Similarities Between Disuse and Age-Induced Bone Loss

Area of Science:

• Bone biology and osteoporosis research.

Background:

• Disuse and aging are primary risk factors for reduced bone mass and quality, leading to higher fracture incidence.
• Significant overlap exists in skeletal manifestations between disuse and aging, suggesting common underlying pathological processes.

Purpose of the Study:

• To review preclinical models of musculoskeletal disuse and their clinical relevance.
• To summarize shared skeletal alterations at organ, cellular, and molecular levels between disuse and aging.
• To identify potential therapeutic targets by understanding common mechanisms of bone loss.

Main Methods:

• Review of preclinical models of musculoskeletal disuse.
• Comparative analysis of bone loss mechanisms in disuse and aging across multiple scales.
• Exploration of shared molecular signaling pathways and cellular processes.

Main Results:

• Both disuse and aging lead to preferential cancellous bone loss, cortical thinning, and reduced bone strength.
• Cellularly, bone loss involves increased resorption, decreased formation, and enhanced adipogenesis via altered signaling pathways.
• Key shared molecular mechanisms include collagen cross-linking, AGE-RAGE signaling, ROS/NF-κB pathways, senescence, and altered mechanosensation.

Conclusions:

• Understanding shared mechanisms in bone loss due to disuse and aging is crucial for developing effective osteoporosis therapies.
• Targeting common pathways like AGE-RAGE, ROS, and cellular senescence may offer novel therapeutic strategies.