Next, the cells are transferred to a bioreactor, which is a computer-controlled, closed-system environment where large-scale production begins. These nutrients, or 'medium,' contain a combination of vitamins, amino acids, minerals, and sugar, but they do not contain any human or animal components. This flask contains nutrients the cells need to grow and produce rhBMP-2. To produce rhBMP-2, a vial of the production cells is placed into a glass spinner flask. PHASE 2: PRODUCING, PURIFYING, AND STERILIZING rhBMP-2 Because only a few recombined cells are needed to make many millions of rhBMP-2 units and future cell banks, the isolation and cloning process doesn't need to be repeated. To safely maintain the cells, the small vials are frozen at -135☌ and stored in secure, monitored, temperature-controlled freezers. This bank is the source for all future production of rhBMP-2. This replication process results in a homogeneous population of cells that can produce rhBMP-2.Ī single batch of rhBMP-2 production cells is grown and distributed into several hundred small vials, called a cell bank. Recombinant refers to the insertion, or recombination, of the gene into the production cell.Īs these recombined cells grow and multiply, they include the new gene in their DNA. Once it was isolated, it was spliced and then recombined into the DNA of a commonly used mammalian cell, called a production cell. The process began by first identifying and isolating the specific gene that carries the code for making bone morphogenetic protein-2. PHASE 1: IDENTIFYING, REPLICATING, AND STORING THE HUMAN GENE FOR BMP-2 This tightly controlled process of manufacturing rhBMP-2 ensures consistency and sterility of pure solutions of BMP. This protein is a replication of bone morphogenetic protein-2 (BMP-2), which occurs naturally in humans and is important in healing and regenerating bone. The key element to Infuse bone graft is rhBMP-2 which is manufactured using well-established molecular biology techniques. The rate of bone formation, the amount of bone formed, and the density of the resulting bone are positively correlated with both the concentration of rhBMP-2 and the length of time that rhBMP-2 is present at the implant site. The ability of rhBMP-2 to induce new bone formation depends on its concentration. Pre-clinical studies support that the bone formation started by rhBMP-2/ACS is self-limiting, forming a predictable amount of bone at the site of implantation. The bone formation process develops from the outside of the rhBMP-2/ACS implant towards the center until the entire implant is replaced by trabecular bone. Blood vessel formation (angiogenesis) is observed at the same time. Step 5: Bone formationĪs the sponge degrades or dissolves, these stem cells differentiate into osteoblast and begin to form trabecular bone and/or cartilage. The researchers concluded that BMP-2, BMP-6, and BMP-9 may be the most potent agents to induce osteoblast lineage-specific differentiation of mesenchymal stem cells. Alkaline phosphatase activity - a measure of the amount of new bone formation - was significantly increased in all three cell lines by BMP-2, BMP-6, and BMP-9. 20 Three cell lines, representing the different stages of osteoblast differentiation, were each tested. 3-19Ī 2003 in-vitro study compared the bone-forming activity of 14 recombinant human bone morphogenetic proteins. 1 Pre-clinical studies have shown that rhBMP-2 can cause the differentiation of precursor cells into osteoblasts. 2, 7 In-vitro studies of rhBMP-2 support the fact that differentiation of mesenchymal stem cells into bone-forming osteoblasts plays an essential role in the induction of new bone. 3-7 Step 4: Differentiationīinding to specific receptors on the surface of the MSC, rhBMP-2 causes them to differentiate into bone-forming cells. In-vitro studies have shown that rhBMP-2 can increase the proliferation of several multipotent cell lines, which can differentiate into osteoblasts, or bone-forming cells. The mesenchymal stem cells around the rhBMP-2/ACS implant increase in number. Mesenchymal stem cells (MSC) move from bleeding bone, muscle, and the periosteum to infiltrate the implant. This cell migration stimulated by a chemical response is called chemotaxis. Step 2: Chemotaxisīone-forming cells migrate to the area of the rhBMP-2/ACS implant. Only when they're used together do they initiate the bone induction process. Neither the rhBMP-2 nor the ACS can produce new bone tissue independently. When rhBMP-2 is placed on an ACS and implanted in the body, it produces new bone tissue at the site of implantation.
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