Aseptic loosening is the most critical problem in total hip arthroplasty. It can occur in even a ... more Aseptic loosening is the most critical problem in total hip arthroplasty. It can occur in even a technically well-inserted prosthesis. Although many reports have been published on the pathogenesis of loosening, the precise mechanism of loosening has not been elucidated 1,2. In animal models proinflammatory cytokines have been proposed to have an important role 3. However, this has not been proved in human tissue. The current study was designed to determine the cellular the cytokine and chemokine network from periprosthetic tissues of loose hips joints and from synovium in hips with osteoarthritis. Materials and Methods. Interface tissues between bone and prosthesis were collected from 15 cases of aseptic loose artificial hip joint at revision. Synovial tissue samples were collected from 14 patients with hip osteoarthritis at primary surgery Table I. The samples were retrieved fresh, using a sterile technique, and immediately were placed in stabilizing solution (RNA later, QIAGEN) and stored at-20 0 C. Total RNA was isolated (Trizol) and the quality was confirmed by aragose gel electrophoresis. Real-time RT-PCR was carried out using iQ TM SYBR ® green supermix reagent (Bio-RAD, CA), and mRNA amounts were normalized relative to control gene HPRT. Generation of only the correct amplification products confirmed by melting curve analysis of the products. The Mann-Whitney test was applied to detect significant differences in the expression levels for each mRNA between the two groups. Results. Relative mRNA expression levels, fold increase or decrease in osteolysis patients compared to controls, and p values are shown in Table II. Osteoclastogenesis. Osteoclast markers (Cath K, TRAP, MMP9, DC-STAMP) were significantly higher in osteolysis patients. Osteoprotegerin was low in osteolysis while RANKL was not significantly different in two groups. Macrophage activation. There was no difference in levels of the pro-inflammatory cytokines TNFa and IL-6. However, the alternative macrophage activation markers chitinase and CCL18 were 66 and 3 fold more in osteolysis, respectively. BCL2A1, an antiapoptotic macrophage protein was 16 fold more abundant in osteolysis patients. Chemokines. IL-8 and MIP1A were significant higher in osteolysis Osteogenesis. BMP4 and FGF18 were significantly lower in osteolysis patients than controls. Discussion The data from this in vivo study show that proinflammatory cytokines are not expressed at significantly elevated levels in end stage osteolysis patients. Proinflammatory cytokines signaling is prominently involved in animal models of osteolysis, and may be involved in the early stages of osteolysis. However, our data showed a different pathogenesis during the chronic stage of osteolysis. Rather, an alternative activation of macrophages characterized by increased levels of markers as Chit-1, CCL18 and BCL2A1 is evident. Elevated expression of chemokines and decreased OPG (but unchanged RANKL expression) contributes to the increased osteoclastogenesis associated with this disease. In addition, this study shows an impairment of osteoblastic bone formation indicated by decreased BMP4 and FGF18
The ability of prosthetic wear debris to induce pro-inflammatory responses in macrophages is wide... more The ability of prosthetic wear debris to induce pro-inflammatory responses in macrophages is widely appreciated, but little is known about the molecular mechanisms involved in particle recognition. Specifically, the nature of the cell surface receptors that interact with wear debris is poorly understood. Elucidating the identities of these receptors and how they interact with different types of wear debris are critical to understanding how wear debris initiates periprosthetic osteolysis. We examined the involvement of opsonization, complement receptor 3 (CR3), and scavenger receptor A (SRA), in responses to polymethylmethacrylate (PMMA) and titanium wear particles. Serum dependence of pro-inflammatory responses to PMMA and titanium was tested, and serum proteins that adhered to these two types of particles were identified. Several serum proteins, including known opsonins such as C3bi and fibronectin, adhered to PMMA but not titanium, and serum was required for pro-inflammatory signaling induced by PMMA, but not by titanium. Phagocytosis of PMMA and titanium by macrophages was demonstrated by flow cytometry. Blocking CR3 specifically inhibited phagocytosis of PMMA by macrophages, whereas blocking SRA specifically inhibited titanium uptake. Direct involvement of CR3 and SRA in cell-particle interaction was assessed by expression of these receptors in nonphagocytic HEK293 cells. CR3 specifically induced cell binding to PMMA particles and adhesion to PMMA-coated plates, while SRA specifically induced binding to titanium particles and adhesion to titanium-coated plates. Taken together, these results suggest involvement of opsonization, complement, and integrin receptors, including CR3 and fibronectin receptors, in PMMA action, and an involvement of scavenger receptors in responses to titanium.
