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Alzheimer's disease (AD) has no cure, mainly because of late diagnosis. Early diagnostic biomarkers are crucial. Phospholipases A

Epidemiologic studies suggest that exposure to Cd is related to a multitude of age-related diseases. There is evidence that Cd toxicity emerges from an interference with Zn metabolism as they compete for the same binding sites of ligands. The most responsive proteins to Cd exposure are the metal-binding proteins termed metallothioneins (MTs), which display a much greater affinity for Cd than for Zn. Most studies have considered the effect of Zn on the accumulation of exogenous Cd and tissue damage, whereas observational studies have addressed the association between Zn intake and Cd levels in body fluids. However, it has not been addressed whether supplemental Zn can lower Cd levels in organs of healthy aged animals without affecting Cu stores, a question more pertinent to human aging. We therefore aimed to investigate the effect of Zn supplementation on Cd levels in liver and kidney of aged MT transgenic mice (MT1-tg) overexpressing MT1 at levels more comparable to those observed in humans than non-transgenic mice. We found a >30% reduction of kidney and liver Cd levels in Zn supplemented MT1-tg mice compared to non-supplemented controls, independently of the dose of Zn, without a significant reduction of Cu. Our data support the idea of a causal and inverse relationship between Zn intake and Cd content in organs of aged MT1-tg mice as suggested by observational studies in humans. Our work provides the rationale for interventional studies to address the effects of Zn supplementation on Cd burden in elderly people.

The analysis of copper (Cu) and zinc (Zn) along with their major serum carriers, albumin (Alb) and ceruloplasmin (Cp), could provide information on the capacity of humans to maintain homeostasis of metals (metallostasis). However, their relationship with aging, sex, body mass index, as well as with nutritional and inflammatory markers was never investigated in a large-scale study. Here, we report results from the European large-scale cross-sectional study MARK-AGE in which Cu, Zn, Alb, Cp, as well as nutritional and inflammatory parameters were determined in 2424 age-stratified participants (35–75 years), including the general population (RASIG), nonagenarian offspring (GO), a well-studied genetic model of longevity, and spouses of GO (SGO). In RASIG, Cu to Zn ratio and Cp to Alb ratio were higher in women than in men. Both ratios increased with aging because Cu and Cp increased and Alb and Zn decreased. Cu, Zn, Alb, and Cp were found associated with several inflammatory as well as nutritional biomarkers. GO showed higher Zn levels and higher Zn to Alb ratio compared to RASIG, but we did not observe significant differences with SGO, likely as a consequence of the low sample size of SGO and the shared environment. Our results show that aging, sex, body mass index, and GO status are characterized by different levels of Cu, Zn, and their serum carrier proteins. These data and their relationship with inflammatory biomarkers support the concept that loss of metallostasis is a characteristic of inflammaging.

Impaired zinc homeostasis is observed in diabetes mellitus (DM2) and its complications. Zinc has a specific role in pancreatic β-cells via insulin synthesis, storage, and secretion. Intracellular zinc homeostasis is tightly controlled by zinc transporters (ZnT and Zip families) and metallothioneins (MT) which modulate the uptake, storage, and distribution of zinc. Several investigations in animal models demonstrate the protective role of MT in DM2 and its cardiovascular or renal complications, while a copious literature shows that a common polymorphism (R325W) in ZnT8, which affects the protein's zinc transport activity, is associated with increased DM2 risk. Emerging studies highlight a role of other zinc transporters in β-cell function, suggesting that targeting them could make a possible contribution in managing the hyperglycemia in diabetic patients. This article summarizes the current findings concerning the role of zinc homeostasis in DM2 pathogenesis and development of diabetic cardiomyopathy and nephropathy and suggests novel therapeutic targets. © 2017 BioFactors, 43(6):770-784, 2017.

Zinc dyshomeostasis may lead to an augmented production of proinflammatory cytokines promoting chronic inflammation and increasing the susceptibility to age-related diseases. Several studies suggest that the zinc transporter protein ZIP2 may play a relevant role in the immune system especially during zinc deficiency, while a polymorphism on the coding region of ZIP2 gene (Gln/Arg/Leu) has been associated with severe carotid artery disease. The aim of this study is to investigate the role of ZIP2 SNP on zinc and inflammatory status in 1090 elderly healthy free-living subjects enrolled in the ZincAge project and to assess the effect of zinc supplementation on zinc status, inflammatory mediators, and zinc transporter expression depending on ZIP2 genotype. ZIP2 Leu- (Arg43Arg) carriers showed enhanced IL-6, TNF-α, and RANTES plasma levels associated with decreased free cytosolic zinc in PBMCs and an upregulation of zinc transporters ZIP2, ZIP8, and Znt1. Moreover, Leu- subjects displayed significant decrement of inflammatory mediators such as MCP-1, TNF-α, and RANTES following zinc supplementation. In summary, this investigation provides new evidence on the effect of ZIP2 Gln/Arg/Leu polymorphism on proinflammatory mediators and zinc homeostasis in elderly population with a more pronounced anti-inflammatory effect of zinc supplementation in subjects carrying ZIP2 Leu- (Arg43Arg) genotype. These novel findings could be useful in identifying elderly subjects who may benefit of zinc intervention to decrease the inflammatory status and to prevent or delay the development of age-related diseases.

The serum concentrations of copper (Cu) and zinc (Zn) are strictly regulated by compensatory mechanisms that act to stabilize them within certain ranges of nutritional intake. However, there are mechanisms that are built to decrease serum concentration of Zn and to increase serum concentration of Cu in the presence of inflammatory conditions, so that a common feature of several age-related chronic diseases is an increase of the Cu to Zn ratio (CZr). Although the clinical potential of CZr has been extensively investigated, few authors addressed the mechanisms that mainly contribute to the increase of CZr in serum during aging, which signals drive this change and how cells respond to these changes. This review focuses on this topic and discusses how an increase of CZr during aging could reflect the homeostatic shade from a general systemic "growth and reproduction" status typical of juvenile age to a "repair and maintenance" status that evolved to preserve health status during old age.

Metallothionein (MT) family are cysteine-rich proteins that regulate zinc (Zn) homeostasis and protect against oxidative damage. Studies in transgenic mice have shown that MT favorably influence longevity, although their role in human aging is not completely understood. Within the European multicenter study MARK-AGE, we analyzed MT induction after Zn treatment in peripheral blood mononuclear cells (PBMCs) and its relation with redox biomarkers in 2,936 age-stratified subjects (35–75 years) including the general population (RASIG), centenarian offspring (GO), and their spouses (SGO). We found that the lymphocyte capability to induce MT in response to Zn is not affected by aging. However, GO participants showed lower Zn-induced MT and increased basal expression of MT1A, MT1X, and ZnT-1 genes than RASIG subjects. Moreover, Zn-induced MT levels were found to be inversely related with oxidative stress markers (plasma protein carbonyls, 3-nitrotyrosine, and malondialdehyde) in the whole population, but not in GO subjects. In conclusion, our results support the hypothesis that the response to Zn is attenuated in PBMCs of centenarian offspring compared to the general population as a consequence of a tighter control of Zn homeostasis which is likely to provide them constant protection against stress stimuli over the whole lifespan. published

