Short-course thymoglobulin induction and steroid-free immunosuppressive regimen in renal transplantation

Purpose: Optimal induction and maintenance immunosuppressive therapies in renal transplantation are still a matter of debate.Chronic corticosteroid usage is a major cause of morbidity but steroid-free immunosuppression (SF) can result in unacceptably high rates of acute rejection and even graft loss. Methods and materials: We have conducted a prospective openlabelled clinical trial in the Geneva-Lausanne Transplant Network from March 2005 to May 2008. 20 low immunological risk (<20% PRA, no DSA) adult recipients of a primary kidney allograft received a 4-day course of thymoglobulin (1.5 mg/kg/d) with methylprednisolone and maintenance based immunosuppression of tacrolimus and entericcoated mycophenolic acid (MPA). The control arm consisted of 16 matched recipients treated with basiliximab induction, tacrolimus, mycophenolate mofetil and corticosteroids. Primary endpoints were the percentage of recipients not taking steroids and the percentage of rejection-free recipients at 12 months.Secondary end points were allograft survival at 12 months and significant thymoglobulin and/or other drugs side effects. Results: In the SF group, 85% of the kidney recipients remained steroid-free at 12 months. The 3 cases of steroids introduction were due to one acute tubulo-interstitial rejection occurring at day 11, one tacrolimus withdrawal due to thrombotic microangiopathy and one MPA withdrawal because of multiple sinusitis and CMV reactivations. No BK viremia was detected nor CMV disease. The 6 CMV negative patients who received a positive CMV allograft had a symptomatic primoinfection after their 6-month course valgancyclovir prophylaxis. In the steroid-based group, 3 acute rejection episodes (acute humoral rejection, acute tubulointerstitial Banff IA and vascular Banff IIA) occurred in 2 recipients, 3 BK virus nephropathies were diagnosed between 45 and 135 days post transplant No side effects were associated with thymoglobulin infusion.In the SF group, 4 recipients presented severe leukopenia or agranulocytosis and one recipient had febrile hepatitis leading to transient MPA withdrawal. Discontinuation of MPA was needed in 2 patients for recurrent sinusitis and CMV reactivations. Patient and graft survival was 100% in both groups at 12 month follow-up. Conclusion: Steroid-free with short-course thymoglobulin induction therapy was a safe protocol in low-risk renal transplant recipients. Lower rates of acute rejection and BK virus infections episodes were seen compared to the steroid-based control group. A longer follow-up will be needed to determine whether this SF immunosuppressive regimen will result in higher graft and patient survival.

Desenvolupament de vacunes peptídiques y dendrímers basats en polietilenglicol per al tractament del càncer

El principal problema de les teràpies actuals contra el càncer es la baixa especificitat envers les cèl•lules tumorals, cosa que comporta gran quantitat d’efectes secundaris. Per això es important el desenvolupament de nous tipus de teràpies i sistemes d’alliberament efectius per als fàrmacs ja existents al mercat. En la immunoteràpia contra el càncer es pretén estimular el sistema immunològic per a eliminar les cèl•lules canceroses de manera selectiva. En aquest projecte s’han sintetitzat derivats de l’antigen peptídic de melanoma NY-ESO1 i s’ha estudiat la seva capacitat per a estimular el sistema immunològic com a vacunes contra el càncer. També s’han encapsulat el antígens peptídics en liposomes com a adjuvants i sistemes d’alliberament. De totes les variants peptídiques la que resultà més immunogènica fou la que contenia el grup palmitoil i el fragment toxoide tetànic en la seva estructura. La utilització de liposomes com a sistema adjuvant sembla una estratègia interessant per al disseny de vacunes contra el càncer donat que l’encapsulació del pèptid en liposomes va augmentar notablement la resposta immunològica de l’antigen. Per altra banda, s’han desenvolupat dendrímers basats en polietilenglicol com a sistemes alliberadors de fàrmacs per al tractament de tumors. El polietilenglicol és àmpliament utilitzat com a sistema d’alliberament de fàrmacs degut a les seves interessants propietats, augment de la solubilitat i dels temps de residència en plasma, entre d’altres. La metodologia química descrita permet la diferenciació controlada de varies posicions en la superfície del dendrímer a més del creixement del dendrímer fins a una segona generació. S’ha sintetitzat la primera generació del dendrímer contenint el fàrmac antitumoral 5-fluorouracil i s’han realitzat estudis de citotoxicitat comprovant que l’activitat del nanoconjugat és del mateix ordre de magnitud que el 5-fluorouracil sense conjugar.

