Bioengineered tooth emulation systems for regenerative and pharmacological purposes

Genetic conditions, traumatic injuries, carious lesions and periodontal diseases are all responsible for dental pathologies. The current clinical approaches are based on the substitution of damaged dental tissues with inert materials, which, however, do not ensure full physiological recovery of the teeth. Different populations of dental mesenchymal stem cells have been isolated from dental tissues and several attempts have already been made at using these stem cells for the regeneration of human dental tissues. Despite encouraging progresses, dental regenerative therapies are very far from any clinical applications. This is tightly connected with the absence of proper platforms that would model and faithfully mimic human dental tissues in their complexity. Therefore, in the last decades, many efforts have been dedicated for the development of innovative systems capable of emulating human tooth physiology in vitro. This review focuses on the use of in vitro culture systems, such as bioreactors and "organ-on-a-chip" microfluidic devices, for the modelling of human dental tissues and their potential use for dental regeneration and drug testing

Challenges and future prospects on 3D in-vitro modeling of the neuromuscular circuit

Movement of skeletal-muscle fibers is generated by the coordinated action of several cells taking part within the locomotion circuit (motoneurons, sensory-neurons, Schwann cells, astrocytes, microglia, and muscle-cells). Failure s in any part of this circuit could impede or hinder coordinated muscle movement and cause a neu romuscular disease (NMD) or determine its severity. Studying fragments of the circuit cannot provide a comprehensive and complete view of the pathological process. We trace the historic developments of studies focused on in-vitro modeling of the spinal-locomotion circuit and how bioengineered innovative technologies show advantages for an accurate mimicking of hysiological conditions of spinal-locomotion circuit. New developments on compartmentalized microfluidic culture systems (cμFCS), the use of human induced pluripotent stem cells (hiPSCs) and 3D cell-cultures are analyzed. We finally address limitations of current study models and three main challenges on neuromuscular studies: (i) mimic the whole spinal-locomotion circuit including all cell-types involved and the evaluation of independent and interdependent roles of each one; (ii) mimic the neurodegenerative response of mature neurons in-vitro as it occurs in-vivo ; and (iii) develop, tune, implement, and combine cμFCS, hiPSC, and 3D-culture technologies to ultimately create patient-specific complete, translational, and reliable NMD in-vitro model. Overcoming these challenges would significantly facilitate understanding the events taking place in NMDs and accelerate the process of finding new therapies

Challenges and Future Prospects on 3D in-vitro Modeling of the Neuromuscular Circuit

Movement of skeletal-muscle fibers is generated by the coordinated action of several cells taking part within the locomotion circuit (motoneurons, sensory-neurons, Schwann cells, astrocytes, microglia, and muscle-cells). Failures in any part of this circuit could impede or hinder coordinated muscle movement and cause a neuromuscular disease (NMD) or determine its severity. Studying fragments of the circuit cannot provide a comprehensive and complete view of the pathological process. We trace the historic developments of studies focused on in-vitro modeling of the spinal-locomotion circuit and how bioengineered innovative technologies show advantages for an accurate mimicking of physiological conditions of spinal-locomotion circuit. New developments on compartmentalized microfluidic culture systems (cμFCS), the use of human induced pluripotent stem cells (hiPSCs) and 3D cell-cultures are analyzed. We finally address limitations of current study models and three main challenges on neuromuscular studies: (i) mimic the whole spinal-locomotion circuit including all cell-types involved and the evaluation of independent and interdependent roles of each one; (ii) mimic the neurodegenerative response of mature neurons in-vitro as it occurs in-vivo; and (iii) develop, tune, implement, and combine cμFCS, hiPSC, and 3D-culture technologies to ultimately create patient-specific complete, translational, and reliable NMD in-vitro model. Overcoming these challenges would significantly facilitate understanding the events taking place in NMDs and accelerate the process of finding new therapies

Report and Abstracts of the 20th Meeting of IIM, the Interuniversity Institute of Myology: Assisi, October 12-15, 2023

