Tom Kirkwood is Professor of Medicine, Director of the Institute for Ageing and Health at the University of Newcastle, and Director of the BBSRC Centre for Integrated Systems Biology of Ageing and Nutrition. Educated in biology and mathematics at Cambridge and Oxford, he worked at the National Institute for Medical Research, where he formed and led a new research division, until in 1993 he became Professor of Biological Gerontology at the University of Manchester. His research is focused on the basic science of ageing and on understanding how genes as well as non-genetic factors, such as nutrition, influence longevity and health in old age.He is European President (Biology) of the International Association of Gerontology.
He chaired the UK Foresight Task Force on "Healthcare and Older People", was Specialist Adviser to the House of Lords Science & Technology Select Committee inquiry into "scientific aspects of ageing" and has served on the Councils of BBSRC and the Academy of Medical Sciences. He is European Editor of Mechanisms of Ageing and Development and serves on the editorial boards of eight other journals. He has published more than 300 scientific papers and won several international prizes for his research. His books include the award-winning "Time of Our Lives: The Science of Human Ageing", "Chance, Development and Ageing" (with Caleb Finch) and "The End of Age" based on his BBC Reith Lectures in 2001.
Making sense of the complexity of ageing
The continuing increase in life expectancy, which in many countries advances by five hours per day, is one of humanity's most astonishing successes. But success brings challenges, and population ageing requires radically new approaches to unravel the complex biology of ageing and its links with frailty and disease. The ageing process is particularly suited to a systems-biology approach, since its mechanisms are multiple, complex, highly interactive and often stochastic in nature. Indeed, a longstanding barrier to progress has been the coexistence of multiple, seemingly competing hypotheses about causal mechanisms. Each mechanism tends to be partially supported by data indicating that it has a role in the overall cellular and molecular pathways underlying the ageing process. However, the magnitude of this role is usually modest. The systems biology approach which combines (i) data-driven modeling, often using the large volumes of data generated by functional genomics technologies, and (ii) hypothesis-driven experimental studies to investigate causal pathways and identify their parameter values in an unusually quantitative manner enables the contributions of individual mechanisms and their interactions to be better understood and it allows for the design of experiments explicitly designed to test the complex predictions arising from such models. Already there are examples of the success of the systems biology approach in unraveling the complexity that underlies the phenomenon of cell replicative senescence, the so-called Hayflick Limit.
The processes underlying ageing appear to comprise a network of (random) damage and (genetically specified) signalling pathways. Genetic effects on the rate of ageing are mediated primarily through genes influencing somatic maintenance and repair, which may respond to environmental cues, particularly the level and quality of nutrients. At a time when the power of modern genetics is being used to conduct genome-wide studies of loci that are linked to human longevity, we can anticipate that systems biology will play a crucial role in helping to understand the inevitably complex genetics of healthy ageing. It is probably not overstating the position to assert we will not understand ageing without the aid of systems approaches.