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Human adipose-derived mesenchymal stromal cells (A-MSC) are promising tools for regenerative medicine, but their in vitro amplification before administration is still an issue. Microcarriers emerge as a novel approach for A-MSC expansion in bioreactors. Here, microcarriers with different shapes and functionalizations were compared according to their efficiency for A-MSC expansion. In particular, novel disc shape microcarriers were compared to the commonly used spherical microcarriers. This geometry increases their specific surface while presenting a flat surface, close to monolayer culture conditions. Several parameters were evaluated, such as cell amplification and harvesting yields, cell viability, and cell identity after culture. We observed that microcarriers shape and functionalization impact several A-MSC amplification process steps. However, GhaterDisc-3 microcarriers were the best alternative since harvesting is highly facilitated compared to other microcarriers with a yield of virtually 100 %. Furthermore, A-MSC identity was maintained, since A-MSC keep their characteristic immunophenotype and tri-lineage differentiation ability. Moreover, as these microcarriers are free from any animal derived components, they might be suitable for a use in a GMP compliant large-scale A-MSC production for biomedical applications.

While motor recovery following mild stroke has been extensively studied with neuroimaging, mechanisms of recovery after moderate to severe strokes of the types that are often the focus for novel restorative therapies remain obscure. We used fMRI to: 1) characterize reorganization occurring after moderate to severe subacute stroke, 2) identify brain regions associated with motor recovery and 3) to test whether brain activity associated with passive movement measured in the subacute period could predict motor outcome six months later. Because many patients with large strokes involving sensorimotor regions cannot engage in voluntary movement, we used passive flexion-extension of the paretic wrist to compare 21 patients with subacute ischemic stroke to 24 healthy controls one month after stroke. Clinical motor outcome was assessed with Fugl-Meyer motor scores (motor-FMS) six months later. Multiple regression, with predictors including baseline (one-month) motor-FMS and sensorimotor network regional activity (ROI) measures, was used to determine optimal variable selection for motor outcome prediction. Sensorimotor network ROIs were derived from a meta-analysis of arm voluntary movement tasks. Bootstrapping with 1000 replications was used for internal model validation. During passive movement, both control and patient groups exhibited activity increases in multiple bilateral sensorimotor network regions, including the primary motor (MI), premotor and supplementary motor areas (SMA), cerebellar cortex, putamen, thalamus, insula, Brodmann area (BA) 44 and parietal operculum (OP1-OP4). Compared to controls, patients showed: 1) lower task-related activity in ipsilesional MI, SMA and contralesional cerebellum (lobules V-VI) and 2) higher activity in contralesional MI, superior temporal gyrus and OP1-OP4. Using multiple regression, we found that the combination of baseline motor-FMS, activity in ipsilesional MI (BA4a), putamen and ipsilesional OP1 predicted motor outcome measured 6 months later (adjusted-R2 = 0.85; bootstrap p, Highlights • Motor recovery after stroke can be robustly predicted using a passive task fMRI paradigm. • Sensorimotor network activity is decreased in moderate to severe stroke patients relative to healthy controls • Compensatory mechanisms in severe stroke involve both the dorsal (MI BA4a), and the ventral (OP1 and OP4) sensorimotor stream

