Clinical, immunological, anti-inflammatory and antioxidant roles of zinc

Recent Advances in Targeting Transition Metals (Copper, Iron, and Zinc) in Alzheimer's Disease

Changes in the transition metal homeostasis in the brain are closely linked with Alzheimer's disease (AD), including intraneuronal iron accumulation and extracellular copper and zinc pooling in the amyloid plague. The brain copper, zinc, and iron surplus are commonly acknowledged characteristics of AD, despite disagreements among some. This has led to the theory that oxidative stress resulting from abnormal homeostasis of these transition metals may be a causative explanation behind AD. In the nervous system, the interaction of metals with proteins appears to be an essential variable in the development or suppression of neurodegeneration. Chelation treatment may be an option for treating neurodegeneration induced by transition metal ion dyshomeostasis. Some clinicians even recommend using chelating agents as an adjunct therapy for AD. The current review also looks at the therapeutic strategies that have been attempted, primarily with metal-chelating drugs. Metal buildup in the nervous system, as reported in the AD, could be the result of compensatory mechanisms designed to improve metal availability for physiological functions.

Zinc and Inflammatory Bowel Disease: From Clinical Study to Animal Experiment

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract (GI) with a high incidence rate globally, and IBD patients are often accompanied by zinc deficiency. This review aims to summarize the potential therapeutic value of zinc supplementation in IBD clinical patients and animal models. Zinc supplementation can relieve the severity of IBD especially in patients with zinc deficiency. The clinical severity of IBD were mainly evaluated through some scoring methods involving clinical performance, endoscopic observation, blood biochemistry, and pathologic biopsy. Through conducting animal experiments, it has been found that zinc plays an important role in alleviating clinical symptoms and improving pathological lesions. In both clinical observation and animal experiment of IBD, the therapeutic mechanisms of zinc interventions have been found to be related to immunomodulation, intestinal epithelial repair, and gut microbiota's balance. Furthermore, the antioxidant activity of zinc was clarified in animal experiment. Appropriate zinc supplementation is beneficial for IBD therapy, and the present evidence highlights that alleviating zinc-deficient status can effectively improve the severity of clinical symptoms in IBD patients and animal models.

Zinc, antioxidant enzymes in preeclampsia, and association with newborn outcome

BACKGROUND

The etiology of preeclampsia (PE) may be associated with the increased of production of reactive species and decreased antioxidant activity of enzymes. Inadequate intake of Zn can affect gestational health due to its biological functions, such as its role in the antioxidant defense system. The study aimed to assess the nutritional status of Zn and antioxidant enzymes in postpartum women and its correlation with neonatal outcomes.

METHODS

A cross-sectional analytical study was carried out at a referral gynecology and obstetrics hospital. A total of 119 women (PE = 58, HP = 61) participated in the study. A quantitative food-frequency questionnaire was used to assess food consumption and further analyze the dietary Zn levels. Zinc levels in plasma and erythrocytes samples were analyzed by flame atomic absorption spectrometry, catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) levels were determined by UV-Vis spectrophotometry.

RESULTS

Plasma and dietary intake Zn results were considered adequate and without statistical difference between groups. SOD levels were significantly higher in the HP group (p = 0.011), and CAT levels were higher in the PE group (p = 0.050). There was a positive correlation between SOD activity in women with PE and the weight of their newborns (r = 0.336, p=0.021).

CONCLUSION

The results showed adequate Zn levels (consumption and serum levels) in the groups studied, although with a reduction of plasma Zn in the PE group compared to the PH group. Zinc in plasma fractions and erythrocytes are important markers for oxidative stress, in particular, plasma Zn seems to be related to the rapid response to preeclampsia. The activity of antioxidant enzymes was elevated in the groups studied. Better SOD activity improves birth weight in children of pregnant women with preeclampsia.

Zinc Deficiency as a General Feature of Cancer: a Review of the Literature

Trace elements are minerals that are present in very low concentrations in the human body and yet are crucial for a wide range of physiological functions. Zinc, the second most abundant trace element, is obtained primarily from the diet. After being taken up in the intestine, zinc is distributed to various target organs, where it plays key roles in processes such as immunity, protein folding, apoptosis, and antioxidant activity. Given the important role of zinc in a wide range of enzymatic reactions and physiological processes, zinc deficiency has been identified in a variety of diseases, notably cancer. In recent years, multiple meta-analyses and reviews looking at zinc levels in individual cancer types have been published, as have a plethora of primary studies demonstrating a link between low zinc levels and specific types of cancer. In this review, we summarize recent evidence implicating low zinc concentrations in serum or tissues as a characteristic in a wide range of cancers. We also discuss preliminary findings indicating that zinc level measurement could ultimately become a useful clinical tool for cancer diagnosis and predicting outcomes in patients with cancer. Finally, we suggest future directions for further elucidating the role of zinc deficiency in cancer development and progression.

The nutritional roles of zinc for immune system and COVID-19 patients

Zinc (Zn) is a vital micronutrient that strengthens the immune system, aids cellular activities, and treats infectious diseases. A deficiency in Zn can lead to an imbalance in the immune system. This imbalance is particularly evident in severe deficiency cases, where there is a high susceptibility to various viral infections, including COVID-19 caused by SARS-CoV-2. This review article examines the nutritional roles of Zn in human health, the maintenance of Zn concentration, and Zn uptake. As Zn is an essential trace element that plays a critical role in the immune system and is necessary for immune cell function and cell signaling, the roles of Zn in the human immune system, immune cells, interleukins, and its role in SARS-CoV-2 infection are further discussed. In summary, this review paper encapsulates the nutritional role of Zn in the human immune system, with the hope of providing specific insights into Zn research.

Nutritional strategies to reduce intestinal cell apoptosis by alleviating oxidative stress

The gut barrier is the first line of defense against harmful substances and pathogens in the intestinal tract. The balance of proliferation and apoptosis of intestinal epithelial cells (IECs) is crucial for maintaining the integrity of the intestinal mucosa and its function. However, oxidative stress and inflammation can cause DNA damage and abnormal apoptosis of the IECs, leading to the disruption of the intestinal epithelial barrier. This, in turn, can directly or indirectly cause various acute and chronic intestinal diseases. In recent years, there has been a growing understanding of the vital role of dietary ingredients in gut health. Studies have shown that certain amino acids, fibers, vitamins, and polyphenols in the diet can protect IECs from excessive apoptosis caused by oxidative stress, and limit intestinal inflammation. This review aims to describe the molecular mechanism of apoptosis and its relationship with intestinal function, and to discuss the modulation of IECs' physiological function, the intestinal epithelial barrier, and gut health by various nutrients. The findings of this review may provide a theoretical basis for the use of nutritional interventions in clinical intestinal disease research and animal production, ultimately leading to improved human and animal intestinal health.

Association between the serum zinc level and nutritional status represented by the geriatric nutritional Rrisk index

BACKGROUND

Although it is widely known that patients with chronic kidney disease (CKD) can develop zinc deficiency, in our previous analysis, the estimated glomerular filtration rate (eGFR) was not independently associated with the serum zinc level. Thus, a post hoc analysis was conducted to investigate the involvement of nutritional status.

METHODS

A total of 655 subjects not on dialysis (402 males; mean age, 57 ± 18 years) who underwent serum zinc level measurements at Jikei University Hospital between April 2018 and March 2019 were selected using the Standardized Structured Medical Information eXchange2 (SS-MIX2) system. In addition, anthropometric data and the Geriatric Nutritional Risk Index (GNRI) representing nutritional status were obtained, and the relationship between the serum zinc level and nutritional status was investigated by multiple regression analysis.

RESULTS

The serum albumin level and the GNRI were lower in the zinc-deficiency group, and both were positively associated with the serum zinc level (rho = 0.44, P < 0.01 and rho = 0.44, P < 0.01, respectively). On multiple regression analysis, the GNRI (t = 3.09, P < 0.01) and serum albumin level (t = 4.75, P < 0.01) were independently associated with the serum zinc level. Although a higher eGFR was associated with a higher serum zinc level, this association disappeared on multivariate analysis.

CONCLUSION

In this post hoc analysis, the GNRI, as well as the serum albumin level, were correlated with the serum zinc level, indicating that nutritional status is an important determinant of the zinc level. Further investigations are needed to clarify the effects of nutritional status and kidney function on zinc deficiency.

