Gene Expression, Oxidative Stress, and Senescence of Primary Coronary Endothelial Cells Exposed to Postprandial Serum of Healthy Adult and Elderly Volunteers after Oven-Cooked Meat Meals.

Epidemiological studies have linked high consumption of meat with major age-related diseases including cardiovascular diseases. Abnormal postprandial increases in plasma lipids after a meat meal have been hypothesized among the pathogenetic mechanisms. However, it is still unknown if the postprandial serum derived after a normal meat meal is able to affect endothelial function, and if the type of meat and the age of the donors are critical factors. Here, we show the effects of postprandial sera derived from healthy adults and elderly volunteers who consumed meat meals on human coronary artery endothelial cell (HCAEC) oxidative stress, gene expression, DNA damage, and cellular senescence. We observed that a single exposure to postprandial serum induces a slight increase in ROS that is associated with modulation of gene expression pathways related to oxidative stress response and metabolism. The postprandial-induced increase in ROS is not associated with a measurable DNA oxidative damage. However, repeated exposure to postprandial serum induces an acceleration of cellular senescence. Taking into account the deleterious role of cellular senescence in age-related vascular diseases, the results suggest a new mechanism by which excessive meat consumption and time spent in postprandial state may affect health status during aging.

Correlates of perceived health related quality of life in obese, overweight and normal weight older adults: an observational study.

BACKGROUND: Obesity is a complex multifactorial disease, which also has an impact on quality of life. The aim of this paper is to identify the correlates of perceived health related quality of life in obese, overweight and normal weight Italians older adults. METHODS: 205 subjects at the age ≥ 60 yrs. were recruited into the Division of Endocrinology of the Polytechnic University of Marche Region, Ancona (Italy). A protocol of questionnaires was constructed for data collection, and included domains such as physical activity, quality of life, socio-psychological aspects. The association of the latter variables with SF-36 Health Survey physical component (PCS-36) were evaluated in the whole sample. Multiple linear regression models were used to assess the effect of independent variables on PCS-36 and the physical subscales of SF-36. RESULTS: PCS-36 showed a lower score in the obese and overweight subjects than the normal weight group (post-hoc test, p < 0.001 and p < 0.05 respectively). Age, gender (male), Body Mass Index, years of education, Physical Activity Scale for the Elderly (PASE) total score, Hospital Anxiety and Depression Scale anxiety, Hospital Anxiety and Depression Scale depression, number of medications prescribed and number of diseases were included in the model. Negative and significant PCS-associated variables included depression (p = 0.009), BMI (p = 0.001), age in years (p = 0.007), whereas positive and significant PCS-associated independent variables were years of education (p = 0.022), physical activity (p = 0.026). BMI was negatively associated with all the physical subscales of SF-36 (p < 0.05). CONCLUSIONS: Research funding should be invested in the study of the benefits accruing from reducing obesity in the elderly.

Effects of human Toll-like receptor 1 polymorphisms on ageing.

BACKGROUND: Advanced age results in crucial alterations of the innate and adaptive immune system leading to functional defects resulting in infection and chronic diseases. Toll-like receptors (TLR) recognize pathogenic structures and are important in the immune response to infections and vaccination. However, the role of TLR single nucleotide polymorphisms (SNP) is poorly understood in the setting of human ageing. This study investigated the impact of the TLR1 SNPs A743G and T1805G on ageing in different age groups from two European populations. RESULTS: The TLR1 genotypes 743AA/1805GG (TLR1neg) are associated with a TLR1 negative phenotype, impaired function and susceptibility to tuberculosis. Carriers of heterozygous 743AG/1805TG and homozygous 743GG/1805TT genotypes (TLR1pos) have a TLR1 positive phenotype. By comparing healthy young and old German donors, the old group showed a tendency to carry more TLR1neg and less homozygous TLR1pos genotypes. Anti-inflammatory Interleukin (IL)-1 receptor antagonist (Ra) was significantly elevated in supernatants of mononuclear cells from old German subjects with a TLR1pos genotype in contrast to those with the 743AA genotype. Healthy old individuals and nonagenarians from Italy displayed significantly higher frequencies of TLR1pos genotypes than the old group from Germany. The data show that tumor-necrosis-factor (TNF)α, CXCL8 and CCL2 levels were higher in old donors from Germany than in plasma levels from old Italian donors. TNFα and CCL2 levels were significantly raised in old German individuals compared to Italian nonagenarians. German and Italian donors with the TLR1neg genotype basically produced more CCL2 than older European donors with TLR1pos genotypes. CONCLUSION: The higher frequency of the TLR1pos genotype in elderly Italian subjects may result from different ethnic populations. Lower inflammatory mediator release of aged Italian individuals is probably due to different background in nutrition, diet, genetics and to psychological aspects. Elderly donors carrying TLR1pos genotypes basically release more anti-inflammatory IL-1Ra and less inflammatory CCL2 suggesting a decline of the pro-inflammatory status found in ageing and, therefore, this may define an anti-inflammatory phenotype. Future studies are needed to elucidate the association of a TLRpos genotype with decreased susceptibility to infections and reduced risk to develop artherosclerosis.

