Zinc and human disease

Evaluation of the Safety and Potential Benefits of Beetroot-Based Dietary Supplements According to Their Elemental Composition

The study aimed to assess the health value and safety associated with the consumption of the chosen 37 beetroot-based dietary supplements (DSs). An optimized and validated analytical procedure, using a method called microwave plasma atomic emission spectrometry (MP-AES), was developed to determine the profiles of 19 elements (Na, K, Fe, Ca, Pt, Zn, Cd, Cu, V, Co, Ni, Pb, Mo, Mg, Al, Mn, Sr, Cr, Ba) in the DSs. The products were assessed for compliance with the recommended daily doses for the chosen elements, and any deviations were identified. Results showed that powders constituted a richer source of elements than capsules and tablets. The exception was iron-enriched products, which provided the highest dose of Fe (3.75 to 25 mg/daily dose). Safety assessment was evaluated in 3 steps, including (1) the determination of levels of Al, Ba, Cd, and Pb; (2) comparison of their content with the permissible contamination limits; and (3) comparison of the weekly or monthly intake of Al and Cd with the provisional tolerable weekly (PTWI) or monthly (PTMI) intake, respectively. The content of Ba was evaluated because of the oral reference dose (RfD). Five products were significantly contaminated with Cd (4-134% of PTMI Cd), two with Al (11-12%), and three with Ba (1.085-1.331 µg/d.d.). Lead was not detected above the LOQ (0.035 mg/kg). Factor analysis was employed to differentiate between the pharmaceutical forms (capsules, tablets, and powders) and determine the origin of the powder contained in the capsules. These results highlight the importance of implementing more stringent control measures and regulatory changes in the DSs market to ensure consumer safety.

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.

Biochemical Markers of Zinc Nutrition

Zinc is an important trace element involved in the biochemical and physiological functions of the organism and is essential in the human body. It has been reported that 17.3% of people around the world are at risk of many diseases due to zinc deficiency, which has already affected people's healthy lives. Currently, mild zinc deficiency is difficult to diagnose early due to the lack of typical clinical manifestations, so finding zinc biomarkers is crucial for people's health. The present article reviews the main representative zinc biomarkers, such as body fluid zinc levels, zinc-dependent proteins, tissue zinc, and zinc-containing enzymes, to provide a reference for actively promoting the study of zinc nutritional status and early clinical diagnosis.

Intracellular Zn(II) induced turn-on fluorescence of an L-phenylalanine-derived pseudopeptide

A C2 symmetric L-phenylalanine-derived pseudopeptide has been synthesized for selective and sensitive recognition of Zn(II) ions in aqueous-organic media. The pseudopeptidic probes exhibit intracellular Zn(II) ion-sensing capabilities as demonstrated via live-cell fluorescence studies on RAW264.7 cells. Hence, we present a bioinspired pseudopeptide for potential biological applications involving intracellular Zn(II) ion detection.

A State-of-the-Science Review on Metal Biomarkers

PURPOSE OF REVIEW

Biomarkers are commonly used in epidemiological studies to assess metals and metalloid exposure and estimate internal dose, as they integrate multiple sources and routes of exposure. Researchers are increasingly using multi-metal panels and innovative statistical methods to understand how exposure to real-world metal mixtures affects human health. Metals have both common and unique sources and routes of exposure, as well as biotransformation and elimination pathways. The development of multi-element analytical technology allows researchers to examine a broad spectrum of metals in their studies; however, their interpretation is complex as they can reflect different windows of exposure and several biomarkers have critical limitations. This review elaborates on more than 500 scientific publications to discuss major sources of exposure, biotransformation and elimination, and biomarkers of exposure and internal dose for 12 metals/metalloids, including 8 non-essential elements (arsenic, barium, cadmium, lead, mercury, nickel, tin, uranium) and 4 essential elements (manganese, molybdenum, selenium, and zinc) commonly used in multi-element analyses.

RECENT FINDINGS

We conclude that not all metal biomarkers are adequate measures of exposure and that understanding the metabolic biotransformation and elimination of metals is key to metal biomarker interpretation. For example, whole blood is a good biomarker of exposure to arsenic, cadmium, lead, mercury, and tin, but it is not a good indicator for barium, nickel, and uranium. For some essential metals, the interpretation of whole blood biomarkers is unclear. Urine is the most commonly used biomarker of exposure across metals but it should not be used to assess lead exposure. Essential metals such as zinc and manganese are tightly regulated by homeostatic processes; thus, elevated levels in urine may reflect body loss and metabolic processes rather than excess exposure. Total urinary arsenic may reflect exposure to both organic and inorganic arsenic, thus, arsenic speciation and adjustment for arsebonetaine are needed in populations with dietary seafood consumption. Hair and nails primarily reflect exposure to organic mercury, except in populations exposed to high levels of inorganic mercury such as in occupational and environmental settings. When selecting biomarkers, it is also critical to consider the exposure window of interest. Most populations are chronically exposed to metals in the low-to-moderate range, yet many biomarkers reflect recent exposures. Toenails are emerging biomarkers in this regard. They are reliable biomarkers of long-term exposure for arsenic, mercury, manganese, and selenium. However, more research is needed to understand the role of nails as a biomarker of exposure to other metals. Similarly, teeth are increasingly used to assess lifelong exposures to several essential and non-essential metals such as lead, including during the prenatal window. As metals epidemiology moves towards embracing a multi-metal/mixtures approach and expanding metal panels to include less commonly studied metals, it is important for researchers to have a strong knowledge base about the metal biomarkers included in their research. This review aims to aid metals researchers in their analysis planning, facilitate sound analytical decision-making, as well as appropriate understanding and interpretation of results.

Zinc treatment reverses and anti-Zn-regulated miRs suppress esophageal carcinomas in vivo

Esophageal squamous cell carcinoma (ESCC) is a deadly disease with few prevention or treatment options. ESCC development in humans and rodents is associated with Zn deficiency (ZD), inflammation, and overexpression of oncogenic microRNAs: miR-31 and miR-21. In a ZD-promoted ESCC rat model with upregulation of these miRs, systemic antimiR-31 suppresses the miR-31-EGLN3/STK40-NF-κB-controlled inflammatory pathway and ESCC. In this model, systemic delivery of Zn-regulated antimiR-31, followed by antimiR-21, restored expression of tumor-suppressor proteins targeted by these specific miRs: STK40/EGLN3 (miR-31), PDCD4 (miR-21), suppressing inflammation, promoting apoptosis, and inhibiting ESCC development. Moreover, ESCC-bearing Zn-deficient (ZD) rats receiving Zn medication showed a 47% decrease in ESCC incidence vs. Zn-untreated controls. Zn treatment eliminated ESCCs by affecting a spectrum of biological processes that included downregulation of expression of the two miRs and miR-31-controlled inflammatory pathway, stimulation of miR-21-PDCD4 axis apoptosis, and reversal of the ESCC metabolome: with decrease in putrescine, increase in glucose, accompanied by downregulation of metabolite enzymes ODC and HK2. Thus, Zn treatment or miR-31/21 silencing are effective therapeutic strategies for ESCC in this rodent model and should be examined in the human counterpart exhibiting the same biological processes.

Metallobiology of Lactobacillaceae in the gut microbiome

Lactobacillaceae are a diverse family of lactic acid bacteria found in the gut microbiota of humans and many animals. These bacteria exhibit beneficial effects on intestinal health, including modulating the immune system and providing protection against pathogens, and many species are frequently used as probiotics. Gut bacteria acquire essential metal ions, like iron, zinc, and manganese, through the host diet and changes to the levels of these metals are often linked to alterations in microbial community composition, susceptibility to infection, and gastrointestinal diseases. Lactobacillaceae are frequently among the organisms increased or decreased in abundance due to changes in metal availability, yet many of the molecular mechanisms underlying these changes have yet to be defined. Metal requirements and metallotransporters have been studied in some species of Lactobacillaceae, but few of the mechanisms used by these bacteria to respond to metal limitation or excess have been investigated. This review provides a current overview of these mechanisms and covers how iron, zinc, and manganese impact Lactobacillaceae in the gut microbiota with an emphasis on their biochemical roles, requirements, and homeostatic mechanisms in several species.