The 2023 represented a milestone for the Interuniversity Institute of Myology (IIM) since it marked twenty years of IIM activity joined with the 20th annual meeting organized by the association. The 20th IIM meeting took place in the fascinating town of Assisi, in the heart of central Italy, from 12 to 15 October. The commemorative 20th edition of the meeting represented a success in terms of participation and contributions as it brought together 160 myologists, clinicians, pharmaceutical companies, and patient organization representatives from Italy, several European countries (especially France), the United Kingdom, Brazil, and the USA. Four main scientific sessions hosted 36 oral communications and 54 always-on-display posters reporting original and unpublished results. Four main lectures from internationally renowned invited speakers and talks from delegates of the Societé Française de Myologie gave particular interest and emphasis to the scientific discussion. In line with the traditional policy of the IIM to encourage the participation of young researchers, about 50% of the attendees were under 35 years old. Moreover, the 20th IIM meeting was part of the high-training course in “Advanced Myology Update 2023”, reserved to young trainees and managed by the University of Perugia (Italy) in collaboration with the IIM. In addition to the meeting scientific sessions, the 29 attendees to the course had a dedicated round table and dedicated lessons with the IIM invited speakers as teachers. Awards for the best talk, best poster blitz, and best poster have been conferred to young attendees, who became part of the IIM Young Committee, involved in the scientific organization of the IIM meetings. To celebrate the 20th IIM anniversary, a special free-access educational convention on “Causes and mechanisms of muscle atrophy. From terrestrial disuse to Space flights” has been organized, in which IIM experts in the field have illustrated the current knowledge about the muscle atrophy process in several atrophying conditions, and the former Italian astronaut, Paolo Nespoli shared his incredible experience in Space fascinating the large audience attending both in presence and online live stream. The meeting was characterized by a vibrant, friendly, and inclusive atmosphere, and stimulated discussion on emerging areas of muscle research, fostering international collaborations, and confirming the IIM meeting as an ideal venue to discuss around muscle development, function, and diseases pointing to the development of efficacious therapeutic strategies. Here, the abstracts of the meeting illustrate the most recent results on basic, translational, and clinical research in the myology field. Some abstracts are missing as per authors’ decision due to the patentability of the results

Neuron-Glial (NG) Interactions: A Microfluidic Examination of NG Emergent Responses for Repair

Neuron-glia communication is crucial to the development, plasticity, and repair of the nervous system (NS). While neurons are well known to conduct electrical impulses that transfer biological information and stimuli throughout the NS, our understanding of the roles of glia continues to evolve from when the cells were largely believed to act solely for neuronal support. Recent decades of research has shown that glia can alter metabolism, conduct impulses and change phenotype for NS repair. NG interactions have, thereby, become heavily researched in varied areas of biomedical engineering, including embryogenesis, neural regeneration, growth, and intracellular synaptic activity. However, while NG interactions are known to regulate survival, differentiation, communication, and targeted migration of neural cells, the molecular signals that orchestrate these behaviors remain incompletely understood. As a result, many emerging studies have embraced microfluidics to regulate the spatial and temporal stimuli delivered to neural cell groups and measure subsequent NG responses. The overall objective of this thesis was to examine emergent NG behavior in response to chemical stimuli within controlled microfluidic environments. Experiments examined NG behavior in the central and peripheral NS critical to neural repair. In the first model, we examined the behavior of transformed glial progenitors (in the form of Medulloblastoma (MB)), known to emulate developmental processes, to external stimuli using controlled microenvironments. We used a microfluidic system called the bridged mlane, which allows for steady-state, 1D, controllable concentration gradients along the length of its’ microchannel. The system was used to evaluate in vitro migratory responses of MB-derived cells to external signaling from Epidermal Growth Factor (EGF) and stromal cell-derived factor 1-alpha (SDF-1). Data demonstrated that MB cells exhibit dosage-dependent chemotaxis towards increasing concentration gradients. However, as glial behaviors are intricately linked with that of neuronal cells, we next used a more comprehensive neural model to examine the collective behavior of neural progenitors in response to chemotactic stimulation. Experiments examined the collective behavior of NG progenitor cell populations in response to stimulation via fibroblast growth factor (FGF) gradients using a developmental model of the central nervous system (CNS) in the Drosophila Melanogaster, 3rd instar larvae stage. Surprisingly, our data demonstrated that cells migrated larger distances and with higher directionality within collective groups of both neuronal and glial progenitors than in populations of glia only. Taken together, these results helped elucidate different modalities for directed movement that can be used for therapeutic techniques that leverage the interdependent NG relationship. The last model examined NG contributions to the formation of neuromuscular junctions (NMJ) in the peripheral nervous system (PNS). The glial component of the NMJ, the Schwann cells (SCs), are essential to NMJ development and function including remodeling and regeneration. SCs are critical for PNS regeneration, where studies have shown SC are able to trans-differentiate in order to create glial bridges that bypass non-functional neuronal nodes and isolate damaged neurons. However recent NMJ models mainly focus on motor neurons (MN) and muscle cells (MCs), some in vitro work has been utilized to study SCs, but their overall roles still remain to be well-defined and studied. To that end, the experiments used a compartmentalized microfluidic platform to demonstrate reproducible differentiation of skeletal myotubes with increased viability and length following the time-dependent addition of neuronal and glial cells. We lastly probed the guidance cues and migratory patterns of NGs towards various growth factors to elucidate emergent NMJ response. Our data illustrated there is a co-culture effect on receptor expression dependent on stimulation time. The data point to SCs as key players in stabilizing and maintaining in vitro NMJ models that will aid the development and testing of emerging therapies for neuromuscular dysfunction