3D-Printed Extracellular Matrix/Polyethylene Glycol Diacrylate Hydrogel Incorporating the Anti-inflammatory Phytomolecule Honokiol for Regeneration of Osteochondral Defects

Abstract

Background: Osteoarthritis is the leading cause of disability worldwide; cartilage degeneration and defects are the central features. Significant progress in tissue engineering holds promise to regenerate damaged cartilage tissue. However, a formidable challenge is to develop a 3-dimensional (3D) tissue construct that can regulate local immune environment to facilitate the intrinsic osteochondral regeneration. Purpose: This study is to evaluate efficacy of a 3D-printed decellularized cartilage extracellular matrix (ECM) and polyethylene glycol diacrylate (PEGDA) integrated novel scaffold (PEGDA/ECM) together with the natural compound honokiol (Hon) for regenerating osteochondral defect. Study Design: Controlled laboratory study. Methods: We used a stereolithography-based 3D printer for PEGDA/ECM bioprinting. A total of 36 Sprague-Dawley rats with cylindrical osteochondral defect in the trochlear groove of the femur were randomly assigned into 3 different treatments: no scaffold implantation (Defect group), 3D printed PEGDA/ECM scaffold alone (PEGDA/ECM group), or Hon suspended in a 3D-printed PEGDA/ECM scaffold (PEGDA/ECM/Hon group). 12 rats that underwent only medial parapatellar incision surgery were used as normal controls. The femur specimens were postoperatively harvested at 4 and 8 weeks for gross, micro-CT, and histological evaluations. The efficacy of PEGDA/ECM/Hon scaffold on the release of proinflammatory cytokines from the macrophages stimulated by lipopolysaccharide (LPS) was evaluated in-vitro. Results: In-vitro results determined that PEGDA/ECM/Hon scaffold could suppress the release of proinflammatory cytokines from macrophages that were stimulated by LPS. Macroscopic images showed that the PEGDA/ECM/Hon group had significantly higher ICRS scoring than that of defect and PEGDA/ECM groups. Micro-CT evaluation demonstrated that much more bony tissue was formed in the defect sites implanted with the PEGDA/ECM scaffold or PEGDA/ECM/Hon scaffold compared with the untreated defects. Histological analysis showed that the PEGDA/ECM/Hon group had a significant enhancement in osteochondral regeneration at 4 and 8 weeks after surgery in comparison with the ECM/PEGDA or defect group. Conclusion: This study demonstrated that 3D printing of PEGDA/ECM hydrogel incorporating the anti-inflammatory phytomolecule honokiol could provide a promising scaffold for osteochondral defect repair.

Osteochondral Tissue Engineering: The Potential of Electrospinning and Additive Manufacturing

“…Adapted from [325] under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/). Copyright © 2019, Tamay, et al Similarly, promising results were recently achieved by Zhu and co-workers, with the use of a hybrid PEGDA/dECM 3D-printed scaffold (Figure 13a,b) loaded with honokiol, a natural polyphenol with anti-inflammatory action [329]. Upon in vivo testing over eight weeks, comparable SB repair levels were attained for unloaded and honokiol-loaded PEGDA/dECM constructs, revealing that the biomaterials alone can guide bone regeneration.…”

“…As such, AM techniques have the immeasurable potential for precision medicine, since they enable mass customisation, generation of constructs with complex geometries, and the use of multiple biomaterials with variable physicochemical properties [ 326 ]. Depending on the specific AM methodology, natural [ 327 , 328 , 329 ] and/or synthetic [ 135 , 151 ] materials, as well as ceramics or metals [ 330 , 331 ], can be used in AM as resins or inks.…”

“…Upon in vivo testing over eight weeks, comparable SB repair levels were attained for unloaded and honokiol-loaded PEGDA/dECM constructs, revealing that the biomaterials alone can guide bone regeneration. Nevertheless, the presence of honokiol proved crucial for cartilage remodelling and repair, culminating in a well-organised hyaline-like cartilaginous neotissue with stratified chondrocyte disposition close to that of native cartilage and expression of tissue-specific biochemical markers [ 329 ]. It should, however, be taken into account that the in vivo studies in both these reports were carried using rat OC defect models, in which the dimensions of the defect and the load-bearing mechanical stress differ substantially from those in a human joint.…”

Toward a Better Regeneration through Implant‐Mediated Immunomodulation: Harnessing the Immune Responses

“…Scaffold composed of decellularized cartilage ECM and PEG diacrylate integrated with honokiol was prepared through stereolithography‐based 3D printing technique. [ 262 ] In vitro data showed suppressed proinflammatory cytokines secreted from macrophages and improved new bony tissue formation was observed in a rat osteochondral defect.…”

Review on Computer-Aided Design and Manufacturing of Drug Delivery Scaffolds for Cell Guidance and Tissue Regeneration

“…Additive manufacturing techniques can be conveniently classified into discontinuous techniques, where layers’ fabrication and assembly involve two distinct processing steps, and continuous techniques, where these two steps are mostly automatized and take place at once ( Salerno et al, 2019 ). Both approaches have been used in the past years to load GFs to stimulate cell growth ( Bittner et al, 2018 ; Koons and Mikos, 2019 ); anti-inflammatories and immunomodulators were used to control in vivo body response after scaffold implantation ( Zhu et al, 2020 ); chemotherapist molecules were delivered to kill cancer cells and stop tumor progression ( Shi et al, 2020 ). As summarized in Figure 2 , loading bioactive molecules in AM scaffolds was achieved during manufacturing or by postprocessing treatments and following four main methods.…”