Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.

Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were cultured for up to 16 days, 7 days of which the cells were in the presence of various concentrations of rhBMP-2 (0, 10, 100, and 1,000 ng/mL) in order to evaluate osteogenic expression. Scanning electron microscopy (SEM), light microscopy (LM), energy dispersive spectroscopy (EDS), DNA and calcium (Ca) content measurements, and x-ray diffraction (XRD) analysis were performed. SEM and EDS evaluation showed that a confluent layer of cells was present on top of the meshes together with collagen bundles and calcified globular accretions. Light microscopical evaluation showed a densely stained layer in the upper part of the mesh. SEM and Ca content measurement showed that calcification starts at 8 days. In addition, it was demonstrated that DNA content peaked at 8 days. LM, SEM, and Ca content evaluation revealed positive effects of increasing the cell seeding density, the rhBMP-2 concentration and the culture time on mineralization. Increasing the cell seeding density also showed a positive effect on DNA content. No effects of rhBMP-2 concentration were seen on DNA content. Finally, XRD revealed that the deposited matrix contained a precipitate of a stable calcium phosphate phase. We conclude that (1) titanium fiber mesh sustains excellent osteogenic expression in vitro, (2) increasing the cell seeding density has a positive effect on osteogenic expression in titanium mesh in vitro, and (3) in high density specimens, rhBMP-2 concentrations of 100 ng/mL and 1,000 ng/mL stimulate extracellular matrix calcification in a dose-responsive manner.

A one stage versus two stage surgical technique. Tissue reaction to a percutaneous device provided with titanium fiber mesh applicable for peritoneal dialysis.

A percutaneous device, provided with a sintered titanium fiber web structure, was designed for implantation in soft tissue. The percutaneous device was inserted by a two stage surgical technique. Between the insertion of the subcutaneous and percutaneous part was an intervening healing period of 3 months. However, most clinicians prefer a one stage implant. Therefore, the authors wanted to investigate the soft tissue response to one stage and two stage percutaneous devices. The implants were inserted in the flanks of 12 goat. In each goat, one one stage and one two stage implant were placed and inspected on a regular base. It appeared that, during the experiments, significantly more one stage devices were extruded. Four months after the second surgical session, all successful implants with their surrounding tissues were retrieved for light microscopic and histomorphometric analysis. No difference in epidermal downgrowth and sulcus width was demonstrated between the implants. Furthermore, the fiber mesh was surrounded by a thin fibrous capsule free from inflammatory cells. Inside the fiber mesh structure, connective tissue was present with only scattered foci of inflammatory cells. An enhanced inflammatory tissue response was found inside the titanium mesh of one stage compared to two stage implants. This study showed that the two stage surgical procedure for implantation of a percutaneous device worked better than the one-stage surgical technique.