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.

Zinc ameliorates acrylamide-induced oxidative stress and apoptosis in testicular cells via Nrf2/HO-1/NfkB and Bax/Bcl2 signaling pathway

BACKGROUND

Acrylamide is a toxic substance formed in some foods that require high-temperature cooking processes and has been implicated as a gonadotoxic agent. Zinc, on the other hand, is a known antioxidant with fertility-enhancing properties. Hence, this study was designed to explore the possible ameliorative effect of zinc in acrylamide-induced gonadotoxicity.

METHODS

Twenty-four male Wistar rats were randomized into control, acrylamide (10 mg/kg of acrylamide), acrylamide + 1 mg/kg of zinc, and acrylamide + 3 mg/kg of zinc. The administration was via the oral route and lasted for 56 days.

RESULTS

Zinc treatment ameliorated acrylamide-impaired sperm quality, normal testicular histoarchitecture, and hormonal balance, which was accompanied by increased testicular malondialdehyde and interleukin-1β and decreased testicular superoxide dismutase (SOD) and catalase (CAT). Furthermore, zinc prevented acrylamide-induced downregulation of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and B-cell lymphoma 2 (BCl2) expression and upregulation of testicular nuclear factor kappa B (NF-κB) and bcl-2-like protein 4 (bax) expression.

CONCLUSION

In conclusion, zinc may protect against acrylamide-induced testicular toxicity, mediated by its antioxidant, anti-inflammatory, and antiapoptotic effects.

Intracellular Zn2+ promotes extracellular matrix remodeling in dexamethasone-treated trabecular meshwork

Given the widespread application of glucocorticoids in ophthalmology, the associated elevation of intraocular pressure (IOP) has long been a vexing concern for clinicians, yet the underlying mechanisms remain inconclusive. Much of the discussion focuses on the extracellular matrix (ECM) of trabecular meshwork (TM). It is widely agreed that glucocorticoids impact the expression of matrix metalloproteinases (MMPs), leading to ECM deposition. Since Zn2+ is vital for MMPs, we explored its role in ECM alterations induced by dexamethasone (DEX). Our study revealed that in human TM cells treated with DEX, the level of intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. This correlated with changes in several Zrt-, Irt-related proteins (ZIPs) and metallothionein. ZIP8 knockdown impaired extracellular Zn2+ uptake, but Zn2+ chelation did not affect ZIP8 expression. Resembling DEX's effects, chelation of Zn2+ decreased MMP2 expression, increased the deposition of ECM proteins, and induced structural disarray of ECM. Conversely, supplementation of exogenous Zn2+ in DEX-treated cells ameliorated these outcomes. Notably, dietary zinc supplementation in mice significantly reduced DEX-induced IOP elevation and collagen content in TM, thereby rescuing the visual function of the mice. These findings underscore zinc's pivotal role in ECM regulation, providing a novel perspective on the pathogenesis of glaucoma.NEW & NOTEWORTHY Our study explores zinc's pivotal role in mitigating extracellular matrix dysregulation in the trabecular meshwork and glucocorticoid-induced ocular hypertension. We found that in human trabecular meshwork cells treated with dexamethasone, intracellular Zn2+ significantly decreased, accompanied by impaired extracellular Zn2+ uptake. Zinc supplementation rescues visual function by modulating extracellular matrix proteins and lowering intraocular pressure, offering a direction for further exploration in glaucoma management.

A flow equilibrium of zinc in cells of Cupriavidus metallidurans

The hypothesis was tested that a kinetical flow equilibrium of uptake and efflux reactions is responsible for balancing the cellular zinc content. The experiments were done with the metal-resistant bacterium Cupriavidus metallidurans. In pulse-chase experiments, the cells were loaded with radioactive 65Zn and chased with the 100-fold concentration of non-radioactive zinc chloride. In parallel, the cells were loaded with isotope-enriched stable 67Zn and chased with non-enriched zinc to differentiate between zinc pools in the cell. The experiments demonstrated the existence of a kinetical flow equilibrium, resulting in a constant turnover of cell-bound zinc ions. The absence of the metal-binding cytoplasmic components, polyphosphate and glutathione, metal uptake, and metal efflux systems influenced the flow equilibrium. The experiments also revealed that not all zinc uptake and efflux systems are known in C. metallidurans. Cultivation of the cells under zinc-replete, zinc-, and zinc-magnesium-starvation conditions influenced zinc import and export rates. Here, magnesium starvation had a stronger influence compared to zinc starvation. Other metal cations, especially cobalt, affected the cellular zinc pools and zinc export during the chase reaction. In summary, the experiments with 65Zn and 67Zn demonstrated a constant turnover of cell-bound zinc. This indicated that simultaneously occurring import and export reactions in combination with cytoplasmic metal-binding components resulted in a kinetical flow equilibrium that was responsible for the adjustment of the cellular zinc content.

IMPORTANCE

Understanding the biochemical action of a single enzyme or transport protein is the pre-requisite to obtain insight into its cellular function but this is only one half of the coin. The other side concerns the question of how central metabolic functions of a cell emerge from the interplay of different proteins and other macromolecules. This paper demonstrates that a flow equilibrium of zinc uptake and efflux reactions is at the core of cellular zinc homeostasis and identifies the most important contributors to this flow equilibrium: the uptake and efflux systems and metal-binding components of the cytoplasm.

Zinc utilization by microglia in Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia defined by two key pathological characteristics in the brain, amyloid-β (Aβ) plaques and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau. Microglia, the primary innate immune cells of the central nervous system (CNS), provide neuroprotection through Aβ and tau clearance, but may also be neurotoxic by promoting neuroinflammation to exacerbate Aβ and tau pathogenesis in AD. Recent studies have demonstrated the importance of microglial utilization of nutrients and trace metals in controlling their activation and effector functions. Trace metals, such as zinc, have essential roles in brain health and immunity, and zinc dyshomeostasis has been implicated in AD pathogenesis. As a result of these advances, the mechanisms by which zinc homeostasis influences microglial-mediated neuroinflammation in AD is a topic of continuing interest since new strategies to treat AD are needed. Here, we review the roles of zinc in AD, including zinc activation of microglia, the associated neuroinflammatory response, and the application of these findings in new therapeutic strategies.

Potentials and limitations of a food group-based algorithm to assess dietary nutrient intake of women in rural areas in Tanzania

The aim of this study was to evaluate the accuracy of nutrient intake assessment with the food group-based algorithm "Calculator of Inadequate Micronutrient Intake" (CIMI) in comparison to the established nutrition software NutriSurvey. Using Food Frequency Questionnaires and 24-h dietary recalls of 1010 women from two rural districts in Tanzania, 23 relevant typical Tanzanian food groups were identified and subsequently the dietary protocols assessed via CIMI algorithm were compared by bivariate correlations and Bland-Altman analysis with the results of the NutriSurvey software (reference) and were set in relation to blood biomarkers of 666 participants. CIMI and NutriSurvey calculations regarding macro- and micronutrient intakes were similar. The Bland-Altman analyses and correlation coefficients of energy (0.931), protein (0.898), iron (0.775) and zinc (0.838) confirm the agreement of both calculations. The food group based CIMI algorithm is a practical tool to identify the inadequacy of macro- and micronutrient intake at population level.

Critical Amino Acid Residues Regulating TRPA1 Zn2+ Response: A Comparative Study Across Species

Cellular zinc ions (Zn2+) are crucial for signal transduction in various cell types. The transient receptor potential (TRP) ankyrin 1 (TRPA1) channel, known for its sensitivity to intracellular Zn2+ ([Zn2+]i), has been a subject of limited understanding regarding its molecular mechanism. Here, we employed metal ion-affinity prediction, three-dimensional structural modeling, and mutagenesis, utilizing data from the Protein Data Bank and AlphaFold Database, to elucidate the [Zn2+]i binding domain (IZD) structure composed by specific amino acid residues (AAs) in human (hTRPA1) and chicken TRPA1 (gTRPA1). External Zn2+ induced activation in hTRPA1, while not in gTRPA1. Moreover, external Zn2+ elevated [Zn2+]i specifically in hTRPA1. Notably, both hTRPA1 and gTRPA1 exhibited inherent sensitivity to [Zn2+]i, as evidenced by their activation upon internal Zn2+ application. The critical AAs within IZDs, specifically histidine at 983/984, lysine at 711/717, tyrosine at 714/720, and glutamate at 987/988 in IZD1, and H983/H984, tryptophan at 710/716, E854/E855, and glutamine at 979/980 in IZD2, were identified in hTRPA1/gTRPA1. Furthermore, mutations, such as the substitution of arginine at 919 (R919) to H919, abrogated the response to external Zn2+ in hTRPA1. Among single-nucleotide polymorphisms (SNP) at Y714 and a triple SNP at R919 in hTRPA1, we revealed that the Zn2+ responses were attenuated in mutants carrying the Y714 and R919 substitution to asparagine and proline, respectively. Overall, this study unveils the intrinsic sensitivity of hTRPA1 and gTRPA1 to [Zn2+]i mediated through IZDs. Furthermore, our findings suggest that specific SNP mutations can alter the responsiveness of hTRPA1 to extracellular and intracellular Zn2+.

Zinc and manganese homeostasis closely interact in mammalian cells

Understanding the homeostatic interactions among essential trace metals is important for explaining their roles in cellular systems. Recent studies in vertebrates suggest that cellular Mn metabolism is related to Zn metabolism in multifarious cellular processes. However, the underlying mechanism remains unclear. In this study, we examined the changes in the expression of proteins involved in cellular Zn and/or Mn homeostatic control and measured the Mn as well as Zn contents and Zn enzyme activities to elucidate the effects of Mn and Zn homeostasis on each other. Mn treatment decreased the expression of the Zn homeostatic proteins metallothionein (MT) and ZNT1 and reduced Zn enzyme activities, which were attributed to the decreased Zn content. Moreover, loss of Mn efflux transport protein decreased MT and ZNT1 expression and Zn enzyme activity without changing extracellular Mn content. This reduction was not observed when supplementing with the same Cu concentrations and in cells lacking Cu efflux proteins. Furthermore, cellular Zn homeostasis was oppositely regulated in cells expressing Zn and Mn importer ZIP8, depending on whether Zn or Mn concentration was elevated in the extracellular milieu. Our results provide novel insights into the intricate interactions between Mn and Zn homeostasis in mammalian cells and facilitate our understanding of the physiopathology of Mn, which may lead to the development of treatment strategies for Mn-related diseases in the future.

