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Monocytes control mesenchymal stem cell differentation towards osteoblasts
S48
Abstracts / Bone 44 (2009) S18–S55
tion determined by ALP and mRNA levels of osteogenesis markers such as COL1A1 and osteocalcin. These effects were markedly enhanced in the cells from the Gαq/Gα11 DKO mice, which were restored by addition of PMA, an activator of PKC, to the levels of wildtype osteoblasts. Subcellular translocation of PKCδ to membrane enhanced by the rhPTH treatment in wild-type osteoblasts was suppressed in the DKO osteoblasts. Contrarily, cAMP accumulation in response to rhPTH was similar between cells of the two genotypes. These lines of results demonstrate the inhibitory role of the Gαq/ PKCδ signal in the bone anabolic action of PTH, suggesting that suppression of the signal may lead to a novel treatment with PTH against osteoporosis. doi:10.1016/j.bone.2009.01.122
085 Monocytes control mesenchymal stem cell differentation towards osteoblasts V. Nicolaidoua, A. Copeb, N. Horwooda Kennedy Institute of Rheumatology, London, United Kingdom Kings College London, London, United Kingdom Mesenchymal stem cells (MSC) are multipotent progenitors that can be induced in culture to form osteoblasts, adipocytes and chondrocytes. Coculturing MSC with peripheral blood mononuclear cells induced their differentiation towards osteoblasts as shown by alkaline phosphatase staining and the formation of bone nodules; this occurred in both control and osteogenic media. Purified populations of T cells, B cells and monocytes were isolated and cocultured with MSC revealing that monocytes were the cells responsible for this differentiation signal. To further dissect the monocyte population controlling differentiation, monocytes were sorted into CD14++16− and CD14+16+. The CD14+16+ monocytes, a minor population of monocytes in human peripheral blood, have been implicated in several inflammatory diseases; these cells are elevated in the both the joint and blood of rheumatoid arthritis (RA) patients. When cocultured with MSC, both populations of cells were able to induce MSC differentiation and this could be inhibited by the addition of IL-10 receptor neutralising antibodies. Interestingly, when monocytes were stimulated with LPS their activities differed greatly with the CD14++16− cells stimulating a vastly increased differentiation response whilst the CD14+16+ cells completely inhibited MSC differentiation. The CD14 ++16− population is known to produce IL-10 whilst the CD14+16+ population are the major producers of TNF and fail to make appreciable levels of IL-10. These findings have implications for the lack of bone repair in the RA joint. The presence of highly inflammatory CD14+16+ cells, combined with dysregulated cytokine production will prevent osteoblast formation whilst providing a suitable environment and precursors for excessive osteoclast formation thus exacerbating joint destruction.
in a positive bone balance, SR is known to improve intrinsic bone tissue quality. The aims of this study are (i) to evaluate whether the association of SR with PTH or Alendronate can be synergistic and able to better prevent the decrease of bone strength in OVX rats than either drug administered alone and (ii) to investigate whether its potential additive effects are dependent on the in vivo stimulation of new bone formation. OVX rats were treated with a stimulator of bone formation (PTH 8 μg/kg⁎day,SC) or a treatment decreasing bone remodeling (Alendronate 18 μg/kg twice a week,SC) with or without strontium ranelate (625 mg/kg,PO). Six groups of 12 rats (SHAM, OVX, PTH, Alendronate, SR-PTH, SR-Alendronate) received treatments or respective vehicles for 8 weeks. At the end of the experiment, vertebrae were removed for biomechanics, [micro]CT and nanoindentation testing. PTH and Alendronate prevented the deleterious effect of OVX, with PTH increasing load compared to sham. This was associated with the preservation of bone volume in Alendronate treated animals and a significant increment under PTH. Combined therapy with SR resulted in a further significant increase of maximal load as compared with PTH treated rats only. The addition of SR improved intrinsic bone tissue quality in SR-PTH treated rats and corrected the impaired intrinsic tissue quality observed under PTHtreatment. Furthermore, it resulted in a further significant increment of trabecular thickness reflecting the positive influence of SR on bone balance. No effect was observed in the case of the association with Alendronate. Together, these data suggest that strontium ranelate maximizes the in vivo effect of PTH by improving the intrinsic bone quality of the newly formed bone. The absence of synergistic effects when combined with Alendronate underlines the necessity of new bone formation.
