Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Evaluation of the contribution of marine hemoglobin in cell culture and in the cellularization of bone and meniscal substitutes by mesenchymal stem cells

Ce travail de thèse avait pour objectif le développement de systèmes de culture cellulaire, en 2D et en 3D, en mettant à profit les propriétés d’un transporteur d’oxygène marin, HEMOXCell®. Notre approche générale était articulée selon deux grands axes : un premier concernant l’évaluation de l’utilisation d’HEMOXCell® dans la culture de deux modèles cellulaires, et un second, utilisant les résultats obtenus à des fins d’ingénierie tissulaire. Dans le premier axe, l’évaluation de l’effet dose-réponse d’HEMOXCell® dans la culture des cellules CHO-S et des cellules souches mésenchymateuses (CSM), a permis de déterminer des concentrations de travail optimales, favorisant la viabilité et la prolifération cellulaire. Le modèle cellulaire CHO-S a contribué à la mise en place d’un test de performance de la molécule, et encouragé son utilisation dans des systèmes de bioproduction. Les essais menés sur les CSM ont quant à eux permis de valider l’innocuité de la molécule à de faibles doses et le maintien de l’état « souche ». L’idée d’associer les CSM à des supports poreux est prometteuse pour des applications d’ingénierie tissulaire, mais est soumise aux problèmes liés à l’oxygénation en profondeur des supports. Dans le second axe de ce projet, nous avons oeuvré à améliorer la colonisation de substituts osseux et méniscaux, en culture statique et dynamique, en présence d’HEMOXCell®. Parallèlement, une étude a été menée pour tenter de caractériser les cellules méniscales. Les analyses de la colonisation des biomatériaux suggèrent un effet bénéfique d’HEMOXCell® lorsqu’il est utilisé en complément des milieux de différenciation cellulaire. Ce travail a contribué à améliorer la compréhension de ce transporteur d’oxygène et à l’élargissement de ses potentiels champs d’utilisation notamment dans un cadre thérapeutique.This work aimed to develop cell culture systems, in 2D and 3D, based on the properties of HEMOXCell®, a marine oxygen carrier. Our approach was articulated in two main parts: the first one dealing with the assessment of the use of HEMOXCell® in the culture of two cellular models, and the second one, exploiting the results obtained for tissue engineering purposes. In this first axis, the dose-response effect of HEMOXCell® in the CHO-S cells and mesenchymal stem cells (MSC) in vitro culture, allowed the identification of optimal working concentrations, which can promote cell viability and proliferation. The CHO-S model has contributed to the establishment of a performance test of the molecule, and encouraged its use for bioproduction stimulation. The tests performed on MSCs were used to validate the harmlessness of the molecule at low doses and the maintenance of "stemness". The idea to associate MSCs with porous scaffolds is a promising approach for tissue engineering applications, but it is confronted to the lack of oxygen in the depth of the substitutes. In the second part of this project, we worked at improving the cellularization of bone and meniscal substitutes, under static and dynamic culture systems, w/ and w/o HEMOXCell®. In parallel, a study was conducted to attempt to characterize the meniscal cells. Analyses of cellularized biomaterials suggest a beneficial effect of HEMOXCell® when used as a differentiation media supplement. This work contributed to improve this oxygen carrier understanding and to extend the field of its potential uses particularly for therapeutic applications

Evaluation de la contribution d'une hémoglobine marine dans la culture cellulaire et dans la cellularisation de substituts osseux et méniscaux par des cellules souches mésenchymateuses