Bio-Activated PEEK: Promising Platforms for Improving Osteogenesis through Modulating Macrophage Polarization

The attention on orthopedic biomaterials has shifted from their direct osteogenic properties to their osteoimmunomodulation, especially the modulation of macrophage polarization. Presently, advanced technologies endow polyetheretherketone (PEEK) with good osteoimmunomodulation by modifying PEEK surface characteristics or incorporating bioactive substances with regulating macrophage polarization. Recent studies have demonstrated that the fabrication of a hydrophilic surface and the incorporation of bioactive substances into PEEK (e.g., zinc, calcium, and phosphate) are good strategies to promote osteogenesis by enhancing the polarization of M2 macrophages. Furthermore, the modification by other osteoimmunomodulatory composites (e.g., lncRNA-MM2P, IL-4, IL-10, and chitosan) and their controlled and desired release may make PEEK an optimal bio-activated implant for regulating and balancing the osteogenic system and immune system. The purpose of this review is to comprehensively evaluate the potential of bio-activated PEEK in polarizing macrophages into M2 phenotype to improve osteogenesis. For this objective, we retrieved and discussed different kinds of bio-activated PEEK regarding improving osteogenesis through modulating macrophage polarization. Meanwhile, the relevant challenges and outlook were presented. We hope that this review can shed light on the development of bio-activated PEEK with more favorable osteoimmunomodulation.

Zinc in Human Health and Infectious Diseases

During the last few decades, the micronutrient zinc has proven to be an important metal ion for a well-functioning immune system, and thus also for a suitable immune defense. Nowadays, it is known that the main cause of zinc deficiency is malnutrition. In particular, vulnerable populations, such as the elderly in Western countries and children in developing countries, are often affected. However, sufficient zinc intake and homeostasis is essential for a healthy life, as it is known that zinc deficiency is associated with a multitude of immune disorders such as metabolic and chronic diseases, as well as infectious diseases such as respiratory infections, malaria, HIV, or tuberculosis. Moreover, the modulation of the proinflammatory immune response and oxidative stress is well described. The anti-inflammatory and antioxidant properties of zinc have been known for a long time, but are not comprehensively researched and understood yet. Therefore, this review highlights the current molecular mechanisms underlying the development of a pro-/ and anti-inflammatory immune response as a result of zinc deficiency and zinc supplementation. Additionally, we emphasize the potential of zinc as a preventive and therapeutic agent, alone or in combination with other strategies, that could ameliorate infectious diseases.

Single and Combined Associations of Plasma and Urine Essential Trace Elements (Zn, Cu, Se, and Mn) with Cardiovascular Risk Factors in a Mediterranean Population

Trace elements are micronutrients that are required in very small quantities through diet but are crucial for the prevention of acute and chronic diseases. Despite the fact that initial studies demonstrated inverse associations between some of the most important essential trace elements (Zn, Cu, Se, and Mn) and cardiovascular disease, several recent studies have reported a direct association with cardiovascular risk factors due to the fact that these elements can act as both antioxidants and pro-oxidants, depending on several factors. This study aims to investigate the association between plasma and urine concentrations of trace elements and cardiovascular risk factors in a general population from the Mediterranean region, including 484 men and women aged 18−80 years and considering trace elements individually and as joint exposure. Zn, Cu, Se, and Mn were determined in plasma and urine using an inductively coupled plasma mass spectrometer (ICP-MS). Single and combined analysis of trace elements with plasma lipid, blood pressure, diabetes, and anthropometric variables was undertaken. Principal component analysis, quantile-based g-computation, and calculation of trace element risk scores (TERS) were used for the combined analyses. Models were adjusted for covariates. In single trace element models, we found statistically significant associations between plasma Se and increased total cholesterol and systolic blood pressure; plasma Cu and increased triglycerides and body mass index; and urine Zn and increased glucose. Moreover, in the joint exposure analysis using quantile g-computation and TERS, the combined plasma levels of Zn, Cu, Se (directly), and Mn (inversely) were strongly associated with hypercholesterolemia (OR: 2.03; 95%CI: 1.37−2.99; p < 0.001 per quartile increase in the g-computation approach). The analysis of urine mixtures revealed a significant relationship with both fasting glucose and diabetes (OR: 1.91; 95%CI: 1.01−3.04; p = 0.046). In conclusion, in this Mediterranean population, the combined effect of higher plasma trace element levels (primarily Se, Cu, and Zn) was directly associated with elevated plasma lipids, whereas the mixture effect in urine was primarily associated with plasma glucose. Both parameters are relevant cardiovascular risk factors, and increased trace element exposures should be considered with caution.

Upper Gastrointestinal Cancer and Liver Cirrhosis

Simple Summary

There is a higher incidence rate of upper gastrointestinal cancer in those with liver cirrhosis. The contributing factors include gastric ulcers, congestive gastropathy, zinc deficiency, alcohol drinking, tobacco use and gut microbiota. Most of the de novo malignancies that develop after liver transplantation for cirrhotic patients are upper gastrointestinal cancers. The surgical risk of upper gastrointestinal cancers in cirrhotic patients with advanced liver cirrhosis is higher.

Abstract

The extended scope of upper gastrointestinal cancer can include esophageal cancer, gastric cancer and pancreatic cancer. A higher incidence rate of gastric cancer and esophageal cancer in patients with liver cirrhosis has been reported. It is attributable to four possible causes which exist in cirrhotic patients, including a higher prevalence of gastric ulcers and congestive gastropathy, zinc deficiency, alcohol drinking and tobacco use and coexisting gut microbiota. Helicobacter pylori infection enhances the development of gastric cancer. In addition, Helicobacter pylori, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans also contribute to the development of pancreatic cancer in cirrhotic patients. Cirrhotic patients (especially those with alcoholic liver cirrhosis) who undergo liver transplantation have a higher overall risk of developing de novo malignancies. Most de novo malignancies are upper gastrointestinal malignancies. The prognosis is usually poor. Considering the surgical risk of upper gastrointestinal cancer among those with liver cirrhosis, a radical gastrectomy with D1 or D2 lymph node dissection can be undertaken in Child class A patients. D1 lymph node dissection can be performed in Child class B patients. Endoscopic submucosal dissection for gastric cancer or esophageal cancer can be undertaken safely in selected cirrhotic patients. In Child class C patients, a radical gastrectomy is potentially fatal. Pancreatic radical surgery should be avoided in those with liver cirrhosis with Child class B or a MELD score over 15. The current review focuses on the recent reports on some factors in liver cirrhosis that contribute to the development of upper gastrointestinal cancer. Quitting alcohol drinking and tobacco use is important. How to decrease the risk of the development of gastrointestinal cancer in those with liver cirrhosis remains a challenging problem.