Exosomes are nanovesicles known to mediate intercellular communication. Although it is established that zinc ions can act as intracellular signaling factors, the measurement of zinc in circulating nanovesicles has not yet been attempted. Providing evidence of the existence of this zinc fraction and methods for its measurement might be important to advance our knowledge of zinc status and its relevance in diseases. Exosomes from 0.5 ml of either fresh or frozen human plasma were isolated by differential centrifugation. A morphological and dimensional evaluation at the nanoscale level was performed by atomic force microscopy (AFM) and Transmission Electron Microscopy (TEM). Energy Dispersive X-Ray Microanalysis (EDX) revealed the elemental composition of exosomes and their respective total Zinc content on a quantitative basis. The zinc mole fraction (in at%) was correlated to the phosphorous mole fraction, which is indicative for exosomal membrane material. Both fresh (Zn/P 0.09 ± 0.01) and frozen exosomes (Zn/P 0.08 ± 0.02) had a significant zinc content, which increased up to 1.09 ± 0.12 for frozen exosomes when treated with increasing amounts of zinc (100-500 μM; each p 0.05). Interestingly, after zinc addition, the Calcium mole fractions decreased accordingly suggesting a possible exchange by zinc. In order to estimate the intra-exosomal labile zinc content, an Imaging Flow Cytometry approach was developed by using the specific membrane permeable zinc-probe Fluozin-3AM. A labile zinc content of 0.59 ± 0.27 nM was calculated but it is likely that the measurement may be affected by purification and isolation conditions. This study suggests that circulating nano-vesicular-zinc can represent a newly discovered zinc fraction in the blood plasma whose functional and biological properties will have to be further investigated in future studies.

Impaired zinc homeostasis is observed in diabetes mellitus (DM2) and its complications. Zinc has a specific role in pancreatic β-cells via insulin synthesis, storage, and secretion. Intracellular zinc homeostasis is tightly controlled by zinc transporters (ZnT and Zip families) and metallothioneins (MT) which modulate the uptake, storage, and distribution of zinc. Several investigations in animal models demonstrate the protective role of MT in DM2 and its cardiovascular or renal complications, while a copious literature shows that a common polymorphism (R325W) in ZnT8, which affects the protein's zinc transport activity, is associated with increased DM2 risk. Emerging studies highlight a role of other zinc transporters in β-cell function, suggesting that targeting them could make a possible contribution in managing the hyperglycemia in diabetic patients. This article summarizes the current findings concerning the role of zinc homeostasis in DM2 pathogenesis and development of diabetic cardiomyopathy and nephropathy and suggests novel therapeutic targets. © 2017 BioFactors, 43(6):770-784, 2017.

Recent longitudinal studies in dietary daily intake in human centenarians have shown that a satisfactory content of some micronutrients within the cells maintain several immune functions, a low grade of inflammation and preserve antioxidant activity. Micronutrients (zinc, copper, selenium) play a pivotal role in maintaining and reinforcing the performances of the immune and antioxidant systems as well as in affecting the complex network of the genes (nutrigenomic) with anti- and pro-inflammatory tasks. Genes of pro- and anti-inflammatory cytokines and some key regulators of trace elements homeostasis, such as Metallothioneins (MT), are involved in the susceptibility to major geriatric disease/disorders. Moreover, the genetic inter-individual variability may affect the nutrients’ absorption (nutrigenetic) with altered effects on inflammatory/immune response and antioxidant activity. The interaction between genetic factors and micronutrients (nutrigenomic and nutrigenetic approaches) may influence ageing and longevity because the micronutrients may become also toxic. This review reports the micronutrient–gene interactions in ageing and their impact on the healthy state with a focus on the method of protein–metal speciation analysis. The association between micronutrient–gene interactions and the protein–metal speciation analysis can give a complete picture for a personalized nutrient supplementation or chelation in order to reach healthy ageing and longevity.

Proinflammatory cytokines and heat shock proteins play relevant roles in the pathogenesis of inflammatory diseases. We investigated whether Hsp70 1267 A/G and TNF-α -308 G/A polymorphisms are associated with proinflammatory mediators, zinc status and laboratory parameters in 1,078 healthy elderly from ZincAge study. Hsp70 1267 A/G genotype and allele distribution were similar among various European countries, while a TNF-α genetic heterogeneity was observed between the Northern and the Southern European populations, with a major frequency of the -308 A variant in France, Germany and Poland. We used linear regression models to test additive, dominant or recessive associations of each SNP with proinflammatory mediators, laboratory parameters, metallothioneins and zinc status. Hsp70 1267 A/G SNP, but not TNF-α -308 G/A SNP, influences TNF-α and IL-6 plasma levels under additive, dominant and recessive models (for TNF-α only). An association between Hsp70 1267 A/G SNP and zinc plasma levels was observed in the dominant model. In particular, G allele carriers showed increased circulating pro-inflammatory cytokines and zinc. Moreover, both these SNPs affect creatinine levels suggesting a possible influence on renal function. In conclusion, Hsp70 1267 A/G SNP is associated with pro-inflammatory cytokine production in healthy elderly and might represent a possible determinant of individual susceptibility to inflammatory diseases.

Disturbances of zinc homeostasis have been observed in several diseases, including diabetes mellitus. To further characterize the association between zinc and diabetes, we recruited 75 patients with type 1 or type 2 diabetes and 75 nondiabetic sex-/age-matched control subjects in order to analyze differences concerning human zinc transporter 8 (hZnT-8) expression, single nucleotide polymorphisms (SNPs) in the genes of hZnT-8 as well as metallothionein 1A and serum/intracellular zinc. Furthermore, we investigated the relation between insulin and zinc homeostasis in type 2 diabetic subjects and consolidated our results by in vitro analysis of the effect of insulin on cellular zinc status and by analysis of the modulation of insulin signal transduction by intracellular zinc homeostasis. Concerning the expression of hZnT-8 and the SNPs analyzed, we did not observe any differences between diabetic and control subjects. Serum zinc was significantly lower in diabetic patients compared to controls, and intracellular zinc showed the same tendency. Interestingly, type 2 diabetes patients treated with insulin displayed lower serum zinc compared to those not injecting insulin. In vitro analyses showed that insulin leads to an increase in intracellular zinc and that insulin signaling was enhanced by elevated intracellular zinc concentrations. In conclusion, we show that type 1 and type 2 diabetic patients suffer from zinc deficiency, and our results indicate that zinc supplementation may qualify as a potential treatment adjunct in type 2 diabetes by promoting insulin signaling, especially in zinc-deficient subjects.