Trace mineral source and chromium propionate supplementation affect performance and carcass characteristics in feedlot steers

Angus-crossbred steers (n = 400; 369.7 ± 7.6 kg) were used to determine the influence of trace mineral (TM) source and chromium propionate (Cr Prop) supplementation on performance, carcass characteristics, and ruminal and plasma variables in finishing steers. Steers were blocked by body weight (BW) and randomly assigned within block to treatments in a 2 x 2 factorial arrangement, with factors being: 1) TM source (STM or HTM) and 2) Cr supplementation (0 or 0.25 mg Cr/kg DM, -Cr or +Cr, respectively). Treatments consisted of the addition of: 1) sulfate TM (STM; 90, 40, and 18 mg/kg DM of Zn, Mn, and Cu, respectively), 2) STM and 0.25 mg Cr/kg DM from Cr Prop, 3) hydroxychloride TM (HTM; 90, 40, and 18 mg/kg DM of Zn, Mn, and Cu, respectively), and 4) HTM and 0.25 mg Cr/kg DM from Cr Prop. Each treatment consisted of 10 replicate pens with 10 steers per pen. Body weights were obtained on consecutive days at the initiation and termination of the 154-d study. Steers were fed a steam-flaked corn-based finishing diet. Ractopamine hydrochloride was fed for the last 31 d of the study. Ruminal fluid and blood samples were obtained from one steer per pen on d 28 and 84 for ruminal volatile fatty acids (VFA) and plasma TM and glucose analysis. Steers were slaughtered at the end of the study and individual carcass data were collected. No Cr x TM source interactions were detected. Steers supplemented with HTM had greater (P ˂ 0.04) hot carcass weight (HCW), dressing percentage (DP), longissimus muscle (LM) area, and USDA yield grade (YG), and tended (P ˂ 0.12) to have greater average daily gain (ADG) than those receiving STM. Average daily gain, gain:feed, dressing percentage, and longissimus muscle area were greater (P ˂ 0.04) for +Cr steers compared to - Cr steers. Hot carcass weight tended (P ˂ 0.06) to be greater for +Cr steers. Ruminal acetate concentrations at 28 d were lesser (P ˂ 0.01) for HTM vs. STM steers, and greater (P ˂ 0.04) for +Cr steers compared to - Cr steers. Plasma concentrations of Zn, Cu, and Mn were not affected by TM source or Cr supplementation. Steers supplemented with Cr had greater (P ˂ 0.05) plasma glucose concentrations than - Cr steers at 28 but not at 84 d. Results of this study indicate replacing STM with HTM improved carcass characteristics in finishing steers, and Cr Prop supplementation improved steer performance and carcass characteristics.

A systematic review of the association between zinc and anxiety

CONTEXT

The incidence of anxiety, which stems from both intrinsic and extrinsic factors, has been increasing worldwide. Various methods by which it can be treated or prevented have been reported thus far. One of the most popular and effective treatments is supplementation therapy. Zinc, which is an essential nutrient found in various plants, animal foods, and supplements, has been shown to be a potential nutrient in anxiety reduction by acting on γ-aminobutyric acid (GABA), glutamatergic, serotonergic, neurogenesis, and immune systems. It can also influence important receptors, such as GPR39. Thus, zinc has received considerable attention with respect to its potential role as a therapeutic or detrimental factor for anxiety; yet, the available evidence needs to be analyzed systematically to reach a convergent conclusion.

OBJECTIVE

The objective was to systematically review any potential connection between adult human anxiety and zinc intake.

DATA SOURCES AND EXTRACTION

Nine original human studies, of which 2 assessed the relationship between zinc consumption and anxiety (based on a questionnaire) and 7 assessed the relationship between serum zinc levels and anxiety, were included based on specific selection criteria. Studies that had been written in English and published in peer-reviewed publications with no restrictions on the date of publication were searched in the Google Scholar and PubMed databases. This project was also reported according to the PRISMA guidelines.

DATA ANALYSIS

As per the studies analyzed in this review, there was a noticeable relationship between serum zinc levels and anxiety, which means that patients with anxiety have lower levels of zinc in their serum, as compared with healthy individuals. Furthermore, zinc consumption was inversely associated with anxiety.

CONCLUSION

The results provide plausible evidence for the positive role of zinc in the treatment of patients afflicted with anxiety, albeit with some limitations.

1710 to zinc toxicity

Zinc (Zn) is an essential trace element but can lead to water contamination and ecological deterioration when present in excessive amounts. Therefore, investigating the photosynthetic response of microalgae to Zn stress is of great significance. In this study, we assessed the photosynthetic responses of neutrophilic Chlamydomonas reinhardtii and acidophilic Chlamydomonas sp. 1710 to Zn exposure for 96 h. The specific growth rate (μ), chlorophyll-a (Chl-a) content, and chlorophyll fluorescence parameters were determined. The results demonstrated that Chlamydomonas sp. 1710 was much more tolerant to Zn than C. reinhardtii, with the half-maximal inhibitory concentration (IC50) values of 225.4 mg/L and 23.4  mg/L, respectively. The μ and Chl-a content of C. reinhardtii decreased in the presence of 15  mg/L Zn, whereas those of Chlamydomonas sp. 1710 were unaffected by as high as 100  mg/L Zn. Chlorophyll fluorescence parameters indicated that the regulation of energy dissipation, including non-photochemical quenching, played a crucial role in Zn stress resistance for both Chlamydomonas strains. However, in the case of C. reinhardtii, non-photochemical quenching was inhibited by 5  mg/L Zn in the first 48 h, whereas for Chlamydomonas sp. 1710, it remained unaffected under 100  mg/L Zn. Chlamydomonas sp. 1710 also exhibited a 20 times stronger capacity for regulating the electron transfer rate than C. reinhardtii under Zn stress. The light energy utilization efficiency (α) of Chlamydomonas sp. 1710 had the most highly non-linear correlation with μ, indicating the energy utilization and regulation process of Chlamydomonas sp. 1710 was well protected under Zn stress. Collectively, our findings demonstrate that the photosystem of Chlamydomonas sp. 1710 is much more resilient and tolerant than that of C. reinhardtii under Zn stress.

Zinc(II) Iminopyridine Complexes as Antibacterial Agents: A Structure-to-Activity Study

Antibiotic resistance is currently a global health emergency. Metallodrugs, especially metal coordination complexes, comprise a broad variety of candidates to combat antibacterial infections. In this work, we designed a new family of Schiff base zinc(II) complexes with iminopyridine as an organic ligand and different inorganic ligands: chloride, nitrate, and acetate. The antibacterial effect of the Zn(II) complexes was studied against planktonic bacterial cells of Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) strains. The results showed a moderate biocide activity in both types of planktonic bacteria, which arises from the metal complexation to the Schiff base ligand. Importantly, we confirmed the crucial effect of the metal, with Zn(II) improving the activity of Cu(II) counterparts previously reported. On the other hand, the impact of the inorganic ligands was not significant for the antibacterial effect but was relevant for the complex solubility. Finally, as proof of concept of topical antibacterial formulation, we formulated an emulsion containing the most lipophilic Zn(II) complex and confirmed a sustained release for 24 h in a vertical cell diffusion assay. The promising activity of iminopyridine Zn(II) complexes is potentially worth exploring in more detailed studies.

Zinc-energized dynamic hydrogel accelerates bone regeneration via potentiating the coupling of angiogenesis and osteogenesis

Insufficient initial vascularization plays a pivotal role in the ineffectiveness of bone biomaterials for treating bone defects. Consequently, enhancing the angiogenic properties of bone repair biomaterials holds immense importance in augmenting the efficacy of bone regeneration. In this context, we have successfully engineered a composite hydrogel capable of promoting vascularization in the process of bone regeneration. To achieve this, the researchers first prepared an aminated bioactive glass containing zinc ions (AZnBg), and hyaluronic acid contains aldehyde groups (HA-CHO). The composite hydrogel was formed by combining AZnBg with gelatin methacryloyl (GelMA) and HA-CHO through Schiff base bonding. This composite hydrogel has good biocompatibility. In addition, the composite hydrogel exhibited significant osteoinductive activity, promoting the activity of ALP, the formation of calcium nodules, and the expression of osteogenic genes. Notably, the hydrogel also promoted umbilical vein endothelial cell migration as well as tube formation by releasing zinc ions. The results of in vivo study demonstrated that implantation of the composite hydrogel in the bone defect of the distal femur of rats could effectively stimulate bone generation and the development of new blood vessels, thus accelerating the bone healing process. In conclusion, the combining zinc-containing bioactive glass with hydrogels can effectively promote bone growth and angiogenesis, making it a viable option for the repair of critical-sized bone defects.