This work aimed to develop cell culture systems, in 2D and 3D, based on the properties of HEMOXCell®, a marine oxygen carrier. Our approach was articulated in two main parts: the first one dealing with the assessment of the use of HEMOXCell® in the culture of two cellular models, and the second one, exploiting the results obtained for tissue engineering purposes. In this first axis, the dose-response effect of HEMOXCell® in the CHO-S cells and mesenchymal stem cells (MSC) in vitro culture, allowed the identification of optimal working concentrations, which can promote cell viability and proliferation. The CHO-S model has contributed to the establishment of a performance test of the molecule, and encouraged its use for bioproduction stimulation. The tests performed on MSCs were used to validate the harmlessness of the molecule at low doses and the maintenance of "stemness". The idea to associate MSCs with porous scaffolds is a promising approach for tissue engineering applications, but it is confronted to the lack of oxygen in the depth of the substitutes. In the second part of this project, we worked at improving the cellularization of bone and meniscal substitutes, under static and dynamic culture systems, w/ and w/o HEMOXCell®. In parallel, a study was conducted to attempt to characterize the meniscal cells. Analyses of cellularized biomaterials suggest a beneficial effect of HEMOXCell® when used as a differentiation media supplement. This work contributed to improve this oxygen carrier understanding and to extend the field of its potential uses particularly for therapeutic applications.Ce travail de thèse avait pour objectif le développement de systèmes de culture cellulaire, en 2D et en 3D, en mettant à profit les propriétés d’un transporteur d’oxygène marin, HEMOXCell®. Notre approche générale était articulée selon deux grands axes : un premier concernant l’évaluation de l’utilisation d’HEMOXCell® dans la culture de deux modèles cellulaires, et un second, utilisant les résultats obtenus à des fins d’ingénierie tissulaire. Dans le premier axe, l’évaluation de l’effet dose-réponse d’HEMOXCell® dans la culture des cellules CHO-S et des cellules souches mésenchymateuses (CSM), a permis de déterminer des concentrations de travail optimales, favorisant la viabilité et la prolifération cellulaire. Le modèle cellulaire CHO-S a contribué à la mise en place d’un test de performance de la molécule, et encouragé son utilisation dans des systèmes de bioproduction. Les essais menés sur les CSM ont quant à eux permis de valider l’innocuité de la molécule à de faibles doses et le maintien de l’état « souche ». L’idée d’associer les CSM à des supports poreux est prometteuse pour des applications d’ingénierie tissulaire, mais est soumise aux problèmes liés à l’oxygénation en profondeur des supports. Dans le second axe de ce projet, nous avons oeuvré à améliorer la colonisation de substituts osseux et méniscaux, en culture statique et dynamique, en présence d’HEMOXCell®. Parallèlement, une étude a été menée pour tenter de caractériser les cellules méniscales. Les analyses de la colonisation des biomatériaux suggèrent un effet bénéfique d’HEMOXCell® lorsqu’il est utilisé en complément des milieux de différenciation cellulaire. Ce travail a contribué à améliorer la compréhension de ce transporteur d’oxygène et à l’élargissement de ses potentiels champs d’utilisation notamment dans un cadre thérapeutique

New Triazacycloalkane Derivatives as Cytotoxic Agents for CLL Treatment: From Proof of Concept to the Targeting Biomolecule

International audienceThe 1,4,7-tris-(2-pyridinylmethyl)-1,4,7-triazacyclononane ligand (no3py) and its bifunctional analogue no3pyCOOK were synthesized to investigate their action toward zinc(II) depletion related to the apoptosis phenomenon in chronic lymphocytic leukemia (CLL) cells. no3py was used as the “free” ligand, while its “graftable” derivative was conjugated on a newly synthesized bifunctional sialoglycan, 6′-SL-NH2, selected to specifically bind CD22 biomarker expressed on the B-CLL cell surface. Both compounds were produced with good yields thanks to a Sonogashira coupling reaction and an orthoester function, respectively, for the chelator and the targeting moiety. The newly reported bioconjugate 6′-SL-no3py was then obtained through a peptidic coupling reaction. Biological in vitro studies of no3py and 6′-SL-no3py consisting of real-time detection of cell health (cytotoxicity and proliferation) and caspases 3/7 activation (crucial enzymes whose activation triggers cell death signaling pathways) have been investigated. First, Ramos, Daudi, and Raji B-cell lines, which present different sensitivity to zinc(II) content variation, were incubated with no3py and 6′-SL-no3py. Then, a videomicroscope allowed the real-time monitoring of the morphological changes leading to cell death from the detection of the cytotoxicity, the antiproliferative effect, and the caspasic activity. In terms of mechanism, the Zn2+ chelator cytotoxic effect of no3py has been evidenced by a culture medium ion supplementation study and by the decrease of intracellular fluorescence of Zn-specific fluorophore zinquin in the presence of no3py and 6′-SL-no3py chelators. Finally, flow cytometry analysis with classical Annexin V staining was conducted to detect no3py- and 6′-SL-no3py-induced apoptotic cell death in B-CLL cells. Time-course analysis, using the Incucyte Live-Cell Analysis System, demonstrated that no3py induced cell death in a time- and dose-dependent manner with variability across cell lines. 6′-SL-no3py exhibited the same dose-dependent trend as no3py, showing the efficiency of the targeting moiety. In both cases, the chelators depicted proliferation curves that were inversely correlated with kinetic death. Morphological changes specific to apoptosis and caspase 3/7 activation were observed for the three cell lines treated with no3py and 6′-SL-no3py, highlighting their role as apoptotic agents. A higher concentration of 6′-SL-no3py is needed to reach 50% of the B-CLL mortality, confirming a targeting of the chelator to the cell membrane. Overall, our results proved that the biological properties of the triazamacrocyclic chelator still remain even after addition of the targeting moiety. The free chelator as well as the bioconjugate constitute promising cytotoxic agents for CLL therapy through apoptosis induction

