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Proteoglycan Dynamics and Bone Quality: Molecular Regulation to Age-Related Fragility
Savannah Heath1, Rui Hua1, Xiaodu Wang2
1Biochemistry and Structural Biology Department, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Biomolecules
|May 4, 2026
Summary
Bone mineral density (BMD) is insufficient for predicting fractures. This review highlights how decreased glycosaminoglycans (GAGs) in aging bone compromise tissue toughness and quality, suggesting new therapeutic targets.
Area of Science:
- Bone biology and aging research
- Biomaterials and tissue engineering
Background:
- Bone mineral density (BMD) explains limited variance in bone fragility fractures.
- The non-collagenous organic matrix, particularly proteoglycans (PGs) and glycosaminoglycans (GAGs), plays a crucial role in bone quality and toughness.
- Aging is associated with decreased GAG levels in cortical bone, impacting tissue toughness.
Purpose of the Study:
- To examine the dynamic and mechanistic role of PGs and GAGs in maintaining bone toughness and quality.
- To analyze the causes of age-related GAG loss in bone.
- To discuss interventions for preserving GAGs/PGs to improve bone quality.
Main Methods:
- Literature review and analysis of existing data on bone matrix composition, aging, and biomechanics.
- Examination of the relationship between GAG levels, bone remodeling, and tissue aging.
- Discussion of the functional importance of PG/GAG metabolism and its link to inflammation and systemic aging.
Main Results:
- Aging leads to a significant decrease in cortical GAG levels (up to ~17%), correlating with reduced bone tissue toughness.
- Age-related GAG loss is linked to uncoupled bone remodeling, tissue aging, and impaired osteocyte function.
- Perturbations in PG/GAG metabolism can promote pro-inflammatory signaling, accelerating matrix degradation and systemic aging.
Conclusions:
- GAGs are critical determinants of bone quality and toughness, beyond BMD.
- Age-related changes in GAGs contribute to bone fragility and systemic aging.
- Targeting PG/GAG preservation presents a promising therapeutic strategy for enhancing bone quality and preventing fractures.
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