Intestinal lipid esterification and aging in mice and rats

Area of Science:

• Gerontology
• Lipid Metabolism
• Gastrointestinal Physiology

Background:

• Dietary lipid absorption is crucial for nutrient uptake.
• Aging can alter physiological processes, including digestion and nutrient absorption.
• Specific enzymes in the intestinal mucosa play key roles in fatty acid esterification.

Purpose of the Study:

• To investigate the impact of aging on lipid absorption in mice and rats.
• To examine the age-related changes in key intestinal enzymes involved in fatty acid esterification.
• To determine how different fatty acids affect enzyme activity in aging animals.

Main Methods:

• Assayed two intestinal mucosa microsomal enzymes: acylCoA:2-monoacylglycerol acyltransferase and acylCoA:1-lysophosphatidylcholine acyltransferase.
• Studied enzyme activities in 2.5-, 12-, and 24-month-old mice and rats.
• Varied the type of acyl-CoA substrate (oleoyl-CoA, linoleoyl-CoA, palmitoyl-CoA, arachidonoyl-CoA) to assess enzyme specificity.

Main Results:

• AcylCoA:2-monoacylglycerol acyltransferase activity showed no significant age-related decline in mice or rats.
• AcylCoA:1-lysophosphatidylcholine acyltransferase activity significantly decreased by 47% in 24-month-old rats compared to 2.5-month-old rats for specific acyl-CoA substrates.
• Older rats exhibited reduced glycerophospholipid esterification of oleic and linoleic acids compared to younger rats.

Conclusions:

• Aging significantly impairs acylCoA:1-lysophosphatidylcholine acyltransferase activity in rat intestinal mucosa.
• Reduced enzyme activity in aging rats leads to decreased glycerophospholipid esterification of dietary fatty acids.
• These findings highlight age-related changes in lipid metabolism and absorption efficiency.