The Oxidative Balance Orchestrates the Main Keystones of the Functional Activity of Cardiomyocytes

This review is aimed at providing an overview of the key hallmarks of cardiomyocytes in physiological and pathological conditions. The main feature of cardiac tissue is the force generation through contraction. This process requires a conspicuous energy demand and therefore an active metabolism. The cardiac tissue is rich of mitochondria, the powerhouses in cells. These organelles, producing ATP, are also the main sources of ROS whose altered handling can cause their accumulation and therefore triggers detrimental effects on mitochondria themselves and other cell components thus leading to apoptosis and cardiac diseases. This review highlights the metabolic aspects of cardiomyocytes and wanders through the main systems of these cells: (a) the unique structural organization (such as different protein complexes represented by contractile, regulatory, and structural proteins); (b) the homeostasis of intracellular Ca²⁺ that represents a crucial ion for cardiac functions and E-C coupling; and (c) the balance of Zn²⁺, an ion with a crucial impact on the cardiovascular system. Although each system seems to be independent and finely controlled, the contractile proteins, intracellular Ca²⁺ homeostasis, and intracellular Zn²⁺ signals are strongly linked to each other by the intracellular ROS management in a fascinating way to form a "functional tetrad" which ensures the proper functioning of the myocardium. Nevertheless, if ROS balance is not properly handled, one or more of these components could be altered resulting in deleterious effects leading to an unbalance of this "tetrad" and promoting cardiovascular diseases. In conclusion, this "functional tetrad" is proposed as a complex network that communicates continuously in the cardiomyocytes and can drive the switch from physiological to pathological conditions in the heart.

Zinc and gut microbiota in health and gastrointestinal disease under the COVID-19 suggestion

Microelements represent an emerging resource for medicine and its preventive branch. Zinc is the second most abundant element in our organism with peculiar physiologic functions and pathophysiologic implications in systemic and gastrointestinal (GI) diseases. It interacts very often with gut microbiota (GM) and can affect natural course of GI diseases through a bidirectional relationship with intestinal bugs. We aimed to review literature data regarding zinc chemistry, role in health, and GI diseases in man with a special focus on its interaction with GM. We conducted a search on the main medical databases for original articles, reviews, meta-analyses, randomized clinical trials and case series using the following keywords and acronyms and their associations: zinc, microelements, gut microbiota, gut health, and COVID-19. Zinc has a rapid and simple metabolism and limited storage within our body. Its efficacy on immune system modulation reflects on improved response to pathogens, reduced inflammatory response, and improved atopic/allergic reactions. Zinc is also involved in cell cycle regulation (namely, apoptosis) with potential anti-cancerogenic effects. All these effects are in a "symbiotic" relationship with GM. Finally, zinc shows preliminary viral antireplicative effects. Zinc seems to gain more and more evidences on its efficacy in allergic, atopic and infectious diseases treatment, and prevention. COVID-19 can be the booster for research on future applications of zinc as perfect "postbiotic" in medicine.

Assessment of Urinary Lead (Pb) and Essential Trace Elements in Autism Spectrum Disorder: a Case-Control Study Among Preschool Children in Malaysia

Lead (Pb) is a heavy metal which is abundant in the environment and known to cause neurotoxicity in children even at minute concentration. However, the trace elements calcium (Ca), magnesium (Mg), zinc (Zn) and iron (Fe) are essential to children due to its protective effect on neurodevelopment. The primary objective of this study was to assess the role of Pb and trace elements in the development of autism spectrum disorder (ASD) among preschool children. A total of 81 ASD children and 74 typically developed (TD) children aged between 3 and 6 years participated in the study. Self-administered online questionnaires were completed by the parents. A first-morning urine sample was collected in a sterile polyethene urine container and assayed for Pb, Ca, Mg, Zn and Fe using an inductively coupled plasma mass spectrometry (ICP-MS). Comparisons between groups revealed that the urinary Pb, Mg, Zn and Fe levels in ASD children were significantly lower than TD children. The odds of ASD reduced significantly by 5.0% and 23.0% with an increment of every 1.0 μg/dL urinary Zn and Fe, respectively. Post interaction analysis showed that the odds of ASD reduced significantly by 11.0% and 0.1% with an increment of every 1.0 μg/dL urinary Zn and Pb, respectively. A significantly lower urinary Pb level in ASD children than TD children may be due to their poor detoxifying mechanism. Also, the significantly lower urinary Zn and Fe levels in ASD children may augment the neurotoxic effect of Pb.

Zinc ionophores: chemistry and biological applications

Zinc can play a pathophysiological role in several diseases and can interfere in key processes of microbial growth. This evidence justifies the efforts in applying Zinc ionophores to restore Zinc homeostasis and treat bacterial/viral infections such as coronavirus diseases. Zinc ionophores increase the intracellular concentration of Zinc ions causing significant biological effects. This review provides, for the first time, an overview of the applications of the main Zinc ionophores in Zinc deficiency, infectious diseases, and in cancer, discussing the pharmacological and coordination properties of the Zinc ionophores.

The Bioinorganic Chemistry of Mammalian Metallothioneins

The functions, purposes, and roles of metallothioneins have been the subject of speculations since the discovery of the protein over 60 years ago. This article guides through the history of investigations and resolves multiple contentions by providing new interpretations of the structure-stability-function relationship. It challenges the dogma that the biologically relevant structure of the mammalian proteins is only the one determined by X-ray diffraction and NMR spectroscopy. The terms metallothionein and thionein are ambiguous and insufficient to understand biological function. The proteins need to be seen in their biological context, which limits and defines the chemistry possible. They exist in multiple forms with different degrees of metalation and types of metal ions. The homoleptic thiolate coordination of mammalian metallothioneins is important for their molecular mechanism. It endows the proteins with redox activity and a specific pH dependence of their metal affinities. The proteins, therefore, also exist in different redox states of the sulfur donor ligands. Their coordination dynamics allows a vast conformational landscape for interactions with other proteins and ligands. Many fundamental signal transduction pathways regulate the expression of the dozen of human metallothionein genes. Recent advances in understanding the control of cellular zinc and copper homeostasis are the foundation for suggesting that mammalian metallothioneins provide a highly dynamic, regulated, and uniquely biological metal buffer to control the availability, fluctuations, and signaling transients of the most competitive Zn(II) and Cu(I) ions in cellular space and time.

Zinc Transporter 9 (SLC30A9) Expression Is Decreased in the Vaginal Tissues of Menopausal Women

Our aim was to compare zinc transporter (ZnT/SLC30A, and ZIP/SLC39A) expression between pre- and postmenopausal women in human vaginal tissues. Zinc transporter families are responsible for the maintenance of intracellular zinc concentrations. Zinc has significant effects on the extracellular matrix composition. Vaginal wall biopsies were obtained from seven premenopausal and seven postmenopausal women. mRNA expression of twenty-four zinc transporters was determined by quantitative real-time PCR. Zinc transporter expression at the protein level was assessed by immunohistochemistry. Student's t test and Mann-Whitney U test were used to compare data. ZnT4 and ZnT9 mRNA expression were significantly lower in postmenopausal women compared with premenopausal women (mean ± SD mRNA expression in relative units, 96.43 ± 140.61 vs. 410.59 ± 304.34, p = 0.03 and 0.62 ± 0.39 vs. 1.13 ± 0.31, p = 0.02). In addition, ZIP2, ZIP3, and ZIP6 mRNA expressions were significantly lower in postmenopausal women compared with premenopausal women (mean ± SD mRNA expression in relative units, 1.11 ± 0.61 vs. 2.29 ± 1.20, p = 0.04; 2.32 ± 1.90 vs. 15.82 ± 12.97, p = 0.02 and 1.10 ± 0.80 vs. 5.73 ± 4.72, p = 0.03). ZnT9 protein expression in the stratum spinosum was significantly lower in postmenopausal women (p = 0.012). Zinc transporters were expressed differentially in the vaginal tissues. ZnT9 expression was significantly lower in postmenopausal women compared with premenopausal women.

