"To add life to years, not years to life" is an adage found on the cover page of the first issue of the Journal of Biogerontology. This sentence summarizes what the state of mind of ageing research is in our days.

Ageing is a progressive deterioration of physiological functions that impairs the ability of an organism to maintain homeostasis and makes as a consequence this organism more susceptible to diseases and death. The nature and the progression of these declines vary between species as well as between the individuals of same specie. Life span among animals is indeed highly diverse ranging from a few hours (adult form of Ephemera insect) to 150 years (giant tortoise). This huge discrepancy between animal species renders the discovery of the factors underlying the ageing process and the determinants of the maximal length of life, major scientific interests.

During the last decades, human life expectancy in the industrialized countries has remarkably increased, and the proportion of aged people over 80 years old will continue to augment in the following years. Although this is an essentially positive outcome from multiple improvements in health care and socioeconomic circumstances, it nevertheless presents a growing anxiety for all member and associated states of the European Union in terms of increasing prevalence of age-related health problems and the growing financial implications for social security including pensions costs.

Thus, research that can lead to novel intervention to improve quality of life at older age has the potential for enormous impact in an ever-ageing society. Recent advances indicate that it is possible to intervene positively in the mechanisms that cause age-related frailty, disability and disease, particularly by developing and exploiting the fields of genomics (integrative analysis of genome, the carrier of genetic information) and biotechnology for health in old age. These fundamental advances in science and technology offer exciting opportunities to extend the period of good quality and healthy life as well as functional independence for the elderly people, and to develop European industries addressing the challenges of age. 

Why do we age?

Ageing is often considered as being driven by a biological clock. However, we need to keep in mind that ageing is hardly observable in natural populations where death is mainly occurring at early age from accidents, predation, starvation, infection, cold and so on and so forth. This is only in protected environment (laboratories for mice and rats, zoo for several animals species or the protected western societies for humans) that the life expectancy and the ageing process can be observed and analysed. So in that context, it is difficult to explain how a biological clock would have evolved under the natural selection as the animals are not living in the wild till an age at which the effects of the clock become apparent. An important pressure is exerted on animals to adapt to continuous changing life conditions and to assure the dissemination of their genes to their offspring. So equilibrium exist between the metabolic resources allocated to reproduction on one hand and to the maintenance and repair of all physiological functions on the other hand. When reproduction is ensured, no energy is wasted on long-term maintenance of the adult bodies: ageing process is launched. Although this may be frightening for humans, organisms must come and go if evolution is to work properly.

What are the mechanisms underlying the ageing process?

Ageing process is intricate and the comprehension of its molecular mechanisms is still puzzling the research community. Although today we may determine with better accuracy what are its main driving components.

The primary cause of ageing is the accumulation of damages at the molecular, cellular and tissue level. All along the life, numerous damages target macromolecules like DNA (deoxyribonucleic acid), proteins, lipids, e.g. all cellular constituents. Damages in DNA results in mutations and may lead to several types of cancers. Damages also accumulated into the protein constituents of the cells which can contribute to several age-disorders as cataracts, Alzheimer and Parkinson* diseases. The causes of damages are multiples although, accumulation of evidences identifies oxygen reactive species (=oxidative stress) as an important source of damages to cell structure and function. The principal source of oxygen reactive species in aerobic cells is the mitochondria, the respiration factory. During the several hundred million years of evolution, aerobic live evolved through adaptive processes for survival in an oxygen environment. Indeed, organisms developed different antioxidant mechanisms. Nevertheless, oxygen reactive species appear early in the organism and during ageing they do accumulate even more due to several mechanisms as an increasing production in the mitochondria, a reduction in oxidised protein and DNA repair and a decreased degradation of damaged proteins. Other factors as human over-pollution or inadequate nutrition also strongly influence the damage processes.