Self-identity and religion/spirituality

Although medicine is practised in a secular setting, religious and spiritual issues have an impact on patient perspectives regarding their health and the management of any disorders that may afflict them. This is especially true in psychiatry, as feelings of spirituality and religiousness are very prevalent among the mentally ill. Clinicians are rarely aware of the importance of religion and understand little of its value as a mediating force for coping with mental illness. This book addresses various issues concerning mental illness in psychiatry: the relation of religious issues to mental health; the tension between a theoretical approach to problems and psychiatric approaches; the importance of addressing these varying approaches in patient care and how to do so; and differing ways to approach Christian, Muslim, and Buddhist patients. This is the first book to specifically cover the impact of religion and spirituality on mental illness.

Normal glucagon signaling and β-cell function after near-total α-cell ablation in adult mice.

OBJECTIVEEvaluate whether healthy or diabetic adult mice can tolerate an extreme loss of pancreatic α-cells and how this sudden massive depletion affects β-cell function and blood glucose homeostasis.RESEARCH DESIGN AND METHODSWe generated a new transgenic model allowing near-total α-cell removal specifically in adult mice. Massive α-cell ablation was triggered in normally grown and healthy adult animals upon diphtheria toxin (DT) administration. The metabolic status of these mice was assessed in 1) physiologic conditions, 2) a situation requiring glucagon action, and 3) after β-cell loss.RESULTSAdult transgenic mice enduring extreme (98%) α-cell removal remained healthy and did not display major defects in insulin counter-regulatory response. We observed that 2% of the normal α-cell mass produced enough glucagon to ensure near-normal glucagonemia. β-Cell function and blood glucose homeostasis remained unaltered after α-cell loss, indicating that direct local intraislet signaling between α- and β-cells is dispensable. Escaping α-cells increased their glucagon content during subsequent months, but there was no significant α-cell regeneration. Near-total α-cell ablation did not prevent hyperglycemia in mice having also undergone massive β-cell loss, indicating that a minimal amount of α-cells can still guarantee normal glucagon signaling in diabetic conditions.CONCLUSIONSAn extremely low amount of α-cells is sufficient to prevent a major counter-regulatory deregulation, both under physiologic and diabetic conditions. We previously reported that α-cells reprogram to insulin production after extreme β-cell loss and now conjecture that the low α-cell requirement could be exploited in future diabetic therapies aimed at regenerating β-cells by reprogramming adult α-cells.

Ophtalmologie. Rétinopathie diabétique: nouvelles possibilités thérapeutiques [Diabetic retinopathy: new therapeutic possibilities].

La rétinopathie diabétique touche un nombre croissant de personnes, soit quatre millions en Europe, ce chiffre va probablement doubler d'ici 2030. Si l'on considère que 25-30% de ces patients sont atteints de rétinopathie diabétique, un dépistage et un traitement précoce permettent d'éviter les complications oculaires sévères telles que l'oedème maculaire cystoïde où la rétinopathie diabétique proliférative. Un résumé des dernières données de la littérature ophtalmologique est présenté en insistant sur le rôle de l'anti-VEGF (vascular endothelial growth factor) et des implants intravitréens de corticostéroïdes pour une pathologie oculaire récemment classée dans les pathologies inflammatoires. Diabetic retinopathy affects an increasing number of persons, about 4 millions in Europe, a number that will probably double until 2030. If we consider that 25-30% of patients are affected by diabetic retinopathy, an ophthalmologic screening and early therapy will allow a better visual prognosis and avoid severe ocular complications such as diabetic macular edema and proliferative diabetic retinopathy. A summary of current ophthalmologic literature was performed and was focused on the role of anti-VEGF (vascular endothelial growth factor) therapies and intraocular drug delivery of corticosteroids in a pathology that was recently classified in inflammatory pathologies.