Poly(lactic acid)/Zinc/Alginate Complex Material: Preparation and Antimicrobial Properties

The aim of this study was to investigate an antimicrobial and degradable composite material consisting of melt-blown poly(lactic acid) nonwoven fabrics, alginate, and zinc. This paper describes the method of preparation and the characterization of the physicochemical and antimicrobial properties of the new fibrous composite material. The procedure consists of fabrication of nonwoven fabric and two steps of dip-coating modification: (1) impregnation of nonwoven samples in the solution of alginic sodium salt and (2) immersion in a solution of zinc (II) chloride. The characterization and analysis of new material included scanning electron microscopy (SEM), specific surface area (SSA), and total/average pore volume (BET). The polylactide/alginate/Zn fibrous composite were subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus), Gram-negative (Escherichia coli) bacterial strains, and the following fungal strains: Aspergillus niger van Tieghem and Chaetomium globosum. These results lay a technical foundation for the development and potential application of new composite as an antibacterial/antifungal material in biomedical areas.

Alcohol's Impact on the Gut and Liver

Alcohol is inextricably linked with the digestive system. It is absorbed through the gut and metabolised by hepatocytes within the liver. Excessive alcohol use results in alterations to the gut microbiome and gut epithelial integrity. It contributes to important micronutrient deficiencies including short-chain fatty acids and trace elements that can influence immune function and lead to liver damage. In some people, long-term alcohol misuse results in liver disease progressing from fatty liver to cirrhosis and hepatocellular carcinoma, and results in over half of all deaths from chronic liver disease, over half a million globally per year. In this review, we will describe the effect of alcohol on the gut, the gut microbiome and liver function and structure, with a specific focus on micronutrients and areas for future research.

Zinc Nutritional Status in a Series of Children with Chronic Diseases: A Cross-Sectional Study

BACKGROUND

Zinc is an essential trace element for the normal growth and development of human beings. The main objective was to evaluate the nutritional status of zinc and its association with nutritional indicators in a series of children with chronic diseases.

METHODS

The prevalence of patients with dietary zinc deficiency or deficit zinc intake (<80% DRI: dietary reference intake) was analyzed through prospective 72 h dietary surveys, and serum zinc deficiency or hypozincemia (≤70 µg/dL in children under 10 years of age in both sexes and in females older than 10 years and <74 μg/dL in males older than 10 years) was measured through atomic absorption spectrophotometry. The participants were classified according to their nutritional status by body mass index (BMI).

RESULTS

Mean serum zinc level in obese (87 µg/dL), undernourished (85 µg/dL), and eutrophic children (88 µg/dL) were normal, but in the undernutrition (60% DRI) and eutrophic (67% DRI) groups the mean dietary zinc intake was low compared to that in the obesity group (81% DRI). There were different associations between nutritional parameters, dietary zinc intake, and serum zinc. All patients with hypozincemia had dietary zinc deficiency.

CONCLUSIONS

In the whole series, 69% of participants showed a zinc intake lower than recommended and might be at high risk of zinc deficiency.

Zinc and Cadmium in the Aetiology and Pathogenesis of Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are inflammatory articular conditions with different aetiology, but both result in joint damage. The nutritionally essential metal zinc (Zn²⁺) and the non-essential metal cadmium (Cd²⁺) have roles in these arthritic diseases as effectors of the immune system, inflammation, and metabolism. Despite both metal ions being redox-inert in biology, they affect the redox balance. It has been known for decades that zinc decreases in the blood of RA patients. It is largely unknown, however, whether this change is only a manifestation of an acute phase response in inflammation or relates to altered availability of zinc in tissues and consequently requires changes of zinc in the diet. As a cofactor in over 3000 human proteins and as a signaling ion, zinc affects many pathways relevant for arthritic disease. How it affects the diseases is not just a question of zinc status, but also an issue of mutations in the many proteins that maintain cellular zinc homoeostasis, such as zinc transporters of the ZIP (Zrt-/Irt-like protein) and ZnT families and metallothioneins, and the multiple pathways that change the expression of these proteins. Cadmium interferes with zinc's functions and there is increased uptake under zinc deficiency. Remarkably, cadmium exposure through inhalation is now recognized in the activation of macrophages to a pro-inflammatory state and suggested as a trigger of a specific form of nodular RA. Here, we discuss how these metal ions participate in the genetic, metabolic, and environmental factors that lead to joint destruction. We conclude that both metal ions should be monitored routinely in arthritic disease and that there is untapped potential for prognosis and treatment.

The role of labile Zn2+ and Zn2+-transporters in the pathophysiology of mitochondria dysfunction in cardiomyocytes

An important energy supplier of cardiomyocytes is mitochondria, similar to other mammalian cells. Studies have demonstrated that any defect in the normal processes controlled by mitochondria can lead to abnormal ROS production, thereby high oxidative stress as well as lack of ATP. Taken into consideration, the relationship between mitochondrial dysfunction and overproduction of ROS as well as the relation between increased ROS and high-level release of intracellular labile Zn²⁺, those bring into consideration the importance of the events related with those stimuli in cardiomyocytes responsible from cellular Zn²⁺-homeostasis and responsible Zn²⁺-transporters associated with the Zn²⁺-homeostasis and Zn²⁺-signaling. Zn²⁺-signaling, controlled by cellular Zn²⁺-homeostatic mechanisms, is regulated with intracellular labile Zn²⁺ levels, which are controlled, especially, with the two Zn²⁺-transporter families; ZIPs and ZnTs. Our experimental studies in mammalian cardiomyocytes and human heart tissue showed that Zn²⁺-transporters localizes to mitochondria besides sarco(endo)plasmic reticulum and Golgi under physiological condition. The protein levels as well as functions of those transporters can re-distribute under pathological conditions, therefore, they can interplay among organelles in cardiomyocytes to adjust a proper intracellular labile Zn²⁺ level. In the present review, we aimed to summarize the already known Zn²⁺-transporters localize to mitochondria and function to stabilize not only the cellular Zn²⁺ level but also cellular oxidative stress status. In conclusion, one can propose that a detailed understanding of cellular Zn²⁺-homeostasis and Zn²⁺-signaling through mitochondria may emphasize the importance of new mitochondria-targeting agents for prevention and/or therapy of cardiovascular dysfunction in humans.

Effect of Zn Supplementation on Trace Element Status in Rats with Diet-Induced Non-alcoholic Fatty Liver Disease

The present study aimed to assess the effect of Zn supplementation on trace element levels in the liver, serum, and hair of rats with dietary-induced non-alcoholic fatty liver disease (NAFLD). A total of 26 3-month-old female Wistar rats were divided into four groups: control, NAFLD, Zn-supplemented (227 mg/L zinc as Zn sulfate Zn(SO)₄ dissolved in a drinking water), and NAFLD-Zn-supplemented. NAFLD was verified by histological assessment of liver samples. The serum was examined for routine biochemical parameters. Trace elements content was assessed using inductively coupled plasma mass spectrometry (ICP-MS). Zn treatment resulted in an improvement in liver weight and morphology. Dietary supplementation with Zn prevented NAFLD-induced decrease liver Co. The tendency to increase liver Fe in the Zn-treated group was observed. Zn treatment decreased hepatic Al and serum V levels. However, Zn administration did not affect NAFLD-induced I, Mn, and Se depletion in the liver. Hair Zn levels raised in Zn-supplemented groups. Conclusively, the results of the study indicate that Zn supplementation could have a beneficial effect in modulation of the altered trace element status and liver morphology. HIGHLIGHTS: •Zn treatment improved liver weight and morphology in rats with NAFLD. •Zn supplementation decreased liver Al in NAFLD. •Treatment by Zn prevented depletion of liver Co. •Zn decreased serum V and increased hair Zn levels. •No effect of Zn on NAFLD-induced hepatic I, Mn and Se depletion was observed.