Background: Wear debris challenge of macrophages provokes the generation of proinflammatory cytok... more Background: Wear debris challenge of macrophages provokes the generation of proinflammatory cytokines, which contribute to periprosthetic osteolysis. However, it is not known whether this effect is accompanied by reprogramming of other cytokines present within the periprosthetic tissue that may be involved in anti-osteoclastogenic activities. In the present study, we examined the ability of wear debris particles to inhibit the signaling of two such cytokines, interleukin-6 and interferon-γ. Methods: Human osteoclast precursor cells were challenged with particles of titanium or polymethylmethacrylate bone cement prior to the addition of the cytokines interleukin-6 or interferon-γ. Interleukin-6 signaling was determined by measuring the activation of STAT3 signal transduction with use of immunoblotting and electrophoretic mobility shift assays. Interferon-γ signaling was determined by measuring the activation of STAT1 with use of immunoblotting and electrophoretic mobility shift assays and by measuring the expression of interferon-γ-inducible genes with use of realtime reverse transcription-polymerase chain reaction assays. Involvement of mitogen-activated protein kinases in cytokine signaling was assessed by including mitogen-activated protein kinase inhibitors in these assays and also by means of immunoblot assessment of mitogen-activated protein kinase activation by wear debris particles. Wear debris modulation of expression of the cytokine suppressors SOCS1 and SOCS3 (as well as pro-inflammatory mediators) was assessed with use of real-time reverse transcription-polymerase chain reaction assays. Results: Both titanium and polymethylmethacrylate particles potently inhibited interleukin-6-induced STAT3 activation in human osteoclast precursor cells. Inhibition of p38 mitogen-activated protein kinase, which is activated by titanium and polymethylmethacrylate, reversed the inhibitory effects of these particles on interleukin-6 signaling, whereas inhibition of ERK and JNK mitogen-activated protein kinases (which are also activated by both types of wear debris) had no effect. Titanium and polymethylmethacrylate also both induced expression of SOCS3, an inhibitor of interleukin-6 signaling. In addition to its effects on interleukin-6 signaling, titanium also profoundly inhibited the interferon-γinduced activation of STAT1 and the expression of interferon-γ-inducible genes, whereas polymethylmethacrylate had no effect on interferon-γ signaling. Conclusions: Titanium inhibits both interferon-γ and interleukin-6 signaling in human osteoclast precursor cells, whereas polymethylmethacrylate bone cement inhibits only the latter. Wear particle inhibition of interleukin-6 specifically involves the activation of p38 mitogen-activated protein kinase and is accompanied by substantial induction of SOCS3, an inhibitor of interleukin-6 signaling. In contrast, titanium inhibition of interferon-γ signaling is not dependent on mitogen-activated protein kinase activation and is accompanied by only modest induction of the interferon-γ inhibitor SOCS1. Clinical Relevance: The critical role of wear debris in the development of periprosthetic osteolysis likely involves the inhibition of anti-inflammatory/anti-osteoclastogenic cytokine signaling in addition to the well-established induction of pro-inflammatory mediators. Strategies to augment these "protective" signaling pathways may therefore have therapeutic potential for the treatment of periprosthetic osteolysis.
... Titre du document / Document title. SYNTHESIS OF 7-AMINO-4,5,6,7-TETRAHYDROTHIENO-3,4-CPYRID-... more ... Titre du document / Document title. SYNTHESIS OF 7-AMINO-4,5,6,7-TETRAHYDROTHIENO-3,4-CPYRID-4-ONES. Auteur(s) / Author(s). LAN PHAM KHANH ; DALLEMAGNE P. ; ALSAIDI A. ; RAULT S. ; Revue / Journal Title. Heterocycles ISSN 0385-5414 CODEN HTCYAM ...
The American Journal of Tropical Medicine and Hygiene, 2012
We previously reported a new community-based mosquito control strategy that resulted in eliminati... more We previously reported a new community-based mosquito control strategy that resulted in elimination of Aedes aegypti (Linn.
