Abstract:
Context: Increased bone fragility and reduced energy absorption to fracture associated
with type 2 diabetes (T2D) cannot be explained by bone mineral density alone. This study,
for the first time, reports on alterations in bone tissue’s material properties obtained
from individuals with diabetes and known fragility fracture status.
Objective: To investigate the role of T2D in altering biomechanical, microstructural, and
compositional properties of bone in individuals with fragility fracture.
Methods: Femoral head bone tissue specimens were collected from patients who
underwent replacement surgery for fragility hip fracture. Trabecular bone quality
parameters were compared in samples of 2 groups, nondiabetic (n = 40) and diabetic
(n = 30), with a mean duration of disease 7.5 ± 2.8 years. Results: No significant difference was observed in aBMD between the groups. Bone
volume fraction (BV/TV) was lower in the diabetic group due to fewer and thinner
trabeculae. The apparent-level toughness and postyield energy were lower in those with
diabetes. Tissue-level (nanoindentation) modulus and hardness were lower in this group.
Compositional differences in the diabetic group included lower mineral:matrix, wider
mineral crystals, and bone collagen modifications—higher total fluorescent advanced
glycation end-products (fAGEs), higher nonenzymatic cross-link ratio (NE-xLR), and
altered secondary structure (amide bands). There was a strong inverse correlation
between NE-xLR and postyield strain, fAGEs and postyield energy, and fAGEs and
toughness.
Conclusion: The current study is novel in examining bone tissue in T2D following first hip
fragility fracture. Our findings provide evidence of hyperglycemia’s detrimental effects
on trabecular bone quality at multiple scales leading to lower energy absorption and
toughness indicative of increased propensity to bone fragility.