Impact of micronutrients and nutraceuticals on cognitive function and performance in Alzheimer's disease

Alzheimer's disease (AD) is a major global health problem today and is the most common form of dementia. AD is characterized by the formation of β-amyloid (Aβ) plaques and neurofibrillary clusters, leading to decreased brain acetylcholine levels in the brain. Another mechanism underlying the pathogenesis of AD is the abnormal phosphorylation of tau protein that accumulates at the level of neurofibrillary aggregates, and the areas most affected by this pathological process are usually the cholinergic neurons in cortical, subcortical, and hippocampal areas. These effects result in decreased cognitive function, brain atrophy, and neuronal death. Malnutrition and weight loss are the most frequent manifestations of AD, and these are also associated with greater cognitive decline. Several studies have confirmed that a balanced low-calorie diet and proper nutritional intake may be considered important factors in counteracting or slowing the progression of AD, whereas a high-fat or hypercholesterolemic diet predisposes to an increased risk of developing AD. Especially, fruits, vegetables, antioxidants, vitamins, polyunsaturated fatty acids, and micronutrients supplementation exert positive effects on aging-related changes in the brain due to their antioxidant, anti-inflammatory, and radical scavenging properties. The purpose of this review is to summarize some possible nutritional factors that may contribute to the progression or prevention of AD, understand the role that nutrition plays in the formation of Aβ plaques typical of this neurodegenerative disease, to identify some potential therapeutic strategies that may involve some natural compounds, in delaying the progression of the disease.

Association Between Circulating Zinc and Risk for Childhood Asthma and Wheezing: A Meta-analysis on 21 Articles and 2205 Children

Asthma is one of the most frequent chronic diseases in children, and growing focus is placed on the exploration of attributable risk factors. Currently, no consensus has been reached on the implication of circulating zinc in the development of asthma. We aimed to conduct a meta-analysis to examine the association between circulating zinc and risk for childhood asthma and wheezing. We searched PubMed, Web of Science, EMBASE, and Google Scholar from inception until December 1, 2022. All procedures were performed independently and in duplicate. Random-effects model was adopted to derive standardized mean difference (SMD) and 95% confidence interval (95% CI). Statistical analyses were completed using the STATA software. Twenty-one articles and 2205 children were meta-analyzed. Overall, there was a statistically significant association between circulating zinc and risk for childhood asthma and wheezing (SMD: -0.38; 95% CI: -0.60 to -0.17; I2=82.6%, p<0.001), without evidence of publication bias as revealed by Begg's (p=0.608) and Egger (p=0.408) tests. Subgroup analyses showed that children with asthma or wheezing in Middle Eastern countries had significantly lower circulating zinc levels than controls (SMD: -0.42; 95% CI: -0.69 to -0.14; p<0.001; I2=87.1%). Additionally, average circulating zinc levels in asthma children were 0.41 μg/dl lower than that in controls, and the difference was statistically significant (SMD: -0.41; 95% CI: -0.65 to -0.16; p<0.001; I2=83.7%). By contrast, children with wheezing were 0.20 μg/dl lower than that in controls, and no between-group difference was noted (SMD=-0.20; 95% CI: -0.58 to 0.17; p=0.072; I2=69.1%). Our findings indicated that circulating zinc was associated with a significant risk for childhood asthma and its related symptom wheezing.

Zinc status and indicators of intestinal health in enterotoxigenic Escherichia coli F18 challenged newly weaned pigs fed diets with different levels of zinc

This study investigated the impact of an enterotoxigenic Escherichia coli (ETEC) F18 challenge on newly weaned pigs when fed one of three Zn levels (150, 1,400, or 2,500 ppm) on performance, Zn status, ETEC shedding, and diarrhea. The ETEC challenge was hypothesized to have a more pronounced negative impact on pigs fed a diet containing 150 ppm Zn compared to 1,400 or 2,500 ppm Zn for 14 d after weaning. The study included 72 ETEC F18 susceptible pigs weaned at ~28 d of age (d 0 of the study). The pigs were distributed according to initial weight and litter to one of the three dietary Zn levels. Half of the pigs were challenged with ETEC on d 1 and 2. The challenge reduced (P ≤ 0.03) feed intake and average daily gain (ADG) during d 3 to 5. Challenged pigs fed 150 ppm Zn had lower (P = 0.01) ADG during d 5 to 7 compared to those fed 1,400 or 2,500 ppm Zn, whereas control pigs' ADG were not affected by dietary Zn content. Challenged pigs fed 150 ppm Zn also showed lower (P < 0.01) fecal dry matter (DM) on d 5 compared to control pigs fed 150 ppm Zn and challenged pigs fed 1,400 or 2,500 ppm Zn. Challenge increased (P < 0.01) ETEC shedding in all groups, but challenged pigs fed 150 ppm Zn showed higher (P ≤ 0.05) fecal shedding of ETEC and toxins than when fed 1,400 or 2,500 ppm. On d 3, C-reactive protein concentration in plasma was lower (P < 0.03) for pigs fed 1,400 and 2,500 compared to 150 ppm Zn. Plasma haptoglobin and pig major acute phase protein were unaffected by dietary Zn content. On d 0, the serum Zn concentration was 586 ± 36.6 µg/L, which pigs fed 150 ppm Zn maintained throughout the study. The serum Zn concentration increased (P ≤ 0.07) in pigs fed 1,400 or 2,500 ppm Zn. The challenge decreased (P < 0.01) the serum Zn concentration in pigs fed 2,500 ppm Zn. On d 5 and 7, serum Zn concentration was similar for challenged pigs fed 1,400 and 2,500 ppm Zn, while control pigs fed 2,500 ppm Zn had higher (P < 0.01) serum Zn concentration than 1,400 ppm Zn. On d 7, serum Zn concentration tended (P = 0.08) to be lower for pigs with diarrhea (fecal DM ≤ 18%). In summary, these results indicate that newly weaned pigs fed 150 ppm Zn are more susceptible to ETEC F18 colonization and its adverse consequences such as diarrhea and reduced growth, even though challenge did not increase acute phase proteins.

Switching On/Off Amyloid Plaque Formation in Transgenic Animal Models of Alzheimer's Disease

A hallmark of Alzheimer's disease (AD) are the proteinaceous aggregates formed by the amyloid-beta peptide (Aβ) that is deposited inside the brain as amyloid plaques. The accumulation of aggregated Aβ may initiate or enhance pathologic processes in AD. According to the amyloid hypothesis, any agent that has the capability to inhibit Aβ aggregation and/or destroy amyloid plaques represents a potential disease-modifying drug. In 2023, a humanized IgG1 monoclonal antibody (lecanemab) against the Aβ-soluble protofibrils was approved by the US FDA for AD therapy, thus providing compelling support to the amyloid hypothesis. To acquire a deeper insight on the in vivo Aβ aggregation, various animal models, including aged herbivores and carnivores, non-human primates, transgenic rodents, fish and worms were widely exploited. This review is based on the recent data obtained using transgenic animal AD models and presents experimental verification of the critical role in Aβ aggregation seeding of the interactions between zinc ions, Aβ with the isomerized Asp7 (isoD7-Aβ) and the α4β2 nicotinic acetylcholine receptor.

The Impact of Antioxidants on Vitiligo and Melasma: A Scoping Review and Meta-Analysis

Reactive oxygen species (ROS) generated during melanogenesis make melanocytes particularly vulnerable to oxidative stress, influencing their survival and melanin synthesis. Oxidative stress, significantly present in vitiligo and recently also detected in melasma, triggers inflammatory cascades and melanogenesis, making antioxidants a promising therapeutic avenue. A systematic search was conducted on Embase and Pubmed to study the efficacy of antioxidants for treating vitiligo and/or melasma. Meta-analysis was performed to assess the difference in Melasma Severity Index (MASI) scores between baseline and follow-up. Various antioxidants like polypodium leucotomos, ginkgo biloba, catalase/superoxide dismutase, and vitamin E have potential in vitiligo. For melasma, vitamin C, silymarin, and niacinamide were among those showing promise in reducing pigmentation, with vitamin C displaying significant effects in meta-analysis. Different antioxidants improve both vitiligo and melasma, with an increased minimal erythema dose (MED) following UV exposure being significant for vitiligo and tyrosinase inhibition being crucial for melasma. However, the efficacy of individual antioxidants varies, and their exact mechanisms, especially in stimulating melanocyte proliferation and anti-inflammatory pathways, require further investigation to understand better and optimize their use.