Endothelial cell integrins and COX-2: mediators and therapeutic targets of tumor angiogenesis.

Vascular integrins are essential regulators and mediators of physiological and pathological angiogenesis, including tumor angiogenesis. Integrins provide the physical interaction with the extracellular matrix (ECM) necessary for cell adhesion, migration and positioning, and induce signaling events essential for cell survival, proliferation and differentiation. Integrins preferentially expressed on neovascular endothelial cells, such as alphaVbeta3 and alpha5beta1, are considered as relevant targets for anti-angiogenic therapies. Anti-integrin antibodies and small molecular integrin inhibitors suppress angiogenesis and tumor progression in many animal models, and are currently tested in clinical trials as anti-angiogenic agents. Cyclooxygense-2 (COX-2), a key enzyme in the synthesis of prostaglandins and thromboxans, is highly up-regulated in tumor cells, stromal cells and angiogenic endothelial cells during tumor progression. Recent experiments have demonstrated that COX-2 promotes tumor angiogenesis. Chronic intake of nonsteroidal anti-inflammatory drugs and COX-2 inhibitors significantly reduces the risk of cancer development, and this effect may be due, at least in part, to the inhibition of tumor angiogenesis. Endothelial cell COX-2 promotes integrin alphaVbeta3-mediated endothelial cell adhesion, spreading, migration and angiogenesis through the prostaglandin-cAMP-PKA-dependent activation of the small GTPase Rac. In this article, we review the role of integrins and COX-2 in angiogenesis, their cross talk, and discuss implications relevant to their targeting to suppress tumor angiogenesis.

Producing on-line ultrapure dialysis fluid.

The process of on-line generation of ultrapure dialysis fluid is a core prerequisite for the safe execution of modern renal replacement therapies such as on-line hemodiafiltration and high-flux hemodialysis. In these extracorporeal treatments with variable degrees of convection, significant volumes of plasma water are removed and replaced with dialysis fluid, which must occur without causing harm to the patient. Historically, on-line generation of sterile and pyrogen-free physiological substitution fluid by the process of membrane ultrafiltration of fresh dialysis fluid has its origin in hemofiltration, a purely convective therapy. Development of this and later therapies is described in the historical context of a successful effort over decades to overcome the above formidable challenge, which was provided jointly by pioneering clinical investigators and a resourceful dialysis industry.

Optimum in vitro expansion of human antigen-specific CD8 T cells for adoptive transfer therapy.

Increasing evidence suggests that adoptive transfer of antigen-specific CD8(+) T cells could represent an effective strategy in the fight against chronic viral infections and malignancies such as melanoma. None the less, a major limitation in the implementation of such therapy resides in the difficulties associated with achieving rapid and efficient expansion of functional T cells in culture necessary to obtain the large numbers required for intravenous infusion. Recently, the critical role of the cytokines interleukin (IL)-2, IL-7 and IL-15 in driving T cell proliferation has been emphasized, thus suggesting their use in the optimization of expansion protocols. We have used major histocompatibility complex (MHC) class I/peptide multimers to monitor the expansion of antigen-specific CD8 T lymphocytes from whole blood, exploring the effect of antigenic peptide dose, IL-2, IL-7 and IL-15 concentrations on the magnitude and functional characteristics of the antigen-specific CD8(+) T cells generated. We show here that significant expansions of antigen-specific T cells, up to 50% of the CD8(+) T cell population, can be obtained after a single round of antigen/cytokine (IL-2 or IL-15) stimulation, and that these cells display good cytolytic and interferon (IFN)-gamma secretion capabilities. Our results provide an important basis for the rapid in vitro expansion of autologous T cells from the circulating lymphocyte pool using a simple procedure, which is necessary for the development of adoptive transfer therapies.

