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Adhesion, growth and osteogenic differentiation of human bone marrow mesenchymal stem cells on positively and negatively charged and uncharged ferroelectric crystal surfaces

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Vandrovcova M. , Bacakova L. , Vanek P. , Petzelt J.

tom Vol. 19, no. 135

2--7

The cell-material interaction is significantly influenced by the physicochemical properties of the material surface, including its electrical charge. In this study, the effect of the surface polarity of ferroelectric LiNbO3 single crystals on the adhesion, growth and osteogenic differentiation of human bone marrow mesenchymal stem cells was investigated. The cells were cultured on the normal-to-plane poled and in-plane poled plates resulting in positive, negative and zero surface charge. The number of initially adhering cells on day 1 after seeding, their spreading, shape, and their metabolic activity, production of type I collagen, activity of alkaline phosphatase and mineralization in the following days of cultivation (days 6 and 20) were comparable on all three tested surfaces. However, significant differences were found in the expression of mRNA for type I collagen, alkaline phosphatase and osteocalcin, i.e. an early, medium-term and late arkers of osteogenic cell differentiation, respectively. On day 20, the expression of type I collagen was significantly lower in cells on negatively-charged than on non-charged surfaces. Moreover, the expression of alkaline phosphatase and osteocalcin was higher in cells on positively-charged than on negatively-charged surfaces. These differences were generally more pronounced in standard cell culture medium than in osteogenic medium, which could, at least partly, mask the influence of the material surface properties on the cell behaviour. Thus, positively-charged LiNbO3 surfaces seemed to be more suitable for the osteogenic differentiation of bone marrow mesenchymal stem cells than the negatively-charged surfaces.

Seasonal changes in phytoplankton composition and diversity in the Epe Lagoon, Nigeria

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Nwankwo D. I.

nr 2

Contents of total and protein-bound carbohydrates are low in leukemic leucocytes from patients with acute myelogenous leukemia

80%

Smolenska-Sym G. , Zdebska E. , Golaszewska E. , Wozniak J. , Durzynski T. , Maj S. , Mokras U. , Koscielak J.

nr 2

Leukemic leukocytes from 12 patients with acute myelogenous leukemia (AML) and two patients with chronic myelogenous leukemia (CML) were isolated by centrifugations in Percoll gradients, and examined for total carbohydrates. In leukemic leukocytes from 10 of these patients ceramide-bound carbohydrates were also determined. Protein-bound carbohydrates were calculated by subtraction of ceramide-bound carbohydrates from total carbohydrates. In all samples analysed the contents of total and protein-bound carbohydrates were much lower in leukemic leukocytes than in normal neutrophils, irrespective whether the results were expressed relative to protein, DNA, cell number or dry mass. For immature leukemic cells of MO-M1 phenotype differences up to 10-fold were observed. Contents of ceramide-bound carbohydrates, i.e. those of neutral and acidic glycosphingolipids (GSLs) were also low in leukemic cells. However, when GSL carbohydrates were calculated as percentage of total carbohydrates, GSLs in leukemic leukocytes were elevated in half of the AML patients but depressed in the other half. The results are discussed in the light of the hypothesis on GSL function by one of us (Kościelak J., 1986, Glycoconjugate J. 3, 95-108). According to one element of the hypothesis, during cell differentiation newly synthesized glycoproteins (GPs) that perform specific functions are added to house-keeping GPs that are present in plasma membranes of all types of cells. Thus, during differentiation, the GP content of the cell membrane should increase and that of the so called "membrane packing" glycosphingolipids should decrease.