The Role of Zinc in Selected Female Reproductive System Disorders

Zinc is an essential microelement that plays many important functions in the body. It is crucial for the regulation of cell growth, hormone release, immunological response and reproduction. This review focuses on its importance in the reproductive system of women of reproductive and postmenopausal ages, not including its well described role in pregnancy. Only recently, attention has been drawn to the potential role of zinc in polycystic ovary syndrome (PCOS), dysmenorrhea, or endometriosis. This review is mainly based on 36 randomized, controlled studies on reproductive, pre- and post-menopausal populations of women and on research trying to explain the potential impact of zinc and its supplementation in the etiology of selected female reproductive system disorders. In women with PCOS, zinc supplementation has a positive effect on many parameters, especially those related to insulin resistance and lipid balance. In primary dysmenorrhea, zinc supplementation before and during each menstrual cycle seems to be an important factor reducing the intensity of menstrual pain. On the other hand, little is known of the role of zinc in endometriosis and in postmenopausal women. Therefore, further studies explaining the potential impact of zinc and its supplementation on female reproductive system would be highly advisable and valuable.

Trace element deficiency is highly prevalent and associated with infection and mortality in patients with alcoholic hepatitis

BACKGROUND

Malnutrition is common in patients with alcohol-related liver disease and is associated with outcome in patients with alcoholic hepatitis. Trace elements (cobalt, copper, iron, selenium and zinc) are micronutrients essential for many cellular processes including antioxidant pathways. The prevalence and relevance of trace element deficiency is unknown in alcoholic hepatitis.

AIM

To determine the prevalence of trace element deficiency and its association with clinical outcomes in patients with alcoholic hepatitis.

METHODS

Serum was obtained from patients with alcoholic hepatitis, alcohol-related cirrhosis and healthy volunteers as part of clinical trials, cohort studies and a biobank. Trace element concentration was measured by inductively coupled plasma mass spectrometry. Association of trace element levels with development of infection within 90 days and mortality within 28 and 90 days was evaluated by multivariate logistic regression.

RESULTS

Sera from 302 patients with alcoholic hepatitis, 46 with alcohol-related cirrhosis and 15 healthy controls were analysed for trace element concentration. The prevalence of zinc deficiency (85%) and selenium deficiency (67%) in alcoholic hepatitis was higher than in alcohol-related cirrhosis (72% [p=0.04] and 37% [p<0.001], respectively). Zinc, selenium, copper and chromium were significantly different between groups. Iron deficiency was a predictor of development of infection within 90 days. Zinc deficiency was a predictor of mortality within 28 and 90 days.

CONCLUSION

Trace element deficiency in patients with alcoholic hepatitis is highly prevalent and associated with infection and mortality. Supplementation with selected trace elements may improve clinical outcomes in this patient group but further insight is required of their biological and clinical effects.

Evaluation of zinc sulfate mucoadhesive formulation on recurrent aphthous stomatitis: a randomized double-blind, placebo-controlled clinical trial

BACKGROUND

Recurrent aphthous stomatitis (RAS) is a common lesion that affects the oral mucosa. There are several methods to treat RAS, including systemic and topical formulations. This study was conducted to evaluate the anti-inflammatory effect of topical zinc sulfate and its efficacy in the treatment of RAS.

METHODS

A double-blind randomized clinical trial was conducted on 46 patients with RAS. They were randomly assigned into two groups to receive a zinc sulfate mucoadhesive tablet or placebo for 7 days. The pain severity was measured at baseline and daily while the diameter of the lesion was measured at baseline and on days 3, 5, and 7. The obtained data were analyzed in SPSS V.16.

RESULTS

There was no significant difference in the mean diameter of lesions and pain at baseline between the two groups (P = 0.643 and P = 0.842, respectively). However, on the third, fifth, and seventh days of the study, the diameter of the lesion significantly reduced in the intervention group (P = 0.001) and the pain intensity became significantly different between groups from the fourth day of the study (P = 0.001).

CONCLUSION

Zinc sulfate mucoadhesive tablet was effective in recovery and reducing the pain and diameter of the aphthous lesion and could be considered for the treatment of RAS.

TRIAL REGISTRATION

Evaluation of the effectiveness of zinc sulfate mucoadhesive tablet in the improvement of recurrent aphthous stomatitis (RAS), IRCT20151109024975N9. Registered August 1, 2018, https://en.irct.ir/trial/32423 . This project was registered by the Iranian Registry of Clinical Trials ( http://www.irct.ir ). The IRCT ID was IRCT20151109024975N9.

Growth Modulatory Role of Zinc in Prostate Cancer and Application to Cancer Therapeutics

Zinc is a group IIB heavy metal. It is an important regulator of major cell signaling pathways in most mammalian cells, functions as an antioxidant and plays a role in maintaining genomic stability. Zinc deficiency leads to severe diseases in the brain, pancreas, liver, kidneys and reproductive organs. Zinc loss occurs during tumor development in a variety of cancers. The prostate normally contains abundant intracellular zinc and zinc loss is a hallmark of the development of prostate cancer development. The underlying mechanism of this loss is not clearly understood. The knowledge that excess zinc prevents the growth of prostate cancers suggests that zinc-mediated therapeutics could be an effective approach for cancer prevention and treatment, although challenges remain. This review summarizes the specific roles of zinc in several cancer types focusing on prostate cancer. The relationship between prostate cancer and the dysregulation of zinc homeostasis is examined in detail in an effort to understand the role of zinc in prostate cancer.

Zinc transporters maintain longevity by influencing insulin/IGF-1 activity in Caenorhabditis elegans

Adequate dietary intake of essential metals such as zinc is important for maintaining homeostasis. Abnormal zinc intake in Caenorhabditis elegans has been shown to increase or decrease normal lifespan by influencing the insulin/IGF-1 pathway. Distribution of zinc is achieved by a family of highly conserved zinc transport proteins (ZIPT in C. elegans). This study investigated the role of the zipt family of genes and showed that depletion of individual zipt genes results in a decreased lifespan. Moreover, zipt-16 and zipt-17 mutants synthetically interact with the insulin/IGF cofactors daf-16 and skn-1, and cause abnormal localisation of DAF-16. This study suggests that the zipt family of genes are required for maintaining normal lifespan through influencing the insulin/IGF-1 pathway.

Mitochondria-Targeting Antioxidant Provides Cardioprotection through Regulation of Cytosolic and Mitochondrial Zn2+ Levels with Re-Distribution of Zn2+-Transporters in Aged Rat Cardiomyocytes

Aging is an important risk factor for cardiac dysfunction. Heart during aging exhibits a depressed mechanical activity, at least, through mitochondria-originated increases in ROS. Previously, we also have shown a close relationship between increased ROS and cellular intracellular free Zn²⁺ ([Zn²⁺]_i) in cardiomyocytes under pathological conditions as well as the contribution of some re-expressed levels of Zn²⁺-transporters for redistribution of [Zn²⁺]_i among suborganelles. Therefore, we first examined the cellular (total) [Zn²⁺] and then determined the protein expression levels of Zn²⁺-transporters in freshly isolated ventricular cardiomyocytes from 24-month rat heart compared to those of 6-month rats. The [Zn²⁺]_i in the aged-cardiomyocytes was increased, at most, due to increased ZIP7 and ZnT8 with decreased levels of ZIP8 and ZnT7. To examine redistribution of the cellular [Zn²⁺]_i among suborganelles, such as Sarco/endoplasmic reticulum, S(E)R, and mitochondria ([Zn²⁺]_SER and [Zn²⁺]_Mit), a cell model (with galactose) to mimic the aged-cell in rat ventricular cell line H9c2 was used and demonstrated that there were significant increases in [Zn²⁺]_Mit with decreases in [Zn²⁺]_SER. In addition, the re-distribution of these Zn²⁺-transporters were markedly changed in mitochondria (increases in ZnT7 and ZnT8 with no changes in ZIP7 and ZIP8) and S(E)R (increase in ZIP7 and decrease in ZnT7 with no changes in both ZIP8 and ZnT8) both of them isolated from freshly isolated ventricular cardiomyocytes from aged-rats. Furthermore, we demonstrated that cellular levels of ROS, both total and mitochondrial lysine acetylation (K-Acetylation), and protein-thiol oxidation were significantly high in aged-cardiomyocytes from 24-month old rats. Using a mitochondrial-targeting antioxidant, MitoTEMPO (1 µM, 5-h incubation), we provided an important data associated with the role of mitochondrial-ROS production in the [Zn²⁺]_i-dyshomeostasis of the ventricular cardiomyocytes from 24-month old rats. Overall, our present data, for the first time, demonstrated that a direct mitochondria-targeting antioxidant treatment can be a new therapeutic strategy during aging in the heart through a well-controlled [Zn²⁺] distribution among cytosol and suborganelles with altered expression levels of the Zn²⁺-transporters.