Ageing is an inevitable biological process associated with gradual and spontaneous biochemical and physiological changes and increased susceptibility to diseases. Nutritional factor, zinc, known to be involved in improving immunity, may remodel some of the age-associated changes, leading to a healthy ageing. "In Vitro" studies involving human lymphocytes exposed to endotoxins, and "in vivo" studies comparing old and young mice fed with low dietary zinc suggest that zinc is important for both innate and adaptive immune efficiency, and more optimal inflammatory/immune response. The intracellular zinc homeostasis is mainly regulated by Metallothioneins (MT), via ion release through the reduction of thiol groups in MT molecule. These processes are crucial because mediating the zinc signalling within the immune cells assigning to zinc a role of "second messenger". Zinc homeostasis is altered in ageing partly due to higher expression levels of MT, leading to an increased sequestration of zinc, resulting in less availability of free intracellular zinc. Improvement of immune functions and stress response systems occurs in elderly after physiological zinc supplementation. The main reason behind these effects seems to be related to a like "hormetic" response induced by zinc. However, the choice of old subjects for zinc supplementation has to be performed in relationship to the specific genetic background of MT and pro-inflammatory cytokine (IL-6) because the latter is involved both in MT gene expression and in intracellular zinc homeostasis. Old subjects carrying GG genotypes (termed C- carriers) in IL-6--174G/C locus display increased IL-6 production, low intracellular zinc ion availability, impaired innate immune response and enhanced MT. By contrast, old subjects carrying GC and CC genotypes (termed C+ carriers) in the same IL-6--174 locus displayed satisfactory intracellular zinc and innate immune response. Moreover, male carriers of C+ allele are more prone to reach centenarian age than C- ones. Therefore, old C- subjects are likely to benefit more from zinc supplementation restoring NK cell cytotoxicity and improving the zinc status. Plasma zinc deficiency and the altered immune response is more evident when the genetic variations of IL-6 polymorphism are associated with the genetic variations of MT1A in position +647, suggesting that the genetic variations of IL-6 and MT1A are very useful tools for the identification of old people who effectively need zinc supplementation.

Ageing is an inevitable biological process with gradual and spontaneous biochemical and physiological changes and increased susceptibility to diseases. The nutritional factor, zinc, may remodel these changes with subsequent healthy ageing, because zinc improves the inflammatory/immune response as shown by in vitro and in vivo studies. The intracellular zinc homeostasis is regulated by buffering metallothioneins (MT) and zinc transporters (ZnT and ZIP families) that mediate the intracellular zinc signalling assigning to zinc a role of ‘second messenger’. In ageing, the intracellular zinc homeostasis is altered, because high MT are unable to release zinc and some zinc transporters deputed to zinc influx (ZIP family) are defective leading to low intracellular zinc content for the immune efficiency. Physiological zinc supplementation in the elderly improves these functions. However, the choice of old subjects for zinc supplementation has to be performed in relation to the specific genetic background of MT and IL-6, because the latter is involved both in MTmRNA and in intracellular zinc homeostasis. Old subjects carrying GG genotypes (C–carriers) in the IL-6–174G/C locus display high IL-6, low intracellular zinc content, impaired innate immunity and enhanced MT. Old subjects carrying GC and CC genotypes (C+carriers) display satisfactory intracellular zinc content, adequate innate immunity and are more prone to reach longevity. Zinc supplementation in old C–carriers restores natural killer cell cytotoxicity and zinc status. The genetic variations of the IL-6−174G/C locus when associated with those of the MT1A+647A/C locus are useful tools for the choice of old people for zinc supplementation.

Overweight and obesity are associated with low grade of inflammation and chronic inflammatory response characterized by abnormal production and activation of some pro-inflammatory signalling pathways. Taking into account that obesity is the direct result of an imbalance between energy intake and energy expenditure, the nutritional factors in the diet, with particular focus on zinc, may play a pivotal role in the development of obesity-associated comorbidities. Considering the potential interactions among zinc nutritional status, inflammation, overweight/obesity and insulin secretion, the aim of the present work was to clarify the influence of zinc dietary intake on some metabolic, inflammatory and zinc status parameters in adult overweight/obese subjects. We found a close interrelationship between nutritional zinc and obesity. In particular, subjects with a lower zinc dietary intake display a deeper inflammatory status, general impairment of the zinc status, an altered lipid profile and increased insulin production with respect to obese subjects with normal zinc dietary intake. Moreover, in the presence of low dietary zinc intake, the obese subjects are less capable to respond to oxidative stress and to inflammation leading to the development of obesity or to a worsening of already preexisting obesity status. In conclusion, a possible zinc supplementation in obese subjects with a deeper inflammatory status and more altered zinc profile may be suggested in order to limit or reduce the inflammation, taking also into account that zinc supplementation normalizes "inflammaging" as well as zinc profile leading to a correct intra- and extracellular zinc homeostasis.

Associations have been reported between plasma Cu and Zn levels and the incidence of the most important age-related diseases. Previously proposed methods of using plasma Cu/Zn as a predictor of all-cause mortality have been derived from populations in which old and very old subjects were underrepresented. The purpose of this paper is to estimate the usefulness of plasma Cu/Zn as a sensitive biomarker of harmful inflammatory or nutritional changes in the elderly and its incremental prognostic utility as a predictor of all-cause mortality in a functionally independent elderly Italian cohort. The association between plasma Cu/Zn and inflammatory (CRP, ESR, IL-6) or nutritional (albumin, BMI) markers was studied in 498 elderly subjects. Blood samples were taken from 164 healthy 20- to 60-year-old volunteer controls. A 3.5 years prospective follow-up study of mortality by age-related diseases was performed in n = 218 over 70-year-olds. Plasma Cu/Zn ratio was associated with all the inflammatory markers studied, as well as with serum albumin, and predicted 3.5 years mortality in subjects over 70. Plasma Cu/Zn was higher in women than men and increased with advancing age. Subjects with stable cardiovascular disease (CVD) displayed higher plasma Cu/Zn than those without, due mainly to increased plasma Cu. However, most of the age-related changes of Cu/Zn resulted from a progressive decline of plasma Zn. Cu/Zn ratio may be considered an important clinical inflammatory-nutritional biomarker as well as a significant predictor of all-cause mortality in over 70-year-olds.

During aging, dysregulated immune functions occur contributing to increased susceptibility to morbidity and mortality. However, these dysregulations are normally counterbalanced by continuous adaptation of the body to the deteriorative changes occurring over time. These adaptive changes well occur in healthy centenarians.Both innate (natural) and adaptive (acquired) immune responses decline with advancing age. Natural killer (NK) and natural killer T (NKT) cell cytotoxicity, representing one of best models of innate immune response, decreases in aging as well as interferon-gamma (IFN-gamma) production by both activated types of cells. Both NK and NKT cell cytotoxicity and IFN-gamma production increase in very old age with respect to normal aging, especially by NKT cells bearing TCRgammadelta. The role played by zinc and metallothioneins (MT) is crucial because this affects NK and NKT cell development, maturation, and functions. In particular, some MT polymorphisms are involved in maintaining innate immune response and intracellular zinc ion availability in aging with thus a role of MT genetic background to escape some age-related diseases with subsequent healthy aging and longevity.

Critical shortening of telomeres, likely associated with a considerable increase of senescent cells, can be observed in PBMC of individuals aged 80 and older. We investigated the relationship between critical telomere shortening and zinc status in healthy or hypertensive participants with or without cardiovascular disease in old and very old participants. Telomere shortening and accumulation of cells with short telomeres (percent of cells with short telomeres) in advancing age was evident in patients and healthy controls, but exacerbated in those patients aged 80 and older. Moreover, in very old patients, the accumulation of % CST may impair intracellular zinc homeostasis and metallothioneins expression, which itself is linked to an increased number of inflammatory agents, thereby suggesting the existence of a possible causal relationship between % CST and zinc homeostasis. The determination of % CST could be a more reliable means than the simple measure of telomere length as fundamental parameter in ageing to determine whether individuals are still able to respond to stress.

