Relationship between bone formation rate and osteoblast surface on different subdivisions of the endosteal envelope in aging &amp; osteoporosis

Shih, Mei‐Shu; Cook, Megan; Spence, C. A.; Palnitkar, Saroj; McElroy, H; Parfitt, A. M.

doi:10.1016/8756-3282(93)90189-h

Cited by 34 publications

(13 citation statements)

References 5 publications

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“…This implies that, in osteoporotics, either fewer osteoblasts are recruited or that active osteoblasts are transformed quicker into less active ones. Our results suggest that the bone forming capacity per cell is reduced, which is compatible with the latter explanation of Shih et al 26 Furthermore, a decreased longevity of osteoblasts may explain that more are incorporated as osteocytes per bone volume. The reduced lacunar size may also indicate a history of reduced activity of these cells.…”

Section: Discussionsupporting

confidence: 91%

Osteocyte density changes in aging and osteoporosis

Mullender

Meer

Huiskes

et al. 1996

Bone

226

133

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Recently, it was suggested that osteocytes are involved in the regulation of bone remodeling. We have examined human trabecular bone of the iliac crest of fracture patients and control subjects to determine if osteoporosis is associated with changes in osteocyte density or osteocyte death. The relationships of these parameters with age was also investigated. It was found that osteocyte death was not related to age, nor was it increased in osteoporosis compared with the controls. In healthy adults ranging from 30 to 91 years, lacunar number per bone area decreases with advancing age, from about 210/mm 2 to 150/mm 2. Significantly higher lacunar and osteocyte numbers per bone tissue volume were found in osteoporotics than in controls (17,100 lacunae/mm 3 and 13,300 osteocytes/mm 3 vs. 12,900 lacunae/mm 3 and 10,500 osteocytes/mm 3, respectively), whereas lacunar area was significantly reduced in osteoporotics (from 44.1 ~tm 3 to 39.1 lam2). These findings are compatible with the hypothesis that, in osteoporosis, osteoblasts produce less bone per cell. This can in turn explain the reduced wall thickness, which has previously been described as characteristic for osteoporosis. (Bone 18:109-113; 1996)

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Section: Discussionsupporting

confidence: 91%

Osteocyte density changes in aging and osteoporosis

Mullender

Meer

Huiskes

et al. 1996

Bone

226

133

View full text Add to dashboard Cite

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“…At present, it is unclear why osteocyte lacunar density would be elevated as a consequence of hibernation, although it may be linked to changes in osteoblast function. Osteocyte lacunar density is also increased in osteoporotic humans relative to age-matched controls, and may reflect decreased bone formation activity per osteoblast [resulting in earlier cell entrapment in the bone matrix (Shih et al, 1993;Mullender et al, 1996)]. Consistent with this hypothesis, osteoblasts are less active during hibernation (Steinberg et al, 1986) and bone formation decreases in hibernating compared with active rodents (Tempel et al, 1978).…”

Section: Discussionsupporting

confidence: 67%

Thirteen-lined ground squirrels (Ictidomys tridecemlineatus) show microstructural bone loss during hibernation but preserve bone macrostructural geometry and strength

McGee‐Lawrence

Stoll

Mantila

et al. 2011

Journal of Experimental Biology

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SUMMARYLack of activity causes bone loss In most animals. Hibernating bears have physiological processes to prevent cortical and trabecular bone loss associated with reduced physical activity, but different mechanisms of torpor among hibernating species may lead to differences in skeletal responses to hibernation. There are conflicting reports regarding whether small mammals experience bone loss during hibernation. To investigate this phenomenon, we measured cortical and trabecular bone properties in physically active and hibernating juvenile and adult 13-lined ground squirrels (Ictidomys tridecemlineatus, previous genus name Spermophilus). Cortical bone geometry, strength and mineral content were similar in hibernating compared with active squirrels, suggesting that hibernation did not cause macrostructural cortical bone loss. Osteocyte lacunar size increased (linear regression, P0.001) over the course of hibernation in juvenile squirrels, which may indicate an osteocytic role in mineral homeostasis during hibernation. Osteocyte lacunar density and porosity were greater (+44 and +59%, respectively; P<0.0001) in hibernating compared with active squirrels, which may reflect a decrease in osteoblastic activity (per cell) during hibernation. Trabecular bone volume fraction in the proximal tibia was decreased (-20%; P0.028) in hibernating compared with physically active adult squirrels, but was not different between hibernating and active juvenile squirrels. Taken together, these data suggest that 13-lined ground squirrels may be unable to prevent microstructural losses of cortical and trabecular bone during hibernation, but importantly may possess a biological mechanism to preserve cortical bone macrostructure and strength during hibernation, thus preventing an increased risk of bone fracture during remobilization in the spring.

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“…Osteoporosis is a progressive disorder leading to low bone mass, increased bone fragility, and susceptibility to fractures [1,2] and is recognized as a major social health problem. It was considered a disease of postmenopausal women for a long time; however, osteoporosis in adult men is being increasingly recognized.…”

Section: Introductionmentioning

confidence: 99%