Modulation of PPAR in aging, inflammation, and calorie restriction

Area of Science:

• Molecular Biology
• Gerontology
• Nutritional Science

Background:

• Peroxisome proliferator-activated receptors (PPARs) are crucial nuclear receptors regulating energy metabolism and inflammation.
• Limited data exists on the impact of aging and calorie restriction (CR) on PPARs.
• Kidney function is vital for metabolic homeostasis and susceptible to age-related changes.

Purpose of the Study:

• To investigate the effects of age and calorie restriction (CR) on PPAR expression and activity in rat kidneys.
• To determine if CR can counteract age-related decreases in PPARs.
• To explore the link between PPARs, aging, oxidative stress, and inflammation.

Main Methods:

• Analysis of nuclear protein levels, mRNA expression, and DNA binding activity of PPARs in kidneys from young (13-month) and old (25-month) Fischer 344 rats.
• Comparison between rats fed ad libitum and those subjected to 60% calorie restriction (CR).
• Validation of findings using lipopolysaccharide (LPS) injection to induce inflammation.

Main Results:

• PPAR nuclear protein, mRNA levels, and DNA binding activity significantly decreased with age in rat kidneys.
• Calorie restriction (CR) significantly blunted these age-associated reductions in PPARs.
• Age-related inflammation, exacerbated by LPS, was linked to altered PPAR expression.

Conclusions:

• Age-related decline in kidney PPARs may be associated with increased oxidative stress.
• Calorie restriction (CR) preserves PPAR expression and activity in aging kidneys, potentially via antioxidant mechanisms.
• Maintaining PPAR function through CR may be a strategy to mitigate age-related metabolic and inflammatory changes in the kidney.