Magnetic resonance imaging and ultrasound elastography in the context of preclinical pharmacological research: significance for the 3R principles

The 3Rs principles—reduction, refinement, replacement—are at the core of preclinical research within drug discovery, which still relies to a great extent on the availability of models of disease in animals. Minimizing their distress, reducing their number as well as searching for means to replace them in experimental studies are constant objectives in this area. Due to its non-invasive character in vivo imaging supports these efforts by enabling repeated longitudinal assessments in each animal which serves as its own control, thereby enabling to reduce considerably the animal utilization in the experiments. The repetitive monitoring of pathology progression and the effects of therapy becomes feasible by assessment of quantitative biomarkers. Moreover, imaging has translational prospects by facilitating the comparison of studies performed in small rodents and humans. Also, learnings from the clinic may be potentially back-translated to preclinical settings and therefore contribute to refining animal investigations. By concentrating on activities around the application of magnetic resonance imaging (MRI) and ultrasound elastography to small rodent models of disease, we aim to illustrate how in vivo imaging contributes primarily to reduction and refinement in the context of pharmacological research

In vivo preclinical low field MRI monitoring of tumor growth following a suicide gene therapy in an orthotopic mice model of human glioblastoma

International audienc

Matrigel 3D bioprinting of contractile human skeletal muscle models recapitulating exercise and pharmacological responses

A key to enhance the low translatability of preclinical drug discovery are in vitro human three-dimensional (3D) microphysiological systems (MPS). Here, we show a new method for automated engineering of 3D human skeletal muscle models in microplates and functional compound screening to address the lack of muscle wasting disease medication. To this end, we adapted our recently described 24-well plate 3D bioprinting platform with a printhead cooling system to allow microvalve-based drop-on-demand printing of cell-laden Matrigel containing primary human muscle precursor cells. Mini skeletal muscle models develop within a week exhibiting contractile, striated myofibers aligned between two attachment posts. As an in vitro exercise model, repeated high impact stimulation of contractions for 3 h by a custom-made electrical pulse stimulation (EPS) system for 24-well plates induced interleukin-6 myokine expression and Akt hypertrophy pathway activation. Furthermore, the known muscle stimulators caffeine and Tirasemtiv acutely increase EPS-induced contractile force of the models. This validated new human muscle MPS will benefit development of drugs against muscle wasting diseases. Moreover, our Matrigel 3D bioprinting platform will allow engineering of non-self-organizing complex human 3D MPS

Mettre en œuvre un service de questions-réponses en ligne

En quelques années, les bibliothèques françaises ont développé des services de questions-réponses en ligne. Beaucoup d'établissements en sont encore à la phase de réflexion, d'autres démarrent, des réseaux s'élaborent. Dans le contexte actuel du repérage, de la sélection et de la validation de l'information pléthorique disponible sur Internet, les services de questions-réponses en ligne ont un rôle primordial à jouer. En effet, ils valorisent l'offre des bibliothèques dans le contexte du développement des services aux publics et des services à distance. Leur mise en place interroge le professionnel sous de multiples facettes : organisation du travail, politique de services, choix des outils… Ces différents aspects sont abordés, s'appuyant sur des expériences françaises et étrangères, qu'elles soient locales, coopératives et/ou collaboratives. Un éventail d'offres existe aujourd'hui, selon les objectifs, les besoins, les publics, les moyens mis à disposition et les technologies choisies. Le plan s'articule autour de quatre parties pragmatiques et opératoires : construire le projet, développer un savoir-répondre, organiser et travailler au sein d'une équipe et, enfin, adapter le service à l'environnement et à la nature de ses publics. Cet ouvrage collectif, coordonné par Claire Nguyen, se veut un guide utile à tous les professionnels qui veulent créer, maintenir ou faire évoluer un service de questions-réponses à distance

Un premier pas vers l’étude du collagène du cartilage articulaire en microscopie électronique

