Telomerase confers limitless proliferative potential to most human cells through its ability to elongate telomeres, the natural ends of chromosomes, which otherwise would undergo progressive attrition and eventually compromise cell viability. However, the role of telomerase in organismal aging has remained unaddressed, in part because of the cancer-promoting activity of telomerase. To circumvent this problem, we have constitutively expressed telomerase reverse transcriptase (TERT), one of the components of telomerase, in mice engineered to be cancer resistant by means of enhanced expression of the tumor suppressors p53, p16, and p19ARF. In this context, TERT overexpression improves the fitness of epithelial barriers, particularly the skin and the intestine, and produces a systemic delay in aging accompanied by extension of the median life span. These results demonstrate that constitutive expression of Tert provides antiaging activity in the context of a mammalian organism.

The aim of this work was to study the mechanism of free radical formation in type 1 diabetes and its possible prevention. We have found oxidation of blood glutathione and an increase in plasma lipoperoxide levels in both human type 1 diabetes and experimental diabetes. Peroxide production by mitochondria does not increase in diabetes. On the contrary, the activity of xanthine oxidase, a superoxide-generating enzyme, increases in liver and plasma of diabetic animals. The increase in plasma xanthine oxidase activity may be explained by the increase in the hepatic release of this enzyme, which is not due to nonspecific membrane damage: release of other hepatic enzymes, such as the amino transferases, does not increase in diabetes. Superoxide formation by aortic rings of rabbits increases significantly in diabetes. This is completely inhibited by allopurinol, an inhibitor of xanthine oxidase. Heparin, which releases xanthine oxidase from the vessel wall, also decreases superoxide formation by aortic rings of diabetic animals. Treatment with allopurinol decreases oxidative stress in type 1 diabetic patients: hemoglobin glycation, glutathione oxidation, and the increase in lipid peroxidation are prevented. These results may have clinical significance in the prevention of late-onset vascular complications of diabetes.

The European Cooperation in Science and Technology (COST) provides an ideal framework to establish multi-disciplinary research networks. COST Action BM1203 (EU-ROS) represents a consortium of researchers from different disciplines who are dedicated to providing new insights and tools for better understanding redox biology and medicine and, in the long run, to finding new therapeutic strategies to target dysregulated redox processes in various diseases. This report highlights the major achievements of EU-ROS as well as research updates and new perspectives arising from its members. The EU-ROS consortium comprised more than 140 active members who worked together for four years on the topics briefly described below. The formation of reactive oxygen and nitrogen species (RONS) is an established hallmark of our aerobic environment and metabolism but RONS also act as messengers via redox regulation of essential cellular processes. The fact that many diseases have been found to be associated with oxidative stress established the theory of oxidative stress as a trigger of diseases that can be corrected by antioxidant therapy. However, while experimental studies support this thesis, clinical studies still generate controversial results, due to complex pathophysiology of oxidative stress in humans. For future improvement of antioxidant therapy and better understanding of redox-associated disease progression detailed knowledge on the sources and targets of RONS formation and discrimination of their detrimental or beneficial roles is required. In order to advance this important area of biology and medicine, highly synergistic approaches combining a variety of diverse and contrasting disciplines are needed.

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