Nose to back: compatibility of nasal chondrocytes with environmental conditions mimicking a degenerated intervertebral disc.

Nasal chondrocytes (NCs) have gained increased recognition for cartilage tissue regeneration. To assess NCs as a source for cell therapy treatment of intervertebral disc (IVD) degeneration, tissue-forming properties of NCs under physiological conditions mimicking the degenerated IVD were compared to those of mesenchymal stromal cells (MSCs) and articular chondrocytes (ACs), two cell sources presently used in clinical trials. Cells were cultured in a combination of low glucose, hypoxia, acidity and inflammation for 28 d. Depending on the conditions, cells were either cultured in the absence of instructive growth factors or underwent chondrogenic instructional priming by addition of transforming growth factor β1 (TGFβ1) for the first 7 d. Histology, immunohistochemistry, biochemistry, enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) analyses demonstrated limited cell maintenance and accumulation of cartilaginous extracellular matrix for MSCs in IVD conditions. ACs maintained a steady accumulation of glycosaminoglycans (GAGs) throughout all non-acidic conditions, with and without priming, but could not synthesise type II collagen (Col2). NCs accumulated both GAGs and Col2 in all non-acidic conditions, independent of priming, whereas MSCs strongly diminished their GAG and Col2 accumulation in an inflamed environment. Supplementation with inflammatory cytokines or an acidic environment affected NCs to a lower extent than ACs or MSCs. The data, overall indicating that in an inflamed IVD environment NCs were superior to ACs and MSCs, encourage further assessment of NCs for treatment of degenerative disc disease.