@On the importance of fatty acid composition of membranes for aging (Hulbert 2004)

2022-02-08 links: @How might you compare mitochondria from different tissues and different species? (Hulbert et al. 2006)

@On the importance of fatty acid composition of membranes for aging (Hulbert, 2004) #

• This literature looks pretty interesting. Lots of similar papers.

• Membrane pacemaker theory of aging emphasizes variation in Fatty Acid composition as an important influence on Lipid Peroxidation and consequently Longevity/lifespan.

  • Acyl composition of membrane bilayers.

• Lifespan extension by calorie-restriction can also be explained by changes in membrane fatty acid composition which result in membranes more resistant to peroxidation. It is suggested that lifespan extension by reduced insulin/IGF signalling may also be mediated by changes in membrane fatty acid composition.

  • The link between MR and lifespan was suggested by Rubner in 1908 and elaborated into the rate of living theory by Pearl in 1928. There’s cited many reasons it’s probably bogus.
  • Within species there is no evidence of a direct connection between MR and lifespan (Speakman et al., 2000; Hulbert et al., 2004a) and no relationship between daily food consumption and individual lifespan (Hulbert et al., 2004c).

• Hypothyroidism affects membrane fatty acid composition with the most consistent finding being an decrease in the ratio of Arachidonic Acid:Linoleic Acid. The lowering of this ratio, with its consequent lowering of the peroxidation susceptibility of membranes, is a consistent finding of calorie-restriction.

• The accumulation of Lipofuscin in post-mitotic cells is the most consistent and phylogenetically constant morphological change of aging.

• DHA… is particularly important and its abundance in tissue [skeletal muscle] phospholipids is strongly correlated with body size in mammals and birds

• The Omega-3 PUFA are more peroxidation-prone than n-6 PUFA and within each PUFA class there is 4-fold increase in peroxidisability between the short- and long-chain fats. ==DHA (22:6) is 320-fold more susceptible to peroxidation than Oleic Acid (18:1).== When Lipid Peroxidation is induced in isolated liver cells there is no change in the fatty acid composition of phospholipids but a selective decrease in PUFA contents of triglycerides. This is because ==continual membrane remodelling eliminates peroxidised fatty acids in phospholipids replacing them with fresh PUFA from the Triglyceride pool.==