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Magnetically Assisted Tissue Engineering Technologies for Tendon Regeneration

Periodic Reporting for period 2 - MagTendon (Magnetically Assisted Tissue Engineering Technologies for Tendon Regeneration)

Reporting period: 2019-11-01 to 2021-04-30

Musculoskeletal diseases are one of the leading causes of disability worldwide, affecting 1 in 2 adults, which correspond to twice the rate of chronic heart and lung conditions. Tendon injuries account for a considerable share of musculoskeletal pathologies. Their load-bearing and load-transfer functions predisposes tendons to injuries that can dramatically affect patient’s quality of life, being estimated that over 30 million human tendon-related procedures are taking place annually worldwide. Most often, tendon injuries are managed with conservative approaches and/or surgical interventions, using autografts or allografts. Tendon healing process is a complex cascade of biological events that are not yet fully understood, orchestrated by numerous cytokines and initiated by an inflammatory step. This process is never fully accomplished, which explains the fact that tendon never regains its initial biomechanical functionality.
The poor healing ability of tendons as well as the limitations of currently used therapies have motivated tissue engineering (TE) strategies to develop living tendon substitutes. MagTendon will explore conventional and innovative tools such as multimaterial 3 dimensional (3D) bioprinting to design magnetic responsive systems mimicking specific aspects of tendon tissue architecture, composition and biomechanical properties, which, combined with adequate stem cells, will render appropriate behavioural instructions to stimulate the regeneration of tendon tissue. MagTendon proposes expanding the boundaries of research in this field, fulfilling the currently unmet requirements for tendon TE by proposing disruptive technological concepts for 1) producing advanced nanoplatforms for stem cell selection/activation; 2) conceiving innovative magnetic stimuli-responsive 3D constructs with biomimetic architecture and mechanical behaviour, where laden stem cells will be governed by their ability to sense their environment and respond to structural and biomechanical cues being guided into the tenogenic lineage; 3) evolving the 3D laden magnetic system into sophisticated tissue models for enabling greater understanding on the molecular mechanisms involved in tendon development and healing that will be returned for designing improved technologies and therapies; 4) widening the therapeutical window of the developed TE approaches by remote activation of the implanted magnetic systems using extracorporeal magnetic devices. With this, novel therapies that more closely recapitulate tendon morphogenesis will be obtained, with the ultimate goal of achieving regeneration over simple repair of tendon tissue, but that can be extended to approaches targeting other tissues and organs of the human body.
During this first reporting period of MagTendon, efforts were made to establish new protocols with local Hospitals and update the ones already implemented in order to increase the number/availability of biological samples (human tendon tissues and human adipose tissues). These samples will be used to isolate tendon-derived cells and adipose tissue derived stem cells to be used in the several studies foreseen in the project, in quantity and in quality, in the sense that MagTendon proposes to study dissimilar aspects of healthy and diseased/injured tendons. Having also in mind the tasks and experimental setups in the upcoming years of MagTendon, the PI and team have submitted the necessary documents to the national regulatory entities for laboratory animal experimentation (DGAV, Portugal) so that in vivo experiments (task 4) could be initiated in early 2020. Tasks 1, 2 and 3 are being executed as planned, and work was also initiated under the scope of task 4. In task 1, antigenically‐defined subsets of human adipose stem cells (hASCs) are being investigated for tenogenic commitment capacity, and different inflammation-associated receptors and cell mechanosensitive receptors are also under study. These mechanotransduction mechanisms are being investigated in 2D and 3D magnetic responsive systems approaches. Under task 2, several different works are ongoing concerning the development of fiber-based magnetic responsive systems using biotextile technologies as well as the devolpment of different bioinks for 3D printing of tissue analogues and tissue models (tendon-on—a-chip).
The results achieved so far have resulted in a significant number of publications in high impact journals and 1 patent request is being prepared to submit soon. An ERC proof of Concept (PoC) project proposal was also submitted in the September 2020 call.
MagTendon is using state-of-the-art fiber based technologies, but is also exploring the most recent processing technologies such as 3D bioprinting to achieve biomimetic architectures and mechanically competent structures. 3D bioprinting is a process in which cells and biomaterials (bioink) are deposited simultaneously in defined 3D patterns and shapes through bottom-up assembly, enabling the biofabrication of cell/material constructs with increased complexity and design resolution, with selected geometries printed at defined positions of the 3D space. In combination with computer-aided design/computer-aided manufacturing (CAD/CAM) systems, 3D bioprinting enables the conversion of medical images into tissue constructs for patient-personalized organ repair. However, despite the recognized potential and remarkable examples of successful TE strategies based on 3D bioprinting that have been increasingly reported in recent years, specific applications targeting tendon regeneration are almost inexistent. From the polymeric materials point of view, it remains a challenge to develop unique bioinks, taking in account the required biological competence and the physical requirements dictated by the biofabrication process, Advances in this area will surely contribute to solve one of the major bottlenecks of the field, but merging 3D bioprinting with nanotechnologies will extend the potential of biofabrication approaches far beyond of the current concepts. The incorporation of SPMNs into the bioink systems (nanoinks) will enable the mechanical/magnetic stimulation of embedded cells by remote actuation with external magnetic fields. Besides its main envisioned functionality as remote actuators, the development of magnetic nanoinks will open a much wider construct design space beyond 3D shaping and cell patterning. Building on the recently introduced multimaterial magnetically assisted 3D printing concept, it is foreseen the possibility of incorporating defined nano and microstructural features into the construct which can result in a closer mimicry of tendon tissues. Multimaterial 3D bioprinting also enables the simultaneous production of the engineered cell-laden construct on their own perfusable bioreactor (organ-on-a-chip), proving a convenient platform for studying combinations of multiple experimental parameters at sizable scales. Ultimately, it may result on the production of miniaturized tissue models reproducing physiological processes, but also pathological conditions, namely specific biochemical, biophysical and mechanical features that characterize a specific condition/disease, providing high-content screening models to advance knowledge on physiological and pathological mechanisms that will input the development of new and improved therapies while minimizing animal experimentation.
MagTendon proposes expanding the boundaries of research in this field, fulfilling the currently unmet requirements for tendon tissue engineering by proposing disruptive technological concepts for 1) producing advanced nanoplatforms for stem cell selection/activation; 2) conceiving innovative magnetic stimuli-responsive 3D constructs with biomimetic architecture and mechanical behaviour, where laden stem cells will be governed by their ability to sense their environment and respond to structural and biomechanical cues being guided into the tenogenic lineage 3) evolving the 3D laden magnetic system into sophisticated tissue models for enabling greater understanding on the molecular mechanisms involved in tendon development and healing that will be returned for designing improved technologies and therapies; 4) widening the therapeutical window of the developed TE approaches by remote activation of the implanted magnetic systems using external magnetic devices. With this, novel therapies that more closely recapitulate tendon morphogenesis will be obtained, with the ultimate goal of achieving regeneration over simple repair of tendon tissue, but that can be extended to approaches targeting other tissues and organs of the human body.