Characterization of the cells in repair tissue following autologous chondrocyte implantation in mankind: a novel report of two cases

AIM: Autologous chondrocyte implantation (ACI) is used worldwide for the treatment of cartilage defects. This study has aimed to assess for the first time the cells that are contained within human ACI repair tissues several years post-treatment. We have compared the phenotypic properties of cells from within the ACI repair with adjacent chondrocytes and subchondral bone-derived mesenchymal stromal/stem cells (MSCs). MATERIALS & METHODS: Two patients undergoing arthroplasty of their ACI-treated joint were investigated. Tissue and cells were isolated from the repair site, adjacent macroscopically normal cartilage and MSCs from the subchondral bone were characterized for their growth kinetics, morphology, immunoprofile and differentiation capacity. RESULTS: ACI repair tissue appeared fibrocartilaginous, and ACI repair cells were heterogeneous in morphology and size when freshly isolated, becoming more homogeneous, resembling chondrocytes from adjacent cartilage, after culture expansion. The same weight of ACI repair tissue resulted in less cells than macroscopically normal cartilage. During expansion, ACI repair cells proliferated faster than MSCs but slower than chondrocytes. ACI repair cell immunoprofiles resembled chondrocytes, but their differentiation capacity matched MSCs. CONCLUSION: This novel report demonstrates that human ACI repair cell phenotypes resemble both chondrocytes and MSCs but at different stages of their isolation and expansion in vitro

Human Articular Chondrocytes Retain Their Phenotype in Sustained Hypoxia While Normoxia Promotes Their Immunomodulatory Potential.

Objective To assess the phenotype of human articular chondrocytes cultured in normoxia (21% O2) or continuous hypoxia (2% O2). Design Chondrocytes were extracted from patients undergoing total knee replacement ( n = 5) and cultured in ~21% (normoxic chondrocytes, NC) and 2% (hypoxic chondrocytes, HC) oxygen in both monolayer and 3-dimensional (3D) pellet culture and compared with freshly isolated chondrocytes (FC). Cells were assessed by flow cytometry for markers indicative of mesenchymal stromal cells (MSCs), chondrogenic-potency and dedifferentiation. Chondrogenic potency and immunomodulatory gene expression was assessed in NC and HC by reverse transcription quantitative polymerase chain reaction. Immunohistochemistry was used to assess collagen II production following 3D pellet culture. Results NC were positive (>97%, n = 5) for MSC markers, CD73, CD90, and CD105, while HC demonstrated 60%) compared with HC and FC in which production was <2%. Hypoxic conditions upregulated expression of SOX9, frizzled-related protein ( FRZB), fibroblast growth factor receptor 3 ( FGFR3), and collagen type II ( COL2A1) and downregulated activin receptor-like kinase 1 ( ALK1) in 3 out of 4 patients compared with normoxic conditions for monolayer cells. Conclusions Hypoxic conditions encourage retention of a chondrogenic phenotype with some immunomodulatory potential, whereas normoxia promotes dedifferentiation of chondrocytes toward an MSC phenotype with loss of chondrogenic potency but enhanced immunomodulatory capacity

Human Mesenchymal Stromal Cells Enhance Cartilage Healing in a Murine Joint Surface Injury Model

Funding: This research was funded by Versus Arthritis, grant numbers 18480, 19429 and 21156, and the Medical Research Council, grant number MR/L010453/1. Acknowledgments: We thank Pat Evans and Martin Pritchard, Histopathology Dept, RJAH Orthopaedic Hospital, for guidance on histology; Meso Scale Diagnostics, LLC for advice and the loan of equipment for analyte analyses; all members of the Arthritis and Regenerative Medicine Laboratory at the University of Aberdeen, particularly Hui Wang, Sharon Ansboro and Ausra Lionikiene for their help with mouse surgeries and tissue collection, as well as staff at the University of Aberdeen’s animal facility and microscopy and hystology facility for their supportPeer reviewedPublisher PD

