MMP-2, MMP-9 and their inhibitors TIMP-2 and TIMP-1 production by human monocytes in vitro in the presence of different forms of hydroxyapatite particles.

DOI : 10.1016/j.biomaterials.2003.09.034After calcium-phosphates biomaterials based implantation like hydroxyapatite (HA) coating, particles are released in the periprosthetic tissues. Wear-debris induced fibrous membranes contain macrophage subsets that can produce metalloproteinases (MMPs), which are considered to be key enzymes in extra-cellular matrix turnover. Tissue inhibitors of metalloproteinases (TIMPs) are important regulator of MMPs activity. Interleukin-1 mainly produced by monocytes can also regulate MMPs production. In the present work, we have evaluated the effect of HA particles characteristics (size, shape and sintering temperature) on the MMP-2, -9 and their respective inhibitors TIMP-2, -1 production. Our results demonstrate that sintering temperature (that modify crystal size and surface area) have little effect on MMPs and TIMPs production. Non-phagocytable particles induced more MMP-9, although phagocytable particles induced more IL-1β release. The shape of the particles was the most important factor since needle-shaped particles induced the most significant up-regulated expression of MMPs and IL-1β

STEM and EDXS characterisation of physico-chemical reactions at the periphery of sol-gel derived Zn-substituted hydroxyapatites during interactions with biological fluids

With its good properties of biocompatibility and bioactivity hydroxyapatite (HA) is highly used as bone substitutes and as coatings on metallic prostheses. In order to improve bioactive properties of HA we have elaborated Zn2+ doped hydroxyapatite. Zn2+ ions substitute for Ca2+ cations in the HA structure and four Zn concentrations (Zn/Zn+Ca) were prepared 0.5, 1, 2, 5 % at. To study physico-chemical reactions at the materials periphery, we immersed the bioceramics into biological fluids for delays from 1 day to 20 days. The surface changes were studied at the nanometer scale by scanning transmission electron microscopy associated to energy dispersive X-ray spectroscopy. After 20 days of immersion we observed the formation of a calcium-phosphate layer at the periphery of the HA doped with 5% of zinc. This layer contains magnesium and its thickness was around 200 nm. Formation of this Ca-P-Mg layer represents bioactivity properties of the 5% Zn-substituted hydroxyapatite. This biologically active layer improves properties of HA and will permit a chemical bond between the ceramic and bone

Mécanismes de régulation de la production de cytokines pro-inflammatoires (TNF-a,IL-6,IL-)8 et IL-18 et anti-inflammatoire (IL-10) : modèle du kératinocyte humain irradié par des UVB/Alexia Grandjean

Les @kératinocytes participent à la défense immunitaire de l'organisme en synthétisant de nombreuses cytokines. Nous avons étudié au cours de ce travail les mécanismes de régulation de la synthèse de cytokines pro-inflammatoires (TNF-a, IL-6, IL-8 et IL-18) et anti-inflammatoire (IL-10) dans des cultures de kératinocytes irradiés par un rayonnement UVB. Nous avons observé une augmentation dose-dépendante de l'expression des cytokines en fonction de la dose d'UVB appliquée. Nous avons ensuite cherché à définir l'implication des facteurs de transcription NF-kB et AP-1 dans la régulation de la synthèse de cytokines en utilisant la curcumine et le PDTC. En présence de curcumine, nous observons une inhibition de l'activation du facteur NF-kB et de la synthèse des cytokines inflammatoires. A l'opposé, l'expression de l'IL-10 est augmentée. En revanche, l'activation du facteur AP-1 n'est pas affectée par la curcumine. En présence de PDTC, nous observons une inhibition de l'activation du facteur NF-kB ainsi qu'une augmentation de l'activation du facteur AP-1 ; ainsi qu'une inhibition de l'expression du TNF-a et de l'IL-6 et une activation de l'IL-8 et de l'IL-10. Ces résultats suggèrent une régulation du TNF-a et de l'IL-6 NF-kB dépendante, et de l'IL-8 NF-kB et AP-1 dépendante. Puis nous avons étudié la voie de la PKA. Pour cela nous avons traité des kératinocytes irradiés avec: 1) dbAMPc, PGE2 et toxine cholérique (agents qui augmentent l'AMPc intracellulaire) et, 2) H89 et PKAi (inhibiteurs spécifiques). Nous observons, en présence des analogues de l'AMPc, une inhibition de l'expression du TNF-a et de l'IL-18 ainsi qu'une augmentation de l'IL-6 et de l'IL-10. Le traitement par les inhibiteurs de la PKA a pour conséquence une inhibition de la synthèse des quatre cytokines étudiées. Ces résultats montrent que la régulation des cytokines produites lors de l'irradiation des kératinocytes fait intervenir des voies de signalisation différentes selon la cytokine étudiée.REIMS-BU Santé (514542104) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Importance of the surface area ratio (SAR) and particles shape on cytokines production by human monocytes in vitro induced by various hydroxyapatite particles. Importance de la surface de contact (cellules-particules d'hydroxyapatite) et de la forme des particules sur la production de cytokines libérées par des monocytes humains en culture.

