Improvement of In Vitro Three-Dimensional Cartilage Regeneration by a Novel Hydrostatic Pressure Bioreactor

Abstract

In vitro three‐dimensional (3D) cartilage regeneration is a promising strategy for repair of cartilage defects. However, inferior mechanical strength and tissue homogeneity greatly restricted its clinical translation. Simulation of mechanical stress through a bioreactor is an important approach for improving in vitro cartilage regeneration. The current study developed a hydrostatic pressure (HP) bioreactor based on a novel pressure‐transmitting mode achieved by slight deformation of a flexible membrane in a completely sealed stainless steel device. The newly developed bioreactor efficiently avoided the potential risks of previously reported pressure‐transmitting modes and simultaneously addressed a series of important issues, such as pressure scopes, culture chamber sizes, sealability, contamination control, and CO2 balance. The whole bioreactor system realized stable long‐term (8 weeks) culture under high HP (5–10 MPa) without the problems of medium leakage and contamination. Furthermore, the results of in vitro 3D tissue culture based on a cartilage regeneration model revealed that HP provided by the newly developed bioreactor efficiently promoted in vitro 3D cartilage formation by improving its mechanical strength, thickness, and homogeneity. Detailed analysis in cell proliferation, cartilage matrix production, and cross‐linking level of collagen macromolecules, as well as density and alignment of collagen fibers, further revealed the possible mechanisms that HP regulated in vitro cartilage regeneration. The current study provided a highly efficient and stable bioreactor system for improving in vitro 3D cartilage regeneration and thus will help to accelerate its clinical translation. Stem Cells Translational Medicine 2017;6:982–991

A Guide for Using Mechanical Stimulation to Enhance Tissue-Engineered Articular Cartilage Properties

“…HP bioreactors have a fluid-filled chamber and a piston that applies pressure to the chamber and subsequently the tissue. [92][93][94][95] Research has focused on stimulating TEAC with HP at magnitudes ranging from 3 to 18 MPa and in general should not exceed 30 MPa because it alters chondrocyte proteoglycan synthesis. 90,92,96 Both passive and dynamic (up to 1 Hz) HPs have been investigated, yielding improved mechanical properties, ECM protein expression, and ECM content.…”

Compressive mechanical stress enhances susceptibility to interleukin-1 by increasing interleukin-1 receptor expression in 3D-cultured ATDC5 cells

“…Mechanical signal transduction appears to be triggered by a diverse array of biophysical conditions, such as cell deformation [ 52 ], alternation of hydrostatic pressure [ 53 ], fluid flow [ 54 ], and changes in extra- or intracellular osmotic pressure [ 55 ]. Numerous studies dealing with mechanotransduction in cartilage have introduced cyclic tensile stress in the monolayer culture and hydrostatic pressure in 3D culture [ 56 , 57 ]. The former experimental condition of tensile mechanical stress applied on a monolayer culture potentially causes dedifferentiation of chondrocytes.…”

4-Axis printing microfibrous tubular scaffold and tracheal cartilage application

“…Content of total collagen in different groups was quantified by a hydroxyproline assay. Samples were prepared by alkaline hydrolysis and free hydro-xyproline hydrolyzates were assayed according to a previously described method [29].…”