The population of human bone marrow mesenchymal stem cells supplemented with basic fibroblast growth factor for chondrogenic differentiation

s / Osteoarthritis and Cartilage 23 (2015) A82eA416 A382 as meniscal progenitor cells (MPC) derived from diseased human meniscus. Also osteoarthritic cartilage of DDR-1-deficient mice harbors a progenitor cell population. Conclusions: Taken together, we propose that specific progenitor cell populations found in situ are responsible for tissue regeneration in a wide variety of cartilage tissues in humans andwill be of importance for cell biological therapeutic interventions in osteoarthritis. 634 THE POPULATION OF HUMAN BONE MARROWMESENCHYMAL STEM CELLS SUPPLEMENTED WITH BASIC FIBROBLAST GROWTH FACTOR FOR CHONDROGENIC DIFFERENTIATION H. Mera yz, Y. Tamamura y, M. Itokazu yx, M. Asada y, S. Wakitani k. yMukogawa Women's Univ., Nishinomiya, Japan; z Intl. Med. Device Alliance, Fndn. for BioMed. Res. and Innovation, Kobe, Japan; xOsaka City Univ., Osaka, Japan; kDept. of Artificial Joint & Biomaterials, Hiroshima Univ. Graduate Sch. of BioMed. Sci., Hiroshima, Japan Purpose:We are studying the cell basedand pharmaceuticalapproaches for cartilage repair, combined with surgical bone marrow stimulation technique to supply the cells contributing to wound heal. Bone marrow tissue has heterogeneous cell-populations, including hematopoietic stem cells, and we prefer to enhance the cells with as better chondrogenic ability as possible in order to promote cartilage repair process. It has been known that direct intra-articular injection of basic fibroblast growth factor (bFGF) promotes articular cartilage repair of osteochondral defect in animal model, however bFGF also has an unfavorable action for clinical application, osteophyte formation. In vitro studies have shown that the supplementation of bFGF for human bone marrow derived mesenchymal stem cells (hBMSCs) during expansion phase maintains the chondrogenic potential as well as enhance their proliferation. However, the population of hBMSCs supplemented with bFGF has not been investigated enough yet. This study aimed to analyze some characters, size and MSC markers, of the population of hBMSCs with bFGF. Methods: Bone marrow aspirates were obtained from healthy donors by routine iliac crest aspiration with their agreement and seeded to culture flasks, mixed with 2-fold volume of growth medium containing 15% lot adjusted FBS, supplemented with or without 10ng/ml bFGF (PeproTech, NJ, USA ). Non-adherent cells were removed at 3days and culture medium was changed every 3 days. At 11 to 14 days, P0 end, hBMSCs were passed to P1 and cultured with 5% FBS containing growth medium, keeping the condition of bFGF. The P1 cells were prepared for immunocytochemistry and for the confirmation of the chondrogenic ability. The size of the cells was measured with the automated Coulter cell counter at the end of P0 and P1. For immunocytochemistry, the cells at day4 on P1 stage were fixed with 4% PFA, and then Endoglin on cell surface were stained. The cells harvested at P1 end were used to perform pellet culture for 21 days. The histology sections of the pellets were stained with Safranin-O/Fast green, and the glycosaminoglycan (GAG) contents were measured and normalized with DNA (GAG/DNA), to evaluate their chondrogenic ability. The data of two groups, with or without bFGF on P0 and P1, were compared using unpaired t-test. Statistical tests were considered significant at the level of P < 0.05. Results: The size of the bFGF supplemented-hBMSCs was significantly smaller than hBMSCs without bFGF at P0 and P1, both. Most of the cells regardless with bFGF supplementation were expressed Endoglin, however bFGF supplemented-hBMSCs seemed to express Endoglin more. The pellets from the cells expanded with bFGF were bigger and histology of them showed Safranin-O stained more and contained more GAG/DNA than another as previously reported. Conclusions: The population of hBMSCs supplemented with bFGF has some distinct characters, smaller size and probably more expression of Endoglin than hBMSCs without bFGF. Endoglin has been reported as an accessory receptor for transforming growth factor-b (TGF-b) and might modulate the downstream signal molecules, such as smad-1/5/8, of hBMSCs. Gene expression level of Endoglin needs to be measured, and other MSC markers as well are going to be investigated. The cells involving in the cartilage repair would be characterized more, and if we could target and enhance this kind of the cells with any other agent than bFGF during cartilage repair process, better cartilage repair might be acquired. Synovial Tissue Biology & Biochemistry 635 DIFFERENTIAL SYNOVIAL EXPRESSION PATTERNS BETWEEN PATIENTS WITH PROGRESSION OF CARTILAGE DAMAGE AND PROGRESSION OF OSTEOPHYTE FORMATION IN EARLY OSTEOARTHRITIS A.B. Blom y, M.H. van den Bosch y, H. Cats z, F.H. van den Hoogen yz, F.P. Lafeber x, W.B. van den Berg y, P.L. van Lent y, P.M. van der Kraan y. yRadboud Univ. Med. Ctr. Nijmegen, Nijmegen, Netherlands; z Sint Maartenskliniek, Nijmegen, Netherlands; xUniv. Med. Ctr., Utrecht,