Effect of platelet factors and thrombin on multiplication of human bone marrow mesenchymal stem cells cultured in low and high oxygen level in vitro
Background: In the bone marrow, hematopoietic and mesenchymal stem cells form a unique niche, in which oxygen tension is low. Hypoxia may have a role in maintaining stem cell capacity for self-renewal and multipotency. We have shown previously a positive influence of platelet-derived growth factors (PDF) on increase of multiplication rate of human mesenchymal stem cells cultured in normal atmosphere. Objective: The goal of this study is to examine effects of platelet-derived factors and thrombin on multiplication of adult human mesenchymal stem cells derived from bone marrow (hBMMSC) in a low or in a high oxygen environment in vitro. Hypothesis: It is hypothesized that PDF will have no effect on multiplication of BMMSC cultured in a low oxygen environment and that thrombin will have no effect on multiplication of BMMSC in either low or high oxygen atmosphere. Materials and methods: Adult human mesenchymal stem cells isolated from bone marrow aspirate (Lonza) were used. Cells were grown in plastic flasks or dishes. The human mesenchymal stem cell basal medium (Lonza) was supplemented with adult human serum with or without PDF or with or without thrombin. High and low oxygen environment (Biospherix) was applied during expansion of hBMMSC. Results: Cultivation medium containing PDF in 5% oxygen increased multiplication rate of hBMMSC. Thrombin addition to the cultivation medium had a positive influence on cell multiplication in 21% oxygen atmosphere, but not in presence of 5% oxygen. Conclusions: PDF enhanced proliferation of hBMMSC grown in 5% oxygen when compared to controls. Thrombin had a stimulatory effect in 21% oxygen environment. These findings will be utilized in an optimized protocol used for cultivation of hBMMSC preceding their clinical application. The hBMMSC need to be grown in physiological conditions and for the shortest cultivation period possible. 6
Cellular biology, Dentistry, Biological sciences, Health and environmental sciences
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