ICRS 2019 - Conference Calendar

Displaying One Session

Plaza A Special Session
Session Type
Special Session
Date
08.10.2019
Time
12:15 - 13:15
Location
Plaza A
Extended Abstract (for invited Faculty only) Culture Models

24.3.1 - Knee Joint-On-A-Chip

Presentation Number
24.3.1
Presentation Topic
Culture Models
Lecture Time
12:15 - 12:35
Session Type
Special Session
Corresponding Author

Abstract

Introduction

None of the currently available animal models is capable of capturing the full complexity of osteoarthritis in man. Organ-on-chip technology is an emerging field aiming at developing miniaturized humanized models for understanding organ function in health and disease. These humanized models are expected better predictive for human disease than animals and ultimately my reduce the need of animal testing. Various attempts are currently explored to engineer a human knee joint-on-chip. It is expected that these joint-on-chip models proof valuable in deciphering complex interactions between joint tissues in the initiation and progression of disease which cannot easily be studied in human. Furthermore they may proof highly valuable in drug development programs.

Content

But how to engineer a joint-on-chip? This effort requires a multidisciplinary approach. It requires input from typical engineering disciplines from diverse fields like microfluidics, polymer chemistry and processing and physics of fluids with life sciences. In my presentation I will highlight basic principles from organ-on-chip technologies and present our strategy to engineer a human knee joint on chip. In our strategy we first focus on the development of individual modules each representing one of the joint tissues (i.e. synovial membrane, ligament, meniscus, cartilage, bone). After extensive testing and validation, these individual modules will be combined in a new chip: the Joint-on-Chip using plug and play strategies. We have started with the engineering of a cartilage and a synovium on chip and have set out strategies for device characterization and validation. I will present new chip designs that allow actuation of cartilage on chip that faithfully mimics compression and shear stress in the knee joint. For the cartilage on chip we have developed a monolithic organ-on-a-chip platform, in which engineered cartilage tissue composed of cells within a 3D hydrogel can be exposed to multi-modal mechanical stimulation, such as uniform compression and bulk shear strain. This mechanical stimulation is achieved through deflection of a thin elastic vertical membrane, which is actuated using three independently addressed yet connected pressurized chambers. By tuning the pressure applied in the different chambers (positive vs. negative, and amplitude), a variety of programmable deflection patterns can be created and, in turn, various cell stimulation modalities. The device design and actuation parameters were optimized to produce physiologically relevant compression and shear strain on a 3D cartilage model (ca. 5-12% and ca. 10 millirad, respectively). Encapsulated chondrocytes within the platform could be intermittently stimulated to simulate human locomotion patterns for at least 3 days. Advantageously, the fabrication of this monolithic platform is straightforward, with a single-step process. I will show our efforts to characterize these designs in more detail. Furthermore, I will present data on the engineering of a synovial membrane-on-chip containing a functional innate immune system. To develop a physiological relevant membrane we started to explore the use of various polymers like PDMS, PTMC and silk fibroin which was processed using elektrospinning. We subjected each of these membranes to extensive testing and developed strategies for the incorporation of these membranes in the chip designs. Also in the synovial on chip we incorporated actuation units that could impose stress and strain on the membrane mimicking the mechanical forces exerted on the membrane during joint movement. I will show the first data with cellular responses in both chip designs.

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Extended Abstract (for invited Faculty only) Biomaterials and Scaffolds

24.3.2 - Biomaterials for Cartilage Repair: Are we Heading in the Right Direction?

Presentation Number
24.3.2
Presentation Topic
Biomaterials and Scaffolds
Lecture Time
12:35 - 12:55
Session Type
Special Session
Corresponding Author

Abstract

Introduction

Biomaterials are widely used within clinical cartilage restoration procedures and many formulations, ranging from naturally derived to fully synthetic and from soft hydrogels to hard polymers and ceramics, are currently evaluated. Biomaterial scaffolds can act as a delivery vehicle of cells and biological cues. In addition, they can provide temporal mechanical stability to aid short-term functional restoration.

This approach follows the classic principles of tissue engineering where the newly formed tissue gradually replaces the function of the (degrading) scaffolding structures. However, new data confirming old insights with respect to the inability of the collagen network, which is essential for the mechanical resilience of the cartilage tissue, to restore itself may put us back to the drawing board.