Aseptic loosening is the most critical problem in total hip arthroplasty. It can occur in even a ... more Aseptic loosening is the most critical problem in total hip arthroplasty. It can occur in even a technically well-inserted prosthesis. Although many reports have been published on the pathogenesis of loosening, the precise mechanism of loosening has not been elucidated 1,2. In animal models proinflammatory cytokines have been proposed to have an important role 3. However, this has not been proved in human tissue. The current study was designed to determine the cellular the cytokine and chemokine network from periprosthetic tissues of loose hips joints and from synovium in hips with osteoarthritis. Materials and Methods. Interface tissues between bone and prosthesis were collected from 15 cases of aseptic loose artificial hip joint at revision. Synovial tissue samples were collected from 14 patients with hip osteoarthritis at primary surgery Table I. The samples were retrieved fresh, using a sterile technique, and immediately were placed in stabilizing solution (RNA later, QIAGEN) and stored at-20 0 C. Total RNA was isolated (Trizol) and the quality was confirmed by aragose gel electrophoresis. Real-time RT-PCR was carried out using iQ TM SYBR ® green supermix reagent (Bio-RAD, CA), and mRNA amounts were normalized relative to control gene HPRT. Generation of only the correct amplification products confirmed by melting curve analysis of the products. The Mann-Whitney test was applied to detect significant differences in the expression levels for each mRNA between the two groups. Results. Relative mRNA expression levels, fold increase or decrease in osteolysis patients compared to controls, and p values are shown in Table II. Osteoclastogenesis. Osteoclast markers (Cath K, TRAP, MMP9, DC-STAMP) were significantly higher in osteolysis patients. Osteoprotegerin was low in osteolysis while RANKL was not significantly different in two groups. Macrophage activation. There was no difference in levels of the pro-inflammatory cytokines TNFa and IL-6. However, the alternative macrophage activation markers chitinase and CCL18 were 66 and 3 fold more in osteolysis, respectively. BCL2A1, an antiapoptotic macrophage protein was 16 fold more abundant in osteolysis patients. Chemokines. IL-8 and MIP1A were significant higher in osteolysis Osteogenesis. BMP4 and FGF18 were significantly lower in osteolysis patients than controls. Discussion The data from this in vivo study show that proinflammatory cytokines are not expressed at significantly elevated levels in end stage osteolysis patients. Proinflammatory cytokines signaling is prominently involved in animal models of osteolysis, and may be involved in the early stages of osteolysis. However, our data showed a different pathogenesis during the chronic stage of osteolysis. Rather, an alternative activation of macrophages characterized by increased levels of markers as Chit-1, CCL18 and BCL2A1 is evident. Elevated expression of chemokines and decreased OPG (but unchanged RANKL expression) contributes to the increased osteoclastogenesis associated with this disease. In addition, this study shows an impairment of osteoblastic bone formation indicated by decreased BMP4 and FGF18
The ability of prosthetic wear debris to induce pro-inflammatory responses in macrophages is wide... more The ability of prosthetic wear debris to induce pro-inflammatory responses in macrophages is widely appreciated, but little is known about the molecular mechanisms involved in particle recognition. Specifically, the nature of the cell surface receptors that interact with wear debris is poorly understood. Elucidating the identities of these receptors and how they interact with different types of wear debris are critical to understanding how wear debris initiates periprosthetic osteolysis. We examined the involvement of opsonization, complement receptor 3 (CR3), and scavenger receptor A (SRA), in responses to polymethylmethacrylate (PMMA) and titanium wear particles. Serum dependence of pro-inflammatory responses to PMMA and titanium was tested, and serum proteins that adhered to these two types of particles were identified. Several serum proteins, including known opsonins such as C3bi and fibronectin, adhered to PMMA but not titanium, and serum was required for pro-inflammatory signaling induced by PMMA, but not by titanium. Phagocytosis of PMMA and titanium by macrophages was demonstrated by flow cytometry. Blocking CR3 specifically inhibited phagocytosis of PMMA by macrophages, whereas blocking SRA specifically inhibited titanium uptake. Direct involvement of CR3 and SRA in cell-particle interaction was assessed by expression of these receptors in nonphagocytic HEK293 cells. CR3 specifically induced cell binding to PMMA particles and adhesion to PMMA-coated plates, while SRA specifically induced binding to titanium particles and adhesion to titanium-coated plates. Taken together, these results suggest involvement of opsonization, complement, and integrin receptors, including CR3 and fibronectin receptors, in PMMA action, and an involvement of scavenger receptors in responses to titanium.