Une complication possible consécutive à l'implatation de prothèses à base d'hydroxyapatite (HA) est la libération de particules d'usure étant susceptibles d'induire une réaction inflammatoire sur le site d'implantation après phagocytose de ces particules par des monocytes. Il a été précédemment montré qu'en utilisant un rapport surfacique de 1 pour 1 (surface particules-surface cellules) certaines particules d'HA induisaient l'expression et la production de cytokines impliquées lors d'une réaction inflammatoire. Dans cette présente étude, nous avons étudié l'effet d'un rapport surfacique de 10 pour 1 sur la synthèse de cytokines (TNF-a, IL-6, IL-8 et IL-10) produites par des monocytes humains en réponse à des particules d'HA de différentes formes. Nous avons mis en évidence que l'expression des cytokines augmentait avec le rapport surfacique alors que la production était régulée et ce, semble-t-il, de façon post-transcriptionnelle

The effect of the physical characteristics of hydroxyapatite particles on human monocytes IL-18 production in vitro.

Hydroxyapatite (HA) is widely used to coat the metal parts of prosthetic implants in order to improve their biocompatibility and as a bone defect filling material. HA has been demonstrated to produce particles at the prosthetic interface that lead to an activation of phagocytic cells that induce a cascade reaction leading to bone resorption and aseptic loosening. Monocytes/macrophages are commonly observed in the interface tissue, and are among the first cells to colonize the inflammatory site where they play a key role in the immune response. IL-18 is a pro-inflammatory cytokine. Monocytes/macrophages were described as IL-18 producing cells. IL-18 works antagonistically to IL-6, which activates osteoclastogenesis. In the present study, we investigated the ability of HA particles to induce the production of active IL-18 by human monocytes according to particle characteristics (size, sintering temperature and shape). Our study demonstrates, for the first time, that HA particles are capable of stimulating the production of the proinflammatory cytokine IL-18 in human monocytes according to their particle characteristics. The expression and the production of IL-18 was modified by the parameter studied. The difference observed between the expression and the production could be explain by the production of ICE. The needle shaped particles induced the larger production of IL-18

Influence des propriétés physicochimiques d'hydroxyapatites sur le comportement cellulaire. Effect of the physicochemical characteristics of hydroxyapatite on the cell behaviour.

soumis à ITBMLes biocéramiques phosphocalciques sont utilisées comme substitut osseux depuis de nombreuses décennies. Le descellement aseptique après une arthroplastir totale est un problème majeur en chirurgie orthopédique. Les particules d'hydroxyapatite issues du biomatériau ont été identifiées comme cause majeure de l'échec de l'implantation. Pour cette raison et afin d'augmenter la longévité des implants aprés une arthroplastie, des recherches dans le domaine de ces particules relarguées sont donc nécessaires. Dans cet article, nous discutons de la réponse cellulaire (principalement des monocytes/macrophages qui sont parmi les premières cellules à coloniser le site inflammatoire) après exposition à des particules ayant des caractéristiques différentes (taille, forme, température de traitement et composition chimique). Les caractéristiques les plus importantes sont d'abord la forme puis la taille des particules. En effets, les particules sous forme d'aiguille induisent une plus grande production de médiateurs de l'inflammation et elles sont plus toxiques pour les cellules. La température de traitement semble être moins importante même si elle joue un rôle important dans les processus de dissolution/précipitation. Peu de choses sont connues sur l'effet d'ions dopant l'hydroxyapatite (comme le zinc, le strontium,...) sur la réponse cellulaire. Les premières données montrent que le dopage semble bénéfique pour les cellules