Content

Biomaterials can successfully guide and steer behavior of cells and facilitate the differentiation towards the chondrogenic lineage. A wide array of materials have been proposed and investigated1. For example, hydrogel-based materials provide a hydrated stable environment for chondrocytes to deposit an extracellular matrix that is rich in proteoglycans and collagen type II. Scaffolds derived from natural materials, such as cartilage extracellular matrix, can also provide specific biological cues to enhance matrix deposition. Synthetic thermoplastic polymers on the other hand can provide temporal mechanical stability. Driven by the complexity of the osteochondral unit, combined structures have been developed that also address the specific needs of the osteal and chondral regions. Moreover, advanced biofabrication technologies allow for the processing of a combination of multiple materials, biological cues and cells in a layer-by-layer fashion. This can assist in reproducing both the zonal organization of cartilage and the gradual transition from resilient cartilage towards the subchondral bone in biofabricated osteochondral grafts2. Mechanical characteristics, including the smoothness and low friction that are hallmarks of the articular surface, can be tuned with multi-head or hybrid printers by controlling the spatial patterning of printed structures. Moreover, these fabrication technologies can yield patient-specific implants due to their use of digital medical images. Nevertheless, current regenerative biomaterial-based approaches are based on the classic principle of tissue engineering in which the newly formed tissue gradually takes over the function of the (degrading) scaffolding structure3,4.

The specific biomechanical characteristicsof the articular cartilage are provided by the combination of the arcade-like architecture of the extracellular collagen network and the interspersed hydrophilic proteoglycan aggregates. The constitution of these “Benninghoff” arcade structures5depends on the remodeling of the deposited collagen type II fibers. It has, however, recently been shown that the collagen within the articular cartilage is, once damaged, not reconstituted to any degree in mature individuals6, confirming centuries-old observations7.Thus, the classic tissue engineering paradigm does not hold for articular cartilage.

For this reason, a paradigm shift is necessary in the field of regenerative medicine of articular cartilage and our attempts at long-term cartilage restoration will have to be redirected. Principally, there are two ways to achieve such a paradigm shift: either by recreating the tissue’s homeostatic and (epi)genetic environment as present in at the early stages of life, in which remodeling of the collagen network is still possible, or by adopting Nature’s approach in the mature individual, i.e.by creating a life-long persisting, immutable structural component of articular cartilage. Both ways face considerable challenges before they can become reality.

References

1. Hutmacher.Scaffolds in tissue engineering bone and cartilage(2000). Biomat 21(24):2529-43

2. De Ruijeret al. Simultaneous Micropatterning of Fibrous Meshes and Bioinks for the Fabrication of Living Tissue Constructs (2019). Adv Healthc Mat 8(7):e1800418

3. Langer & Vacanti. Tissue engineering (1993).Science260:920

4. Londono and Badylak. Biologic scaffolds for regenerative medicine: mechanisms of in vivo remodeling(2015). Ann Biomed Eng 43(3):577-92

5. Benninghoff. Form un Bau der Gelenkknorpel in ihren Beziehungen zur Funktion. II. Der Aufbau des Gelenkknorpels in seinen Bezeihungen zur Funktion(1925). Zeit Zellforsch und Mikroskop Anat 2:783-862.

6. Heinemeieret al. Radiocarbon dating reveals minimal collagen turnover in both healthy and osteoarthritic human cartilage (2016).Sci Transl Med 8(346):346ra90

7. Hunter, Roy Soc London, Phil Trans, 1743. 9:267

Acknowledgments

The authors would like to gratefully acknowledge funding from the European Research Council under grant agreement 647426 (3D-JOINT), Dutch Arthritis Foundation (LLP-12 and LLP-22), and the partners of ‘Regenerative Medicine Crossing Borders’ (RegMed XB), powered by Health~Holland, Top Sector Life Sciences & Health.

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Extended Abstract (for invited Faculty only) Biomaterials and Scaffolds

24.3.3 - Decellularized Tissue Derived Scaffolds for Cartilage & Osteochondral Defect Repair

Presentation Number
24.3.3
Presentation Topic
Biomaterials and Scaffolds
Lecture Time
12:55 - 13:15
Session Type
Special Session
Corresponding Author

