Fogorvosi szemle, 2005 (98. évfolyam, 1-6. szám)
2005-04-01 / 2. szám
68 FOGORVOSI SZEMLE I. BINDERMAN*, H. BAHAR*, M. SCHEINOWITZ**, G. PEREZ** School of Dental Medicine*, the Neufeld Cardiac Research Institute "Department of Biomedical Engineering, Tel-Aviv University**. EXERCISE TRAINING IS STIMULATING THE REGENERATIVE CAPACITY OF MARROW TISSUE IN AGED ANIMALS Introduction: In adult life, stem cells accumulate mainly in the bone marrow, though in small quantities. These stem cells have the potential to proliferate and differentiate into several cell types and tissues. We have recently developed an in vivo model at ectopic sites of the rat to study regeneration of bone including angiogenesis. The model consists of a demineralized rat femur cylinder (DBM-demineralized bone matrix) into which fresh marrow of the same strain of rats is placed. These DBM cylinders including the marrow are implanted at thoracic subcutaneous sites in 2-month old rats. We have demonstrated that an ‘ossicle’, typical for long bones develops including novel bone marrow, 3 to 4 weeks after implantation. When one year old rats were used as donors of bone marrow, bone failed to develop in the young recipient rats. Aim: To investigate the effect of exercise training on the capability of bone marrow, obtained from prior-trained old donor animals, to stimulate new bone growth in young recipient animals. Methods: One-year old female rats (n=3) underwent 2 weeks of voluntary running activity exercise training. Demineralized rat femur bones (DBM) were filled with bone marrow obtained from exercise trained animals, as described above. Rats were sacrificed 11 and 21 days after implantation, and the cylinders were removed for histological and microradiographic analyses. Results: Exercise training produced a strong regenerative capacity of the marrow showing numerous areas of bone formation even at 11 days and ossicles developed at 21 days. No bone formation was seen when untrained bone marrow was explanted. Also, high number of blood vessels (101 ±71 vs. 74±59, for trained and untrained, respectively), and the formation of arterioles covered with smooth muscle cells was observed. In contrast, the marrow from sedentary animals showed loose connective tissue and poor, delayed tissue differentiation. Conclusion: These data emphasize the significance of exercise training in stimulating the regenerative capacity of marrow tissue in aged animals. Acknowledgement: The support of COSTB23 is gratefully acknowledged. ■ 98. évf. 2. sz. 2005. D.D. BOSSHARDT, A. SCULEAN, N.P. LANG School of Dental Medicine, University of Berne, Switzerland ENAMEL MATRIX PROTEINS AND TISSUE ENGINEERING Experimental studies have shown that periodontal regeneration is achievable. However, predictability is low and the amount of newly formed tissues is not satisfying. The limitations of periodontal regeneration largely depend on the regenerative potential at the root surface. Cellular intrinsic fiber cementum, so-called bone-like tissue, may form instead of the desired acellular extrinsic fiber cementum, and tissue adherence to the treated root surface appears to be poor. Various growth factors have been evaluated for their clinical application to predictably achieve periodontal regeneration. The only commercial product available and in clinical use is an enamel matrix derivative (EMD). The rationale for using EMD as a therapeutic agent bases on the assumption that enamel matrix proteins specifically induce the formation of acellular extrinsic fiber cementum, which is indispensable for tooth anchorage. However, in most studies of diseased and EMD-treated root surfaces, the mineralized tissue that formed on the root surface is a cellrich bone-like tissue that resembles cellular intrinsic fiber cementum. While evidence for a causal connection between enamel matrix proteins and cementogenesis is lacking, the chondrogenic and osteogenic capacity of enamel matrix proteins is known for a long time. Moreover, also EMD shows osteogenic effects. Therefore, a major issue in the field of hard tissue engineering is to find out whether and in what form EMPs can be used to specifically induce the formation of cementum or bone. Keywords: enamel matrix proteins, tissue engineering Acknowledgement: Clinical Research Foundation (CRF), University of Berne, Switzerland. IR. ZERBO, ALJJ. BRONCKERS, A. DE BOER, GL. DELANGE, SA. ZIJDERVELD, CM. TEN BRUGGENKATE, EH. BURGER Dept Oral Cell Biology ACTA, van der Boechorststr 7, 1081 BT Amsterdam, The Netherlands. HISTOMORPHOMETRY OF HUMAN SINUS FLOOR AUGMENTATION USING A POROUS BETATRICALCIUM PHOSPHATE We examined the use of a porous beta-tricalcium phosphate (TCP, Cerasorb®) in a split mouth model for sinus floor augmentation prior to placement of oral dental implants. Five patients were treated bilaterally receiv-