A finely tuned subcellular distribution of zinc (Zn), through the coordinated action of Zn transporters (ZnTs) and metallothioneins (MTs), is crucial for optimal cell function. Dysfunctions of these proteins might act as key causative or promoting factors in several chronic pathologies. Evidence of their involvement in the pathogenesis of type 2 diabetes (DM2) is emerging. The association of single nucleotide polymorphisms in genes encoding ZnT-8 and MT with DM2 has drawn attention to the relevance of Zn homeostasis for insulin secretory capacity and responsiveness. Here, we propose that potential mechanisms leading to altered subcellular Zn distribution rather than deficiency might be important in DM2. Increasing knowledge of the mechanisms of Zn homeostasis and signalling should promote the development of targeted interventions with the potential to reduce the burden of disease.

Diabetes mellitus is a chronic disease characterized by an overproduction of reactive oxygen species, which perturbs zinc metabolism and promotes the onset of cardiovascular disease (CVD) in diabetic patients. Metallothioneins (MT) are cysteine-rich metal-binding proteins which, by means of their antioxidant and zinc-buffering properties, might prevent the development of diabetic cardiovascular complications. A recent investigation shows that a polymorphism (+647 A/C) in the human MT-1A gene, affects the intracellular zinc ion release (iZnR) from the proteins and is associated with longevity in Italian population. The aim of the present study is to assess the involvement of +647 A/C and +1245 A/G MT1A polymorphisms with the susceptibility to type 2 diabetes (DM2) and cardiovascular complications. The study included 694 old individuals: 242 old healthy controls, 217 DM2 patients without clinical evidence of CVD (DNC) and 235 diabetic patients with diagnosis of CVD (DCVD). +647 A/C MT1A polymorphism, but not the second SNP, was associated with DM2. C allele carriers were more prevalent in DNC and DCVD patients than in control group (OR=1.37, p=0.034; OR=1.54, p=0.002, respectively). C+ carriers was associated with higher glycemia and glycosylated hemoglobin in DCVD patients, but not in DNC or control subjects. No differences in plasma zinc, but a modulation of MT levels and iZnR in PBMCs were observed in DCVD cohort when related to +647 A/C MT1A polymorphism. In summary, this work provides novel evidence on the association of the +647 A/C MT1A polymorphism with DM2. Moreover, C+ carriers in DCVD patients presented a worse glycemic control, a reduced iZnR and a higher MT levels, suggesting a possible role of MT in diabetic cardiovascular complications.

Mild zinc deficiency, which is prevalent in vegetarians, diseased individuals, and the general aging population, depresses immunity and increases risk of disease in later life. However, human zinc intervention trials have produced conflicting results, perhaps because many of these trials included young or zinc-sufficient subjects. Since heterogeneity of the adult population may impact on response to dietary zinc, nutrigenomic approaches aimed at understanding the impact of zinc on modulation of gene and protein activities may aid in identifying subsets of the population-in particular the aging population-with increased risk of zinc deficiency who might receive benefit from a dietary zinc intervention and in this way may influence the success of the intervention. In the current study we used nutrigenomic approaches to investigate the impact of age on zinc-regulated gene expression in peripheral blood mononuclear cells. Ingenuity Pathway Analysis (Ingenuity Systems, Redwood City, CA) identified several genetic networks and functional canonical pathways which appeared responsive to zinc that were differentially regulated in young and elderly individuals. These include tryptophan metabolism, eicosanoid signaling, p38 mitogen-activated protein kinase (MAPK) signaling, integrin signaling, purine metabolism, G-protein-coupled receptor signaling, and most significantly, peroxisome proliferator-activated receptor (PPAR) signaling. These data suggest that age impacts strongly on the transcriptional effects of zinc and provides evidence to support the hypothesis that young and elderly individuals may respond differentially to zinc intervention.

Aging is an inevitable biological process that is associated with gradual and spontaneous biochemical and physiological changes and increased susceptibility to diseases. Because nutritional factors are involved in improving immune functions, metabolic harmony, and antioxidant defense, some nutritional factors, such as zinc, may modify susceptibility to disease and promote healthy aging. In vitro (human lymphocytes exposed to endotoxins) and in vivo (old or young mice fed with low zinc dietary intake) studies revealed that zinc is important for immune efficiency (innate and adaptive), antioxidant activity (supeoxide dismutase), and cell differentiation via clusterin/apolipoprotein J. Intracellular zinc homeostasis is regulated by metallothioneins (MT) via ion release through the reduction of thiol groups in the MT molecule. This process is crucial in aging because high MT levels are not able to release zinc, resulting in low intracellular free ion availability for biological functions. Improvement in these functions occurs in the elderly after physiological zinc supplementation. In this study, the selection of elderly subjects for zinc supplementation is discussed in relation to the genetic background of MT and pro-inflammatory cytokines, such as interleukin-6, because the latter is involved both in MT-gene expression and in intracellular zinc homeostasis.

Carotid artery stenosis (CS) is a well-established risk factor for stroke. Increased proinflammatory chemokines, enhanced metallothionein (MT), and altered metal homeostasis may play roles in atherosclerosis progression and plaque destabilization. MT may sequester zinc during chronic inflammation, provoke zinc deficiency, and modulate NK cell cytotoxicity. A recent investigation of older patients with diabetes and atherosclerosis showed an association between the −209 A/G MT2A polymorphism, CS, and zinc status. In this study, we evaluated the relationship between two MT2A polymorphisms (−209 and + 838 locus), metal status, and inflammatory/immune response in older patients with CS only (the CS1 group) or with CS and previous cerebrovascular episodes (transient ischemic attack or stroke) (the CS2 group). A total of 506 individuals (188 CS1, 100 CS2, and 218 healthy controls) were studied. Atherosclerotic patients (CS1 and CS2) showed increased levels of MT, MCP-1, and RANTES, reduced NK cell cytotoxicity, and altered trace element concentrations (zinc, copper, magnesium, iron). The +838 C/G MT2A polymorphism was differently distributed in CS1 and CS2 patients, who displayed the GG genotype (C−) with significantly higher frequency than elderly controls. C− carriers showed increased MCP-1 and decreased NK cell cytotoxicity, CD56+ cells, and intracellular zinc availability along with decreased zinc, copper, and magnesium content in erythrocytes and increased iron in plasma. C− carriers also showed a major incidence of soft carotid plaques. In conclusion, the +838 C/G MT2A polymorphism seems to influence inflammatory markers, zinc availability, NK cell cytotoxicity, and trace element status, all of which may promote CS development.