Speciation of trace elements in human serum by micro anion exchange chromatography coupled with inductively coupled plasma mass spectrometry.

Speciation analysis of essential trace elements in human serum provides important information on nutritional status and homeostatic mechanisms regulating transport processes, acute phase reactions, and protection against oxidative damage. Anion exchange high-performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectrometry (ICP-MS) has proved to be a useful tool in speciation. Here we describe a fast method that can be applied to carry out the speciation of Fe, Cu, Zn, and Se in as little as 1 microl [corrected] of serum. The method employs monolithic anion exchange micro columns installed on a tandem HPLC system coupled on-line with an ICP-MS detector. The chromatographic separation is similar to those reported previously but with considerable gain in terms of time and sample requirement. Reproducibility is acceptable for most species. Using our method, we were able to find species-specific differences between different commercially available trace element reference materials. Because the method chosen to collect blood might interfere with speciation, the proposed methodology was used to compare heparinized plasma, ethylenediaminetetraacetic acid (EDTA) plasma, and serum from adult healthy volunteers. As expected, EDTA strongly affects speciation analysis (especially for Fe and Zn), whereas changes due to the use of lithium-heparin (Li-He) as anticoagulant appear to be minimized.

Metalloproteases/anti-metalloproteases imbalance in chronic obstructive pulmonary disease: genetic factors and treatment implications.

PURPOSE OF REVIEW: The aim is to describe the involvement of matrix metalloprotease (MMP), A Disintegrin And Metalloproteases (ADAM), tissue inhibitors of MMP (TIMP) polymorphisms and the role of α-2 Macroglobulin (α-2M) in chronic obstructive pulmonary disease (COPD) development and progression, with a focus on interventions with synthetic MMP inhibitors alone or associated with current drugs used in COPD therapy in order to restore MMPs/TIMPs imbalance. RECENT FINDINGS: COPD is one of the major causes of death in the elderly. It is characterized by progressive development of airflow limitation manifested by decreased forced expiratory volume in one second (FEV1) and reduction in the percentage of FEV1/forced vital capacity. The major pathogenic role is played by metalloproteases (MMPs, ADAMs)/anti-metalloproteases (TIMPs, α-2M) imbalance, which is responsible for MMP overproduction not sufficiently counteracted by TIMPs or α-2M. As a consequence, the lung extracellular matrix is destroyed with obstruction of small airways and appearance of emphysema. SUMMARY: The disease is mainly caused by exposure to cigarette smoke or noxious gases and air pollutants, but also genetic factors are involved. Among them, polymorphisms of MMPs (MMP1, MMP2, MMP9, MMP12), ADAMs (ADAM33) and TIMPs (TIMP1, TIMP2) are relevant, in which the inflammation and the smoking habit play key roles especially in unfavorable allele carriers. The association between these polymorphisms and the current drugs paves the way for personalized therapy with a great impact at clinical level.

Zinc, metallothioneins and immunosenescence: effect of zinc supply as nutrigenomic approach.

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.

Age, Sex, and BMI Influence on Copper, Zinc, and Their Major Serum Carrier Proteins in a Large European Population Including Nonagenarian Offspring From MARK-AGE Study.

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.

Diet (zinc)-gene interaction related to inflammatory/immune response in ageing: possible link with frailty syndrome?

The pivotal role played by zinc-gene interaction in affecting the inflammatory response mediated by IL-6 in ageing, successful ageing (nonagenarians) and the most common age-related diseases is now recognized. Contradictory data emerging from association studies of IL-6 polymorphisms with longevity and chronic age-related diseases seem to arise from the interaction of this inflammatory pathway with dietary habits. Similar conclusions are expected to arise from association studies with the frailty syndrome. Some polymorphisms of genes related to vitamin B12 availability have been already found to be associated with frailty suggesting a possible link among diet-gene interaction and frailty in old age. Other studies in this field are urgently required because of their high potential for suggesting strategies in the care and prevention of frailty in ageing through dietary interventions, in which nutrient zinc may play a pivotal role taking into account that the high copper to zinc ratio is a significant index of the mortality in older people.

