Influence of polymeric additives on the biological properties of brushite cements: an experimental study in rabbit

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Association of porous hydroxyapatite and bone marrow cells for bone regeneration

The preparation of hybrid material with osteoinductive capacity may be achieved by association of cultured autologous bone cells with a porous ceramic vehicle. We optimized culture conditions for rabbit marrow stromal stem cells (MSCs), notably by selection from batches of fetal calf serum. Rabbit MSCs formed colony-forming unit-fibroblastic (CFU-Fs) in vitro. Their alkaline phosphatase (ALP) activity was doubled in the presence of dexamethasone. Autologous rabbit serum allowed the formation of ALP-positive CFU-Fs, but results were highly variable depending on the rabbit. We tested the osteogenic potential of autologous cultured (with or without dexamethasone addition in the culture medium) and noncultured rabbit MSCs associated with a porous hydroxyapatite ceramic after a dorsal intramuscular implantation. Nucleated cells (107 or 108/mL) were used for the preparation of autologous hybrid material. A significantly higher number of implants containing bone was obtained with a suspension of 107 cells/mL cultured in the presence of 10−8 M dexamethasone. Some positive implants were also obtained with a suspension of 108 noncultured cells/mL. We demonstrated the feasibility of preparing rabbit autologous hybrid materials following a process for controlling culture conditions, cell characterization and cell/material association

Histological aspects in bone regeneration of an association with porous hydroxyapatite and bone marrow cells

The osteogenic potential of an association of two kinds of hydroxyapatite (HA) porous ceramics with autologous bone marrow cells cultured with or without dexamethasone (10-8M) addition in the culture medium and non-cultured rabbit marrow stromal stem cells (MSCs) was tested after 4 weeks of implantation in the dorsal muscles of spine in rabbit. A significantly higher number of rabbits with implants containing bone tissue inside pores were obtained with 107 cells ml-1 cultured treated with Dex. In the HA porous ceramic using naphtalen as porogen agent, the bone recolonization remains only at the periphery of implants and in the second row of pores, while in the HA porous ceramic using polymethacrylate (PMMA) microbeads as porogen agent, the bone recolonization is observed in the depth of implants. In the PMMA HA group, the Kru¨skal–Wallis variance analysis between the rabbits is significantly different with the percentage of number of occupied pores and occupied pores with bone tissue is different (p < 0.05)