Effect of chronic cyclic heat stress and supplemented inorganic and organic zinc source levels on grow-finish pig growth performance and estimated body composition

Zinc (Zn) supplementation has proved to mitigate the effects of heat stress with varying effects evident with Zn source during acute heat events. However, the effects of Zn supplementation during long-term summer weather patterns have yet to be explored. Therefore, the objective of this study was to identify the effects of supplementation source and level of Zn to mitigate the negative effects of long-term, cyclic heat stress in finishing swine. Six hundred cross-bred pigs were housed under thermoneutral (TN) or cyclic heat (HS) conditions simulating summer heat with acute 3-d heat waves for a 70-d study. Thermoneutral conditions were 16.7 to 18.9 °C throughout the study. HS pigs were housed at the same temperature as TN from days 0 to 18, then 28 °C/24 °C for 12 h/12 h on days 18 to 21, followed by 30 °C/26.7 °C for 12 h/12 h on days 24 to 70, except during acute heat (32 to 33 °C/29 to 30 °C, 12 h/12 h) on days 21 to 24, 42 to 45, and 63 to 66. Treatments were arranged in a 2 × 6 factorial with main effects of environment (HS vs. TN) and dietary available Zn supplementation: (1) 50 mg/kg zinc oxide (ZnO), (2) 130 mg/kg ZnO, (3) 50 mg/kg of organic Zn (Availa Zn), (4) 50 mg/kg ZnO + 40 mg/kg organic Zn, (5) 50 mg/kg ZnO + 60 mg/kg organic Zn, and (6) 50 mg/kg ZnO + 80 mg/kg organic Zn. Pigs (5 pigs/pen) were blocked by initial body weight (72.2 kg) and randomly allotted to 1 of 12 temperature and diet treatment combinations across 10 replicates. Body weight and feed intake were determined at the beginning and end of each acute heat event. All pigs were ultrasonically scanned at the 10th rib (TR) to predict loin muscle area (LMA), backfat (BF), and percent lean. Data were analyzed by the MIXED procedure in SAS with pen as the experimental unit. At day 63, HS pigs were lighter (P < 0.05), had lower overall average daily gain (ADG; P < 0.05) and average daily feed intake (P < 0.05). A diet-by-environment interaction was observed for overall ADG (P < 0.05) with diet 5 HS pigs having a 3.9% reduction in ADG whereas diet 6 had 14.4% reduction in ADG, while under TN temperatures diet 6 had the greatest overall ADG of all treatments. Other diets were intermediate in their ADG under both HS and TN conditions. Pigs under HS had less BF at the TR (P < 0.05) and a smaller LMA (P < 0.05), and a greater calculated percent lean (P < 0.05). Our results indicate that a blend of supplemental Zn sources at 50/60 mg/kg may mitigate the reduction in growth performance due to HS. While not directly contrasted, the NRC requirement of 50 mg/kg Zn may be too low to optimize finishing pig growth performance under both TN and HS conditions.

Enhanced osteogenic and antibacterial properties of titanium implant surface modified with Zn-incorporated nanowires: Preclinical in vitro and in vivo investigations

OBJECTIVE

This study aimed to synthesize zinc-incorporated nanowires structure modified titanium implant surface (Zn-NW-Ti) and explore its superior osteogenic and antibacterial properties in vitro and in vivo.

MATERIALS AND METHODS

Zn-NW-Ti was synthesized via displacement reactions between zinc sulfate solutions and the titanium (Ti) surface, which was pretreated by hydrofluoric acid etching and hyperthermal alkalinization. The physicochemical properties of the Zn-NW-Ti surface were examined. Moreover, the biological effects of Zn-NW-Ti on MC3T3-E1 cells and its antibacterial property against oral pathogenic bacteria (Staphylococcus aureus, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) compared with sandblasted and acid-etched Ti (SLA-Ti) and nanowires modified Ti (NW-Ti) surface were assessed. Zn-NW-Ti and SLA-Ti modified implants were inserted into the anterior extraction socket of the rabbit mandible with or without exposure to the mixed bacterial solution (S. aureus, P. gingivalis, and A. actinomycetemcomitans) to investigate the osteointegration and antibacterial performance via radiographic and histomorphometric analysis.

RESULTS

The Zn-NW-Ti surface was successfully prepared. The resultant titanium surface appeared as a nanowires structure with hydrophilicity, from which zinc ions were released in an effective concentration range. The Zn-NW-Ti surface performed better in facilitating the adhesion, proliferation, and differentiation of MC3T3-E1 cells while inhibiting the colonization of bacteria compared with SLA-Ti and NW-Ti surface. The Zn-NW-Ti implant exhibited enhanced osseointegration in vivo, which was attributed to increased osteogenic activity and reduced bacterial-induced inflammation compared with the SLA-Ti implant.

CONCLUSIONS

The Zn-incorporated nanowires structure modified titanium implant surface exhibited improvements in osteogenic and antibacterial properties, which optimized osteointegration in comparison with SLA titanium implant surface.

Comparative efficacy of hydroxychloride and organic sources of zinc, copper, and manganese on egg production and concentration of trace minerals in eggs, plasma, and excreta in female broiler breeders from 42 to 63 weeks of age

Comparative efficacy of hydroxychloride (HC) and organic (OR) sources of Zn, Cu and Mn on performance of broiler breeders (BB) between 42 and 63 weeks of age (WOA) was investigated. A total of 408 ♀ Ross 708 and 48 ♂ Yield Plus cockerels were placed in pens (17 ♀ and 2 ♂) housed in 2 rooms (12 pens/room) and allocated to one of 2 diets in a completely randomized block design (n=12). The diets had similar nutrient specifications but differed in Zn, Cu, and Mn sources: 1) HO, a blend of 80% HC and 20% OR sources, and 2) OR, 100% OR sources. Birds were fed and managed according to breeder guidelines. The egg count was recorded daily and categorized as normal or abnormal. Egg yolk color, albumen height, Haugh unit, eggshell thickness, and eggshell breaking strength were assessed every 4 wk. Individual hen body weight (BW) was recorded at 5-wk intervals to determine BW uniformity. At 52 and 63 WOA, the eggs and excreta samples were collected. At the end of the trial, 4 hens per pen were bled for plasma concentration of trace minerals and organs (liver, gizzard, spleen, kidney, and thymus) weight. There were no interactions between source and age on any parameters (P > 0.05). There were no main effects of source on egg production, eggshell quality, BW, and organs weight (P > 0.05). Hens fed HO diets had darker yolk compared to those fed OR diets (P = 0.014). The concentration of Zn in the eggs of OR BB was higher (P = 0.022) than for HO birds. However, there were no dietary effects on the concentration of trace minerals in the egg, plasma, and excreta (P > 0.05). The results indicated that a mixture of HC and O as sources for Zn, Cu, and Mn was as effective as OR sources in supporting egg production, egg quality, and trace mineral utilization in broiler breeders.

The effect of a multicomponent oral care regimen on gingival inflammation: A randomized controlled clinical trial

BACKGROUND

Oral care regimens can be explored to improve oral health in patients with gingivitis. This study aimed to evaluate the efficacy of a multicomponent oral care regimen with a dual zinc plus arginine (DZA) toothpaste and cetylpyridinium chloride with zinc lactate (CPC + Zn) mouthwash in reducing gingival bleeding in patients with gingivitis.

METHODS

This randomized clinical trial included 94 participants with gingivitis who were randomized into two groups: the DZA/CPC + Zn group, which used a 1450-ppm fluoride toothpaste containing 0.96% zinc plus 1.5% arginine and a fluoride-containing mouthwash with 0.075% CPC and 0.28% zinc lactate, and the control group, which used a 1450-ppm fluoride toothpaste and a placebo mouthwash for 6 months. All participants were examined by a blinded examiner who measured the gingival index, plaque index, and gingival severity index. Data were analyzed using paired t test, independent t test, and analysis of covariance (ANCOVA).

RESULTS

Both groups presented statistically significant reductions in all clinical parameters compared to baseline. The DZA/CPC + Zn group exhibited significantly greater reductions in gingival index, gingival severity index, proximal gingival index, plaque index and proximal plaque index compared to the control group at 1, 3, and 6 months. Furthermore, DZA/CPC + Zn significantly decreased the percentage of patients with generalized gingivitis over a 6-month follow-up period. However, differences between the DZA/CPC + Zn and the control groups were not maintained after both groups established similar regimens with fluoride toothpaste.

CONCLUSION

The multicomponent oral care regimen consisting of DZA toothpaste and CPC + Zn mouthwash is effective in reducing gingival inflammation and supragingival biofilm in patients with gingivitis.

Detection of insulin oligomeric forms by a novel surface plasmon resonance-diffusion coefficient based approach

Insulin is commonly used to treat diabetes and undergoes aggregation at the site of repeated injections in diabetic patients. Moreover, aggregation is also observed during its industrial production and transport and should be avoided to preserve its bioavailability to correctly adjust glucose levels in diabetic patients. However, monitoring the effect of various parameters (pH, protein concentration, metal ions, etc.) on the insulin aggregation and oligomerization state is very challenging. In this work, we have applied a novel Surface Plasmon Resonance (SPR)-based experimental approach to insulin solutions at various experimental conditions, monitoring how its diffusion coefficient is affected by pH and the presence of metal ions (copper and zinc) with unprecedented sensitivity, precision, and reproducibility. The reported SPR method, hereby applied to a protein for the first time, besides giving insight into the insulin oligomerization and aggregation phenomena, proved to be very robust for determining the diffusion coefficient of any biomolecule. A theoretical background is given together with the software description, specially designed to fit the experimental data. This new way of applying SPR represents an innovation in the bio-sensing field and expanding the potentiality of commonly used SPR instruments well over the canonical investigation of biomolecular interactions.

