Exercise reduces metabolic burden while altering the immune system in aged mice.

Area of Science:

• Immunology
• Metabolism
• Gerontology

Background:

• Aging phenotypes are linked to metabolic dysfunction.
• Exercise is known to prevent aging, but its effects on immune cell profiles in senile obesity are not well understood.

Purpose of the Study:

• To investigate the mechanisms by which exercise improves metabolic function in aged, obese mice by examining immune cell profiles in white adipose tissue (WAT).

Main Methods:

• Mice aged 88 weeks underwent 4 weeks of treadmill exercise.
• Assessed metabolic function (lean mass, fat mass).
• Analyzed senescence marker p16 expression in WAT.
• Characterized immune cell subsets in WAT stromal vascular fraction using flow cytometry.
• Performed transcriptome analysis of WAT.

Main Results:

• Exercise improved metabolic function, increasing lean mass and decreasing fat mass.
• Reduced expression of the senescence marker p16 in WAT.
• Altered immune cell profiles in WAT, including increases in natural killer (NK) cells, central memory CD8+ T cells, eosinophils, and neutrophils.
• Transcriptome analysis revealed exercise activated pathways related to WAT-immune cell interactions, particularly with NK cells.

Conclusions:

• Exercise effectively improves metabolic function and reduces cellular senescence in aged, obese mice.
• Exercise modulates immune cell distribution within WAT, promoting senescent cell clearance.
• These immune system changes induced by exercise contribute to a more youthful metabolic state in aged mice.