Zinc dyshomeostasis may lead to an augmented production of proinflammatory cytokines promoting chronic inflammation and increasing the susceptibility to age-related diseases. Several studies suggest that the zinc transporter protein ZIP2 may play a relevant role in the immune system especially during zinc deficiency, while a polymorphism on the coding region of ZIP2 gene (Gln/Arg/Leu) has been associated with severe carotid artery disease. The aim of this study is to investigate the role of ZIP2 SNP on zinc and inflammatory status in 1090 elderly healthy free-living subjects enrolled in the ZincAge project and to assess the effect of zinc supplementation on zinc status, inflammatory mediators, and zinc transporter expression depending on ZIP2 genotype. ZIP2 Leu- (Arg43Arg) carriers showed enhanced IL-6, TNF-α, and RANTES plasma levels associated with decreased free cytosolic zinc in PBMCs and an upregulation of zinc transporters ZIP2, ZIP8, and Znt1. Moreover, Leu- subjects displayed significant decrement of inflammatory mediators such as MCP-1, TNF-α, and RANTES following zinc supplementation. In summary, this investigation provides new evidence on the effect of ZIP2 Gln/Arg/Leu polymorphism on proinflammatory mediators and zinc homeostasis in elderly population with a more pronounced anti-inflammatory effect of zinc supplementation in subjects carrying ZIP2 Leu- (Arg43Arg) genotype. These novel findings could be useful in identifying elderly subjects who may benefit of zinc intervention to decrease the inflammatory status and to prevent or delay the development of age-related diseases.

Metallothioneins (MTs) play a pivotal role in zinc-related cell homeostasis because of their high affinity for zinc, which is in turn fundamental for immune response and antioxidant activity. MTs regulate zinc homeostasis by binding zinc and releasing zinc at the occurrence for immune response. The zinc release by MT is very limited in chronic inflammation and ageing. Some polymorphisms of MTs gene, in particular MT1a sub-isoform, may affect this release that is a problem still unresolved in ageing. The screening in the present paper of two polymorphisms in MT1a gene has revealed for the first time that the polymorphism corresponding to a A/C (Asp/Thr) transition at 647 nt position in the Mt1a coding region is the more involved in the longevity, at least in old women, rather than the other corresponding to A/G (Lys/Arg) transition at 1,245 nt position. Concomitantly, for the +647 MT1a polymorphism, old and very old female with Asp/Asp genotype (called C-carriers) display higher zinc release by MT (detected by Zinpyr-1 fluorescent probe in presence of NO donor), low MT levels and reduced IL-6 plasma concentrations, suggesting its involvement in longevity and in lower inflammatory status. This fact is confirmed by the analysis of haplotypes in which the allele Asp is more involved in longevity. Therefore the +647 MT1a polymorphism more affects MTs induction and zinc release, which are indispensable to undertake the inflammatory status under control and subsequently to reach healthy longevity.

Proteins involved in zinc homeostasis may be altered in aging. This phenomenon may lead to zinc deficiency in the peripheral blood and an accumulation of zinc bound to insoluble aggregates at the extracellular level in the brain. Therefore, it should be more correct to talk about aging as a condition associated with zinc dyshomeostasis rather than deficiency. Restoring functional zinc homeostasis in aging people is an attractive field for antiaging research, but requires further knowledge than the current state of the art.

Vascular complications, including ischaemic cardiomyopathy, are the major causes of death in old diabetic patients. Chronic inflammation due to high IL-6 production occurs in type 2 diabetes (NIDDM) and atherosclerosis. High levels of IL-6 are associated with hyperglycaemia, dyslipidemia and provoke insulin resistance. In ageing and inflammation, IL-6 affects Metallothionein (MT) homeostasis, which in turn is involved in zinc turnover. Zinc deficiency is an usual event in ageing, inflammation, type 2 diabetes and atherosclerosis. No genetic study exists on MT polymorphisms in NIDDM-atherosclerotic patients. The aim of the present study is to screen a single nucleotide polymorphism in the promoter region of the MT2A gene in relation to inflammation (IL-6) and plasma zinc in NIDDM-atherosclerotic patients. The -209 A/G MT2A polymorphism is associated with chronic inflammation (higher plasma levels of IL-6), hyperglycaemia, enhanced HbA1c and more marked zinc deficiency in AA than AG genotype carrying patients. Analysing patients and controls subdivided in AA and AG genotypes, significant interactions existed between disease status and genotypes for glucose and zinc. AA patients are more at risk of developing NIDDM in association with atherosclerosis (p = 0.0015 odds ratio = 2.617) and its complications, such as ischaemic cardiomyopathy (p = 0.0050 odds ratio = 12.6). In conclusion, high levels of IL-6 unmask the phenotypes (higher insulin resistance and zinc deficiency) in relation to the genotypes with subsequent risk of developing ischaemic cardiomyopathy in NIDDM-atherosclerotic patients carrying AA genotype. Hence, the novel -209A/G MT2A polymorphism may be a further useful tool for the prevention, diagnosis and therapy of these combined pathologies in the elderly.

Neutrophils are the first barrier against infections. Aged neutrophils display impaired oxidative burst and phagocytosis with subsequent less capability to destroy bacteria. In successful ageing (nonagenarians), neutrophil efficiency (phagocytosis) increases. After ingested microbes, aged neutrophils are less prone to undergo apoptosis favouring chronic inflammation. Moreover, the superoxide dismutase (SOD) activity, which is necessary in avoiding ROS produced by oxidative burst, is limited in ageing. The mechanisms of age-related changes in neutrophil function are not fully understood, taking also into account that nonagenarians escape infections in comparison with elderly. Zinc pool may be involved because it is pivotal for neutrophil efficiency and SOD activity. Since zinc also controls the inflammation, via IL-6 and soluble factor of gp130 (sgp130), we have assessed the possible interrelationship among oxidative burst, apoptosis, inflammation, SOD, adhesion molecule Mac-1 and zinc pool in elderly and in nonagenarians. The oxidative burst and the capacity to increase Mac-1 after PMA stimulation decrease both in elderly and nonagenarians, but the latter display a slight increased neutrophil induced apoptosis, decreased sgp130, increased SOD, and more neutrophil zinc content, as it occurs in young-adults. Significant correlation exists between sgp130 and zinc pool in very old age. These findings suggest lower chronic inflammation in nonagenarians, via more zinc available, with subsequent long-life survival. Therefore, a more correct interrelationship among neutrophil efficiency, inflammation, antioxidant activity and zinc pool exists in successful ageing with subsequent more effectiveness to control the inflammatory response to pathogens.

The capacity of the remodeling immune responses during stress (immune plasticity) is fundamental to reach successful aging. We herein report two pivotal models to demonstrate the relevance of the immune plasticity in aging and successful aging. One model is represented by the circadian rhythms of immune responses; the other one is the immune responses during partial hepatectomy/liver regeneration (pHx). The latter is suggestive because it mimics the immunosenescence and chronic inflammation 48 hours after partial hepatectomy in the young through the continuous production of IL-6, which is the main cause of immune plasticity lack in aging. The constant production of IL-6 leads to abnormal increments of zinc-bound metallothionein (MT), which is, in turn, unable in zinc release in aging. As a consequence, low zinc ion bioavailability appears for thymic and extrathymic immune efficiency, in particular, of liver NKT cells bearing TCR gd. The remodeling during the circadian cycle and during pHx of zinc-bound MT confers the immune plasticity of liver NKT gamma delta cells and NK cells in young and very old age, not in old age. Therefore, zinc-bound MT homeostasis is crucial in conferring liver immune plasticity with subsequent successful aging.