Glycoprotein Matrix Zinc Exhibits Improved Absorption: A Randomized Crossover Trial

Biotransformation of minerals via glycosylation by microorganisms such as yeast and/or probiotics yields nutrients bound to a food matrix, resulting in increased bioavailability. The purpose of this study was to compare the effects of glycoprotein matrix-bound zinc (GPM) on absorption compared to inorganic zinc oxide. Sixteen participants ingested 11 mg of zinc as either GPM™ Soy-Free Zinc (GPM, Ashland, Kearny, NJ, USA) or zinc oxide (USP). Blood samples were taken at 0 (i.e., baseline), 30, 60, 90, 120, 180, 240, 300, 360, 420, and 480 min post-ingestion. GPM zinc concentrations were significantly higher at 120 min (p = 0.02; 12.4 ± 5.1 mcg/dL), 180 min (p = 0.002; 16.8 ± 5.1 mcg/dL), and 240 min (p = 0.007; 14.6 ± 5.1 mcg/dL) in comparison to USP zinc oxide. In addition, GPM zinc significantly increased iAUC by 40% (5840 ± 2684 vs. 4183 ± 1132 mcg/dL * 480 min, p = 0.02), and Cmax values were 10% higher in GPM compared to USP (148 ± 21 mcg/dL vs. 135 ± 17.5 mcg/dL, p = 0.08). Tmax was 12% slower in GPM compared to USP (112.5 ± 38.7 min vs. 127.5 ± 43.1 min); however, differences in Tmax failed to reach statistical significance (p = 0.28). Zinc bound to a glycoprotein matrix significantly increased absorption compared to zinc oxide.

Zinc, Copper, and Iron in Selected Skin Diseases

Trace elements are essential for maintaining the body's homeostasis, and their special role has been demonstrated in skin physiology. Among the most important trace elements are zinc, copper, and iron. A deficiency or excess of trace elements can be associated with an increased risk of skin diseases, so increasing their supplementation or limiting intake can be helpful in dermatological treatment. In addition, determinations of their levels in various types of biological material can be useful as additional tests in dermatological treatment. This paper describes the role of these elements in skin physiology and summarizes data on zinc, copper, and iron in the course of selected, following skin diseases: psoriasis, pemphigus vulgaris, atopic dermatitis, acne vulgaris and seborrheic dermatitis. In addition, this work identifies the potential of trace elements as auxiliary tests in dermatology. According to preliminary studies, abnormal levels of zinc, copper, and iron are observed in many skin diseases and their determinations in serum or hair can be used as auxiliary and prognostic tests in the course of various dermatoses. However, since data for some conditions are conflicting, clearly defining the potential of trace elements as auxiliary tests or elements requiring restriction/supplement requires further research.

The Development of Innovated Complex Process for Treatment of Old Flotation Tailings of Copper-Zinc Sulfide Ore

The possibility of selective Cu and Zn leaching from the sample of old pyrite tailings, which is one of the most widespread types of solid waste forming during non-ferrous metal production, using sulfuric acid solutions and water was studied. It was shown that water leaching provided selective extraction of Cu and Zn and comparatively low iron ion extraction. At the same time, acid leaching provided the obtainment of pregnant solutions with high ferric ion concentration, which can be used for oxidative leaching of substandard copper concentrates. Water and acid leaching also provided increased Au recovery by cyanidation. The results suggest that acid leaching can be an effective approach for processing old flotation tailings, which allows the extraction of base metals from these wastes and treating flotation tailings for subsequent cyanidation. Effective flotation treatment methods should also provide environmental load reduction, which is caused by the long-term storage of metal-bearing wastes.

Zinc alleviates thermal stress-induced damage to the integrity and barrier function of cultured chicken embryonic primary jejunal epithelial cells via the MAPK and PI3K/AKT/mTOR signaling pathways

Zinc (Zn) could alleviate the adverse effect of high temperature (HT) on intestinal integrity and barrier function of broilers, but the underlying mechanisms remain unclear. We aimed to investigate the possible protective mechanisms of Zn on primary cultured broiler jejunal epithelial cells exposed to thermal stress (TS). In Exp.1, jejunal epithelial cells were exposed to 40℃ (normal temperature, NT) and 44℃ (HT) for 1, 2, 4, 6, or 8 h. Cells incubated for 8 h had the lowest transepithelial resistance (TEER) and the highest phenol red permeability under HT. In Exp.2, the cells were preincubated with different Zn sources (Zn sulfate as iZn and Zn proteinate with the moderate chelation strength as oZn) and Zn supplemental levels (50 and 100 µmol/L) under NT for 24 h, and then continuously incubated under HT for another 8 h. TS increased phenol red permeability, lactate dehydrogenase (LDH) activity and p-PKC/PKC level, and decreased TEER, cell proliferation, mRNA levels of claudin-1, occludin, zona occludens-1 (ZO-1), PI3K, AKT and mTOR, protein levels of claudin-1, ZO-1 and junctional adhesion molecule-A (JAM-A), and the levels of p-ERK/ERK, p-PI3K/PI3K and p-AKT/AKT. Under HT, oZn was more effective than iZn in increasing TEER, occludin, ZO-1, PI3K, and AKT mRNA levels, ZO-1 protein level, and p-AKT/AKT level; supplementation with 50 μmol Zn/L was more effective than 100 μmol Zn/L in increasing cell proliferation, JAM-A, PI3K, AKT, and PKC mRNA levels, JAM-A protein level, and the levels of p-ERK/ERK and p-PI3K/PI3K; furthermore, supplementation with 50 μmol Zn/L as oZn had the lowest LDH activity, and the highest ERK, JNK-1, and mTOR mRNA levels. Therefore, supplemental Zn, especially 50 μmol Zn/L as oZn, could alleviate the TS-induced integrity and barrier function damage of broiler jejunal epithelial cells possibly by promoting cell proliferation and tight junction protein expression via the MAPK and PI3K/AKT/mTOR signaling pathways.

Serum Levels of Copper and Zinc and Survival in Breast Cancer Patients

There is emerging interest in the relationship between several serum micronutrients and the prognosis of patients with breast cancer. The relationship between serum zinc and copper levels and breast cancer prognosis is unclear. In our study, we included 583 patients with breast cancer diagnosed between 2008 and 2015 in the region of Szczecin, Poland. In a blood sample obtained before treatment, serum zinc and copper levels were quantified by mass spectroscopy. Each patient was assigned to one of four categories (quartiles) based on the distribution of the elements in the entire cohort. Patients were followed from diagnosis to death over a mean of 10.0 years. The 10-year overall survival was 58.3% for women in the highest and 82.1% for those in the lowest quartile of serum copper/zinc ratio (p < 0.001). The multivariate hazard ratio (HR) for breast cancer death was 2.07 (95% CI 1.17-3.63; p = 0.01) for patients in the highest quartile of serum copper/zinc ratio compared to those in the lowest. There is evidence that the serum zinc level and copper/zinc ratio provide an independent predictive value for overall survival and breast cancer-specific survival after breast cancer diagnosis.

Zamzam Water Mitigates Cardiac Toxicity Risk through Modulation of GUT Microbiota and the Renin-angiotensin System

BACKGROUND

Cardiovascular diseases (CVDs) continue to exert a substantial global influence in specific areas due to population growth, aging, microbiota, and genetic/environmental factors. Drinking water has a strong impact on the health of an individual. Further, emerging evidence has highlighted the therapeutic potential and benefits of Zamzam water (Zam).

OBJECTIVE

We investigated the influence of Zam on doxorubicin-induced cardiac toxicity, elucidating its consequential effects on GUT microbiota dysbiosis and hepatic and renal functions.

METHODS

Male rats were categorized into four groups: Group 1 as Normal control (NC), Group 2 as Zamzam control (ZC), Group 3 Disease control (DC) and Group 4 as Therapeutic control (DZ) treated with Zam against doxorubicin-induced disease at a dose of 1mg/kg boy weight) intraperitoneally (i.p).

RESULTS

Significant dysbiosis in the composition of GM was observed in the DC group along with a significant decrease (p < 0.05) in serum levels of Zinc, interleukin-10 (IL-10), IL-6 and Angiotensin II (Ang II), while C-reactive protein (CRP), fibrinogen, and CKMB increased significantly (restoration of Zinc ions (0.72 ± 0.07 mcg/mL) compared to NC. Treatment with Zamzam exhibited a marked abundance of 18-times to 72% in Romboutsia, a genus of firmicutes, along with lowering of Proteobacteria in DZ followed by significant restoration of Zinc ions (0.72 ± 0.07 mcg/mL), significant (p ˂ 0.05) reduction in CRP (7.22 ± 0.39 mg/dL), CKMB (118.8 ± 1.02 U/L) and Fibrinogen (3.18 ± 0.16 mg/dL), significant (p < 0.05) increase in IL-10 (7.22 ± 0.84 pg/mL) and IL-6 (7.18 ± 0.40 pg/ml), restoration of Ang II (18.62 ± 0.50 nmol/mL/min), marked increase in renin with normal myocyte architecture and tissue orientation of kidney, and restoration of histological architecture of hepatocyte.

CONCLUSION

Zam treatment mitigated cardiac toxicity risk through the modulation of GUT microbiota and the renin-angiotensin system and tissue histology effectively.

Abrasive Wear Behavior of Batch Hot-Dip Galvanized Coatings

In recent decades, batch hot-dip galvanized (HDG) steel has proven itself in practical applications due to the good corrosion resistance of its components. Despite the importance of the mechanical-load-bearing capacity of these coatings, the wear behavior has, so far, only been investigated very sporadically and not systematically, so a quantification of the wear behavior and statements on the mechanisms are vague. Therefore, two body wear tests with bonded abrasive grain were carried out. Varying the friction rolls, load, and total number of cycles, the wear behavior was investigated. The mass loss and the layer thickness reduction were measured at different intervals. After the test, the microstructure in the cross-section and the hardness according to Vickers (0.01 HV) were evaluated. The results showed that the wear behavior of HDG coatings against abrasive loads can be characterized with the selected test conditions. Initially, the applied load removed the soft η-phase. As the total number of cycles increases, the η- and ζ-phases deform plastically, resulting in a lower mass reduction compared to that expected from the measured layer thickness. The characteristic structure of a batch HDG coating with hard intermetallic Zn-Fe phases and an outer pure zinc phase has demonstrated effective resistance to abrasion.

