Bone Remodeling and Energy Metabolism: New Perspectives

Paula, Francisco José Albuquerque de; Rosen, Clifford J.

doi:10.4248/br201301005

Cited by 60 publications

(57 citation statements)

References 140 publications

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“…Interestingly, the expression of osteocalcin, a gene down-regulated by glucocorticoids, is higher in OG2-11βHSD2 transgenic mice when compare to age and gender matched wild-type animals (63). There is now mounting evidence that osteocalcin is involved in the regulation of normal fuel metabolism (70)(71)(72)(73)(74)(75)(76) and recent research suggests that the peptide plays a central role in the pathogenesis of glucocorticoid-induced dysmetabolism (77). Up to date, it is not known whether the age-related changes in body composition and fuel metabolism involve the action of endogenous glucocorticoid on osteoblast function, specifically via osteocalcin.…”

Section: Role Of Endogenous Glucocorticoids In Bone During Agingmentioning

confidence: 99%

Endogenous Glucocorticoids and Bone

2013

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While the adverse effects of glucocorticoids on bone are well described, positive effects of glucocorticoids on the differentiation of osteoblasts are also observed. These paradoxical effects of glucocorticoids are dose dependent. At both physiologicaland supraphysiological levels of glucocorticoids, osteoblasts and osteocytes are the major glucocorticoid target cells. However, the response of the osteoblasts to each of these is quite distinct. At physiology levels, glucocorticoids direct mesenchymal progenitor cells to differentiate towards osteoblasts and thus increase bone formation in a positive way. In contrast with ageing, the excess production of glucocorticoids, at both systemic and intracellular levels, appear to impact on osteoblast and osteocytes in a negative way in a similar fashion to that seen with therapeutic glucocorticoids. This review will focus on therole of glucocorticoids in normal bone physiology, with particular emphasis on the mechanism by which endogenous glucocorticoids impact on bone and its constituent cells. Keywords: glucocorticoids; mechanisms of action; bone; osteoblasts; skeletal development; Wnt signaling Bone Research (2013) 2: 107-119. doi: 10.4248/BR201302001 IntroductionThe adverse effects of high dose therapeutic glucocorticoids on bone are well described and include osteoporosis and osteonecrosis. These effects are primarily mediated through toxic effects on osteoblasts (the bone forming cells) and osteocytes (long-lived cells related to osteoblasts which are resident within bone tissue). By contrast, it is also clear that glucocorticoids have an important and often essential role in the differentiation of osteoblasts cultured in vitro. These data suggest that endogenous glucocorticoids could have a positive, rather than a negative, effect on bone development and metabolism. Resent in vivo studies have advanced our knowledge of the effects of endogenous glucocorticoids on bone and bone cells. The data obtained from experiments utilizing genetically modified mouse models demonstrate that glucocorticoids direct cell lineage commitment of early mesenchymal progenitors through effects on osteoblasts. These actions, at least in part, are regulated through the Wnt/β-catenin signaling pathway in mature osteoblasts. This glucocorticoid regulated signaling pathway within mature osteoblasts is essential for normal intramembranous (i.e. calvarial) bone development. During bone modeling and remodeling, glucocorticoids also appear to play an important positive role in maintaining bone structure. However, with ageing, these beneficial effects of endogenous glucocorticoidsare less evident and may in fact be detrimental e.g. causing bone loss and reduced levels of proteins associated with bone formation such as osteocalcin. These detrimental actions appear to result from a combination of a subtle increase in circulating glucocorticoid levels with age and an increased local production of glucocorticoids within osteoblasts with age. This review will discuss the effects of endogenous glucoc...

