Aging and intestinal polyamine metabolism in the rat

Area of Science:

• Gastroenterology
• Cell Biology
• Aging Research

Background:

• Aging is associated with hyperproliferation and delayed enzyme activity in small intestinal enterocytes.
• Starvation and refeeding can impair the control of these proliferative processes in aging rodents.
• Altered polyamine metabolism is often linked to changes in enterocyte proliferation.

Purpose of the Study:

• To investigate the effects of nutrient manipulation on cell numbers, ornithine decarboxylase (ODC) activity, and polyamine content in the jejunum and ileum of aging rats.
• To compare these parameters between young and aging Fischer rats under different nutritional states.

Main Methods:

• Studied cell numbers, ornithine decarboxylase (ODC) activity, and polyamine content (putrescine, spermine, spermidine) in jejunum and ileum.
• Utilized 4- to 5-month (young) and 26- to 27-month (aging) Fischer rats subjected to starvation and refeeding protocols.

Main Results:

• Cell numbers decreased during starvation and increased during refeeding in both age groups.
• Aging rats exhibited jejunal crypt cell hyperplasia and higher jejunal putrescine, spermine, and spermidine content.
• Ileal ODC activity was significantly higher in aging rats, while jejunal ODC activity was only modestly increased in younger animals.

Conclusions:

• Intestinal polyamine content correlates with proliferative changes and responds appropriately to nutrient manipulation during aging.
• A dissociation between ODC activity and polyamine content in the aging jejunum suggests delayed enterocyte differentiation.
• Studying intestinal polyamine metabolism may help understand deranged proliferative activities in aging rodents.