Effects of Cortical Bone Hydration on Skeletal Fragility

 

   

 

Skeletal fragility due to the aging and disease (i.e., osteoporosis, osteopetrosis and osteopenia) is a major social-health problem affecting the lives of millions of people. Accurate assessment of fracture risk would help timely inception of therapy or help avoid unnecessary treatments. The literature has shown that bone mineral density (BMD)-based diagnosis cannot assess bone fragility with high accuracy and there is a need for more accurate diagnostic techniques. Last decade of studies showed bound water to be predictive of skeletal fragility. Despite known effects of dehydration on dried bone mechanical properties, the exact function and contribution of different water compartments to bone mechanical integrity is not fully understood since bound water is an elusive variable to be measured nondestructively. The only nondestructive method used for studying bone hydration status is magnetic resonance variants (NMR or MRI) which mostly detect signal from water bound to organic matrix (e.g., collagen) and unbound water, but they do not provide information on water that is bound to mineral exclusively. These techniques are not also able to distinguish among the bound water compartments that have various energy levels. Therefore, a broader range of methods are needed to infer the status of water compartments that may independently a role in contributing to bone mechanical properties. Recently, we developed a novel method to study on effects of hydration on skeletal fragility using custom designed short-wave infrared (SWIR) Raman spectroscopy. While MR-based techniques have been useful in measuring unbound and bound water, this is the first method which probed bound-water compartments differentially for collagen and mineral-bound water.

Using this novel method, for the first time, we showed an evidence for contribution of different water compartments in bone to mechanical properties of wet bone.

 

Publications:

 

·         Mustafa Unal, Shan Yang, Ozan Akkus Molecular spectroscopic identification of the water compartments in bone. Bone 2014; 67: 228-236.

Conferences:

·         Mustafa Unal, Shan Yang, Ozan Akkus: Molecular Spectroscopic Identification of Water Compartments in Bone. 7th World Congress of Biomechanics, Boston, MA, USA; 07/2014

·         Mustafa Unal, Ozan Akkus: A Computational Analysis of the Effect of Hydroxyproline on Bound Water and the Stability of Collagen. 7th World Congress of Biomechanics, Boston, MA, USA; 07/2014

·         Mustafa Unal, Ozan Akkus: Association of Bound and Unbound Water Compartments of Bone with Mechanical Properties. American Society of Biomechanics Midwest Regional Meeting, Akron, OH, USA 02/2015

·         Mustafa Unal, Ozan Akkus: Collagen Bound Water is a Strong Correlate of Bone’s Toughness. Summer Biomechanics, Bioengineering and Biotransport Conference (S3BC), Snowbird Resort, Utah, USA; 06/2015

·         Mustafa Unal, Ozan Akkus: Assessment of Bone Quality by Novel Spectroscopic Biomarkers. 39th Annual Meeting of the American Society of Biomechanics, Columbus, OH, USA; 08/2015