Bone Abstracts

In type 2 diabetes mellitus (T2DM) patients, an increased fracture risk is observed, although the bone mineral density is even higher than in non-diabetic patients. This raises the question of the quality of the organic and inorganic matrix in bone^1–3. T2DM is also known to forward dysfunctions in the development of soft tissues such as brittle skin due to cross-linking of the collagen or inflammation of the gingiva. For the latter, a possible influence of diabetes not only on the soft tissue but on the hard tissue motivated the current study. Using synchrotron small-angle X-ray scattering (SAXS) we investigated the nanostructure of the mandible and tooth of diabetic and healthy mice. Parameters to characterize bone quality are the amount, size (T- and L-parameter) and distribution (rho-parameter) of mineral particles in the organic matrix^4–5. The samples included embedded cross-sections of the jaw bone centered around the first molar of 15 week old standard healthy controls (C57BL/) and obese diabetes mice (KKAy). Line scans with 30 μm resolutions (beam- and stepsize) over the cross-section from the lingual side towards the tooth to the buccal side were performed. Significant differences in the nanostructure of the mineral particles of the bone between the lingual and buccal side were found. In particular, the mineral platelets are thicker and well more orientated on the buccal side compared to the lingual side in the control mice. In the presence of T2DM the measurements indicate a further increase of this structural difference between both sides toward the tooth. Reasons for this high asymmetry in the nanostructure of the bone in control as well as diabetes mice could be differences in the remodeling rates related with an unequal mechanical load on both sides of the tooth.

References

1. Hamann C, Kirschner S, Guenther K-P & Hofbauer LC. Nature Reviews Endocrinology (2012) 8, 297–305.

2. Vestergaard P, Rejnmark L & Mosekilde L. Calcified Tissue International (2009) 84, 45–55.

3. Rubin MR. Endocrine (2013) 43, 469–471.

4. Fratzl P, Fratzl-Zelman N, Klaushofer K, Vogl G & Koller K. Calcified Tissue International (1991) 48, 407–413.

5. Märten A, Fratzl P, Paris O & Zaslansky P. Biomaterials (2005) 31, 5479–5490.