Background: Wear debris challenge of macrophages provokes the generation of proinflammatory cytok... more Background: Wear debris challenge of macrophages provokes the generation of proinflammatory cytokines, which contribute to periprosthetic osteolysis. However, it is not known whether this effect is accompanied by reprogramming of other cytokines present within the periprosthetic tissue that may be involved in anti-osteoclastogenic activities. In the present study, we examined the ability of wear debris particles to inhibit the signaling of two such cytokines, interleukin-6 and interferon-γ. Methods: Human osteoclast precursor cells were challenged with particles of titanium or polymethylmethacrylate bone cement prior to the addition of the cytokines interleukin-6 or interferon-γ. Interleukin-6 signaling was determined by measuring the activation of STAT3 signal transduction with use of immunoblotting and electrophoretic mobility shift assays. Interferon-γ signaling was determined by measuring the activation of STAT1 with use of immunoblotting and electrophoretic mobility shift assays and by measuring the expression of interferon-γ-inducible genes with use of realtime reverse transcription-polymerase chain reaction assays. Involvement of mitogen-activated protein kinases in cytokine signaling was assessed by including mitogen-activated protein kinase inhibitors in these assays and also by means of immunoblot assessment of mitogen-activated protein kinase activation by wear debris particles. Wear debris modulation of expression of the cytokine suppressors SOCS1 and SOCS3 (as well as pro-inflammatory mediators) was assessed with use of real-time reverse transcription-polymerase chain reaction assays. Results: Both titanium and polymethylmethacrylate particles potently inhibited interleukin-6-induced STAT3 activation in human osteoclast precursor cells. Inhibition of p38 mitogen-activated protein kinase, which is activated by titanium and polymethylmethacrylate, reversed the inhibitory effects of these particles on interleukin-6 signaling, whereas inhibition of ERK and JNK mitogen-activated protein kinases (which are also activated by both types of wear debris) had no effect. Titanium and polymethylmethacrylate also both induced expression of SOCS3, an inhibitor of interleukin-6 signaling. In addition to its effects on interleukin-6 signaling, titanium also profoundly inhibited the interferon-γinduced activation of STAT1 and the expression of interferon-γ-inducible genes, whereas polymethylmethacrylate had no effect on interferon-γ signaling. Conclusions: Titanium inhibits both interferon-γ and interleukin-6 signaling in human osteoclast precursor cells, whereas polymethylmethacrylate bone cement inhibits only the latter. Wear particle inhibition of interleukin-6 specifically involves the activation of p38 mitogen-activated protein kinase and is accompanied by substantial induction of SOCS3, an inhibitor of interleukin-6 signaling. In contrast, titanium inhibition of interferon-γ signaling is not dependent on mitogen-activated protein kinase activation and is accompanied by only modest induction of the interferon-γ inhibitor SOCS1. Clinical Relevance: The critical role of wear debris in the development of periprosthetic osteolysis likely involves the inhibition of anti-inflammatory/anti-osteoclastogenic cytokine signaling in addition to the well-established induction of pro-inflammatory mediators. Strategies to augment these "protective" signaling pathways may therefore have therapeutic potential for the treatment of periprosthetic osteolysis.
... Titre du document / Document title. SYNTHESIS OF 7-AMINO-4,5,6,7-TETRAHYDROTHIENO-3,4-CPYRID-... more ... Titre du document / Document title. SYNTHESIS OF 7-AMINO-4,5,6,7-TETRAHYDROTHIENO-3,4-CPYRID-4-ONES. Auteur(s) / Author(s). LAN PHAM KHANH ; DALLEMAGNE P. ; ALSAIDI A. ; RAULT S. ; Revue / Journal Title. Heterocycles ISSN 0385-5414 CODEN HTCYAM ...
The American Journal of Tropical Medicine and Hygiene, 2012
We previously reported a new community-based mosquito control strategy that resulted in eliminati... more We previously reported a new community-based mosquito control strategy that resulted in elimination of Aedes aegypti (Linn.
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