Type 2 diabetes mellitus is associated with increased bone fragility and fracture risk. However, diabetes-associated alterations in structural properties of the bone remain unclear. The current study aims at characterising the cortical bone macroporosity by using nanofocus X-ray computed tomography (nanoCT) imaging. Additionally, the T2DM cancellous bone architecture was assessed. Eight-week-old male C57BL/6J mice received a high-fat diet for 14 weeks (HFD, 60% kcal from fat) and were compared with age-matched control animals (10% kcal from fat).Tibiae (n=7 and n=8 for HFD and control respectively) were scanned in fast scan mode at 2 μm isotropic voxel size with X-ray source power of 85 kV and 99 μA, 1mm Al filter, resulting in a 20 minutes scan time (Nanotom S). The images were reconstructed using phoenix datos|x 2 and analysed using CTAn (Bruker microCT). Statistical significance (p<0.05) was determined by a two sample Students t-test after assessing the homogeneity of variances. Midshaft tibia intracortical macroporosity was found to be significantly decreased in HDF mice compared with age-matched control (p=0.02; 0.29±0.05% vs 0.59±0.09%). Cortical thickness showed a statistical significant increase (+23%) in HFD mice compared to controls (266.4±3.8 μm vs 215.4±4.0 μm; p<0.001). With regard to the cancellous bone, the trabecular number was decreased (-29%) while the trabecular thickness and trabecular separation were increased in HFD mice (+26% and +10.9% respectively compared to controls; p<0.001 and p=0.002, respectively), resulting in an unaltered trabecular bone volume fraction between HFD and control groups. Insights into the bone microstructure by using nanoCT revealed HFD-related alterations in both cortical and trabecular compartments. In particular, a decrease in the cortical macroporosity was evidenced. Further characterisation of the cortical porosity is in progress by investigation at 1 μm voxel size in order to extract the cortical bone osteocyte network and separate it from the vascular porosity.
Disclosure: The authors declared no competing interests. MD is financed by Centre National de la Recherche Scientifique, GK by the Research Foundation-Flanders (FWO/12R4315N). GK and LG acknowledge support by the European Research Council (FP7/2007-2013)/ERC grant agreement n°279100. The X-ray computed tomography facilities of the Department of Materials Engineering KU Leuven were financed by the Hercules Foundation (AKUL09/001).