Le cartilage articulaire est localisé à la surface des os impliqués dans une articulation et permet des mouvements avec un minimum de friction tout en agissant comme surface supportant les charges. Etant donné le nombre croissant de patients souffrant de pathologies telles que l’ostéoarthrite et l’arthrite rhumatoïde, l’étude du cartilage articulaire prend de plus en plus d’importance. Le cartilage articulaire est un sujet de choix pour être étudié par une technique d’imagerie de haute résolution comme la technique de microscopie électronique à transmission (MET), mais cette approche est complexe dû à la prépondérance de la matrice extracellulaire, composée essentiellement de protéoglycanes et de collagène et très difficile de préserver et colorer pour en extraire des informations sur l’ultrastructure. Afin de vérifier notre méthodologie pour reproduire des données déjà disponibles sur l’imagerie du cartilage par MET, et ainsi corréler les images avec le contenu en collagène, nous avons appliqué la MET à l’étude du ménisque et du plateau cartilagineux fémoral d’une articulation de la patte postérieure d’un rat adulte. Grâce à la préparation classique du tissu pour la MET focalisant sur la préservation du collagène au détriment des protéoglycanes, nous avons pu reproduire les données publiées et différencier les deux tissus en fonction de leur type de collagène prépondérant. La prochaine étape de notre travail sera d’utiliser ces images de MET pour valider les images de microscopie électronique à balayage (MEB) que nous aimerions générer à partir des mêmes tissus

NON-INVASIVE IMAGING DEMONSTRATES CLINICAL FEATURES OF THE PATHOLOGY IN A RAT ADJUVANT MODEL FOR ANKYLOSING SPONDYLITIS

Ankylosing spondylitis (AS) is a common rheumatic diseases involving both inflammatory erosive osteopenia and bony overgrowth. When lesions occur in the spine, vertebrae may fuse. The most effective AS medication comprises biologic agents blocking TNF-α, which are best given early in disease when the inflammatory burden is greatest. Since response rates to TNF blockers are only 60%, there is a need for more effective therapies for this debilitating disease. An important phase of drug discovery comprises compound assessment in relevant animal models. Changes at the spine of small rodents due to challenge with complete Freund’s adjuvant (CFA) recapitulate some features of AS. In view of preclinical compound testing and translational applications, magnetic resonance imaging (MRI) was applied to follow longitudinally in vivo, at the level of the rat spine, changes induced by CFA inoculation into the tail. Signals reflecting inflammation have been detected throughout the experimental period and peaked at day 27 after CFA. At day 14 the inflammatory response occurred along ligaments but it expanded to nearby soft tissues at later time points. From day 27 onwards inflammation was also detected within the bone, in areas where erosion occurred, and bone-like structures were formed. Post-mortem analyses at the end of the study including high resolution micro-CT and histology of the isolated spine confirmed the inflammation and bone remodeling observed in vivo

Chemokine-like receptor 1 plays a critical role in modulating the regenerative and contractile properties of muscle tissue.

Musculoskeletal diseases are a leading contributor to mobility disability worldwide. Since the majority of patients with musculoskeletal diseases present with associated muscle weakness, treatment approaches typically comprise an element of resistance training to restore physical strength. The health-promoting effects of resistance exercise are mediated via complex, multifarious mechanisms including modulation of systemic and local inflammation. Here we investigated whether targeted inhibition of the chemerin pathway, which largely controls inflammatory processes via chemokine-like receptor 1 (CMKLR1), can improve skeletal muscle function. Using genetically modified mice, we demonstrate that blockade of CMKLR1 transiently increases maximal strength during growth, but lastingly decreases strength endurance. In-depth analyses of the underlying long-term adaptations revealed microscopic alterations in the number of Pax7-positive satellite cells, as well as molecular changes in genes governing myogenesis and calcium handling. Taken together, these data provide evidence of a critical role for CMKLR1 in regulating skeletal muscle function by modulating the regenerative and contractile properties of muscle tissue. CMKLR1 antagonists are increasingly viewed as therapeutic modalities for a variety of diseases (e.g., psoriasis, metabolic disorders, and multiple sclerosis). Our findings thus have implications for the development of novel drug substances that aim at targeting the chemerin pathway for musculoskeletal or other diseases