Objective: The surgical management of nasal septal defects due to perforations, malformations, congenital cartilage absence, traumatic defects, or tumors would benefit from availability of optimally matured septal cartilage substitutes. Here, we aimed to improve in vitro maturation of 3-dimensional (3D)-printed, cell-laden polycaprolactone (PCL)-based scaffolds and test their in vivo performance in a rabbit auricular cartilage model. Design: Rabbit auricular chondrocytes were isolated, cultured, and seeded on 3D-printed PCL scaffolds. The scaffolds were cultured for 21 days in vitro under standard culture media and normoxia or in prochondrogenic and hypoxia conditions, respectively. Cell-laden scaffolds (as well as acellular controls) were implanted into perichondrium pockets of New Zealand white rabbit ears ( N = 5 per group) and followed up for 12 weeks. At study end point, the tissue-engineered scaffolds were extracted and tested by histological, immunohistochemical, mechanical, and biochemical assays. Results: Scaffolds previously matured in vitro under prochondrogenic hypoxic conditions showed superior mechanical properties as well as improved patterns of cartilage matrix deposition, chondrogenic gene expression ( COL1A1, COL2A1, ACAN, SOX9, COL10A1), and proteoglycan production in vivo, compared with scaffolds cultured in standard conditions. Conclusions: In vitro maturation of engineered cartilage scaffolds under prochondrogenic conditions that better mimic the in vivo environment may be beneficial to improve functional properties of the engineered grafts. The proposed maturation strategy may also be of use for other tissue-engineered constructs and may ultimately impact survival and integration of the grafts in the damaged tissue microenvironment.

Amyotrophic Lateral Sclerosis (ALS) is a multisystemic neurodegenerative disorder, with accumulating evidence indicating metabolic disruptions in the skeletal muscle preceding disease symptoms, rather than them manifesting as a secondary consequence of motor neuron (MN) degeneration. Hence, energy homeostasis is deeply implicated in the complex physiopathology of ALS and skeletal muscle has emerged as a key therapeutic target. Here, we describe intrinsic abnormalities in ALS skeletal muscle, both in patient-derived muscle cells and in muscle cell lines with genetic knockdown of genes related to familial ALS, such as TARDBP (TDP-43) and FUS. We found a functional impairment of myogenesis that parallels defects of glucose oxidation in ALS muscle cells. We identified FOXO1 transcription factor as a key mediator of these metabolic and functional features in ALS muscle, via gene expression profiling and biochemical surveys in TDP-43 and FUS-silenced muscle progenitors. Strikingly, inhibition of FOXO1 mitigated the impaired myogenesis in both the genetically modified and the primary ALS myoblasts. In addition, specific in vivo conditional knockdown of TDP-43 or FUS orthologs (TBPH or caz) in Drosophila muscle precursor cells resulted in decreased innervation and profound dysfunction of motor nerve terminals and neuromuscular synapses, accompanied by motor abnormalities and reduced lifespan. Remarkably, these phenotypes were partially corrected by foxo inhibition, bolstering the potential pharmacological management of muscle intrinsic abnormalities associated with ALS. The findings demonstrate an intrinsic muscle dysfunction in ALS, which can be modulated by targeting FOXO factors, paving the way for novel therapeutic approaches that focus on the skeletal muscle as complementary target tissue.

The development of inks with suitable rheological, physicochemical, mechanical, and biological properties is crucial for the successful fabrication of functional scaffolds via extrusion-based 3D printing. In this study, collagen/chitosan hydrogels with varying polymer ratios were developed and characterized to evaluate their printability and suitability for cartilage tissue engineering. Rheological analyses revealed that all samples exhibited shear-thinning behavior and solid-like viscoelasticity, with the formulation of an 80:20 COL/CHI ratio (20CHI) demonstrating optimal filament formation and dimensional stability. Physicochemical analyses confirmed the preservation of the collagen triple helix and the formation of hydrogen bonding between chitosan and collagen. 20CHI scaffolds showed swelling capacity and high cohesiveness. In vitro studies confirmed the cytocompatibility of the scaffolds with murine fibroblasts and the ability of the scaffolds to promote adhesion, proliferation, and extracellular matrix production of both chondrocytes and adipogenic mesenchymal stem cells (aMSCs). Quantification of sulfated glycosaminoglycan (sGAG) indicated sustained matrix deposition over 28 days, particularly by chondrocytes. These findings demonstrate that 20CHI hydrogel is a promising candidate for 3D printing of biomimetic scaffolds for cartilage regeneration.

Amyotrophic Lateral Sclerosis (ALS) is a multisystemic neurodegenerative disorder, with accumulating evidence indicating metabolic disruptions in the skeletal muscle preceding disease symptoms, rather than them manifesting as a secondary consequence of motor neuron (MN) degeneration. Hence, energy homeostasis is deeply implicated in the complex physiopathology of ALS and skeletal muscle has emerged as a key therapeutic target. Here, we describe intrinsic abnormalities in ALS skeletal muscle, both in patient-derived muscle cells and in muscle cell lines with genetic knockdown of genes related to familial ALS, such as TARDBP (TDP-43) and FUS . We found a functional impairment of myogenesis that parallels defects of glucose oxidation in ALS muscle cells. We identified FOXO1 transcription factor as a key mediator of these metabolic and functional features in ALS muscle, via gene expression profiling and biochemical surveys in TDP-43 and FUS silenced muscle progenitors. Strikingly, inhibition of FOXO1 mitigated the impaired myogenesis in both the genetically modified and the primary ALS myoblasts. In addition, specific in vivo conditional knockdown of TDP-43 or FUS orthologs ( TBPH or caz ) in Drosophila muscle precursor cells resulted in decreased innervation and profound dysfunction of motor nerve terminals and neuromuscular synapses, accompanied by motor abnormalities and reduced lifespan. Remarkably, these phenotypes were partially corrected by foxo inhibition, bolstering the potential pharmacological management of muscle intrinsic abnormalities associated with ALS. The findings demonstrate an intrinsic muscle dysfunction in ALS, which can be modulated by targeting FOXO factors, paving the way for novel therapeutic approaches that focus on the skeletal muscle as complementary target tissue.

This paper presents the outcomes of the project for applications of 3D printing technology in healthcare. The anatomical 3D modelling was carried out, and the 3D digital anatomical models were developed from the CT scan medical images, through medical images acquisition, segmentation, preparation, 3D printing and post-processing processes. Furthermore, the 3D digital models were converted into 3D physical models through Fused Deposition Modeling (FDM) and Stereolithography (SLA) 3D printing technologies. The segmentation and preparation processes were performed by employing 3D Slicer V5.8.0 and Meshmixer Autodesk V3.5software, respectively. The 3D digital models were prepared for printing using GrabCAD print V1.88 and Preform V3.36.0 software for FDM and SLA 3D printing technologies, respectively. During the models’ printing preparations, the printing parameters’ settings were performed, and the G-Codes were generated, which then sent to the printers. The printed models are to be used for training and research at University of Namibia. In addition to manual segmentation, AI-based segmentation which is an automated segmentation was also performed, and the models generated from the two segmentation methods were compared.