A Brief Overview from the Physiological and Detrimental Roles of Zinc Homeostasis via Zinc Transporters in the Heart

Zinc (mostly as free/labile Zn²⁺) is an essential structural constituent of many proteins, including enzymes in cellular signaling pathways via functioning as an important signaling molecule in mammalian cells. In cardiomyocytes at resting condition, intracellular labile Zn²⁺ concentration ([Zn²⁺]_i) is in the nanomolar range, whereas it can increase dramatically under pathological conditions, including hyperglycemia, but the mechanisms that affect its subcellular redistribution is not clear. Therefore, overall, very little is known about the precise mechanisms controlling the intracellular distribution of labile Zn²⁺, particularly via Zn²⁺ transporters during cardiac function under both physiological and pathophysiological conditions. Literature data demonstrated that [Zn²⁺]_i homeostasis in mammalian cells is primarily coordinated by Zn²⁺ transporters classified as ZnTs (SLC30A) and ZIPs (SLC39A). To identify the molecular mechanisms of diverse functions of labile Zn²⁺ in the heart, the recent studies focused on the discovery of subcellular localization of these Zn²⁺ transporters in parallel to the discovery of novel physiological functions of [Zn²⁺]_i in cardiomyocytes. The present review summarizes the current understanding of the role of [Zn²⁺]_i changes in cardiomyocytes under pathological conditions, and under high [Zn²⁺]_i and how Zn²⁺ transporters are important for its subcellular redistribution. The emerging importance and the promise of some Zn²⁺ transporters for targeted cardiac therapy against pathological stimuli are also provided. Taken together, the review clearly outlines cellular control of cytosolic Zn²⁺ signaling by Zn²⁺ transporters, the role of Zn²⁺ transporters in heart function under hyperglycemia, the role of Zn²⁺ under increased oxidative stress and ER stress, and their roles in cancer are discussed.

Red Blood Cell and Serum Magnesium Levels Among Children and Adolescents With Sickle Cell Anemia

Patients with sickle cell anemia (SCA) can acquire many biochemical abnormalities, including altered magnesium levels. However, the roles of magnesium in the pathogenesis and management of SCA need to be determined. The aim of this work was to evaluate magnesium levels among pediatric patients with SCA in Basra, Iraq. The study employed a case-control design and examined 87 patients with SCA (3-15 years old) who had attended the Basra Center for Hereditary Blood Diseases while in a steady state and 90 apparently healthy control subjects. Complete blood count, red blood cell (RBC), and serum magnesium, calcium, potassium, sodium, zinc, and copper levels were measured in all subjects. The results revealed significantly lower RBC and serum magnesium levels among the patients with SCA (3.62 ± 0.42 and 1.35 ± 0.19 mg/dL, respectively) than those among the control subjects (4.47 ± 0.55 and 1.87 ± 0.27 mg/dL, respectively). In addition, compared to the control subjects, the patients with SCA had significantly lower serum levels of potassium, sodium, and zinc; significantly higher serum levels of copper; and significantly higher Ca/Mg and Na/Mg ratios. Among the SCA patients, the RBC magnesium level was significantly negatively associated with the frequencies of vaso-occlusive crises (r = - 0.423, P < 0.001) and disease-related hospitalization (r = - 0.225, P < 0.05). To conclude, the RBC magnesium level, but not the serum magnesium level, is significantly associated with vaso-occlusive crises and hospitalization. Therefore, screening and management of low RBC magnesium levels in SCA patients are required.

An Argument for Vitamin D, A, and Zinc Monitoring in Cirrhosis

Malnutrition is prevalent in cirrhosis. Vitamin and mineral deficiencies, including vitamin D, vitamin A, and zinc, are common and have been shown to correlate with survival. Our aim was to review the mechanisms of vitamin D, vitamin A, and zinc deficiencies in cirrhosis and the clinical assessment of affected patients, their outcomes based on the current literature, and management. This is a narrative review including the relevant literature for cirrhosis and vitamin D, vitamin A, and zinc deficiencies. Vitamin D deficiency has important effects in cirrhosis, regardless of the cause of chronic liver disease.These effects include associations with fibrosis and outcomes such as infections, hepatocellular carcinoma, and mortality. Vitamin A deficiency is associated with liver disease progression to cirrhosis and clinical decompensation, including occurrence of ascites or hepatic encephalopathy. Zinc deficiency can lead to hepatic encephalopathy and impaired immune function. Such deficiencies correlate with patient survival and disease severity. Caution should be applied when replacing vitamin D, vitamin A, and zinc to avoid toxicity. Identification and appropriate treatment of vitamin and mineral deficiencies in cirrhosis may reduce specific nutritional and cirrhosis-related adverse events. Routine monitoring of vitamin A, vitamin D and zinc levels in cirrhosis should be considered.

Zinc deficiency drives Th17 polarization and promotes loss of Treg cell function

A high number of illnesses and disorders are connected to zinc deficiency. Equally, T cell polarization and a balance between different T helper (Th) cell subsets are essential. Therefore, in this study, the influence of zinc deficiency on T cell polarization and on respective signaling pathways was investigated. We uncovered a significantly increased number of regulatory T cells (Treg) and Th17 cells in expanded T cells during zinc deficiency after 3 days of combined treatment with IL-2 and TGF-β1 (Treg) or IL-6 and TGF-β1 (Th17). No difference in Th1 and Th2 cell polarization between zinc-deficient and zinc-adequate status was prominent. On the molecular level, Smad signaling was significantly enhanced by stimulation with TGF-β1/IL-6 during zinc deficiency compared to adequate zinc condition. This represents an explanation for the elevated Th17 cell numbers associated with autoimmune disease especially during zinc deficiency. Moreover, Treg cell numbers are increased during zinc deficiency as well. However, those cells might be nonfunctional since a lower expression of miR-146a was uncovered compared to normal zinc concentrations. In summary, an adequate zinc homeostasis is fundamental to slow down or probably stop the progression of autoimmune diseases and infections. Therefore, supplementing zinc might be a therapeutic approach to dampen autoimmune diseases connected to Th17 cells.