Adhesion, proliferation and osteogenic differentiation of human MSCs cultured under perfusion with a marine oxygen carrier on an allogenic bone substitute

International audienceTissue engineering strategies have been developed to optimize osseointegration in dental implant surgery. One of the major problems is the non-homogeneous spatial cell distribution in the scaffold, as well as subsequent matrix production. Insufficient nutrient and oxygen supplies inside the scaffold are factors in this phenomenon. To mediate this gradient formation, we have implemented a perfusion culture method to seed human bone marrow mesenchymal stem cells (MSCs) into three-dimensional (3-D)-allogenic bone scaffolds in combination with a marine haemoglobin, HEMOXCell®, for oxygen delivery. Cell culture was performed under static and perfusion conditions, with standard and osteogenic media, with and without HEMOXCell®. The cell seeding efficiency, as well as MSC/scaffold cytocompatibly were assessed using viability and proliferation assays. Scaffolds' cellularization and extracellular matrix (ECM) formation were analyzed using scanning electron microscopy and histological staining. Cell differentiation was investigated with osteogenic biomarkers gene expression analysis. The perfusion culture was observed to significantly promote MSC proliferation and differentiation throughout the scaffolds, especially when using the induction medium w/HEMOXCell®. Our data suggest that perfusion culture of MSC into allogenic bone substitute with HEMOXCell® as a natural oxygen carrier is promising for tissue engineering applications to oxygenate hypoxic areas and to promote cellular proliferation

Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial

Background Reoperation rates are high after surgery for hip fractures. We investigated the effect of a sliding hip screw versus cancellous screws on the risk of reoperation and other key outcomes. Methods For this international, multicentre, allocation concealed randomised controlled trial, we enrolled patients aged 50 years or older with a low-energy hip fracture requiring fracture fixation from 81 clinical centres in eight countries. Patients were assigned by minimisation with a centralised computer system to receive a single large-diameter screw with a side-plate (sliding hip screw) or the present standard of care, multiple small-diameter cancellous screws. Surgeons and patients were not blinded but the data analyst, while doing the analyses, remained blinded to treatment groups. The primary outcome was hip reoperation within 24 months after initial surgery to promote fracture healing, relieve pain, treat infection, or improve function. Analyses followed the intention-to-treat principle. This study was registered with ClinicalTrials.gov, number NCT00761813. Findings Between Mar

Opportunistic infections and AIDS malignancies early after initiating combination antiretroviral therapy in high-income countries

Background: There is little information on the incidence of AIDS-defining events which have been reported in the literature to be associated with immune reconstitution inflammatory syndrome (IRIS) after combined antiretroviral therapy (cART) initiation. These events include tuberculosis, mycobacterium avium complex (MAC), cytomegalovirus (CMV) retinitis, progressive multifocal leukoencephalopathy (PML), herpes simplex virus (HSV), Kaposi sarcoma, non-Hodgkin lymphoma (NHL), cryptococcosis and candidiasis. Methods: We identified individuals in the HIV-CAUSAL Collaboration, which includes data from six European countries and the US, who were HIV-positive between 1996 and 2013, antiretroviral therapy naive, aged at least 18 years, hadCD4+ cell count and HIV-RNA measurements and had been AIDS-free for at least 1 month between those measurements and the start of follow-up. For each AIDS-defining event, we estimated the hazard ratio for no cART versus less than 3 and at least 3 months since cART initiation, adjusting for time-varying CD4+ cell count and HIV-RNA via inverse probability weighting. Results: Out of 96 562 eligible individuals (78% men) with median (interquantile range) follow-up of 31 [13,65] months, 55 144 initiated cART. The number of cases varied between 898 for tuberculosis and 113 for PML. Compared with non-cART initiation, the hazard ratio (95% confidence intervals) up to 3 months after cART initiation were 1.21 (0.90-1.63) for tuberculosis, 2.61 (1.05-6.49) for MAC, 1.17 (0.34-4.08) for CMV retinitis, 1.18 (0.62-2.26) for PML, 1.21 (0.83-1.75) for HSV, 1.18 (0.87-1.58) for Kaposi sarcoma, 1.56 (0.82-2.95) for NHL, 1.11 (0.56-2.18) for cryptococcosis and 0.77 (0.40-1.49) for candidiasis. Conclusion: With the potential exception of mycobacterial infections, unmasking IRIS does not appear to be a common complication of cART initiation in high-income countries