Bone marrow fat accumulation accelerated by high fat diet is suppressed by exercise

Area of Science:

• Bone Biology and Metabolism
• Adipose Tissue Research
• Exercise Physiology

Background:

• Marrow adipose tissue (MAT) is linked to skeletal fragility and hematologic issues.
• Understanding and quantifying MAT is challenging.
• Its role in bone health requires further investigation.

Purpose of the Study:

• To investigate the impact of high-fat diet (HFD) and exercise on MAT.
• To compare MAT changes with bone quantity.
• To test the hypothesis that HFD increases MAT and exercise mitigates this effect while promoting bone formation.

Main Methods:

• Utilized a novel volumetric analysis with micro-computed tomography (μCT) and a lipid binder (osmium) for MAT quantification in mouse femurs.
• Employed semi-automated approaches including rigid co-alignment and regional bone masks.
• Normalized MAT to total femoral volume (TV) across regular diet (RD), HFD, RD with exercise (RD-E), and HFD with exercise (HFD-E) groups.

Main Results:

• HFD significantly increased femoral MAT by 2.6-fold compared to RD.
• Exercise (running wheel) suppressed MAT by over 50% in RD-E mice and inhibited MAT accumulation in HFD-E mice.
• Exercise significantly increased bone quantity in both diet groups.

Conclusions:

• High-fat diet consumption leads to substantial marrow adipose tissue accumulation.
• Running exercise effectively counteracts diet-induced MAT increase and promotes bone formation.
• Exercise's dual role in regulating MAT and bone quantity is significant for aging and sedentary populations.