The oxidative hypothesis of senescence, since its origin in 1956, has garnered significant evidence and growing support among scientists for the notion that free radicals play an important role in ageing, either as "damaging" molecules or as signaling molecules. Age-increasing oxidative injuries induced by free radicals, higher susceptibility to oxidative stress in short-lived organisms, genetic manipulations that alter both oxidative resistance and longevity and the anti-ageing effect of caloric restriction and intermittent fasting are a few examples of accepted scientific facts that support the oxidative theory of senescence. Though not completely understood due to the complex "network" of redox regulatory systems, the implication of oxidative stress in the ageing process is now well documented. Moreover, it is compatible with other current ageing theories (e.g., those implicating the mitochondrial damage/mitochondrial-lysosomal axis, stress-induced premature senescence, biological "garbage" accumulation, etc). This review is intended to summarize and critically discuss the redox mechanisms involved during the ageing process: sources of oxidant agents in ageing (mitochondrial -electron transport chain, nitric oxide synthase reaction- and non-mitochondrial- Fenton reaction, microsomal cytochrome P450 enzymes, peroxisomal β -oxidation and respiratory burst of phagocytic cells), antioxidant changes in ageing (enzymatic- superoxide dismutase, glutathione-reductase, glutathion peroxidase, catalase- and non-enzymatic glutathione, ascorbate, urate, bilirubine, melatonin, tocopherols, carotenoids, ubiquinol), alteration of oxidative damage repairing mechanisms and the role of free radicals as signaling molecules in ageing.

In the recent years, engineered nanoparticles (NPs) such as PLGA or poly-lactic-co-glycolic acid, have raised a substantial interest due to their possible medical applications in vaccination, diagnostic imaging procedures, cancer therapy or sustained delivery of drugs. The main aim of the present work is to evaluate key oxidative stress parameters in several organs following NPs administration in an animal model. Our data shows that acute oral administration of PLGA NPs induces a change in the antioxidant status in both rat liver and spleen, but may not induce oxidative stress damage to cell structures such as lipid or protein oxidation.

Oxidative stress (OS) plays an important role in NAFLD molecular mechanism. Nanoencapsulation represents a novel strategy to enhance therapeutic potential of conventional drugs. Our study analyses the encapsulated vitamin E effect on lipid metabolism and oxidative stress biomarkers in NAFLD rats. Animals were divided into 3 groups : G1 - the normal diet group; G2- the high caloric diet group ; G3 - high-caloric diet group receiving PLGA-vit E, 50 mg / kg. Serum advanced human oxidative protein (AOPP), total antioxidant capacity (TAC) and vitamin E were analysed using ELISA technique. Our results showed significant increase of G2 GPT, ALP, GGT, TG, glucose, TC and AOPP, versus G1 ( P [ 0.05) and a significant decrease of G2 serum TAC and vitamin E versus G1 results ( p = 0.01 and 0.01). Vitamin E nanoparticles (G3) caused a significant increase of TAC and significant decrease of serum AOPP, versus G2 (p [ 0.01). Results showed a significant reduction of GPT, GGT, ALP, TG and total cholesterol ( p [0.05) in G3 versus G2. PLGA nanoparticles should be considered an attractive and promising alternative to improve the bioavailability and biological activity of vitaminE.

The aim of this study was to evaluate the relation between inflammatory markers and the preatherosclerotic marker - flow mediated dilation (FMD). Thirty obese children (10-16 years old) and twenty controls were involved. The plasma inflammatory markers: CRP, fibrinogen, leptin, TNF-a, IL-6 were measured. Ultrasounds were used for FMD measurement, chemiluminescence for monocyte respiratory burst (RB), ELISA for C peptide and spectrophotometry for usual parameters. In the obese children versus the lean ones, the FMD was lower (p[0.001), the plasma values for TNF-a were similar (1.68 pg/mL vs 1.54 pg/mL), while plasma IL-6 was increased (4.01 pg/mL vs. 2.02 pg/mL, p[0.05). These cytokines were negatively correlated with FMD (r=-0.42, p[0.05) and positively with RB (r=50, p[0.05). The FMD was negatively correlated (p[0.05) with the values for diastolic blood pressure (r = -0.47), waist circumference (r = -0.55), uric acid (r = -0.47) and atherosclerotic index (r = -0.37). In conclusion, in the obese children, inflammation, dyslipidaemia, blood pressure and oxidative stress act in a cluster reducing the elasticity of the vessel walls.

PLGA (Poli-lactic-co-glycolic acid) nanoparticles (NPs) are curently used as drug delivery systems for many types of drugs including antioxidants such as vitamin E. The main aim of our study was to test the antioxidant effects of PLGA-vitamin E on Wistar male rats. Two groups of Wistar rats received a hypercaloric diet for 21 days: the first group received besides the hypercaloric diet a daily dose of PLGA loaded with vitamin E and the control group received only the hypercaloric diet. Spleen cellular lysate has been used to detect biomarkers of oxidative stress such as malondialdehyde, glutathione, advanced human oxidative protein and vitamin E. After 3 weeks of treatment, statistical significant changes have been detected between the two groups.