Leukocyte telomere dynamics, human aging, and life span

This chapter takes stock of basic telomere research, it emphasizes telomere epidemiology to address the above-mentioned and other yet unresolved questions relating to human aging and longevity. These include questions such as: Does it matter for survival that one display shorter telomeres than many other mammals do? Are there any biological ramifications of having a long or short leukocyte telomere length (LTL)? What might be the explanation for the longer LTL in women than in men? And then, what does the steadily expanding list of associations between LTL and cardiovascular diseases (CVD) presents about the biology of aging and perhaps interindividual variation in human longevity? This discussion is based on empirical observations that link telomere biology to the human life span, it unfortunately cannot establish causality. In that light, only genetically engineered mouse models under- or overexpressing telomerase activity have thus far demonstrated a causal link between telomere length and life span. In this link there lurks the answer to what lies ahead for any attempt to reverse aging-related diseases and increase human longevity without factoring telomere biology into the life span equation.