Major depressive disorder as a neuro-immune disorder: Origin, mechanisms, and therapeutic opportunities

Notwithstanding advances in understanding the pathophysiology of major depressive disorder (MDD), no single mechanism can explain all facets of this disorder. An expanding body of evidence indicates a putative role for the inflammatory response. Several meta-analyses showed an increase in systemic peripheral inflammatory markers in individuals with MDD. Numerous conditions and circumstances in the modern world may promote chronic systemic inflammation through mechanisms, including alterations in the gut microbiota. Peripheral cytokines may reach the brain and contribute to neuroinflammation through cellular, humoral, and neural pathways. On the other hand, antidepressant drugs may decrease peripheral levels of inflammatory markers. Anti-inflammatory drugs and nutritional strategies that reduce inflammation also could improve depressive symptoms. The present study provides a critical review of recent advances in the role of inflammation in the pathophysiology of MDD. Furthermore, this review discusses the role of glial cells and the main drivers of changes associated with neuroinflammation. Finally, we highlight possible novel neurotherapeutic targets for MDD that could exert antidepressant effects by modulating inflammation.

Liposomal aggregates sustain the release of rapamycin and protect cartilage from friction

Liposomes show promise as biolubricants for damaged cartilage, but their small size results in low joint and cartilage retention. We developed a zinc ion-based liposomal drug delivery system for local osteoarthritis therapy, focusing on sustained release and tribological protection from phospholipid lubrication properties. Our strategy involved inducing aggregation of negatively charged liposomes with zinc ions to extend rapamycin (RAPA) release and improve cartilage lubrication. Liposomal aggregation occurred within 10 min and was irreversible, facilitating excess cation removal. The aggregates extended RAPA release beyond free liposomes and displayed irregular morphology influenced by RAPA. At nearly 100 µm, the aggregates were large enough to exceed the previously reported size threshold for increased joint retention. Tribological assessment on silicon surfaces and ex vivo porcine cartilage revealed the system's excellent protective ability against friction at both nano- and macro-scales. Moreover, RAPA was shown to attenuate the fibrotic response in human OA synovial fibroblasts. Our findings suggest the zinc ion-based liposomal drug delivery system has potential to enhance OA therapy through extended release and cartilage tribological protection, while also illustrating the impact of a hydrophobic drug like RAPA on liposome aggregation and morphology.

Effect of Organic Selenium on the Homeostasis of Trace Elements, Lipid Peroxidation, and mRNA Expression of Antioxidant Proteins in Mouse Organs

(1) In this study we determined the effect of long-term selenomethionine administration on the oxidative stress level and changes in antioxidant protein/enzyme activity; mRNA expression; and the levels of iron, zinc, and copper. (2) Experiments were performed on 4-6-week-old BALB/c mice, which were given selenomethionine (0.4 mg Se/kg b.w.) solution for 8 weeks. The element concentration was determined via inductively coupled plasma mass spectrometry. mRNA expression of SelenoP, Cat, and Sod1 was quantified using real-time quantitative reverse transcription. Malondialdehyde content and catalase activity were determined spectrophotometrically. (3) After long-term SeMet administration, the amount of Se increased by 12-fold in mouse blood, 15-fold in the liver, and 42-fold in the brain, as compared to that in the control. Exposure to SeMet decreased amounts of Fe and Cu in blood, but increased Fe and Zn levels in the liver and increased the levels of all examined elements in the brain. Se increased malondialdehyde content in the blood and brain but decreased it in liver. SeMet administration increased the mRNA expression of selenoprotein P, dismutase, and catalase, but decreased catalase activity in brain and liver. (4) Eight-week-long selenomethionine consumption elevated Se levels in the blood, liver, and especially in the brain and disturbed the homeostasis of Fe, Zn, and Cu. Moreover, Se induced lipid peroxidation in the blood and brain, but not in the liver. In response to SeMet exposure, significant up-regulation of the mRNA expression of catalase, superoxide dismutase 1, and selenoprotein P in the brain, and especially in the liver, was determined.

Effectiveness of non-pharmaceutical intervention on sperm quality: a systematic review and network meta-analysis

Infertility affects about 10% of the world's population and has been recognized by the WHO as a global public health problem. The aim of this network meta-analysis was to investigate the efficacy of non-pharmaceutical interventions on sperm quality. All randomized clinical trials (RCTs) from the PubMed, MEDLINE, Embase, China national knowledge infrastructure (CNKI), Wanfang database, and Cochrane Library databases evaluating the effectiveness of non-pharmaceutical interventions on semen parameters using network meta-analyses. Results of the ω-3 fatty acid, lycopene, acupuncture, and vitamin suggested evident advantages in improving sperm concentration (MD, 9.93 (95% CI, 7.21 to 12.65)), (MD, 8.79 (95% CI, 2.67 to 14.91)), (MD, 5.40 (95% CI, 2.32 to 8.49)) and (MD, 3.82 (95% CI, 0.70 to 6.94) respectively). Acupuncture has a significant advantage over placebo in improving sperm total motility (MD, 17.81 (95% CI, 10.32 to 25.29)), and the effect of lycopene was obviously greater than that of placebo (MD, 19.91 (95% CI, 2.99 to 36.83)). Lycopene, Coenzyme Q10 (CoQ10), acupuncture, ω-3 fatty acid, and vitamin suggested significant advantages in improving sperm forward motility (MD, 8.64 (95% CI, 1.15 to 16.13), MD, 5.28 (95% CI, 2.70 to 7.86), MD, 3.95 (95% CI, 3.23 to 4.67), MD, 3.50 (95% CI, 2.21 to 4.79)) and (MD, 2.38 (95% CI, 0.96 to 3.80) respectively). This review establishes that non-pharmaceutical interventions, particularly acupuncture, exercise, lycopene, ω-3 fatty acids, CoQ10, zinc, vitamins, selenium, carnitine, or foods rich in these supplements, profitably improve sperm quality that may be used to treat male infertility.

Nutrient Therapy for the Improvement of Fatigue Symptoms

Fatigue, characterised by lack of energy, mental exhaustion and poor muscle endurance which do not recover following a period of rest, is a common characteristic symptom of several conditions and negatively impacts the quality of life of those affected. Fatigue is often a symptom of concern for people suffering from conditions such as fibromyalgia, chronic fatigue syndrome, cancer, and multiple sclerosis. Vitamins and minerals, playing essential roles in a variety of basic metabolic pathways that support fundamental cellular functions, may be important in mitigating physical and mental fatigue. Several studies have examined the potential benefits of nutrients on fatigue in various populations. The current review aimed to gather the existing literature exploring different nutrients' effects on fatigue. From the searches of the literature conducted in PubMed, Ovid, Web of Science, and Google scholar, 60 articles met the inclusion criteria and were included in the review. Among the included studies, 50 showed significant beneficial effects (p < 0.05) of vitamin and mineral supplementation on fatigue. Altogether, the included studies investigated oral or parenteral administration of nutrients including Coenzyme Q10, L-carnitine, zinc, methionine, nicotinamide adenine dinucleotide (NAD), and vitamins C, D and B. In conclusion, the results of the literature review suggest that these nutrients have potentially significant benefits in reducing fatigue in healthy individuals as well as those with chronic illness, both when taken orally and parenterally. Further studies should explore these novel therapies, both as adjunctive treatments and as sole interventions.

Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review

INTRODUCTION

Exposure to blue light has seriously increased in our environment since the arrival of light emitting diodes (LEDs) and, in recent years, the proliferation of digital devices rich in blue light. This raises some questions about its potential deleterious effects on eye health. The aim of this narrative review is to provide an update on the ocular effects of blue light and to discuss the efficiency of methods of protection and prevention against potential blue light-induced ocular injury.

METHODS

The search of relevant English articles was conducted in PubMed, Medline, and Google Scholar databases until December 2022.

RESULTS

Blue light exposure provokes photochemical reactions in most eye tissues, in particular the cornea, the lens, and the retina. In vitro and in vivo studies have shown that certain exposures to blue light (depending on the wavelength or intensity) can cause temporary or permanent damage to some structures of the eye, especially the retina. However, currently, there is no evidence that screen use and LEDs in normal use are deleterious to the human retina. Regarding protection, there is currently no evidence of a beneficial effect of blue blocking lenses for the prevention of eye diseases, in particular age-related macular degeneration (AMD). In humans, macular pigments (composed of lutein and zeaxanthin) represent a natural protection by filtering blue light, and can be increased through increased intake from foods or food supplements. These nutrients are associated with lower risk for AMD and cataract. Antioxidants such as vitamins C, E, or zinc might also contribute to the prevention of photochemical ocular damage by preventing oxidative stress.

CONCLUSION

Currently, there is no evidence that LEDs in normal use at domestic intensity levels or in screen devices are retinotoxic to the human eye. However, the potential toxicity of long-term cumulative exposure and the dose-response effect are currently unknown.

