Conditioned medium as a strategy for human stem cells chondrogenic differentiation

Paracrine signalling from chondrocytes has been reported to increase the synthesis and expression of
cartilage extracellular matrix (ECM) by stem cells. The use of conditioned medium obtained from
chondrocytes for stimulating stem cells chondrogenic differentiation may be a very interesting
alternative for moving into the clinical application of these cells, as chondrocytes could be partially
replaced by stem cells for this type of application. In the present study we aimed to achieve
chondrogenic differentiation of two different sources of stem cells using conditioned medium,
without adding growth factors. We tested both human bone marrow-derived mesenchymal stem cells
(hBSMCs) and human Wharton’s jelly-derived stem cells (hWJSCs). Conditioned medium obtained
from a culture of human articular chondrocytes was used to feed the cells during the experiment.
Cultures were performed in previously produced three-dimensional (3D) scaffolds, composed of a
blend of 50:50 chitosan:poly(butylene succinate). Both types of stem cells were able to undergo
chondrogenic differentiation without the addition of growth factors. Cultures using hWJSCs showed
significantly higher GAGs accumulation and expression of cartilage-related genes (aggrecan, Sox9
and collagen type II) when compared to hBMSCs cultures. Conditioned medium obtained from
articular chondrocytes induced the chondrogenic differentiation of MSCs and ECM formation.
Obtained results showed that this new strategy is very interesting and should be further explored
for clinical applications