Maximal L o a d (N) BV/T V (%) TbTh (mm) Hardness (mPa)
SHAM
OVX
PTH
Sr-PTH
Alendronate
SrAlendronate
323 ± 93#
240 ± 47
406 ± 74#
474 ± 79°#
357 ± 112#
385 ± 103#
0.337 ±0.043
0.279±0.059 0.477 ±0.054# 0.090 0.129 ± 0.002 ±0.003# 369 ± 111 335± 109
0.496 ±0.040# 0.135±0.002° # 419 ± 99°#
0.380 ±0.530# 0.100 ± 0.001# 432 ± 120#
0.398 ±0.061# 0.103 ±0.002# 422 ± 155
0.098 ± 0.001# 398 ± 82
Values are means ± SD";; significance of differences were evaluated using a Mann–Whitney test. # indicates a significant difference versus OVX and ° between PTH-SR and PTH
doi:10.1016/j.bone.2009.01.124
087 Vertebral fracture risk and alendronate effects in postmenopausal women assessed by CT-based nonlinear finite element analysis K. Imaia,b, I. Ohnishib, K. Nakamurab Sports Medicine and Orthopaedic Surgery, Toshiba General Hospital, Tokyo, Japan Orthopaedic Surgery, Tokyo University, Tokyo, Japan
doi:10.1016/j.bone.2009.01.123
086 Strontium ranelate amplifies the effects of PTH by improving the intrinsic tissue quality of the newly formed bone M. Cattani-Lorente, R. Rizzoli, A. Patrick Department of Rehabilitation and Geriatrics, Geneva University Hospital, Geneva, Switzerland Besides the effects of strontium ranelate (SR) on bone cellular activities, dissociating bone formation and resorption and resulting
CT-based nonlinear finite element analysis (FE) can accurately predict vertebral strength ex vivo. This study aimed to assess vertebral fracture risk and alendronate effects on osteoporosis in vivo using FE. Vertebral strength in 104 postmenopausal women (mean age, 71.3 years) was analyzed and the discriminatory power for vertebral fracture was assessed cross-sectionally. Alendronate effects were also prospectively assessed in 33 patients (mean age, 76.5 years) with postmenopausal osteoporosis who were treated with alendronate at a dose of 5 mg/day, compared with 8 women (mean age, 76.3 years) without any drug therapy for osteoporosis as controls. On the age and body weight adjusted logistic regression, vertebral strength by FE had stronger discriminatory power for
Abstracts / Bone 44 (2009) S18–S55
tion determined by ALP and mRNA levels of osteogenesis markers such as COL1A1 and osteocalcin. These effects were markedly enhanced in the cells from the Gαq/Gα11 DKO mice, which were restored by addition of PMA, an activator of PKC, to the levels of wildtype osteoblasts. Subcellular translocation of PKCδ to membrane enhanced by the rhPTH treatment in wild-type osteoblasts was suppressed in the DKO osteoblasts. Contrarily, cAMP accumulation in response to rhPTH was similar between cells of the two genotypes. These lines of results demonstrate the inhibitory role of the Gαq/ PKCδ signal in the bone anabolic action of PTH, suggesting that suppression of the signal may lead to a novel treatment with PTH against osteoporosis. doi:10.1016/j.bone.2009.01.122
085 Monocytes control mesenchymal stem cell differentation towards osteoblasts V. Nicolaidoua, A. Copeb, N. Horwooda Kennedy Institute of Rheumatology, London, United Kingdom Kings College London, London, United Kingdom Mesenchymal stem cells (MSC) are multipotent progenitors that can be induced in culture to form osteoblasts, adipocytes and chondrocytes. Coculturing MSC with peripheral blood mononuclear cells induced their differentiation towards osteoblasts as shown by alkaline phosphatase staining and the formation of bone nodules; this occurred in both control and osteogenic media. Purified populations of T cells, B cells and monocytes were isolated and cocultured with MSC revealing that monocytes were the cells responsible for this differentiation signal. To further dissect the monocyte population controlling differentiation, monocytes were sorted into CD14++16− and CD14+16+. The CD14+16+ monocytes, a minor population of monocytes in human peripheral blood, have been implicated in several inflammatory diseases; these cells are elevated in the both the joint and blood of rheumatoid arthritis (RA) patients. When cocultured with MSC, both populations of cells were able to induce MSC differentiation and this could be inhibited by the addition of IL-10 receptor neutralising antibodies. Interestingly, when monocytes were stimulated with LPS their activities differed greatly with the CD14++16− cells stimulating a vastly increased differentiation response whilst the CD14+16+ cells completely inhibited MSC differentiation. The CD14 ++16− population is known to produce IL-10 whilst the CD14+16+ population are the major producers of TNF and fail to make appreciable levels of IL-10. These findings have implications for the lack of bone repair in the RA joint. The presence of highly inflammatory CD14+16+ cells, combined with dysregulated cytokine production will prevent osteoblast formation whilst providing a suitable environment and precursors for excessive osteoclast formation thus exacerbating joint destruction.