Potentials of Dietary Zinc Supplementation in Improving Growth Performance, Health Status, and Meat Quality of Broiler Chickens

The demand for chicken meat is on the rise, necessitating high level of production and efficient feed conversion which to a certain extent can be actualized by the use of specific trace minerals like zinc (Zn). Zn is a part of several enzymes involved in the metabolism of protein, fat, carbohydrates, and nucleic acids. In addition, Zn has antioxidant properties and is vital for hormone function, including growth, pancreatic, and sex hormones. Its deficiency in animals is characterized by poor fertility, decreased feed intake, poor growth, testicular atrophy, and weakened immunity. Nano-Zn sources have been shown to be more bioavailable than conventional zinc (organic and inorganic) sources. Zn from organic sources, on the other hand, has higher bioavailability than Zn from inorganic sources. Furthermore, Zn supplementation promotes growth, enhances antioxidant capacity, modulates the immunity, and improves health indices in broiler chickens. Published studies have demonstrated that Zn supplementation has the potential to improve carcass yield and meat quality in broilers with various research contradictions. However, a clear understanding of the role of Zn in broiler nutrition is still lacking, necessitating further research. As a result, the purpose of this review was to highlight the influence of Zn (organic or inorganic) supplementation on growth, blood characteristics, antioxidant status, immune responses, Zn tissue/fecal concentrations, intestinal villus histomorphology, and meat quality of broiler chickens as well as Zn bioavailability to understand the role of Zn in broiler nutrition, resolve contradictory research results, and identify knowledge gaps. Understanding the role of dietary Zn in broiler chicken nutrition and meat quality will avail important suggestion on policy advancements and sustainable use of Zn in the broiler chicken industry.

Implication of apoptosis and oxidative stress in mitigation of ivermectin long-term hazards by zinc nanoparticles in male rabbits

Ivermectin is the medication of choice for treating human onchocerciasis and is used in veterinary medicine to treat a variety of ectoparasites and endoparasites. This study was designed to investigate the effects of zinc nanoparticles (ZnNPs) on the fertility of male rabbits exposed to experimental ivermectin (IVM) intoxication. A total of 72 mature male rabbits were equally divided into 4 groups (n = 18). The first group (CTR) served as control; the second group (IVM) received subcutaneous injection of IVM (0.2 mg/kg body weight); the third group (ZnNPs) fed on zinc nanoparticles (60 mg/kg diet); and the fourth group (ZnNPs + IVM) were administered IVM and zinc nanoparticles at the same doses. The experiment lasted for 9 weeks. Results revealed that IVM-intoxicated rabbits showed impaired growth performance parameters, including body weight, total body weight gain (TBWG), total feed intake (TFI), and feed conversion ratio (FCR). Moreover, carcass characteristic and fertility parameters (including semen quality parameters and testosterone levels) were also impaired after IVM administration. Additionally, testicular malondialdehyde (MDA) and antioxidant (reduced glutathione, superoxide dismutase, catalase) levels as well as the histopathology and immunohistochemical expression of caspase 3 and PCNA in the testes and epididymis were detrimentally affected. On the contrary, ZnNP administration efficiently improved most of these parameters in IVM-intoxicated rabbits. In conclusion, ZnNPs exhibited promising ability for improving the growth and fertility status of rabbits and reducing the deleterious effects of IVM possibly through the suppression of apoptotic and oxidative pathways.

Toward Smart Biomimetic Apatite-Based Bone Scaffolds with Spatially Controlled Ion Substitutions

Biomimetic apatites exhibit a high reactivity allowing ion substitutions to modulate their in vivo response. We developed a novel approach combining several bioactive ions in a spatially controlled way in view of subsequent releases to address the sequence of events occurring after implantation, including potential microorganisms' colonization. Innovative micron-sized core-shell particles were designed with an external shell enriched with an antibacterial ion and an internal core substituted with a pro-angiogenic or osteogenic ion. After developing the proof of concept, two ions were particularly considered, Ag⁺ in the outer shell and Cu²⁺ in the inner core. In vitro evaluations confirmed the cytocompatibility through Ag-/Cu-substituting and the antibacterial properties provided by Ag⁺. Then, these multifunctional "smart" particles were embedded in a polymeric matrix by freeze-casting to prepare 3D porous scaffolds for bone engineering. This approach envisions the development of a new generation of scaffolds with tailored sequential properties for optimal bone regeneration.

Dietary Zinc Is Associated with Cardiac Function in the Older Adult Population

The elderly is a group at particularly high cardiovascular risk. The coexistence of chronic diseases and use of multiple medications creates the need to look for non-pharmacological agents to improve cardiovascular health in that population. In view of reports on the potential role of zinc in enhancing pathways of myocardial tissue repair, the aim of this study was to evaluate the association between dietary zinc intake and cardiac structure and function in individuals of advanced age. The study group included 251 community-dwelling patients, with a median age of 80 years. Dieta 6.0 software was used for calculation of zinc consumption. Percentage of Recommended Dietary Allowance (RDA) for zinc correlated with left ventricular ejection fraction (LVEF) (r = 0.196, p < 0.05), left ventricular mass index (r = -0.137, p < 0.05) and tricuspid annular plane systolic excursion (TAPSE) (r = 0.153, p < 0.05), while zinc density did so with E/E' ratio (r = -0.127, p < 0.05). In a multiple stepwise regression analysis, the best determinants of LVEF were %RDA for zinc (p = 0.014; β = 0.143), presence of coronary artery disease (p < 0.001; β = -0.39) and age (p = 0.036; β = -0.12). Furthermore, %RDA for zinc (p = 0.009; β = 0.16), female sex (p = 0.005; β = -0.171), beta-blocker use (p = 0.024; β = -0.136), body mass index (p = 0.008; β = 0.16) and heart rate (p = 0.0006; β = -0.209) had an independent effect on TAPSE. In conclusion, in individuals of very advanced age, lower zinc intake is associated with poorer cardiac function. Therefore, increasing the recommended zinc intake in this group deserves consideration.

Role of Interaction between Zinc and Amyloid Beta in Pathogenesis of Alzheimer’s Disease

Progression of Alzheimer's disease is accompanied by the appearance of extracellular deposits in the brain tissues of patients with characteristic supramolecular morphology (amyloid plaques) the main components of which are β-amyloid isoforms (Aβ) and biometal ions (zinc, copper, iron). For nearly 40 years and up to the present time, the vast majority of experimental data indicate critical role of formation and accumulation of amyloid plaques (cerebral amyloidogenesis) in pathogenesis of Alzheimer's disease, however, nature of the molecular agents that initiate cerebral amyloidogenesis, as well as causes of aggregation of the native Aβ molecules in vivo remained unknown for a long time. This review discusses the current level of fundamental knowledge about the molecular mechanisms of interactions of zinc ions with a number of Aβ isoforms present in amyloid plaques of the patients with Alzheimer's disease, and also shows how this knowledge made it possible to identify driving forces of the cerebral amyloidogenesis in Alzheimer's disease and made it possible to determine fundamentally new biomarkers and drug targets as part of development of innovative strategy for diagnosis and treatment of Alzheimer's disease.

Nano Zinc Oxide Improves Performance, IGF-I mRNA Expression, Meat Quality, and Humeral Immune Response and Alleviates Oxidative Stress and NF-κB Immunohistochemistry of Broiler Chickens

A 35-day trial was set to explore the effects of different dietary zinc sources on growth, insulin-like growth factor I (IGF-I) mRNA expression, meat quality, immune response, antioxidant activity, and immunohistochemistry of nuclear factor kappa B (NF-κ7B) of broiler chickens. Ross 308 broiler chicks (n = 156) were randomly assigned into four experimental groups. The G1 received the basal control diet without zinc supplementation; the G2, G3, and G4 were supplemented with zinc oxide, zinc lysine, and nano zinc oxide, respectively, at a level of 40 mg Zn/kg diet. The data revealed that nano zinc oxide linearly improved the overall growth performance parameters. Nano zinc oxide linearly elevated (P < 0.001) mRNA expression of IGF-I followed by G3. The pH value of breast muscle in G4 shows a linearly decreasing value (P < 0.001). Also, the linearly highest expressible release volume percentage and lightness (L*) value with the lowest redness (a*) value (P < 0.05) were recorded in G4 and G3. A numerical increase in the total antibody titer was recorded on the 35^th day in the G3 and G4. A numerical elevation in the superoxide dismutase (SOD) and a numerical reduction in the serum malondialdehyde (MDA) were recorded in the G4. The section of the liver from G4 revealed significantly very low expression of NF-κB staining. It is concluded that nano zinc oxide is considered the more trending zinc source. It had no negative effects on the health status and can be used in broiler diet premix.

