, with 91 inflammatory proteins serving as mediators to further elucidate the tripartite causal relationships.

Results

Trace elements such as Folate (OR = 1.293, 95%CI 1.027-1.628; p = 0.029), Vitamin D (OR = 1.331, 95%CI 1.071-1.654; p = 0.010), Vitamin B12 (OR = 1.424, 95%CI 1.108-1.828; p = 0.006), and Iron (OR = 0.741, 95%CI 0.580-0.946; p = 0.016) demonstrated causal relationships with COPD. No causal relationship was observed in reverse MR. After adjusting for BMI, Folate (OR = 1.633, 95%CI 1.098-2.429; p = 0.015), Iron (OR = 0.507, 95%CI 0.31-0.778; p = 0.001), and Vitamin D (OR = 1.511, 95%CI 1.029-2.217; p = 0.034) were identified as independent risk factors for COPD, whereas Vitamin B12 (OR = 1.118, 95%CI 0.751-1.666; p = 0.581) was not. Mediation analysis indicated that CDCP1 (5.76%) may play a mediating role between Iron and COPD.

Conclusion

Trace elements such as Folate, Vitamin D, Vitamin B12, and Iron have causal relationships with COPD. After BMI adjustment, Folate, Vitamin D, and Iron emerge as independent risk factors. Furthermore, the inflammatory protein CDCP1 may partially mediate the causal relationship between Iron and COPD, offering a scientific basis for dietary recommendations that could benefit COPD patients. The supplementation of trace elements may be advantageous for individuals suffering from COPD.

Turn-On Solid-State Fluorescent Determination of Zinc Ion by Quinoline-Based Covalent Organic Framework

A new quinoline-based COF (covalent organic framework), obtained by Povarov reaction, containing 2,6-diisopropylphenyl moieties as substituents over the heterocyclic ring is described for detecting Zn2+ in aqueous solution. The introduction of the mentioned bulky phenyl rings into the network favors an increase of the distance between the reticular sheets and their arrangement, obtaining a new material with an alternating AB type stacking. The new material exhibits good selectivity to detect Zn2+ by fluorescence emission in aqueous solutions up to a concentration of 1.2 × 10-4 m of the metal ion. In order to have a deeper insight into the interaction between the COF and the zinc cation, a thorough spectroscopical, microscopical, and theoretical study is also presented and discussed in this communication.

LLL 44 - Module 3: Micronutrients in Chronic disease

Micronutrients (MN), i.e. trace elements and vitamins, are essential organic molecules, which are required in the diet in relatively small amounts in any form of nutrition (oral, enteral, parenteral). The probability of MN depletion or deficiencies should be considered in all chronic illnesses, especially in those that can interfere with intake, digestion, or intestinal absorption. Low socio-economic status and food deprivation are recognized as the most prevalent reasons for MN deficiencies world-wide. Elderly multimorbid patients with multimodal therapy, as well as patients with long-lasting menu restrictions, are at high risk for both disease related malnutrition as well as multiple MN deficiencies, needing careful specific follow-up. The importance of monitoring MN blood levels along with CRP is essential for optimal care. Drug interactions are also highlighted. In patients with chronic conditions depending on medical nutrition therapy, the provision of adequate dietary reference intakes (DRI) of MN doses and monitoring of their adequacy belongs to standard of care.

Zinc status in cystic fibrosis patients; a systematic review and meta-analysis

Background

Cystic fibrosis (CF) is an autosomal recessive hereditary disease causes concentration of secretions and this affects the lungs and digestive system. These patients are exposed to zinc (zn) deficiency. In this review, we decided to investigate the status of zn in CF patients compared to control group. Also, the clinical trials that have so far performed zinc supplementation in these patients are examined.

Method

ISI Web of Science, Scopus, PubMed/Medline, and Cochrane database were searched, up to December 2023, for studies that reported the association between zn levels of CF patients compared to a healthy control group. A random-effect model was used to compute the pooled weighted mean difference (WMD) with 95 % confidence intervals (CI). Subgroup analysis was done for region, sample and method of measurement, zinc supplementation and age.

Result

Overall, meta-analysis of 9 studies (n = 383 participants) revealed that the zn levels were significantly lower in children and adolescents with CF compared with healthy subjects (WMD = -11.97 μg/dL, 95 % CI: -22.57 to -1.37; I2 = 92.83 %). Meta-analysis of 8 studies (n = 320 participants) revealed that the serum and plasma level of zn was significantly lower in CF patients compared with healthy subjects (WMD = -14.31 μg/dL, 95 % CI: -25.09 to -3.53; I2 = 88.14 %, P-heterogeneity <0.001) While the zn level in saliva and sputum was significantly higher in CF patients.

Conclusion

CF patients have decreased zn levels in circulatory reservoirs. zn may effective for the diminish the respiratory and gastrointestinal symptoms in CF patients, further well-designed clinical trial studies is required to prove these effects.

Structures, Mechanisms, and Physiological Functions of Zinc Transporters in Different Biological Kingdoms

Zinc transporters take up/release zinc ions (Zn2+) across biological membranes and maintain intracellular and intra-organellar Zn2+ homeostasis. Since this process requires a series of conformational changes in the transporters, detailed information about the structures of different reaction intermediates is required for a comprehensive understanding of their Zn2+ transport mechanisms. Recently, various Zn2+ transport systems have been identified in bacteria, yeasts, plants, and humans. Based on structural analyses of human ZnT7, human ZnT8, and bacterial YiiP, we propose updated models explaining their mechanisms of action to ensure efficient Zn2+ transport. We place particular focus on the mechanistic roles of the histidine-rich loop shared by several zinc transporters, which facilitates Zn2+ recruitment to the transmembrane Zn2+-binding site. This review provides an extensive overview of the structures, mechanisms, and physiological functions of zinc transporters in different biological kingdoms.

A dual-function fluorescence 'turn-on' probe that allows Zn (II) bioimaging and quantification of water in the organic solvent

Herein, a Eugenol-derived fluorescence 'turn-on' probe FLHE was synthesized by condensing 2-((3-(trifluoromethyl)phenyl)amino)benzohydrazide with 5-allyl-2-hydroxy-3-methoxybenzaldehyde. FLHE demonstrated very low fluorescence in the studied organic solvents of varying polarities. However, upon titration with Zn2+ in HEPES buffer (pH = 7.4, 50% ACN, v/v), FLHE showed 40-fold higher fluorescence signals indicating the formation of the FLHE-Zn2+ complex. The fluorescence turn-on phenomenon upon FLHE-Zn2+ complex formation results from a chelation-enhanced fluorescence (CHEF) effect. The FLHE-Zn2+ complexation demonstrated a stokes shift of 156 nm (λex = 350 nm, λem = 506 nm) and an about 33-fold increase in the quantum yield (FLHE, Φ = 0.007; FLHE-Zn2+ complex, Φ = 0.23). The binding constant (Ka) determined by the Benesi-Hildebrand plot for interaction between FLHE and Zn2+ was 5.33 × 103 M-1. FLHE demonstrated a LOD of 31.8 nM for detecting Zn2+ in the environmental samples without interference from other cations and anions. FLHE-based paper strip (FLHE-PS) assay was developed to quantify the Zn2+ ions in water and the water content of organic solvent. FLHE-PS allows the detection of Zn2+ in aqueous solutions with a LOD of 63.2 nM and quantifying water in acetonitrile with a LOD of 0.14%. These results indicate that the FLHE has high applicability for detecting Zn2+ in living cells and environmental samples and detecting the presence of water in the organic solvents.