Immunological mechanism of action and clinical profile of disease-modifying treatments in multiple sclerosis.

Multiple sclerosis (MS) is a life-long, potentially debilitating disease of the central nervous system (CNS). MS is considered to be an immune-mediated disease, and the presence of autoreactive peripheral lymphocytes in CNS compartments is believed to be critical in the process of demyelination and tissue damage in MS. Although MS is not currently a curable disease, several disease-modifying therapies (DMTs) are now available, or are in development. These DMTs are all thought to primarily suppress autoimmune activity within the CNS. Each therapy has its own mechanism of action (MoA) and, as a consequence, each has a different efficacy and safety profile. Neurologists can now select therapies on a more individual, patient-tailored basis, with the aim of maximizing potential for long-term efficacy without interruptions in treatment. The MoA and clinical profile of MS therapies are important considerations when making that choice or when switching therapies due to suboptimal disease response. This article therefore reviews the known and putative immunological MoAs alongside a summary of the clinical profile of therapies approved for relapsing forms of MS, and those in late-stage development, based on published data from pivotal randomized, controlled trials.

Changing Religiosity, Changing Politics? The Influence of 'Belonging' and 'Believing' on Political Attitudes in Switzerland

Starting from theories of secularization and of religious individualization, we propose a two-dimensional typology of religiosity and test its impact on political attitudes. Unlike classic conceptions of religiosity used in political studies, our typology simultaneously accounts for an individual's sense of belonging to the church (institutional dimension) and his/her personal religious beliefs (spiritual dimension). Our analysis, based on data from the World Values Survey in Switzerland (1989-2007), shows two main results. First, next to evidence of religious decline, we also find evidence of religious change with an increase in the number of people who "believe without belonging." Second, non-religious individuals and individuals who believe without belonging are significantly more permissive on issues of cultural liberalism than followers of institutionalized forms of religiosity.

Importance of influx and efflux systems and xenobiotic metabolizing enzymes in intratumoral disposition of anticancer agents.

In this review, intratumoral drug disposition will be integrated into the wide range of resistance mechanisms to anticancer agents with particular emphasis on targeted protein kinase inhibitors. Six rules will be established: 1. There is a high variability of extracellular/intracellular drug level ratios; 2. There are three main systems involved in intratumoral drug disposition that are composed of SLC, ABC and XME enzymes; 3. There is a synergistic interplay between these three systems; 4. In cancer subclones, there is a strong genomic instability that leads to a highly variable expression of SLC, ABC or XME enzymes; 5. Tumor-expressed metabolizing enzymes play a role in tumor-specific ADME and cell survival and 6. These three systems are involved in the appearance of resistance (transient event) or in the resistance itself. In addition, this article will investigate whether the overexpression of some ABC and XME systems in cancer cells is just a random consequence of DNA/chromosomal instability, hypo- or hypermethylation and microRNA deregulation, or a more organized modification induced by transposable elements. Experiments will also have to establish if these tumor-expressed enzymes participate in cell metabolism or in tumor-specific ADME or if they are only markers of clonal evolution and genomic deregulation. Eventually, the review will underline that the fate of anticancer agents in cancer cells should be more thoroughly investigated from drug discovery to clinical studies. Indeed, inhibition of tumor expressed metabolizing enzymes could strongly increase drug disposition, specifically in the target cells resulting in more efficient therapies.