Metallothionein (MT)-III isoform is a brain metal-binding protein that, like the MT-I + II isoform, binds zinc with high affinity. In the young-adult age, MT-III isoform increases during transient stress while MT-I + II isoform decreases, suggesting compensatory phenomena between the two isoforms and a protective role of MT-III against oxidative damage. This role may be questioned during ageing, because the stress-like condition is chronic in ageing due to high persistent levels of interleukin-6. In the present study, high expression of MT-III and MT-I + II genes (examined by RT-PCR and in situ hybridisation) was found in the hippocampus of old rats. These results indicate that a large amount of free zinc ions can be sequestered by MT isoforms, leading to impaired zinc-dependent functions in the ageing brain. In addition, zinc (tested with the Timm's method) was found to be low in mossy fibres from the old hippocampus. As this method tests bound and unbound zinc, we also investigated free zinc ion bioavailability based on the ratio active thymulin/total thymulin. We found that zinc ion bioavailability was low in old rats, together with increased interleukin-6 mRNA, high expression of both MT isoforms and reduced number of synapses whose function is zinc-dependent, in the old hippocampus. The results indicate that concomitant increments of both MT isoforms may provoke detrimental synergistic effects leading to reduced free zinc ion bioavailability for synapses. As a consequence, compensatory phenomena between MT isoforms may not occur in the old hippocampus due to chronic stress-like condition elicited by high persistent levels of interleukin-6.

Metallothioneins (MTs) play pivotal role in zinc-related cell homeostasis because of their high affinity for this trace element which is in turn relevant against oxidative stress and for the efficiency of the entire immune system, including natural killer (NK) cell activity. In order to accomplish this role, MTs sequester and/or dispense zinc during stress and inflammation to protect cells against reactive oxygen species. MTs gene expression is affected by IL-6 for a prompt immune response. Concomitantly, MTs release zinc for the activity of antioxidant zinc-dependent enzymes, including poly(ADP-ribose)polymerase-1(PARP-1), which is involved in base excision DNA-repair. This role of MTs is peculiar in young adult-age during transient stress and inflammation, but not in ageing because stress-like condition and inflammation are persistent. This may lead MTs to turn-off from role of protection in young age to deleterious one in ageing with subsequent appearance of age-related diseases (severe infections). The aim is to study the role played by MTs/IL-6/PARP-1 interplay on NK cell activity in elderly, in old infected patients (acute and remission phases by bronchopneumonia infection) and in health nonagenarian/centenarian subjects. MTmRNA is high in lymphocytes from elderly people coupled with high IL-6, low zinc ion bioavailability, decreased NK cell activity and impaired capacity of PARP-1 in base excision DNA-repair. The same trend in this altered physiological cascade during ageing also occurs in old infected patients (both acute and remission phases) with more marked immune damage, inflammatory condition and very impaired PARP-1 in base excision DNA-repair. By contrast, centenarian subjects display low MTmRNA, good zinc ion bioavailability, satisfactory NK cell activity and higher capacity of PARP-1 in base excision DNA-repair. These findings clearly demonstrate that the sequester of zinc by MTs in ageing is deleterious because leading to low zinc ion bioavailability with subsequent impairment of PARP-1 and NK cell activity and appearance of severe infections. Physiological zinc supply (12 mg Zn++/day) for 1 month in elderly and in old infected patients (remission phase) restores NK cells activity with values observed in health centenarians. Therefore, the zinc ion bioavailability by zinc-bound MTs homeostasis is pivotal to reach health longevity and successful ageing.

Advanced glycation end-products (AGEs) stimulate reactive oxygen species (ROS) generation and represent a risk factor for atherosclerosis, while their formation seems to be prevented by zinc. Metallothioneins (MT), zinc-binding proteins exert an antioxidant function by regulating intracellular zinc availability and protecting cells from ROS damages. +1245 A/G MT1A polymorphism was implicated in type 2 diabetes and in cardiovascular disease development as well as in the modulation of antioxidant response. The purpose of this study was to investigate the influence of +1245 A/G MT1A polymorphism on AGEs and ROS production and to verify the effect of zinc supplementation on plasma AGEs, zinc status parameters and antioxidant enzyme activity in relation to this SNP. One hundred and ten healthy subjects (72 ± 6 years) from the ZincAge study were supplied with zinc aspartate (10 mg/day for 7 weeks) and screened for +1245 MT1A polymorphism. +1245 MT1A G+ (Arginine) genotype showed higher plasma AGEs and ROS production in peripheral blood mononuclear cells (PBMCs) than G− (Lysine) one at the baseline. No significant changes after zinc supplementation were observed for AGEs, ROS and MT levels as well as for enzyme antioxidant activity in relation to the genotype. Among zinc status parameters, major increases were observed for the intracellular labile zinc (iZnL) and the NO-induced release of zinc in PBMCs, in G+ genotype as compared to G− one. In summary, +1245 G+ carriers showed increased plasma AGEs and ROS production in PBMCs at baseline and a higher improvement in iZnL after zinc intervention with respect to G− individuals.

Zinc is a relevant nutritional factor for the whole life of an organism because it affects the inflammatory/immune response and antioxidant activity, leading to a healthy state. Despite its important function, the dietary intake of zinc is inadequate in elderly. Possible interventions include food fortification because it does not require changes in dietary patterns, the cost is low and it can reach a large portion of the elderly population, including very old subjects. Studies evaluating the impact of Zn-fortified foods on functional parameters in elderly, in particular, in very old individuals, are missing. The objective of this study was to evaluate the efficacy of consumption of a zinc-fortified drinking skim milk (Zn-FMilk) for a period of 2 months in comparison to standard non-fortified milk (No-FMilk) on some biochemical parameters, zinc status, inflammatory/immune response and on a key parameter of the T cell-mediated immunity (thymulin hormone) in healthy very old subjects. The treatment with zinc-fortified milk (Zn-FMilk) is a good omen to increase the cell-mediated immunity in very old age represented by thymulin activity and some cytokine (IL-12p70, IFN-γ) release. At clinical level, a good healthy state occurs in 70 % of the subjects with no hospitalization after 1 year of the follow-up in comparison to very old control subjects that did not participate to crossover design. In conclusion, the Zn-FMilk can be considered a good functional food for elderly, including older people. It might be a good replacement to the zinc tablets or lozenges taking into account the attitude of old people to uptake milk as a preferential food.

Infections may cause mortality in old age due to damaged immune responses. As zinc is required as a catalyst, structural (zinc fingers) and regulatory ion, it is involved in many biological functions, including immune responses. Low zinc ion bioavailability and impaired cell-mediated immunity are common in ageing and may be restored by physiological supplementation with zinc for 1-2 months, impacting upon morbidity and survival. This article reviews the role of zinc in immune efficacy during ageing, and also describes the main biochemical pathways involved in the role of zinc in resistance to infections in ageing in order to better understand the possible causes of immunosenescence.