The Dietary Supplementation of Copper and Zinc Nanoparticles Improves Health Condition of Young Dairy Calves by Reducing the Incidence of Diarrhoea and Boosting Immune Function and Antioxidant Activity

This study was conducted to evaluate the effect of nano copper (nano Cu) and nano zinc (nano Zn) supplementation on the biomarkers of immunity and antioxidant and health status attributes in young dairy calves. Twenty-four young cattle calves were randomly assigned into four groups (6 calves per group) on a body weight and age basis for a period of 120 days. The feeding regimen was the same in all the groups except that these were supplemented with 0.0 mg nano Cu and nano Zn (control), 10 mg nano Cu (_nanoCu₁₀), 32 mg nano Zn (nanoZn₃₂), and a combination of nano Cu and nano Zn (_nanoCu₁₀ + _nanoZn₃₂) per kg dry matter (DM) basis in four respective groups. Supplementation of nano Cu along with nano Zn improves immune response which was evidenced from higher immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin A (IgA), total immunoglobulin (TIg), and Zn sulphate turbidity (ZST) units and lower plasma concentrations of tumour necrosis factor-α (TNF-α) and cortisol in the nanoCu10 + nanoZn32 group. There was no effect of treatment on the plasma concentrations of immunoglobulin E (IgE) and interferon-gamma (IFN-γ). Antioxidant status was also better in the nanoCu10 + nanoZn32 group as evidenced by lower concentrations of malondialdehyde (MDA) and higher activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), ceruloplasmin (Cp), and total antioxidant status (TAS). However, treatment did not exert any effect on catalase (CAT) activity. Although the nano Cu or nano Zn supplementation, either alone or in combination, did not exert any effect on growth performance or body condition score (BCS), the frequency of diarrhoea and incidence of diarrhoea were lower, while faecal consistency score (FCS) and attitude score were better in the _nanoCu₁₀ + _nanoZn₃₂ groups. In the control group, one calf was found affected with joint illness and two calves were found affected with navel illness. During the experimental period, none of the calves in all four groups were found to be affected by pneumonia. The findings of this study revealed that dietary supplementation of nano Cu in combination with nano Zn improved the health status of young dairy calves by improving immunity and antioxidant status.

Can iron, zinc, copper and selenium status be a prognostic determinant in COVID-19 patients?

In severe COVID-19, the levels of iron (Fe), copper (Cu), zinc (Zn) and selenium (Se), do not only regulate host immune responses, but modify the viral genome, as well. While low serum Fe concentration is an independent risk factor for the increased death rate, Zn controls oxidative stress, synthesis of inflammatory cytokines and viral replication. Therefore, Zn deficiency associates with a worse prognosis. Although Cu exposure inactivates the viral genome and exhibits spike protein dispersal, increase in Cu/Zn due to high serum Cu levels, are correlated with enhanced risk of infections. Se levels are significantly higher in surviving COVID-19 patients. Meanwhile, both Zn and Se suppress the replication of SARS-CoV-2. Since the balance between the deficiency and oversupply of these metals due to a reciprocal relationship, has decisive effect on the prognosis of the SARS-CoV-2 infection, monitoring their concentrations may facilitate improved outcomes for patients suffering from COVID-19.

Tissue Heavy Metals in Liver Diseases

BACKGROUND

Our objective was to determine the levels of heavy metals, oxidants, and antioxidants in liver tissue of patients with chronic liver disease (CLD) compared with healthy living liver donors (LLDs).

METHODS

We obtained liver specimens from patients undergoing liver transplant for CLD. Samples were also obtained from LLDs. Biochemical analyses were performed on all samples, and the levels of liver tissue, heavy metal, and oxidant-antioxidants biomarker levels in patients with CLD were compared with those measured in LLDs.

RESULTS

One hundred and eighteen individuals were included for analyses. Fifty-nine were patients with CLD, and 59 were LLDs. The median levels of liver tissue of superoxide dismutase (P = .009), glutathione peroxidase (P = .042), total oxidant status (P = .006), oxidative stress index (P < .001), and copper (P = .035) were prominently more elevated in CLD than LLDs. On the other hand, the median levels of liver tissue of cadmium (P < .001), selenium (P = .042), and zinc (P < .001) levels were more elevated in the LLDs than patients with CLD. The 2 groups were similar in terms of total antioxidant status, manganese, arsenic, and lead levels.

CONCLUSIONS

Superoxide accumulation in the liver was higher in patients with CLD. Concerning heavy metals, only the median tissue copper was elevated in patients with CLD with higher Cu/Zn ratio. Cadmium, selenium, and zinc were significantly higher in the healthy LLDs.

Influence of zinc levels and Nrf2 expression in the clinical and pathological changes in patients with diabetic nephropathy

Objective

We investigated the correlation between zinc levels and Nrf2 expression and potential effects on the clinicopathology of patients with diabetic nephropathy (DN).

Methods

We selected 30 patients with DN, diagnosed via renal biopsy at our hospital from March 2018 to November 2019, and enrolled 30 healthy individuals from a medical examination center as the control group. Patients with DN were divided into normal-zinc and low-zinc groups. We detected the levels of zinc, copper, and Nrf2 mRNA in their serum, and collected the clinical and pathological data of DN patients.

Results

Serum zinc level and Nrf2 mRNA expression were significantly decreased in patients with DN compared to those of healthy people (P < 0.05). Of the 30 patients, 16 had low zinc (53.3%) and 14 had normal zinc levels (46.7%). There was no significant difference in the blood Nrf2 mRNA expression between the two groups (P > 0.05). However, the expression of Nrf2 in the kidney tissue of the low-zinc group was significantly lower compared to the normal-zinc group (P < 0.05). Diastolic blood pressure and copper levels were significantly higher in the low-zinc group (P < 0.05). In contrast, body mass index, red blood cell count, Hb level, and the ratio of zinc to copper were significantly lower in the low-zinc group (P < 0.05). The pathological classifications of the low-zinc group were more severe (P < 0.05).

Conclusion

Patients with DN were more likely to have zinc deficiency and lower expression of Nrf2. Additionally, DN patients with zinc deficiency were prone to have more severe clinical and pathological manifestations.

The impact of zinc on the molecular signaling pathways in the diabetes disease

Since there's been an upsurge in people with diabetes or pre-diabetes conditions, many studies have been conducted to evaluate approaches for reducing the complications of diabetes. One of the most common therapeutic elements suggested for this purpose is zinc (Zn). Zn has long been shown to positively improve complications of both type 1 and type 2 diabetes. This review aims to provide comprehensive information about the influence of Zn on the various signaling pathways in multiple tissues with diabetic conditions, with great attention to the treatment period and effective dose of Zn.

Nutrient Deficiencies and Potential Alteration in Plasma Levels of Naturally Acquired Malaria-Specific Antibody Responses in Tanzanian Children

Immunoglobulin G (IgG) subclasses have been suggested to confer naturally acquired immunity to Plasmodium falciparum malaria. Cytophilic IgG1 and IgG3 with their potential for opsonization, phagocytosis, and antibody-dependent cellular inhibition in association with monocytes have been suggested to have a critical role in malaria. The potential for production of antibodies is influenced by micronutrient status. This study aimed at exploring the effect of micronutrients, particularly zinc status, on the profiles of IgG subclasses in 304 Tanzanian children aged ≤ 5 years. An enzyme-linked immunosorbent assay was performed using whole asexual blood stage malaria antigens to determine plasma malaria-specific antibody titers. This baseline cross-sectional study was done from 2005 – 2010 prior to the larger randomized control trial of the Micronutrient and Child Health (MACH) Study. Plasma concentrations of zinc and magnesium were measured by inductively coupled plasma atomic emission spectrometry and results correlated with plasma IgG subclass levels. The findings reveal zinc deficiency to possibly influence the production of IgM, total IgG, and several IgG subclasses in a malaria status-dependent manner. Among IgG subclasses, IgG3 and partly IgG2 displayed a remarkable association with zinc deficiency, particularly IgG3 which was predominant in children with malaria. Nevertheless, zinc, magnesium, and malaria status did not influence the association between IgG3 and IgG4. The study leads to the conclusion that, under conditions of micronutrient deficiency and malaria status, an imbalance in IgG subclass production may occur leading to predominantly higher levels of IgG3 and IgG2 that may not confer sufficient protection from infection. The profile of both cytophilic and non-cytophilic IgG subclasses has been shown to be variably influenced by zinc status; the effects vary with age at least in under-fives. These results provide insight for inclusion of micronutrients, particularly precise amounts of zinc, in future malaria interventional programs in endemic areas.