Plasma copper/zinc ratio: an inflammatory/nutritional biomarker as predictor of all-cause mortality in elderly population.

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.

In vivo effect of alpha-bisabolol, a nontoxic sesquiterpene alcohol, on the induction of spontaneous mammary tumors in HER-2/neu transgenic mice.

Breast cancer represents the most commonly diagnosed invasive malignancy in pre- and postmenopausal women in both developed and underdeveloped countries. Taking into account that treatment options, including surgery, have not been able to deal with the growing incidence of breast malignancy, it is required to develop mechanism-based novel agents for its prevention. Wide interest in some natural compounds as antiinflammatory agents and as alternative to the traditional medicines is increasing because they do not provoke any adverse effects and are effective in multiple organs, alpha-Bisabolol (BISA), a small oily sesquiterpene alcohol, was reported as chemopreventive agent in induced rat mammary carcinogenesis. The aim of the present study is to investigate the role played by two doses of BISA (via intramammary infusion) on the induction and development of mammary tumor in HER-2/neu transgenic mice as well as the BISA effect after tumor surgical resection. The main data show that (a) optimal dosage of BISA is 10 mg/mouse rather than 3.6 mg/mouse with no adverse effects (e.g., alopecia); (b) the number of the palpable tumor masses decreases in mice treated with 10 mg/mouse of BISA; (c) mice after surgical resection of the primary tumor and treatment with BISA (10 mg) are free from tumor for more weeks, after the surgical treatment; (d) using array analysis, some genes implicated in carcinogenesis mechanisms (NF-kappaBia, Map2k, Mapkl4, and HER2/ neu), angiogenesis process (Fgf), and inhibition of apoptosis (Birc5) are differently regulated after BISA treatment, with a downregulation of the HER2/neu as well as of Fgf and Birc5 genes; (e) the NK cell cytotoxicity increases in tumor-treated mice, especially after the removal of the first tumor mass. Such effectiveness could be important to achieve goals for a possible combination of BISA to conventional therapies in breast cancer and to tumor surgical removal (adjuvant therapy), as suggested for other sesquiterpene analogs.

Prevalence and Loads of Torquetenovirus in the European MARK-AGE Study Population.

Torquetenovirus (TTV) viremia has been associated with increased mortality risk in the elderly population. This work aims to investigate TTV viremia as a potential biomarker of immunosenescence. We compared levels of circulating TTV in 1813 participants of the MARK-AGE project, including human models of delayed (offspring of centenarians [GO]) and premature (Down syndrome [DS]) immunosenescence. The TTV load was positively associated with age, cytomegalovirus (CMV) antibody levels, and the Cu/Zn ratio and negatively associated with platelets, total cholesterol, and total IgM. TTV viremia was highest in DS and lowest in GO, with intermediate levels in the SGO (spouses of GO) and RASIG (Randomly Recruited Age-Stratified Individuals From The General Population) populations. In the RASIG population, TTV DNA loads showed a slight negative association with CD3+T-cells and CD4+T-cells. Finally, males with ≥4log TTV copies/mL had a higher risk of having a CD4/CD8 ratio<1 than those with lower viremia (odds ratio [OR] = 2.85, 95% confidence interval [CI]: 1.06-7.62), as well as reduced CD3+ and CD4+T-cells compared to males with lower replication rates (<4log), even after adjusting for CMV infection. In summary, differences in immune system preservation are reflected in the models of delayed and premature immunosenescence, displaying the best and worst control over TTV replication, respectively. In the general population, TTV loads were negatively associated with CD4+ cell counts, with an increased predisposition for an inverted CD4/CD8 ratio for individuals with TTV loads ≥4log copies/mL, thus promoting an immune risk phenotype.

NK and NKT cells in aging and longevity: role of zinc and metallothioneins.

INTRODUCTION: 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. DISCUSSION: 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.

Zinc signalling and subcellular distribution: emerging targets in type 2 diabetes.

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.

Inflammation, genes and zinc in Alzheimer's disease.