Abstract

Introduction

Extracellular matrix (ECM) derived biomaterials are commonly used in the surgical repair of different tissues and organs [1–3]. While the exact mechanism by which these bioactive scaffolds promote regeneration remains unclear, in the early stages of healing, the ECM supports the development of a pro-regenerative immune response involving both the adaptive and the innate immune system [4]. Scaffolds used clinically are typically derived from small intestine submucosa (SIS) or pericardium, and while the ECM of these tissues clearly contain structural and regulatory biomolecules generally supportive of regeneration, it is unlikely that a single tissue source of ECM will be optimal for all clinical targets. This concept is strengthened by recent studies reporting that ECM derived biomaterials can direct the differentiation of mesenchymal stem cells (MSCs) towards the phenotype of the source tissue from which they were derived [5]. This motivates the development of tissue-specific ECM derived scaffolds, potentially consisting of different layers or lineage-specific regions, especially when attempting to regenerate complex multi-phasic tissues such as the osteochondral unit of synovial joints.

Content

We have previously used the ECM from both porcine growth plate (GP) and articular cartilage (AC) to produce scaffolds for tissue engineering, with GP derived biomaterials shown to support large bone defect healing [6], and AC derived scaffolds shown to support chondrogenesis [7,8]. This talk will describe how porous scaffolds derived from these two ECMs can support the development of distinct tissue types when seeded with mesenchymal stem cells (MSCs). Next, it will be demonstrated that a bi-phasic scaffold consisting of spatially distinct but integrated layers of GP and AC ECM can be used to spatially direct MSC differentiation in vitro. It will also be demonstrated that such scaffolds support joint regeneration in vivo when implanted into critically-sized osteochondral defects in skeletally mature goats. Finally, this talk will describe how ECM derived scaffolds can be combined with 3D printed biomaterials to develop novel implants for the regeneration of focal chondral defects.

References

[1] T.W. Gilbert, T.L. Sellaro, S.F. Badylak, Decellularization of tissues and organs, Biomaterials. 27 (2006) 3675–3683. doi:10.1016/j.biomaterials.2006.02.014.

[2] K.E.M. Benders, P.R. van Weeren, S.F. Badylak, D.B.F. Saris, W.J.A. Dhert, J. Malda, Extracellular matrix scaffolds for cartilage and bone regeneration, Trends Biotechnol. 31 (2013) 169–176. doi:10.1016/j.tibtech.2012.12.004.

[3] S.F. Badylak, Xenogeneic extracellular matrix as a scaffold for tissue reconstruction, Transpl. Immunol. 12 (2004) 367–377. doi:10.1016/j.trim.2003.12.016.

[4] J.L. Dziki, L. Huleihel, M.E. Scarritt, S.F. Badylak, Extracellular Matrix Bioscaffolds as Immunomodulatory Biomaterials, Tissue Eng. Part A. 23 (2017) 1152–1159. doi:10.1089/ten.tea.2016.0538.

[5] K. Shimomura, B.B. Rothrauff, R.S. Tuan, Region-Specific Effect of the Decellularized Meniscus Extracellular Matrix on Mesenchymal Stem Cell–Based Meniscus Tissue Engineering, Am. J. Sports Med. 45 (2017) 604–611. doi:10.1177/0363546516674184.

[6] G.M. Cunniffe, P.J. Díaz-Payno, J.S. Ramey, O.R. Mahon, A. Dunne, E.M. Thompson, F.J. O’Brien, D.J. Kelly, Growth plate extracellular matrix-derived scaffolds for large bone defect healing, Eur. Cell. Mater. 33 (2017) 130–142. doi:10.22203/eCM.v033a10.

[7] H. V Almeida, G.M. Cunniffe, T. Vinardell, C.T. Buckley, F.J. O’Brien, D.J. Kelly, Coupling freshly isolated CD44(+) infrapatellar fat pad-derived stromal cells with a TGF-β3 eluting cartilage ECM-derived scaffold as a single-stage strategy for promoting chondrogenesis, Adv. Healthc. Mater. 4 (2015) 1043–53. doi:10.1002/adhm.201400687.

[8] H. V. Almeida, R. Eswaramoorthy, G.M. Cunniffe, C.T. Buckley, F.J. O’Brien, D.J. Kelly, Fibrin hydrogels functionalized with cartilage extracellular matrix and incorporating freshly isolated stromal cells as an injectable for cartilage regeneration, Acta Biomater. 36 (2016) 55–62. doi:10.1016/j.actbio.2016.03.008.

Acknowledgments

Funding for this study was provided by the European Research Council Starter Grant (StemRepair – Project number: 258463), Science Foundation Ireland (SFI/12/RC/2278; 12/IA/1554) and Enterprise Ireland (CF/2014/4325)

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