Associations between Meat and Vegetable Intake, Cooking Methods, and Asthenozoospermia: A Hospital-Based Case–Control Study in China

Background: The role of meat and vegetable intake in the development of asthenozoospermia has been controversial, and the role of cooking methods for meat and vegetables in the association has yet to be determined. The present study aimed to illuminate the relationship between the consumption and cooking methods of meat and vegetables and the risk of asthenozoospermia. Methods: In this hospital-based case–control study, we enrolled 552 patients with asthenozoospermia and 585 healthy controls. Dietary information was assessed using a validated self-administered food frequency questionnaire. Asthenozoospermia was diagnosed according to the fifth edition of the WHO laboratory manual for the examination and processing of human semen. Results: Participants in the highest tertile of total meat and unprocessed meat intake had a 44% and 39% lower risk of asthenozoospermia than those in the lowest tertile (OR = 0.56, 95% CI: 0.37, 0.87 and OR = 0.61, 95% CI: 0.40, 0.93), respectively. Participants with the highest processed meat consumption showed higher risk (OR = 1.44, 95% CI: 1.01, 2.06). Raw vegetable consumption was negatively associated with the risk of asthenozoospermia (OR = 0.67, 95% CI: 0.45, 0.98). The stir-frying cooking method for meat was associated with increased risk of asthenozoospermia (OR = 1.58, 95% CI: 1.02, 2.46). Conclusions: Intake of total meat, unprocessed meat, and raw vegetable may reduce asthenozoospermia risk, while higher consumption of processed meat may increase the risk. Cooking methods may play a role in these associations. These findings need to be confirmed in large and prospective cohort studies.

Zinc based metal organic framework with antibacterial and anti- inflammatory properties for promoting wound healing

The synergistic effect of antibacterial and anti-inflammatory is needed to overcome the problem of wound healing difficulties. Based on the favorable antibacterial and anti-inflammatory effect of zinc ions (Zn²⁺) and the physicochemical properties of metal organic frameworks (MOFs), we prepared nanosized zinc-based MOF: Zn-BTC with the ability to slowly release Zn²⁺. In cellular levels, Zn-BTC possessed lower toxicity to fibroblasts and enhanced capacity of cell proliferation and migration. It also had good bactericidal effect on multiple drug-resistant bacteria by reducing 41.4% MRSA and 47.2% Escherichia coli. In addition, Zn-BTC also displayed the ability of lowering the expression of antioxidant genes: superoxide dismutase 1, superoxide dismutase 2 and interleukin 6, and enhancing the expression of wound healing genes: transforming growth factors-β and type I collagen. Finally, it also demonstrated that Zn-BTC could effectively improve the skin wound healing of SD rats and had no toxicity on major organs. The favorable biocompatibility, antibacterial and anti-inflammatory properties of Zn-BTC gave a new insight of designing novel MOFs for promoting skin wound healing.

Feasibility evaluation of a Zn-Cu alloy for intrauterine devices: In vitro and in vivo studies

The comprehensively adopted copper-containing intrauterine devices (Cu-IUDs) present typical adverse effects such as bleeding and pain at the initial stage of post-implantation. The replacement of Cu material is demanded. Zinc and its alloys, the emerging biodegradable materials, exhibited contraceptive effects since 1969. In this work, we evaluated the feasibility of bulk Zn alloys as IUD active material. Using pure Cu and pure Zn as control groups, we investigated the contraceptive performance of Zn-0.5Cu and Zn-1Cu alloys via in vitro and in vivo tests. The results showed that the main corrosion product of Zn-Cu alloys is ZnO from both in vitro and in vivo studies. CaZn₂(PO₄)₂·2H₂O is formed atop after long-term immersion in simulated uterine fluid, whereas CaCO₃ is generally formed atop after implantation in the rat uterine environment. The cytocompatibility of the Zn-1Cu alloy was significantly higher than that of the pure Zn and pure Cu to the human endometrial epithelial cell lines. Furthermore, the in vivo results showed that the Zn-1Cu alloy presented much improved histocompatibility, least damage and the fastest recovery on endometrium structure in comparison to pure Zn, Zn-0.5Cu and pure Cu. The systematic and comparing studies suggest that Zn-1Cu alloy can be considered as a possible candidate for IUD with great biochemical and biocompatible properties as well as high contraceptive effectiveness. STATEMENT OF SIGNIFICANCE: The existing adverse effects with the intrinsic properties of copper materials for copper-containing intrauterine devices (Cu-IUD) are of concerns in their employment. Such as burst release of cupric ions (Cu²⁺) at the initial stage of the Cu-IUD. Zinc and its alloys which have been emerging as a potential biodegradable material exhibited contraceptive effects since 1969. In this study, Zn-1Cu alloys displayed significantly improved biocompatibility with human uterus cells and a decreased inflammatory response within the uterus. Therefore, high antifertility efficacy of the Zn-1Cu alloy was well maintained, while the adverse effects are significantly eased, suggesting that the Zn-1Cu alloy is promising for IUD.

COVID-19 pandemic: the delta variant, T-cell responses, and the efficacy of developing vaccines

Background

The mayhem COVID-19 that was ushered by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) was declared pandemic by the World Health Organization in March 2020. Since its initial outbreak in late 2019, the virus has affected hundreds of million adults in the world and killing millions in the process. After the approval of newly developed vaccines, severe challenges remain to manufacture and administer them to the adult population globally in quick time. However, we have witnessed several mutations of the virus leading to ‘waves’ of viral spread and mortality. WHO has categorized these mutations as variants of concern (VOCs) and variants of interest (VOIs). The mortality due to COVID-19 has also been associated with various comorbidities and improper immune response. This has created further complications in understanding the nature of the SARS-CoV2–host interaction that has fuelled doubts in the efficacy of the approved vaccines. Whether there is requirement of booster dose and whether the impending wave could affect the children are some of the hotly debated topics.

Materials and Methods

A systematic literature review of PubMed, Medline, Scopus, Google Scholar was utilized to understand the nature of Delta variant and how it alters our T-cell responses and cytokine production and neutralizes vaccine-generated antibodies.

Conclusion

In this review, we discuss the variants of SARS-CoV2 with specific focus on the Delta variant. We also specifically review the T-cell response against the virus and bring a narrative of various factors that may hold the key to fight against this marauding virus.

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.

Effectiveness of interleukin-4 administration or zinc supplementation in improving zinc deficiency-associated thymic atrophy and fatty degeneration and in normalizing T cell maturation process

Nutritional zinc deficiency induces thymic atrophy, but the underlying mechanisms remain unknown. In this study, we investigated the mechanism of thymic atrophy and fatty degeneration associated with zinc deficiency, and its effect on T cell maturation. Building on previous research demonstrating the beneficial effect of IL-4 administration or zinc supplementation on the spleen in zinc deficiency rats, we further examined whether these supplements also improve thymic atrophy. Five-week-old male Sprague-Dawley rats were fed a standard diet, zinc-deficient diet (n = 16 each) with either saline or IL-4, or a zinc-deficient diet for 6 weeks followed by a standard diet for 4 weeks. Relative thymus weights, serum thymulin concentrations, and the number of cytokeratin-8-positive cells, AIRE-positive cells, IL-7-positive cells, CD8⁺ T cells, CD4⁺ T cells, pre T cells, and CD25⁺ CD44⁺ (DN3) cells in the thymus of zinc deficiency rats significantly decreased compared with those in all other groups. Conversely, PPAR-γ-positive cells, oil red O-positive areas, pro T cells, CD25^- CD44⁺ cells, TUNEL positive cells, Viobility 405/452 Fixable Dye-positive cells, CD68-, CD163- or CD169- macrophages, and IL-1β concentrations were significantly increased in the thymus of zinc deficiency rats as compared to those in the other groups. After IL-4 administration or zinc supplementation for zinc deficiency, all the measurement indices were recovered to levels in standard rats. It was demonstrated that zinc deficiency caused thymic atrophy, accompanied by fatty degeneration in the cortical regions and affected T cell maturation. IL-4 administration or zinc supplementation for zinc deficiency ameliorated thymic fatty degeneration.