Characterization of Intra-Cellular Ionic Concentrations of Monocytes in Contact with Bioactive Glasses and Hydroxyapatite Particles. A TEM Cryo-X-ray Analysis of Diffusible Ions

A cells viability can be altered by the presence of bioactive materials particles and their features. This paper compares the influence of hydroxyapatite particles and bioactive glass particles on intracellular ionic concentrations of the monocytes exposed to them. However, microanalysis of intracellular ions like sodium, potassium, and chlorine is a major problem. In order to limit diffusion phenomenon and to preserve the chemical identity of specimens, we used cryomethods (cryo-preparation, and cryo-x-ray microanalysis to study cells in contact with bioactive materials particles. We measured intracellular ionic concentrations by scanning transmission electron microsccopy (STEM) associated with energy dispersive x-ray spectroscopy (EDXS). Monocytes were exposed to bioactive glass particles and to hydroxyapatite particles during 2 days. The K/Na ratio was used as a sensitive criteria of viability of cells

Importance of the surface area ratio on cytokines production by human monocytes in vitro induced by various hydroxyapatite particles.

A possible complication associated with the implantation of hydroxyapatite (HA)-based prosthesis is the release of particles. Those particles can be phagocyted by monocytes that are among the first cells to colonize the inflammatory site. The activated monocytes produce inflammatory mediators, such as cytokines, which cause osteoclasts activation. It has previously been demonstrated using a surface area ratio (ratio of the total surface of the given particles to the surface area of cells) of 1 to 1 that there was a correlation between the expression and production of cytokines induced by HA. The present work studies the effect of physical characteristics of HA particles on the production of various inflammatory cytokines (tumour necrosis factor-alpha, interleukin (IL)-6, and IL-8) and anti-inflammatory cytokine (IL-10). However, the experiments were performed using a surface area ratio of 10 to 1. Our data demonstrate that all the particles, whatever their characteristics, induced a high expression of cytokines but the production was different, meaning that there was a post-transcriptional regulation. The size and sintering temperature seemed to be a characteristics that were less important compared to the shape; the needle particles appeared to induce the most important production of all the cytokines studied

Autovaccination against tumors using a mineral/protein composite

In this Chapter we describe the use of a mineral to purify heat shock proteins to be used, in conjunction with the mineral compound, as autovaccine in cancer patients.Fil: Frayssinet, P.. No especifíca;Fil: Cuello Carrión, Fernando Darío. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Laquerriere, Patricia. Inserm; FranciaFil: Grandjean Laquerriere, Alexia. Inserm; FranciaFil: Ciocca, Daniel Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Correlation between sintering temperature of hydroxyapatite particles and the production of inflammatory cytokines by human monocytes

Osteolysis remains the most important problem in orthopaedic implant failure. Wear debris from the implant contains hydroxyapatite particles which have show to activate monocyte cells. Although the response of monoccytes has been observed to be influenced by size and shape of the hydroxyapatite particles, little is known on the effect of surface properties on inflammatory cytokines production. In this study, human monocytes have been exposed to hydroxyapatite particles sintered at different temperatures (not sintered, sintered at 600 and 1180°C. We show that the sintering temperature modifies the crystal size and the pH of zero charge of the particles. Moreover, interleukin 1-beta, tumor necrosis factor-alpha and interleukin-6 secretion were evaluated as a function of the sintering temperature because they play a key role in the osteoclast cells differentiation. The level of secretion was small compared to the production induced by zymosan particles. But we demonstrate in the present paper that the particles sintered at the highest temperature induced the most important production of the cytokines studied