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.

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IL-6 SNP at position -174 is associated with age-related diseases characterized by an impaired Zn status. This polymorphism seems also relevant in regulating the expression of proteins, such as Metallothioneins (MT), involved in the modulation of Zn homeostasis. Since high IL-6 levels in elderly induce hypozinchemia, the IL-6-174 SNP may be useful to identify old subjects who are at risk for Zn deficiency. The objectives of this study are: (1) to choose old subjects who effectively need Zn supplementation and (2) to study the effect of Zn supplementation on Zn, immune and psychological status in genetically selected subjects. For this purpose, a baseline study comprising 895 healthy old subjects recruited in Central-Northern and Southern European Countries was carried out by evaluating their dietary intake, psychological and immune parameters as well as their Zn status. A Zn supplementation trial was performed in 110 old subjects selected on the basis of their plasma Zn levels and IL-6 SNP. After correcting for age and Zn intake, C- carriers displayed higher MT and lower levels of several parameters related to zinc status (plasma Zn, erythrocyte Zn and NO-induced release of Zn in PBMC) than C+ carriers. Better NK cell cytotoxicity and psychological functions (PSS, MMSE) were also found in C+ than C- carriers strictly related to the zinc status. However, independently by the polymorphism, all subjects with plasma zinc < or = 10.5microM showed the worst immune response and psychological functions. Supplementation was carried out in C+ and C- carriers with stable low plasma zinc levels ( < or =10.5microM at baseline and at 1 year follow-up) and in C- carriers with unstable plasma zinc (< or =10.5microM at baseline and >10.5microM at 1 year follow-up). C+ carriers with plasma zinc >10.5microM were not supplemented because showing the best immune and psychological conditions. After 48+/-2 days of supplementation with 10mg/day of Zn-aspartate, the NO-induced release of Zn, erythrocyte Zn and NK cell cytotoxicity increased in all groups selected for supplementation, including C- with unstable plasma zinc. In conclusion, the sole assessment of plasma Zn level is not reliable to exclude C- carriers from Zn supplementation. A possible explanation for the conflicting data on the identification of IL-6-174G as a "risk allele" based on different dietary intake in the studied population is also suggested.

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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.

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Background: The amount of available intracellular zinc is pivotal to regulate many cellular processes, including oxidative stress response and apoptotic mechanisms. Therefore it is not surprising that zinc homeostasis and dyshomeostasis is involved in many physiological and pathological states, respectively. Cell permeable zinc probes allow intracellular applications with microscopy technology, but flow cytometry (FC) applications have been scarcely explored, albeit they can be suited to study zinc homeostasis in different cell types, including rare cells. Methods: We describe a FC method able to estimate intracellular zinc ion availability and the intracellular capability to activate a zinc signal after treatment with an NOdonor (AcOM-DEA/NO) in human PBMCs, using the fluorescent zinc-specific probe, Zinpyr-1 (ZP1), alone or in association with CD4-PE and CD8-Cychrome mAb.