Generation and Characterization of Osteochondral Grafts With Human Nasal Chondrocytes Marina Barandun, 1 Lukas Daniel Iselin, 1 Francesco Santini, 2 Michele Pansini, 2 Celeste Scotti, 3 Daniel Baumhoer, 4 Oliver Bieri, 2 Ueli Studler, 2 Dieter Wirz, 5,6 Martin Haug, 1 Marcel Jakob, 1 Dirk Johannes Schaefer, 1 Ivan Martin, 1 Andrea Barbero 1 * 1 Departments of Surgery and of Biomedicine, Basel University Hospital, University of Basel, Basel, Switzerland, 2 Department of Radiology, Clinic of Radiology and Nuclear Medicine, University of Basel Hospital, Basel, Switzerland, 3 I.R.C.C.S., Istituto Ortopedico Galeazzi, Milano, Italy, 4 Bone Tumor Reference Center at the Institute of Pathology, Basel University Hospital, Basel, Switzerland, 5 Laboratory for Biomechanics and Biocalorimetry, Biozentrum– Pharmazentrum, University of Basel, Basel, Switzerland, 6 Orthomerian, Gotthelfstrasse 105 4054, Basel, Switzerland Received 12 December 2014; accepted 8 February 2015 Published online 28 May 2015 in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/jor.22865 ABSTRACT: We investigated whether nasal chondrocytes (NC) can be used to generate composite constructs with properties necessary for the repair of osteochondral (OC) lesions, namely maturation, integration and capacity to recover from inflammatory burst. OC grafts were fabricated by combining engineered cartilage tissues (generated by culturing NC or articular chondrocytes – AC – onto Chondro-Gide 1 matrices) with devitalized spongiosa cylinders (Tutobone 1 ). OC tissues were then exposed to IL-1b for three days and cultured for additional 2 weeks in the absence of IL-1b. Cartilage maturation extent was assessed (immune) histologically, biochemically and by delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) while cartilage/bone integration was assessed using a peel-off mechanical test. The use of NC as compared to AC allowed for more efficient cartilage matrix accumulation and superior integration of the cartilage/bone layers. dGEMRIC and biochemical analyzes of the OC constructs showed a reduced glycosaminoglycan (GAG) contents upon IL-1b administration. Cartilaginous matrix contents and integration forces returned to baseline up on withdrawal of IL-1b. By having a cartilage layer well developed and strongly integrated to the subchondral layer, OC tissues generated with NC may successfully engraft in an inflammatory post-surgery joint environment. ß 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1111–1119, 2015. Keywords: tissue engineering; osteochondral lesion; chondrocytes; dGEMRIC; chondrogenic differentiation Trauma and disease of joints often result in damages of the articular cartilage surface and the underlying subchondral bone. Such osteochondral (OC) defects do not spontaneously heal, leading to progressive articu- lar surface damage and, ultimately, to osteoarthritic degenerative changes. 1–4 Despite various therapeutic approaches have been developed to treat OC defects, none of them have proved yet to ensure long-lasting articular surface regeneration. Autologous or allogene- ic osteochondral transplants are often considered for the treatment of OC lesions but such techniques are potentially limited by the availability of material, donor site morbidity and risk of infection. 5 The fabrication of engineered OC composites, using autolo- gous cells and suitable three-dimensional (3D) scaf- folds, would provide the possibility to repair the damaged articular joint by grafting biologically and biomechanically competent tissues, obtained with min- imal donor site morbidity. OC grafts have been mainly generated using mesenchymal stem/stromal cells (MSC) or articular chondrocytes (AC). 6 However the use of these cell sources for the fabrication of OC as graft material to treat articular defects would be hampered by the phenotypic instability of the cartilage tissue formed by MSC 7 or the large inter-donor variability in the cartilage forming capacity of AC. 8 To bypass the aforementioned critical issues, a more reproducible chondrogenic cell source should be identi- fied. As compared to AC, nasal chondrocytes (NC) were shown to have a higher capacity to generate functional cartilaginous tissues, with lower donor-related depen- dency, 9–11 and to respond similarly to AC to physical forces resembling joint loading. 12 Moreover, in a recent study, 13 we have demonstrated the molecular compati- bility of NC at an articular site, verified by pre-clinical studies in goats and by an ongoing clinical trial at the University-Hospital Basel (http://clinicaltrials.gov Identifier: NCT01605201). In addition, the use of autologous NC for generation of OC grafts would ensure minimal donor site morbidity, especially when compared to the use of autologous AC. 12,14 It has, however, not been explored yet whether NC can be used to generate composite constructs with properties enabling their utilization for the repair of OC lesions. With this goal in mind, we performed the following investigations. First, OC tissues generated by combin- ing NC or AC with biomaterials currently in clinical use 15 were compared for the amount of cartilage matrix accumulated in the chondral layer and for the extent of cartilage/bone integration. We then investi- gated how these properties were modulated by a short- term exposure to interleukin (IL)-1b, mimicking the initial inflammatory implantation site, and follow- ing a recovery time. Finally, with the perspective to monitor quantitatively the maturation of the grafts in a non-invasive manner, we assessed whether delayed gadolinium-enhanced magnetic resonance imaging of Marina Barandun, Lukas Daniel Iselin contributed equally to this work. Grant sponsor: Swiss National Science Foundation; Grant number: 310030-126965.1.  Correspondence to: Andrea Barbero (T: þ41 61 265 2379; F: þ41 61 265 3990; E-mail: Andrea.Barbero@usb.ch) # 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. JOURNAL OF ORTHOPAEDIC RESEARCH AUGUST 2015 1111