Georgi - Lipids as Mediators of Chondrogenesis

N. Georgi, B. Cillero Pastor, G. Eijkel, P.C. Periyasamy, A. Kiss, C. van Blitterswijk, J.N. Post, R. Heeren, M. Karperien

OARSI 2014


We have previously demonstrated that cartilage matrix formation is improved in pellet co-cultures of human mesenchymal stromal/stemcells (MSCs) and human primary chondrocytes (hPCs) under normoxic culture
conditions (21% O2). This co-culture effect is attributed to the MSC specific
expression of FGF-1. Under hypoxic culture conditions (2.5% O2), we
observed that there was a decrease in chondrogenic differentiation in co-
cultures as compared to the normoxic culturing conditions. For clinical
applications it is plausible that cotransplantation of MSCs and chondrocytes
into the defect results in improved cartilage repair. Until now it remains
unclear how FGF-1 expression is regulated under the reduced oxygen level
normally present in the joint. It has been underlined that hypoxia (reduced
oxygen availability) and expression of hypoxia-inducible factor 1 (HIF-1) are essential in maintaining cartilage homeostasis. Moreover, it has been shown that primary chondrocytes perform better under reduced oxygen levels. However, only limited research has been performed to understand how hypoxia in the joint environment might influence cellular performance. Differential expression of proteins, lipids and other components indicate the
unique behaviour of cells under different environmental conditions. In this
study we aimed to identify the mechanism leading to the loss of co-
cultureeffect under hypoxic conditions.