Alzheimer's disease (AD) is a heterogeneous and progressive neurodegenerative disease which in Western society mainly accounts for clinical dementia. AD has been linked to inflammation and metal biological pathway. Neuro-pathological hallmarks are senile plaques, resulting from the accumulation of several proteins and an inflammatory reaction around deposits of amyloid, a fibrillar protein, Abeta, product of cleavage of a much larger protein, the beta-amyloid precursor protein (APP) and neurofibrillary tangles. Amyloid deposition, due to the accumulation of Abeta peptide, is the main pathogenetic mechanism. Inflammation clearly occurs in pathologically vulnerable regions of AD and several inflammatory factors influencing AD development, i.e. environmental factors (pro-inflammatory phenotype) and/or genetic factors (pro-inflammatory genotype) have been described. At the biochemical level metals such as zinc are known to accelerate the aggregation of the amyloid peptide and play a role in the control of inflammatory responses. In particular, zinc availability may regulate mRNA cytokine expression, so influencing inflammatory network phenotypic expression.

Combination of biomarkers to predict mortality in elderly patients with myocardial infarction.

OBJECTIVE: The elderly subjects affected by Acute Myocardial Infarction (AMI) have the highest risk of mortality. Our study was designed to improve the capability of mortality risk stratification in elderly AMI patients through the concurrent evaluations of different biomarkers, including genetic markers. METHODS AND RESULTS: One-year follow-up study was performed in 250 elderly AMI patients. The combination of high total Homocysteine (tHcy), low folate and vitamin B12 plasma levels (18.0+/-9.0 micromol/l; 4.4+/-1.2 ng/ml; 404.2+/-287.5 pg/ml, respectively) and elevated CRP plasma levels (> or =6 mg/dl) identify the highest-risk pathway of heart mortality (RR=4.20, IC 95% 1.62-10.89, P<0.002) with respect to the combination of low total tHcy, high folate and vitamin B12 plasma levels (12.4+/-5.2 micromol/l; 8.9+/-2.5 ng/ml; 546.9+/-379.8 pg/ml, respectively) and low CRP plasma levels (<6 mg/dl). CONCLUSION: In elderly AMI patients the concomitant elevation of CRP and tHcy, associated with folate and vitamin B12 low levels, could be considered a significant predictive heart mortality risk factor.

Zinc supplementation boosts the stress response in the elderly: Hsp70 status is linked to zinc availability in peripheral lymphocytes.

Chaperones and zinc are indispensable for proper immune function. All the zinc status, the immune function and the stress response decline during aging. Here we studied the effect of nutritional zinc and zinc homeostasis on the stress response in healthy old subjects recruited during the ZincAge European Union project that either underwent or not a 48-day zinc supplementation. Inducible Hsp70 levels were determined at basal conditions as well as after heat shock in the CD3+ and CD3- subset of lymphocytes by a two-color FACS analysis. Short term zinc supplementation resulted in a marked increase in both basal as well as stress-induced Hsp70 levels in lymphocytes from healthy elderly donors with a higher impact on CD3+ cells. Heat inducibility showed a strong correlation with basal Hsp70 level, and both basal as well as stress-induced Hsp70 highly correlated with intracellular zinc availability. In conclusion, short term oral supplementation with zinc safely and efficiently induces the stress response in lymphocytes of old donors. The stress response may be a candidate pathway connecting zinc deficiency with aging and immunosenescence. Thus, proper dietary zinc intake may emerge as a chaperone inducer and an anti-aging mechanism in the immune system.

Effect of zinc on cellular poly(ADP-ribosyl)ation capacity.

Poly(ADP-ribosyl)ation is a posttranslational protein modification, which is catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1) and plays a role in DNA repair and maintenance of genomic stability. A decrease in cellular poly(ADP-ribosyl)ation has been implicated in the aging process. As PARP-1 is a zinc finger protein its decreased function might be related to age-related zinc deficiency. To test this hypothesis we assessed cellular poly(ADP-ribosyl)ation capacity in 29 donors from Greece, Italy and Poland as function of age and nutritional zinc status. Our results reveal a positive correlation between cellular poly(ADP-ribosyl)ation capacity and zinc status in human peripheral blood mononuclear cells (PBMC) (p<0.05). We could also confirm a decrease of PARP-1 activity with donor age, highlighting the role of poly(ADP-ribosyl)ation in the aging process. The results demonstrate that zinc supplementation in elderly people can increase the cellular poly(ADP-ribosyl)ation capacity of their PBMC. We speculate that this may help maintain integrity and stability of the genome more efficiently and thus contribute to an extension of healthspan.

Zinc supplementation in the elderly subjects: effect on oxidized protein degradation and repair systems in peripheral blood lymphocytes.

