Dietary restriction in aged mice can partially restore impaired metabolism of apolipoprotein A-IV and C-III

Dietary restriction (DR) is only one well-established non-genetic experimental means to retard aging in various species of animals. Here we demonstrated that DR in mice for 3 months initiated late in life, at the age of 22 months, partially restores age-related decline of serum apolipoprotein A-IV (apo A-IV) level and the gene expression found in the liver of ad libitum fed young animals as revealed by fasting. In contrast, increase in gene expression of apo C-III by fasting was higher in the aged than that in the young, but it was reduced to the level of young animals in DR counterparts of the aged. In view of the implication that apo A-IV and C-III are involved in the activation and inhibition of lipoprotein lipase, respectively, the adult onset DR can conceivably upregulate the activity of this enzyme that is likely reduced in aged animals and thus improve the lipid metabolism. The present findings suggest that DR initiated even relatively late in life may reduce risk of age-related diseases associated with impaired lipid metabolism.