The Associations of Erythrocyte Fatty Acids with Whole Blood Mineral Elements in Children

Background. Minerals play important biological roles in lipid metabolism. The primary aim of this study was to examine the relationships between erythrocyte fatty acids (FAs) levels with whole blood mineral elements concentrations among Chinese children. Methods. A cross-sectional study was conducted. A total of 435 children aged 4−7 years were recruited. Whole blood mineral elements were determined by atomic absorption spectrometry and erythrocyte FAs composition by gas chromatography-mass spectrometer. Results. There were direct correlations between Zn and C18:2n-6 (FDR corrected p = 0.019), total n-6 PUFAs (FDR corrected p = 0.034), and total PUFAs (FDR corrected p = 0.034). Direct correlations were found between whole blood Zn and C18:1n-9 (FDR corrected p = 0.035), C24:1n-9 (FDR corrected p = 0.023), total MUFAs (FDR corrected p = 0.023), and C18:2n-6 (FDR corrected p = 0.048) in the Cu < P50 group. In the Cu ≥ P50 group, Mg was inversely related to most FAs (All FDR corrected p < 0.05). In the Zn < P50 group, Cu was directly related to C24:1n-9, total MUFAs, C20:5n-3, C22:6n-3, total n-3 PUFAs, C20:4n-6, total n-6 PUFAs, total PUFAs, and total FAs (All FDR corrected p < 0.05). Conclusions. Whole blood Cu and Zn levels were directly linked to several FAs levels in the erythrocytes of children. The interactions of Mg, Cu, and Zn with fatty acids may affect FA metabolism, in which Mg influences FA absorption.

Micronutrients for potential therapeutic use against COVID-19; a review

SARS CoV-2 has caused a pandemic that has challenged both clinicians and researchers in finding an effective treatment option. Currently there only exists a two series vaccine that has a high efficacy in preventing infection. There is no standard effective treatment against SARS CoV-2 however several nutraceuticals such as melatonin, zinc, selenium, vitamin C and vitamin D are being proposed as prevention and treatment options.

Zinc supplementation for prevention and management of recurrent aphthous stomatitis: a systematic review

BACKGROUND

Recurrent aphthous stomatitis (RAS) is a very common oral ulcerative disease with no definitive cure. Growing evidence suggests a significant association between zinc deficiency and RAS.

OBJECTIVES

To assess the efficacy of systemic zinc supplementations in the prevention and management of RAS.

METHODS

Five databases were searched for all English and Chinese studies published up to November 2020. All clinical trials that assessed the efficacy of zinc supplementations in the management and/or prevention of RAS were included.

RESULTS

Seven clinical trials comprising 482 RAS patients (250 in zinc group) fulfilled the inclusion criteria. The follow-up period ranged from three months to one year. Five studies showed significantly better efficacy of zinc in reducing the recurrence rates of RAS, whereas two studies did not report any significant differences compared to the controls. Four studies reported on signs/symptoms of RAS, three of which showed superior outcomes in favour of zinc, while one study reported comparable results.

CONCLUSION

Zinc supplementation seems to be efficacious in the management and prevention of RAS. However, further clinical trials with standardized methodologies and adequate follow-up periods are required to confirm the efficacy of zinc supplementations.

Adhesion of bioactive glass-based adhesive to bone

Understanding the failure modes and the fracture resistance is critical in evaluating the performance of an adhesive for sternal fixation. In this paper, a fracture mechanics testing methodology was used to assess the adhesion of a bioactive glass-based adhesive to bovine bone in terms of a measured mode I critical strain energy release rate (G_IC). Reinforced double cantilever beam (DCB) samples were observed to produce repeatable values of G_IC. The measured G_IC was found to increase significantly from 5.41 to 12.60 J/m² with an increase in adhesive thickness from 390 to 990 μm because of the constraint from the two adherends regulating the plastic zone size ahead of the crack. The specimens failed cohesively in all cases demonstrating that there was good adhesion to bone, a condition necessary to restrict micromotion and thus provide rigid sternal fixation when used along with sternal wires. It was also found that when the bone was flooded with liquid during adhesive application a much lower G_IC of between 0.69 and 1.15 J/m² was measured. Overall, the results demonstrate that the fracture mechanics approach can be used to provide a quantitative measure of the adhesion of the bioactive glass-based adhesive to the bone and that the adhesive should only be applied to clean bone in a dry environment.

Dietary Antioxidants in Age-Related Macular Degeneration and Glaucoma

Age-related macular degeneration (AMD) and glaucoma are ophthalmic neurodegenerative diseases responsible for irreversible vision loss in the world population. Only a few therapies can be used to slow down the progression of these diseases and there are no available treatment strategies for reversing the degeneration of the neural retina. In AMD, the pathological process causes the malfunction and damage of the retinal pigmented epithelium and photoreceptors in the macula. In glaucoma, damage of the retinal ganglion cells and their axons is observed and treatment strategies are limited to intraocular pressure lowering. Therefore, other prophylactic and/or therapeutic methods are needed. Oxidative stress is involved in the neurodegenerative process accompanying both AMD and glaucoma; therefore, the use of antioxidant agents would clearly be beneficial, which is supported by the decreased prevalence and progression of AMD in patients adherent to a diet naturally rich in antioxidants. Dietary antioxidants are easily available and their use is based on the natural route of administration. Many preclinical studies both in vitro and using animal models of retinal degeneration showed the efficacy of dietary antioxidants, which was further proved in clinical trials. Resveratrol is beneficial both in AMD and glaucoma animal models, but confirmed only among AMD patients. For AMD, carotenoids and omega-3 fatty acids were also proved to be sufficient in preventing neurodegeneration. For glaucoma, coenzyme Q10 and alpha-lipoic acid showed efficacy for decreasing retinal ganglion cell loss and inhibiting the accompanying destructive processes. Interestingly, the benefits of vitamins, especially vitamin E was not confirmed, neither in preclinical nor in clinical studies.

The Influence of Supplementation with Zinc in Micro and Nano Forms on the Metabolism of Fatty Acids in Livers of Rats with Breast Cancer

The aim of this study was to investigate the effect of zinc supplementation (in the form of nano or microparticles) on the profile and metabolism of fatty acids in the liver microsomes of rats with induced breast cancer. The activity of desaturases (Δ5, Δ6, Δ9) and the level of cholesterol and its oxidized derivatives were measured. The aim of this study was also to determine the effect of various forms of zinc supplements on rats that were on 5-, 12- and 15-hydroxyeicosatetraenoic (5-, 12- and 15-HETE) and hydroxyoctadecadienoic (HODE) acids, and the level of prostaglandin E2 (PGE2). Female Spraque-Dawley rats (n = 24) were divided into 2 groups that were supplemented with zinc in the micro form (342 nm) or nano form (99 nm) particles, respectively, and a group with a standard diet (control group). All animals received 7,12-dimethylbenz[a]anthracene twice for the induction of breast cancer. Dietary nano-Zn supplementation increased vaccenic acid content (p = 0.032) and decreased Δ6-desaturase activity (p = 0.006), whereas micro-Zn increased cholesterol (p = 0.006), ∑COPs (total cholesterol-oxidation products) (p = 0.019) and PGE2 (p = 0.028) content. Dietary enrichment with Zn microparticles resulted in lower concentrations of the metabolites 15-, 12- and 5-HETE and HODE. Our study indicates that the effect of zinc supplementation on the metabolism of fatty acids in the liver microsomes under neoplastic conditions depends on the form in which it is administered.

Zinc Deficiency, Plasma Fatty Acid Profile and Desaturase Activities in Hemodialysis Patients: Is Supplementation Necessary?