Contribution of Beef to Key Nutrient Intakes and Nutrient Adequacy in Pregnant and Lactating Women: NHANES 2011-2018 Analysis

Beef is an important source of high-quality protein and several micronutrients, including iron, zinc, and B-vitamins. The objective was to assess the association of beef intake with nutrient intake and adequacy among pregnant and lactating women using 24-h dietary recall data. Usual intakes from foods were determined with the National Cancer Institute (NCI) method and % population below Estimated Average Requirement (EAR) or above Adequate Intake (AI) were estimated. A high proportion of pregnant and lactating women had inadequate intakes for vitamin D (94%), vitamin E (82%), vitamin C (52%), and vitamin A (50%), magnesium (35%), folate (31%), zinc (25%), and vitamin B6 (22%); only 4% and 35% met AI for choline and potassium, respectively. About 67% of pregnant and lactating women were beef consumers, consuming 49 g beef/day. Beef consumers had higher intakes (p < 0.05) of energy, protein, calcium, iron, phosphorus, selenium, sodium, zinc, thiamin, riboflavin, and niacin, and a higher proportion (p < 0.05) met nutrient recommendations for protein, calcium, iron, zinc, thiamin, riboflavin, niacin, vitamin B6, and vitamin B12 compared to non-consumers. In conclusion, pregnant and lactating women generally have inadequate nutrient intakes from their diets. Beef consumers have higher intakes and adequacy for certain nutrients, many of which are inherently available in beef or in foods eaten with beef.

ZIP transporters-regulated Zn2+ homeostasis: A novel determinant of human diseases

As an essential trace element for organisms, zinc participates in various physiological processes, such as RNA transcription, DNA replication, cell proliferation, and cell differentiation. The destruction of zinc homeostasis is associated with various diseases. Zinc homeostasis is controlled by the cooperative action of zinc transporter proteins that are responsible for the influx and efflux of zinc. Zinc transporter proteins are mainly categorized into two families: Zrt/Irt-like protein (SLC39A/ZIP) family and zinc transporter (SLC30A/ZNT) family. ZIP transporters contain 14 members, namely ZIP1-14, which can be further divided into four subfamilies. Currently, ZIP transporters-regulated zinc homeostasis is one of the research hotspots. Cumulative evidence suggests that ZIP transporters-regulated zinc homeostasis may cause physiological dysfunction and contribute to the onset and progression of diverse diseases, such as cancers, neurological diseases, and cardiovascular diseases. In this review, we initially discuss the structure and distribution of ZIP transporters. Furthermore, we comprehensively review the latest research progress of ZIP transporters-regulated zinc homeostasis in diseases, providing a new perspective into new therapeutic targets for treating related diseases.

Zinc Supplementation Trial in Pediatric Chronic Kidney Disease: Effects on Circulating FGF-23 and Klotho

Background

Zinc status, its role in bone metabolism and efficacy of deficiency correction has not been well studied in children with chronic kidney disease (CKD).

Objectives

The primary objective was to investigate whether 3 months of oral zinc supplementation corrects zinc deficiency in children with CKD who have native or transplanted kidneys. The secondary objective was to compare circulating intact FGF-23 (iFGF-23), c-terminal FGF-23 (cFGF-23), and Klotho between zinc-sufficient and zinc-deficient children with CKD and to assess the relationship between circulating zinc, iFGF-23, cFGF-23, Klotho, bone biomarkers, copper, and phosphate excretion pre-supplementation and post-supplementation of zinc.

Methods

Forty-one children (25 male and 16 female, age 12.94 ± 4.13 years) with CKD in native or transplanted kidneys were recruited through 2 pediatric nephrology divisions in Ontario, Canada. Of those, 14 patients (9 native CKD, 5 transplant CKD) with identified zinc deficiency (64% enrollment rate) received zinc citrate supplement for 3 months: 10 mg orally once (4-8 years) or twice (9-18 years) daily.

Results

Zinc deficiency (plasma concentration < 11.5 µmol/L) was found in 22 patients (53.7%). A linear regression model suggested that zinc concentration reduced by 0.026 µmol/L (P = .04) for every 1-unit of estimated glomerular filtration rate (eGFR) drop. Zinc deficiency status was associated with higher serum iFGF-23; however, this was predominantly determined by the falling GFR. Zinc deficient and sufficient children had similar circulating c-FGF-23 and alpha-Klotho. Normalization of plasma zinc concentration was achieved in 8 (5 native CKD and 3 transplant CKD) out of 14 treated patients rising from 10.04 ± 1.42 to 12.29 ± 3.77 μmol/L (P = .0038). There were no significant changes in other biochemical measures in all treated patients. A statistically significant (P = .0078) rise in c-FGF-23 was observed only in a subgroup of 11 children treated with zinc but not receiving calcitriol.

Conclusions

Zinc status is related to kidney function and possibly connected to bone metabolism in patients with CKD. However, it plays a minor role in fine-tuning various metabolic processes. In this exploratory non-randomized study, 3 months supplementation with zinc corrected deficiency in just over half of patients and only modestly affected bone metabolism in asymptomatic CKD patients.

Timing of dietary zinc additions during gestation for improved piglet survival

The objectives of this study were to determine a practical approach to feeding elevated dietary zinc (Zn) to gestating sows in a commercial setting and to confirm preweaning mortality could be reduced by feeding high Zn to sows during different periods of gestation. The study was conducted at a commercial sow farm in the upper Midwest. Mixed parity sows (n = 267) over three consecutive weekly farrowing groups (sows farrowing within 1 wk) were assigned randomly to one of the three dietary treatments within parity. Treatments consisted of: (1) control sows fed a corn-soybean meal diet containing 206 mg/kg total supplemental Zn supplied by zinc hydroxychloride; (2) breed-to-farrow: as control + 147 mg/kg supplemental Zn as ZnSO4 (353 mg/kg total supplemental Zn) fed from 5 d after breeding to farrowing; and (3) day 110-to-farrow: as control fed from breeding to farrowing + 4,079 mg/kg supplemental Zn as ZnSO4 (4,285 mg/kg total supplemental Zn) starting day 110 of gestation until farrowing. At farrowing, individual piglets were weighed and identified within 12 h of birth. Data were analyzed using PROC GLIMMIX of SAS and the model considered the fixed effect of dietary treatment and random effect of farrowing group. Dietary treatments did not affect number of total pigs born per litter. For breed-to-farrow sows, there was an increase in the percentage of pigs born alive compared to sows fed the control and day 110-to-farrow treatments (P < 0.001). The number of stillborn pigs expressed as a percentage of total litter size at birth decreased for breed-to-farrow sows (P < 0.001) compared with control or day 110-to-farrow sows. Mortality of low birth weight piglets from birth to weaning did not differ among dietary treatments (P = 0.305); however, a trend for decreasing post-natal mortality (P = 0.068) of normal birth weight pigs was observed for pigs born to sows fed elevated Zn 5 d before farrowing. In conclusion, feeding elevated Zn to sows throughout gestation increased the proportion of pigs born alive suggesting that elevated gestational Zn intake makes piglets more robust to endure the stresses of farrowing and decreases intrapartum mortality. Under the conditions of this study, elevated Zn intake of sows did not influence piglet post-natal survival. However, feeding high zinc throughout gestation may decrease piglet mortality during the parturition process.

Restricted glycolysis is a primary cause of the reduced growth rate of zinc-deficient yeast cells

Zinc is required for many critical processes, including intermediary metabolism. In Saccharomyces cerevisiae, the Zap1 activator regulates the transcription of ∼80 genes in response to Zn supply. Some Zap1-regulated genes are Zn transporters that maintain Zn homeostasis, while others mediate adaptive responses that enhance fitness. One adaptive response gene encodes the 2-cysteine peroxiredoxin Tsa1, which is critical to Zn-deficient (ZnD) growth. Depending on its redox state, Tsa1 can function as a peroxidase, a protein chaperone, or a regulatory redox sensor. In a screen for possible Tsa1 regulatory targets, we identified a mutation (cdc19S492A) that partially suppressed the tsa1Δ growth defect. The cdc19S492A mutation reduced activity of its protein product, pyruvate kinase isozyme 1 (Pyk1), implicating Tsa1 in adapting glycolysis to ZnD conditions. Glycolysis requires activity of the Zn-dependent enzyme fructose-bisphosphate aldolase 1, which was substantially decreased in ZnD cells. We hypothesized that in ZnD tsa1Δ cells, the loss of a compensatory Tsa1 regulatory function causes depletion of glycolytic intermediates and restricts dependent amino acid synthesis pathways, and that the decreased activity of Pyk1S492A counteracted this depletion by slowing the irreversible conversion of phosphoenolpyruvate to pyruvate. In support of this model, supplementing ZnD tsa1Δ cells with aromatic amino acids improved their growth. Phosphoenolpyruvate supplementation, in contrast, had a much greater effect on growth rate of WT and tsa1Δ ZnD cells, indicating that inefficient glycolysis is a major factor limiting yeast growth. Surprisingly however, this restriction was not primarily due to low fructose-bisphosphate aldolase 1 activity, but instead occurs earlier in glycolysis.

Zinc contents in foods and estimates of dietary intakes in Guangzhou, Guangdong Province, China

Zinc is one of human essential metals. In this study, 101 kinds of daily food for residents, including vegetables, aquatic food, meat, fruits, rice and cereal products, pulse food, dairy products and eggs, were collected at various agricultural markets and supermarkets in Guangzhou city, China, and their zinc contents were determined. The results showed oyster is most abundant in zinc (703.5 ± 25.6 mg/kg), followed by high-zinc milk powder (58.63 ± 0.90 mg/kg), pulse food, mutton, beef and pig liver with zinc contents above 30 mg/kg. The zinc contents of rice and cereal products, milk powder, poultry, pork, some aquatic food and eggs are also relatively high (>10 mg/kg), while vegetables and fruits have zinc contents significantly below 10 mg/kg. The daily zinc intake per person was determined by considering the zinc content of various food types and the dietary habits of specific demographic groups, resulting in 12.3 mg/day for the normal person, 11.2 mg/day for low-income individual, 12.3 mg/day for middle-income individual, 13.3 mg/day for high-income individual, 10.2 mg/day for older individual, 12.9 mg/day for factory worker, 11.5 mg/day for college student, and 8.4 mg/day for kindergarten child. The reference values of zinc intake recommended by the Chinese Nutrition Society were used to evaluate the zinc intake of Guangzhou residents, showing that the residents' zinc intake is generally sufficient and not necessary to use zinc supplementation. Income, age and occupation could have posed influence on dietary intake of zinc.

