Traumatic injuries to the peripheral nervous system (PNI) can lead to severe consequences such as paralysis. Unfortunately, current treatments rarely allow for satisfactory functional recovery. The ...high healthcare costs associated with PNS injuries, worker disability, and low patient satisfaction press for alternative solutions that surpass current standards. For the treatment of injuries with a deficit of less than 30 mm to bridge, the use of synthetic nerve conduits (NGC) is favored. However, to develop such promising therapeutic strategies, in vitro models that more faithfully mimic nerve physiology are needed. The absence of a clinically scaled model with essential elements such as a three-dimension environment and dynamic coculture has hindered progress in this field. The presented research focuses on the development of an in vitro coculture model of the peripheral nervous system (PNS) involving the use of functional biomaterial which microstructure replicates nerve topography. Initially, the behavior of neuron-derived cell lines (N) and Schwann cells (SC) in contact with a short section of biomaterial (5 mm) was studied. Subsequent investigations, using fluorescent markers and survival assays, demonstrated the synergistic effects of coculture. These optimized parameters were then applied to longer biomaterials (30 mm), equivalent to clinically used NGC. The results obtained demonstrated the possibility of maintaining an extended coculture of SC and N over a 7-day period on a clinically scaled biomaterial, observing some functionality. In the long term, the knowledge gained from this work will contribute to a better understanding of the PNS regeneration process and promote the development of future therapeutic approaches while reducing reliance on animal experimentation. This model can be used for drug screening and adapted for personalized medicine trials. Ultimately, this work fills a critical gap in current research, providing a transformative approach to study and advance treatments for PNS injuries.
Peripheral nerve injuries (PNIs) are detrimental to the quality of life of affected individuals. Patients are often left with life-long ailments that affect them physically and psychologically. ...Autologous nerve transplant is still the gold standard treatment for PNIs despite limited donor site and partial recovery of nerve functions. Nerve guidance conduits are used as a nerve graft substitute and are efficient for the repair of small nerve gaps but require further improvement for repairs exceeding 30 mm. Freeze-casting is an interesting fabrication method for the conception of scaffolds meant for nerve tissue engineering since the microstructure obtained comprises highly aligned micro-channels. The present work focuses on the fabrication and characterization of large scaffolds (35 mm length, 5 mm diameter) made of collagen/chitosan blends by freeze-casting via thermoelectric effect instead of traditional freezing solvents. As a freeze-casting microstructure reference, scaffolds made from pure collagen were used for comparison. Scaffolds were covalently crosslinked for better performance under load and laminins were further added to enhance cell interactions. Microstructural features of lamellar pores display an average aspect ratio of 0.67 ± 0.2 for all compositions. Longitudinally aligned micro-channels are reported as well as enhanced mechanical properties in traction under physiological-like conditions (37 °C, pH = 7.4) resulting from crosslinking treatment. Cell viability assays using a rat Schwann cell line derived from sciatic nerve (S16) indicate that scaffold cytocompatibility is similar between scaffolds made from collagen only and scaffolds made from collagen/chitosan blend with high collagen content. These results confirm that freeze-casting via thermoelectric effect is a reliable manufacturing strategy for the fabrication of biopolymer scaffolds for future peripheral nerve repair applications.
En matière criminelle et pénale au Québec, les activités des tribunaux sont le plus souvent mesurées en termes de nombre de causes ou de décisions rendues. Mais c’est un tout autre défi de tenter de ...les mesurer en termes d’efficacité. Coûts de la justice, taux de confiance des usagers ou taux de récidive restent, encore et toujours, les indices les plus recherchés, mais aussi les plus inaccessibles ou contestés, pour évaluer le bon fonctionnement de notre système de justice. Cette étude présente les taux de récidive (qualifiés plutôt de « réentrée » dans le système de justice) d’accusés admis au programme de mesures de rechange général pour adultes à la Cour du Québec. Se trouvant être à la fois un programme de justice réparatrice et un programme alternatif aux procédures judiciaires, ce programme a été mis en oeuvre pour la première fois à l’automne 2017. La trajectoire des 1 000 premiers dossiers admis au programme a pu être observée de 2017 à 2022. Les dossiers ont été suivis en temps réel pendant une période de deux ans après la fin de la date de réalisation de la mesure de justice réparatrice par l’accusé. Les résultats montrent que plus d’un tiers des accusés avaient des antécédents judiciaires avant d’être admis au programme, et que seulement 93 sur 1 000 semblent de nouveau avoir été inscrits pour une nouvelle infraction dans le registre des dossiers judiciaires du Québec, dans les deux ans après la fin de leur mesure. Les résultats, tout en tentant d’apporter une contribution à la mesure de l’efficacité des programmes judiciaires au Québec, mettent en évidence les enjeux liés à l’utilisation de telles mesures, dès lors qu’il s’agit d’observer des programmes fondés sur des initiatives hybrides, à la fois pénales et sociales.
