Bone histomorphometry: Standardization of nomenclature, symbols, and units: Report of the asbmr histomorphometry nomenclature committee

135

Cancers that grow in bone, such as myeloma and breast cancer metastases, cause devastating osteolytic bone destruction. These cancers hijack bone remodeling by stimulating osteoclastic bone resorption and suppressing bone formation. Currently, treatment is targeted primarily at blocking bone resorption, but this approach has achieved only limited success. Stimulating osteoblastic bone formation to promote repair is a novel alternative approach. We show that a soluble activin receptor type IIA fusion protein (ActRIIA.muFc) stimulates osteoblastogenesis ( p < .01), promotes bone formation ( p < .01) and increases bone mass in vivo ( p < .001). We show that the development of osteolytic bone lesions in mice bearing murine myeloma cells is caused by both increased resorption ( p < .05) and suppression of bone formation ( p < .01). ActRIIA.muFc treatment stimulates osteoblastogenesis ( p < .01), prevents myeloma-induced suppression of bone formation ( p < .05), blocks the development of osteolytic bone lesions ( p < .05), and increases survival ( p < .05). We also show, in a murine model of breast cancer bone metastasis, that ActRIIA.muFc again prevents bone destruction ( p < .001) and inhibits bone metastases ( p < .05). These findings show that stimulating osteoblastic bone formation with ActRIIA.muFc blocks the formation of osteolytic bone lesions and bone metastases in models of myeloma and breast cancer and paves the way for new approaches to treating this debilitating aspect of cancer. ß

“…BFR/BS (mm 3 /mm 2 /day) was calculated as [MAR Â (dL þ 0.5sL)]/BS. (37) Assessing tumor burden and survival in studies in the 5T2MM and 5T33MM models of myeloma…”

Section: Histologic and Histomorphometric Analysismentioning

confidence: 99%

Inhibiting activin-A signaling stimulates bone formation and prevents cancer-induced bone destruction in vivo

Chantry

Heath

Mulivor

et al. 2010

135

“…(19) Measurements were performed in the secondary spongiosa in the metaphyseal area (0.5 mm below the growth plate) at the distal end of the femur. The parameter measured for bone volume was the total bone volume per tissue volume (BV/TV, %).…”

Section: Histomorphometrymentioning

confidence: 99%

The calcium-sensing receptor and 25-hydroxyvitamin D–1α-hydroxylase interact to modulate skeletal growth and bone turnover

Richard

Huo

Samadfam

et al. 2010

We examined parathyroid and skeletal function in 3-month-old mice expressing the null mutation for 25-hydroxyvitamin D-1a-hydroxylase [1a(OH)ase À/À ] and in mice expressing the null mutation for both the 1a(OH)ase and the calcium-sensing receptor [Casr À/À 1a(OH)ase À/À ] genes. On a normal diet, all mice were hypocalcemic, with markedly increased parathyroid hormone (PTH), increased trabecular bone volume, increased osteoblast activity, poorly mineralized bone, enlarged and distorted cartilaginous growth plates, and marked growth retardation, especially in the compound mutants. Osteoclast numbers were reduced in the Casr À/À 1a(OH)ase À/À mice. On a high-lactose, high-calcium, high-phosphorus ''rescue'' diet, serum calcium and PTH were normal in the 1a(OH)ase À/À mice but increased in the Casr À/À 1a(OH)ase À/À mice with reduced serum phosphorus. Growth plate architecture and mineralization were improved in both mutants, but linear growth of the double mutants remained abnormal. Mineralization of bone improved in all mice, but osteoblast activity and trabecular bone volume remained elevated in the Casr À/À 1a(OH)ase À/À mice. These studies support a role for calcium-stimulated maturation of the cartilaginous growth plate and mineralization of the growth plate and bone and calcium-stimulated CaSR-mediated effects on bone resorption. PTH-mediated bone resorption may require calcium-stimulated CaSR-mediated enhancement of osteoclastic activity. ß

“…Dynamic histomorphometric parameters for all sites included mineralizing surface (MS/BS), mineral apposition rate (MAR), and bone-formation rate (BFR/BS), as described elsewhere. (27) Statistical analyses Statistical analyses were performed in GraphPad Prism (Version 5.01, GraphPad Software, Inc., San Diego, CA, USA) for the rat study and SAS (Version. 8.1, SAS Institute, Inc., Cary, NC, USA) for the nonhuman primate study.…”

Section: Nonfractured Bone Analysesmentioning

confidence: 99%

Inhibition of sclerostin by monoclonal antibody enhances bone healing and improves bone density and strength of nonfractured bones

Ominsky

et al. 2010

240

212

Therapeutic enhancement of fracture healing would help to prevent the occurrence of orthopedic complications such as nonunion and revision surgery. Sclerostin is a negative regulator of bone formation, and treatment with a sclerostin monoclonal antibody (Scl-Ab) results in increased bone formation and bone mass in animal models. Our objective was to investigate the effects of systemic administration of Scl-Ab in two models of fracture healing. In both a closed femoral fracture model in rats and a fibular osteotomy model in cynomolgus monkeys, Scl-Ab significantly increased bone mass and bone strength at the site of fracture. After 10 weeks of healing in nonhuman primates, the fractures in the Scl-Ab group had less callus cartilage and smaller fracture gaps containing more bone and less fibrovascular tissue. These improvements at the fracture site corresponded with improvements in bone formation, bone mass, and bone strength at nonfractured cortical and trabecular sites in both studies. Thus the potent anabolic activity of Scl-Ab throughout the skeleton also was associated with an anabolic effect at the site of fracture. These results support the potential for systemic Scl-Ab administration to enhance fracture healing in patients. ß