Sympathetic control of bone mass is regulated by osteopontin

Activation of the sympathetic nervous system is known to reduce bone mass through mechanisms that remain unclear. Using cell-based studies and murine genetics, the authors [1] showed that osteopontin (OPN) is required for the sympathetic activity on bone metabolism.

Osteopontin is a cytokine and one of the major members of noncollagenous extracellular matrix proteins of bone.
Read the rest of this entry »

Bone microarchitecture assessed by TBS predicts osteoporotic fracture independently of bone density

The measurement of bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) is the ‘‘gold standard’’ for diagnosing osteoporosis but does not directly reflect deterioration in bone microarchitecture. Trabecular bone score (TBS) is a novel measurement of the trabecular bone microarchitecture quantifying local variations in gray level. Like BMD, TBS can be measured from DXA scans.
Read the rest of this entry »

Sirt1 is a regulator of bone mass and a repressor of Sost encoding Sclerostin

Sirtuin 1 (Sirt1) is a member of the sirtuin family. The sirtuins are a family of evolutionarily highly conserved protein deacetylases that were found to regulate the lifespan in lower species and key cellular and metabolic functions in mammals. Sirt1 is a deacetylase that plays an important role in metabolism and in age-associated diseases.

Read the rest of this entry »

Evidence for osteocyte regulation of bone homeostasis through RANKL expression

Agrowing number of evidence suggests that osteocytes orchestrate bone homeostasis by regulating the number and activity of bone-forming osteoblasts and bone-resorbing osteoclasts.
Using cell fractionation and purification techniques, the authors of this study [1] demonstrated that osteocytes produced larger amounts of RANKL mRNA than osteoblasts.
Read the rest of this entry »

Is greater lumbar vertebral BMD associated with more disk degeneration ?

Although numerous studies have shown an association of osteoarthritis with greater bone mineral density (BMD) in peripheral extremities, the relationship between vertebral BMD and disk degeneration remains controversial, possibly due to the inadequacies of BMD and disk degeneration measures.

Read the rest of this entry »