Animals ; Bone and Bones ; metabolism ; Energy Metabolism ; physiology ; Humans ; Osteocalcin ; metabolism

The prevailing model of osteology is that bones constantly undergo a remodeling process, and that the differentiation and functions of osteoblasts are partially regulated by leptin through different central hypothalamic pathways. The finding that bone remodeling is regulated by leptin suggested possible endocrinal effects of bones on energy metabolism. Recently, a reciprocal relationship between bones and energy metabolism was determined whereby leptin influences osteoblast functions and, in turn, the osteoblast-derived protein osteocalcin influences energy metabolism. The metabolic effects of bones are caused by the release of osteocalcin into the circulation in an uncarboxylated form due to incomplete gamma-carboxylation. In this regard, the Esp gene encoding osteotesticular protein tyrosine phosphatase is particularly interesting because it may regulate gamma-carboxylation of osteocalcin. Novel metabolic roles of osteocalcin have been identified, including increased insulin secretion and sensitivity, increased energy expenditure, fat mass reduction, and mitochondrial proliferation and functional enhancement. To date, only a positive correlation between osteocalcin and energy metabolism in humans has been detected, leaving causal effects unresolved. Further research topics include: identification of the osteocalcin receptor; the nature of osteocalcin regulation in other pathways regulating metabolism; crosstalk between nutrition, osteocalcin, and energy metabolism; and potential applications in the treatment of metabolic diseases.
Bone Remodeling/physiology ; Bone and Bones/*metabolism ; *Energy Metabolism ; Humans ; Leptin/metabolism ; Osteocalcin/genetics/*metabolism

OBJECTIVETo study the mechanism of new bone formation and remodeling of distraction osteogenesis (DO) by analysis of the expression of osteopontin (OPN) and osteocalcin (OC).

METHODSRhesus were operated to reconstruct the animal model of cleft palate (CP). The CP was closed by DO in experimental group(n = 21). After consolidation of 1, 2, 4, 6, 8, 12, 24 weeks, every 3 animals were killed to collect the specimens, respectively. The OPN and OC and their mRNA were detected quantitatively by Real-time RT-PCR and ELISA, respectively. The animals in control group (n = 2) and sham group (n = 2) were used as control.

RESULTSThe mRNA expression of OPN increased since 2nd week of consolidation and reached the peak at 4th week (7.59 +/- 0.37). The mRNA expression of OC was up-regulated since 4th week, and reach the peak at 6th week (7.94 +/- 0.31). Then they decreased to about the level in sham group at 24th week (P > 0.05). The OPN and OC were highly expressed during 4 to 6 weeks of consolidation. During 8 to 12 weeks, they decreased like their mRNA expression.

CONCLUSIONThe intramembraneous new bone formation after DO can reconstruct the bone defect of CP. The new formed bone can be remodeled to be quite normal bone tissue.

Animals ; Cleft Palate ; metabolism ; surgery ; Macaca mulatta ; Osteocalcin ; metabolism ; Osteogenesis, Distraction ; Osteopontin ; metabolism

Animals ; Bone and Bones ; metabolism ; physiology ; Endocrine System ; metabolism ; physiology ; Female ; Humans ; Male ; Osteocalcin ; metabolism

OBJECTIVETo evaluate the biological effects of nano-hydroxyapatite/polyamide 66(nHA-PA66) on the growth and activity of osteoblast.

METHODSMTT assay was used to determine the growth of osteoblast, enzymatic measure was used to determine the activity of ALP and quantitative RT-PCR (QRT-PCR) to evaluate the changes of osteoclacin mRNA expression in osteoblasts treated by DMEM eluate of nHA-PA66.

RESULTSOsteoblasts of different test groups demonstrated relative proliferation rate ranging from 98% - 106% without dose-dependent effect. The ALP activity and osteocalcin mRNA expression were similar in test and control groups (P > 0.05).

CONCLUSIONnHA-PA66 has no negative effects on the osteoblast and its osteoblast-compatibility is proved.

Durapatite ; pharmacology ; Nylons ; pharmacology ; Osteoblasts ; drug effects ; Osteocalcin ; metabolism ; RNA, Messenger ; metabolism

Bone remodeling requires a large amount of energy, and is regulated by various hormones. Leptin, produced by adipocytes, is a well-known regulator of energy balance and is also involved in controlling bone mass through interaction with the central nervous system. Serotonin, downstream of leptin, is also emerging as a candidate for controlling energy balance and bone metabolism. Currently, bone is also considered to be an endocrine regulator of energy metabolism. Osteocalcin, secreted from osteoblasts, is known to be a key regulator of glucose and fat metabolism. In this review, we describe a novel concept that asserts that there exists a biological link between bone and energy metabolism, and we summarize what is currently known about the relationship between bone and energy metabolism.
Adipocytes ; Bone Remodeling ; Central Nervous System ; Energy Metabolism* ; Glucose ; Leptin ; Metabolism ; Neurotransmitter Agents ; Osteoblasts ; Osteocalcin ; Serotonin

