Effect of ZIP2 Gln/Arg/Leu (rs2234632) polymorphism on zinc homeostasis and inflammatory response following zinc supplementation.

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.

Effects of zinc-fortified drinking skim milk (as functional food) on cytokine release and thymic hormone activity in very old persons: a pilot study.

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.

One-month strawberry-rich anthocyanin supplementation ameliorates cardiovascular risk, oxidative stress markers and platelet activation in humans.

Strawberries are an important fruit in the Mediterranean diet because of their high content of essential nutrients and beneficial phytochemicals, which seem to exert beneficial effects in human health. Healthy volunteers were supplemented daily with 500 g of strawberries for 1 month. Plasma lipid profile, circulating and cellular markers of antioxidant status, oxidative stress and platelet function were evaluated at baseline, after 30 days of strawberry consumption and 15 days after the end of the study. A high concentration of vitamin C and anthocyanins was found in the fruits. Strawberry consumption beneficially influenced the lipid profile by significantly reducing total cholesterol, low-density lipoprotein cholesterol and triglycerides levels (-8.78%, -13.72% and -20.80%, respectively; P<.05) compared with baseline period, while high-density lipoprotein cholesterol remained unchanged. Strawberry supplementation also significant decreased serum malondialdehyde, urinary 8-OHdG and isoprostanes levels (-31.40%, -29.67%, -27.90%, respectively; P<.05). All the parameters returned to baseline values after the washout period. A significant increase in plasma total antioxidant capacity measured by both ferric reducing ability of plasma and oxygen radical absorbance capacity assays and vitamin C levels (+24.97%, +41.18%, +41.36%, respectively; P<.05) was observed after strawberry consumption. Moreover, the spontaneous and oxidative hemolysis were significant reduced (-31.7% and -39.03%, respectively; P<.05), compared to the baseline point, which remained stable after the washout period. Finally, strawberry intake significant decrease (P<.05) the number of activated platelets, compared to both baseline and washout values. Strawberries consumption improves plasma lipids profile, biomarkers of antioxidant status, antihemolytic defenses and platelet function in healthy subjects, encouraging further evaluation on a population with higher cardiovascular disease risk.

Comparison of intracellular zinc signals in nonadherent lymphocytes from young-adult and elderly donors: role of zinc transporters (Zip family) and proinflammatory cytokines.

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.

Strawberry consumption improves plasma antioxidant status and erythrocyte resistance to oxidative haemolysis in humans.

Significant increases in the plasma total antioxidant capacity (TAC) have already been reported after acute intake of strawberries. In addition, antihaemolitic effects of strawberry extracts have been recently demonstrated in vitro, revealing that part of the antioxidant properties of strawberry bioactive compounds could lie in their localisation within cell membranes. However, there is a lack of research evidence from in vivo protracted strawberry consumption studies. We carried out a 16-day pilot study where 12 healthy subjects ingested 500g of antioxidants-rich strawberries daily, and we evaluated the potential effects of fruit consumption on biomarkers of plasma and cellular antioxidant status. A significant increase in fasting plasma TAC and in serum vitamin C concentrations were progressively observed during the period of strawberry supplementation. An enhanced resistance to haemolysis was also observed in both AAPH-treated and untreated erythrocytes, collected during and after the period of strawberry consumption. The results obtained in this work suggest that regular consumption of antioxidant-rich strawberries may exert an improvement on the plasma antioxidant status and an increase on the antihaemolitic defenses of human erythrocytes.