IL-5 and IL-5 receptor in asthma

Eosinophils, along with mast cells are key cells involved in the innate immune response against parasitic infection whereas the adaptive immune response is largely dependent on lymphocytes. In chronic parasitic disease and in chronic allergic disease, IL-5 is predominantly a T cell derived cytokine which is particularly important for the terminal differentiation, activation and survival of committed eosinophil precursors. The human IL-5 gene is located on chromosome 5 in a gene cluster that contains the evolutionary related IL-4 family of cytokine genes. The human IL-5 receptor complex is a heterodimer consisting of a unique a subunit (predominantly expressed on eosinophils) and a beta subunit which is shared between the receptors for IL-3 & GM-CSF (more widely expressed). The a subunit is required for ligand-specific binding whereas association with the beta subunit results in increased binding affinity. The alternative splicing of the alphaIL-5R gene which contains 14 exons can yield several alphaIL-5R isoforms including a membrane-anchored isoform (alphaIL-5Rm) and a soluble isoform (alphaIL-5Rs). Cytokines such as IL-5 produce specific and non-specific cellular responses through specific cell membrane receptor mediated activation of intracellular signal transduction pathways which, to a large part, regulate gene expression. The major intracellular signal transduction mechanism is activation of non-receptor associated tyrosine kinases including JAK and MAP kinases which can then transduce signals via a novel family of transcriptional factors named signal transducers and activators of transcription (STATS). JAK2, STAT1 and STAT 5 appear to be particularly important in IL-5 mediated eosinophil responses. Asthma is characterized by episodic airways obstruction, increased bronchial responsiveness, and airway inflammation. Several studies have shown an association between the number of activated T cells and eosinophils in the airways and abnormalities in FEV1, airway reactivity and clinical severity in asthma. It has now been well documented that IL-5 is highly expressed in the bronchial mucosa of atopic and intrinsic asthmatics and that the increased IL-5 mRNA present in airway tissues is predominantly T cell derived. Immunocytochemical staining of bronchial biopsy sections has confirmed that IL-5 mRNA transcripts are translated into protein in asthmatic subjects. Furthermore, the number of activated CD 4 + T cells and IL-5 mRNA positive cells are increased in asthmatic airways following antigen challenge and studies that have examined IL-5 expression in asthmatic subjects before and after steroids have shown significantly decreased expression following oral corticosteroid treatment in steroid-sensitive asthma but not in steroid resistant and chronic severe steroid dependent asthma. The link between T cell derived IL-5 and eosinophil activation in asthmatic airways is further strengthened by the demonstration that there is an increased number of alphaIL-5R mRNA positive cells in the bronchial biopsies of atopic and non-atopic asthmatic subjects and that the eosinophil is the predominant site of this increased alphaIL-5R mRNA expression. We have also shown that the subset of activated eosinophils that expressed mRNA for membrane bound alpha IL5r inversely correlated with FEV1, whereas the subset of activated eosinophils that expressed mRNA for soluble alphaIL5r directly correlated with FEV1. Hence, not only does this data suggest that the presence of eosinophils expressing alphaIL-5R mRNA contribute towards the pathogenesis of bronchial asthma, but also that the eosinophil phenotype with respect to alphaIL-5R isoform expression is of central importance. Finally, there are several animal, and more recently in vitro lung explant, models of allergen induced eosinophilia, late airway responses(LARS), and bronchial hyperresponsiveness(BHR) - all of which support a link between IL-5 and airway eosinophila and bronchial hyperresponsiveness. The most direct demonstration of T cell involvement in LARS is the finding that these physiological responses can be transferred by CD4+ but not CD8+ T cells in rats. The importance of IL-5 in animal models of allergen induced bronchial hyperresponsiveness has been further demonstrated by a number of studies which have indicated that IL-5 administration is able to induce late phase responses and BHR and that anti-IL-5 antibody can block allergen induced late phase responses and BHR. In summary, activated T lymphocytes, IL5 production and eosinophil activation are particularly important in the asthmatic response. Human studies in asthma and studies in allergic animal models have clearly emphasised the unique role of IL-5 in linking T lymphocytes and adaptive immunity, the eosinophil effector cell, and the asthma phenotype. The central role of activated lymphocytes and eosinophils in asthma would argue for the likely therapeutic success of strategies to block T cell and eosinophil activation (eg steroids). Importantly, more targeted therapies may avoid the complications associated with steroids. Such therapies could target key T cell activation proteins and cytokines by various means including blocking antibodies (eg anti-CD4, anti-CD40, anti-IL-5 etc), antisense oligonucleotides to their specific mRNAs, and/or selective inhibition of the promoter sites for these genes. Another option would be to target key eosinophil activation mechanisms including the aIL5r. As always, the risk to benefit ratio of such strategies await the results of well conducted clinical trials.