OBJECTIVES: To investigate the patterns of biochemical bone markers, such as urinary deoxypyridinoline (DPD), N-telopeptide of type I collagen (NTX), and serum osteocalcin (OC), bone-specific alkaline pbosphatase (BSAP) in postmenopansal women with hormone replacement therapy (HRT). Materials and METHOD: From July 1997 to January 1998, total 239 postmenopausal women were emolled in the present study, and 198 healthy premenopausal women with regular menstruation were served as control. The postmenopausal women were pouped into the HRT group and the non-HRT group. The women in the HRT poup have received estrogen with continuous or cyclic progestin therapy far more tban 6 months. The biochemical bone markers of all women were assayed. Results were analysed with Students t-test. RESULTS: The urinary DPD of the non-HRT group was sigaificantly higher than both the HRT poup and the premenopausal group(5.51 +/- 2.47 vs. 3.36 +/- 1.02 and 4.01 +/- 3.86 nM/mM, p < 0.05, repectively). The urinary NTX of the non-HRT group was also higher in comparison to the HRT group and the premenopausal group(48.71 +/- 11.54 vs. 33.70 +/- 17.43 and 33.70 +/- 17.43 nM BCE/mmol, p < 0.05, repectively). However, there were no significant differences in the concentrations of serum BSAP and OC among the three poups. CONCLUSION: The urinary DPD and NTX were more sensitive indicators of bone metabolism tban serum BSAP and OC in postmenopausal women undergoing HRT.
Collagen Type I ; Estrogens ; Female ; Hormone Replacement Therapy* ; Humans ; Menstruation ; Metabolism ; Osteocalcin

OBJECTIVE: To evaluate the effects of combined estrogen and fluocalcic therapy on the bone metabolism in the surgicalyl menopausal women with osteopenia. METHODS: This prospective randomized clinical trial examined the effects of conjugated equine estrogen and fluocalcic in combination and separately, on BMD in 200 women with low bone mass. Treatment included 0.3 mg conjugated equine estrogen (CEE) (Group I), 0.625 mg CEE (Group II), 0.3 mg CEE plus fluocalcic (Group III), and 0.625 mg CEE plus fluocalcic (Group IV) for 12 months. Biochemical markers of bone turnover were also measured every six months. RESULTS: Urinary deoxypyridinoline in Group III and Group IV decreased signifiantly at 12 months of treatment (p<0.005). Serum osteocalcin and total alkaline phosphatase decreased slightly during the treatment in all groups but statistical significance was not foundsignificantly. CONCLUSION: The combined treatment with conjugated equine estrogen and fluocalcic is more effective in surgically menopausal women with osteopenia by decreasing bone biochemical marker.
Alkaline Phosphatase ; Biomarkers ; Bone Diseases, Metabolic* ; Estrogens* ; Female ; Humans ; Metabolism* ; Osteocalcin ; Prospective Studies

OBJECTIVETo study the effects of electromagnetic pulse (EMP) on bone metabolism of mice in vivo.

METHODSTwenty-four male BALB/c mice were divided into a control group and 2 experimental groups (n=8). The whole-body of mice in experimental groups were exposed to 50 kV/m and 400kV/m EMP, 400 pulses daily for 7 consecutive days at 2 seconds intervals. Alkaline phosphotase (ALP) activity, serum calcium concentration and osteocalcin level and trabecular bone volume (BV/TV, %) were measured immediately after EMP exposure by biochemical, ELISA and morphological methods.

RESULTSThe ALP activity, serum calcium concentration and osteocalcin level and BV/TV in experimental groups remained unchanged after EMP exposure. Conclusion Under our experimental conditions, EMP exposure cannot affect bone metabolism of mice in vivo.

Alkaline Phosphatase ; Animals ; Bone and Bones ; metabolism ; Electromagnetic Fields ; Male ; Mice ; Mice, Inbred BALB C ; Osteocalcin ; blood

OBJECTIVE: To evaluate the effects of estrogen replacement therapy and pamidronate on the bone metabolism in the postmenopausal women. METHODS: This prospective randomized clinical trial examined the effects of oral pamidronate and conjugated equine estrogen, in combination and seperately, on biochemical markers of bone turnover in 140 women with low bone mass. Treatment included pamidronate (group I, n=50), or conjugated equine estrogen (group II, n=50), conjugated equine estrogen plus alendronate (group III, n=40) for 12 months. Biochemical markers of bone turnover were also measured at months 6 and 12 months. RESULTS: Serum osteocalcin and urinary deoxypyridinoline in Group I, Group II and Group III decreased signifiantly at 12 months of treatment (p<0.05). But total alkaline phosphatase decreased significantly during the treatment in Group III, but not in Group I and Group II. CONCLUSION: The combined treatment with pamidronate and conjugated equine estrogen is more effective in postmenopausal women with osteoporosis by decreasing bone biochemical markers.
Alendronate ; Alkaline Phosphatase ; Biomarkers ; Estrogen Replacement Therapy* ; Estrogens* ; Female ; Humans ; Metabolism* ; Osteocalcin ; Osteoporosis ; Postmenopause ; Prospective Studies