THE EFFECTS OF HYPOXIC CONDITIONS ON THE CHONDROGENIC DIFFERENTIATION OF ADIPOSE STEM CELLS
MÄNTYMAA, ANNE (2010)
2010
Biokemia - Biochemistry
Lääketieteellinen tiedekunta - Faculty of Medicine
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Hyväksymispäivämäärä
2010-02-12
Julkaisun pysyvä osoite on
https://urn.fi/urn:nbn:fi:uta-1-20344
https://urn.fi/urn:nbn:fi:uta-1-20344
Tiivistelmä
Abstract
Background and aims: Poor self-repairing is a characteristic of articular cartilage damages. Treatments are under investigation, but none has yet proven to be an ideal treatment solution. Tissue engineering offers the possibility to permanent repair or regeneration of cartilage damages. Adult stem cells can be differentiated into mesenchymal cell lineages, such as chondrocytes. High cell density, three-dimensional culture conditions and proper culture medium are known to enhance chondrogenic differentiation. Low oxygen tension is related to normal cartilage development. Therefore, it has been an interesting option when considering the factors enhancing chodrogenic differentiation. The aim of this study was to examine the effects of hypoxic conditions on chondrogenic differentiation of human derived adipose stem cells (ASCs) and to compare the effects of different culture media on differentiation.
Methods: Human ASCs were differentiated in high cell density, in chondrogenic medium with or without transforming growth factor β1 (TGF-β1), either in hypoxic or atmospheric oxygen conditions. The relative expression of the chondorogenic markers and a hypoxic cell survival marker was determined using qRT-PCR method. Cartilaginous matrix formation was evaluated by histological analysis. The degree of differentiation was compared with cells cultured in control conditions.
Results: The expression levels of typical chondrogenic genes generally increased in differentiation conditions. However, a clear difference between hypoxic and atmospheric oxygen conditions was not observed in this study. Type II collagen expression was the highest in hypoxic control conditions, as was the case for hypoxia inducible factor 1α (HIF-1α) expression. Type X collagen expression was high in the presence of TGF-β1. Cartilage-like matrix formation was demonstrated with sulphated-glycosaminoglycan (sulphated-GAG) analysis and histochemical staining. Stronger accumulation of sulphated-GAGs was observed in atmospheric oxygen conditions than in hypoxic conditions.
Conclusions: Low oxygen tension did not enhance the chondrogenic differentiation of ASCs over atmospheric oxygen conditions. However, hypoxic control conditions supported the differentiation based on the highest relative gene expression of know chondrogenic markers. Chondrogenic differentiation was evaluated to be better in atmospheric oxygen conditions than in hypoxic conditions based on sulfated-GAG -staining methods. The effects of hypoxic conditions on chondrogenic differentiation must be further studied.
Background and aims: Poor self-repairing is a characteristic of articular cartilage damages. Treatments are under investigation, but none has yet proven to be an ideal treatment solution. Tissue engineering offers the possibility to permanent repair or regeneration of cartilage damages. Adult stem cells can be differentiated into mesenchymal cell lineages, such as chondrocytes. High cell density, three-dimensional culture conditions and proper culture medium are known to enhance chondrogenic differentiation. Low oxygen tension is related to normal cartilage development. Therefore, it has been an interesting option when considering the factors enhancing chodrogenic differentiation. The aim of this study was to examine the effects of hypoxic conditions on chondrogenic differentiation of human derived adipose stem cells (ASCs) and to compare the effects of different culture media on differentiation.
Methods: Human ASCs were differentiated in high cell density, in chondrogenic medium with or without transforming growth factor β1 (TGF-β1), either in hypoxic or atmospheric oxygen conditions. The relative expression of the chondorogenic markers and a hypoxic cell survival marker was determined using qRT-PCR method. Cartilaginous matrix formation was evaluated by histological analysis. The degree of differentiation was compared with cells cultured in control conditions.
Results: The expression levels of typical chondrogenic genes generally increased in differentiation conditions. However, a clear difference between hypoxic and atmospheric oxygen conditions was not observed in this study. Type II collagen expression was the highest in hypoxic control conditions, as was the case for hypoxia inducible factor 1α (HIF-1α) expression. Type X collagen expression was high in the presence of TGF-β1. Cartilage-like matrix formation was demonstrated with sulphated-glycosaminoglycan (sulphated-GAG) analysis and histochemical staining. Stronger accumulation of sulphated-GAGs was observed in atmospheric oxygen conditions than in hypoxic conditions.
Conclusions: Low oxygen tension did not enhance the chondrogenic differentiation of ASCs over atmospheric oxygen conditions. However, hypoxic control conditions supported the differentiation based on the highest relative gene expression of know chondrogenic markers. Chondrogenic differentiation was evaluated to be better in atmospheric oxygen conditions than in hypoxic conditions based on sulfated-GAG -staining methods. The effects of hypoxic conditions on chondrogenic differentiation must be further studied.