The Up-Scale Manufacture of Chondrocytes for Allogeneic Cartilage Therapies

Background: Allogeneic chondrocyte therapies need to be developed to allow more individuals to be treated with a cell therapy for cartilage repair and to reduce the burden and cost of current two-stage autologous procedures. Up-scale manufacture of chondrocytes using a bioreactor could help provide an off-the-shelf allogeneic chondrocyte therapy with many doses being produced in a single manufacturing run. Here we assess a Good Manufacturing Practice compliant hollow-fibre bioreactor (Quantum®) for adult chondrocyte manufacture. Methods: Chondrocytes were isolated from knee arthroplasty derived cartilage (n=5) and expanded in media supplemented with 10% fetal bovine serum (FBS) or 5% human platelet lysate (hPL) on tissue culture plastic (TCP) for a single passage. hPL supplemented cultures were then expanded in the Quantum® bioreactor for a further passage. Matched, parallel cultures in hPL or FBS were maintained on TCP. Chondrocytes from all culture conditions were characterised in terms of growth kinetics, morphology, immunoprofile, chondrogenic potential (chondrocyte pellet assays) and single telomere length analysis. Results: Quantum® expansion of chondrocytes resulted in 86.4±38.5x106 cells in 8.4±1.5 days, following seeding of 10.2±3.6 x106 cells. This related to 3.0±1.0 population doublings in the Quantum® bioreactor, compared with 2.1±0.6 and 1.3±1.0 on TCP in hPL and FBS supplemented media, respectively. Quantum® and TCP expanded cultures retained equivalent chondropotency and mesenchymal stromal cell markers immunoprofiles, with only integrin marker, CD49a, decreasing following Quantum® expansion. Quantum® expanded chondrocytes demonstrated equivalent chondrogenic potential (as assessed by ability to form and maintain chondrogenic pellets) with matched hPL TCP populations. hPL manufacture however, led to reduced chondrogenic potential and increased cell surface positivity of integrins CD49b, CD49c and CD51/61 compared with FBS cultures. Quantum® expansion of chondrocytes did not result in shortened 17p telomere length when compared with matched TCP cultures. Discussion: This study demonstrates that large numbers of adult chondrocytes can be manufactured in the Quantum® hollow-fibre bioreactor. This rapid, up-scale expansion, does not alter chondrocyte phenotype when compared with matched TCP expansion. Therefore, the Quantum® provides an attractive method of manufacturing chondrocytes for clinical use. Media supplementation with hPL for chondrocyte expansion may, however, be unfavourable in terms of retaining chondrogenic capacity

From the Sum of Near-Zero Energy Buildings to the Whole of a Near-Zero Energy Housing Settlement: The Role of Communal Spaces in Performance-Driven Design

Almost a century ago Modernism challenged the structure of the city and reshaped its physical space in order to, amongst other things, accommodate new transportation infrastructure and road networks proclaiming the,nowadays much-debated ‘scientificated’ pursuit of efficiency for the city. This transformation has had a great impact on the way humans still design, move in, occupy and experience the city. Today major cities in Europe, such as Paris and London, are considering banning vehicles from their historic centers. In parallel, significant effort is currently underway internationally by designers, architects, and engineers to integrate innovative technologies and sophisticated solutions for energy production, management, and storage, as well as for efficient energy consumption, into the architecture of buildings. In general, this effort seeks for new technologies and design methods (e.g., DesignBuilder with EnergyPlus simulation engine; Rhicoceros3D with Grasshopper plugin and Ecotect, Radiance and EnergyPlus tools) that would enable a holistic approach to the spatial design of Near-Zero Energy buildings, so that their ecological benefits are an added value to the architectural design and a building’s visual, and material, impact on its surrounding space. The paper inquires how the integration of such technological infrastructure and performance-orientated interfaces changes yet again the structure and form of cities, and to what extent it safeguards social rights and enables equal access to common resources. Drawing from preliminary results and initial considerations of ongoing research that involve the construction of four innovative NZE settlements across Europe, in the context of the EU-funded ZERO-PLUS project, this paper discusses the integration of novel infrastructure in communal spaces of these settlements. In doing so, it contributes to the debate about smart communities and their role in the sustainable management of housing developments and settlements that are designed and developed with the concept of smart territories