Ameliorative effects of zinc and vitamin E against phthalates-induced reproductive toxicity in male rats

OBJECTIVE

Phthalates (PEs) could cause reproductive harm to males. A mixture of three widely used PEs (MPEs) was used to investigate the ameliorative effects of zinc (Zn) and vitamin E (VE) against male reproductive toxicity.

METHODS

Fifty male SD rats were randomly divided into five groups (n = 10). Rats in MPEs group were orally treated with 160 mg/kg/d MPEs, while rats in MPEs combined Zn and/or VE groups were treated with 160 mg/kg/d MPEs plus 25 mg/kg/d Zn and/or 25 mg/kg/d VE. After intervention for 70 days, it's was measured of male reproductive organs' weight, histopathological observation of sperms and testes, serum hormones, PIWI proteins and steroidogenic proteins.

RESULTS

Compared with control, anogenital distance, testes weight, epididymides weight, and sex hormones were significantly decreased, while the sperm malformation rate was markedly increased in MPEs group (p < .05); the testicular tissues were injured in MPEs group with disordered and decreased spermatids, and arrested spermatogenesis. PIWIL1, PIWIL2, StAR, CYP11A1 and CYP19A1 were down-regulated in MPEs group (p < .05). However, the alterations of these parameters were restored in MPEs combined Zn and/or VE groups (p < .05).

CONCLUSION

Zn and/or VE improved steroid hormone metabolism, and inhibited MPEs' male reproductive toxicity.

The effect of micronutrient on thyroid cancer risk: a Mendelian randomization study

Background

The effect of micronutrients on thyroid cancer has been studied in observational studies, however, the cause of relationships has not yet been determined. Thyroid cancer was the subject of a Mendelian randomization (MR) analysis of micronutrients. Aimed to determine whether micronutrient intake has a causal impact on the chance of developing thyroid cancer.

Methods

We used a Mendelian randomization (MR) analysis with two samples. Our circulation levels of Cu, Ir, Zn, Ca, VD, and VC were reflected by genetic variations reported from GWAS in individuals of European ancestry. For the GWAS outcome of thyroid cancer. Sensitivity studies that included MR-Egger, weighted median/mode tests, and a more open selection of variations at a genome-wide sub-significant threshold were added to our inverse-variance weighted (IVW) MR study.

Results

Using the IVW approach, we did not find evidence that any of the micronutrients to thyroid cancer (Cu: odds ratio [OR = 0.88, p = 0.41]; Zn: odds ratio [OR = 0.87, p = 0.40]; Ir: odds ratio [OR = 1.18, p = 0.39]; Ca: odds ratio [OR = 1.12, p = 0.43]; VC: odds ratio [OR = 0.95, p = 0.22]; VD: odds ratio [OR = 0.89, p = 0.04]). The heterogeneity (p > 0.05) and pleiotropy (p > 0.05) testing provided confirmatory evidence for the validity of our MR estimates.

Conclusion

This study does not provide evidence that supplementation with micronutrients including Cu, Ir, Zn, Ca, VD, and VC can prevent thyroid cancer.

Correlation between essential and toxic elements in maternal blood during early pregnancy and atrial septal defects/ventricular septal defects/patent ductus arteriosus in offspring

BACKGROUND

Congenital heart defects (CHDs) are the most common congenital malformation in the world. Recent studies have found that essential and toxic trace element levels may play a crucial role in the risk of neonatal malformation. However, the relationships between element levels in early pregnancy and CHD risk among humans remain unclear. This study investigates the association between maternal essential element (copper [Cu], zinc [Zn], calcium [Ca], manganese [Mg] and iron [Fe]) and toxic element (lead [Pb] and cadmium [Cd]) levels during early pregnancy and CHDs.

METHODS

A hospital-based case-control study was conducted, including 181 cases and 218 controls. Eligible participants underwent antenatal examination during gestational weeks 11-14 and trace element levels were detected by the atomic absorption method. Multi-variable logistic regression was used to examine the associations between the level of maternal trace elements and CHD risks.

RESULTS

Higher levels of Ca in early pregnancy were associated with lower risk of ASD/VSD risks. Moreover, higher Fe, Pb, and Cd levels in the first trimester were associated with higher risks of all CHD and the subtypes risks, and the tests for trend were significant (all p < .05). The restricted cubic spline analysis showed that there was a nonlinear inverted u-shaped dose-response relationship between levels of Zn, Pb, and Cd in the first trimester and risk of CHDs (non-linearity test p < .05).

CONCLUSIONS

A moderate increase in Zn and Ca levels and a decrease in Pb and Cd levels during early pregnancy are needed to reduce the incidence of CHDs in the Chinese population.

Evidence from an Avian Embryo Model that Zinc-Inducible MT4 Expression Protects Mitochondrial Function Against Oxidative Stress

BACKGROUND

Metallothioneins (MTs) have a strong affinity for zinc (Zn) and remain at a sufficiently high level in mitochondria. As the avian embryo is highly susceptible to oxidative damage and relatively easy to manipulate in a naturally closed chamber, it is an ideal model of the effects of oxidative stress on mitochondrial function. However, the protective roles and molecular mechanisms of Zn-inducible protein expression on mitochondrial function in response to various stressors are poorly understood.

OBJECTIVES

The study aimed to investigate the mechanisms by which Zn-induced MT4 expression protects mitochondrial function and energy metabolism subjected to oxidative stress using the avian embryo and embryonic primary hepatocyte models.

METHODS

First, we investigated whether MT4 expression alters mitochondrial function. Then, we examined the effects of Zn-induced MT4 overexpression and MT4 silencing on embryonic primary hepatocytes from breeder hens fed a normal Zn diet subjected to a tert-butyl hydroperoxide (BHP) oxidative stress challenge during incubation. In vivo, the avian embryos from hens fed the Zn-deficient and Zn-adequate diets were used to determine the protective roles of Zn-induced MT4 expression on the function of mitochondria exposed to oxidative stress induced by in ovo BHP injection.

RESULTS

An in vitro study revealed that Zn-induced MT4 expression reduced reactive oxygen species accumulation in primary hepatocytes. MT4 silencing exacerbated BHP-mediated mitochondrial dysfunction whereas Zn-inducible MT4 overexpression mitigated it. Another in vivo study disclosed that maternal Zn-induced MT4 expression protected mitochondrial function in chick embryo hepatocytes against oxidative stress by inhibiting the peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α)/peroxisome proliferators-activated receptor-γ (PPAR-γ) pathway.

CONCLUSION

This study underscores the potential protective roles of Zn-induced MT4 expression via the downregulation of the PGC-1α/PPAR-γ pathway on mitochondrial function stimulated by the stress challenge in the primary hepatocytes in an avian embryo model. Our findings suggested that Zn-induced MT4 expression could provide a new therapeutic target and preventive strategy for repairing mitochondrial dysfunction in disease.

Removing Heavy Metals: Cutting-Edge Strategies and Advancements in Biosorption Technology

This article explores recent advancements and innovative strategies in biosorption technology, with a particular focus on the removal of heavy metals, such as Cu(II), Pb(II), Cr(III), Cr(VI), Zn(II), and Ni(II), and a metalloid, As(V), from various sources. Detailed information on biosorbents, including their composition, structure, and performance metrics in heavy metal sorption, is presented. Specific attention is given to the numerical values of the adsorption capacities for each metal, showcasing the efficacy of biosorbents in removing Cu (up to 96.4%), Pb (up to 95%), Cr (up to 99.9%), Zn (up to 99%), Ni (up to 93.8%), and As (up to 92.9%) from wastewater and industrial effluents. In addition, the issue of biosorbent deactivation and failure over time is highlighted as it is crucial for the successful implementation of adsorption in practical applications. Such phenomena as blockage by other cations or chemical decomposition are reported, and chemical, thermal, and microwave treatments are indicated as effective regeneration techniques. Ongoing research should focus on the development of more resilient biosorbent materials, optimizing regeneration techniques, and exploring innovative approaches to improve the long-term performance and sustainability of biosorption technologies. The analysis showed that biosorption emerges as a promising strategy for alleviating pollutants in wastewater and industrial effluents, offering a sustainable and environmentally friendly approach to addressing water pollution challenges.

Zinc-doped hydroxyapatite as a pH responsive drug delivery system for anticancer drug 6-mercaptopurine

6-Mercaptopurine (6MP) is commonly used in the treatment of acute lymphoblastic leukemia as an important agent in maintenance therapy. Despite its therapeutic benefits, 6MP has some limitations during therapy. Taking into account the disadvantages during 6MP therapy, there is a great need to create an appropriate delivery system for this drug. 6MP contains in its structure nitrogen and sulfur atoms capable of forming coordination compounds with metal ions, for example zinc. Therefore, in this work, we prepared biocompatible hydroxyapatite (HAp) doped with zinc ions, and used it as a carrier for 6MP. Doped HAp has not been used as a carrier for this drug before. The work proved that the prepared carrier-drug system has a particle size of about 130 nm, which indicates its potential for intravenous delivery. In addition, in an acidic environment (imitating cancer cells), the carrier agglomerates allow targeted release of the drug. The drug is evenly distributed, which indicates that the doses released from it will always be comparable. The release of the drug in a neutral environment is long-lasting in controlled doses, whereas in an acidic environment it is immediate. The obtained results indicate the high potential of the material in both slow-release and cancer-targeted release of 6MP.

