Induction of endostatin expression in meniscal fibrochondrocytes by co-culture with endothelial cells.
BACKGROUND
The ultimate goal after meniscus damage is the preservation of the original meniscal tissue, which is often impossible due to the limited healing capacity of meniscal lesions, especially in the avascular zone. Factors produced by endothelial cells of meniscal vessels may contribute to better wound healing in vascularized zones. We therefore investigated the expression of different angiogenic factors, growth hormones and cytokines in human fibrochondrocytes and in fibrochondrocytes upon co-culture with endothelial cells, to examine mechanisms of repair of meniscal injury in more detail and to investigate the potential use of endothelial cells in co-cultures for autologous meniscal repair utilizing tissue engineering technology.


METHODS
Gene expression of SMAD-4, iNOS, IL-1beta, VEGF, MMP-1, MMP-3, MMP-13, aggrecan, biglycan, vimentin, collagen-I, -II, -III, -IV, -VI, -X, -XVIII, angiopoietin-1, angiopoietin-2, and thrombostatin-1 were investigated in fibrochondrocytes in comparison to cells in co-culture with human umbilical vein endothelial cells (HUVEC). The expression of endostatin was enumerated in cell supernatants. A proliferation assay was used to investigate the mitotic activity of the cells.


RESULTS
In presence of HUVEC, meniscal fibrochondrocytes expressed SMAD-4, iNOS, IL-1beta, VEGF, MMP-1, MMP-3, MMP-13, aggrecan, biglycan, vimentin, collagen-I, -II, -III, -VI, and -XVIII at rates comparable to cells without HUVECs. Note that the expression of endostatin was significantly higher in the co-culture when compared to the separate fibrochondrocyte cultures and the proliferation rate of endothelial cells was significantly decreased in co-culture.


CONCLUSIONS
We conclude that the expression of the anti-angiogenic factor endostatin increased in the fibrochondrocytes. This may limit the regeneration capacities of meniscal injury in vivo.
Department of Orthopaedic Surgery and Traumatology, Hospital rechts der Isar, Technical University of Munich, Ismaninger, Strasse 22, 81675, Munich, Germany. maik.hoberg@lrz.tum.de
Maik
M
Hoberg
Edda L
EL
Schmidt
Melanie
M
Tuerk
Viviane
V
Stark
Wilhelm K
WK
Aicher
Maximilian
M
Rudert
D049109:Cell Proliferation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D043169:Endostatins / Q000096:biosynthesis*; D042783:Endothelial Cells; D006801:Humans; D008592:Menisci, Tibial / Q000378:metabolism / Q000502:physiology*; D012038:Regeneration / Q000502:physiology*; D014471:Umbilical Veins / Q000166:cytology
D043169:Endostatins