in a positive bone balance, SR is known to improve intrinsic bone tissue quality. The aims of this study are (i) to evaluate whether the association of SR with PTH or Alendronate can be synergistic and able to better prevent the decrease of bone strength in OVX rats than either drug administered alone and (ii) to investigate whether its potential additive effects are dependent on the in vivo stimulation of new bone formation. OVX rats were treated with a stimulator of bone formation (PTH 8 μg/kg⁎day,SC) or a treatment decreasing bone remodeling (Alendronate 18 μg/kg twice a week,SC) with or without strontium ranelate (625 mg/kg,PO). Six groups of 12 rats (SHAM, OVX, PTH, Alendronate, SR-PTH, SR-Alendronate) received treatments or respective vehicles for 8 weeks. At the end of the experiment, vertebrae were removed for biomechanics, [micro]CT and nanoindentation testing. PTH and Alendronate prevented the deleterious effect of OVX, with PTH increasing load compared to sham. This was associated with the preservation of bone volume in Alendronate treated animals and a significant increment under PTH. Combined therapy with SR resulted in a further significant increase of maximal load as compared with PTH treated rats only. The addition of SR improved intrinsic bone tissue quality in SR-PTH treated rats and corrected the impaired intrinsic tissue quality observed under PTHtreatment. Furthermore, it resulted in a further significant increment of trabecular thickness reflecting the positive influence of SR on bone balance. No effect was observed in the case of the association with Alendronate. Together, these data suggest that strontium ranelate maximizes the in vivo effect of PTH by improving the intrinsic bone quality of the newly formed bone. The absence of synergistic effects when combined with Alendronate underlines the necessity of new bone formation.
Maximal L o a d (N) BV/T V (%) TbTh (mm) Hardness (mPa)
SHAM
OVX
PTH
Sr-PTH
Alendronate
SrAlendronate
323 ± 93#
240 ± 47
406 ± 74#
474 ± 79°#
357 ± 112#
385 ± 103#
0.337 ±0.043
0.279±0.059 0.477 ±0.054# 0.090 0.129 ± 0.002 ±0.003# 369 ± 111 335± 109
0.496 ±0.040# 0.135±0.002° # 419 ± 99°#
0.380 ±0.530# 0.100 ± 0.001# 432 ± 120#
0.398 ±0.061# 0.103 ±0.002# 422 ± 155
0.098 ± 0.001# 398 ± 82
Values are means ± SD";; significance of differences were evaluated using a Mann–Whitney test. # indicates a significant difference versus OVX and ° between PTH-SR and PTH
doi:10.1016/j.bone.2009.01.124
087 Vertebral fracture risk and alendronate effects in postmenopausal women assessed by CT-based nonlinear finite element analysis K. Imaia,b, I. Ohnishib, K. Nakamurab Sports Medicine and Orthopaedic Surgery, Toshiba General Hospital, Tokyo, Japan Orthopaedic Surgery, Tokyo University, Tokyo, Japan
doi:10.1016/j.bone.2009.01.123
086 Strontium ranelate amplifies the effects of PTH by improving the intrinsic tissue quality of the newly formed bone M. Cattani-Lorente, R. Rizzoli, A. Patrick Department of Rehabilitation and Geriatrics, Geneva University Hospital, Geneva, Switzerland Besides the effects of strontium ranelate (SR) on bone cellular activities, dissociating bone formation and resorption and resulting
CT-based nonlinear finite element analysis (FE) can accurately predict vertebral strength ex vivo. This study aimed to assess vertebral fracture risk and alendronate effects on osteoporosis in vivo using FE. Vertebral strength in 104 postmenopausal women (mean age, 71.3 years) was analyzed and the discriminatory power for vertebral fracture was assessed cross-sectionally. Alendronate effects were also prospectively assessed in 33 patients (mean age, 76.5 years) with postmenopausal osteoporosis who were treated with alendronate at a dose of 5 mg/day, compared with 8 women (mean age, 76.3 years) without any drug therapy for osteoporosis as controls. On the age and body weight adjusted logistic regression, vertebral strength by FE had stronger discriminatory power for