Fogorvosi szemle, 2005 (98. évfolyam, 1-6. szám)

2005-04-01 / 2. szám

71

FOGORVOSI SZEMLE

recently shown to be induced in-vitro in different cancer cell-lines during hypoxia (Sirkku et al. 2002). The aim of the present study was to examine the expression of the tuftelin gene in-vivo in mouse brain and invitro in PC12 cell line during hypoxia. Methods: Quantification of the tuftelin mRNA was performed using realtime quantitative PCR (LightCycler, Roche). C57BL/6 mice were intraperitoneal injectioned with CoCI2, (mimics physiological hypoxia in animals) and the level of tuftelin mRNA expression in mouse brain was checked 12 hours after the hypoxic induction. To induce the oxygen deprivation insult, PC12 cells were introduced into a hypoxic device (1% oxygen) as previously described (Abu-Raya et al.,1999), and the levels of tuftelin mRNA expression were checked 2, 4, 6, 12 and 24 hours after the hypoxic insult. Results: The results, 12 hours after in vivo induction of chemical hypoxic conditions, tuftelin mRNA expression in the mouse brain increased significantly. In-vitro studies, using the neuronal cell line model - PC12, showed a significant increase in tuftelin expression at 12 hours, and further increase at 24 hours after hypoxic insult. Conclusion: The present results show invivo and in-vitro induction of the tuftelin gene in mouse brain and in PC12 cell line respectively, under hypoxic conditions. Reduced oxygen tension was reported to be involved in mineralization of hard tissues. The present results and ongoing structural and functional studies will contribute to the understanding of the role of tuftelin in the normal, aging and diseased brain, and possibly in cancer progression and in biomineralization of hard tissues. Keywords: Brain, neurons, tuftelin in vivo and in vitro induction, hypoxia Acknowledgement: Supported by the U.S-lsrael Binational Science Foundation No. 9800099 (D. Deutsch), COST B23 support of the meeting is recognized

P. FERRETTI AND L. SANTOS-RUIZ

Developmental Biology Unit, Institute of Child Health, University College London, London, UK

A MODEL FOR STUDYING NORMAL AND MUTATED OSTEOPROGENITORS AND THEIR POTENTIAL USE AS AUTOGRAFTS FOR CRANIAL BONE RECONSTRUCTION

The capacity of bone to heal and regenerate, particularly in the craniofacial region, is limited. Most commonly titanium cranioplasty and bone grafts are used for reconstruction of extensive cranial deficits, which do not remodel/regenerate spontaneously during the lifetime of the patient. This approach, though in some respects quite effective, does not result in proper bone repair. Particularly in the case of young individuals, such as in children with craniosynostosis, that is premature bone differentiation and fusion of cranial sutures, repeated sur-■ 98. évf. 2. sz. 2005.

gery is often required. Recently, protective sheets made of biocompatible polymers, such as polylactic acid-polyglycolic acid copolymer (PLGA), that are reabsorbed over several months after surgery, have started to be used in craniofacial surgery. However, the use of such materials alone does not appear to be sufficient to stimulate significant regeneration of cranial bone and the development of tissue engineering strategies appears to be critical for inducing extensive bone repair. Key issues in developing cell grafting strategies are the source of cells and the problem of tissue rejection. Ideally, osteoprogenitors from patients themselves should be implanted to avoid rejection. Whereas cell therapy using autografts could be applied in the case of a traumatic injury, in the case of children with syndromic craniosynostoses, osteoprogenitor cells carry the mutation that caused premature osteodifferentiation and suture fusion, and their growth and differentiation in vitro is also affected. Our aim is to select suitable bioabsorbable matrices and identify appropriate culture conditions that will allow us to efficiently grow “syndromic” osteoblasts and use them for autologous transplantation as biohybrids. The model we are currently using is the osteoblastic cell line MC3T3, originated from mouse calvarium, and MC3T3 lines carrying FGFRs with single point mutations associated with craniosynos- 1 tosis that we have recently generated. The properties of these cells and their ability to grow and differentiate on different matrices will be discussed. Acknowledgement: The support of COSTB23 is acknowledged.

S. HÄGEWALD, P. MURAWEL, J. SEYBOLD*, JP. BERNIMOULIN1

Dept, of Periodontology and *Dept. of Infectious Diseases, Charité, University Medicine Berlin, Germany.

EFFECTS OF GROWTH FACTORS AND ENAMEL MATRIX DERIVATIVE ON MRNA EXPRESSION OF MINERALIZATION MARKERS IN PDL AND MC3T3 CELLS

! Background: Growth factors from thrombocytes and

; enamel matrix derivative (EMD) are possible stimulators of growth and differentiation of periodontal cells. However, the molecular mechanisms are only partially known. The purpose of this study was to determine their effects on mRNA expression of mineralization markers.

Methods: Human periodontal ligament (PDL) cells from root surfaces of extracted teeth and mouse embryo calvaria fibroblasts (MC3T3-E1) were grown for 5,12 and 16 days. Both cell types were stimulated with endogenous growth factors (prepared by PRGF procedure, Wieland, Germany) or with EMD (Emdogain®, Straumann, Switzerland). Cultures with 2% or 10% FCS served as controls. The expression of mRNA of markers for periodon-