Microtubule-depolymerizing agents used in antibody-drug conjugates induce antitumor immunity by stimulation of dendritic cells.

Antibody-drug conjugates (ADC) are emerging as powerful treatment strategies with outstanding target-specificity and high therapeutic activity in patients with cancer. Brentuximab vedotin represents a first-in-class ADC directed against CD30(+) malignancies. We hypothesized that its sustained clinical responses could be related to the stimulation of an anticancer immune response. In this study, we demonstrate that the dolastatin family of microtubule inhibitors, from which the cytotoxic component of brentuximab vedotin is derived, comprises potent inducers of phenotypic and functional dendritic cell (DC) maturation. In addition to the direct cytotoxic effect on tumor cells, dolastatins efficiently promoted antigen uptake and migration of tumor-resident DCs to the tumor-draining lymph nodes. Exposure of murine and human DCs to dolastatins significantly increased their capacity to prime T cells. Underlining the requirement of an intact host immune system for the full therapeutic benefit of dolastatins, the antitumor effect was far less pronounced in immunocompromised mice. We observed substantial therapeutic synergies when combining dolastatins with tumor antigen-specific vaccination or blockade of the PD-1-PD-L1 and CTLA-4 coinhibitory pathways. Ultimately, treatment with ADCs using dolastatins induces DC homing and activates cellular antitumor immune responses in patients. Our data reveal a novel mechanism of action for dolastatins and provide a strong rationale for clinical treatment regimens combining dolastatin-based therapies, such as brentuximab vedotin, with immune-based therapies. Cancer Immunol Res; 2(8); 741-55. ©2014 AACR.

