Bone marrow contains cell type termed mesenchymal stem cells (MSC), first recognized in bone marrow by a German pathologist, Julius Cohnheim in 1867. That MSCs have potential to differentiate in vitro in to the various cells lines as osteoblast, chondroblast, myoblast and adipoblast cells lines. Aims of our study were to show in vivo capacity of bone marrow MSC to produce bone in surgically created non critical size mandible defects New Zeland Rabbits, and then in second part of study to isolate in vitro MSC from bone marrow, as potential cell transplantation model in bone regeneration. In vivo study showed new bone detected on 3D CT reconstruction day 30, on all 3 animals non critical size defects, treated with bone marrow MSC exposed to the human Bone Morphogenetic Protein 7 (rhBMP-7). Average values of bone mineral density (BMD), was 530 mg/cm3, on MSC treated animals, and 553 mg/cm3 on control group of 3 animals where non critical size defects were treated with iliac crest autologue bone graft. Activity of the Alkaline Phosphatase enzyme were measurement on 0.5, 14, 21, 30 day and increased activity were detected day 14 on animals treated with bone marrow MSCs compared with day 30 on iliac crest treated animals. That results indicates strong osteoinduction activity of the experimental bone marrow MSCs models exposed to the rhBMP-7 factor Comparing ALP activity, that model showed superiorly results than control group. That result initiates us in opinion that MSCs alone should be alternative for the autolologue bone transplantation and in vitro study we isolated singles MSCs from the bone marrow of rat's tibia and femora and cultivated according to the method of Maniatopoulos et all. The small initial colonies of fibroblast like cells were photo-documented after 2 days of primary culture. Such isolated and cultivated MSCs in future studies will be exposed to the growth factors to differentiate in osteoblast and indicate their clinically potential as alternative for conventional medicine and autologue bone transplantation. That new horizons have potential to minimize surgery and patient donor morbidity, with more success treatment in bone regenerative and metabolism diseases.

OBJECTIVE To obtain information on the feasibility of employing recombinant human bone morphogenetic protein-7 (rhBMP-7), mixed with bone marrow as a substitute for autologous bone graft. METHODS We carried out the study in the University Clinic Center, Sarajevo, Bosnia and Herzegovina, from February 2002 to January 2004. Six New Zealand rabbits underwent hemiresection of the mandible. We placed rhBMP-7 in a concentration of 100 micrograms and collagen (ACS) as carrier mixed with bone marrow in the defects in 3 animals. In another group of 3, we restored the defect by placement of autologous bone graft harvested from the iliac crest. We evaluated the results by the activity of the alkaline phosphatase enzyme (ALP), CT assessment with bone mineral density (BMD) analysis, and clinical and histologic examinations. RESULTS The ALP activity was significantly higher after 14 days, in the rhBMP7/ACS sites than the bone graft sites (30th day). Mean BMD of tissue induced by rhBMP-7/ACS on the 30th day was 510 mg/cm3 in caudal, and 553 mg/cm3 in sagittal plane, and bone graft tissue was 510 mg/cm3 in caudal and 530 mg/cm3 in sagittal plane. Clinical inspection and histologic examination on the 60th day showed complete bridged defects with abundant woven bone in 2 of 3 rhBMP-7/ACS sites (67%), and no incorporation of the autologous bone graft into the other groups treated sites. CONCLUSION The rhBMP-7/ACS mixed with bone marrow was very effective in establishing complete bone regeneration into the defects, indicating that it could be an adequate alternative for autologous bone transplantation.