Nanoscale Investigation of Bone Tissue near Lacunae of Trabecular Bone in Type-1 Diabetic Postmenopausal Women

Abstract

The goal of this study is to investigate the causes of skeletal fragility in Type 1 Diabetic (T1D) women. We hypothesize that bone fragility in diabetic individuals is partly due to changes in mineral and/or intrinsic material properties in the osteocyte lacunar/peri-lacunar regions of bone tissue. Studies of bone material properties in T1D are limited, and bone mineral density (BMD) alone does not explain the elevated fracture risk in T1D women (Cases). Innovative instruments with nanoscale resolution, including a laser scanning microscope (LSM), an atomic force microscope that is integrated with infrared spectroscopy (AFM-IR), and a nanoindenter were used for the characterization of the material properties surrounding osteocyte lacunae. In trabecular bone tissue, the compositional mineral matrix and Mineral Matrix Peak ratios (MMA, MMP for both near- & far-lacunae) along with material strength variables (Modulus, Hardness for both near- & far-lacunae) were lower in T1D compared to Controls. While material compositional ratio of mineral maturity crystallinity area (MMCA) was higher, the mineral maturity crystallinity peak (MMCP) and hardness tended to be higher in “lacunae-near” than “lacunae-far” for all the biopsies. Furthermore, the higher mineral matrix (MMA) and material strength (modulus, hardness) in peri-lacunar regions of Controls may suggest its increased brittleness or differences in properties as compared to T1D. We postulate that difference between Cases (T1D) and Controls in modulus and hardness could be due to the variation in mineral exchange (diffusion) rate within the peri lacunar space.