Introduction Le developpement de vaccins anti-tumoraux est une approche prometteuse dans le traitement du melanome notamment en combinaison avec les inhibiteurs de points de controle immunitaire (ICI) car l’efficacite des ICI requiert une immunite anti-tumorale prealable. Les cellules dendritiques plasmocytoides representent un candidat ideal pour cette approche car elles sont capables d’induire de fortes reponses anti-tumorales. Nous avons developpe un vaccin anti-tumoral fonde sur une lignee de cellules dendritiques plasmocytoides allogeniques ayant une forte capacite de presentation antigenique et ciblant 4 antigenes de melanome, appelee GeniusVac-Mel4. Materiel et methodes Essai de phase 1b multicentrique, non randomise, en ouvert etudiant l’effet du vaccin GeniusVac-Mel4 en injections sous-cutanees en escalade de dose : 4, 20, 60 millions de cellules irradiees chargees avec 4 peptides de melanome (MLANA, MAGEA3, PMEL, TYR) a raison de 3 injections a 1 semaine d’intervalle, chez des patients HLA A*02 :01 atteints de melanome metastatique, en 2e ligne ou plus de traitement systemique. L’objectif primaire etait l’evaluation de la securite et de la tolerance, les objectifs secondaires etaient l’evaluation des reponses clinique et biologique. Resultats Entre juin 2013 et mars 2016, 9 patients atteints de melanome metastatique (5 femmes et 4 hommes, âge moyen 71,8 ans) ont ete inclus. Le vaccin etait bien tolere. Ainsi, 22 evenements indesirables severes ont ete rapportes chez 8 patients, mais aucun n’etait relie au traitement a l’etude. Concernant la reponse clinique, une stabilisation de la maladie selon les criteres IRCs etait constatee chez 4 patients avec de plus une depigmentation vitiligoide chez l’un des patients. Quatre patients etaient encore en vie a la semaine 48 parmi lesquels 2 n’avaient pas recu de nouvelle ligne de traitement. L’immuno-monitoring a montre l’absence de reponse allogenique developpee in vivo vis-a-vis du vaccin. Une augmentation significative des lymphocytes T CD8+ circulants specifiques d’antigenes tumoraux a ete mise en evidence chez 2 patients, accompagnee d’une bascule d’un phenotype de lymphocytes T naifs (CD45RA + CCR7+) vers un phenotype de lymphocytes T memoires (CD45RA-CCR7-). De plus, des experiences menees ex vivo ont montre que l’association d’un anti-PD1 en combinaison avec Genius Vac avait un effet synergique sur l’expansion de la reponse CD8+ specifique. Discussion Cette etude de phase 1b a demontre la capacite de Genius VAc mel-4 a generer une reponse lymphocytaire T CD8 + specifique chez des patients atteints de melanome avec un profil de tolerance satisfaisant (Charles et al., Oncoimmunology 2020). Nous envisageons de poursuivre cette approche en combinaison avec un anti-PD1 dans un essai clinique de phase 2.

L’ischemia cerebrale (IC) rappresenta l’80% degli accidenti vascolari cerebrali (AVC), seconda causa di mortalita nel mondo. Essa fa seguito all’interruzione del flusso ematico in un’arteria cerebrale. Si definisce come una riduzione della pressione di perfusione cerebrale sotto la soglia di autoregolazione fisiologica del flusso ematico cerebrale, che conduce a un insufficiente apporto in ossigeno e in energia. Si tratta di un fenomeno che evolve molto rapidamente nel tempo e nello spazio, andando dal «silenzio elettrofisiologico» di neuroni ancora vitali (penombra) alla necrosi irreversibile (infarto). La risonanza magnetica o la TC di perfusione permettono di visualizzare in urgenza queste zone di IC. I meccanismi che inducono la morte cellulare (omeostasi di Ca2+, Na+/Cl–, K+ ed eccitotossicita, depolarizzazione peri-infartuale, stress ossidativo, infiammazione, ecc.) non sono limitati ai neuroni. Essi coinvolgono l’insieme dell’unita neurovascolare, gli oligodendrociti e la microglia. Inoltre, l’immunodepressione sistemica causata dall’AVC e responsabile di infezioni che peggiorano la prognosi funzionale. E necessaria una migliore comprensione integrativa «al di la del neurone» di questi fenomeni per sviluppare dei trattamenti limitati, a tutt’oggi, alla gestione specializzata delle AVC, alla riperfusione per trombolisi e all’emicraniectomia decompressiva per gli infarti estesi. Parallelamente ai meccanismi deleteri, esistono una neuroprotezione endogena iniziale e, poi, un recupero che dura diversi mesi. Questo recupero, facilitato dalla rieducazione, e legato a un compenso dei deficit e alla plasticita cerebrale: riorganizzazione dei circuiti danneggiati e neurosinaptogenesi in relazione con la glia e i microvasi all’interno di «nicchie neuro-oligo-vascolari» perilesionali. L’ottimizzazione di questa plasticita multicellulare e, oggi, l’obiettivo di trattamenti promettenti di medicina rigenerativa basati sull’utilizzo di fattori di crescita e di cellule staminali o differenziate (terapia cellulare).