Aging has been associated with zinc deficiency, leading to chronic inflammation and subsequent oxidative stress, especially in the immune system. The increased oxidative stress provokes the accumulation of oxidized proteins, raising the problem of the efficacy of intracellular protein maintenance systems responsible for the elimination of oxidatively modified proteins. Our objective was to analyse the effect of zinc supplementation in the elderly on protein maintenance in peripheral blood lymphocytes. The status of the proteasome, which is in charge of oxidized protein degradation and the repair enzymes peptide methionine sulfoxide reductases, which can reverse methionine oxidation in proteins, were analysed on peripheral blood lymphocytes collected from 20 elderly subjects (age range between 59 and 85 years old) before and after zinc supplementation (10mg of zinc per day for 48+/-2 days). A decrease of oxidized protein content in zinc supplemented subjects was observed and was associated with an increase of expression levels and/or activities of proteasome and methionine sulfoxide reductases. Our results indicate that zinc treatment could enhance the anti-oxidative defences of peripheral blood lymphocytes by increasing the activities of protein maintenance systems responsible for the elimination of oxidatively modified proteins.

TH1 and TH2 cell polarization increases with aging and is modulated by zinc supplementation.

Elderly subjects suffer from increased levels of activated T cells and a TH1/TH2 imbalance. Zinc deficiency of the aged is correlated with decreased cell-mediated immune responses. The association of age and zinc adjustment with the amounts of TH1 (CCR5+) and TH2 (CCR4+) cell populations in healthy aged old donors enrolled in the European ZINCAGE project was examined. Old and nonagenarian individuals revealed increased TH1, TH2 cell numbers and a decreased TH2/TH1 ratio in comparison to young individuals. The differences between TH2/TH1 ratios of young and old/nonagenarians arose from young females. Adjusted zinc status led to enhanced TH2 and TH1 amounts in fresh whole blood and thawed cells of aged donors whereas increased HLA-DR+ expression and a generally lower CCR5 expression was observed on thawed PBMC. In conclusion, aging is associated with an increase in T helper cell polarization, and changes in TH2/TH1 subsets are more obvious in women than in men. Advanced healthy aging is accompanied by TH cell polarization, too. Moderate zinc supplementation in vivo alters TH proportions. Longer zinc treatment will give more insight into the beneficial effect of zinc on T helper cell modulation.

In vitro and in vivo effects of zinc on cytokine signalling in human T cells.

Aging is associated with changes in the immune response which are collectively called immunosenescence. The changes mainly affect the adaptive immune response and especially the T cell-mediated cellular immune response. There are a few data indicating that the cytokine signalling in T cells is altered with aging. Zinc has been specifically shown to have potent immunomodulatory effects. The aim of the present work was to study the IL-2 and IL-6 cytokine signalling and activation induced cell death (AICD) in T cells of elderly subjects of various ages and from various European countries. These experiments were performed in the frame of European Community financed project called ZINCAGE "Nutritional zinc, oxidative stress and immunosenescence: biochemical, genetic and lifestyle implications for healthy ageing", assembling 17 laboratories from 8 countries through Europe. The study was carried out in a total of 312 French and a group of 201 (26 from Italy, 63 from France, 57 from Greece, 24 from Poland and 30 from Germany) healthy non-institutionalized men and women older than 60 years of age, with available dietary data. Human peripheral blood mononuclear cells (PBMC) were obtained from heparinized blood and were stimulated in vitro by IL-2 or IL-6 for various periods and the phosphorylation of STAT3 and STAT5 was measured by FACScan. The activation induced cell death (AICD) was measured after anti-CD3 and CD28 restimulation for 48h by using the Annexin:FITC Apoptosis Kit. We found that there is an IL-2 signalling defect with aging up to 90 years of age which cannot be modulated by zinc. In contrast at 90 years and over the zinc could reverse the negative signalling effect of IL-2. There is also a signalling defect for STAT3 and STAT5 activation in T cells under IL-6 stimulation with aging and the zinc supplementation could potentiate only the STAT5 activation in the age-group 90 years and over. Studying signalling in PBL from different countries we detected less activation in T cells of subjects from France and the most changes occurred in T cells of subjects from Poland, suggesting no correlation with the plasma zinc status observed in these countries. In vivo zinc supplementation had no effect on IL-2 and IL-6-modulated STAT3 and STAT5 activation. Zinc added in vitro to these T cells even inhibited the stimulation either by IL-2 or by IL-6. Zinc supplementation improved the susceptibility of T cells to AICD in both age-groups, with more efficiency in later ages. Our results suggest that zinc can have a potent immunomodulatory effect via the modulation of cytokine signalling and AICD, however this effect depends on the function and the activation status of the T cells.