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Section: Role Of Endogenous Glucocorticoids In Bone During Agingmentioning

confidence: 99%

Endogenous Glucocorticoids and Bone

2013

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“…Bone remodeling is furthermore necessary to maintain the structural integrity of bone and is involved in the homeostasis of calcium and phosphate (Francillon‐Vieillot et al. ; de Paula & Rosen, ). It is also involved in bone healing processes as a dramatically accelerated response in regions of bone injury (Shih & Norrdin, ).…”

Section: Introductionmentioning

confidence: 99%

“…Bone remodeling consists in the resorption of bone tissue, i.e. the formation of resorption cavities (by osteoclasts), followed by deposition of secondary bone at the same location (by osteoblasts), forming secondary osteons (Francillon-Vieillot et al 1990;de Paula & Rosen, 2013). Remodeling involves a continuous replacement and a constant renewing of bone material.…”

Section: Introductionmentioning

confidence: 99%

Bone cortical compactness in ‘tree sloths’ reflects convergent evolution

2018

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Bone remodeling, one of the main processes that regulate bone microstructure, consists of bone resorption followed by the deposition of secondary bone at the same location. Remodeling intensity varies among taxa, but a characteristically compact cortex is ubiquitous in the long bones of mature terrestrial mammals. A previous analysis found that cortical bone in a few 'tree sloth' (Bradypus and Choloepus) specimens is heavily remodeled and characterized by numerous immature secondary osteons, suggesting that these animals were remodeling their bones at high rate until late in their ontogeny. This study aims at testing if this remodeling is generally present in 'tree sloths', using a quantitative analysis of the humeral cortical compactness (CC) among xenarthrans. The results of the investigation of humeral diaphyseal cross-sections of 26 specimens belonging to 10 xenarthran species including specimens from both extinct and extant species indicate that in 'tree sloths' the CC is significantly lower than in the other sampled xenarthrans. No significant difference was found between the CC of the two genera of 'tree sloths'. Our results are consistent with the hypothesis that the cortical bone of 'tree sloths' in general undergoes intense and balanced remodeling that is maintained until late (possibly throughout) in their ontogeny. In the light of xenarthran phylogeny, low CC represents another convergence between the long-separated 'tree sloth' lineages. Although the exact structural and/or functional demands that are associated with this trait are hitherto unknown, several hypotheses are suggested here, including a relationship to their relatively low metabolism and to the mechanical demands imposed upon the bones by the suspensory posture and locomotion, which was independently acquired by the two genera of 'tree sloths'.

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“…The primary functions of intestine and adipose tissue—absorption of nutrients and storage of energy, respectively—are both closely related to and greatly affect bone and metabolic homeostasis . In addition, the intestine is responsible for critical endocrine activity that is intimately linked to the modulation of appetite and energy balance .…”

Section: Introductionmentioning

confidence: 99%

Short bowel syndrome: influence of nutritional therapy and incretin GLP1 on bone marrow adipose tissue

Parreiras-e-Silva

Araújo

Elías

et al. 2018

Annals of the New York Academy of Sciences

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Energy deprivation leads to a decrease in white adipose tissue and bone mineral density (BMD), while simultaneously inducing the expansion of marrow adipose tissue (MAT). In short bowel syndrome (SBS), parenteral nutrition mitigates the deterioration of nutritional status, including decreases in MAT. Osteoporosis is, however, a frequent complication of SBS. The objective of our study here was to evaluate the association of fat deposit sites (subcutaneous and visceral adipose tissues: intrahepatic lipid (IHL) and MAT) and the incretin glucagon-like peptide 1 (GLP1) with BMD in individuals with SBS. MAT was negatively correlated with lumbar spine BMD in normal individuals, but not in those in the SBS group, who otherwise showed a positive correlation between MAT and GLP1. In addition, in individuals with SBS, IHL was negatively associated with lumbar spine BMD and positively associated with C-terminal telopeptide of type 1 collagen (a serum biomarker of bone turnover). Caloric maintenance in individuals with SBS, therefore, seems to positively affect the relationship between MAT and BMD, which may be modulated, at least in part, by GLP1.

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Bone Remodeling and Energy Metabolism: New Perspectives

Cited by 60 publications

References 140 publications

Endogenous Glucocorticoids and Bone

Endogenous Glucocorticoids and Bone

Bone cortical compactness in ‘tree sloths’ reflects convergent evolution

Short bowel syndrome: influence of nutritional therapy and incretin GLP1 on bone marrow adipose tissue

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