3D Bioprinted Silk‐Based In Vitro Osteochondral Model for Osteoarthritis Therapeutics

Abstract

3D bioprinting of osteochondral tissue offers unique opportunities for enabling precise pharmacological interventions in osteoarthritis (OA). The current study investigates the screening potential of anti-inflammatory drugs using bioprinted inflamed human osteochondral units. The biomimetic hierarchical geometry is bioprinted using silk-based bioinks encapsulating pre-differentiated stem cells, creating an in vitro model. Inflammation is stimulated in the model, using tumor necrosis factor-alpha and Interleukin-1 beta pro-inflammatory cytokines. The resultant degeneration, akin to OA, is flagged by key markers like sulfated glycosaminoglycan, collagen, alkaline phosphatase, and downregulation of osteochondral transcript levels. In the next step, the screening of anti-inflammatory drugs is validated using celecoxib and rhein. Consequently, in the inflamed constructs, the initial upregulation of the key inflammatory mediators (nitric oxide, Prostaglandin E2), is subsequently downregulated, post-drug treatment. In addition, catabolic markers (matrix metalloproteinases and aggrecanase-1), indicative of hypertrophic and apoptosing chondrocytes, are significantly downregulated in the treatment groups; while the transcript and protein levels required for osteochondral health are attenuated. Therefore, the in vitro model mimicks the inflammation in the early stages of OA, and corroborates a potential high-throughput platform for screening novel anti-inflammatory drugs in OA therapeutics.

Bioengineering and Clinical Translation of Human Lung and its Components

“…[ 139 ] A successful tissue engineering approach can also provide physiologically‐relevant lung disease models. Animal models or human pathology specimens have formed the basis for our understanding of the pathogenesis of several diseases; however, increasing number of in vitro models using human cells have been developed and used for modeling several pathologies [ 140 ] including lung diseases. [ 141 ]…”

Keeping It Organized: Multicompartment Constructs to Mimic Tissue Heterogeneity

“…[30] In reference to the heterogeneity within complex biological systems, some of the most recent research aims to introduce different compartments or regions within a construct. [31][32][33]…”

“…This is crucial, as the use of cell-laden hydrogels as the printing component allows for the combination of polymers, ECM materials, and chemical factors to provide the entire range of cues present in native cell microenvironments (Table 1). It should be noted that [32] a minibrain with inner glioblastoma compartment surrounded by macrophages, [31] and an ex vivo glioblastoma-on-a-chip model. [49] b) Laser-assisted bioprinting: depiction of a confocal reconstruction of different layers of apical (green) and endothelial cells (red) and a crosssection illustrating different layering of constructs.…”

Biofabrication of the osteochondral unit and its applications: Current and future directions for 3D bioprinting

“…Recently, Singh et al have developed what appears to be the first 3D bioprinted osteochondral-based in vitro disease model for early OA. 90 As previously summarised in Table 1 , silk fibroin-based bioinks were used alone or combined with nHA to recreate the cartilage and bone sections of the osteochondral unit in vitro, respectively. After preconditioning hADSCs to the corresponding chondrogenic or osteogenic lineages, the cells were bioprinted and cultured in pro-inflammatory culture media for 7 days, using cytokines such as IL-1β and TNF-α.…”

“…Singh et al 90 Extrusion-based C28/I2 human chondrocyte cell line PLA + alginate 7%wt Hybrid scaffolds were developed through co-deposition of PLA and cell-laden alginate hydrogel. They achieved homogeneous cell distribution on the cartilage side and >75% cell viability.…”