The effects of zinc supplementation on primary human retinal pigment epithelium

Population-based and interventional studies have shown that elevated zinc levels can reduce the progression to advanced age-related macular degeneration. The objective of this study was to assess whether elevated extracellular zinc has a direct effect on retinal pigment epithelial cells (RPE), by examining the phenotype and molecular characteristics of increased extracellular zinc on human primary RPE cells. Monolayers of human foetal primary RPE cells were grown on culture inserts and maintained in medium supplemented with increasing total concentrations of zinc (0, 75, 100, 125 and 150 μM) for up to 4 weeks. Changes in cell viability and differentiation as well as expression and secretion of proteins were investigated. RPE cells developed a confluent monolayer with cobblestone morphology and transepithelial resistance (TER) >200 Ω*cm² within 4 weeks. There was a zinc concentration-dependent increase in TER and pigmentation, with the largest effects being achieved by the addition of 125 μM zinc to the culture medium, corresponding to 3.4 nM available (free) zinc levels. The cells responded to addition of zinc by significantly increasing the expression of Retinoid Isomerohydrolase (RPE65) gene; cell pigmentation; Premelanosome Protein (PMEL17) immunoreactivity; and secretion of proteins including Apolipoprotein E (APOE), Complement Factor H (CFH), and High-Temperature Requirement A Serine Peptidase 1 (HTRA1) without an effect on cell viability. This study shows that elevated extracellular zinc levels have a significant and direct effect on differentiation and function of the RPE cells in culture, which may explain, at least in part, the positive effects seen in clinical settings. The results also highlight that determining and controlling of available, as opposed to total added, zinc will be essential to be able to compare results obtained in different laboratories.

Zinc and linoleic acid pre-treatment attenuates biochemical and histological changes in the midbrain of rats with rotenone-induced Parkinsonism

BACKGROUND

Studies have suggested the supplementation of Zinc and Linoleic acid in the management of neurodegenerative disorders but none has investigated the combined effects. Little is known about the neuroprotective effects of either Zinc or Linoleic acid or their combination against development of Parkinsonism. This study was designed to investigate the neuroprotective effects of Zinc and Linoleic acid in rotenone-induced Parkinsonism in rats.

METHODS

Thirty-six young adult female rats weighing 100-150 g divided into six groups were used. Rats were induced with Parkinsonism by subcutaneous administration of rotenone (2.5 mg/kg) once a day for seven consecutive days. The rats received dimethyl sulfoxide (DMSO)/Olive oil or rotenone dissolved in DMSO/Olive oil. Groups III and IV received Zinc (30 mg/kg) or Linoleic acid (150 µl/kg) while group V received a combination of both, 2 weeks prior to rotenone injection. Groups II and VI served as negative (rotenone group) and positive (Levodopa groups) controls respectively. Oxidative stress levels were assessed by estimating Lipid peroxidation (MDA), total antioxidant capacity, Superoxide dismutase, reduced Glutathione (GSH), glutathione peroxidase and catalase in the midbrain. Histological examination was done to assess structural changes in the midbrain.

RESULTS

There was a significant prevention in lipid peroxidation and decrease in the antioxidant status in intervention-treated groups as compared to the rotenone treated group. In addition, histological examination revealed that Parkinsonian rat brains exhibited neuronal damage. Cell death and reduction in neuron size induced by rotenone was prevented by treatment with zinc, linoleic acid and their combination.

CONCLUSION

These results suggest that zinc and linoleic acid and their combination showed significant neuroprotective activity most likely due to the antioxidant effect.

Structural and functional analysis of the DOT1L-AF10 complex reveals mechanistic insights into MLL-AF10-associated leukemogenesis

The mixed-lineage leukemia (MLL)-AF10 fusion oncoprotein recruits DOT1L to the homeobox A (HOXA) gene cluster through its octapeptide motif leucine zipper (OM-LZ), thereby inducing and maintaining the MLL-AF10-associated leukemogenesis. However, the recognition mechanism between DOT1L and MLL-AF10 is unclear. Here, we present the crystal structures of both apo AF10^OM-LZ and its complex with the coiled-coil domain of DOT1L. Disruption of the DOT1L-AF10 interface abrogates MLL-AF10-associated leukemic transformation. We further show that zinc stabilizes the DOT1L-AF10 complex and may be involved in the regulation of the HOXA gene expression. Our studies may also pave the way for the rational design of therapeutic drugs against MLL-rearranged leukemia.

Increased free Zn2+ correlates induction of sarco(endo)plasmic reticulum stress via altered expression levels of Zn2+ -transporters in heart failure

Zn²⁺ -homoeostasis including free Zn²⁺ ([Zn²⁺ ]_i ) is regulated through Zn²⁺ -transporters and their comprehensive understanding may be important due to their contributions to cardiac dysfunction. Herein, we aimed to examine a possible role of Zn²⁺ -transporters in the development of heart failure (HF) via induction of ER stress. We first showed localizations of ZIP8, ZIP14 and ZnT8 to both sarcolemma and S(E)R in ventricular cardiomyocytes (H9c2 cells) using confocal together with calculated Pearson's coefficients. The expressions of ZIP14 and ZnT8 were significantly increased with decreased ZIP8 level in HF. Moreover, [Zn²⁺ ]_i was significantly high in doxorubicin-treated H9c2 cells compared to their controls. We found elevated levels of ER stress markers, GRP78 and CHOP/Gadd153, confirming the existence of ER stress. Furthermore, we measured markedly increased total PKC and PKCα expression and PKCα-phosphorylation in HF. A PKC inhibition induced significant decrease in expressions of these ER stress markers compared to controls. Interestingly, direct increase in [Zn²⁺ ]_i using zinc-ionophore induced significant increase in these markers. On the other hand, when we induced ER stress directly with tunicamycin, we could not observe any effect on expression levels of these Zn²⁺ transporters. Additionally, increased [Zn²⁺ ]_i could induce marked activation of PKCα. Moreover, we observed marked decrease in [Zn²⁺ ]_i under PKC inhibition in H9c2 cells. Overall, our present data suggest possible role of Zn²⁺ transporters on an intersection pathway with increased [Zn²⁺ ]_i and PKCα activation and induction of HF, most probably via development of ER stress. Therefore, our present data provide novel information how a well-controlled [Zn²⁺ ]_i via Zn²⁺ transporters and PKCα can be important therapeutic approach in prevention/treatment of HF.

MicroRNA dysregulation and esophageal cancer development depend on the extent of zinc dietary deficiency

Zinc deficiency (ZD) increases the risk of esophageal squamous cell carcinoma (ESCC), and marginal ZD is prevalent in humans. In rats, marked-ZD (3 mg Zn/kg diet) induces a proliferative esophagus with a 5-microRNA signature (miR-31, -223, -21, -146b, -146a) and promotes ESCC. Here we report that moderate and mild-ZD (6 and 12 mg Zn/kg diet) also induced esophageal hyperplasia, albeit less pronounced than induced by marked-ZD, with a 2-microRNA signature (miR-31, -146a). On exposure to an environmental carcinogen, ∼16% of moderate/mild-ZD rats developed ESCC, a cancer incidence significantly greater than for Zn-sufficient rats (0%) (P ≤ 0.05), but lower than marked-ZD rats (68%) (P < 0.001). Importantly, the high ESCC, marked-ZD esophagus had a 15-microRNA signature, resembling the human ESCC miRNAome, with miR-223, miR-21, and miR-31 as the top-up-regulated species. This signature discriminated it from the low ESCC, moderate/mild-ZD esophagus, with a 2-microRNA signature (miR-31, miR-223). Additionally, Fbxw7, Pdcd4, and Stk40 (tumor-suppressor targets of miR-223, -21, and -31) were downregulated in marked-ZD cohort. Bioinformatics analysis predicted functional relationships of the 3 tumor-suppressors with other cancer-related genes. Thus, microRNA dysregulation and ESCC progression depend on the extent of dietary Zn deficiency. Our findings suggest that even moderate ZD may promote esophageal cancer and dietary Zn has preventive properties against ESCC. Additionally, the deficiency-associated miR-223, miR-21, and miR-31 may be useful therapeutic targets in ESCC.

