Meeting Abstract
S2.4 Monday, Jan. 4 Metabolism and Longevity: is there a role for membrane fatty acids? HULBERT, AJ; Univ. of Wollongong, Australia hulbert@uow.edu.au
Over 100 years ago, Max Rubner combined the fact that both metabolic rate and longevity of mammals varies with body size to calculate that “life energy potential” (lifetime energy turnover per kg) was relatively constant. This calculation linked longevity to aerobic metabolism which in turn lead to the “rate-of-living” and ultimately the “oxidative stress” theories of aging. However the link between metabolic rate and longevity is very imperfect. Although unknown in Rubner’s time, one aspect of body composition of mammals also varies with body size, namely the fatty acid composition of membranes. Fatty acids vary dramatically in their susceptibility to peroxidation and the products of lipid peroxidation are very powerful reactive molecules that damage other cellular molecules. The “membrane pacemaker” modification of the “oxidative stress” theory of aging proposes that membrane fatty acid composition, via its influence on lipid peroxidation, is an important determinant of lifespan (and a link between metabolism and longevity). The relationship between membrane fatty acid composition and longevity will be discussed for (i) mammals of different body size, (ii) birds of different body size, (iii) mammals and birds that are exceptionally long-living for their size, (iv) strains of mice that vary in longevity, (v) calorie-restriction extension of longevity in rodents, (vi) longevity differences between queen and worker honeybees, and (vii) longevity differences among humans. Most of these comparisons support an important role for membrane fatty acid composition in the determination of longevity. The regulation of membrane composition and especially the influence of fatty acid composition of the diet will be discussed. Consideration of the exceptionally long-living species, Homo sapiens, suggests the fatty acid composition of mitochondrial membranes may be especially important.