Background: Desaturation and elongation are critical processes in endogenous metabolic fatty acid pathways. Zinc (Zn) is a cofactor for desaturases and elongases enzymes. There is limited evidence regarding the relationships between biomarkers of Zn status, nutritional intake, plasma phospholipid fatty acid profile and clinical outcomes among patients undergoing hemodialysis (HD). Objective: To examine the relationships between dietary and serum levels of Zn and Cu/Zn ratio and to explore associations of these micronutrients with PUFA profile and estimated desaturase and elongase enzyme activities in serum phospholipids among HD patients. Methods: This study included 40 adult patients undergoing hemodialysis treatment. Repeated 24-h recalls were applied for dietary intake assessment. Serum concentration of Zn and Cu were determined using inductively coupled plasma mass spectrometry and fatty acid composition by gas-liquid chromatography. Desaturase and elongase activities were calculated from product-precursor fatty acid ratios. Results: Inadequate dietary Zn intake was found in 55% of HD patients. They all had serum Zn concentration below the reference value of 60 μg/dL (mean 38.8 ± 7.72 μg/dL). Adequate zinc intake was accompanied with significantly higher intake of energy, total fats, SFA, MUFA and proteins. There was no correlation between Zn serum status and Zn intake estimates. Serum Cu/Zn ratio was high, (2.76 ± 0.68), directly and significantly associated with HD period, CRP, BMI, VFA, and inversely with Kt/V, albumin, iron, and iPTH. The n-6/n-3 ratio in plasma phospholipids was elevated (12.25 ± 3.45) and patients with inadequate Zn intake had lower n-3 PUFA intake and status compared to those with adequate intake. Serum Zn concentrations were inversely correlated with linoleic/dihomo-γ-linolenic acid ratio (LA/DGLA) (p = 0.037), related to D6-desaturase activity (p = 0.033) and directly with DGLA relative abundances (p = 0.024). Cu status was inversely associated with EPA level (p = 0.03) and estimates of elongase activity (p = 0.001). Furthermore, positive relationship was found between the Cu/Zn ratio and determined elongase value (p = 0.01). Conclusion: Findings of this study underpin the high prevalence of Zn deficiency and inadequate n-3 PUFA intake and status among subjects undergoing HD. The results obtained indicate that the assessment of Zn status should be a standard parameter of nutritional status screening in HD patients while emphasizing the importance of Cu/Zn determination. Although further research is warranted, Zn and-n-3 PUFA supplementation in HD patients might be beneficial for the prevention and attenuation of adverse health outcomes.

Nanoencapsulation of thyme essential oil: a new avenue to enhance its protective role against oxidative stress and cytotoxicity of zinc oxide nanoparticles in rats

Although the green synthesis of nanometals is eco-friendly, the toxicity or safety of these biosynthesized nanoparticles in living organisms is not fully studied. This study aimed to evaluate the potential protective role of encapsulated thyme oil (ETO) against zinc oxide nanoparticles (ZnO-NPs). ETO was prepared using a mixture of whey protein isolate, maltodextrin, and gum Arabic, and ZnO-NPs were synthesized using parsley extract. Six groups of male Sprague-Dawley rats were treated orally for 21 days which included the control group, ZnO-NP-treated group (25 mg/kg body weight (b.w.)), ETO-treated groups at low or high dose (50, 100 mg/kg b.w.), and the groups that received ZnO-NPs plus ETO at the two tested doses. Blood and tissue samples were collected for different assays. The results showed that carvacrol and thymol were the major components in ETO among 13 compounds isolated by GC-MS. ZnO-NPs were nearly spherical and ETOs were round in shape with an average size of 38 and 311.8 nm, respectively. Administration of ZnO-NPs induced oxidative stress, DNA damage, biochemical, ctyogentical, and histological changes in rats. ETO at the tested doses alleviated these disturbances and showed protective effects against the hazards of ZnO-NPs. It could be concluded that encapsulation of thyme oil using whey protein isolate, maltodextrin, and gum Arabic improved the antioxidant properties of ETO, probably possess synergistic effects, and can be used as a promising tool in pharmaceutical and food applications.

Serum Zinc Levels and Incidence of Ischemic Stroke: The Reasons for Geographic and Racial Differences in Stroke Study

BACKGROUND AND PURPOSE

Despite zinc's role as an antioxidant and anti-inflammatory agent, prospective studies relating zinc levels to ischemic stroke risk are lacking. To examine the association between serum zinc levels and incidence of ischemic stroke in a US population.

METHODS

Using a case-cohort study nested within the Reasons for Geographic and Racial Differences in Stroke cohort, participants were randomly selected from the Reasons for Geographic and Racial Differences in Stroke cohort to generate a sub-cohort (n=2346). All incident ischemic stroke cases as of September 2012 (n=660) were included, with 62 incident cases overlapping in the sub-cohort. Serum zinc levels were measured at baseline. Barlow-weighted Cox's proportional hazards regression models were used to calculate multivariable-adjusted hazard ratios and the corresponding 95% CI of ischemic stroke by serum zinc levels.

RESULTS

The median zinc level for the sub-cohort was 121.19 µg/dL (interquartile range, 104.86-140.39 µg/dL). Serum zinc levels were inversely associated with incidence of ischemic stroke after adjustment for potential confounders (quartile 4 versus quartile 1: hazard ratio, 0.78 [95% CI, 0.61-0.98], P=0.03 for trend). When stratified by prespecified factors (sex, race, region), only sex showed a significant modification (P=0.03 for interaction). The inverse association was more pronounced among females (quartile 4 versus quartile 1: hazard ratio, 0.58 [95% CI, 0.41-0.84], P<0.01 for trend) than males (quartile 4 versus quartile 1: hazard ratio, 1.08 [95% CI, 0.78-1.51], P=0.92 for trend).

CONCLUSIONS

Serum zinc concentration was inversely associated with incidence of ischemic stroke, especially among women, indicating that low zinc levels may be a risk factor for ischemic stroke.

Is serum zinc status related to gestational diabetes mellitus? A meta-analysis

Gestational diabetes mellitus (GDM) is a common medical disorder that begins during pregnancy. The present work aimed to investigate the relationship of maternal or foetal circulatory zinc levels with GDM. Related studies were retrieved against the PubMed/Medline, Web of Science, Scopus databases till July 2020. The overall effects were expressed as standard mean difference (SMD). Furthermore, the random effects model was used to assess the summarised risk ratios (SRRs) to determine the relationship between zinc and the risk of GDM. A total of 15 articles involving were retrieved for meta‐analysis; in the meantime, 4955 subjects including 1549 GDM cases were enrolled for quantitative analysis. Compared with normal control, GDM cases had decreased circulating zinc level on the whole, but the difference was not statistically significant (SMD = −0.40, 95%CI: −0.80 to −0.00, P = 0.05). Interestingly, upon subgroup analysis stratified by serum zinc content but not plasma zinc concentration, there was significant difference in zinc content between GDM cases and normal controls (SMD = −0.56; 95%CI: −1.07 to −0.04, P = 0.03). Meanwhile, subgroup analysis also revealed similar tendency among the Asians and during the 2nd trimester, but not among the Caucasians or during the 1st or 3rd trimester. Data extracted from four studies that compared pregnant women with GDM in the high level of zinc and GDM in the low level of zinc yielded an SRR of 0.929 (95%CI: 0.905–0.954). According to existing evidence, the serum zinc content decreases among GDM cases compared with subjects with no abnormality in glucose tolerance, in particular among the Asians and during the second trimester. Nonetheless, more well designed prospective study should be carried out for understanding the dynamic relationship of zinc level with the incidence of GDM.

Zinc and COVID-19: Basis of Current Clinical Trials

Coronavirus disease-2019 (COVID-19) pandemic continues to threaten patients, societies, and economic and healthcare systems around the world. Like many other diseases, the host immune system determines the progress of COVID-19 and fatality. Modulation of inflammatory response and cytokine production using immunonutrition is a novel concept that has been applied to other diseases as well. Zinc, one of the anti-inflammatory and antioxidant micronutrient found in food with well-established role in immunity, is currently being used in some clinical trials against COVID-19. This review integrates the contemporary studies of role of zinc in antiviral immunity along with discussing its potential role against COVID-19, and ongoing COVID-19 clinical trials using zinc.

Dysregulation of metallothionein and zinc aggravates periodontal diseases

BACKGROUND

Periodontitis (PD) is a multifaceted inflammatory disease connected to bacterial infection that results in the destruction of tooth supporting structures and eventually tooth loss. Given their involvement in infection and inflammation, both metallothionein (MT) and zinc (Zn) might play vital roles in the development and progression of PD. More specifically, both MT and Zn are heavily involved in regulating immune functions, controlling bacterial infection, balancing inflammatory responses, and reducing oxidative stress, all of which are associated with the pathogenesis of PD.

OBJECTIVE

This review paper will explore the physiological functions of MT and Zn and hypothesise how dysregulation could negatively affect periodontal health, leading to PD.

FINDINGS

Bacterial lipopolysaccharide (LPS) derived from periodontal pathogens, namely P. gingivalis initiates the acute phase response, thus upregulating the expression of MT which leads to the subsequent deficiency of Zn, a hallmark of periodontal disease. This deficiency leads to ineffective NETosis, increases the permeability of the gingival epithelium, and disrupts the humoral immune response, collectively contributing to PD. In addition, the presence of LPS in Zn deficient conditions favours M1 macrophage polarisation and maturation of dendritic cells, and also inhibits the anti-inflammatory activity of regulatory T cells. Collectively, these observations could theoretically give rise to the chronic inflammation seen in PD.

CONCLUSION

A disrupted MT and Zn homeostasis is expected to exert an adverse impact on periodontal health and contribute to the development and progression of PD.