Abstract
BackgroundNotochordal cell conditioned medium (NCCM) derived from non-chondrodystrophic dogs has pro-anabolic and anti-catabolic effects upon nucleus pulposus (NP) cells. Here, for the first time, we assessed the ability of NCCM to influence the production of extracellular matrix and inflammatory proteins by healthy and osteoarthritic human chondrocytes within engineered cartilage tissues. We hypothesized that, similar to its action on NP cells, NCCM exerts metabolic and anti-catabolic effects on human articular chondrocytes and has the potential to significantly counteract inflammatory mediators.MethodsChondrocytes from nine non-osteoarthritic patients and from six osteoarthritic (OA) donors at the time of total knee arthroplasty were chondro-differentiated in pellets for 2 weeks. Non-OA pellets were exposed for 72 hours to IL-1β/TNF-α and then cultured up to 14 days in 2 % FBS-supplemented NCCM or 2 % FBS-supplemented medium (control (ctr)). OA pellets were cultured in NCCM or ctr medium without pro-inflammatory treatment. Tissues after each culture phase were analyzed biochemically (GAG/DNA), (immuno-) histologically (collagen I, II and GAG) and by Western blotting. Supernatants were analyzed by ELISA.ResultsResponse to NCCM was age and disease dependent with healthy chondrocyte pellets (from donors >55 years of age) recovering their glycosaminoglycan (GAG) contents to baseline levels only with NCCM. OA pellets treated with NCCM significantly increased GAG content (1.8-fold) and levels of hyaluronic acid link protein (HAPLN), fibromodulin and SOX-9. The catabolic proteins (matrix metalloproteinase (MMP)-3 and MMP-13) and pro-inflammatory enzyme levels (cyclooxygenase-2 (COX-2)) were markedly reduced and there was significantly reduced secretion of pro-inflammatory chemokines (IL-6 and IL-8).ConclusionsNCCM restores cartilage matrix production of end-stage human OA chondrocytes towards a healthy phenotype and suppresses the production of inflammatory mediators. Harnessing the necessary and sufficient factors within NCCM that confers chondroprotection and regenerative effects could lead to a minimally invasive agent for treatment of degenerative and inflammatory joint diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1026-x) contains supplementary material, which is available to authorized users.
Highlights
Notochordal cell conditioned medium (NCCM) derived from non-chondrodystrophic dogs has pro-anabolic and anti-catabolic effects upon nucleus pulposus (NP) cells
We have demonstrated previously that there is considerable preservation in genomic and proteomic sequences between canine and human species in that we have determined the presence of connective tissue growth factor (CTGF) within NCCM in our first proteomic analysis of NCCM, validating that the use of cross-species conditioned medium is a valid approach [21]
Notochordal cell-rich intervertebral disc (IVD) NPs were obtained from 10 different non-chondrodystrophic canine (NCD) dogs within an age range of 12–18 months in collaboration with a licensed animal facility and all practices were in accordance with the animal care policies and ethics approval board of The University Health Network, Toronto, Ontario, Canada
Summary
Notochordal cell conditioned medium (NCCM) derived from non-chondrodystrophic dogs has pro-anabolic and anti-catabolic effects upon nucleus pulposus (NP) cells. Consistent with its participation in development, cartilage and the notochord express a number of similar genes as those that encode type II and type IX collagen, aggrecan, SOX-9 and chondromodulin, suggesting that these cells may have conserved common physiological properties [8,9,10,11,12]. These common features, taken together with previous work, suggest that the soluble factors secreted by notochordal cells may confer anabolic and anticatabolic effects upon cartilage
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