Impact of Labile Zinc on Heart Function: From Physiology to Pathophysiology

Zinc plays an important role in biological systems as bound and histochemically reactive labile Zn²⁺. Although Zn²⁺ concentration is in the nM range in cardiomyocytes at rest and increases dramatically under stimulation, very little is known about precise mechanisms controlling the intracellular distribution of Zn²⁺ and its variations during cardiac function. Recent studies are focused on molecular and cellular aspects of labile Zn²⁺ and its homeostasis in mammalian cells and growing evidence clarified the molecular mechanisms underlying Zn²⁺-diverse functions in the heart, leading to the discovery of novel physiological functions of labile Zn²⁺ in parallel to the discovery of subcellular localization of Zn²⁺-transporters in cardiomyocytes. Additionally, important experimental data suggest a central role of intracellular labile Zn²⁺ in excitation-contraction coupling in cardiomyocytes by shaping Ca²⁺ dynamics. Cellular labile Zn²⁺ is tightly regulated against its adverse effects through either Zn²⁺-transporters, Zn²⁺-binding molecules or Zn²⁺-sensors, and, therefore plays a critical role in cellular signaling pathways. The present review summarizes the current understanding of the physiological role of cellular labile Zn²⁺ distribution in cardiomyocytes and how a remodeling of cellular Zn²⁺-homeostasis can be important in proper cell function with Zn²⁺-transporters under hyperglycemia. We also emphasize the recent investigations on Zn²⁺-transporter functions from the standpoint of human heart health to diseases together with their clinical interest as target proteins in the heart under pathological condition, such as diabetes.

Evidence of Zinc in Affording Protection Against X-Ray-Induced Brain Injury in Rats

In the present world, X-rays have been regarded as one of the most efficient tools in medicine, industry and research. On the contrary, extensive human exposure to these rays is responsible for causing detrimental effects on physiological system. The aim of the present study was to investigate the role of zinc (Zn), if any, in mitigating the adverse effects induced by fractionated X-irradiation on rat brain. Female Sprague-Dawley rats weighing 170-200 g were divided into four different groups viz.: (a) normal control, (b) X-irradiated (21Gy), (c) zinc treated (227 mg/L in drinking water) and (d) X-irradiated + zinc treated. The skulls of animals belonging to groups (b) and (d) were exposed to X-rays in 30 fractions. Each fraction delivered a radiation dose of 70 rads, and rats were exposed to two fractions every day for 15 days, consecutively. X-ray treatment resulted in significant alterations in the neurobehavior, neurotransmitter levels and neuro-histoarchitecture of rats, whereas zinc co-treatment with X-rays resulted in significant improvement in these parameters. X-ray exposure also caused a significant increase in the levels of lipid peroxidation as well as activities of catalase and superoxide dismutase, which however were decreased upon simultaneous Zn treatment. On the contrary, X-ray treatment down-regulated the glutathione system, which were found to be up-regulated by zinc co-treatment. Further, protein expressions of p53 and NF-ҚB were found to be significantly elevated after X-irradiation, which were reversed following Zn supplementation. Hence, Zn seems to be an effective agent in mitigating the detrimental effects caused by exposure to X-rays.

Integration of metabolomics, transcriptomics, and microRNA expression profiling reveals a miR-143-HK2-glucose network underlying zinc-deficiency-associated esophageal neoplasia

Esophageal squamous cell carcinoma (ESCC) in humans is a deadly disease associated with dietary zinc (Zn)-deficiency. In the rat esophagus, Zn-deficiency induces cell proliferation, alters mRNA and microRNA gene expression, and promotes ESCC. We investigated whether Zn-deficiency alters cell metabolism by evaluating metabolomic profiles of esophageal epithelia from Zn-deficient and replenished rats vs sufficient rats, using untargeted gas chromatography time-of-flight mass spectrometry (n = 8/group). The Zn-deficient proliferative esophagus exhibits a distinct metabolic profile with glucose down 153-fold and lactic acid up 1.7-fold (P < 0.0001), indicating aerobic glycolysis (the “Warburg effect”), a hallmark of cancer cells. Zn-replenishment rapidly increases glucose content, restores deregulated metabolites to control levels, and reverses the hyperplastic phenotype. Integration of metabolomics and our reported transcriptomic data for this tissue unveils a link between glucose down-regulation and overexpression of HK2, an enzyme that catalyzes the first step of glycolysis and is overexpressed in cancer cells. Searching our published microRNA profile, we find that the tumor-suppressor miR-143, a negative regulator of HK2, is down-regulated in Zn-deficient esophagus. Using in situ hybridization and immunohistochemical analysis, the inverse correlation between miR-143 down-regulation and HK2 overexpression is documented in hyperplastic Zn-deficient esophagus, archived ESCC-bearing Zn-deficient esophagus, and human ESCC tissues. Thus, to sustain uncontrolled cell proliferation, Zn-deficiency reprograms glucose metabolism by modulating expression of miR-143 and its target HK2. Our work provides new insight into critical roles of Zn in ESCC development and prevention.

Comparison of distribution and toxicity of different types of zinc-based nanoparticles

Zinc-based nanoparticles (Zn-NPs), mainly zinc oxide (ZnO) NPs, have promising application in a wide area, but their potential harmful effects on environment and human health have been continuously raised together with their high dissolution rate. In this study, we coated the surface of ZnO NPs with phosphate (ZnP NPs) and sulfide (ZnS NPs) which have very low solubility in water, administered orally (0.5 and 1 mg/kg) to mice for 28 days, and then compared their biodistribution and toxicity. As expected, ZnO NPs were rapidly ionized in an artificial gastric fluid. On the other hand, ZnO NPs were more particlized in an artificial intestinal fluid than ZnP and ZnS NPs. After repeated dosing, all three types of Zn-NPs the most distributed in the spleen and thymus and altered the level of redox reaction-related metal ions in the tissues. We also found that three types of Zn-NPs clearly disturb tissue ion homeostasis and influence immune regulation function. However, there were no remarkable difference in distribution and toxicity following repeated exposure of three types of Zn-NPs, although Na+ and K+ level in the spleen and thymus were notably higher in mice exposed to ZnO NPs compared to ZnP and ZnS NPs. Taken together, we suggest that all three types of Zn-NPs may influence human health by disrupting homeostasis of trace elements and ions in the tissues. In addition, the surface transformation of ZnO NPs with phosphate and sulfide may not attenuate toxicity due to the higher particlization rate of ZnO NPs in the intestine, at least in part. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1363-1374, 2017.

Zinc deficiency and low enterocyte zinc transporter expression in human patients with autism related mutations in SHANK3

Phelan McDermid Syndrome (PMDS) is a genetic disorder characterized by features of Autism spectrum disorders. Similar to reports of Zn deficiency in autistic children, we have previously reported high incidence of Zn deficiency in PMDS. However, the underlying mechanisms are currently not well understood. Here, using inductively coupled plasma mass-spectrometry to measure the concentration of Zinc (Zn) and Copper (Cu) in hair samples from individuals with PMDS with 22q13.3 deletion including SHANK3 (SH3 and multiple ankyrin repeat domains 3), we report a high rate of abnormally low Zn/Cu ratios. To investigate possible underlying mechanisms, we generated enterocytes from PMDS patient-derived induced pluripotent stem cells and used Caco-2 cells with knockdown of SHANK3. We detected decreased expression of Zn uptake transporters ZIP2 and ZIP4 on mRNA and protein level correlating with SHANK3 expression levels, and found reduced levels of ZIP4 protein co-localizing with SHANK3 at the plasma membrane. We demonstrated that especially ZIP4 exists in a complex with SHANK3. Furthermore, we performed immunohistochemistry on gut sections from Shank3αβ knockout mice and confirmed a link between enterocytic SHANK3, ZIP2 and ZIP4. We conclude that apart from its well-known role in the CNS, SHANK3 might play a specific role in the GI tract.