Matters Of Heart - Spring 2012

Loeys-Dietz Syndrome Affects Bone Microarchitecture, cont.

METHODS
Ten formalin-fixed femora obtained from 6-month-old LDS and wild-type mice were analyzed using a high-resolution µCT imaging system. Cortical and trabecular morphometric parameters were examined in diaphyseal and metaphyseal regions, respectively. Student's t-test with α=0.05 was employed to compare means.

RESULTS
Cortical parameters including bone volume, bone surface, and cortical thickness were consistent between groups. Trabecular parameters including bone surface density, proportion of bone volume in intramedullary canal, trabecular number, and trabecular thickness, however, were all significantly increased in LDS mice compared to wild-type mice.

DISCUSSION AND CONCLUSION
LDS mice exhibit heterogeneous bone microarchitecture and thicker, denser trabeculae that could be attributed to disorganized bone remodeling. Bone remodeling prevents propagation of bone microfractures produced by routine mechanical stressing. TGF-βs play a significant role in orchestrating bone remodeling. An uncoupling of remodeling might account for increased fractures and osteoporosis reported in LDS patients. Further studies examining the effect of LDS on TGF-β signaling pathways are underway.

Southern Orthopaedic Association Annual Meeting Abstract Submission January 5, 2012
Stuart Mitchell, BS1, Ashvin Dewan, MD1, Thomas Clemens, PhD1, Xu Cao, PhD1, Harry Dietz, MD2, Paul Sponseller, MD1

1Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
2 Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205

Click the poster below to download the full-size PDF. LDS Bone Microarchitecture Poster LDSF

   

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