Zinc Alpha-2 Glycoprotein, Acylated Ghrelin, and Zinc Levels in Prediabetics

BACKGROUND/AIM

Prediabetic stages of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) exhibit differences in the sites of insulin resistance. Serum Zinc α-2 glycoprotein (ZAG), acylated ghrelin (AG), and zinc (Zn) levels can affect IFG, IGT, and diabetic glucose tolerance (DGT) differently. This study examined the importance of ZAG, AG, and serum Zn levels in prediabetic individuals with IFG, IGT, and DGT, compared to those with normal glucose levels.

PATIENTS AND METHODS

The study was conducted at İstanbul University Cerrahpaşa-Cerrahpaşa Faculty of Medicine. A total of n=151 volunteers were classified according to the WHO criteria for diabetes after undergoing an oral glucose tolerance test. Plasma and serum samples were measured by Inductively Coupled Plasma Optical Emission Spectroscopy, ELISA, and immunoassay.

RESULTS

Prediabetic conditions became more prominent with the decrease in ZAG levels. ZAG levels showed a negative correlation with acylated ghrelin and Homeostatic Model Assessment for assessing beta-cell function and insulin resistance. Zinc levels were significantly lower in DGT.

CONCLUSION

ZAG levels have regulatory effects on insulin resistance and plasma glucose levels are mediated by zinc and acylated ghrelin.

A systematic review of case series and clinical trials investigating systemic oral or injectable therapies for the treatment of vitiligo

AIMS AND OBJECTIVES

The purpose of this study is to investigate the effectiveness and safety of oral and injectable systemic treatments, such as methotrexate, azathioprine, cyclosporine, tofacitinib, baricitinib, corticosteroids, statins, zinc, apremilast, etc., for treating vitiligo lesions.

METHOD

Databases including PubMed, Scopus, and Web of Science were meticulously searched for studies spanning from 2010 to August 2023, focusing on systemic oral and injectable therapies for vitiligo, using comprehensive keywords and search syntaxes tailored to each database. Key data extracted included study design, treatment efficacy, patient outcomes, patient satisfaction, and safety profiles.

RESULTS

In a total of 42 included studies, oral mini-pulse corticosteroid therapy (OMP) was the subject of six studies (14.2%). Minocycline was the focus of five studies (11.9%), while methotrexate, apremilast, and tofacitinib each were examined in four studies (9.5%). Antioxidants and Afamelanotide were the subjects of three studies each (7.1%). Cyclosporine, simvastatin, oral zinc, oral corticosteroids (excluding OMP) and injections, and baricitinib were each explored in two studies (4.8%). Azathioprine, mycophenolate mofetil, and Alefacept were the subjects of one study each (2.4%).

CONCLUSION

Systemic treatments for vitiligo have been successful in controlling lesions without notable side effects. OMP, Methotrexate, Azathioprine, Cyclosporine, Mycophenolate mofetil, Simvastatin, Apremilast, Minocycline, Afamelanotide, Tofacitinib, Baricitinib, Antioxidants, and oral/injectable corticosteroids are effective treatment methods. However, oral zinc and alefacept did not show effectiveness.

Preventing and Controlling Zinc Deficiency Across the Life Course: A Call to Action

Through diverse roles, zinc determines a greater number of critical life functions than any other single micronutrient. Beyond the well-recognized importance of zinc for child growth and resistance to infections, zinc has numerous specific roles covering the regulation of glucose metabolism, and growing evidence links zinc deficiency with increased risk of diabetes and cardiometabolic disorders. Zinc nutriture is, thus, vitally important to health across the life course. Zinc deficiency is also one of the most common forms of micronutrient malnutrition globally. A clearer estimate of the burden of health disparity attributable to zinc deficiency in adulthood and later life emerges when accounting for its contribution to global elevated fasting blood glucose and related noncommunicable diseases (NCDs). Yet progress attenuating its prevalence has been limited due, in part, to the lack of sensitive and specific methods to assess human zinc status. This narrative review covers recent developments in our understanding of zinc's role in health, the impact of the changing climate and global context on zinc intake, novel functional biomarkers showing promise for monitoring population-level interventions, and solutions for improving population zinc intake. It aims to spur on implementation of evidence-based interventions for preventing and controlling zinc deficiency across the life course. Increasing zinc intake and combating global zinc deficiency requires context-specific strategies and a combination of complementary, evidence-based interventions, including supplementation, food fortification, and food and agricultural solutions such as biofortification, alongside efforts to improve zinc bioavailability. Enhancing dietary zinc content and bioavailability through zinc biofortification is an inclusive nutrition solution that can benefit the most vulnerable individuals and populations affected by inadequate diets to the greatest extent.

Zinc supplementation with polaprezinc was associated with improvements in albumin, prothrombin time activity, and hemoglobin in chronic liver disease

Zinc deficiency occurs in a variety of diseases, including chronic liver disease (CLD). We investigated the correlation between zinc levels and biochemical and hematological tests in CLD and the effect of zinc supplementation with polaprezinc on these values. The first study (Study 1) was a retrospective observational study of 490 patients with CLD not receiving zinc supplementation, with data available from September 2009 to August 2021. Univariate and multiple regression analysis showed that serum zinc levels correlated most strongly with albumin (Alb) and also significantly with prothrombin time activity (PT%) and hemoglobin (Hb). A subsequent study (Study 2) focused on patients with advanced CLD who used polaprezinc for more than 90 days between January 2005 and August 2021. Using a self-controlled design with the 6-month period prior to polaprezinc as the control period, comparisons showed that Alb (p<0.0001), PT% (p<0.0005), and Hb (p<0.01) were significantly improved in the polaprezinc-treated patients compared to the control group. In conclusion, serum zinc levels were correlated with serum Alb, Hb, and PT% in patients with CLD, and zinc supplementation with polaprezinc was associated with improvements in Alb, Hb, and PT% within at least 6 months.

Use of Hydrogel Electrolyte in Zn-MnO2 Rechargeable Batteries: Characterization of Safety, Performance, and Cu2+ Ion Diffusion

Achieving commercially acceptable Zn-MnO2 rechargeable batteries depends on the reversibility of active zinc and manganese materials, and avoiding side reactions during the second electron reaction of MnO2. Typically, liquid electrolytes such as potassium hydroxide (KOH) are used for Zn-MnO2 rechargeable batteries. However, it is known that using liquid electrolytes causes the formation of electrochemically inactive materials, such as precipitation Mn3O4 or ZnMn2O4 resulting from the uncontrollable reaction of Mn3+ dissolved species with zincate ions. In this paper, hydrogel electrolytes are tested for MnO2 electrodes undergoing two-electron cycling. Improved cell safety is achieved because the hydrogel electrolyte is non-spillable, according to standards from the US Department of Transportation (DOT). The cycling of "half cells" with advanced-formulation MnO2 cathodes paired with commercial NiOOH electrodes is tested with hydrogel and a normal electrolyte, to detect changes to the zincate crossover and reaction from anode to cathode. These half cells achieved ≥700 cycles with 99% coulombic efficiency and 63% energy efficiency at C/3 rates based on the second electron capacity of MnO2. Other cycling tests with "full cells" of Zn anodes with the same MnO2 cathodes achieved ~300 cycles until reaching 50% capacity fade, a comparable performance to cells using liquid electrolyte. Electrodes dissected after cycling showed that the liquid electrolyte allowed Cu ions to migrate more than the hydrogel electrolyte. However, measurements of the Cu diffusion coefficient showed no difference between liquid and gel electrolytes; thus, it was hypothesized that the gel electrolytes reduced the occurrence of Cu short circuits by either (a) reducing electrode physical contact to the separator or (b) reducing electro-convective electrolyte transport that may be as important as diffusive transport.

Utilization of a Histoplasma capsulatum zinc reporter reveals the complexities of fungal sensing of metal deprivation

Histoplasma capsulatum is a dimorphic fungal pathogen acquired via inhalation of soil-resident spores. Upon exposure to mammalian body temperatures, these fungal elements transform into yeasts that reside primarily within phagocytes. Macrophages (MΦ) provide a permissive environment for fungal replication until T cell-dependent immunity is engaged. MΦ activated by granulocyte macrophage colony stimulating factor (GM-CSF) induces metallothioneins (MTs) that bind zinc (Zn) and deprive yeast cells of labile Zn, thereby disabling fungal growth. Prior work demonstrated that the zinc transporter, ZRT2, was important for fungal survival in vivo. Hence, we constructed a yeast cell reporter strain that expresses green fluorescent protein (GFP) under control of the ZRT2 zinc-regulated promoter. This reporter accurately responds to a medium devoid of Zn. ZRT2 expression increased in GM-CSF, but not interferon-γ, stimulated MΦ. To examine the in vivo response, we infected mice with a reporter yeast strain and assessed ZRT2 expression at 0, 3, 7, and 14 days post-infection (dpi). ZRT2 expression minimally increased at 3 dpi and peaked at 7 dpi, corresponding with the onset of adaptive immunity. We discovered that the major MΦ populations that restrict Zn from the fungus are interstitial MΦ and exudate MΦ. Neutralizing GM-CSF blunted the control of infection but unexpectedly increased ZRT2 expression. This increase was dependent on another cytokine that activates MΦ to control H. capsulatum replication, M-CSF. These findings illustrate the reporter's ability to sense Zn in vitro and in vivo and correlate ZRT2 expression with GM-CSF and M-CSF activation of MΦ.IMPORTANCEPhagocytes use an arsenal of defenses to control the replication of Histoplasma yeasts, one of which is the limitation of trace metals. On the other hand, H. capsulatum combats metal restriction by upregulating metal importers such as the Zn importer ZRT2. This transporter contributes to H. capsulatum pathogenesis upon activation of adaptive immunity. We constructed a fluorescent ZRT2 transcriptional reporter to probe H. capsulatum Zn sensing during infection and exposed the role for M-CSF activation of macrophages when GM-CSF is absent. These data highlight the ways in which fungal pathogens sense metal deprivation in vivo and reveal the potential of metal-sensing reporters. The work adds a new dimension to study how intracellular pathogens sense and respond to the changing environments of the host.