Nutrient “zinc” is a relevant micronutrient involved in maintaining a good integrity of many body homeostatic mechanisms, including immune efficiency, owing to its requirement for the biological activity of many enzymes, proteins, and for cellular proliferation as well as genomic stability. Old people aged 60–65 years and older have zinc intakes below 50 % of the recommended dietary allowances on a given day. Many causes can be involved: among them, impaired intestinal absorption and altered subcellular processes (zinc transporters including Zip and ZnT family, metallothioneins, divalent metal transporter 1) are the most relevant. Zinc supplementation can remodel the immune alterations in elderly leading to healthy ageing. Several zinc trials have been carried out but with contradictory data on immunity, perhaps due to incorrect choice of old subjects who effectively need zinc supplementation. Old subjects with specific metallothioneins and IL-6 polymorphisms are more prone for zinc supplementation. Foods containing zinc (Mediterranean diet) may be enough to restore immunity in other elderly. We report the main causes of low zinc dietary intake in elderly and the impact of zinc supplementation upon the inflammatory/immune response on the basis of individual interleukin-6 and metallothioneins polymorphisms (nutrigenomic approach).

Different age-related immune pathogenetic mechanisms in myasthenia gravis (MG) have been suggested because of restoration after thymectomy (Tx) of altered zinc, thymulin (TH) and T-cell subsets exclusively in early-onset patients (younger50 years), not in late-onset patients (older50 years). In this context interleukin-2 (IL-2), interleukin-6 (IL-6) and thymoma are crucial because both involved in MG pathogenesis and correlated with acetylcholine receptors (AchRs) Ab production. Moreover, IL-2 and IL-6 are zinc-dependent, are altered in aging and related with zinc and TH age-dependent declines. Moreover, zinc is relevant for immune efficiency. In order to confirm these different age-related pathogenetic mechanisms further, the role of thymoma, zinc, TH, IL-2 and IL-6 is studied in MG patients with generalized MG with and without thymoma before and 1 month and 1 year after Tx. The high IL-2, IL-6, zinc, and AChR Ab levels observed before Tx are significantly correlated each other in younger MG patients (50 years) independently by thymoma and in older MG patients (50 years) with thymoma. No correlations exist in older MG patients without thymoma. Thymulin is not correlated with other parameters considered to be both in younger and older MG patients independently by the thymoma. Thymectomy restores zinc; immune parameters and AChR Ab are exclusively in the younger group, not in the older one. These findings suggest that IL-2 and IL-6, via zinc, rather than TH, may be involved in different age-related pathogenetic mechanisms mainly in early-onset MG. By contrast, thymoma may be involved in MG etiology in late-onset representing, as such, a useful discriminant tool for MG etiology between early and late-onset MG patients. Because autoimmune phenomena may rise in aging, a parallelism with altered immune functions during aging is discussed.

Infections can cause mortality when the immune system is damaged. The catalytic, structural (in zinc-finger proteins) and regulatory roles of zinc mean that this ion is involved in the maintenance of an effective immune response. Both zinc deficiency and impaired cell-mediated immunity combine during aging to result in increased susceptibility to infection. Dietary supplementation with the recommended daily allowance of zinc for between one and two months decreases the incidence of infection and increases the survival rate following infection in the elderly. This article reviews the biochemical pathways through which zinc might act to increase immunoresistance to infection in the elderly.

Zinc is required as a catalytic, structural (zinc fingers) and regulatory ion. In this capacity, it is involved in many homeostatic mechanisms, including immune responses. Metallothioneins (MTs) may play key roles because of their preferential binding to zinc especially in ageing. MTs protect from oxidative damage during transient stress conditions at young-adult age. This protection no longer exists in ageing and in age-related diseases (cancer and infections) because the stress condition is constant. As such, MTs may constantly deplete zinc from plasma and tissues. This phenomenon causes increased MTs levels on the one hand, but on the other hand induces low zinc ion bioavailability for normal immune responses. This may be particularly relevant for thymic functions and natural killer activity. Therefore MTs which are protective in young-adults may become dangerous in immune responses during ageing. Physiological supplementation of zinc in ageing corrects central and peripheral immune defects, resulting prolonged survival and decreased mortality (50%) from infections and tumours, especially during middle age. Because of increased MT gene expression and protein levels in the liver and atrophic thymus of old mice, MTs are proposed as genetic markers of immunosenescence.

Zinc is an essential trace element for many biological functions, including immune functions. Indeed zinc is required for the biological activity of a thymic hormone, called thymulin in its zinc-bound form, important for the maturation and differentiation of T-cells. With advancing age zinc, thymic functions and peripheral immune efficiency show a progressive decline. Supplementing zinc in old age restores them. Zinc is also relevant for liver extrathymic T-cell pathway, being preeminent in old age. Since zinc is also required for metallothioneins (MTs) biological functions, binding zinc with high affinity, aim of the present article is to summarize findings from our laboratory regarding the role of zinc on T-cell pathways, investigating also the possible cause of thymic involution and impaired liver extrathymic T-cell pathway in aging. Partial hepatectomy and liver regeneration are good models for this aim because of the likeness with aging for many immune functions, including thymic functions. MTs levels are increased, other than into the liver, also into the thymus during aging and in young hepatectomized (pHx) mice as compared to young sham controls. MTs may be one of the possible causes of reduced thymic efficiency and impaired liver extrathymic T-cell pathway in old age because of their higher zinc binding affinity rather than thymulin with consequent reduction of the free quota of zinc available for normal cell-mediated immunity. Following that, MTs may contribute to thymic involution and impaired peripheral immune efficiency in aging and in young pHx mice with different roles during the whole life of an organism: protective in young-adult age which may became, at least, dangerous for immune responses in aging. In order to limit or avoid this latter MTs possible role in aging, supplementing physiological zinc may be useful to improve immune responses in old age because of no interference of endogenous zinc on already high thymus MTs levels, but with caution for competition phenomena with copper, as documented in old mice and in syndrome of accelerate aging.

The role of metallothioneins (MTs) in aging is not completely understood. Several studies have shown evidence that these proteins could represent a defense system against oxidative damage, but survival studies on mice overexpressing MTs are poor. Here we describe a survival study performed on old MT-1-overexpressing mice (MT-TG) and their respective controls (C57BL/6J) fed a standard or zinc (Zn)-supplemented diet. MT-TG mice had significantly increased survival compared with control. Zn supplementation affects the survival curves of MT-TG and C57BL/6J mice differently. This study poses the basis for intervention based on gene therapy with MTs to enhance the health span of laboratory mice.

In ageing, alterations in inflammatory/immune response and antioxidant capacity lead to increased susceptibility to diseases and loss of mobility and agility. Various essential micronutrients in the diet are involved in age-altered biological functions. Micronutrients (zinc, copper, iron) play a pivotal role either in maintaining and reinforcing the immune and antioxidant performances or in affecting the complex network of genes (nutrigenomic approach) involved in encoding proteins for a correct inflammatory/immune response. By the other side, the genetic inter-individual variability may affect the absorption and uptake of the micronutrients (nutrigenetic approach) with subsequent altered effects on inflammatory/immune response and antioxidant activity. Therefore, the individual micronutrient-gene interactions are fundamental to achieve healthy ageing. In this review, we report and discuss the role of micronutrients (Zn, Cu, Fe)-gene interactions in relation to the inflammatory status and the possibility of a supplement in the event of a micronutrient deficiency or chelation in presence of micronutrient overload in relation to specific polymorphisms of inflammatory proteins or proteins related of the delivery of the micronutriemts to various organs and tissues. In this last context, we report the protein-metal speciation analysis in order to have, coupled with micronutrient-gene interactions, a more complete picture of the individual need in micronutrient supplementation or chelation to achieve healthy ageing and longevity.

