Rapid increase in human life expectancy: will it soon be limited by the aging of elastin?

The postponement of the most frequent age-related diseases stimulated speculations of the possibility of "dying of old age". The selective decline of individual physiological functions-aging in spare-parts-indicates however the potential limitation of the life-span by the rapid decline of some of the vital parameters. We explored a possibility of such a limitation of maximal life-span by the age-related alteration of elastin, consisting in Ca-accumulation, lipid deposition and elastolytic degradation. The quantitative evaluation of these processes suggests an approximative upper limit for the elastic properties of the cardio-respiratory system of about 100-120 years, at least, as far as elastin is involved. This process, age-related alterations of elastic fibers, is however not the only one limiting the functional value of the cardiovascular system. Crosslinking of collagen fibers by advanced glycation end-products certainly contributes also to the age-dependent rigidification of the cardiovascular system. Therefore the answer to the initial question, can age-dependent alterations of a single matrix macromolecule be limiting such vital functions as the cardio-respiratory system-is a cautious yes, with however the caveat that other, independent mechanisms, such as the Maillard reaction, can also interfere with and limit further the functional value of such vital physiological functions.