Interactions between zinc and NRF2 in vascular redox signalling

Recent evidence highlights the importance of trace metal micronutrients such as zinc (Zn) in coronary and vascular diseases. Zn2+ plays a signalling role in modulating endothelial nitric oxide synthase and protects the endothelium against oxidative stress by up-regulation of glutathione synthesis. Excessive accumulation of Zn2+ in endothelial cells leads to apoptotic cell death resulting from dysregulation of glutathione and mitochondrial ATP synthesis, whereas zinc deficiency induces an inflammatory phenotype, associated with increased monocyte adhesion. Nuclear factor-E2-related factor 2 (NRF2) is a transcription factor known to target hundreds of different genes. Activation of NRF2 affects redox metabolism, autophagy, cell proliferation, remodelling of the extracellular matrix and wound healing. As a redox-inert metal ion, Zn has emerged as a biomarker in diagnosis and as a therapeutic approach for oxidative-related diseases due to its close link to NRF2 signalling. In non-vascular cell types, Zn has been shown to modify conformations of the NRF2 negative regulators Kelch-like ECH-associated Protein 1 (KEAP1) and glycogen synthase kinase 3β (GSK3β) and to promote degradation of BACH1, a transcriptional suppressor of select NRF2 genes. Zn can affect phosphorylation signalling, including mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinases and protein kinase C, which facilitate NRF2 phosphorylation and nuclear translocation. Notably, several NRF2-targeted proteins have been suggested to modify cellular Zn concentration via Zn exporters (ZnTs) and importers (ZIPs) and the Zn buffering protein metallothionein. This review summarises the cross-talk between reactive oxygen species, Zn and NRF2 in antioxidant responses of vascular cells against oxidative stress and hypoxia/reoxygenation.

AtIAR1 is a Zn transporter that regulates auxin metabolism in Arabidopsis thaliana

Root growth in Arabidopsis is inhibited by exogenous auxin-amino acid conjugates, and mutants resistant to one such conjugate [indole-3-acetic acid (IAA)-Ala] map to a gene (AtIAR1) that is a member of a metal transporter family. Here, we test the hypothesis that AtIAR1 controls the hydrolysis of stored conjugated auxin to free auxin through zinc transport. AtIAR1 complements a yeast mutant sensitive to zinc, but not manganese- or iron-sensitive mutants, and the transporter is predicted to be localized to the endoplasmic reticulum/Golgi in plants. A previously identified Atiar1 mutant and a non-expressed T-DNA mutant both exhibit altered auxin metabolism, including decreased IAA-glucose conjugate levels in zinc-deficient conditions and insensitivity to the growth effect of exogenous IAA-Ala conjugates. At a high concentration of zinc, wild-type plants show a novel enhanced response to root growth inhibition by exogenous IAA-Ala which is disrupted in both Atiar1 mutants. Furthermore, both Atiar1 mutants show changes in auxin-related phenotypes, including lateral root density and hypocotyl length. The findings therefore suggest a role for AtIAR1 in controlling zinc release from the secretory system, where zinc homeostasis plays a key role in regulation of auxin metabolism and plant growth regulation.

Evaluating dietary considerations in hidradenitis suppurativa: a critical examination of existing knowledge

Hidradenitis suppurativa (HS) is a chronic condition that can overwhelm patients, and the effectiveness of supplementary dietary treatments remains uncertain. The primary aim of this review is to explore the connection between diet and HS progression. However, it is imperative to note that the evidence supporting a substantial role of the diet in HS remains weak. Dietary alterations alone should not be considered independent solutions for managing HS. Medical therapy continues to be indispensable for adequate treatment. Research indicates that the Mediterranean lifestyle and diet may provide cost-effective and beneficial adjustments when combined with traditional therapies. Conversely, foods with a high glycemic index and dairy could worsen HS symptoms, conceivably through mechanisms linked to insulin resistance and inflammation. Zinc, known for its antioxidant properties, shows promise as an adjunct therapy. Moreover, evidence suggests a connection between vitamin D deficiency and HS severity, although the findings are inconclusive. Brewer's yeast-free diet, B12 supplementation, intermittent fasting, and reducing the intake of refined sugar and dairy merit further investigation. In conclusion, this review highlights the need for additional research because of the lack of standardized reporting of clinical effects in the studies under scrutiny. A deeper exploration of the pathophysiology focusing on dietary modifications and their potential associations with HS severity is essential. Furthermore, it is crucial to recognize that patients' willingness to experiment with new diets makes them vulnerable to fraudulent interventions, highlighting the importance of evidence-based dietary guidance.

Effect of daily zinc supplementation for 12 weeks on serum thyroid auto-antibody levels in children and adolescents with autoimmune thyroiditis - a randomized controlled trial

OBJECTIVES

To assess the effect of daily zinc supplementation for 12 weeks on thyroid auto-antibodies - thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), and oxidative stress in children with autoimmune thyroid disease (AITD) compared to standard therapy.

METHODS

This open-labeled, parallel, randomized controlled trial was done in a tertiary care teaching institute in south India. Children aged 3-18 years with AITD were randomized to receive 25 mg elemental zinc daily for 12 weeks or standard therapy alone. The change in thyroid function tests (thyroid stimulating hormone, free T3, free T4), thyroid auto-antibody (TPOAb, TgAb) titers, oxidative stress markers (glutathione peroxidase, malondialdehyde, superoxide dismutase, and total antioxidant capacity) were compared.

RESULTS

Forty children, 20 in each arm, were recruited in the study. We observed a female-to-male ratio of 7:1. Median duration of disease was 2 (0.25, 4.25) years. A total of 37 (92.5 %) children were hypothyroid, two hyperthyroid, and one euthyroid at enrolment. A total of 13 children (32.5 %) had associated co-morbidities, most commonly type 1 diabetes mellitus and systemic lupus erythematosus, three (7.5 %) each. We did not find any significant change in thyroid function tests, thyroid auto-antibody titers, and oxidative stress markers. However, the requirement of levothyroxine dose was significantly increased in the control arm, compared to the zinc group (p=0.03). Only four (20 %) children had minor adverse effects like nausea, metallic taste, and body ache.

CONCLUSIONS

Zinc supplementation did not have any effect on thyroid auto-antibodies and oxidative stress. Zinc-supplemented children did not require escalation in levothyroxine dose.

Protecting the Achilles heel: three FolE_I-type GTP-cyclohydrolases needed for full growth of metal-resistant Cupriavidus metallidurans under a variety of conditions

In Cupriavidus metallidurans and other bacteria, biosynthesis of the essential biochemical cofactor tetrahydrofolate (THF) initiates from guanosine triphosphate (GTP). This step is catalyzed by FolE_I-type GTP cyclohydrolases, which are either zinc-dependent FolE_IA-type or metal-promiscuous FolE_IB-type enzymes. As THF is also essential for GTP biosynthesis, GTP and THF synthesis form a cooperative cycle, which may be influenced by the cellular homeostasis of zinc and other metal cations. Metal-resistant C. metallidurans harbors one FolE_IA-type and two FolE_IB-type enzymes. All three proteins were produced in Escherichia coli. FolE_IA was indeed zinc dependent and the two FolE_IB enzymes metal-promiscuous GTP cyclohydrolases in vitro, the latter, for example, functioning with iron, manganese, or cobalt. Single and double mutants of C. metallidurans with deletions in the folE_I genes were constructed to analyze the contribution of the individual FolE_I-type enzymes under various conditions. FolE_IA was required in the presence of cadmium, hydrogen peroxide, metal chelators, and under general metal starvation conditions. FolE_IB1 was important when zinc uptake was impaired in cells without the zinc importer ZupT (ZIP family) and in the presence of trimethoprim, an inhibitor of THF biosynthesis. FolE_IB2 was needed under conditions of low zinc and cobalt but high magnesium availability. Together, these data demonstrate that C. metallidurans requires all three enzymes to allow efficient growth under a variety of conditions.IMPORTANCETetrahydrofolate (THF) is an important cofactor in microbial biochemistry. This "Achilles heel" of metabolism has been exploited by anti-metabolites and antibiotics such as sulfonamide and trimethoprim. Since THF is essential for the synthesis of guanosine triphosphate (GTP) and THF biosynthesis starts from GTP, synthesis of both compounds forms a cooperative cycle. The first step of THF synthesis by GTP cyclohydrolases (FolEs) is metal dependent and catalyzed by zinc- or metal-promiscuous enzymes, so that the cooperative THF and GTP synthesis cycle may be influenced by the homeostasis of several metal cations, especially that of zinc. The metal-resistant bacterium C. metallidurans needs three FolEs to grow in environments with both high and low zinc and cadmium content. Consequently, bacterial metal homeostasis is required to guarantee THF biosynthesis.

Resisting death by metal: metabolism and Cu/Zn homeostasis in bacteria

Metal ions such as zinc and copper play important roles in host-microbe interactions and their availability can drastically affect the survival of pathogenic bacteria in a host niche. Mechanisms of metal homeostasis protect bacteria from starvation, or intoxication, defined as when metals are limiting, or in excess, respectively. In this mini-review, we summarise current knowledge on the mechanisms of resistance to metal stress in bacteria, focussing specifically on the homeostasis of cellular copper and zinc. This includes a summary of the factors that subvert metal stress in bacteria, which are independent of metal efflux systems, and commentary on the role of small molecules and metabolic systems as important mediators of metal resistance.