The diet in the elderly does not provide a sufficient level of nutrients needed to maintain an adequate healthy status leading to micronutrient deficiencies and impaired immune response with subsequent development of degenerative diseases. Nutrient >zinc> is a relevant micronutrient involved in maintaining a good integrity of many body homeostatic mechanisms, including immune efficiency, owing to its requirement for the biological activity of many enzymes, proteins and for cellular proliferation and genomic stability. Old people aged 60-65 years and older have zinc intakes below 50% of the recommended daily allowance on a given day. Many causes can be involved: among them, altered intestinal absorption, inadequate mastication, psychosocial factors, drugs interactions, altered subcellular processes (zinc transporters (Zip and ZnT family), metallothioneins, divalent metal transporter-1). Zinc supplementation may remodel the immune alterations in elderly leading to healthy ageing. Several zinc trials have been carried out with contradictory data, perhaps due to incorrect choice of an effective zinc supplementation in old subjects showing subsequent zinc toxic effects on immunity. Old subjects with specific IL-6 polymorphism (GG allele carriers; named C-) are more prone for zinc supplementation than the entire old population, in whom correct dietary habits with foods containing zinc (Mediterranean diet) may be sufficient in restoring zinc deficiency and impaired immune response. We summarise the main causes of low zinc dietary intake in elderly reporting an update on the impact of zinc supplementation upon the immune response also on the basis of individual IL-6 polymorphism.

Intracellular zinc homeostasis is crucial in regulating the inflammatory/immune response at any age. It is tightly regulated by zinc transporters that control influx, efflux and compartmentalization of zinc within the cells. Specific methods for detecting the age-related differences in intracellular zinc signaling are poorly described. We report a novel assay induced after the in vitro zinc addition in peripheral blood mononuclear cells (PBMCs) and in lymphocytes from young and old donors in the absence/presence of in vitro zinc depletion (using EDTA). The intracellular labile zinc variations are monitored over time by flow cytometry using Fluozin-3 AM probe. The best curve fit of the data is calculated using a nonlinear regression model defined as follows: pr3/[1+Exp(−pr1−pr2⁎Xt)]. Pr1 depends on the initial free zinc value (time 0); pr2 describes the rate of the speed in reaching the maximum intracellular free zinc concentration; pr3 represents the maximum intracellular zinc increment (plateau curve); Xt is the time course. Age-related intracellular free zinc variations occur in PBMCs and lymphocytes incubated in EDTA-supplemented medium. The higher plateau of the curve (pr3) was observed in younger subjects. An up-regulation of Zip genes (Zip1, Zip2, Zip3), influencing zinc influx, is more pronounced in the young than old donors. Interleukin-6 and tumor necrosis factor-α overproduction was enhanced in old individuals, suggesting the presence of more marked zinc deficiency and chronic inflammation. In conclusion, the determination of intracellular zinc signals induced by in vitro zinc addition using logistic parameters may be useful to estimate the rate of intracellular zinc homeostasis and its role in inflammatory/immune response in aging.

International audience; Although zinc plays an important role in health status of the elderly, their dietary habits in relation to zinc intake are not well documented. The main objective of the current study was the assessment of dietary zinc intake in European old populations and the investigation of its impact on plasma zinc and inflammatory cytokines concentrations, in relation to genetic markers. Within the ZINCAGE study, 819 healthy old Europeans (>/=60 years old) were recruited. Plasma zinc, interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured. Genotype data were obtained for the -174G/C polymorphism in the IL-6 gene. Dietary data were collected with a food frequency questionnaire and were used to calculate a zinc diet score. Zinc score was validated using additional dietary data (24-h recalls), in a subsample of 105 subjects. Zinc score was different among most of the European centres (P

Ageing is an inevitable biological process with gradual and spontaneous biochemical and physiological changes and increased susceptibility to diseases. Some nutritional factors (zinc, niacin, selenium) may remodel these changes leading to a possible escaping of diseases, with the consequence of healthy ageing, because they are involved in improving immune functions, metabolic homeostasis and antioxidant defence. Experiments performed "in vitro" (human lymphocytes exposed to endotoxins) and "in vivo" (old mice or young mice with low zinc dietary intake) show that zinc is important for immune efficiency (both innate and adaptive), metabolic homeostasis (energy utilization and hormone turnover) and antioxidant activity (SOD enzyme). Niacin is a precursor of NAD+, the substrate for the activity of DNA repair enzyme PARP-1 and, consequently, may contribute to maintaining genomic stability. Selenium provokes zinc release by Metallothioneins (MT), via reduction of glutathione peroxidase. This fact is crucial in ageing because high MT may be unable to release zinc with subsequent low intracellular free zinc ion availability for immune efficiency, metabolic harmony and antioxidant activity. Taking into account the existence of zinc transporters (ZnT and ZIP family) for cellular zinc efflux and influx, respectively, the association between zinc transporters and MT is crucial in maintaining satisfactory intracellular zinc homeostasis in ageing. Improved immune performance, metabolic homeostasis, antioxidant defence occur in elderly after physiological zinc supplementation, which also induces prolonged survival in old, nude and neonatal thymectomized mice. The association "zinc plus selenium" improves humoral immunity in old subjects after influenza vaccination. The association "zinc plus niacin" in elderly is actually in progress.

It is known that metallothionein (MT) mRNA expression first increases with age, but then decreases again in the very elderly. Here we report that MT protein levels also decrease in very old age, and that this is independent of dietary zinc intake. Age-related changes of MT, as well as alterations of zinc homeostasis (intracellular labile zinc and NO-induced zinc release), occur both in human PBMCs ex vivo and also in CD4+ T cell clones progressing through their finite life span in vitro. These results suggest that phenomena observed in very old people can be at least partially attributed to diminished cell proliferation.

Taking into account the antioxidant properties of zinc, it is difficult to explain the beneficial effects of HMG-CoA reductase inhibitors in the context of a well-known decreased zinc status. Therefore, intracellular zinc homeostasis was studied in patients with low-grade carotid atherosclerosis under treatment with HMG-CoA reductase inhibitors using a custom microarray-based approach developed by pooling information across microarray studies. Experimental data unravel an active zinc signaling in PBMC from low-grade atherosclerotic patients under lipid reduction therapy, suggesting that monitoring intracellular zinc status could be a key factor for an optimal strategy and targeting a level of intervention.

Zinc is relevant for psychological dimensions, which are altered in zinc deficiency, as in aging. Since zinc deficiency and the beneficial effect of zinc supplementation may be related to genotypes of IL-6 -174 polymorphism, the main goal was to examine psychological dimensions in relationship to plasma zinc and genetic background of IL-6 in healthy elderly subjects, recruited in Italy, Greece, and Poland, before and after zinc supplementation. On the basis of IL-6 -174 polymorphism, significant restoration occurs for PSS, especially in Greece and Poland, less for MMSE and GDS, after zinc supplementation, suggesting zinc is important in reducing stress in elderly people.