Experimental approaches in the targeting of photodynamic therapeutics

RÉSUMÉ : Chez l'homme, le manque de sélectivité des agents thérapeutiques représente souvent une limitation pour le traitement des maladies. Le ciblage de ces agents pour un tissu défini pourrait augmenter leur sélectivité et ainsi diminuer les effets secondaires en comparaison d'agents qui s'accumuleraient dans tout le corps. Cela pourrait aussi améliorer l'efficacité des traitements en permettant d'avoir une concentration localisée plus importante. Le ciblage d'agents thérapeutiques est un champ de recherche très actif. Les stratégies sont généralement basées sur les différences entre cellules normales et malades. Ces différences peuvent porter soit sur l'expression des molécules à leurs surfaces comme des récepteurs ou des transporteurs, soit sur les activités enzymatiques exprimées. Le traitement thérapeutique choisi ici est la thérapie photodynamique et est déjà utilisé pour le traitement de certains cancers. Cette thérapie repose sur l'utilisation de molécules qui réagissent à la lumière, les photosensibilisants. Elles absorbent l'énergie lumineuse et réagissent avec l'oxygène pour former des radicaux toxiques pour les cellules. Les photosensibilisants utilisés ici sont de deux natures : (i) soit ils sont tétrapyroliques (comme les porphyrines et chlorines), c'est à dire qu'ils sont directement activables par la lumière ; (ii) soit ce sont des prodrogues de photosensibilisants comme l'acide 5aminolévulinique (ALA) qui est transformé dans la cellule en protoporphyrine IX photosensibilisante. Dans le but d'augmenter la sélectivité des photosensibilisants, nous avons utilisé deux stratégies différentes : (i) le photosensibilisant est modifié par le greffage d'un agent de ciblage ; (ii) le photosensibilisant est incorporé dans des structures moléculaires de quelques centaines de nanomètres. Les sucres et l'acide folique sont des agents de ciblage largement établis et ont été utilisés ici car leurs récepteurs sont surexprimés à la surface de nombreuses cellules malades. Ainsi, des dérivés sucres ou acide folique de l'ALA ont été synthétisés et évalués in vitro sur de nombreuses lignées cellulaires cancéreuses. La stratégie utilisant l'acide folique est apparue incompatible avec l'utilisation de l'ALA puisque aucune photosensibilité n'a été induite par le composé. La stratégie utilisant les sucres a, par ailleurs, provoquée de bonnes photosensibilités mais pas d'augmentation de sélectivité. En parallèle, la combinaison entre les propriétés anticancéreuses des complexes métalliques au ruthénium avec les propriétés photosensibilisantes des porphyrines, a été évaluée. En effet, les thérapies combinées ont émergé il y a une dizaine d'années et représentent aujourd'hui de bonnes alternatives aux monothérapies classiques. Des ruthenium(I1)-arènes complexés avec la tetrapyridylporphyrine ont ainsi présenté de bonnes cytotoxicités et de bonnes phototoxicités pour des cellules de mélanomes. Des porphyrines ont aussi été compléxées avec des noyaux de diruthénium et ce type de dérivé a présenté de bonnes phototoxicités et une bonne sélectivité pour les cellules cancéreuses de l'appareil reproducteur féminin. L'incorporation de photosensibilisants tétrapyroliques a finalement été effectuée en utilisant des nanoparticules (NP) biocompatibles composées de chitosan et de hyaluronate. L'effet de ces NP a été évalué pour le traitement de la polyarthrite rhumatoïde (PR). Les NP ont d'abord été testées in vitro avec des macrophages de souris et les résultats ont mis en évidence de bonnes sélectivités et photosensibilités pour ces cellules. In vivo chez un modèle marin de la PR, l'utilisation de ces NP a révélé un plus grand temps de résidence des NP dans le genou de la souris en comparaison du temps obtenu avec le photosensibilisant seul. Le traitement par PDT a aussi démontré une bonne efficacité par ailleurs égale à celle obtenue avec les corticoïdes utilisés en clinique. Pour finir, les NP ont aussi démontré une bonne efficacité sur les myelomonocytes phagocytaires humains et sur les cellules contenues dans le liquide synovial de patients présentant une PR. Tous ces résultats suggèrent que les deux stratégies de ciblage peuvent être efficaces pour les agents thérapeutiques. Afm d'obtenir de bons résultats, il est toutefois nécessaire de réaliser une analyse minutieuse de la cible et du mode d'action de l'agent thérapeutique. Concernant les perspectives, la combinaison des deux stratégies c'est à dire incorporer des agents thérapeutiques dans des nanostructures porteuses d'agents de ciblage, représente probablement une solution très prometteuse. SUMMARY : In humans, the lack of selectivity of drugs and their high effective concentrations often represent limitations for the treatment of diseases. Targeting the therapeutical agents to a defined tissue could enhance their selectivity and then diminish their side effects when compared to drugs that accumulate in the entire body and could also improve treatment efûciency by allowing a localized high concentration of the agents. Targeting therapeutics to defined cells in human pathologies is a main challenge and a very active field of research. Strategies are generally based on the different behaviors and patterns of expression of diseased cells compared to normal cells such as receptors, proteases or trans-membrane carriers. The therapeutic treatment chosen here is the photodynamic therapy and is already used in the treatment of many cancers. This therapy relies on the administration of a photosensitizer (PS) which will under light, react with oxygen and induce formation of reactive oxygen species which are toxic for cells. The PSs used here are either tetrapyrolic (i. e. porphyries and chlorins) or prodrugs of PS (5-aminolevulinic acid precursor of the endogenous protoporphyrin Imo. In order to improve PS internalization and selectivity, we have used two different strategies: the modification of the PSs with diseased cell-targeting agents as well as their encapsulation into nanostructures. Sugars and folic acid are well established as targeting entities for diseased cells and were used here since their transporters are overexpressed on the surface of many cancer cells. Therefore sugar- and folic acid-derivatives of 5-aminolevulinic acid (ALA) were synthesized and evaluated in vitro in several cancer cell lines. The folic acid strategy appeared to be incompatible with ALA since no photosensitivity was induced while the strategy with sugars induced good photosensitivites but no increase of selectivity. Alternatively, the feasibility of combining the antineoplastic properties of ruthenium complexes with the porphyrin's photosensitizing properties, was evaluated since combined therapies have emerged as good alternatives to classical treatments. Tetrapyridylporphyrins complexed to ruthenium (I17 arenes presented good cytotoxicities and good phototoxicities toward melanoma cells. Porphyries were also complexed to diruthenium cores and this type of compound presented good phototoxicities and good selectivity for female reproductive cancer cells. The encapsulation of tetrapyrolic PSs was finally investigated using biocompatible nanogels composed of chitosan and hyaluronate. The behavior of these nanoparticles was evaluated for the treatment of rheumatoid arthritis (RA). They were first tested in vitro in mouse macrophages and results revealed good selectivities and phototoxicities toward these cells. In vivo in mice model of RA, the use of such nanoparticles instead of free PS showed longer time of residence in mice knees. Photodynamic protocols also demonstrated good efficiency of the treatment comparable to the corticoid injection used in the clinic. Finally our system was also efficient in human cells using phagocytic myelomonocytes or using cells of synovial fluids taken from patients with RA. Altogether, these results revealed that both strategies of modification or encapsulation of drugs can be successful in the targeting of diseased cells. However, a careful analysis of the target and of the mode of action of the drug, are needed in order to obtain good results. Looking ahead to the future, the combination of the two strategies (i.e. drugs loaded into nanostructures bearing the targeting agents) would represent probably the best solution.

