Regional variations of vertebral trabecular bone microstructure with age and gender.
The vertebral trabecular bone has a complex three-dimensional (3D) microstructure, with inhomogeneous morphology. A thorough understanding of regional variations in the microstructural properties is crucial for evaluating age- and gender-related bone loss of the vertebra, and may help us to gain more insight into the mechanism of the occurrence of vertebral osteoporosis and the related fracture risks.


BACKGROUND
The aim of this study was to identify regional differences in 3D microstructure of vertebral trabecular bone with age and gender, using micro-computed tomography (micro-CT) and scanning electron microscopy (SEM).


METHODS
We used 56 fourth lumbar vertebral bodies from 28 women and men (57-98 years of age) cadaver donors. The subjects were chosen to give an even age and gender distribution. Both women and men were divided into three age groups, 62-, 77- and 92-year-old groups. Five cubic specimens were prepared from anterosuperior, anteroinferior, central, posterosuperior and posteroinferior regions at sagittal section. Bone specimens were examined by using micro-CT and SEM.


RESULTS
Reduced bone volume (BV/TV), trabecular number (Tb.N) and connectivity density (Conn.D), and increased structure model index (SMI) were found between ages 62 and 77 years, and between ages 77 and 92 years. As compared with women, men had higher Tb.N in the 77-year-old group and higher Conn.D in the 62- and 77-year-old groups. The central and anterosuperior regions had lower BV/TV and Conn.D than their corresponding posteroinferior region. Increased resorbing surfaces, perforated or disconnected trabeculae and microcallus formations were found with age.


CONCLUSIONS
Vertebral trabeculae are microstructurally heterogeneous. Decreases in BV/TV and Conn.D with age are similar in women and men. Significant differences between women and men are observed at some microstructural parameters. Age-related vertebral trabecular bone loss may be caused by increased activity of resorption. These findings illustrate potential mechanisms underlying vertebral fractures.
Chen
H
H
Department of Anatomy, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu, 501-1194, Japan. huayue@gifu-u.ac.jp
Shoumura
S
S
Emura
S
S
Bunai
Y
Y
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000473:pathology*; D012737:Sex Factors; D055114:X-Ray Microtomography