« L'esthétique du chant dans la piété calviniste aux premiers temps de la Réforme (1536-1545) »

Contrairement aux idées reçues, l'esthétique assume bien une fonction dans les formes rituelles adoptées par les Eglises issues de la Réforme calviniste. Mais il revient moins à l'image, considérée avant tout comme une source de distraction, qu'à la musique de porter cette dimension dans la piété réformée. Retraçant la formation de la pensée calvinienne sur la question des rapports entre culte et musique entre 1536 et 1543, cette étude montre comment le théologien en vient durant ces années à considérer que le chant des psaumes permet de concilier dans la dévotion, un processus cognitif, guidé par le sens des paroles, et un mouvement affectif, suscité par la mélodie. C'est, aux yeux de Calvin, de la jonction de ces deux dynamiques que naît l'élévation spirituelle à laquelle le culte doit conduire. Notwithstanding common belief, aesthetics had an important function in ritual forms implemented by Reformed Calvinist Churches. The impact of aesthetics on reformed piety rested less on images, considered to be a source of distraction, than on music. By reconsidering the evolution of Calvin's thoughts on the relationship between music and religious services between 1536 and 1543, this study reveals how Calvin came to consider that by singing the psalms, Christians could conciliate in prayer a cognitive process which was to be guided by both the meaning of the words and the emotions triggered by the tune. For Calvin, the spiritual elevation to which religious services should lead was to emerge from the conjunction of these two impetuses.